Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753363AbcJDNrB convert rfc822-to-8bit (ORCPT ); Tue, 4 Oct 2016 09:47:01 -0400 Received: from smtp5-g21.free.fr ([212.27.42.5]:4311 "EHLO smtp5-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751918AbcJDNq7 (ORCPT ); Tue, 4 Oct 2016 09:46:59 -0400 Date: Tue, 4 Oct 2016 15:46:51 +0200 From: Jean-Francois Moine To: Thomas Petazzoni Cc: =?ISO-8859-1?Q?Myl=E8ne?= Josserand , vinod.koul@intel.com, maxime.ripard@free-electrons.com, wens@csie.org, mturquette@baylibre.com, sboyd@codeaurora.org, lgirdwood@gmail.com, broonie@kernel.org, perex@perex.cz, tiwai@suse.com, lee.jones@linaro.org, mark.rutland@arm.com, robh+dt@kernel.org, devicetree@vger.kernel.org, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com, alexandre.belloni@free-electrons.com, dmaengine@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 01/14] dma: sun6i-dma: Add burst case of 4 Message-Id: <20161004154651.3d0eb02badb6dc66758dd3aa@free.fr> In-Reply-To: <20161004141221.55327f1b@free-electrons.com> References: <3a2404510b5f8b16ae3bb193982d70f158700b2b.1475571575.git.mylene.josserand@free-electrons.com> <20161004124011.d7f5754a082d5f17d5185fc4@free.fr> <20161004141221.55327f1b@free-electrons.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; armv7l-unknown-linux-gnueabihf) Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2051 Lines: 55 On Tue, 4 Oct 2016 14:12:21 +0200 Thomas Petazzoni wrote: > > > Add the case of a burst of 4 which is handled by the SoC. > > > > > > Signed-off-by: Myl?ne Josserand > > > --- > > > drivers/dma/sun6i-dma.c | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c > > > index 8346199..0485204 100644 > > > --- a/drivers/dma/sun6i-dma.c > > > +++ b/drivers/dma/sun6i-dma.c > > > @@ -240,6 +240,8 @@ static inline s8 convert_burst(u32 maxburst) > > > switch (maxburst) { > > > case 1: > > > return 0; > > > + case 4: > > > + return 1; > > > case 8: > > > return 2; > > > default: > > > -- > > > 2.9.3 > > > > This patch has already been rejected by Maxime in the threads > > http://www.spinics.net/lists/dmaengine/msg08610.html > > and > > http://www.spinics.net/lists/dmaengine/msg08719.html > > > > I hope you will find the way he wants for this maxburst to be added. > > I was about to reply to Mylene's e-mail, suggesting that she should add > a comment in the code (and maybe in the commit log) to explain why this > addition is needed, and also that even though the schematics say that > value "1" (max burst size of 4 bytes) is reserved, it is in fact > incorrect. The Allwinner BSP code is really using this value, and it's > the value that makes audio work, so we believe the datasheet is simply > incorrect. > > We already discussed it with Maxime, so I believe he should agree this > time. But I would suggest to have such details explained in the commit > log and in a comment in the code. Strange. Looking at the datasheets of the A23, A31, A33, A83T and H3 (these are the SoCs using the DMA sun6i), only the H3 can have 4 as the burst size (the doc is unclear for the A31). Well, I was submitting for the H3, Myl?ne is submitting for the A33. So, what about the A23, A31 and A83T? -- Ken ar c'henta? | ** Breizh ha Linux atav! ** Jef | http://moinejf.free.fr/