i.MX ProcessorsのトピックRe: When we use UART4 on IMX8MM form Linux User Space, device will be kernel panic.

When we use UART4 on IMX8MM form Linux User Space, device will be kernel panic.

charleshuang — Tue, 19 Dec 2023 14:20:08 GMT

Hi NXP Team

In Yocto 4.0 5.15.52. Device is iMX8MM.

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/How-to-use-UART4-on-iMX8M-from-Linux-User-Space/ta-p/1762038

Our customer and My team follow the nxp solution to try use the UART4 on iMX8MM form Linux user space.

But device will be kernel panic.

https://github.com/ADVANTECH-Corp/meta-advantech2/commit/7acd89522542ba2bacdf94121361b140d9ee3793

https://github.com/ADVANTECH-Corp/meta-advantech2/commit/1ff67f71a5eb40fe35e902ce52ec59e8b504413a

About the UART4.

Yocto 3.0 is Pass, but Yocto 4.0_5.15.52 is kernel panic.

Do you have any advice?

Re: When we use UART4 on IMX8MM form Linux User Space, device will be kernel panic.

AldoG — Tue, 19 Dec 2023 21:25:02 GMT

Hello,

I see that the changes made to ATF looks correct, even I would say that the changes made by @Chavira are mean to latest releases so if used in old releases some tunning may be needed.

I do not see the device tree changes, are those in place?

Best regards,
Aldo.

Re: When we use UART4 on IMX8MM form Linux User Space, device will be kernel panic.

charleshuang — Wed, 20 Dec 2023 07:28:09 GMT

Hi @AldoG

We find the solution and can use the UART4 from Linux User Space

Thanks for your help.

Re: When we use UART4 on IMX8MM form Linux User Space, device will be kernel panic.

Chirag — Tue, 02 Apr 2024 10:57:58 GMT

Hello,

I am also running into exact same problem. I am on kernel 6.1.22 [imx8mm]. I have build custom imx-boot with updated changes of uart4 in imx-atf firmware as described here
https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/How-to-use-UART4-on-iMX8M-from-Linux-User-Space/ta-p/1762038
Although its still not working and having a kernel panic error.
the kernel works fine though when uart4 is disabled in dtb. Its defined as:

&uart4 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart4>;
/delete-property/ dmas;
/delete-property/ dmas-names;
fsl,dte-mode;
status = "okay";
};

pinctrl_uart4: uart4grp {
fsl,pins = <
MX8MM_IOMUXC_UART4_RXD_UART4_DCE_RX 0x140
MX8MM_IOMUXC_UART4_TXD_UART4_DCE_TX 0x140
>;
};

Anything I am missing or any advice on this ?

Re: When we use UART4 on IMX8MM form Linux User Space, device will be kernel panic.

Chirag — Tue, 02 Apr 2024 12:54:36 GMT

Hello, @charleshuang

Can you provide any information regarding this ? I am having an exact same issue. I have updated imx-atf changes though.

Thank You.