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");
143