issue about imx6 uart dma

[宗標廖]

Hello Community

My customer uses BSP3.0.35_4.1.0 on i.mx6dl and they connected BT to UART4, and they enabled SDMA for UART4.

They found that when the BT chip is communicating with i.MX6, sometimes the Rx DMA of UART4 goes to stop. 

Could you give me some advice to resolve this problem?

Best Regards

ZongbiaoLiao

[igorpadykov]

Hi ZongbiaoLiao

please check attached Linux Manual Chapter 39
Universal Asynchronous Receiver/Transmitter (UART) Driver

If you want to use the DMA support for UART please also
enable the RTS/CTS for it. The DMA may be abnormal if you
do not enable the RTS/CTS.

Best regards
igor
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[宗標廖]

Hi igor

Thank you for you reply.

My customer used CTS/RTS. So is there any other possible reason?

Best Regards

ZongbiaoLiao

[igorpadykov]

Hi ZongbiaoLiao

since L3.0.35 uart driver was significantly changed, for example

refer to attached patches. So recommendation to migrate to more new kernels.

Best regards
igor

[宗標廖]

Hi igor

Thank you for offer me patches.

My customer's project is based on L3.0.35_4.1.0, now it is impossible(no time) to migrate to newer BSP.

Best Regards

ZongbiaoLiao

[igorpadykov]

Hi ZongbiaoLiao

L3.0.35_4.1.0 is old bsp and not supported in usual way,

it is removed from nxp bsps software page

i.MX 6 / i.MX 7 Series Software and Development Tool|NXP 

 its support provided by NXP Professional Services:

http://www.nxp.com/support/nxp-professional-services:PROFESSIONAL-SERVICE

Best regards
igor