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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * coreboot_table.c4 *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_const(d, struct coreboot_driver, drv)26 27static int coreboot_bus_match(struct device *dev, const struct device_driver *drv)28{29 struct coreboot_device *device = CB_DEV(dev);30 const struct coreboot_driver *driver = CB_DRV(drv);31 const struct coreboot_device_id *id;32 33 if (!driver->id_table)34 return 0;35 36 for (id = driver->id_table; id->tag; id++) {37 if (device->entry.tag == id->tag)38 return 1;39 }40 41 return 0;42}43 44static int coreboot_bus_probe(struct device *dev)45{46 int ret = -ENODEV;47 struct coreboot_device *device = CB_DEV(dev);48 struct coreboot_driver *driver = CB_DRV(dev->driver);49 50 if (driver->probe)51 ret = driver->probe(device);52 53 return ret;54}55 56static void coreboot_bus_remove(struct device *dev)57{58 struct coreboot_device *device = CB_DEV(dev);59 struct coreboot_driver *driver = CB_DRV(dev->driver);60 61 if (driver->remove)62 driver->remove(device);63}64 65static int coreboot_bus_uevent(const struct device *dev, struct kobj_uevent_env *env)66{67 struct coreboot_device *device = CB_DEV(dev);68 u32 tag = device->entry.tag;69 70 return add_uevent_var(env, "MODALIAS=coreboot:t%08X", tag);71}72 73static const struct bus_type coreboot_bus_type = {74 .name = "coreboot",75 .match = coreboot_bus_match,76 .probe = coreboot_bus_probe,77 .remove = coreboot_bus_remove,78 .uevent = coreboot_bus_uevent,79};80 81static void coreboot_device_release(struct device *dev)82{83 struct coreboot_device *device = CB_DEV(dev);84 85 kfree(device);86}87 88int __coreboot_driver_register(struct coreboot_driver *driver,89 struct module *owner)90{91 driver->drv.bus = &coreboot_bus_type;92 driver->drv.owner = owner;93 94 return driver_register(&driver->drv);95}96EXPORT_SYMBOL(__coreboot_driver_register);97 98void coreboot_driver_unregister(struct coreboot_driver *driver)99{100 driver_unregister(&driver->drv);101}102EXPORT_SYMBOL(coreboot_driver_unregister);103 104static int coreboot_table_populate(struct device *dev, void *ptr)105{106 int i, ret;107 void *ptr_entry;108 struct coreboot_device *device;109 struct coreboot_table_entry *entry;110 struct coreboot_table_header *header = ptr;111 112 ptr_entry = ptr + header->header_bytes;113 for (i = 0; i < header->table_entries; i++) {114 entry = ptr_entry;115 116 if (entry->size < sizeof(*entry)) {117 dev_warn(dev, "coreboot table entry too small!\n");118 return -EINVAL;119 }120 121 device = kzalloc(sizeof(device->dev) + entry->size, GFP_KERNEL);122 if (!device)123 return -ENOMEM;124 125 device->dev.parent = dev;126 device->dev.bus = &coreboot_bus_type;127 device->dev.release = coreboot_device_release;128 memcpy(device->raw, ptr_entry, entry->size);129 130 switch (device->entry.tag) {131 case LB_TAG_CBMEM_ENTRY:132 dev_set_name(&device->dev, "cbmem-%08x",133 device->cbmem_entry.id);134 break;135 default:136 dev_set_name(&device->dev, "coreboot%d", i);137 break;138 }139 140 ret = device_register(&device->dev);141 if (ret) {142 put_device(&device->dev);143 return ret;144 }145 146 ptr_entry += entry->size;147 }148 149 return 0;150}151 152static int coreboot_table_probe(struct platform_device *pdev)153{154 resource_size_t len;155 struct coreboot_table_header *header;156 struct resource *res;157 struct device *dev = &pdev->dev;158 void *ptr;159 int ret;160 161 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);162 if (!res)163 return -EINVAL;164 165 len = resource_size(res);166 if (!res->start || !len)167 return -EINVAL;168 169 /* Check just the header first to make sure things are sane */170 header = memremap(res->start, sizeof(*header), MEMREMAP_WB);171 if (!header)172 return -ENOMEM;173 174 len = header->header_bytes + header->table_bytes;175 ret = strncmp(header->signature, "LBIO", sizeof(header->signature));176 memunmap(header);177 if (ret) {178 dev_warn(dev, "coreboot table missing or corrupt!\n");179 return -ENODEV;180 }181 182 ptr = memremap(res->start, len, MEMREMAP_WB);183 if (!ptr)184 return -ENOMEM;185 186 ret = coreboot_table_populate(dev, ptr);187 188 memunmap(ptr);189 190 return ret;191}192 193static int __cb_dev_unregister(struct device *dev, void *dummy)194{195 device_unregister(dev);196 return 0;197}198 199static void coreboot_table_remove(struct platform_device *pdev)200{201 bus_for_each_dev(&coreboot_bus_type, NULL, NULL, __cb_dev_unregister);202}203 204#ifdef CONFIG_ACPI205static const struct acpi_device_id cros_coreboot_acpi_match[] = {206 { "GOOGCB00", 0 },207 { "BOOT0000", 0 },208 { }209};210MODULE_DEVICE_TABLE(acpi, cros_coreboot_acpi_match);211#endif212 213#ifdef CONFIG_OF214static const struct of_device_id coreboot_of_match[] = {215 { .compatible = "coreboot" },216 {}217};218MODULE_DEVICE_TABLE(of, coreboot_of_match);219#endif220 221static struct platform_driver coreboot_table_driver = {222 .probe = coreboot_table_probe,223 .remove_new = coreboot_table_remove,224 .driver = {225 .name = "coreboot_table",226 .acpi_match_table = ACPI_PTR(cros_coreboot_acpi_match),227 .of_match_table = of_match_ptr(coreboot_of_match),228 },229};230 231static int __init coreboot_table_driver_init(void)232{233 int ret;234 235 ret = bus_register(&coreboot_bus_type);236 if (ret)237 return ret;238 239 ret = platform_driver_register(&coreboot_table_driver);240 if (ret) {241 bus_unregister(&coreboot_bus_type);242 return ret;243 }244 245 return 0;246}247 248static void __exit coreboot_table_driver_exit(void)249{250 platform_driver_unregister(&coreboot_table_driver);251 bus_unregister(&coreboot_bus_type);252}253 254module_init(coreboot_table_driver_init);255module_exit(coreboot_table_driver_exit);256 257MODULE_AUTHOR("Google, Inc.");258MODULE_DESCRIPTION("Module providing coreboot table access");259MODULE_LICENSE("GPL");260