LCOV - code coverage report
Current view: top level - drivers/tty/serial - serial_core.c (source / functions) Hit Total Coverage
Test: landlock.info Lines: 409 1480 27.6 %
Date: 2021-04-22 12:43:58 Functions: 38 94 40.4 %

          Line data    Source code
       1             : // SPDX-License-Identifier: GPL-2.0+
       2             : /*
       3             :  *  Driver core for serial ports
       4             :  *
       5             :  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
       6             :  *
       7             :  *  Copyright 1999 ARM Limited
       8             :  *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
       9             :  */
      10             : #include <linux/module.h>
      11             : #include <linux/tty.h>
      12             : #include <linux/tty_flip.h>
      13             : #include <linux/slab.h>
      14             : #include <linux/sched/signal.h>
      15             : #include <linux/init.h>
      16             : #include <linux/console.h>
      17             : #include <linux/gpio/consumer.h>
      18             : #include <linux/of.h>
      19             : #include <linux/proc_fs.h>
      20             : #include <linux/seq_file.h>
      21             : #include <linux/device.h>
      22             : #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
      23             : #include <linux/serial_core.h>
      24             : #include <linux/sysrq.h>
      25             : #include <linux/delay.h>
      26             : #include <linux/mutex.h>
      27             : #include <linux/security.h>
      28             : 
      29             : #include <linux/irq.h>
      30             : #include <linux/uaccess.h>
      31             : 
      32             : /*
      33             :  * This is used to lock changes in serial line configuration.
      34             :  */
      35             : static DEFINE_MUTEX(port_mutex);
      36             : 
      37             : /*
      38             :  * lockdep: port->lock is initialized in two places, but we
      39             :  *          want only one lock-class:
      40             :  */
      41             : static struct lock_class_key port_lock_key;
      42             : 
      43             : #define HIGH_BITS_OFFSET        ((sizeof(long)-sizeof(int))*8)
      44             : 
      45             : static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
      46             :                                         struct ktermios *old_termios);
      47             : static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
      48             : static void uart_change_pm(struct uart_state *state,
      49             :                            enum uart_pm_state pm_state);
      50             : 
      51             : static void uart_port_shutdown(struct tty_port *port);
      52             : 
      53           0 : static int uart_dcd_enabled(struct uart_port *uport)
      54             : {
      55           0 :         return !!(uport->status & UPSTAT_DCD_ENABLE);
      56             : }
      57             : 
      58        1363 : static inline struct uart_port *uart_port_ref(struct uart_state *state)
      59             : {
      60        2726 :         if (atomic_add_unless(&state->refcount, 1, 0))
      61        1363 :                 return state->uart_port;
      62             :         return NULL;
      63             : }
      64             : 
      65        1363 : static inline void uart_port_deref(struct uart_port *uport)
      66             : {
      67        2726 :         if (atomic_dec_and_test(&uport->state->refcount))
      68           0 :                 wake_up(&uport->state->remove_wait);
      69        1363 : }
      70             : 
      71             : #define uart_port_lock(state, flags)                                    \
      72             :         ({                                                              \
      73             :                 struct uart_port *__uport = uart_port_ref(state);       \
      74             :                 if (__uport)                                            \
      75             :                         spin_lock_irqsave(&__uport->lock, flags);        \
      76             :                 __uport;                                                \
      77             :         })
      78             : 
      79             : #define uart_port_unlock(uport, flags)                                  \
      80             :         ({                                                              \
      81             :                 struct uart_port *__uport = uport;                      \
      82             :                 if (__uport) {                                          \
      83             :                         spin_unlock_irqrestore(&__uport->lock, flags);   \
      84             :                         uart_port_deref(__uport);                       \
      85             :                 }                                                       \
      86             :         })
      87             : 
      88         145 : static inline struct uart_port *uart_port_check(struct uart_state *state)
      89             : {
      90         290 :         lockdep_assert_held(&state->port.mutex);
      91         145 :         return state->uart_port;
      92             : }
      93             : 
      94             : /*
      95             :  * This routine is used by the interrupt handler to schedule processing in
      96             :  * the software interrupt portion of the driver.
      97             :  */
      98         712 : void uart_write_wakeup(struct uart_port *port)
      99             : {
     100         712 :         struct uart_state *state = port->state;
     101             :         /*
     102             :          * This means you called this function _after_ the port was
     103             :          * closed.  No cookie for you.
     104             :          */
     105         712 :         BUG_ON(!state);
     106         712 :         tty_port_tty_wakeup(&state->port);
     107         712 : }
     108             : 
     109           0 : static void uart_stop(struct tty_struct *tty)
     110             : {
     111           0 :         struct uart_state *state = tty->driver_data;
     112           0 :         struct uart_port *port;
     113           0 :         unsigned long flags;
     114             : 
     115           0 :         port = uart_port_lock(state, flags);
     116           0 :         if (port)
     117           0 :                 port->ops->stop_tx(port);
     118           0 :         uart_port_unlock(port, flags);
     119           0 : }
     120             : 
     121         397 : static void __uart_start(struct tty_struct *tty)
     122             : {
     123         397 :         struct uart_state *state = tty->driver_data;
     124         397 :         struct uart_port *port = state->uart_port;
     125             : 
     126         397 :         if (port && !uart_tx_stopped(port))
     127         397 :                 port->ops->start_tx(port);
     128         397 : }
     129             : 
     130         131 : static void uart_start(struct tty_struct *tty)
     131             : {
     132         131 :         struct uart_state *state = tty->driver_data;
     133         131 :         struct uart_port *port;
     134         131 :         unsigned long flags;
     135             : 
     136         131 :         port = uart_port_lock(state, flags);
     137         131 :         __uart_start(tty);
     138         131 :         uart_port_unlock(port, flags);
     139         131 : }
     140             : 
     141             : static void
     142         135 : uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
     143             : {
     144         135 :         unsigned long flags;
     145         135 :         unsigned int old;
     146             : 
     147         135 :         spin_lock_irqsave(&port->lock, flags);
     148         135 :         old = port->mctrl;
     149         135 :         port->mctrl = (old & ~clear) | set;
     150         135 :         if (old != port->mctrl)
     151           1 :                 port->ops->set_mctrl(port, port->mctrl);
     152         135 :         spin_unlock_irqrestore(&port->lock, flags);
     153         135 : }
     154             : 
     155             : #define uart_set_mctrl(port, set)       uart_update_mctrl(port, set, 0)
     156             : #define uart_clear_mctrl(port, clear)   uart_update_mctrl(port, 0, clear)
     157             : 
     158         135 : static void uart_port_dtr_rts(struct uart_port *uport, int raise)
     159             : {
     160         135 :         int rs485_on = uport->rs485_config &&
     161           0 :                 (uport->rs485.flags & SER_RS485_ENABLED);
     162         135 :         int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);
     163             : 
     164         135 :         if (raise) {
     165         135 :                 if (rs485_on && !RTS_after_send) {
     166           0 :                         uart_set_mctrl(uport, TIOCM_DTR);
     167           0 :                         uart_clear_mctrl(uport, TIOCM_RTS);
     168             :                 } else {
     169         135 :                         uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
     170             :                 }
     171             :         } else {
     172           0 :                 unsigned int clear = TIOCM_DTR;
     173             : 
     174           0 :                 clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;
     175           0 :                 uart_clear_mctrl(uport, clear);
     176             :         }
     177         135 : }
     178             : 
     179             : /*
     180             :  * Startup the port.  This will be called once per open.  All calls
     181             :  * will be serialised by the per-port mutex.
     182             :  */
     183           1 : static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
     184             :                 int init_hw)
     185             : {
     186           1 :         struct uart_port *uport = uart_port_check(state);
     187           1 :         unsigned long page;
     188           1 :         unsigned long flags = 0;
     189           1 :         int retval = 0;
     190             : 
     191           1 :         if (uport->type == PORT_UNKNOWN)
     192             :                 return 1;
     193             : 
     194             :         /*
     195             :          * Make sure the device is in D0 state.
     196             :          */
     197           1 :         uart_change_pm(state, UART_PM_STATE_ON);
     198             : 
     199             :         /*
     200             :          * Initialise and allocate the transmit and temporary
     201             :          * buffer.
     202             :          */
     203           1 :         page = get_zeroed_page(GFP_KERNEL);
     204           1 :         if (!page)
     205             :                 return -ENOMEM;
     206             : 
     207           1 :         uart_port_lock(state, flags);
     208           1 :         if (!state->xmit.buf) {
     209           1 :                 state->xmit.buf = (unsigned char *) page;
     210           1 :                 uart_circ_clear(&state->xmit);
     211           1 :                 uart_port_unlock(uport, flags);
     212             :         } else {
     213           0 :                 uart_port_unlock(uport, flags);
     214             :                 /*
     215             :                  * Do not free() the page under the port lock, see
     216             :                  * uart_shutdown().
     217             :                  */
     218           0 :                 free_page(page);
     219             :         }
     220             : 
     221           1 :         retval = uport->ops->startup(uport);
     222           1 :         if (retval == 0) {
     223           1 :                 if (uart_console(uport) && uport->cons->cflag) {
     224           1 :                         tty->termios.c_cflag = uport->cons->cflag;
     225           1 :                         uport->cons->cflag = 0;
     226             :                 }
     227             :                 /*
     228             :                  * Initialise the hardware port settings.
     229             :                  */
     230           1 :                 uart_change_speed(tty, state, NULL);
     231             : 
     232             :                 /*
     233             :                  * Setup the RTS and DTR signals once the
     234             :                  * port is open and ready to respond.
     235             :                  */
     236           1 :                 if (init_hw && C_BAUD(tty))
     237           0 :                         uart_port_dtr_rts(uport, 1);
     238             :         }
     239             : 
     240             :         /*
     241             :          * This is to allow setserial on this port. People may want to set
     242             :          * port/irq/type and then reconfigure the port properly if it failed
     243             :          * now.
     244             :          */
     245           1 :         if (retval && capable(CAP_SYS_ADMIN))
     246           0 :                 return 1;
     247             : 
     248             :         return retval;
     249             : }
     250             : 
     251           1 : static int uart_startup(struct tty_struct *tty, struct uart_state *state,
     252             :                 int init_hw)
     253             : {
     254           1 :         struct tty_port *port = &state->port;
     255           1 :         int retval;
     256             : 
     257           1 :         if (tty_port_initialized(port))
     258             :                 return 0;
     259             : 
     260           1 :         retval = uart_port_startup(tty, state, init_hw);
     261           1 :         if (retval)
     262           0 :                 set_bit(TTY_IO_ERROR, &tty->flags);
     263             : 
     264             :         return retval;
     265             : }
     266             : 
     267             : /*
     268             :  * This routine will shutdown a serial port; interrupts are disabled, and
     269             :  * DTR is dropped if the hangup on close termio flag is on.  Calls to
     270             :  * uart_shutdown are serialised by the per-port semaphore.
     271             :  *
     272             :  * uport == NULL if uart_port has already been removed
     273             :  */
     274           0 : static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
     275             : {
     276           0 :         struct uart_port *uport = uart_port_check(state);
     277           0 :         struct tty_port *port = &state->port;
     278           0 :         unsigned long flags = 0;
     279           0 :         char *xmit_buf = NULL;
     280             : 
     281             :         /*
     282             :          * Set the TTY IO error marker
     283             :          */
     284           0 :         if (tty)
     285           0 :                 set_bit(TTY_IO_ERROR, &tty->flags);
     286             : 
     287           0 :         if (tty_port_initialized(port)) {
     288           0 :                 tty_port_set_initialized(port, 0);
     289             : 
     290             :                 /*
     291             :                  * Turn off DTR and RTS early.
     292             :                  */
     293           0 :                 if (uport && uart_console(uport) && tty)
     294           0 :                         uport->cons->cflag = tty->termios.c_cflag;
     295             : 
     296           0 :                 if (!tty || C_HUPCL(tty))
     297           0 :                         uart_port_dtr_rts(uport, 0);
     298             : 
     299           0 :                 uart_port_shutdown(port);
     300             :         }
     301             : 
     302             :         /*
     303             :          * It's possible for shutdown to be called after suspend if we get
     304             :          * a DCD drop (hangup) at just the right time.  Clear suspended bit so
     305             :          * we don't try to resume a port that has been shutdown.
     306             :          */
     307           0 :         tty_port_set_suspended(port, 0);
     308             : 
     309             :         /*
     310             :          * Do not free() the transmit buffer page under the port lock since
     311             :          * this can create various circular locking scenarios. For instance,
     312             :          * console driver may need to allocate/free a debug object, which
     313             :          * can endup in printk() recursion.
     314             :          */
     315           0 :         uart_port_lock(state, flags);
     316           0 :         xmit_buf = state->xmit.buf;
     317           0 :         state->xmit.buf = NULL;
     318           0 :         uart_port_unlock(uport, flags);
     319             : 
     320           0 :         if (xmit_buf)
     321           0 :                 free_page((unsigned long)xmit_buf);
     322           0 : }
     323             : 
     324             : /**
     325             :  *      uart_update_timeout - update per-port FIFO timeout.
     326             :  *      @port:  uart_port structure describing the port
     327             :  *      @cflag: termios cflag value
     328             :  *      @baud:  speed of the port
     329             :  *
     330             :  *      Set the port FIFO timeout value.  The @cflag value should
     331             :  *      reflect the actual hardware settings.
     332             :  */
     333             : void
     334           2 : uart_update_timeout(struct uart_port *port, unsigned int cflag,
     335             :                     unsigned int baud)
     336             : {
     337           2 :         unsigned int bits;
     338             : 
     339             :         /* byte size and parity */
     340           2 :         switch (cflag & CSIZE) {
     341             :         case CS5:
     342             :                 bits = 7;
     343             :                 break;
     344           0 :         case CS6:
     345           0 :                 bits = 8;
     346           0 :                 break;
     347           0 :         case CS7:
     348           0 :                 bits = 9;
     349           0 :                 break;
     350           2 :         default:
     351           2 :                 bits = 10;
     352           2 :                 break; /* CS8 */
     353             :         }
     354             : 
     355           2 :         if (cflag & CSTOPB)
     356           0 :                 bits++;
     357           2 :         if (cflag & PARENB)
     358           0 :                 bits++;
     359             : 
     360             :         /*
     361             :          * The total number of bits to be transmitted in the fifo.
     362             :          */
     363           2 :         bits = bits * port->fifosize;
     364             : 
     365             :         /*
     366             :          * Figure the timeout to send the above number of bits.
     367             :          * Add .02 seconds of slop
     368             :          */
     369           2 :         port->timeout = (HZ * bits) / baud + HZ/50;
     370           2 : }
     371             : 
     372             : EXPORT_SYMBOL(uart_update_timeout);
     373             : 
     374             : /**
     375             :  *      uart_get_baud_rate - return baud rate for a particular port
     376             :  *      @port: uart_port structure describing the port in question.
     377             :  *      @termios: desired termios settings.
     378             :  *      @old: old termios (or NULL)
     379             :  *      @min: minimum acceptable baud rate
     380             :  *      @max: maximum acceptable baud rate
     381             :  *
     382             :  *      Decode the termios structure into a numeric baud rate,
     383             :  *      taking account of the magic 38400 baud rate (with spd_*
     384             :  *      flags), and mapping the %B0 rate to 9600 baud.
     385             :  *
     386             :  *      If the new baud rate is invalid, try the old termios setting.
     387             :  *      If it's still invalid, we try 9600 baud.
     388             :  *
     389             :  *      Update the @termios structure to reflect the baud rate
     390             :  *      we're actually going to be using. Don't do this for the case
     391             :  *      where B0 is requested ("hang up").
     392             :  */
     393             : unsigned int
     394           2 : uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
     395             :                    struct ktermios *old, unsigned int min, unsigned int max)
     396             : {
     397           2 :         unsigned int try;
     398           2 :         unsigned int baud;
     399           2 :         unsigned int altbaud;
     400           2 :         int hung_up = 0;
     401           2 :         upf_t flags = port->flags & UPF_SPD_MASK;
     402             : 
     403           2 :         switch (flags) {
     404             :         case UPF_SPD_HI:
     405             :                 altbaud = 57600;
     406             :                 break;
     407           0 :         case UPF_SPD_VHI:
     408           0 :                 altbaud = 115200;
     409           0 :                 break;
     410           0 :         case UPF_SPD_SHI:
     411           0 :                 altbaud = 230400;
     412           0 :                 break;
     413           0 :         case UPF_SPD_WARP:
     414           0 :                 altbaud = 460800;
     415           0 :                 break;
     416           2 :         default:
     417           2 :                 altbaud = 38400;
     418           2 :                 break;
     419             :         }
     420             : 
     421           2 :         for (try = 0; try < 2; try++) {
     422           2 :                 baud = tty_termios_baud_rate(termios);
     423             : 
     424             :                 /*
     425             :                  * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
     426             :                  * Die! Die! Die!
     427             :                  */
     428           2 :                 if (try == 0 && baud == 38400)
     429           0 :                         baud = altbaud;
     430             : 
     431             :                 /*
     432             :                  * Special case: B0 rate.
