mtd: bcm47part driver for BCM47XX chipsets

This driver provides parser detecting partitions on BCM47XX flash
memories. It has many differences in comparison to BCM63XX, like:
1) Different CFE with no more trivial MAGICs
2) More partitions types (board_data, ML, POT)
3) Supporting more than 1 flash on a device
which resulted in decision of writing new parser.

It uses generic mtd interface and was successfully tested with Netgear
WNDR4500 router which has 2 flash memories: serial one and NAND one.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

3 files changed, 210 insertions, 0 deletions

diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index 27143e042af5..73fcbbeb78d0 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -148,6 +148,13 @@ config MTD_BCM63XX_PARTS
           This provides partions parsing for BCM63xx devices with CFE
           bootloaders.
 
+config MTD_BCM47XX_PARTS
+        tristate "BCM47XX partitioning support"
+        depends on BCM47XX
+        help
+          This provides partitions parser for devices based on BCM47xx
+          boards.
+
 comment "User Modules And Translation Layers"
 
 config MTD_CHAR
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index f90135429dc7..18a38e55b2f0 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_MTD_CMDLINE_PARTS) += cmdlinepart.o
 obj-$(CONFIG_MTD_AFS_PARTS)     += afs.o
 obj-$(CONFIG_MTD_AR7_PARTS)     += ar7part.o
 obj-$(CONFIG_MTD_BCM63XX_PARTS) += bcm63xxpart.o
+obj-$(CONFIG_MTD_BCM47XX_PARTS) += bcm47xxpart.o
 
 # 'Users' - code which presents functionality to userspace.
 obj-$(CONFIG_MTD_CHAR)          += mtdchar.o
diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c
new file mode 100644
index 000000000000..e06d782489a6
--- /dev/null
+++ b/drivers/mtd/bcm47xxpart.c
@@ -0,0 +1,202 @@
+/*
+ * 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 <asm/mach-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 = 0x10000;
+        struct trx_header *trx;
+
+        /* Alloc */
+        parts = kzalloc(sizeof(struct mtd_partition) * BCM47XXPART_MAX_PARTS,
+                        GFP_KERNEL);
+        buf = kzalloc(BCM47XXPART_BYTES_TO_READ, GFP_KERNEL);
+
+        /* 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;
+                }
+
+                /* Standard NVRAM */
+                if (buf[0x000 / 4] == NVRAM_HEADER) {
+                        bcm47xxpart_add_part(&parts[curr_part++], "nvram",
+                                             offset, 0);
+                        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;
+
+                        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++;
+
+                        /*
+                         * 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;
+                }
+        }
+        kfree(buf);
+
+        /*
+         * Assume that partitions end at the beginning of the one they are
+         * followed by.
+         */
+        for (i = 0; i < curr_part - 1; i++)
+                parts[i].size = parts[i + 1].offset - parts[i].offset;
+        if (curr_part > 0)
+                parts[curr_part - 1].size =
+                                master->size - parts[curr_part - 1].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");