diff options
Diffstat (limited to 'drivers/firmware/google/coreboot_table.c')
| -rw-r--r-- | drivers/firmware/google/coreboot_table.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c new file mode 100644 index 000000000..33ae94745 --- /dev/null +++ b/drivers/firmware/google/coreboot_table.c @@ -0,0 +1,239 @@ +// 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 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 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; + + 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 int coreboot_table_remove(struct platform_device *pdev) +{ + bus_for_each_dev(&coreboot_bus_type, NULL, NULL, __cb_dev_unregister); + 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), + }, +}; + +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"); |