Re: [Xen-devel] [PATCH v7 1/5] xen/arm: Add support for GIC v3

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2014-07-22 at 11:01 +0100, Julien Grall wrote:
> 
> On 22/07/14 10:48, Vijay Kilari wrote:
> >>> +/*
> >>> + * Additional registers defined in GIC v3.
> >>> + * Common GICD registers are defined in gic.h
> >>> + */
> >>> +
> >>> +#define GICD_STATUSR                 (0x010)
> >>> [...][
> >>> +#define GICV3_GICD_PIDR0             (0x92)
> >>
> >> What is the distinction between variables with GIC[DR]_ prefixes and
> >> those with GICV3_GIC[DR]_ ones?
> >
> > GICV3 is prefixed for indicating that there are values not the addresses.
> > In anycase I will remove GICV3 prefixes and postfix _VAL
> 
> Those value are GICV3 specific. If you drop the prefix we won't know 
> what are their purpose...

I'm not so sure that's the case. We will know it is the value to use for
GICD_PIDR0 for any GIC which includes that register, which is at least
v3 and v4 right now. Calling it V3 is equally misleading as leaving it
out.

Given that we've decided to share the #defines across versions I think
we should leave the prefix off. The alternative is to make sure
everything is prefixed and to duplicate the definitions for each
version, which is an approach we previously moved away from I think, I
don't see a strong reason to go back on that decision now.

Ian.


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