     433             :                  */
     434           2 :                 if (baud == 0) {
     435           0 :                         hung_up = 1;
     436           0 :                         baud = 9600;
     437             :                 }
     438             : 
     439           2 :                 if (baud >= min && baud <= max)
     440           2 :                         return baud;
     441             : 
     442             :                 /*
     443             :                  * Oops, the quotient was zero.  Try again with
     444             :                  * the old baud rate if possible.
     445             :                  */
     446           0 :                 termios->c_cflag &= ~CBAUD;
     447           0 :                 if (old) {
     448           0 :                         baud = tty_termios_baud_rate(old);
     449           0 :                         if (!hung_up)
     450           0 :                                 tty_termios_encode_baud_rate(termios,
     451             :                                                                 baud, baud);
     452           0 :                         old = NULL;
     453           0 :                         continue;
     454             :                 }
     455             : 
     456             :                 /*
     457             :                  * As a last resort, if the range cannot be met then clip to
     458             :                  * the nearest chip supported rate.
     459             :                  */
     460           0 :                 if (!hung_up) {
     461           0 :                         if (baud <= min)
     462           0 :                                 tty_termios_encode_baud_rate(termios,
     463             :                                                         min + 1, min + 1);
     464             :                         else
     465           0 :                                 tty_termios_encode_baud_rate(termios,
     466             :                                                         max - 1, max - 1);
     467             :                 }
     468             :         }
     469             :         /* Should never happen */
     470           0 :         WARN_ON(1);
     471           0 :         return 0;
     472             : }
     473             : 
     474             : EXPORT_SYMBOL(uart_get_baud_rate);
     475             : 
     476             : /**
     477             :  *      uart_get_divisor - return uart clock divisor
     478             :  *      @port: uart_port structure describing the port.
     479             :  *      @baud: desired baud rate
     480             :  *
     481             :  *      Calculate the uart clock divisor for the port.
     482             :  */
     483             : unsigned int
     484           2 : uart_get_divisor(struct uart_port *port, unsigned int baud)
     485             : {
     486           2 :         unsigned int quot;
     487             : 
     488             :         /*
     489             :          * Old custom speed handling.
     490             :          */
     491           2 :         if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
     492           0 :                 quot = port->custom_divisor;
     493             :         else
     494           2 :                 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
     495             : 
     496           2 :         return quot;
     497             : }
     498             : 
     499             : EXPORT_SYMBOL(uart_get_divisor);
     500             : 
     501             : /* Caller holds port mutex */
     502           1 : static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
     503             :                                         struct ktermios *old_termios)
     504             : {
     505           1 :         struct uart_port *uport = uart_port_check(state);
     506           1 :         struct ktermios *termios;
     507           1 :         int hw_stopped;
     508             : 
     509             :         /*
     510             :          * If we have no tty, termios, or the port does not exist,
     511             :          * then we can't set the parameters for this port.
     512             :          */
     513           1 :         if (!tty || uport->type == PORT_UNKNOWN)
     514             :                 return;
     515             : 
     516           1 :         termios = &tty->termios;
     517           1 :         uport->ops->set_termios(uport, termios, old_termios);
     518             : 
     519             :         /*
     520             :          * Set modem status enables based on termios cflag
     521             :          */
     522           1 :         spin_lock_irq(&uport->lock);
     523           1 :         if (termios->c_cflag & CRTSCTS)
     524           0 :                 uport->status |= UPSTAT_CTS_ENABLE;
     525             :         else
     526           1 :                 uport->status &= ~UPSTAT_CTS_ENABLE;
     527             : 
     528           1 :         if (termios->c_cflag & CLOCAL)
     529           1 :                 uport->status &= ~UPSTAT_DCD_ENABLE;
     530             :         else
     531           0 :                 uport->status |= UPSTAT_DCD_ENABLE;
     532             : 
     533             :         /* reset sw-assisted CTS flow control based on (possibly) new mode */
     534           1 :         hw_stopped = uport->hw_stopped;
     535           1 :         uport->hw_stopped = uart_softcts_mode(uport) &&
     536           0 :                                 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
     537           1 :         if (uport->hw_stopped) {
     538           0 :                 if (!hw_stopped)
     539           0 :                         uport->ops->stop_tx(uport);
     540             :         } else {
     541           1 :                 if (hw_stopped)
     542           0 :                         __uart_start(tty);
     543             :         }
     544           1 :         spin_unlock_irq(&uport->lock);
     545             : }
     546             : 
     547           0 : static int uart_put_char(struct tty_struct *tty, unsigned char c)
     548             : {
     549           0 :         struct uart_state *state = tty->driver_data;
     550           0 :         struct uart_port *port;
     551           0 :         struct circ_buf *circ;
     552           0 :         unsigned long flags;
     553           0 :         int ret = 0;
     554             : 
     555           0 :         circ = &state->xmit;
     556           0 :         port = uart_port_lock(state, flags);
     557           0 :         if (!circ->buf) {
     558           0 :                 uart_port_unlock(port, flags);
     559           0 :                 return 0;
     560             :         }
     561             : 
     562           0 :         if (port && uart_circ_chars_free(circ) != 0) {
     563           0 :                 circ->buf[circ->head] = c;
     564           0 :                 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
     565           0 :                 ret = 1;
     566             :         }
     567           0 :         uart_port_unlock(port, flags);
     568             :         return ret;
     569             : }
     570             : 
     571         131 : static void uart_flush_chars(struct tty_struct *tty)
     572             : {
     573         131 :         uart_start(tty);
     574         131 : }
     575             : 
     576         266 : static int uart_write(struct tty_struct *tty,
     577             :                                         const unsigned char *buf, int count)
     578             : {
     579         266 :         struct uart_state *state = tty->driver_data;
     580         266 :         struct uart_port *port;
     581         266 :         struct circ_buf *circ;
     582         266 :         unsigned long flags;
     583         266 :         int c, ret = 0;
     584             : 
     585             :         /*
     586             :          * This means you called this function _after_ the port was
     587             :          * closed.  No cookie for you.
     588             :          */
     589         266 :         if (!state) {
     590           0 :                 WARN_ON(1);
     591           0 :                 return -EL3HLT;
     592             :         }
     593             : 
     594         266 :         port = uart_port_lock(state, flags);
     595         266 :         circ = &state->xmit;
     596         266 :         if (!circ->buf) {
     597           0 :                 uart_port_unlock(port, flags);
     598           0 :                 return 0;
     599             :         }
     600             : 
     601         532 :         while (port) {
     602         532 :                 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
     603         532 :                 if (count < c)
     604             :                         c = count;
     605         532 :                 if (c <= 0)
     606             :                         break;
     607         266 :                 memcpy(circ->buf + circ->head, buf, c);
     608         266 :                 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
     609         266 :                 buf += c;
     610         266 :                 count -= c;
     611         266 :                 ret += c;
     612             :         }
     613             : 
     614         266 :         __uart_start(tty);
     615         266 :         uart_port_unlock(port, flags);
     616             :         return ret;
     617             : }
     618             : 
     619         266 : static int uart_write_room(struct tty_struct *tty)
     620             : {
     621         266 :         struct uart_state *state = tty->driver_data;
     622         266 :         struct uart_port *port;
     623         266 :         unsigned long flags;
     624         266 :         int ret;
     625             : 
     626         266 :         port = uart_port_lock(state, flags);
     627         266 :         ret = uart_circ_chars_free(&state->xmit);
     628         266 :         uart_port_unlock(port, flags);
     629         266 :         return ret;
     630             : }
     631             : 
     632         428 : static int uart_chars_in_buffer(struct tty_struct *tty)
     633             : {
     634         428 :         struct uart_state *state = tty->driver_data;
     635         428 :         struct uart_port *port;
     636         428 :         unsigned long flags;
     637         428 :         int ret;
     638             : 
     639         428 :         port = uart_port_lock(state, flags);
     640         428 :         ret = uart_circ_chars_pending(&state->xmit);
     641         428 :         uart_port_unlock(port, flags);
     642         428 :         return ret;
     643             : }
     644             : 
     645           1 : static void uart_flush_buffer(struct tty_struct *tty)
     646             : {
     647           1 :         struct uart_state *state = tty->driver_data;
     648           1 :         struct uart_port *port;
     649           1 :         unsigned long flags;
     650             : 
     651             :         /*
     652             :          * This means you called this function _after_ the port was
     653             :          * closed.  No cookie for you.
     654             :          */
     655           1 :         if (!state) {
     656           0 :                 WARN_ON(1);
     657           0 :                 return;
     658             :         }
     659             : 
     660           1 :         pr_debug("uart_flush_buffer(%d) called\n", tty->index);
     661             : 
     662           1 :         port = uart_port_lock(state, flags);
     663           1 :         if (!port)
     664             :                 return;
     665           1 :         uart_circ_clear(&state->xmit);
     666           1 :         if (port->ops->flush_buffer)
     667           0 :                 port->ops->flush_buffer(port);
     668           1 :         uart_port_unlock(port, flags);
     669           1 :         tty_port_tty_wakeup(&state->port);
     670             : }
     671             : 
     672             : /*
     673             :  * This function is used to send a high-priority XON/XOFF character to
     674             :  * the device
     675             :  */
     676           0 : static void uart_send_xchar(struct tty_struct *tty, char ch)
     677             : {
     678           0 :         struct uart_state *state = tty->driver_data;
     679           0 :         struct uart_port *port;
     680           0 :         unsigned long flags;
     681             : 
     682           0 :         port = uart_port_ref(state);
     683           0 :         if (!port)
     684             :                 return;
     685             : 
     686           0 :         if (port->ops->send_xchar)
     687           0 :                 port->ops->send_xchar(port, ch);
     688             :         else {
     689           0 :                 spin_lock_irqsave(&port->lock, flags);
     690           0 :                 port->x_char = ch;
     691           0 :                 if (ch)
     692           0 :                         port->ops->start_tx(port);
     693           0 :                 spin_unlock_irqrestore(&port->lock, flags);
     694             :         }
     695           0 :         uart_port_deref(port);
     696             : }
     697             : 
     698           0 : static void uart_throttle(struct tty_struct *tty)
     699             : {
     700           0 :         struct uart_state *state = tty->driver_data;
     701           0 :         upstat_t mask = UPSTAT_SYNC_FIFO;
     702           0 :         struct uart_port *port;
     703             : 
     704           0 :         port = uart_port_ref(state);
     705           0 :         if (!port)
     706             :                 return;
     707             : 
     708           0 :         if (I_IXOFF(tty))
     709           0 :                 mask |= UPSTAT_AUTOXOFF;
     710           0 :         if (C_CRTSCTS(tty))
     711           0 :                 mask |= UPSTAT_AUTORTS;
     712             : 
     713           0 :         if (port->status & mask) {
     714           0 :                 port->ops->throttle(port);
     715           0 :                 mask &= ~port->status;
     716             :         }
     717             : 
     718           0 :         if (mask & UPSTAT_AUTORTS)
     719           0 :                 uart_clear_mctrl(port, TIOCM_RTS);
     720             : 
     721           0 :         if (mask & UPSTAT_AUTOXOFF)
     722           0 :                 uart_send_xchar(tty, STOP_CHAR(tty));
     723             : 
     724           0 :         uart_port_deref(port);
     725             : }
     726             : 
     727           0 : static void uart_unthrottle(struct tty_struct *tty)
     728             : {
     729           0 :         struct uart_state *state = tty->driver_data;
     730           0 :         upstat_t mask = UPSTAT_SYNC_FIFO;
     731           0 :         struct uart_port *port;
     732             : 
     733           0 :         port = uart_port_ref(state);
     734           0 :         if (!port)
     735             :                 return;
     736             : 
     737           0 :         if (I_IXOFF(tty))
     738           0 :                 mask |= UPSTAT_AUTOXOFF;
     739           0 :         if (C_CRTSCTS(tty))
     740           0 :                 mask |= UPSTAT_AUTORTS;
     741             : 
     742           0 :         if (port->status & mask) {
     743           0 :                 port->ops->unthrottle(port);
     744           0 :                 mask &= ~port->status;
     745             :         }
     746             : 
     747           0 :         if (mask & UPSTAT_AUTORTS)
     748           0 :                 uart_set_mctrl(port, TIOCM_RTS);
     749             : 
     750           0 :         if (mask & UPSTAT_AUTOXOFF)
     751           0 :                 uart_send_xchar(tty, START_CHAR(tty));
     752             : 
     753           0 :         uart_port_deref(port);
     754             : }
     755             : 
     756           0 : static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
     757             : {
     758           0 :         struct uart_state *state = container_of(port, struct uart_state, port);
     759           0 :         struct uart_port *uport;
     760           0 :         int ret = -ENODEV;
     761             : 
     762           0 :         memset(retinfo, 0, sizeof(*retinfo));
     763             : 
     764             :         /*
     765             :          * Ensure the state we copy is consistent and no hardware changes
     766             :          * occur as we go
     767             :          */
     768           0 :         mutex_lock(&port->mutex);
     769           0 :         uport = uart_port_check(state);
     770           0 :         if (!uport)
     771           0 :                 goto out;
     772             : 
     773           0 :         retinfo->type            = uport->type;
     774           0 :         retinfo->line            = uport->line;
     775           0 :         retinfo->port            = uport->iobase;
     776           0 :         if (HIGH_BITS_OFFSET)
     777           0 :                 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
     778           0 :         retinfo->irq             = uport->irq;
     779           0 :         retinfo->flags           = (__force int)uport->flags;
     780           0 :         retinfo->xmit_fifo_size  = uport->fifosize;
     781           0 :         retinfo->baud_base       = uport->uartclk / 16;
     782           0 :         retinfo->close_delay     = jiffies_to_msecs(port->close_delay) / 10;
     783           0 :         retinfo->closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
     784             :                                 ASYNC_CLOSING_WAIT_NONE :
     785           0 :                                 jiffies_to_msecs(port->closing_wait) / 10;
     786           0 :         retinfo->custom_divisor  = uport->custom_divisor;
     787           0 :         retinfo->hub6            = uport->hub6;
     788           0 :         retinfo->io_type         = uport->iotype;
     789           0 :         retinfo->iomem_reg_shift = uport->regshift;
     790           0 :         retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;
     791             : 
     792           0 :         ret = 0;
     793           0 : out:
     794           0 :         mutex_unlock(&port->mutex);
     795           0 :         return ret;
     796             : }
     797             : 
     798           0 : static int uart_get_info_user(struct tty_struct *tty,
     799             :                          struct serial_struct *ss)
     800             : {
     801           0 :         struct uart_state *state = tty->driver_data;
     802           0 :         struct tty_port *port = &state->port;
     803             : 
     804           0 :         return uart_get_info(port, ss) < 0 ? -EIO : 0;
     805             : }
     806             : 
     807           0 : static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
     808             :                          struct uart_state *state,
     809             :                          struct serial_struct *new_info)
     810             : {
     811           0 :         struct uart_port *uport = uart_port_check(state);
     812           0 :         unsigned long new_port;
     813           0 :         unsigned int change_irq, change_port, closing_wait;
     814           0 :         unsigned int old_custom_divisor, close_delay;
     815           0 :         upf_t old_flags, new_flags;
     816           0 :         int retval = 0;
     817             : 
     818           0 :         if (!uport)
     819             :                 return -EIO;
     820             : 
     821           0 :         new_port = new_info->port;
     822           0 :         if (HIGH_BITS_OFFSET)
     823           0 :                 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
     824             : 
     825           0 :         new_info->irq = irq_canonicalize(new_info->irq);
     826           0 :         close_delay = msecs_to_jiffies(new_info->close_delay * 10);
     827           0 :         closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
     828             :                         ASYNC_CLOSING_WAIT_NONE :
     829           0 :                         msecs_to_jiffies(new_info->closing_wait * 10);
     830             : 
     831             : 
     832           0 :         change_irq  = !(uport->flags & UPF_FIXED_PORT)
     833           0 :                 && new_info->irq != uport->irq;
     834             : 
     835             :         /*
     836             :          * Since changing the 'type' of the port changes its resource
     837             :          * allocations, we should treat type changes the same as
     838             :          * IO port changes.
     839             :          */
     840           0 :         change_port = !(uport->flags & UPF_FIXED_PORT)
     841           0 :                 && (new_port != uport->iobase ||
     842           0 :                     (unsigned long)new_info->iomem_base != uport->mapbase ||
     843           0 :                     new_info->hub6 != uport->hub6 ||
     844           0 :                     new_info->io_type != uport->iotype ||
     845           0 :                     new_info->iomem_reg_shift != uport->regshift ||
     846           0 :                     new_info->type != uport->type);
     847             : 
     848           0 :         old_flags = uport->flags;
     849           0 :         new_flags = (__force upf_t)new_info->flags;
     850           0 :         old_custom_divisor = uport->custom_divisor;
     851             : 
     852           0 :         if (!capable(CAP_SYS_ADMIN)) {
     853           0 :                 retval = -EPERM;
     854           0 :                 if (change_irq || change_port ||
     855           0 :                     (new_info->baud_base != uport->uartclk / 16) ||
     856           0 :                     (close_delay != port->close_delay) ||
     857           0 :                     (closing_wait != port->closing_wait) ||
     858           0 :                     (new_info->xmit_fifo_size &&
     859           0 :                      new_info->xmit_fifo_size != uport->fifosize) ||
     860           0 :                     (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
     861           0 :                         goto exit;
     862           0 :                 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
     863           0 :                                (new_flags & UPF_USR_MASK));
     864           0 :                 uport->custom_divisor = new_info->custom_divisor;
     865           0 :                 goto check_and_exit;
     866             :         }
     867             : 
     868           0 :         retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
     869           0 :         if (retval && (change_irq || change_port))
     870           0 :                 goto exit;
     871             : 
     872             :         /*
     873             :          * Ask the low level driver to verify the settings.
