[mirror_ubuntu-jammy-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	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 = 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;
		}

		/* CFE has small NVRAM at 0x400 */
		if (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;
		}

		/* 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;
		}
	}

	/* 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)
{
	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");
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	*/
	26	#define BCM47XXPART_BYTES_TO_READ 0x404
	27
3cf7f131 RM	28	/* Magics */
	29	#define BOARD_DATA_MAGIC 0x5246504D /* MPFR */
	30	#define POT_MAGIC1 0x54544f50 /* POTT */
	31	#define POT_MAGIC2 0x504f /* OP */
	32	#define ML_MAGIC1 0x39685a42
	33	#define ML_MAGIC2 0x26594131
	34	#define TRX_MAGIC 0x30524448
	35
	36	struct trx_header {
	37	uint32_t magic;
	38	uint32_t length;
	39	uint32_t crc32;
	40	uint16_t flags;
	41	uint16_t version;
	42	uint32_t offset[3];
	43	} __packed;
	44
	45	static void bcm47xxpart_add_part(struct mtd_partition part, char name,
	46	u64 offset, uint32_t mask_flags)
	47	{
	48	part->name = name;
	49	part->offset = offset;
	50	part->mask_flags = mask_flags;
	51	}
	52
	53	static int bcm47xxpart_parse(struct mtd_info *master,
	54	struct mtd_partition **pparts,
	55	struct mtd_part_parser_data *data)
	56	{
	57	struct mtd_partition *parts;
	58	uint8_t i, curr_part = 0;
	59	uint32_t *buf;
	60	size_t bytes_read;
	61	uint32_t offset;
25bad1d3	62	uint32_t blocksize = master->erasesize;
3cf7f131	63	struct trx_header *trx;
396afe55 RM	64	int trx_part = -1;
396afe55 RM	65	int last_trx_part = -1;
91d542f4	66	int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
3cf7f131	67
25bad1d3 HM	68	if (blocksize <= 0x10000)
25bad1d3 HM	69	blocksize = 0x10000;
3cf7f131 RM	70
	71	/* Alloc */
	72	parts = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
	73	GFP_KERNEL);
99b1d188 HM	74	if (!parts)
	75	return -ENOMEM;
	76
5ca1088f	77	buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);
99b1d188 HM	78	if (!buf) {
	79	kfree(parts);
	80	return -ENOMEM;
	81	}
3cf7f131 RM	82
	83	/* Parse block by block looking for magics */
	84	for (offset = 0; offset <= master->size - blocksize;
	85	offset += blocksize) {
	86	/* Nothing more in higher memory */
	87	if (offset >= 0x2000000)
	88	break;
	89
	90	if (curr_part > BCM47XXPART_MAX_PARTS) {
	91	pr_warn("Reached maximum number of partitions, scanning stopped!\n");
	92	break;
	93	}
	94
	95	/* Read beginning of the block */
5ca1088f	96	if (mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
3cf7f131 RM	97	&bytes_read, (uint8_t *)buf) < 0) {
	98	pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
	99	offset);
	100	continue;
	101	}
	102
	103	/* CFE has small NVRAM at 0x400 */
	104	if (buf[0x400 / 4] == NVRAM_HEADER) {
	105	bcm47xxpart_add_part(&parts[curr_part++], "boot",
	106	offset, MTD_WRITEABLE);
	107	continue;
	108	}
	109
3cf7f131 RM	110	/*
	111	* board_data starts with board_id which differs across boards,
	112	* but we can use 'MPFR' (hopefully) magic at 0x100
	113	*/
	114	if (buf[0x100 / 4] == BOARD_DATA_MAGIC) {
	115	bcm47xxpart_add_part(&parts[curr_part++], "board_data",
	116	offset, MTD_WRITEABLE);
	117	continue;
	118	}
	119
	120	/* POT(TOP) */
	121	if (buf[0x000 / 4] == POT_MAGIC1 &&
