From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
Subject: Re: [PATCH v7 01/10] ARM: davinci: move private EDMA API to arm/common
Date: Tue, 5 Feb 2013 22:26:30 +0000
Message-ID: <201302052226.30754.arnd@arndb.de>
References: <1359742975-10421-1-git-send-email-mporter@ti.com>
	<20130204154153.GA18237@arwen.pp.htv.fi>
	<20130205182848.GJ25185@atomide.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
In-Reply-To: <20130205182848.GJ25185-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
List-Unsubscribe: <https://lists.sourceforge.net/lists/listinfo/spi-devel-general>,
	<mailto:spi-devel-general-request-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org?subject=unsubscribe>
List-Archive: <http://sourceforge.net/mailarchive/forum.php?forum_name=spi-devel-general>
List-Post: <mailto:spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
List-Help: <mailto:spi-devel-general-request-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org?subject=help>
List-Subscribe: <https://lists.sourceforge.net/lists/listinfo/spi-devel-general>,
	<mailto:spi-devel-general-request-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org?subject=subscribe>
Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
To: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
Cc: Matt Porter <mporter-l0cyMroinI0@public.gmane.org>, Linux DaVinci Kernel List <davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org>, Linux OMAP List <linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Russell King - ARM Linux <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>, "Cousson,
	Benoit" <b-cousson-l0cyMroinI0@public.gmane.org>, Sergei Shtylyov <sshtylyov-Igf4POYTYCDQT0dZR+AlfA@public.gmane.org>, Linux Documentation List <linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Vinod Koul <vinod.koul-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, Devicetree Discuss <devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org>, Mark Brown <broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>, Linux MMC List <linux-mmc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Linux Kernel Mailing List <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>, Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>, Rob Landley <rob-VoJi6FS/r0vR7s880joybQ@public.gmane.org>, Dan Williams <djbw-b10kYP2dOMg@public.gmane.org>, Linux SPI Devel List <spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>, Chris Ball <cjb-2X9k7bc8m7Mdnm+yROfE0A@public.gmane.org>, Linux ARM Kernel List <linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
List-Id: linux-mmc@vger.kernel.org

On Tuesday 05 February 2013, Tony Lindgren wrote:
> * Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org> [130204 07:46]:
> > 
> > Current DMA abstraction is quite poor, for example there's no way to
> > compile support for multiple DMA engines. Code also makes certain, IMO
> > unnecessary, assumptions about the underlying DMA engine (abstraction is
> > poor, as said above but it we could follow MUSB's programming guide when
> > it comes to programming DMA transfers).
> > 
> > Considering all of the above, it's far better to use DMA engine and get
> > rid of all the mess.
> 
> How about just disable MUSB DMA support if ARCH_MULTIPLATFORM for now?
> That way MUSB can be fixed up first to support ARCH_MULTIPLATFORM
> using PIO while sorting out the DMA related issues.

Sounds ok to me. Someone still needs to do the work to make the non-DMA
variants of MUSB coexist in one kernel, but as we discussed erlier, that
should be much simpler.

	Arnd

------------------------------------------------------------------------------
Free Next-Gen Firewall Hardware Offer
Buy your Sophos next-gen firewall before the end March 2013 
and get the hardware for free! Learn more.
http://p.sf.net/sfu/sophos-d2d-feb