media: docs: move uAPI book to userspace-api/media

Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee3862 ("docs: Create a user-space API guide").

As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.

Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 104 insertions, 0 deletions

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-meta-intel-ipu3.rst b/Documentation/userspace-api/media/v4l/pixfmt-meta-intel-ipu3.rst
new file mode 100644
index 000000000000..97a9a2925671
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/pixfmt-meta-intel-ipu3.rst
@@ -0,0 +1,104 @@
+.. This file is dual-licensed: you can use it either under the terms
+.. of the GPL 2.0 or the GFDL 1.1+ license, at your option. Note that this
+.. dual licensing only applies to this file, and not this project as a
+.. whole.
+..
+.. a) This file is free software; you can redistribute it and/or
+..    modify it under the terms of the GNU General Public License version
+..    2.0 as published by the Free Software Foundation.
+..
+..    This file is distributed in the hope that it will be useful,
+..    but WITHOUT ANY WARRANTY; without even the implied warranty of
+..    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+..    GNU General Public License version 2.0 for more details.
+..
+.. Or, alternatively,
+..
+.. b) Permission is granted to copy, distribute and/or modify this
+..    document under the terms of the GNU Free Documentation License,
+..    Version 1.1 or any later version published by the Free Software
+..    Foundation, with no Invariant Sections, no Front-Cover Texts
+..    and no Back-Cover Texts. A copy of the license is included at
+..    Documentation/userspace-api/media/fdl-appendix.rst.
+..
+.. TODO: replace it to GPL-2.0 OR GFDL-1.1-or-later WITH no-invariant-sections
+
+.. _v4l2-meta-fmt-params:
+.. _v4l2-meta-fmt-stat-3a:
+
+******************************************************************
+V4L2_META_FMT_IPU3_PARAMS ('ip3p'), V4L2_META_FMT_IPU3_3A ('ip3s')
+******************************************************************
+
+.. ipu3_uapi_stats_3a
+
+3A statistics
+=============
+
+The IPU3 ImgU 3A statistics accelerators collect different statistics over
+an input Bayer frame. Those statistics are obtained from the "ipu3-imgu [01] 3a
+stat" metadata capture video nodes, using the :c:type:`v4l2_meta_format`
+interface. They are formatted as described by the :c:type:`ipu3_uapi_stats_3a`
+structure.
+
+The statistics collected are AWB (Auto-white balance) RGBS (Red, Green, Blue and
+Saturation measure) cells, AWB filter response, AF (Auto-focus) filter response,
+and AE (Auto-exposure) histogram.
+
+The struct :c:type:`ipu3_uapi_4a_config` saves all configurable parameters.
+
+.. code-block:: c
+
+	struct ipu3_uapi_stats_3a {
+		struct ipu3_uapi_awb_raw_buffer awb_raw_buffer;
+		struct ipu3_uapi_ae_raw_buffer_aligned ae_raw_buffer[IPU3_UAPI_MAX_STRIPES];
+		struct ipu3_uapi_af_raw_buffer af_raw_buffer;
+		struct ipu3_uapi_awb_fr_raw_buffer awb_fr_raw_buffer;
+		struct ipu3_uapi_4a_config stats_4a_config;
+		__u32 ae_join_buffers;
+		__u8 padding[28];
+		struct ipu3_uapi_stats_3a_bubble_info_per_stripe stats_3a_bubble_per_stripe;
+		struct ipu3_uapi_ff_status stats_3a_status;
+	};
+
+.. ipu3_uapi_params
+
+Pipeline parameters
+===================
+
+The pipeline parameters are passed to the "ipu3-imgu [01] parameters" metadata
+output video nodes, using the :c:type:`v4l2_meta_format` interface. They are
+formatted as described by the :c:type:`ipu3_uapi_params` structure.
+
+Both 3A statistics and pipeline parameters described here are closely tied to
+the underlying camera sub-system (CSS) APIs. They are usually consumed and
+produced by dedicated user space libraries that comprise the important tuning
+tools, thus freeing the developers from being bothered with the low level
+hardware and algorithm details.
+
+.. code-block:: c
+
+	struct ipu3_uapi_params {
+		/* Flags which of the settings below are to be applied */
+		struct ipu3_uapi_flags use;
+
+		/* Accelerator cluster parameters */
+		struct ipu3_uapi_acc_param acc_param;
+
+		/* ISP vector address space parameters */
+		struct ipu3_uapi_isp_lin_vmem_params lin_vmem_params;
+		struct ipu3_uapi_isp_tnr3_vmem_params tnr3_vmem_params;
+		struct ipu3_uapi_isp_xnr3_vmem_params xnr3_vmem_params;
+
+		/* ISP data memory (DMEM) parameters */
+		struct ipu3_uapi_isp_tnr3_params tnr3_dmem_params;
+		struct ipu3_uapi_isp_xnr3_params xnr3_dmem_params;
+
+		/* Optical black level compensation */
+		struct ipu3_uapi_obgrid_param obgrid_param;
+	};
+
+Intel IPU3 ImgU uAPI data types
+===============================
+
+.. kernel-doc:: drivers/staging/media/ipu3/include/intel-ipu3.h