AM62A7-Q1: Issue: MIPI CSI2 can't receive 4 cameras about 3M resolution (1920x1536) per unit with MIPI virtual channel.

Arthur Chen

Part Number: AM62A7-Q1
Other Parts Discussed in Thread: AM62A7

Tool/software:

Hello TI experts,

We met issue that we can't preview 4 cameras about 3M resolution (1920x1536) in the same time but 3 cameras about 3M resolution (1920x1536) in the same time can.

We also tried single previewing each camera about 3M resolution (1920x1536) with proper matching virtual channel (powered on and initialized one by one), and all of them are works.

How could we check the MIPI CSI2 status and adjust setting to make 4 cameras about 3M resolution (1920x1536) previewing in the same time working?

We already adjusted reserved C7 shared memory from 288MB to be 864MB, MIPI RX Clock 1.1 GHz and 4 lanes about MIPI CSI2 Data.

The enable_streams of v4l2_subdev_pad_ops called and working with g-streamer pipe setting but the video is not showing.

Customized board with AM62A7-Q1

TI SDK BSP version: V09_00_02

Linux version: 6.1.80

Total needed data: 3M x RAW10 x 30fps x 4 ports = 3.6 Gbps

Data loading per Lane : 900 Mbps

Needed data loading per Camera: 900 Mbps

11 months ago

0 Jianzhong Xu 11 months ago

TI__Guru 59715 points

Hello Arthur,

What serializer/deserializer are you using? The total data rate is 1920*1536*10*30*4=3.5Gbps. Taking into account the overhead due to blanking and CSI protocol, for example 20%, the data rate is 3.5Gbps*1.2=4.2Gbps. Make sure the deserializer is properly configured to support this data rate.

Regards,

Jianzhong

0 Arthur Chen 11 months ago in reply to Jianzhong Xu

Prodigy 40 points

Hello Jianzhong,

What serializer/deserializer are you using?

-> We are using DS90UB953 + DS90UB9724TRURRQ1

Looks like we need to reserve the MIPI CSI blanking bandwidth by speeding up MIPI CSI Clock from 1.2 GHz to 1.6GHz.

Is AM62A7 support MIPI CSI2 deskew in MIPI clock 1.6GHz ?

How could we enable MIPI CSI2 deskew setting? In device tree?

0 Jianzhong Xu 11 months ago in reply to Arthur Chen

TI__Guru 59715 points

Hi Arthur,

The DS90UB960 link frequency needs to be set to 800MHz: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62a7-sk-fusion.dtso?h=ti-linux-6.6.y#n65. When the link frequency is 800MHz, or Tx data rate is 1.6GHz, the UB960 will automatically send a deskew sequence: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/drivers/media/i2c/ds90ub960.c?h=ti-linux-6.6.y#n1757.

Regards,

Jianzhong

0 Arthur Chen 11 months ago in reply to Jianzhong Xu

Prodigy 40 points

Hello Jianzhong,

Our issue should be on the MIPI CSI2 connection between DS90UB9724TRURRQ1 & AM62A7 for 4 ports Virtual channel in the same time.

DS90UB960's setting is working ok and verified with camera preview one by one.

How could we enable MIPI CSI2 deskew setting for am62A7 & DS90UB9724TRURRQ1? In device tree?

0 Jianzhong Xu 11 months ago in reply to Arthur Chen

TI__Guru 59715 points

Hi Arthur,

As far as I know, nothing needs to be done at the CSI2 Rx side on AM62A7. If the deserializer is configured properly, it should automatically send a calibration (deskew) sequence and the CSI2 Rx on AM62A7 should be calibrated.

Can you lower the frame size for the cameras to reduce the data rate and see if you can stream with 4 cameras? This can help rule out other issues.

Thanks,

Jianzhong

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AM62A7-Q1: Issue: MIPI CSI2 can't receive 4 cameras about 3M resolution (1920x1536) per unit with MIPI virtual channel.