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 	.dump_oops	= 1,
61 };
62 
63 static struct platform_device chromeos_ramoops = {
64 	.name = "ramoops",
65 	.dev = {
66 		.platform_data = &chromeos_ramoops_data,
67 	},
68 };
69 
70 #ifdef CONFIG_ACPI
71 static const struct acpi_device_id cros_ramoops_acpi_match[] = {
72 	{ "GOOG9999", 0 },
73 	{ }
74 };
75 MODULE_DEVICE_TABLE(acpi, cros_ramoops_acpi_match);
76 
77 static struct platform_driver chromeos_ramoops_acpi = {
78 	.driver		= {
79 		.name	= "chromeos_pstore",
80 		.acpi_match_table = ACPI_PTR(cros_ramoops_acpi_match),
81 	},
82 };
83 
84 static int __init chromeos_probe_acpi(struct platform_device *pdev)
85 {
86 	struct resource *res;
87 	resource_size_t len;
88 
89 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
90 	if (!res)
91 		return -ENOMEM;
92 
93 	len = resource_size(res);
94 	if (!res->start || !len)
95 		return -ENOMEM;
96 
97 	pr_info("chromeos ramoops using acpi device.\n");
98 
99 	chromeos_ramoops_data.mem_size = len;
100 	chromeos_ramoops_data.mem_address = res->start;
101 
102 	return 0;
103 }
104 
105 static bool __init chromeos_check_acpi(void)
106 {
107 	if (!platform_driver_probe(&chromeos_ramoops_acpi, chromeos_probe_acpi))
108 		return true;
109 	return false;
110 }
111 #else
112 static inline bool chromeos_check_acpi(void) { return false; }
113 #endif
114 
115 static int __init chromeos_pstore_init(void)
116 {
117 	bool acpi_dev_found;
118 
119 	/* First check ACPI for non-hardcoded values from firmware. */
120 	acpi_dev_found = chromeos_check_acpi();
121 
122 	if (acpi_dev_found || dmi_check_system(chromeos_pstore_dmi_table))
123 		return platform_device_register(&chromeos_ramoops);
124 
125 	return -ENODEV;
126 }
127 
128 static void __exit chromeos_pstore_exit(void)
129 {
130 	platform_device_unregister(&chromeos_ramoops);
131 }
132 
133 module_init(chromeos_pstore_init);
134 module_exit(chromeos_pstore_exit);
135 
136 MODULE_DESCRIPTION("ChromeOS pstore module");
137 MODULE_LICENSE("GPL v2");
138