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 A90D8C44524 for ; Thu, 23 Jul 2026 07:56:11 +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:Content-Type:MIME-Version: Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From: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=WrPrN9cV2PmibleLWI7XuTVzlsJZ0VJtDkclEP6rqXQ=; b=r8s4BlbQa72KDoQWUMRxGh1N4O y6mnbKrCkdl4ZS9+T7Iz7JpLkVy6cDEl5NM7JzSYNLEa/SxRDg2QGKP1ef/1/i2k9mG689cMjOHK3 E6PmB+V1ED6qdr5IgS9qN0arM9BTIEZPNqCvo0N3SMuoSkqbjZ0qg0tnwZ9OkijARz0p+fkEgNRRq JowhPeHdzjbtfagveyp2yqbElnLTisAGqAuvxeaYjqsoTy1TBBODhK+Q+DAz6vj/+adSwqN/pujJz 6aHnJJaC2AqEBKxuaXugX/qCh8/Rzzhv2OUHocaRsPtCz5a+HB1iRdiScXUxb85nCHAVAGoFytTYT FJgFPKQQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wmoHk-0000000DgNP-2LS2; Thu, 23 Jul 2026 07:56:04 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wmoHj-0000000DgNH-23CQ for linux-arm-kernel@lists.infradead.org; Thu, 23 Jul 2026 07:56:03 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id D700E41706; Thu, 23 Jul 2026 07:56:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 784001F000E9; Thu, 23 Jul 2026 07:55:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784793362; bh=WrPrN9cV2PmibleLWI7XuTVzlsJZ0VJtDkclEP6rqXQ=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=lEqG26STPwmO5CnbjQJ8E9MYTEoMF6Q0RlYzHX4Nl7lhQbyIPIujiRUHYQjir+d/r B1mUvrIxbGAUNBfgR6NfnqRt4926ESZt3Qv/4JTDflifujpN+scI9OwAjAny/fumqq j4EEZ/LU+loG0nI4gTL97ef1bUmhzwM5iK6p16Uj/Nf+/MIXuEIVh1TJSf02475CsX IiKhOaANjC7IAD35rAXrpftJ6WMj661dSOdnuvU9fMhnFw8I+jsx76AZuguSSb/jjo nrXiLZs8d9TUWYRfr5Vdy1XoEL/lxAM4RS4nzIwNdYLgMkE7uNtEuR8/Ekab8knrKy 7jSLQNu+2Z2xA== X-Mailer: emacs 30.2 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V To: linux-coco@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Catalin Marinas , Greg KH , Jeremy Linton , Jonathan Cameron , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Will Deacon , Steven Price , Suzuki K Poulose , Andre Przywara Subject: Re: [PATCH v8 0/6] Switch Arm SMCCC firmware services to an SMCCC bus In-Reply-To: <20260707081351.1680209-1-aneesh.kumar@kernel.org> References: <20260707081351.1680209-1-aneesh.kumar@kernel.org> Date: Thu, 23 Jul 2026 13:25:52 +0530 Message-ID: MIME-Version: 1.0 Content-Type: text/plain 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 "Aneesh Kumar K.V (Arm)" writes: > As discussed here: > https://lore.kernel.org/all/20250728135216.48084-12-aneesh.kumar@kernel.org > > The earlier CCA guest support used an arm-cca-dev platform device as a pure > software anchor for the TSM class device. That platform device did not > correspond to a DT/ACPI described device, MMIO range, interrupt, or other > platform resource; it existed only to make the CCA guest driver bind and to > place the resulting TSM device in the driver model. The same pattern also > exists for smccc_trng. Creating separate platform devices for such > SMCCC-discovered features is misleading, because those features are not > independent platform devices. > > This series adds an Arm SMCCC bus for services discovered through the SMCCC > firmware interface. The bus provides SMCCC device and driver registration > helpers, name-based matching, uevent modalias generation, and a sysfs modalias > attribute. SMCCC service drivers can use MODULE_DEVICE_TABLE(arm_smccc, ...) > to emit arm_smccc: aliases, allowing userspace to autoload service > drivers when the SMCCC core registers matching firmware-service devices. > > The series then moves SMCCC TRNG and the Arm CCA guest RSI service off the > platform bus. When the SMCCC core discovers the corresponding firmware > service, it registers an arm-smccc device for that service. The hwrng > arm_smccc_trng driver and the Arm CCA guest TSM provider are converted to > SMCCC drivers that bind to those discovered devices. > > The old arm-cca-dev platform device has also been used by userspace as a Realm > guest indicator. Removing it without a replacement would leave userspace > depending on an internal driver-binding device. This series therefore adds > /sys/firmware/cca/realm_guest as a stable, architecture-provided ABI for > detecting whether the kernel is running as an Arm CCA Realm guest, and then > removes the dummy arm-cca-dev platform-device registration. > Hi Will and Catalin, Gentle ping. Can this be picked up for the next merge window? -aneesh