From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: Re: [PATCHv2] ARM: EXYNOS: reset Little cores when cpu is up Date: Mon, 14 Sep 2015 10:24:35 +0900 Message-ID: <55F621D3.3030207@samsung.com> References: <1441117023-25478-1-git-send-email-parkch98@gmail.com> <55E63F8F.4020300@samsung.com> <55E64386.3000903@osg.samsung.com> <55E64559.7000105@samsung.com> <55E6A8F6.5020301@osg.samsung.com> <55E6AC57.4020208@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout1.w1.samsung.com ([210.118.77.11]:25317 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753201AbbINBYs (ORCPT ); Sun, 13 Sep 2015 21:24:48 -0400 Received: from eucpsbgm2.samsung.com (unknown [203.254.199.245]) by mailout1.w1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0NUN00M5Q7X9YZ90@mailout1.w1.samsung.com> for linux-samsung-soc@vger.kernel.org; Mon, 14 Sep 2015 02:24:45 +0100 (BST) In-reply-to: <55E6AC57.4020208@samsung.com> Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Javier Martinez Canillas , Chanho Park , kgene@kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, Kevin Hilman On 02.09.2015 16:59, Krzysztof Kozlowski wrote: > On 02.09.2015 16:44, Javier Martinez Canillas wrote: >> Hello Krzysztof, >> >> On 09/02/2015 02:39 AM, Krzysztof Kozlowski wrote: >>> On 02.09.2015 09:32, Javier Martinez Canillas wrote: >>>> 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 >>>>>> Cc: Javier Martinez Canillas >>>>>> Cc: Krzysztof Kozlowski >>>>>> Tested-by: Kevin Hilman >>>>>> Signed-off-by: Chanho Park >>>>>> --- >>>>>> 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 >>>>> Tested-by: Krzysztof Kozlowski >>>>> >>>>> 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. >>> >>> It is a bug fix but: >>> 1. Not a fix for regression introduced in current merge window, >> >> I thought the -rc cycle was for stabilization and fix not only regressions >> introduced during the merge window but also long standing issues. > > It's all subtle. Sometimes it also depends on the mood of maintainer... > A lot of fixes for different issues are merged in -rc and in the same > time they are rejected because they are too late and they don't fix > regression from merge window. Anyway I used the argument #1 in > combination with #2. > > Best regards, > Krzysztof > >> >>> 2. There may be more subtle issues like the one mentioned below, not >>> found yet (probably no one tested it with all possible configurations), >>> >> >> Right, this is indeed a better reason to wait for v4.4. >> >>> so I don't think rushing with the patch to mainline is good idea. >>> >> >> Yes, agreed. >> >>> However your comment reminds me about stable. This actually looks like a >>> candidate for stable. I applied the patch to my repo marking it as stable backport for v4.1+. Earlier kernels would require manual backporting/rebasing. It should be in linux-next soon. Let's see how it turns out. If no one complains than I actually agree with Javier's opinion of sending this to v4.3. Best regards, Krzysztof From mboxrd@z Thu Jan 1 00:00:00 1970 From: k.kozlowski@samsung.com (Krzysztof Kozlowski) Date: Mon, 14 Sep 2015 10:24:35 +0900 Subject: [PATCHv2] ARM: EXYNOS: reset Little cores when cpu is up In-Reply-To: <55E6AC57.4020208@samsung.com> References: <1441117023-25478-1-git-send-email-parkch98@gmail.com> <55E63F8F.4020300@samsung.com> <55E64386.3000903@osg.samsung.com> <55E64559.7000105@samsung.com> <55E6A8F6.5020301@osg.samsung.com> <55E6AC57.4020208@samsung.com> Message-ID: <55F621D3.3030207@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 02.09.2015 16:59, Krzysztof Kozlowski wrote: > On 02.09.2015 16:44, Javier Martinez Canillas wrote: >> Hello Krzysztof, >> >> On 09/02/2015 02:39 AM, Krzysztof Kozlowski wrote: >>> On 02.09.2015 09:32, Javier Martinez Canillas wrote: >>>> 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 >>>>>> Cc: Javier Martinez Canillas >>>>>> Cc: Krzysztof Kozlowski >>>>>> Tested-by: Kevin Hilman >>>>>> Signed-off-by: Chanho Park >>>>>> --- >>>>>> 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 >>>>> Tested-by: Krzysztof Kozlowski >>>>> >>>>> 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. >>> >>> It is a bug fix but: >>> 1. Not a fix for regression introduced in current merge window, >> >> I thought the -rc cycle was for stabilization and fix not only regressions >> introduced during the merge window but also long standing issues. > > It's all subtle. Sometimes it also depends on the mood of maintainer... > A lot of fixes for different issues are merged in -rc and in the same > time they are rejected because they are too late and they don't fix > regression from merge window. Anyway I used the argument #1 in > combination with #2. > > Best regards, > Krzysztof > >> >>> 2. There may be more subtle issues like the one mentioned below, not >>> found yet (probably no one tested it with all possible configurations), >>> >> >> Right, this is indeed a better reason to wait for v4.4. >> >>> so I don't think rushing with the patch to mainline is good idea. >>> >> >> Yes, agreed. >> >>> However your comment reminds me about stable. This actually looks like a >>> candidate for stable. I applied the patch to my repo marking it as stable backport for v4.1+. Earlier kernels would require manual backporting/rebasing. It should be in linux-next soon. Let's see how it turns out. If no one complains than I actually agree with Javier's opinion of sending this to v4.3. Best regards, Krzysztof