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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 9F12CC352A2 for ; Fri, 7 Feb 2020 11:06:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78C1620720 for ; Fri, 7 Feb 2020 11:06:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726798AbgBGLGG (ORCPT ); Fri, 7 Feb 2020 06:06:06 -0500 Received: from foss.arm.com ([217.140.110.172]:38970 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726674AbgBGLGG (ORCPT ); Fri, 7 Feb 2020 06:06:06 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B091930E; Fri, 7 Feb 2020 03:06:05 -0800 (PST) Received: from bogus (e103737-lin.cambridge.arm.com [10.1.197.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2BFED3F68E; Fri, 7 Feb 2020 03:06:04 -0800 (PST) Date: Fri, 7 Feb 2020 11:06:02 +0000 From: Sudeep Holla To: Peng Fan Cc: Marc Zyngier , "robh+dt@kernel.org" , "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "f.fainelli@gmail.com" , "viresh.kumar@linaro.org" , "linux-kernel@vger.kernel.org" , dl-linux-imx , "andre.przywara@arm.com" , "linux-arm-kernel@lists.infradead.org" , Sudeep Holla Subject: Re: [PATCH 1/2] dt-bindings: arm: arm,scmi: add smc/hvc transports Message-ID: <20200207110602.GE36345@bogus> References: <1580994086-17850-1-git-send-email-peng.fan@nxp.com> <1580994086-17850-2-git-send-email-peng.fan@nxp.com> <7875e2533c4ba23b8ca0a2a296699497@kernel.org> <20200207104736.GB36345@bogus> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Fri, Feb 07, 2020 at 10:55:44AM +0000, Peng Fan wrote: > > Subject: Re: [PATCH 1/2] dt-bindings: arm: arm,scmi: add smc/hvc transports > > > > On Fri, Feb 07, 2020 at 10:08:36AM +0000, Marc Zyngier wrote: > > > On 2020-02-06 13:01, peng.fan@nxp.com wrote: > > > > From: Peng Fan > > > > > > > > SCMI could use SMC/HVC as tranports, so add into devicetree binding > > > > doc. > > > > > > > > Signed-off-by: Peng Fan > > > > --- > > > > Documentation/devicetree/bindings/arm/arm,scmi.txt | 4 +++- > > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/Documentation/devicetree/bindings/arm/arm,scmi.txt > > > > b/Documentation/devicetree/bindings/arm/arm,scmi.txt > > > > index f493d69e6194..03cff8b55a93 100644 > > > > --- a/Documentation/devicetree/bindings/arm/arm,scmi.txt > > > > +++ b/Documentation/devicetree/bindings/arm/arm,scmi.txt > > > > @@ -14,7 +14,7 @@ Required properties: > > > > > > > > The scmi node with the following properties shall be under the > > > > /firmware/ node. > > > > > > > > -- compatible : shall be "arm,scmi" > > > > +- compatible : shall be "arm,scmi" or "arm,scmi-smc" > > > > - mboxes: List of phandle and mailbox channel specifiers. It should > > > > contain > > > > exactly one or two mailboxes, one for transmitting messages("tx") > > > > and another optional for receiving the notifications("rx") if @@ > > > > -25,6 +25,8 @@ The scmi node with the following properties shall be > > > > under the /firmware/ node. > > > > protocol identifier for a given sub-node. > > > > - #size-cells : should be '0' as 'reg' property doesn't have any size > > > > associated with it. > > > > +- arm,smc-id : SMC id required when using smc transports > > > > +- arm,hvc-id : HVC id required when using hvc transports > > > > > > > > Optional properties: > > > > > > Not directly related to DT: Why do we need to distinguish between SMC > > > and HVC? > > > > IIUC you want just one property to get the function ID ? Does that align with > > what you are saying ? I wanted to ask the same question and I see no need for > > 2 different properties. > > The multiple protocols might use SMC or HVC. Saying > > Protocol@x { > method="smc"; > arm,func-id=<0x....> > }; > Protocol@y { > method="hvc"; > arm,func-id=<0x....> > }; > Wow, stop there. Please don't do that. You either use SMC or HVC consistently. Not both at the same time. Any particular reasons for trying such crazy things. > With my propose: > > Protocol@x { > arm,smc-id=<0x....> > }; > Protocol@y { > arm,hvc-id=<0x....> > }; > > No need an extra method property to indicate it is smc or hvc. > The driver use take arm,smc-id as SMC, arm,hvc-id as HVC. > NACK, just have one function ID, I am not very particular on the name 'smc-id' is just fine for me. But only one function ID for any conduit used and that is chosen by PSCI/SMCCC. If you need multiple channels(unique per protocol) then I suggest go for an channel ID or you can even manage just with shmem associated with it (I prefer latter but again I am fine either way) -- Regards, Sudeep