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

[Dmitry Osipenko <digetx@gmail.com>]

05.10.2015 19:27, Peter Crosthwaite пишет:
> On Mon, Oct 5, 2015 at 9:07 AM, Dmitry Osipenko <digetx@gmail.com> wrote:
>> 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.
>>
>
> Great!
>
> Thanks for the efforts. I'll take a CC on the review.
>
> Do on the fly prescaler changes work?
>
> Regards,
> Peter
>
>> --
>> Dmitry

Yes, prescaler works on the fly. I'll post my MPtimer tests somewhere.

-- 
Dmitry