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>

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 4d758a7..6c92a84 100644 (file)
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -315,6 +315,7 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
 /**
  * struct irq_chip - hardware interrupt chip descriptor
  *
+ * @parent_device:     pointer to parent device for irqchip
  * @name:              name for /proc/interrupts
  * @irq_startup:       start up the interrupt (defaults to ->enable if NULL)
  * @irq_shutdown:      shut down the interrupt (defaults to ->disable if NULL)
@@ -354,6 +355,7 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
  * @flags:             chip specific flags
  */
 struct irq_chip {
+       struct device   *parent_device;
        const char      *name;
        unsigned int    (*irq_startup)(struct irq_data *data);
        void            (*irq_shutdown)(struct irq_data *data);
@@ -488,6 +490,8 @@ extern void handle_bad_irq(struct irq_desc *desc);
 extern void handle_nested_irq(unsigned int irq);
 
 extern int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg);
+extern int irq_chip_pm_get(struct irq_data *data);
+extern int irq_chip_pm_put(struct irq_data *data);
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
 extern void irq_chip_enable_parent(struct irq_data *data);
 extern void irq_chip_disable_parent(struct irq_data *data);

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 2f9f2b0..ad81314 100644 (file)
--- 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;
+}

diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 09be2c9..d5edcdc 100644 (file)
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -7,6 +7,7 @@
  */
 #include <linux/irqdesc.h>
 #include <linux/kernel_stat.h>
+#include <linux/pm_runtime.h>
 
 #ifdef CONFIG_SPARSE_IRQ
 # define IRQ_BITMAP_BITS       (NR_IRQS + 8196)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index f78b084..00cfc85 100644 (file)
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1416,10 +1416,18 @@ int setup_irq(unsigned int irq, struct irqaction *act)
 
        if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
                return -EINVAL;
+
+       retval = irq_chip_pm_get(&desc->irq_data);
+       if (retval < 0)
+               return retval;
+
        chip_bus_lock(desc);
        retval = __setup_irq(irq, desc, act);
        chip_bus_sync_unlock(desc);
 
+       if (retval)
+               irq_chip_pm_put(&desc->irq_data);
+
        return retval;
 }
 EXPORT_SYMBOL_GPL(setup_irq);
@@ -1513,6 +1521,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
                }
        }
 
+       irq_chip_pm_put(&desc->irq_data);
        module_put(desc->owner);
        kfree(action->secondary);
        return action;
@@ -1655,11 +1664,16 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler,
        action->name = devname;
        action->dev_id = dev_id;
 
+       retval = irq_chip_pm_get(&desc->irq_data);
+       if (retval < 0)
+               return retval;
+
        chip_bus_lock(desc);
        retval = __setup_irq(irq, desc, action);
        chip_bus_sync_unlock(desc);
 
        if (retval) {
+               irq_chip_pm_put(&desc->irq_data);
                kfree(action->secondary);
                kfree(action);
        }
@@ -1836,6 +1850,7 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_
 
        unregister_handler_proc(irq, action);
 
+       irq_chip_pm_put(&desc->irq_data);
        module_put(desc->owner);
        return action;
 
@@ -1898,10 +1913,18 @@ int setup_percpu_irq(unsigned int irq, struct irqaction *act)
 
        if (!desc || !irq_settings_is_per_cpu_devid(desc))
                return -EINVAL;
+
+       retval = irq_chip_pm_get(&desc->irq_data);
+       if (retval < 0)
+               return retval;
+
        chip_bus_lock(desc);
        retval = __setup_irq(irq, desc, act);
        chip_bus_sync_unlock(desc);
 
+       if (retval)
+               irq_chip_pm_put(&desc->irq_data);
+
        return retval;
 }
 
@@ -1945,12 +1968,18 @@ int request_percpu_irq(unsigned int irq, irq_handler_t handler,
        action->name = devname;
        action->percpu_dev_id = dev_id;
 
+       retval = irq_chip_pm_get(&desc->irq_data);
+       if (retval < 0)
+               return retval;
+
        chip_bus_lock(desc);
        retval = __setup_irq(irq, desc, action);
        chip_bus_sync_unlock(desc);
 
-       if (retval)
+       if (retval) {
+               irq_chip_pm_put(&desc->irq_data);
                kfree(action);
+       }
 
        return retval;
 }