genirq: Simplify wakeup mechanism

Currently we suspend wakeup interrupts by lazy disabling them and
check later whether the interrupt has fired, but that's not sufficient
for suspend to idle as there is no way to check that once we
transitioned into the CPU idle state.

So we change the mechanism in the following way:

1) Leave the wakeup interrupts enabled across suspend

2) Add a check to irq_may_run() which is called at the beginning of
   each flow handler whether the interrupt is an armed wakeup source.

   This check is basically free as it just extends the existing check
   for IRQD_IRQ_INPROGRESS. So no new conditional in the hot path.

   If the IRQD_WAKEUP_ARMED flag is set, then the interrupt is
   disabled, marked as pending/suspended and the pm core is notified
   about the wakeup event.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ rjw: syscore.c and put irq_pm_check_wakeup() into pm.c ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 19 insertions, 1 deletions

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 6baf86085571..e7917ff8a486 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -344,8 +344,26 @@ static bool irq_check_poll(struct irq_desc *desc)
 
 static bool irq_may_run(struct irq_desc *desc)
 {
-	if (!irqd_irq_inprogress(&desc->irq_data))
+	unsigned int mask = IRQD_IRQ_INPROGRESS | IRQD_WAKEUP_ARMED;
+
+	/*
+	 * If the interrupt is not in progress and is not an armed
+	 * wakeup interrupt, proceed.
+	 */
+	if (!irqd_has_set(&desc->irq_data, mask))
 		return true;
+
+	/*
+	 * If the interrupt is an armed wakeup source, mark it pending
+	 * and suspended, disable it and notify the pm core about the
+	 * event.
+	 */
+	if (irq_pm_check_wakeup(desc))
+		return false;
+
+	/*
+	 * Handle a potential concurrent poll on a different core.
+	 */
 	return irq_check_poll(desc);
 }