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Date: Mon, 6 Jun 2016 16:06:34 +0100
From: Jon Hunter <jonathanh@...dia.com>
To: Grygorii Strashko <grygorii.strashko@...com>,
Thomas Gleixner <tglx@...utronix.de>,
Jason Cooper <jason@...edaemon.net>,
Marc Zyngier <marc.zyngier@....com>,
Kevin Hilman <khilman@...nel.org>
CC: Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
"Mark Rutland" <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Stephen Warren <swarren@...dotorg.org>,
Thierry Reding <thierry.reding@...il.com>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Lars-Peter Clausen <lars@...afoo.de>,
Linus Walleij <linus.walleij@...aro.org>,
<linux-tegra@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V5 4/9] genirq: Add runtime power management support for
IRQ chips
On 06/06/16 15:36, Grygorii Strashko wrote:
> 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@...dia.com>
>>>> Reviewed-by: Kevin Hilman <khilman@...libre.com>
>>>> Reviewed-by: Marc Zyngier <marc.zyngier@....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 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;
}
Cheers
Jon
--
nvpublic
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