From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1526395258 for ; Mon, 9 Mar 2026 10:57:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773053877; cv=none; b=VL+NGLKBD7/AuxWxTMhp3vgQQOFoApBxKYCOHUuXmeoHUz19uett5EKTjYHeMr81PDbePZ9RPMzNgNFs3SZxf6vNy3lOnWPNQZrv7AuSAGwgmEb2YgLNeS8uTFVyV8BuQAw0o0t4/3J0uwTepmaY6FVKp1Xezlo2+DQQQKt4vRc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773053877; c=relaxed/simple; bh=IlyaL0xzcKbFXRcCNMmKvq3YIxGlatU2bZ5oGniuBKo=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=S+X/WMtVtHIV3jACS/rBjYs51Dl4v4SHyAea/y/b/mRRea+HCmcqohFnB7KhLD1nubMmn5mx54cU87CjZHEwpQ0WhwcPt/CLtUK3ZaxCb/UZPAHx7ihg2mpiqtyT+WvUfPbZOtsTzASoQRvW+chzsIEUpMEwq2JIX/I/LGQIyDo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=raxXtsjy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="raxXtsjy" 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: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain 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