From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751213AbaCVJz2 (ORCPT ); Sat, 22 Mar 2014 05:55:28 -0400 Received: from moutng.kundenserver.de ([212.227.126.130]:49389 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750814AbaCVJzZ (ORCPT ); Sat, 22 Mar 2014 05:55:25 -0400 From: Arnd Bergmann To: Rob Herring Subject: Re: [PATCH 0/8] Generic serial earlycon Date: Sat, 22 Mar 2014 10:54:39 +0100 User-Agent: KMail/1.12.2 (Linux/3.8.0-22-generic; KDE/4.3.2; x86_64; ; ) Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, "Greg Kroah-Hartman" , Jiri Slaby , Catalin Marinas , Russell King , Will Deacon , x86@kernel.org, Rob Herring References: <1395436128-11244-1-git-send-email-robherring2@gmail.com> In-Reply-To: <1395436128-11244-1-git-send-email-robherring2@gmail.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201403221054.39799.arnd@arndb.de> X-Provags-ID: V02:K0:7AvfroIMrMXz6szKSBtajLrmjkLu3eJBjk+Qk9dVybm kWms7cQr8wnIxDP9XoASwyN4WUYOX8Rlh+Zfoxhk1pZiGA2gu8 bvxZRSGncatF8HiLjXJcSMaC758d6cVWIDNQ92PYBguK3F8aLO Fj3qPJW1SAI8XuQVnUQkZpyibk7ZMwCtjVAUfDpr47jGo+FieL NllLEjuGqkT+QAl1/4U1CNkqiyhEj203uGWX28rvFqQ70x2ZKJ 0d3k4CSpdqR01V31HNTNCZbQsHI1Tf++K31Dom71+QQdFtFZQp 8/PDO+TMqMEeiWtvf77Vptk7iwALQ8XFELpugxFYP3mlZz2BBq azICWtCPv885I/8Tg9q+mBcY9E8CZOo3DK8uZWMDj Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 21 March 2014, Rob Herring wrote: > From: Rob Herring > > This started out as an attempt to add arm64's earlyprintk support to ARM > in order to get an earlier, runtime setup console on multi-platform > kernels. The first issue was needing the fixmap support which > conveniently Mark Salter was working on and is mostly in place now. Like > many things on ARM and arm64 now, it then became where do I put the now > common, shared code. After digging more into various early console/printk > support, it turns out the 8250_early.c setup code was the best starting > point. > > This is based on Mark Salter's fixmap support currently in linux-next. > This is tested on arm64 and ARM with pl011 and 8250. The ARM support > also requires fixmap and fixed mapping support which are not yet in place. > I have some patches in my tree to support fixmap, but they need some more > work. Fortunately, once fixmap is in place, it is just a Kconfig option > to enable earlycon support on ARM. A git tree is available here[1]. > > Based on this series, I would like to add support for doing earlycon > setup using DT. Hi Rob, I like this series a lot, great work! I would consider the DT parsing support essential here, we should not merge the patches until that is done as well, because I don't want to see users pass earlycon command line options in DT when they can use the established "linux,stdout-path" property instead. I would expect that in almost every case in which we are booting using DT today, we can just use linux,stdout-path to locate the device that the boot loader has already set up and start usign it. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 0/8] Generic serial earlycon Date: Sat, 22 Mar 2014 10:54:39 +0100 Message-ID: <201403221054.39799.arnd@arndb.de> References: <1395436128-11244-1-git-send-email-robherring2@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1395436128-11244-1-git-send-email-robherring2@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Rob Herring Cc: Rob Herring , Russell King , Catalin Marinas , x86@kernel.org, Will Deacon , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Greg Kroah-Hartman , Jiri Slaby , linux-arm-kernel@lists.infradead.org List-Id: linux-serial@vger.kernel.org On Friday 21 March 2014, Rob Herring wrote: > From: Rob Herring > > This started out as an attempt to add arm64's earlyprintk support to ARM > in order to get an earlier, runtime setup console on multi-platform > kernels. The first issue was needing the fixmap support which > conveniently Mark Salter was working on and is mostly in place now. Like > many things on ARM and arm64 now, it then became where do I put the now > common, shared code. After digging more into various early console/printk > support, it turns out the 8250_early.c setup code was the best starting > point. > > This is based on Mark Salter's fixmap support currently in linux-next. > This is tested on arm64 and ARM with pl011 and 8250. The ARM support > also requires fixmap and fixed mapping support which are not yet in place. > I have some patches in my tree to support fixmap, but they need some more > work. Fortunately, once fixmap is in place, it is just a Kconfig option > to enable earlycon support on ARM. A git tree is available here[1]. > > Based on this series, I would like to add support for doing earlycon > setup using DT. Hi Rob, I like this series a lot, great work! I would consider the DT parsing support essential here, we should not merge the patches until that is done as well, because I don't want to see users pass earlycon command line options in DT when they can use the established "linux,stdout-path" property instead. I would expect that in almost every case in which we are booting using DT today, we can just use linux,stdout-path to locate the device that the boot loader has already set up and start usign it. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Sat, 22 Mar 2014 10:54:39 +0100 Subject: [PATCH 0/8] Generic serial earlycon In-Reply-To: <1395436128-11244-1-git-send-email-robherring2@gmail.com> References: <1395436128-11244-1-git-send-email-robherring2@gmail.com> Message-ID: <201403221054.39799.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Friday 21 March 2014, Rob Herring wrote: > From: Rob Herring > > This started out as an attempt to add arm64's earlyprintk support to ARM > in order to get an earlier, runtime setup console on multi-platform > kernels. The first issue was needing the fixmap support which > conveniently Mark Salter was working on and is mostly in place now. Like > many things on ARM and arm64 now, it then became where do I put the now > common, shared code. After digging more into various early console/printk > support, it turns out the 8250_early.c setup code was the best starting > point. > > This is based on Mark Salter's fixmap support currently in linux-next. > This is tested on arm64 and ARM with pl011 and 8250. The ARM support > also requires fixmap and fixed mapping support which are not yet in place. > I have some patches in my tree to support fixmap, but they need some more > work. Fortunately, once fixmap is in place, it is just a Kconfig option > to enable earlycon support on ARM. A git tree is available here[1]. > > Based on this series, I would like to add support for doing earlycon > setup using DT. Hi Rob, I like this series a lot, great work! I would consider the DT parsing support essential here, we should not merge the patches until that is done as well, because I don't want to see users pass earlycon command line options in DT when they can use the established "linux,stdout-path" property instead. I would expect that in almost every case in which we are booting using DT today, we can just use linux,stdout-path to locate the device that the boot loader has already set up and start usign it. Arnd