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/*
* BCM47XX MTD partitioning
*
* Copyright © 2012 Rafał Miłecki <zajec5@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <bcm47xx_nvram.h>
/* 10 parts were found on sflash on Netgear WNDR4500 */
#define BCM47XXPART_MAX_PARTS 12
/*
* Amount of bytes we read when analyzing each block of flash memory.
* Set it big enough to allow detecting partition and reading important data.
*/
#define BCM47XXPART_BYTES_TO_READ 0x404
/* Magics */
#define BOARD_DATA_MAGIC 0x5246504D /* MPFR */
#define POT_MAGIC1 0x54544f50 /* POTT */
#define POT_MAGIC2 0x504f /* OP */
#define ML_MAGIC1 0x39685a42
#define ML_MAGIC2 0x26594131
#define TRX_MAGIC 0x30524448
struct trx_header {
uint32_t magic;
uint32_t length;
uint32_t crc32;
uint16_t flags;
uint16_t version;
uint32_t offset[3];
} __packed;
static void bcm47xxpart_add_part(struct mtd_partition *part, char *name,
u64 offset, uint32_t mask_flags)
{
part->name = name;
part->offset = offset;
part->mask_flags = mask_flags;
}
static int bcm47xxpart_parse(struct mtd_info *master,
struct mtd_partition **pparts,
struct mtd_part_parser_data *data)
{
struct mtd_partition *parts;
uint8_t i, curr_part = 0;
uint32_t *buf;
size_t bytes_read;
uint32_t offset;
uint32_t blocksize = 0x10000;
struct trx_header *trx;
/* Alloc */
parts = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
GFP_KERNEL);
buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);
/* Parse block by block looking for magics */
for (offset = 0; offset <= master->size - blocksize;
offset += blocksize) {
/* Nothing more in higher memory */
if (offset >= 0x2000000)
break;
if (curr_part > BCM47XXPART_MAX_PARTS) {
pr_warn("Reached maximum number of partitions, scanning stopped!\n");
break;
}
/* Read beginning of the block */
if (mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
&bytes_read, (uint8_t *)buf) < 0) {
pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
offset);
continue;
}
/* CFE has small NVRAM at 0x400 */
if (buf[0x400 / 4] == NVRAM_HEADER) {
bcm47xxpart_add_part(&parts[curr_part++], "boot",
offset, MTD_WRITEABLE);
continue;
}
/* Standard NVRAM */
if (buf[0x000 / 4] == NVRAM_HEADER) {
bcm47xxpart_add_part(&parts[curr_part++], "nvram",
offset, 0);
continue;
}
/*
* board_data starts with board_id which differs across boards,
* but we can use 'MPFR' (hopefully) magic at 0x100
*/
if (buf[0x100 / 4] == BOARD_DATA_MAGIC) {
bcm47xxpart_add_part(&parts[curr_part++], "board_data",
offset, MTD_WRITEABLE);
continue;
}
/* POT(TOP) */
if (buf[0x000 / 4] == POT_MAGIC1 &&
(buf[0x004 / 4] & 0xFFFF) == POT_MAGIC2) {
bcm47xxpart_add_part(&parts[curr_part++], "POT", offset,
MTD_WRITEABLE);
continue;
}
/* ML */
if (buf[0x010 / 4] == ML_MAGIC1 &&
buf[0x014 / 4] == ML_MAGIC2) {
bcm47xxpart_add_part(&parts[curr_part++], "ML", offset,
MTD_WRITEABLE);
continue;
}
/* TRX */
if (buf[0x000 / 4] == TRX_MAGIC) {
trx = (struct trx_header *)buf;
i = 0;
/* We have LZMA loader if offset[2] points to sth */
if (trx->offset[2]) {
bcm47xxpart_add_part(&parts[curr_part++],
"loader",
offset + trx->offset[i],
0);
i++;
}
bcm47xxpart_add_part(&parts[curr_part++], "linux",
offset + trx->offset[i], 0);
i++;
/*
* Pure rootfs size is known and can be calculated as:
* trx->length - trx->offset[i]. We don't fill it as
* we want to have jffs2 (overlay) in the same mtd.
*/
bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
offset + trx->offset[i], 0);
i++;
/*
* We have whole TRX scanned, skip to the next part. Use
* roundown (not roundup), as the loop will increase
* offset in next step.
*/
offset = rounddown(offset + trx->length, blocksize);
continue;
}
}
kfree(buf);
/*
* Assume that partitions end at the beginning of the one they are
* followed by.
*/
for (i = 0; i < curr_part - 1; i++)
parts[i].size = parts[i + 1].offset - parts[i].offset;
if (curr_part > 0)
parts[curr_part - 1].size =
master->size - parts[curr_part - 1].offset;
*pparts = parts;
return curr_part;
};
static struct mtd_part_parser bcm47xxpart_mtd_parser = {
.owner = THIS_MODULE,
.parse_fn = bcm47xxpart_parse,
.name = "bcm47xxpart",
};
static int __init bcm47xxpart_init(void)
{
return register_mtd_parser(&bcm47xxpart_mtd_parser);
}
static void __exit bcm47xxpart_exit(void)
{
deregister_mtd_parser(&bcm47xxpart_mtd_parser);
}
module_init(bcm47xxpart_init);
module_exit(bcm47xxpart_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories");
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