From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1JifPl-0005Xj-IZ
	for qemu-devel@nongnu.org; Sun, 06 Apr 2008 20:40:49 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1JifPk-0005To-2Z
	for qemu-devel@nongnu.org; Sun, 06 Apr 2008 20:40:49 -0400
Received: from [199.232.76.173] (helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1JifPj-0005Tc-UW
	for qemu-devel@nongnu.org; Sun, 06 Apr 2008 20:40:47 -0400
Received: from mail.codesourcery.com ([65.74.133.4])
	by monty-python.gnu.org with esmtps
	(TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60)
	(envelope-from <paul@codesourcery.com>) id 1JifPj-0003kC-FT
	for qemu-devel@nongnu.org; Sun, 06 Apr 2008 20:40:47 -0400
From: Paul Brook <paul@codesourcery.com>
Subject: Re: [kvm-devel] [Qemu-devel] [PATCH 2/6] PCI DMA API (v2)
Date: Sun, 6 Apr 2008 19:40:36 -0500
References: <1207368175-19476-1-git-send-email-aliguori@us.ibm.com>
	<47F8EAAB.2080806@codemonkey.ws>
	<fb249edb0804061001k2d3aac0brb4eaac23e381cdd4@mail.gmail.com>
In-Reply-To: <fb249edb0804061001k2d3aac0brb4eaac23e381cdd4@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain;
  charset="utf-8"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Message-Id: <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: qemu-devel@nongnu.org
Cc: Blue Swirl <blauwirbel@gmail.com>, kvm-devel@lists.sourceforge.net

> 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.

Paul