     874             :          */
     875           0 :         if (uport->ops->verify_port)
     876           0 :                 retval = uport->ops->verify_port(uport, new_info);
     877             : 
     878           0 :         if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
     879           0 :             (new_info->baud_base < 9600))
     880             :                 retval = -EINVAL;
     881             : 
     882           0 :         if (retval)
     883           0 :                 goto exit;
     884             : 
     885           0 :         if (change_port || change_irq) {
     886           0 :                 retval = -EBUSY;
     887             : 
     888             :                 /*
     889             :                  * Make sure that we are the sole user of this port.
     890             :                  */
     891           0 :                 if (tty_port_users(port) > 1)
     892           0 :                         goto exit;
     893             : 
     894             :                 /*
     895             :                  * We need to shutdown the serial port at the old
     896             :                  * port/type/irq combination.
     897             :                  */
     898           0 :                 uart_shutdown(tty, state);
     899             :         }
     900             : 
     901           0 :         if (change_port) {
     902           0 :                 unsigned long old_iobase, old_mapbase;
     903           0 :                 unsigned int old_type, old_iotype, old_hub6, old_shift;
     904             : 
     905           0 :                 old_iobase = uport->iobase;
     906           0 :                 old_mapbase = uport->mapbase;
     907           0 :                 old_type = uport->type;
     908           0 :                 old_hub6 = uport->hub6;
     909           0 :                 old_iotype = uport->iotype;
     910           0 :                 old_shift = uport->regshift;
     911             : 
     912             :                 /*
     913             :                  * Free and release old regions
     914             :                  */
     915           0 :                 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
     916           0 :                         uport->ops->release_port(uport);
     917             : 
     918           0 :                 uport->iobase = new_port;
     919           0 :                 uport->type = new_info->type;
     920           0 :                 uport->hub6 = new_info->hub6;
     921           0 :                 uport->iotype = new_info->io_type;
     922           0 :                 uport->regshift = new_info->iomem_reg_shift;
     923           0 :                 uport->mapbase = (unsigned long)new_info->iomem_base;
     924             : 
     925             :                 /*
     926             :                  * Claim and map the new regions
     927             :                  */
     928           0 :                 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
     929           0 :                         retval = uport->ops->request_port(uport);
     930             :                 } else {
     931             :                         /* Always success - Jean II */
     932             :                         retval = 0;
     933             :                 }
     934             : 
     935             :                 /*
     936             :                  * If we fail to request resources for the
     937             :                  * new port, try to restore the old settings.
     938             :                  */
     939           0 :                 if (retval) {
     940           0 :                         uport->iobase = old_iobase;
     941           0 :                         uport->type = old_type;
     942           0 :                         uport->hub6 = old_hub6;
     943           0 :                         uport->iotype = old_iotype;
     944           0 :                         uport->regshift = old_shift;
     945           0 :                         uport->mapbase = old_mapbase;
     946             : 
     947           0 :                         if (old_type != PORT_UNKNOWN) {
     948           0 :                                 retval = uport->ops->request_port(uport);
     949             :                                 /*
     950             :                                  * If we failed to restore the old settings,
     951             :                                  * we fail like this.
     952             :                                  */
     953           0 :                                 if (retval)
     954           0 :                                         uport->type = PORT_UNKNOWN;
     955             : 
     956             :                                 /*
     957             :                                  * We failed anyway.
     958             :                                  */
     959             :                                 retval = -EBUSY;
     960             :                         }
     961             : 
     962             :                         /* Added to return the correct error -Ram Gupta */
     963           0 :                         goto exit;
     964             :                 }
     965             :         }
     966             : 
     967           0 :         if (change_irq)
     968           0 :                 uport->irq      = new_info->irq;
     969           0 :         if (!(uport->flags & UPF_FIXED_PORT))
     970           0 :                 uport->uartclk  = new_info->baud_base * 16;
     971           0 :         uport->flags            = (uport->flags & ~UPF_CHANGE_MASK) |
     972           0 :                                  (new_flags & UPF_CHANGE_MASK);
     973           0 :         uport->custom_divisor   = new_info->custom_divisor;
     974           0 :         port->close_delay     = close_delay;
     975           0 :         port->closing_wait    = closing_wait;
     976           0 :         if (new_info->xmit_fifo_size)
     977           0 :                 uport->fifosize = new_info->xmit_fifo_size;
     978             : 
     979           0 :  check_and_exit:
     980           0 :         retval = 0;
     981           0 :         if (uport->type == PORT_UNKNOWN)
     982           0 :                 goto exit;
     983           0 :         if (tty_port_initialized(port)) {
     984           0 :                 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
     985           0 :                     old_custom_divisor != uport->custom_divisor) {
     986             :                         /*
     987             :                          * If they're setting up a custom divisor or speed,
     988             :                          * instead of clearing it, then bitch about it.
     989             :                          */
     990           0 :                         if (uport->flags & UPF_SPD_MASK) {
     991           0 :                                 dev_notice_ratelimited(uport->dev,
     992             :                                        "%s sets custom speed on %s. This is deprecated.\n",
     993             :                                       current->comm,
     994             :                                       tty_name(port->tty));
     995             :                         }
     996           0 :                         uart_change_speed(tty, state, NULL);
     997             :                 }
     998             :         } else {
     999           0 :                 retval = uart_startup(tty, state, 1);
    1000           0 :                 if (retval == 0)
    1001           0 :                         tty_port_set_initialized(port, true);
    1002           0 :                 if (retval > 0)
    1003             :                         retval = 0;
    1004             :         }
    1005           0 :  exit:
    1006             :         return retval;
    1007             : }
    1008             : 
    1009           0 : static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
    1010             : {
    1011           0 :         struct uart_state *state = tty->driver_data;
    1012           0 :         struct tty_port *port = &state->port;
    1013           0 :         int retval;
    1014             : 
    1015           0 :         down_write(&tty->termios_rwsem);
    1016             :         /*
    1017             :          * This semaphore protects port->count.  It is also
    1018             :          * very useful to prevent opens.  Also, take the
    1019             :          * port configuration semaphore to make sure that a
    1020             :          * module insertion/removal doesn't change anything
    1021             :          * under us.
    1022             :          */
    1023           0 :         mutex_lock(&port->mutex);
    1024           0 :         retval = uart_set_info(tty, port, state, ss);
    1025           0 :         mutex_unlock(&port->mutex);
    1026           0 :         up_write(&tty->termios_rwsem);
    1027           0 :         return retval;
    1028             : }
    1029             : 
    1030             : /**
    1031             :  *      uart_get_lsr_info       -       get line status register info
    1032             :  *      @tty: tty associated with the UART
    1033             :  *      @state: UART being queried
    1034             :  *      @value: returned modem value
    1035             :  */
    1036           0 : static int uart_get_lsr_info(struct tty_struct *tty,
    1037             :                         struct uart_state *state, unsigned int __user *value)
    1038             : {
    1039           0 :         struct uart_port *uport = uart_port_check(state);
    1040           0 :         unsigned int result;
    1041             : 
    1042           0 :         result = uport->ops->tx_empty(uport);
    1043             : 
    1044             :         /*
    1045             :          * If we're about to load something into the transmit
    1046             :          * register, we'll pretend the transmitter isn't empty to
    1047             :          * avoid a race condition (depending on when the transmit
    1048             :          * interrupt happens).
    1049             :          */
    1050           0 :         if (uport->x_char ||
    1051           0 :             ((uart_circ_chars_pending(&state->xmit) > 0) &&
    1052           0 :              !uart_tx_stopped(uport)))
    1053           0 :                 result &= ~TIOCSER_TEMT;
    1054             : 
    1055           0 :         return put_user(result, value);
    1056             : }
    1057             : 
    1058           0 : static int uart_tiocmget(struct tty_struct *tty)
    1059             : {
    1060           0 :         struct uart_state *state = tty->driver_data;
    1061           0 :         struct tty_port *port = &state->port;
    1062           0 :         struct uart_port *uport;
    1063           0 :         int result = -EIO;
    1064             : 
    1065           0 :         mutex_lock(&port->mutex);
    1066           0 :         uport = uart_port_check(state);
    1067           0 :         if (!uport)
    1068           0 :                 goto out;
    1069             : 
    1070           0 :         if (!tty_io_error(tty)) {
    1071           0 :                 result = uport->mctrl;
    1072           0 :                 spin_lock_irq(&uport->lock);
    1073           0 :                 result |= uport->ops->get_mctrl(uport);
    1074           0 :                 spin_unlock_irq(&uport->lock);
    1075             :         }
    1076           0 : out:
    1077           0 :         mutex_unlock(&port->mutex);
    1078           0 :         return result;
    1079             : }
    1080             : 
    1081             : static int
    1082           0 : uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
    1083             : {
    1084           0 :         struct uart_state *state = tty->driver_data;
    1085           0 :         struct tty_port *port = &state->port;
    1086           0 :         struct uart_port *uport;
    1087           0 :         int ret = -EIO;
    1088             : 
    1089           0 :         mutex_lock(&port->mutex);
    1090           0 :         uport = uart_port_check(state);
    1091           0 :         if (!uport)
    1092           0 :                 goto out;
    1093             : 
    1094           0 :         if (!tty_io_error(tty)) {
    1095           0 :                 uart_update_mctrl(uport, set, clear);
    1096           0 :                 ret = 0;
    1097             :         }
    1098           0 : out:
    1099           0 :         mutex_unlock(&port->mutex);
    1100           0 :         return ret;
    1101             : }
    1102             : 
    1103           0 : static int uart_break_ctl(struct tty_struct *tty, int break_state)
    1104             : {
    1105           0 :         struct uart_state *state = tty->driver_data;
    1106           0 :         struct tty_port *port = &state->port;
    1107           0 :         struct uart_port *uport;
    1108           0 :         int ret = -EIO;
    1109             : 
    1110           0 :         mutex_lock(&port->mutex);
    1111           0 :         uport = uart_port_check(state);
    1112           0 :         if (!uport)
    1113           0 :                 goto out;
    1114             : 
    1115           0 :         if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
    1116           0 :                 uport->ops->break_ctl(uport, break_state);
    1117             :         ret = 0;
    1118           0 : out:
    1119           0 :         mutex_unlock(&port->mutex);
    1120           0 :         return ret;
    1121             : }
    1122             : 
    1123           0 : static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
    1124             : {
    1125           0 :         struct tty_port *port = &state->port;
    1126           0 :         struct uart_port *uport;
    1127           0 :         int flags, ret;
    1128             : 
    1129           0 :         if (!capable(CAP_SYS_ADMIN))
    1130             :                 return -EPERM;
    1131             : 
    1132             :         /*
    1133             :          * Take the per-port semaphore.  This prevents count from
    1134             :          * changing, and hence any extra opens of the port while
    1135             :          * we're auto-configuring.
    1136             :          */
    1137           0 :         if (mutex_lock_interruptible(&port->mutex))
    1138             :                 return -ERESTARTSYS;
    1139             : 
    1140           0 :         uport = uart_port_check(state);
    1141           0 :         if (!uport) {
    1142           0 :                 ret = -EIO;
    1143           0 :                 goto out;
    1144             :         }
    1145             : 
    1146           0 :         ret = -EBUSY;
    1147           0 :         if (tty_port_users(port) == 1) {
    1148           0 :                 uart_shutdown(tty, state);
    1149             : 
    1150             :                 /*
    1151             :                  * If we already have a port type configured,
    1152             :                  * we must release its resources.
    1153             :                  */
    1154           0 :                 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
    1155           0 :                         uport->ops->release_port(uport);
    1156             : 
    1157           0 :                 flags = UART_CONFIG_TYPE;
    1158           0 :                 if (uport->flags & UPF_AUTO_IRQ)
    1159           0 :                         flags |= UART_CONFIG_IRQ;
    1160             : 
    1161             :                 /*
    1162             :                  * This will claim the ports resources if
    1163             :                  * a port is found.
    1164             :                  */
    1165           0 :                 uport->ops->config_port(uport, flags);
    1166             : 
    1167           0 :                 ret = uart_startup(tty, state, 1);
    1168           0 :                 if (ret == 0)
    1169           0 :                         tty_port_set_initialized(port, true);
    1170           0 :                 if (ret > 0)
    1171             :                         ret = 0;
    1172             :         }
    1173           0 : out:
    1174           0 :         mutex_unlock(&port->mutex);
    1175           0 :         return ret;
    1176             : }
    1177             : 
    1178           0 : static void uart_enable_ms(struct uart_port *uport)
    1179             : {
    1180             :         /*
    1181             :          * Force modem status interrupts on
    1182             :          */
    1183           0 :         if (uport->ops->enable_ms)
    1184           0 :                 uport->ops->enable_ms(uport);
    1185             : }
    1186             : 
    1187             : /*
    1188             :  * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
    1189             :  * - mask passed in arg for lines of interest
    1190             :  *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
    1191             :  * Caller should use TIOCGICOUNT to see which one it was
    1192             :  *
    1193             :  * FIXME: This wants extracting into a common all driver implementation
    1194             :  * of TIOCMWAIT using tty_port.
    1195             :  */
    1196           0 : static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
    1197             : {
    1198           0 :         struct uart_port *uport;
    1199           0 :         struct tty_port *port = &state->port;
    1200           0 :         DECLARE_WAITQUEUE(wait, current);
    1201           0 :         struct uart_icount cprev, cnow;
    1202           0 :         int ret;
    1203             : 
    1204             :         /*
    1205             :          * note the counters on entry
    1206             :          */
    1207           0 :         uport = uart_port_ref(state);
    1208           0 :         if (!uport)
    1209             :                 return -EIO;
    1210           0 :         spin_lock_irq(&uport->lock);
    1211           0 :         memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
    1212           0 :         uart_enable_ms(uport);
    1213           0 :         spin_unlock_irq(&uport->lock);
    1214             : 
    1215           0 :         add_wait_queue(&port->delta_msr_wait, &wait);
    1216           0 :         for (;;) {
    1217           0 :                 spin_lock_irq(&uport->lock);
    1218           0 :                 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
    1219           0 :                 spin_unlock_irq(&uport->lock);
    1220             : 
    1221           0 :                 set_current_state(TASK_INTERRUPTIBLE);
    1222             : 
    1223           0 :                 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
    1224           0 :                     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
    1225           0 :                     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
    1226           0 :                     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
    1227             :                         ret = 0;
    1228             :                         break;
    1229             :                 }
    1230             : 
    1231           0 :                 schedule();
    1232             : 
    1233             :                 /* see if a signal did it */
    1234           0 :                 if (signal_pending(current)) {
    1235             :                         ret = -ERESTARTSYS;
    1236             :                         break;
    1237             :                 }
    1238             : 
    1239           0 :                 cprev = cnow;
    1240             :         }
    1241           0 :         __set_current_state(TASK_RUNNING);
    1242           0 :         remove_wait_queue(&port->delta_msr_wait, &wait);
    1243           0 :         uart_port_deref(uport);
    1244             : 
    1245           0 :         return ret;
    1246             : }
    1247             : 
    1248             : /*
    1249             :  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
    1250             :  * Return: write counters to the user passed counter struct
    1251             :  * NB: both 1->0 and 0->1 transitions are counted except for
    1252             :  *     RI where only 0->1 is counted.
