On 06/06/2016 05:30 PM, Jon Hunter wrote:
>
> On 06/06/16 15:13, Grygorii Strashko wrote:
>> On 06/06/2016 02:53 PM, Jon Hunter wrote:
>>> 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@xxxxxxxxxx>
>>> Reviewed-by: Kevin Hilman <khilman@xxxxxxxxxxxx>
>>> Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx>
>>> ---
>>> 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).
--
regards,
-grygorii
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