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* driver: watchdog: Remove mtk_wdt_stop() in probe() to prevent the system freeze and it doesn't reboot by watchdog problem
@ 2020-12-25  7:30 Freddy Hsin
  2020-12-25  7:30 ` [PATCH v1 1/1] " Freddy Hsin
  2020-12-25 14:27 ` Guenter Roeck
  0 siblings, 2 replies; 6+ messages in thread
From: Freddy Hsin @ 2020-12-25  7:30 UTC (permalink / raw)
  To: Freddy Hsin, Wim Van Sebroeck, Guenter Roeck, Matthias Brugger,
	linux-watchdog, linux-arm-kernel, linux-mediatek, linux-kernel
  Cc: wsd_upstream, chang-an.chen, kuohong.wang

Before user space daemon start to access the watchdog device,
there is a time interval that watchdog is disabled in the
original flow. If the system freezing at this interval, it
cannot be rebooted by watchdog hardware automatically.

In order to solve this problem, the watchdog hardware should be
kept working, and start hrtimer in framework to ping it by
setting max_hw_heartbeat_ms and HW_RUNNING used in
watchdog_need_worker to determine whether the worker should be
started or not


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH v1 1/1] driver: watchdog: Remove mtk_wdt_stop() in probe() to prevent the system freeze and it doesn't reboot by watchdog problem
  2020-12-25  7:30 driver: watchdog: Remove mtk_wdt_stop() in probe() to prevent the system freeze and it doesn't reboot by watchdog problem Freddy Hsin
@ 2020-12-25  7:30 ` Freddy Hsin
  2020-12-25 14:27   ` Guenter Roeck
  2020-12-25 14:29   ` Guenter Roeck
  2020-12-25 14:27 ` Guenter Roeck
  1 sibling, 2 replies; 6+ messages in thread
From: Freddy Hsin @ 2020-12-25  7:30 UTC (permalink / raw)
  To: Freddy Hsin, Wim Van Sebroeck, Guenter Roeck, Matthias Brugger,
	linux-watchdog, linux-arm-kernel, linux-mediatek, linux-kernel
  Cc: wsd_upstream, chang-an.chen, kuohong.wang

From: "freddy.hsin" <freddy.hsin@mediatek.com>

Before user space daemon start to access the watchdog device,
there is a time interval that watchdog is disabled in the
original flow. If the system freezing at this interval, it
cannot be rebooted by watchdog hardware automatically.

In order to solve this problem, the watchdog hardware should be
kept working, and start hrtimer in framework to ping it by
setting max_hw_heartbeat_ms and HW_RUNNING used in
watchdog_need_worker to determine whether the worker should be
started or not

Change-Id: I6a041b0922888a90011d7538ee804d80bc8d15ea
Signed-off-by: freddy.hsin <freddy.hsin@mediatek.com>
---
 drivers/watchdog/mtk_wdt.c |   22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
index d6a6393..62f08cd 100644
--- a/drivers/watchdog/mtk_wdt.c
+++ b/drivers/watchdog/mtk_wdt.c
@@ -195,6 +195,19 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
 	return 0;
 }
 
+static void mtk_wdt_init(struct watchdog_device *wdt_dev)
+{
+	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
+	void __iomem *wdt_base;
+
+	wdt_base = mtk_wdt->wdt_base;
+
+	if (readl(wdt_base + WDT_MODE) & WDT_MODE_EN) {
+		set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
+		mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
+	}
+}
+
 static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
 {
 	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
@@ -266,16 +279,17 @@ static int mtk_wdt_probe(struct platform_device *pdev)
 	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
 	mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
 	mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
+	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = (WDT_MAX_TIMEOUT - 1) * 1000;
 	mtk_wdt->wdt_dev.parent = dev;
 
+	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
+
+	mtk_wdt_init(&mtk_wdt->wdt_dev);
+
 	watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, dev);
 	watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
 	watchdog_set_restart_priority(&mtk_wdt->wdt_dev, 128);
 
-	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
-
-	mtk_wdt_stop(&mtk_wdt->wdt_dev);
-
 	watchdog_stop_on_reboot(&mtk_wdt->wdt_dev);
 	err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev);
 	if (unlikely(err))
-- 
1.7.9.5


