Re: [PATCH V7 1/2] mtd: partitions: add of_match_table parser matching

Boris Brezillon
2018-01-11T09:05:49Z

On Thu, 4 Jan 2018 08:05:33 +0100
Rafał Miłecki <zajec5@gmail.com> wrote:

> From: Brian Norris <computersforpeace@gmail.com>
>
> Partition parsers can now provide an of_match_table to enable
> flash<-->parser matching via device tree as documented in the
> mtd/partition.txt.
>
> It works by looking for a matching parser for every string in the
> "compatibility" property (starting with the most specific one).
>
> 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.
>

Applied both patches.

Thanks,

Boris

> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
> ---
> 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
> V5: Rework matching code to start checking with the most specific string in the
> "compatibility" property.
> V6: Initialize "ret" variable in mtd_part_get_parser_by_cp to NULL
> V7: Rename function "mtd_part_get_parser_by_cp" to use "_compatible_"
> Rename "cp" variable to "compat"
> Drop unneeded if (np) check from the parse_mtd_partitions
> ---
> drivers/mtd/mtdpart.c | 59 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/mtd/partitions.h | 1 +
> 2 files changed, 60 insertions(+)
>
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index be088bccd593..76e12fb81563 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"
>
> @@ -880,6 +881,45 @@ 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;
> +}
> +
> +/**
> * parse_mtd_partitions - parse MTD partitions
> * @master: the master partition (describes whole MTD device)
> * @types: names of partition parsers to try or %NULL
> @@ -905,8 +945,27 @@ int parse_mtd_partitions(struct mtd_info *master, const char *const *types,
> struct mtd_part_parser_data *data)
> {
> struct mtd_part_parser *parser;
> + struct device_node *np;
> + struct property *prop;
> + const char *compat;
> 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, data);
> + if (ret > 0) {
> + of_node_put(np);
> + return 0;
> + }
> + mtd_part_parser_put(parser);
> + if (ret < 0 && !err)
> + err = ret;
> + }
> + of_node_put(np);
> +
> 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);