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>
23 #include <linux/of_fdt.h>
24 #include <linux/acpi.h>
26 #ifdef CONFIG_FIX_EARLYCON_MEM
27 #include <asm/fixmap.h>
30 #include <asm/serial.h>
32 static struct console early_con
= {
33 .name
= "uart", /* fixed up at earlycon registration */
34 .flags
= CON_PRINTBUFFER
| CON_BOOT
,
38 static struct earlycon_device early_console_dev
= {
42 static void __iomem
* __init
earlycon_map(resource_size_t paddr
, size_t size
)
45 #ifdef CONFIG_FIX_EARLYCON_MEM
46 set_fixmap_io(FIX_EARLYCON_MEM_BASE
, paddr
& PAGE_MASK
);
47 base
= (void __iomem
*)__fix_to_virt(FIX_EARLYCON_MEM_BASE
);
48 base
+= paddr
& ~PAGE_MASK
;
50 base
= ioremap(paddr
, size
);
53 pr_err("%s: Couldn't map %pa\n", __func__
, &paddr
);
58 static void __init
earlycon_init(struct earlycon_device
*device
,
61 struct console
*earlycon
= device
->con
;
62 struct uart_port
*port
= &device
->port
;
66 /* scan backwards from end of string for first non-numeral */
67 for (s
= name
+ strlen(name
);
68 s
> name
&& s
[-1] >= '0' && s
[-1] <= '9';
72 earlycon
->index
= simple_strtoul(s
, NULL
, 10);
74 strlcpy(earlycon
->name
, name
, min(len
+ 1, sizeof(earlycon
->name
)));
75 earlycon
->data
= &early_console_dev
;
77 if (port
->iotype
== UPIO_MEM
|| port
->iotype
== UPIO_MEM16
||
78 port
->iotype
== UPIO_MEM32
|| port
->iotype
== UPIO_MEM32BE
)
79 pr_info("%s%d at MMIO%s %pa (options '%s')\n",
80 earlycon
->name
, earlycon
->index
,
81 (port
->iotype
== UPIO_MEM
) ? "" :
82 (port
->iotype
== UPIO_MEM16
) ? "16" :
83 (port
->iotype
== UPIO_MEM32
) ? "32" : "32be",
84 &port
->mapbase
, device
->options
);
86 pr_info("%s%d at I/O port 0x%lx (options '%s')\n",
87 earlycon
->name
, earlycon
->index
,
88 port
->iobase
, device
->options
);
91 static int __init
parse_options(struct earlycon_device
*device
, char *options
)
93 struct uart_port
*port
= &device
->port
;
97 if (uart_parse_earlycon(options
, &port
->iotype
, &addr
, &options
))
100 switch (port
->iotype
) {
102 port
->mapbase
= addr
;
106 port
->mapbase
= addr
;
111 port
->mapbase
= addr
;
121 device
->baud
= simple_strtoul(options
, NULL
, 0);
122 length
= min(strcspn(options
, " ") + 1,
123 (size_t)(sizeof(device
->options
)));
124 strlcpy(device
->options
, options
, length
);
130 static int __init
register_earlycon(char *buf
, const struct earlycon_id
*match
)
133 struct uart_port
*port
= &early_console_dev
.port
;
135 /* On parsing error, pass the options buf to the setup function */
136 if (buf
&& !parse_options(&early_console_dev
, buf
))
139 spin_lock_init(&port
->lock
);
140 port
->uartclk
= BASE_BAUD
* 16;
142 port
->membase
= earlycon_map(port
->mapbase
, 64);
144 earlycon_init(&early_console_dev
, match
->name
);
145 err
= match
->setup(&early_console_dev
, buf
);
148 if (!early_console_dev
.con
->write
)
151 register_console(early_console_dev
.con
);
156 * setup_earlycon - match and register earlycon console
157 * @buf: earlycon param string
159 * Registers the earlycon console matching the earlycon specified
160 * in the param string @buf. Acceptable param strings are of the form
161 * <name>,io|mmio|mmio32|mmio32be,<addr>,<options>
162 * <name>,0x<addr>,<options>
166 * Only for the third form does the earlycon setup() method receive the
167 * <options> string in the 'options' parameter; all other forms set
168 * the parameter to NULL.
