Merge tag 'platform-drivers-x86-v4.20-1' of git://git.infradead.org/linux-platform...
[sfrench/cifs-2.6.git] / drivers / platform / chrome / chromeos_pstore.c
1 /*
2  *  chromeos_pstore.c - Driver to instantiate Chromebook ramoops device
3  *
4  *  Copyright (C) 2013 Google, Inc.
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation, version 2 of the License.
9  */
10
11 #include <linux/acpi.h>
12 #include <linux/dmi.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/pstore_ram.h>
16
17 static const struct dmi_system_id chromeos_pstore_dmi_table[] __initconst = {
18         {
19                 /*
20                  * Today all Chromebooks/boxes ship with Google_* as version and
21                  * coreboot as bios vendor. No other systems with this
22                  * combination are known to date.
23                  */
24                 .matches = {
25                         DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
26                         DMI_MATCH(DMI_BIOS_VERSION, "Google_"),
27                 },
28         },
29         {
30                 /* x86-alex, the first Samsung Chromebook. */
31                 .matches = {
32                         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
33                         DMI_MATCH(DMI_PRODUCT_NAME, "Alex"),
34                 },
35         },
36         {
37                 /* x86-mario, the Cr-48 pilot device from Google. */
38                 .matches = {
39                         DMI_MATCH(DMI_SYS_VENDOR, "IEC"),
40                         DMI_MATCH(DMI_PRODUCT_NAME, "Mario"),
41                 },
42         },
43         {
44                 /* x86-zgb, the first Acer Chromebook. */
45                 .matches = {
46                         DMI_MATCH(DMI_SYS_VENDOR, "ACER"),
47                         DMI_MATCH(DMI_PRODUCT_NAME, "ZGB"),
48                 },
49         },
50         { }
51 };
52 MODULE_DEVICE_TABLE(dmi, chromeos_pstore_dmi_table);
53
54 /*
55  * On x86 chromebooks/boxes, the firmware will keep the legacy VGA memory
56  * range untouched across reboots, so we use that to store our pstore
57  * contents for panic logs, etc.
58  */
59 static struct ramoops_platform_data chromeos_ramoops_data = {
60         .mem_size       = 0x100000,
61         .mem_address    = 0xf00000,
62         .record_size    = 0x40000,
63         .console_size   = 0x20000,
64         .ftrace_size    = 0x20000,
65         .dump_oops      = 1,
66 };
67
68 static struct platform_device chromeos_ramoops = {
69         .name = "ramoops",
70         .dev = {
71                 .platform_data = &chromeos_ramoops_data,
72         },
73 };
74
75 #ifdef CONFIG_ACPI
76 static const struct acpi_device_id cros_ramoops_acpi_match[] = {
77         { "GOOG9999", 0 },
78         { }
79 };
80 MODULE_DEVICE_TABLE(acpi, cros_ramoops_acpi_match);
81
82 static struct platform_driver chromeos_ramoops_acpi = {
83         .driver         = {
84                 .name   = "chromeos_pstore",
85                 .acpi_match_table = ACPI_PTR(cros_ramoops_acpi_match),
86         },
87 };
88
89 static int __init chromeos_probe_acpi(struct platform_device *pdev)
90 {
91         struct resource *res;
92         resource_size_t len;
93
94         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
95         if (!res)
96                 return -ENOMEM;
97
98         len = resource_size(res);
99         if (!res->start || !len)
100                 return -ENOMEM;
101
102         pr_info("chromeos ramoops using acpi device.\n");
103
104         chromeos_ramoops_data.mem_size = len;
105         chromeos_ramoops_data.mem_address = res->start;
106
107         return 0;
108 }
109
110 static bool __init chromeos_check_acpi(void)
111 {
112         if (!platform_driver_probe(&chromeos_ramoops_acpi, chromeos_probe_acpi))
113                 return true;
114         return false;
115 }
116 #else
117 static inline bool chromeos_check_acpi(void) { return false; }
118 #endif
119
120 static int __init chromeos_pstore_init(void)
121 {
122         bool acpi_dev_found;
123
124         /* First check ACPI for non-hardcoded values from firmware. */
125         acpi_dev_found = chromeos_check_acpi();
126
127         if (acpi_dev_found || dmi_check_system(chromeos_pstore_dmi_table))
128                 return platform_device_register(&chromeos_ramoops);
129
130         return -ENODEV;
131 }
132
133 static void __exit chromeos_pstore_exit(void)
134 {
135         platform_device_unregister(&chromeos_ramoops);
136 }
137
138 module_init(chromeos_pstore_init);
139 module_exit(chromeos_pstore_exit);
140
141 MODULE_DESCRIPTION("Chrome OS pstore module");
142 MODULE_LICENSE("GPL");