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-rw-r--r--drivers/mtd/bcm47xxpart.c321
1 files changed, 321 insertions, 0 deletions
diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c
new file mode 100644
index 000000000..fc424b185
--- /dev/null
+++ b/drivers/mtd/bcm47xxpart.c
@@ -0,0 +1,321 @@
+/*
+ * 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/bcm47xx_nvram.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+
+#include <uapi/linux/magic.h>
+
+/*
+ * NAND flash on Netgear R6250 was verified to contain 15 partitions.
+ * This will result in allocating too big array for some old devices, but the
+ * memory will be freed soon anyway (see mtd_device_parse_register).
+ */
+#define BCM47XXPART_MAX_PARTS 20
+
+/*
+ * 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 0x4e8
+
+/* Magics */
+#define BOARD_DATA_MAGIC 0x5246504D /* MPFR */
+#define BOARD_DATA_MAGIC2 0xBD0D0BBD
+#define CFE_MAGIC 0x43464531 /* 1EFC */
+#define FACTORY_MAGIC 0x59544346 /* FCTY */
+#define NVRAM_HEADER 0x48534C46 /* FLSH */
+#define POT_MAGIC1 0x54544f50 /* POTT */
+#define POT_MAGIC2 0x504f /* OP */
+#define ML_MAGIC1 0x39685a42
+#define ML_MAGIC2 0x26594131
+#define TRX_MAGIC 0x30524448
+#define SHSQ_MAGIC 0x71736873 /* shsq (weird ZTE H218N endianness) */
+
+static const char * const trx_types[] = { "trx", NULL };
+
+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, const char *name,
+ u64 offset, uint32_t mask_flags)
+{
+ part->name = name;
+ part->offset = offset;
+ part->mask_flags = mask_flags;
+}
+
+/**
+ * bcm47xxpart_bootpartition - gets index of TRX partition used by bootloader
+ *
+ * Some devices may have more than one TRX partition. In such case one of them
+ * is the main one and another a failsafe one. Bootloader may fallback to the
+ * failsafe firmware if it detects corruption of the main image.
+ *
+ * This function provides info about currently used TRX partition. It's the one
+ * containing kernel started by the bootloader.
+ */
+static int bcm47xxpart_bootpartition(void)
+{
+ char buf[4];
+ int bootpartition;
+
+ /* Check CFE environment variable */
+ if (bcm47xx_nvram_getenv("bootpartition", buf, sizeof(buf)) > 0) {
+ if (!kstrtoint(buf, 0, &bootpartition))
+ return bootpartition;
+ }
+
+ return 0;
+}
+
+static int bcm47xxpart_parse(struct mtd_info *master,
+ const 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 = master->erasesize;
+ int trx_parts[2]; /* Array with indexes of TRX partitions */
+ int trx_num = 0; /* Number of found TRX partitions */
+ int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
+ int err;
+
+ /*
+ * Some really old flashes (like AT45DB*) had smaller erasesize-s, but
+ * partitions were aligned to at least 0x1000 anyway.
+ */
+ if (blocksize < 0x1000)
+ blocksize = 0x1000;
+
+ /* Alloc */
+ parts = kcalloc(BCM47XXPART_MAX_PARTS, sizeof(struct mtd_partition),
+ GFP_KERNEL);
+ if (!parts)
+ return -ENOMEM;
+
+ buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);
+ if (!buf) {
+ kfree(parts);
+ return -ENOMEM;
+ }
+
+ /* Parse block by block looking for magics */
+ for (offset = 0; offset <= master->size - blocksize;
+ offset += blocksize) {
+ /* Nothing more in higher memory on BCM47XX (MIPS) */
+ if (IS_ENABLED(CONFIG_BCM47XX) && 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 */
+ err = mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
+ &bytes_read, (uint8_t *)buf);
+ if (err && !mtd_is_bitflip(err)) {
+ pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
+ offset, err);
+ continue;
+ }
+
+ /* Magic or small NVRAM at 0x400 */
+ if ((buf[0x4e0 / 4] == CFE_MAGIC && buf[0x4e4 / 4] == CFE_MAGIC) ||
+ (buf[0x400 / 4] == NVRAM_HEADER)) {
+ bcm47xxpart_add_part(&parts[curr_part++], "boot",
+ offset, MTD_WRITEABLE);
+ 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;
+ }
+
+ /* Found on Huawei E970 */
+ if (buf[0x000 / 4] == FACTORY_MAGIC) {
+ bcm47xxpart_add_part(&parts[curr_part++], "factory",
+ 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) {
+ struct trx_header *trx;
+ uint32_t last_subpart;
+ uint32_t trx_size;
+
+ if (trx_num >= ARRAY_SIZE(trx_parts))
+ pr_warn("No enough space to store another TRX found at 0x%X\n",
+ offset);
+ else
+ trx_parts[trx_num++] = curr_part;
+ bcm47xxpart_add_part(&parts[curr_part++], "firmware",
+ offset, 0);
+
+ /*
+ * Try to find TRX size. The "length" field isn't fully
+ * reliable as it could be decreased to make CRC32 cover
+ * only part of TRX data. It's commonly used as checksum
+ * can't cover e.g. ever-changing rootfs partition.
