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/*
* coreboot_table.c
*
* Module providing coreboot table access.
*
* Copyright 2017 Google Inc.
* Copyright 2017 Samuel Holland <samuel@sholland.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License v2.0 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#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/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 struct coreboot_table_header __iomem *ptr_header;
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 int __init coreboot_bus_init(void)
{
return bus_register(&coreboot_bus_type);
}
module_init(coreboot_bus_init);
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);
/*
* This function parses the coreboot table for an entry that contains the base
* address of the given entry tag. The coreboot table consists of a header
* directly followed by a number of small, variable-sized entries, which each
* contain an identifying tag and their length as the first two fields.
*/
int coreboot_table_find(int tag, void *data, size_t data_size)
{
struct coreboot_table_header header;
struct coreboot_table_entry entry;
void *ptr_entry;
int i;
if (!ptr_header)
return -EPROBE_DEFER;
memcpy_fromio(&header, ptr_header, sizeof(header));
if (strncmp(header.signature, "LBIO", sizeof(header.signature))) {
pr_warn("coreboot_table: coreboot table missing or corrupt!\n");
return -ENODEV;
}
ptr_entry = (void *)ptr_header + header.header_bytes;
for (i = 0; i < header.table_entries; i++) {
memcpy_fromio(&entry, ptr_entry, sizeof(entry));
if (entry.tag == tag) {
if (data_size < entry.size)
return -EINVAL;
memcpy_fromio(data, ptr_entry, entry.size);
return 0;
}
ptr_entry += entry.size;
}
return -ENOENT;
}
EXPORT_SYMBOL(coreboot_table_find);
int coreboot_table_init(struct device *dev, void __iomem *ptr)
{
int i, ret;
void *ptr_entry;
struct coreboot_device *device;
struct coreboot_table_entry entry;
struct coreboot_table_header header;
ptr_header = ptr;
memcpy_fromio(&header, ptr_header, sizeof(header));
if (strncmp(header.signature, "LBIO", sizeof(header.signature))) {
pr_warn("coreboot_table: coreboot table missing or corrupt!\n");
return -ENODEV;
}
ptr_entry = (void *)ptr_header + header.header_bytes;
for (i = 0; i < header.table_entries; i++) {
memcpy_fromio(&entry, ptr_entry, sizeof(entry));
device = kzalloc(sizeof(struct device) + entry.size, GFP_KERNEL);
if (!device) {
ret = -ENOMEM;
break;
}
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_fromio(&device->entry, ptr_entry, entry.size);
ret = device_register(&device->dev);
if (ret) {
put_device(&device->dev);
break;
}
ptr_entry += entry.size;
}
return ret;
}
EXPORT_SYMBOL(coreboot_table_init);
int coreboot_table_exit(void)
{
if (ptr_header) {
bus_unregister(&coreboot_bus_type);
iounmap(ptr_header);
ptr_header = NULL;
}
return 0;
}
EXPORT_SYMBOL(coreboot_table_exit);
MODULE_AUTHOR("Google, Inc.");
MODULE_LICENSE("GPL");
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