From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tyler Baker Subject: Re: [PATCH] clk: qcom: Specify LE device endianness Date: Fri, 20 Nov 2015 12:18:06 -0800 Message-ID: References: <1447108254-19864-1-git-send-email-sboyd@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-ig0-f169.google.com ([209.85.213.169]:37857 "EHLO mail-ig0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759896AbbKTUSH (ORCPT ); Fri, 20 Nov 2015 15:18:07 -0500 Received: by igcto18 with SMTP id to18so20106151igc.0 for ; Fri, 20 Nov 2015 12:18:06 -0800 (PST) In-Reply-To: <1447108254-19864-1-git-send-email-sboyd@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Stephen Boyd Cc: Mike Turquette , "linux-kernel@vger.kernel.org" , linux-clk@vger.kernel.org, linux-arm-msm@vger.kernel.org, Simon Arlott , Mark Brown On 9 November 2015 at 14:30, Stephen Boyd wrote: > All these clock controllers are little endian devices, but so far > we've been relying on the regmap mmio bus handling this for us > without explicitly stating that fact. After commit 4a98da2164cf > (regmap-mmio: Use native endianness for read/write, 2015-10-29), > the regmap mmio bus will read/write with the __raw_*() IO > accessors, instead of using the readl/writel() APIs that do > proper byte swapping for little endian devices. > > So if we're running on a big endian processor and haven't > specified the endianness explicitly in the regmap config or in > DT, we're going to switch from doing little endian byte swapping > to big endian accesses without byte swapping, leading to some > confusing results. On my apq8074 dragonboard, this causes the > device to fail to boot as we access the clock controller with > big endian IO accesses even though the device is little endian. > > Specify the endianness explicitly so that the regmap core > properly byte swaps the accesses for us. > > Reported-by: Kevin Hilman > Cc: Simon Arlott > Cc: Mark Brown > Signed-off-by: Stephen Boyd Tested-by: Tyler Baker The kernelci.org bot also reported boot failures[1] for the apq8016-sbc in next-20151120 with CONFIG_CPU_BIG_ENDIAN=y enabled. I've bisected the failure down to the same offending remap-mmio patch listed above. I've confirmed this patch applied on top of next-20151120 fixes the boot issue for the apq8016-sbc as well. Any updates or comments on this patch? I'd like to see this fix in linux-next, as it has been broken for over a week and could be masking new issues. Cheers, Tyler [1] http://kernelci.org/boot/all/job/next/kernel/next-20151120/