On 07/01/15 16:05, Jason Cooper wrote:
> Marc,
>
> On Tue, Dec 09, 2014 at 09:37:26AM +0000, Marc Zyngier wrote:
>> On 08/12/14 22:42, Bjorn Andersson wrote:
>>> On Wed, Dec 3, 2014 at 8:18 AM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote:
>>>> There is a number of cases where a kernel subsystem may want to
>>>> introspect the state of an interrupt at the irqchip level:
>>>>
>>>> - When a peripheral is shared between virtual machines,
>>>> its interrupt state becomes part of the guest's state,
>>>> and must be switched accordingly. KVM on arm/arm64 requires
>>>> this for its guest-visible timer
>>>> - Some GPIO controllers seem to require peeking into the
>>>> interrupt controller they are connected to to report
>>>> their internal state
>>>>
>>>> This seem to be a pattern that is common enough for the core code
>>>> to try and support this without too many horrible hacks. Introduce
>>>> a pair of accessors (irq_get_irqchip_state/irq_set_irqchip_state)
>>>> to retrieve the bits that can be of interest to another subsystem:
>>>> pending, active, and masked.
>>>>
>>>> - irq_get_irqchip_state returns the state of the interrupt according
>>>> to a parameter set to IRQCHIP_STATE_PENDING, IRQCHIP_STATE_ACTIVE,
>>>> IRQCHIP_STATE_MASKED or IRQCHIP_STATE_LINE_LEVEL.
>>>> - irq_set_irqchip_state similarly sets the state of the interrupt.
>>>>
>>>> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
>>>
>>> With the addition of actually assigning err to something useful in the
>>> setter below:
>>>
>>> Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
>>> Tested-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
>>>
>>>> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
>>>
>>> [..]
>>>
>>>> +/**
>>>> + * irq_set_irqchip_state - set the state of a forwarded interrupt.
>>>> + * @irq: Interrupt line that is forwarded to a VM
>>>> + * @which: State to be restored (one of IRQCHIP_STATE_*)
>>>> + * @val: Value corresponding to @which
>>>> + *
>>>> + * This call sets the internal irqchip state of an interrupt,
>>>> + * depending on the value of @which.
>>>> + *
>>>> + * This function should be called with preemption disabled if the
>>>> + * interrupt controller has per-cpu registers.
>>>> + */
>>>> +int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
>>>> + bool val)
>>>> +{
>>>> + struct irq_desc *desc;
>>>> + struct irq_data *data;
>>>> + struct irq_chip *chip;
>>>> + unsigned long flags;
>>>> + int err = -EINVAL;
>>>> +
>>>> + desc = irq_get_desc_buslock(irq, &flags, 0);
>>>> + if (!desc)
>>>> + return err;
>>>> +
>>>> + data = irq_desc_get_irq_data(desc);
>>>> +
>>>> + do {
>>>> + chip = irq_data_get_irq_chip(data);
>>>> + if (chip->irq_set_irqchip_state)
>>>> + break;
>>>> +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
>>>> + data = data->parent_data;
>>>> +#else
>>>> + data = NULL;
>>>> +#endif
>>>> + } while (data);
>>>> +
>>>> + if (data)
>>>> + chip->irq_set_irqchip_state(data, which, val);
>>>
>>> err =
>>
>> Ah, that will teach me to write test code that actually checks the
>> return value! :-)
>>
>> Thanks for the fix and the tags.
>
> Did I miss the new version of this?
I'm rebasing all my stuff at the moment. Expect something later today
(or tomorrow morning worse case).
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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