Question, i.MX6SoliLite SDMA script for UART communication

[Aemj]

Dear team,

I would like to ask about SDMA script for i.MX6SoloLite.

My customer is facing the issue that missing data can be seen on UART communication using SDMA on their i.MX6SL board.

Sometimes interrupt for RX data could not occur on their system.

They think SDMA script has a bug and it is the cause of this issue.

The attached file is the SDMA script they are using and it is included in your platformSDK.

Could you show me whether such problem was seen on the past PlatformSDK?

And could you show me whether the difference exist between the attached file and the latest LinuxBSP?

Thanks,

Miyamoto

Original Attachment has been moved to: sdma_script_code_mx6sdl.zip

[Aemj]

Dear Jimmychan,

Thanks for your quick response.

> Are you using Linux BSP to test ?

Unfortunately, the customer does not use LinuxBSP for the test, they are using RTOS for the test.

The customer believes that this SDMA interrupt issue is the chip(i.MX6) specific problem.

Do you know whether such issue is known on i.MX6SL SDMA?

Thanks,

Miyamoto

[jimmychan]

We only support Linux and Android. It is better to contact your RTOS BSP provider to support this issue.

[Aemj]

Dear jimmychan,

Thanks for your support.

According to the customer’s investigation, the phenomenon occur only in the case that the data size is just the half of buffer-size.

And the issue does not occur if the data size is not just the half of buffer size.

Please let me know if you have any information on such phenomenon in the past experiences.

As I mentioned before, the above test was done on the customer’s environment(e.g. OS is RTOS).

And we will try to reproduce this issue on your LinuxBSP but it will take some more time.

Thanks,

Miyamoto

[weidong_sun]

Hello Miyamoto,

   I recommend customer uses the latest SDMA firmware released (should be ver3.0) in linux bsp 4.1.15. For PlatformSDK, we don't provide support for customer, and also it will not be updated in the fulture.

Regards,

Weidong

[Aemj]

Dear Weidong,

Thanks a lot for you support.

The SDMA firmware in LinuxBSP seems to be updated from the one in PlatformSDK.

Do you know what the difference is?

Thanks,

Miyamoto

[Aemj]

Dear Weidong,

The customer implemented SDMA script of LinuxBSP and the issue still occurs. 

Could you give your answer to the following asap?

In my customer’s lab, they saw the following phenomenon on SDMA of i.MX6SoloLite regarding to UART communication.

The issue is that SDMA could not respond to the interrupt from UART in case of certain combinations of SDMA’s buffer-size, UART RX packet size and Trigger size.

The following cases are seen on the customer’s lab.

(1)

- Trigger:16Bytes, BufferSize:64Bytes, PacketSize:32Bytes

 When transmit 1 packet to UART,

 - Interrupt does not be generated for the timeout from SDMA

- The Busy flag keeps being set in SDMA register

- In SDMA buffer, 32byte data is stored.

- Trigger:16Bytes, BufferSize:64Bytes, PacketSize:32Bytes

 When transmit 2 packet to UART,

 - one interrupt from SDMA is generated

(2)

- Trigger:16Bytes, BufferSize:128Bytes, PacketSize:64Bytes

 When transmit 1 packet to UART,

 - Interrupt does not be generated for the timeout from SDMA

- The Busy flag keeps being set in SDMA register

- In SDMA buffer, 64byte data is stored.

- Trigger:16Bytes, BufferSize:128Bytes, PacketSize:64Bytes

 When transmit 2 packet to UART,

 - one interrupt from SDMA is generated

The questions are;

(A)

Why the interrupt for timeout could not be generated, in the case of transmit the packet which size is half of buffer-size?

(B)

Are there any workaround for the above phenomenon?

Thanks,

Miyamoto

[jimmychan]

Are you using Linux BSP to test ? Is there any step to reproduce the issue?

[Aemj]

Dear team,

Sorry for hurrying you up but I  need the answer asap.

The customer is trying to re-implement the sdma script which is included in LinuxBSP into their software.

(Now the sdma script they are using is PlatformSDK base.)

But they need to know the information about the difference of sdam script between PlatformSDK and LinuxBSP.

Thanks,

Miyamoto