From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752399AbcHIJNe (ORCPT ); Tue, 9 Aug 2016 05:13:34 -0400 Received: from lucky1.263xmail.com ([211.157.147.133]:50215 "EHLO lucky1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751220AbcHIJNb (ORCPT ); Tue, 9 Aug 2016 05:13:31 -0400 X-263anti-spam: KSV:0; X-MAIL-GRAY: 1 X-MAIL-DELIVERY: 0 X-KSVirus-check: 0 X-ABS-CHECKED: 4 X-ADDR-CHECKED: 0 X-RL-SENDER: shawn.lin@rock-chips.com X-FST-TO: linux-rockchip@lists.infradead.org X-SENDER-IP: 58.22.7.114 X-LOGIN-NAME: shawn.lin@rock-chips.com X-UNIQUE-TAG: <220e0b29d96ecfc015bdc2728062b0b8> X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 0 Subject: Re: [PATCH 1/3] dt/bindings: arm-pl330: add description of arm,pl330-periph-burst To: Lars-Peter Clausen , Vinod Koul References: <1470365602-32586-1-git-send-email-shawn.lin@rock-chips.com> <1470365602-32586-2-git-send-email-shawn.lin@rock-chips.com> <20160805033410.GJ9681@localhost> <0df0ab4f-0032-6487-2c30-b1ccd7d9ae62@metafoo.de> Cc: shawn.lin@rock-chips.com, Rob Herring , Huibin Hong , Xing Zheng , devicetree@vger.kernel.org, dianders@chromium.org, briannorris@chromium.org, Caesar Wang , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org From: Shawn Lin Message-ID: <1d42542f-c43c-5c4b-01b7-ba0ca085004a@rock-chips.com> Date: Tue, 9 Aug 2016 17:12:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <0df0ab4f-0032-6487-2c30-b1ccd7d9ae62@metafoo.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Lars-Peter, 在 2016/8/9 16:39, Lars-Peter Clausen 写道: > On 08/05/2016 09:25 AM, Shawn Lin wrote: >> Hi Vinod, >> >> 在 2016/8/5 11:34, Vinod Koul 写道: >>> On Fri, Aug 05, 2016 at 10:53:20AM +0800, Shawn Lin wrote: >>>> This patch adds the "arm,pl330-periph-burst" for arm-pl330 to >>>> support busrt mode. >>> >>> why should this be DT property. Only reason I can think of if some hw >>> versions support this and some won't. >> >> yes, if we want to support burst mode, both of the master(pl330) and >> client(several peripherals) should implement it, otherwise it will >> be broken when enabling. > > As you said, it is up to the consumer peripheral whether it supports BURST, > SINGLE or both. So this is a per client property, but you specify this as a > a global property on the producer side. Thanks for comment. yup, but what is the proper way to add it ? :) a) If pl330 support BURST as well as all the peripherals, we could enable it. b) If pl300 support BURST, but all the peripherals don't support it, we could not enable it. c) If pl300 support BURST, but not all the peripherals support it, we also could not enable it. the burst feature of peripheral IP may be vendor-specific, but the common driver for this peripheral are used for many many vendors which means we could not check all of this info. It's very likely to break them... I couldn't figure out how many upstreamed peripheral drivers who are using pl300 either. So this check should be done by all this vendors but we could make sure we don't break them before they check a), b), c), right? > > > > -- Best Regards Shawn Lin