kernel: backport upstream mtd support for partition parsers

In a log term it should replace our implementation. For now both can
coexist.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

1 files changed, 110 insertions, 0 deletions

diff --git a/target/linux/generic/patches-4.9/065-v4.13-0007-mtd-partitions-add-support-for-partition-parsers.patch b/target/linux/generic/patches-4.9/065-v4.13-0007-mtd-partitions-add-support-for-partition-parsers.patch
new file mode 100644
index 0000000..a28ee31
--- /dev/null
+++ b/target/linux/generic/patches-4.9/065-v4.13-0007-mtd-partitions-add-support-for-partition-parsers.patch
@@ -0,0 +1,110 @@
+From 1a0915be192606fee64830b9c5d70b7ed59426b6 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Wed, 21 Jun 2017 08:26:46 +0200
+Subject: [PATCH] mtd: partitions: add support for partition parsers
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Some devices have partitions that are kind of containers with extra
+subpartitions / volumes instead of e.g. a simple filesystem data. To
+support such cases we need to first create normal flash device
+partitions and then take care of these special ones.
+
+It's very common case for home routers. Depending on the vendor there
+are formats like TRX, Seama, TP-Link, WRGG & more. All of them are used
+to embed few partitions into a single one / single firmware file.
+
+Ideally all vendors would use some well documented / standardized format
+like UBI (and some probably start doing so), but there are still
+countless devices on the market using these poor vendor specific
+formats.
+
+This patch extends MTD subsystem by allowing to specify list of parsers
+that should be tried for a given partition. Supporting such poor formats
+is highly unlikely to be the top priority so these changes try to
+minimize maintenance cost to the minimum. It reuses existing code for
+these new parsers and just adds a one property and one new function.
+
+This implementation requires setting partition parsers in a flash
+parser. A proper change of bcm47xxpart will follow and in the future we
+will hopefully also find a solution for doing it with ofpart
+("fixed-partitions").
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Brian Norris <computersforpeace@gmail.com>
+---
+ drivers/mtd/mtdpart.c          | 31 +++++++++++++++++++++++++++++++
+ include/linux/mtd/partitions.h |  7 +++++++
+ 2 files changed, 38 insertions(+)
+
+--- a/drivers/mtd/mtdpart.c
++++ b/drivers/mtd/mtdpart.c
+@@ -369,6 +369,35 @@ static inline void free_partition(struct
+ 	kfree(p);
+ }
+ 
++/**
++ * mtd_parse_part - parse MTD partition looking for subpartitions
++ *
++ * @slave: part that is supposed to be a container and should be parsed
++ * @types: NULL-terminated array with names of partition parsers to try
++ *
++ * Some partitions are kind of containers with extra subpartitions (volumes).
++ * There can be various formats of such containers. This function tries to use
++ * specified parsers to analyze given partition and registers found
++ * subpartitions on success.
++ */
++static int mtd_parse_part(struct mtd_part *slave, const char *const *types)
++{
++	struct mtd_partitions parsed;
++	int err;
++
++	err = parse_mtd_partitions(&slave->mtd, types, &parsed, NULL);
++	if (err)
++		return err;
++	else if (!parsed.nr_parts)
++		return -ENOENT;
++
++	err = add_mtd_partitions(&slave->mtd, parsed.parts, parsed.nr_parts);
++
++	mtd_part_parser_cleanup(&parsed);
++
++	return err;
++}
++
+ static struct mtd_part *allocate_partition(struct mtd_info *parent,
+ 			const struct mtd_partition *part, int partno,
+ 			uint64_t cur_offset)
+@@ -758,6 +787,8 @@ int add_mtd_partitions(struct mtd_info *
+ 
+ 		add_mtd_device(&slave->mtd);
+ 		mtd_add_partition_attrs(slave);
++		if (parts[i].types)
++			mtd_parse_part(slave, parts[i].types);
+ 
+ 		cur_offset = slave->offset + slave->mtd.size;
+ 	}
+--- a/include/linux/mtd/partitions.h
++++ b/include/linux/mtd/partitions.h
+@@ -20,6 +20,12 @@
+  *
+  * For each partition, these fields are available:
+  * name: string that will be used to label the partition's MTD device.
++ * types: some partitions can be containers using specific format to describe
++ *	embedded subpartitions / volumes. E.g. many home routers use "firmware"
++ *	partition that contains at least kernel and rootfs. In such case an
++ *	extra parser is needed that will detect these dynamic partitions and
++ *	report them to the MTD subsystem. If set this property stores an array
++ *	of parser names to use when looking for subpartitions.
+  * size: the partition size; if defined as MTDPART_SIZ_FULL, the partition
+  * 	will extend to the end of the master MTD device.
+  * offset: absolute starting position within the master MTD device; if
+@@ -38,6 +44,7 @@
+ 
+ struct mtd_partition {
+ 	const char *name;		/* identifier string */
++	const char *const *types;	/* names of parsers to use if any */
+ 	uint64_t size;			/* partition size */
+ 	uint64_t offset;		/* offset within the master MTD space */
+ 	uint32_t mask_flags;		/* master MTD flags to mask out for this partition */