Re: [PATCH 04/10] uapi: Add ARM SCMI definitions

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Thu, 25 Sep 2025 21:35:48 +0100
Cristian Marussi <cristian.marussi@arm.com> wrote:

> Add a number of structures and ioctls definitions used by the ARM
> SCMI Telemetry protocol.
> 
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Hi Cristian,

Main thing in here is request to add __counted_by markings for the flexible array members.

>  SYSTEM CONTROL MANAGEMENT INTERFACE (SCMI) i.MX Extension Message Protocol drivers
> diff --git a/include/uapi/linux/scmi.h b/include/uapi/linux/scmi.h
> new file mode 100644
> index 000000000000..b1a6d34fee4a
> --- /dev/null
> +++ b/include/uapi/linux/scmi.h
> @@ -0,0 +1,286 @@

> +
> +/**
> + * scmi_tlm_config  - Whole instance or group configuration
> + *
> + * @enable: Enable/Disable Telemetry for the whole instance or the group
> + * @t_enable: Enable/Disable timestamping for all the DEs belonging to a group.
I'm fairly sure that even for reserved the kernel-doc script will complain if no
documentation.  (I haven't checked if it special cases that though!)
> + * @current_update_interval: Get/Set currently active update interval for the
> + *			     whole instance or a group.
> + *
> + * Used by:
> + *	RO - SCMI_TLM_GET_CFG
> + *	WO - SCMI_TLM_SET_CFG
> + *
> + * Supported by:
> + *	control/
> + *	groups/<N>/control
> + */
> +struct scmi_tlm_config {
> +	__u8 enable;
> +	__u8 t_enable;
> +	__u8 reserved[2];
> +	__u32 current_update_interval;
> +};

> +/**
> + * scmi_tlm_grps_list  - DE-groups List
> + *
> + * @num_grps: Number of entries returned in @grps
> + * @grps: An array containing descriptors for all defined DE Groups
> + *
> + * Used by:
> + *	RW - SCMI_TLM_GET_GRP_LIST
> + *
> + * Supported by:
> + *	control/
> + */
> +struct scmi_tlm_grps_list {
> +	__u32 num_grps;
> +	struct scmi_tlm_grp_info grps[];

As below on __counted_by

> +};
> +
> +/**
> + * scmi_tlm_grp_desc  - Group descriptor
> + *
> + * @num_des: Number of DEs part of this group
> + * @composing_des: An array containing the DE IDs that belongs to this group.
> + *
> + * Used by:
> + *	RW - SCMI_TLM_GET_GRP_DESC
> + *
> + * Supported by:
> + *	groups/<N>control/
> + */
> +struct scmi_tlm_grp_desc {
> +	__u32 num_des;
> +	__u32 composing_des[];

If we can give this a __counted_by marking please do.

> +};