[RFC PATCH 2/3] genirq: add helper functions to deal with wakeup on shared IRQF_NO_SUSPEND IRQs

[Boris Brezillon]

Add two helper functions to help drivers that are sharing IRQs with
timer devices (or other devices setting the IRQF_NO_SUSPEND flag) deal
with system wakeup and state detection.

Such drivers should expect their IRQ handler to be called in 2 different
contexts:
1/ the system is resumed and the handler should act normally
2/ the system is suspended and the handler should wake it up, and
   potentially save the received events so that they could be taken care
   of when the resume callback is called

irq_is_wakeup_armed provides mean to test the current state (true means
the system is suspended).

irq_pm_force_wakeup provides mean to force a system wakeup.

Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
---
 include/linux/interrupt.h |  3 +++
 kernel/irq/manage.c       | 16 ++++++++++++++++
 kernel/irq/pm.c           |  6 ++++++
 3 files changed, 25 insertions(+)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index d9b05b5..052a3b2 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -356,6 +356,9 @@ static inline int disable_irq_wake(unsigned int irq)
 	return irq_set_irq_wake(irq, 0);
 }
 
+bool irq_is_wakeup_armed(unsigned int irq);
+
+void irq_pm_force_wakeup(void);
 
 #ifdef CONFIG_IRQ_FORCED_THREADING
 extern bool force_irqthreads;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 196a06f..5424be0 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -551,6 +551,22 @@ int irq_set_irq_wake(unsigned int irq, unsigned int on)
 }
 EXPORT_SYMBOL(irq_set_irq_wake);
 
+bool irq_is_wakeup_armed(unsigned int irq)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+	bool ret;
+
+	if (!desc)
+		return false;
+
+	ret = irqd_is_wakeup_armed(&desc->irq_data);
+
+	irq_put_desc_busunlock(desc, flags);
+	return ret;
+}
+EXPORT_SYMBOL(irq_is_wakeup_armed);
+
 /*
  * Internal function that tells the architecture code whether a
  * particular irq has been exclusively allocated or is available
diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c
index 1743162..1110a37 100644
--- a/kernel/irq/pm.c
+++ b/kernel/irq/pm.c
@@ -28,6 +28,12 @@ bool irq_pm_check_wakeup(struct irq_desc *desc)
 	return false;
 }
 
+void irq_pm_force_wakeup(void)
+{
+	pm_system_wakeup();
+}
+EXPORT_SYMBOL_GPL(irq_pm_force_wakeup);
+
 /*
  * Called from __setup_irq() with desc->lock held after @action has
  * been installed in the action chain.
-- 
1.9.1