    1253             :  */
    1254           0 : static int uart_get_icount(struct tty_struct *tty,
    1255             :                           struct serial_icounter_struct *icount)
    1256             : {
    1257           0 :         struct uart_state *state = tty->driver_data;
    1258           0 :         struct uart_icount cnow;
    1259           0 :         struct uart_port *uport;
    1260             : 
    1261           0 :         uport = uart_port_ref(state);
    1262           0 :         if (!uport)
    1263             :                 return -EIO;
    1264           0 :         spin_lock_irq(&uport->lock);
    1265           0 :         memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
    1266           0 :         spin_unlock_irq(&uport->lock);
    1267           0 :         uart_port_deref(uport);
    1268             : 
    1269           0 :         icount->cts         = cnow.cts;
    1270           0 :         icount->dsr         = cnow.dsr;
    1271           0 :         icount->rng         = cnow.rng;
    1272           0 :         icount->dcd         = cnow.dcd;
    1273           0 :         icount->rx          = cnow.rx;
    1274           0 :         icount->tx          = cnow.tx;
    1275           0 :         icount->frame       = cnow.frame;
    1276           0 :         icount->overrun     = cnow.overrun;
    1277           0 :         icount->parity      = cnow.parity;
    1278           0 :         icount->brk         = cnow.brk;
    1279           0 :         icount->buf_overrun = cnow.buf_overrun;
    1280             : 
    1281           0 :         return 0;
    1282             : }
    1283             : 
    1284           0 : static int uart_get_rs485_config(struct uart_port *port,
    1285             :                          struct serial_rs485 __user *rs485)
    1286             : {
    1287           0 :         unsigned long flags;
    1288           0 :         struct serial_rs485 aux;
    1289             : 
    1290           0 :         spin_lock_irqsave(&port->lock, flags);
    1291           0 :         aux = port->rs485;
    1292           0 :         spin_unlock_irqrestore(&port->lock, flags);
    1293             : 
    1294           0 :         if (copy_to_user(rs485, &aux, sizeof(aux)))
    1295           0 :                 return -EFAULT;
    1296             : 
    1297             :         return 0;
    1298             : }
    1299             : 
    1300           0 : static int uart_set_rs485_config(struct uart_port *port,
    1301             :                          struct serial_rs485 __user *rs485_user)
    1302             : {
    1303           0 :         struct serial_rs485 rs485;
    1304           0 :         int ret;
    1305           0 :         unsigned long flags;
    1306             : 
    1307           0 :         if (!port->rs485_config)
    1308             :                 return -ENOIOCTLCMD;
    1309             : 
    1310           0 :         if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
    1311             :                 return -EFAULT;
    1312             : 
    1313           0 :         spin_lock_irqsave(&port->lock, flags);
    1314           0 :         ret = port->rs485_config(port, &rs485);
    1315           0 :         spin_unlock_irqrestore(&port->lock, flags);
    1316           0 :         if (ret)
    1317             :                 return ret;
    1318             : 
    1319           0 :         if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
    1320           0 :                 return -EFAULT;
    1321             : 
    1322             :         return 0;
    1323             : }
    1324             : 
    1325           0 : static int uart_get_iso7816_config(struct uart_port *port,
    1326             :                                    struct serial_iso7816 __user *iso7816)
    1327             : {
    1328           0 :         unsigned long flags;
    1329           0 :         struct serial_iso7816 aux;
    1330             : 
    1331           0 :         if (!port->iso7816_config)
    1332             :                 return -ENOIOCTLCMD;
    1333             : 
    1334           0 :         spin_lock_irqsave(&port->lock, flags);
    1335           0 :         aux = port->iso7816;
    1336           0 :         spin_unlock_irqrestore(&port->lock, flags);
    1337             : 
    1338           0 :         if (copy_to_user(iso7816, &aux, sizeof(aux)))
    1339           0 :                 return -EFAULT;
    1340             : 
    1341             :         return 0;
    1342             : }
    1343             : 
    1344           0 : static int uart_set_iso7816_config(struct uart_port *port,
    1345             :                                    struct serial_iso7816 __user *iso7816_user)
    1346             : {
    1347           0 :         struct serial_iso7816 iso7816;
    1348           0 :         int i, ret;
    1349           0 :         unsigned long flags;
    1350             : 
    1351           0 :         if (!port->iso7816_config)
    1352             :                 return -ENOIOCTLCMD;
    1353             : 
    1354           0 :         if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
    1355             :                 return -EFAULT;
    1356             : 
    1357             :         /*
    1358             :          * There are 5 words reserved for future use. Check that userspace
    1359             :          * doesn't put stuff in there to prevent breakages in the future.
    1360             :          */
    1361           0 :         for (i = 0; i < 5; i++)
    1362           0 :                 if (iso7816.reserved[i])
    1363             :                         return -EINVAL;
    1364             : 
    1365           0 :         spin_lock_irqsave(&port->lock, flags);
    1366           0 :         ret = port->iso7816_config(port, &iso7816);
    1367           0 :         spin_unlock_irqrestore(&port->lock, flags);
    1368           0 :         if (ret)
    1369             :                 return ret;
    1370             : 
    1371           0 :         if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
    1372           0 :                 return -EFAULT;
    1373             : 
    1374             :         return 0;
    1375             : }
    1376             : 
    1377             : /*
    1378             :  * Called via sys_ioctl.  We can use spin_lock_irq() here.
    1379             :  */
    1380             : static int
    1381         139 : uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
    1382             : {
    1383         139 :         struct uart_state *state = tty->driver_data;
    1384         139 :         struct tty_port *port = &state->port;
    1385         139 :         struct uart_port *uport;
    1386         139 :         void __user *uarg = (void __user *)arg;
    1387         139 :         int ret = -ENOIOCTLCMD;
    1388             : 
    1389             : 
    1390             :         /*
    1391             :          * These ioctls don't rely on the hardware to be present.
    1392             :          */
    1393         139 :         switch (cmd) {
    1394           0 :         case TIOCSERCONFIG:
    1395           0 :                 down_write(&tty->termios_rwsem);
    1396           0 :                 ret = uart_do_autoconfig(tty, state);
    1397           0 :                 up_write(&tty->termios_rwsem);
    1398           0 :                 break;
    1399             :         }
    1400             : 
    1401           0 :         if (ret != -ENOIOCTLCMD)
    1402           0 :                 goto out;
    1403             : 
    1404         139 :         if (tty_io_error(tty)) {
    1405           0 :                 ret = -EIO;
    1406           0 :                 goto out;
    1407             :         }
    1408             : 
    1409             :         /*
    1410             :          * The following should only be used when hardware is present.
    1411             :          */
    1412         139 :         switch (cmd) {
    1413           0 :         case TIOCMIWAIT:
    1414           0 :                 ret = uart_wait_modem_status(state, arg);
    1415           0 :                 break;
    1416             :         }
    1417             : 
    1418         139 :         if (ret != -ENOIOCTLCMD)
    1419           0 :                 goto out;
    1420             : 
    1421         139 :         mutex_lock(&port->mutex);
    1422         139 :         uport = uart_port_check(state);
    1423             : 
    1424         278 :         if (!uport || tty_io_error(tty)) {
    1425           0 :                 ret = -EIO;
    1426           0 :                 goto out_up;
    1427             :         }
    1428             : 
    1429             :         /*
    1430             :          * All these rely on hardware being present and need to be
    1431             :          * protected against the tty being hung up.
    1432             :          */
    1433             : 
    1434         139 :         switch (cmd) {
    1435           0 :         case TIOCSERGETLSR: /* Get line status register */
    1436           0 :                 ret = uart_get_lsr_info(tty, state, uarg);
    1437           0 :                 break;
    1438             : 
    1439           0 :         case TIOCGRS485:
    1440           0 :                 ret = uart_get_rs485_config(uport, uarg);
    1441           0 :                 break;
    1442             : 
    1443           0 :         case TIOCSRS485:
    1444           0 :                 ret = uart_set_rs485_config(uport, uarg);
    1445           0 :                 break;
    1446             : 
    1447           0 :         case TIOCSISO7816:
    1448           0 :                 ret = uart_set_iso7816_config(state->uart_port, uarg);
    1449           0 :                 break;
    1450             : 
    1451           0 :         case TIOCGISO7816:
    1452           0 :                 ret = uart_get_iso7816_config(state->uart_port, uarg);
    1453           0 :                 break;
    1454         139 :         default:
    1455         139 :                 if (uport->ops->ioctl)
    1456           0 :                         ret = uport->ops->ioctl(uport, cmd, arg);
    1457             :                 break;
    1458             :         }
    1459         139 : out_up:
    1460         139 :         mutex_unlock(&port->mutex);
    1461         139 : out:
    1462         139 :         return ret;
    1463             : }
    1464             : 
    1465           0 : static void uart_set_ldisc(struct tty_struct *tty)
    1466             : {
    1467           0 :         struct uart_state *state = tty->driver_data;
    1468           0 :         struct uart_port *uport;
    1469           0 :         struct tty_port *port = &state->port;
    1470             : 
    1471           0 :         if (!tty_port_initialized(port))
    1472             :                 return;
    1473             : 
    1474           0 :         mutex_lock(&state->port.mutex);
    1475           0 :         uport = uart_port_check(state);
    1476           0 :         if (uport && uport->ops->set_ldisc)
    1477           0 :                 uport->ops->set_ldisc(uport, &tty->termios);
    1478           0 :         mutex_unlock(&state->port.mutex);
    1479             : }
    1480             : 
    1481           1 : static void uart_set_termios(struct tty_struct *tty,
    1482             :                                                 struct ktermios *old_termios)
    1483             : {
    1484           1 :         struct uart_state *state = tty->driver_data;
    1485           1 :         struct uart_port *uport;
    1486           1 :         unsigned int cflag = tty->termios.c_cflag;
    1487           1 :         unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
    1488           1 :         bool sw_changed = false;
    1489             : 
    1490           1 :         mutex_lock(&state->port.mutex);
    1491           1 :         uport = uart_port_check(state);
    1492           1 :         if (!uport)
    1493           0 :                 goto out;
    1494             : 
    1495             :         /*
    1496             :          * Drivers doing software flow control also need to know
    1497             :          * about changes to these input settings.
    1498             :          */
    1499           1 :         if (uport->flags & UPF_SOFT_FLOW) {
    1500           0 :                 iflag_mask |= IXANY|IXON|IXOFF;
    1501           0 :                 sw_changed =
    1502           0 :                    tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
    1503             :                    tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
    1504             :         }
    1505             : 
    1506             :         /*
    1507             :          * These are the bits that are used to setup various
    1508             :          * flags in the low level driver. We can ignore the Bfoo
    1509             :          * bits in c_cflag; c_[io]speed will always be set
    1510             :          * appropriately by set_termios() in tty_ioctl.c
    1511             :          */
    1512           1 :         if ((cflag ^ old_termios->c_cflag) == 0 &&
    1513           1 :             tty->termios.c_ospeed == old_termios->c_ospeed &&
    1514           1 :             tty->termios.c_ispeed == old_termios->c_ispeed &&
    1515           1 :             ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
    1516             :             !sw_changed) {
    1517           1 :                 goto out;
    1518             :         }
    1519             : 
    1520           0 :         uart_change_speed(tty, state, old_termios);
    1521             :         /* reload cflag from termios; port driver may have overridden flags */
    1522           0 :         cflag = tty->termios.c_cflag;
    1523             : 
    1524             :         /* Handle transition to B0 status */
    1525           0 :         if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
    1526           0 :                 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
    1527             :         /* Handle transition away from B0 status */
    1528           0 :         else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
    1529           0 :                 unsigned int mask = TIOCM_DTR;
    1530             : 
    1531           0 :                 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
    1532             :                         mask |= TIOCM_RTS;
    1533           0 :                 uart_set_mctrl(uport, mask);
    1534             :         }
    1535           0 : out:
    1536           1 :         mutex_unlock(&state->port.mutex);
    1537           1 : }
    1538             : 
    1539             : /*
    1540             :  * Calls to uart_close() are serialised via the tty_lock in
    1541             :  *   drivers/tty/tty_io.c:tty_release()
    1542             :  *   drivers/tty/tty_io.c:do_tty_hangup()
    1543             :  */
    1544         135 : static void uart_close(struct tty_struct *tty, struct file *filp)
    1545             : {
    1546         135 :         struct uart_state *state = tty->driver_data;
    1547             : 
    1548         135 :         if (!state) {
    1549           0 :                 struct uart_driver *drv = tty->driver->driver_state;
    1550           0 :                 struct tty_port *port;
    1551             : 
    1552           0 :                 state = drv->state + tty->index;
    1553           0 :                 port = &state->port;
    1554           0 :                 spin_lock_irq(&port->lock);
    1555           0 :                 --port->count;
    1556           0 :                 spin_unlock_irq(&port->lock);
    1557           0 :                 return;
    1558             :         }
    1559             : 
    1560         135 :         pr_debug("uart_close(%d) called\n", tty->index);
    1561             : 
    1562         135 :         tty_port_close(tty->port, tty, filp);
    1563             : }
    1564             : 
    1565           0 : static void uart_tty_port_shutdown(struct tty_port *port)
    1566             : {
    1567           0 :         struct uart_state *state = container_of(port, struct uart_state, port);
    1568           0 :         struct uart_port *uport = uart_port_check(state);
    1569             : 
    1570             :         /*
    1571             :          * At this point, we stop accepting input.  To do this, we
    1572             :          * disable the receive line status interrupts.
    1573             :          */
    1574           0 :         if (WARN(!uport, "detached port still initialized!\n"))
    1575             :                 return;
    1576             : 
    1577           0 :         spin_lock_irq(&uport->lock);
    1578           0 :         uport->ops->stop_rx(uport);
    1579           0 :         spin_unlock_irq(&uport->lock);
    1580             : 
    1581           0 :         uart_port_shutdown(port);
    1582             : 
    1583             :         /*
    1584             :          * It's possible for shutdown to be called after suspend if we get
    1585             :          * a DCD drop (hangup) at just the right time.  Clear suspended bit so
    1586             :          * we don't try to resume a port that has been shutdown.
    1587             :          */
    1588           0 :         tty_port_set_suspended(port, 0);
    1589             : 
    1590           0 :         uart_change_pm(state, UART_PM_STATE_OFF);
    1591             : 
    1592             : }
    1593             : 
    1594         135 : static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
    1595             : {
    1596         135 :         struct uart_state *state = tty->driver_data;
    1597         135 :         struct uart_port *port;
    1598         135 :         unsigned long char_time, expire;
    1599             : 
    1600         135 :         port = uart_port_ref(state);
    1601         135 :         if (!port)
    1602             :                 return;
    1603             : 
    1604         135 :         if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
    1605           0 :                 uart_port_deref(port);
    1606           0 :                 return;
    1607             :         }
    1608             : 
    1609             :         /*
    1610             :          * Set the check interval to be 1/5 of the estimated time to
    1611             :          * send a single character, and make it at least 1.  The check
    1612             :          * interval should also be less than the timeout.
    1613             :          *
    1614             :          * Note: we have to use pretty tight timings here to satisfy
    1615             :          * the NIST-PCTS.
    1616             :          */
    1617         135 :         char_time = (port->timeout - HZ/50) / port->fifosize;
    1618         135 :         char_time = char_time / 5;
    1619         135 :         if (char_time == 0)
    1620         135 :                 char_time = 1;
    1621         135 :         if (timeout && timeout < char_time)
    1622             :                 char_time = timeout;
    1623             : 
    1624             :         /*
    1625             :          * If the transmitter hasn't cleared in twice the approximate
    1626             :          * amount of time to send the entire FIFO, it probably won't
    1627             :          * ever clear.  This assumes the UART isn't doing flow
    1628             :          * control, which is currently the case.  Hence, if it ever
    1629             :          * takes longer than port->timeout, this is probably due to a
    1630             :          * UART bug of some kind.  So, we clamp the timeout parameter at
    1631             :          * 2*port->timeout.
    1632             :          */
    1633         135 :         if (timeout == 0 || timeout > 2 * port->timeout)
    1634         135 :                 timeout = 2 * port->timeout;
    1635             : 
    1636         135 :         expire = jiffies + timeout;
    1637             : 
    1638         135 :         pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
    1639             :                 port->line, jiffies, expire);
    1640             : 
    1641             :         /*
    1642             :          * Check whether the transmitter is empty every 'char_time'.
    1643             :          * 'timeout' / 'expire' give us the maximum amount of time
    1644             :          * we wait.
    1645             :          */
    1646         135 :         while (!port->ops->tx_empty(port)) {
    1647           0 :                 msleep_interruptible(jiffies_to_msecs(char_time));
    1648           0 :                 if (signal_pending(current))
    1649             :                         break;
    1650           0 :                 if (time_after(jiffies, expire))
    1651             :                         break;
    1652             :         }
    1653         135 :         uart_port_deref(port);
    1654             : }
    1655             : 
    1656             : /*
    1657             :  * Calls to uart_hangup() are serialised by the tty_lock in
    1658             :  *   drivers/tty/tty_io.c:do_tty_hangup()
    1659             :  * This runs from a workqueue and can sleep for a _short_ time only.
    1660             :  */
    1661           0 : static void uart_hangup(struct tty_struct *tty)
    1662             : {
    1663           0 :         struct uart_state *state = tty->driver_data;
    1664           0 :         struct tty_port *port = &state->port;
    1665           0 :         struct uart_port *uport;
    1666           0 :         unsigned long flags;
    1667             : 
    1668           0 :         pr_debug("uart_hangup(%d)\n", tty->index);
    1669             : 
    1670           0 :         mutex_lock(&port->mutex);
    1671           0 :         uport = uart_port_check(state);
    1672           0 :         WARN(!uport, "hangup of detached port!\n");
    1673             : 
    1674           0 :         if (tty_port_active(port)) {
    1675           0 :                 uart_flush_buffer(tty);
    1676           0 :                 uart_shutdown(tty, state);
    1677           0 :                 spin_lock_irqsave(&port->lock, flags);
    1678           0 :                 port->count = 0;
    1679           0 :                 spin_unlock_irqrestore(&port->lock, flags);
    1680           0 :                 tty_port_set_active(port, 0);
    1681           0 :                 tty_port_tty_set(port, NULL);
    1682           0 :                 if (uport && !uart_console(uport))
    1683           0 :                         uart_change_pm(state, UART_PM_STATE_OFF);
    1684           0 :                 wake_up_interruptible(&port->open_wait);
    1685           0 :                 wake_up_interruptible(&port->delta_msr_wait);
    1686             :         }
    1687           0 :         mutex_unlock(&port->mutex);
    1688           0 : }
    1689             : 
    1690             : /* uport == NULL if uart_port has already been removed */
    1691           0 : static void uart_port_shutdown(struct tty_port *port)
    1692             : {
    1693           0 :         struct uart_state *state = container_of(port, struct uart_state, port);
    1694           0 :         struct uart_port *uport = uart_port_check(state);
    1695             : 
    1696             :         /*
    1697             :          * clear delta_msr_wait queue to avoid mem leaks: we may free
    1698             :          * the irq here so the queue might never be woken up.  Note
    1699             :          * that we won't end up waiting on delta_msr_wait again since
    1700             :          * any outstanding file descriptors should be pointing at
    1701             :          * hung_up_tty_fops now.
