1/*
2 * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
3 * Use of this source code is governed by a BSD-style license that can be
4 * found in the LICENSE file.
5 */
6
7#include <stdio.h>
8#include <string.h>
9
10#include "fmap.h"
11
12static int is_fmap(uint8_t *ptr)
13{
14	FmapHeader *fmap_header = (FmapHeader *)ptr;
15
16	if (0 != memcmp(ptr, FMAP_SIGNATURE, FMAP_SIGNATURE_SIZE))
17		return 0;
18
19	if (fmap_header->fmap_ver_major == FMAP_VER_MAJOR)
20		return 1;
21
22	fprintf(stderr, "Found FMAP, but major version is %u instead of %u\n",
23		fmap_header->fmap_ver_major, FMAP_VER_MAJOR);
24	return 0;
25}
26
27/* Find and point to the FMAP header within the buffer */
28FmapHeader *fmap_find(uint8_t *ptr, size_t size)
29{
30	ssize_t offset, align;
31	ssize_t lim = size - sizeof(FmapHeader);
32
33	if (lim >= 0 && is_fmap(ptr))
34		return (FmapHeader *)ptr;
35
36	/* Search large alignments before small ones to find "right" FMAP. */
37	for (align = FMAP_SEARCH_STRIDE; align <= lim; align *= 2);
38	for (; align >= FMAP_SEARCH_STRIDE; align /= 2)
39		for (offset = align; offset <= lim; offset += align * 2)
40			if (is_fmap(ptr + offset))
41				return (FmapHeader *)(ptr + offset);
42
43	return NULL;
44}
45
46/* Search for an area by name, return pointer to its beginning */
47uint8_t *fmap_find_by_name(uint8_t *ptr, size_t size, FmapHeader *fmap,
48			   const char *name, FmapAreaHeader **ah_ptr)
49{
50	int i;
51	FmapAreaHeader *ah;
52
53	if (!fmap)
54		fmap = fmap_find(ptr, size);
55	if (!fmap)
56		return NULL;
57
58	ah = (FmapAreaHeader*)((void *)fmap + sizeof(FmapHeader));
59	for (i = 0; i < fmap->fmap_nareas; i++)
60		if (!strncmp(ah[i].area_name, name, FMAP_NAMELEN)) {
61			if (ah_ptr)
62				*ah_ptr = ah + i;
63			return ptr + ah[i].area_offset;
64		}
65
66	return NULL;
67}
68