Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Copyright (C) 2014 Linaro Ltd.
4 : * Author: Rob Herring <robh@kernel.org>
5 : *
6 : * Based on 8250 earlycon:
7 : * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
8 : * Bjorn Helgaas <bjorn.helgaas@hp.com>
9 : */
10 :
11 : #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 :
13 : #include <linux/console.h>
14 : #include <linux/kernel.h>
15 : #include <linux/init.h>
16 : #include <linux/io.h>
17 : #include <linux/serial_core.h>
18 : #include <linux/sizes.h>
19 : #include <linux/of.h>
20 : #include <linux/of_fdt.h>
21 : #include <linux/acpi.h>
22 :
23 : #ifdef CONFIG_FIX_EARLYCON_MEM
24 : #include <asm/fixmap.h>
25 : #endif
26 :
27 : #include <asm/serial.h>
28 :
29 : static struct console early_con = {
30 : .name = "uart", /* fixed up at earlycon registration */
31 : .flags = CON_PRINTBUFFER | CON_BOOT,
32 : .index = 0,
33 : };
34 :
35 : static struct earlycon_device early_console_dev = {
36 : .con = &early_con,
37 : };
38 :
39 0 : static void __iomem * __init earlycon_map(resource_size_t paddr, size_t size)
40 : {
41 0 : void __iomem *base;
42 : #ifdef CONFIG_FIX_EARLYCON_MEM
43 0 : set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr & PAGE_MASK);
44 0 : base = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
45 0 : base += paddr & ~PAGE_MASK;
46 : #else
47 : base = ioremap(paddr, size);
48 : #endif
49 0 : if (!base)
50 : pr_err("%s: Couldn't map %pa\n", __func__, &paddr);
51 :
52 0 : return base;
53 : }
54 :
55 0 : static void __init earlycon_init(struct earlycon_device *device,
56 : const char *name)
57 : {
58 0 : struct console *earlycon = device->con;
59 0 : const char *s;
60 0 : size_t len;
61 :
62 : /* scan backwards from end of string for first non-numeral */
63 0 : for (s = name + strlen(name);
64 0 : s > name && s[-1] >= '0' && s[-1] <= '9';
65 0 : s--)
66 0 : ;
67 0 : if (*s)
68 0 : earlycon->index = simple_strtoul(s, NULL, 10);
69 0 : len = s - name;
70 0 : strlcpy(earlycon->name, name, min(len + 1, sizeof(earlycon->name)));
71 0 : earlycon->data = &early_console_dev;
72 0 : }
73 :
74 0 : static void __init earlycon_print_info(struct earlycon_device *device)
75 : {
76 0 : struct console *earlycon = device->con;
77 0 : struct uart_port *port = &device->port;
78 :
79 0 : if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM16 ||
80 0 : port->iotype == UPIO_MEM32 || port->iotype == UPIO_MEM32BE)
81 0 : pr_info("%s%d at MMIO%s %pa (options '%s')\n",
82 : earlycon->name, earlycon->index,
83 : (port->iotype == UPIO_MEM) ? "" :
84 : (port->iotype == UPIO_MEM16) ? "16" :
85 : (port->iotype == UPIO_MEM32) ? "32" : "32be",
86 : &port->mapbase, device->options);
87 : else
88 0 : pr_info("%s%d at I/O port 0x%lx (options '%s')\n",
89 : earlycon->name, earlycon->index,
90 : port->iobase, device->options);
91 0 : }
92 :
93 0 : static int __init parse_options(struct earlycon_device *device, char *options)
94 : {
95 0 : struct uart_port *port = &device->port;
96 0 : int length;
97 0 : resource_size_t addr;
98 :
99 0 : if (uart_parse_earlycon(options, &port->iotype, &addr, &options))
100 : return -EINVAL;
101 :
102 0 : switch (port->iotype) {
103 0 : case UPIO_MEM:
104 0 : port->mapbase = addr;
