[PATCH 2/2] mtd: extract TRX parser out of bcm47xxpart into separated module

[RafaÅ MiÅecki]

This makes TRX parsing code reusable with other platforms and parsers.
There is still some place for improvement (e.g. working on some smarter
method of checking rootfs format), for now we simply move the code as it
is.

Signed-off-by: RafaÅ MiÅecki <zajec5@xxxxxxxxx>
---
 drivers/mtd/Kconfig              |   4 ++
 drivers/mtd/Makefile             |   1 +
 drivers/mtd/bcm47xxpart.c        |  63 +--------------------
 drivers/mtd/parsers/Kconfig      |   8 +++
 drivers/mtd/parsers/Makefile     |   1 +
 drivers/mtd/parsers/parser_trx.c | 119 +++++++++++++++++++++++++++++++++++++++
 6 files changed, 136 insertions(+), 60 deletions(-)
 create mode 100644 drivers/mtd/parsers/Kconfig
 create mode 100644 drivers/mtd/parsers/Makefile
 create mode 100644 drivers/mtd/parsers/parser_trx.c

diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index e83a279..5a2d717 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -155,6 +155,10 @@ config MTD_BCM47XX_PARTS
 	  This provides partitions parser for devices based on BCM47xx
 	  boards.
 
+menu "Partition parsers"
+source "drivers/mtd/parsers/Kconfig"
+endmenu
+
 comment "User Modules And Translation Layers"
 
 #
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index 99bb9a1..151d60df 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -13,6 +13,7 @@ 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
+obj-y				+= parsers/
 
 # 'Users' - code which presents functionality to userspace.
 obj-$(CONFIG_MTD_BLKDEVS)	+= mtd_blkdevs.o
diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c
index 845dd27..61a6f45 100644
--- a/drivers/mtd/bcm47xxpart.c
+++ b/drivers/mtd/bcm47xxpart.c
@@ -42,7 +42,6 @@
 #define ML_MAGIC2			0x26594131
 #define TRX_MAGIC			0x30524448
 #define SHSQ_MAGIC			0x71736873	/* shsq (weird ZTE H218N endianness) */
-#define UBI_EC_MAGIC			0x23494255	/* UBI# */
 
 struct trx_header {
 	uint32_t magic;
@@ -61,28 +60,6 @@ static void bcm47xxpart_add_part(struct mtd_partition *part, const char *name,
 	part->mask_flags = mask_flags;
 }
 
-static const char *bcm47xxpart_trx_data_part_name(struct mtd_info *master,
-						  size_t offset)
-{
-	uint32_t buf;
-	size_t bytes_read;
-	int err;
-
-	err  = mtd_read(master, offset, sizeof(buf), &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);
-		goto out_default;
-	}
-
-	if (buf == UBI_EC_MAGIC)
-		return "ubi";
-
-out_default:
-	return "rootfs";
-}
-
 static int bcm47xxpart_parse(struct mtd_info *master,
 			     const struct mtd_partition **pparts,
 			     struct mtd_part_parser_data *data)
@@ -190,44 +167,10 @@ static int bcm47xxpart_parse(struct mtd_info *master,
 			trx = (struct trx_header *)buf;
 
 			trx_part = curr_part;
-			bcm47xxpart_add_part(&parts[curr_part++], "firmware",
+			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++;
-			}
-
-			if (trx->offset[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.
-			 */
-			if (trx->offset[i]) {
-				const char *name;
-
-				name = bcm47xxpart_trx_data_part_name(master, offset + trx->offset[i]);
-				bcm47xxpart_add_part(&parts[curr_part++],
-						     name,
-						     offset + trx->offset[i],
-						     0);
-				i++;
-			}
-
-			last_trx_part = curr_part - 1;
+			parts[curr_part].parser = "trx";
+			curr_part++;
 
