Re: [PATCH 1/2] xen: arm: log warning for interrupt configuration mismatch

[Julien Grall <julien.grall@linaro.org>]

On 02/03/15 13:42, Ian Campbell wrote:
>>> I even reread the spec before sending and reached the same conclusion,
>>> but apparently managed to fail to change the actual code!
>>>
>>> Question is -- what to do about PPIs, since the CFG register cannot
>>> express the polarity of the edge or level. I suppose we may as well just
>>> assume the one that is compatible with SPIs, since we have nothing
>>> better to go on.
>>
>> Linux seems to set edge (resp. level) bit for any edge (resp. level)
>> type interrupts.
> 
> Right, sorry I wasn't clear. We should obviously do this too when
> writing to ICFG (I believe we do), the case I was talking about was the
> one relating to the quoted code above: when we read back ICFG and find
> that the setting hasn't taken. In that case we want to update
> desc->arch.type to somehow reflect "reality", which requires us to
> fabricate a polarity for the interrupt (rising/falling or low/high).

desc->arch.type is only used in Xen for IRQ configuration.

Given that, I was wondering if it would be useful to only store
EDGE/LEVEL in the desc->arch.type and, therefore, ignoring
rising/falling and low/high.

That would make the code simpler.

Regards,

-- 
Julien Grall