linux-kernel - RE: [PATCH V2] ARM: EXYNOS: cpu hotplug: use v7_exit_coherency

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Message-id: <034c01cf6b2c$6f3dd510$4db97f30$@samsung.com>
Date:	Fri, 09 May 2014 11:14:40 +0900
From:	Kukjin Kim <kgene.kim@...sung.com>
To:	'Chanwoo Choi' <cw00.choi@...sung.com>,
	'Leela Krishna Amudala' <leela.krishna@...aro.org>
Cc:	linux-pm@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	daniel.lezcano@...aro.org, nicolas.pitre@...aro.org,
	amit.kucheria@...aro.org
Subject: RE: [PATCH V2] ARM: EXYNOS: cpu hotplug: use v7_exit_coherency_flush
 macro for cache disabling

Chanwoo Choi wrote:
> 
> Hi,
> 
> On 04/23/2014 02:52 PM, Leela Krishna Amudala wrote:
> > A common macro v7_exit_coherency_flush available which does the below
> tasks in
> > the seqeunce.
> > -clearing C bit
> > -clearing L1 cache
> > -exit SMP
> > -instruction and data synchronization
> >
> > So removing the local functions which does the same thing and use the
> macro instead.
> >
> > Signed-off-by: Leela Krishna Amudala <leela.krishna@...aro.org>
> > Acked-by: Nicolas Pitre <nico@...aro.org>
> > ---
> > Changes since V1:
> > 	- removed unwanted primary_part variable in exynos_cpu_die()
> > 	- given more description in commit message
> > 	  suggested by Daniel Lezcano <daniel.lezcano@...aro.org>
> >
> >  arch/arm/mach-exynos/hotplug.c |   63
+---------------------------------
> ------
> >  1 file changed, 1 insertion(+), 62 deletions(-)
> >
> > diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-
> exynos/hotplug.c
> > index 5eead53..9ca692d 100644
> > --- a/arch/arm/mach-exynos/hotplug.c
> > +++ b/arch/arm/mach-exynos/hotplug.c
> > @@ -24,56 +24,6 @@
> >  #include "common.h"
> >  #include "regs-pmu.h"
> >
> > -static inline void cpu_enter_lowpower_a9(void)
> > -{
> > -	unsigned int v;
> > -
> > -	asm volatile(
> > -	"	mcr	p15, 0, %1, c7, c5, 0\n"
> > -	"	mcr	p15, 0, %1, c7, c10, 4\n"
> > -	/*
> > -	 * Turn off coherency
> > -	 */
> > -	"	mrc	p15, 0, %0, c1, c0, 1\n"
> > -	"	bic	%0, %0, %3\n"
> > -	"	mcr	p15, 0, %0, c1, c0, 1\n"
> > -	"	mrc	p15, 0, %0, c1, c0, 0\n"
> > -	"	bic	%0, %0, %2\n"
> > -	"	mcr	p15, 0, %0, c1, c0, 0\n"
> > -	  : "=&r" (v)
> > -	  : "r" (0), "Ir" (CR_C), "Ir" (0x40)
> > -	  : "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_louis();
> > -
> > -	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;
> > @@ -132,19 +82,8 @@ 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.
> > -	 * 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.
> > -	 */
> > -	asm("mrc p15, 0, %0, c0, c0, 0" : "=r"(primary_part) : : "cc");
> > -	if ((primary_part & 0xfff0) == 0xc0f0)
> > -		cpu_enter_lowpower_a15();
> > -	else
> > -		cpu_enter_lowpower_a9();
> > +	v7_exit_coherency_flush(louis);
> >
> >  	platform_do_lowpower(cpu, &spurious);
> >
> >
> 
> I tested this patch on Exynos3250 based on Cortex-A7 dual core.
> 
> Tested-by: Chanwoo Choi <cw00.choi@...sung.com>
> 
OK, will apply, thanks.

- Kukjin

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