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1 | /* |
2 | * Copyright (C) 2014 Linaro Ltd. | |
3 | * Author: Rob Herring <robh@kernel.org> | |
4 | * | |
5 | * Based on 8250 earlycon: | |
6 | * (c) Copyright 2004 Hewlett-Packard Development Company, L.P. | |
7 | * Bjorn Helgaas <bjorn.helgaas@hp.com> | |
8 | * | |
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. | |
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 | ||
19 | #ifdef CONFIG_FIX_EARLYCON_MEM | |
20 | #include <asm/fixmap.h> | |
21 | #endif | |
22 | ||
23 | #include <asm/serial.h> | |
24 | ||
25 | static struct console early_con = { | |
26 | .name = "earlycon", | |
27 | .flags = CON_PRINTBUFFER | CON_BOOT, | |
28 | .index = -1, | |
29 | }; | |
30 | ||
31 | static struct earlycon_device early_console_dev = { | |
32 | .con = &early_con, | |
33 | }; | |
34 | ||
35 | static void __iomem * __init earlycon_map(unsigned long paddr, size_t size) | |
36 | { | |
37 | void __iomem *base; | |
38 | #ifdef CONFIG_FIX_EARLYCON_MEM | |
39 | set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr & PAGE_MASK); | |
40 | base = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE); | |
41 | base += paddr & ~PAGE_MASK; | |
42 | #else | |
43 | base = ioremap(paddr, size); | |
44 | #endif | |
45 | if (!base) | |
46 | pr_err("%s: Couldn't map 0x%llx\n", __func__, | |
47 | (unsigned long long)paddr); | |
48 | ||
49 | return base; | |
50 | } | |
51 | ||
52 | static int __init parse_options(struct earlycon_device *device, | |
53 | char *options) | |
54 | { | |
55 | struct uart_port *port = &device->port; | |
56 | int mmio, mmio32, length, ret; | |
57 | unsigned long addr; | |
58 | ||
59 | if (!options) | |
60 | return -ENODEV; | |
61 | ||
62 | mmio = !strncmp(options, "mmio,", 5); | |
63 | mmio32 = !strncmp(options, "mmio32,", 7); | |
64 | if (mmio || mmio32) { | |
65 | port->iotype = (mmio ? UPIO_MEM : UPIO_MEM32); | |
66 | options += mmio ? 5 : 7; | |
67 | ret = kstrtoul(options, 0, &addr); | |
68 | if (ret) | |
69 | return ret; | |
70 | port->mapbase = addr; | |
71 | if (mmio32) | |
72 | port->regshift = 2; | |
73 | } else if (!strncmp(options, "io,", 3)) { | |
74 | port->iotype = UPIO_PORT; | |
75 | options += 3; | |
76 | ret = kstrtoul(options, 0, &addr); | |
77 | if (ret) | |
78 | return ret; | |
79 | port->iobase = addr; | |
80 | mmio = 0; | |
81 | } else if (!strncmp(options, "0x", 2)) { | |
82 | port->iotype = UPIO_MEM; | |
83 | ret = kstrtoul(options, 0, &addr); | |
84 | if (ret) | |
85 | return ret; | |
86 | port->mapbase = addr; | |
87 | } else { | |
88 | return -EINVAL; | |
89 | } | |
90 | ||
91 | port->uartclk = BASE_BAUD * 16; | |
92 | ||
93 | options = strchr(options, ','); | |
94 | if (options) { | |
95 | options++; | |
96 | ret = kstrtouint(options, 0, &device->baud); | |
97 | if (ret) | |
98 | return ret; | |
99 | length = min(strcspn(options, " ") + 1, | |
100 | (size_t)(sizeof(device->options))); | |
101 | strlcpy(device->options, options, length); | |
102 | } | |
103 | ||
104 | if (mmio || mmio32) | |
105 | pr_info("Early serial console at MMIO%s 0x%llx (options '%s')\n", | |
106 | mmio32 ? "32" : "", | |
107 | (unsigned long long)port->mapbase, | |
108 | device->options); | |
109 | else | |
110 | pr_info("Early serial console at I/O port 0x%lx (options '%s')\n", | |
111 | port->iobase, | |
112 | device->options); | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | int __init setup_earlycon(char *buf, const char *match, | |
118 | int (*setup)(struct earlycon_device *, const char *)) | |
119 | { | |
120 | int err; | |
121 | size_t len; | |
122 | struct uart_port *port = &early_console_dev.port; | |
123 | ||
124 | if (!buf || !match || !setup) | |
125 | return 0; | |
126 | ||
127 | len = strlen(match); | |
128 | if (strncmp(buf, match, len)) | |
129 | return 0; | |
130 | if (buf[len] && (buf[len] != ',')) | |
131 | return 0; | |
132 | ||
133 | buf += len + 1; | |
134 | ||
135 | err = parse_options(&early_console_dev, buf); | |
136 | /* On parsing error, pass the options buf to the setup function */ | |
137 | if (!err) | |
138 | buf = NULL; | |
139 | ||
140 | if (port->mapbase) | |
141 | port->membase = earlycon_map(port->mapbase, 64); | |
142 | ||
143 | early_console_dev.con->data = &early_console_dev; | |
144 | err = setup(&early_console_dev, buf); | |
145 | if (err < 0) | |
146 | return err; | |
147 | if (!early_console_dev.con->write) | |
148 | return -ENODEV; | |
149 | ||
150 | register_console(early_console_dev.con); | |
151 | return 0; | |
152 | } |