Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752967AbdLMK7e (ORCPT ); Wed, 13 Dec 2017 05:59:34 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:60309 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752944AbdLMK7a (ORCPT ); Wed, 13 Dec 2017 05:59:30 -0500 Date: Wed, 13 Dec 2017 11:59:18 +0100 From: Maxime Ripard To: =?iso-8859-1?Q?Myl=E8ne?= Josserand Cc: wens@csie.org, linux@armlinux.org.uk, robh+dt@kernel.org, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, thomas.petazzoni@free-electrons.com Subject: Re: [PATCH 4/4] arm: dts: sun8i: a83t: Set timer node to use phy timer Message-ID: <20171213105918.tah3ihvmropmeu5g@flea.lan> References: <20171211075001.6100-1-mylene.josserand@free-electrons.com> <20171211075001.6100-5-mylene.josserand@free-electrons.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="wfsikcsn4qtmrfl3" Content-Disposition: inline In-Reply-To: <20171211075001.6100-5-mylene.josserand@free-electrons.com> User-Agent: NeoMutt/20171027 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2484 Lines: 68 --wfsikcsn4qtmrfl3 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Mon, Dec 11, 2017 at 08:50:01AM +0100, Myl=E8ne Josserand wrote: > By default, virtual timers are used. These timers need an offset > that must be set by firmware, for example. In case of SMP support, > after a reset, this offset is in "unknown" state and produced > a hang of the kernel. >=20 > Use "arm,cpu-registers-not-fw-configured" property allows to use > physical timers instead of virtual ones. >=20 > Signed-off-by: Myl=E8ne Josserand Your commit log could be a little better, something like: " The ARM architected timers use an offset between their physical and virtual counters. That offset should be configured by the bootloader in CNTVOFF. However, the A83t bootloader fails to do so, and we end up with an undefined offset (which in our case is random), meaning that each CPU will have a different time, which isn't working very well. Fix that by setting the arm,cpu-registers-not-fw-configured that will make Linux use the physical timers instead of the virtual ones. One possible side effect would be that the virtualization features would be disabled. However, due to the way the GIC has been integrated in the system, it is already unusable so we're effectively not losing any feature. " The commit title should be improved too. Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com --wfsikcsn4qtmrfl3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEE0VqZU19dR2zEVaqr0rTAlCFNr3QFAloxB/4ACgkQ0rTAlCFN r3TFHA/+Js42XtFnTP5NBvioER97S6IwB9WM/Fvv/iUfaDyG1HhXm6zh5rArGhUN v5SUUXIL8B5rOJBqOC7BMMvMiBrvmXrM2hXNk7x0EPijaIq89EvtBlzlTfqjP858 keRx1oyLMBr46Vd5bFi9IMut0IZN9lc+1amVTqZ2z69qMV5/8RLD6b78D+Y8vGB2 1n0tCLtB5D7CyGACdAd9LAciI2tGcFdWC5VJpPPgT0Ghdll/tAwSPpUzcpeK+uwO v/9GF9yL9fD6gwcCcHcTORT1LUUM/Aq4gu3gSCK8wTmUn03NJLy3ipM3Xjm2cTQA 10EKVnor8eYAJlE6WygRRzP0mSpquRtom+rSqQlu3AM71mmgrz9p5c3N4XZ5iZ9U 4/eh8lRQs4dH/8yLvOX4LRXtWfWnY5l2aRIW9wBnFfyOOrJYpCKvqGV62wdCi7nW ksvLol4lvbgfTMX6JhaaDE+LXqtoFo482RzeigTK1dSkA6rTK/dywNcMCSMTzMXC 309jIkN5OUWXmy9hk0dplVMRMeWv/ys+K2g5vtdGyt3oECkeZ/6UeNP2WKJ0Pgyi DXjfwHYbyXUQxzLNfc8p35pwJflHggTCor1hTUpPwASoSKIz4b5YGLf3nPzqoZ8b UY0SqYh1Y5K+IQo/gjrs6S3JpsvUdbOGHQVPlAYjG+/ciF/726U= =Y82Q -----END PGP SIGNATURE----- --wfsikcsn4qtmrfl3--