On 03/22/2013 12:41 AM, Albert ARIBAUD wrote:
Hi Stephen,
On Thu, 21 Mar 2013 22:02:18 -0600, Stephen Warren swarren@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?