Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751645Ab3J2TPV (ORCPT ); Tue, 29 Oct 2013 15:15:21 -0400 Received: from mail-bk0-f45.google.com ([209.85.214.45]:59116 "EHLO mail-bk0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751040Ab3J2TPU (ORCPT ); Tue, 29 Oct 2013 15:15:20 -0400 MIME-Version: 1.0 In-Reply-To: <20131029103229.5e095a24@skate> 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> Date: Tue, 29 Oct 2013 12:15:18 -0700 Message-ID: Subject: Re: [PATCH 2/2] dma: mv_xor: Use high_base mmio where appropriate From: Dan Williams To: Thomas Petazzoni Cc: Ezequiel Garcia , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , sachin.kamat@linaro.org, Vinod Koul , dmaengine@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2247 Lines: 55 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 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. Thanks for the clarification. -- Dan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/