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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 = 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");
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