From nobody Thu Apr 2 12:13:36 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5C8F8383C79; Sun, 29 Mar 2026 16:35:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774802125; cv=none; b=LVUa/UZJW+usHOOcUx0dcWHDU1OPyxEgcyz33TEAeSb9MOZrnbYIh249P8+Mx3pa1mSwU+iHUNYpgz+VcKl/S4lRO4Hha01nZJOurf0FvxypnBSCQ8tW2rOoYGwmfimC3TlsruoE7Ak0YVvSyWZCSR4L+g2X6E6fRe8jnsHslVQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774802125; c=relaxed/simple; bh=X5bQX4K+cTC/K+nhDPIcHiJ5J7cork8b4fvkU8+UoWo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=uwegVcZQRYr5ozdj3KGBP9y7bQPs/sqT2Zgbh44q3PVo7OAbh59LYRImFkQP5SqDA0QgX75+lTPNgviQHCULDSQ9pX8PpMpLP+0ntUFXXGbgPfqnhYd06PwV7lzmpdwQcDwakz0dzkgpBgnlRJ+9/NpLpjxJVhZy/VdITSM9H1Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=JALzPN0k; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="JALzPN0k" 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 0959A3627; Sun, 29 Mar 2026 09:35:17 -0700 (PDT) Received: from pluto.fritz.box (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EE88A3F915; Sun, 29 Mar 2026 09:35:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1774802122; bh=X5bQX4K+cTC/K+nhDPIcHiJ5J7cork8b4fvkU8+UoWo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JALzPN0kghD2dAwz5PdtYNSzjWo15WTEJbxk0eB5CwaLWWU6g1kax/gIv1ysH84WP C+WfHG/y3sRjH28P+1UnMBYmpUWDhMiGYcHmda0d+WkLDsug16eyt1H/DCtE9/o/nq 2x0XuF+kTF33CPek5QEwSuO/acI12cjU044EoZiY= From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org Cc: sudeep.holla@kernel.org, james.quinlan@broadcom.com, f.fainelli@gmail.com, vincent.guittot@linaro.org, etienne.carriere@st.com, peng.fan@oss.nxp.com, michal.simek@amd.com, dan.carpenter@linaro.org, d-gole@ti.com, jonathan.cameron@huawei.com, elif.topuz@arm.com, lukasz.luba@arm.com, philip.radford@arm.com, brauner@kernel.org, souvik.chakravarty@arm.com, Cristian Marussi Subject: [PATCH v3 21/24] [RFC] docs: stlmfs: Document ARM SCMI Telemetry FS ABI Date: Sun, 29 Mar 2026 17:33:32 +0100 Message-ID: <20260329163337.637393-22-cristian.marussi@arm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260329163337.637393-1-cristian.marussi@arm.com> References: <20260329163337.637393-1-cristian.marussi@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Add full ABI dcoumentation for stlmfs under testing/ Signed-off-by: Cristian Marussi --- v2-->v3 - complete ABI entries docs RFC since the documentation is still NOT complete and unsure if place this into stable/ or testing/ --- Documentation/ABI/testing/stlmfs | 297 +++++++++++++++++++++++++++++++ 1 file changed, 297 insertions(+) create mode 100644 Documentation/ABI/testing/stlmfs diff --git a/Documentation/ABI/testing/stlmfs b/Documentation/ABI/testing/s= tlmfs new file mode 100644 index 000000000000..0d9b1c1885a2 --- /dev/null +++ b/Documentation/ABI/testing/stlmfs @@ -0,0 +1,297 @@ +What: /sys/fs/arm_telemetry/tlm_/all_des_enable +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A boolean WO entry to enable all the discovered Data Events f= or + SCMI instance . +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/all_tstamp_des_enable +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A boolean WO entry to enable timestamps for all the discovered + Data Events for SCMI instance . (when available) +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/available_update_intervals_ms +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry that returns a space separated list of tuples of + values, separated by a coma, each one representing a + configurable update interval for SCMI instance . + Each tuple describes a possible update interval using the + format , where the final represented interval is + calculated as: * 10 ^ + An example of list of tuples that can be read from this entry: + 3,0 4,-1 75,-2 300,-3 1,1 5,3 222,-7 +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/by_components/ +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A subdirectory that exposes an alternative topological view of + the same set of discovered DEs that can be already found under + the des/ branch. + This topology subtree is built following this structure: + by_components/ + =E2=94=9C=E2=94=80=E2=94=80 + =E2=94=82=C2=A0=C2=A0 =E2=94=9C=E2=94=80=E2=94=80 + =E2=94=82=C2=A0=C2=A0 =E2=94=82=C2=A0=C2=A0 =E2=94=9C=E2=94=80=E2=94= =80 + =E2=94=82=C2=A0=C2=A0 =E2=94=82=C2=A0=C2=A0 =E2=94=82=C2=A0=C2=A0 = =E2=94=94=E2=94=80=E2=94=80 + =E2=94=82=C2=A0=C2=A0 =E2=94=82=C2=A0=C2=A0 =E2=94=82=C2=A0=C2=A0 = =E2=94=94=E2=94=80=E2=94=80 0x[] -> ../../../../../des/0x= + + The leaves are actual symlinks to an existing des/0x + subdirectory, while the naming of the subdirectories composing + the inner nodes of the subtree are derived from the DataEvent + Descriptor in SCMI v4.0 3.12.4.6. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/control +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: An RW entry that can be used to discover, configure and retri= eve + Telemetry data using the alternative binary interface based on + ioctls which is documented in include/uapi/linux/scmi.h +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/current_update_intervals_ms +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: An RW entry that can be used to get or set the platform update + interval for SCMI instance . + On read the returned tuple represents the current update + interval using the format , where the final + represented interval is calculated as: * 10 ^ + On write the accepted format is the same as on read , + but, optionally, the second element of the tuple can be omitted + and in that case the assumed value for the exponent will default + to -3, i.e. milliseconds. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/de_implementation_version +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry that returns a string representing the 128bit UUID + that uniquely identifies the set of SCMI Telemetry Data Events + and their semantic for SCMI instance . + This is compliant with the DE_IMPLEMENTATION_REVISION described + in SCMI v4.0 Telemetry 3.12.4.3. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des_bulk_read +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry that returns a multi-line string containing all the + the DEs enabled for SCMI instance , one-per-line, formatted + as: + These DEs readings represent the last value updated by the + platform following the configured update interval: on the + backend they will have been collected transparently in a number + of different ways: on-demand SHMTI lookup, notifications, + fastchannels. + Any disabled or unavailable DE is simply NOT included. