[U-Boot] [PATCH] mmc: bcm2835: fix delays in bug workaround

[Stephen Warren]

On 03/22/2013 12:41 AM, Albert ARIBAUD wrote:
> Hi Stephen,
> 
> On Thu, 21 Mar 2013 22:02:18 -0600, Stephen Warren
> <swarren at wwwdotorg.org> wrote:
> 
>> The back-to-back-writes workaround in the BCM2835 MMC driver assumed
>> that get_timer() returned uS. Now that it returns mS, the delay is far
>> too long. Use udelay() directly to avoid this. Dispense with the
>> "last_write" code since we now have no way of recording an absolute
>> time in uS. The difference between two un-averaged tests loading a
>> zImage is 445 mS vs the original 412 mS, so the difference doesn't
>> appear too relevant.
> 
> I don't entirely get the 'we have no way of recording an absolute time
> in us': doesn't get_timer_us() precisely provide this absolute us time
> just like 'old' get_timer(base) did? IOW, could you not simply turn
> every get_timer(X) into (get_timer_us()-X)?

Well, I could do that, but that's an internal private API inside
timer.c, not something exported. Should I explicitly export it and allow
the driver to use that?