Commit 4147dca2 authored by Bingbu Cao's avatar Bingbu Cao Committed by Mauro Carvalho Chehab
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media: doc-rst: add more info for resolution change blocks in ipu3 



This patch add more details for the resolution change blocks
It can help the developer to understand the main resolution
change blocks in ImgU.

[sakari.ailus@linux.intel.com: Add new files to MAINTAINERS]

Signed-off-by: default avatarBingbu Cao <bingbu.cao@intel.com>
Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@kernel.org>
parent a4260ea4

Documentation/media/v4l-drivers/ipu3.rst

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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

Documentation/media/v4l-drivers/ipu3_rcb.svg

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MAINTAINERS

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F:	drivers/staging/media/ipu3/

F:	Documentation/media/uapi/v4l/pixfmt-meta-intel-ipu3.rst

F:	Documentation/media/v4l-drivers/ipu3.rst

F:	Documentation/media/v4l-drivers/ipu3_rcb.svg









INTEL IXP4XX QMGR, NPE, ETHERNET and HSS SUPPORT









M:	Krzysztof Halasa <khalasa@piap.pl>
































drivers/staging/media/ipu3/TODO



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  relevant. (Sakari)



















- IPU3 driver documentation (Laurent)









  Add diagram in driver rst to describe output capability.









  Comments on configuring v4l2 subdevs for CIO2 and ImgU.



















- uAPI documentation: