kernel: use V10 of mtd patchset adding support for "compatible" string

In the commit bde5e7a632ef0 ("kernel: backport mtd implementation for
"compatible" in "partitions" subnode") patches that got accepted into
l2-mtd.git were backported to the kernels 4.9 and 4.14. Unfortunately
there was a regression report, patches were dropped and never reached
4.16.

This commit replaces these pseudo-backports with the latest version
that includes regression fix and futher changes that were requested.

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

1 files changed, 194 insertions, 0 deletions

diff --git a/target/linux/generic/pending-4.14/160-0001-mtd-partitions-add-of_match_table-parser-matching-fo.patch b/target/linux/generic/pending-4.14/160-0001-mtd-partitions-add-of_match_table-parser-matching-fo.patch
new file mode 100644
index 0000000000..3334203d8a
--- /dev/null
+++ b/target/linux/generic/pending-4.14/160-0001-mtd-partitions-add-of_match_table-parser-matching-fo.patch
@@ -0,0 +1,194 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Tue, 30 Jan 2018 11:55:16 +0100
+Subject: [PATCH V10 1/3] mtd: partitions: add of_match_table parser matching
+ for the "ofpart" type
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+In order to properly support compatibility strings as described in the
+bindings/mtd/partition.txt "ofpart" type should be treated as an
+indication for looking into OF. MTD should check "compatible" property
+and search for a matching parser rather than blindly trying the one
+supporting "fixed-partitions".
+
+It also means that existing "fixed-partitions" parser should get renamed
+to use a more meaningful name.
+
+This commit achievies that aim by introducing a new mtd_part_of_parse().
+It works by looking for a matching parser for every string in the
+"compatibility" property (starting with the most specific one).
+
+Please note that driver-specified parsers still take a precedence. It's
+assumed that driver providing a parser type has a good reason for that
+(e.g. having platform data with device-specific info). Also doing
+otherwise could break existing setups. The same applies to using default
+parsers (including "cmdlinepart") as some overwrite DT data with cmdline
+argument.
+
+Partition parsers can now provide an of_match_table to enable
+flash<-->parser matching via device tree as documented in the
+mtd/partition.txt.
+
+This support is currently limited to built-in parsers as it uses
+request_module() and friends. This should be sufficient for most cases
+though as compiling parsers as modules isn't a common choice.
+
+Signed-off-by: Brian Norris <computersforpeace@gmail.com>
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Tested-by: Peter Rosin <peda@axentia.se>
+---
+
+--- a/drivers/mtd/mtdpart.c
++++ b/drivers/mtd/mtdpart.c
+@@ -30,6 +30,7 @@
+ #include <linux/mtd/mtd.h>
+ #include <linux/mtd/partitions.h>
+ #include <linux/err.h>
++#include <linux/of.h>
+ 
+ #include "mtdcore.h"
+ 
+@@ -894,6 +895,92 @@ static int mtd_part_do_parse(struct mtd_
+ }
+ 
+ /**
++ * mtd_part_get_compatible_parser - find MTD parser by a compatible string
++ *
++ * @compat: compatible string describing partitions in a device tree
++ *
++ * MTD parsers can specify supported partitions by providing a table of
++ * compatibility strings. This function finds a parser that advertises support
++ * for a passed value of "compatible".
++ */
++static struct mtd_part_parser *mtd_part_get_compatible_parser(const char *compat)
++{
++	struct mtd_part_parser *p, *ret = NULL;
++
++	spin_lock(&part_parser_lock);
++
++	list_for_each_entry(p, &part_parsers, list) {
