2 * Copyright (C) 2014 Linaro Ltd.
3 * Author: Rob Herring <robh@kernel.org>
5 * Based on 8250 earlycon:
6 * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
7 * Bjorn Helgaas <bjorn.helgaas@hp.com>
9 * This program is free software: you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 #include <linux/console.h>
17 #include <linux/kernel.h>
18 #include <linux/init.h>
20 #include <linux/serial_core.h>
21 #include <linux/sizes.h>
22 #include <linux/of_fdt.h>
24 #ifdef CONFIG_FIX_EARLYCON_MEM
25 #include <asm/fixmap.h>
28 #include <asm/serial.h>
30 static struct console early_con = {
31 .name = "uart", /* fixed up at earlycon registration */
32 .flags = CON_PRINTBUFFER | CON_BOOT,
36 static struct earlycon_device early_console_dev = {
40 static void __iomem * __init earlycon_map(unsigned long paddr, size_t size)
43 #ifdef CONFIG_FIX_EARLYCON_MEM
44 set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr & PAGE_MASK);
45 base = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
46 base += paddr & ~PAGE_MASK;
48 base = ioremap(paddr, size);
51 pr_err("%s: Couldn't map 0x%llx\n", __func__,
52 (unsigned long long)paddr);
57 static void __init earlycon_init(struct earlycon_device *device,
60 struct console *earlycon = device->con;
64 /* scan backwards from end of string for first non-numeral */
65 for (s = name + strlen(name);
66 s > name && s[-1] >= '0' && s[-1] <= '9';
70 earlycon->index = simple_strtoul(s, NULL, 10);
72 strlcpy(earlycon->name, name, min(len + 1, sizeof(earlycon->name)));
73 earlycon->data = &early_console_dev;
76 static int __init parse_options(struct earlycon_device *device, char *options)
78 struct uart_port *port = &device->port;
82 if (uart_parse_earlycon(options, &port->iotype, &addr, &options))
85 switch (port->iotype) {
106 device->baud = simple_strtoul(options, NULL, 0);
107 length = min(strcspn(options, " ") + 1,
108 (size_t)(sizeof(device->options)));
109 strlcpy(device->options, options, length);
112 if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM16 ||
113 port->iotype == UPIO_MEM32 || port->iotype == UPIO_MEM32BE)
114 pr_info("Early serial console at MMIO%s 0x%llx (options '%s')\n",
115 (port->iotype == UPIO_MEM) ? "" :
116 (port->iotype == UPIO_MEM16) ? "16" :
117 (port->iotype == UPIO_MEM32) ? "32" : "32be",
118 (unsigned long long)port->mapbase,
121 pr_info("Early serial console at I/O port 0x%lx (options '%s')\n",
128 static int __init register_earlycon(char *buf, const struct earlycon_id *match)
131 struct uart_port *port = &early_console_dev.port;
133 /* On parsing error, pass the options buf to the setup function */
134 if (buf && !parse_options(&early_console_dev, buf))
137 spin_lock_init(&port->lock);
138 port->uartclk = BASE_BAUD * 16;
140 port->membase = earlycon_map(port->mapbase, 64);
142 earlycon_init(&early_console_dev, match->name);
143 err = match->setup(&early_console_dev, buf);
146 if (!early_console_dev.con->write)
149 register_console(early_console_dev.con);
154 * setup_earlycon - match and register earlycon console
155 * @buf: earlycon param string
157 * Registers the earlycon console matching the earlycon specified
158 * in the param string @buf. Acceptable param strings are of the form
159 * <name>,io|mmio|mmio32|mmio32be,<addr>,<options>
160 * <name>,0x<addr>,<options>
164 * Only for the third form does the earlycon setup() method receive the
165 * <options> string in the 'options' parameter; all other forms set
166 * the parameter to NULL.
168 * Returns 0 if an attempt to register the earlycon was made,
169 * otherwise negative error code
171 int __init setup_earlycon(char *buf)
173 const struct earlycon_id *match;
178 if (early_con.flags & CON_ENABLED)
181 for (match = __earlycon_table; match < __earlycon_table_end; match++) {
182 size_t len = strlen(match->name);
184 if (strncmp(buf, match->name, len))
194 return register_earlycon(buf, match);
200 /* early_param wrapper for setup_earlycon() */
201 static int __init param_setup_earlycon(char *buf)
206 * Just 'earlycon' is a valid param for devicetree earlycons;
207 * don't generate a warning from parse_early_params() in that case
212 err = setup_earlycon(buf);
213 if (err == -ENOENT || err == -EALREADY)
217 early_param("earlycon", param_setup_earlycon);
219 #ifdef CONFIG_OF_EARLY_FLATTREE
221 int __init of_setup_earlycon(unsigned long addr,
222 const struct earlycon_id *match,
227 struct uart_port *port = &early_console_dev.port;
231 spin_lock_init(&port->lock);
232 port->iotype = UPIO_MEM;
233 port->mapbase = addr;
234 port->uartclk = BASE_BAUD * 16;
235 port->membase = earlycon_map(addr, SZ_4K);
237 val = of_get_flat_dt_prop(node, "reg-offset", NULL);
239 port->mapbase += be32_to_cpu(*val);
240 val = of_get_flat_dt_prop(node, "reg-shift", NULL);
242 port->regshift = be32_to_cpu(*val);
243 big_endian = of_get_flat_dt_prop(node, "big-endian", NULL) != NULL ||
244 (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
245 of_get_flat_dt_prop(node, "native-endian", NULL) != NULL);
246 val = of_get_flat_dt_prop(node, "reg-io-width", NULL);
248 switch (be32_to_cpu(*val)) {
250 port->iotype = UPIO_MEM;
253 port->iotype = UPIO_MEM16;
256 port->iotype = (big_endian) ? UPIO_MEM32BE : UPIO_MEM32;
259 pr_warn("[%s] unsupported reg-io-width\n", match->name);
265 strlcpy(early_console_dev.options, options,
266 sizeof(early_console_dev.options));
268 earlycon_init(&early_console_dev, match->name);
269 err = match->setup(&early_console_dev, options);
272 if (!early_console_dev.con->write)
276 register_console(early_console_dev.con);
280 #endif /* CONFIG_OF_EARLY_FLATTREE */