LCOV - code coverage report
Current view: top level - include/linux - serial_core.h (source / functions) Hit Total Coverage
Test: landlock.info Lines: 13 26 50.0 %
Date: 2021-04-22 12:43:58 Functions: 1 2 50.0 %

          Line data    Source code
       1             : /* SPDX-License-Identifier: GPL-2.0-or-later */
       2             : /*
       3             :  *  linux/drivers/char/serial_core.h
       4             :  *
       5             :  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
       6             :  */
       7             : #ifndef LINUX_SERIAL_CORE_H
       8             : #define LINUX_SERIAL_CORE_H
       9             : 
      10             : #include <linux/bitops.h>
      11             : #include <linux/compiler.h>
      12             : #include <linux/console.h>
      13             : #include <linux/interrupt.h>
      14             : #include <linux/circ_buf.h>
      15             : #include <linux/spinlock.h>
      16             : #include <linux/sched.h>
      17             : #include <linux/tty.h>
      18             : #include <linux/mutex.h>
      19             : #include <linux/sysrq.h>
      20             : #include <uapi/linux/serial_core.h>
      21             : 
      22             : #ifdef CONFIG_SERIAL_CORE_CONSOLE
      23             : #define uart_console(port) \
      24             :         ((port)->cons && (port)->cons->index == (port)->line)
      25             : #else
      26             : #define uart_console(port)      ({ (void)port; 0; })
      27             : #endif
      28             : 
      29             : struct uart_port;
      30             : struct serial_struct;
      31             : struct device;
      32             : struct gpio_desc;
      33             : 
      34             : /*
      35             :  * This structure describes all the operations that can be done on the
      36             :  * physical hardware.  See Documentation/driver-api/serial/driver.rst for details.
      37             :  */
      38             : struct uart_ops {
      39             :         unsigned int    (*tx_empty)(struct uart_port *);
      40             :         void            (*set_mctrl)(struct uart_port *, unsigned int mctrl);
      41             :         unsigned int    (*get_mctrl)(struct uart_port *);
      42             :         void            (*stop_tx)(struct uart_port *);
      43             :         void            (*start_tx)(struct uart_port *);
      44             :         void            (*throttle)(struct uart_port *);
      45             :         void            (*unthrottle)(struct uart_port *);
      46             :         void            (*send_xchar)(struct uart_port *, char ch);
      47             :         void            (*stop_rx)(struct uart_port *);
      48             :         void            (*enable_ms)(struct uart_port *);
      49             :         void            (*break_ctl)(struct uart_port *, int ctl);
      50             :         int             (*startup)(struct uart_port *);
      51             :         void            (*shutdown)(struct uart_port *);
      52             :         void            (*flush_buffer)(struct uart_port *);
      53             :         void            (*set_termios)(struct uart_port *, struct ktermios *new,
      54             :                                        struct ktermios *old);
      55             :         void            (*set_ldisc)(struct uart_port *, struct ktermios *);
      56             :         void            (*pm)(struct uart_port *, unsigned int state,
      57             :                               unsigned int oldstate);
      58             : 
      59             :         /*
      60             :          * Return a string describing the type of the port
      61             :          */
      62             :         const char      *(*type)(struct uart_port *);
      63             : 
      64             :         /*
      65             :          * Release IO and memory resources used by the port.
      66             :          * This includes iounmap if necessary.
      67             :          */
      68             :         void            (*release_port)(struct uart_port *);
      69             : 
      70             :         /*
      71             :          * Request IO and memory resources used by the port.
      72             :          * This includes iomapping the port if necessary.
      73             :          */
      74             :         int             (*request_port)(struct uart_port *);
      75             :         void            (*config_port)(struct uart_port *, int);
      76             :         int             (*verify_port)(struct uart_port *, struct serial_struct *);
      77             :         int             (*ioctl)(struct uart_port *, unsigned int, unsigned long);
      78             : #ifdef CONFIG_CONSOLE_POLL
      79             :         int             (*poll_init)(struct uart_port *);
      80             :         void            (*poll_put_char)(struct uart_port *, unsigned char);
      81             :         int             (*poll_get_char)(struct uart_port *);
      82             : #endif
      83             : };
      84             : 
      85             : #define NO_POLL_CHAR            0x00ff0000
      86             : #define UART_CONFIG_TYPE        (1 << 0)
      87             : #define UART_CONFIG_IRQ         (1 << 1)
      88             : 
      89             : struct uart_icount {
      90             :         __u32   cts;
      91             :         __u32   dsr;
      92             :         __u32   rng;
      93             :         __u32   dcd;
      94             :         __u32   rx;
      95             :         __u32   tx;
      96             :         __u32   frame;
      97             :         __u32   overrun;
      98             :         __u32   parity;
      99             :         __u32   brk;
     100             :         __u32   buf_overrun;
     101             : };
     102             : 
     103             : typedef unsigned int __bitwise upf_t;
     104             : typedef unsigned int __bitwise upstat_t;
     105             : 
     106             : struct uart_port {
     107             :         spinlock_t              lock;                   /* port lock */
     108             :         unsigned long           iobase;                 /* in/out[bwl] */
     109             :         unsigned char __iomem   *membase;               /* read/write[bwl] */
     110             :         unsigned int            (*serial_in)(struct uart_port *, int);
     111             :         void                    (*serial_out)(struct uart_port *, int, int);
     112             :         void                    (*set_termios)(struct uart_port *,
     113             :                                                struct ktermios *new,
     114             :                                                struct ktermios *old);
     115             :         void                    (*set_ldisc)(struct uart_port *,
     116             :                                              struct ktermios *);
     117             :         unsigned int            (*get_mctrl)(struct uart_port *);
     118             :         void                    (*set_mctrl)(struct uart_port *, unsigned int);
     119             :         unsigned int            (*get_divisor)(struct uart_port *,
     120             :                                                unsigned int baud,
     121             :                                                unsigned int *frac);
     122             :         void                    (*set_divisor)(struct uart_port *,
     123             :                                                unsigned int baud,
     124             :                                                unsigned int quot,
     125             :                                                unsigned int quot_frac);
     126             :         int                     (*startup)(struct uart_port *port);
     127             :         void                    (*shutdown)(struct uart_port *port);
     128             :         void                    (*throttle)(struct uart_port *port);
     129             :         void                    (*unthrottle)(struct uart_port *port);
     130             :         int                     (*handle_irq)(struct uart_port *);
     131             :         void                    (*pm)(struct uart_port *, unsigned int state,
     132             :                                       unsigned int old);
     133             :         void                    (*handle_break)(struct uart_port *);
     134             :         int                     (*rs485_config)(struct uart_port *,
     135             :                                                 struct serial_rs485 *rs485);
     136             :         int                     (*iso7816_config)(struct uart_port *,
     137             :                                                   struct serial_iso7816 *iso7816);
     138             :         unsigned int            irq;                    /* irq number */
     139             :         unsigned long           irqflags;               /* irq flags  */
     140             :         unsigned int            uartclk;                /* base uart clock */
     141             :         unsigned int            fifosize;               /* tx fifo size */
     142             :         unsigned char           x_char;                 /* xon/xoff char */
     143             :         unsigned char           regshift;               /* reg offset shift */
     144             :         unsigned char           iotype;                 /* io access style */
     145             :         unsigned char           quirks;                 /* internal quirks */
     146             : 
     147             : #define UPIO_PORT               (SERIAL_IO_PORT)        /* 8b I/O port access */
     148             : #define UPIO_HUB6               (SERIAL_IO_HUB6)        /* Hub6 ISA card */
     149             : #define UPIO_MEM                (SERIAL_IO_MEM)         /* driver-specific */
     150             : #define UPIO_MEM32              (SERIAL_IO_MEM32)       /* 32b little endian */
     151             : #define UPIO_AU                 (SERIAL_IO_AU)          /* Au1x00 and RT288x type IO */
     152             : #define UPIO_TSI                (SERIAL_IO_TSI)         /* Tsi108/109 type IO */
     153             : #define UPIO_MEM32BE            (SERIAL_IO_MEM32BE)     /* 32b big endian */
     154             : #define UPIO_MEM16              (SERIAL_IO_MEM16)       /* 16b little endian */
     155             : 
     156             :         /* quirks must be updated while holding port mutex */
     157             : #define UPQ_NO_TXEN_TEST        BIT(0)
     158             : 
     159             :         unsigned int            read_status_mask;       /* driver specific */
     160             :         unsigned int            ignore_status_mask;     /* driver specific */
     161             :         struct uart_state       *state;                 /* pointer to parent state */
     162             :         struct uart_icount      icount;                 /* statistics */
     163             : 
     164             :         struct console          *cons;                  /* struct console, if any */
     165             :         /* flags must be updated while holding port mutex */
     166             :         upf_t                   flags;
     167             : 
     168             :         /*
     169             :          * These flags must be equivalent to the flags defined in
     170             :          * include/uapi/linux/tty_flags.h which are the userspace definitions
     171             :          * assigned from the serial_struct flags in uart_set_info()
     172             :          * [for bit definitions in the UPF_CHANGE_MASK]
     173             :          *
     174             :          * Bits [0..UPF_LAST_USER] are userspace defined/visible/changeable
     175             :          * The remaining bits are serial-core specific and not modifiable by
     176             :          * userspace.
