[PATCH v3 2/2] OMAP: IOMMU: add support to callback during fault handling

[David Cohen]

On Thu, Feb 24, 2011 at 10:35 AM, Felipe Balbi <balbi at ti.com> wrote:
> Hi,
>
> On Wed, Feb 23, 2011 at 10:09:05PM +0200, Sakari Ailus wrote:
>> > In OMAP4 the cortex M3 is a double core processor and as each core is
>> > running they own version of the RTOS we threat them independently. So
>> > our driver which controls the remote processor sees two processor but
>> > both use the same iommu hw. When a iommu fault happens, at this
>> > moment, it is consider as a faltal error and it is no managed to
>> > recover and continue, instead a restart of the processor is needed, if
>> > the fault happens in core0 we need to reset core1 too and vice versa.
>> > if the iommu would support several user callbacks, we can register the
>> > callback which resets core0 and also the callback which resets core1
>> > and treat them as totally independent processors. Also we have an
>> > error event notifier driver, which is only in charge of notifying
>> > error events to userspace, so we would have multiple callbacks we
>> > could do this
>>
>> The original purpose of the patch, as far as I understand, is to allow
>> getting useful information for debugging purposes should an iommu fault
>> happen.
>>
>> Also, I'm not sure it's necessarily a good idea to just go and reset
>> the M3 cores in case an iommu fault happens --- this is very probably a
>> grave bug in the software running on those M3s. It should be fixed
>> instead of just hiding it. There will be consequences to host side as
>
> I have to agree here. Besides the fact that multiple callbacks is
> outside the scope of this patch.

This patch is already acked. What about leave it as it is and discuss
multiple callbacks before release a new patch to support it?

Br,

David

>
> --
> balbi
>