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v1 1/1] driver: watchdog: Remove mtk_wdt_stop() in probe() to prevent the system freeze and it doesn't reboot by watchdog problem
  2020-12-25  7:30 ` [PATCH v1 1/1] " Freddy Hsin
@ 2020-12-25 14:27   ` Guenter Roeck
       [not found]     ` <1609231194.9252.6.camel@mtkswgap22>
  2020-12-25 14:29   ` Guenter Roeck
  1 sibling, 1 reply; 6+ messages in thread
From: Guenter Roeck @ 2020-12-25 14:27 UTC (permalink / raw)
  To: Freddy Hsin, Wim Van Sebroeck, Matthias Brugger, linux-watchdog,
	linux-arm-kernel, linux-mediatek, linux-kernel
  Cc: wsd_upstream, chang-an.chen, kuohong.wang

On 12/24/20 11:30 PM, Freddy Hsin wrote:
> From: "freddy.hsin" <freddy.hsin@mediatek.com>
> 
> Before user space daemon start to access the watchdog device,
> there is a time interval that watchdog is disabled in the
> original flow. If the system freezing at this interval, it
> cannot be rebooted by watchdog hardware automatically.
> 
> In order to solve this problem, the watchdog hardware should be
> kept working, and start hrtimer in framework to ping it by
> setting max_hw_heartbeat_ms and HW_RUNNING used in
> watchdog_need_worker to determine whether the worker should be
> started or not
> 
> Change-Id: I6a041b0922888a90011d7538ee804d80bc8d15ea
> Signed-off-by: freddy.hsin <freddy.hsin@mediatek.com>
> ---
>  drivers/watchdog/mtk_wdt.c |   22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> index d6a6393..62f08cd 100644
> --- a/drivers/watchdog/mtk_wdt.c
> +++ b/drivers/watchdog/mtk_wdt.c
> @@ -195,6 +195,19 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
>  	return 0;
>  }
>  
> +static void mtk_wdt_init(struct watchdog_device *wdt_dev)
> +{
> +	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
> +	void __iomem *wdt_base;
> +
> +	wdt_base = mtk_wdt->wdt_base;
> +
> +	if (readl(wdt_base + WDT_MODE) & WDT_MODE_EN) {
> +		set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
> +		mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
> +	}
> +}
> +
>  static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
>  {
>  	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
> @@ -266,16 +279,17 @@ static int mtk_wdt_probe(struct platform_device *pdev)
>  	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
>  	mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;

No longer needed if max_hw_heartbeat_ms is set.

>  	mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
> +	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = (WDT_MAX_TIMEOUT - 1) * 1000;

This needs explanation. Why WDT_MAX_TIMEOUT - 1 ?

>  	mtk_wdt->wdt_dev.parent = dev;
>  
> +	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
> +
> +	mtk_wdt_init(&mtk_wdt->wdt_dev);
> +

Setting the chip (with the maximum timeout) ...

>  	watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, dev);

just before initializing/setting the real timeout doesn't really make sense.

>  	watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
>  	watchdog_set_restart_priority(&mtk_wdt->wdt_dev, 128);
>  
> -	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
> -
> -	mtk_wdt_stop(&mtk_wdt->wdt_dev);
> -
>  	watchdog_stop_on_reboot(&mtk_wdt->wdt_dev);
>  	err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev);
>  	if (unlikely(err))
> 


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: driver: watchdog: Remove mtk_wdt_stop() in probe() to prevent the system freeze and it doesn't reboot by watchdog problem
  2020-12-25  7:30 driver: watchdog: Remove mtk_wdt_stop() in probe() to prevent the system freeze and it doesn't reboot by watchdog problem Freddy Hsin
  2020-12-25  7:30 ` [PATCH v1 1/1] " Freddy Hsin
@ 2020-12-25 14:27 ` Guenter Roeck
  1 sibling, 0 replies; 6+ messages in thread
From: Guenter Roeck @ 2020-12-25 14:27 UTC (permalink / raw)
  To: Freddy Hsin, Wim Van Sebroeck, Matthias Brugger, linux-watchdog,
	linux-arm-kernel, linux-mediatek, linux-kernel
  Cc: wsd_upstream, chang-an.chen, kuohong.wang

On 12/24/20 11:30 PM, Freddy Hsin wrote:
> Before user space daemon start to access the watchdog device,
> there is a time interval that watchdog is disabled in the
> original flow. If the system freezing at this interval, it
> cannot be rebooted by watchdog hardware automatically.
> 
> In order to solve this problem, the watchdog hardware should be
> kept working, and start hrtimer in framework to ping it by
> setting max_hw_heartbeat_ms and HW_RUNNING used in
> watchdog_need_worker to determine whether the worker should be
> started or not
> 
This intro email is unnecessary.