	122	(buf[0x004 / 4] & 0xFFFF) == POT_MAGIC2) {
	123	bcm47xxpart_add_part(&parts[curr_part++], "POT", offset,
	124	MTD_WRITEABLE);
	125	continue;
	126	}
	127
	128	/* ML */
	129	if (buf[0x010 / 4] == ML_MAGIC1 &&
	130	buf[0x014 / 4] == ML_MAGIC2) {
	131	bcm47xxpart_add_part(&parts[curr_part++], "ML", offset,
	132	MTD_WRITEABLE);
	133	continue;
	134	}
	135
	136	/* TRX */
	137	if (buf[0x000 / 4] == TRX_MAGIC) {
	138	trx = (struct trx_header *)buf;
	139
396afe55 RM	140	trx_part = curr_part;
	141	bcm47xxpart_add_part(&parts[curr_part++], "firmware",
	142	offset, 0);
	143
3cf7f131 RM	144	i = 0;
	145	/* We have LZMA loader if offset[2] points to sth */
	146	if (trx->offset[2]) {
	147	bcm47xxpart_add_part(&parts[curr_part++],
	148	"loader",
	149	offset + trx->offset[i],
	150	0);
	151	i++;
	152	}
	153
	154	bcm47xxpart_add_part(&parts[curr_part++], "linux",
	155	offset + trx->offset[i], 0);
	156	i++;
	157
	158	/*
	159	* Pure rootfs size is known and can be calculated as:
	160	* trx->length - trx->offset[i]. We don't fill it as
	161	* we want to have jffs2 (overlay) in the same mtd.
	162	*/
	163	bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
	164	offset + trx->offset[i], 0);
	165	i++;
	166
396afe55 RM	167	last_trx_part = curr_part - 1;
396afe55 RM	168
3cf7f131 RM	169	/*
	170	* We have whole TRX scanned, skip to the next part. Use
	171	* roundown (not roundup), as the loop will increase
	172	* offset in next step.
	173	*/
	174	offset = rounddown(offset + trx->length, blocksize);
	175	continue;
	176	}
	177	}
91d542f4 RM	178
	179	/* Look for NVRAM at the end of the last block. */
	180	for (i = 0; i < ARRAY_SIZE(possible_nvram_sizes); i++) {
	181	if (curr_part > BCM47XXPART_MAX_PARTS) {
	182	pr_warn("Reached maximum number of partitions, scanning stopped!\n");
	183	break;
	184	}
	185
	186	offset = master->size - possible_nvram_sizes[i];
	187	if (mtd_read(master, offset, 0x4, &bytes_read,
	188	(uint8_t *)buf) < 0) {
	189	pr_err("mtd_read error while reading at offset 0x%X!\n",
	190	offset);
	191	continue;
	192	}
	193
	194	/* Standard NVRAM */
	195	if (buf[0] == NVRAM_HEADER) {
	196	bcm47xxpart_add_part(&parts[curr_part++], "nvram",
	197	master->size - blocksize, 0);
	198	break;
	199	}
	200	}
	201
3cf7f131 RM	202	kfree(buf);
	203
	204	/*
	205	* Assume that partitions end at the beginning of the one they are
	206	* followed by.
	207	*/
648bdbee RM	208	for (i = 0; i < curr_part; i++) {
	209	u64 next_part_offset = (i < curr_part - 1) ?
	210	parts[i + 1].offset : master->size;
	211
	212	parts[i].size = next_part_offset - parts[i].offset;
396afe55 RM	213	if (i == last_trx_part && trx_part >= 0)
	214	parts[trx_part].size = next_part_offset -
	215	parts[trx_part].offset;
648bdbee	216	}
3cf7f131 RM	217
	218	*pparts = parts;
	219	return curr_part;
	220	};
	221
	222	static struct mtd_part_parser bcm47xxpart_mtd_parser = {
	223	.owner = THIS_MODULE,
	224	.parse_fn = bcm47xxpart_parse,
	225	.name = "bcm47xxpart",
	226	};
	227
	228	static int __init bcm47xxpart_init(void)
	229	{
	230	return register_mtd_parser(&bcm47xxpart_mtd_parser);
	231	}
	232
	233	static void __exit bcm47xxpart_exit(void)
	234	{
	235	deregister_mtd_parser(&bcm47xxpart_mtd_parser);
	236	}
	237
	238	module_init(bcm47xxpart_init);
	239	module_exit(bcm47xxpart_exit);
	240
	241	MODULE_LICENSE("GPL");
	242	MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories");