genirq: Add support for nested shared IRQs

charleskeepax · KAGA-KOKO · commit 45e5202213ae · 2017-03-11T12:57:03.000+01:00
On a specific audio system an interrupt input of an audio CODEC is used as a shared interrupt. That interrupt input is handled by a CODEC specific irq chip driver and triggers a CPU interrupt via the CODEC irq output line. The CODEC interrupt handler demultiplexes the CODEC interrupt inputs and the interrupt handlers for these demultiplexed inputs run nested in the context of the CODEC interrupt handler. The demultiplexed interrupts use handle_nested_irq() as their interrupt handler, which unfortunately has no support for shared interrupts. So the above hardware cannot be supported. Add shared interrupt support to handle_nested_irq() by iterating over the interrupt action chain. [ tglx: Massaged changelog ] Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com> Cc: patches@opensource.wolfsonmicro.com Link: http://lkml.kernel.org/r/1488904098-5350-1-git-send-email-ckeepax@opensource.wolfsonmicro.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
@@ -348,7 +348,10 @@ void handle_nested_irq(unsigned int irq)
 	irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
 	raw_spin_unlock_irq(&desc->lock);
 
-	action_ret = action->thread_fn(action->irq, action->dev_id);
+	action_ret = IRQ_NONE;
+	for_each_action_of_desc(desc, action)
+		action_ret |= action->thread_fn(action->irq, action->dev_id);
+
 	if (!noirqdebug)
 		note_interrupt(desc, action_ret);
 
