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 3EE73EFCD99 for ; Mon, 9 Mar 2026 10:58:05 +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=7z1uNloZFcK2P1RS0CY2jk67G7pL+sNFuIKN/if5Dm0=; b=ajh16uJ5/dVd2GiJoBFX0oOziE ectbT2aC/sTaFzGzBubtV+DRODW+SDUmLWEPU1yDHNQJVn2IzV6Mx5DqeYYc4MRq427qty6Uc5DzZ lg/pI8r5udKnK0UIwtKzWac5WR849FmfxhwgTqv0H5cKudm68cl4bl3UDrdUudrIWfcpswsnkvOp8 4rCseguFKGnYtsubMfdQKBIm6u+vCd6d0eLDIICAqPioiOKOCcxumn9rPww9aps6Ef7PwUfBOgkyU vw0xIVb9o+UFfkgzmFIEdshgmvXAkjh3br+FCy/ytSyXOMeYuUEtJA3mh7c5F2dEOHLeKBlmWTGDs nFiIm3sg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vzYJC-000000077j9-3mhN; Mon, 09 Mar 2026 10:57:58 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vzYJB-000000077j3-2qho for linux-arm-kernel@lists.infradead.org; Mon, 09 Mar 2026 10:57:57 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id BC1BC60133; Mon, 9 Mar 2026 10:57:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4DE20C4CEF7; Mon, 9 Mar 2026 10:57:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773053876; bh=IlyaL0xzcKbFXRcCNMmKvq3YIxGlatU2bZ5oGniuBKo=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=raxXtsjynu4dcdS3YUuTzvfa0gfWyO/zp4f8tgmpFQ1aj/1BJUK1icZEKf8Kxu392 XfjkBSGCpDCUgWKe0t5Gz08v4hEl/q6j2by35/VpUuiZur0EtgLrICYNSugMguM8lP tLgrd8H+8dA35Uk85gnxU3550ji8l2VTSiDWSVsbPzlbSrmOkJaZYxvkvvWgLInrpC 4fCueOAuXga34xva5d0FgSF/S65XJjaicqowrXp1GfEM9bjkGpsz9OBG+LUFDcNCFU u2CA9dG+VIxjNRmhtq4/GE0xec6KTEcg5JhCKptIOOcb6a0ZTSX6aafZLQ6uVt+O/k ZPLKI40i+yPwQ== X-Mailer: emacs 30.2 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas , Will Deacon , Lorenzo Pieralisi , Jeremy Linton , Greg KH , Mark Rutland , Sudeep Holla , Jonathan Cameron Subject: [PATCH v3 0/2] Switch Arm CCA to use an auxiliary device from a platform device In-Reply-To: <20260309100507.2303361-1-aneesh.kumar@kernel.org> References: <20260309100507.2303361-1-aneesh.kumar@kernel.org> Date: Mon, 09 Mar 2026 16:27:49 +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 As discussed here: https://lore.kernel.org/all/20250728135216.48084-12-aneesh.kumar@kernel.org The generic feedback was that a platform device should not be used when there is no underlying platform resource to represent. The existing CCA support uses a platform device solely to anchor the TSM interface in the device hierarchy, which is not an appropriate use of a platform device. Instead, introduce an auxiliary device to track CCA support. The TSM framework uses the device abstraction to provide cross-architecture TSM and TEE I/O functionality, including: Enumerating available platform TEE I/O capabilities Provisioning connections between the platform TSM and device DSM For the CCA platform, the resulting device hierarchy appears as follows: # cd /sys/class/tsm/ # ls -al total 0 drwxr-xr-x 2 root root 0 Jan 1 00:01 . drwxr-xr-x 23 root root 0 Jan 1 00:00 .. lrwxrwxrwx 1 root root 0 Jan 1 00:01 tsm0 -> ../../devices/platform/arm-smccc/arm_cca_host.arm-rmi-dev.0/tsm/tsm0 -aneesh