mirror of https://gitee.com/openkylin/linux.git
95 lines
2.2 KiB
C
95 lines
2.2 KiB
C
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/*
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* coreboot_table.c
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*
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* Module providing coreboot table access.
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*
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* Copyright 2017 Google Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License v2.0 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include "coreboot_table.h"
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struct coreboot_table_entry {
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u32 tag;
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u32 size;
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};
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static struct coreboot_table_header __iomem *ptr_header;
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/*
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* This function parses the coreboot table for an entry that contains the base
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* address of the given entry tag. The coreboot table consists of a header
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* directly followed by a number of small, variable-sized entries, which each
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* contain an identifying tag and their length as the first two fields.
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*/
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int coreboot_table_find(int tag, void *data, size_t data_size)
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{
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struct coreboot_table_header header;
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struct coreboot_table_entry entry;
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void *ptr_entry;
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int i;
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if (!ptr_header)
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return -EPROBE_DEFER;
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memcpy_fromio(&header, ptr_header, sizeof(header));
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if (strncmp(header.signature, "LBIO", sizeof(header.signature))) {
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pr_warn("coreboot_table: coreboot table missing or corrupt!\n");
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return -ENODEV;
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}
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ptr_entry = (void *)ptr_header + header.header_bytes;
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for (i = 0; i < header.table_entries; i++) {
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memcpy_fromio(&entry, ptr_entry, sizeof(entry));
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if (entry.tag == tag) {
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if (data_size < entry.size)
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return -EINVAL;
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memcpy_fromio(data, ptr_entry, entry.size);
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return 0;
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}
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ptr_entry += entry.size;
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}
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return -ENOENT;
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}
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EXPORT_SYMBOL(coreboot_table_find);
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int coreboot_table_init(void __iomem *ptr)
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{
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ptr_header = ptr;
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return 0;
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}
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EXPORT_SYMBOL(coreboot_table_init);
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int coreboot_table_exit(void)
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{
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if (ptr_header)
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iounmap(ptr_header);
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return 0;
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}
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EXPORT_SYMBOL(coreboot_table_exit);
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MODULE_AUTHOR("Google, Inc.");
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MODULE_LICENSE("GPL");
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