Subject: [PATCH] ARM: EXYNOS: Add support for secondary CPU bring-up on Exynos4412

From: [email-masked] (Tomasz Figa)
Date: Tue, 28 Aug 2012 19:43:30 +0200

Hi,

Thanks for reviewing the patch.

On Tuesday 28 of August 2012 09:21:40 Stephen Boyd wrote:
> On 8/28/2012 4:13 AM, Tomasz Figa wrote:
> > diff --git a/arch/arm/mach-exynos/platsmp.c
> > b/arch/arm/mach-exynos/platsmp.c index 36c3984..1114ced 100644
> > --- a/arch/arm/mach-exynos/platsmp.c
> > +++ b/arch/arm/mach-exynos/platsmp.c
> > @@ -34,8 +34,19 @@
> > 
> >  extern void exynos4_secondary_startup(void);
> > 
> > -#define CPU1_BOOT_REG		(samsung_rev() == EXYNOS4210_REV_1_1 ? \
> > -				S5P_INFORM5 : S5P_VA_SYSRAM)
> > +static inline volatile void *cpu_boot_reg_base(void)
> 
> __iomem?

Sorry, bad habit. I will fix it. 
 
> > +{
> > +	if (soc_is_exynos4210() && samsung_rev() == EXYNOS4210_REV_1_1)
> > +		return S5P_INFORM5;
> > +	return S5P_VA_SYSRAM;
> > +}
> > +
> > +static inline volatile void *cpu_boot_reg(int cpu)
> 
> __iomem? And why volatile?

Ditto.

> > +{
> > +	if (soc_is_exynos4412())
> > +		return cpu_boot_reg_base() + 4*cpu;
> > +	return cpu_boot_reg_base();
> > +}
> > 
> >  /*
> >  
> >   * control for which core is the next to come out of the secondary
> > 
> > @@ -195,6 +208,8 @@ void __init platform_smp_prepare_cpus(unsigned int
> > max_cpus)> 
> >  	 * until it receives a soft interrupt, and then the
> >  	 * secondary CPU branches to this address.
> >  	 */
> > 
> > -	__raw_writel(virt_to_phys(exynos4_secondary_startup),
> > -			CPU1_BOOT_REG);
> > +	for (i = 1; i < max_cpus; ++i) {
> > +		__raw_writel(virt_to_phys(exynos4_secondary_startup),
> > +							cpu_boot_reg(i));
> 
> Do you need to use cpu_logical_map()?

Correct me if I am wrong, but physical to logical CPU mapping will not be 
1:1 only if booted on physical CPU other than 0. I have not seen yet an 
Exynos-based board which does it.

However it might be wiser to use cpu_logical_map() just to be safe indeed. 
I will add it in next version of the patch.

--
Best regards,
Tomasz Figa