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

Andy Fleming afleming at gmail.com
Mon Sep 5 00:45:00 CEST 2011


On Sun, Sep 4, 2011 at 5:18 PM, Marek Vasut <marek.vasut at gmail.com> wrote:
> On Saturday, September 03, 2011 05:34:17 AM Lei Wen wrote:
>> For some controller it has dynamic clock gating, and only toggle out clk
>> when the first cmd0 send out, while some card strictly obey the 74
>> clocks rule, the interval may not be sufficient between the cmd0 and
>> this cmd8, retry to fulfil the clock requirement.


This seems like the wrong way to handle this. What if another
controller shows up, but it takes *4* retries. Or *5*?

Or *100*? This sort of knowledge should somehow be embedded in either
the driver for that controller, or the board
code. Not the generic MMC code.

Maybe put it in the init code for the controller?

Andy


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