blob: 3b8e57969f2a0a6b1bd0ee9ca77c972709478d9f [file] [log] [blame]
/* Copyright 2010, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* This is ported from the flashmap utility: http://flashmap.googlecode.com
*/
#include <stdlib.h>
#include <string.h>
#include "flash.h"
#include "fmap.h"
extern int fmap_find(struct flashchip *flash, uint8_t **buf)
{
unsigned long int offset = 0;
uint64_t sig, tmp64;
struct fmap fmap;
int fmap_size, fmap_found = 0, stride;
memcpy(&sig, FMAP_SIGNATURE, strlen(FMAP_SIGNATURE));
/*
* For efficient operation, we start with the largest stride possible
* and then decrease the stride on each iteration. We will check for a
* remainder when modding the offset with the previous stride. This
* makes it so that each offset is only checked once.
*
* At some point, programmer transaction overhead becomes greater than
* simply copying everything into RAM and checking one byte at a time.
* At some arbitrary point, we'll stop being clever and use brute
* force instead by copying the while ROM into RAM and searching one
* byte at a time.
*
* In practice, the flash map is usually stored in a write-protected
* section of flash which is often at the top of ROM where the boot
* vector on x86 resides. Because of this, we will search from top
* to bottom.
*/
for (stride = (flash->total_size * 1024) / 2; stride >= 16; stride /= 2) {
for (offset = flash->total_size * 1024 - stride;
offset > 0;
offset -= stride) {
if (offset % (stride * 2) == 0)
continue;
if (flash->read(flash, (uint8_t *)&tmp64,
offset, sizeof(tmp64))) {
msg_gdbg("failed to read flash at "
"offset 0x%lx\n", offset);
return -1;
}
if (!memcmp(&tmp64, &sig, sizeof(sig))) {
fmap_found = 1;
break;
}
}
if (fmap_found)
break;
}
/* brute force */
/* FIXME: This results in the entire ROM being read twice -- once here
* and again in doit(). The performance penalty needs to be dealt
* with before going upstream.
*/
if (!fmap_found) {
uint8_t *image = malloc(flash->total_size * 1024);
msg_gdbg("using brute force method to find fmap\n");
flash->read(flash, image, 0, flash->total_size * 1024);
for (offset = flash->total_size * 1024 - sizeof(sig);
offset > 0;
offset--) {
if (!memcmp(&image[offset], &sig, sizeof(sig))) {
fmap_found = 1;
break;
}
}
free(image);
}
if (!fmap_found)
return 0;
if (flash->read(flash, (uint8_t *)&fmap, offset, sizeof(fmap))) {
msg_gdbg("failed to read flash at offset 0x%lx\n", offset);
return -1;
}
fmap_size = sizeof(fmap) + (fmap.nareas * sizeof(struct fmap_area));
*buf = malloc(fmap_size);
if (flash->read(flash, *buf, offset, fmap_size)) {
msg_gdbg("failed to read %d bytes at offset 0x%lx\n",
fmap_size, offset);
return -1;
}
return fmap_size;
}