[mirror_ubuntu-artful-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/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;

			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);

			/* Jump to the end of TRX */
			trx = (struct trx_header *)buf;
			offset = roundup(offset + trx->length, blocksize);
			/* Next loop iteration will increase the offset */
			offset -= 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 struct mtd_part_parser bcm47xxpart_mtd_parser = {
	.parse_fn = bcm47xxpart_parse,
	.name = "bcm47xxpart",
};
module_mtd_part_parser(bcm47xxpart_mtd_parser);

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
89a0d9a9	12	#include <linux/bcm47xx_nvram.h>
3cf7f131 RM	13	#include <linux/module.h>
	14	#include <linux/kernel.h>
	15	#include <linux/slab.h>
	16	#include <linux/mtd/mtd.h>
	17	#include <linux/mtd/partitions.h>
3cf7f131	18
0b56d2d4 RM	19	#include <uapi/linux/magic.h>
0b56d2d4 RM	20
59af5c7a RM	21	/*
	22	* NAND flash on Netgear R6250 was verified to contain 15 partitions.
	23	* This will result in allocating too big array for some old devices, but the
	24	* memory will be freed soon anyway (see mtd_device_parse_register).
	25	*/
	26	#define BCM47XXPART_MAX_PARTS 20
3cf7f131	27
5ca1088f RM	28	/*
	29	* Amount of bytes we read when analyzing each block of flash memory.
	30	* Set it big enough to allow detecting partition and reading important data.
	31	*/
4f8aaf72	32	#define BCM47XXPART_BYTES_TO_READ 0x4e8
5ca1088f	33
3cf7f131 RM	34	/* Magics */
3cf7f131 RM	35	#define BOARD_DATA_MAGIC 0x5246504D /* MPFR */
f0501e81	36	#define BOARD_DATA_MAGIC2 0xBD0D0BBD
4f8aaf72	37	#define CFE_MAGIC 0x43464531 /* 1EFC */
33094c73	38	#define FACTORY_MAGIC 0x59544346 /* FCTY */
9e3afa5f	39	#define NVRAM_HEADER 0x48534C46 /* FLSH */
3cf7f131 RM	40	#define POT_MAGIC1 0x54544f50 /* POTT */
	41	#define POT_MAGIC2 0x504f /* OP */
	42	#define ML_MAGIC1 0x39685a42
	43	#define ML_MAGIC2 0x26594131
	44	#define TRX_MAGIC 0x30524448
0b56d2d4	45	#define SHSQ_MAGIC 0x71736873 /* shsq (weird ZTE H218N endianness) */
99352afe RM	46
99352afe RM	47	static const char * const trx_types[] = { "trx", NULL };
3cf7f131 RM	48
	49	struct trx_header {
	50	uint32_t magic;
	51	uint32_t length;
	52	uint32_t crc32;
	53	uint16_t flags;
	54	uint16_t version;
	55	uint32_t offset[3];
	56	} __packed;
	57
bd10c26a	58	static void bcm47xxpart_add_part(struct mtd_partition part, const char name,
3cf7f131 RM	59	u64 offset, uint32_t mask_flags)
	60	{
	61	part->name = name;
	62	part->offset = offset;
	63	part->mask_flags = mask_flags;
	64	}
	65
89a0d9a9 RM	66	/**
	67	* bcm47xxpart_bootpartition - gets index of TRX partition used by bootloader
	68	*
	69	* Some devices may have more than one TRX partition. In such case one of them
	70	* is the main one and another a failsafe one. Bootloader may fallback to the
	71	* failsafe firmware if it detects corruption of the main image.
	72	*
	73	* This function provides info about currently used TRX partition. It's the one
	74	* containing kernel started by the bootloader.
	75	*/
	76	static int bcm47xxpart_bootpartition(void)
	77	{
	78	char buf[4];
	79	int bootpartition;
	80
	81	/* Check CFE environment variable */
	82	if (bcm47xx_nvram_getenv("bootpartition", buf, sizeof(buf)) > 0) {
	83	if (!kstrtoint(buf, 0, &bootpartition))
	84	return bootpartition;
	85	}
	86
	87	return 0;
	88	}
	89
3cf7f131	90	static int bcm47xxpart_parse(struct mtd_info *master,
b9adf469	91	const struct mtd_partition **pparts,
3cf7f131 RM	92	struct mtd_part_parser_data *data)
	93	{
	94	struct mtd_partition *parts;
	95	uint8_t i, curr_part = 0;
	96	uint32_t *buf;
	97	size_t bytes_read;
	98	uint32_t offset;
25bad1d3	99	uint32_t blocksize = master->erasesize;
89a0d9a9 RM	100	int trx_parts[2]; /* Array with indexes of TRX partitions */
89a0d9a9 RM	101	int trx_num = 0; /* Number of found TRX partitions */
91d542f4	102	int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
36bcc0c9	103	int err;
3cf7f131	104
16bd87b3 RM	105	/*
	106	* Some really old flashes (like AT45DB*) had smaller erasesize-s, but
	107	* partitions were aligned to at least 0x1000 anyway.
