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[PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support

Started byfu.wei@linaro.org
First post2016-02-03 18:30 +0100
Last post2016-02-04 17:50 +0100
Articles 5 — 5 participants

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  [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support fu.wei@linaro.org - 2016-02-03 18:30 +0100
    Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-02-04 17:40 +0100
      Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Timur Tabi <timur@codeaurora.org> - 2016-02-04 17:50 +0100
        Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Fu Wei <fu.wei@linaro.org> - 2016-02-05 10:30 +0100
      Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout  panic support Guenter Roeck <linux@roeck-us.net> - 2016-02-04 17:50 +0100

#1325723 — [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support

Fromfu.wei@linaro.org
Date2016-02-03 18:30 +0100
Subject[PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support
Message-ID<qY9pF-4WX-15@gated-at.bofh.it>
From: Fu Wei <fu.wei@linaro.org>

This patch registers the WS0 interrupt routine to trigger panic,
when the watchdog reachs the first stage (the half timeout).
This function can help administrator to backup the system context
info by panic console output or kdump (if supported), once system
goes wrong (doesn't feed the watchdog in the half timeout).

User also can skip panic by setting panic_enabled (module parameter) as 0

Signed-off-by: Fu Wei <fu.wei@linaro.org>
---
 Documentation/watchdog/watchdog-parameters.txt |  1 +
 drivers/watchdog/Kconfig                       | 10 +++++
 drivers/watchdog/sbsa_gwdt.c                   | 54 +++++++++++++++++++++++---
 3 files changed, 60 insertions(+), 5 deletions(-)

diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt
index 300eb4d..31641e2 100644
--- a/Documentation/watchdog/watchdog-parameters.txt
+++ b/Documentation/watchdog/watchdog-parameters.txt
@@ -286,6 +286,7 @@ nowayout: Watchdog cannot be stopped once started
 -------------------------------------------------
 sbsa_gwdt:
 timeout: Watchdog timeout in seconds. (default 20s)
+panic_enabled: Enable panic at half timeout. (default=true)
 nowayout: Watchdog cannot be stopped once started
 	(default=kernel config parameter)
 -------------------------------------------------
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 4ab1b05..42adfdf 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -218,6 +218,16 @@ config ARM_SBSA_WATCHDOG
 	  To compile this driver as module, choose M here: The module
 	  will be called sbsa_gwdt.
 
+config ARM_SBSA_WATCHDOG_PANIC
+	bool "ARM SBSA Generic Watchdog triggers panic at the half timeout"
+	depends on ARM_SBSA_WATCHDOG
+	help
+	  ARM SBSA Generic Watchdog will trigger panic in the first signal
+	  (WS0) interrupt routine when the half timeout is reached.
+	  This function can help administrator to backup the system context
+	  info by panic console output or kdump (if supported).
+	  But user can skip panic by setting moduleparam panic_enabled as 0.
+
 config ASM9260_WATCHDOG
 	tristate "Alphascale ASM9260 watchdog"
 	depends on MACH_ASM9260
diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c
index 5a2dba3..d18cf37 100644
--- a/drivers/watchdog/sbsa_gwdt.c
+++ b/drivers/watchdog/sbsa_gwdt.c
@@ -16,18 +16,22 @@
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
- * This SBSA Generic watchdog driver is a single stage timeout version.
+ * This SBSA Generic watchdog driver is a two stages version.
  * Since this watchdog timer has two stages, and each stage is determined
  * by WOR. So the timeout is (WOR * 2).
- * When first timeout is reached, WS0 is triggered, the interrupt
- * triggered by WS0 will be ignored, then the second watch period starts;
- * when second timeout is reached, then WS1 is triggered, system reset.
+ * When the first stage(the half timeout) is reached, WS0 interrupt is
+ * triggered, at this moment the second watch period starts;
+ * In the WS0 interrupt routine, panic will be triggered for saving the
+ * system context.
+ * If the system is getting into trouble and cannot be reset by panic or
+ * restart properly by the kdump kernel(if supported), then the second
+ * stage (the timeout) will be reached, system will be reset by WS1.
  *
  * More details about the hardware specification of this device:
  * ARM DEN0029B - Server Base System Architecture (SBSA)
  *
  * SBSA GWDT: |--------WOR-------WS0--------WOR-------WS1
- *            |----------------timeout----------------reset
+ *            |--half_timeout--(panic)--half_timeout--reset
  *
  */
 
