[RFC/NOT FOR MERGING] HACK: add global/private timers for A9

[Mason]

On 04/06/2015 22:37, Felipe Balbi wrote:
> On Thu, Jun 04, 2015 at 10:32:40PM +0200, Mason wrote:
>> On 04/06/2015 22:08, Felipe Balbi wrote:
>>
>>> On Thu, Jun 04, 2015 at 11:46:59AM +0200, Mason wrote:
>>>> Also, check /proc/timer_list for a "Broadcast device". If you don't
>>>> define one, the TWD timers are set to periodic mode, with hrtimers
>>>> disabled.
>>>
>>> Did you manage to turn global timer into Broadcast device ?
>>
>> Disclaimer: I am a kernel noob, take everything I say with
>> a rock of salt.
>>
>> As far as I can see, the global timer code doesn't handle
>> frequency changes, whereas the TWD code does.
> 
> All right, but TWD has C3STOP and that prevents it from being used as
> broadcast device.

AFAICT, my platform doesn't stop the local timers in low-power
mode, so I just dropped the CLOCK_EVT_FEAT_C3STOP flag.

There's even a patch approved by Arnd somewhere in the thread,
although he did recommend I should investigate to understand
the problem better.

Regards.