From: javier@osg.samsung.com (Javier Martinez Canillas)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCHv2] ARM: EXYNOS: reset Little cores when cpu is up
Date: Wed, 2 Sep 2015 02:32:06 +0200 [thread overview]
Message-ID: <55E64386.3000903@osg.samsung.com> (raw)
In-Reply-To: <55E63F8F.4020300@samsung.com>
Hello Krzysztof,
On 09/02/2015 02:15 AM, Krzysztof Kozlowski wrote:
> On 01.09.2015 23:17, Chanho Park wrote:
>> The cpu booting of exynos5422 has been still broken since we discussed
>> it in last year[1]. This patch is inspired from Odroid XU3
>> code (Actually, it was from samsung exynos vendor kernel)[2]. This weird
>> reset code was founded exynos5420 octa cores series SoCs and only
>> required for the first boot core is the Little core (Cortex A7).
>> Some of the exynos5420 boards and all of the exynos5422 boards will require
>> this code.
>>
>> There is two ways to check the little core is the first cpu. One is
>> checking GPG2CON[1] GPIO value and the other is checking the cluster
>> number of the first cpu. I selected the latter because it's more easier
>> than the former.
>>
>> [1]:http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/350632.html
>> [2]:https://patchwork.kernel.org/patch/6782891/
>>
>> Cc: Kevin Hilman <khilman@kernel.org>
>> Cc: Javier Martinez Canillas <javier@osg.samsung.com>
>> Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
>> Tested-by: Kevin Hilman <khilman@linaro.org>
>> Signed-off-by: Chanho Park <parkch98@gmail.com>
>> ---
>> Changes from v1:
>> .kfc to Little (Cortex A7) and eagle to big (Cortex A15)
>> .append comments about waiting SPARE2 register
>>
>> Changes since RFC:
>> .drop checking soc_is_exynos5800 to extend this codes to
>> exynos5420/5422 boards.
>> .kfc cores will be reset only if the cpu0 is kfc core.
>> .Rebase top of the kukjin's for-next branch
>>
>> arch/arm/mach-exynos/mcpm-exynos.c | 25 ++++++++++++++++++++++++-
>> arch/arm/mach-exynos/regs-pmu.h | 6 ++++++
>> 2 files changed, 30 insertions(+), 1 deletion(-)
>
> Thanks for updating the patch. Remaining minor nit about comment style
> (/* on first line) can be fixed while applying.
>
> The patch works good, after disabling bL switcher I have 8 cores running:
>
> Tested on Odroid XU4:
> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
>
> It's 4.3 merge window so the patch will go probably to v4.4.
>
Isn't this material for the v4.3 -rc cycle since it's fixing a bug
(CPUs not booting)? So I don't think that's necessary to wait for v4.4.
But I was expecting another re-spin as from Abhilash's latest comments [0],
it seems the same workaround is needed in arch/arm/mach-exynos/platsmp.c
to avoid the CPU's not booting issue when CCI is disabled in DT and the
MCPM backend is bypassed.
Although I guess that could be also made as a follow up patch.
> Best regards,
> Krzysztof
>
>
[0]: http://www.spinics.net/lists/arm-kernel/msg442399.html
Best regards,
--
Javier Martinez Canillas
Open Source Group
Samsung Research America
next prev parent reply other threads:[~2015-09-02 0:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-01 14:17 [PATCHv2] ARM: EXYNOS: reset Little cores when cpu is up Chanho Park
2015-09-01 14:47 ` Anand Moon
2015-09-02 0:15 ` Krzysztof Kozlowski
2015-09-02 0:32 ` Javier Martinez Canillas [this message]
2015-09-02 0:39 ` Krzysztof Kozlowski
2015-09-02 7:44 ` Javier Martinez Canillas
2015-09-02 7:59 ` Krzysztof Kozlowski
2015-09-14 1:24 ` Krzysztof Kozlowski
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