@@ -84,6 +88,13 @@ MODULE_PARM_DESC(timeout,
 		 "Watchdog timeout in seconds. (>=0, default="
 		 __MODULE_STRING(DEFAULT_TIMEOUT) ")");
 
+#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
+static bool panic_enabled = true;
+module_param(panic_enabled, bool, 0);
+MODULE_PARM_DESC(panic_enabled,
+		 "enable panic at half timeout. (default=true)");
+#endif
+
 static bool nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, bool, S_IRUGO);
 MODULE_PARM_DESC(nowayout,
@@ -159,6 +170,16 @@ static int sbsa_gwdt_stop(struct watchdog_device *wdd)
 	return 0;
 }
 
+#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
+static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id)
+{
+	if (panic_enabled)
+		panic("SBSA Watchdog half timeout");
+
+	return IRQ_HANDLED;
+}
+#endif
+
 static struct watchdog_info sbsa_gwdt_info = {
 	.identity	= "SBSA Generic Watchdog",
 	.options	= WDIOF_SETTIMEOUT |
@@ -186,6 +207,9 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
 	struct resource *res;
 	u32 status;
 	int ret;
+#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
+	int irq;
+#endif
 
 	gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
 	if (!gwdt)
@@ -202,6 +226,14 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
 	if (IS_ERR(rf_base))
 		return PTR_ERR(rf_base);
 
+#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dev, "unable to get ws0 interrupt.\n");
+		return irq;
+	}
+#endif
+
 	/*
 	 * Get the frequency of system counter from the cp15 interface of ARM
 	 * Generic timer. We don't need to check it, because if it returns "0",
@@ -228,6 +260,14 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
 		dev_warn(dev, "System reset by WDT.\n");
 		wdd->bootstatus |= WDIOF_CARDRESET;
 	}
+#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
+	ret = devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0,
+			       pdev->name, gwdt);
+	if (ret) {
+		dev_err(dev, "unable to request IRQ %d\n", irq);
+		return ret;
+	}
+#endif
 
 	ret = watchdog_register_device(wdd);
 	if (ret)
@@ -242,6 +282,10 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
 
 	dev_info(dev, "Initialized with %ds timeout @ %u Hz%s\n", wdd->timeout,
 		 gwdt->clk, status & SBSA_GWDT_WCS_EN ? " [enabled]" : "");
+#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
+	dev_info(dev, "Half timeout panic %s.\n",
+		 panic_enabled ? "enabled" : "disabled");
+#endif
 
 	return 0;
 }
-- 
2.5.0

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#1326978 — Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support

