X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=doc%2FREADME.nand;h=2295bb2d962a18e6c57ef415058cfb331ba1db59;hb=f34ccce50a1805a6fdb2d1604ec4e40d79302455;hp=320d752952971a936e36b2cc654f630fa628aa07;hpb=2c3dc792b6df16970077c0d64085e29f1f85d4c8;p=u-boot diff --git a/doc/README.nand b/doc/README.nand index 320d752952..2295bb2d96 100644 --- a/doc/README.nand +++ b/doc/README.nand @@ -94,17 +94,11 @@ Configuration Options: address of u-boot MTD partition in NAND. CONFIG_CMD_NAND - Enables NAND support and commmands. + Enables NAND support and commands. 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. @@ -142,15 +136,8 @@ Configuration Options: 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, @@ -171,7 +158,11 @@ Configuration Options: 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 @@ -194,33 +185,9 @@ Configuration Options: 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_DENALI - Enables the denali.c driver. - - CONFIG_SYS_NAND_DENALI_64BIT - Indicates that the Denali NAND controller is the 64-bit variant. - 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 @@ -304,21 +271,20 @@ Platform specific options However, for 4K pagesize NAND NAND_PAGESIZE = 4096 - NAND_OOBSIZE = 64 + NAND_OOBSIZE = 224 ECC_BYTES = 26 2 + (4096 / 512) * 26 = 210 < NAND_OOBSIZE Thus BCH16 can be supported on 4K page NAND. + 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. + 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 @@ -341,7 +307,7 @@ Miscellaneous and testing commands: DANGEROUS!!! Factory set bad blocks will be lost. Use only to remove artificial bad blocks created with the "markbad" command. - "torture offset" + "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. @@ -358,6 +324,10 @@ Miscellaneous and testing commands: 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)