PM: Introduce functions for suspending and resuming device interrupts

Introduce helper functions allowing us to prevent device drivers from
getting any interrupts (without disabling interrupts on the CPU)
during suspend (or hibernation) and to make them start to receive
interrupts again during the subsequent resume.  These functions make it
possible to keep timer interrupts enabled while the "late" suspend and
"early" resume callbacks provided by device drivers are being
executed.  In turn, this allows device drivers' "late" suspend and
"early" resume callbacks to sleep, execute ACPI callbacks etc.

The functions introduced here will be used to rework the handling of
interrupts during suspend (hibernation) and resume.  Namely,
interrupts will only be disabled on the CPU right before suspending
sysdevs, while device drivers will be prevented from receiving
interrupts, with the help of the new helper function, before their
"late" suspend callbacks run (and analogously during resume).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 0c9cb63e6895..c68bffd182bb 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -117,6 +117,15 @@ extern void disable_irq_nosync(unsigned int irq);
 extern void disable_irq(unsigned int irq);
 extern void enable_irq(unsigned int irq);
 
+/* The following three functions are for the core kernel use only. */
+extern void suspend_device_irqs(void);
+extern void resume_device_irqs(void);
+#ifdef CONFIG_PM_SLEEP
+extern int check_wakeup_irqs(void);
+#else
+static inline int check_wakeup_irqs(void) { return 0; }
+#endif
+
 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
 
 extern cpumask_var_t irq_default_affinity;
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 9c62fbe2ef30..974890b3c52f 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -67,6 +67,7 @@ typedef	void (*irq_flow_handler_t)(unsigned int irq,
 #define IRQ_SPURIOUS_DISABLED   0x00800000      /* IRQ was disabled by the spurious trap */
 #define IRQ_MOVE_PCNTXT         0x01000000      /* IRQ migration from process context */
 #define IRQ_AFFINITY_SET        0x02000000      /* IRQ affinity was set from userspace*/
+#define IRQ_SUSPENDED           0x04000000      /* IRQ has gone through suspend sequence */
 
 #ifdef CONFIG_IRQ_PER_CPU
 # define CHECK_IRQ_PER_CPU(var) ((var) & IRQ_PER_CPU)