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
 12static int ecc_size;
 13module_param(ecc_size, int, 0400);
 14MODULE_PARM_DESC(ecc_size, "ECC parity data size in bytes. A positive value enables ECC for the ramoops region.");
 15
 16static const struct dmi_system_id chromeos_pstore_dmi_table[] __initconst = {
 17	{
 18		/*
 19		 * Today all Chromebooks/boxes ship with Google_* as version and
 20		 * coreboot as bios vendor. No other systems with this
 21		 * combination are known to date.
 22		 */
 23		.matches = {
 24			DMI_MATCH(DMI_BIOS_VENDOR, "coreboot"),
 25			DMI_MATCH(DMI_BIOS_VERSION, "Google_"),
 26		},
 27	},
 28	{
 29		/* x86-alex, the first Samsung Chromebook. */
 30		.matches = {
 31			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
 32			DMI_MATCH(DMI_PRODUCT_NAME, "Alex"),
 33		},
 34	},
 35	{
 36		/* x86-mario, the Cr-48 pilot device from Google. */
 37		.matches = {
 38			DMI_MATCH(DMI_SYS_VENDOR, "IEC"),
 39			DMI_MATCH(DMI_PRODUCT_NAME, "Mario"),
 40		},
 41	},
 42	{
 43		/* x86-zgb, the first Acer Chromebook. */
 44		.matches = {
 45			DMI_MATCH(DMI_SYS_VENDOR, "ACER"),
 46			DMI_MATCH(DMI_PRODUCT_NAME, "ZGB"),
 47		},
 48	},
 49	{ }
 50};
 51MODULE_DEVICE_TABLE(dmi, chromeos_pstore_dmi_table);
 52
 53/*
 54 * On x86 chromebooks/boxes, the firmware will keep the legacy VGA memory
 55 * range untouched across reboots, so we use that to store our pstore
 56 * contents for panic logs, etc.
 57 */
 58static struct ramoops_platform_data chromeos_ramoops_data = {
 59	.mem_size	= 0x100000,
 60	.mem_address	= 0xf00000,
 61	.record_size	= 0x40000,
 62	.console_size	= 0x20000,
 63	.ftrace_size	= 0x20000,
 64	.pmsg_size	= 0x20000,
 65	.max_reason	= KMSG_DUMP_OOPS,
 66};
 67
 68static struct platform_device chromeos_ramoops = {
 69	.name = "ramoops",
 70	.dev = {
 71		.platform_data = &chromeos_ramoops_data,
 72	},
 73};
 74
 75#ifdef CONFIG_ACPI
 76static const struct acpi_device_id cros_ramoops_acpi_match[] = {
 77	{ "GOOG9999", 0 },
 78	{ }
 79};
 80MODULE_DEVICE_TABLE(acpi, cros_ramoops_acpi_match);
 81
 82static 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
 89static 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
110static 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
117static inline bool chromeos_check_acpi(void) { return false; }
118#endif
119
120static int __init chromeos_pstore_init(void)
121{
122	bool acpi_dev_found;
123
124	if (ecc_size > 0)
125		chromeos_ramoops_data.ecc_info.ecc_size = ecc_size;
126
127	/* First check ACPI for non-hardcoded values from firmware. */
128	acpi_dev_found = chromeos_check_acpi();
129
130	if (acpi_dev_found || dmi_check_system(chromeos_pstore_dmi_table))
131		return platform_device_register(&chromeos_ramoops);
132
133	return -ENODEV;
134}
135
136static void __exit chromeos_pstore_exit(void)
137{
138	platform_device_unregister(&chromeos_ramoops);
139}
140
141module_init(chromeos_pstore_init);
142module_exit(chromeos_pstore_exit);
143
144MODULE_DESCRIPTION("ChromeOS pstore module");
145MODULE_LICENSE("GPL v2");