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Some devices (like WNDR3700v3) have board_data without MPFR magic, some extra header or extra NVRAM around 0x100. In such case we have to look for another magic which is BD 0B 0D BD (BD probably stands for Board Data). It's located "far far away", so instead of extending buffer add another mtd_read. Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
278 lines
7.0 KiB
C
278 lines
7.0 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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#include <bcm47xx_nvram.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 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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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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/* 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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