From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 18142309DA0; Thu, 23 Oct 2025 13:45:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761227147; cv=none; b=rvu5DzklQ9LlqcdtNCac8YkBcoEdb+PrnkMZWcfWH8qdpuTS5O/VJ60yD/jhKPICB8Z5Hw3zJvXmqUWzW8o2AqT/jOwfjahzLUDdnNap98dlfOl7S6MPZHw0g8MVzMmfjBVV52J5ujrUGrQrjQBGCZG9/5OUlFDIwn/MhQCgBF0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761227147; c=relaxed/simple; bh=EzB8z6SVOBFC7eftKCf8lx4Eqsytl0lKiORuv0MEcps=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fFhlFF6n33cpP+AfnXObqfrzV4osE3GZJW2qf8DYM9oe8ei2RhCrTcx6ugqJ9lFg4HogiK/D/9SNC6NduzmceMifk4l8f3LnBxkgAN20uLyNCsSwhUTrVcjHtdhy0y1uFakPdbM92IkLLxV8Bz2gFV/6jhwqLVlKNE48zY/UdAY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 97E8F1516; Thu, 23 Oct 2025 06:45:35 -0700 (PDT) Received: from pluto (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5DF743F63F; Thu, 23 Oct 2025 06:45:41 -0700 (PDT) Date: Thu, 23 Oct 2025 14:45:32 +0100 From: Cristian Marussi To: Marek Vasut Cc: arm-scmi@vger.kernel.org, Conor Dooley , Cristian Marussi , Florian Fainelli , Krzysztof Kozlowski , Rob Herring , Sudeep Holla , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH 1/2] dt-bindings: firmware: arm,scmi: Document arm,poll-transport property Message-ID: References: <20251023123644.8730-1-marek.vasut+renesas@mailbox.org> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251023123644.8730-1-marek.vasut+renesas@mailbox.org> On Thu, Oct 23, 2025 at 02:35:57PM +0200, Marek Vasut wrote: > Document new property arm,poll-transport, which sets all SCMI operation into > poll mode. This is meant to work around uncooperative SCP implementations, > which do not generate completion interrupts. This applies primarily on mbox > based implementations, but does also cover SMC and VirtIO ones. Hi, ..indeed I was thinking a while ago about exposing the existing force-polling switch but in my case it was purely a testing-scenario configuration, so a no-no for the DT, things are different if you have to describe an HW that has no completion IRQ also on the a2p channel... ...having said that, though, usually polling-mode is reserved to a few selected commands in a few chosen scenarios (as you may have seen), 'carpet-polling' non-for-testing for all the commands on A2P seems a lot inefficient and heavy...is it really a viable solution ? or these systems use such a low rate of SCMI messages that polling after each and every message is negligible ? ..just to understand the context... > > With this property set, such implementations which do not generate interrupts > can be interacted with, until they are fixed to generate interrupts properly. > > Note that, because the original base protocol exchange also requires some > sort of completion mechanism, it is not possible to query SCMI itself for > this property and it must be described in DT. While this does look a bit > like policy, the SCMI provider is part of the hardware, hence DT. > > Signed-off-by: Marek Vasut Thanks, Cristian