     177             :          */
     178             : #define UPF_FOURPORT            ((__force upf_t) ASYNC_FOURPORT       /* 1  */ )
     179             : #define UPF_SAK                 ((__force upf_t) ASYNC_SAK            /* 2  */ )
     180             : #define UPF_SPD_HI              ((__force upf_t) ASYNC_SPD_HI         /* 4  */ )
     181             : #define UPF_SPD_VHI             ((__force upf_t) ASYNC_SPD_VHI        /* 5  */ )
     182             : #define UPF_SPD_CUST            ((__force upf_t) ASYNC_SPD_CUST   /* 0x0030 */ )
     183             : #define UPF_SPD_WARP            ((__force upf_t) ASYNC_SPD_WARP   /* 0x1010 */ )
     184             : #define UPF_SPD_MASK            ((__force upf_t) ASYNC_SPD_MASK   /* 0x1030 */ )
     185             : #define UPF_SKIP_TEST           ((__force upf_t) ASYNC_SKIP_TEST      /* 6  */ )
     186             : #define UPF_AUTO_IRQ            ((__force upf_t) ASYNC_AUTO_IRQ       /* 7  */ )
     187             : #define UPF_HARDPPS_CD          ((__force upf_t) ASYNC_HARDPPS_CD     /* 11 */ )
     188             : #define UPF_SPD_SHI             ((__force upf_t) ASYNC_SPD_SHI        /* 12 */ )
     189             : #define UPF_LOW_LATENCY         ((__force upf_t) ASYNC_LOW_LATENCY    /* 13 */ )
     190             : #define UPF_BUGGY_UART          ((__force upf_t) ASYNC_BUGGY_UART     /* 14 */ )
     191             : #define UPF_MAGIC_MULTIPLIER    ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
     192             : 
     193             : #define UPF_NO_THRE_TEST        ((__force upf_t) (1 << 19))
     194             : /* Port has hardware-assisted h/w flow control */
     195             : #define UPF_AUTO_CTS            ((__force upf_t) (1 << 20))
     196             : #define UPF_AUTO_RTS            ((__force upf_t) (1 << 21))
     197             : #define UPF_HARD_FLOW           ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
     198             : /* Port has hardware-assisted s/w flow control */
     199             : #define UPF_SOFT_FLOW           ((__force upf_t) (1 << 22))
     200             : #define UPF_CONS_FLOW           ((__force upf_t) (1 << 23))
     201             : #define UPF_SHARE_IRQ           ((__force upf_t) (1 << 24))
     202             : #define UPF_EXAR_EFR            ((__force upf_t) (1 << 25))
     203             : #define UPF_BUG_THRE            ((__force upf_t) (1 << 26))
     204             : /* The exact UART type is known and should not be probed.  */
     205             : #define UPF_FIXED_TYPE          ((__force upf_t) (1 << 27))
     206             : #define UPF_BOOT_AUTOCONF       ((__force upf_t) (1 << 28))
     207             : #define UPF_FIXED_PORT          ((__force upf_t) (1 << 29))
     208             : #define UPF_DEAD                ((__force upf_t) (1 << 30))
     209             : #define UPF_IOREMAP             ((__force upf_t) (1 << 31))
     210             : 
     211             : #define __UPF_CHANGE_MASK       0x17fff
     212             : #define UPF_CHANGE_MASK         ((__force upf_t) __UPF_CHANGE_MASK)
     213             : #define UPF_USR_MASK            ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
     214             : 
     215             : #if __UPF_CHANGE_MASK > ASYNC_FLAGS
     216             : #error Change mask not equivalent to userspace-visible bit defines
     217             : #endif
     218             : 
     219             :         /*
     220             :          * Must hold termios_rwsem, port mutex and port lock to change;
     221             :          * can hold any one lock to read.
