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");