kernel: mtdsplit: add support for WRGG images

Support splitting WRGG images, found in some D-Link devices (e.g.
DAP-2695).

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
Acked-by: John Crispin <john@phrozen.org>

target/linux/ar71xx/config-4.4

@@ -353,6 +353,7 @@ CONFIG_MTD_SPLIT_FIRMWARE=y
 CONFIG_MTD_SPLIT_LZMA_FW=y
 CONFIG_MTD_SPLIT_SEAMA_FW=y
 CONFIG_MTD_SPLIT_UIMAGE_FW=y
+CONFIG_MTD_SPLIT_WRGG_FW=y
 CONFIG_MTD_TPLINK_PARTS=y
 CONFIG_MYLOADER=y
 CONFIG_NEED_DMA_MAP_STATE=y

target/linux/generic/config-3.18

@@ -2282,6 +2282,7 @@ CONFIG_MTD_SPLIT_SUPPORT=y
 # CONFIG_MTD_SPLIT_TRX_FW is not set
 # CONFIG_MTD_SPLIT_TPLINK_FW is not set
 # CONFIG_MTD_SPLIT_UIMAGE_FW is not set
+# CONFIG_MTD_SPLIT_WRGG_FW is not set
 # CONFIG_MTD_SST25L is not set
 # CONFIG_MTD_SWAP is not set
 # CONFIG_MTD_TESTS is not set

target/linux/generic/config-4.1

@@ -2375,6 +2375,7 @@ CONFIG_MTD_SPLIT_SUPPORT=y
 # CONFIG_MTD_SPLIT_TRX_FW is not set
 # CONFIG_MTD_SPLIT_TPLINK_FW is not set
 # CONFIG_MTD_SPLIT_UIMAGE_FW is not set
+# CONFIG_MTD_SPLIT_WRGG_FW is not set
 # CONFIG_MTD_SST25L is not set
 # CONFIG_MTD_SWAP is not set
 # CONFIG_MTD_TESTS is not set

target/linux/generic/config-4.4

@@ -2365,6 +2365,7 @@ CONFIG_MTD_SPLIT_SUPPORT=y
 # CONFIG_MTD_SPLIT_TPLINK_FW is not set
 # CONFIG_MTD_SPLIT_TRX_FW is not set
 # CONFIG_MTD_SPLIT_UIMAGE_FW is not set
+# CONFIG_MTD_SPLIT_WRGG_FW is not set
 # CONFIG_MTD_SST25L is not set
 # CONFIG_MTD_SWAP is not set
 # CONFIG_MTD_TESTS is not set

target/linux/generic/files/drivers/mtd/mtdsplit/Kconfig

@@ -25,6 +25,11 @@ config MTD_SPLIT_SEAMA_FW
 	depends on MTD_SPLIT_SUPPORT
 	select MTD_SPLIT
 
+config MTD_SPLIT_WRGG_FW
+	bool "WRGG firmware parser"
+	depends on MTD_SPLIT_SUPPORT
+	select MTD_SPLIT
+
 config MTD_SPLIT_UIMAGE_FW
 	bool "uImage based firmware partition parser"
 	depends on MTD_SPLIT_SUPPORT

target/linux/generic/files/drivers/mtd/mtdsplit/Makefile

@@ -8,3 +8,4 @@ obj-$(CONFIG_MTD_SPLIT_TPLINK_FW) += mtdsplit_tplink.o
 obj-$(CONFIG_MTD_SPLIT_TRX_FW) += mtdsplit_trx.o
 obj-$(CONFIG_MTD_SPLIT_BRNIMAGE_FW) += mtdsplit_brnimage.o
 obj-$(CONFIG_MTD_SPLIT_EVA_FW) += mtdsplit_eva.o
+obj-$(CONFIG_MTD_SPLIT_WRGG_FW) += mtdsplit_wrgg.o

target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_wrgg.c

@@ -0,0 +1,109 @@
+/*
+ *  Copyright (C) 2013 Gabor Juhos <juhosg@openwrt.org>
+ *  Copyright (C) 2014 Felix Fietkau <nbd@nbd.name>
+ *  Copyright (C) 2016 Stijn Tintel <stijn@linux-ipv6.be>
+ *
+ *  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/init.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/byteorder/generic.h>
+
+#include "mtdsplit.h"
+
+#define WRGG_NR_PARTS		2
+#define WRGG_MIN_ROOTFS_OFFS	0x80000	/* 512KiB */
+#define WRGG03_MAGIC		0x20080321
+
+struct wrgg03_header {
+	char		signature[32];
+	uint32_t	magic1;
+	uint32_t	magic2;
+	char		version[16];
+	char		model[16];
+	uint32_t	flag[2];
+	uint32_t	reserve[2];
+	char		buildno[16];
+	uint32_t	size;
+	uint32_t	offset;
+	char		devname[32];
+	char		digest[16];
+} __attribute__ ((packed));
+
+
+static int mtdsplit_parse_wrgg(struct mtd_info *master,
+				struct mtd_partition **pparts,
+				struct mtd_part_parser_data *data)
+{
+	struct wrgg03_header hdr;
+	size_t hdr_len, retlen, kernel_ent_size;
+	size_t rootfs_offset;
+	struct mtd_partition *parts;
+	enum mtdsplit_part_type type;
+	int err;
+
+	hdr_len = sizeof(hdr);
+	err = mtd_read(master, 0, hdr_len, &retlen, (void *) &hdr);
+	if (err)
+		return err;
+
+	if (retlen != hdr_len)
+		return -EIO;
+
+	/* sanity checks */
+	if (le32_to_cpu(hdr.magic1) != WRGG03_MAGIC)
+		return -EINVAL;
+
+	kernel_ent_size = hdr_len + be32_to_cpu(hdr.size);
+
+	if (kernel_ent_size > master->size)
+		return -EINVAL;
+
+	/*
+	 * The size in the header covers the rootfs as well.
+	 * Start the search from an arbitrary offset.
+	 */
+	err = mtd_find_rootfs_from(master, WRGG_MIN_ROOTFS_OFFS,
+				   master->size, &rootfs_offset, &type);
+	if (err)
+		return err;
+
+	parts = kzalloc(WRGG_NR_PARTS * sizeof(*parts), GFP_KERNEL);
+	if (!parts)
+		return -ENOMEM;
+
+	parts[0].name = KERNEL_PART_NAME;
+	parts[0].offset = 0;
+	parts[0].size = rootfs_offset;
+
+	parts[1].name = ROOTFS_PART_NAME;
+	parts[1].offset = rootfs_offset;
+	parts[1].size = master->size - rootfs_offset;
+
+	*pparts = parts;
+	return WRGG_NR_PARTS;
+}
+
+static struct mtd_part_parser mtdsplit_wrgg_parser = {
+	.owner = THIS_MODULE,
+	.name = "wrgg-fw",
+	.parse_fn = mtdsplit_parse_wrgg,
+	.type = MTD_PARSER_TYPE_FIRMWARE,
+};
+
+static int __init mtdsplit_wrgg_init(void)
+{
+	register_mtd_parser(&mtdsplit_wrgg_parser);
+
+	return 0;
+}
+
+subsys_initcall(mtdsplit_wrgg_init);