kernel: use accepted mtd patchset adding support for "compatible" string

These patches were finally accepted and are already present in the
Linus's tree. This should be good enough to make is "backport" material.

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

1 files changed, 200 insertions, 0 deletions

diff --git a/target/linux/generic/backport-4.14/041-v4.17-0001-mtd-partitions-add-of_match_table-parser-matching-fo.patch b/target/linux/generic/backport-4.14/041-v4.17-0001-mtd-partitions-add-of_match_table-parser-matching-fo.patch
new file mode 100644
index 0000000000..bd39a2625e
--- /dev/null
+++ b/target/linux/generic/backport-4.14/041-v4.17-0001-mtd-partitions-add-of_match_table-parser-matching-fo.patch
@@ -0,0 +1,200 @@
+From 5b644aa012f67fd211138a067b9f351f30bdcc60 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Wed, 14 Mar 2018 13:10:42 +0100
+Subject: [PATCH] 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>
+Reviewed-by: Richard Weinberger <richard@nod.at>
+Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
+---
+ drivers/mtd/mtdpart.c          | 116 +++++++++++++++++++++++++++++++++++++----
+ include/linux/mtd/partitions.h |   1 +
+ 2 files changed, 108 insertions(+), 9 deletions(-)
+
+--- 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);