[mirror_ubuntu-zesty-kernel.git] / drivers / mtd / bcm47xxpart.c

/*
 * 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 <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	0x4e8

/* Magics */
#define BOARD_DATA_MAGIC		0x5246504D	/* MPFR */
#define BOARD_DATA_MAGIC2		0xBD0D0BBD
#define CFE_MAGIC			0x43464531	/* 1EFC */
#define FACTORY_MAGIC			0x59544346	/* FCTY */
#define POT_MAGIC1			0x54544f50	/* POTT */
#define POT_MAGIC2			0x504f		/* OP */
#define ML_MAGIC1			0x39685a42
#define ML_MAGIC2			0x26594131
#define TRX_MAGIC			0x30524448
#define SQSH_MAGIC			0x71736873	/* shsq */

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 = master->erasesize;
	struct trx_header *trx;
	int trx_part = -1;
	int last_trx_part = -1;
	int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };

	if (blocksize <= 0x10000)
		blocksize = 0x10000;

	/* 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 */
		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;
		}

		/* 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) {
			trx = (struct trx_header *)buf;

			trx_part = curr_part;
			bcm47xxpart_add_part(&parts[curr_part++], "firmware",
					     offset, 0);

			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++;

			last_trx_part = curr_part - 1;

			/*
			 * 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;
		}

		/* Squashfs on devices not using TRX */
		if (buf[0x000 / 4] == SQSH_MAGIC) {
			bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
					     offset, 0);
			continue;
		}

		/* Read middle of the block */
		if (mtd_read(master, offset + 0x8000, 0x4,
			     &bytes_read, (uint8_t *)buf) < 0) {
			pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
			       offset);
			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];
		if (mtd_read(master, offset, 0x4, &bytes_read,
			     (uint8_t *)buf) < 0) {
			pr_err("mtd_read error while reading at offset 0x%X!\n",
			       offset);
			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 (i == last_trx_part && trx_part >= 0)
			parts[trx_part].size = next_part_offset -
					       parts[trx_part].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)
{
	register_mtd_parser(&bcm47xxpart_mtd_parser);
	return 0;
}

