1 // SPDX-License-Identifier: GPL-2.0-only
5 * Module providing coreboot table access.
7 * Copyright 2017 Google Inc.
11 #include <linux/acpi.h>
12 #include <linux/device.h>
13 #include <linux/err.h>
14 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
19 #include <linux/platform_device.h>
20 #include <linux/slab.h>
22 #include "coreboot_table.h"
24 #define CB_DEV(d) container_of(d, struct coreboot_device, dev)
25 #define CB_DRV(d) container_of(d, struct coreboot_driver, drv)
27 static int coreboot_bus_match(struct device *dev, struct device_driver *drv)
29 struct coreboot_device *device = CB_DEV(dev);
30 struct coreboot_driver *driver = CB_DRV(drv);
31 const struct coreboot_device_id *id;
33 if (!driver->id_table)
36 for (id = driver->id_table; id->tag; id++) {
37 if (device->entry.tag == id->tag)
44 static int coreboot_bus_probe(struct device *dev)
47 struct coreboot_device *device = CB_DEV(dev);
48 struct coreboot_driver *driver = CB_DRV(dev->driver);
51 ret = driver->probe(device);
56 static void coreboot_bus_remove(struct device *dev)
58 struct coreboot_device *device = CB_DEV(dev);
59 struct coreboot_driver *driver = CB_DRV(dev->driver);
62 driver->remove(device);
65 static int coreboot_bus_uevent(const struct device *dev, struct kobj_uevent_env *env)
67 struct coreboot_device *device = CB_DEV(dev);
68 u32 tag = device->entry.tag;
70 return add_uevent_var(env, "MODALIAS=coreboot:t%08X", tag);
73 static const struct bus_type coreboot_bus_type = {
75 .match = coreboot_bus_match,
76 .probe = coreboot_bus_probe,
77 .remove = coreboot_bus_remove,
78 .uevent = coreboot_bus_uevent,
81 static void coreboot_device_release(struct device *dev)
83 struct coreboot_device *device = CB_DEV(dev);
88 int coreboot_driver_register(struct coreboot_driver *driver)
90 driver->drv.bus = &coreboot_bus_type;
92 return driver_register(&driver->drv);
94 EXPORT_SYMBOL(coreboot_driver_register);
96 void coreboot_driver_unregister(struct coreboot_driver *driver)
98 driver_unregister(&driver->drv);
100 EXPORT_SYMBOL(coreboot_driver_unregister);
102 static int coreboot_table_populate(struct device *dev, void *ptr)
106 struct coreboot_device *device;
107 struct coreboot_table_entry *entry;
108 struct coreboot_table_header *header = ptr;
110 ptr_entry = ptr + header->header_bytes;
111 for (i = 0; i < header->table_entries; i++) {
114 if (entry->size < sizeof(*entry)) {
115 dev_warn(dev, "coreboot table entry too small!\n");
119 device = kzalloc(sizeof(device->dev) + entry->size, GFP_KERNEL);
123 device->dev.parent = dev;
124 device->dev.bus = &coreboot_bus_type;
125 device->dev.release = coreboot_device_release;
126 memcpy(device->raw, ptr_entry, entry->size);
128 switch (device->entry.tag) {
129 case LB_TAG_CBMEM_ENTRY:
130 dev_set_name(&device->dev, "cbmem-%08x",
131 device->cbmem_entry.id);
134 dev_set_name(&device->dev, "coreboot%d", i);
138 ret = device_register(&device->dev);
140 put_device(&device->dev);
144 ptr_entry += entry->size;
150 static int coreboot_table_probe(struct platform_device *pdev)
153 struct coreboot_table_header *header;
154 struct resource *res;
155 struct device *dev = &pdev->dev;
159 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
163 len = resource_size(res);
164 if (!res->start || !len)
167 /* Check just the header first to make sure things are sane */
168 header = memremap(res->start, sizeof(*header), MEMREMAP_WB);
172 len = header->header_bytes + header->table_bytes;
173 ret = strncmp(header->signature, "LBIO", sizeof(header->signature));
176 dev_warn(dev, "coreboot table missing or corrupt!\n");
180 ptr = memremap(res->start, len, MEMREMAP_WB);
184 ret = coreboot_table_populate(dev, ptr);
191 static int __cb_dev_unregister(struct device *dev, void *dummy)
193 device_unregister(dev);
197 static void coreboot_table_remove(struct platform_device *pdev)
199 bus_for_each_dev(&coreboot_bus_type, NULL, NULL, __cb_dev_unregister);
203 static const struct acpi_device_id cros_coreboot_acpi_match[] = {
208 MODULE_DEVICE_TABLE(acpi, cros_coreboot_acpi_match);
212 static const struct of_device_id coreboot_of_match[] = {
213 { .compatible = "coreboot" },
216 MODULE_DEVICE_TABLE(of, coreboot_of_match);
219 static struct platform_driver coreboot_table_driver = {
220 .probe = coreboot_table_probe,
221 .remove_new = coreboot_table_remove,
223 .name = "coreboot_table",
224 .acpi_match_table = ACPI_PTR(cros_coreboot_acpi_match),
225 .of_match_table = of_match_ptr(coreboot_of_match),
229 static int __init coreboot_table_driver_init(void)
233 ret = bus_register(&coreboot_bus_type);
237 ret = platform_driver_register(&coreboot_table_driver);
239 bus_unregister(&coreboot_bus_type);
246 static void __exit coreboot_table_driver_exit(void)
248 platform_driver_unregister(&coreboot_table_driver);
249 bus_unregister(&coreboot_bus_type);
252 module_init(coreboot_table_driver_init);
253 module_exit(coreboot_table_driver_exit);
255 MODULE_AUTHOR("Google, Inc.");
256 MODULE_LICENSE("GPL");