On 13/06/16 12:09, Jon Hunter wrote: > > On 13/06/16 11:42, Marc Zyngier wrote: >> On 07/06/16 16:12, Jon Hunter wrote: >>> For some devices the IRQ trigger type for a device is read from >>> firmware, such as device-tree. The IRQ trigger type is typically read >>> when the mapping for IRQ is created, which is before the IRQ is >>> requested. Hence, the IRQ trigger type is programmed when mapping the >>> IRQ and not when requesting the IRQ. >>> >>> Although this works for most cases, in order to support IRQ chips which >>> require runtime power management, which may not be accessible prior >>> to requesting the IRQ, it is desirable to look-up the IRQ trigger type >>> when it is requested. Therefore, if the IRQ trigger type is not >>> specified when __setup_irq() is called, look-up the saved IRQ trigger >>> type. This will allow us to defer the programming of the trigger type >>> from when the IRQ is mapped to when it is actually requested. >>> >>> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx> >>> Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx> >>> --- >>> kernel/irq/manage.c | 7 +++++++ >>> 1 file changed, 7 insertions(+) >>> >>> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c >>> index ef0bc02c3a70..eaedeb74b49d 100644 >>> --- a/kernel/irq/manage.c >>> +++ b/kernel/irq/manage.c >>> @@ -1117,6 +1117,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) >>> new->irq = irq; >>> >>> /* >>> + * If the trigger type is not specified by the caller, >>> + * then use the default for this interrupt. >>> + */ >>> + if (!(new->flags & IRQF_TRIGGER_MASK)) >>> + new->flags |= irqd_get_trigger_type(&desc->irq_data); >>> + >>> + /* >>> * Check whether the interrupt nests into another interrupt >>> * thread. >>> */ >>> >> >> I've added the following patch to the queue, in order to deal with >> percpu interrupts that were not handled by this patch: >> >> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c >> index f8fd1fb..00cfc85 100644 >> --- a/kernel/irq/manage.c >> +++ b/kernel/irq/manage.c >> @@ -1751,7 +1751,14 @@ void enable_percpu_irq(unsigned int irq, unsigned int type) >> if (!desc) >> return; >> >> + /* >> + * If the trigger type is not specified by the caller, then >> + * use the default for this interrupt. >> + */ >> type &= IRQ_TYPE_SENSE_MASK; >> + if (type == IRQ_TYPE_NONE) >> + type = irqd_get_trigger_type(&desc->irq_data); >> + > > I am wondering if you need this here because now __setup_irq(), called > by request_percpu_irq(), will actually look-up the saved type even for a > percpu-irq. So shouldn't this already be handled? Or am I missing something? You are overlooking the fact that the configuration registers are themselves per-CPU, which means that __setup_irq() will only configure the interrupt on the CPU it runs on. And you can't even tell which one, since you are in a preemptible context. Does it make more sense? 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
