| Message ID | 20250520085952.210723-1-antonio.borneo@foss.st.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT | expand |
On 5/20/25 01:59, Antonio Borneo wrote: > 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: Antonio Borneo <antonio.borneo@foss.st.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > drivers/watchdog/arm_smc_wdt.c | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) > > diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c > index 8f3d0c3a005fb..bbba23ace7b85 100644 > --- a/drivers/watchdog/arm_smc_wdt.c > +++ b/drivers/watchdog/arm_smc_wdt.c > @@ -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; > > base-commit: a5806cd506af5a7c19bcd596e4708b5c464bfd21
diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c index 8f3d0c3a005fb..bbba23ace7b85 100644 --- a/drivers/watchdog/arm_smc_wdt.c +++ b/drivers/watchdog/arm_smc_wdt.c @@ -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;
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: Antonio Borneo <antonio.borneo@foss.st.com> --- drivers/watchdog/arm_smc_wdt.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) base-commit: a5806cd506af5a7c19bcd596e4708b5c464bfd21