UBI: Wire-up fastmap

[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / mtd / ubi / Kconfig

diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig
index 271a842..36663af 100644 (file)
--- a/drivers/mtd/ubi/Kconfig
+++ b/drivers/mtd/ubi/Kconfig
@@ -56,6 +56,27 @@ config MTD_UBI_BEB_LIMIT
 
          Leave the default value if unsure.
 
+config MTD_UBI_FASTMAP
+       bool "UBI Fastmap (Experimental feature)"
+       default n
+       help
+          Important: this feature is experimental so far and the on-flash
+          format for fastmap may change in the next kernel versions
+
+          Fastmap is a mechanism which allows attaching an UBI device
+          in nearly constant time. Instead of scanning the whole MTD device it
+          only has to locate a checkpoint (called fastmap) on the device.
+          The on-flash fastmap contains all information needed to attach
+          the device. Using fastmap makes only sense on large devices where
+          attaching by scanning takes long. UBI will not automatically install
+          a fastmap on old images, but you can set the UBI module parameter
+          fm_autoconvert to 1 if you want so. Please note that fastmap-enabled
+          images are still usable with UBI implementations without
+          fastmap support. On typical flash devices the whole fastmap fits
+          into one PEB. UBI will reserve PEBs to hold two fastmaps.
+
+          If in doubt, say "N".
+
 config MTD_UBI_GLUEBI
        tristate "MTD devices emulation driver (gluebi)"
        help