[PATCH V2] Report interrupt(s) that caused system wakeup

@@ -256,3 +256,14 @@ Description:
 		Writing a "1" enables this printing while writing a "0"
 		disables it.  The default value is "0".  Reading from this file
 		will display the current value.
+
+What:		/sys/power/pm_last_wakeup_irqs
+Date:		April 2015
+Contact:	Alexandra Yates <alexandra.yates@linux.intel.org>
+Description:
+		The /sys/power/pm_last_wakeup_irqs file allows user space
+		to identify and report the IRQs responsible from waking the
+		system up from sleep. The IRQD_WAKEUP_TRIGGERED flag is set and
+		reported when the given IRQ fires after it has been armed for
+		system wakeup. This output is useful for system wakeup
+		diagnostics.

@@ -737,6 +737,33 @@ void pm_wakeup_clear(void)
 	pm_abort_suspend = false;
 }
 
+#ifdef CONFIG_PM_SLEEP_DEBUG
+/*
+ * pm_get_last_wakeup_irqs - Parses interrupts to identify which one
+ * caused the system to wake up from suspend-to-idle.
+ * @buf: keeps track of the irqs that casued the system to wakeup
+ */
+ssize_t pm_get_last_wakeup_irqs(char *buf, size_t size)
+{
+	struct irq_desc *desc;
+	int irq;
+	char *str = buf;
+	char *end = buf + size;
+
+	if (pm_abort_suspend) {
+		for_each_irq_desc(irq, desc)
+			if (irqd_triggered_wakeup(&desc->irq_data))
+				str += scnprintf(str, end - str, "%d ", irq);
+
+		if (str != buf)
+			str--;
+
+		return (str - buf);
+	}
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP_DEBUG */
+
 /**
  * pm_get_wakeup_count - Read the number of registered wakeup events.
  * @count: Address to store the value at.

@@ -182,6 +182,7 @@ struct irq_data {
  * IRQD_IRQ_MASKED		- Masked state of the interrupt
  * IRQD_IRQ_INPROGRESS		- In progress state of the interrupt
  * IRQD_WAKEUP_ARMED		- Wakeup mode armed
+ * IRQD_WAKEUP_TRIGGERED	- Triggered system wakeup
  */
 enum {
 	IRQD_TRIGGER_MASK		= 0xf,

@@ -196,8 +197,16 @@ enum {
 	IRQD_IRQ_MASKED			= (1 << 17),
 	IRQD_IRQ_INPROGRESS		= (1 << 18),
 	IRQD_WAKEUP_ARMED		= (1 << 19),
+	IRQD_WAKEUP_TRIGGERED		= (1 << 20),
 };
 
+#ifdef CONFIG_PM_SLEEP_DEBUG
+static inline bool irqd_triggered_wakeup(struct irq_data *d)
+{
+	return d->state_use_accessors & IRQD_WAKEUP_TRIGGERED;
+}
+#endif
+
 static inline bool irqd_is_setaffinity_pending(struct irq_data *d)
 {
 	return d->state_use_accessors & IRQD_SETAFFINITY_PENDING;

@@ -378,6 +378,7 @@ void restore_processor_state(void);
 /* kernel/power/main.c */
 extern int register_pm_notifier(struct notifier_block *nb);
 extern int unregister_pm_notifier(struct notifier_block *nb);
+extern ssize_t pm_get_last_wakeup_irqs(char *buf, size_t size);
 
 #define pm_notifier(fn, pri) {				\
 	static struct notifier_block fn##_nb =			\

@@ -22,6 +22,9 @@ bool irq_pm_check_wakeup(struct irq_desc *desc)
 		desc->depth++;
 		irq_disable(desc);
 		pm_system_wakeup();
+#ifdef CONFIG_PM_SLEEP_DEBUG
+		irqd_set(&desc->irq_data, IRQD_WAKEUP_TRIGGERED);i
+#endif
 		return true;
 	}
 	return false;

@@ -73,6 +76,9 @@ static bool suspend_device_irq(struct irq_desc *desc, int irq)
 	if (!desc->action || desc->no_suspend_depth)
 		return false;
 
+#ifdef CONFIG_PM_SLEEP_DEBUG
+	irqd_clear(&desc->irq_data, IRQD_WAKEUP_TRIGGERED);
+#endif
 	if (irqd_is_wakeup_set(&desc->irq_data)) {
 		irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
 		/*

@@ -272,6 +272,28 @@ static inline void pm_print_times_init(void)
 {
 	pm_print_times_enabled = !!initcall_debug;
 }
+
+static ssize_t pm_last_wakeup_irqs_show(struct kobject *kobj,
+					struct kobj_attribute *attr,
+					char *buf)
+{
+	size_t ret;
+
+	ret = pm_get_last_wakeup_irqs(buf, PAGE_SIZE);
+	if (ret)
+		buf[ret++] = '\n';
+
+	return ret;
+}
+
+static ssize_t pm_last_wakeup_irqs_store(struct kobject *kobj,
+					struct kobj_attribute *attr,
+					const char *buf, size_t n)
+{
+	return -EINVAL;
+}
+power_attr(pm_last_wakeup_irqs);
+
 #else /* !CONFIG_PP_SLEEP_DEBUG */
 static inline void pm_print_times_init(void) {}
 #endif /* CONFIG_PM_SLEEP_DEBUG */

@@ -604,6 +626,7 @@ static struct attribute * g[] = {
 #endif
 #ifdef CONFIG_PM_SLEEP_DEBUG
 	&pm_print_times_attr.attr,
+	&pm_last_wakeup_irqs_attr.attr,
 #endif
 #endif
 #ifdef CONFIG_FREEZER