Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * coreboot_table.c
4 *
5 * Module providing coreboot table access.
6 *
7 * Copyright 2017 Google Inc.
8 * Copyright 2017 Samuel Holland <samuel@sholland.org>
9 */
10
11#include <linux/acpi.h>
12#include <linux/device.h>
13#include <linux/err.h>
14#include <linux/init.h>
15#include <linux/io.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/of.h>
19#include <linux/platform_device.h>
20#include <linux/slab.h>
21
22#include "coreboot_table.h"
23
24#define CB_DEV(d) container_of(d, struct coreboot_device, dev)
25#define CB_DRV(d) container_of(d, struct coreboot_driver, drv)
26
27static int coreboot_bus_match(struct device *dev, struct device_driver *drv)
28{
29 struct coreboot_device *device = CB_DEV(dev);
30 struct coreboot_driver *driver = CB_DRV(drv);
31
32 return device->entry.tag == driver->tag;
33}
34
35static int coreboot_bus_probe(struct device *dev)
36{
37 int ret = -ENODEV;
38 struct coreboot_device *device = CB_DEV(dev);
39 struct coreboot_driver *driver = CB_DRV(dev->driver);
40
41 if (driver->probe)
42 ret = driver->probe(device);
43
44 return ret;
45}
46
47static int coreboot_bus_remove(struct device *dev)
48{
49 int ret = 0;
50 struct coreboot_device *device = CB_DEV(dev);
51 struct coreboot_driver *driver = CB_DRV(dev->driver);
52
53 if (driver->remove)
54 ret = driver->remove(device);
55
56 return ret;
57}
58
59static struct bus_type coreboot_bus_type = {
60 .name = "coreboot",
61 .match = coreboot_bus_match,
62 .probe = coreboot_bus_probe,
63 .remove = coreboot_bus_remove,
64};
65
66static void coreboot_device_release(struct device *dev)
67{
68 struct coreboot_device *device = CB_DEV(dev);
69
70 kfree(device);
71}
72
73int coreboot_driver_register(struct coreboot_driver *driver)
74{
75 driver->drv.bus = &coreboot_bus_type;
76
77 return driver_register(&driver->drv);
78}
79EXPORT_SYMBOL(coreboot_driver_register);
80
81void coreboot_driver_unregister(struct coreboot_driver *driver)
82{
83 driver_unregister(&driver->drv);
84}
85EXPORT_SYMBOL(coreboot_driver_unregister);
86
87static int coreboot_table_populate(struct device *dev, void *ptr)
88{
89 int i, ret;
90 void *ptr_entry;
91 struct coreboot_device *device;
92 struct coreboot_table_entry *entry;
93 struct coreboot_table_header *header = ptr;
94
95 ptr_entry = ptr + header->header_bytes;
96 for (i = 0; i < header->table_entries; i++) {
97 entry = ptr_entry;
98
99 device = kzalloc(sizeof(struct device) + entry->size, GFP_KERNEL);
100 if (!device)
101 return -ENOMEM;
102
103 dev_set_name(&device->dev, "coreboot%d", i);
104 device->dev.parent = dev;
105 device->dev.bus = &coreboot_bus_type;
106 device->dev.release = coreboot_device_release;
107 memcpy(&device->entry, ptr_entry, entry->size);
108
109 ret = device_register(&device->dev);
110 if (ret) {
111 put_device(&device->dev);
112 return ret;
113 }
114
115 ptr_entry += entry->size;
116 }
117
118 return 0;
119}
120
121static int coreboot_table_probe(struct platform_device *pdev)
122{
123 resource_size_t len;
124 struct coreboot_table_header *header;
125 struct resource *res;
126 struct device *dev = &pdev->dev;
127 void *ptr;
128 int ret;
129
130 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
131 if (!res)
132 return -EINVAL;
133
134 len = resource_size(res);
135 if (!res->start || !len)
136 return -EINVAL;
137
138 /* Check just the header first to make sure things are sane */
139 header = memremap(res->start, sizeof(*header), MEMREMAP_WB);
140 if (!header)
141 return -ENOMEM;
142
143 len = header->header_bytes + header->table_bytes;
144 ret = strncmp(header->signature, "LBIO", sizeof(header->signature));
145 memunmap(header);
146 if (ret) {
147 dev_warn(dev, "coreboot table missing or corrupt!\n");
148 return -ENODEV;
149 }
150
151 ptr = memremap(res->start, len, MEMREMAP_WB);
152 if (!ptr)
153 return -ENOMEM;
154
155 ret = bus_register(&coreboot_bus_type);
156 if (!ret) {
157 ret = coreboot_table_populate(dev, ptr);
158 if (ret)
159 bus_unregister(&coreboot_bus_type);
160 }
161 memunmap(ptr);
162
163 return ret;
164}
165
166static int __cb_dev_unregister(struct device *dev, void *dummy)
167{
168 device_unregister(dev);
169 return 0;
170}
171
172static int coreboot_table_remove(struct platform_device *pdev)
173{
174 bus_for_each_dev(&coreboot_bus_type, NULL, NULL, __cb_dev_unregister);
175 bus_unregister(&coreboot_bus_type);
176 return 0;
177}
178
179#ifdef CONFIG_ACPI
180static const struct acpi_device_id cros_coreboot_acpi_match[] = {
181 { "GOOGCB00", 0 },
182 { "BOOT0000", 0 },
183 { }
184};
185MODULE_DEVICE_TABLE(acpi, cros_coreboot_acpi_match);
186#endif
187
188#ifdef CONFIG_OF
189static const struct of_device_id coreboot_of_match[] = {
190 { .compatible = "coreboot" },
191 {}
192};
193MODULE_DEVICE_TABLE(of, coreboot_of_match);
194#endif
195
196static struct platform_driver coreboot_table_driver = {
197 .probe = coreboot_table_probe,
198 .remove = coreboot_table_remove,
199 .driver = {
200 .name = "coreboot_table",
201 .acpi_match_table = ACPI_PTR(cros_coreboot_acpi_match),
202 .of_match_table = of_match_ptr(coreboot_of_match),
203 },
204};
205module_platform_driver(coreboot_table_driver);
206MODULE_AUTHOR("Google, Inc.");
207MODULE_LICENSE("GPL");