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

[Felipe Balbi]

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.

-- 
balbi