Guenter

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v1 1/1] driver: watchdog: Remove mtk_wdt_stop() in probe() to prevent the system freeze and it doesn't reboot by watchdog problem
  2020-12-25  7:30 ` [PATCH v1 1/1] " Freddy Hsin
  2020-12-25 14:27   ` Guenter Roeck
@ 2020-12-25 14:29   ` Guenter Roeck
  1 sibling, 0 replies; 6+ messages in thread
From: Guenter Roeck @ 2020-12-25 14:29 UTC (permalink / raw)
  To: Freddy Hsin, Wim Van Sebroeck, Matthias Brugger, linux-watchdog,
	linux-arm-kernel, linux-mediatek, linux-kernel
  Cc: wsd_upstream, chang-an.chen, kuohong.wang

On 12/24/20 11:30 PM, Freddy Hsin wrote:
> From: "freddy.hsin" <freddy.hsin@mediatek.com>
> 
> Before user space daemon start to access the watchdog device,
> there is a time interval that watchdog is disabled in the
> original flow. If the system freezing at this interval, it
> cannot be rebooted by watchdog hardware automatically.
> 
> In order to solve this problem, the watchdog hardware should be
> kept working, and start hrtimer in framework to ping it by
> setting max_hw_heartbeat_ms and HW_RUNNING used in
> watchdog_need_worker to determine whether the worker should be
> started or not
> 
> Change-Id: I6a041b0922888a90011d7538ee804d80bc8d15ea
> Signed-off-by: freddy.hsin <freddy.hsin@mediatek.com>

Also: $subject should refer to mtk_wdt.

watchdog: mtk_wdt: Do not stop watchdog in probe function

or similar.

Thanks,
Guenter

> ---
>  drivers/watchdog/mtk_wdt.c |   22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> index d6a6393..62f08cd 100644
> --- a/drivers/watchdog/mtk_wdt.c
> +++ b/drivers/watchdog/mtk_wdt.c
> @@ -195,6 +195,19 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
>  	return 0;
>  }
>  
> +static void mtk_wdt_init(struct watchdog_device *wdt_dev)
> +{
> +	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
> +	void __iomem *wdt_base;
> +
> +	wdt_base = mtk_wdt->wdt_base;
> +
> +	if (readl(wdt_base + WDT_MODE) & WDT_MODE_EN) {
> +		set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
> +		mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
> +	}
> +}
> +
>  static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
>  {
>  	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
> @@ -266,16 +279,17 @@ static int mtk_wdt_probe(struct platform_device *pdev)
>  	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
>  	mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
>  	mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
> +	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = (WDT_MAX_TIMEOUT - 1) * 1000;
>  	mtk_wdt->wdt_dev.parent = dev;
>  
> +	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
> +
> +	mtk_wdt_init(&mtk_wdt->wdt_dev);
> +
>  	watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, dev);
>  	watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
>  	watchdog_set_restart_priority(&mtk_wdt->wdt_dev, 128);
>  
> -	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
> -
> -	mtk_wdt_stop(&mtk_wdt->wdt_dev);
> -
>  	watchdog_stop_on_reboot(&mtk_wdt->wdt_dev);
>  	err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev);
>  	if (unlikely(err))
> 


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v1 1/1] driver: watchdog: Remove mtk_wdt_stop() in probe() to prevent the system freeze and it doesn't reboot by watchdog problem
       [not found]     ` <1609231194.9252.6.camel@mtkswgap22>
@ 2020-12-29 15:08       ` Guenter Roeck
  0 siblings, 0 replies; 6+ messages in thread
From: Guenter Roeck @ 2020-12-29 15:08 UTC (permalink / raw)
  To: Freddy.Hsin
  Cc: Wim Van Sebroeck, Matthias Brugger, linux-watchdog,
	linux-arm-kernel, linux-mediatek, linux-kernel, wsd_upstream,
	Chang-An Chen (陳昶安),
	Kuohong Wang (王國鴻)