     222             :          */
     223             :         upstat_t                status;
     224             : 
     225             : #define UPSTAT_CTS_ENABLE       ((__force upstat_t) (1 << 0))
     226             : #define UPSTAT_DCD_ENABLE       ((__force upstat_t) (1 << 1))
     227             : #define UPSTAT_AUTORTS          ((__force upstat_t) (1 << 2))
     228             : #define UPSTAT_AUTOCTS          ((__force upstat_t) (1 << 3))
     229             : #define UPSTAT_AUTOXOFF         ((__force upstat_t) (1 << 4))
     230             : #define UPSTAT_SYNC_FIFO        ((__force upstat_t) (1 << 5))
     231             : 
     232             :         int                     hw_stopped;             /* sw-assisted CTS flow state */
     233             :         unsigned int            mctrl;                  /* current modem ctrl settings */
     234             :         unsigned int            timeout;                /* character-based timeout */
     235             :         unsigned int            type;                   /* port type */
     236             :         const struct uart_ops   *ops;
     237             :         unsigned int            custom_divisor;
     238             :         unsigned int            line;                   /* port index */
     239             :         unsigned int            minor;
     240             :         resource_size_t         mapbase;                /* for ioremap */
     241             :         resource_size_t         mapsize;
     242             :         struct device           *dev;                   /* parent device */
     243             : 
     244             :         unsigned long           sysrq;                  /* sysrq timeout */
     245             :         unsigned int            sysrq_ch;               /* char for sysrq */
     246             :         unsigned char           has_sysrq;
     247             :         unsigned char           sysrq_seq;              /* index in sysrq_toggle_seq */
     248             : 
     249             :         unsigned char           hub6;                   /* this should be in the 8250 driver */
     250             :         unsigned char           suspended;
     251             :         unsigned char           console_reinit;
     252             :         const char              *name;                  /* port name */
     253             :         struct attribute_group  *attr_group;            /* port specific attributes */
     254             :         const struct attribute_group **tty_groups;      /* all attributes (serial core use only) */
     255             :         struct serial_rs485     rs485;
     256             :         struct gpio_desc        *rs485_term_gpio;       /* enable RS485 bus termination */
     257             :         struct serial_iso7816   iso7816;
     258             :         void                    *private_data;          /* generic platform data pointer */
     259             : };
     260             : 
     261        2283 : static inline int serial_port_in(struct uart_port *up, int offset)
     262             : {
     263        2276 :         return up->serial_in(up, offset);
     264             : }
     265             : 
     266       14209 : static inline void serial_port_out(struct uart_port *up, int offset, int value)
     267             : {
     268       14209 :         up->serial_out(up, offset, value);
     269         261 : }
     270             : 
     271             : /**
     272             :  * enum uart_pm_state - power states for UARTs
     273             :  * @UART_PM_STATE_ON: UART is powered, up and operational
     274             :  * @UART_PM_STATE_OFF: UART is powered off
     275             :  * @UART_PM_STATE_UNDEFINED: sentinel
     276             :  */
     277             : enum uart_pm_state {
     278             :         UART_PM_STATE_ON = 0,
     279             :         UART_PM_STATE_OFF = 3, /* number taken from ACPI */
     280             :         UART_PM_STATE_UNDEFINED,
     281             : };
     282             : 
     283             : /*
     284             :  * This is the state information which is persistent across opens.
     285             :  */
     286             : struct uart_state {
     287             :         struct tty_port         port;
     288             : 
     289             :         enum uart_pm_state      pm_state;
     290             :         struct circ_buf         xmit;
     291             : 
     292             :         atomic_t                refcount;
     293             :         wait_queue_head_t       remove_wait;
     294             :         struct uart_port        *uart_port;
     295             : };
     296             : 
     297             : #define UART_XMIT_SIZE  PAGE_SIZE
     298             : 
     299             : 
     300             : /* number of characters left in xmit buffer before we ask for more */
     301             : #define WAKEUP_CHARS            256
     302             : 
     303             : struct module;
     304             : struct tty_driver;
     305             : 
     306             : struct uart_driver {
     307             :         struct module           *owner;
     308             :         const char              *driver_name;
     309             :         const char              *dev_name;
     310             :         int                      major;
     311             :         int                      minor;
     312             :         int                      nr;
     313             :         struct console          *cons;
     314             : 
     315             :         /*
     316             :          * these are private; the low level driver should not
     317             :          * touch these; they should be initialised to NULL
     318             :          */
     319             :         struct uart_state       *state;
     320             :         struct tty_driver       *tty_driver;
     321             : };
     322             : 
     323             : void uart_write_wakeup(struct uart_port *port);
     324             : 
     325             : /*
     326             :  * Baud rate helpers.