    1702             :          */
    1703           0 :         wake_up_interruptible(&port->delta_msr_wait);
    1704             : 
    1705             :         /*
    1706             :          * Free the IRQ and disable the port.
    1707             :          */
    1708           0 :         if (uport)
    1709           0 :                 uport->ops->shutdown(uport);
    1710             : 
    1711             :         /*
    1712             :          * Ensure that the IRQ handler isn't running on another CPU.
    1713             :          */
    1714           0 :         if (uport)
    1715           0 :                 synchronize_irq(uport->irq);
    1716           0 : }
    1717             : 
    1718           0 : static int uart_carrier_raised(struct tty_port *port)
    1719             : {
    1720           0 :         struct uart_state *state = container_of(port, struct uart_state, port);
    1721           0 :         struct uart_port *uport;
    1722           0 :         int mctrl;
    1723             : 
    1724           0 :         uport = uart_port_ref(state);
    1725             :         /*
    1726             :          * Should never observe uport == NULL since checks for hangup should
    1727             :          * abort the tty_port_block_til_ready() loop before checking for carrier
    1728             :          * raised -- but report carrier raised if it does anyway so open will
    1729             :          * continue and not sleep
    1730             :          */
    1731           0 :         if (WARN_ON(!uport))
    1732             :                 return 1;
    1733           0 :         spin_lock_irq(&uport->lock);
    1734           0 :         uart_enable_ms(uport);
    1735           0 :         mctrl = uport->ops->get_mctrl(uport);
    1736           0 :         spin_unlock_irq(&uport->lock);
    1737           0 :         uart_port_deref(uport);
    1738           0 :         if (mctrl & TIOCM_CAR)
    1739           0 :                 return 1;
    1740             :         return 0;
    1741             : }
    1742             : 
    1743         135 : static void uart_dtr_rts(struct tty_port *port, int raise)
    1744             : {
    1745         135 :         struct uart_state *state = container_of(port, struct uart_state, port);
    1746         135 :         struct uart_port *uport;
    1747             : 
    1748         135 :         uport = uart_port_ref(state);
    1749         135 :         if (!uport)
    1750             :                 return;
    1751         135 :         uart_port_dtr_rts(uport, raise);
    1752         135 :         uart_port_deref(uport);
    1753             : }
    1754             : 
    1755         135 : static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
    1756             : {
    1757         135 :         struct uart_driver *drv = driver->driver_state;
    1758         135 :         struct uart_state *state = drv->state + tty->index;
    1759             : 
    1760         135 :         tty->driver_data = state;
    1761             : 
    1762         135 :         return tty_standard_install(driver, tty);
    1763             : }
    1764             : 
    1765             : /*
    1766             :  * Calls to uart_open are serialised by the tty_lock in
    1767             :  *   drivers/tty/tty_io.c:tty_open()
    1768             :  * Note that if this fails, then uart_close() _will_ be called.
    1769             :  *
    1770             :  * In time, we want to scrap the "opening nonpresent ports"
    1771             :  * behaviour and implement an alternative way for setserial
    1772             :  * to set base addresses/ports/types.  This will allow us to
    1773             :  * get rid of a certain amount of extra tests.
    1774             :  */
    1775         135 : static int uart_open(struct tty_struct *tty, struct file *filp)
    1776             : {
    1777         135 :         struct uart_state *state = tty->driver_data;
    1778         135 :         int retval;
    1779             : 
    1780         135 :         retval = tty_port_open(&state->port, tty, filp);
    1781         135 :         if (retval > 0)
    1782             :                 retval = 0;
    1783             : 
    1784         135 :         return retval;
    1785             : }
    1786             : 
    1787           1 : static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
    1788             : {
    1789           1 :         struct uart_state *state = container_of(port, struct uart_state, port);
    1790           1 :         struct uart_port *uport;
    1791           1 :         int ret;
    1792             : 
    1793           1 :         uport = uart_port_check(state);
    1794           1 :         if (!uport || uport->flags & UPF_DEAD)
    1795             :                 return -ENXIO;
    1796             : 
    1797             :         /*
    1798             :          * Start up the serial port.
    1799             :          */
    1800           1 :         ret = uart_startup(tty, state, 0);
    1801           1 :         if (ret > 0)
    1802           0 :                 tty_port_set_active(port, 1);
    1803             : 
    1804             :         return ret;
    1805             : }
    1806             : 
    1807           1 : static const char *uart_type(struct uart_port *port)
    1808             : {
    1809           1 :         const char *str = NULL;
    1810             : 
    1811           1 :         if (port->ops->type)
    1812           1 :                 str = port->ops->type(port);
    1813             : 
    1814           1 :         if (!str)
    1815             :                 str = "unknown";
    1816             : 
    1817           1 :         return str;
    1818             : }
    1819             : 
    1820             : #ifdef CONFIG_PROC_FS
    1821             : 
    1822           0 : static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
    1823             : {
    1824           0 :         struct uart_state *state = drv->state + i;
    1825           0 :         struct tty_port *port = &state->port;
    1826           0 :         enum uart_pm_state pm_state;
    1827           0 :         struct uart_port *uport;
    1828           0 :         char stat_buf[32];
    1829           0 :         unsigned int status;
    1830           0 :         int mmio;
    1831             : 
    1832           0 :         mutex_lock(&port->mutex);
    1833           0 :         uport = uart_port_check(state);
    1834           0 :         if (!uport)
    1835           0 :                 goto out;
    1836             : 
    1837           0 :         mmio = uport->iotype >= UPIO_MEM;
    1838           0 :         seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
    1839             :                         uport->line, uart_type(uport),
    1840             :                         mmio ? "mmio:0x" : "port:",
    1841             :                         mmio ? (unsigned long long)uport->mapbase
    1842             :                              : (unsigned long long)uport->iobase,
    1843             :                         uport->irq);
    1844             : 
    1845           0 :         if (uport->type == PORT_UNKNOWN) {
    1846           0 :                 seq_putc(m, '\n');
    1847           0 :                 goto out;
    1848             :         }
    1849             : 
    1850           0 :         if (capable(CAP_SYS_ADMIN)) {
    1851           0 :                 pm_state = state->pm_state;
    1852           0 :                 if (pm_state != UART_PM_STATE_ON)
    1853           0 :                         uart_change_pm(state, UART_PM_STATE_ON);
    1854           0 :                 spin_lock_irq(&uport->lock);
    1855           0 :                 status = uport->ops->get_mctrl(uport);
    1856           0 :                 spin_unlock_irq(&uport->lock);
    1857           0 :                 if (pm_state != UART_PM_STATE_ON)
    1858           0 :                         uart_change_pm(state, pm_state);
    1859             : 
    1860           0 :                 seq_printf(m, " tx:%d rx:%d",
    1861             :                                 uport->icount.tx, uport->icount.rx);
    1862           0 :                 if (uport->icount.frame)
    1863           0 :                         seq_printf(m, " fe:%d",       uport->icount.frame);
    1864           0 :                 if (uport->icount.parity)
    1865           0 :                         seq_printf(m, " pe:%d",       uport->icount.parity);
    1866           0 :                 if (uport->icount.brk)
    1867           0 :                         seq_printf(m, " brk:%d", uport->icount.brk);
    1868           0 :                 if (uport->icount.overrun)
    1869           0 :                         seq_printf(m, " oe:%d", uport->icount.overrun);
    1870           0 :                 if (uport->icount.buf_overrun)
    1871           0 :                         seq_printf(m, " bo:%d", uport->icount.buf_overrun);
    1872             : 
    1873             : #define INFOBIT(bit, str) \
    1874             :         if (uport->mctrl & (bit)) \
    1875             :                 strncat(stat_buf, (str), sizeof(stat_buf) - \
    1876             :                         strlen(stat_buf) - 2)
    1877             : #define STATBIT(bit, str) \
    1878             :         if (status & (bit)) \
    1879             :                 strncat(stat_buf, (str), sizeof(stat_buf) - \
    1880             :                        strlen(stat_buf) - 2)
    1881             : 
    1882           0 :                 stat_buf[0] = '\0';
    1883           0 :                 stat_buf[1] = '\0';
    1884           0 :                 INFOBIT(TIOCM_RTS, "|RTS");
    1885           0 :                 STATBIT(TIOCM_CTS, "|CTS");
    1886           0 :                 INFOBIT(TIOCM_DTR, "|DTR");
    1887           0 :                 STATBIT(TIOCM_DSR, "|DSR");
    1888           0 :                 STATBIT(TIOCM_CAR, "|CD");
    1889           0 :                 STATBIT(TIOCM_RNG, "|RI");
    1890           0 :                 if (stat_buf[0])
    1891           0 :                         stat_buf[0] = ' ';
    1892             : 
    1893           0 :                 seq_puts(m, stat_buf);
    1894             :         }
    1895           0 :         seq_putc(m, '\n');
    1896             : #undef STATBIT
    1897             : #undef INFOBIT
    1898           0 : out:
    1899           0 :         mutex_unlock(&port->mutex);
    1900           0 : }
    1901             : 
    1902           0 : static int uart_proc_show(struct seq_file *m, void *v)
    1903             : {
    1904           0 :         struct tty_driver *ttydrv = m->private;
    1905           0 :         struct uart_driver *drv = ttydrv->driver_state;
    1906           0 :         int i;
    1907             : 
    1908           0 :         seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
    1909           0 :         for (i = 0; i < drv->nr; i++)
    1910           0 :                 uart_line_info(m, drv, i);
    1911           0 :         return 0;
    1912             : }
    1913             : #endif
    1914             : 
    1915           5 : static inline bool uart_console_enabled(struct uart_port *port)
    1916             : {
    1917           5 :         return uart_console(port) && (port->cons->flags & CON_ENABLED);
    1918             : }
    1919             : 
    1920           4 : static void uart_port_spin_lock_init(struct uart_port *port)
    1921             : {
    1922           4 :         spin_lock_init(&port->lock);
    1923           4 :         lockdep_set_class(&port->lock, &port_lock_key);
    1924           4 : }
    1925             : 
    1926             : #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
    1927             : /**
    1928             :  *      uart_console_write - write a console message to a serial port
    1929             :  *      @port: the port to write the message
    1930             :  *      @s: array of characters
    1931             :  *      @count: number of characters in string to write
    1932             :  *      @putchar: function to write character to port
    1933             :  */
    1934         256 : void uart_console_write(struct uart_port *port, const char *s,
    1935             :                         unsigned int count,
    1936             :                         void (*putchar)(struct uart_port *, int))
    1937             : {
    1938         256 :         unsigned int i;
    1939             : 
    1940       13683 :         for (i = 0; i < count; i++, s++) {
    1941       13427 :                 if (*s == '\n')
    1942         256 :                         putchar(port, '\r');
    1943       13427 :                 putchar(port, *s);
    1944             :         }
    1945         256 : }
    1946             : EXPORT_SYMBOL_GPL(uart_console_write);
    1947             : 
    1948             : /*
    1949             :  *      Check whether an invalid uart number has been specified, and
    1950             :  *      if so, search for the first available port that does have
    1951             :  *      console support.
    1952             :  */
    1953             : struct uart_port * __init
    1954           0 : uart_get_console(struct uart_port *ports, int nr, struct console *co)
    1955             : {
    1956           0 :         int idx = co->index;
    1957             : 
    1958           0 :         if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
    1959           0 :                                      ports[idx].membase == NULL))
    1960           0 :                 for (idx = 0; idx < nr; idx++)
    1961           0 :                         if (ports[idx].iobase != 0 ||
    1962           0 :                             ports[idx].membase != NULL)
    1963             :                                 break;
    1964             : 
    1965           0 :         co->index = idx;
    1966             : 
    1967           0 :         return ports + idx;
    1968             : }
    1969             : 
    1970             : /**
    1971             :  *      uart_parse_earlycon - Parse earlycon options
    1972             :  *      @p:       ptr to 2nd field (ie., just beyond '<name>,')
    1973             :  *      @iotype:  ptr for decoded iotype (out)
    1974             :  *      @addr:    ptr for decoded mapbase/iobase (out)
    1975             :  *      @options: ptr for <options> field; NULL if not present (out)
    1976             :  *
    1977             :  *      Decodes earlycon kernel command line parameters of the form
    1978             :  *         earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
    1979             :  *         console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
    1980             :  *
    1981             :  *      The optional form
    1982             :  *
    1983             :  *         earlycon=<name>,0x<addr>,<options>
    1984             :  *         console=<name>,0x<addr>,<options>
    1985             :  *
    1986             :  *      is also accepted; the returned @iotype will be UPIO_MEM.
    1987             :  *
    1988             :  *      Returns 0 on success or -EINVAL on failure
    1989             :  */
    1990           0 : int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
    1991             :                         char **options)
    1992             : {
    1993           0 :         if (strncmp(p, "mmio,", 5) == 0) {
    1994           0 :                 *iotype = UPIO_MEM;
    1995           0 :                 p += 5;
    1996           0 :         } else if (strncmp(p, "mmio16,", 7) == 0) {
    1997           0 :                 *iotype = UPIO_MEM16;
    1998           0 :                 p += 7;
    1999           0 :         } else if (strncmp(p, "mmio32,", 7) == 0) {
    2000           0 :                 *iotype = UPIO_MEM32;
    2001           0 :                 p += 7;
    2002           0 :         } else if (strncmp(p, "mmio32be,", 9) == 0) {
    2003           0 :                 *iotype = UPIO_MEM32BE;
    2004           0 :                 p += 9;
    2005           0 :         } else if (strncmp(p, "mmio32native,", 13) == 0) {
    2006           0 :                 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
    2007             :                         UPIO_MEM32BE : UPIO_MEM32;
    2008           0 :                 p += 13;
    2009           0 :         } else if (strncmp(p, "io,", 3) == 0) {
    2010           0 :                 *iotype = UPIO_PORT;
    2011           0 :                 p += 3;
    2012           0 :         } else if (strncmp(p, "0x", 2) == 0) {
    2013           0 :                 *iotype = UPIO_MEM;
    2014             :         } else {
    2015             :                 return -EINVAL;
    2016             :         }
    2017             : 
    2018             :         /*
    2019             :          * Before you replace it with kstrtoull(), think about options separator
    2020             :          * (',') it will not tolerate
    2021             :          */
    2022           0 :         *addr = simple_strtoull(p, NULL, 0);
    2023           0 :         p = strchr(p, ',');
    2024           0 :         if (p)
    2025           0 :                 p++;
    2026             : 
    2027           0 :         *options = p;
    2028           0 :         return 0;
    2029             : }
    2030             : EXPORT_SYMBOL_GPL(uart_parse_earlycon);
    2031             : 
    2032             : /**
    2033             :  *      uart_parse_options - Parse serial port baud/parity/bits/flow control.
    2034             :  *      @options: pointer to option string
    2035             :  *      @baud: pointer to an 'int' variable for the baud rate.
    2036             :  *      @parity: pointer to an 'int' variable for the parity.
    2037             :  *      @bits: pointer to an 'int' variable for the number of data bits.
    2038             :  *      @flow: pointer to an 'int' variable for the flow control character.
    2039             :  *
    2040             :  *      uart_parse_options decodes a string containing the serial console
    2041             :  *      options.  The format of the string is <baud><parity><bits><flow>,
    2042             :  *      eg: 115200n8r
    2043             :  */
    2044             : void
    2045           0 : uart_parse_options(const char *options, int *baud, int *parity,
    2046             :                    int *bits, int *flow)
    2047             : {
    2048           0 :         const char *s = options;
    2049             : 
    2050           0 :         *baud = simple_strtoul(s, NULL, 10);
    2051           0 :         while (*s >= '0' && *s <= '9')
    2052           0 :                 s++;
    2053           0 :         if (*s)
    2054           0 :                 *parity = *s++;
    2055           0 :         if (*s)
    2056           0 :                 *bits = *s++ - '0';
    2057           0 :         if (*s)
    2058           0 :                 *flow = *s;
    2059           0 : }
    2060             : EXPORT_SYMBOL_GPL(uart_parse_options);
    2061             : 
    2062             : /**
    2063             :  *      uart_set_options - setup the serial console parameters
    2064             :  *      @port: pointer to the serial ports uart_port structure
    2065             :  *      @co: console pointer
    2066             :  *      @baud: baud rate
    2067             :  *      @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
    2068             :  *      @bits: number of data bits
    2069             :  *      @flow: flow control character - 'r' (rts)
    2070             :  */
    2071             : int
    2072           1 : uart_set_options(struct uart_port *port, struct console *co,
    2073             :                  int baud, int parity, int bits, int flow)
    2074             : {
    2075           1 :         struct ktermios termios;
    2076           1 :         static struct ktermios dummy;
    2077             : 
    2078             :         /*
    2079             :          * Ensure that the serial-console lock is initialised early.
