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 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};
47MODULE_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 */
54static 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
64static struct platform_device chromeos_ramoops = {
65	.name = "ramoops",
66	.dev = {
67		.platform_data = &chromeos_ramoops_data,
68	},
69};
70
71#ifdef CONFIG_ACPI
72static const struct acpi_device_id cros_ramoops_acpi_match[] = {
73	{ "GOOG9999", 0 },
74	{ }
75};
76MODULE_DEVICE_TABLE(acpi, cros_ramoops_acpi_match);
77
78static 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
85static 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
106static 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
113static inline bool chromeos_check_acpi(void) { return false; }
114#endif
115
116static 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
129static void __exit chromeos_pstore_exit(void)
130{
131	platform_device_unregister(&chromeos_ramoops);
132}
133
134module_init(chromeos_pstore_init);
135module_exit(chromeos_pstore_exit);
136
137MODULE_DESCRIPTION("ChromeOS pstore module");
138MODULE_LICENSE("GPL v2");
139