Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips
From: Marc Zyngier
Date: Thu Mar 17 2016 - 11:28:47 EST
On 17/03/16 15:13, Jon Hunter wrote:
> Hi Marc,
>
> On 17/03/16 15:02, Marc Zyngier wrote:
>> Hi Jon,
>>
>> On 17/03/16 14:19, 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.
>>>
>>> When entering system suspend and each interrupt is disabled if there is
>>> no wake-up set for that interrupt. For an IRQ chip that utilises runtime
>>> power management, print a warning message for each active interrupt that
>>> has no wake-up set because these interrupts may be unnecessarily keeping
>>> the IRQ chip enabled during system suspend.
>>>
>>> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
>>> ---
>>> include/linux/irq.h | 5 +++++
>>> kernel/irq/chip.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>> kernel/irq/internals.h | 1 +
>>> kernel/irq/manage.c | 14 +++++++++++---
>>> kernel/irq/pm.c | 3 +++
>>> 5 files changed, 72 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/include/linux/irq.h b/include/linux/irq.h
>>> index c4de62348ff2..82f36390048d 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: 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)
>>> @@ -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;
>>
>> Nit: Please don't call this just "parent". We have parent fields in
>> irq_data and irq_domain structures, and they always are a pointer to the
>> same type, indicating some form of stacking. Here, we're pointing to a
>> different type altogether...
>>
>> How about calling it "dev", or "device" instead? It would make it much
>> clearer that when crossing that pointer, we're in another subsystem
>> altogether.
>
> I will defer to Linus W here, as it was his request we make this
> 'parent' and not 'dev'. See ...
>
> http://marc.info/?l=linux-kernel&m=145035839623442&w=2
Well, that contradicts the way use use the word "parent" in the IRQ
subsystem, I guess. I'd settle for parent_device or something along
those lines (but keep in mind I'm really bad at naming things).
Anyway, enough bikeshedding... ;-)
M.
--
Jazz is not dead. It just smells funny...