Re: [Xen-devel] [for-4.7 1/5] drivers/pl011: ACPI: The interrupt should always be high level triggered

[Shannon Zhao <shannon.zhao@xxxxxxxxxx>]

On 2016年04月07日 21:41, Julien Grall wrote:
> 
> On 07/04/16 13:30, Shannon Zhao wrote:
>>
>>
>> On 2016/4/7 18:59, Julien Grall wrote:
>>> The SPCR does not specify if the interrupt is edge or level triggered.
>>> So the configuration needs to be hardcoded in the code.
>>>
>>> Based on the PL011 TRM (see 2.2.8 in ARM DDI 0183G), the interrupt
>>> generated
>>> will be active high. This wording implies the interrupt should be
>>> high level
>>> triggered.
>> I think active high can stand rising edge triggered for edge triggered
>> interrupt.
>>
>> E.g. see "Table 5-118 Flag Definitions: Virtual Timer, EL2 timers, and
>> Secure & Non-Secure EL1 timers" in ACPI SPEC 6.0.
> 
> I've spoken with multiple person about the wording and the consensus is
> "active high" would imply high level triggered. So it's very ambiguous.
> 
> However, the PL011 is always using a high level triggered. You can look
> at the device tree bindings such as the one for the foundation model.
> 
> Also, the SBSA (section 4.3.2 in ARM-DEN-0029 v2.3) states the PL011
> implemented with a level triggered interrupt.
> 
> Note, I wasn't able to get the serial console working on my platform
> with edge triggered interrupt.

So how about IRQ_TYPE_LEVEL_HIGH instead of IRQ_TYPE_LEVEL_MASK?

Thanks,
-- 
Shannon

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