Re: [PATCH v4] ARM: cache-l2x0.c: save aux ctrl for resume in casel2x0 is enabled before init

[Yilu Mao]

On 04/30/2012 09:34 PM, Catalin Marinas wrote:
> On 30 April 2012 14:16, Yilu Mao<ylmao@xxxxxxxxxxx>  wrote:
> > If l2x0 controller has been enabled when calling l2x0_init, the aux ctrl
> > register will not be saved in l2x0_saved_regs. Therefore we can not use
> > l2x0_saved_regs.aux_ctrl for resume later. This patch fixed the problem
> > by saving aux ctrl in l2x0_saved_regs just after it's being read from
> > the register.
> > And in case some bits of aux ctrl register are reserved, re-read and
> > save it properly after set it if l2x0 is disabled before init.
> >
> > Change-Id: I54f3002274ffe9cdc667dba81e36e08f2e121467
> > Signed-off-by: Yilu Mao<ylmao@xxxxxxxxxxx>
> > ---
> >   arch/arm/mm/cache-l2x0.c |    9 +++++++++
> >   1 files changed, 9 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
> > index a53fd2a..9893e58 100644
> > --- a/arch/arm/mm/cache-l2x0.c
> > +++ b/arch/arm/mm/cache-l2x0.c
> > @@ -320,6 +320,13 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
> >         cache_id = readl_relaxed(l2x0_base + L2X0_CACHE_ID);
> >         aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
> >
> > +       /*
> > +        * In case l2x controller is enabled, the aux ctrl register
> > +        * can't be set. So the original value should be stored in
> > +        * the l2x0_saved_regs for restoring when resume.
> > +        */
> > +       l2x0_saved_regs.aux_ctrl = aux;
>
> Why not move this
>
> > +
> >         aux&= aux_mask;
> >         aux |= aux_val;
> >
> > @@ -364,6 +371,8 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
> >                 /* l2x0 controller is disabled */
> >                 writel_relaxed(aux, l2x0_base + L2X0_AUX_CTRL);
> >
> > +               /* Re-read it in case some bits are reserved. */
> > +               aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
>
> and this
>
> >                 l2x0_saved_regs.aux_ctrl = aux;
> >
> >                 l2x0_inv_all();
>
> somewhere after the if block and we only read the aux once. The
> comment may no longer make sense though.
Hi Catalin,

I want to make it clear before I provide a new patch. :)
We can't only read once because we must read it before handle the 
aux_val and aux_mask arguments.
Do you still want the "l2x0_saved_regs.aux_ctrl = aux;" operation only 
located after the "if"?
If so, I will provide a patch for it.

--
Thanks.

Best Wishes,
Yilu Mao
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