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

[Felipe Balbi]

On Thu, Feb 24, 2011 at 01:26:05PM +0200, David Cohen wrote:
> 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?

fine by me ;-)

-- 
balbi