From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262816AbUCOWHc (ORCPT ); Mon, 15 Mar 2004 17:07:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262793AbUCOWHI (ORCPT ); Mon, 15 Mar 2004 17:07:08 -0500 Received: from gate.crashing.org ([63.228.1.57]:18141 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S262775AbUCOWFC (ORCPT ); Mon, 15 Mar 2004 17:05:02 -0500 Subject: Re: consistent_sync_for_cpu() and friends on ppc32 From: Benjamin Herrenschmidt To: "David S. Miller" Cc: Olaf Hering , Linux Kernel list In-Reply-To: <20040315123647.4ce943b7.davem@redhat.com> References: <20040315201616.GA31268@suse.de> <20040315123647.4ce943b7.davem@redhat.com> Content-Type: text/plain Message-Id: <1079387955.1966.177.camel@gaston> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.5 Date: Tue, 16 Mar 2004 08:59:16 +1100 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > Ben, can you work this out? I can make it compile by just making the > _for_cpu and _for_device routines behave identically to what the > consisten_sync{,_page}() stuff does now. But I'd much rather a ppc32 > person implement it correctly and optimally. > > In short, the _for_device routines should make sure cacheable data in > the cpu is fully visible to the DMA device, and _for_cpu should make > sure all device DMA is visible to the processor. Yup, it depends for what CPU the kernel is compiled, normal desktop CPUs are completely coherent, so this will be a no-op, but 4xx/8xx embedded CPUs will need something better. I'll have a look today Ben.