Re: [PATCH 3.17-rc4 v7 4/6] irqchip: gic: Add support for IPI FIQ

[Russell King - ARM Linux]

On Wed, Sep 17, 2014 at 10:07:13PM +0100, Russell King - ARM Linux wrote:
> On Wed, Sep 17, 2014 at 01:12:23PM -0700, Daniel Thompson wrote:
> > I may have missed something but this sounds like the expected behaviour
> > to me.
> > 
> > Without AckCtl set (GIC_CPU_CTRL bit 2) then it is not possible to
> > acknowledge group 1 interrupts from secure mode. Thus in the
> > circumstances described above I would expect the system to wedge in the
> > interrupt handler because IRQ is raised but the software is not able to
> > acknowledge it.
> 
> Setting AckCtl (0x07) results in no change in behaviour - still crashes
> when it tries to calibrate the timer.
> 
> > I think there may also problems with leaving CBPR unset. Leaving CBPR
> > unset certainly causes a change of behaviour compared to an all group0
> > setup.
> 
> Also tried setting that (0x17), but still the same.

Another data point: SDP4430 boots fine with 0x17.

The Versatile Express has GIC ID/TYPER register values of:

GICC IDR: 0x3901043b GICD TYPER: 0x0000fc62

The SDP4430 has:

GICC IDR: 0x3901043b GICD TYPER: 0x0000fc24

so they should in theory be identical GICs, and should behave identically,
but they don't.

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