On 06/06/16 15:36, Grygorii Strashko wrote:

quoted

On 06/06/2016 05:30 PM, Jon Hunter wrote:

quoted

On 06/06/16 15:13, Grygorii Strashko wrote:

quoted

On 06/06/2016 02:53 PM, Jon Hunter wrote:

quoted

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 <redacted>
Reviewed-by: Kevin Hilman <khilman-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
Reviewed-by: Marc Zyngier <redacted>
---
   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 4d758a7c604a..6c92a847394d 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);

Sry, for the late comment - above require pm_runtime_put_noidle(data->chip->parent_device);
in case of failure.

No problem. Sorry, can you elaborate? I am not familiar with the
_put_noidle().

Question here in use counter - pm_runtime_get_sync() will increment usage_count
always and it will not decrement it in case of failure.
pm_runtime_put_noidle() expected to restore usage_count state (-1).

Thanks was not aware of that. 

Kevin, Marc, given that you have reviewed this one, are you ok with the
above change Grygorii is proposing? 

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index b09226e895c7..63f1860acc4c 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c

@@ -1105,8 +1105,11 @@ int irq_chip_pm_get(struct irq_data *data)
 {
        int retval = 0;
 
-       if (IS_ENABLED(CONFIG_PM) && data->chip->parent_device)
+       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 < 0) ? retval : 0;
 }