GIC: implement suspend and resume

While in suspend state, the system should not wake up due to triggering
of a non wakeup interrupt. Implement suspend and resume functions to be
called from power management code to switch enabled interrupts between
wakeup set or normal set.

Change-Id: Iaceae286707460eadc5f05c0baef72b43c942777
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>

1 files changed, 88 insertions, 0 deletions

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 10b73d9bea78..2ca62ef5ff36 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -41,6 +41,7 @@
 #include <linux/irqchip.h>
 #include <linux/irqchip/chained_irq.h>
 #include <linux/irqchip/arm-gic.h>
+#include <linux/syscore_ops.h>
 
 #include <asm/cputype.h>
 #include <asm/irq.h>
@@ -69,6 +70,7 @@ union gic_base {
 };
 
 struct gic_chip_data {
+	unsigned int irq_offset;
 	union gic_base dist_base;
 	union gic_base cpu_base;
 #ifdef CONFIG_CPU_PM
@@ -85,6 +87,10 @@ struct gic_chip_data {
 #ifdef CONFIG_GIC_NON_BANKED
 	void __iomem *(*get_base)(union gic_base *);
 #endif
+#ifdef CONFIG_PM
+	unsigned int wakeup_irqs[32];
+	unsigned int enabled_irqs[32];
+#endif
 };
 
 static DEFINE_RAW_SPINLOCK(irq_controller_lock);
@@ -222,6 +228,74 @@ static void gic_unmask_irq(struct irq_data *d)
 	raw_spin_unlock_irqrestore(&irq_controller_lock, flags);
 }
 
+#ifdef CONFIG_PM
+static int gic_suspend_one(struct gic_chip_data *gic)
+{
+	unsigned int i;
+	void __iomem *base = gic_data_dist_base(gic);
+
+	for (i = 0; i * 32 < gic->gic_irqs; i++) {
+		gic->enabled_irqs[i]
+			= readl_relaxed(base + GIC_DIST_ENABLE_SET + i * 4);
+		/* disable all of them */
+		writel_relaxed(0xffffffff,
+			base + GIC_DIST_ENABLE_CLEAR + i * 4);
+		/* enable the wakeup set */
+		writel_relaxed(gic->wakeup_irqs[i],
+			base + GIC_DIST_ENABLE_SET + i * 4);
+	}
+	/* make sure all gic setting finished */
+	mb();
+	return 0;
+}
+
+static int gic_suspend(void)
+{
+	int i;
+
+	for (i = 0; i < MAX_GIC_NR; i++)
+		gic_suspend_one(&gic_data[i]);
+	return 0;
+}
+
+static void gic_resume_one(struct gic_chip_data *gic)
+{
+	unsigned int i;
+	void __iomem *base = gic_data_dist_base(gic);
+
+	for (i = 0; i * 32 < gic->gic_irqs; i++) {
+		/* disable all of them */
+		writel_relaxed(0xffffffff,
+			base + GIC_DIST_ENABLE_CLEAR + i * 4);
+		/* enable the enabled set */
+		writel_relaxed(gic->enabled_irqs[i],
+			base + GIC_DIST_ENABLE_SET + i * 4);
+	}
+	/* make sure all gic setting finished */
+	mb();
+}
+
+static void gic_resume(void)
+{
+	int i;
+
+	for (i = 0; i < MAX_GIC_NR; i++)
+		gic_resume_one(&gic_data[i]);
+}
+
+static struct syscore_ops gic_syscore_ops = {
+	.suspend = gic_suspend,
+	.resume = gic_resume,
+};
+
+static int __init gic_init_sys(void)
+{
+	register_syscore_ops(&gic_syscore_ops);
+	return 0;
+}
+arch_initcall(gic_init_sys);
+#endif
+
 static void gic_eoi_irq(struct irq_data *d)
 {
 	if (gic_arch_extn.irq_eoi) {
@@ -373,6 +447,20 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
 static int gic_set_wake(struct irq_data *d, unsigned int on)
 {
 	int ret = -ENXIO;
+	unsigned int reg_offset, bit_offset;
+	unsigned int gicirq = gic_irq(d);
+	struct gic_chip_data *gic_data = irq_data_get_irq_chip_data(d);
+
+	/* per-cpu interrupts cannot be wakeup interrupts */
+	WARN_ON(gicirq < 32);
+
+	reg_offset = gicirq / 32;
+	bit_offset = gicirq % 32;
+
+	if (on)
+		gic_data->wakeup_irqs[reg_offset] |=  1 << bit_offset;
+	else
+		gic_data->wakeup_irqs[reg_offset] &=  ~(1 << bit_offset);
 
 	if (gic_arch_extn.irq_set_wake)
 		ret = gic_arch_extn.irq_set_wake(d, on);