Hi Tomasz,
On 04/26/2014 09:25 AM, Tomasz Figa wrote:
> Hi Chanwoo,
>
> On 25.04.2014 03:16, Chanwoo Choi wrote:
>> This patch decide proper lowpower mode of either a15 or a9 according to own
>> ID
>> from Main ID register.
>>
>> Cc: Arnd Bergmann <a...@arndb.de>
>> Cc: Marc Zynigier <marc.zyng...@arm.com>
>> Signed-off-by: Chanwoo Choi <cw00.c...@samsung.com>
>> Acked-by: Kyungmin Park <kyungmin.p...@samsung.com>
>> ---
>> arch/arm/mach-exynos/hotplug.c | 19 ++++++++++++-------
>> 1 file changed, 12 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/arm/mach-exynos/hotplug.c b/arch/arm/mach-exynos/hotplug.c
>> index 5eead53..acf3119 100644
>> --- a/arch/arm/mach-exynos/hotplug.c
>> +++ b/arch/arm/mach-exynos/hotplug.c
>> @@ -135,16 +135,21 @@ 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
>> - * number by reading the Main ID register and then perform the
>> - * appropriate sequence for entering low power.
>> + * Prepare the CPU for shutting down. The required sequence of
>> + * operations depends on core type. CPUID part number can be used to
>> + * determine the right way.
>> */
>> - asm("mrc p15, 0, %0, c0, c0, 0" : "=r"(primary_part) : : "cc");
>> - if ((primary_part & 0xfff0) == 0xc0f0)
>> + primary_part = read_cpuid_part_number();
>> +
>> + switch (primary_part) {
>> + case ARM_CPU_PART_CORTEX_A7:
>> + case ARM_CPU_PART_CORTEX_A15:
>> cpu_enter_lowpower_a15();
>> - else
>> + break;
>> + default:
>> cpu_enter_lowpower_a9();
>> + break;
>> + }
>>
>> platform_do_lowpower(cpu, &spurious);
>>
>>
>
> I have noticed Leela Krishna Amudala's patch [1] that removes this
> distinction completely and simply uses generic code. Could you check if this
> works on Exynos3250 as well? If yes, then this patch could be dropped and
> Leela's one would be enough.
>
> [1]
> http://www.mail-archive.com/linux-samsung-soc@vger.kernel.org/msg29064.html
OK, I tested this patch[1] to turn on secondary CPu on Exynos3250.
I'll drop following patch on next posting(v5) by using Leela Krishna Amudala's
patch [1].
- ARM: EXYNOS: Enter a15 lowpower mode for Exynos3250 based on Cortex-a7
Best Regards,
Chanwoo Choi
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