+ * Use offsets as helpers for assuming min TRX size.
+ */
+ trx = (struct trx_header *)buf;
+ last_subpart = max3(trx->offset[0], trx->offset[1],
+ trx->offset[2]);
+ trx_size = max(trx->length, last_subpart + blocksize);
+
+ /*
+ * Skip the TRX data. Decrease offset by block size as
+ * the next loop iteration will increase it.
+ */
+ offset += roundup(trx_size, blocksize) - blocksize;
+ continue;
+ }
+
+ /* Squashfs on devices not using TRX */
+ if (le32_to_cpu(buf[0x000 / 4]) == SQUASHFS_MAGIC ||
+ buf[0x000 / 4] == SHSQ_MAGIC) {
+ bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
+ offset, 0);
+ continue;
+ }
+
+ /*
+ * New (ARM?) devices may have NVRAM in some middle block. Last
+ * block will be checked later, so skip it.
+ */
+ if (offset != master->size - blocksize &&
+ buf[0x000 / 4] == NVRAM_HEADER) {
+ bcm47xxpart_add_part(&parts[curr_part++], "nvram",
+ offset, 0);
+ continue;
+ }
+
+ /* Read middle of the block */
+ err = mtd_read(master, offset + 0x8000, 0x4, &bytes_read,
+ (uint8_t *)buf);
+ if (err && !mtd_is_bitflip(err)) {
+ pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
+ offset, err);
+ continue;
+ }
+
+ /* Some devices (ex. WNDR3700v3) don't have a standard 'MPFR' */
+ if (buf[0x000 / 4] == BOARD_DATA_MAGIC2) {
+ bcm47xxpart_add_part(&parts[curr_part++], "board_data",
+ offset, MTD_WRITEABLE);
+ continue;
+ }
+ }
+
+ /* Look for NVRAM at the end of the last block. */
+ for (i = 0; i < ARRAY_SIZE(possible_nvram_sizes); i++) {
+ if (curr_part >= BCM47XXPART_MAX_PARTS) {
+ pr_warn("Reached maximum number of partitions, scanning stopped!\n");
+ break;
+ }
+
+ offset = master->size - possible_nvram_sizes[i];
+ err = mtd_read(master, offset, 0x4, &bytes_read,
+ (uint8_t *)buf);
+ if (err && !mtd_is_bitflip(err)) {
+ pr_err("mtd_read error while reading (offset 0x%X): %d\n",
+ offset, err);
+ continue;
+ }
+
+ /* Standard NVRAM */
+ if (buf[0] == NVRAM_HEADER) {
+ bcm47xxpart_add_part(&parts[curr_part++], "nvram",
+ master->size - blocksize, 0);
+ break;
+ }
+ }
+
+ kfree(buf);
+
+ /*
+ * Assume that partitions end at the beginning of the one they are
+ * followed by.
+ */
+ for (i = 0; i < curr_part; i++) {
+ u64 next_part_offset = (i < curr_part - 1) ?
+ parts[i + 1].offset : master->size;
+
+ parts[i].size = next_part_offset - parts[i].offset;
+ }
+
+ /* If there was TRX parse it now */
+ for (i = 0; i < trx_num; i++) {
+ struct mtd_partition *trx = &parts[trx_parts[i]];
+
+ if (i == bcm47xxpart_bootpartition())
+ trx->types = trx_types;
+ else
+ trx->name = "failsafe";
+ }
+
+ *pparts = parts;
+ return curr_part;
+};
+
+static const struct of_device_id bcm47xxpart_of_match_table[] = {
+ { .compatible = "brcm,bcm947xx-cfe-partitions" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, bcm47xxpart_of_match_table);
+
+static struct mtd_part_parser bcm47xxpart_mtd_parser = {
+ .parse_fn = bcm47xxpart_parse,
+ .name = "bcm47xxpart",
+ .of_match_table = bcm47xxpart_of_match_table,
+};
+module_mtd_part_parser(bcm47xxpart_mtd_parser);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories");
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