[PATCH 2/2] IRQCHIP: bcm7120-l2: perform suspend/resume even without installed child IRQs

[Brian Norris <computersforpeace@gmail.com>]

Make use of the new irq_chip chip_{suspend,resume} callbacks.

This is required because if there are no installed child IRQs for
this chip, the irq_{suspend,resume} functions will not be called.
However, we still need to save/restore the forwarding mask, to enable
the top-level GIC interrupt; otherwise, we lose UART output after S3
resume.

In addition to refactoring the callbacks, we have to self-initialize the
mask cache, since the genirq core also doesn't initialize this until the
first child IRQ is installed.

The original problem report is described in extra detail here:
http://lkml.kernel.org/g/20150619224123.GL4917@ld-irv-0074

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
 drivers/irqchip/irq-bcm7120-l2.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/irqchip/irq-bcm7120-l2.c b/drivers/irqchip/irq-bcm7120-l2.c
index 299d4de2deb5..98f0129fe843 100644
--- a/drivers/irqchip/irq-bcm7120-l2.c
+++ b/drivers/irqchip/irq-bcm7120-l2.c
@@ -81,10 +81,9 @@ static void bcm7120_l2_intc_irq_handle(unsigned int irq, struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
-static void bcm7120_l2_intc_suspend(struct irq_data *d)
+static void bcm7120_l2_intc_suspend(struct irq_chip_generic *gc)
 {
-	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
-	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+	struct irq_chip_type *ct = gc->chip_types;
 	struct bcm7120_l2_intc_data *b = gc->private;
 
 	irq_gc_lock(gc);
@@ -94,10 +93,9 @@ static void bcm7120_l2_intc_suspend(struct irq_data *d)
 	irq_gc_unlock(gc);
 }
 
-static void bcm7120_l2_intc_resume(struct irq_data *d)
+static void bcm7120_l2_intc_resume(struct irq_chip_generic *gc)
 {
-	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
-	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+	struct irq_chip_type *ct = gc->chip_types;
 
 	/* Restore the saved mask */
 	irq_gc_lock(gc);
@@ -281,8 +279,15 @@ int __init bcm7120_l2_intc_probe(struct device_node *dn,
 		ct->chip.irq_mask = irq_gc_mask_clr_bit;
 		ct->chip.irq_unmask = irq_gc_mask_set_bit;
 		ct->chip.irq_ack = irq_gc_noop;
-		ct->chip.irq_suspend = bcm7120_l2_intc_suspend;
-		ct->chip.irq_resume = bcm7120_l2_intc_resume;
+		ct->chip.chip_suspend = bcm7120_l2_intc_suspend;
+		ct->chip.chip_resume = bcm7120_l2_intc_resume;
+
+		/*
+		 * Initialize mask-cache, in case we need it for
+		 * saving/restoring fwd mask even w/o any child interrupts
+		 * installed
+		 */
+		gc->mask_cache = irq_reg_readl(gc, ct->regs.mask);
 
 		if (data->can_wake) {
 			/* This IRQ chip can wake the system, set all
-- 
1.9.1