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 
chromeos_probe_acpi(struct platform_device * pdev)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 
chromeos_check_acpi(void)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
chromeos_check_acpi(void)113 static inline bool chromeos_check_acpi(void) { return false; }
114 #endif
115 
chromeos_pstore_init(void)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 
chromeos_pstore_exit(void)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");
139