[GitHub/LineageOS/android_kernel_motorola_exynos9610.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
#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;
		}

		/* 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;
		}

		/* Squashfs on devices not using TRX */
		if (buf[0x000 / 4] == SQSH_MAGIC) {
			bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
					     offset, 0);
			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
020c6bcf	35	#define SQSH_MAGIC 0x71736873 /* shsq */
3cf7f131 RM	36
	37	struct trx_header {
	38	uint32_t magic;
	39	uint32_t length;
	40	uint32_t crc32;
	41	uint16_t flags;
	42	uint16_t version;
	43	uint32_t offset[3];
	44	} __packed;
	45
	46	static void bcm47xxpart_add_part(struct mtd_partition part, char name,
	47	u64 offset, uint32_t mask_flags)
	48	{
	49	part->name = name;
	50	part->offset = offset;
	51	part->mask_flags = mask_flags;
	52	}
	53
	54	static int bcm47xxpart_parse(struct mtd_info *master,
	55	struct mtd_partition **pparts,
	56	struct mtd_part_parser_data *data)
	57	{
	58	struct mtd_partition *parts;
	59	uint8_t i, curr_part = 0;
	60	uint32_t *buf;
	61	size_t bytes_read;
	62	uint32_t offset;
25bad1d3	63	uint32_t blocksize = master->erasesize;
3cf7f131	64	struct trx_header *trx;
396afe55 RM	65	int trx_part = -1;
396afe55 RM	66	int last_trx_part = -1;
91d542f4	67	int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
3cf7f131	68
25bad1d3 HM	69	if (blocksize <= 0x10000)
25bad1d3 HM	70	blocksize = 0x10000;
3cf7f131 RM	71
	72	/* Alloc */
	73	parts = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
	74	GFP_KERNEL);
99b1d188 HM	75	if (!parts)
	76	return -ENOMEM;
	77
5ca1088f	78	buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);
99b1d188 HM	79	if (!buf) {
	80	kfree(parts);
	81	return -ENOMEM;
	82	}
3cf7f131 RM	83
	84	/* Parse block by block looking for magics */
	85	for (offset = 0; offset <= master->size - blocksize;
	86	offset += blocksize) {
	87	/* Nothing more in higher memory */
	88	if (offset >= 0x2000000)
	89	break;
	90
	91	if (curr_part > BCM47XXPART_MAX_PARTS) {
	92	pr_warn("Reached maximum number of partitions, scanning stopped!\n");
	93	break;
	94	}
	95
	96	/* Read beginning of the block */
5ca1088f	97	if (mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
3cf7f131 RM	98	&bytes_read, (uint8_t *)buf) < 0) {
	99	pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
	100	offset);
	101	continue;
	102	}
	103
	104	/* CFE has small NVRAM at 0x400 */
	105	if (buf[0x400 / 4] == NVRAM_HEADER) {
	106	bcm47xxpart_add_part(&parts[curr_part++], "boot",
	107	offset, MTD_WRITEABLE);
	108	continue;
	109	}
	110
3cf7f131 RM	111	/*
	112	* board_data starts with board_id which differs across boards,
	113	* but we can use 'MPFR' (hopefully) magic at 0x100
	114	*/
	115	if (buf[0x100 / 4] == BOARD_DATA_MAGIC) {
	116	bcm47xxpart_add_part(&parts[curr_part++], "board_data",
	117	offset, MTD_WRITEABLE);
	118	continue;
	119	}
	120
	121	/* POT(TOP) */
	122	if (buf[0x000 / 4] == POT_MAGIC1 &&
	123	(buf[0x004 / 4] & 0xFFFF) == POT_MAGIC2) {
	124	bcm47xxpart_add_part(&parts[curr_part++], "POT", offset,
	125	MTD_WRITEABLE);
	126	continue;
	127	}
	128
	129	/* ML */
	130	if (buf[0x010 / 4] == ML_MAGIC1 &&
	131	buf[0x014 / 4] == ML_MAGIC2) {
	132	bcm47xxpart_add_part(&parts[curr_part++], "ML", offset,
	133	MTD_WRITEABLE);
	134	continue;
	135	}
	136
	137	/* TRX */
	138	if (buf[0x000 / 4] == TRX_MAGIC) {
	139	trx = (struct trx_header *)buf;
	140
396afe55 RM	141	trx_part = curr_part;
	142	bcm47xxpart_add_part(&parts[curr_part++], "firmware",
	143	offset, 0);
	144
3cf7f131 RM	145	i = 0;
	146	/* We have LZMA loader if offset[2] points to sth */
	147	if (trx->offset[2]) {
	148	bcm47xxpart_add_part(&parts[curr_part++],
	149	"loader",
	150	offset + trx->offset[i],
	151	0);
	152	i++;
	153	}
	154
	155	bcm47xxpart_add_part(&parts[curr_part++], "linux",
	156	offset + trx->offset[i], 0);
	157	i++;
	158
	159	/*
	160	* Pure rootfs size is known and can be calculated as:
	161	* trx->length - trx->offset[i]. We don't fill it as
	162	* we want to have jffs2 (overlay) in the same mtd.
