On Mon, Jan 22, 2018 at 10:49 AM, Greentime Hu <green.hu@xxxxxxxxx> wrote: > 2018-01-20 0:41 GMT+08:00 Arnd Bergmann <arnd@xxxxxxxx>: >>> This implementation is referenced from openrisc. >>> https://lkml.org/lkml/2017/11/17/228 >> >> It's correct on openrisc, because that has a reliable cycle counter, >> and that gets used in its delay function: >> >> void __delay(unsigned long cycles) >> { >> cycles_t start = get_cycles(); >> while ((get_cycles() - start) < cycles) >> cpu_relax(); >> } >> >> In my review comment that you cited, I assumed that nds32 had similar >> hardware. >> >> However, as you explained earlier, the nds32 architecture does not provide >> a cycle counter and the clocksource resolution is not high enough to >> be a good replacement, so you have to use the traditional delay >> calibration. >> > > Hi, Arnd: > > Thank you for your explanation. > Will it be ok if I code it like this? > > config GENERIC_CALIBRATE_DELAY > def_bool y Yes, I think that should be sufficient. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
