[RFC PATCH 1/4] ARM: kernel: Small fixes in save/restore common code.

[Lorenzo Pieralisi]

On Fri, Aug 19, 2011 at 03:33:45PM +0100, Amit Kucheria wrote:
> This patch is redundant with Lorenzo's new series[1]. Adding him to cc. I
> suggest you rebase on top of his latest series.
> 

Yes, thanks for pointing that out.

> On 11 Aug 19, Amit Daniel Kachhap wrote:
> > These changes are necessary to make the retention cpuidle state work. This adds 
> > support for saving more L2 registers.
> > 
> > Signed-off-by: Amit Daniel Kachhap <amit.kachhap at linaro.org>
> > ---
> >  arch/arm/common/gic.c        |    1 -
> >  arch/arm/kernel/sr_helpers.h |    2 +-
> >  arch/arm/mm/cache-l2x0.c     |   10 +++++++++-
> >  3 files changed, 10 insertions(+), 3 deletions(-)
> > 
> > diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
> > index d845b75..124e122 100644
> > --- a/arch/arm/common/gic.c
> > +++ b/arch/arm/common/gic.c
> > @@ -385,7 +385,6 @@ static void gic_dist_save(unsigned int gic_nr)
> >  		gic_data[gic_nr].saved_spi_enable[i] =
> >  			readl_relaxed(dist_base + GIC_DIST_ENABLE_SET + i * 4);
> >  
> > -	writel_relaxed(0, dist_base + GIC_DIST_CTRL);
> >  }
> 
> He already has this bit in his tree[1]
> 
> >  /*
> > diff --git a/arch/arm/kernel/sr_helpers.h b/arch/arm/kernel/sr_helpers.h
> > index 1ae3a9a..5a30461 100644
> > --- a/arch/arm/kernel/sr_helpers.h
> > +++ b/arch/arm/kernel/sr_helpers.h
> > @@ -44,7 +44,7 @@ static inline void exit_coherency(void)
> >  		"mcr	p15, 0, %0, c1, c0, 1\n"
> >  		 : "=&r" (v)
> >  		 : "Ir" (0x40)
> > -		 : );
> > +		 : "cc");
> 
> He has a different fix for this.
> 

We have to rework it anyway it since it does not belong in generic code.

> >  }
> >  #else
> >  static inline void exit_coherency(void) { }
> > diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
> > index 4c99d41..f23696b 100644
> > --- a/arch/arm/mm/cache-l2x0.c
> > +++ b/arch/arm/mm/cache-l2x0.c
> > @@ -285,7 +285,11 @@ static void l2x0_save_context(void *data, bool dormant, unsigned long end)
> >  	*l2x0_regs =  readl_relaxed(l2x0_base + L2X0_TAG_LATENCY_CTRL);
> >  	l2x0_regs++;
> >  	*l2x0_regs =  readl_relaxed(l2x0_base + L2X0_DATA_LATENCY_CTRL);
> > -
> > +	l2x0_regs++;
> > +	*l2x0_regs =  readl_relaxed(l2x0_base + L2X0_PREFETCH_CTRL);
> > +	l2x0_regs++;
> > +	*l2x0_regs =  readl_relaxed(l2x0_base + L2X0_POWER_CTRL);
> > +	dormant = 0;

This is not right, dormant mode depends on cluster state and L2
retention capabilities, it must not be forced. I fixed L2 stack cleaning
when L2 is in retention, please fetch [1] below.

> >  	if (!dormant) {
> >  		/* clean entire L2 before disabling it*/
> >  		writel_relaxed(l2x0_way_mask, l2x0_base + L2X0_CLEAN_WAY);
> > @@ -325,6 +329,10 @@ static void l2x0_restore_context(void *data, bool dormant)
> >  		writel_relaxed(*l2x0_regs, l2x0_base + L2X0_TAG_LATENCY_CTRL);
> >  		l2x0_regs++;
> >  		writel_relaxed(*l2x0_regs, l2x0_base + L2X0_DATA_LATENCY_CTRL);
> > +		l2x0_regs++;
> > +		writel_relaxed(*l2x0_regs, l2x0_base + L2X0_PREFETCH_CTRL);
> > +		l2x0_regs++;
> > +		writel_relaxed(*l2x0_regs, l2x0_base + L2X0_POWER_CTRL);
> >  		/*
> >  		 * If L2 is retained do not invalidate
> >  		 */
> > -- 
> > 1.7.1
> 
> Already fixed in his tree.
> 
> [1] git://linux-arm.org/linux-2.6-lp.git sr-test-for-linaro

Thanks,
Lorenzo
>