On 2 July 2017 at 18:39, sundeep subbaraya <sundeep.l...@gmail.com> wrote: > I figured out that systick uses cpu clock as clock source and > system_clock_scale > need to be set in msf2-soc.c. There is a bug in u-boot where it uses cpu > clock as > systick input but configures systick in external clock mode. I have tested > the modified > u-boot on real hardware too and it works fine. I am calculating > system_clock_scale > as below: > If CPU clock is X MHz then system_clock_scale = (1 / X) * 1000 > > Tested with different frequencies and they are yielding same results.
If you calculate it like that you'll probably get rounding errors. Better is system_clock_scale = NANOSECONDS_PER_SECOND / freq_in_hz; (Our systick implementation hardwires the external clock frequency at 1MHz, but this is not really correct, it depends on the SoC.) thanks -- PMM
