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 int ecc_size;
13 module_param(ecc_size, int, 0400);
14 MODULE_PARM_DESC(ecc_size, "ECC parity data size in bytes. A positive value enables ECC for the ramoops region.");
15
16 static 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 };
51 MODULE_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 */
58 static 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
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
chromeos_probe_acpi(struct platform_device * pdev)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
chromeos_check_acpi(void)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
chromeos_check_acpi(void)117 static inline bool chromeos_check_acpi(void) { return false; }
118 #endif
119
chromeos_pstore_init(void)120 static 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
chromeos_pstore_exit(void)136 static void __exit chromeos_pstore_exit(void)
137 {
138 platform_device_unregister(&chromeos_ramoops);
139 }
140
141 module_init(chromeos_pstore_init);
142 module_exit(chromeos_pstore_exit);
143
144 MODULE_DESCRIPTION("ChromeOS pstore module");
145 MODULE_LICENSE("GPL v2");
146