Commit cc0df5eb authored by Antonio Borneo's avatar Antonio Borneo Committed by Wim Van Sebroeck
Browse files

watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT 

The optional SMCWD_GET_TIMELEFT command can be used to detect if
the watchdog has already been started.
See the implementation in OP-TEE secure OS [1].

At probe time, check if the watchdog is already started and then
set WDOG_HW_RUNNING in the watchdog status. This will cause the
watchdog framework to ping the watchdog until a userspace watchdog
daemon takes over the control.

Link: https://github.com/OP-TEE/optee_os/commit/a7f2d4bd8632

 [1]

Signed-off-by: default avatarAntonio Borneo <antonio.borneo@foss.st.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20250520085952.210723-1-antonio.borneo@foss.st.com


Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@linux-watchdog.org>
parent 27a46a0f

drivers/watchdog/arm_smc_wdt.c

+14 −3
Original line number Diff line number Diff line
@@ -46,6 +46,8 @@ static int smcwd_call(struct watchdog_device *wdd, enum smcwd_call call, 
		return -ENODEV;

	if (res->a0 == PSCI_RET_INVALID_PARAMS)

		return -EINVAL;

	if (res->a0 == PSCI_RET_DISABLED)

		return -ENODATA;

	if (res->a0 != PSCI_RET_SUCCESS)

		return -EIO;

	return 0;
@@ -131,10 +133,19 @@ static int smcwd_probe(struct platform_device *pdev) 


	wdd->info = &smcwd_info;

	/* get_timeleft is optional */

	if (smcwd_call(wdd, SMCWD_GET_TIMELEFT, 0, NULL))

		wdd->ops = &smcwd_ops;

	else

	err = smcwd_call(wdd, SMCWD_GET_TIMELEFT, 0, NULL);

	switch (err) {

	case 0:

		set_bit(WDOG_HW_RUNNING, &wdd->status);

		fallthrough;

	case -ENODATA:

		wdd->ops = &smcwd_timeleft_ops;

		break;

	default:

		wdd->ops = &smcwd_ops;

		break;

	}



	wdd->timeout = res.a2;

	wdd->max_timeout = res.a2;

	wdd->min_timeout = res.a1;