FromMathieu Poirier <mathieu.poirier@linaro.org>
Date2016-02-04 17:40 +0100
SubjectRe: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support
Message-ID<qYv6O-4s9-1@gated-at.bofh.it>
In reply to#1325723
On 3 February 2016 at 10:18,  <fu.wei@linaro.org> wrote:
> From: Fu Wei <fu.wei@linaro.org>
>
> This patch registers the WS0 interrupt routine to trigger panic,
> when the watchdog reachs the first stage (the half timeout).
> This function can help administrator to backup the system context
> info by panic console output or kdump (if supported), once system
> goes wrong (doesn't feed the watchdog in the half timeout).
>
> User also can skip panic by setting panic_enabled (module parameter) as 0
>
> Signed-off-by: Fu Wei <fu.wei@linaro.org>
> ---
>  Documentation/watchdog/watchdog-parameters.txt |  1 +
>  drivers/watchdog/Kconfig                       | 10 +++++
>  drivers/watchdog/sbsa_gwdt.c                   | 54 +++++++++++++++++++++++---
>  3 files changed, 60 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt
> index 300eb4d..31641e2 100644
> --- a/Documentation/watchdog/watchdog-parameters.txt
> +++ b/Documentation/watchdog/watchdog-parameters.txt
> @@ -286,6 +286,7 @@ nowayout: Watchdog cannot be stopped once started
>  -------------------------------------------------
>  sbsa_gwdt:
>  timeout: Watchdog timeout in seconds. (default 20s)
> +panic_enabled: Enable panic at half timeout. (default=true)
>  nowayout: Watchdog cannot be stopped once started
>         (default=kernel config parameter)
>  -------------------------------------------------
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 4ab1b05..42adfdf 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -218,6 +218,16 @@ config ARM_SBSA_WATCHDOG
>           To compile this driver as module, choose M here: The module
>           will be called sbsa_gwdt.
>
> +config ARM_SBSA_WATCHDOG_PANIC
> +       bool "ARM SBSA Generic Watchdog triggers panic at the half timeout"
> +       depends on ARM_SBSA_WATCHDOG
> +       help
> +         ARM SBSA Generic Watchdog will trigger panic in the first signal
> +         (WS0) interrupt routine when the half timeout is reached.
> +         This function can help administrator to backup the system context
> +         info by panic console output or kdump (if supported).
> +         But user can skip panic by setting moduleparam panic_enabled as 0.
> +
>  config ASM9260_WATCHDOG
>         tristate "Alphascale ASM9260 watchdog"
>         depends on MACH_ASM9260
> diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c
> index 5a2dba3..d18cf37 100644
> --- a/drivers/watchdog/sbsa_gwdt.c
> +++ b/drivers/watchdog/sbsa_gwdt.c
> @@ -16,18 +16,22 @@
>   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>   * GNU General Public License for more details.
>   *
> - * This SBSA Generic watchdog driver is a single stage timeout version.
> + * This SBSA Generic watchdog driver is a two stages version.
>   * Since this watchdog timer has two stages, and each stage is determined
>   * by WOR. So the timeout is (WOR * 2).
> - * When first timeout is reached, WS0 is triggered, the interrupt
> - * triggered by WS0 will be ignored, then the second watch period starts;
> - * when second timeout is reached, then WS1 is triggered, system reset.
> + * When the first stage(the half timeout) is reached, WS0 interrupt is
> + * triggered, at this moment the second watch period starts;
> + * In the WS0 interrupt routine, panic will be triggered for saving the
> + * system context.
> + * If the system is getting into trouble and cannot be reset by panic or
> + * restart properly by the kdump kernel(if supported), then the second
> + * stage (the timeout) will be reached, system will be reset by WS1.
>   *
>   * More details about the hardware specification of this device:
>   * ARM DEN0029B - Server Base System Architecture (SBSA)
>   *
>   * SBSA GWDT: |--------WOR-------WS0--------WOR-------WS1
> - *            |----------------timeout----------------reset
> + *            |--half_timeout--(panic)--half_timeout--reset
>   *
>   */
>
> @@ -84,6 +88,13 @@ MODULE_PARM_DESC(timeout,
>                  "Watchdog timeout in seconds. (>=0, default="
>                  __MODULE_STRING(DEFAULT_TIMEOUT) ")");
>
> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
> +static bool panic_enabled = true;
> +module_param(panic_enabled, bool, 0);
> +MODULE_PARM_DESC(panic_enabled,
> +                "enable panic at half timeout. (default=true)");
> +#endif
> +
>  static bool nowayout = WATCHDOG_NOWAYOUT;
>  module_param(nowayout, bool, S_IRUGO);
>  MODULE_PARM_DESC(nowayout,
> @@ -159,6 +170,16 @@ static int sbsa_gwdt_stop(struct watchdog_device *wdd)
>         return 0;
>  }
>
> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
> +static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id)
> +{
> +       if (panic_enabled)
> +               panic("SBSA Watchdog half timeout");
> +
> +       return IRQ_HANDLED;
> +}
> +#endif
> +
>  static struct watchdog_info sbsa_gwdt_info = {
>         .identity       = "SBSA Generic Watchdog",
>         .options        = WDIOF_SETTIMEOUT |
> @@ -186,6 +207,9 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>         struct resource *res;
>         u32 status;
>         int ret;
> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
> +       int irq;
> +#endif
>
>         gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
>         if (!gwdt)
> @@ -202,6 +226,14 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>         if (IS_ERR(rf_base))
>                 return PTR_ERR(rf_base);
>
> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
> +       irq = platform_get_irq(pdev, 0);
> +       if (irq < 0) {
> +               dev_err(dev, "unable to get ws0 interrupt.\n");
> +               return irq;
> +       }
> +#endif
> +

Can't the driver revert to single stage mode if platform_get_irq()
fails?  That way the value of 'irq' can be tested throughout the
_probe() function and the #ifdefs removed.

