On 20/04/16 12:03, Jon Hunter wrote: > When mapping an IRQ, it is possible that a mapping for the IRQ already > exists. If mapping does exist then there are the following issues with > regard to the handling of the IRQ type settings ... > 1. If the domain is part of a hierarchy, then: > a. We do not check that the type settings for the existing mapping > match those of the new mapping. > b. We do not check to see if the type settings have been programmed > yet (and they might not have been) and so we may never set the > type. > 2. If the domain is NOT part of a hierarchy, we will overwrite the > current type settings programmed if they are different from the > previous mapping. Please note that irq_create_mapping() > calls irq_find_mapping() to check if a mapping already exists. > > Although, it may be unlikely that the type settings for a shared > interrupt would not match, nonetheless we should check for this. > Therefore, to fix this check if a mapping exists (regardless of whether > the domain is part of a hierarchy or not) and if it does then: > 1. Return the IRQ number if the type settings match or are not > specified. > 2. Program the type settings and return the IRQ number if the type > settings have not been programmed yet. > 3. Otherwise if the type setting do not match, then print a warning > and don't return the IRQ number. > > Furthermore, add a warning if the type return by irq_domain_translate() > has bits outside the sense mask set and then clear these bits. If these > bits are not cleared then this will cause the comparision of the type > settings for an existing mapping to fail with that of the new mapping > even if the sense bit themselves match. The reason being is that the > existing type settings are read by calling irq_get_trigger_type() which > will clear any bits outside the sense mask. This will allow us to detect > irqchips that are not correctly clearing these bits and fix them. > > Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx> Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx> M. -- Jazz is not dead. It just smells funny... -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
