[U-Boot] [PATCH v2 05/16] sunxi: dram: Remove broken impedance and ODT configuration code

[Ian Campbell]

On Sun, 2014-08-03 at 05:32 +0300, Siarhei Siamashka wrote:
> We can safely remove it, because none of the currently supported
> boards uses these features.
> 
> The existing implementation had multiple problems:
>    - unnecessary code duplication between sun4i/sun5i/sun7i
>    - ZQ calibration was never initiated explicitly, and could be
>      only triggered by setting the highest bit in the 'zq' parameter
>      in the 'dram_para' struct (this was never actually done for
>      any of the known Allwinner devices).
>    - even if the ZQ calibration could be started, no attempts were
>      made to wait for its completion, or checking whether the
>      default automatically initiated ZQ calibration is still
>      in progress
>    - ODT was only ever enabled on sun4i, but not on sun5i/sun7i
> 
> Additionally, SDR_IOCR was set to 0x00cc0000 only on sun4i. There
> are some hints in the Rockchip Linux kernel sources, indicating
> that these bits are related to the automatic I/O power down
> feature, which is poorly understood on sunxi hardware at the
> moment. Avoiding to set these bits on sun4i too does not seem to
> have any measurable/visible impact.
> 
> The impedance and ODT configuration code will be re-introdeced in
> one of the next comits.
> 
> Signed-off-by: Siarhei Siamashka <siarhei.siamashka at gmail.com>

Acked-by: Ian Campbell <ijc at hellion.org.uk>