Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932515AbVIZWqA (ORCPT ); Mon, 26 Sep 2005 18:46:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932519AbVIZWqA (ORCPT ); Mon, 26 Sep 2005 18:46:00 -0400 Received: from palrel10.hp.com ([156.153.255.245]:40841 "EHLO palrel10.hp.com") by vger.kernel.org with ESMTP id S932515AbVIZWp7 (ORCPT ); Mon, 26 Sep 2005 18:45:59 -0400 Date: Mon, 26 Sep 2005 15:46:03 -0700 From: Grant Grundler To: "Luck, Tony" Cc: "John W. Linville" , Matthew Wilcox , linux-kernel@vger.kernel.org, discuss@x86-64.org, linux-ia64@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, ak@suse.de, "Mallick, Asit K" , gregkh@suse.de Subject: Re: [patch 2.6.14-rc2 0/5] swiotlb maintenance and x86_64 dma_sync_single_range_for_{cpu,device} Message-ID: <20050926224603.GD16113@esmail.cup.hp.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1328 Lines: 30 On Mon, Sep 26, 2005 at 03:08:23PM -0700, Luck, Tony wrote: > Historically swiotlb.c was written with just PCI in mind (hence > all the comments ("... implement the PCI DMA API", "The PCI address > to use is returned", "teardown the PCI dma mapping") and a few > error messages ("PCI-DMA: Out of SW-IOMMU space ...", "PCI-DMA: Memory > would be corrupted", "PCI-DMA: Random memory would be DMAed"). > Perhaps back then the only options were PCI and ISA???? Yes. The DMA interface davem/et al introduce in linux-2.4 only supported "PCI-Like" busses. Ie the API required struct pci_dev. > Matthew is probably technically right in that this is a more > generic interface ... but is it actually being used for anything > other than PCI? Will it ever be so used? Besides 32-bit PCI devices, I expect legacy 24-bit E/ISA DMA will need it. Is ISA ~= PCI? I never got a clear answer on that. I'm inclined to say it's not. But since swiotlb complies with DMA-API interface and is not related to any particular type of bus, I'd rather it go into lib/ instead of drivers/pci. hth, grant - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/