drivers/mtd/bcm47xxpart.c - linux - Git at Google

 /*
  * 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 = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
 			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");
	/*
	* 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 = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
	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");