mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-14 08:57:58 +00:00
4b0abf9f3c
Commit3eb3e72a3f(nand/denali: Adding Denali NAND driver support) introduced some new options, and some of them were documented by commitf9860cf081(nand/denali: Document CONFIG symbols). This commit allows users to enable/disable them via Kconfig with more detailed help docs. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Cc: Chin Liang See <clsee@altera.com> Cc: Scott Wood <scottwood@freescale.com>
375 lines
14 KiB
Text
375 lines
14 KiB
Text
NAND FLASH commands and notes
|
|
|
|
See NOTE below!!!
|
|
|
|
# (C) Copyright 2003
|
|
# Dave Ellis, SIXNET, dge@sixnetio.com
|
|
#
|
|
# SPDX-License-Identifier: GPL-2.0+
|
|
|
|
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|partition size
|
|
nand erase clean [off|partition size]
|
|
Erase `size' bytes starting at offset `off'. Alternatively partition
|
|
name can be specified, in this case size will be eventually limited
|
|
to not exceed partition size (this behaviour applies also to read
|
|
and write commands). Only complete erase blocks can be erased.
|
|
|
|
If `erase' is specified without an offset or size, the entire flash
|
|
is erased. If `erase' is specified with partition but without an
|
|
size, the entire partition is erased.
|
|
|
|
If `clean' is specified, a JFFS2-style clean marker is written to
|
|
each block after it 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|partition size
|
|
Read `size' bytes from `ofs' in NAND flash to `addr'. Blocks that
|
|
are marked bad are skipped. If a page cannot be read because an
|
|
uncorrectable data error is found, the command stops with an error.
|
|
|
|
nand read.oob addr ofs|partition 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|partition size
|
|
Write `size' bytes from `addr' to `ofs' in NAND flash. Blocks that
|
|
are marked bad are skipped. If a page cannot be read because an
|
|
uncorrectable data error is found, the command stops with an error.
|
|
|
|
As JFFS2 skips blocks similarly, this allows 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.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 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_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.
|
|
|
|
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_YAFFS would be another useful choice for
|
|
someone to implement.
|
|
|
|
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
|
|
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.
|
|
|
|
|
|
CONFIG_SYS_NAND_ONFI_DETECTION
|
|
Enables detection of ONFI compliant devices during probe.
|
|
And fetching device parameters flashed on device, by parsing
|
|
ONFI parameter page.
|
|
|
|
CONFIG_BCH
|
|
Enables software based BCH ECC algorithm present in lib/bch.c
|
|
This is used by SoC platforms which do not have built-in ELM
|
|
hardware engine required for BCH ECC correction.
|
|
|
|
CONFIG_SYS_NAND_BUSWIDTH_16BIT
|
|
Indicates that NAND device has 16-bit wide data-bus. In absence of this
|
|
config, bus-width of NAND device is assumed to be either 8-bit and later
|
|
determined by reading ONFI params.
|
|
Above config is useful when NAND device's bus-width information cannot
|
|
be determined from on-chip ONFI params, like in following scenarios:
|
|
- SPL boot does not support reading of ONFI parameters. This is done to
|
|
keep SPL code foot-print small.
|
|
- In current U-Boot flow using nand_init(), driver initialization
|
|
happens in board_nand_init() which is called before any device probe
|
|
(nand_scan_ident + nand_scan_tail), thus device's ONFI parameters are
|
|
not available while configuring controller. So a static CONFIG_NAND_xx
|
|
is needed to know the device's bus-width in advance.
|
|
Some drivers using above config are:
|
|
drivers/mtd/nand/mxc_nand.c
|
|
drivers/mtd/nand/ndfc.c
|
|
drivers/mtd/nand/omap_gpmc.c
|
|
|
|
|
|
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_ECCSCHEME
|
|
On OMAP platforms, this CONFIG specifies NAND ECC scheme.
|
|
It can take following values:
|
|
OMAP_ECC_HAM1_CODE_SW
|
|
1-bit Hamming code using software lib.
|
|
(for legacy devices only)
|
|
OMAP_ECC_HAM1_CODE_HW
|
|
1-bit Hamming code using GPMC hardware.