 			/*
 			 * We have whole TRX scanned, skip to the next part. Use
diff --git a/drivers/mtd/parsers/Kconfig b/drivers/mtd/parsers/Kconfig
new file mode 100644
index 0000000..3114276
--- /dev/null
+++ b/drivers/mtd/parsers/Kconfig
@@ -0,0 +1,8 @@
+config MTD_PARSER_TRX
+	tristate "Parser for TRX format partitions"
+	depends on MTD && (BCM47XX || ARCH_BCM_5301X)
+	help
+	  TRX is a firmware format used by Broadcom on their devices. It
+	  may contain up to 3/4 partitions (depending on the version).
+	  This driver will parse partitions marked as TRX ones and on
+	  success it will at least two partitions: kernel and rootfs.
diff --git a/drivers/mtd/parsers/Makefile b/drivers/mtd/parsers/Makefile
new file mode 100644
index 0000000..4d9024e
--- /dev/null
+++ b/drivers/mtd/parsers/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_MTD_PARSER_TRX)		+= parser_trx.o
diff --git a/drivers/mtd/parsers/parser_trx.c b/drivers/mtd/parsers/parser_trx.c
new file mode 100644
index 0000000..f571d3c
--- /dev/null
+++ b/drivers/mtd/parsers/parser_trx.c
@@ -0,0 +1,119 @@
+/*
+ * Parser for TRX format partitions
+ *
+ * Copyright (C) 2016 RafaÅ MiÅecki <rafal.milecki@xxxxxxxxx>
+ *
+ * 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/slab.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+
+#define TRX_PARSER_MAX_PARTS		4
+
+/* Magics */
+#define UBI_EC_MAGIC			0x23494255	/* UBI# */
+
+struct trx_header {
+	uint32_t magic;
+	uint32_t length;
+	uint32_t crc32;
+	uint16_t flags;
+	uint16_t version;
+	uint32_t offset[3];
+} __packed;
+
+static const char *parser_trx_data_part_name(struct mtd_info *master,
+						  size_t offset)
+{
+	uint32_t buf;
+	size_t bytes_read;
+	int err;
+
+	err  = mtd_read(master, offset, sizeof(buf), &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);
+		goto out_default;
+	}
+
+	if (buf == UBI_EC_MAGIC)
+		return "ubi";
+
+out_default:
+	return "rootfs";
+}
+
+static int parser_trx_parse(struct mtd_info *mtd,
+			    const struct mtd_partition **pparts,
+			    struct mtd_part_parser_data *data)
+{
+	struct mtd_partition *parts;
+	struct mtd_partition *part;
+	struct trx_header trx;
+	size_t bytes_read;
+	uint8_t curr_part = 0, i = 0;
+	int err;
+
+	parts = kzalloc(sizeof(struct mtd_partition) * TRX_PARSER_MAX_PARTS,
+			GFP_KERNEL);
+	if (!parts)
+		return -ENOMEM;
+
+	err = mtd_read(mtd, 0, sizeof(trx), &bytes_read, (uint8_t *)&trx);
+	if (err) {
+		pr_err("MTD reading error: %d\n", err);
+		return err;
+	}
+
+	/* We have LZMA loader if offset[2] points to sth */
+	if (trx.offset[2]) {
+		part = &parts[curr_part++];
+		part->name = "loader";
+		part->offset = trx.offset[i];
+		i++;
+	}
+
+	if (trx.offset[i]) {
+		part = &parts[curr_part++];
+		part->name = "linux";
+		part->offset = trx.offset[i];
+		i++;
+	}
+
+	if (trx.offset[i]) {
+		part = &parts[curr_part++];
+		part->name = parser_trx_data_part_name(mtd, trx.offset[i]);
+		part->offset = trx.offset[i];
+		i++;
+	}
+
+	/*
+	 * Assume that every partition ends at the beginning of the one it is
+	 * followed by.
+	 */
+	for (i = 0; i < curr_part; i++) {
+		u64 next_part_offset = (i < curr_part - 1) ?
+				       parts[i + 1].offset : mtd->size;
+
+		parts[i].size = next_part_offset - parts[i].offset;
+	}
+
+	*pparts = parts;
+	return i;
+};
+
+static struct mtd_part_parser mtd_parser_trx = {
+	.parse_fn = parser_trx_parse,
+	.name = "trx",
+};
+module_mtd_part_parser(mtd_parser_trx);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Parser for TRX format partitions");
-- 
1.8.4.5