Re: [Xenomai-core] Missing IRQ end function on PowerPC

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

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Philippe Gerum wrote:
> Gilles Chanteperdrix wrote:
>> Wolfgang Grandegger wrote:
>>  > Therefore we need a dedicated function to re-enable interrupts in
>> the  > ISR. We could name it *_end_irq, but maybe *_enable_isr_irq is
>> more  > obvious. On non-PPC archs it would translate to *_irq_enable.
>> I  > realized, that *_irq_enable is used in various place/skins and
>> therefore  > I have not yet provided a patch.
>>
>> The function xnarch_irq_enable seems to be called in only two functions,
>> xintr_enable and xnintr_irq_handler when the flag XN_ISR_ENABLE is set.
>>
>> In any case, since I am not sure if this has to be done at the Adeos
>> level or in Xenomai, we will wait for Philippe to come back and decide.
>>
> 
> ->enable() and ->end() all mixed up illustrates a silly x86 bias I once
> had. We do need to differentiate the mere enabling from the IRQ epilogue
> at PIC level since Linux does it - i.e. we don't want to change the
> semantics here.
> 
> I would go for adding xnarch_end_irq -> rthal_irq_end to stick with the
> Linux naming scheme, and have the proper epilogue done from there on a
> per-arch basis.
> 
> Current uses of xnarch_enable_irq() should be reserved to the
> non-epilogue case, like xnintr_enable() i.e. forcibly unmasking the IRQ
> source at PIC level outside of any ISR context for such interrupt (*).
> XN_ISR_ENABLE would trigger a call to xnarch_end_irq, instead of
> xnarch_enable_irq. I see no reason for this fix to leak to the Adeos
> layer, since the HAL already controls the way interrupts are ended
> actually; it just does it improperly on some platforms.
> 
> (*) Jan, does rtdm_irq_enable() have the same meaning, or is it intended
> to be used from the ISR too in order to revalidate the source at PIC level?
> 

Nope, rtdm_irq_enable() was never intended to re-enable an IRQ line
after an interrupt, and the documentation does not suggest this either.
I see no problem here.

Jan


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