     327             :  */
     328             : void uart_update_timeout(struct uart_port *port, unsigned int cflag,
     329             :                          unsigned int baud);
     330             : unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
     331             :                                 struct ktermios *old, unsigned int min,
     332             :                                 unsigned int max);
     333             : unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
     334             : 
     335             : /* Base timer interval for polling */
     336           0 : static inline int uart_poll_timeout(struct uart_port *port)
     337             : {
     338           0 :         int timeout = port->timeout;
     339             : 
     340           0 :         return timeout > 6 ? (timeout / 2 - 2) : 1;
     341             : }
     342             : 
     343             : /*
     344             :  * Console helpers.
     345             :  */
     346             : struct earlycon_device {
     347             :         struct console *con;
     348             :         struct uart_port port;
     349             :         char options[16];               /* e.g., 115200n8 */
     350             :         unsigned int baud;
     351             : };
     352             : 
     353             : struct earlycon_id {
     354             :         char    name[15];
     355             :         char    name_term;      /* In case compiler didn't '\0' term name */
     356             :         char    compatible[128];
     357             :         int     (*setup)(struct earlycon_device *, const char *options);
     358             : };
     359             : 
     360             : extern const struct earlycon_id __earlycon_table[];
     361             : extern const struct earlycon_id __earlycon_table_end[];
     362             : 
     363             : #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
     364             : #define EARLYCON_USED_OR_UNUSED __used
     365             : #else
     366             : #define EARLYCON_USED_OR_UNUSED __maybe_unused
     367             : #endif
     368             : 
     369             : #define OF_EARLYCON_DECLARE(_name, compat, fn)                          \
     370             :         static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
     371             :                 EARLYCON_USED_OR_UNUSED  __section("__earlycon_table")  \
     372             :                 __aligned(__alignof__(struct earlycon_id))              \
     373             :                 = { .name = __stringify(_name),                         \
     374             :                     .compatible = compat,                               \
     375             :                     .setup = fn }
     376             : 
     377             : #define EARLYCON_DECLARE(_name, fn)     OF_EARLYCON_DECLARE(_name, "", fn)
     378             : 
     379             : extern int of_setup_earlycon(const struct earlycon_id *match,
     380             :                              unsigned long node,
     381             :                              const char *options);
     382             : 
     383             : #ifdef CONFIG_SERIAL_EARLYCON
     384             : extern bool earlycon_acpi_spcr_enable __initdata;
     385             : int setup_earlycon(char *buf);
     386             : #else
     387             : static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
     388             : static inline int setup_earlycon(char *buf) { return 0; }
     389             : #endif
     390             : 
     391             : struct uart_port *uart_get_console(struct uart_port *ports, int nr,
     392             :                                    struct console *c);
     393             : int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
     394             :                         char **options);
     395             : void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
     396             :                         int *flow);
     397             : int uart_set_options(struct uart_port *port, struct console *co, int baud,
     398             :                      int parity, int bits, int flow);
     399             : struct tty_driver *uart_console_device(struct console *co, int *index);
     400             : void uart_console_write(struct uart_port *port, const char *s,
     401             :                         unsigned int count,
     402             :                         void (*putchar)(struct uart_port *, int));
     403             : 
     404             : /*
     405             :  * Port/driver registration/removal
     406             :  */
     407             : int uart_register_driver(struct uart_driver *uart);
     408             : void uart_unregister_driver(struct uart_driver *uart);
     409             : int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
     410             : int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
     411             : int uart_match_port(struct uart_port *port1, struct uart_port *port2);
     412             : 
     413             : /*
     414             :  * Power Management
     415             :  */
     416             : int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
     417             : int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
     418             : 
     419             : #define uart_circ_empty(circ)           ((circ)->head == (circ)->tail)
     420             : #define uart_circ_clear(circ)           ((circ)->head = (circ)->tail = 0)
     421             : 
     422             : #define uart_circ_chars_pending(circ)   \
     423             :         (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
     424             : 
     425             : #define uart_circ_chars_free(circ)      \
     426             :         (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
     427             : 
     428        1147 : static inline int uart_tx_stopped(struct uart_port *port)
     429             : {
     430        1147 :         struct tty_struct *tty = port->state->port.tty;
     431        1147 :         if ((tty && tty->stopped) || port->hw_stopped)
     432           0 :                 return 1;
     433             :         return 0;
     434             : }
     435             : 
     436             : static inline bool uart_cts_enabled(struct uart_port *uport)
     437             : {
     438             :         return !!(uport->status & UPSTAT_CTS_ENABLE);
     439             : }
     440             : 
     441           1 : static inline bool uart_softcts_mode(struct uart_port *uport)
     442             : {
     443           1 :         upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
     444             : 
     445           1 :         return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
     446             : }
     447             : 
     448             : /*
     449             :  * The following are helper functions for the low level drivers.
