+# SPDX-License-Identifier: GPL-2.0+
NAND FLASH commands and notes
See NOTE below!!!
# (C) Copyright 2003
# Dave Ellis, SIXNET, dge@sixnetio.com
#
-# See file CREDITS for list of people who contributed to this
-# project.
-#
-# This program is free software; you can redistribute it and/or
-# modify it under the terms of the GNU General Public License as
-# published by the Free Software Foundation; either version 2 of
-# the License, or (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
-# MA 02111-1307 USA
Commands:
Configuration Options:
+ CONFIG_SYS_NAND_U_BOOT_OFFS
+ NAND Offset from where SPL will read u-boot image. This is the starting
+ address of u-boot MTD partition in NAND.
+
CONFIG_CMD_NAND
- Enables NAND support and commmands.
+ Enables NAND support and commands.
- 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_YAFFS would be another useful choice for
- someone to implement.
+ CONFIG_CMD_NAND_TORTURE
+ Enables the torture command (see description of this command below).
CONFIG_SYS_MAX_NAND_DEVICE
The maximum number of NAND devices you want to support.
+ CONFIG_SYS_NAND_MAX_ECCPOS
+ If specified, overrides the maximum number of ECC bytes
+ supported. Useful for reducing image size, especially with SPL.
+ This must be at least 48 if nand_base.c is used.
+
+ CONFIG_SYS_NAND_MAX_OOBFREE
+ If specified, overrides the maximum number of free OOB regions
+ supported. Useful for reducing image size, especially with SPL.
+ This must be at least 2 if nand_base.c is used.
+
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
+ Traditionally, glue code in drivers/mtd/nand/raw/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.
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
+ If a board defines CONFIG_SYS_NAND_SELF_INIT, drivers/mtd/nand/raw/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
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;
+ mtd = nand_to_mtd(&chip);
/*
* Fill in appropriate values if this driver uses these fields,
if (nand_scan_tail(mtd))
error out
- if (nand_register(devnum))
+ /*
+ * devnum is the device number to be used in nand commands
+ * and in mtd->name. Must be less than CONFIG_SYS_MAX_NAND_DEVICE.
+ */
+ if (nand_register(devnum, mtd))
error out
In addition to providing more flexibility to the driver, it reduces
Please convert your driver even if you don't need the extra
flexibility, so that one day we can eliminate the old mechanism.
-NOTE:
-=====
-The current NAND implementation is based on what is in recent
-Linux kernels. The old legacy implementation has been removed.
+Platform specific options
+=========================
+ CONFIG_NAND_OMAP_GPMC
+ Enables omap_gpmc.c driver for OMAPx and AMxxxx platforms.
+ GPMC controller is used for parallel NAND flash devices, and can
+ do ECC calculation (not ECC error detection) for HAM1, BCH4, BCH8
+ and BCH16 ECC algorithms.
+
+ CONFIG_NAND_OMAP_ELM
+ Enables omap_elm.c driver for OMAPx and AMxxxx platforms.
+ ELM controller is used for ECC error detection (not ECC calculation)
+ of BCH4, BCH8 and BCH16 ECC algorithms.
+ Some legacy platforms like OMAP3xx do not have in-built ELM h/w engine,
+ thus such SoC platforms need to depend on software library for ECC error
+ detection. However ECC calculation on such plaforms would still be
+ done by GPMC controller.
+
+ CONFIG_SPL_NAND_AM33XX_BCH
+ Enables SPL-NAND driver (am335x_spl_bch.c) which supports ELM based
+ hardware ECC correction. This is useful for platforms which have ELM
+ hardware engine and use NAND boot mode.
+ Some legacy platforms like OMAP3xx do not have in-built ELM h/w engine,
+ so those platforms should use CONFIG_SPL_NAND_SIMPLE for enabling
+ SPL-NAND driver with software ECC correction support.
+
+ CONFIG_NAND_OMAP_GPMC_PREFETCH
+ On OMAP platforms that use the GPMC controller
+ (CONFIG_NAND_OMAP_GPMC_PREFETCH), this options enables the code that
+ uses the prefetch mode to speed up read operations.
-If you have board code which used CONFIG_NAND_LEGACY, you'll need
-to convert to the current NAND interface for it to continue to work.
+NOTE:
+=====
The Disk On Chip driver is currently broken and has been for some time.
-There is a driver in drivers/mtd/nand, taken from Linux, that works with
+There is a driver in drivers/mtd/nand/raw, taken from Linux, that works with
the current NAND system but has not yet been adapted to the u-boot
environment.
DANGEROUS!!! Factory set bad blocks will be lost. Use only
to remove artificial bad blocks created with the "markbad" command.
+ "torture offset [size]"
+ 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.
+ Optionally, a second parameter size can be given to test multiple blocks with
+ one call. If size is not a multiple of the NAND's erase size, then the block
+ that contains offset + size will be tested in full. If used with size, this
+ command returns 0 if all tested blocks have been found reliable, else 1.
+
NAND locking command (for chips with active LOCKPRE pin)
projects / platform / kernel / u-boot.git / blobdiff