Re: [PATCH v3 1/5] ARM: kernel: smp_setup_processor_id() updates

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

[CC'ed Vincent following MPIDR mask query]

On Thu, Nov 15, 2012 at 01:49:51PM +0000, Will Deacon wrote:
> On Thu, Nov 15, 2012 at 12:46:50PM +0000, Lorenzo Pieralisi wrote:
> > This patch applies some basic changes to the smp_setup_processor_id()
> > ARM implementation to make the code that builds cpu_logical_map more
> > uniform across the kernel.
> > 
> > The function now prints the full extent of the boot CPU MPIDR[23:0] and
> > initializes the cpu_logical_map for CPUs up to nr_cpu_ids.
> > 
> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > ---
> >  arch/arm/kernel/setup.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> > index da1d1aa..d0df6c8 100644
> > --- a/arch/arm/kernel/setup.c
> > +++ b/arch/arm/kernel/setup.c
> > @@ -426,13 +426,14 @@ int __cpu_logical_map[NR_CPUS];
> >  void __init smp_setup_processor_id(void)
> >  {
> >  	int i;
> > -	u32 cpu = is_smp() ? read_cpuid_mpidr() & 0xff : 0;
> > +	u32 mpidr = is_smp() ? read_cpuid_mpidr() & 0xffffff : 0;
> > +	u32 cpu = mpidr & 0xff;
> 
> Can we move the #defines out of topology.c and use those instead of magic
> masks please? You could use MPIDR_HWID_BITMASK, although the LEVEL mask
> definitions over there don't look right to me (MPIDR_LEVEL0_MASK is 0x3?)

Yes, I should have done that, you are right. LEVEL0 and LEVEL1 masks look
wrong to me.

#define MPIDR_LEVEL0_MASK 0x3
#define MPIDR_LEVEL1_MASK 0xF

Vincent, why are they defined with those values ? They should all be
defined as 0xFF.

I will fix them and move them to a header file.

Thanks,
Lorenzo