ac9bcefa3b
In the commit bde5e7a632 ("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>
194 lines
6 KiB
Diff
194 lines
6 KiB
Diff
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Tue, 30 Jan 2018 11:55:16 +0100
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Subject: [PATCH V10 1/3] mtd: partitions: add of_match_table parser matching
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for the "ofpart" type
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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In order to properly support compatibility strings as described in the
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bindings/mtd/partition.txt "ofpart" type should be treated as an
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indication for looking into OF. MTD should check "compatible" property
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and search for a matching parser rather than blindly trying the one
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supporting "fixed-partitions".
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It also means that existing "fixed-partitions" parser should get renamed
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to use a more meaningful name.
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This commit achievies that aim by introducing a new mtd_part_of_parse().
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It works by looking for a matching parser for every string in the
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"compatibility" property (starting with the most specific one).
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Please note that driver-specified parsers still take a precedence. It's
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assumed that driver providing a parser type has a good reason for that
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(e.g. having platform data with device-specific info). Also doing
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otherwise could break existing setups. The same applies to using default
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parsers (including "cmdlinepart") as some overwrite DT data with cmdline
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argument.
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Partition parsers can now provide an of_match_table to enable
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flash<-->parser matching via device tree as documented in the
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mtd/partition.txt.
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This support is currently limited to built-in parsers as it uses
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request_module() and friends. This should be sufficient for most cases
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though as compiling parsers as modules isn't a common choice.
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Signed-off-by: Brian Norris <computersforpeace@gmail.com>
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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Tested-by: Peter Rosin <peda@axentia.se>
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---
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--- a/drivers/mtd/mtdpart.c
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+++ b/drivers/mtd/mtdpart.c
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@@ -30,6 +30,7 @@
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/partitions.h>
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#include <linux/err.h>
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+#include <linux/of.h>
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#include "mtdcore.h"
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@@ -886,6 +887,92 @@ static int mtd_part_do_parse(struct mtd_
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}
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/**
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+ * mtd_part_get_compatible_parser - find MTD parser by a compatible string
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+ *
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+ * @compat: compatible string describing partitions in a device tree
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+ *
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+ * MTD parsers can specify supported partitions by providing a table of
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+ * compatibility strings. This function finds a parser that advertises support
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+ * for a passed value of "compatible".
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+ */
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+static struct mtd_part_parser *mtd_part_get_compatible_parser(const char *compat)
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+{
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+ struct mtd_part_parser *p, *ret = NULL;
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+
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+ spin_lock(&part_parser_lock);
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+
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+ list_for_each_entry(p, &part_parsers, list) {
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+ const struct of_device_id *matches;
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+
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+ matches = p->of_match_table;
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+ if (!matches)
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+ continue;
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+
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+ for (; matches->compatible[0]; matches++) {
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+ if (!strcmp(matches->compatible, compat) &&
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+ try_module_get(p->owner)) {
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+ ret = p;
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+ break;
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+ }
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+ }
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+
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+ if (ret)
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+ break;
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+ }
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+
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+ spin_unlock(&part_parser_lock);
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+
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+ return ret;
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+}
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+
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+static int mtd_part_of_parse(struct mtd_info *master,
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+ struct mtd_partitions *pparts)
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+{
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+ struct mtd_part_parser *parser;
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+ struct device_node *np;
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+ struct property *prop;
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+ const char *compat;
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+ const char *fixed = "ofpart";
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+ int ret, err = 0;
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+
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+ np = of_get_child_by_name(mtd_get_of_node(master), "partitions");
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+ of_property_for_each_string(np, "compatible", prop, compat) {
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+ parser = mtd_part_get_compatible_parser(compat);
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+ if (!parser)
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+ continue;
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+ ret = mtd_part_do_parse(parser, master, pparts, NULL);
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+ if (ret > 0) {
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+ of_node_put(np);
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+ return ret;
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+ }
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+ mtd_part_parser_put(parser);
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+ if (ret < 0 && !err)
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+ err = ret;
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+ }
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+ of_node_put(np);
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+
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+ /*
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+ * For backward compatibility we have to try the "ofpart"
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+ * parser. It supports old DT format with partitions specified as a
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+ * direct subnodes of a flash device DT node without any compatibility
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+ * specified we could match.
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+ */
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+ parser = mtd_part_parser_get(fixed);
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+ if (!parser && !request_module("%s", fixed))
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+ parser = mtd_part_parser_get(fixed);
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+ if (parser) {
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+ ret = mtd_part_do_parse(parser, master, pparts, NULL);
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+ if (ret > 0)
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+ return ret;
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+ mtd_part_parser_put(parser);
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+ if (ret < 0 && !err)
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+ err = ret;
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+ }
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+
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+ return err;
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+}
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+
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+/**
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* parse_mtd_partitions - parse MTD partitions
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* @master: the master partition (describes whole MTD device)
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* @types: names of partition parsers to try or %NULL
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@@ -917,19 +1004,30 @@ int parse_mtd_partitions(struct mtd_info
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types = default_mtd_part_types;
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for ( ; *types; types++) {
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- pr_debug("%s: parsing partitions %s\n", master->name, *types);
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- parser = mtd_part_parser_get(*types);
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- if (!parser && !request_module("%s", *types))
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+ /*
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+ * ofpart is a special type that means OF partitioning info
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+ * should be used. It requires a bit different logic so it is
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+ * handled in a separated function.
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+ */
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+ if (!strcmp(*types, "ofpart")) {
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+ ret = mtd_part_of_parse(master, pparts);
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+ } else {
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+ pr_debug("%s: parsing partitions %s\n", master->name,
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+ *types);
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parser = mtd_part_parser_get(*types);
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- pr_debug("%s: got parser %s\n", master->name,
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- parser ? parser->name : NULL);
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- if (!parser)
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- continue;
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- ret = mtd_part_do_parse(parser, master, pparts, data);
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+ if (!parser && !request_module("%s", *types))
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+ parser = mtd_part_parser_get(*types);
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+ pr_debug("%s: got parser %s\n", master->name,
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+ parser ? parser->name : NULL);
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+ if (!parser)
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+ continue;
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+ ret = mtd_part_do_parse(parser, master, pparts, data);
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+ if (ret <= 0)
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+ mtd_part_parser_put(parser);
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+ }
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/* Found partitions! */
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if (ret > 0)
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return 0;
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- mtd_part_parser_put(parser);
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/*
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* Stash the first error we see; only report it if no parser
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* succeeds
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--- a/include/linux/mtd/partitions.h
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+++ b/include/linux/mtd/partitions.h
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@@ -77,6 +77,7 @@ struct mtd_part_parser {
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struct list_head list;
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struct module *owner;
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const char *name;
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+ const struct of_device_id *of_match_table;
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int (*parse_fn)(struct mtd_info *, const struct mtd_partition **,
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struct mtd_part_parser_data *);
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void (*cleanup)(const struct mtd_partition *pparts, int nr_parts);
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