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