target/linux/generic/pending-4.4/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch

   1 From 8a52e4100d7c3a4a1dfddfa02b8864a9b0068c13 Mon Sep 17 00:00:00 2001
   2 From: Daniel Golle <daniel@makrotopia.org>
   3 Date: Sat, 17 May 2014 03:36:18 +0200
   4 Subject: [PATCH 1/5] ubi: auto-attach mtd device named "ubi" or "data" on boot
   5 To: openwrt-devel@lists.openwrt.org
   6
   7 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
   8 ---
   9  drivers/mtd/ubi/build.c | 36 ++++++++++++++++++++++++++++++++++++
  10  1 file changed, 36 insertions(+)
  11
  12 --- a/drivers/mtd/ubi/build.c
  13 +++ b/drivers/mtd/ubi/build.c
  14 @@ -1203,6 +1203,49 @@ static struct mtd_info * __init open_mtd
  15         return mtd;
  16  }
  17
  18 +/*
  19 + * This function tries attaching mtd partitions named either "ubi" or "data"
  20 + * during boot.
  21 + */
  22 +static void __init ubi_auto_attach(void)
  23 +{
  24 +       int err;
  25 +       struct mtd_info *mtd;
  26 +
  27 +       /* try attaching mtd device named "ubi" or "data" */
  28 +       mtd = open_mtd_device("ubi");
  29 +       if (IS_ERR(mtd))
  30 +               mtd = open_mtd_device("data");
  31 +
  32 +       if (!IS_ERR(mtd)) {
  33 +               size_t len;
  34 +               char magic[4];
  35 +
  36 +               /* check for a valid ubi magic */
  37 +               err = mtd_read(mtd, 0, 4, &len, (void *) magic);
  38 +               if (!err && len == 4 && strncmp(magic, "UBI#", 4)) {
  39 +                       pr_err("UBI error: no valid UBI magic found inside mtd%d\n", mtd->index);
  40 +                       put_mtd_device(mtd);
  41 +                       return;
  42 +               }
  43 +
  44 +               /* auto-add only media types where UBI makes sense */
  45 +               if (mtd->type == MTD_NANDFLASH ||
  46 +                   mtd->type == MTD_NORFLASH ||
  47 +                   mtd->type == MTD_DATAFLASH ||
  48 +                   mtd->type == MTD_MLCNANDFLASH) {
  49 +                       mutex_lock(&ubi_devices_mutex);
  50 +                       pr_notice("UBI: auto-attach mtd%d\n", mtd->index);
  51 +                       err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO, 0, 0);
  52 +                       mutex_unlock(&ubi_devices_mutex);
  53 +                       if (err < 0) {
  54 +                               pr_err("UBI error: cannot attach mtd%d\n", mtd->index);
  55 +                               put_mtd_device(mtd);
  56 +                       }
  57 +               }
  58 +       }
  59 +}
  60 +
  61  static int __init ubi_init(void)
  62  {
  63         int err, i, k;
  64 @@ -1286,6 +1329,12 @@ static int __init ubi_init(void)
  65                 }
  66         }
  67
  68 +       /* auto-attach mtd devices only if built-in to the kernel and no ubi.mtd
  69 +        * parameter was given */
  70 +       if (config_enabled(CONFIG_MTD_ROOTFS_ROOT_DEV) &&
  71 +           !ubi_is_module() && !mtd_devs)
  72 +               ubi_auto_attach();
  73 +
  74         err = ubiblock_init();
  75         if (err) {
  76                 pr_err("UBI error: block: cannot initialize, error %d", err);