    2080             :          *
    2081             :          * Note that the console-enabled check is needed because of kgdboc,
    2082             :          * which can end up calling uart_set_options() for an already enabled
    2083             :          * console via tty_find_polling_driver() and uart_poll_init().
    2084             :          */
    2085           1 :         if (!uart_console_enabled(port) && !port->console_reinit)
    2086           1 :                 uart_port_spin_lock_init(port);
    2087             : 
    2088           1 :         memset(&termios, 0, sizeof(struct ktermios));
    2089             : 
    2090           1 :         termios.c_cflag |= CREAD | HUPCL | CLOCAL;
    2091           1 :         tty_termios_encode_baud_rate(&termios, baud, baud);
    2092             : 
    2093           1 :         if (bits == 7)
    2094           0 :                 termios.c_cflag |= CS7;
    2095             :         else
    2096           1 :                 termios.c_cflag |= CS8;
    2097             : 
    2098           1 :         switch (parity) {
    2099           0 :         case 'o': case 'O':
    2100           0 :                 termios.c_cflag |= PARODD;
    2101           0 :                 fallthrough;
    2102           0 :         case 'e': case 'E':
    2103           0 :                 termios.c_cflag |= PARENB;
    2104           0 :                 break;
    2105             :         }
    2106             : 
    2107           1 :         if (flow == 'r')
    2108           0 :                 termios.c_cflag |= CRTSCTS;
    2109             : 
    2110             :         /*
    2111             :          * some uarts on other side don't support no flow control.
    2112             :          * So we set * DTR in host uart to make them happy
    2113             :          */
    2114           1 :         port->mctrl |= TIOCM_DTR;
    2115             : 
    2116           1 :         port->ops->set_termios(port, &termios, &dummy);
    2117             :         /*
    2118             :          * Allow the setting of the UART parameters with a NULL console
    2119             :          * too:
    2120             :          */
    2121           1 :         if (co)
    2122           1 :                 co->cflag = termios.c_cflag;
    2123             : 
    2124           1 :         return 0;
    2125             : }
    2126             : EXPORT_SYMBOL_GPL(uart_set_options);
    2127             : #endif /* CONFIG_SERIAL_CORE_CONSOLE */
    2128             : 
    2129             : /**
    2130             :  * uart_change_pm - set power state of the port
    2131             :  *
    2132             :  * @state: port descriptor
    2133             :  * @pm_state: new state
    2134             :  *
    2135             :  * Locking: port->mutex has to be held
    2136             :  */
    2137           2 : static void uart_change_pm(struct uart_state *state,
    2138             :                            enum uart_pm_state pm_state)
    2139             : {
    2140           2 :         struct uart_port *port = uart_port_check(state);
    2141             : 
    2142           2 :         if (state->pm_state != pm_state) {
    2143           1 :                 if (port && port->ops->pm)
    2144           1 :                         port->ops->pm(port, pm_state, state->pm_state);
    2145           1 :                 state->pm_state = pm_state;
    2146             :         }
    2147           2 : }
    2148             : 
    2149             : struct uart_match {
    2150             :         struct uart_port *port;
    2151             :         struct uart_driver *driver;
    2152             : };
    2153             : 
    2154           0 : static int serial_match_port(struct device *dev, void *data)
    2155             : {
    2156           0 :         struct uart_match *match = data;
    2157           0 :         struct tty_driver *tty_drv = match->driver->tty_driver;
    2158           0 :         dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
    2159           0 :                 match->port->line;
    2160             : 
    2161           0 :         return dev->devt == devt; /* Actually, only one tty per port */
    2162             : }
    2163             : 
    2164           0 : int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
    2165             : {
    2166           0 :         struct uart_state *state = drv->state + uport->line;
    2167           0 :         struct tty_port *port = &state->port;
    2168           0 :         struct device *tty_dev;
    2169           0 :         struct uart_match match = {uport, drv};
    2170             : 
    2171           0 :         mutex_lock(&port->mutex);
    2172             : 
    2173           0 :         tty_dev = device_find_child(uport->dev, &match, serial_match_port);
    2174           0 :         if (tty_dev && device_may_wakeup(tty_dev)) {
    2175           0 :                 enable_irq_wake(uport->irq);
    2176           0 :                 put_device(tty_dev);
    2177           0 :                 mutex_unlock(&port->mutex);
    2178           0 :                 return 0;
    2179             :         }
    2180           0 :         put_device(tty_dev);
    2181             : 
    2182             :         /* Nothing to do if the console is not suspending */
    2183           0 :         if (!console_suspend_enabled && uart_console(uport))
    2184           0 :                 goto unlock;
    2185             : 
    2186           0 :         uport->suspended = 1;
    2187             : 
    2188           0 :         if (tty_port_initialized(port)) {
    2189           0 :                 const struct uart_ops *ops = uport->ops;
    2190           0 :                 int tries;
    2191             : 
    2192           0 :                 tty_port_set_suspended(port, 1);
    2193           0 :                 tty_port_set_initialized(port, 0);
    2194             : 
    2195           0 :                 spin_lock_irq(&uport->lock);
    2196           0 :                 ops->stop_tx(uport);
    2197           0 :                 ops->set_mctrl(uport, 0);
    2198           0 :                 ops->stop_rx(uport);
    2199           0 :                 spin_unlock_irq(&uport->lock);
    2200             : 
    2201             :                 /*
    2202             :                  * Wait for the transmitter to empty.
    2203             :                  */
    2204           0 :                 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
    2205           0 :                         msleep(10);
    2206           0 :                 if (!tries)
    2207           0 :                         dev_err(uport->dev, "%s: Unable to drain transmitter\n",
    2208             :                                 uport->name);
    2209             : 
    2210           0 :                 ops->shutdown(uport);
    2211             :         }
    2212             : 
    2213             :         /*
    2214             :          * Disable the console device before suspending.
    2215             :          */
    2216           0 :         if (uart_console(uport))
    2217           0 :                 console_stop(uport->cons);
    2218             : 
    2219           0 :         uart_change_pm(state, UART_PM_STATE_OFF);
    2220           0 : unlock:
    2221           0 :         mutex_unlock(&port->mutex);
    2222             : 
    2223           0 :         return 0;
    2224             : }
    2225             : 
    2226           0 : int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
    2227             : {
    2228           0 :         struct uart_state *state = drv->state + uport->line;
    2229           0 :         struct tty_port *port = &state->port;
    2230           0 :         struct device *tty_dev;
    2231           0 :         struct uart_match match = {uport, drv};
    2232           0 :         struct ktermios termios;
    2233             : 
    2234           0 :         mutex_lock(&port->mutex);
    2235             : 
    2236           0 :         tty_dev = device_find_child(uport->dev, &match, serial_match_port);
    2237           0 :         if (!uport->suspended && device_may_wakeup(tty_dev)) {
    2238           0 :                 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
    2239           0 :                         disable_irq_wake(uport->irq);
    2240           0 :                 put_device(tty_dev);
    2241           0 :                 mutex_unlock(&port->mutex);
    2242           0 :                 return 0;
    2243             :         }
    2244           0 :         put_device(tty_dev);
    2245           0 :         uport->suspended = 0;
    2246             : 
    2247             :         /*
    2248             :          * Re-enable the console device after suspending.
    2249             :          */
    2250           0 :         if (uart_console(uport)) {
    2251             :                 /*
    2252             :                  * First try to use the console cflag setting.
    2253             :                  */
    2254           0 :                 memset(&termios, 0, sizeof(struct ktermios));
    2255           0 :                 termios.c_cflag = uport->cons->cflag;
    2256             : 
    2257             :                 /*
    2258             :                  * If that's unset, use the tty termios setting.
    2259             :                  */
    2260           0 :                 if (port->tty && termios.c_cflag == 0)
    2261           0 :                         termios = port->tty->termios;
    2262             : 
    2263           0 :                 if (console_suspend_enabled)
    2264           0 :                         uart_change_pm(state, UART_PM_STATE_ON);
    2265           0 :                 uport->ops->set_termios(uport, &termios, NULL);
    2266           0 :                 if (console_suspend_enabled)
    2267           0 :                         console_start(uport->cons);
    2268             :         }
    2269             : 
    2270           0 :         if (tty_port_suspended(port)) {
    2271           0 :                 const struct uart_ops *ops = uport->ops;
    2272           0 :                 int ret;
    2273             : 
    2274           0 :                 uart_change_pm(state, UART_PM_STATE_ON);
    2275           0 :                 spin_lock_irq(&uport->lock);
    2276           0 :                 ops->set_mctrl(uport, 0);
    2277           0 :                 spin_unlock_irq(&uport->lock);
    2278           0 :                 if (console_suspend_enabled || !uart_console(uport)) {
    2279             :                         /* Protected by port mutex for now */
    2280           0 :                         struct tty_struct *tty = port->tty;
    2281             : 
    2282           0 :                         ret = ops->startup(uport);
    2283           0 :                         if (ret == 0) {
    2284           0 :                                 if (tty)
    2285           0 :                                         uart_change_speed(tty, state, NULL);
    2286           0 :                                 spin_lock_irq(&uport->lock);
    2287           0 :                                 ops->set_mctrl(uport, uport->mctrl);
    2288           0 :                                 ops->start_tx(uport);
    2289           0 :                                 spin_unlock_irq(&uport->lock);
    2290           0 :                                 tty_port_set_initialized(port, 1);
    2291             :                         } else {
    2292             :                                 /*
    2293             :                                  * Failed to resume - maybe hardware went away?
    2294             :                                  * Clear the "initialized" flag so we won't try
    2295             :                                  * to call the low level drivers shutdown method.
    2296             :                                  */
    2297           0 :                                 uart_shutdown(tty, state);
    2298             :                         }
    2299             :                 }
    2300             : 
    2301           0 :                 tty_port_set_suspended(port, 0);
    2302             :         }
    2303             : 
    2304           0 :         mutex_unlock(&port->mutex);
    2305             : 
    2306           0 :         return 0;
    2307             : }
    2308             : 
    2309             : static inline void
    2310           1 : uart_report_port(struct uart_driver *drv, struct uart_port *port)
    2311             : {
    2312           1 :         char address[64];
    2313             : 
    2314           1 :         switch (port->iotype) {
    2315           1 :         case UPIO_PORT:
    2316           1 :                 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
    2317           1 :                 break;
    2318           0 :         case UPIO_HUB6:
    2319           0 :                 snprintf(address, sizeof(address),
    2320           0 :                          "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
    2321           0 :                 break;
    2322           0 :         case UPIO_MEM:
    2323             :         case UPIO_MEM16:
    2324             :         case UPIO_MEM32:
    2325             :         case UPIO_MEM32BE:
    2326             :         case UPIO_AU:
    2327             :         case UPIO_TSI:
    2328           0 :                 snprintf(address, sizeof(address),
    2329           0 :                          "MMIO 0x%llx", (unsigned long long)port->mapbase);
    2330           0 :                 break;
    2331           0 :         default:
    2332           0 :                 strlcpy(address, "*unknown*", sizeof(address));
    2333           0 :                 break;
    2334             :         }
    2335             : 
    2336           2 :         pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
    2337             :                port->dev ? dev_name(port->dev) : "",
    2338             :                port->dev ? ": " : "",
    2339             :                port->name,
    2340             :                address, port->irq, port->uartclk / 16, uart_type(port));
    2341           1 : }
    2342             : 
    2343             : static void
    2344           4 : uart_configure_port(struct uart_driver *drv, struct uart_state *state,
    2345             :                     struct uart_port *port)
    2346             : {
    2347           4 :         unsigned int flags;
    2348             : 
    2349             :         /*
    2350             :          * If there isn't a port here, don't do anything further.
    2351             :          */
    2352           4 :         if (!port->iobase && !port->mapbase && !port->membase)
    2353             :                 return;
    2354             : 
    2355             :         /*
    2356             :          * Now do the auto configuration stuff.  Note that config_port
    2357             :          * is expected to claim the resources and map the port for us.
    2358             :          */
    2359           4 :         flags = 0;
    2360           4 :         if (port->flags & UPF_AUTO_IRQ)
    2361           0 :                 flags |= UART_CONFIG_IRQ;
    2362           4 :         if (port->flags & UPF_BOOT_AUTOCONF) {
    2363           4 :                 if (!(port->flags & UPF_FIXED_TYPE)) {
    2364           4 :                         port->type = PORT_UNKNOWN;
    2365           4 :                         flags |= UART_CONFIG_TYPE;
    2366             :                 }
    2367           4 :                 port->ops->config_port(port, flags);
    2368             :         }
    2369             : 
    2370           4 :         if (port->type != PORT_UNKNOWN) {
    2371           1 :                 unsigned long flags;
    2372             : 
    2373           1 :                 uart_report_port(drv, port);
    2374             : 
    2375             :                 /* Power up port for set_mctrl() */
    2376           1 :                 uart_change_pm(state, UART_PM_STATE_ON);
    2377             : 
    2378             :                 /*
    2379             :                  * Ensure that the modem control lines are de-activated.
    2380             :                  * keep the DTR setting that is set in uart_set_options()
    2381             :                  * We probably don't need a spinlock around this, but
    2382             :                  */
    2383           1 :                 spin_lock_irqsave(&port->lock, flags);
    2384           1 :                 port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
    2385           1 :                 spin_unlock_irqrestore(&port->lock, flags);
    2386             : 
    2387             :                 /*
    2388             :                  * If this driver supports console, and it hasn't been
    2389             :                  * successfully registered yet, try to re-register it.
    2390             :                  * It may be that the port was not available.
    2391             :                  */
    2392           1 :                 if (port->cons && !(port->cons->flags & CON_ENABLED))
    2393           0 :                         register_console(port->cons);
    2394             : 
    2395             :                 /*
    2396             :                  * Power down all ports by default, except the
    2397             :                  * console if we have one.
    2398             :                  */
    2399           1 :                 if (!uart_console(port))
    2400           0 :                         uart_change_pm(state, UART_PM_STATE_OFF);
    2401             :         }
    2402             : }
    2403             : 
    2404             : #ifdef CONFIG_CONSOLE_POLL
    2405             : 
    2406             : static int uart_poll_init(struct tty_driver *driver, int line, char *options)
    2407             : {
    2408             :         struct uart_driver *drv = driver->driver_state;
    2409             :         struct uart_state *state = drv->state + line;
    2410             :         struct tty_port *tport;
    2411             :         struct uart_port *port;
    2412             :         int baud = 9600;
    2413             :         int bits = 8;
    2414             :         int parity = 'n';
    2415             :         int flow = 'n';
    2416             :         int ret = 0;
    2417             : 
    2418             :         tport = &state->port;
    2419             :         mutex_lock(&tport->mutex);
    2420             : 
    2421             :         port = uart_port_check(state);
    2422             :         if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
    2423             :                 ret = -1;
    2424             :                 goto out;
    2425             :         }
    2426             : 
    2427             :         if (port->ops->poll_init) {
    2428             :                 /*
    2429             :                  * We don't set initialized as we only initialized the hw,
    2430             :                  * e.g. state->xmit is still uninitialized.
    2431             :                  */
    2432             :                 if (!tty_port_initialized(tport))
    2433             :                         ret = port->ops->poll_init(port);
    2434             :         }
    2435             : 
    2436             :         if (!ret && options) {
    2437             :                 uart_parse_options(options, &baud, &parity, &bits, &flow);
    2438             :                 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
    2439             :         }
    2440             : out:
    2441             :         mutex_unlock(&tport->mutex);
    2442             :         return ret;
    2443             : }
    2444             : 
    2445             : static int uart_poll_get_char(struct tty_driver *driver, int line)
    2446             : {
    2447             :         struct uart_driver *drv = driver->driver_state;
    2448             :         struct uart_state *state = drv->state + line;
    2449             :         struct uart_port *port;
    2450             :         int ret = -1;
    2451             : 
    2452             :         port = uart_port_ref(state);
    2453             :         if (port) {
    2454             :                 ret = port->ops->poll_get_char(port);
    2455             :                 uart_port_deref(port);
    2456             :         }
    2457             : 
    2458             :         return ret;
    2459             : }
    2460             : 
    2461             : static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
    2462             : {
    2463             :         struct uart_driver *drv = driver->driver_state;
    2464             :         struct uart_state *state = drv->state + line;
    2465             :         struct uart_port *port;
    2466             : 
    2467             :         port = uart_port_ref(state);
    2468             :         if (!port)
    2469             :                 return;
    2470             : 
    2471             :         if (ch == '\n')
    2472             :                 port->ops->poll_put_char(port, '\r');
    2473             :         port->ops->poll_put_char(port, ch);
    2474             :         uart_port_deref(port);
    2475             : }
    2476             : #endif
    2477             : 
    2478             : static const struct tty_operations uart_ops = {
    2479             :         .install        = uart_install,
    2480             :         .open           = uart_open,
    2481             :         .close          = uart_close,
    2482             :         .write          = uart_write,
    2483             :         .put_char       = uart_put_char,
    2484             :         .flush_chars    = uart_flush_chars,
    2485             :         .write_room     = uart_write_room,
    2486             :         .chars_in_buffer= uart_chars_in_buffer,
    2487             :         .flush_buffer   = uart_flush_buffer,
    2488             :         .ioctl          = uart_ioctl,
    2489             :         .throttle       = uart_throttle,
    2490             :         .unthrottle     = uart_unthrottle,
    2491             :         .send_xchar     = uart_send_xchar,
    2492             :         .set_termios    = uart_set_termios,
    2493             :         .set_ldisc      = uart_set_ldisc,
    2494             :         .stop           = uart_stop,
    2495             :         .start          = uart_start,
    2496             :         .hangup         = uart_hangup,
    2497             :         .break_ctl      = uart_break_ctl,
    2498             :         .wait_until_sent= uart_wait_until_sent,
    2499             : #ifdef CONFIG_PROC_FS
    2500             :         .proc_show      = uart_proc_show,
    2501             : #endif
    2502             :         .tiocmget       = uart_tiocmget,
    2503             :         .tiocmset       = uart_tiocmset,
    2504             :         .set_serial     = uart_set_info_user,
    2505             :         .get_serial     = uart_get_info_user,
    2506             :         .get_icount     = uart_get_icount,
    2507             : #ifdef CONFIG_CONSOLE_POLL
    2508             :         .poll_init      = uart_poll_init,
    2509             :         .poll_get_char  = uart_poll_get_char,
    2510             :         .poll_put_char  = uart_poll_put_char,
    2511             : #endif
    2512             : };
    2513             : 
    2514             : static const struct tty_port_operations uart_port_ops = {
    2515             :         .carrier_raised = uart_carrier_raised,
    2516             :         .dtr_rts        = uart_dtr_rts,
    2517             :         .activate       = uart_port_activate,
    2518             :         .shutdown       = uart_tty_port_shutdown,
    2519             : };
    2520             : 
    2521             : /**
    2522             :  *      uart_register_driver - register a driver with the uart core layer
    2523             :  *      @drv: low level driver structure
    2524             :  *
    2525             :  *      Register a uart driver with the core driver.  We in turn register
    2526             :  *      with the tty layer, and initialise the core driver per-port state.
    2527             :  *
    2528             :  *      We have a proc file in /proc/tty/driver which is named after the
    2529             :  *      normal driver.
    2530             :  *
    2531             :  *      drv->port should be NULL, and the per-port structures should be
    2532             :  *      registered using uart_add_one_port after this call has succeeded.
    2533             :  */
    2534           1 : int uart_register_driver(struct uart_driver *drv)
    2535             : {
    2536           1 :         struct tty_driver *normal;
    2537           1 :         int i, retval = -ENOMEM;
    2538             : 
    2539           1 :         BUG_ON(drv->state);
    2540             : 
    2541             :         /*
    2542             :          * Maybe we should be using a slab cache for this, especially if
    2543             :          * we have a large number of ports to handle.
    2544             :          */
    2545           1 :         drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
    2546           1 :         if (!drv->state)
    2547           0 :                 goto out;
    2548             : 
    2549           1 :         normal = alloc_tty_driver(drv->nr);
    2550           1 :         if (!normal)
    2551           0 :                 goto out_kfree;
    2552             : 
    2553           1 :         drv->tty_driver = normal;
    2554             : 
    2555           1 :         normal->driver_name  = drv->driver_name;
    2556           1 :         normal->name         = drv->dev_name;
    2557           1 :         normal->major                = drv->major;
    2558           1 :         normal->minor_start  = drv->minor;
    2559           1 :         normal->type         = TTY_DRIVER_TYPE_SERIAL;
    2560           1 :         normal->subtype              = SERIAL_TYPE_NORMAL;
    2561           1 :         normal->init_termios = tty_std_termios;
    2562           1 :         normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
    2563           1 :         normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
    2564           1 :         normal->flags                = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
    2565           1 :         normal->driver_state    = drv;
    2566           1 :         tty_set_operations(normal, &uart_ops);
    2567             : 
    2568             :         /*
    2569             :          * Initialise the UART state(s).
    2570             :          */
    2571           6 :         for (i = 0; i < drv->nr; i++) {
    2572           4 :                 struct uart_state *state = drv->state + i;
    2573           4 :                 struct tty_port *port = &state->port;
    2574             : 
    2575           4 :                 tty_port_init(port);
    2576           4 :                 port->ops = &uart_port_ops;
    2577             :         }
    2578             : 
    2579           1 :         retval = tty_register_driver(normal);
    2580           1 :         if (retval >= 0)
    2581             :                 return retval;
    2582             : 
    2583           0 :         for (i = 0; i < drv->nr; i++)
    2584           0 :                 tty_port_destroy(&drv->state[i].port);
    2585           0 :         put_tty_driver(normal);
    2586           0 : out_kfree:
    2587           0 :         kfree(drv->state);
    2588             : out:
    2589             :         return retval;
    2590             : }
    2591             : 
    2592             : /**
    2593             :  *      uart_unregister_driver - remove a driver from the uart core layer
    2594             :  *      @drv: low level driver structure
    2595             :  *
    2596             :  *      Remove all references to a driver from the core driver.  The low
    2597             :  *      level driver must have removed all its ports via the
    2598             :  *      uart_remove_one_port() if it registered them with uart_add_one_port().
    2599             :  *      (ie, drv->port == NULL)
    2600             :  */
    2601           0 : void uart_unregister_driver(struct uart_driver *drv)
    2602             : {
    2603           0 :         struct tty_driver *p = drv->tty_driver;
    2604           0 :         unsigned int i;
    2605             : 
    2606           0 :         tty_unregister_driver(p);
    2607           0 :         put_tty_driver(p);
    2608           0 :         for (i = 0; i < drv->nr; i++)
    2609           0 :                 tty_port_destroy(&drv->state[i].port);
    2610           0 :         kfree(drv->state);
    2611           0 :         drv->state = NULL;
    2612           0 :         drv->tty_driver = NULL;
    2613           0 : }
    2614             : 
    2615         137 : struct tty_driver *uart_console_device(struct console *co, int *index)
    2616             : {
    2617         137 :         struct uart_driver *p = co->data;
    2618         137 :         *index = co->index;
    2619         137 :         return p->tty_driver;
    2620             : }
    2621             : EXPORT_SYMBOL_GPL(uart_console_device);
    2622             : 
    2623           0 : static ssize_t uartclk_show(struct device *dev,
    2624             :         struct device_attribute *attr, char *buf)
    2625             : {
    2626           0 :         struct serial_struct tmp;
    2627           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2628             : 
    2629           0 :         uart_get_info(port, &tmp);
    2630           0 :         return sprintf(buf, "%d\n", tmp.baud_base * 16);
    2631             : }
    2632             : 
    2633           0 : static ssize_t type_show(struct device *dev,
    2634             :         struct device_attribute *attr, char *buf)
    2635             : {
    2636           0 :         struct serial_struct tmp;
    2637           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2638             : 
    2639           0 :         uart_get_info(port, &tmp);
    2640           0 :         return sprintf(buf, "%d\n", tmp.type);
    2641             : }
    2642             : 
    2643           0 : static ssize_t line_show(struct device *dev,
    2644             :         struct device_attribute *attr, char *buf)
    2645             : {
    2646           0 :         struct serial_struct tmp;
    2647           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2648             : 
    2649           0 :         uart_get_info(port, &tmp);
    2650           0 :         return sprintf(buf, "%d\n", tmp.line);
    2651             : }
    2652             : 
    2653           0 : static ssize_t port_show(struct device *dev,
    2654             :         struct device_attribute *attr, char *buf)
    2655             : {
    2656           0 :         struct serial_struct tmp;
    2657           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2658           0 :         unsigned long ioaddr;
    2659             : 
    2660           0 :         uart_get_info(port, &tmp);
    2661           0 :         ioaddr = tmp.port;
    2662           0 :         if (HIGH_BITS_OFFSET)
    2663           0 :                 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
    2664           0 :         return sprintf(buf, "0x%lX\n", ioaddr);
    2665             : }
    2666             : 
    2667           0 : static ssize_t irq_show(struct device *dev,
    2668             :         struct device_attribute *attr, char *buf)
    2669             : {
    2670           0 :         struct serial_struct tmp;
    2671           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2672             : 
    2673           0 :         uart_get_info(port, &tmp);
    2674           0 :         return sprintf(buf, "%d\n", tmp.irq);
    2675             : }
    2676             : 
    2677           0 : static ssize_t flags_show(struct device *dev,
    2678             :         struct device_attribute *attr, char *buf)
    2679             : {
    2680           0 :         struct serial_struct tmp;
    2681           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2682             : 
    2683           0 :         uart_get_info(port, &tmp);
    2684           0 :         return sprintf(buf, "0x%X\n", tmp.flags);
    2685             : }
    2686             : 
    2687           0 : static ssize_t xmit_fifo_size_show(struct device *dev,
    2688             :         struct device_attribute *attr, char *buf)
    2689             : {
    2690           0 :         struct serial_struct tmp;
    2691           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2692             : 
    2693           0 :         uart_get_info(port, &tmp);
    2694           0 :         return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
    2695             : }
    2696             : 
    2697           0 : static ssize_t close_delay_show(struct device *dev,
    2698             :         struct device_attribute *attr, char *buf)
    2699             : {
    2700           0 :         struct serial_struct tmp;
    2701           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2702             : 
    2703           0 :         uart_get_info(port, &tmp);
    2704           0 :         return sprintf(buf, "%d\n", tmp.close_delay);
    2705             : }
    2706             : 
    2707           0 : static ssize_t closing_wait_show(struct device *dev,
    2708             :         struct device_attribute *attr, char *buf)
    2709             : {
    2710           0 :         struct serial_struct tmp;
    2711           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2712             : 
    2713           0 :         uart_get_info(port, &tmp);
    2714           0 :         return sprintf(buf, "%d\n", tmp.closing_wait);
    2715             : }
    2716             : 
    2717           0 : static ssize_t custom_divisor_show(struct device *dev,
    2718             :         struct device_attribute *attr, char *buf)
    2719             : {
    2720           0 :         struct serial_struct tmp;
    2721           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2722             : 
    2723           0 :         uart_get_info(port, &tmp);
    2724           0 :         return sprintf(buf, "%d\n", tmp.custom_divisor);
    2725             : }
    2726             : 
    2727           0 : static ssize_t io_type_show(struct device *dev,
    2728             :         struct device_attribute *attr, char *buf)
    2729             : {
    2730           0 :         struct serial_struct tmp;
    2731           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2732             : 
    2733           0 :         uart_get_info(port, &tmp);
    2734           0 :         return sprintf(buf, "%d\n", tmp.io_type);
    2735             : }
    2736             : 
    2737           0 : static ssize_t iomem_base_show(struct device *dev,
    2738             :         struct device_attribute *attr, char *buf)
    2739             : {
    2740           0 :         struct serial_struct tmp;
    2741           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2742             : 
    2743           0 :         uart_get_info(port, &tmp);
    2744           0 :         return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
    2745             : }
    2746             : 
    2747           0 : static ssize_t iomem_reg_shift_show(struct device *dev,
    2748             :         struct device_attribute *attr, char *buf)
    2749             : {
    2750           0 :         struct serial_struct tmp;
    2751           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2752             : 
    2753           0 :         uart_get_info(port, &tmp);
    2754           0 :         return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
    2755             : }
    2756             : 
    2757           0 : static ssize_t console_show(struct device *dev,
    2758             :         struct device_attribute *attr, char *buf)
    2759             : {
    2760           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2761           0 :         struct uart_state *state = container_of(port, struct uart_state, port);
    2762           0 :         struct uart_port *uport;
    2763           0 :         bool console = false;
    2764             : 
    2765           0 :         mutex_lock(&port->mutex);
    2766           0 :         uport = uart_port_check(state);
    2767           0 :         if (uport)
    2768           0 :                 console = uart_console_enabled(uport);
    2769           0 :         mutex_unlock(&port->mutex);
    2770             : 
    2771           0 :         return sprintf(buf, "%c\n", console ? 'Y' : 'N');
    2772             : }
    2773             : 
    2774           0 : static ssize_t console_store(struct device *dev,
    2775             :         struct device_attribute *attr, const char *buf, size_t count)
    2776             : {
    2777           0 :         struct tty_port *port = dev_get_drvdata(dev);
    2778           0 :         struct uart_state *state = container_of(port, struct uart_state, port);
    2779           0 :         struct uart_port *uport;
    2780           0 :         bool oldconsole, newconsole;
    2781           0 :         int ret;
    2782             : 
    2783           0 :         ret = kstrtobool(buf, &newconsole);
    2784           0 :         if (ret)
    2785           0 :                 return ret;
    2786             : 
    2787           0 :         mutex_lock(&port->mutex);
    2788           0 :         uport = uart_port_check(state);
    2789           0 :         if (uport) {
    2790           0 :                 oldconsole = uart_console_enabled(uport);
    2791           0 :                 if (oldconsole && !newconsole) {
    2792           0 :                         ret = unregister_console(uport->cons);
    2793           0 :                 } else if (!oldconsole && newconsole) {
    2794           0 :                         if (uart_console(uport)) {
    2795           0 :                                 uport->console_reinit = 1;
    2796           0 :                                 register_console(uport->cons);
    2797             :                         } else {
    2798             :                                 ret = -ENOENT;
    2799             :                         }
    2800             :                 }
    2801             :         } else {
    2802             :                 ret = -ENXIO;
    2803             :         }
    2804           0 :         mutex_unlock(&port->mutex);
    2805             : 
    2806           0 :         return ret < 0 ? ret : count;
    2807             : }
    2808             : 
    2809             : static DEVICE_ATTR_RO(uartclk);
    2810             : static DEVICE_ATTR_RO(type);
    2811             : static DEVICE_ATTR_RO(line);
    2812             : static DEVICE_ATTR_RO(port);
    2813             : static DEVICE_ATTR_RO(irq);
    2814             : static DEVICE_ATTR_RO(flags);
    2815             : static DEVICE_ATTR_RO(xmit_fifo_size);
    2816             : static DEVICE_ATTR_RO(close_delay);
    2817             : static DEVICE_ATTR_RO(closing_wait);
    2818             : static DEVICE_ATTR_RO(custom_divisor);
    2819             : static DEVICE_ATTR_RO(io_type);
    2820             : static DEVICE_ATTR_RO(iomem_base);
    2821             : static DEVICE_ATTR_RO(iomem_reg_shift);
    2822             : static DEVICE_ATTR_RW(console);
    2823             : 
    2824             : static struct attribute *tty_dev_attrs[] = {
    2825             :         &dev_attr_uartclk.attr,
    2826             :         &dev_attr_type.attr,
    2827             :         &dev_attr_line.attr,
    2828             :         &dev_attr_port.attr,
    2829             :         &dev_attr_irq.attr,
    2830             :         &dev_attr_flags.attr,
    2831             :         &dev_attr_xmit_fifo_size.attr,
    2832             :         &dev_attr_close_delay.attr,
    2833             :         &dev_attr_closing_wait.attr,
    2834             :         &dev_attr_custom_divisor.attr,
    2835             :         &dev_attr_io_type.attr,
    2836             :         &dev_attr_iomem_base.attr,
    2837             :         &dev_attr_iomem_reg_shift.attr,
    2838             :         &dev_attr_console.attr,
    2839             :         NULL
    2840             : };
    2841             : 
    2842             : static const struct attribute_group tty_dev_attr_group = {
    2843             :         .attrs = tty_dev_attrs,
    2844             : };
    2845             : 
    2846             : /**
    2847             :  *      uart_add_one_port - attach a driver-defined port structure
    2848             :  *      @drv: pointer to the uart low level driver structure for this port
    2849             :  *      @uport: uart port structure to use for this port.
    2850             :  *
    2851             :  *      Context: task context, might sleep
    2852             :  *
    2853             :  *      This allows the driver to register its own uart_port structure
    2854             :  *      with the core driver.  The main purpose is to allow the low
    2855             :  *      level uart drivers to expand uart_port, rather than having yet
    2856             :  *      more levels of structures.
