Re: [Xen-devel] [PATCH 03 of 10] arm: Move some GIC distributor init out of the per-CPU init function

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2012-02-27 at 19:30 +0000, Tim Deegan wrote:
> At 17:32 +0000 on 27 Feb (1330363933), Ian Campbell wrote:
> > On Thu, 2012-02-23 at 17:40 +0000, Tim Deegan wrote:
> > > # HG changeset patch
> > > # User Tim Deegan <tim@xxxxxxx>
> > > # Date 1330018799 0
> > > # Node ID 437ad1207a175c9ad376871f3f4c075dbcd5b6e6
> > > # Parent  ec051056db2b6d37344629e2f01d17240099d5ec
> > > arm: Move some GIC distributor init out of the per-CPU init function
> > > 
> > > Signed-off-by: Tim Deegan <tim@xxxxxxx>
> > > 
> > > diff -r ec051056db2b -r 437ad1207a17 xen/arch/arm/gic.c
> > > --- a/xen/arch/arm/gic.c  Thu Feb 23 17:39:59 2012 +0000
> > > +++ b/xen/arch/arm/gic.c  Thu Feb 23 17:39:59 2012 +0000
> > > @@ -216,14 +216,6 @@ static void __init gic_dist_init(void)
> > >      for ( i = 32; i < gic.lines; i += 32 )
> > >          GICD[GICD_ICENABLER + i / 32] = ~0ul;
> > >  
> > > -    /* Turn on the distributor */
> > > -    GICD[GICD_CTLR] = GICD_CTL_ENABLE;
> > > -}
> > > -
> > > -static void __cpuinit gic_cpu_init(void)
> > > -{
> > > -    int i;
> > > -
> > >      /* Disable all PPI and enable all SGI */
> > >      GICD[GICD_ICENABLER] = 0xffff0000; /* Disable all PPI */
> > >      GICD[GICD_ISENABLER] = 0x0000ffff; /* Enable all SGI */
> > 
> > PPIs and SGIs are per physical-CPU and therefore, I think, the GICD
> > registers of various sorts which refer to the first 32 interrupts are
> > per physical-CPU as well. IOW moving these from gic_cpu_init to
> > gic_dist_init is wrong?
> 
> Yep, you're right ISENABLER0 and ICENABLER0 are banked.

BTW so are GICD_IPRIORITYR0..4 which are initialised just outside the
context here. More generally all the per-IRQ registers are banked for
the first few which cover the PPIs and SGIs.

>  I'll replace this with a comment explaining that.

Thanks.



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