From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1Jimlx-0005vi-J2
	for qemu-devel@nongnu.org; Mon, 07 Apr 2008 04:32:13 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1Jimlw-0005v7-7n
	for qemu-devel@nongnu.org; Mon, 07 Apr 2008 04:32:13 -0400
Received: from [199.232.76.173] (helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1Jimlv-0005uz-NF
	for qemu-devel@nongnu.org; Mon, 07 Apr 2008 04:32:11 -0400
Received: from ug-out-1314.google.com ([66.249.92.171])
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <balrogg@gmail.com>) id 1Jimlv-000728-Ao
	for qemu-devel@nongnu.org; Mon, 07 Apr 2008 04:32:11 -0400
Received: by ug-out-1314.google.com with SMTP id m2so372552uge.4
	for <qemu-devel@nongnu.org>; Mon, 07 Apr 2008 01:32:10 -0700 (PDT)
Message-ID: <fb249edb0804070132n7405066emd0c5442697d11c20@mail.gmail.com>
Date: Mon, 7 Apr 2008 10:32:10 +0200
From: "andrzej zaborowski" <balrogg@gmail.com>
Subject: Re: [kvm-devel] [Qemu-devel] [PATCH 2/6] PCI DMA API (v2)
In-Reply-To: <200804061940.37403.paul@codesourcery.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
References: <1207368175-19476-1-git-send-email-aliguori@us.ibm.com>
	<47F8EAAB.2080806@codemonkey.ws>
	<fb249edb0804061001k2d3aac0brb4eaac23e381cdd4@mail.gmail.com>
	<200804061940.37403.paul@codesourcery.com>
Reply-To: qemu-devel@nongnu.org
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Paul Brook <paul@codesourcery.com>
Cc: Blue Swirl <blauwirbel@gmail.com>, kvm-devel@lists.sourceforge.net, qemu-devel@nongnu.org

On 07/04/2008, Paul Brook <paul@codesourcery.com> wrote:
> > As a note, the DMA controllers in the ARM system-on-chip's can
>  > byte-swap, do 90deg rotation of 2D arrays, transparency (probably
>  > intened for image blitting, but still available on any kind of
>  > transfers), etc., and most importantly issue interrupts on reaching
>  > different points of a transfer.  It is not worth worrying about them
>  > in this API.  I have been for some time wanting to make a separate api
>  > called soc_dma whose task would be using simply memcpy (or zero-copy)
>  > in the most basic case (interrupts off, no transparency,
>  > same-endianness endpoints), as these properties are common for DMA on
>  > the TI OMAPs, the Intel PXAs and the Samsung S3Cs (which otherwise
>  > have little in common).
>
> Are you sure you aren't confusing the DMA engine itelf (which is just annother
>  peripheral) with a mechanism for allowing dma engines access to the system.

I'm talking about the engine.  I want to add a generic one that will
detect the no-transformation, no-interrupts case and then possibly use
something like IOVector for a whole transfer.