++		const struct of_device_id *matches;
++
++		matches = p->of_match_table;
++		if (!matches)
++			continue;
++
++		for (; matches->compatible[0]; matches++) {
++			if (!strcmp(matches->compatible, compat) &&
++			    try_module_get(p->owner)) {
++				ret = p;
++				break;
++			}
++		}
++
++		if (ret)
++			break;
++	}
++
++	spin_unlock(&part_parser_lock);
++
++	return ret;
++}
++
++static int mtd_part_of_parse(struct mtd_info *master,
++			     struct mtd_partitions *pparts)
++{
++	struct mtd_part_parser *parser;
++	struct device_node *np;
++	struct property *prop;
++	const char *compat;
++	const char *fixed = "ofpart";
++	int ret, err = 0;
++
++	np = of_get_child_by_name(mtd_get_of_node(master), "partitions");
++	of_property_for_each_string(np, "compatible", prop, compat) {
++		parser = mtd_part_get_compatible_parser(compat);
++		if (!parser)
++			continue;
++		ret = mtd_part_do_parse(parser, master, pparts, NULL);
++		if (ret > 0) {
++			of_node_put(np);
++			return ret;
++		}
++		mtd_part_parser_put(parser);
++		if (ret < 0 && !err)
++			err = ret;
++	}
++	of_node_put(np);
++
++	/*
++	 * For backward compatibility we have to try the "ofpart"
++	 * parser. It supports old DT format with partitions specified as a
++	 * direct subnodes of a flash device DT node without any compatibility
++	 * specified we could match.
++	 */
++	parser = mtd_part_parser_get(fixed);
++	if (!parser && !request_module("%s", fixed))
++		parser = mtd_part_parser_get(fixed);
++	if (parser) {
++		ret = mtd_part_do_parse(parser, master, pparts, NULL);
++		if (ret > 0)
++			return ret;
++		mtd_part_parser_put(parser);
++		if (ret < 0 && !err)
++			err = ret;
++	}
++
++	return err;
++}
++
++/**
+  * parse_mtd_partitions - parse MTD partitions
+  * @master: the master partition (describes whole MTD device)
+  * @types: names of partition parsers to try or %NULL
+@@ -925,19 +1012,30 @@ int parse_mtd_partitions(struct mtd_info
+ 		types = default_mtd_part_types;
+ 
+ 	for ( ; *types; types++) {
+-		pr_debug("%s: parsing partitions %s\n", master->name, *types);
+-		parser = mtd_part_parser_get(*types);
+-		if (!parser && !request_module("%s", *types))
++		/*
++		 * ofpart is a special type that means OF partitioning info
++		 * should be used. It requires a bit different logic so it is
++		 * handled in a separated function.
++		 */
++		if (!strcmp(*types, "ofpart")) {
++			ret = mtd_part_of_parse(master, pparts);
++		} else {
++			pr_debug("%s: parsing partitions %s\n", master->name,
++				 *types);
+ 			parser = mtd_part_parser_get(*types);
+-		pr_debug("%s: got parser %s\n", master->name,
+-			 parser ? parser->name : NULL);
+-		if (!parser)
+-			continue;
+-		ret = mtd_part_do_parse(parser, master, pparts, data);
++			if (!parser && !request_module("%s", *types))
++				parser = mtd_part_parser_get(*types);
++			pr_debug("%s: got parser %s\n", master->name,
++				parser ? parser->name : NULL);
++			if (!parser)
++				continue;
++			ret = mtd_part_do_parse(parser, master, pparts, data);
++			if (ret <= 0)
++				mtd_part_parser_put(parser);
++		}
+ 		/* Found partitions! */
+ 		if (ret > 0)
+ 			return 0;
+-		mtd_part_parser_put(parser);
+ 		/*
+ 		 * Stash the first error we see; only report it if no parser
+ 		 * succeeds
+--- a/include/linux/mtd/partitions.h
++++ b/include/linux/mtd/partitions.h
+@@ -77,6 +77,7 @@ struct mtd_part_parser {
+ 	struct list_head list;
+ 	struct module *owner;
+ 	const char *name;
++	const struct of_device_id *of_match_table;
+ 	int (*parse_fn)(struct mtd_info *, const struct mtd_partition **,
+ 			struct mtd_part_parser_data *);
+ 	void (*cleanup)(const struct mtd_partition *pparts, int nr_parts);