Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 183 insertions, 0 deletions

diff --git a/Documentation/media/v4l-drivers/qcom_camss.rst b/Documentation/media/v4l-drivers/qcom_camss.rst
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+.. include:: <isonum.txt>
+
+Qualcomm Camera Subsystem driver
+================================
+
+Introduction
+------------
+
+This file documents the Qualcomm Camera Subsystem driver located under
+drivers/media/platform/qcom/camss.
+
+The current version of the driver supports the Camera Subsystem found on
+Qualcomm MSM8916/APQ8016 and MSM8996/APQ8096 processors.
+
+The driver implements V4L2, Media controller and V4L2 subdev interfaces.
+Camera sensor using V4L2 subdev interface in the kernel is supported.
+
+The driver is implemented using as a reference the Qualcomm Camera Subsystem
+driver for Android as found in Code Aurora [#f1]_ [#f2]_.
+
+
+Qualcomm Camera Subsystem hardware
+----------------------------------
+
+The Camera Subsystem hardware found on 8x16 / 8x96 processors and supported by
+the driver consists of:
+
+- 2 / 3 CSIPHY modules. They handle the Physical layer of the CSI2 receivers.
+  A separate camera sensor can be connected to each of the CSIPHY module;
+- 2 / 4 CSID (CSI Decoder) modules. They handle the Protocol and Application
+  layer of the CSI2 receivers. A CSID can decode data stream from any of the
+  CSIPHY. Each CSID also contains a TG (Test Generator) block which can generate
+  artificial input data for test purposes;
+- ISPIF (ISP Interface) module. Handles the routing of the data streams from
+  the CSIDs to the inputs of the VFE;
+- 1 / 2 VFE (Video Front End) module(s). Contain a pipeline of image processing
+  hardware blocks. The VFE has different input interfaces. The PIX (Pixel) input
+  interface feeds the input data to the image processing pipeline. The image
+  processing pipeline contains also a scale and crop module at the end. Three
+  RDI (Raw Dump Interface) input interfaces bypass the image processing
+  pipeline. The VFE also contains the AXI bus interface which writes the output
+  data to memory.
+
+
+Supported functionality
+-----------------------
+
+The current version of the driver supports:
+
+- Input from camera sensor via CSIPHY;
+- Generation of test input data by the TG in CSID;
+- RDI interface of VFE
+
+  - Raw dump of the input data to memory.
+
+    Supported formats:
+
+    - YUYV/UYVY/YVYU/VYUY (packed YUV 4:2:2 - V4L2_PIX_FMT_YUYV /
+      V4L2_PIX_FMT_UYVY / V4L2_PIX_FMT_YVYU / V4L2_PIX_FMT_VYUY);
+    - MIPI RAW8 (8bit Bayer RAW - V4L2_PIX_FMT_SRGGB8 /
+      V4L2_PIX_FMT_SGRBG8 / V4L2_PIX_FMT_SGBRG8 / V4L2_PIX_FMT_SBGGR8);
+    - MIPI RAW10 (10bit packed Bayer RAW - V4L2_PIX_FMT_SBGGR10P /
+      V4L2_PIX_FMT_SGBRG10P / V4L2_PIX_FMT_SGRBG10P / V4L2_PIX_FMT_SRGGB10P /
+      V4L2_PIX_FMT_Y10P);
+    - MIPI RAW12 (12bit packed Bayer RAW - V4L2_PIX_FMT_SRGGB12P /
+      V4L2_PIX_FMT_SGBRG12P / V4L2_PIX_FMT_SGRBG12P / V4L2_PIX_FMT_SRGGB12P).
+    - (8x96 only) MIPI RAW14 (14bit packed Bayer RAW - V4L2_PIX_FMT_SRGGB14P /
+      V4L2_PIX_FMT_SGBRG14P / V4L2_PIX_FMT_SGRBG14P / V4L2_PIX_FMT_SRGGB14P).
+
+  - (8x96 only) Format conversion of the input data.
+
+    Supported input formats:
+
+    - MIPI RAW10 (10bit packed Bayer RAW - V4L2_PIX_FMT_SBGGR10P / V4L2_PIX_FMT_Y10P).
+
+    Supported output formats:
+
+    - Plain16 RAW10 (10bit unpacked Bayer RAW - V4L2_PIX_FMT_SBGGR10 / V4L2_PIX_FMT_Y10).
+
+- PIX interface of VFE
+
+  - Format conversion of the input data.
