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   1 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   2 Subject: [PATCH 2/2] mtd: bcm47xxpart: support layouts with multiple TRX
   3  partitions
   4 MIME-Version: 1.0
   5 Content-Type: text/plain; charset=UTF-8
   6 Content-Transfer-Encoding: 8bit
   7
   8 Some devices may have an extra TRX partition used as failsafe one. If
   9 we detect such partition we should set a proper name for it and don't
  10 parse it.
  11
  12 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  13 ---
  14  drivers/mtd/bcm47xxpart.c | 56 ++++++++++++++++++++++++++++++++++++++---------
  15  1 file changed, 46 insertions(+), 10 deletions(-)
  16
  17 --- a/drivers/mtd/bcm47xxpart.c
  18 +++ b/drivers/mtd/bcm47xxpart.c
  19 @@ -9,6 +9,7 @@
  20   *
  21   */
  22
  23 +#include <linux/bcm47xx_nvram.h>
  24  #include <linux/module.h>
  25  #include <linux/kernel.h>
  26  #include <linux/slab.h>
  27 @@ -144,6 +145,30 @@ static int bcm47xxpart_parse_trx(struct
  28         return curr_part;
  29  }
  30
  31 +/**
  32 + * bcm47xxpart_bootpartition - gets index of TRX partition used by bootloader
  33 + *
  34 + * Some devices may have more than one TRX partition. In such case one of them
  35 + * is the main one and another a failsafe one. Bootloader may fallback to the
  36 + * failsafe firmware if it detects corruption of the main image.
  37 + *
  38 + * This function provides info about currently used TRX partition. It's the one
  39 + * containing kernel started by the bootloader.
  40 + */
  41 +static int bcm47xxpart_bootpartition(void)
  42 +{
  43 +       char buf[4];
  44 +       int bootpartition;
  45 +
  46 +       /* Check CFE environment variable */
  47 +       if (bcm47xx_nvram_getenv("bootpartition", buf, sizeof(buf)) > 0) {
  48 +               if (!kstrtoint(buf, 0, &bootpartition))
  49 +                       return bootpartition;
  50 +       }
  51 +
  52 +       return 0;
  53 +}
  54 +
  55  static int bcm47xxpart_parse(struct mtd_info *master,
  56                              struct mtd_partition **pparts,
  57                              struct mtd_part_parser_data *data)
  58 @@ -154,7 +179,8 @@ static int bcm47xxpart_parse(struct mtd_
  59         size_t bytes_read;
  60         uint32_t offset;
  61         uint32_t blocksize = master->erasesize;
  62 -       int trx_part = -1;
  63 +       int trx_parts[2]; /* Array with indexes of TRX partitions */
  64 +       int trx_num = 0; /* Number of found TRX partitions */
  65         int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
  66         int err;
  67
  68 @@ -243,7 +269,11 @@ static int bcm47xxpart_parse(struct mtd_
  69                 if (buf[0x000 / 4] == TRX_MAGIC) {
  70                         struct trx_header *trx;
  71
  72 -                       trx_part = curr_part;
  73 +                       if (trx_num >= ARRAY_SIZE(trx_parts))
  74 +                               pr_warn("No enough space to store another TRX found at 0x%X\n",
  75 +                                       offset);
  76 +                       else
  77 +                               trx_parts[trx_num++] = curr_part;
  78                         bcm47xxpart_add_part(&parts[curr_part++], "firmware",
  79                                              offset, 0);
  80
  81 @@ -329,14 +359,20 @@ static int bcm47xxpart_parse(struct mtd_
  82         }
  83
  84         /* If there was TRX parse it now */
  85 -       if (trx_part >= 0) {
  86 -               int num_parts;
  87 +       for (i = 0; i < trx_num; i++) {
  88 +               struct mtd_partition *trx = &parts[trx_parts[i]];
  89
  90 -               num_parts = bcm47xxpart_parse_trx(master, &parts[trx_part],
  91 -                                                 parts + curr_part,
  92 -                                                 BCM47XXPART_MAX_PARTS - curr_part);
  93 -               if (num_parts > 0)
  94 -                       curr_part += num_parts;
  95 +               if (i == bcm47xxpart_bootpartition()) {
  96 +                       int num_parts;
  97 +
  98 +                       num_parts = bcm47xxpart_parse_trx(master, trx,
  99 +                                                         parts + curr_part,
 100 +                                                         BCM47XXPART_MAX_PARTS - curr_part);
 101 +                       if (num_parts > 0)
 102 +                               curr_part += num_parts;
 103 +               } else {
 104 +                       trx->name = "failsafe";
 105 +               }
 106         }
 107
 108         *pparts = parts;