On Friday, July 13, 2018, [email protected] wrote: > > Exactly what the level of software support is available for the ARM > > timers at this point I'm not so sure about. > > Using the TWD timer indeed has two issues: > - It's available on multi-core Cortex-A9 SoCs only, > - Its driver does not call register_current_timer_delay(), so it doesn't > set > up lpj_fine for skipping loop calibration. > > The global timer driver does call register_current_timer_delay(), but so > far no > Renesas SoCs describe its presence in DT. > > At least SH-Mobile AG5 and R-Car M1A and H1 seem to have it. > RZ/A1 (and A2) and R-Mobile A1 don't seem to have it, though. > Perhaps the call to register_current_timer_delay() could be added to > the RZ/A OSTM driver?
For RZ/A1, technically you could use MTU2 or OSTM as your system timer. However, no one would every use MTU2 because OSTM is way more accurate. Regardless, would we always call register_current_timer_delay() from the OSTM driver? Note that there are 2 OSTM channels on RZ/A1. The first one is loaded as a clocksource, the second is used as an event counter. Would we call register_current_timer_delay() for both instances? Chris