	108	*/
	109	if (blocksize < 0x1000)
	110	blocksize = 0x1000;
3cf7f131 RM	111
	112	/* Alloc */
	113	parts = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
	114	GFP_KERNEL);
99b1d188 HM	115	if (!parts)
	116	return -ENOMEM;
	117
5ca1088f	118	buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);
99b1d188 HM	119	if (!buf) {
	120	kfree(parts);
	121	return -ENOMEM;
	122	}
3cf7f131 RM	123
	124	/* Parse block by block looking for magics */
	125	for (offset = 0; offset <= master->size - blocksize;
	126	offset += blocksize) {
2a36a5c3	127	/* Nothing more in higher memory on BCM47XX (MIPS) */
97f2645f	128	if (IS_ENABLED(CONFIG_BCM47XX) && offset >= 0x2000000)
3cf7f131 RM	129	break;
3cf7f131 RM	130
00b79860	131	if (curr_part >= BCM47XXPART_MAX_PARTS) {
3cf7f131 RM	132	pr_warn("Reached maximum number of partitions, scanning stopped!\n");
	133	break;
	134	}
	135
	136	/* Read beginning of the block */
36bcc0c9 RM	137	err = mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
	138	&bytes_read, (uint8_t *)buf);
	139	if (err && !mtd_is_bitflip(err)) {
	140	pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
	141	offset, err);
3cf7f131 RM	142	continue;
	143	}
	144
4f8aaf72 RM	145	/* Magic or small NVRAM at 0x400 */
	146	if ((buf[0x4e0 / 4] == CFE_MAGIC && buf[0x4e4 / 4] == CFE_MAGIC) \|\|
	147	(buf[0x400 / 4] == NVRAM_HEADER)) {
3cf7f131 RM	148	bcm47xxpart_add_part(&parts[curr_part++], "boot",
	149	offset, MTD_WRITEABLE);
	150	continue;
	151	}
	152
3cf7f131 RM	153	/*
	154	* board_data starts with board_id which differs across boards,
	155	* but we can use 'MPFR' (hopefully) magic at 0x100
	156	*/
	157	if (buf[0x100 / 4] == BOARD_DATA_MAGIC) {
	158	bcm47xxpart_add_part(&parts[curr_part++], "board_data",
	159	offset, MTD_WRITEABLE);
	160	continue;
	161	}
	162
33094c73 RM	163	/* Found on Huawei E970 */
	164	if (buf[0x000 / 4] == FACTORY_MAGIC) {
	165	bcm47xxpart_add_part(&parts[curr_part++], "factory",
	166	offset, MTD_WRITEABLE);
	167	continue;
	168	}
	169
3cf7f131 RM	170	/* POT(TOP) */
	171	if (buf[0x000 / 4] == POT_MAGIC1 &&
	172	(buf[0x004 / 4] & 0xFFFF) == POT_MAGIC2) {
	173	bcm47xxpart_add_part(&parts[curr_part++], "POT", offset,
	174	MTD_WRITEABLE);
	175	continue;
	176	}
	177
	178	/* ML */
	179	if (buf[0x010 / 4] == ML_MAGIC1 &&
	180	buf[0x014 / 4] == ML_MAGIC2) {
	181	bcm47xxpart_add_part(&parts[curr_part++], "ML", offset,
	182	MTD_WRITEABLE);
	183	continue;
	184	}
	185
	186	/* TRX */
	187	if (buf[0x000 / 4] == TRX_MAGIC) {
b522d7b0	188	struct trx_header *trx;
3cf7f131	189
89a0d9a9 RM	190	if (trx_num >= ARRAY_SIZE(trx_parts))
	191	pr_warn("No enough space to store another TRX found at 0x%X\n",
	192	offset);
	193	else
	194	trx_parts[trx_num++] = curr_part;
396afe55 RM	195	bcm47xxpart_add_part(&parts[curr_part++], "firmware",
	196	offset, 0);
	197
bd5d2131	198	/* Jump to the end of TRX */
b522d7b0	199	trx = (struct trx_header *)buf;
bd5d2131 RM	200	offset = roundup(offset + trx->length, blocksize);
	201	/* Next loop iteration will increase the offset */
	202	offset -= blocksize;
3cf7f131 RM	203	continue;
3cf7f131 RM	204	}
020c6bcf RM	205
020c6bcf RM	206	/* Squashfs on devices not using TRX */
0b56d2d4 RM	207	if (le32_to_cpu(buf[0x000 / 4]) == SQUASHFS_MAGIC \|\|
0b56d2d4 RM	208	buf[0x000 / 4] == SHSQ_MAGIC) {
020c6bcf RM	209	bcm47xxpart_add_part(&parts[curr_part++], "rootfs",
	210	offset, 0);
	211	continue;
024629fd RM	212	}
	213
	214	/*
	215	* New (ARM?) devices may have NVRAM in some middle block. Last
	216	* block will be checked later, so skip it.
