target/linux/generic/pending-6.6/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch

   1 From: Daniel Golle <daniel@makrotopia.org>
   2 Subject: ubi: auto-attach mtd device named "ubi" or "data" on boot
   3
   4 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
   5 ---
   6  drivers/mtd/ubi/build.c | 36 ++++++++++++++++++++++++++++++++++++
   7  1 file changed, 36 insertions(+)
   8
   9 --- a/drivers/mtd/ubi/build.c
  10 +++ b/drivers/mtd/ubi/build.c
  11 @@ -1264,6 +1264,74 @@ static struct mtd_notifier ubi_mtd_notif
  12         .remove = ubi_notify_remove,
  13  };
  14
  15 +
  16 +/*
  17 + * This function tries attaching mtd partitions named either "ubi" or "data"
  18 + * during boot.
  19 + */
  20 +static void __init ubi_auto_attach(void)
  21 +{
  22 +       int err;
  23 +       struct mtd_info *mtd;
  24 +       loff_t offset = 0;
  25 +       size_t len;
  26 +       char magic[4];
  27 +
  28 +       /* try attaching mtd device named "ubi" or "data" */
  29 +       mtd = open_mtd_device("ubi");
  30 +       if (IS_ERR(mtd))
  31 +               mtd = open_mtd_device("data");
  32 +
  33 +       if (IS_ERR(mtd))
  34 +               return;
  35 +
  36 +       /* get the first not bad block */
  37 +       if (mtd_can_have_bb(mtd))
  38 +               while (mtd_block_isbad(mtd, offset)) {
  39 +                       offset += mtd->erasesize;
  40 +
  41 +                       if (offset > mtd->size) {
  42 +                               pr_err("UBI error: Failed to find a non-bad "
  43 +                                      "block on mtd%d\n", mtd->index);
  44 +                               goto cleanup;
  45 +                       }
  46 +               }
  47 +
  48 +       /* check if the read from flash was successful */
  49 +       err = mtd_read(mtd, offset, 4, &len, (void *) magic);
  50 +       if ((err && !mtd_is_bitflip(err)) || len != 4) {
  51 +               pr_err("UBI error: unable to read from mtd%d\n", mtd->index);
  52 +               goto cleanup;
  53 +       }
  54 +
  55 +       /* check for a valid ubi magic */
  56 +       if (strncmp(magic, "UBI#", 4)) {
  57 +               pr_err("UBI error: no valid UBI magic found inside mtd%d\n", mtd->index);
  58 +               goto cleanup;
  59 +       }
  60 +
  61 +       /* don't auto-add media types where UBI doesn't makes sense */
  62 +       if (mtd->type != MTD_NANDFLASH &&
  63 +           mtd->type != MTD_NORFLASH &&
  64 +           mtd->type != MTD_DATAFLASH &&
  65 +           mtd->type != MTD_MLCNANDFLASH)
  66 +               goto cleanup;
  67 +
  68 +       mutex_lock(&ubi_devices_mutex);
  69 +       pr_notice("UBI: auto-attach mtd%d\n", mtd->index);
  70 +       err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO, 0, 0, false);
  71 +       mutex_unlock(&ubi_devices_mutex);
  72 +       if (err < 0) {
  73 +               pr_err("UBI error: cannot attach mtd%d\n", mtd->index);
  74 +               goto cleanup;
  75 +       }
  76 +
  77 +       return;
  78 +
  79 +cleanup:
  80 +       put_mtd_device(mtd);
  81 +}
  82 +
  83  static int __init ubi_init_attach(void)
  84  {
  85         int err, i, k;
  86 @@ -1314,6 +1382,12 @@ static int __init ubi_init_attach(void)
  87                 }
  88         }
  89
  90 +       /* auto-attach mtd devices only if built-in to the kernel and no ubi.mtd
  91 +        * parameter was given */
  92 +       if (IS_ENABLED(CONFIG_MTD_ROOTFS_ROOT_DEV) &&
  93 +           !ubi_is_module() && !mtd_devs)
  94 +               ubi_auto_attach();
  95 +
  96         return 0;
  97
  98  out_detach: