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
earlycon_map(resource_size_t paddr,size_t size)39 static 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
earlycon_init(struct earlycon_device * device,const char * name)55 static 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 strlcpy(earlycon->name, name, min(len + 1, sizeof(earlycon->name)));
71 earlycon->data = &early_console_dev;
72 }
73
earlycon_print_info(struct earlycon_device * device)74 static void __init earlycon_print_info(struct earlycon_device *device)
75 {
76 struct console *earlycon = device->con;
77 struct uart_port *port = &device->port;
78
79 if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM16 ||
80 port->iotype == UPIO_MEM32 || port->iotype == UPIO_MEM32BE)
81 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 pr_info("%s%d at I/O port 0x%lx (options '%s')\n",
89 earlycon->name, earlycon->index,
90 port->iobase, device->options);
91 }
92
parse_options(struct earlycon_device * device,char * options)93 static int __init parse_options(struct earlycon_device *device, char *options)
94 {
95 struct uart_port *port = &device->port;
96 int length;
97 resource_size_t addr;
98
99 if (uart_parse_earlycon(options, &port->iotype, &addr, &options))
100 return -EINVAL;
101
102 switch (port->iotype) {
103 case UPIO_MEM:
104 port->mapbase = addr;
105 break;
106 case UPIO_MEM16:
107 port->regshift = 1;
108 port->mapbase = addr;
109 break;
110 case UPIO_MEM32:
111 case UPIO_MEM32BE:
112 port->regshift = 2;
113 port->mapbase = addr;
114 break;
115 case UPIO_PORT:
116 port->iobase = addr;
117 break;
118 default:
119 return -EINVAL;
120 }
121
122 if (options) {
123 device->baud = simple_strtoul(options, NULL, 0);
124 length = min(strcspn(options, " ") + 1,
125 (size_t)(sizeof(device->options)));
126 strlcpy(device->options, options, length);
127 }
128
129 return 0;
130 }
131
register_earlycon(char * buf,const struct earlycon_id * match)132 static int __init register_earlycon(char *buf, const struct earlycon_id *match)
133 {
134 int err;
135 struct uart_port *port = &early_console_dev.port;
136
137 /* On parsing error, pass the options buf to the setup function */
138 if (buf && !parse_options(&early_console_dev, buf))
139 buf = NULL;
140
141 spin_lock_init(&port->lock);
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 */
setup_earlycon(char * buf)176 int __init setup_earlycon(char *buf)
177 {
178 const struct earlycon_id **p_match;
179 bool empty_compatible = true;
180
181 if (!buf || !buf[0])
182 return -EINVAL;
183
184 if (early_con.flags & CON_ENABLED)
185 return -EALREADY;
186
187 again:
188 for (p_match = __earlycon_table; p_match < __earlycon_table_end;
189 p_match++) {
190 const struct earlycon_id *match = *p_match;
191 size_t len = strlen(match->name);
192
193 if (strncmp(buf, match->name, len))
194 continue;
195
196 /* prefer entries with empty compatible */
197 if (empty_compatible && *match->compatible)
198 continue;
199
200 if (buf[len]) {
201 if (buf[len] != ',')
202 continue;
203 buf += len + 1;
204 } else
205 buf = NULL;
206
207 return register_earlycon(buf, match);
208 }
209
210 if (empty_compatible) {
211 empty_compatible = false;
212 goto again;
213 }
214
215 return -ENOENT;
216 }
217
218 /*
219 * This defers the initialization of the early console until after ACPI has
220 * been initialized.
221 */
222 bool earlycon_acpi_spcr_enable __initdata;
223
224 /* early_param wrapper for setup_earlycon() */
param_setup_earlycon(char * buf)225 static int __init param_setup_earlycon(char *buf)
226 {
227 int err;
228
229 /* Just 'earlycon' is a valid param for devicetree and ACPI SPCR. */
230 if (!buf || !buf[0]) {
231 if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE)) {
232 earlycon_acpi_spcr_enable = true;
233 return 0;
234 } else if (!buf) {
235 return early_init_dt_scan_chosen_stdout();
236 }
237 }
238
239 err = setup_earlycon(buf);
240 if (err == -ENOENT || err == -EALREADY)
241 return 0;
242 return err;
243 }
244 early_param("earlycon", param_setup_earlycon);
245
246 #ifdef CONFIG_OF_EARLY_FLATTREE
247
of_setup_earlycon(const struct earlycon_id * match,unsigned long node,const char * options)248 int __init of_setup_earlycon(const struct earlycon_id *match,
249 unsigned long node,
250 const char *options)
251 {
252 int err;
253 struct uart_port *port = &early_console_dev.port;
254 const __be32 *val;
255 bool big_endian;
256 u64 addr;
257
258 spin_lock_init(&port->lock);
259 port->iotype = UPIO_MEM;
260 addr = of_flat_dt_translate_address(node);
261 if (addr == OF_BAD_ADDR) {
262 pr_warn("[%s] bad address\n", match->name);
263 return -ENXIO;
264 }
265 port->mapbase = addr;
266
267 val = of_get_flat_dt_prop(node, "reg-offset", NULL);
268 if (val)
269 port->mapbase += be32_to_cpu(*val);
270 port->membase = earlycon_map(port->mapbase, SZ_4K);
271
272 val = of_get_flat_dt_prop(node, "reg-shift", NULL);
273 if (val)
274 port->regshift = be32_to_cpu(*val);
275 big_endian = of_get_flat_dt_prop(node, "big-endian", NULL) != NULL ||
276 (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
277 of_get_flat_dt_prop(node, "native-endian", NULL) != NULL);
278 val = of_get_flat_dt_prop(node, "reg-io-width", NULL);
279 if (val) {
280 switch (be32_to_cpu(*val)) {
281 case 1:
282 port->iotype = UPIO_MEM;
283 break;
284 case 2:
285 port->iotype = UPIO_MEM16;
286 break;
287 case 4:
288 port->iotype = (big_endian) ? UPIO_MEM32BE : UPIO_MEM32;
289 break;
290 default:
291 pr_warn("[%s] unsupported reg-io-width\n", match->name);
292 return -EINVAL;
293 }
294 }
295
296 val = of_get_flat_dt_prop(node, "current-speed", NULL);
297 if (val)
298 early_console_dev.baud = be32_to_cpu(*val);
299
300 val = of_get_flat_dt_prop(node, "clock-frequency", NULL);
301 if (val)
302 port->uartclk = be32_to_cpu(*val);
303
304 if (options) {
305 early_console_dev.baud = simple_strtoul(options, NULL, 0);
306 strlcpy(early_console_dev.options, options,
307 sizeof(early_console_dev.options));
308 }
309 earlycon_init(&early_console_dev, match->name);
310 err = match->setup(&early_console_dev, options);
311 earlycon_print_info(&early_console_dev);
312 if (err < 0)
313 return err;
314 if (!early_console_dev.con->write)
315 return -ENODEV;
316
317
318 register_console(early_console_dev.con);
319 return 0;
320 }
321
322 #endif /* CONFIG_OF_EARLY_FLATTREE */
323