Merge samsung, imx, tegra into u-boot-arm/master

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

diff --git a/doc/README.nand b/doc/README.nand
index 8eedb6c4d70a1e417a0677ed487ded7f6239c961..a1a511c5339cbc8f9b6d71e1b13cf7e609fa9156 100644 (file)
--- a/doc/README.nand
+++ b/doc/README.nand
@@ -78,17 +78,39 @@ Commands:
       should work well, but loading an image copied from another flash is
       going to be trouble if there are any bad blocks.
 
       should work well, but loading an image copied from another flash is
       going to be trouble if there are any bad blocks.
 

+   nand write.trimffs addr ofs|partition size
+      Enabled by the CONFIG_CMD_NAND_TRIMFFS macro. This command will write to
+      the NAND flash in a manner identical to the 'nand write' command
+      described above -- with the additional check that all pages at the end
+      of eraseblocks which contain only 0xff data will not be written to the
+      NAND flash. This behaviour is required when flashing UBI images
+      containing UBIFS volumes as per the UBI FAQ[1].
+
+      [1] http://www.linux-mtd.infradead.org/doc/ubi.html#L_flasher_algo
+

    nand write.oob addr ofs|partition size
       Write `size' bytes from `addr' to the out-of-band data area
       corresponding to `ofs' in NAND flash. This is limited to the 16 bytes
       of data for one 512-byte page or 2 256-byte pages. There is no check
       for bad blocks.
 
    nand write.oob addr ofs|partition size
       Write `size' bytes from `addr' to the out-of-band data area
       corresponding to `ofs' in NAND flash. This is limited to the 16 bytes
       of data for one 512-byte page or 2 256-byte pages. There is no check
       for bad blocks.
 

+   nand read.raw addr ofs|partition [count]
+   nand write.raw addr ofs|partition [count]
+      Read or write one or more pages at "ofs" in NAND flash, from or to
+      "addr" in memory.  This is a raw access, so ECC is avoided and the
+      OOB area is transferred as well.  If count is absent, it is assumed
+      to be one page.  As with .yaffs2 accesses, the data is formatted as
+      a packed sequence of "data, oob, data, oob, ..." -- no alignment of
+      individual pages is maintained.
+

 Configuration Options:
 
    CONFIG_CMD_NAND
       Enables NAND support and commmands.
 
 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.
    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.


@@ -101,6 +123,68 @@ Configuration Options:
    CONFIG_SYS_NAND_MAX_CHIPS
       The maximum number of NAND chips per device to be supported.
 
    CONFIG_SYS_NAND_MAX_CHIPS
       The maximum number of NAND chips per device to be supported.
 

+   CONFIG_SYS_NAND_SELF_INIT
+      Traditionally, glue code in drivers/mtd/nand/nand.c has driven
+      the initialization process -- it provides the mtd and nand
+      structs, calls a board init function for a specific device,
+      calls nand_scan(), and registers with mtd.
+
+      This arrangement does not provide drivers with the flexibility to
+      run code between nand_scan_ident() and nand_scan_tail(), or other
+      deviations from the "normal" flow.
+
+      If a board defines CONFIG_SYS_NAND_SELF_INIT, drivers/mtd/nand/nand.c
+      will make one call to board_nand_init(), with no arguments.  That
+      function is responsible for calling a driver init function for
+      each NAND device on the board, that performs all initialization
+      tasks except setting mtd->name, and registering with the rest of
+      U-Boot.  Those last tasks are accomplished by calling  nand_register()
+      on the new mtd device.
+
+      Example of new init to be added to the end of an existing driver
+      init:
+
+       /*
+        * devnum is the device number to be used in nand commands
+        * and in mtd->name.  Must be less than
+        * CONFIG_SYS_NAND_MAX_DEVICE.
+        */
+       mtd = &nand_info[devnum];
+
+       /* chip is struct nand_chip, and is now provided by the driver. */
+       mtd->priv = &chip;
+
+       /*
+        * Fill in appropriate values if this driver uses these fields,
+        * or uses the standard read_byte/write_buf/etc. functions from
+        * nand_base.c that use these fields.
+        */
+       chip.IO_ADDR_R = ...;
+       chip.IO_ADDR_W = ...;
+
+       if (nand_scan_ident(mtd, CONFIG_SYS_MAX_NAND_CHIPS, NULL))
+               error out
+
+       /*
+        * Insert here any code you wish to run after the chip has been
+        * identified, but before any other I/O is done.
+        */
+
+       if (nand_scan_tail(mtd))
+               error out
+
+       if (nand_register(devnum))
+               error out
+
+      In addition to providing more flexibility to the driver, it reduces
+      the difference between a U-Boot driver and its Linux counterpart.
+      nand_init() is now reduced to calling board_nand_init() once, and
+      printing a size summary.  This should also make it easier to
+      transition to delayed NAND initialization.
+
+      Please convert your driver even if you don't need the extra
+      flexibility, so that one day we can eliminate the old mechanism.
+

 NOTE:
 =====
 
 NOTE:
 =====
 


@@ -132,6 +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.
 
   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)
 
 
 NAND locking command (for chips with active LOCKPRE pin)
 


@@ -147,6 +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 [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.
 
 I have tested the code with board containing 128MiB NAND large page chips
 and 32MiB small page chips.