Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754165Ab1FHG4Y (ORCPT ); Wed, 8 Jun 2011 02:56:24 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:35443 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753344Ab1FHG4W convert rfc822-to-8bit (ORCPT ); Wed, 8 Jun 2011 02:56:22 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=WUftxVkZmCeCsFHRCwrFJGJXaZbOi3wWR6u6UjVO8MFlXZcOjyfqPZnTJaIVE7nwTL MT81anqqDVK3xYBMM/7iR7Nzem2tgN7cu2BoevaYJba5PtHZTk+gUgNSZZI/G8ufCU6f DrbmE6tcwVcdPEUoChRMMuASqWhBD5huXwHEE= MIME-Version: 1.0 In-Reply-To: <20110608142121T.fujita.tomonori@lab.ntt.co.jp> References: <20110606094751.GC10508@n2100.arm.linux.org.uk> <20110606191041U.fujita.tomonori@lab.ntt.co.jp> <20110608142121T.fujita.tomonori@lab.ntt.co.jp> Date: Tue, 7 Jun 2011 23:56:21 -0700 X-Google-Sender-Auth: 3lExHaCsykNrAyYZHVaPiIE6-70 Message-ID: Subject: Re: [PATCH v2 1/3] dmaengine: add new dma API for max_segment_number From: Dan Williams To: FUJITA Tomonori Cc: shawn.guo@linaro.org, linux@arm.linux.org.uk, patches@linaro.org, vinod.koul@intel.com, gregkh@suse.de, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, cjb@laptop.org, linux-arm-kernel@lists.infradead.org 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: 1351 Lines: 27 On Tue, Jun 7, 2011 at 10:23 PM, FUJITA Tomonori wrote: > On Mon, 6 Jun 2011 11:48:56 -0700 > Dan Williams wrote: > >> dmaengine expands the class of dma providers to include standalone dma >> agents on a host bus (or elsewhere) in addition to the traditional bus >> mastering host-bus-adapters that the existing api understands. ?So in >> the case of slave dma the dma capabilities of the block-device are >> irrelevant because another agent will do the transfer on behalf of the >> block-device driver. ?So the value should be whatever the dma device >> driver says it is. > > The dma parameter restriction could be due to software (HBA drivers, > or subsystem). The value should be whatever the dma device driver says > it is in such case? I'm assuming that the dma driver is taking responsibility for setting this correctly. How would this work otherwise... HBA driver or subsystem queries the dmaengine device and then sets this parameter on its behalf? In other words dmanengine *is* the subsystem, if I am understanding your definition. -- 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/