105 0 : break;
106 0 : case UPIO_MEM16:
107 0 : port->regshift = 1;
108 0 : port->mapbase = addr;
109 0 : break;
110 0 : case UPIO_MEM32:
111 : case UPIO_MEM32BE:
112 0 : port->regshift = 2;
113 0 : port->mapbase = addr;
114 0 : break;
115 0 : case UPIO_PORT:
116 0 : port->iobase = addr;
117 0 : break;
118 : default:
119 : return -EINVAL;
120 : }
121 :
122 0 : if (options) {
123 0 : device->baud = simple_strtoul(options, NULL, 0);
124 0 : length = min(strcspn(options, " ") + 1,
125 : (size_t)(sizeof(device->options)));
126 0 : strlcpy(device->options, options, length);
127 : }
128 :
129 : return 0;
130 : }
131 :
132 0 : static int __init register_earlycon(char *buf, const struct earlycon_id *match)
133 : {
134 0 : int err;
135 0 : struct uart_port *port = &early_console_dev.port;
136 :
137 : /* On parsing error, pass the options buf to the setup function */
138 0 : if (buf && !parse_options(&early_console_dev, buf))
139 0 : buf = NULL;
140 :
141 0 : spin_lock_init(&port->lock);
142 0 : port->uartclk = BASE_BAUD * 16;
143 0 : if (port->mapbase)
144 0 : port->membase = earlycon_map(port->mapbase, 64);
145 :
146 0 : earlycon_init(&early_console_dev, match->name);
147 0 : err = match->setup(&early_console_dev, buf);
148 0 : earlycon_print_info(&early_console_dev);
149 0 : if (err < 0)
150 : return err;
151 0 : if (!early_console_dev.con->write)
152 : return -ENODEV;
153 :
154 0 : register_console(early_console_dev.con);
155 0 : return 0;
156 : }
157 :
158 : /**
159 : * setup_earlycon - match and register earlycon console
160 : * @buf: earlycon param string
161 : *
162 : * Registers the earlycon console matching the earlycon specified
163 : * in the param string @buf. Acceptable param strings are of the form
164 : * <name>,io|mmio|mmio32|mmio32be,<addr>,<options>
165 : * <name>,0x<addr>,<options>
166 : * <name>,<options>
167 : * <name>
168 : *
169 : * Only for the third form does the earlycon setup() method receive the
170 : * <options> string in the 'options' parameter; all other forms set
171 : * the parameter to NULL.
172 : *
173 : * Returns 0 if an attempt to register the earlycon was made,
174 : * otherwise negative error code
175 : */
176 1 : int __init setup_earlycon(char *buf)
177 : {
178 1 : const struct earlycon_id *match;
179 1 : bool empty_compatible = true;
180 :
181 1 : if (!buf || !buf[0])
182 : return -EINVAL;
183 :
184 1 : if (early_con.flags & CON_ENABLED)
185 : return -EALREADY;
186 :
187 1 : again:
188 14 : for (match = __earlycon_table; match < __earlycon_table_end; match++) {
189 12 : size_t len = strlen(match->name);
190 :
191 12 : if (strncmp(buf, match->name, len))
192 12 : continue;
193 :
194 : /* prefer entries with empty compatible */
195 0 : if (empty_compatible && *match->compatible)
196 0 : continue;
197 :
198 0 : if (buf[len]) {
199 0 : if (buf[len] != ',')
200 0 : continue;
201 0 : buf += len + 1;
202 : } else
203 : buf = NULL;
204 :
205 0 : return register_earlycon(buf, match);
206 : }
207 :
208 2 : if (empty_compatible) {
209 1 : empty_compatible = false;
210 1 : goto again;
211 : }
212 :
213 : return -ENOENT;
214 : }
215 :
216 : /*
217 : * This defers the initialization of the early console until after ACPI has
218 : * been initialized.
