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Diffstat (limited to 'Documentation/media/v4l-drivers/ipu3.rst')
| -rw-r--r-- | Documentation/media/v4l-drivers/ipu3.rst | 53 |
1 files changed, 45 insertions, 8 deletions
diff --git a/Documentation/media/v4l-drivers/ipu3.rst b/Documentation/media/v4l-drivers/ipu3.rst index c9f780404eee..e4904ab44e60 100644 --- a/Documentation/media/v4l-drivers/ipu3.rst +++ b/Documentation/media/v4l-drivers/ipu3.rst @@ -265,19 +265,56 @@ below. yavta -w "0x009819A1 1" /dev/v4l-subdev7 -RAW Bayer frames go through the following ImgU pipeline HW blocks to have the +Certain hardware blocks in ImgU pipeline can change the frame resolution by +cropping or scaling, these hardware blocks include Input Feeder(IF), Bayer Down +Scaler (BDS) and Geometric Distortion Correction (GDC). +There is also a block which can change the frame resolution - YUV Scaler, it is +only applicable to the secondary output. + +RAW Bayer frames go through these ImgU pipeline hardware blocks and the final processed image output to the DDR memory. -RAW Bayer frame -> Input Feeder -> Bayer Down Scaling (BDS) -> Geometric -Distortion Correction (GDC) -> DDR +.. kernel-figure:: ipu3_rcb.svg + :alt: ipu3 resolution blocks image -The ImgU V4L2 subdev has to be configured with the supported resolutions in all -the above HW blocks, for a given input resolution. + IPU3 resolution change hardware blocks + +**Input Feeder** + +Input Feeder gets the Bayer frame data from the sensor, it can enable cropping +of lines and columns from the frame and then store pixels into device's internal +pixel buffer which are ready to readout by following blocks. + +**Bayer Down Scaler** + +Bayer Down Scaler is capable of performing image scaling in Bayer domain, the +downscale factor can be configured from 1X to 1/4X in each axis with +configuration steps of 0.03125 (1/32). +**Geometric Distortion Correction** + +Geometric Distortion Correction is used to performe correction of distortions +and image filtering. It needs some extra filter and envelop padding pixels to +work, so the input resolution of GDC should be larger than the output +resolution. + +**YUV Scaler** + +YUV Scaler which similar with BDS, but it is mainly do image down scaling in +YUV domain, it can support up to 1/12X down scaling, but it can not be applied +to the main output. + +The ImgU V4L2 subdev has to be configured with the supported resolutions in all +the above hardware blocks, for a given input resolution. For a given supported resolution for an input frame, the Input Feeder, Bayer -Down Scaling and GDC blocks should be configured with the supported resolutions. -This information can be obtained by looking at the following IPU3 ImgU -configuration table. +Down Scaler and GDC blocks should be configured with the supported resolutions +as each hardware block has its own alignment requirement. + +You must configure the output resolution of the hardware blocks smartly to meet +the hardware requirement along with keeping the maximum field of view. +The intermediate resolutions can be generated by specific tool and this +information can be obtained by looking at the following IPU3 ImgU configuration +table. https://chromium.googlesource.com/chromiumos/overlays/board-overlays/+/master |