Thanks,
Mathieu

>         /*
>          * Get the frequency of system counter from the cp15 interface of ARM
>          * Generic timer. We don't need to check it, because if it returns "0",
> @@ -228,6 +260,14 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>                 dev_warn(dev, "System reset by WDT.\n");
>                 wdd->bootstatus |= WDIOF_CARDRESET;
>         }
> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
> +       ret = devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0,
> +                              pdev->name, gwdt);
> +       if (ret) {
> +               dev_err(dev, "unable to request IRQ %d\n", irq);
> +               return ret;
> +       }
> +#endif
>
>         ret = watchdog_register_device(wdd);
>         if (ret)
> @@ -242,6 +282,10 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>
>         dev_info(dev, "Initialized with %ds timeout @ %u Hz%s\n", wdd->timeout,
>                  gwdt->clk, status & SBSA_GWDT_WCS_EN ? " [enabled]" : "");
> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
> +       dev_info(dev, "Half timeout panic %s.\n",
> +                panic_enabled ? "enabled" : "disabled");
> +#endif
>
>         return 0;
>  }
> --
> 2.5.0
>

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#1326995 — Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support

FromTimur Tabi <timur@codeaurora.org>
Date2016-02-04 17:50 +0100
SubjectRe: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support
Message-ID<qYvgu-4wj-13@gated-at.bofh.it>
In reply to#1326978
Mathieu Poirier wrote:
>> >+#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
>> >+       irq = platform_get_irq(pdev, 0);
>> >+       if (irq < 0) {
>> >+               dev_err(dev, "unable to get ws0 interrupt.\n");
>> >+               return irq;
>> >+       }
>> >+#endif
>> >+
> Can't the driver revert to single stage mode if platform_get_irq()
> fails?  That way the value of 'irq' can be tested throughout the
> _probe() function and the #ifdefs removed.

I like that idea.  The same can be done with the devm_request_irq() 
call.  It should definitely still display a warning if the command-line 
option is set but no interrupt is available.

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#1327562 — Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support

FromFu Wei <fu.wei@linaro.org>
Date2016-02-05 10:30 +0100
SubjectRe: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support
Message-ID<qYKSf-6Mb-29@gated-at.bofh.it>
In reply to#1326995
On 5 February 2016 at 00:43, Timur Tabi <timur@codeaurora.org> wrote:
> Mathieu Poirier wrote:
>>>
>>> >+#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
>>> >+       irq = platform_get_irq(pdev, 0);
>>> >+       if (irq < 0) {
>>> >+               dev_err(dev, "unable to get ws0 interrupt.\n");
>>> >+               return irq;
>>> >+       }
>>> >+#endif
>>> >+
>>
>> Can't the driver revert to single stage mode if platform_get_irq()
>> fails?  That way the value of 'irq' can be tested throughout the
>> _probe() function and the #ifdefs removed.
>
>
> I like that idea.  The same can be done with the devm_request_irq() call.
> It should definitely still display a warning if the command-line option is
> set but no interrupt is available.

Yes, I agree with that too, brilliant idea, this will be in v11 patchset



-- 
Best regards,

Fu Wei
Software Engineer
Red Hat Software (Beijing) Co.,Ltd.Shanghai Branch
Ph: +86 21 61221326(direct)
Ph: +86 186 2020 4684 (mobile)
Room 1512, Regus One Corporate Avenue,Level 15,
One Corporate Avenue,222 Hubin Road,Huangpu District,
Shanghai,China 200021

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#1327004 — Re: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support

