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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
29static struct console early_con = {
30 .name = "uart", /* fixed up at earlycon registration */
31 .flags = CON_PRINTBUFFER | CON_BOOT,
32 .index = 0,
33};
34
35static struct earlycon_device early_console_dev = {
36 .con = &early_con,
37};
38
39static void __iomem * __init earlycon_map(resource_size_t paddr, size_t size)
40{
41 void __iomem *base;
42#ifdef CONFIG_FIX_EARLYCON_MEM
43 set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr & PAGE_MASK);
44 base = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
45 base += paddr & ~PAGE_MASK;
46#else
47 base = ioremap(paddr, size);
48#endif
49 if (!base)
50 pr_err("%s: Couldn't map %pa\n", __func__, &paddr);
51
52 return base;
53}
54
55static void __init earlycon_init(struct earlycon_device *device,
56 const char *name)
57{
58 struct console *earlycon = device->con;
59 const char *s;
60 size_t len;
61
62 /* scan backwards from end of string for first non-numeral */
63 for (s = name + strlen(name);
64 s > name && s[-1] >= '0' && s[-1] <= '9';
65 s--)
66 ;
67 if (*s)
68 earlycon->index = simple_strtoul(s, NULL, 10);
69 len = s - name;
70 strscpy(earlycon->name, name, min(len + 1, sizeof(earlycon->name)));
71 earlycon->data = &early_console_dev;
72}
73
74static void __init earlycon_print_info(struct earlycon_device *device)
75{
76 struct console *earlycon = device->con;
77 struct uart_port *port = &device->port;
78 char ioinfos[64];
79
80 uart_get_ioinfos(port, ioinfos, sizeof(ioinfos));
81
82 pr_info("%s%d%s (options '%s')\n", earlycon->name, earlycon->index,
83 ioinfos, device->options);
84}
85
86static int __init parse_options(struct earlycon_device *device, char *options)
87{
88 struct uart_port *port = &device->port;
89 int length;
90 resource_size_t addr;
91
92 if (uart_parse_earlycon(options, &port->iotype, &addr, &options))
93 return -EINVAL;
94
95 switch (port->iotype) {
96 case UPIO_MEM:
97 port->mapbase = addr;
98 break;
99 case UPIO_MEM16:
100 port->regshift = 1;
101 port->mapbase = addr;
102 break;
103 case UPIO_MEM32:
104 case UPIO_MEM32BE:
105 port->regshift = 2;
106 port->mapbase = addr;
107 break;
108 case UPIO_PORT:
109 port->iobase = addr;
110 break;
111 default:
112 return -EINVAL;
113 }
114
115 if (options) {
116 char *uartclk;
117
118 device->baud = simple_strtoul(options, NULL, 0);
119 uartclk = strchr(options, ',');
120 if (uartclk && kstrtouint(uartclk + 1, 0, &port->uartclk) < 0)
121 pr_warn("[%s] unsupported earlycon uart clkrate option\n",
122 options);
123 length = min(strcspn(options, " ") + 1,
124 (size_t)(sizeof(device->options)));
125 strscpy(device->options, options, length);
126 }
127
128 return 0;
129}
130
131static int __init register_earlycon(char *buf, const struct earlycon_id *match)
132{
133 int err;
134 struct uart_port *port = &early_console_dev.port;
135
136 /* On parsing error, pass the options buf to the setup function */
137 if (buf && !parse_options(&early_console_dev, buf))
138 buf = NULL;
139
140 spin_lock_init(&port->lock);
141 if (!port->uartclk)
142 port->uartclk = BASE_BAUD * 16;
143 if (port->mapbase)
144 port->membase = earlycon_map(port->mapbase, 64);
145
146 earlycon_init(&early_console_dev, match->name);
147 err = match->setup(&early_console_dev, buf);
148 earlycon_print_info(&early_console_dev);
149 if (err < 0)
150 return err;
151 if (!early_console_dev.con->write)
152 return -ENODEV;
153
154 register_console(early_console_dev.con);
155 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 */
176int __init setup_earlycon(char *buf)
177{
178 const struct earlycon_id *match;
179 bool empty_compatible = true;
180
181 if (!buf || !buf[0])
182 return -EINVAL;
183
184 if (console_is_registered(&early_con))
185 return -EALREADY;
186
187again:
188 for (match = __earlycon_table; match < __earlycon_table_end; match++) {
189 size_t len = strlen(match->name);
190
191 if (strncmp(buf, match->name, len))
192 continue;
193
194 /* prefer entries with empty compatible */
195 if (empty_compatible && *match->compatible)
196 continue;
197
198 if (buf[len]) {
199 if (buf[len] != ',')
200 continue;
201 buf += len + 1;
202 } else
203 buf = NULL;
204
205 return register_earlycon(buf, match);
206 }
207
208 if (empty_compatible) {
209 empty_compatible = false;
210 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 */
220bool earlycon_acpi_spcr_enable __initdata;
221
222/* early_param wrapper for setup_earlycon() */
223static int __init param_setup_earlycon(char *buf)
224{
225 int err;
226
227 /* Just 'earlycon' is a valid param for devicetree and ACPI SPCR. */
228 if (!buf || !buf[0]) {
229 if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE)) {
230 earlycon_acpi_spcr_enable = true;
231 return 0;
232 } else if (!buf) {
233 return early_init_dt_scan_chosen_stdout();
234 }
235 }
236
237 err = setup_earlycon(buf);
238 if (err == -ENOENT || err == -EALREADY)
239 return 0;
240 return err;
241}
242early_param("earlycon", param_setup_earlycon);
243
244/*
245 * The `console` parameter is overloaded. It's handled here as an early param
246 * and in `printk.c` as a late param. It's possible to specify an early
247 * `bootconsole` using `earlycon=uartXXXX` (handled above), or via
248 * the `console=uartXXX` alias. See the comment in `8250_early.c`.
