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 
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 
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 
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 
73 static int __init coreboot_bus_init(void)
74 {
75 	return bus_register(&coreboot_bus_type);
76 }
77 module_init(coreboot_bus_init);
78 
79 static void coreboot_device_release(struct device *dev)
80 {
81 	struct coreboot_device *device = CB_DEV(dev);
82 
83 	kfree(device);
84 }
85 
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 
94 void coreboot_driver_unregister(struct coreboot_driver *driver)
95 {
96 	driver_unregister(&driver->drv);
97 }
98 EXPORT_SYMBOL(coreboot_driver_unregister);
99 
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 
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