Fixed MTP to work with TWRP

drivers/mtd/bcm47xxpart.c

@@ -0,0 +1,293 @@
+/*
+ * 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>
+
+/* 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 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 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) {
+			if (BCM47XXPART_MAX_PARTS - curr_part < 4) {
+				pr_warn("Not enough partitions left to register trx, scanning stopped!\n");
+				break;
+			}
+
+			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;
+		}
+
+		/*
+		 * 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 */
+		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");