249 */
250static int __init param_setup_earlycon_console_alias(char *buf)
251{
252 /*
253 * A plain `console` parameter must not enable the SPCR `bootconsole`
254 * like a plain `earlycon` does.
255 *
256 * A `console=` parameter that specifies an empty value is used to
257 * disable the `console`, not the `earlycon` `bootconsole`. The
258 * disabling of the `console` is handled by `printk.c`.
259 */
260 if (!buf || !buf[0])
261 return 0;
262
263 return param_setup_earlycon(buf);
264}
265early_param("console", param_setup_earlycon_console_alias);
266
267#ifdef CONFIG_OF_EARLY_FLATTREE
268
269int __init of_setup_earlycon(const struct earlycon_id *match,
270 unsigned long node,
271 const char *options)
272{
273 int err;
274 struct uart_port *port = &early_console_dev.port;
275 const __be32 *val;
276 bool big_endian;
277 u64 addr;
278
279 if (console_is_registered(&early_con))
280 return -EALREADY;
281
282 spin_lock_init(&port->lock);
283 port->iotype = UPIO_MEM;
284 addr = of_flat_dt_translate_address(node);
285 if (addr == OF_BAD_ADDR) {
286 pr_warn("[%s] bad address\n", match->name);
287 return -ENXIO;
288 }
289 port->mapbase = addr;
290
291 val = of_get_flat_dt_prop(node, "reg-offset", NULL);
292 if (val)
293 port->mapbase += be32_to_cpu(*val);
294 port->membase = earlycon_map(port->mapbase, SZ_4K);
295
296 val = of_get_flat_dt_prop(node, "reg-shift", NULL);
297 if (val)
298 port->regshift = be32_to_cpu(*val);
299 big_endian = of_get_flat_dt_prop(node, "big-endian", NULL) != NULL ||
300 (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
301 of_get_flat_dt_prop(node, "native-endian", NULL) != NULL);
302 val = of_get_flat_dt_prop(node, "reg-io-width", NULL);
303 if (val) {
304 switch (be32_to_cpu(*val)) {
305 case 1:
306 port->iotype = UPIO_MEM;
307 break;
308 case 2:
309 port->iotype = UPIO_MEM16;
310 break;
311 case 4:
312 port->iotype = (big_endian) ? UPIO_MEM32BE : UPIO_MEM32;
313 break;
314 default:
315 pr_warn("[%s] unsupported reg-io-width\n", match->name);
316 return -EINVAL;
317 }
318 }
319
320 val = of_get_flat_dt_prop(node, "current-speed", NULL);
321 if (val)
322 early_console_dev.baud = be32_to_cpu(*val);
323
324 val = of_get_flat_dt_prop(node, "clock-frequency", NULL);
325 if (val)
326 port->uartclk = be32_to_cpu(*val);
327
328 if (options) {
329 early_console_dev.baud = simple_strtoul(options, NULL, 0);
330 strscpy(early_console_dev.options, options,
331 sizeof(early_console_dev.options));
332 }
333 earlycon_init(&early_console_dev, match->name);
334 err = match->setup(&early_console_dev, options);
335 earlycon_print_info(&early_console_dev);
336 if (err < 0)
337 return err;
338 if (!early_console_dev.con->write)
339 return -ENODEV;
340
341
342 register_console(early_console_dev.con);
343 return 0;
344}
345
346#endif /* CONFIG_OF_EARLY_FLATTREE */