1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2014 Linaro Ltd.
4 * Author: Rob Herring <robh@kernel.org>
6 * Based on 8250 earlycon:
7 * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
8 * Bjorn Helgaas <bjorn.helgaas@hp.com>
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/console.h>
14 #include <linux/kernel.h>
15 #include <linux/init.h>
17 #include <linux/serial_core.h>
18 #include <linux/sizes.h>
20 #include <linux/of_fdt.h>
21 #include <linux/acpi.h>
23 #ifdef CONFIG_FIX_EARLYCON_MEM
24 #include <asm/fixmap.h>
27 #include <asm/serial.h>
29 static struct console early_con
= {
30 .name
= "uart", /* fixed up at earlycon registration */
31 .flags
= CON_PRINTBUFFER
| CON_BOOT
,
35 static struct earlycon_device early_console_dev
= {
39 static void __iomem
* __init
earlycon_map(resource_size_t paddr
, size_t size
)
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
;
47 base
= ioremap(paddr
, size
);
50 pr_err("%s: Couldn't map %pa\n", __func__
, &paddr
);
55 static void __init
earlycon_init(struct earlycon_device
*device
,
58 struct console
*earlycon
= device
->con
;
59 struct uart_port
*port
= &device
->port
;
63 /* scan backwards from end of string for first non-numeral */
64 for (s
= name
+ strlen(name
);
65 s
> name
&& s
[-1] >= '0' && s
[-1] <= '9';
69 earlycon
->index
= simple_strtoul(s
, NULL
, 10);
71 strlcpy(earlycon
->name
, name
, min(len
+ 1, sizeof(earlycon
->name
)));
72 earlycon
->data
= &early_console_dev
;
74 if (port
->iotype
== UPIO_MEM
|| port
->iotype
== UPIO_MEM16
||
75 port
->iotype
== UPIO_MEM32
|| port
->iotype
== UPIO_MEM32BE
)
76 pr_info("%s%d at MMIO%s %pa (options '%s')\n",
77 earlycon
->name
, earlycon
->index
,
78 (port
->iotype
== UPIO_MEM
) ? "" :
79 (port
->iotype
== UPIO_MEM16
) ? "16" :
80 (port
->iotype
== UPIO_MEM32
) ? "32" : "32be",
81 &port
->mapbase
, device
->options
);
83 pr_info("%s%d at I/O port 0x%lx (options '%s')\n",
84 earlycon
->name
, earlycon
->index
,
85 port
->iobase
, device
->options
);
88 static int __init
parse_options(struct earlycon_device
*device
, char *options
)
90 struct uart_port
*port
= &device
->port
;
94 if (uart_parse_earlycon(options
, &port
->iotype
, &addr
, &options
))
97 switch (port
->iotype
) {
103 port
->mapbase
= addr
;
108 port
->mapbase
= addr
;
118 device
->baud
= simple_strtoul(options
, NULL
, 0);
119 length
= min(strcspn(options
, " ") + 1,
120 (size_t)(sizeof(device
->options
)));
121 strlcpy(device
->options
, options
, length
);
127 static int __init
register_earlycon(char *buf
, const struct earlycon_id
*match
)
130 struct uart_port
*port
= &early_console_dev
.port
;
132 /* On parsing error, pass the options buf to the setup function */
133 if (buf
&& !parse_options(&early_console_dev
, buf
))
136 spin_lock_init(&port
->lock
);
137 port
->uartclk
= BASE_BAUD
* 16;
139 port
->membase
= earlycon_map(port
->mapbase
, 64);
141 earlycon_init(&early_console_dev
, match
->name
);
142 err
= match
->setup(&early_console_dev
, buf
);
145 if (!early_console_dev
.con
->write
)
148 register_console(early_console_dev
.con
);
153 * setup_earlycon - match and register earlycon console
154 * @buf: earlycon param string
156 * Registers the earlycon console matching the earlycon specified
157 * in the param string @buf. Acceptable param strings are of the form
158 * <name>,io|mmio|mmio32|mmio32be,<addr>,<options>
159 * <name>,0x<addr>,<options>
163 * Only for the third form does the earlycon setup() method receive the
164 * <options> string in the 'options' parameter; all other forms set
165 * the parameter to NULL.
167 * Returns 0 if an attempt to register the earlycon was made,
168 * otherwise negative error code
170 int __init
setup_earlycon(char *buf
)
172 const struct earlycon_id
**p_match
;
177 if (early_con
.flags
& CON_ENABLED
)
180 for (p_match
= __earlycon_table
; p_match
< __earlycon_table_end
;
182 const struct earlycon_id
*match
= *p_match
;
183 size_t len
= strlen(match
->name
);
185 if (strncmp(buf
, match
->name
, len
))
195 return register_earlycon(buf
, match
);
202 * This defers the initialization of the early console until after ACPI has
205 bool earlycon_acpi_spcr_enable __initdata
;
207 /* early_param wrapper for setup_earlycon() */
208 static int __init
param_setup_earlycon(char *buf
)
212 /* Just 'earlycon' is a valid param for devicetree and ACPI SPCR. */
213 if (!buf
|| !buf
[0]) {
214 if (IS_ENABLED(CONFIG_ACPI_SPCR_TABLE
)) {
215 earlycon_acpi_spcr_enable
= true;
218 return early_init_dt_scan_chosen_stdout();
222 err
= setup_earlycon(buf
);
223 if (err
== -ENOENT
|| err
== -EALREADY
)
227 early_param("earlycon", param_setup_earlycon
);
229 #ifdef CONFIG_OF_EARLY_FLATTREE
231 int __init
of_setup_earlycon(const struct earlycon_id
*match
,
236 struct uart_port
*port
= &early_console_dev
.port
;
241 spin_lock_init(&port
->lock
);
242 port
->iotype
= UPIO_MEM
;
243 addr
= of_flat_dt_translate_address(node
);
244 if (addr
== OF_BAD_ADDR
) {
245 pr_warn("[%s] bad address\n", match
->name
);
248 port
->mapbase
= addr
;
249 port
->uartclk
= BASE_BAUD
* 16;
251 val
= of_get_flat_dt_prop(node
, "reg-offset", NULL
);
253 port
->mapbase
+= be32_to_cpu(*val
);
254 port
->membase
= earlycon_map(port
->mapbase
, SZ_4K
);
256 val
= of_get_flat_dt_prop(node
, "reg-shift", NULL
);
258 port
->regshift
= be32_to_cpu(*val
);
259 big_endian
= of_get_flat_dt_prop(node
, "big-endian", NULL
) != NULL
||
260 (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN
) &&
261 of_get_flat_dt_prop(node
, "native-endian", NULL
) != NULL
);
262 val
= of_get_flat_dt_prop(node
, "reg-io-width", NULL
);
264 switch (be32_to_cpu(*val
)) {
266 port
->iotype
= UPIO_MEM
;
269 port
->iotype
= UPIO_MEM16
;
272 port
->iotype
= (big_endian
) ? UPIO_MEM32BE
: UPIO_MEM32
;
275 pr_warn("[%s] unsupported reg-io-width\n", match
->name
);
280 val
= of_get_flat_dt_prop(node
, "current-speed", NULL
);
282 early_console_dev
.baud
= be32_to_cpu(*val
);
285 early_console_dev
.baud
= simple_strtoul(options
, NULL
, 0);
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 */