Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933639AbcCKGWI (ORCPT ); Fri, 11 Mar 2016 01:22:08 -0500 Received: from mga11.intel.com ([192.55.52.93]:21494 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751318AbcCKGVz (ORCPT ); Fri, 11 Mar 2016 01:21:55 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,319,1455004800"; d="scan'208";a="921541790" Date: Fri, 11 Mar 2016 11:56:07 +0530 From: Vinod Koul To: Boris Brezillon Cc: Maxime Ripard , Dan Williams , dmaengine@vger.kernel.org, Chen-Yu Tsai , linux-sunxi@googlegroups.com, Emilio =?iso-8859-1?Q?L=F3pez?= , 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: <20160311062607.GP11154@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> <20160309120627.67612b1d@bbrezillon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160309120627.67612b1d@bbrezillon> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 509 Lines: 15 On Wed, Mar 09, 2016 at 12:06:27PM +0100, Boris Brezillon wrote: > 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... Is the WAIT cycle different for different usages or same for all usages/channels? -- ~Vinod