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");
Commit	Line	Data
3cf7f131 RM	1	/*
	2	* BCM47XX MTD partitioning
	3	*
	4	* Copyright © 2012 Rafał Miłecki <zajec5@gmail.com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/kernel.h>
	14	#include <linux/slab.h>
	15	#include <linux/mtd/mtd.h>
	16	#include <linux/mtd/partitions.h>
111bd981	17	#include <bcm47xx_nvram.h>
3cf7f131 RM	18
	19	/* 10 parts were found on sflash on Netgear WNDR4500 */
	20	#define BCM47XXPART_MAX_PARTS 12
	21
5ca1088f RM	22	/*
	23	* Amount of bytes we read when analyzing each block of flash memory.
	24	* Set it big enough to allow detecting partition and reading important data.
	25	*/
4f8aaf72	26	#define BCM47XXPART_BYTES_TO_READ 0x4e8
5ca1088f	27
3cf7f131 RM	28	/* Magics */
3cf7f131 RM	29	#define BOARD_DATA_MAGIC 0x5246504D /* MPFR */
f0501e81	30	#define BOARD_DATA_MAGIC2 0xBD0D0BBD
4f8aaf72	31	#define CFE_MAGIC 0x43464531 /* 1EFC */
33094c73	32	#define FACTORY_MAGIC 0x59544346 /* FCTY */
3cf7f131 RM	33	#define POT_MAGIC1 0x54544f50 /* POTT */
	34	#define POT_MAGIC2 0x504f /* OP */
	35	#define ML_MAGIC1 0x39685a42
	36	#define ML_MAGIC2 0x26594131
	37	#define TRX_MAGIC 0x30524448
020c6bcf	38	#define SQSH_MAGIC 0x71736873 /* shsq */
3cf7f131 RM	39
	40	struct trx_header {
	41	uint32_t magic;
	42	uint32_t length;
	43	uint32_t crc32;
	44	uint16_t flags;
	45	uint16_t version;
	46	uint32_t offset[3];
	47	} __packed;
	48
	49	static void bcm47xxpart_add_part(struct mtd_partition part, char name,
	50	u64 offset, uint32_t mask_flags)
	51	{
	52	part->name = name;
	53	part->offset = offset;
	54	part->mask_flags = mask_flags;
	55	}
	56
	57	static int bcm47xxpart_parse(struct mtd_info *master,
	58	struct mtd_partition **pparts,
	59	struct mtd_part_parser_data *data)
	60	{
	61	struct mtd_partition *parts;
	62	uint8_t i, curr_part = 0;
	63	uint32_t *buf;
	64	size_t bytes_read;
	65	uint32_t offset;
25bad1d3	66	uint32_t blocksize = master->erasesize;
3cf7f131	67	struct trx_header *trx;
396afe55 RM	68	int trx_part = -1;
396afe55 RM	69	int last_trx_part = -1;
91d542f4	70	int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
3cf7f131	71
25bad1d3 HM	72	if (blocksize <= 0x10000)
25bad1d3 HM	73	blocksize = 0x10000;
3cf7f131 RM	74
	75	/* Alloc */
	76	parts = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
	77	GFP_KERNEL);
99b1d188 HM	78	if (!parts)
	79	return -ENOMEM;
	80
5ca1088f	81	buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);
99b1d188 HM	82	if (!buf) {
	83	kfree(parts);
	84	return -ENOMEM;
	85	}
3cf7f131 RM	86
	87	/* Parse block by block looking for magics */
	88	for (offset = 0; offset <= master->size - blocksize;
	89	offset += blocksize) {
	90	/* Nothing more in higher memory */
	91	if (offset >= 0x2000000)
	92	break;
	93
	94	if (curr_part > BCM47XXPART_MAX_PARTS) {
	95	pr_warn("Reached maximum number of partitions, scanning stopped!\n");
	96	break;
	97	}
	98
	99	/* Read beginning of the block */
5ca1088f	100	if (mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
3cf7f131 RM	101	&bytes_read, (uint8_t *)buf) < 0) {
	102	pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
	103	offset);
	104	continue;
	105	}
	106
4f8aaf72 RM	107	/* Magic or small NVRAM at 0x400 */
	108	if ((buf[0x4e0 / 4] == CFE_MAGIC && buf[0x4e4 / 4] == CFE_MAGIC) \|\|
	109	(buf[0x400 / 4] == NVRAM_HEADER)) {
3cf7f131 RM	110	bcm47xxpart_add_part(&parts[curr_part++], "boot",
	111	offset, MTD_WRITEABLE);
	112	continue;
	113	}
	114
3cf7f131 RM	115	/*
	116	* board_data starts with board_id which differs across boards,
	117	* but we can use 'MPFR' (hopefully) magic at 0x100
	118	*/
	119	if (buf[0x100 / 4] == BOARD_DATA_MAGIC) {
	120	bcm47xxpart_add_part(&parts[curr_part++], "board_data",
	121	offset, MTD_WRITEABLE);
	122	continue;
	123	}
	124
33094c73 RM	125	/* Found on Huawei E970 */
	126	if (buf[0x000 / 4] == FACTORY_MAGIC) {
	127	bcm47xxpart_add_part(&parts[curr_part++], "factory",
	128	offset, MTD_WRITEABLE);
	129	continue;
	130	}
	131
3cf7f131 RM	132	/* POT(TOP) */
	133	if (buf[0x000 / 4] == POT_MAGIC1 &&
	134	(buf[0x004 / 4] & 0xFFFF) == POT_MAGIC2) {
