MfgTool with watchdog enabled

[mixa]

I have blown WDOG_ENABLE eFuse on SabreSD board to turn on the watchdog while device is in MFG mode. Changed the device tree for MFG to initialize wdog1 instead of wdog2 as this one is used telling by the manual.

The problem seems to be that initramfs for MFG does not have init process and watchdogd is not started (as it is part of the init) so wdog1 will not be serviceds. When I try to flash the board it resets when it starts writing the system image and I see that reset cause is WDOG.

How do I service the wdog1 in Mfg?

[igorpadykov]

Hi Mihailo

mfg tool uses the same linux as ordinary linux so wdogs should operate

in the same manner. SabreSD board uses GPIO_1 as wdog2 for board reset

so if it resets, seems wdog2 was not disabled and one can check GPIO_1

with oscilloscope. Also one can try to debug it using attached Linux Manual

Chapter 48 Watchdog (WDOG) Driver.

Best regards

igor

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[mixa]

Did anybody had the same problem? Is there any solution to this?

[mixa]

Hi Igor,

MfgTool does use the same kernel as ordinary linux or Android, but the ramdisk is not the same. I have unpacked initramfs from MfgTool and from Android and they are different. In MfgTool rdinit is set to linuxrc script and in Android to init process. Also the watchdogd service is in init process that runs on Android and there is no init in MfgTool ramdisk. I suppose that watchdog must be serviced when MfgTool runs also, as it is initialized but I do not understand which process does this in MfgTool ramdisk?

On the other hand, in the iMX manual it is written that WDOG_ENABLE fuse will activate WDOG1 and linux by default uses WDOG2. I have made changes to device tree for the MfgTool kernel to switch it to WDOG1 but I still get reset when flashing system image (I suppose as there is no activity on USB when running simg2img and writing sparse image the WDOG1 expires and cause a reset). I wanted to see if the problem is in servicing the watch dog but I`m unable to find which process is servicing /dev/watchdog in mfgtool linux.