Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Copyright (C) 2014 Linaro Ltd.
4 : * Author: Rob Herring <[email protected]>
5 : *
6 : * Based on 8250 earlycon:
7 : * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
8 : * Bjorn Helgaas <[email protected]>
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 0 : pr_err("%s: Couldn't map %pa\n", __func__, &paddr);
51 :
52 0 : return base;
53 0 : }
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 : ;
67 0 : if (*s)
68 0 : earlycon->index = simple_strtoul(s, NULL, 10);
69 0 : len = s - name;
70 0 : strscpy(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 0 : return -EINVAL;
101 :
102 0 : switch (port->iotype) {
103 : case UPIO_MEM:
104 0 : port->mapbase = addr;
105 0 : break;
106 : case UPIO_MEM16:
107 0 : port->regshift = 1;
108 0 : port->mapbase = addr;
109 0 : break;
110 : case UPIO_MEM32:
111 : case UPIO_MEM32BE:
112 0 : port->regshift = 2;
113 0 : port->mapbase = addr;
114 0 : break;
115 : case UPIO_PORT:
116 0 : port->iobase = addr;
117 0 : break;
118 : default:
119 0 : return -EINVAL;
120 : }
121 :
122 0 : if (options) {
123 0 : char *uartclk;
124 :
125 0 : device->baud = simple_strtoul(options, NULL, 0);
126 0 : uartclk = strchr(options, ',');
127 0 : if (uartclk && kstrtouint(uartclk + 1, 0, &port->uartclk) < 0)
128 0 : pr_warn("[%s] unsupported earlycon uart clkrate option\n",
129 : options);
130 0 : length = min(strcspn(options, " ") + 1,
131 : (size_t)(sizeof(device->options)));
132 0 : strscpy(device->options, options, length);
133 0 : }
134 :
135 0 : return 0;
136 0 : }
137 :
138 0 : static int __init register_earlycon(char *buf, const struct earlycon_id *match)
139 : {
140 0 : int err;
141 0 : struct uart_port *port = &early_console_dev.port;
142 :
143 : /* On parsing error, pass the options buf to the setup function */
144 0 : if (buf && !parse_options(&early_console_dev, buf))
145 0 : buf = NULL;
146 :
147 0 : spin_lock_init(&port->lock);
148 0 : if (!port->uartclk)
149 0 : port->uartclk = BASE_BAUD * 16;
150 0 : if (port->mapbase)
151 0 : port->membase = earlycon_map(port->mapbase, 64);
152 :
153 0 : earlycon_init(&early_console_dev, match->name);
154 0 : err = match->setup(&early_console_dev, buf);
155 0 : earlycon_print_info(&early_console_dev);
156 0 : if (err < 0)
157 0 : return err;
158 0 : if (!early_console_dev.con->write)
159 0 : return -ENODEV;
160 :
161 0 : register_console(early_console_dev.con);
162 0 : return 0;
163 0 : }
164 :
165 : /**
166 : * setup_earlycon - match and register earlycon console
167 : * @buf: earlycon param string
168 : *
169 : * Registers the earlycon console matching the earlycon specified
170 : * in the param string @buf. Acceptable param strings are of the form
171 : * <name>,io|mmio|mmio32|mmio32be,<addr>,<options>
172 : * <name>,0x<addr>,<options>
173 : * <name>,<options>
174 : * <name>
175 : *
176 : * Only for the third form does the earlycon setup() method receive the
177 : * <options> string in the 'options' parameter; all other forms set
178 : * the parameter to NULL.
179 : *
180 : * Returns 0 if an attempt to register the earlycon was made,
181 : * otherwise negative error code
182 : */
183 0 : int __init setup_earlycon(char *buf)
184 : {
185 0 : const struct earlycon_id *match;
186 0 : bool empty_compatible = true;
187 :
188 0 : if (!buf || !buf[0])
189 0 : return -EINVAL;
190 :
191 0 : if (console_is_registered(&early_con))
192 0 : return -EALREADY;
193 :
194 : again:
195 0 : for (match = __earlycon_table; match < __earlycon_table_end; match++) {
196 0 : size_t len = strlen(match->name);
197 :
198 0 : if (strncmp(buf, match->name, len))
199 0 : continue;
200 :
201 : /* prefer entries with empty compatible */
202 0 : if (empty_compatible && *match->compatible)
203 0 : continue;
204 :
205 0 : if (buf[len]) {
206 0 : if (buf[len] != ',')
207 0 : continue;
208 0 : buf += len + 1;
209 0 : } else
210 0 : buf = NULL;
211 :
212 0 : return register_earlycon(buf, match);
213 0 : }
214 :
215 0 : if (empty_compatible) {
216 0 : empty_compatible = false;
217 0 : goto again;
218 : }
219 :
220 0 : return -ENOENT;
221 0 : }
222 :
223 : /*
224 : * This defers the initialization of the early console until after ACPI has
225 : * been initialized.
