[PATCH v5 3/6] genirq/PM: Introduce IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND flag

[Maulik Shah <mkshah@xxxxxxxxxxxxxx>]

An interrupt that is disabled/masked but set for wakeup still
needs to be able to wake up the system from sleep states like
"suspend to RAM".

Introduce IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND flag. If this flag
is set wake irqs will get enabled/unmasked on suspend entry by
invoking .irq_enable/.irq_unmask callback of irqchip.

Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Maulik Shah <mkshah@xxxxxxxxxxxxxx>
---
 include/linux/irq.h  | 41 ++++++++++++++++++++++-------------------
 kernel/irq/debugfs.c |  1 +
 kernel/irq/pm.c      |  7 ++++++-
 3 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 1b7f4df..752eb9a 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -545,27 +545,30 @@ struct irq_chip {
 /*
  * irq_chip specific flags
  *
- * IRQCHIP_SET_TYPE_MASKED:	Mask before calling chip.irq_set_type()
- * IRQCHIP_EOI_IF_HANDLED:	Only issue irq_eoi() when irq was handled
- * IRQCHIP_MASK_ON_SUSPEND:	Mask non wake irqs in the suspend path
- * IRQCHIP_ONOFFLINE_ENABLED:	Only call irq_on/off_line callbacks
- *				when irq enabled
- * IRQCHIP_SKIP_SET_WAKE:	Skip chip.irq_set_wake(), for this irq chip
- * IRQCHIP_ONESHOT_SAFE:	One shot does not require mask/unmask
- * IRQCHIP_EOI_THREADED:	Chip requires eoi() on unmask in threaded mode
- * IRQCHIP_SUPPORTS_LEVEL_MSI	Chip can provide two doorbells for Level MSIs
- * IRQCHIP_SUPPORTS_NMI:	Chip can deliver NMIs, only for root irqchips
+ * IRQCHIP_SET_TYPE_MASKED:           Mask before calling chip.irq_set_type()
+ * IRQCHIP_EOI_IF_HANDLED:            Only issue irq_eoi() when irq was handled
+ * IRQCHIP_MASK_ON_SUSPEND:           Mask non wake irqs in the suspend path
+ * IRQCHIP_ONOFFLINE_ENABLED:         Only call irq_on/off_line callbacks
+ *                                    when irq enabled
+ * IRQCHIP_SKIP_SET_WAKE:             Skip chip.irq_set_wake(), for this irq chip
+ * IRQCHIP_ONESHOT_SAFE:              One shot does not require mask/unmask
+ * IRQCHIP_EOI_THREADED:              Chip requires eoi() on unmask in threaded mode
+ * IRQCHIP_SUPPORTS_LEVEL_MSI:        Chip can provide two doorbells for Level MSIs
+ * IRQCHIP_SUPPORTS_NMI:              Chip can deliver NMIs, only for root irqchips
+ * IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND:  Invoke .irq_enable/.irq_unmask for wake irqs
+ *                                    in the suspend path
  */
 enum {
-	IRQCHIP_SET_TYPE_MASKED		= (1 <<  0),
-	IRQCHIP_EOI_IF_HANDLED		= (1 <<  1),
-	IRQCHIP_MASK_ON_SUSPEND		= (1 <<  2),
-	IRQCHIP_ONOFFLINE_ENABLED	= (1 <<  3),
-	IRQCHIP_SKIP_SET_WAKE		= (1 <<  4),
-	IRQCHIP_ONESHOT_SAFE		= (1 <<  5),
-	IRQCHIP_EOI_THREADED		= (1 <<  6),
-	IRQCHIP_SUPPORTS_LEVEL_MSI	= (1 <<  7),
-	IRQCHIP_SUPPORTS_NMI		= (1 <<  8),
+	IRQCHIP_SET_TYPE_MASKED			= (1 <<  0),
+	IRQCHIP_EOI_IF_HANDLED			= (1 <<  1),
+	IRQCHIP_MASK_ON_SUSPEND			= (1 <<  2),
+	IRQCHIP_ONOFFLINE_ENABLED		= (1 <<  3),
+	IRQCHIP_SKIP_SET_WAKE			= (1 <<  4),
+	IRQCHIP_ONESHOT_SAFE			= (1 <<  5),
+	IRQCHIP_EOI_THREADED			= (1 <<  6),
+	IRQCHIP_SUPPORTS_LEVEL_MSI		= (1 <<  7),
+	IRQCHIP_SUPPORTS_NMI			= (1 <<  8),
+	IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND	= (1 <<  9),
 };
 
 #include <linux/irqdesc.h>
diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
index b95ff5d..ab4f637 100644
--- a/kernel/irq/debugfs.c
+++ b/kernel/irq/debugfs.c
@@ -57,6 +57,7 @@ static const struct irq_bit_descr irqchip_flags[] = {
 	BIT_MASK_DESCR(IRQCHIP_EOI_THREADED),
 	BIT_MASK_DESCR(IRQCHIP_SUPPORTS_LEVEL_MSI),
 	BIT_MASK_DESCR(IRQCHIP_SUPPORTS_NMI),
+	BIT_MASK_DESCR(IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND),
 };
 
 static void
diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c
index c6c7e18..2cc800b 100644
--- a/kernel/irq/pm.c
+++ b/kernel/irq/pm.c
@@ -69,12 +69,17 @@ void irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action)
 
 static bool suspend_device_irq(struct irq_desc *desc)
 {
+	unsigned long chipflags = irq_desc_get_chip(desc)->flags;
+
 	if (!desc->action || irq_desc_is_chained(desc) ||
 	    desc->no_suspend_depth)
 		return false;
 
 	if (irqd_is_wakeup_set(&desc->irq_data)) {
 		irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
+
+		if (chipflags & IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND)
+			irq_enable(desc);
 		/*
 		 * We return true here to force the caller to issue
 		 * synchronize_irq(). We need to make sure that the
@@ -93,7 +98,7 @@ static bool suspend_device_irq(struct irq_desc *desc)
 	 * chip level. The chip implementation indicates that with
 	 * IRQCHIP_MASK_ON_SUSPEND.
 	 */
-	if (irq_desc_get_chip(desc)->flags & IRQCHIP_MASK_ON_SUSPEND)
+	if (chipflags & IRQCHIP_MASK_ON_SUSPEND)
 		mask_irq(desc);
 	return true;
 }
-- 
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