openwrtv4/target/linux/generic/backport-4.14/046-v4.19-mtd-partitions-use-DT-info-for-parsing-partitions-wi.patch
Rafał Miłecki 2a598bbaa3 kernel: backport mtd support for subpartitions in DT
This is a new & warm feature that allows nesting partiitons in DT and
mixing their types (e.g. static vs. dynamic). It's very useful for
boards that have most partitions static but some of them require extra
parsing (e.g. a "firmware" partition).

It's required to successfully backport support for new devices using
that new syntax in their DT files.

Since brcm63xx has a custom alternative patch the upstream one is being
reverted for it. The plan is to make brcm63xx use the upstream
implementation.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
2018-07-27 22:16:24 +02:00

102 lines
3.5 KiB
Diff

From 76a832254ab05502c9394cc51ded6f0abe0e0bee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Fri, 13 Jul 2018 16:32:21 +0200
Subject: [PATCH] mtd: partitions: use DT info for parsing partitions with
"compatible" prop
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
So far only flash devices could be described in DT regarding partitions
parsing. That could be done with "partitions" subnode and a proper
"compatible" string.
Some devices may use hierarchical (multi-level) layouts and may mix used
layouts (fixed and dynamic). Describing that in DT is done by specifying
"compatible" for DT-represented partition plus optionally more
properties and/or subnodes.
To support such layouts each DT partition has to be checked for
additional description.
Please note this implementation will work in parallel with support for
partition type specified for non-DT setups. That already works since
commit 1a0915be1926 ("mtd: partitions: add support for partition
parsers").
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
---
drivers/mtd/mtdpart.c | 33 +++++++++++++--------------------
1 file changed, 13 insertions(+), 20 deletions(-)
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -370,22 +370,6 @@ 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)
-{
- return parse_mtd_partitions(&slave->mtd, types, NULL);
-}
-
static struct mtd_part *allocate_partition(struct mtd_info *parent,
const struct mtd_partition *part, int partno,
uint64_t cur_offset)
@@ -783,8 +767,8 @@ 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);
+ /* Look for subpartitions */
+ parse_mtd_partitions(&slave->mtd, parts[i].types, NULL);
cur_offset = slave->offset + slave->mtd.size;
}
@@ -860,6 +844,12 @@ static const char * const default_mtd_pa
NULL
};
+/* Check DT only when looking for subpartitions. */
+static const char * const default_subpartition_types[] = {
+ "ofpart",
+ NULL
+};
+
static int mtd_part_do_parse(struct mtd_part_parser *parser,
struct mtd_info *master,
struct mtd_partitions *pparts,
@@ -930,7 +920,9 @@ static int mtd_part_of_parse(struct mtd_
const char *fixed = "fixed-partitions";
int ret, err = 0;
- np = of_get_child_by_name(mtd_get_of_node(master), "partitions");
+ np = mtd_get_of_node(master);
+ if (!mtd_is_partition(master))
+ np = of_get_child_by_name(np, "partitions");
of_property_for_each_string(np, "compatible", prop, compat) {
parser = mtd_part_get_compatible_parser(compat);
if (!parser)
@@ -993,7 +985,8 @@ int parse_mtd_partitions(struct mtd_info
int ret, err = 0;
if (!types)
- types = default_mtd_part_types;
+ types = mtd_is_partition(master) ? default_subpartition_types :
+ default_mtd_part_types;
for ( ; *types; types++) {
/*