From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754798AbcAWUO1 (ORCPT ); Sat, 23 Jan 2016 15:14:27 -0500 Received: from www.linutronix.de ([62.245.132.108]:50422 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753934AbcAWUOU (ORCPT ); Sat, 23 Jan 2016 15:14:20 -0500 Subject: Re: [PATCH 3/4] tty: serial: 8250: omap: convert to using cyclic transfers To: Peter Hurley , John Ogness , gregkh@linuxfoundation.org, vinod.koul@intel.com References: <87zivxq57d.fsf@linutronix.de> <56A25959.4060802@hurleysoftware.com> Cc: dan.j.williams@intel.com, tony@atomide.com, nsekhar@ti.com, peter.ujfalusi@ti.com, dmaengine@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org From: Sebastian Andrzej Siewior Message-ID: <56A3DF17.2070908@linutronix.de> Date: Sat, 23 Jan 2016 21:14:15 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.5.0 MIME-Version: 1.0 In-Reply-To: <56A25959.4060802@hurleysoftware.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/22/2016 05:31 PM, Peter Hurley wrote: > Hi John, > > On 01/22/2016 02:27 AM, John Ogness wrote: >> Note that an ugly device-tree lookup hack is implemented in order >> to detect if the sDMA engine is being used. This is necessary >> because the sDMA driver does not implement pause/resume correctly >> and therefore requires slightly different logic for the UART >> driver. > > No, this is not acceptable. > > Please work with Vinod to refine the dma_get_slave_caps() interface > so that dmaengine drivers that don't provide the _documented_ pause/resume > support can be identified generically. But we could implement the pause/resume bits correctly wait until it is merge and post this and rely on the fact that it works (including error checking). RMK requested that he wants the UART driver fixed before touching the DMA driver and this has been done in meantime. So we could go ahead and add the missing pieces to SDMA. > Regards, > Peter Hurley > Sebastian