On Wed, Feb 23, 2011 at 10:09 PM, Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Guzman Lugo, Fernando wrote: >> Hi, > > Hi Fernando, > >> 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 > well, won't there? That's really a good point. callbacks in this situation are mostly to debug purpose. Drivers shouldn't rely on that to work properly. David > >> iommu <---- register fault callback for error notify driver >> >> instead of >> >> iommu <--- register fault callback for remote processor driver >> <----register fault event for error notify driver. >> >> with that, we remove one dependency of the errornotify driver. > > I suppose this is not in mainline? > > Regards, > > -- > Sakari Ailus > sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at Âhttp://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
