Messages in this thread | | | From | Marc Zyngier <> | Subject | Re: [PATCH 06/27] ARM: EXYNOS:: Enter a15 lowpower mode for Exynos3250 based on Cortex-a7 | Date | Thu, 10 Apr 2014 13:07:32 +0100 |
| |
On Thu, Apr 10 2014 at 11:56:33 am BST, Chanwoo Choi <cw00.choi@samsung.com> wrote: > On 04/10/2014 06:51 PM, Marc Zyngier wrote: >> On Thu, Apr 10 2014 at 10:28:23 am BST, Chanwoo Choi <cw00.choi@samsung.com> wrote: >>> This patch decide proper lowpower mode of either a15 or a9 according to own ID >>> from Main ID register. >>> >>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> >>> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> >>> --- >>> arch/arm/mach-exynos/hotplug.c | 13 ++++++++++--- >>> 1 file changed, 10 insertions(+), 3 deletions(-) >>> >>> diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exynos/hotplug.c >>> index 5eead53..36d3db6 100644 >>> --- a/arch/arm/mach-exynos/hotplug.c >>> +++ b/arch/arm/mach-exynos/hotplug.c >>> @@ -135,13 +135,20 @@ void __ref exynos_cpu_die(unsigned int cpu) >>> 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 >>> + * we're ready for shutdown now, so do it. Exynos4 is A9 based >>> + * while Exynos5 is A15/Exynos7 is A7; 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"); >> >> While you're touching that code, how about using: >> >> primary_part = read_cpuid(CPUID_ID); > > Or, > I suggest read_cpuid_part_number() instead of assembler directly. > > primary_part = read_cpuid_part_number();
Yup, even better.
>> >>> - if ((primary_part & 0xfff0) == 0xc0f0) >>> + >>> + /* >>> + * Main ID register of Cortex series >>> + * - Cortex-a7 : 0x410F_C07x >>> + * - Cortex-a15 : 0x410F_C0Fx >>> + */ >>> + primary_part = primary_part & 0xfff0; >>> + if (primary_part == 0xc0f0 || primary_part == 0xc070) >> >> ARM_CPU_PART_CORTEX_A15, ARM_CPU_PART_CORTEX_A7 > > OK I'll use this defined constant as following: > > switch (primary_part) > case ARM_CPU_PART_CORTEX_A7: > case ARM_CPU_PART_CORTEX_A15: > cpu_enter_lowpower_a15(); > break; > default: > cpu_enter_lowpower_a9(); > break; > }
Looks good.
M. -- Jazz is not dead. It just smells funny.
| |