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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * coreboot_table.c
- *
- * Module providing coreboot table access.
- *
- * Copyright 2017 Google Inc.
- * Copyright 2017 Samuel Holland <samuel@sholland.org>
- */
- #include <linux/acpi.h>
- #include <linux/device.h>
- #include <linux/err.h>
- #include <linux/init.h>
- #include <linux/io.h>
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/of.h>
- #include <linux/platform_device.h>
- #include <linux/slab.h>
- #include "coreboot_table.h"
- #define CB_DEV(d) container_of(d, struct coreboot_device, dev)
- #define CB_DRV(d) container_of(d, struct coreboot_driver, drv)
- static int coreboot_bus_match(struct device *dev, struct device_driver *drv)
- {
- struct coreboot_device *device = CB_DEV(dev);
- struct coreboot_driver *driver = CB_DRV(drv);
- return device->entry.tag == driver->tag;
- }
- static int coreboot_bus_probe(struct device *dev)
- {
- int ret = -ENODEV;
- struct coreboot_device *device = CB_DEV(dev);
- struct coreboot_driver *driver = CB_DRV(dev->driver);
- if (driver->probe)
- ret = driver->probe(device);
- return ret;
- }
- static int coreboot_bus_remove(struct device *dev)
- {
- int ret = 0;
- struct coreboot_device *device = CB_DEV(dev);
- struct coreboot_driver *driver = CB_DRV(dev->driver);
- if (driver->remove)
- ret = driver->remove(device);
- return ret;
- }
- static struct bus_type coreboot_bus_type = {
- .name = "coreboot",
- .match = coreboot_bus_match,
- .probe = coreboot_bus_probe,
- .remove = coreboot_bus_remove,
- };
- static void coreboot_device_release(struct device *dev)
- {
- struct coreboot_device *device = CB_DEV(dev);
- kfree(device);
- }
- int coreboot_driver_register(struct coreboot_driver *driver)
- {
- driver->drv.bus = &coreboot_bus_type;
- return driver_register(&driver->drv);
- }
- EXPORT_SYMBOL(coreboot_driver_register);
- void coreboot_driver_unregister(struct coreboot_driver *driver)
- {
- driver_unregister(&driver->drv);
- }
- EXPORT_SYMBOL(coreboot_driver_unregister);
- static int coreboot_table_populate(struct device *dev, void *ptr)
- {
- int i, ret;
- void *ptr_entry;
- struct coreboot_device *device;
- struct coreboot_table_entry *entry;
- struct coreboot_table_header *header = ptr;
- ptr_entry = ptr + header->header_bytes;
- for (i = 0; i < header->table_entries; i++) {
- entry = ptr_entry;
- device = kzalloc(sizeof(struct device) + entry->size, GFP_KERNEL);
- if (!device)
- return -ENOMEM;
- dev_set_name(&device->dev, "coreboot%d", i);
- device->dev.parent = dev;
- device->dev.bus = &coreboot_bus_type;
- device->dev.release = coreboot_device_release;
- memcpy(&device->entry, ptr_entry, entry->size);
- ret = device_register(&device->dev);
- if (ret) {
- put_device(&device->dev);
- return ret;
- }
- ptr_entry += entry->size;
- }
- return 0;
- }
- static int coreboot_table_probe(struct platform_device *pdev)
- {
- resource_size_t len;
- struct coreboot_table_header *header;
- struct resource *res;
- struct device *dev = &pdev->dev;
- void *ptr;
- int ret;
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!res)
- return -EINVAL;
- len = resource_size(res);
- if (!res->start || !len)
- return -EINVAL;
- /* Check just the header first to make sure things are sane */
- header = memremap(res->start, sizeof(*header), MEMREMAP_WB);
- if (!header)
- return -ENOMEM;
- len = header->header_bytes + header->table_bytes;
- ret = strncmp(header->signature, "LBIO", sizeof(header->signature));
- memunmap(header);
- if (ret) {
- dev_warn(dev, "coreboot table missing or corrupt!\n");
- return -ENODEV;
- }
- ptr = memremap(res->start, len, MEMREMAP_WB);
- if (!ptr)
- return -ENOMEM;
- ret = bus_register(&coreboot_bus_type);
- if (!ret) {
- ret = coreboot_table_populate(dev, ptr);
- if (ret)
- bus_unregister(&coreboot_bus_type);
- }
- memunmap(ptr);
- return ret;
- }
- static int __cb_dev_unregister(struct device *dev, void *dummy)
- {
- device_unregister(dev);
- return 0;
- }
- static int coreboot_table_remove(struct platform_device *pdev)
- {
- bus_for_each_dev(&coreboot_bus_type, NULL, NULL, __cb_dev_unregister);
- bus_unregister(&coreboot_bus_type);
- return 0;
- }
- #ifdef CONFIG_ACPI
- static const struct acpi_device_id cros_coreboot_acpi_match[] = {
- { "GOOGCB00", 0 },
- { "BOOT0000", 0 },
- { }
- };
- MODULE_DEVICE_TABLE(acpi, cros_coreboot_acpi_match);
- #endif
- #ifdef CONFIG_OF
- static const struct of_device_id coreboot_of_match[] = {
- { .compatible = "coreboot" },
- {}
- };
- MODULE_DEVICE_TABLE(of, coreboot_of_match);
- #endif
- static struct platform_driver coreboot_table_driver = {
- .probe = coreboot_table_probe,
- .remove = coreboot_table_remove,
- .driver = {
- .name = "coreboot_table",
- .acpi_match_table = ACPI_PTR(cros_coreboot_acpi_match),
- .of_match_table = of_match_ptr(coreboot_of_match),
- },
- };
- module_platform_driver(coreboot_table_driver);
- MODULE_AUTHOR("Google, Inc.");
- MODULE_LICENSE("GPL");
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