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.
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>
19 #include <linux/mod_devicetable.h>
21 #ifdef CONFIG_FIX_EARLYCON_MEM
22 #include <asm/fixmap.h>
25 #include <asm/serial.h>
27 static struct console early_con = {
28 .name = "uart", /* 8250 console switch requires this name */
29 .flags = CON_PRINTBUFFER | CON_BOOT,
33 static struct earlycon_device early_console_dev = {
37 static const struct of_device_id __earlycon_of_table_sentinel
38 __used __section(__earlycon_of_table_end);
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 int __init parse_options(struct earlycon_device *device,
60 struct uart_port *port = &device->port;
61 int mmio, mmio32, length;
67 mmio = !strncmp(options, "mmio,", 5);
68 mmio32 = !strncmp(options, "mmio32,", 7);
70 port->iotype = (mmio ? UPIO_MEM : UPIO_MEM32);
71 options += mmio ? 5 : 7;
72 addr = simple_strtoul(options, NULL, 0);
76 } else if (!strncmp(options, "io,", 3)) {
77 port->iotype = UPIO_PORT;
79 addr = simple_strtoul(options, NULL, 0);
82 } else if (!strncmp(options, "0x", 2)) {
83 port->iotype = UPIO_MEM;
84 addr = simple_strtoul(options, NULL, 0);
90 port->uartclk = BASE_BAUD * 16;
92 options = strchr(options, ',');
95 device->baud = simple_strtoul(options, NULL, 0);
96 length = min(strcspn(options, " ") + 1,
97 (size_t)(sizeof(device->options)));
98 strlcpy(device->options, options, length);
101 if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM32)
102 pr_info("Early serial console at MMIO%s 0x%llx (options '%s')\n",
104 (unsigned long long)port->mapbase,
107 pr_info("Early serial console at I/O port 0x%lx (options '%s')\n",
114 int __init setup_earlycon(char *buf, const char *match,
115 int (*setup)(struct earlycon_device *, const char *))
119 struct uart_port *port = &early_console_dev.port;
121 if (!buf || !match || !setup)
125 if (strncmp(buf, match, len))
127 if (buf[len] && (buf[len] != ','))
132 err = parse_options(&early_console_dev, buf);
133 /* On parsing error, pass the options buf to the setup function */
138 port->membase = earlycon_map(port->mapbase, 64);
140 early_console_dev.con->data = &early_console_dev;
141 err = setup(&early_console_dev, buf);
144 if (!early_console_dev.con->write)
147 register_console(early_console_dev.con);
151 int __init of_setup_earlycon(unsigned long addr,
152 int (*setup)(struct earlycon_device *, const char *))
155 struct uart_port *port = &early_console_dev.port;
157 port->iotype = UPIO_MEM;
158 port->mapbase = addr;
159 port->uartclk = BASE_BAUD * 16;
160 port->membase = earlycon_map(addr, SZ_4K);
162 early_console_dev.con->data = &early_console_dev;
163 err = setup(&early_console_dev, NULL);
166 if (!early_console_dev.con->write)
170 register_console(early_console_dev.con);