maaxboard-mini linux watchdog can not reboot but hang on(freeze) after time out,how can I do?

[gonewithwind-peter]

hi all,

I asked  a question to add watchdog in maaxboard and maaxboard-mini before here :

https://community.nxp.com/t5/i-MX-Processors/imx8m-maaxboard-and-maaxboar-min-how-to-enable-watch-do...

for maaxboard , code 

./autorun-wdog.sh and ./wdt_driver_test.out 2 1 0 works well

and I use  ./wdt_driver_test.out 5 10 0 , after time out ,the linux will reboot. that makes sure the watchdog work well.

but for maaxboard-mini:

first I modified the dtb to add the watchdog device and make ./autorun-wdog.sh work well, I can find :

ls /dev/watchdog*
/dev/watchdog /dev/watchdog0

but when I run ./wdt_driver_test.out 5 10 0  , after time out ,the linux is hang on(freeze)   and not reboot!

what 's wrong with it?

one of my questions is :

is there a connection between watchdog  pin(MX8MM_IOMUXC_GPIO1_IO02_WDOG1_WDOG_B) from microprocessor and reset chip? so that after wathcdog time out, the pin can reset the microprocessor? I remember the watchdog is in side the processor , do not need a outside pin ,right?

Thank you very much.

attached is my watchdog dts patch partial:

+++ patch/arch/arm64/boot/dts/freescale/maaxboard-mini.dtsi 2022-06-08 14:01:05.077745490 -0400
@@ -224,6 +224,12 @@
>;
};

+ pinctrl_wdog: wdoggrp {
+ fsl,pins = <
+ MX8MM_IOMUXC_GPIO1_IO02_WDOG1_WDOG_B 0xc6
+ >;
+ };
+
pinctrl_wlan_gpio: usdhc2grpwlan {
fsl,pins = <
MX8MM_IOMUXC_SD2_RESET_B_GPIO2_IO19 0x41 /* WL_REG_ON */
@@ -498,6 +504,14 @@
};
};

+&wdog1 {
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_wdog>;
+ fsl,ext-reset-output;
+ status = "okay";
+};
+
+
&A53_0 {
arm-supply = <&buck2_reg>;
};

[gonewithwind-peter]

any help?

yocto sumo(kernel 4.14 and yocto zeus( kernel 5.1)  have the same issue.

sh-4.4# /home/myuser/wdt_driver_test.out 10 15 0

---- Running < /home/myuser/wdt_driver_test.out > test ----

Starting wdt_driver (timeout: 10, sleep: 15, test: ioctl)
Trying to set timeout value=10 seconds
The actual timeout was set to 10 seconds
Now reading back -- The timeout is 10 seconds

--- not reboot but hang on(freeze) after time out