* [PATCH] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT
@ 2025-05-19 17:00 Antonio Borneo
2025-05-19 17:58 ` Guenter Roeck
2025-05-20 8:59 ` [PATCH v2] " Antonio Borneo
0 siblings, 2 replies; 7+ messages in thread
From: Antonio Borneo @ 2025-05-19 17:00 UTC (permalink / raw)
To: Julius Werner, Evan Benn, Wim Van Sebroeck, Guenter Roeck,
linux-watchdog, linux-kernel
Cc: Antonio Borneo, linux-stm32
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].
If CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set, 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 | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c
index 8f3d0c3a005fb..f1268f43327ea 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 +133,20 @@ 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:
+ if (IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED))
+ 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
--
2.34.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT
2025-05-19 17:00 [PATCH] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT Antonio Borneo
@ 2025-05-19 17:58 ` Guenter Roeck
2025-05-20 0:12 ` Julius Werner
2025-05-20 8:59 ` [PATCH v2] " Antonio Borneo
1 sibling, 1 reply; 7+ messages in thread
From: Guenter Roeck @ 2025-05-19 17:58 UTC (permalink / raw)
To: Antonio Borneo, Julius Werner, Evan Benn, Wim Van Sebroeck,
linux-watchdog, linux-kernel
Cc: linux-stm32
On 5/19/25 10:00, 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].
>
> If CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set, 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 | 18 +++++++++++++++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c
> index 8f3d0c3a005fb..f1268f43327ea 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 +133,20 @@ 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:
> + if (IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED))
> + set_bit(WDOG_HW_RUNNING, &wdd->status);
This is the wrong use of this configuration option. It is only needed
in a driver if the watchdog status can not be read from hardware.
That is not the case here. Worse, using it in a driver like this
overrides the watchdog core module parameter "handle_boot_enabled".
Guenter
> + 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
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT
2025-05-19 17:58 ` Guenter Roeck
@ 2025-05-20 0:12 ` Julius Werner
2025-05-20 1:13 ` Guenter Roeck
0 siblings, 1 reply; 7+ messages in thread
From: Julius Werner @ 2025-05-20 0:12 UTC (permalink / raw)
To: Guenter Roeck
Cc: Antonio Borneo, Julius Werner, Evan Benn, Wim Van Sebroeck,
linux-watchdog, linux-kernel, linux-stm32
I don't really know about the issue Guenter mentioned, but otherwise,
from the driver's side this looks good to me.
Reviewed-by: Julius Werner <jwerner@chromium.org>
On Mon, May 19, 2025 at 10:58 AM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On 5/19/25 10:00, 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].
> >
> > If CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set, 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 | 18 +++++++++++++++---
> > 1 file changed, 15 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c
> > index 8f3d0c3a005fb..f1268f43327ea 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 +133,20 @@ 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:
> > + if (IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED))
> > + set_bit(WDOG_HW_RUNNING, &wdd->status);
>
> This is the wrong use of this configuration option. It is only needed
> in a driver if the watchdog status can not be read from hardware.
> That is not the case here. Worse, using it in a driver like this
> overrides the watchdog core module parameter "handle_boot_enabled".
>
> Guenter
>
> > + 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
>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT
2025-05-20 0:12 ` Julius Werner
@ 2025-05-20 1:13 ` Guenter Roeck
2025-05-20 8:49 ` Antonio Borneo
0 siblings, 1 reply; 7+ messages in thread
From: Guenter Roeck @ 2025-05-20 1:13 UTC (permalink / raw)
To: Julius Werner
Cc: Antonio Borneo, Evan Benn, Wim Van Sebroeck, linux-watchdog,
linux-kernel, linux-stm32
On 5/19/25 17:12, Julius Werner wrote:
> I don't really know about the issue Guenter mentioned, but otherwise,
> from the driver's side this looks good to me.
>
It should just be
set_bit(WDOG_HW_RUNNING, &wdd->status);
There should be no dependency on CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED.
Guenter
> Reviewed-by: Julius Werner <jwerner@chromium.org>
>
> On Mon, May 19, 2025 at 10:58 AM Guenter Roeck <linux@roeck-us.net> wrote:
>>
>> On 5/19/25 10:00, 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].
>>>
>>> If CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set, 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 | 18 +++++++++++++++---
>>> 1 file changed, 15 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c
>>> index 8f3d0c3a005fb..f1268f43327ea 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 +133,20 @@ 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:
>>> + if (IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED))
>>> + set_bit(WDOG_HW_RUNNING, &wdd->status);
>>
>> This is the wrong use of this configuration option. It is only needed
>> in a driver if the watchdog status can not be read from hardware.
>> That is not the case here. Worse, using it in a driver like this
>> overrides the watchdog core module parameter "handle_boot_enabled".
>>
>> Guenter
>>
>>> + 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
>>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT
2025-05-20 1:13 ` Guenter Roeck
@ 2025-05-20 8:49 ` Antonio Borneo
0 siblings, 0 replies; 7+ messages in thread
From: Antonio Borneo @ 2025-05-20 8:49 UTC (permalink / raw)
To: Guenter Roeck, Julius Werner
Cc: Evan Benn, Wim Van Sebroeck, linux-watchdog, linux-kernel,
linux-stm32
On Mon, 2025-05-19 at 18:13 -0700, Guenter Roeck wrote:
> On 5/19/25 17:12, Julius Werner wrote:
> > I don't really know about the issue Guenter mentioned, but otherwise,
> > from the driver's side this looks good to me.
> >
>
> It should just be
> set_bit(WDOG_HW_RUNNING, &wdd->status);
>
> There should be no dependency on CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED.
>
> Guenter
>
Thanks for the review!
I agree on Guenter's comment and I will send a V2 shortly.
Regards
Antonio
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT
2025-05-19 17:00 [PATCH] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT Antonio Borneo
2025-05-19 17:58 ` Guenter Roeck
@ 2025-05-20 8:59 ` Antonio Borneo
2025-05-20 18:48 ` Guenter Roeck
1 sibling, 1 reply; 7+ messages in thread
From: Antonio Borneo @ 2025-05-20 8:59 UTC (permalink / raw)
To: Julius Werner, Evan Benn, Wim Van Sebroeck, Guenter Roeck,
linux-watchdog, linux-kernel
Cc: Antonio Borneo, linux-stm32
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(-)
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
--
2.34.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH v2] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT
2025-05-20 8:59 ` [PATCH v2] " Antonio Borneo
@ 2025-05-20 18:48 ` Guenter Roeck
0 siblings, 0 replies; 7+ messages in thread
From: Guenter Roeck @ 2025-05-20 18:48 UTC (permalink / raw)
To: Antonio Borneo, Julius Werner, Evan Benn, Wim Van Sebroeck,
linux-watchdog, linux-kernel
Cc: linux-stm32
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
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2025-05-20 18:48 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
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2025-05-19 17:00 [PATCH] watchdog: arm_smc_wdt: get wdt status through SMCWD_GET_TIMELEFT Antonio Borneo
2025-05-19 17:58 ` Guenter Roeck
2025-05-20 0:12 ` Julius Werner
2025-05-20 1:13 ` Guenter Roeck
2025-05-20 8:49 ` Antonio Borneo
2025-05-20 8:59 ` [PATCH v2] " Antonio Borneo
2025-05-20 18:48 ` Guenter Roeck
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