[PATCH V3 08/17] genirq: Add runtime power management support for IRQ chips

Jon Hunter
2016-05-04T16:26:26Z

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.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
---
include/linux/irq.h | 4 ++++
kernel/irq/chip.c | 35 +++++++++++++++++++++++++++++++++++
kernel/irq/internals.h | 1 +
kernel/irq/manage.c | 31 ++++++++++++++++++++++++++++++-
4 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index c4de62348ff2..a2140d9fa188 100644
--- 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 2f9f2b0e79f2..b09226e895c7 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -1093,3 +1093,38 @@ 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 = 0;
+
+ if (IS_ENABLED(CONFIG_PM) && data->chip->parent_device)
+ retval = pm_runtime_get_sync(data->chip->parent_device);
+
+ return (retval < 0) ? retval : 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 09be2c903c6d..d5edcdc9382a 100644
--- 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 eaedeb74b49d..f8fd1fbc02ea 100644
--- 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);
}
@@ -1829,6 +1843,7 @@ 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;

@@ -1891,10 +1906,18 @@ 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;
}

@@ -1938,12 +1961,18 @@ 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;
}
--
2.1.4