Does AM3352 watchdog supports "magic close" feature when CONFIG_WATCHDOG_NOWAYOUT is defined?

Alessandro Da Rugna

Other Parts Discussed in Thread: AM3352

I followed this guide to enable watchdog on AM3352 SoC: processors.wiki.ti.com/.../AM335x_PSP_WDT_Driver_User_Guide

I also enabled CONFIG_WATCHDOG_NOWAYOUT flag to keep the watchdog running even after closing /dev/watchdog file (see http://cateee.net/lkddb/web-lkddb/WATCHDOG_NOWAYOUT.html

over 8 years ago

0 Alessandro Da Rugna over 8 years ago

Prodigy 80 points

I cannot disable the watchdog after starting it.
The Linux Kernel documentation www.kernel.org/.../watchdog-api.txt describes the "magic close" feature: writing the character 'V' may stop the watchdog when in NOWAYOUT mode. Does AM3352 watchdog supports this feature? How do I enable it eventually?

0 Biser Gatchev-XID over 8 years ago in reply to Alessandro Da Rugna

TI__Guru**** 393215 points

Hi Alessandro,

Which Linux version are you using?

0 Alessandro Da Rugna over 8 years ago in reply to Biser Gatchev-XID

Prodigy 80 points

Hi Biser,
I am using 'linux-ti-staging-3.12' from meta-ti layer daisy branch: git.yoctoproject.org/.../meta-ti
The exact version is 3.12.30

0 Yordan Kovachev over 8 years ago in reply to Alessandro Da Rugna

TI__Guru**** 161600 points

Hi Alessandro,

The omap-wdt.c driver in TI SDK1.00.00.03 does not support checking for "magic close" character. So using nowayout once you start the watchdog, there is no way of stopping it.

Best Regards,
Yordan

0 Alessandro Da Rugna over 8 years ago in reply to Yordan Kovachev

Prodigy 80 points

Thank you very much for your reply.
Is there any TI kernel driver with "magic close" support? Or am I totally out of luck?

0 Yordan Kovachev over 8 years ago in reply to Alessandro Da Rugna

TI__Guru**** 161600 points

Hi,

I can confirm that this is not implemented in omap-wdt.c for SDKs I have:
SDK6.0 - kernel 3.2.0
SDK7.0 - kernel 3.12.10
SDK8 & SDK1.0 - kernel 3.14.26
SDK1.00.00.03 - kernel 3.14.43

Not sure about the community supported kernels (i.e. BBB community kernels).

Best Regards,
Yordan

0 STEVE HUYNH over 8 years ago in reply to Yordan Kovachev

Prodigy 180 points

Hi Yordan,

The CONFIG_WATCHDOG_NOWAYOUT in .config is NOT set but sometimes the OMAP watchdog is not stopped even after I close the file handle to /dev/watchdog. Any ideas? Your help is appreciated.

Thanks.

Hiep

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Does AM3352 watchdog supports "magic close" feature when CONFIG_WATCHDOG_NOWAYOUT is defined?