Linux/AM5718: AM5718 custom board interfacing with camera sensor

Hi,

Please provide a detailed description of your use case: hardware used, sensor type, USB used, hardware connections, Linux version, etc...

Hi,

We are using Custom AM5718 Board.
With Ti-Cal sensor driver on LInux version "Linux am57xx-evm 4.9.59-ga75d8e9305".
Sensor Type : CMOS sensor

Thanks,
Simit

Hi Simit,

I am confused. Are you using CSI-2 interface to bring the data in or USB interface? If USB interface, is it USB-2 or USB-3? Are you saying that you have a throughput need of 150 MBytes per sec from that particular interface?

Regards,
Manisha

Hi Manisha,

we captured image from the sensor which was connected on CSI-2 interface and transfer those captrured image data over USB-3.

we need the 150MBPS throughput of total process. [capturing data and sending over usb]

Thanks & Best Regards,

Simit

Hi Simit,

How many lanes of CAL interface are you using for capture? In 4-lanes mode, CAL interface should be able to handle up to 600 MBytes/sec. Check below link on CAL throughput.
processors.wiki.ti.com/.../Linux_Core_CAL_User's_Guide

I will get back on USB 3.0 write throughput on AM5718.

How is the captured data movement happening, once it is inside the AM57x DDR memory? Is there internal memcpy involved or are you using dmabuf to share the buffers between the drivers? Are you just passing through the CSI-2 captured image to USB driver or are you doing CPU processing of the captured data from CAL interface before writing it to the USB interface?

Regards,
Manisha

Hi Manisha,

Here i have attached complete flow of our project.This is what we are doing right now. And the speed is too slow.

So will you please guide us. To improve it.

Thanks,

Simit

Hi Simit,

USB 3.0 read throughput is 92 Mbytes/sec in Processor SDK 5.0, so you may be having a bottleneck there.

AM5718 has roughly 3000 MBytes/sec DDR throughput, so you should be okay from DDR access perspective.

The CPU processing can get bottleneck if the buffers they are reading/writing upon are non-cached operations. While you are allocating buffers from CMEM, make sure you enable the cache operations on those buffer. Also, try to avoid un-necessary mem-copies. You can directly operate on the V4L2 buffers. To share with other drivers, you can support dmabuf operations on the drivers.

Regards,
Manisha

Hi Manisha,

Thanks for support.

And what is the USB 3.0 write throughput?

Thanks,

Simit