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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EFF2CC9EC99 for ; Mon, 12 Jan 2026 16:02:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=+KmqMCQ5FHHOXu1tG1grk+l96qjTrtnJqGljFID7xJk=; b=1li6vakzsHgeSs4Dr+7EOZJP49 87o2LlYDXWdUgdpP9+D7rKzdgxcJGEneJS2blcwXVn3C1LWMb+ntyVa6MSLDERGwoIWFo2DiURiN2 EHRg/1m9WpHiMKNT5VK0bRd3BN0U9H/XYh9n6pnrqC1eYn+o+9MFhWuZcOUDFHp9CkI/FJ9C/6g1F /0bVf7GeQwZvFbq43Db6W/bUZQmw+BobnxDRYXYjl9Eh3JbN/127ZCofD6chX7Dl/XTQ1n9tK1IrP 8Tnl1L9+ExmqjbEjSU114iG+O7HJzHK0Z/kOUcc5wfLV0KJdwCkUKTqkdNQY4inhLK+8SAxyw/2dQ 8t11y4lw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vfKNI-00000005grQ-2Wl7; Mon, 12 Jan 2026 16:02:36 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vfKNG-00000005gqv-1ocz for linux-arm-kernel@lists.infradead.org; Mon, 12 Jan 2026 16:02:35 +0000 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 C9745497; Mon, 12 Jan 2026 08:02:26 -0800 (PST) Received: from bogus (e133711.arm.com [10.1.197.51]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1B4AC3F59E; Mon, 12 Jan 2026 08:02:32 -0800 (PST) Date: Mon, 12 Jan 2026 16:02:29 +0000 From: Sudeep Holla To: Krzysztof Kozlowski Cc: Marek Vasut , arm-scmi@vger.kernel.org, Sudeep Holla , Conor Dooley , Cristian Marussi , Florian Fainelli , Krzysztof Kozlowski , Rob Herring , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH v2 1/2] dt-bindings: firmware: arm,scmi: Document arm,poll-transport property Message-ID: References: <20251231213016.185575-1-marek.vasut+renesas@mailbox.org> <20260102-masked-spirited-labrador-33eae0@quoll> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260102-masked-spirited-labrador-33eae0@quoll> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260112_080234_599180_041AA46C X-CRM114-Status: GOOD ( 25.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Jan 02, 2026 at 12:39:12PM +0100, Krzysztof Kozlowski wrote: > On Wed, Dec 31, 2025 at 10:29:18PM +0100, Marek Vasut wrote: > > Document new property arm,poll-transport, which sets all SCMI operation into > > Please wrap commit message according to Linux coding style / submission > process (neither too early nor over the limit): > https://elixir.bootlin.com/linux/v6.4-rc1/source/Documentation/process/submitting-patches.rst#L597 > > > poll mode. This is meant to work around uncooperative SCP implementations, > > which do not generate completion interrupts. This applies primarily on mbox > > shmem based implementations. > > > > 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 > > --- > > Cc: Conor Dooley > > Cc: Cristian Marussi > > Cc: Florian Fainelli > > Cc: Krzysztof Kozlowski > > Cc: Rob Herring > > Cc: Sudeep Holla > > Cc: arm-scmi@vger.kernel.org > > Cc: devicetree@vger.kernel.org > > Cc: linux-arm-kernel@lists.infradead.org > > Cc: linux-renesas-soc@vger.kernel.org > > --- > > V2: s@mean@&t and limit poll transport to mailbox/shmem only > > --- > > .../devicetree/bindings/firmware/arm,scmi.yaml | 10 ++++++++++ > > 1 file changed, 10 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml > > index be817fd9cc34b..f4bf4173c5c7e 100644 > > --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml > > +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml > > @@ -146,6 +146,13 @@ properties: > > this platform. If set, the value should be non-zero. > > minimum: 1 > > > > + arm,poll-transport: > > + type: boolean > > + description: > > + An optional property which unconditionally forces polling in all transports. > > + This is mainly meant to work around uncooperative SCP, which does not generate > > Also not wrapped. > > Anyway, you described the desired Linux feature or behavior, not the > actual hardware. The bindings are about the latter, so instead you need > to rephrase the property and its description to match actual hardware > capabilities/features/configuration etc. > I agree with this assessment. Rephrasing the property to reflect the actual hardware/firmware characteristics makes more sense. Something along the lines of `arm,no-completion-interrupt`, or a similar name, would better capture the underlying reality, namely that the platform or firmware does not generate a completion interrupt without encoding OS-specific policy or behavior. -- Regards, Sudeep