drivers/platform/chrome/chromeos_pstore.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Driver to instantiate Chromebook ramoops device.
   3 //
   4 // Copyright (C) 2013 Google, Inc.
   5
   6 #include <linux/acpi.h>
   7 #include <linux/dmi.h>
   8 #include <linux/module.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/pstore_ram.h>
  11
  12 static const struct dmi_system_id chromeos_pstore_dmi_table[] __initconst = {
  13         {
  14                 /*
  15                  * Today all Chromebooks/boxes ship with Google_* as version and
  16                  * coreboot as bios vendor. No other systems with this
  17                  * combination are known to date.
  18                  */
  19                 .matches = {
  20                         DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
  21                         DMI_MATCH(DMI_BIOS_VERSION, "Google_"),
  22                 },
  23         },
  24         {
  25                 /* x86-alex, the first Samsung Chromebook. */
  26                 .matches = {
  27                         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
  28                         DMI_MATCH(DMI_PRODUCT_NAME, "Alex"),
  29                 },
  30         },
  31         {
  32                 /* x86-mario, the Cr-48 pilot device from Google. */
  33                 .matches = {
  34                         DMI_MATCH(DMI_SYS_VENDOR, "IEC"),
  35                         DMI_MATCH(DMI_PRODUCT_NAME, "Mario"),
  36                 },
  37         },
  38         {
  39                 /* x86-zgb, the first Acer Chromebook. */
  40                 .matches = {
  41                         DMI_MATCH(DMI_SYS_VENDOR, "ACER"),
  42                         DMI_MATCH(DMI_PRODUCT_NAME, "ZGB"),
  43                 },
  44         },
  45         { }
  46 };
  47 MODULE_DEVICE_TABLE(dmi, chromeos_pstore_dmi_table);
  48
  49 /*
  50  * On x86 chromebooks/boxes, the firmware will keep the legacy VGA memory
  51  * range untouched across reboots, so we use that to store our pstore
  52  * contents for panic logs, etc.
  53  */
  54 static struct ramoops_platform_data chromeos_ramoops_data = {
  55         .mem_size       = 0x100000,
  56         .mem_address    = 0xf00000,
  57         .record_size    = 0x40000,
  58         .console_size   = 0x20000,
  59         .ftrace_size    = 0x20000,
  60         .pmsg_size      = 0x20000,
  61         .max_reason     = KMSG_DUMP_OOPS,
  62 };
  63
  64 static struct platform_device chromeos_ramoops = {
  65         .name = "ramoops",
  66         .dev = {
  67                 .platform_data = &chromeos_ramoops_data,
  68         },
  69 };
  70
  71 #ifdef CONFIG_ACPI
  72 static const struct acpi_device_id cros_ramoops_acpi_match[] = {
  73         { "GOOG9999", 0 },
  74         { }
  75 };
  76 MODULE_DEVICE_TABLE(acpi, cros_ramoops_acpi_match);
  77
  78 static struct platform_driver chromeos_ramoops_acpi = {
  79         .driver         = {
  80                 .name   = "chromeos_pstore",
  81                 .acpi_match_table = ACPI_PTR(cros_ramoops_acpi_match),
  82         },
  83 };
  84
  85 static int __init chromeos_probe_acpi(struct platform_device *pdev)
  86 {
  87         struct resource *res;
  88         resource_size_t len;
  89
  90         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  91         if (!res)
  92                 return -ENOMEM;
  93
  94         len = resource_size(res);
  95         if (!res->start || !len)
  96                 return -ENOMEM;
  97
  98         pr_info("chromeos ramoops using acpi device.\n");
  99
 100         chromeos_ramoops_data.mem_size = len;
 101         chromeos_ramoops_data.mem_address = res->start;
 102
 103         return 0;
 104 }
 105
 106 static bool __init chromeos_check_acpi(void)
 107 {
 108         if (!platform_driver_probe(&chromeos_ramoops_acpi, chromeos_probe_acpi))
 109                 return true;
 110         return false;
 111 }
 112 #else
 113 static inline bool chromeos_check_acpi(void) { return false; }
 114 #endif
 115
 116 static int __init chromeos_pstore_init(void)
 117 {
 118         bool acpi_dev_found;
 119
 120         /* First check ACPI for non-hardcoded values from firmware. */
 121         acpi_dev_found = chromeos_check_acpi();
 122
 123         if (acpi_dev_found || dmi_check_system(chromeos_pstore_dmi_table))
 124                 return platform_device_register(&chromeos_ramoops);
 125
 126         return -ENODEV;
 127 }
 128
 129 static void __exit chromeos_pstore_exit(void)
 130 {
 131         platform_device_unregister(&chromeos_ramoops);
 132 }
 133
 134 module_init(chromeos_pstore_init);
 135 module_exit(chromeos_pstore_exit);
 136
 137 MODULE_DESCRIPTION("ChromeOS pstore module");
 138 MODULE_LICENSE("GPL v2");