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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * BCM47XX MTD partitioning4 *5 * Copyright © 2012 Rafał Miłecki <zajec5@gmail.com>6 */7 8#include <linux/bcm47xx_nvram.h>9#include <linux/module.h>10#include <linux/kernel.h>11#include <linux/slab.h>12#include <linux/mtd/mtd.h>13#include <linux/mtd/partitions.h>14 15#include <uapi/linux/magic.h>16 17/*18 * NAND flash on Netgear R6250 was verified to contain 15 partitions.19 * This will result in allocating too big array for some old devices, but the20 * memory will be freed soon anyway (see mtd_device_parse_register).21 */22#define BCM47XXPART_MAX_PARTS 2023 24/*25 * Amount of bytes we read when analyzing each block of flash memory.26 * Set it big enough to allow detecting partition and reading important data.27 */28#define BCM47XXPART_BYTES_TO_READ 0x4e829 30/* Magics */31#define BOARD_DATA_MAGIC 0x5246504D /* MPFR */32#define BOARD_DATA_MAGIC2 0xBD0D0BBD33#define CFE_MAGIC 0x43464531 /* 1EFC */34#define FACTORY_MAGIC 0x59544346 /* FCTY */35#define NVRAM_HEADER 0x48534C46 /* FLSH */36#define POT_MAGIC1 0x54544f50 /* POTT */37#define POT_MAGIC2 0x504f /* OP */38#define ML_MAGIC1 0x39685a4239#define ML_MAGIC2 0x2659413140#define TRX_MAGIC 0x3052444841#define SHSQ_MAGIC 0x71736873 /* shsq (weird ZTE H218N endianness) */42 43static const char * const trx_types[] = { "trx", NULL };44 45struct trx_header {46 uint32_t magic;47 uint32_t length;48 uint32_t crc32;49 uint16_t flags;50 uint16_t version;51 uint32_t offset[3];52} __packed;53 54static void bcm47xxpart_add_part(struct mtd_partition *part, const char *name,55 u64 offset, uint32_t mask_flags)56{57 part->name = name;58 part->offset = offset;59 part->mask_flags = mask_flags;60}61 62/**63 * bcm47xxpart_bootpartition - gets index of TRX partition used by bootloader64 *65 * Some devices may have more than one TRX partition. In such case one of them66 * is the main one and another a failsafe one. Bootloader may fallback to the67 * failsafe firmware if it detects corruption of the main image.68 *69 * This function provides info about currently used TRX partition. It's the one70 * containing kernel started by the bootloader.71 */72static int bcm47xxpart_bootpartition(void)73{74 char buf[4];75 int bootpartition;76 77 /* Check CFE environment variable */78 if (bcm47xx_nvram_getenv("bootpartition", buf, sizeof(buf)) > 0) {79 if (!kstrtoint(buf, 0, &bootpartition))80 return bootpartition;81 }82 83 return 0;84}85 86static int bcm47xxpart_parse(struct mtd_info *master,87 const struct mtd_partition **pparts,88 struct mtd_part_parser_data *data)89{90 struct mtd_partition *parts;91 uint8_t i, curr_part = 0;92 uint32_t *buf;93 size_t bytes_read;94 uint32_t offset;95 uint32_t blocksize = master->erasesize;96 int trx_parts[2]; /* Array with indexes of TRX partitions */97 int trx_num = 0; /* Number of found TRX partitions */98 static const int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };99 int err;100 101 /*102 * Some really old flashes (like AT45DB*) had smaller erasesize-s, but103 * partitions were aligned to at least 0x1000 anyway.104 */105 if (blocksize < 0x1000)106 blocksize = 0x1000;107 108 /* Alloc */109 parts = kcalloc(BCM47XXPART_MAX_PARTS, sizeof(struct mtd_partition),110 GFP_KERNEL);111 if (!parts)112 return -ENOMEM;113 114 buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);115 if (!buf) {116 kfree(parts);117 return -ENOMEM;118 }119 120 /* Parse block by block looking for magics */121 for (offset = 0; offset <= master->size - blocksize;122 offset += blocksize) {123 /* Nothing more in higher memory on BCM47XX (MIPS) */124 if (IS_ENABLED(CONFIG_BCM47XX) && offset >= 0x2000000)125 break;126 127 if (curr_part >= BCM47XXPART_MAX_PARTS) {128 pr_warn("Reached maximum number of partitions, scanning stopped!\n");129 break;130 }131 132 /* Read beginning of the block */133 err = mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,134 &bytes_read, (uint8_t *)buf);135 if (err && !mtd_is_bitflip(err)) {136 pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",137 offset, err);138 continue;139 }140 141 /* Magic or small NVRAM at 0x400 */142 if ((buf[0x4e0 / 4] == CFE_MAGIC && buf[0x4e4 / 4] == CFE_MAGIC) ||143 (buf[0x400 / 4] == NVRAM_HEADER)) {144 bcm47xxpart_add_part(&parts[curr_part++], "boot",145 offset, MTD_WRITEABLE);146 continue;147 }148 149 /*150 * board_data starts with board_id which differs across boards,151 * but we can use 'MPFR' (hopefully) magic at 0x100152 */153 if (buf[0x100 / 