target/linux/generic/backport-4.14/041-v4.16-0001-mtd-partitions-add-of_match_table-parser-matching.patch

   1 From bb2192123ec70470d6ea33f138846b175403a968 Mon Sep 17 00:00:00 2001
   2 From: Brian Norris <computersforpeace@gmail.com>
   3 Date: Thu, 4 Jan 2018 08:05:33 +0100
   4 Subject: [PATCH] mtd: partitions: add of_match_table parser matching
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Partition parsers can now provide an of_match_table to enable
  10 flash<-->parser matching via device tree as documented in the
  11 mtd/partition.txt.
  12
  13 It works by looking for a matching parser for every string in the
  14 "compatibility" property (starting with the most specific one).
  15
  16 This support is currently limited to built-in parsers as it uses
  17 request_module() and friends. This should be sufficient for most cases
  18 though as compiling parsers as modules isn't a common choice.
  19
  20 Signed-off-by: Brian Norris <computersforpeace@gmail.com>
  21 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  22 Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
  23 ---
  24  drivers/mtd/mtdpart.c          | 59 ++++++++++++++++++++++++++++++++++++++++++
  25  include/linux/mtd/partitions.h |  1 +
  26  2 files changed, 60 insertions(+)
  27
  28 --- a/drivers/mtd/mtdpart.c
  29 +++ b/drivers/mtd/mtdpart.c
  30 @@ -30,6 +30,7 @@
  31  #include <linux/mtd/mtd.h>
  32  #include <linux/mtd/partitions.h>
  33  #include <linux/err.h>
  34 +#include <linux/of.h>
  35
  36  #include "mtdcore.h"
  37
  38 @@ -894,6 +895,45 @@ static int mtd_part_do_parse(struct mtd_
  39  }
  40
  41  /**
  42 + * mtd_part_get_compatible_parser - find MTD parser by a compatible string
  43 + *
  44 + * @compat: compatible string describing partitions in a device tree
  45 + *
  46 + * MTD parsers can specify supported partitions by providing a table of
  47 + * compatibility strings. This function finds a parser that advertises support
  48 + * for a passed value of "compatible".
  49 + */
  50 +static struct mtd_part_parser *mtd_part_get_compatible_parser(const char *compat)
  51 +{
  52 +       struct mtd_part_parser *p, *ret = NULL;
  53 +
  54 +       spin_lock(&part_parser_lock);
  55 +
  56 +       list_for_each_entry(p, &part_parsers, list) {
  57 +               const struct of_device_id *matches;
  58 +
  59 +               matches = p->of_match_table;
  60 +               if (!matches)
  61 +                       continue;
  62 +
  63 +               for (; matches->compatible[0]; matches++) {
  64 +                       if (!strcmp(matches->compatible, compat) &&
  65 +                           try_module_get(p->owner)) {
  66 +                               ret = p;
  67 +                               break;
  68 +                       }
  69 +               }
  70 +
  71 +               if (ret)
  72 +                       break;
  73 +       }
  74 +
  75 +       spin_unlock(&part_parser_lock);
  76 +
  77 +       return ret;
  78 +}
  79 +
  80 +/**
  81   * parse_mtd_partitions - parse MTD partitions
  82   * @master: the master partition (describes whole MTD device)
  83   * @types: names of partition parsers to try or %NULL
  84 @@ -919,8 +959,27 @@ int parse_mtd_partitions(struct mtd_info
  85                          struct mtd_part_parser_data *data)
  86  {
  87         struct mtd_part_parser *parser;
  88 +       struct device_node *np;
  89 +       struct property *prop;
  90 +       const char *compat;
  91         int ret, err = 0;
  92
  93 +       np = of_get_child_by_name(mtd_get_of_node(master), "partitions");
  94 +       of_property_for_each_string(np, "compatible", prop, compat) {
  95 +               parser = mtd_part_get_compatible_parser(compat);
  96 +               if (!parser)
  97 +                       continue;
  98 +               ret = mtd_part_do_parse(parser, master, pparts, data);
  99 +               if (ret > 0) {
 100 +                       of_node_put(np);
 101 +                       return 0;
 102 +               }
 103 +               mtd_part_parser_put(parser);
 104 +               if (ret < 0 && !err)
 105 +                       err = ret;
 106 +       }
 107 +       of_node_put(np);
 108 +
 109         if (!types)
 110                 types = default_mtd_part_types;
 111
 112 --- a/include/linux/mtd/partitions.h
 113 +++ b/include/linux/mtd/partitions.h
 114 @@ -77,6 +77,7 @@ struct mtd_part_parser {
 115         struct list_head list;
 116         struct module *owner;
 117         const char *name;
 118 +       const struct of_device_id *of_match_table;
 119         int (*parse_fn)(struct mtd_info *, const struct mtd_partition **,
 120                         struct mtd_part_parser_data *);
 121         void (*cleanup)(const struct mtd_partition *pparts, int nr_parts);