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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/README.nand | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/doc/README.nand b/doc/README.nand index b91f198..2bc5b39 100644 --- a/doc/README.nand +++ b/doc/README.nand @@ -190,6 +190,24 @@ 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 ========================= |