219 : */
220 : bool earlycon_acpi_spcr_enable __initdata;
221 :
222 : /* early_param wrapper for setup_earlycon() */
223 1 : static int __init param_setup_earlycon(char *buf)
224 : {
225 1 : int err;
226 :
227 : /* Just 'earlycon' is a valid param for devicetree and ACPI SPCR. */
228 1 : if (!buf || !buf[0]) {
229 0 : if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE)) {
230 : earlycon_acpi_spcr_enable = true;
231 : return 0;
232 0 : } else if (!buf) {
233 : return early_init_dt_scan_chosen_stdout();
234 : }
235 : }
236 :
237 1 : err = setup_earlycon(buf);
238 1 : if (err == -ENOENT || err == -EALREADY)
239 1 : return 0;
240 : return err;
241 : }
242 : early_param("earlycon", param_setup_earlycon);
243 :
244 : #ifdef CONFIG_OF_EARLY_FLATTREE
245 :
246 : int __init of_setup_earlycon(const struct earlycon_id *match,
247 : unsigned long node,
248 : const char *options)
249 : {
250 : int err;
251 : struct uart_port *port = &early_console_dev.port;
252 : const __be32 *val;
253 : bool big_endian;
254 : u64 addr;
255 :
256 : spin_lock_init(&port->lock);
257 : port->iotype = UPIO_MEM;
258 : addr = of_flat_dt_translate_address(node);
259 : if (addr == OF_BAD_ADDR) {
260 : pr_warn("[%s] bad address\n", match->name);
261 : return -ENXIO;
262 : }
263 : port->mapbase = addr;
264 :
265 : val = of_get_flat_dt_prop(node, "reg-offset", NULL);
266 : if (val)
267 : port->mapbase += be32_to_cpu(*val);
268 : port->membase = earlycon_map(port->mapbase, SZ_4K);
269 :
270 : val = of_get_flat_dt_prop(node, "reg-shift", NULL);
271 : if (val)
272 : port->regshift = be32_to_cpu(*val);
273 : big_endian = of_get_flat_dt_prop(node, "big-endian", NULL) != NULL ||
274 : (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
275 : of_get_flat_dt_prop(node, "native-endian", NULL) != NULL);
276 : val = of_get_flat_dt_prop(node, "reg-io-width", NULL);
277 : if (val) {
278 : switch (be32_to_cpu(*val)) {
279 : case 1:
280 : port->iotype = UPIO_MEM;
281 : break;
282 : case 2:
283 : port->iotype = UPIO_MEM16;
284 : break;
285 : case 4:
286 : port->iotype = (big_endian) ? UPIO_MEM32BE : UPIO_MEM32;
287 : break;
288 : default:
289 : pr_warn("[%s] unsupported reg-io-width\n", match->name);
290 : return -EINVAL;
291 : }
292 : }
293 :
294 : val = of_get_flat_dt_prop(node, "current-speed", NULL);
295 : if (val)
296 : early_console_dev.baud = be32_to_cpu(*val);
297 :
298 : val = of_get_flat_dt_prop(node, "clock-frequency", NULL);
299 : if (val)
300 : port->uartclk = be32_to_cpu(*val);
301 :
302 : if (options) {
303 : early_console_dev.baud = simple_strtoul(options, NULL, 0);
304 : strlcpy(early_console_dev.options, options,
305 : sizeof(early_console_dev.options));
306 : }
307 : earlycon_init(&early_console_dev, match->name);
308 : err = match->setup(&early_console_dev, options);
309 : earlycon_print_info(&early_console_dev);
310 : if (err < 0)
311 : return err;
312 : if (!early_console_dev.con->write)
313 : return -ENODEV;
314 :
315 :
316 : register_console(early_console_dev.con);
317 : return 0;
318 : }
319 :
320 : #endif /* CONFIG_OF_EARLY_FLATTREE */
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