Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755754AbZCUM31 (ORCPT ); Sat, 21 Mar 2009 08:29:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753432AbZCUM3T (ORCPT ); Sat, 21 Mar 2009 08:29:19 -0400 Received: from mba.ocn.ne.jp ([122.1.235.107]:61034 "EHLO smtp.mba.ocn.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752914AbZCUM3S convert rfc822-to-8bit (ORCPT ); Sat, 21 Mar 2009 08:29:18 -0400 Date: Sat, 21 Mar 2009 21:29:20 +0900 (JST) Message-Id: <20090321.212920.25912728.anemo@mba.ocn.ne.jp> To: dan.j.williams@intel.com Cc: linux-mips@linux-mips.org, ralf@linux-mips.org, linux-kernel@vger.kernel.org, haavard.skinnemoen@atmel.com Subject: Re: [PATCH 1/2] dmaengine: TXx9 Soc DMA Controller driver From: Atsushi Nemoto In-Reply-To: References: <20090318.110154.76582864.nemoto@toshiba-tops.co.jp> X-Fingerprint: 6ACA 1623 39BD 9A94 9B1A B746 CA77 FE94 2874 D52F X-Pgp-Public-Key: http://wwwkeys.pgp.net/pks/lookup?op=get&search=0x2874D52F X-Mailer: Mew version 5.2 on Emacs 21.4 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1512 Lines: 35 On Wed, 18 Mar 2009 10:26:13 -0700, Dan Williams wrote: > > The atmel-mci does not select "channel". ?It just pick the first > > usable channel of the dma_device specified by platform_data. ?I > > suppose dw_dmac is symmetric (it can use any channel for any slave). > > You are right, it does not hardwire the channel, but it does hardwire > the device, see at32_add_device_mci [1]. > > > But TXx9 SoC DMAC channels are hardwired to each peripheral devices. > > I think creating a dma_device instance per channel and specifying that > device like atmel-mci is the more future-proof way to go. Well, I have considered it but it looks overkill for me at that time. Maybe time to think again... > > And I want to call Channel-3 of DMAC-0 "dma0chan3" even if Channel-2 > > was assigned to for public memcpy channel. > > The problem is you could pass in the chan_id to guarantee 'chan3', but > there is no guarantee that you will get 'dma0', as the driver has no > knowledge of what other dma devices may be in the system. Yes, I do not expect 'dma0'. My filter function uses dev_name(chan->device->dev), which is "txx9dmac.0" in this case. Anyway, "one dma-device per channel" manner will make things much simpler. --- Atsushi Nemoto -- 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/