1 /*
2 * coreboot_table.c
3 *
4 * Module providing coreboot table access.
5 *
6 * Copyright 2017 Google Inc.
7 * Copyright 2017 Samuel Holland <samuel@sholland.org>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License v2.0 as published by
11 * the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 */
18
19 #include <linux/device.h>
20 #include <linux/err.h>
21 #include <linux/init.h>
22 #include <linux/io.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/slab.h>
26
27 #include "coreboot_table.h"
28
29 #define CB_DEV(d) container_of(d, struct coreboot_device, dev)
30 #define CB_DRV(d) container_of(d, struct coreboot_driver, drv)
31
32 static struct coreboot_table_header __iomem *ptr_header;
33
coreboot_bus_match(struct device * dev,struct device_driver * drv)34 static int coreboot_bus_match(struct device *dev, struct device_driver *drv)
35 {
36 struct coreboot_device *device = CB_DEV(dev);
37 struct coreboot_driver *driver = CB_DRV(drv);
38
39 return device->entry.tag == driver->tag;
40 }
41
coreboot_bus_probe(struct device * dev)42 static int coreboot_bus_probe(struct device *dev)
43 {
44 int ret = -ENODEV;
45 struct coreboot_device *device = CB_DEV(dev);
46 struct coreboot_driver *driver = CB_DRV(dev->driver);
47
48 if (driver->probe)
49 ret = driver->probe(device);
50
51 return ret;
52 }
53
coreboot_bus_remove(struct device * dev)54 static int coreboot_bus_remove(struct device *dev)
55 {
56 int ret = 0;
57 struct coreboot_device *device = CB_DEV(dev);
58 struct coreboot_driver *driver = CB_DRV(dev->driver);
59
60 if (driver->remove)
61 ret = driver->remove(device);
62
63 return ret;
64 }
65
66 static struct bus_type coreboot_bus_type = {
67 .name = "coreboot",
68 .match = coreboot_bus_match,
69 .probe = coreboot_bus_probe,
70 .remove = coreboot_bus_remove,
71 };
72
coreboot_bus_init(void)73 static int __init coreboot_bus_init(void)
74 {
75 return bus_register(&coreboot_bus_type);
76 }
77 module_init(coreboot_bus_init);
78
coreboot_device_release(struct device * dev)79 static void coreboot_device_release(struct device *dev)
80 {
81 struct coreboot_device *device = CB_DEV(dev);
82
83 kfree(device);
84 }
85
coreboot_driver_register(struct coreboot_driver * driver)86 int coreboot_driver_register(struct coreboot_driver *driver)
87 {
88 driver->drv.bus = &coreboot_bus_type;
89
90 return driver_register(&driver->drv);
91 }
92 EXPORT_SYMBOL(coreboot_driver_register);
93
coreboot_driver_unregister(struct coreboot_driver * driver)94 void coreboot_driver_unregister(struct coreboot_driver *driver)
95 {
96 driver_unregister(&driver->drv);
97 }
98 EXPORT_SYMBOL(coreboot_driver_unregister);
99
coreboot_table_init(struct device * dev,void __iomem * ptr)100 int coreboot_table_init(struct device *dev, void __iomem *ptr)
101 {
102 int i, ret;
103 void *ptr_entry;
104 struct coreboot_device *device;
105 struct coreboot_table_entry entry;
106 struct coreboot_table_header header;
107
108 ptr_header = ptr;
109 memcpy_fromio(&header, ptr_header, sizeof(header));
110
111 if (strncmp(header.signature, "LBIO", sizeof(header.signature))) {
112 pr_warn("coreboot_table: coreboot table missing or corrupt!\n");
113 return -ENODEV;
114 }
115
116 ptr_entry = (void *)ptr_header + header.header_bytes;
117 for (i = 0; i < header.table_entries; i++) {
118 memcpy_fromio(&entry, ptr_entry, sizeof(entry));
119
120 device = kzalloc(sizeof(struct device) + entry.size, GFP_KERNEL);
121 if (!device) {
122 ret = -ENOMEM;
123 break;
124 }
125
126 dev_set_name(&device->dev, "coreboot%d", i);
127 device->dev.parent = dev;
128 device->dev.bus = &coreboot_bus_type;
129 device->dev.release = coreboot_device_release;
130 memcpy_fromio(&device->entry, ptr_entry, entry.size);
131
132 ret = device_register(&device->dev);
133 if (ret) {
134 put_device(&device->dev);
135 break;
136 }
137
138 ptr_entry += entry.size;
139 }
140
141 return ret;
142 }
143 EXPORT_SYMBOL(coreboot_table_init);
144
coreboot_table_exit(void)145 int coreboot_table_exit(void)
146 {
147 if (ptr_header) {
148 bus_unregister(&coreboot_bus_type);
149 iounmap(ptr_header);
150 ptr_header = NULL;
151 }
152
153 return 0;
154 }
155 EXPORT_SYMBOL(coreboot_table_exit);
156
157 MODULE_AUTHOR("Google, Inc.");
158 MODULE_LICENSE("GPL");
159