	217	*/
	218	if (offset != master->size - blocksize &&
	219	buf[0x000 / 4] == NVRAM_HEADER) {
	220	bcm47xxpart_add_part(&parts[curr_part++], "nvram",
	221	offset, 0);
	222	continue;
020c6bcf	223	}
f0501e81 RM	224
f0501e81 RM	225	/* Read middle of the block */
36bcc0c9 RM	226	err = mtd_read(master, offset + 0x8000, 0x4, &bytes_read,
	227	(uint8_t *)buf);
	228	if (err && !mtd_is_bitflip(err)) {
	229	pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
	230	offset, err);
f0501e81 RM	231	continue;
	232	}
	233
	234	/* Some devices (ex. WNDR3700v3) don't have a standard 'MPFR' */
	235	if (buf[0x000 / 4] == BOARD_DATA_MAGIC2) {
	236	bcm47xxpart_add_part(&parts[curr_part++], "board_data",
	237	offset, MTD_WRITEABLE);
	238	continue;
	239	}
3cf7f131	240	}
91d542f4 RM	241
	242	/* Look for NVRAM at the end of the last block. */
	243	for (i = 0; i < ARRAY_SIZE(possible_nvram_sizes); i++) {
00b79860	244	if (curr_part >= BCM47XXPART_MAX_PARTS) {
91d542f4 RM	245	pr_warn("Reached maximum number of partitions, scanning stopped!\n");
	246	break;
	247	}
	248
	249	offset = master->size - possible_nvram_sizes[i];
36bcc0c9 RM	250	err = mtd_read(master, offset, 0x4, &bytes_read,
	251	(uint8_t *)buf);
	252	if (err && !mtd_is_bitflip(err)) {
	253	pr_err("mtd_read error while reading (offset 0x%X): %d\n",
	254	offset, err);
91d542f4 RM	255	continue;
	256	}
	257
	258	/* Standard NVRAM */
	259	if (buf[0] == NVRAM_HEADER) {
	260	bcm47xxpart_add_part(&parts[curr_part++], "nvram",
	261	master->size - blocksize, 0);
	262	break;
	263	}
	264	}
	265
3cf7f131 RM	266	kfree(buf);
	267
	268	/*
	269	* Assume that partitions end at the beginning of the one they are
	270	* followed by.
	271	*/
648bdbee RM	272	for (i = 0; i < curr_part; i++) {
	273	u64 next_part_offset = (i < curr_part - 1) ?
	274	parts[i + 1].offset : master->size;
	275
	276	parts[i].size = next_part_offset - parts[i].offset;
b522d7b0 RM	277	}
	278
	279	/* If there was TRX parse it now */
89a0d9a9 RM	280	for (i = 0; i < trx_num; i++) {
	281	struct mtd_partition *trx = &parts[trx_parts[i]];
	282
99352afe RM	283	if (i == bcm47xxpart_bootpartition())
	284	trx->types = trx_types;
	285	else
89a0d9a9	286	trx->name = "failsafe";
648bdbee	287	}
3cf7f131 RM	288
	289	*pparts = parts;
	290	return curr_part;
	291	};
	292
	293	static struct mtd_part_parser bcm47xxpart_mtd_parser = {
3cf7f131 RM	294	.parse_fn = bcm47xxpart_parse,
	295	.name = "bcm47xxpart",
	296	};
b8f70bad	297	module_mtd_part_parser(bcm47xxpart_mtd_parser);
3cf7f131 RM	298
	299	MODULE_LICENSE("GPL");
	300	MODULE_DESCRIPTION("MTD partitioning for BCM47XX flash memories");