From: Brian Norris <computersforpeace@xxxxxxxxx>
Partition parsers can now provide an of_match_table to enable
flash<-->parser matching via device tree.
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@xxxxxxxxx>
Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---
This is based on Brian's patches:
[RFC PATCH 4/7] mtd: add of_match_mtd_parser() and of_mtd_match_mtd_parser() helpers
[RFC PATCH 6/7] RFC: mtd: partitions: enable of_match_table matching
V1: Put helpers in mtdpart.c instead of drivers/of/of_mtd.c
Merge helpers into a single of_mtd_match_mtd_parser
V3: Add a simple comment to note we will need the best match in the future
V4: Rework new functions to pick parser with the best match
Move new code in parse_mtd_partitions up so it has precedence over flash
driver defaults and MTD defaults
---
drivers/mtd/mtdpart.c | 65 ++++++++++++++++++++++++++++++++++++++++++
include/linux/mtd/partitions.h | 1 +
2 files changed, 66 insertions(+)
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 2ad9493703f9..239d5e6e62ed 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"
@@ -885,6 +886,60 @@ static int mtd_part_do_parse(struct mtd_part_parser *parser,
return ret;
}
+static int of_mtd_match_mtd_parser(struct mtd_info *mtd,
+ struct mtd_part_parser *parser)
+{
+ const struct of_device_id *matches;
+ struct device_node *np;
+ int score = 0;
+
+ matches = parser->of_match_table;
+ if (!matches)
+ return false;
+
+ np = mtd_get_of_node(mtd);
+ np = of_get_child_by_name(np, "partitions");
+ if (!np)
+ return false;
+
+ for (; matches->name[0] || matches->type[0] || matches->compatible[0];
+ matches++) {
+ if (!matches->compatible[0])
+ continue;
+ score = max(score,
+ of_device_is_compatible(np, matches->compatible));
+ }
+
+ of_node_put(np);
+
+ return score;
+}
+
+static struct mtd_part_parser *mtd_part_get_parser_by_of(struct mtd_info *mtd)
+{
+ struct mtd_part_parser *p, *ret = NULL;
+ struct mtd_part_parser *best_parser = NULL;
+ int best_score = 0;
+
+ spin_lock(&part_parser_lock);
+
+ list_for_each_entry(p, &part_parsers, list) {
+ int score = of_mtd_match_mtd_parser(mtd, p);
+
+ if (score > best_score) {
+ best_score = score;
+ best_parser = p;
+ }
+ }
+
+ if (best_parser && try_module_get(best_parser->owner))
+ ret = best_parser;
+
+ spin_unlock(&part_parser_lock);
+
+ return ret;
+}
+
/**
* parse_mtd_partitions - parse MTD partitions
* @master: the master partition (describes whole MTD device)
@@ -913,6 +968,16 @@ int parse_mtd_partitions(struct mtd_info *master, const char *const *types,
struct mtd_part_parser *parser;
int ret, err = 0;
+ parser = mtd_part_get_parser_by_of(master);
+ if (parser) {
+ ret = mtd_part_do_parse(parser, master, pparts, data);
+ if (ret > 0)
+ return 0;
+ mtd_part_parser_put(parser);
+ if (ret < 0)
+ err = ret;
+ }
+
if (!types)
types = default_mtd_part_types;
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);
--
2.11.0
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