Enable arm_global_timer for Zynq brakes boot
Sören Brinkmann
soren.brinkmann at xilinx.com
Fri Aug 16 13:28:38 EDT 2013
On Mon, Aug 12, 2013 at 07:02:39PM +0200, Daniel Lezcano wrote:
> On 08/12/2013 06:53 PM, Sören Brinkmann wrote:
> > On Mon, Aug 12, 2013 at 06:49:17PM +0200, Daniel Lezcano wrote:
> >> On 08/12/2013 06:32 PM, Sören Brinkmann wrote:
> >>> On Mon, Aug 12, 2013 at 09:20:19AM -0700, Stephen Boyd wrote:
> >>>> On 08/12/13 09:03, Sören Brinkmann wrote:
> >>>>> On Fri, Aug 09, 2013 at 10:27:57AM -0700, Stephen Boyd wrote:
> >>>>>> On 08/09, Daniel Lezcano wrote:
> >>>>>>> yes, but at least the broadcast mechanism should send an IPI to cpu0 to
> >>>>>>> wake it up, no ? As Stephen stated this kind of configuration should has
> >>>>>>> never been tested before so the tick broadcast code is not handling this
> >>>>>>> case properly IMHO.
> >>>>>>>
> >>>>>> If you have a per-cpu tick device that isn't suffering from
> >>>>>> FEAT_C3_STOP why wouldn't you use that for the tick versus a
> >>>>>> per-cpu tick device that has FEAT_C3_STOP? It sounds like there
> >>>>>> is a bug in the preference logic or you should boost the rating
> >>>>>> of the arm global timer above the twd. Does this patch help? It
> >>>>>> should make the arm global timer the tick device and whatever the
> >>>>>> cadence timer you have into the broadcast device.
> >>>>> I finally got to test your patch. Unfortunately, it makes the system
> >>>>> hang even earlier:
> >>>>
> >>>> Sorry it had a bug depending on the registration order. Can you try this
> >>>> one (tabs are probably spaces, sorry)? I will go read through this
> >>>> thread to see if we already covered the registration order.
> >>>
> >>> That did it! Booted straight into the system.
> >>
> >> Good news :)
> >>
> >>> The broadcast device is
> >>> the TTC instead of GT, now.
> >>>
> >>> Tick Device: mode: 1
> >>> Broadcast device
> >>> Clock Event Device: ttc_clockevent
> >>> max_delta_ns: 1207932479
> >>> min_delta_ns: 18432
> >>> mult: 233015
> >>> shift: 32
> >>> mode: 1
> >>> next_event: 9223372036854775807 nsecs
> >>> set_next_event: ttc_set_next_event
> >>> set_mode: ttc_set_mode
> >>> event_handler: tick_handle_oneshot_broadcast
> >>> retries: 0
> >>>
> >>> tick_broadcast_mask: 00000000
> >>> tick_broadcast_oneshot_mask: 00000000
> >>
> >> At the first glance, the timer broadcast usage is not set, right ? Can
> >> you try with the cpuidle flag even if it is not needed ?
> >
> > It's actually present. I have a clean 3.11-rc3 and the only changes are
> > my patch to enable the GT and Stephen's fix.
> > The cpuidle stats show both idle states being used.
>
> Ah, right. The tick_broadcast_mask is not set because the arm global
> timer has not the CLOCK_EVT_FEAT_C3STOP feature flag set.
Just to check in. Do you want any additional testing done? Or can I
expect Stephens fix to get merged, so Zynq can use the GT?
Thanks,
Sören
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