From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751382AbaLQK61 (ORCPT ); Wed, 17 Dec 2014 05:58:27 -0500 Received: from mout.kundenserver.de ([212.227.126.187]:57406 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750790AbaLQK6Y (ORCPT ); Wed, 17 Dec 2014 05:58:24 -0500 From: Arnd Bergmann To: Stefan Agner Cc: linux-arm-kernel@lists.infradead.org, shawn.guo@linaro.org, kernel@pengutronix.de, linux@arm.linux.org.uk, u.kleine-koenig@pengutronix.de, jason@lakedaemon.net, olof@lixom.net, daniel.lezcano@linaro.org, tglx@linutronix.de, mark.rutland@arm.com, pawel.moll@arm.com, robh+dt@kernel.org, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 11/12] ARM: dts: add support for Vybrid running on Cortex-M4 Date: Wed, 17 Dec 2014 11:57:06 +0100 Message-ID: <2673866.7fjSqeaHyh@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: References: <1417565531-4507-1-git-send-email-stefan@agner.ch> <2994970.DCfUQgtmcD@wuerfel> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:F+hHyreeK94YnEnvN0Nn0gfiqXxQo43Ve8NpFHt5GWr3/fbp0bY Vox9/oKtFOi7k+/5ln1UH2mbGMQPlnyfzh6OW/TkqUNfMXReIX4FyMtEzQoCyy4ZraB+UPO Rm+FSiVRpQOZxoeVLvO6KzZ26QgFb6cq1BAwsKEJU3vdxiBlO+PqTHsjED/z7+bEfND9fWu KRWAZc2V1GFZviEqzJx+w== X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 16 December 2014 23:19:08 Stefan Agner wrote: > On 2014-12-03 12:03, Arnd Bergmann wrote: > > On Wednesday 03 December 2014 01:12:10 Stefan Agner wrote: > Just started looking in that a bit deeper and some question arose: > Afaik, earlycon need to be supported by the uart driver. The fsl_lpuart, > which is used for Vybrid's uart, does not support earlycon yet. However, > earlyprink already works (see ./arch/arm/include/debug/vf.S). I > understand that earlycon has the advantage of being able to be used on > multiplatform. But earlyprintk is working really early (e.g. before > locating the FDT), and it proved helpful for me when I started working > on that Cortex-M4 stuff. Should earlycon replace earlyprintk completely? earlyprintk will stay around for debugging early boot problems, but with working earlycon support, there should no longer be a reason to enable it by default. > Maybe, on Vybrid, since it would be a good platform for automated !MMU > testing, it would be nice to have earlycon which can be enabled in any > case and would provide output even something blows up quite early... But > I guess I would add earlycon support as part of a new patchset and just > drop earlyprintk here for now. Yes, I think that would be good. > > 64 hash table entries sounds extremely small, doesn't that impact > > performance? If you have 50MB of actual RAM available, I don't think > > you need that. > > Agreed. I copied that from EFM32 which is under much more memory > pressure... Ok. Arnd