[RFC PATCH V2 3/8] genirq: Add runtime power management support for IRQ chips

From: Jon Hunter
Date: Thu Dec 17 2015 - 05:51:51 EST


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 the flag CHIP_HAS_RPM is set, 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@xxxxxxxxxx>
---
include/linux/irq.h | 4 ++++
kernel/irq/internals.h | 24 ++++++++++++++++++++++++
kernel/irq/manage.c | 7 +++++++
3 files changed, 35 insertions(+)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 3c1c96786248..7a61a7f76177 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -307,6 +307,7 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
/**
* struct irq_chip - hardware interrupt chip descriptor
*
+ * @dev: pointer to associated device
* @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)
@@ -344,6 +345,7 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
* @flags: chip specific flags
*/
struct irq_chip {
+ struct device *dev;
const char *name;
unsigned int (*irq_startup)(struct irq_data *data);
void (*irq_shutdown)(struct irq_data *data);
@@ -399,6 +401,7 @@ struct irq_chip {
* IRQCHIP_SKIP_SET_WAKE: Skip chip.irq_set_wake(), for this irq chip
* IRQCHIP_ONESHOT_SAFE: One shot does not require mask/unmask
* IRQCHIP_EOI_THREADED: Chip requires eoi() on unmask in threaded mode
+ * IRQCHIP_HAS_PM: Chip requires runtime power management
*/
enum {
IRQCHIP_SET_TYPE_MASKED = (1 << 0),
@@ -408,6 +411,7 @@ enum {
IRQCHIP_SKIP_SET_WAKE = (1 << 4),
IRQCHIP_ONESHOT_SAFE = (1 << 5),
IRQCHIP_EOI_THREADED = (1 << 6),
+ IRQCHIP_HAS_RPM = (1 << 7),
};

#include <linux/irqdesc.h>
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index fcab63c66905..30a2add7cae6 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)
@@ -125,6 +126,29 @@ static inline void chip_bus_sync_unlock(struct irq_desc *desc)
desc->irq_data.chip->irq_bus_sync_unlock(&desc->irq_data);
}

+/* Inline functions for support of irq chips that require runtime pm */
+static inline int chip_pm_get(struct irq_desc *desc)
+{
+ int retval = 0;
+
+ if (desc->irq_data.chip->dev &&
+ desc->irq_data.chip->flags & IRQCHIP_HAS_RPM)
+ retval = pm_runtime_get_sync(desc->irq_data.chip->dev);
+
+ return (retval < 0) ? retval : 0;
+}
+
+static inline int chip_pm_put(struct irq_desc *desc)
+{
+ int retval = 0;
+
+ if (desc->irq_data.chip->dev &&
+ desc->irq_data.chip->flags & IRQCHIP_HAS_RPM)
+ retval = pm_runtime_put(desc->irq_data.chip->dev);
+
+ return (retval < 0) ? retval : 0;
+}
+
#define _IRQ_DESC_CHECK (1 << 0)
#define _IRQ_DESC_PERCPU (1 << 1)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 2a429b061171..8a96e4f1e985 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1116,6 +1116,10 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
if (!try_module_get(desc->owner))
return -ENODEV;

+ ret = chip_pm_get(desc);
+ if (ret < 0)
+ return ret;
+
new->irq = irq;

/*
@@ -1400,6 +1404,7 @@ out_thread:
put_task_struct(t);
}
out_mput:
+ chip_pm_put(desc);
module_put(desc->owner);
return ret;
}
@@ -1513,6 +1518,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
}
}

+ chip_pm_put(desc);
module_put(desc->owner);
kfree(action->secondary);
return action;
@@ -1799,6 +1805,7 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_

unregister_handler_proc(irq, action);

+ chip_pm_put(desc);
module_put(desc->owner);
return action;

--
2.1.4

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