	135	bcm47xxpart_add_part(&parts[curr_part++], "POT", offset,
	136	MTD_WRITEABLE);
	137	continue;
	138	}
	139
	140	/* ML */
	141	if (buf[0x010 / 4] == ML_MAGIC1 &&
	142	buf[0x014 / 4] == ML_MAGIC2) {
	143	bcm47xxpart_add_part(&parts[curr_part++], "ML", offset,
	144	MTD_WRITEABLE);
	145	continue;
	146	}
	147
	148	/* TRX */
	149	if (buf[0x000 / 4] == TRX_MAGIC) {
	150	trx = (struct trx_header *)buf;
	151
396afe55 RM	152	trx_part = curr_part;
	153	bcm47xxpart_add_part(&parts[curr_part++], "firmware",
	154	offset, 0);
	155
3cf7f131 RM	156	i = 0;
	157	/* We have LZMA loader if offset[2] points to sth */
	158	if (trx->offset[2]) {
	159	bcm47xxpart_add_part(&parts[curr_part++],
	160	"loader",
	161	offset + trx->offset[i],
	162	0);
	163	i++;
	164	}
	165
	166	bcm47xxpart_add_part(&parts[curr_part++], "linux",
	167	offset + trx->offset[i], 0);
	168	i++;
	169
	170	/*
	171	* Pure rootfs size is known and can be calculated as:
	172	* trx->length - trx->offset[i]. We don't fill it as
	173	* we want to have jffs2 (overlay) in the same mtd.
	174	*/
	175	bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
	176	offset + trx->offset[i], 0);
	177	i++;
	178
396afe55 RM	179	last_trx_part = curr_part - 1;
396afe55 RM	180
3cf7f131 RM	181	/*
	182	* We have whole TRX scanned, skip to the next part. Use
	183	* roundown (not roundup), as the loop will increase
	184	* offset in next step.
	185	*/
	186	offset = rounddown(offset + trx->length, blocksize);
	187	continue;
	188	}
020c6bcf RM	189
	190	/* Squashfs on devices not using TRX */
	191	if (buf[0x000 / 4] == SQSH_MAGIC) {
	192	bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
	193	offset, 0);
	194	continue;
	195	}
f0501e81 RM	196
	197	/* Read middle of the block */
	198	if (mtd_read(master, offset + 0x8000, 0x4,
	199	&bytes_read, (uint8_t *)buf) < 0) {
	200	pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
	201	offset);
	202	continue;
	203	}
	204
	205	/* Some devices (ex. WNDR3700v3) don't have a standard 'MPFR' */
	206	if (buf[0x000 / 4] == BOARD_DATA_MAGIC2) {
	207	bcm47xxpart_add_part(&parts[curr_part++], "board_data",
	208	offset, MTD_WRITEABLE);
	209	continue;
	210	}
3cf7f131	211	}
91d542f4 RM	212
	213	/* Look for NVRAM at the end of the last block. */
	214	for (i = 0; i < ARRAY_SIZE(possible_nvram_sizes); i++) {
	215	if (curr_part > BCM47XXPART_MAX_PARTS) {
	216	pr_warn("Reached maximum number of partitions, scanning stopped!\n");
	217	break;
	218	}
	219
	220	offset = master->size - possible_nvram_sizes[i];
	221	if (mtd_read(master, offset, 0x4, &bytes_read,
	222	(uint8_t *)buf) < 0) {
	223	pr_err("mtd_read error while reading at offset 0x%X!\n",
	224	offset);
	225	continue;
	226	}
	227
	228	/* Standard NVRAM */
	229	if (buf[0] == NVRAM_HEADER) {
	230	bcm47xxpart_add_part(&parts[curr_part++], "nvram",
	231	master->size - blocksize, 0);
	232	break;
	233	}
	234	}
	235
3cf7f131 RM	236	kfree(buf);
	237
	238	/*
	239	* Assume that partitions end at the beginning of the one they are
	240	* followed by.
	241	*/
648bdbee RM	242	for (i = 0; i < curr_part; i++) {
	243	u64 next_part_offset = (i < curr_part - 1) ?
	244	parts[i + 1].offset : master->size;
	245
	246	parts[i].size = next_part_offset - parts[i].offset;
396afe55 RM	247	if (i == last_trx_part && trx_part >= 0)
	248	parts[trx_part].size = next_part_offset -
	249	parts[trx_part].offset;
648bdbee	250	}
3cf7f131 RM	251
	252	*pparts = parts;
	253	return curr_part;
	254	};
	255
	256	static struct mtd_part_parser bcm47xxpart_mtd_parser = {
	257	.owner = THIS_MODULE,
	258	.parse_fn = bcm47xxpart_parse,
	259	.name = "bcm47xxpart",
	260	};
	261
	262	static int __init bcm47xxpart_init(void)
	263	{
6e14a61d AL	264	register_mtd_parser(&bcm47xxpart_mtd_parser);
6e14a61d AL	265	return 0;
3cf7f131 RM	266	}
	267
	268	static void __exit bcm47xxpart_exit(void)
	269	{
	270	deregister_mtd_parser(&bcm47xxpart_mtd_parser);
	271	}
	272
	273	module_init(bcm47xxpart_init);
	274	module_exit(bcm47xxpart_exit);
	275
	276	MODULE_LICENSE("GPL");
	277	MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories");