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diff --git a/Documentation/userspace-api/media/v4l/metafmt-arm-mali-c55.rst b/Documentation/userspace-api/media/v4l/metafmt-arm-mali-c55.rst new file mode 100644 index 000000000000..696e0a645a7e --- /dev/null +++ b/Documentation/userspace-api/media/v4l/metafmt-arm-mali-c55.rst @@ -0,0 +1,84 @@ +.. SPDX-License-Identifier: GPL-2.0 + +.. _v4l2-meta-fmt-mali-c55-params: +.. _v4l2-meta-fmt-mali-c55-stats: + +***************************************************************************** +V4L2_META_FMT_MALI_C55_STATS ('C55S'), V4L2_META_FMT_MALI_C55_PARAMS ('C55P') +***************************************************************************** + +3A Statistics +============= + +The ISP device collects different statistics over an input bayer frame. Those +statistics can be obtained by userspace from the +:ref:`mali-c55 3a stats <mali-c55-3a-stats>` metadata capture video node, using +the :c:type:`v4l2_meta_format` interface. The buffer contains a single instance +of the C structure :c:type:`mali_c55_stats_buffer` defined in +``mali-c55-config.h``, so the structure can be obtained from the buffer by: + +.. code-block:: C + + struct mali_c55_stats_buffer *stats = + (struct mali_c55_stats_buffer *)buf; + +For details of the statistics see :c:type:`mali_c55_stats_buffer`. + +Configuration Parameters +======================== + +The configuration parameters are passed to the :ref:`mali-c55 3a params +<mali-c55-3a-params>` metadata output video node, using the +:c:type:`v4l2_meta_format` interface. Rather than a single struct containing +sub-structs for each configurable area of the ISP, parameters for the Mali-C55 +use the v4l2-isp parameters system, through which groups of parameters are +defined as distinct structs or "blocks" which may be added to the data member of +:c:type:`v4l2_isp_params_buffer`. Userspace is responsible for populating the +data member with the blocks that need to be configured by the driver. Each +block-specific struct embeds :c:type:`v4l2_isp_params_block_header` as its first +member and userspace must populate the type member with a value from +:c:type:`mali_c55_param_block_type`. + +.. code-block:: c + + struct v4l2_isp_params_buffer *params = + (struct v4l2_isp_params_buffer *)buffer; + + params->version = MALI_C55_PARAM_BUFFER_V1; + params->data_size = 0; + + void *data = (void *)params->data; + + struct mali_c55_params_awb_gains *gains = + (struct mali_c55_params_awb_gains *)data; + + gains->header.type = MALI_C55_PARAM_BLOCK_AWB_GAINS; + gains->header.flags |= V4L2_ISP_PARAMS_FL_BLOCK_ENABLE; + gains->header.size = sizeof(struct mali_c55_params_awb_gains); + + gains->gain00 = 256; + gains->gain00 = 256; + gains->gain00 = 256; + gains->gain00 = 256; + + data += sizeof(struct mali_c55_params_awb_gains); + params->data_size += sizeof(struct mali_c55_params_awb_gains); + + struct mali_c55_params_sensor_off_preshading *blc = + (struct mali_c55_params_sensor_off_preshading *)data; + + blc->header.type = MALI_C55_PARAM_BLOCK_SENSOR_OFFS; + blc->header.flags |= V4L2_ISP_PARAMS_FL_BLOCK_ENABLE; + blc->header.size = sizeof(struct mali_c55_params_sensor_off_preshading); + + blc->chan00 = 51200; + blc->chan01 = 51200; + blc->chan10 = 51200; + blc->chan11 = 51200; + + params->data_size += sizeof(struct mali_c55_params_sensor_off_preshading); + +Arm Mali-C55 uAPI data types +============================ + +.. kernel-doc:: include/uapi/linux/media/arm/mali-c55-config.h |