Re: [PATCH v15 23/35] firmware: arm_scmi: Add Telemetry generation counter event

[Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>]

On Mon,  9 Nov 2026 09:12:09 +0000
Cristian Marussi <cristian.marussi@arm.com> wrote:

> Add a per-instance generation counter to track configuration changes which
> uses the common telemetry events framework.
Why?  What's the usecase for this?
Needs some more information or I'd leave it for now.

> 
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> ---
> v14 --> v15
>  - do NOT reset generation on RESET
> v12 --> v13
>  - update generation counter on do_xfer succcess even if failing to process
>    response since the change hass been applied: this avoids state misalignment
> v11 -->v12
>  - reviewed generation counter update logic
> v6 --> v7
>  - use new Generic event mechanism based on EventFD instead of WaitQ
> v5 --> v6
>  - add relese semantic to the atomic set of the generation counter
>  - use new eventfd_ctx common event logic
> ---
>  drivers/firmware/arm_scmi/telemetry.c | 46 ++++++++++++++++++++++++++-
>  include/linux/scmi_protocol.h         |  6 ++--
>  2 files changed, 49 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/firmware/arm_scmi/telemetry.c b/drivers/firmware/arm_scmi/telemetry.c
> index ba17204bbfc4..c21700bd1b43 100644
> --- a/drivers/firmware/arm_scmi/telemetry.c
> +++ b/drivers/firmware/arm_scmi/telemetry.c

> diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
> index af882c1e4ea4..585eb3a4684e 100644
> --- a/include/linux/scmi_protocol.h
> +++ b/include/linux/scmi_protocol.h

>  struct scmi_telemetry_de_sample {
> @@ -1003,7 +1005,7 @@ struct scmi_telemetry_de_sample {
>  };
>  
>  enum scmi_telemetry_event {
> -	SCMI_TLM_EVT_DUMMY,
> +	SCMI_TLM_EVT_GENERATION,
>  	SCMI_TLM_EVT_MAX,
>  };
>  
> @@ -1030,11 +1032,11 @@ enum scmi_telemetry_event {
>   *		    the ones belonging to a specific group when provided.
>   *		    This causes an immediate update platform-side of all the
>   *		    enabled DEs.
> - * @reset: reset configuration and telemetry data.
>   * @event_subscribe: subscribe to the specified event @type using the provided
>   *		     @eventfd_ctx.
>   * @event_unsubscribe: unsubscribe to the specified event @type the previously
>   *		       registered @eventfd_ctx.
> + * @reset: reset configuration and telemetry data.

Unrelated change.  Belongs in previous patch.

>   */
>  struct scmi_telemetry_proto_ops {
>  	const struct scmi_telemetry_info *(*info_get)