Re: [PATCH v2 2/6] firmware: arm_scmi: add SCMIv3.0 Sensors descriptors extensions

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On 26.10.20 21:10, Cristian Marussi wrote:
> Add support for new SCMIv3.0 Sensors extensions related to new sensors'
> features, like multiple axis and update intervals, while keeping
> compatibility with SCMIv2.0 features.
> While at that, refactor and simplify all the internal helpers macros and
> move struct scmi_sensor_info to use only non-fixed-size typing.
> 
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> ---
> v1 --> v2
> - restrict segmented intervals descriptors to single triplet
> - add proper usage of scmi_reset_rx_to_maxsz
> ---
>  drivers/firmware/arm_scmi/sensors.c | 391 ++++++++++++++++++++++++++--
>  include/linux/scmi_protocol.h       | 219 +++++++++++++++-
>  2 files changed, 584 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/firmware/arm_scmi/sensors.c b/drivers/firmware/arm_scmi/sensors.c
> index 6aaff478d032..5a18f8c84bef 100644
> --- a/drivers/firmware/arm_scmi/sensors.c
> +++ b/drivers/firmware/arm_scmi/sensors.c
> @@ -7,16 +7,21 @@
>  
>  #define pr_fmt(fmt) "SCMI Notifications SENSOR - " fmt
>  
> +#include <linux/bitfield.h>
>  #include <linux/scmi_protocol.h>
>  
>  #include "common.h"
>  #include "notify.h"
>  
> +#define SCMI_MAX_NUM_SENSOR_AXIS	64

IMHO the related 6 bit wide fields, like SENSOR_DESCRIPTION_GET "Number
of axes", should determine the maximum value, so 64 -> 63.

[...]

> +
> +/**
> + * struct scmi_sensor_info - represents information related to one of the
> + * available sensors.
> + * @id: Sensor ID.
> + * @type: Sensor type. Chosen amongst one of @enum scmi_sensor_class.
> + * @scale: Power-of-10 multiplier applied to the sensor unit.
> + * @num_trip_points: Number of maximum configurable trip points.
> + * @async: Flag for asynchronous read support.
> + * @update: Flag for continuouos update notification support.
> + * @timestamped: Flag for timestamped read support.
> + * @tstamp_scale: Power-of-10 multiplier applied to the sensor timestamps to
> + *		  represent it in seconds.
> + * @num_axis: Number of supported axis if any. Reported as 0 for scalar sensors.
> + * @axis: Pointer to an array of @num_axis descriptors.
> + * @intervals: Descriptor of available update intervals.
> + * @sensor_config: A bitmask reporting the current sensor configuration as
> + *		   detailed in the SCMI specification: it can accessed and
> + *		   modified through the accompanying macros.
> + * @name: NULL-terminated string representing sensor name as advertised by
> + *	  SCMI platform.
> + * @extended_scalar_attrs: Flag to indicate the presence of additional extended
> + *			   attributes for this sensor.
> + * @sensor_power: Extended attribute representing the average power
> + *		  consumed by the sensor in microwatts (uW) when it is active.
> + *		  Reported here only for scalar sensors.

Above line should go to @resolution below.

Best regards,

Peter

> + *		  Set to 0 if not reported by this sensor.
> + * @resolution: Extended attribute representing the resolution of the sensor.
> + *		Set to 0 if not reported by this sensor.
> + * @exponent: Extended attribute representing the power-of-10 multiplier that is
> + *	      applied to the resolution field.
> + *	      Reported here only for scalar sensors.
> + *	      Set to 0 if not reported by this sensor.
> + * @scalar_attrs: Extended attributes representing minimum and maximum
> + *		  measurable values by this sensor.
> + *		  Reported here only for scalar sensors.
> + *		  Set to 0 if not reported by this sensor.
> + */
>  struct scmi_sensor_info {
> -	u32 id;
> -	u8 type;
> -	s8 scale;
> -	u8 num_trip_points;
> +	unsigned int id;
> +	unsigned int type;
> +	int scale;
> +	unsigned int num_trip_points;
>  	bool async;
> +	bool update;
> +	bool timestamped;
> +	int tstamp_scale;
> +	unsigned int num_axis;
> +	struct scmi_sensor_axis_info *axis;
> +	struct scmi_sensor_intervals_info intervals;
>  	char name[SCMI_MAX_STR_SIZE];
> +	bool extended_scalar_attrs;
> +	unsigned int sensor_power;
> +	unsigned int resolution;
> +	int exponent;
> +	struct scmi_range_attrs scalar_attrs;
>  };