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=-4.1 required=3.0 tests=BAYES_00,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 EE5F8C433E5 for ; Wed, 15 Jul 2020 05:56:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C8AFD206D5 for ; Wed, 15 Jul 2020 05:56:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594792565; bh=WngwdGyYHv54+sJ4atFfeahvAQwaQ/tvDayGd66RYAU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Bh4MS+XWs4yJJssb7P+gi7EZIJQ49GKGxMK/oTfHhlWIsAi5ZPHFv8ycq/MVu9d8C 9/39DEz+67DKIBYD1Basqzh8+/+D0yTxrNIdBez3IzQraQFSC+Ge7dWGTUcU/qE2i8 50NycTRjrGerMPr/UjISxSfV7TMnLxw/GgfuFB1I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728761AbgGOF4F (ORCPT ); Wed, 15 Jul 2020 01:56:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:53984 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725811AbgGOF4F (ORCPT ); Wed, 15 Jul 2020 01:56:05 -0400 Received: from localhost (unknown [122.171.202.192]) (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 F184220663; Wed, 15 Jul 2020 05:56:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594792565; bh=WngwdGyYHv54+sJ4atFfeahvAQwaQ/tvDayGd66RYAU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CWjnonOMHsVKh8pGao0XttIFQLkJfxxmoZlR5YNZnk3vP98LwQSOw2RibmmR6C/x5 l9IGnYTZMUZ3g/uXhp8NxS8zI+LzY3gionXVHP7Slu8p4ZI5WT98LGlK+7dp37x3m8 mscG1Z3Tu2NptPRVGEPlHkFpg2GkbQaa0bhP3njI= Date: Wed, 15 Jul 2020 11:26:00 +0530 From: Vinod Koul To: Sugar Zhang Cc: Heiko Stuebner , Dan Williams , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 04/14] dmaengine: pl330: Add quirk 'arm,pl330-periph-burst' Message-ID: <20200715055600.GV34333@vkoul-mobl> References: <1593439555-68130-1-git-send-email-sugar.zhang@rock-chips.com> <1593439555-68130-5-git-send-email-sugar.zhang@rock-chips.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1593439555-68130-5-git-send-email-sugar.zhang@rock-chips.com> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 29-06-20, 22:05, Sugar Zhang wrote: > This patch adds the qurik to use burst transfers only > for pl330 controller, even for request with a length of 1. > > Although, the correct way should be: if the peripheral request > length is 1, the peripheral should use SINGLE request, and then > notify the dmac using SINGLE mode by src/dst_maxburst with 1. > > For example, on the Rockchip SoCs, all the peripherals can use > SINGLE or BURST request by setting GRF registers. it is possible > that if these peripheral drivers are used only for Rockchip SoCs. > Unfortunately, it's not, such as dw uart, which is used so widely, > and we can't set src/dst_maxburst according to the SoCs' specific > to compatible with all the other SoCs. > > So, for convenience, all the peripherals are set as BURST request > by default on the Rockchip SoCs. even for request with a length of 1. > the current pl330 driver will perform SINGLE transfer if the client's > maxburst is 1, which still should be working according to chapter 2.6.6 > of datasheet which describe how DMAC performs SINGLE transfers for > a BURST request. Unfortunately, it's broken on the Rockchip SoCs, > which support only matching transfers, such as BURST transfer for > BURST request, SINGLE transfer for SINGLE request. > > Finally, we add the quirk to specify pl330 to use burst transfers only. Applied, thanks -- ~Vinod