Re: [PATCH v4 1/3] genirq: Allow the irqchip state of an IRQ to be save/restored
From: Bjorn Andersson
Date: Wed Apr 08 2015 - 13:48:55 EST
On Wed, Mar 18, 2015 at 4:01 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.
> Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
> Tested-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Sorry for bothering you Thomas, but we have a couple of driver for the
Qualcomm platforms that depends on this patch (the line level part).
Could you please have a look at it?
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