From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752629Ab3J3AdU (ORCPT ); Tue, 29 Oct 2013 20:33:20 -0400 Received: from top.free-electrons.com ([176.31.233.9]:41849 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751381Ab3J3AdS (ORCPT ); Tue, 29 Oct 2013 20:33:18 -0400 Date: Tue, 29 Oct 2013 21:33:18 -0300 From: Ezequiel Garcia To: Dan Williams Cc: Thomas Petazzoni , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , sachin.kamat@linaro.org, Vinod Koul , dmaengine@vger.kernel.org Subject: Re: [PATCH 2/2] dma: mv_xor: Use high_base mmio where appropriate Message-ID: <20131030003317.GD2527@localhost> References: <1383000855-8377-1-git-send-email-ezequiel.garcia@free-electrons.com> <1383000855-8377-2-git-send-email-ezequiel.garcia@free-electrons.com> <20131029083407.GA2416@localhost> <20131029103229.5e095a24@skate> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 29, 2013 at 12:15:18PM -0700, Dan Williams wrote: > On Tue, Oct 29, 2013 at 2:32 AM, Thomas Petazzoni > wrote: > > Dan, Ezequiel, > > > > On Tue, 29 Oct 2013 05:34:08 -0300, Ezequiel Garcia wrote: > > > >> > On Mon, Oct 28, 2013 at 3:54 PM, Ezequiel Garcia > >> > wrote: > >> > > Despite requesting two memory resources, called 'base' and 'high_base', the > >> > > driver uses explicitly only the former. The latter is being used implicitly > >> > > by addressing at offset +0x200, which in practice accesses high_base. > >> > > > >> > > Instead of relying in such trick, let's define the registers with the > >> > > offset from high_base, and use high_base explicitly where appropriate. > >> > > > >> > > Signed-off-by: Ezequiel Garcia > >> > > --- > >> > > drivers/dma/mv_xor.c | 3 ++- > >> > > drivers/dma/mv_xor.h | 25 +++++++++++++------------ > >> > > 2 files changed, 15 insertions(+), 13 deletions(-) > >> > > >> > Since it's unused I'd prefer a patch that just deletes xor_high_base. > >> > > >> > >> It's wrongly *unused*, the mmio high_base is actually being used > >> implicitly by always addressing at an offset that addresses +200. > >> > >> Deleting high_base would actually make it worse, for that region > >> will no longer be ioremaped. Maybe the commit message is not clear > >> about it? > > > > I agree with Ezequiel, and I believe his patch is appropriate. The > > registers for the XOR engines are indeed split in two areas, so it > > makes sense to have this xor_base / xor_high_base split that reflects > > the register mapping passed from the Device Tree, and use this split in > > the macros used to access the registers. > > > > Ah ok, so it's a bug if an implementation ever puts the second > resource window at a non 0x200 offset. > > Ezequiel , can you resend the patch to the new Sure. > dmaengine@vger.kernel.org list (patchwork queue) and clarify that this > is a fix rather than a pure cleanup in the changelog? At least > cleanup is how I first read it. > By the way, I didn't initially Cced dmaengine list because it's not in the MAINTAINERS file. How about we add it and avoid this happening to other developers? diff --git a/MAINTAINERS b/MAINTAINERS index ebaf8bd..cd57b4a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1397,6 +1397,15 @@ F: drivers/dma/ F: include/linux/dmaengine.h F: include/linux/async_tx.h +DMAENGINE SUBSYSTEM +M: Dan Williams +L: dmaengine@vger.kernel.org +S: Maintained +F: Documentation/dmaengine.txt +F: drivers/dma/ +F: include/linux/dma/ +F: include/linux/dmaengine.h + AT24 EEPROM DRIVER M: Wolfram Sang L: linux-i2c@vger.kernel.org I'll submit the patch if you want. Just check the above is correct. If there's a git repo, it might be good to add is as well. -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com