+
+    Supported input formats:
+
+    - YUYV/UYVY/YVYU/VYUY (packed YUV 4:2:2 - V4L2_PIX_FMT_YUYV /
+      V4L2_PIX_FMT_UYVY / V4L2_PIX_FMT_YVYU / V4L2_PIX_FMT_VYUY).
+
+    Supported output formats:
+
+    - NV12/NV21 (two plane YUV 4:2:0 - V4L2_PIX_FMT_NV12 / V4L2_PIX_FMT_NV21);
+    - NV16/NV61 (two plane YUV 4:2:2 - V4L2_PIX_FMT_NV16 / V4L2_PIX_FMT_NV61).
+    - (8x96 only) YUYV/UYVY/YVYU/VYUY (packed YUV 4:2:2 - V4L2_PIX_FMT_YUYV /
+      V4L2_PIX_FMT_UYVY / V4L2_PIX_FMT_YVYU / V4L2_PIX_FMT_VYUY).
+
+  - Scaling support. Configuration of the VFE Encoder Scale module
+    for downscalling with ratio up to 16x.
+
+  - Cropping support. Configuration of the VFE Encoder Crop module.
+
+- Concurrent and independent usage of two (8x96: three) data inputs -
+  could be camera sensors and/or TG.
+
+
+Driver Architecture and Design
+------------------------------
+
+The driver implements the V4L2 subdev interface. With the goal to model the
+hardware links between the modules and to expose a clean, logical and usable
+interface, the driver is split into V4L2 sub-devices as follows (8x16 / 8x96):
+
+- 2 / 3 CSIPHY sub-devices - each CSIPHY is represented by a single sub-device;
+- 2 / 4 CSID sub-devices - each CSID is represented by a single sub-device;
+- 2 / 4 ISPIF sub-devices - ISPIF is represented by a number of sub-devices
+  equal to the number of CSID sub-devices;
+- 4 / 8 VFE sub-devices - VFE is represented by a number of sub-devices equal to
+  the number of the input interfaces (3 RDI and 1 PIX for each VFE).
+
+The considerations to split the driver in this particular way are as follows:
+
+- representing CSIPHY and CSID modules by a separate sub-device for each module
+  allows to model the hardware links between these modules;
+- representing VFE by a separate sub-devices for each input interface allows
+  to use the input interfaces concurently and independently as this is
+  supported by the hardware;
+- representing ISPIF by a number of sub-devices equal to the number of CSID
+  sub-devices allows to create linear media controller pipelines when using two
+  cameras simultaneously. This avoids branches in the pipelines which otherwise
+  will require a) userspace and b) media framework (e.g. power on/off
+  operations) to  make assumptions about the data flow from a sink pad to a
+  source pad on a single media entity.
+
+Each VFE sub-device is linked to a separate video device node.
+
+The media controller pipeline graph is as follows (with connected two / three
+OV5645 camera sensors):
+
+.. _qcom_camss_graph:
+
+.. kernel-figure:: qcom_camss_graph.dot
+    :alt:   qcom_camss_graph.dot
+    :align: center
+
+    Media pipeline graph 8x16
+
+.. kernel-figure:: qcom_camss_8x96_graph.dot
+    :alt:   qcom_camss_8x96_graph.dot
+    :align: center
+
+    Media pipeline graph 8x96
+
+
+Implementation
+--------------
+
+Runtime configuration of the hardware (updating settings while streaming) is
+not required to implement the currently supported functionality. The complete
+configuration on each hardware module is applied on STREAMON ioctl based on
+the current active media links, formats and controls set.
+
+The output size of the scaler module in the VFE is configured with the actual
+compose selection rectangle on the sink pad of the 'msm_vfe0_pix' entity.
+
+The crop output area of the crop module in the VFE is configured with the actual
+crop selection rectangle on the source pad of the 'msm_vfe0_pix' entity.
+
+
+Documentation
+-------------
+
+APQ8016 Specification:
+https://developer.qualcomm.com/download/sd410/snapdragon-410-processor-device-specification.pdf
+Referenced 2016-11-24.
+
+APQ8096 Specification:
+https://developer.qualcomm.com/download/sd820e/qualcomm-snapdragon-820e-processor-apq8096sge-device-specification.pdf
+Referenced 2018-06-22.
+
+References
+----------
+
+.. [#f1] https://source.codeaurora.org/quic/la/kernel/msm-3.10/
+.. [#f2] https://source.codeaurora.org/quic/la/kernel/msm-3.18/