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powerpc/mpic: Remove WHOAMI readback after EOI 

After previous discussions regarding the subject [1][2], there's no clear
explanation or reason why the call was needed in the first place. The sensible
argument is some sort of synchronization between the CPU and the MPIC, which
hasn't been pointed out precisely and is no longer required (at least on BookE
platforms).

The benefit of this change is saving a MMIO trap per interrupt when running in a
KVM guest.

[1] https://patchwork.ozlabs.org/patch/429098/
[2] https://patchwork.ozlabs.org/patch/433557/

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
This commit is contained in:
Bogdan Purcareata 2015-03-24 10:43:43 +00:00 committed by Scott Wood
parent 88b7936da3
commit 56302c53d3
1 changed files with 0 additions and 1 deletions
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arch/powerpc/sysdev/mpic.c
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@ -655,7 +655,6 @@ static inline struct mpic * mpic_from_irq_data(struct irq_data *d)
static inline void mpic_eoi(struct mpic *mpic)
{
mpic_cpu_write(MPIC_INFO(CPU_EOI), 0);
(void)mpic_cpu_read(MPIC_INFO(CPU_WHOAMI));
}
/*