// SPDX-License-Identifier: GPL-2.0-only /* * coreboot_table.c * * Module providing coreboot table access. * * Copyright 2017 Google Inc. * Copyright 2017 Samuel Holland */ #include #include #include #include #include #include #include #include #include #include #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); const struct coreboot_device_id *id; if (!driver->id_table) return 0; for (id = driver->id_table; id->tag; id++) { if (device->entry.tag == id->tag) return 1; } return 0; } 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 void coreboot_bus_remove(struct device *dev) { struct coreboot_device *device = CB_DEV(dev); struct coreboot_driver *driver = CB_DRV(dev->driver); if (driver->remove) driver->remove(device); } static int coreboot_bus_uevent(const struct device *dev, struct kobj_uevent_env *env) { struct coreboot_device *device = CB_DEV(dev); u32 tag = device->entry.tag; return add_uevent_var(env, "MODALIAS=coreboot:t%08X", tag); } static const struct bus_type coreboot_bus_type = { .name = "coreboot", .match = coreboot_bus_match, .probe = coreboot_bus_probe, .remove = coreboot_bus_remove, .uevent = coreboot_bus_uevent, }; 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, struct module *owner) { driver->drv.bus = &coreboot_bus_type; driver->drv.owner = owner; 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; if (entry->size < sizeof(*entry)) { dev_warn(dev, "coreboot table entry too small!\n"); return -EINVAL; } device = kzalloc(sizeof(device->dev) + entry->size, GFP_KERNEL); if (!device) return -ENOMEM; device->dev.parent = dev; device->dev.bus = &coreboot_bus_type; device->dev.release = coreboot_device_release; memcpy(device->raw, ptr_entry, entry->size); switch (device->entry.tag) { case LB_TAG_CBMEM_ENTRY: dev_set_name(&device->dev, "cbmem-%08x", device->cbmem_entry.id); break; default: dev_set_name(&device->dev, "coreboot%d", i); break; } 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 = coreboot_table_populate(dev, ptr); memunmap(ptr); return ret; } static int __cb_dev_unregister(struct device *dev, void *dummy) { device_unregister(dev); return 0; } static void coreboot_table_remove(struct platform_device *pdev) { bus_for_each_dev(&coreboot_bus_type, NULL, NULL, __cb_dev_unregister); } #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_new = 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), }, }; static int __init coreboot_table_driver_init(void) { int ret; ret = bus_register(&coreboot_bus_type); if (ret) return ret; ret = platform_driver_register(&coreboot_table_driver); if (ret) { bus_unregister(&coreboot_bus_type); return ret; } return 0; } static void __exit coreboot_table_driver_exit(void) { platform_driver_unregister(&coreboot_table_driver); bus_unregister(&coreboot_bus_type); } module_init(coreboot_table_driver_init); module_exit(coreboot_table_driver_exit); MODULE_AUTHOR("Google, Inc."); MODULE_LICENSE("GPL");