    2857             :  */
    2858           4 : int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
    2859             : {
    2860           4 :         struct uart_state *state;
    2861           4 :         struct tty_port *port;
    2862           4 :         int ret = 0;
    2863           4 :         struct device *tty_dev;
    2864           4 :         int num_groups;
    2865             : 
    2866           4 :         if (uport->line >= drv->nr)
    2867             :                 return -EINVAL;
    2868             : 
    2869           4 :         state = drv->state + uport->line;
    2870           4 :         port = &state->port;
    2871             : 
    2872           4 :         mutex_lock(&port_mutex);
    2873           4 :         mutex_lock(&port->mutex);
    2874           4 :         if (state->uart_port) {
    2875           0 :                 ret = -EINVAL;
    2876           0 :                 goto out;
    2877             :         }
    2878             : 
    2879             :         /* Link the port to the driver state table and vice versa */
    2880           4 :         atomic_set(&state->refcount, 1);
    2881           4 :         init_waitqueue_head(&state->remove_wait);
    2882           4 :         state->uart_port = uport;
    2883           4 :         uport->state = state;
    2884             : 
    2885           4 :         state->pm_state = UART_PM_STATE_UNDEFINED;
    2886           4 :         uport->cons = drv->cons;
    2887           4 :         uport->minor = drv->tty_driver->minor_start + uport->line;
    2888           8 :         uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
    2889           4 :                                 drv->tty_driver->name_base + uport->line);
    2890           4 :         if (!uport->name) {
    2891           0 :                 ret = -ENOMEM;
    2892           0 :                 goto out;
    2893             :         }
    2894             : 
    2895             :         /*
    2896             :          * If this port is in use as a console then the spinlock is already
    2897             :          * initialised.
    2898             :          */
    2899           4 :         if (!uart_console_enabled(uport))
    2900           3 :                 uart_port_spin_lock_init(uport);
    2901             : 
    2902           4 :         if (uport->cons && uport->dev)
    2903           4 :                 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
    2904             : 
    2905           4 :         tty_port_link_device(port, drv->tty_driver, uport->line);
    2906           4 :         uart_configure_port(drv, state, uport);
    2907             : 
    2908           4 :         port->console = uart_console(uport);
    2909             : 
    2910           4 :         num_groups = 2;
    2911           4 :         if (uport->attr_group)
    2912           1 :                 num_groups++;
    2913             : 
    2914           4 :         uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
    2915             :                                     GFP_KERNEL);
    2916           4 :         if (!uport->tty_groups) {
    2917           0 :                 ret = -ENOMEM;
    2918           0 :                 goto out;
    2919             :         }
    2920           4 :         uport->tty_groups[0] = &tty_dev_attr_group;
    2921           4 :         if (uport->attr_group)
    2922           1 :                 uport->tty_groups[1] = uport->attr_group;
    2923             : 
    2924             :         /*
    2925             :          * Register the port whether it's detected or not.  This allows
    2926             :          * setserial to be used to alter this port's parameters.
    2927             :          */
    2928           4 :         tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
    2929             :                         uport->line, uport->dev, port, uport->tty_groups);
    2930           4 :         if (!IS_ERR(tty_dev)) {
    2931           4 :                 device_set_wakeup_capable(tty_dev, 1);
    2932             :         } else {
    2933           0 :                 dev_err(uport->dev, "Cannot register tty device on line %d\n",
    2934             :                        uport->line);
    2935             :         }
    2936             : 
    2937             :         /*
    2938             :          * Ensure UPF_DEAD is not set.
    2939             :          */
    2940           4 :         uport->flags &= ~UPF_DEAD;
    2941             : 
    2942           4 :  out:
    2943           4 :         mutex_unlock(&port->mutex);
    2944           4 :         mutex_unlock(&port_mutex);
    2945             : 
    2946           4 :         return ret;
    2947             : }
    2948             : 
    2949             : /**
    2950             :  *      uart_remove_one_port - detach a driver defined port structure
    2951             :  *      @drv: pointer to the uart low level driver structure for this port
    2952             :  *      @uport: uart port structure for this port
    2953             :  *
    2954             :  *      Context: task context, might sleep
    2955             :  *
    2956             :  *      This unhooks (and hangs up) the specified port structure from the
    2957             :  *      core driver.  No further calls will be made to the low-level code
    2958             :  *      for this port.
    2959             :  */
    2960           0 : int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
    2961             : {
    2962           0 :         struct uart_state *state = drv->state + uport->line;
    2963           0 :         struct tty_port *port = &state->port;
    2964           0 :         struct uart_port *uart_port;
    2965           0 :         struct tty_struct *tty;
    2966           0 :         int ret = 0;
    2967             : 
    2968           0 :         mutex_lock(&port_mutex);
    2969             : 
    2970             :         /*
    2971             :          * Mark the port "dead" - this prevents any opens from
    2972             :          * succeeding while we shut down the port.
    2973             :          */
    2974           0 :         mutex_lock(&port->mutex);
    2975           0 :         uart_port = uart_port_check(state);
    2976           0 :         if (uart_port != uport)
    2977           0 :                 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
    2978             :                           uart_port, uport);
    2979             : 
    2980           0 :         if (!uart_port) {
    2981           0 :                 mutex_unlock(&port->mutex);
    2982           0 :                 ret = -EINVAL;
    2983           0 :                 goto out;
    2984             :         }
    2985           0 :         uport->flags |= UPF_DEAD;
    2986           0 :         mutex_unlock(&port->mutex);
    2987             : 
    2988             :         /*
    2989             :          * Remove the devices from the tty layer
    2990             :          */
    2991           0 :         tty_port_unregister_device(port, drv->tty_driver, uport->line);
    2992             : 
    2993           0 :         tty = tty_port_tty_get(port);
    2994           0 :         if (tty) {
    2995           0 :                 tty_vhangup(port->tty);
    2996           0 :                 tty_kref_put(tty);
    2997             :         }
    2998             : 
    2999             :         /*
    3000             :          * If the port is used as a console, unregister it
    3001             :          */
    3002           0 :         if (uart_console(uport))
    3003           0 :                 unregister_console(uport->cons);
    3004             : 
    3005             :         /*
    3006             :          * Free the port IO and memory resources, if any.
    3007             :          */
    3008           0 :         if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
    3009           0 :                 uport->ops->release_port(uport);
    3010           0 :         kfree(uport->tty_groups);
    3011           0 :         kfree(uport->name);
    3012             : 
    3013             :         /*
    3014             :          * Indicate that there isn't a port here anymore.
    3015             :          */
    3016           0 :         uport->type = PORT_UNKNOWN;
    3017             : 
    3018           0 :         mutex_lock(&port->mutex);
    3019           0 :         WARN_ON(atomic_dec_return(&state->refcount) < 0);
    3020           0 :         wait_event(state->remove_wait, !atomic_read(&state->refcount));
    3021           0 :         state->uart_port = NULL;
    3022           0 :         mutex_unlock(&port->mutex);
    3023           0 : out:
    3024           0 :         mutex_unlock(&port_mutex);
    3025             : 
    3026           0 :         return ret;
    3027             : }
    3028             : 
    3029             : /*
    3030             :  *      Are the two ports equivalent?
    3031             :  */
    3032           0 : int uart_match_port(struct uart_port *port1, struct uart_port *port2)
    3033             : {
    3034           0 :         if (port1->iotype != port2->iotype)
    3035             :                 return 0;
    3036             : 
    3037           0 :         switch (port1->iotype) {
    3038           0 :         case UPIO_PORT:
    3039           0 :                 return (port1->iobase == port2->iobase);
    3040           0 :         case UPIO_HUB6:
    3041           0 :                 return (port1->iobase == port2->iobase) &&
    3042           0 :                        (port1->hub6   == port2->hub6);
    3043           0 :         case UPIO_MEM:
    3044             :         case UPIO_MEM16:
    3045             :         case UPIO_MEM32:
    3046             :         case UPIO_MEM32BE:
    3047             :         case UPIO_AU:
    3048             :         case UPIO_TSI:
    3049           0 :                 return (port1->mapbase == port2->mapbase);
    3050             :         }
    3051             :         return 0;
    3052             : }
    3053             : EXPORT_SYMBOL(uart_match_port);
    3054             : 
    3055             : /**
    3056             :  *      uart_handle_dcd_change - handle a change of carrier detect state
    3057             :  *      @uport: uart_port structure for the open port
    3058             :  *      @status: new carrier detect status, nonzero if active
    3059             :  *
    3060             :  *      Caller must hold uport->lock
    3061             :  */
    3062           0 : void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
    3063             : {
    3064           0 :         struct tty_port *port = &uport->state->port;
    3065           0 :         struct tty_struct *tty = port->tty;
    3066           0 :         struct tty_ldisc *ld;
    3067             : 
    3068           0 :         lockdep_assert_held_once(&uport->lock);
    3069             : 
    3070           0 :         if (tty) {
    3071           0 :                 ld = tty_ldisc_ref(tty);
    3072           0 :                 if (ld) {
    3073           0 :                         if (ld->ops->dcd_change)
    3074           0 :                                 ld->ops->dcd_change(tty, status);
    3075           0 :                         tty_ldisc_deref(ld);
    3076             :                 }
    3077             :         }
    3078             : 
    3079           0 :         uport->icount.dcd++;
    3080             : 
    3081           0 :         if (uart_dcd_enabled(uport)) {
    3082           0 :                 if (status)
    3083           0 :                         wake_up_interruptible(&port->open_wait);
    3084           0 :                 else if (tty)
    3085           0 :                         tty_hangup(tty);
    3086             :         }
    3087           0 : }
    3088             : EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
    3089             : 
    3090             : /**
    3091             :  *      uart_handle_cts_change - handle a change of clear-to-send state
    3092             :  *      @uport: uart_port structure for the open port
    3093             :  *      @status: new clear to send status, nonzero if active
    3094             :  *
    3095             :  *      Caller must hold uport->lock
    3096             :  */
    3097           0 : void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
    3098             : {
    3099           0 :         lockdep_assert_held_once(&uport->lock);
    3100             : 
    3101           0 :         uport->icount.cts++;
    3102             : 
    3103           0 :         if (uart_softcts_mode(uport)) {
    3104           0 :                 if (uport->hw_stopped) {
    3105           0 :                         if (status) {
    3106           0 :                                 uport->hw_stopped = 0;
    3107           0 :                                 uport->ops->start_tx(uport);
    3108           0 :                                 uart_write_wakeup(uport);
    3109             :                         }
    3110             :                 } else {
    3111           0 :                         if (!status) {
    3112           0 :                                 uport->hw_stopped = 1;
    3113           0 :                                 uport->ops->stop_tx(uport);
    3114             :                         }
    3115             :                 }
    3116             : 
    3117             :         }
    3118           0 : }
    3119             : EXPORT_SYMBOL_GPL(uart_handle_cts_change);
    3120             : 
    3121             : /**
    3122             :  * uart_insert_char - push a char to the uart layer
    3123             :  *
    3124             :  * User is responsible to call tty_flip_buffer_push when they are done with
    3125             :  * insertion.
    3126             :  *
    3127             :  * @port: corresponding port
    3128             :  * @status: state of the serial port RX buffer (LSR for 8250)
    3129             :  * @overrun: mask of overrun bits in @status
    3130             :  * @ch: character to push
    3131             :  * @flag: flag for the character (see TTY_NORMAL and friends)
    3132             :  */
    3133           0 : void uart_insert_char(struct uart_port *port, unsigned int status,
    3134             :                  unsigned int overrun, unsigned int ch, unsigned int flag)
    3135             : {
    3136           0 :         struct tty_port *tport = &port->state->port;
    3137             : 
    3138           0 :         if ((status & port->ignore_status_mask & ~overrun) == 0)
    3139           0 :                 if (tty_insert_flip_char(tport, ch, flag) == 0)
    3140           0 :                         ++port->icount.buf_overrun;
    3141             : 
    3142             :         /*
    3143             :          * Overrun is special.  Since it's reported immediately,
    3144             :          * it doesn't affect the current character.
    3145             :          */
    3146           0 :         if (status & ~port->ignore_status_mask & overrun)
    3147           0 :                 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
    3148           0 :                         ++port->icount.buf_overrun;
    3149           0 : }
    3150             : EXPORT_SYMBOL_GPL(uart_insert_char);
    3151             : 
    3152             : #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
    3153             : static const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
    3154             : 
    3155             : static void uart_sysrq_on(struct work_struct *w)
    3156             : {
    3157             :         int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
    3158             : 
    3159             :         sysrq_toggle_support(1);
    3160             :         pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
    3161             :                 sysrq_toggle_seq_len, sysrq_toggle_seq);
    3162             : }
    3163             : static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
    3164             : 
    3165             : /**
    3166             :  *      uart_try_toggle_sysrq - Enables SysRq from serial line
    3167             :  *      @port: uart_port structure where char(s) after BREAK met
    3168             :  *      @ch: new character in the sequence after received BREAK
    3169             :  *
    3170             :  *      Enables magic SysRq when the required sequence is met on port
    3171             :  *      (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
    3172             :  *
    3173             :  *      Returns false if @ch is out of enabling sequence and should be
    3174             :  *      handled some other way, true if @ch was consumed.
    3175             :  */
    3176             : bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
    3177             : {
    3178             :         int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
    3179             : 
    3180             :         if (!sysrq_toggle_seq_len)
    3181             :                 return false;
    3182             : 
    3183             :         BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
    3184             :         if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
    3185             :                 port->sysrq_seq = 0;
    3186             :                 return false;
    3187             :         }
    3188             : 
    3189             :         if (++port->sysrq_seq < sysrq_toggle_seq_len) {
    3190             :                 port->sysrq = jiffies + SYSRQ_TIMEOUT;
    3191             :                 return true;
    3192             :         }
    3193             : 
    3194             :         schedule_work(&sysrq_enable_work);
    3195             : 
    3196             :         port->sysrq = 0;
    3197             :         return true;
    3198             : }
    3199             : EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
    3200             : #endif
    3201             : 
    3202             : EXPORT_SYMBOL(uart_write_wakeup);
    3203             : EXPORT_SYMBOL(uart_register_driver);
    3204             : EXPORT_SYMBOL(uart_unregister_driver);
    3205             : EXPORT_SYMBOL(uart_suspend_port);
    3206             : EXPORT_SYMBOL(uart_resume_port);
    3207             : EXPORT_SYMBOL(uart_add_one_port);
    3208             : EXPORT_SYMBOL(uart_remove_one_port);
    3209             : 
    3210             : /**
    3211             :  * uart_get_rs485_mode() - retrieve rs485 properties for given uart
    3212             :  * @port: uart device's target port
    3213             :  *
    3214             :  * This function implements the device tree binding described in
    3215             :  * Documentation/devicetree/bindings/serial/rs485.txt.
    3216             :  */
    3217           0 : int uart_get_rs485_mode(struct uart_port *port)
    3218             : {
    3219           0 :         struct serial_rs485 *rs485conf = &port->rs485;
    3220           0 :         struct device *dev = port->dev;
    3221           0 :         u32 rs485_delay[2];
    3222           0 :         int ret;
    3223             : 
    3224           0 :         ret = device_property_read_u32_array(dev, "rs485-rts-delay",
    3225             :                                              rs485_delay, 2);
    3226           0 :         if (!ret) {
    3227           0 :                 rs485conf->delay_rts_before_send = rs485_delay[0];
    3228           0 :                 rs485conf->delay_rts_after_send = rs485_delay[1];
    3229             :         } else {
    3230           0 :                 rs485conf->delay_rts_before_send = 0;
    3231           0 :                 rs485conf->delay_rts_after_send = 0;
    3232             :         }
    3233             : 
    3234             :         /*
    3235             :          * Clear full-duplex and enabled flags, set RTS polarity to active high
    3236             :          * to get to a defined state with the following properties:
    3237             :          */
    3238           0 :         rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
    3239             :                               SER_RS485_TERMINATE_BUS |
    3240             :                               SER_RS485_RTS_AFTER_SEND);
    3241           0 :         rs485conf->flags |= SER_RS485_RTS_ON_SEND;
    3242             : 
    3243           0 :         if (device_property_read_bool(dev, "rs485-rx-during-tx"))
    3244           0 :                 rs485conf->flags |= SER_RS485_RX_DURING_TX;
    3245             : 
    3246           0 :         if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
    3247           0 :                 rs485conf->flags |= SER_RS485_ENABLED;
    3248             : 
    3249           0 :         if (device_property_read_bool(dev, "rs485-rts-active-low")) {
    3250           0 :                 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
    3251           0 :                 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
    3252             :         }
    3253             : 
    3254             :         /*
    3255             :          * Disabling termination by default is the safe choice:  Else if many
    3256             :          * bus participants enable it, no communication is possible at all.
    3257             :          * Works fine for short cables and users may enable for longer cables.
    3258             :          */
    3259           0 :         port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
    3260             :                                                         GPIOD_OUT_LOW);
    3261           0 :         if (IS_ERR(port->rs485_term_gpio)) {
    3262             :                 ret = PTR_ERR(port->rs485_term_gpio);
    3263             :                 port->rs485_term_gpio = NULL;
    3264             :                 return dev_err_probe(dev, ret, "Cannot get rs485-term-gpios\n");
    3265             :         }
    3266             : 
    3267             :         return 0;
    3268             : }
    3269             : EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
    3270             : 
    3271             : MODULE_DESCRIPTION("Serial driver core");
    3272             : MODULE_LICENSE("GPL");

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