On Tue, May 06, 2014 at 12:46:17AM +0530, pekon gupta wrote:
From: Brian Norris computersforpeace@gmail.com
As per following Sections in ONFI Spec, NAND_CMD_READID should use only lower 8-bit for transfering command, address and data even on x16 NAND device.
*Section: Target Initialization" "The Read ID and Read Parameter Page commands only use the lower 8-bits of the data bus. The host shall not issue commands that use a word data width on x16 devices until the host determines the device supports a 16-bit data bus width in the parameter page."
*Section: Bus Width Requirements* "When the host supports a 16-bit bus width, only data is transferred at the 16-bit width. All address and command line transfers shall use only the lower 8-bits of the data bus. During command transfers, the host may place any value on the upper 8-bits of the data bus. During address transfers, the host shall set the upper 8-bits of the data bus to 00h."
Thus porting following commit from linux-kernel to ensure that column address is not altered to align to x16 bus when issuing NAND_CMD_READID command.
commit 3dad2344e92c6e1aeae42df1c4824f307c51bcc7 mtd: nand: force NAND_CMD_READID onto 8-bit bus Author: Brian Norris <computersforpeace@gmail.com> (preserving authorship) The NAND command helpers tend to automatically shift the column address for x16 bus devices, since most commands expect a word address, not a byte address. The Read ID command, however, expects an 8-bit address (i.e., 0x00, 0x20, or 0x40 should not be translated to 0x00, 0x10, or 0x20). This fixes the column address for a few drivers which imitate the nand_base defaults.Signed-off-by: Pekon Gupta pekon@ti.com
Applied to u-boot-ti/master, thanks!