diff options
Diffstat (limited to 'drivers/mtd/bcm47xxpart.c')
| -rw-r--r-- | drivers/mtd/bcm47xxpart.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c new file mode 100644 index 0000000..e06d782 --- /dev/null +++ b/drivers/mtd/bcm47xxpart.c @@ -0,0 +1,202 @@ +/* + * 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 <asm/mach-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"); |