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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 E98E2C1B0F2 for ; Wed, 20 Jun 2018 09:53:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD97420693 for ; Wed, 20 Jun 2018 09:53:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AD97420693 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754199AbeFTJxf (ORCPT ); Wed, 20 Jun 2018 05:53:35 -0400 Received: from foss.arm.com ([217.140.101.70]:34764 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752595AbeFTJxc (ORCPT ); Wed, 20 Jun 2018 05:53:32 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 18D5980D; Wed, 20 Jun 2018 02:53:32 -0700 (PDT) Received: from [10.1.206.73] (en101.cambridge.arm.com [10.1.206.73]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 71DB73F589; Wed, 20 Jun 2018 02:53:27 -0700 (PDT) Subject: Re: [PATCH 00/20] coresight: Update device tree bindings To: linux-arm-kernel@lists.infradead.org, xuwei5@hisilicon.com, lipengcheng8@huawei.com, orsonzhai@gmail.com, zhang.lyra@gmail.com, Andy Gross , David Brown , "Ivan T . Ivanov" , Stefan Agner , shawnguo@kernel.org, =?UTF-8?Q?Beno=c3=aet_Cousson?= , Tony Lindgren , Nicolas Ferre , Linus Walleij , Liviu Dudau , Sudeep Holla , Lorenzo Pieralisi Cc: mathieu.poirier@linaro.org, robh@kernel.org, frowand.list@gmail.com, mark.rutland@arm.com, sudeep.holla@arm.com, arm@kernel.org, linux-kernel@vger.kernel.org, matt.sealey@arm.com, john.horley@arm.com, charles.garcia-tobin@arm.com, coresight@lists.linaro.org, devicetree@vger.kernel.org, mike.leach@linaro.org References: <1528235011-30691-1-git-send-email-suzuki.poulose@arm.com> From: Suzuki K Poulose Message-ID: <7b03e604-3792-7846-56dc-d3feae5410d8@arm.com> Date: Wed, 20 Jun 2018 10:53:26 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <1528235011-30691-1-git-send-email-suzuki.poulose@arm.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/06/18 22:43, Suzuki K Poulose wrote: > Coresight uses DT graph bindings to describe the connections of the > components. However we have some undocumented usage of the bindings > to describe some of the properties of the connections. > > The coresight driver needs to know the hardware ports invovled > in the connection and the direction of data flow to effectively > manage the trace sessions. So far we have relied on the "port" > address (as described by the generic graph bindings) to represent > the hardware port of the component for a connection. > ... > There were three options considered for the hardware port number scheme: > ... > 3) Use explicit properties (implemented in the series) for the hardware > port id and direction. We define a new property "coresight,hwid" for > each endpoint in coresight devices to specify the hardware port number > explicitly. Also use a separate property "direction" to specify the > direction of the data flow. > > e.g, > > port@0{ > reg = <0>; > endpoint { > direction = <1>; // Output > coresight,hwid = <0>; // Port # 0 > } > }; > > port@1{ > reg = <1>; > endpoint { > direction = <0>; // Input > coresight,hwid = <0>; // Port # 0 > }; > }; > > Pros: > - The bindings are formal and reader friendly, and less prone to errors. > Cons: > - Backward compatibility is lost. > > > This series implements Option (3) listed above and falls back to the old > bindings if the new bindings are not available. This allows the systems > with old bindings work with the new driver. The driver now issues a warning > (once) when it encounters the old bindings. .... > dts: juno: Update coresight bindings for hw port > dts: hisilicon: Update coresight bindings for hw ports > dts: spreadtrum: Update coresight bindings for hw ports > dts: qcom: Update coresight bindings for hw ports > dts: arm: hisilicon: Update coresight bindings for hardware port > dts: arm: imx7{d,s}: Update coresight binding for hardware ports > dts: arm: omap: Update coresight bindings for hardware ports > dts: arm: qcom: Update coresight bindings for hardware ports > dts: sama5d2: Update coresight bindings for hardware ports > dts: ste-dbx5x0: Update coresight bindings for hardware port > dts: tc2: Update coresight bindings for hardware ports > All, Pleas hold on with applying the DTS changes listed above. There are still some on going discussions on the bindings and we are yet to come to a conclusion [0]. And there are high chances that these might change. Sorry for the inconvenience. [0] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-June/582269.html Kind regards Suzuki