On Tue, May 06, 2014 at 12:46:17AM +0530, pekon gupta wrote: > From: Brian Norris <computersforpe...@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 <computersforpe...@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 <pe...@ti.com>
Applied to u-boot-ti/master, thanks! -- Tom
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