170 * Returns 0 if an attempt to register the earlycon was made,
171 * otherwise negative error code
173 int __init
setup_earlycon(char *buf
)
175 const struct earlycon_id
*match
;
180 if (early_con
.flags
& CON_ENABLED
)
183 for (match
= __earlycon_table
; match
< __earlycon_table_end
; match
++) {
184 size_t len
= strlen(match
->name
);
186 if (strncmp(buf
, match
->name
, len
))
196 return register_earlycon(buf
, match
);
203 * When CONFIG_ACPI_SPCR_TABLE is defined, "earlycon" without parameters in
204 * command line does not start DT earlycon immediately, instead it defers
205 * starting it until DT/ACPI decision is made. At that time if ACPI is enabled
206 * call parse_spcr(), else call early_init_dt_scan_chosen_stdout()
208 bool earlycon_init_is_deferred __initdata
;
210 /* early_param wrapper for setup_earlycon() */
211 static int __init
param_setup_earlycon(char *buf
)
216 * Just 'earlycon' is a valid param for devicetree earlycons;
217 * don't generate a warning from parse_early_params() in that case
219 if (!buf
|| !buf
[0]) {
220 if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE
)) {
221 earlycon_init_is_deferred
= true;
224 return early_init_dt_scan_chosen_stdout();
228 err
= setup_earlycon(buf
);
229 if (err
== -ENOENT
|| err
== -EALREADY
)
233 early_param("earlycon", param_setup_earlycon
);
235 #ifdef CONFIG_OF_EARLY_FLATTREE
237 int __init
of_setup_earlycon(const struct earlycon_id
*match
,
242 struct uart_port
*port
= &early_console_dev
.port
;
247 spin_lock_init(&port
->lock
);
248 port
->iotype
= UPIO_MEM
;
249 addr
= of_flat_dt_translate_address(node
);
250 if (addr
== OF_BAD_ADDR
) {
251 pr_warn("[%s] bad address\n", match
->name
);
254 port
->mapbase
= addr
;
255 port
->uartclk
= BASE_BAUD
* 16;
256 port
->membase
= earlycon_map(port
->mapbase
, SZ_4K
);
258 val
= of_get_flat_dt_prop(node
, "reg-offset", NULL
);
260 port
->mapbase
+= be32_to_cpu(*val
);
261 val
= of_get_flat_dt_prop(node
, "reg-shift", NULL
);
263 port
->regshift
= be32_to_cpu(*val
);
264 big_endian
= of_get_flat_dt_prop(node
, "big-endian", NULL
) != NULL
||
265 (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN
) &&
266 of_get_flat_dt_prop(node
, "native-endian", NULL
) != NULL
);
267 val
= of_get_flat_dt_prop(node
, "reg-io-width", NULL
);
269 switch (be32_to_cpu(*val
)) {
271 port
->iotype
= UPIO_MEM
;
274 port
->iotype
= UPIO_MEM16
;
277 port
->iotype
= (big_endian
) ? UPIO_MEM32BE
: UPIO_MEM32
;
280 pr_warn("[%s] unsupported reg-io-width\n", match
->name
);
286 strlcpy(early_console_dev
.options
, options
,
287 sizeof(early_console_dev
.options
));
289 earlycon_init(&early_console_dev
, match
->name
);
290 err
= match
->setup(&early_console_dev
, options
);
293 if (!early_console_dev
.con
->write
)
297 register_console(early_console_dev
.con
);
301 #endif /* CONFIG_OF_EARLY_FLATTREE */