Merge branch 'u-boot-imx/master' into 'u-boot-arm/master'

[karo-tx-uboot.git] / doc / README.nand

diff --git a/doc/README.nand b/doc/README.nand
index 1602b5eee96da355d46539c140280e58d63bcaa2..a1a511c5339cbc8f9b6d71e1b13cf7e609fa9156 100644 (file)
--- a/doc/README.nand
+++ b/doc/README.nand
@@ -108,6 +108,9 @@ Configuration Options:
    CONFIG_CMD_NAND
       Enables NAND support and commmands.
 
+   CONFIG_CMD_NAND_TORTURE
+      Enables the torture command (see description of this command below).
+
    CONFIG_MTD_NAND_ECC_JFFS2
       Define this if you want the Error Correction Code information in
       the out-of-band data to be formatted to match the JFFS2 file system.
@@ -213,6 +216,24 @@ Miscellaneous and testing commands:
   DANGEROUS!!! Factory set bad blocks will be lost. Use only
   to remove artificial bad blocks created with the "markbad" command.
 
+  "torture offset"
+  Torture block to determine if it is still reliable.
+  Enabled by the CONFIG_CMD_NAND_TORTURE configuration option.
+  This command returns 0 if the block is still reliable, else 1.
+  If the block is detected as unreliable, it is up to the user to decide to
+  mark this block as bad.
+  The analyzed block is put through 3 erase / write cycles (or less if the block
+  is detected as unreliable earlier).
+  This command can be used in scripts, e.g. together with the markbad command to
+  automate retries and handling of possibly newly detected bad blocks if the
+  nand write command fails.
+  It can also be used manually by users having seen some NAND errors in logs to
+  search the root cause of these errors.
+  The underlying nand_torture() function is also useful for code willing to
+  automate actions following a nand->write() error. This would e.g. be required
+  in order to program or update safely firmware to NAND, especially for the UBI
+  part of such firmware.
+
 
 NAND locking command (for chips with active LOCKPRE pin)
 
@@ -228,6 +249,8 @@ NAND locking command (for chips with active LOCKPRE pin)
   "nand unlock [offset] [size]"
   unlock consecutive area (can be called multiple times for different areas)
 
+  "nand unlock.allexcept [offset] [size]"
+  unlock all except specified consecutive area
 
 I have tested the code with board containing 128MiB NAND large page chips
 and 32MiB small page chips.