[U-Boot] [PATCH] cfi_flash: Fix detection of 8-bit bus flash devices via address shift

[Stefan Roese]

Hi Wolfgang,

On 06/07/2013 03:02 PM, Jagannadha Sutradharudu Teki wrote:
> We had a problem detecting 8/16bit flash devices connected only via
> 8bits to the SoC for quite a while. Commit 239cb9d9
> [mtd: cfi_flash: Fix CFI flash driver for 8-bit bus support] finally
> fixed this 8-bit bus support. But also broke some other boards using
> this cfi driver. So this patch had to be reverted.
> 
> I spotted a different, simpler approach for this 8-bit bus support
> on the barebox mailing list posted by
> Oleksij Rempel <bug-track at fisher-privat.net>:
> 
> http://www.spinics.net/lists/u-boot-v2/msg14687.html
> 
> Here the commit text:
> 
> "
> Many cfi chips support 16 and 8 bit modes. Most important
> difference is use of so called "Q15/A-1" pin. In 16bit mode this
> pin is used for data IO. In 8bit mode, it is an address input
> which add one more least significant bit (LSB). In this case
> we should shift all adresses by one:
> For example 0xaa << 1 = 0x154
> "
> 
> This patch now is a port of this barebox patch to U-Boot.
> 
> Along with the change w.r.t from barebox,
> Some flash chips can support multiple bus widths, override the
> interface width and limit it to the port width.
> 
> Tested on 16-bit Spansion flash on sequoia.
> Tested 8-bit flashes like 256M29EW, 512M29EW.
> 
> Signed-off-by: Stefan Roese <sr at denx.de>
> Tested-by: Jagannadha Sutradharudu Teki <jaganna at xilinx.com>

Wolfgang, you remember that s few weeks ago a similar CFI patch resulted
in breaking flash support for one TQ board. Which one was that? Could
you please either test this patch on this board or let me know which
board this was? Then I'll do the testing next week.

Thanks,
Stefan

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