Re: [Adeos-main] [git pull] Updates for ipipe-2.6.36-noarch

[Jan Kiszka <jan.kiszka@domain.hid>]

On 2011-01-18 18:37, Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> On 2011-01-18 18:27, Philippe Gerum wrote:
>>> On Tue, 2011-01-18 at 18:22 +0100, Jan Kiszka wrote:
>>>> On 2011-01-18 18:13, Philippe Gerum wrote:
>>>>> On Thu, 2010-11-25 at 17:33 +0100, Jan Kiszka wrote:
>>>>>> The following changes since commit 4c83ab8e3ac5b194695e38bbc253f78e6072ad24:
>>>>>>
>>>>>>   ipipe: tell __ipipe_run_irqtail about the latest IRQ number (2010-11-05 13:52:55 +0100)
>>>>>>
>>>>>> are available in the git repository at:
>>>>>>   git://git.kiszka.org/ipipe-2.6 queues/2.6.35-noarch
>>>>>>
>>>>>> [edited log]
>>>>>> Jan Kiszka (4):
>>>>>>       ipipe: Provide wrapper for IRQ mask/unmask at chip level
>>>>> Could you give me some hints about the intended usage of these?
>>>> The idea was (and still is but effort stalled ATM) to emulate MSI
>>>> masking on top of that.
>>> Ok, let's keep this on the shelf until we come with a complete solution.
>>> I suspect we will have to resync the Xenomai and I-pipe interfaces to
>>> this end.
>>
>> Definitely. So the patch was intended as a starting point, enbling
>> refactoring on Xenomai side. Quite a lot of work is actually to be done
>> on the rthal, also to clean up lots of duplicate irq descriptor
>> translations over there.
> 
> As a maintainer of low end architectures, I am not too fond with
> introducing one more level of function pointers. A substantial part of
> the worst case interrupt latency on ARM is spent in these routines, so,
> it would be nice if we could avoid make this even longer. And still on
> ARM, acking/masking an interrupt line is just about writing some bit to
> some MMIO memory, so, the cost of the function pointer is definitely not
> negligible.

Then we need to push the definition of ipipe_irq_chip_[un]mask into arch
hands and effectively keep it for those setups as is which do not need
more. But we do need this abstraction.

Jan

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