From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B59DC33C9E for ; Tue, 28 Jan 2020 11:50:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04CF924687 for ; Tue, 28 Jan 2020 11:50:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580212212; bh=jW6H9OlD/jgob7HlVx2GQo9Y2WJ5ofqdPX2DH4cN0ws=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=ieW9rAMu3xmd6cTSnerAbgvC7c5LKf2hd6A8M6cy9KRbYrffh33YA3md/ZEaM/LNz KRDNbGBf7cTo/ZvDkK3+dMcNIgNMLAFCjOv4sSn80U/zAty1qKNkZ5FpKcHq8UpDqm 4f2Owill7SnbDJ4cGQ+uW2CV28qhtXhnzkFagTzg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725959AbgA1LuL (ORCPT ); Tue, 28 Jan 2020 06:50:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:41048 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725905AbgA1LuL (ORCPT ); Tue, 28 Jan 2020 06:50:11 -0500 Received: from localhost (unknown [223.226.101.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 14C9F214AF; Tue, 28 Jan 2020 11:50:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580212210; bh=jW6H9OlD/jgob7HlVx2GQo9Y2WJ5ofqdPX2DH4cN0ws=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=D2cb1YugqwH2Kyc7TSXkHPyGqa4SajqkS1G/5EzKpQt0ER0jWrgg8B8kx41irg/+P BmEt88S8IfoSTGx/NcGkJg+nkUDwnlrAk26uaXIsT0nysYKSUK6RZBdYlykEVlKYRt KA1+RCXSefrCA4DP2Z8kNYqDDPctG8DwSf0SHbPk= Date: Tue, 28 Jan 2020 17:20:06 +0530 From: Vinod Koul To: Peter Ujfalusi Cc: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, dan.j.williams@intel.com, grygorii.strashko@ti.com, vigneshr@ti.com Subject: Re: [PATCH for-next 0/4] dmaengine: ti: k3-udma: Updates for next Message-ID: <20200128115006.GT2841@vkoul-mobl> References: <20200127132111.20464-1-peter.ujfalusi@ti.com> <41c53cc4-fa3e-1ab1-32b8-1d516cda7341@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <41c53cc4-fa3e-1ab1-32b8-1d516cda7341@ti.com> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 28-01-20, 12:15, Peter Ujfalusi wrote: > Vinod, > > On 27/01/2020 15.21, Peter Ujfalusi wrote: > > Hi Vinod, > > > > Based on customer reports we have identified two issues with the UDMA driver: > > > > TX completion (1st patch): > > The scheduled work based workaround for checking for completion worked well for > > UART, but it had significant impact on SPI performance. > > The underlying issue is coming from the fact that we have split data movement > > architecture. > > In order to know that the transfer is really done we need to check the remote > > end's (PDMA) byte counter. > > > > RX channel teardown with stale data in PDMA (2nd patch): > > If we try to stop the RX DMA channel (teardown) then PDMA is trying to flush the > > data is might received from a peripheral, but if UDMA does not have a packet to > > use for this draining than it is going to push back on the PDMA and the flush > > will never completes. > > The workaround is to use a dummy descriptor for flush purposes when the channel > > is terminated and we did not have active transfer (no descriptor for UDMA). > > This allows UDMA to drain the data and the teardown can complete. > > > > The last two patch is to use common code to set up the TR parameters for > > slave_sg, cyclic and memcpy. The setup code is the same as we used for memcpy > > with the change we can handle 4.2GB sg elements and periods in case of cyclic. > > It is also nice that we have single function to do the configuration. > > I have marked these patches as for-next as 5.5 was not released yet. > Would it be possible to have these as fixes for 5.6? Sure but are they really fixes, why cant they go for next release :) They seem to improve things for sure, but do we want to call them as fixes..? -- ~Vinod