226 : */
227 : bool earlycon_acpi_spcr_enable __initdata;
228 :
229 : /* early_param wrapper for setup_earlycon() */
230 0 : static int __init param_setup_earlycon(char *buf)
231 : {
232 0 : int err;
233 :
234 : /* Just 'earlycon' is a valid param for devicetree and ACPI SPCR. */
235 0 : if (!buf || !buf[0]) {
236 : if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE)) {
237 0 : earlycon_acpi_spcr_enable = true;
238 0 : return 0;
239 : } else if (!buf) {
240 : return early_init_dt_scan_chosen_stdout();
241 : }
242 : }
243 :
244 0 : err = setup_earlycon(buf);
245 0 : if (err == -ENOENT || err == -EALREADY)
246 0 : return 0;
247 0 : return err;
248 0 : }
249 : early_param("earlycon", param_setup_earlycon);
250 :
251 : /*
252 : * The `console` parameter is overloaded. It's handled here as an early param
253 : * and in `printk.c` as a late param. It's possible to specify an early
254 : * `bootconsole` using `earlycon=uartXXXX` (handled above), or via
255 : * the `console=uartXXX` alias. See the comment in `8250_early.c`.
256 : */
257 0 : static int __init param_setup_earlycon_console_alias(char *buf)
258 : {
259 : /*
260 : * A plain `console` parameter must not enable the SPCR `bootconsole`
261 : * like a plain `earlycon` does.
262 : *
263 : * A `console=` parameter that specifies an empty value is used to
264 : * disable the `console`, not the `earlycon` `bootconsole`. The
265 : * disabling of the `console` is handled by `printk.c`.
266 : */
267 0 : if (!buf || !buf[0])
268 0 : return 0;
269 :
270 0 : return param_setup_earlycon(buf);
271 0 : }
272 : early_param("console", param_setup_earlycon_console_alias);
273 :
274 : #ifdef CONFIG_OF_EARLY_FLATTREE
275 :
276 : int __init of_setup_earlycon(const struct earlycon_id *match,
277 : unsigned long node,
278 : const char *options)
279 : {
280 : int err;
281 : struct uart_port *port = &early_console_dev.port;
282 : const __be32 *val;
283 : bool big_endian;
284 : u64 addr;
285 :
286 : if (console_is_registered(&early_con))
287 : return -EALREADY;
288 :
289 : spin_lock_init(&port->lock);
290 : port->iotype = UPIO_MEM;
291 : addr = of_flat_dt_translate_address(node);
292 : if (addr == OF_BAD_ADDR) {
293 : pr_warn("[%s] bad address\n", match->name);
294 : return -ENXIO;
295 : }
296 : port->mapbase = addr;
297 :
298 : val = of_get_flat_dt_prop(node, "reg-offset", NULL);
299 : if (val)
300 : port->mapbase += be32_to_cpu(*val);
301 : port->membase = earlycon_map(port->mapbase, SZ_4K);
302 :
303 : val = of_get_flat_dt_prop(node, "reg-shift", NULL);
304 : if (val)
305 : port->regshift = be32_to_cpu(*val);
306 : big_endian = of_get_flat_dt_prop(node, "big-endian", NULL) != NULL ||
307 : (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
308 : of_get_flat_dt_prop(node, "native-endian", NULL) != NULL);
309 : val = of_get_flat_dt_prop(node, "reg-io-width", NULL);
310 : if (val) {
311 : switch (be32_to_cpu(*val)) {
312 : case 1:
313 : port->iotype = UPIO_MEM;
314 : break;
315 : case 2:
316 : port->iotype = UPIO_MEM16;
317 : break;
318 : case 4:
319 : port->iotype = (big_endian) ? UPIO_MEM32BE : UPIO_MEM32;
320 : break;
321 : default:
322 : pr_warn("[%s] unsupported reg-io-width\n", match->name);
323 : return -EINVAL;
324 : }
325 : }
326 :
327 : val = of_get_flat_dt_prop(node, "current-speed", NULL);
328 : if (val)
329 : early_console_dev.baud = be32_to_cpu(*val);
330 :
331 : val = of_get_flat_dt_prop(node, "clock-frequency", NULL);
332 : if (val)
333 : port->uartclk = be32_to_cpu(*val);
334 :
335 : if (options) {
336 : early_console_dev.baud = simple_strtoul(options, NULL, 0);
337 : strscpy(early_console_dev.options, options,
338 : sizeof(early_console_dev.options));
339 : }
340 : earlycon_init(&early_console_dev, match->name);
341 : err = match->setup(&early_console_dev, options);
342 : earlycon_print_info(&early_console_dev);
343 : if (err < 0)
344 : return err;
345 : if (!early_console_dev.con->write)
346 : return -ENODEV;
347 :
348 :
349 : register_console(early_console_dev.con);
350 : return 0;
351 : }
352 :
353 : #endif /* CONFIG_OF_EARLY_FLATTREE */
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