From owner-freebsd-arch@FreeBSD.ORG  Tue Jul  1 02:30:31 2003
Return-Path: <owner-freebsd-arch@FreeBSD.ORG>
Delivered-To: freebsd-arch@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id AA0CE37B401
	for <freebsd-arch@freebsd.org>; Tue,  1 Jul 2003 02:30:31 -0700 (PDT)
Received: from srv1.cosmo-project.de (srv1.cosmo-project.de [213.83.6.106])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 5212A44011
	for <freebsd-arch@freebsd.org>; Tue,  1 Jul 2003 02:30:30 -0700 (PDT)
	(envelope-from ticso@cicely12.cicely.de)
Received: from cicely5.cicely.de (cicely5.cicely.de
	[IPv6:3ffe:400:8d0:301:200:92ff:fe9b:20e7])
	by srv1.cosmo-project.de (8.12.9/8.12.9) with ESMTP id h619U5hR023305
	(version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=OK);
	Tue, 1 Jul 2003 11:30:13 +0200 (CEST)
	(envelope-from ticso@cicely12.cicely.de)
Received: from cicely12.cicely.de (cicely12.cicely.de
	[IPv6:3ffe:400:8d0:301::12])
	by cicely5.cicely.de (8.12.9/8.12.9) with ESMTP id h619U2w6036386
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO);
	Tue, 1 Jul 2003 11:30:03 +0200 (CEST)
	(envelope-from ticso@cicely12.cicely.de)
Received: from cicely12.cicely.de (localhost [127.0.0.1])
	by cicely12.cicely.de (8.12.9/8.12.9) with ESMTP id h619U2gt098000;
	Tue, 1 Jul 2003 11:30:02 +0200 (CEST)
	(envelope-from ticso@cicely12.cicely.de)
Received: (from ticso@localhost)
	by cicely12.cicely.de (8.12.9/8.12.9/Submit) id h619TkbF097996;
	Tue, 1 Jul 2003 11:29:46 +0200 (CEST)
Date: Tue, 1 Jul 2003 11:29:45 +0200
From: Bernd Walter <ticso@cicely12.cicely.de>
To: Andrew Gallatin <gallatin@cs.duke.edu>
Message-ID: <20030701092944.GE90081@cicely12.cicely.de>
References: <3EF3C12F.9060303@btc.adaptec.com>
	<16124.39930.142492.356163@grasshopper.cs.duke.edu>
	<3EFC9F2D.6020908@btc.adaptec.com>
	<16124.43999.333761.397624@grasshopper.cs.duke.edu>
	<3EFCAC7A.6060305@btc.adaptec.com>
	<16124.45051.919899.414795@grasshopper.cs.duke.edu>
	<3EFD4755.49BAF150@mindspring.com>
	<16128.17218.973911.980939@grasshopper.cs.duke.edu>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <16128.17218.973911.980939@grasshopper.cs.duke.edu>
X-Operating-System: FreeBSD cicely12.cicely.de 5.1-CURRENT alpha
User-Agent: Mutt/1.5.4i
cc: Scott Long <scott_long@btc.adaptec.com>
cc: freebsd-arch@freebsd.org
Subject: Re: API change for bus_dma
X-BeenThere: freebsd-arch@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
Reply-To: ticso@cicely.de
List-Id: Discussion related to FreeBSD architecture
	<freebsd-arch.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arch>
List-Post: <mailto:freebsd-arch@freebsd.org>
List-Help: <mailto:freebsd-arch-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 01 Jul 2003 09:30:32 -0000

On Mon, Jun 30, 2003 at 10:03:46AM -0400, Andrew Gallatin wrote:
> The idea is that I want to establish a mapping that can be used many
> times without any driver or kernel attention.  I don't want to do
> anything in terms of a system call, or interrupt, etc, to sync the
> cache with the state of the DMA'ed page before a DMA read or after a DMA
> write.
> 
> For example, scatter gather mapping on alphas (if FreeBSD supported it
> for PCI devices) would be fine with me since its cache-coherent and
> doesn't require any ddi_dma_sync() operations.

What makes you shure about alpha dma to be cache-coherent?
I'm not shure that the current implementation of _bus_dmamap_sync()
without barriers is correct.

-- 
B.Walter                   BWCT                http://www.bwct.de
ticso@bwct.de                                  info@bwct.de