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 0F50EC9EC86 for ; Mon, 12 Jan 2026 12:54:16 +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=MbPw3lwzA3ql6z33PUTbwGJZrpQ8qK9h6XydFaTHiug=; b=oP1HwCH2yy5MlPTi4DmdyeX10S qt4IWDI2nf1Sa565sgMTuuhFg+cgVenDynp2PbrDclAhDi/8kip0d1rZaaI+xcLIJEL6Ba6Qk8dNN 4+ECvWNTHvZUwWXoRWuWC19WL5x9L7wsS6velmhDj7VPD5ubBj70Sp3Ba9fFc14/tzWzylETNJdcd gmCRim9j8GwQ81TmV+DVaGiH6RSqSMXJ6SPeqrsVbpPGWYVZ5QCQOOBwZGfYzws5RSuTj7YulhT47 zQmc3t416WriWXTrU1UnrkneJdidNE9BOqMZEffj0aGZz7piS6o/eBlHULGK6bmHbRVmjhd9rfzHA +FMzLdbA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vfHQu-00000005M1k-3nkm; Mon, 12 Jan 2026 12:54:08 +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 1vfHQt-00000005M1J-02Cy for linux-arm-kernel@lists.infradead.org; Mon, 12 Jan 2026 12:54:08 +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 92369497; Mon, 12 Jan 2026 04:53:56 -0800 (PST) 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 EDFE83F694; Mon, 12 Jan 2026 04:54:01 -0800 (PST) Date: Mon, 12 Jan 2026 12:53:54 +0000 From: Cristian Marussi To: Sudeep Holla Cc: Marek Vasut , arm-scmi@vger.kernel.org, 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 2/2] firmware: arm_scmi: Implement arm,poll-transport property Message-ID: References: <20251231213016.185575-1-marek.vasut+renesas@mailbox.org> <20251231213016.185575-2-marek.vasut+renesas@mailbox.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260112_045407_165539_72D90C06 X-CRM114-Status: GOOD ( 29.41 ) 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 Mon, Jan 12, 2026 at 12:06:11PM +0000, Sudeep Holla wrote: > On Wed, Dec 31, 2025 at 10:29:19PM +0100, Marek Vasut wrote: > > Implement 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 to 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. > > > > 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: Drop no IRQ handling from SMC transport and update commit message > > --- > > drivers/firmware/arm_scmi/common.h | 4 ++++ > > drivers/firmware/arm_scmi/driver.c | 4 ++++ > > 2 files changed, 8 insertions(+) > > > > diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h > > index 7c35c95fddbaf..7c9617d080a02 100644 > > --- a/drivers/firmware/arm_scmi/common.h > > +++ b/drivers/firmware/arm_scmi/common.h > > @@ -235,6 +235,9 @@ struct scmi_transport_ops { > > * to have an execution latency lesser-equal to the threshold > > * should be considered for atomic mode operation: such > > * decision is finally left up to the SCMI drivers. > > + * @no_completion_irq: Flag to indicate that this transport has no completion > > + * interrupt and has to be polled. This is similar to the > > + * force_polling below, except this is set via DT property. > > * @force_polling: Flag to force this whole transport to use SCMI core polling > > * mechanism instead of completion interrupts even if available. > > * @sync_cmds_completed_on_ret: Flag to indicate that the transport assures > > @@ -254,6 +257,7 @@ struct scmi_desc { > > int max_msg; > > int max_msg_size; > > unsigned int atomic_threshold; > > + bool no_completion_irq; > > const bool force_polling; > > My preference would be to reuse `force_polling` for this. We need to drop > const but that should be OK. Anyways I would like to know if Cristian thinks > otherwise for any reasons I might be missing to see. I would rather keep the 2 things separate since force_polling is more of a brutal low level debug/test facility and, even though it basically produces the same result as the new @no_completion_irq, if we remove it and unify it in a single boolean that can be overriden from the DT we end up in a situation in which we cannot anymore easily force_polling by switching the flag in the code since it could be overridden by a conflicting 'arm,poll-transport' DT setup. (and you have to patch DT for testing) So if we have one single underlying boolean (e.g. 'poll') and by any chance we end up with a DT containing: arm,poll-transport = false we cannot anymore override the condition by forcing in the code poll = true, since it would be switfly overridden by the DT prop. Also semantically force_polling express much more the situation. Anyway...I may be overthinking or missing something. Cheers, Cristian