irqchip: sun4i: Don't ack IRQs > 0, fix acking of IRQ 0

All IRQs except for IRQ 0 seem to not need acking, so drop acking for them.

The ENMI needs to have the ack done *after* clearing the interrupt source,
otherwise we will get a spurious interrupt for each real interrupt.

So use the new IRQCHIP_EOI_THREADED flag for this in combination with
handle_fasteoi_irq. This uses a separate irq_chip struct for IRQ 0,
since we only want this behavior for IRQ 0.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@googlegroups.com
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: http://lkml.kernel.org/r/1394733834-26839-5-git-send-email-hdegoede@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/irqchip/irq-sun4i.c

@@ -76,16 +76,29 @@ static void sun4i_irq_unmask(struct irq_data *irqd)
 
 static struct irq_chip sun4i_irq_chip = {
 	.name		= "sun4i_irq",
-	.irq_ack	= sun4i_irq_ack,
 	.irq_mask	= sun4i_irq_mask,
 	.irq_unmask	= sun4i_irq_unmask,
 };
 
+/* IRQ 0 / the ENMI needs a late eoi call */
+static struct irq_chip sun4i_irq_chip_enmi = {
+	.name		= "sun4i_irq",
+	.irq_eoi	= sun4i_irq_ack,
+	.irq_mask	= sun4i_irq_mask,
+	.irq_unmask	= sun4i_irq_unmask,
+	.flags		= IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED,
+};
+
 static int sun4i_irq_map(struct irq_domain *d, unsigned int virq,
 			 irq_hw_number_t hw)
 {
+	if (hw == 0)
+		irq_set_chip_and_handler(virq, &sun4i_irq_chip_enmi,
+					 handle_fasteoi_irq);
+	else
 		irq_set_chip_and_handler(virq, &sun4i_irq_chip,
 					 handle_level_irq);
+
 	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
 
 	return 0;