doc/README.nand - platform/external/u-boot - Gitiles

 NAND FLASH commands and notes

 # (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:

    nand bad
       Print a list of all of the bad blocks in the current device.

    nand device
       Print information about the current NAND device.

    nand device num
       Make device `num' the current device and print information about it.

    nand erase off size
    nand erase clean [off size]
       Erase `size' bytes starting at offset `off'.  Only complete erase
       blocks can be erased.

       If `clean' is specified, a JFFS2-style clean marker is written to
       each block after it is erased. If `clean' is specified without an
       offset or size, the entire flash is erased.

       This command will not erase blocks that are marked bad. There is
       a debug option in cmd_nand.c to allow bad blocks to be erased.
       Please read the warning there before using it, as blocks marked
       bad by the manufacturer must _NEVER_ be erased.

    nand info
       Print information about all of the NAND devices found.

    nand read addr ofs size
       Read `size' bytes from `ofs' in NAND flash to `addr'. If a page
       cannot be read because it is marked bad or an uncorrectable data
       error is found the command stops with an error.

    nand read.jffs2 addr ofs size
       Like `read', but the data for blocks that are marked bad is read as
       0xff. This gives a readable JFFS2 image that can be processed by
       the JFFS2 commands such as ls and fsload.

    nand read.oob addr ofs size
       Read `size' bytes from the out-of-band data area corresponding to
       `ofs' in NAND flash to `addr'. 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 or ECC errors.

    nand write addr ofs size
       Write `size' bytes from `addr' to `ofs' in NAND flash. If a page
       cannot be written because it is marked bad or the write fails the
       command stops with an error.

    nand write.jffs2 addr ofs size
       Like `write', but blocks that are marked bad are skipped and the
       is written to the next block instead. This allows writing writing
       a JFFS2 image, as long as the image is short enough to fit even
       after skipping the bad blocks. Compact images, such as those
       produced by mkfs.jffs2 should work well, but loading an image copied
       from another flash is going to be trouble if there are any bad blocks.

    nand write.oob addr ofs 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.

 Configuration Options:

    CFG_CMD_NAND
       A good one to add to CONFIG_COMMANDS since it enables NAND support.

    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.

    CFG_MAX_NAND_DEVICE
       The maximum number of NAND devices you want to support.

 NAND Interface:

    #define NAND_WAIT_READY(nand)
       Wait until the NAND flash is ready. Typically this would be a
       loop waiting for the READY/BUSY line from the flash to indicate it
       it is ready.

    #define WRITE_NAND_COMMAND(d, adr)
       Write the command byte `d' to the flash at `adr' with the
       CLE (command latch enable) line true. If your board uses writes to
       different addresses to control CLE and ALE, you can modify `adr'
       to be the appropriate address here. If your board uses I/O registers
       to control them, it is probably better to let NAND_CTL_SETCLE()
       and company do it.

    #define WRITE_NAND_ADDRESS(d, adr)
       Write the address byte `d' to the flash at `adr' with the
       ALE (address latch enable) line true. If your board uses writes to
       different addresses to control CLE and ALE, you can modify `adr'
       to be the appropriate address here. If your board uses I/O registers
       to control them, it is probably better to let NAND_CTL_SETALE()
       and company do it.

    #define WRITE_NAND(d, adr)
       Write the data byte `d' to the flash at `adr' with the
       ALE and CLE lines false. If your board uses writes to
       different addresses to control CLE and ALE, you can modify `adr'
       to be the appropriate address here. If your board uses I/O registers
       to control them, it is probably better to let NAND_CTL_CLRALE()
       and company do it.

    #define READ_NAND(adr)
       Read a data byte from the flash at `adr' with the
       ALE and CLE lines false. If your board uses reads from
       different addresses to control CLE and ALE, you can modify `adr'
       to be the appropriate address here. If your board uses I/O registers
       to control them, it is probably better to let NAND_CTL_CLRALE()
       and company do it.

    #define NAND_DISABLE_CE(nand)
       Set CE (Chip Enable) low to enable the NAND flash.

    #define NAND_ENABLE_CE(nand)
       Set CE (Chip Enable) high to disable the NAND flash.

    #define NAND_CTL_CLRALE(nandptr)
       Set ALE (address latch enable) low. If ALE control is handled by
       WRITE_NAND_ADDRESS() this can be empty.

    #define NAND_CTL_SETALE(nandptr)
       Set ALE (address latch enable) high. If ALE control is handled by
       WRITE_NAND_ADDRESS() this can be empty.

    #define NAND_CTL_CLRCLE(nandptr)
       Set CLE (command latch enable) low. If CLE control is handled by
       WRITE_NAND_ADDRESS() this can be empty.

    #define NAND_CTL_SETCLE(nandptr)
       Set CLE (command latch enable) high. If CLE control is handled by
       WRITE_NAND_ADDRESS() this can be empty.

 More Definitions:

    These definitions are needed in the board configuration for now, but
    may really belong in a header file.
    TODO: Figure which ones are truly configuration settings and rename
          them to CFG_NAND_... and move the rest somewhere appropriate.

