genirq: Add runtime power management support for IRQ chips

Some IRQ chips may be located in a power domain outside of the CPU
subsystem and hence will require device specific runtime power
management. In order to support such IRQ chips, add a pointer for a
device structure to the irq_chip structure, and if this pointer is
populated by the IRQ chip driver and CONFIG_PM is selected in the kernel
configuration, then the pm_runtime_get/put APIs for this chip will be
called when an IRQ is requested/freed, respectively.

Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 2f9f2b0e79f2..ad8131473774 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -1093,3 +1093,43 @@ int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 
         return 0;
 }
+
+/**
+ * irq_chip_pm_get - Enable power for an IRQ chip
+ * @data:       Pointer to interrupt specific data
+ *
+ * Enable the power to the IRQ chip referenced by the interrupt data
+ * structure.
+ */
+int irq_chip_pm_get(struct irq_data *data)
+{
+        int retval;
+
+        if (IS_ENABLED(CONFIG_PM) && data->chip->parent_device) {
+                retval = pm_runtime_get_sync(data->chip->parent_device);
+                if (retval < 0) {
+                        pm_runtime_put_noidle(data->chip->parent_device);
+                        return retval;
+                }
+        }
+
+        return 0;
+}
+
+/**
+ * irq_chip_pm_put - Disable power for an IRQ chip
+ * @data:       Pointer to interrupt specific data
+ *
+ * Disable the power to the IRQ chip referenced by the interrupt data
+ * structure, belongs. Note that power will only be disabled, once this
+ * function has been called for all IRQs that have called irq_chip_pm_get().
+ */
+int irq_chip_pm_put(struct irq_data *data)
+{
+        int retval = 0;
+
+        if (IS_ENABLED(CONFIG_PM) && data->chip->parent_device)
+                retval = pm_runtime_put(data->chip->parent_device);
+
+        return (retval < 0) ? retval : 0;
+}