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024629fdca
Old devices used to have NVRAM at the very end of flash and they could be unaligned (starting at some offset in a block). In new devices NVRAM can be located quite randomly, however it seems to always start at the beginning of a block. For example Netgear R6250 has NVRAM located right after the bootloader, before the kernel partition. Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
294 lines
7.4 KiB
C
294 lines
7.4 KiB
C
/*
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* BCM47XX MTD partitioning
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*
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* Copyright © 2012 Rafał Miłecki <zajec5@gmail.com>
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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 version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/partitions.h>
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/* 10 parts were found on sflash on Netgear WNDR4500 */
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#define BCM47XXPART_MAX_PARTS 12
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/*
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* Amount of bytes we read when analyzing each block of flash memory.
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* Set it big enough to allow detecting partition and reading important data.
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*/
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#define BCM47XXPART_BYTES_TO_READ 0x4e8
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/* Magics */
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#define BOARD_DATA_MAGIC 0x5246504D /* MPFR */
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#define BOARD_DATA_MAGIC2 0xBD0D0BBD
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#define CFE_MAGIC 0x43464531 /* 1EFC */
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#define FACTORY_MAGIC 0x59544346 /* FCTY */
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#define NVRAM_HEADER 0x48534C46 /* FLSH */
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#define POT_MAGIC1 0x54544f50 /* POTT */
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#define POT_MAGIC2 0x504f /* OP */
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#define ML_MAGIC1 0x39685a42
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#define ML_MAGIC2 0x26594131
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#define TRX_MAGIC 0x30524448
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#define SQSH_MAGIC 0x71736873 /* shsq */
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struct trx_header {
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uint32_t magic;
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uint32_t length;
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uint32_t crc32;
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uint16_t flags;
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uint16_t version;
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uint32_t offset[3];
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} __packed;
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static void bcm47xxpart_add_part(struct mtd_partition *part, char *name,
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u64 offset, uint32_t mask_flags)
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{
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part->name = name;
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part->offset = offset;
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part->mask_flags = mask_flags;
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}
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static int bcm47xxpart_parse(struct mtd_info *master,
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struct mtd_partition **pparts,
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struct mtd_part_parser_data *data)
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{
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struct mtd_partition *parts;
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uint8_t i, curr_part = 0;
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uint32_t *buf;
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size_t bytes_read;
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uint32_t offset;
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uint32_t blocksize = master->erasesize;
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struct trx_header *trx;
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int trx_part = -1;
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int last_trx_part = -1;
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int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
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if (blocksize <= 0x10000)
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blocksize = 0x10000;
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/* Alloc */
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parts = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
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GFP_KERNEL);
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if (!parts)
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return -ENOMEM;
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buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);
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if (!buf) {
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kfree(parts);
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return -ENOMEM;
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}
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/* Parse block by block looking for magics */
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for (offset = 0; offset <= master->size - blocksize;
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offset += blocksize) {
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/* Nothing more in higher memory */
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if (offset >= 0x2000000)
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break;
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if (curr_part >= BCM47XXPART_MAX_PARTS) {
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pr_warn("Reached maximum number of partitions, scanning stopped!\n");
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break;
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}
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/* Read beginning of the block */
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if (mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
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&bytes_read, (uint8_t *)buf) < 0) {
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pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
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offset);
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continue;
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}
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/* Magic or small NVRAM at 0x400 */
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if ((buf[0x4e0 / 4] == CFE_MAGIC && buf[0x4e4 / 4] == CFE_MAGIC) ||
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(buf[0x400 / 4] == NVRAM_HEADER)) {
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bcm47xxpart_add_part(&parts[curr_part++], "boot",
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offset, MTD_WRITEABLE);
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continue;
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}
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/*
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* board_data starts with board_id which differs across boards,
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* but we can use 'MPFR' (hopefully) magic at 0x100
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*/
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if (buf[0x100 / 4] == BOARD_DATA_MAGIC) {
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bcm47xxpart_add_part(&parts[curr_part++], "board_data",
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offset, MTD_WRITEABLE);
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continue;
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}
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/* Found on Huawei E970 */
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if (buf[0x000 / 4] == FACTORY_MAGIC) {
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bcm47xxpart_add_part(&parts[curr_part++], "factory",
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offset, MTD_WRITEABLE);
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continue;
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}
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/* POT(TOP) */
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if (buf[0x000 / 4] == POT_MAGIC1 &&
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(buf[0x004 / 4] & 0xFFFF) == POT_MAGIC2) {
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bcm47xxpart_add_part(&parts[curr_part++], "POT", offset,
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MTD_WRITEABLE);
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continue;
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}
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/* ML */
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if (buf[0x010 / 4] == ML_MAGIC1 &&
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buf[0x014 / 4] == ML_MAGIC2) {
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bcm47xxpart_add_part(&parts[curr_part++], "ML", offset,
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MTD_WRITEABLE);
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continue;
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}
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/* TRX */
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if (buf[0x000 / 4] == TRX_MAGIC) {
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if (BCM47XXPART_MAX_PARTS - curr_part < 4) {
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pr_warn("Not enough partitions left to register trx, scanning stopped!\n");
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break;
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}
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trx = (struct trx_header *)buf;
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trx_part = curr_part;
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bcm47xxpart_add_part(&parts[curr_part++], "firmware",
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offset, 0);
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i = 0;
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/* We have LZMA loader if offset[2] points to sth */
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if (trx->offset[2]) {
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bcm47xxpart_add_part(&parts[curr_part++],
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"loader",
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offset + trx->offset[i],
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0);
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i++;
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}
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bcm47xxpart_add_part(&parts[curr_part++], "linux",
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offset + trx->offset[i], 0);
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i++;
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/*
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* Pure rootfs size is known and can be calculated as:
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* trx->length - trx->offset[i]. We don't fill it as
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* we want to have jffs2 (overlay) in the same mtd.
