OpenWrt – Rev 3

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From: Daniel Golle <daniel@makrotopia.org>
Subject: ubi: auto-attach mtd device named "ubi" or "data" on boot

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 drivers/mtd/ubi/build.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -1171,6 +1171,49 @@ static struct mtd_info * __init open_mtd
        return mtd;
 }
 
+/*
+ * This function tries attaching mtd partitions named either "ubi" or "data"
+ * during boot.
+ */
+static void __init ubi_auto_attach(void)
+{
+       int err;
+       struct mtd_info *mtd;
+
+       /* try attaching mtd device named "ubi" or "data" */
+       mtd = open_mtd_device("ubi");
+       if (IS_ERR(mtd))
+               mtd = open_mtd_device("data");
+
+       if (!IS_ERR(mtd)) {
+               size_t len;
+               char magic[4];
+
+               /* check for a valid ubi magic */
+               err = mtd_read(mtd, 0, 4, &len, (void *) magic);
+               if (!err && len == 4 && strncmp(magic, "UBI#", 4)) {
+                       pr_err("UBI error: no valid UBI magic found inside mtd%d\n", mtd->index);
+                       put_mtd_device(mtd);
+                       return;
+               }
+
+               /* auto-add only media types where UBI makes sense */
+               if (mtd->type == MTD_NANDFLASH ||
+                   mtd->type == MTD_NORFLASH ||
+                   mtd->type == MTD_DATAFLASH ||
+                   mtd->type == MTD_MLCNANDFLASH) {
+                       mutex_lock(&ubi_devices_mutex);
+                       pr_notice("UBI: auto-attach mtd%d\n", mtd->index);
+                       err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO, 0, 0);
+                       mutex_unlock(&ubi_devices_mutex);
+                       if (err < 0) {
+                               pr_err("UBI error: cannot attach mtd%d\n", mtd->index);
+                               put_mtd_device(mtd);
+                       }
+               }
+       }
+}
+
 static int __init ubi_init(void)
 {
        int err, i, k;
@@ -1254,6 +1297,12 @@ static int __init ubi_init(void)
                }
        }
 
+       /* auto-attach mtd devices only if built-in to the kernel and no ubi.mtd
+        * parameter was given */
+       if (IS_ENABLED(CONFIG_MTD_ROOTFS_ROOT_DEV) &&
+           !ubi_is_module() && !mtd_devs)
+               ubi_auto_attach();
+
        err = ubiblock_init();
        if (err) {
                pr_err("UBI error: block: cannot initialize, error %d\n", err);