On 02/09/15 14:31, Mason wrote: > > My platform provides a 32-bit counter, ticking at a constant 27 MHz. > Reading this counter has a latency of roughly 70 ns (it has to go > over the system memory bus). I think this is good enough for both > the clock source and sched_clock, is it not? > > So the plan would be: > - clocksource and sched_clock : 27 MHz, 32-bit counter, platform > - clockevents : TWD, standard Yep, that sounds like a good plan. If your platform has the ARM global timer (drivers/clocksource/arm_global_timer.c) then you don't need anything besides that timer because it provides both the clocksource, sched_clock, and clockevents. Sounds like you don't have that timer though, so you have to write a driver for your custom platform timer and at least hook up clocksource and sched_clock to it. If you have interrupts with your platform timer you can skip out on TWD and also register a clockevent in your platform timer driver. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
