/* * coreboot_table.c * * Module providing coreboot table access. * * Copyright 2017 Google Inc. * * 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/err.h>#include <linux/init.h>#include <linux/io.h>#include <linux/kernel.h>#include <linux/module.h> #include "coreboot_table.h" struct coreboot_table_entry {	u32 tag;	u32 size;}; static struct coreboot_table_header __iomem *ptr_header; /* * 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(void __iomem *ptr){	ptr_header = ptr; 	return 0;}EXPORT_SYMBOL(coreboot_table_init); int coreboot_table_exit(void){	if (ptr_header)		iounmap(ptr_header); 	return 0;}EXPORT_SYMBOL(coreboot_table_exit); MODULE_AUTHOR("Google, Inc.");MODULE_LICENSE("GPL");