TDA4VM: Watchdog failed to reboot system after successful reboot system for dozens of times

Sean%20Chuang1

Prodigy 20 points

Part Number: TDA4VM

Tool/software:

Hi there,

The steps that we used for watchdog are as follow:

1.Enable watchdog in the chip with a 30 Sec timeout period.

2.Ping the watchdog within 30 Sec when SW is functional.

3.When the "reboot" Linux system call is issued from user space the kernel driver will do the following tasks

3-1 A callback function for the 'reboot' command will be invoked which will write data to the watchdog HW module during its "windows closed period" and this should trigger system reboot immediately.

3-2 Stop pinging the watchdog after receiving the "reboot" command.

We proceeded step 1~2 for a few moment then performing step 3 to reboot the system.

We found that our system could be rebooted dozens of times (e.g. 15 times) and finally it did not be rebooted.

I think if step 3-1 didn't make it reboot then step 3-2 would also cause system to reboot finally.

Thanks,

Sean

4 months ago

0 Keerthy J 4 months ago

TI__Guru**** 162280 points

Hello Sean,

What's the use case you are trying to test here?

Watchdog reset stops working after a dozen times? Is that the failing test case? Also which SDK is being used?

Best Regards,

Keerthy

0 Sean%20Chuang1 4 months ago in reply to Keerthy J

Prodigy 20 points

Hi Keerthy,

We try to link reboot system call to use WDT to reboot our system and this is our use case.

As I mentioned in the previous mail about the steps for doing this and it works a dozen times therefore I think the steps to enable and trigger it to reboot our system should be ok.

My question is why it failed after many successful reboots with the same procedure?

I used SDK0804.

Thanks,

Sean

0 Keerthy J 4 months ago in reply to Sean%20Chuang1

TI__Guru**** 162280 points

Hello Sean,

Reboot call itself finally reaches ATF code and resets the system.

Can you try just the reboot multiple times and check if that works greater than a dozen times?

Best Regards,

Keerthy

0 Sean%20Chuang1 4 months ago in reply to Keerthy J

Prodigy 20 points

Hello Keerth,

Reboot multiple times is ok.
But reboot too many times could fail.

Thanks,

Sean

0 Keerthy J 4 months ago in reply to Sean%20Chuang1

TI__Guru**** 162280 points

Hi Sean,

Sean%20Chuang1 said:
Reboot multiple times is ok.
But reboot too many times could fail.

What I am asking is to test reboot without any watchdog involvement. Just reboot command should reset the board without watchdog timeout.
I want to know if that is rebooting board stably Vs Watchdog rebooting the board.

Hope I am clear.

- Keerthy

0 Sean%20Chuang1 4 months ago in reply to Keerthy J

Prodigy 20 points

Hello Keerthy,

I tested reboot without watchdog involvement for multiple times and the reboot results are ok.

Thanks,

Sean

0 Keerthy J 4 months ago in reply to Sean%20Chuang1

TI__Guru**** 162280 points

Sean,

Thanks! So do you need watchdog to come in the way? Why not use reboot command the way it is to reset the system?

- Keerthy

0 Sean%20Chuang1 4 months ago in reply to Keerthy J

Prodigy 20 points

Hello Keerthy,

I think WDT could be more likely a HW reset(could be something like to press a reset button on the board) but I guess reboot command here without WDT involvement could be only reset on SW level(could be only to make SW restart).

I did several reboot tests via HW WDT and found that reboot would fail at the 15th. I wonder if your ATF or some settings would constrain the reboot times.

We tried this test for three times and it seems all stop at the 15th reboot.

Regards,

Sean

0 Keerthy J 4 months ago in reply to Sean%20Chuang1

TI__Guru**** 162280 points

Hi Sean,

Sean%20Chuang1 said:
We tried this test for three times and it seems all stop at the 15th reboot.

Thanks for the details. This seems like PMIC's limit. The watchdog reset finally triggers reset via PMIC.

So resetting the PMIC might be having the limit of 15 times. I will loop in our PMIC expert.

- Keerthy

0 John Tu 3 months ago in reply to Keerthy J

Prodigy 210 points

Hi Keerthy,
This is an important issue, is there any progress?

0 Keerthy J 3 months ago in reply to John Tu

TI__Guru**** 162280 points

Hi John,

It is assigned to PMIC expert. I will let our PMIC expert comment on that.

- Keerthy

0 PYTsai 3 months ago in reply to Keerthy J

TI__Genius 11475 points

Hi Keerthy,

Which PMIC shold we look into for this issue ?

0 Michael Gambrill 3 months ago in reply to Keerthy J

TI__Mastermind 25165 points

Keerthy J said:
So resetting the PMIC might be having the limit of 15 times. I will loop in our PMIC expert.

For the catalog TDA4 attached PMICs, a watchdog induced warm reset increments the recovery counter. Once the recovery limit is reached, 15 for most devices, the PMIC will execute an orderly shutdown and stay shutdown.

In addition to warm resets, any event that causes the PMIC to pass through the Safe Recovery state will increment the recovery counter.

The recovery count is found in register 0x83.

The recovery count threshold is found in register 0x84. You can clear the current count by writing 1 to bit 4 of this register. It is recommended that software clear the recovery counter after a successful boot.

Processors

Processors forum

TDA4VM: Watchdog failed to reboot system after successful reboot system for dozens of times