From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933828AbcAZIZt (ORCPT ); Tue, 26 Jan 2016 03:25:49 -0500 Received: from s3.sipsolutions.net ([5.9.151.49]:37918 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932675AbcAZIZr (ORCPT ); Tue, 26 Jan 2016 03:25:47 -0500 Message-ID: <1453796736.2759.2.camel@sipsolutions.net> Subject: Re: [PATCH] Revert "regmap-mmio: Use native endianness for read/write" From: Johannes Berg To: Mark Brown Cc: Arnd Bergmann , Simon Arlott , linux-kernel@vger.kernel.org Date: Tue, 26 Jan 2016 09:25:36 +0100 In-Reply-To: <20160125235254.GZ6588@sirena.org.uk> References: <1453759675-28461-1-git-send-email-johannes@sipsolutions.net> <6166456.VMAx8CBNIX@wuerfel> <1453761281.2164.6.camel@sipsolutions.net> <20160125235254.GZ6588@sirena.org.uk> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.1-1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2016-01-25 at 23:52 +0000, Mark Brown wrote: >  - Make the default for MMIO regmaps be explicitly little endian with >    either an ifdef for MIPS to keep it working or an explict native >    endianness tag in the DT instead of the straight revert to LE (the >    latter seems better). This makes sense, and I agree that the latter is better. >  - Convert the MMIO regmap to use reg_read() and reg_write() with >    implementations using either readX() or ioread_*be() and > equivalents for write.  This means the core does no endianness > swapping and it's all in the bus. I don't think there's ioread64be/iowrite64be, and I'm also not entirely sure how that works since it uses __raw_* internally in lib/iomap.c? > Unfortunately that all sounds a bit too big for v4.5...  perhaps a > combination of a revert of the implementation and the addition of the > native tag to the DT for v4.5 followed by the reworking of the bus > for v4.6, I really would rather keep the DT change in v4.5 since > specifying LE is just bad and we don't want that to propagate any > more than it has to. Yes, that makes sense. > From this I also conclude that we need to improve our testing of big > endian ARM systems since nobody managed to notice this all the time > this was cooking in -next. To my knowledge before I did a couple of days ago nobody ever ran i.MX6 in big endian mode :) johannes