From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Szyprowski Subject: Re: [PATCH/RFC 0/2] serial: samsung: add support for early console Date: Tue, 23 Sep 2014 15:08:41 +0200 Message-ID: <542170D9.4020605@samsung.com> References: <1411391655-6291-1-git-send-email-m.szyprowski@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mailout4.w1.samsung.com ([210.118.77.14]:47101 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751688AbaIWNIp (ORCPT ); Tue, 23 Sep 2014 09:08:45 -0400 Received: from eucpsbgm2.samsung.com (unknown [203.254.199.245]) by mailout4.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NCC00IOLVB7C400@mailout4.w1.samsung.com> for linux-samsung-soc@vger.kernel.org; Tue, 23 Sep 2014 14:11:31 +0100 (BST) In-reply-to: Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Alim Akhtar Cc: "linux-samsung-soc@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Alim Akhtar , Thomas P Abraham , Tomasz Figa , Kyungmin Park , Rob Herring Hello, On 2014-09-23 14:53, Alim Akhtar wrote: > Hi Marek, > > On Mon, Sep 22, 2014 at 6:44 PM, Marek Szyprowski > wrote: >> Hello, >> >> This patchset adds support for early console defined in device tree. As >> an example, DTS files for all Exynos4 based machines are updated with >> the correct value for common chosen/sdtout property. >> >> To get it fully functional additional improvements (support for >> early_ioremap) are needed in early console code. >> > Is these really tested? I've tested it on Exynos4412 based OdroidU3 board. It works fine, although early console is not initialized as early as it might be. That's the only drawback, besides that it works fine. > So that mean we need to wait till __ioremap__ support available for ARM. > How to take this forward then? Here is a platform (exynos7) which > needs earlycon support for debugging some of the early core things and > ARM64 has ioremap support as well. There is no reason why we should > hold earlycon support for exyons7. I prefer to simply merge the patch as is. Once early con gets full functionality, all required samsung code will be already in then. > I see two solution here: > 1> How about re-spin patch-1 which will just add ealrycon support for > __exynos4210__ serial type only? And rest of the types can be added as > incremental patches, as and when ioremap for ARM available. > Atleast this approch will solve exynos7 problem of not having earlycon support. > And This patch can be tested on exynos7 (I can do that). > 2> Take my patch which is working and tested for exynos7 and can be > easily extended and generalized when ioremap for ARM is available. > > My preference would be the the first one. > Let me know your thoughts please. > In case you are ok with 1st approach, can you please re-spin patch1 > with needed changes? Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.szyprowski@samsung.com (Marek Szyprowski) Date: Tue, 23 Sep 2014 15:08:41 +0200 Subject: [PATCH/RFC 0/2] serial: samsung: add support for early console In-Reply-To: References: <1411391655-6291-1-git-send-email-m.szyprowski@samsung.com> Message-ID: <542170D9.4020605@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello, On 2014-09-23 14:53, Alim Akhtar wrote: > Hi Marek, > > On Mon, Sep 22, 2014 at 6:44 PM, Marek Szyprowski > wrote: >> Hello, >> >> This patchset adds support for early console defined in device tree. As >> an example, DTS files for all Exynos4 based machines are updated with >> the correct value for common chosen/sdtout property. >> >> To get it fully functional additional improvements (support for >> early_ioremap) are needed in early console code. >> > Is these really tested? I've tested it on Exynos4412 based OdroidU3 board. It works fine, although early console is not initialized as early as it might be. That's the only drawback, besides that it works fine. > So that mean we need to wait till __ioremap__ support available for ARM. > How to take this forward then? Here is a platform (exynos7) which > needs earlycon support for debugging some of the early core things and > ARM64 has ioremap support as well. There is no reason why we should > hold earlycon support for exyons7. I prefer to simply merge the patch as is. Once early con gets full functionality, all required samsung code will be already in then. > I see two solution here: > 1> How about re-spin patch-1 which will just add ealrycon support for > __exynos4210__ serial type only? And rest of the types can be added as > incremental patches, as and when ioremap for ARM available. > Atleast this approch will solve exynos7 problem of not having earlycon support. > And This patch can be tested on exynos7 (I can do that). > 2> Take my patch which is working and tested for exynos7 and can be > easily extended and generalized when ioremap for ARM is available. > > My preference would be the the first one. > Let me know your thoughts please. > In case you are ok with 1st approach, can you please re-spin patch1 > with needed changes? Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland