[RFC PATCH v2 3/5] ARM: kernel: update cpu_suspend code to use cache LoUIS operations

[Guennadi Liakhovetski]

Hi Will

On Wed, 12 Dec 2012, Will Deacon wrote:

> On Tue, Dec 11, 2012 at 11:27:39PM +0000, Stephen Boyd wrote:
> > On 12/11/12 08:38, Will Deacon wrote:
> > > diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
> > > index cd95664..f58248f 100644
> > > --- a/arch/arm/mm/cache-v7.S
> > > +++ b/arch/arm/mm/cache-v7.S
> > > @@ -44,7 +44,8 @@ ENDPROC(v7_flush_icache_all)
> > >  ENTRY(v7_flush_dcache_louis)
> > >         dmb                                     @ ensure ordering with previous memory accesses
> > >         mrc     p15, 1, r0, c0, c0, 1           @ read clidr, r0 = clidr
> > > -       ands    r3, r0, #0xe00000               @ extract LoUIS from clidr
> > > +       ALT_SMP(ands    r3, r0, #(7 << 21))     @ extract LoUIS from clidr
> > > +       ALT_UP(ands     r3, r0, #(7 << 27))     @ extract LoUU from clidr
> > >         mov     r3, r3, lsr #20                 @ r3 = LoUIS * 2
> > 
> > You need to fix this mov as well, right?
> 
> Ha, nice catch. So the original patch ended up with a ridiculously high
> level number and would've flushed L2, hence we will need to retest with the
> fix below...

Had to apply manually, but it worked too.

Thanks
Guennadi

> 
> Will
> 
> --->8
> 
> diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
> index cd95664..7539ec2 100644
> --- a/arch/arm/mm/cache-v7.S
> +++ b/arch/arm/mm/cache-v7.S
> @@ -44,8 +44,10 @@ ENDPROC(v7_flush_icache_all)
>  ENTRY(v7_flush_dcache_louis)
>         dmb                                     @ ensure ordering with previous memory accesses
>         mrc     p15, 1, r0, c0, c0, 1           @ read clidr, r0 = clidr
> -       ands    r3, r0, #0xe00000               @ extract LoUIS from clidr
> -       mov     r3, r3, lsr #20                 @ r3 = LoUIS * 2
> +       ALT_SMP(ands    r3, r0, #(7 << 21))     @ extract LoUIS from clidr
> +       ALT_UP(ands     r3, r0, #(7 << 27))     @ extract LoUU from clidr
> +       ALT_SMP(mov     r3, r3, lsr #20)        @ r3 = LoUIS * 2
> +       ALT_UP(mov      r3, r3, lsr #26)        @ r3 = LoUU * 2
>         moveq   pc, lr                          @ return if level == 0
>         mov     r10, #0                         @ r10 (starting level) = 0
>         b       flush_levels                    @ start flushing cache levels
> 

---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/