     450             :  */
     451             : 
     452             : extern void uart_handle_dcd_change(struct uart_port *uport,
     453             :                 unsigned int status);
     454             : extern void uart_handle_cts_change(struct uart_port *uport,
     455             :                 unsigned int status);
     456             : 
     457             : extern void uart_insert_char(struct uart_port *port, unsigned int status,
     458             :                  unsigned int overrun, unsigned int ch, unsigned int flag);
     459             : 
     460             : #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
     461             : #define SYSRQ_TIMEOUT   (HZ * 5)
     462             : 
     463             : bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch);
     464             : 
     465             : static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
     466             : {
     467             :         if (!port->sysrq)
     468             :                 return 0;
     469             : 
     470             :         if (ch && time_before(jiffies, port->sysrq)) {
     471             :                 if (sysrq_mask()) {
     472             :                         handle_sysrq(ch);
     473             :                         port->sysrq = 0;
     474             :                         return 1;
     475             :                 }
     476             :                 if (uart_try_toggle_sysrq(port, ch))
     477             :                         return 1;
     478             :         }
     479             :         port->sysrq = 0;
     480             : 
     481             :         return 0;
     482             : }
     483             : 
     484             : static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
     485             : {
     486             :         if (!port->sysrq)
     487             :                 return 0;
     488             : 
     489             :         if (ch && time_before(jiffies, port->sysrq)) {
     490             :                 if (sysrq_mask()) {
     491             :                         port->sysrq_ch = ch;
     492             :                         port->sysrq = 0;
     493             :                         return 1;
     494             :                 }
     495             :                 if (uart_try_toggle_sysrq(port, ch))
     496             :                         return 1;
     497             :         }
     498             :         port->sysrq = 0;
     499             : 
     500             :         return 0;
     501             : }
     502             : 
     503             : static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
     504             : {
     505             :         int sysrq_ch;
     506             : 
     507             :         if (!port->has_sysrq) {
     508             :                 spin_unlock_irqrestore(&port->lock, irqflags);
     509             :                 return;
     510             :         }
     511             : 
     512             :         sysrq_ch = port->sysrq_ch;
     513             :         port->sysrq_ch = 0;
     514             : 
     515             :         spin_unlock_irqrestore(&port->lock, irqflags);
     516             : 
     517             :         if (sysrq_ch)
     518             :                 handle_sysrq(sysrq_ch);
     519             : }
     520             : #else   /* CONFIG_MAGIC_SYSRQ_SERIAL */
     521             : static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
     522             : {
     523             :         return 0;
     524             : }
     525           0 : static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
     526             : {
     527           0 :         return 0;
     528             : }
     529         750 : static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
     530             : {
     531         750 :         spin_unlock_irqrestore(&port->lock, irqflags);
     532             : }
     533             : #endif  /* CONFIG_MAGIC_SYSRQ_SERIAL */
     534             : 
     535             : /*
     536             :  * We do the SysRQ and SAK checking like this...
     537             :  */
     538           0 : static inline int uart_handle_break(struct uart_port *port)
     539             : {
     540           0 :         struct uart_state *state = port->state;
     541             : 
     542           0 :         if (port->handle_break)
     543           0 :                 port->handle_break(port);
     544             : 
     545             : #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
     546             :         if (port->has_sysrq && uart_console(port)) {
     547             :                 if (!port->sysrq) {
     548             :                         port->sysrq = jiffies + SYSRQ_TIMEOUT;
     549             :                         return 1;
     550             :                 }
     551             :                 port->sysrq = 0;
     552             :         }
     553             : #endif
     554           0 :         if (port->flags & UPF_SAK)
     555           0 :                 do_SAK(state->port.tty);
     556           0 :         return 0;
     557             : }
     558             : 
     559             : /*
     560             :  *      UART_ENABLE_MS - determine if port should enable modem status irqs
     561             :  */
     562             : #define UART_ENABLE_MS(port,cflag)      ((port)->flags & UPF_HARDPPS_CD || \
     563             :                                          (cflag) & CRTSCTS || \
     564             :                                          !((cflag) & CLOCAL))
     565             : 
     566             : int uart_get_rs485_mode(struct uart_port *port);
     567             : #endif /* LINUX_SERIAL_CORE_H */

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