|
|
(for legacy devices only)
|
|
OMAP_ECC_BCH4_CODE_HW_DETECTION_SW
|
|
4-bit BCH code (unsupported)
|
|
OMAP_ECC_BCH4_CODE_HW
|
|
4-bit BCH code (unsupported)
|
|
OMAP_ECC_BCH8_CODE_HW_DETECTION_SW
|
|
8-bit BCH code with
|
|
- ecc calculation using GPMC hardware engine,
|
|
- error detection using software library.
|
|
- requires CONFIG_BCH to enable software BCH library
|
|
(For legacy device which do not have ELM h/w engine)
|
|
OMAP_ECC_BCH8_CODE_HW
|
|
8-bit BCH code with
|
|
- ecc calculation using GPMC hardware engine,
|
|
- error detection using ELM hardware engine.
|
|
OMAP_ECC_BCH16_CODE_HW
|
|
16-bit BCH code with
|
|
- ecc calculation using GPMC hardware engine,
|
|
- error detection using ELM hardware engine.
|
|
|
|
How to select ECC scheme on OMAP and AMxx platforms ?
|
|
-----------------------------------------------------
|
|
Though higher ECC schemes have more capability to detect and correct
|
|
bit-flips, but still selection of ECC scheme is dependent on following
|
|
- hardware engines present in SoC.
|
|
Some legacy OMAP SoC do not have ELM h/w engine thus such
|
|
SoC cannot support BCHx_HW ECC schemes.
|
|
- size of OOB/Spare region
|
|
With higher ECC schemes, more OOB/Spare area is required to
|
|
store ECC. So choice of ECC scheme is limited by NAND oobsize.
|
|
|
|
In general following expression can help:
|
|
NAND_OOBSIZE >= 2 + (NAND_PAGESIZE / 512) * ECC_BYTES
|
|
where
|
|
NAND_OOBSIZE = number of bytes available in
|
|
OOB/spare area per NAND page.
|
|
NAND_PAGESIZE = bytes in main-area of NAND page.
|
|
ECC_BYTES = number of ECC bytes generated to
|
|
protect 512 bytes of data, which is:
|
|
3 for HAM1_xx ecc schemes
|
|
7 for BCH4_xx ecc schemes
|
|
14 for BCH8_xx ecc schemes
|
|
26 for BCH16_xx ecc schemes
|
|
|
|
example to check for BCH16 on 2K page NAND
|
|
NAND_PAGESIZE = 2048
|
|
NAND_OOBSIZE = 64
|
|
2 + (2048 / 512) * 26 = 106 > NAND_OOBSIZE
|
|
Thus BCH16 cannot be supported on 2K page NAND.
|
|
|
|
However, for 4K pagesize NAND
|
|
NAND_PAGESIZE = 4096
|
|
NAND_OOBSIZE = 64
|
|
ECC_BYTES = 26
|
|
2 + (4096 / 512) * 26 = 210 < NAND_OOBSIZE
|
|
Thus BCH16 can be supported on 4K page NAND.
|
|
|
|
|
|
NOTE:
|
|
=====
|
|
|
|
The current NAND implementation is based on what is in recent
|
|
Linux kernels. The old legacy implementation has been removed.
|
|
|
|
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.
|
|
|
|
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
|
|
the current NAND system but has not yet been adapted to the u-boot
|
|
environment.
|
|
|
|
Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006
|
|
|
|
JFFS2 related commands:
|
|
|
|
implement "nand erase clean" and old "nand erase"
|
|
using both the new code which is able to skip bad blocks
|
|
"nand erase clean" additionally writes JFFS2-cleanmarkers in the oob.
|
|
|
|
Miscellaneous and testing commands:
|
|
"markbad [offset]"
|
|
create an artificial bad block (for testing bad block handling)
|
|
|
|
"scrub [offset length]"
|
|
like "erase" but don't skip bad block. Instead erase them.
|
|
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 lock"
|
|
set NAND chip to lock state (all pages locked)
|
|
|
|
"nand lock tight"
|
|
set NAND chip to lock tight state (software can't change locking anymore)
|
|
|
|
"nand lock status"
|
|
displays current locking status of all pages
|
|
|
|
"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.
|