[PATCH 1/5] ARM: EXYNOS: fix the hotplug for Cortex-A15

[Kyungmin Park]

Hi,

On 11/6/12, Abhilash Kesavan <a.kesavan at samsung.com> wrote:
> The sequence of cpu_enter_lowpower() for Cortex-A15
> is different from the sequence for Cortex-A9.
> This patch implements cpu_enter_lowpower() for EXYNOS5
> SoC which has Cortex-A15 cores.
>
> Signed-off-by: Changhwan Youn <chaos.youn at samsung.com>
> Cc: Russell King <rmk+kernel at arm.linux.org.uk>
> Signed-off-by: Kukjin Kim <kgene.kim at samsung.com>
> Tested-by: Abhilash Kesavan <a.kesavan at samsung.com>
> ---
>  arch/arm/mach-exynos/hotplug.c |   45
> +++++++++++++++++++++++++++++++++++++--
>  1 files changed, 42 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/mach-exynos/hotplug.c
> b/arch/arm/mach-exynos/hotplug.c
> index f4d7dd2..8c06c4f 100644
> --- a/arch/arm/mach-exynos/hotplug.c
> +++ b/arch/arm/mach-exynos/hotplug.c
> @@ -20,10 +20,11 @@
>  #include <asm/smp_plat.h>
>
>  #include <mach/regs-pmu.h>
> +#include <plat/cpu.h>
>
>  #include "common.h"
>
> -static inline void cpu_enter_lowpower(void)
> +static inline void cpu_enter_lowpower_a9(void)
>  {
>  	unsigned int v;
>
> @@ -45,6 +46,35 @@ static inline void cpu_enter_lowpower(void)
>  	  : "cc");
>  }
>
> +static inline void cpu_enter_lowpower_a15(void)
> +{
> +	unsigned int v;
> +
> +	asm volatile(
> +	"	mrc	p15, 0, %0, c1, c0, 0\n"
> +	"	bic	%0, %0, %1\n"
> +	"	mcr	p15, 0, %0, c1, c0, 0\n"
> +	  : "=&r" (v)
> +	  : "Ir" (CR_C)
> +	  : "cc");
> +
> +	flush_cache_all();
> +
> +	asm volatile(
> +	/*
> +	* Turn off coherency
> +	*/
> +	"	mrc	p15, 0, %0, c1, c0, 1\n"
> +	"	bic	%0, %0, %1\n"
> +	"	mcr	p15, 0, %0, c1, c0, 1\n"
> +	: "=&r" (v)
> +	: "Ir" (0x40)
> +	: "cc");
> +
> +	isb();
> +	dsb();
> +}
> +
>  static inline void cpu_leave_lowpower(void)
>  {
>  	unsigned int v;
> @@ -103,11 +133,20 @@ static inline void platform_do_lowpower(unsigned int
> cpu, int *spurious)
>  void __ref exynos_cpu_die(unsigned int cpu)
>  {
>  	int spurious = 0;
> +	int primary_part = 0;
>
>  	/*
> -	 * we're ready for shutdown now, so do it
> +	 * we're ready for shutdown now, so do it.
> +	 * Exynos4 is A9 based while Exynos5 is A15; check the CPU part
> +	 * number by reading the Main ID register and then perform the
> +	 * appropriate sequence for entering low power.
>  	 */
> -	cpu_enter_lowpower();
> +	asm("mrc p15, 0, %0, c0, c0, 0" : "=r"(primary_part) : : "cc");
> +	if ((primary_part & 0xfff0) == 0xc0f0)
Doesn't better to use soc_is_exynos5250? Actullay, it's better to use
soc_is_exynos5 for all exynos5 series. but not it doesn't have these
macro.

Thank you,
Kyungmin Park
> +		cpu_enter_lowpower_a15();
> +	else
> +		cpu_enter_lowpower_a9();
> +
>  	platform_do_lowpower(cpu, &spurious);
>
>  	/*
> --
> 1.6.6.1
>
>
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