topic soft reset in the imx6ull processor in i.MX Processors

soft reset in the imx6ull processor

Embedded-world — Thu, 07 Mar 2024 10:18:17 GMT

Dear Experts,

I'm working with Kernel 6.1.1 for a custom SOM with an EVB featuring the iMX6ULL processor. Currently, as per our EVB, we're not utilizing the hard reset (there is no external pin for watchdog1/2/3). Therefore, I'm seeking guidance on how to trigger the watchdog for the RESET switch soft/automatically/internally during reboot time.

I've posted several times regarding this issue, but I haven't received a proper response yet. Could someone please help me with this matter?

How do I configure the watchdog in the dts file for soft reset switch?
Which watchdog would support soft reset for reboot?
How can I verify the proper initialization node in the dts file?
Could you provide some solution examples for the above issue?

Best Regards,

Ravikumar

Re: soft reset in the imx6ull processor

Zhiming_Liu — Mon, 11 Mar 2024 04:19:26 GMT

For watchdog test, you can refer this userspace demo :

https://github.com/nxp-imx/imx-test/tree/lf-5.15.32_2.0.0/test/wdog

For dts, please refer Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.yaml

fsl,ext-reset-output: $ref: /schemas/types.yaml#/definitions/flag description: | If present, the watchdog device is configured to assert its external reset (WDOG_B) instead of issuing a software reset.

You should configure dts like this:

&wdog1 { status = "okay"; }; &wdog2 { status = "okay"; }; &wdog3 { status = "okay"; };

Then use wdt_driver_test program to trigger watchdog.

Best Regards

Zhiming

Re: soft reset in the imx6ull processor

Embedded-world — Mon, 11 Mar 2024 06:50:05 GMT

Hi @Zhiming_Liu

Thanks for your inputs.

is that possible to do software reset instead of hardware external-pin reset ?

Re: soft reset in the imx6ull processor

Zhiming_Liu — Mon, 11 Mar 2024 08:00:25 GMT

If fsl,ext-reset-output present, the watchdog device is configured to assert its external reset (WDOG_B) instead of issuing a software reset. So if you don't add this flag, the driver will issue software reset

Best Regards
Zhiming

Re: soft reset in the imx6ull processor

Embedded-world — Mon, 11 Mar 2024 11:19:39 GMT

Hi Zhiming_Liu.

I've asserted the external reset (WDOG_B) for watchdog1 in the dts file. However, despite this configuration, When I press the reset switch on my board, the reboot is not occurring. I've tried initiating the reboot using the command 'reboot' in minicom terminal emulator,

So How can I troubleshoot this issue? Also, What could be the reason for the reset switch not triggering the reboot, even though I've used the watchdog structure & having properly designed the board?

Thanks & Regards,
Ravikumar

Re: soft reset in the imx6ull processor

Zhiming_Liu — Tue, 12 Mar 2024 05:48:53 GMT

Can you share your dts setting?

Re: soft reset in the imx6ull processor

Embedded-world — Tue, 12 Mar 2024 06:37:14 GMT

Hi Zhiming_Liu

This was the watchdoog configuration in the dts file:

&wdog1 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_wdog>;
fsl,ext-reset-output;
status = "okay";
};

pinctrl_wdog: wdoggrp {
fsl,pins = <
MX6UL_PAD_LCD_RESET__WDOG1_WDOG_ANY 0x30b0
>;
};

also PFA below with full dts file.

Thank you & Regards,
Ravikumar

Re: soft reset in the imx6ull processor

Zhiming_Liu — Tue, 12 Mar 2024 07:18:39 GMT

Hi @Embedded-world

Can you also share your reset design?

Thanks& Besr Regards

Zhiming