99352afe8f
This makes TRX parsing code reusable with other platforms and parsers. Please note this patch doesn't really change anything in the existing code, just moves it. There is still some place for improvement (e.g. working on non-hacky method of checking rootfs format) but it's not really a subject of this change. Signed-off-by: Rafał Miłecki <rafal@milecki.pl> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
301 lines
8.1 KiB
C
301 lines
8.1 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/bcm47xx_nvram.h>
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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 <uapi/linux/magic.h>
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/*
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* NAND flash on Netgear R6250 was verified to contain 15 partitions.
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* This will result in allocating too big array for some old devices, but the
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* memory will be freed soon anyway (see mtd_device_parse_register).
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*/
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#define BCM47XXPART_MAX_PARTS 20
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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 SHSQ_MAGIC 0x71736873 /* shsq (weird ZTE H218N endianness) */
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static const char * const trx_types[] = { "trx", NULL };
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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, const 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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/**
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* bcm47xxpart_bootpartition - gets index of TRX partition used by bootloader
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*
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* Some devices may have more than one TRX partition. In such case one of them
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* is the main one and another a failsafe one. Bootloader may fallback to the
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* failsafe firmware if it detects corruption of the main image.
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*
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* This function provides info about currently used TRX partition. It's the one
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* containing kernel started by the bootloader.
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*/
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static int bcm47xxpart_bootpartition(void)
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{
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char buf[4];
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int bootpartition;
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/* Check CFE environment variable */
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if (bcm47xx_nvram_getenv("bootpartition", buf, sizeof(buf)) > 0) {
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if (!kstrtoint(buf, 0, &bootpartition))
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return bootpartition;
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}
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return 0;
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}
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static int bcm47xxpart_parse(struct mtd_info *master,
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const 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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int trx_parts[2]; /* Array with indexes of TRX partitions */
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int trx_num = 0; /* Number of found TRX partitions */
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int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
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int err;
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/*
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* Some really old flashes (like AT45DB*) had smaller erasesize-s, but
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* partitions were aligned to at least 0x1000 anyway.
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*/
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if (blocksize < 0x1000)
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blocksize = 0x1000;
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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 on BCM47XX (MIPS) */
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if (IS_ENABLED(CONFIG_BCM47XX) && 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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err = mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
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&bytes_read, (uint8_t *)buf);
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if (err && !mtd_is_bitflip(err)) {
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pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
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offset, err);
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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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struct trx_header *trx;
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if (trx_num >= ARRAY_SIZE(trx_parts))
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pr_warn("No enough space to store another TRX found at 0x%X\n",
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offset);
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else
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trx_parts[trx_num++] = curr_part;
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bcm47xxpart_add_part(&parts[curr_part++], "firmware",
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offset, 0);
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/* Jump to the end of TRX */
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trx = (struct trx_header *)buf;
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offset = roundup(offset + trx->length, blocksize);
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/* Next loop iteration will increase the offset */
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offset -= 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 (le32_to_cpu(buf[0x000 / 4]) == SQUASHFS_MAGIC ||
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buf[0x000 / 4] == SHSQ_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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err = mtd_read(master, offset + 0x8000, 0x4, &bytes_read,
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(uint8_t *)buf);
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if (err && !mtd_is_bitflip(err)) {
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pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
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offset, err);
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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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err = mtd_read(master, offset, 0x4, &bytes_read,
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(uint8_t *)buf);
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if (err && !mtd_is_bitflip(err)) {
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pr_err("mtd_read error while reading (offset 0x%X): %d\n",
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offset, err);
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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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}
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/* If there was TRX parse it now */
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for (i = 0; i < trx_num; i++) {
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struct mtd_partition *trx = &parts[trx_parts[i]];
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if (i == bcm47xxpart_bootpartition())
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trx->types = trx_types;
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else
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trx->name = "failsafe";
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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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.parse_fn = bcm47xxpart_parse,
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.name = "bcm47xxpart",
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};
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module_mtd_part_parser(bcm47xxpart_mtd_parser);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories");
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