Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753459AbcCILXv (ORCPT ); Wed, 9 Mar 2016 06:23:51 -0500 Received: from down.free-electrons.com ([37.187.137.238]:41352 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753300AbcCILXp (ORCPT ); Wed, 9 Mar 2016 06:23:45 -0500 Date: Wed, 9 Mar 2016 12:06:27 +0100 From: Boris Brezillon To: Vinod Koul Cc: Maxime Ripard , Dan Williams , dmaengine@vger.kernel.org, Chen-Yu Tsai , linux-sunxi@googlegroups.com, Emilio =?UTF-8?B?TMOzcGV6?= , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] dma: sun4i: expose block size and wait cycle configuration to DMA users Message-ID: <20160309120627.67612b1d@bbrezillon> In-Reply-To: <20160308025547.GI11154@localhost> References: <1457344771-12946-1-git-send-email-boris.brezillon@free-electrons.com> <20160307145429.GG11154@localhost> <20160307160857.577bb04d@bbrezillon> <20160307203024.GD8418@lukather> <20160308025547.GI11154@localhost> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.27; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 434 Lines: 13 On Tue, 8 Mar 2016 08:25:47 +0530 Vinod Koul wrote: > > Why does dmaengine need to wait? Can you explain that I don't have an answer for that one, but when I set WAIT_CYCLES to 1 for the NAND use case it does not work. So I guess it is somehow related to how the DRQ line is controlled on the device side... -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com