[U-Boot-Users] PXA270 support
Woodruff, Richard
r-woodruff2 at ti.com
Mon Mar 14 23:16:24 CET 2005
Wolfgang,
> Note: this is BROKEN.
>
> CFG_HZ should be 1000 on all boards. it has NOTHING to do with any
> clock frequencies of your baord or processor (yes, I know that quite
> a lot of boards are broken this way).
Why is this? The common use seems to be many flash drivers may get a
time source directly and need to normalize the number of ticks to a
second's value. I know I set up my timer with the CFG_HZ value in mind
to gauge udelays.
void udelay (unsigned long usec)
{
ulong tmo, tmp;
if (usec >= 1000) {/* if "big" number, spread normalization to seconds
*/
tmo = usec / 1000;/* start to normalize for usec to ticks per sec */
tmo *= CFG_HZ;/* find number of "ticks" to wait to achieve target */
tmo /= 1000;/* finish normalize. */
} else {/* else small number, don't kill it prior to HZ multiply */
tmo = usec * CFG_HZ;
tmo /= (1000*1000);
}
...
How is 1000 correct? That doesn't seem to follow.
Regards,
Richard W.
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