    #define SECTORSIZE 512
    #define ADDR_COLUMN 1
    #define ADDR_PAGE 2
    #define ADDR_COLUMN_PAGE 3
    #define NAND_ChipID_UNKNOWN 0x00
    #define NAND_MAX_FLOORS 1
    #define NAND_MAX_CHIPS 1
	NAND FLASH commands and notes

	# (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:

	nand bad
	Print a list of all of the bad blocks in the current device.

	nand device
	Print information about the current NAND device.

	nand device num
	Make device `num' the current device and print information about it.

	nand erase off size
	nand erase clean [off size]
	Erase `size' bytes starting at offset `off'. Only complete erase
	blocks can be erased.

	If `clean' is specified, a JFFS2-style clean marker is written to
	each block after it is erased. If `clean' is specified without an
	offset or size, the entire flash is erased.

	This command will not erase blocks that are marked bad. There is
	a debug option in cmd_nand.c to allow bad blocks to be erased.
	Please read the warning there before using it, as blocks marked
	bad by the manufacturer must _NEVER_ be erased.

	nand info
	Print information about all of the NAND devices found.

	nand read addr ofs size
	Read `size' bytes from `ofs' in NAND flash to `addr'. If a page
	cannot be read because it is marked bad or an uncorrectable data
	error is found the command stops with an error.

	nand read.jffs2 addr ofs size
	Like `read', but the data for blocks that are marked bad is read as
	0xff. This gives a readable JFFS2 image that can be processed by
	the JFFS2 commands such as ls and fsload.

	nand read.oob addr ofs size
	Read `size' bytes from the out-of-band data area corresponding to
	`ofs' in NAND flash to `addr'. 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 or ECC errors.

	nand write addr ofs size
	Write `size' bytes from `addr' to `ofs' in NAND flash. If a page
	cannot be written because it is marked bad or the write fails the
	command stops with an error.

	nand write.jffs2 addr ofs size
	Like `write', but blocks that are marked bad are skipped and the
	is written to the next block instead. This allows writing writing
	a JFFS2 image, as long as the image is short enough to fit even
	after skipping the bad blocks. Compact images, such as those
	produced by mkfs.jffs2 should work well, but loading an image copied
	from another flash is going to be trouble if there are any bad blocks.

	nand write.oob addr ofs 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.

	Configuration Options:

	CFG_CMD_NAND
	A good one to add to CONFIG_COMMANDS since it enables NAND support.

	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.

	CFG_MAX_NAND_DEVICE
	The maximum number of NAND devices you want to support.

	NAND Interface:

	#define NAND_WAIT_READY(nand)
	Wait until the NAND flash is ready. Typically this would be a
	loop waiting for the READY/BUSY line from the flash to indicate it
	it is ready.

	#define WRITE_NAND_COMMAND(d, adr)
	Write the command byte `d' to the flash at `adr' with the
	CLE (command latch enable) line true. If your board uses writes to
	different addresses to control CLE and ALE, you can modify `adr'
	to be the appropriate address here. If your board uses I/O registers
	to control them, it is probably better to let NAND_CTL_SETCLE()
	and company do it.

	#define WRITE_NAND_ADDRESS(d, adr)
	Write the address byte `d' to the flash at `adr' with the
	ALE (address latch enable) line true. If your board uses writes to
	different addresses to control CLE and ALE, you can modify `adr'
	to be the appropriate address here. If your board uses I/O registers
	to control them, it is probably better to let NAND_CTL_SETALE()
	and company do it.

	#define WRITE_NAND(d, adr)
	Write the data byte `d' to the flash at `adr' with the
	ALE and CLE lines false. If your board uses writes to
	different addresses to control CLE and ALE, you can modify `adr'
	to be the appropriate address here. If your board uses I/O registers
	to control them, it is probably better to let NAND_CTL_CLRALE()
	and company do it.

	#define READ_NAND(adr)
	Read a data byte from the flash at `adr' with the
	ALE and CLE lines false. If your board uses reads from
	different addresses to control CLE and ALE, you can modify `adr'
	to be the appropriate address here. If your board uses I/O registers
	to control them, it is probably better to let NAND_CTL_CLRALE()
	and company do it.

	#define NAND_DISABLE_CE(nand)
	Set CE (Chip Enable) low to enable the NAND flash.

	#define NAND_ENABLE_CE(nand)
	Set CE (Chip Enable) high to disable the NAND flash.

	#define NAND_CTL_CLRALE(nandptr)
	Set ALE (address latch enable) low. If ALE control is handled by
	WRITE_NAND_ADDRESS() this can be empty.

	#define NAND_CTL_SETALE(nandptr)
	Set ALE (address latch enable) high. If ALE control is handled by
	WRITE_NAND_ADDRESS() this can be empty.

	#define NAND_CTL_CLRCLE(nandptr)
	Set CLE (command latch enable) low. If CLE control is handled by
	WRITE_NAND_ADDRESS() this can be empty.

	#define NAND_CTL_SETCLE(nandptr)
	Set CLE (command latch enable) high. If CLE control is handled by
	WRITE_NAND_ADDRESS() this can be empty.

	More Definitions:

	These definitions are needed in the board configuration for now, but
	may really belong in a header file.
	TODO: Figure which ones are truly configuration settings and rename
	them to CFG_NAND_... and move the rest somewhere appropriate.

	#define SECTORSIZE 512
	#define ADDR_COLUMN 1
	#define ADDR_PAGE 2
	#define ADDR_COLUMN_PAGE 3
	#define NAND_ChipID_UNKNOWN 0x00
	#define NAND_MAX_FLOORS 1
	#define NAND_MAX_CHIPS 1