TDA4VM: TDA4VM: Output video on CSI TX interface

Szymon Mielczarek

Part Number: TDA4VM

Hi,

SDK: Processor SDK Linux J721e (08.04)

We need to send a captured video (from other interface than CSI) plus some graphics overlays to CSI TX interface.
The Display Subsystem (DSS) provides HW mechanisms for overlays, scaling, cropping and color space conversion but CSI interface belongs to Camera Subsystem. Is it possible to process the video data through DSS and then output it to CSI TX?

Are there any reference examples on how to handle such use case?
Generally, what kind of support does SDK 08.04 provide for CSI output?

From the low level perspective, I understand that we need to indicate a memory from which the CSI controller can stream out video data (via DMA interface).
SDK documentation only says about CSI RX:
https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-jacinto7/08_04_00_11/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Camera/CSI2RX.html?highlight=csi

I see there is a kernel driver for Cadence MIPI-CSI2 TX Controller:
cdns-csi2tx (CONFIG_VIDEO_CADENCE_CSI2TX)

BR,

Szymon

over 3 years ago

0 Brijesh Jadav over 3 years ago

TI__Guru**** 477705 points

Hi Szymon Mielczarek,

Can you please refer to below FAQ?

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1007456/faq-tda4vm-how-to-use-dss-m2m-for-format-conversion

Essentially, you could use DSS M2M path for format conversion, scaling, cropping etc.. and then output of DSS M2M path can be fed to CSITX..

This driver currently does not support blending, so we cannot use two images from memory and blend them. This is not supported in the current driver..

Regards,

Brijesh

0 Szymon Mielczarek over 2 years ago in reply to Brijesh Jadav

Prodigy 100 points

Hi Brijesh,

Thank you.

Are there any reference examples or documentation for Linux SDK (not RTOS/Vision) on how to use the write-back pipeline in M2M mode (possibly to feed CSI_TX)?

I was also asking about reference examples for CSI TX. As I mentioned, for CSI RX, there are even some userspace utilities to interact with the driver but nothing about TX interface.

BR,

Szymon

0 Brijesh Jadav over 2 years ago in reply to Szymon Mielczarek

TI__Guru**** 477705 points

Hi Szymon Mielczarek,

I really dont think DSS write back path in M2M mode is supported in the Linux. This is supported only on RTOS.

Also i doubt that even CSITX is supported on Linux. Linux supports CSIRX and DSS. CSITX and DSS Write back paths are not supported in Linux.

Regards,

Brijesh

0 Szymon Mielczarek over 2 years ago in reply to Brijesh Jadav

Prodigy 100 points

Hi Brijesh,

Just to clarify. You are saying that even though CSI TX and WB pipeline are supported by TDA4VM (J721e) HW (according to TRM) there is no support for these features in Linux SDK, right? Maybe apart from mentioned low level driver (cdns-csi2tx (CONFIG_VIDEO_CADENCE_CSI2TX)).

BR,

Szymon

0 Brijesh Jadav over 2 years ago in reply to Szymon Mielczarek

TI__Guru**** 477705 points

Hi,

Yes, they are supported in HW and also are supported on RTOS ie on R5F, but not supported on Linux.

Regards,

Brijesh

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TDA4VM: TDA4VM: Output video on CSI TX interface