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authorRafał Miłecki <rafal@milecki.pl>2018-03-14 13:10:42 +0100
committerBoris Brezillon <boris.brezillon@bootlin.com>2018-03-27 09:10:48 +0200
commit5b644aa012f67fd211138a067b9f351f30bdcc60 (patch)
tree59dc52a7c886e68fa6786df6936d95e1a9804721
parent5741a164ff6fb5abbea8548ad0f3846bad2b9aec (diff)
mtd: partitions: add of_match_table parser matching for the "ofpart" type
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>
-rw-r--r--drivers/mtd/mtdpart.c116
-rw-r--r--include/linux/mtd/partitions.h1
2 files changed, 108 insertions, 9 deletions
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 85fea8ea3423..2b7bb834ff40 100644
--- 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"
@@ -846,6 +847,92 @@ static int mtd_part_do_parse(struct mtd_part_parser *parser,
}
/**
+ * 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
@@ -877,19 +964,30 @@ int parse_mtd_partitions(struct mtd_info *master, const char *const *types,
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
diff --git a/include/linux/mtd/partitions.h b/include/linux/mtd/partitions.h
index c4beb70dacbd..11cb0c50cd84 100644
--- 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);