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'. 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|partition 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.
+ 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
for bad blocks or ECC errors.
nand write addr ofs|partition 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|partition 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.
+ 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.oob addr ofs|partition size
Write `size' bytes from `addr' to the out-of-band data area
Configuration Options:
- CFG_CMD_NAND
- A good one to add to CONFIG_COMMANDS since it enables NAND support.
+ CONFIG_CMD_NAND
+ Enables NAND support and commmands.
CONFIG_MTD_NAND_ECC_JFFS2
Define this if you want the Error Correction Code information in
CONFIG_MTD_NAND_ECC_YAFFS would be another useful choice for
someone to implement.
- CFG_MAX_NAND_DEVICE
+ CONFIG_SYS_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
-
+ CONFIG_SYS_NAND_MAX_CHIPS
+ The maximum number of NAND chips per device to be supported.
NOTE:
=====
-We now use a complete rewrite of the NAND code based on what is in
-2.6.12 Linux kernel.
-
-The old NAND handling code has been re-factored and is now confined
-to only board-specific files and - unfortunately - to the DoC code
-(see below). A new configuration variable has been introduced:
-CFG_NAND_LEGACY, which has to be defined in the board config file if
-that board uses legacy code. If CFG_NAND_LEGACY is defined, the board
-specific config.mk file should also have "BOARDLIBS =
-drivers/nand_legacy/libnand_legacy.a". For boards using the new NAND
-approach (PPChameleon and netstar at the moment) no variable is
-necessary, but the config.mk should have "BOARDLIBS =
-drivers/nand/libnand.a".
-
-The necessary changes have been made to all affected boards, and no
-build breakage has been introduced, except for NETTA and NETTA_ISDN
-targets from MAKEALL. This is due to the fact that these two boards
-use JFFS, which has been adopted to use the new NAND, and at the same
-time use NAND in legacy mode. The breakage will disappear when the
-board-specific code is changed to the new NAND.
-
-As mentioned above, the legacy code is still used by the DoC subsystem.
-The consequence of this is that the legacy NAND can't be removed from
-the tree until the DoC is ported to use the new NAND support (or boards
-with DoC will break).
+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
using both the new code which is able to skip bad blocks
"nand erase clean" additionally writes JFFS2-cleanmarkers in the oob.
- "nand write.jffs2"
- like "nand write" but skip found bad eraseblocks
-
- "nand read.jffs2"
- like "nand read" but skip found bad eraseblocks
-
Miscellaneous and testing commands:
"markbad [offset]"
create an artificial bad block (for testing bad block handling)
projects / karo-tx-uboot.git / blobdiff