	163	*/
	164	bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
	165	offset + trx->offset[i], 0);
	166	i++;
	167
396afe55 RM	168	last_trx_part = curr_part - 1;
396afe55 RM	169
3cf7f131 RM	170	/*
	171	* We have whole TRX scanned, skip to the next part. Use
	172	* roundown (not roundup), as the loop will increase
	173	* offset in next step.
	174	*/
	175	offset = rounddown(offset + trx->length, blocksize);
	176	continue;
	177	}
020c6bcf RM	178
	179	/* Squashfs on devices not using TRX */
	180	if (buf[0x000 / 4] == SQSH_MAGIC) {
	181	bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
	182	offset, 0);
	183	continue;
	184	}
3cf7f131	185	}
91d542f4 RM	186
	187	/* Look for NVRAM at the end of the last block. */
	188	for (i = 0; i < ARRAY_SIZE(possible_nvram_sizes); i++) {
	189	if (curr_part > BCM47XXPART_MAX_PARTS) {
	190	pr_warn("Reached maximum number of partitions, scanning stopped!\n");
	191	break;
	192	}
	193
	194	offset = master->size - possible_nvram_sizes[i];
	195	if (mtd_read(master, offset, 0x4, &bytes_read,
	196	(uint8_t *)buf) < 0) {
	197	pr_err("mtd_read error while reading at offset 0x%X!\n",
	198	offset);
	199	continue;
	200	}
	201
	202	/* Standard NVRAM */
	203	if (buf[0] == NVRAM_HEADER) {
	204	bcm47xxpart_add_part(&parts[curr_part++], "nvram",
	205	master->size - blocksize, 0);
	206	break;
	207	}
	208	}
	209
3cf7f131 RM	210	kfree(buf);
	211
	212	/*
	213	* Assume that partitions end at the beginning of the one they are
	214	* followed by.
	215	*/
648bdbee RM	216	for (i = 0; i < curr_part; i++) {
	217	u64 next_part_offset = (i < curr_part - 1) ?
	218	parts[i + 1].offset : master->size;
	219
	220	parts[i].size = next_part_offset - parts[i].offset;
396afe55 RM	221	if (i == last_trx_part && trx_part >= 0)
	222	parts[trx_part].size = next_part_offset -
	223	parts[trx_part].offset;
648bdbee	224	}
3cf7f131 RM	225
	226	*pparts = parts;
	227	return curr_part;
	228	};
	229
	230	static struct mtd_part_parser bcm47xxpart_mtd_parser = {
	231	.owner = THIS_MODULE,
	232	.parse_fn = bcm47xxpart_parse,
	233	.name = "bcm47xxpart",
	234	};
	235
	236	static int __init bcm47xxpart_init(void)
	237	{
	238	return register_mtd_parser(&bcm47xxpart_mtd_parser);
	239	}
	240
	241	static void __exit bcm47xxpart_exit(void)
	242	{
	243	deregister_mtd_parser(&bcm47xxpart_mtd_parser);
	244	}
	245
	246	module_init(bcm47xxpart_init);
	247	module_exit(bcm47xxpart_exit);
	248
	249	MODULE_LICENSE("GPL");
	250	MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories");