Hi Thomas, On 11/29/2013 05:28 PM, Thomas Gleixner wrote: > On Fri, 29 Nov 2013, Preeti U Murthy wrote: >> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig >> index b44b52c..cafa788 100644 >> --- a/arch/powerpc/Kconfig >> +++ b/arch/powerpc/Kconfig >> @@ -129,6 +129,8 @@ config PPC >> select GENERIC_CMOS_UPDATE >> select GENERIC_TIME_VSYSCALL_OLD >> select GENERIC_CLOCKEVENTS >> + select GENERIC_CLOCKEVENTS_BROADCAST >> + select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST > > What's the point of this config switch? It's nowhere used.
When broadcast IPIs are to be sent, either the "broadcast" method associated with the local timers is used or an arch-specific method tick_broadcast() is invoked. For the latter be invoked, ARCH_HAS_TICK_BROADCAST config needs to be set. On PowerPC, the broadcast method is not associated with the local timer. Hence we invoke tick_broadcast(). This function has been added in [PATCH 2/9]. > >> +static int broadcast_set_next_event(unsigned long evt, >> + struct clock_event_device *dev) >> +{ >> + return 0; >> +} >> + >> +static void broadcast_set_mode(enum clock_event_mode mode, >> + struct clock_event_device *dev) >> +{ >> + if (mode != CLOCK_EVT_MODE_ONESHOT) >> + broadcast_set_next_event(DECREMENTER_MAX, dev); > > What's the point of calling an empty function? You are right, this should have remained a dummy function like broadcast_set_next_event() as per the design of this patchset. > >> +} >> + >> static void decrementer_set_mode(enum clock_event_mode mode, >> struct clock_event_device *dev) >> { >> @@ -840,6 +869,19 @@ static void register_decrementer_clockevent(int cpu) >> clockevents_register_device(dec); >> } >> >> +static void register_broadcast_clockevent(int cpu) >> +{ >> + struct clock_event_device *bc_evt = &bc_timer; >> + >> + *bc_evt = broadcast_clockevent; >> + bc_evt->cpumask = cpu_possible_mask; >> + >> + printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", >> + bc_evt->name, bc_evt->mult, bc_evt->shift, cpu); >> + >> + clockevents_register_device(bc_evt); >> +} >> + >> static void __init init_decrementer_clockevent(void) >> { >> int cpu = smp_processor_id(); >> @@ -854,6 +896,19 @@ static void __init init_decrementer_clockevent(void) >> register_decrementer_clockevent(cpu); >> } >> >> +static void __init init_broadcast_clockevent(void) >> +{ >> + int cpu = smp_processor_id(); >> + >> + clockevents_calc_mult_shift(&broadcast_clockevent, ppc_tb_freq, 4); >> + >> + broadcast_clockevent.max_delta_ns = >> + clockevent_delta2ns(DECREMENTER_MAX, &broadcast_clockevent); >> + broadcast_clockevent.min_delta_ns = >> + clockevent_delta2ns(2, &broadcast_clockevent); > > clockevents_config() Right, I will change this to call clockevents_config(). I see that this needs to be done during the initialization of the decrementer as well. Will do the same. Thank you Regards Preeti U Murthy > > Thanks, > > tglx > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev