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- 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"
-
- @@ -886,6 +887,92 @@ 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
- @@ -917,19 +1004,30 @@ 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);
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