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*/
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bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
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offset + trx->offset[i], 0);
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i++;
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last_trx_part = curr_part - 1;
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/*
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* We have whole TRX scanned, skip to the next part. Use
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* roundown (not roundup), as the loop will increase
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* offset in next step.
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*/
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offset = rounddown(offset + trx->length, blocksize);
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continue;
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}
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/* Squashfs on devices not using TRX */
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if (buf[0x000 / 4] == SQSH_MAGIC) {
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bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
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offset, 0);
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continue;
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}
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/*
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* New (ARM?) devices may have NVRAM in some middle block. Last
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* block will be checked later, so skip it.
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*/
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if (offset != master->size - blocksize &&
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buf[0x000 / 4] == NVRAM_HEADER) {
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bcm47xxpart_add_part(&parts[curr_part++], "nvram",
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offset, 0);
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continue;
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}
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/* Read middle of the block */
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if (mtd_read(master, offset + 0x8000, 0x4,
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&bytes_read, (uint8_t *)buf) < 0) {
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pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
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offset);
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continue;
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}
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/* Some devices (ex. WNDR3700v3) don't have a standard 'MPFR' */
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if (buf[0x000 / 4] == BOARD_DATA_MAGIC2) {
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bcm47xxpart_add_part(&parts[curr_part++], "board_data",
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offset, MTD_WRITEABLE);
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continue;
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}
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}
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/* Look for NVRAM at the end of the last block. */
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for (i = 0; i < ARRAY_SIZE(possible_nvram_sizes); i++) {
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if (curr_part >= BCM47XXPART_MAX_PARTS) {
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pr_warn("Reached maximum number of partitions, scanning stopped!\n");
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break;
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}
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offset = master->size - possible_nvram_sizes[i];
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if (mtd_read(master, offset, 0x4, &bytes_read,
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(uint8_t *)buf) < 0) {
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pr_err("mtd_read error while reading at offset 0x%X!\n",
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offset);
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continue;
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}
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/* Standard NVRAM */
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if (buf[0] == NVRAM_HEADER) {
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bcm47xxpart_add_part(&parts[curr_part++], "nvram",
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master->size - blocksize, 0);
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break;
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}
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}
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kfree(buf);
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/*
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* Assume that partitions end at the beginning of the one they are
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* followed by.
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*/
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for (i = 0; i < curr_part; i++) {
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u64 next_part_offset = (i < curr_part - 1) ?
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parts[i + 1].offset : master->size;
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parts[i].size = next_part_offset - parts[i].offset;
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if (i == last_trx_part && trx_part >= 0)
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parts[trx_part].size = next_part_offset -
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parts[trx_part].offset;
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}
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*pparts = parts;
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return curr_part;
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};
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static struct mtd_part_parser bcm47xxpart_mtd_parser = {
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.owner = THIS_MODULE,
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.parse_fn = bcm47xxpart_parse,
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.name = "bcm47xxpart",
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};
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static int __init bcm47xxpart_init(void)
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{
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register_mtd_parser(&bcm47xxpart_mtd_parser);
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return 0;
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}
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static void __exit bcm47xxpart_exit(void)
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{
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deregister_mtd_parser(&bcm47xxpart_mtd_parser);
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}
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module_init(bcm47xxpart_init);
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module_exit(bcm47xxpart_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories");
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