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 6CF17C9EC98 for ; Mon, 12 Jan 2026 15:58:25 +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=Z36QOE9rQ/JyP1zjnS3tdGN/wm5VsDtu7emJlg9dcSA=; b=43ox0B+djdXy9N12FcpqaWaQHz h42PNhERtVnAogJPXMZOO7RX0LkMB2LWHZvUsOg6wAk40XjZEiLk1I6J4UhsMvZPDm00uZocH+UEq DEolYwNG3fT5CJe4auQ/BEF3YquWvpwxibm0aSz6+icos9nienUZcbHSVHGP9Ob4Nz3EWG8a7YTSd NEXj2Wh8klTmLr/Owv33WEb0ovgW5nrKG5UeOkhtaUPb8SNmWK0XUzBiqSqapI5SX4I3fJr3GKIGQ Td5e9mfWOiKIXXZHGhqMPXPdw7EOm0D9uEtzbuBqyjpv51JdYZPD6WtVl37dVAZUDnBrLkHDbBM5b ajZ+il4Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vfKJ7-00000005g9D-39me; Mon, 12 Jan 2026 15:58:17 +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 1vfKJ5-00000005g8X-0CGP for linux-arm-kernel@lists.infradead.org; Mon, 12 Jan 2026 15:58:16 +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 51B16497; Mon, 12 Jan 2026 07:58:06 -0800 (PST) Received: from bogus (e133711.arm.com [10.1.197.51]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B15533F59E; Mon, 12 Jan 2026 07:58:11 -0800 (PST) Date: Mon, 12 Jan 2026 15:58:09 +0000 From: Sudeep Holla To: Cristian Marussi Cc: Marek Vasut , arm-scmi@vger.kernel.org, Sudeep Holla , Conor Dooley , 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_075815_208035_561D27D2 X-CRM114-Status: GOOD ( 36.82 ) 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 12:53:54PM +0000, Cristian Marussi wrote: > 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. > Understood, looking at raw I did get a sense of this but didn't spend much time and thought of asking you. So, all good. Let's not mix them together then. Thanks for the details! -- Regards, Sudeep