On 12/29/20 12:39 AM, Freddy.Hsin wrote:
> On Fri, 2020-12-25 at 22:27 +0800, Guenter Roeck wrote:
>> On 12/24/20 11:30 PM, Freddy Hsin wrote:
>>> From: "freddy.hsin" <freddy.hsin@mediatek.com>
>>>
>>> Before user space daemon start to access the watchdog device,
>>> there is a time interval that watchdog is disabled in the
>>> original flow. If the system freezing at this interval, it
>>> cannot be rebooted by watchdog hardware automatically.
>>>
>>> In order to solve this problem, the watchdog hardware should be
>>> kept working, and start hrtimer in framework to ping it by
>>> setting max_hw_heartbeat_ms and HW_RUNNING used in
>>> watchdog_need_worker to determine whether the worker should be
>>> started or not
>>>
>>> Change-Id: I6a041b0922888a90011d7538ee804d80bc8d15ea
>>> Signed-off-by: freddy.hsin <freddy.hsin@mediatek.com>
>>> ---
>>>  drivers/watchdog/mtk_wdt.c |   22 ++++++++++++++++++----
>>>  1 file changed, 18 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
>>> index d6a6393..62f08cd 100644
>>> --- a/drivers/watchdog/mtk_wdt.c
>>> +++ b/drivers/watchdog/mtk_wdt.c
>>> @@ -195,6 +195,19 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
>>>  	return 0;
>>>  }
>>>  
>>> +static void mtk_wdt_init(struct watchdog_device *wdt_dev)
>>> +{
>>> +	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
>>> +	void __iomem *wdt_base;
>>> +
>>> +	wdt_base = mtk_wdt->wdt_base;
>>> +
>>> +	if (readl(wdt_base + WDT_MODE) & WDT_MODE_EN) {
>>> +		set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
>>> +		mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
>>> +	}
>>> +}
>>> +
>>>  static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
>>>  {
>>>  	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
>>> @@ -266,16 +279,17 @@ static int mtk_wdt_probe(struct platform_device *pdev)
>>>  	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
>>>  	mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
>>
>> No longer needed if max_hw_heartbeat_ms is set.
> 
> Got it. it will be removed in V2 patch
> 
>>
>>>  	mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
>>> +	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = (WDT_MAX_TIMEOUT - 1) * 1000;
>>
>> This needs explanation. Why WDT_MAX_TIMEOUT - 1 ?
> 
> In watchdog_need_worker(), there is a condition for starting worker (hm
> && watchdog_active(wdd) && t > hm), so I think in the case
> that watchdog_active is true, the t (timeout) should be greater than
> hm (max_hw_heartbeat_ms) or the worker will not work. Shouldn't I
> consider for this case?
> 

You are claiming that the watchdog core is buggy. Make your case there, not here.

Guenter

>>
>>>  	mtk_wdt->wdt_dev.parent = dev;
>>>  
>>> +	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
>>> +
>>> +	mtk_wdt_init(&mtk_wdt->wdt_dev);
>>> +
>>
>> Setting the chip (with the maximum timeout) ...
>>
> Got it. mtk_wdt_init will be moved after watchdog_init_timeout in V2
> 
> BRs,
> FreddyHsin
> 
>>>  	watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, dev);
>>
>> just before initializing/setting the real timeout doesn't really make sense.
>>
>>>  	watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
>>>  	watchdog_set_restart_priority(&mtk_wdt->wdt_dev, 128);
>>>  
>>> -	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
>>> -
>>> -	mtk_wdt_stop(&mtk_wdt->wdt_dev);
>>> -
>>>  	watchdog_stop_on_reboot(&mtk_wdt->wdt_dev);
>>>  	err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev);
>>>  	if (unlikely(err))
>>>
>>
> 


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, back to index

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-25  7:30 driver: watchdog: Remove mtk_wdt_stop() in probe() to prevent the system freeze and it doesn't reboot by watchdog problem Freddy Hsin
2020-12-25  7:30 ` [PATCH v1 1/1] " Freddy Hsin
2020-12-25 14:27   ` Guenter Roeck
     [not found]     ` <1609231194.9252.6.camel@mtkswgap22>
2020-12-29 15:08       ` Guenter Roeck
2020-12-25 14:29   ` Guenter Roeck
2020-12-25 14:27 ` Guenter Roeck

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