On Tue, May 06, 2014 at 12:46:19AM +0530, pekon gupta wrote:
GPMC controller needs to be configured based on bus-width of the NAND device connected to it. Also, dynamic detection of NAND bus-width from on-chip ONFI parameters is not possible in following situations: SPL: SPL NAND drivers does not support ONFI parameter reading. U-boot: GPMC controller iniitalization is done in omap_gpmc.c:board_nand_init() which is called before probing for devices, hence any ONFI parameter information is not available during GPMC initialization.
Thus, OMAP NAND driver expected board developers to explicitely write GPMC configurations specific to NAND device attached on board in board files itself. But this was troublesome for board manufacturers as they need to dive into lengthy platform & SoC documents to find details of GPMC registers and appropriate configurations to get NAND device working.
This patch instead adds existing CONFIG_SYS_NAND_BUSWIDTH_16BIT to board config hich indicates that connected NAND device has x16 bus-width. And then based on this config GPMC driver itself initializes itself based on NAND bus-width. This keeps board developers free from knowing GPMC controller specific internals.
Signed-off-by: Pekon Gupta pekon@ti.com
Applied to u-boot-ti/master, thanks!