4] == BOARD_DATA_MAGIC) {154 bcm47xxpart_add_part(&parts[curr_part++], "board_data",155 offset, MTD_WRITEABLE);156 continue;157 }158 159 /* Found on Huawei E970 */160 if (buf[0x000 / 4] == FACTORY_MAGIC) {161 bcm47xxpart_add_part(&parts[curr_part++], "factory",162 offset, MTD_WRITEABLE);163 continue;164 }165 166 /* POT(TOP) */167 if (buf[0x000 / 4] == POT_MAGIC1 &&168 (buf[0x004 / 4] & 0xFFFF) == POT_MAGIC2) {169 bcm47xxpart_add_part(&parts[curr_part++], "POT", offset,170 MTD_WRITEABLE);171 continue;172 }173 174 /* ML */175 if (buf[0x010 / 4] == ML_MAGIC1 &&176 buf[0x014 / 4] == ML_MAGIC2) {177 bcm47xxpart_add_part(&parts[curr_part++], "ML", offset,178 MTD_WRITEABLE);179 continue;180 }181 182 /* TRX */183 if (buf[0x000 / 4] == TRX_MAGIC) {184 struct trx_header *trx;185 uint32_t last_subpart;186 uint32_t trx_size;187 188 if (trx_num >= ARRAY_SIZE(trx_parts))189 pr_warn("No enough space to store another TRX found at 0x%X\n",190 offset);191 else192 trx_parts[trx_num++] = curr_part;193 bcm47xxpart_add_part(&parts[curr_part++], "firmware",194 offset, 0);195 196 /*197 * Try to find TRX size. The "length" field isn't fully198 * reliable as it could be decreased to make CRC32 cover199 * only part of TRX data. It's commonly used as checksum200 * can't cover e.g. ever-changing rootfs partition.201 * Use offsets as helpers for assuming min TRX size.202 */203 trx = (struct trx_header *)buf;204 last_subpart = max3(trx->offset[0], trx->offset[1],205 trx->offset[2]);206 trx_size = max(trx->length, last_subpart + blocksize);207 208 /*209 * Skip the TRX data. Decrease offset by block size as210 * the next loop iteration will increase it.211 */212 offset += roundup(trx_size, blocksize) - blocksize;213 continue;214 }215 216 /* Squashfs on devices not using TRX */217 if (le32_to_cpu(buf[0x000 / 4]) == SQUASHFS_MAGIC ||218 buf[0x000 / 4] == SHSQ_MAGIC) {219 bcm47xxpart_add_part(&parts[curr_part++], "rootfs",220 offset, 0);221 continue;222 }223 224 /*225 * New (ARM?) devices may have NVRAM in some middle block. Last226 * block will be checked later, so skip it.227 */228 if (offset != master->size - blocksize &&229 buf[0x000 / 4] == NVRAM_HEADER) {230 bcm47xxpart_add_part(&parts[curr_part++], "nvram",231 offset, 0);232 continue;233 }234 235 /* Read middle of the block */236 err = mtd_read(master, offset + (blocksize / 2), 0x4, &bytes_read,237 (uint8_t *)buf);238 if (err && !mtd_is_bitflip(err)) {239 pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",240 offset + (blocksize / 2), err);241 continue;242 }243 244 /* Some devices (ex. WNDR3700v3) don't have a standard 'MPFR' */245 if (buf[0x000 / 4] == BOARD_DATA_MAGIC2) {246 bcm47xxpart_add_part(&parts[curr_part++], "board_data",247 offset, MTD_WRITEABLE);248 continue;249 }250 }251 252 /* Look for NVRAM at the end of the last block. */253 for (i = 0; i < ARRAY_SIZE(possible_nvram_sizes); i++) {254 if (curr_part >= BCM47XXPART_MAX_PARTS) {255 pr_warn("Reached maximum number of partitions, scanning stopped!\n");256 break;257 }258 259 offset = master->size - possible_nvram_sizes[i];260 err = mtd_read(master, offset, 0x4, &bytes_read,261 (uint8_t *)buf);262 if (err && !mtd_is_bitflip(err)) {263 pr_err("mtd_read error while reading (offset 0x%X): %d\n",264 offset, err);265 continue;266 }267 268 /* Standard NVRAM */269 if (buf[0] == NVRAM_HEADER) {270 bcm47xxpart_add_part(&parts[curr_part++], "nvram",271 master->size - blocksize, 0);272 break;273 }274 }275 276 kfree(buf);277 278 /*279 * Assume that partitions end at the beginning of the one they are280 * followed by.281 */282 for (i = 0; i < curr_part; i++) {283 u64 next_part_offset = (i < curr_part - 1) ?284 parts[i + 1].offset : master->size;285 286 parts[i].size = next_part_offset - parts[i].offset;287 }288 289 /* If there was TRX parse it now */290 for (i = 0; i < trx_num; i++) {291 struct mtd_partition *trx = &parts[trx_parts[i]];292 293 if (i == bcm47xxpart_bootpartition())294 trx->types = trx_types;295 else296 trx->name = "failsafe";297 }298 299 *pparts = parts;300 return curr_part;301};302 303static const struct of_device_id bcm47xxpart_of_match_table[] = {304 { .compatible = "brcm,bcm947xx-cfe-partitions" },305 {},306};307MODULE_DEVICE_TABLE(of, bcm47xxpart_of_match_table);308 309static struct mtd_part_parser bcm47xxpart_mtd_parser = {310 .parse_fn = bcm47xxpart_parse,311 .name = "bcm47xxpart",312 .of_match_table = bcm47xxpart_of_match_table,313};314module_mtd_part_parser(bcm47xxpart_mtd_parser);315 316MODULE_LICENSE("GPL");317MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories");318