From: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Lorenzo Pieralisi <lpieralisi@kernel.org>,
Jeremy Linton <jeremy.linton@arm.com>,
Greg KH <gregkh@linuxfoundation.org>,
Mark Rutland <mark.rutland@arm.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Jonathan Cameron <jonathan.cameron@huawei.com>
Subject: [PATCH v3 0/2] Switch Arm CCA to use an auxiliary device from a platform device
Date: Mon, 09 Mar 2026 16:27:49 +0530 [thread overview]
Message-ID: <yq5av7f51d8y.fsf@kernel.org> (raw)
In-Reply-To: <20260309100507.2303361-1-aneesh.kumar@kernel.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
prev parent reply other threads:[~2026-03-09 10:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-09 10:05 [PATCH v3 1/2] firmware: smccc: coco: Manage arm-smccc platform device and CCA auxiliary drivers Aneesh Kumar K.V (Arm)
2026-03-09 10:05 ` [PATCH v3 2/2] coco: guest: arm64: Drop dummy RSI platform device stub Aneesh Kumar K.V (Arm)
2026-03-09 10:14 ` [PATCH v3 1/2] firmware: smccc: coco: Manage arm-smccc platform device and CCA auxiliary drivers Greg KH
2026-03-09 10:57 ` Aneesh Kumar K.V [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=yq5av7f51d8y.fsf@kernel.org \
--to=aneesh.kumar@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=gregkh@linuxfoundation.org \
--cc=jeremy.linton@arm.com \
--cc=jonathan.cameron@huawei.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lpieralisi@kernel.org \
--cc=mark.rutland@arm.com \
--cc=sudeep.holla@arm.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.