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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 AEFB3C432C0 for ; Tue, 3 Dec 2019 11:46:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7F5D82068E for ; Tue, 3 Dec 2019 11:46:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725907AbfLCLqQ (ORCPT ); Tue, 3 Dec 2019 06:46:16 -0500 Received: from foss.arm.com ([217.140.110.172]:40882 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725773AbfLCLqQ (ORCPT ); Tue, 3 Dec 2019 06:46:16 -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 16FCB30E; Tue, 3 Dec 2019 03:46:15 -0800 (PST) Received: from bogus (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 69F083F68E; Tue, 3 Dec 2019 03:46:13 -0800 (PST) Date: Tue, 3 Dec 2019 11:46:07 +0000 From: Sudeep Holla To: Peng Fan Cc: "robh+dt@kernel.org" , "mark.rutland@arm.com" , "jassisinghbrar@gmail.com" , "andre.przywara@arm.com" , "f.fainelli@gmail.com" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , dl-linux-imx , Viresh Kumar , Sudeep Holla , Arnd Bergmann Subject: Re: [PATCH v11 2/2] mailbox: introduce ARM SMC based mailbox Message-ID: <20191203114607.GA4171@bogus> References: <1575281525-1549-1-git-send-email-peng.fan@nxp.com> <1575281525-1549-3-git-send-email-peng.fan@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1575281525-1549-3-git-send-email-peng.fan@nxp.com> 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 (+Viresh,Arnd) On Mon, Dec 02, 2019 at 10:14:43AM +0000, Peng Fan wrote: > From: Peng Fan > > This mailbox driver implements a mailbox which signals transmitted data > via an ARM smc (secure monitor call) instruction. The mailbox receiver > is implemented in firmware and can synchronously return data when it > returns execution to the non-secure world again. > An asynchronous receive path is not implemented. > This allows the usage of a mailbox to trigger firmware actions on SoCs > which either don't have a separate management processor or on which such > a core is not available. A user of this mailbox could be the SCP > interface. > I would like to know all the use-cases for this driver ? Is this only for SCMI or will this get used with other protocols on the top. I assume the latter and hence it is preferred to keep this as a mailbox driver. I am not against this approach but the reason I ask is to avoid duplication. Viresh has suggested abstraction of transport from SCMI driver to enable other transports[1]. Couple of transports that I am aware of is this SMC/HVC and the new(still in-concept) SPCI. So I am looking for opinions on that approach. Please feel free to comment here or as part of that patch. -- Regards, Sudeep [1] https://lore.kernel.org/lkml/5c545c2866ba075ddb44907940a1dae1d823b8a1.1575019719.git.viresh.kumar@linaro.org