From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754669AbZHKOLX (ORCPT ); Tue, 11 Aug 2009 10:11:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754492AbZHKOLW (ORCPT ); Tue, 11 Aug 2009 10:11:22 -0400 Received: from waldorf.bytemark.co.uk ([212.110.162.22]:53578 "EHLO waldorf.bytemark.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753741AbZHKOLV (ORCPT ); Tue, 11 Aug 2009 10:11:21 -0400 Date: Tue, 11 Aug 2009 10:43:02 +0200 From: "Emilio G. Cota" To: Martyn Welch Cc: Greg K-H , linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org, Sebastien Dugue Subject: Re: [patch 1/5] Staging: VME Framework for the Linux Kernel Message-ID: <20090811084302.GB3251@braap.org> References: <20090803205657.964064732@mini.kroah.org> <20090803210111.GB28430@kroah.com> <20090808230145.GB27151@braap.org> <4A801644.2070009@gefanuc.com> <20090810141442.GA18456@braap.org> <20090810153127.GB23319@braap.org> <4A804D67.4080308@gefanuc.com> <20090810195048.GB3055@braap.org> <4A8125AC.30400@gefanuc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A8125AC.30400@gefanuc.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Martyn Welch wrote: > Emilio G. Cota wrote: >> Again, he (the driver writer) should know *nothing* about that. >> >> As for the scatter-gather case, what should happen is: >> >> User: hey, there's a buffer I want to transfer. here's >> a pointer and size > Buffer where? On VME or PCI, where are you transferring it to? The API I > have will allow scattered locations on VME to be copied to PCI and > visa-versa, scattered locations on PCI to be copied to VME and > visa-versa. Even scattered locations on VME to scattered locations on > PCI with a bit of effort. Admittedly our current tsi148 driver deals with the most common situation: DMA from main (master) CPU RAM to/from a VME slave. I'm not claiming we shouldn't support sg lists; however the implementation should resemble the existing sg interfaces. I'm currently working on something along those lines. Thanks, E.