From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752045AbdGFJdd (ORCPT ); Thu, 6 Jul 2017 05:33:33 -0400 Received: from foss.arm.com ([217.140.101.70]:35726 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750778AbdGFJdb (ORCPT ); Thu, 6 Jul 2017 05:33:31 -0400 Cc: Sudeep Holla , Rob Herring , Linux Kernel Mailing List , Devicetree List , Alexey Klimov , Jassi Brar Subject: Re: [PATCH v2 2/6] Documentation: devicetree: add bindings to support ARM MHU doorbells To: Jassi Brar References: <1495621003-4291-1-git-send-email-sudeep.holla@arm.com> <1495621003-4291-3-git-send-email-sudeep.holla@arm.com> <20170531170801.u6d4fhsfu5mmqgta@rob-hp-laptop> <9a38040c-8062-870e-ab2a-beb4934428b3@arm.com> <73cf3d55-f2ec-eb15-746a-0db5e7e28dad@arm.com> <1e1fc7b3-ba5a-da30-a601-3b79122ff959@arm.com> From: Sudeep Holla Organization: ARM Message-ID: <012a9039-23e0-be8c-add9-2c0e83a1d97e@arm.com> Date: Thu, 6 Jul 2017 10:33:27 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/07/17 10:27, Jassi Brar wrote: > On Thu, Jul 6, 2017 at 2:48 PM, Sudeep Holla wrote: >> Hi Jassi, >> >> On 06/07/17 07:28, Jassi Brar wrote: >>> On Wed, Jul 5, 2017 at 11:32 PM, Sudeep Holla wrote: >>> >>>> >>>> I have posted the SCMI patches now[1], >>>> >>> I wish I was CC'ed on that. Now LKML seems too busy to forward it. >>> >> >> Yes, my mistake, I should have cc-ed you. >> >>>> please let me know how to get >>>> both SCPI and SCMI working together with different doorbell bits on the >>>> same channel. >>>> >>> You say in the cover letter : >>> "Let me begin admitting that we are introducing yet another protocol to >>> achieve same things as many existing protocols like ARM SCPI, TI SCI, >>> QCOM RPM, Nvidia Tegra BPMP, and so on" >>> >>> So SCMI is supposed to replace SCPI, SCI, RPM and BPMP or SCMI is >>> to be used for future platforms. >>> If SCPI and SCMI achieve the same, why have them both active simultaneously? >>> >> >> Yes it may not be used, but the firmware might support both for backward >> compatibility. E.g. on Juno, we still may continue supporting SCPI while >> we transition to SCMI. So both old and new DTs must work. >> > Sure, but still there is no reason to have both SCMI and SCPI active > during _runtime_. > Either SCMI or SCPI should be populated by DT, not both. > >>> Assuming there really is some sane excuse :- >> >> Yes as I mentioned above. >> > If you specify only one of SCPI/SCMI, you wouldn't need the shim arbitrator. > I said it *may not be used*, currently it is used. Also can you please answer other questions I had on mailbox API and not breaking SCPI exiting users ? I need your suggestion to proceed on that. Similar to SCPI, SCMI will be used by other platforms which must have doorbell mailbox mechanism. -- Regards, Sudeep