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des_single_sample_read +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry that returns a multi-line string containing all the + the DEs enabled for SCMI instance , one-per-line, formmatted + as: + These DEs readings are generated by triggering an explicit and + immediate platform update using single sample asynchronous + collect methods. + Any disabled or unavailable DE is simply NOT included. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/intervals_discrete +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A boolean RO entry to specify if the intervals reported for + SCMI instance in available_update_intervals_ms are a list of + discrete intervals or a triplet of values representing + . +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/reset +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A boolean WO entry that can be used the full reset of the SCMI + Telemetry subsystem, both of the configurations and of the + collected data, as specified in SCMI v4.0 3.12.4.12 +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/tlm_enable +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A boolean RW entry that can be used to get or set the general + enable status of the Telemetry subsystem. Temporarily disabling + Telemetry as a whole does NOT reset the current configuration, + it only stops all the configured DEs updates platform side. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/version +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry used to report the SCMI Telemetry protocol version + used in this implementation. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/compo_instance_id +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry to report the component instance to which this DE + belongs, as described by the DataEvent Descriptor in SCMI v4.0 + 3.12.4.6. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/compo_type +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry to report the component type to which this DE is + associated, as described by the DataEvent Descriptor in SCMI v4.0 + 3.12.4.6. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/instance_id +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry to report the DE instance ID that identifies this = DE + within the component instance to which it belongs, as described + by the DataEvent Descriptor in SCMI v4.0 3.12.4.6. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/name +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A optional RO entry to report the name associated with this D= E, + as described by the DataEvent Descriptor in SCMI v4.0 3.12.4.6. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/persistent +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO boolean to report that the DE data values are persistent + across all reboot cycles, except cold reboot, as described by + the DataEvent Descriptor in SCMI v4.0 3.12.4.6. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/tstamp_rate +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: An optional RO entry to report the clock rate in KHZ used to + generate the timestamps associated to this DE, as described by + the DataEvent Descriptor in SCMI v4.0 3.12.4.6. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/type +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry to report the type of DataEvent as described by the + DataEvent Descriptor in SCMI v4.0 3.12.4.6. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/unit +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry to report the unit of measurements used by this DE, + as described by the DataEvent Descriptor in SCMI v4.0 3.12.4.6. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/unit_exp +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry to report the power-of-10 multiplier in two's + complement format that is applied to the unit specified by the + DE unit field, as described by the DataEvent Descriptor in SCMI + v4.0 3.12.4.6. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/value +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry used to read the last value and timestamp collected + for Data Event with id 0x for SCMI instance . + The output is formatted as: : + Reading from this entry can fail with: + -ENODATA: the DE itself, or the whole telemetry subsystem, + was in a disabled state at the time of the read. + -EINVAL: the data value associated to this DE is NOT usable + since it was found to have been internally marked as + DATA_INVALID; this could be due to a temporary or + permanent error condition of the underlying hardware + in charge of this DE data collection. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/enable +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RW boolean entry used to enable or disable Data Event + with id 0x for SCMI instance . +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/des/0x/tstamp_enable +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: An RW boolean entry used to enable or disable timestamping for + Data Event with id 0x for SCMI instance . + This entry is optional and present only if the DE supports + timestamping. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/groups// +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A subdirectory containing entries that describe configurations + and values related to group of SCMI instance . + Most of the contained entries share the same names with some + other, already defined entries, elsewhere: + + groups/0/ + =E2=94=9C=E2=94=80=E2=94=80 available_update_intervals_ms + =E2=94=9C=E2=94=80=E2=94=80 control + =E2=94=9C=E2=94=80=E2=94=80 current_update_interval_ms + =E2=94=9C=E2=94=80=E2=94=80 des_bulk_read + =E2=94=9C=E2=94=80=E2=94=80 des_single_sample_read + =E2=94=9C=E2=94=80=E2=94=80 enable + =E2=94=9C=E2=94=80=E2=94=80 intervals_discrete + =E2=94=94=E2=94=80=E2=94=80 tstamp_enable + + These homonyms carry the same syntax and semantic as the other + but they are usually restricted in their definitions to the + specific group . + These common entries won't be described further again here. +Users: Any userspace telemetry tool + +What: /sys/fs/arm_telemetry/tlm_/groups//composing_des +Date: May 2026 +KernelVersion: 7.2 +Contact: cristian.marussi@arm.com +Description: A RO entry that reports the space separated list of DataEvents + belonging to group for SCMI instance +Users: Any userspace telemetry tool --=20 2.53.0