Re: [Qemu-devel] [RFC v1 0/2] ARM MPTimer fixes and refactoring

[Dmitry Osipenko <digetx@gmail.com>]

03.10.2015 16:11, Dmitry Osipenko пишет:
> 20.09.2015 20:48, Peter Crosthwaite пишет:
>> On Sun, Jul 5, 2015 at 1:58 PM, Peter Crosthwaite
>> <peter.crosthwaite@xilinx.com> wrote:
>>> On Sun, Jul 5, 2015 at 1:47 PM, Dmitry Osipenko <digetx@gmail.com> wrote:
>>>> 05.07.2015 23:26, Peter Crosthwaite пишет:
>>>>
>>>>> Hi Dmitry,
>>>>>
>>>>> Based on my comment earlier, this is what I came up with RE consolidation
>>>>> of
>>>>> those arm_mptimer code paths that were giving you problems. I have not
>>>>> done the
>>>>> interrupt mask fix, as that one from your series is reasonably
>>>>> independent.
>>>>>
>>>>> Regards,
>>>>> Peter
>>>>>
>>>>> Peter Crosthwaite (2):
>>>>>     timer: arm_mp: Factor out timer value calculation
>>>>>     timer: arm_mp: consolidate control and counter write logic
>>>>>
>>>>>    hw/timer/arm_mptimer.c | 73
>>>>> +++++++++++++++++++++++++++++---------------------
>>>>>    1 file changed, 42 insertions(+), 31 deletions(-)
>>>>>
>>>>
>>>> Hi Peter, thanks a lot! Generally, I don't have any trouble with currently
>>>> missed functionality, just noticed it while was hacking my NVIDIA Tegra2
>>>> emulation pet-project and decided to contribute =).
>>>>
>>>> It looks like you are trying to duplicate what generic ptimer is already
>>>> doing, isn't it?
>>>>
>>>
>>> Yes, ptimer was probably the correct way to do this in the first
>>> place. Some of the new code structures introduced in this patch series
>>> are directly applicable though for that conversion effort.
>>>
>>
>> I looked into doing this with ptimer, and pitmer doesn't really play
>> nice with periodic down counters. You could do the subtractions
>> against an up counter with the load value but that seems just as
>> complex as the current solution IMO. The hardest part is setting the
>> counter value on an already running timer.
>>
>> The alternative is to patch ptimer to handle down timers.
>>
>> Regards,
>> Peter
>>
>
> Hmm, I think you missed something. Ptimer is doing downcount, not up.
> ptimer_get_count() might be a misnomer, it returns current timer value (it goes
> down to 0), not a passed ticks count number. Ptimer also should handle reloading
> of a running timer just fine with ptimer_set_count(), don't see any trouble
> here. Anyway, I'll try to re-implement MPtimer using ptimer ASAP and see how it
> really fits.
>

Finally, I tried ptimer and everything seem to work perfect. Pausing, 
re-loading, etc works as it should. Will send the patch soon.

-- 
Dmitry