[U-Boot] Revert "mmc: retry the cmd8 to meet 74 clocks requirement in the spec"

[Pali Rohár]

On Saturday 19 November 2011 12:36:00 Stephen Warren wrote:
> On 01/-10/-28163 12:59 PM, Macpaul Lin wrote:
> > This reverts commit 02f3029f1810b99869254d0cf0a71946a008a728.
> > 
> > This patch add 3 times retry to CMD8 because the Marvell mmc controller
> > doesn't obey the power ramp up process in the SD specification 6.4.1.
> > (Please refer to figure 6.1 and 6.2 in the specification.)
> > 
> > The CMD0 should be send after power ramp up has been finished.
> > However, the Marvell mmc contorller must do power ramp up after the
> > first CMD0 command has been send.
> > 
> > This patch also affect existing platforms like Nokia N900 and other
> > platforms.
> > 
> > Signed-off-by: Macpaul Lin <macpaul at andestech.com>
> > Acked-by: Lei Wen <leiwen at marvell.com>
> 
> Acked-by: Stephen Warren <swarren at nvidia.com>
> Tested-by: Stephen Warren <swarren at nvidia.com>
> 
> As background, I'm working on patches to support the Toshiba AC100 /
> Dynabook AZ in mainline U-Boot. The internal MMC didn't work at all
> until this revert was applied. The SD slot worked perfectly though. I
> guess this is related to the MMC itself not supporting this
> (SD-specific?) command, and the patch caused MMC mode never to be attempted.

Same for Nokia N900 (SD slot working fine). After reverting commit 
02f3029f1810b99869254d0cf0a71946a008a728 internal eMMC working too.

-- 
Pali Rohár
pali.rohar at gmail.com
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