Binding UART4 with a Linux tty device on i.MX 8M Plus EVK

[kkobayas]

The i.MX 8M Plus applications processor has four UART ports and I know typically UART2 is for debugging Linux working on the Cortex-A53 core and UART4 is for debugging realtime OS working on the Cortex-M7 core on the EVK board according to the hardware user's guide.

Is it possible to bind UART4 with a Linux tty device and use it for communication between the EVK board and a host PC as well as UART2?

I don't mind if the kernel code such as device driver and dts files is changed to achieve this.

The i.MX Yocto recipe version I'm using is lf-6.1.22-2.0.0.

[JosephAtNXP · Accepted solution]

Hi,

Thank you for your interest in NXP Semiconductor products,

It is possible, you can do it in EVK and in your custom HW. As EVK connects UART4 to UART to USB bridge, if you don't run Cortex-M7 code (or run it allocating debug UART to another instance), you can allocate Linux debug UART to UART4.

I wrote a document for i.MX 9 series, that can be easily applied to i.MX 8M series since they also use ATF, U-boot and Linux. The document would be transparent, using the proper UART base addresses.

Regards