From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753345Ab1H3LZL (ORCPT ); Tue, 30 Aug 2011 07:25:11 -0400 Received: from mga09.intel.com ([134.134.136.24]:40539 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751044Ab1H3LZJ (ORCPT ); Tue, 30 Aug 2011 07:25:09 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,351,1309762800"; d="scan'208";a="43325117" Subject: Re: [PATCH] serial: sh-sci: don't filter on DMA device, use only channel ID From: Vinod Koul To: Guennadi Liakhovetski Cc: Magnus Damm , Paul Mundt , linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org, Dan Williams , Magnus Damm In-Reply-To: References: <1308916071.1536.4.camel@vkoul-udesk3> <20110829080047.GJ31809@linux-sh.org> <1314618931.1606.114.camel@vkoul-udesk3> <1314698522.1606.164.camel@vkoul-udesk3> Content-Type: text/plain; charset="UTF-8" Date: Tue, 30 Aug 2011 16:53:46 +0530 Message-ID: <1314703426.1606.167.camel@vkoul-udesk3> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2011-08-30 at 13:20 +0200, Guennadi Liakhovetski wrote: > On Tue, 30 Aug 2011, Vinod Koul wrote: > > > On Tue, 2011-08-30 at 09:54 +0200, Guennadi Liakhovetski wrote: > > > On Mon, 29 Aug 2011, Vinod Koul wrote: > > > > > >> You should not assign chan->private. > > > > > >> Please move this to dma_slave_control API > > > > > > > > > > > > I haven't seen any reply to this comment and this patch seems to still be > > > > > > outstanding, is there an updated version of this patch that I've missed? > > > > I don't recall seeing any updated version fixing this > > > > > > As a matter of fact, when you say "use dma_slave_control API," you > > > actually mean the dma_slave_config, right? Then, how is one supposed to > > > use it in this case? Shall we be issuing a DMA_SLAVE_CONFIG call inside of > > > the filter and check the return code? The problem is, that not all DMA > > > controllers on sh-mobile SoCs can service the same slave devices. So, if > > > we don't check in the filter we might well get an unsuitable DMA channel. > > Here you are assigning to chan->private your specific values, which > > should be moved to the dma_slave_config. > > But here you are removing the checks, and accepting the first channel > > you got, so how do you find channel is suitable or not. > > That's done in the driver's .device_alloc_chan_resources() method. It > checkx the .private pointer, tries to find a suitable channel, if it fails > - it returns -EINVAL. See > drivers/dma/shdma.c::sh_dmae_alloc_chan_resources(): > > if (param) { > const struct sh_dmae_slave_config *cfg; > > cfg = sh_dmae_find_slave(sh_chan, param); > if (!cfg) { > ret = -EINVAL; > goto efindslave; > } Now am doubly confused. Are you saying that you are using alloc_chan_resources for doing filtering?? -- ~Vinod