Cannot install watchdog timeout on STM32WB

[r2r0]

Describe the bug iwdg_stm32_install_timeout does not return because it is stuck inside while (LL_IWDG_IsReady(iwdg) == 0) loop. It looks like k_uptime_get_32 returns the same value for every call.

Please also mention any information which could help others to understand the problem you're facing:

• STM32WB55 clocked by PLL (based on HSE), with enabled tickless kernel (LPTIMER with LSE).
• CONFIG_WDT_DISABLE_AT_BOOT is enabled.
• After adding 3 NOP instruction to (mentioned above) while loop timeout is properly detected.
• For some reasons busy timeout polling with k_uptime_get_32 does not work well.

To Reproduce Steps to reproduce the behavior: Build with IWDG enabled and with CONFIG_WDT_DISABLE_AT_BOOT configuration option set. Try to run application.

Expected behavior iwdg_stm32_install_timeout should return with -EINVAL error.

Impact showstopper

Logs and console output

Environment (please complete the following information):

• OS: Linux
• Toolchain Zephyr SDK, 0.14.1
• Commit SHA d92e3b88bacc6e6fc1b6222421ef4accdf2d574e

Additional context During call to iwdg_stm32_install_timeout the IWDG is disabled because LL_IWDG_Enable was never called before and then LL_IWDG_IsReady will always return 0. LL_IWDG_Enable was not called before because of CONFIG_WDT_DISABLE_AT_BOOT is set. It means that present implementation may be incorrect because LL_IWDG_Enable will be called during wdt_setup which (according to documentation) will happen after call to wdt_install_timeout.

[FRASTM]

@r2r0 could you please check if PR https://github.com/zephyrproject-rtos/zephyr/pull/44972 helps

[r2r0]

Thanks @FRASTM - in fact this PR removes the trigger of described problem. After applying #44972 CPU leaves the while loop and the timeout hangout is avoided but it is still present.

[FRASTM]

When you build the samples/subsys/task_wdt with CONFIG_WDT_DISABLE_AT_BOOT=n (by default in the prj.conf the CONFIG_WDT_DISABLE_AT_BOOT is 'y') the timeout is installed during the initialisation of the device, with the same sequence as in _installtimeout You get :

*** Booting Zephyr OS build zephyr-v3.0.0-3100-g6c4c7e87f76*
Task watchdog sample application.                                               
Main thread still alive...                                                      
Control thread started.                                                         
Main thread still alive...                                                      
Main thread still alive...                                                      
Main thread still alive...                                                      
Control thread getting stuck...                                                 
Task watchdog channel 1 callback, thread: control                               
Resetting device...

[r2r0]

Unfortunately blocking of while loop is visible only very rarely when console and debugger (even without breakpoints installed) are connected. When it happens then it looks that also LPTIM ISR is not working. After power cycling problem disappears (usually) for long time. Because I am not able to consistently reproduce problem then I will close this issue for now. BTW> @FRASTM would it be possible to advance merging of the #44972, please.