FromGuenter Roeck <linux@roeck-us.net>
Date2016-02-04 17:50 +0100
SubjectRe: [PATCH v10 5/5] Watchdog: ARM SBSA Generic Watchdog half timeout panic support
Message-ID<qYvgv-4wj-47@gated-at.bofh.it>
In reply to#1326978
On 02/04/2016 08:32 AM, Mathieu Poirier wrote:
> On 3 February 2016 at 10:18,  <fu.wei@linaro.org> wrote:
>> From: Fu Wei <fu.wei@linaro.org>
>>
>> This patch registers the WS0 interrupt routine to trigger panic,
>> when the watchdog reachs the first stage (the half timeout).
>> This function can help administrator to backup the system context
>> info by panic console output or kdump (if supported), once system
>> goes wrong (doesn't feed the watchdog in the half timeout).
>>
>> User also can skip panic by setting panic_enabled (module parameter) as 0
>>
>> Signed-off-by: Fu Wei <fu.wei@linaro.org>
>> ---
>>   Documentation/watchdog/watchdog-parameters.txt |  1 +
>>   drivers/watchdog/Kconfig                       | 10 +++++
>>   drivers/watchdog/sbsa_gwdt.c                   | 54 +++++++++++++++++++++++---
>>   3 files changed, 60 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt
>> index 300eb4d..31641e2 100644
>> --- a/Documentation/watchdog/watchdog-parameters.txt
>> +++ b/Documentation/watchdog/watchdog-parameters.txt
>> @@ -286,6 +286,7 @@ nowayout: Watchdog cannot be stopped once started
>>   -------------------------------------------------
>>   sbsa_gwdt:
>>   timeout: Watchdog timeout in seconds. (default 20s)
>> +panic_enabled: Enable panic at half timeout. (default=true)
>>   nowayout: Watchdog cannot be stopped once started
>>          (default=kernel config parameter)
>>   -------------------------------------------------
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index 4ab1b05..42adfdf 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -218,6 +218,16 @@ config ARM_SBSA_WATCHDOG
>>            To compile this driver as module, choose M here: The module
>>            will be called sbsa_gwdt.
>>
>> +config ARM_SBSA_WATCHDOG_PANIC
>> +       bool "ARM SBSA Generic Watchdog triggers panic at the half timeout"
>> +       depends on ARM_SBSA_WATCHDOG
>> +       help
>> +         ARM SBSA Generic Watchdog will trigger panic in the first signal
>> +         (WS0) interrupt routine when the half timeout is reached.
>> +         This function can help administrator to backup the system context
>> +         info by panic console output or kdump (if supported).
>> +         But user can skip panic by setting moduleparam panic_enabled as 0.
>> +
>>   config ASM9260_WATCHDOG
>>          tristate "Alphascale ASM9260 watchdog"
>>          depends on MACH_ASM9260
>> diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c
>> index 5a2dba3..d18cf37 100644
>> --- a/drivers/watchdog/sbsa_gwdt.c
>> +++ b/drivers/watchdog/sbsa_gwdt.c
>> @@ -16,18 +16,22 @@
>>    * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>    * GNU General Public License for more details.
>>    *
>> - * This SBSA Generic watchdog driver is a single stage timeout version.
>> + * This SBSA Generic watchdog driver is a two stages version.
>>    * Since this watchdog timer has two stages, and each stage is determined
>>    * by WOR. So the timeout is (WOR * 2).
>> - * When first timeout is reached, WS0 is triggered, the interrupt
>> - * triggered by WS0 will be ignored, then the second watch period starts;
>> - * when second timeout is reached, then WS1 is triggered, system reset.
>> + * When the first stage(the half timeout) is reached, WS0 interrupt is
>> + * triggered, at this moment the second watch period starts;
>> + * In the WS0 interrupt routine, panic will be triggered for saving the
>> + * system context.
>> + * If the system is getting into trouble and cannot be reset by panic or
>> + * restart properly by the kdump kernel(if supported), then the second
>> + * stage (the timeout) will be reached, system will be reset by WS1.
>>    *
>>    * More details about the hardware specification of this device:
>>    * ARM DEN0029B - Server Base System Architecture (SBSA)
>>    *
>>    * SBSA GWDT: |--------WOR-------WS0--------WOR-------WS1
>> - *            |----------------timeout----------------reset
>> + *            |--half_timeout--(panic)--half_timeout--reset
>>    *
>>    */
>>
>> @@ -84,6 +88,13 @@ MODULE_PARM_DESC(timeout,
>>                   "Watchdog timeout in seconds. (>=0, default="
>>                   __MODULE_STRING(DEFAULT_TIMEOUT) ")");
>>
>> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
>> +static bool panic_enabled = true;
>> +module_param(panic_enabled, bool, 0);
>> +MODULE_PARM_DESC(panic_enabled,
>> +                "enable panic at half timeout. (default=true)");
>> +#endif
>> +
>>   static bool nowayout = WATCHDOG_NOWAYOUT;
>>   module_param(nowayout, bool, S_IRUGO);
>>   MODULE_PARM_DESC(nowayout,
>> @@ -159,6 +170,16 @@ static int sbsa_gwdt_stop(struct watchdog_device *wdd)
>>          return 0;
>>   }
>>
>> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
>> +static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id)
>> +{
>> +       if (panic_enabled)
>> +               panic("SBSA Watchdog half timeout");
>> +
>> +       return IRQ_HANDLED;
>> +}
>> +#endif
>> +
>>   static struct watchdog_info sbsa_gwdt_info = {
>>          .identity       = "SBSA Generic Watchdog",
>>          .options        = WDIOF_SETTIMEOUT |
>> @@ -186,6 +207,9 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>>          struct resource *res;
>>          u32 status;
>>          int ret;
>> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
>> +       int irq;
>> +#endif
>>
>>          gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
>>          if (!gwdt)
>> @@ -202,6 +226,14 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>>          if (IS_ERR(rf_base))
>>                  return PTR_ERR(rf_base);
>>
>> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
>> +       irq = platform_get_irq(pdev, 0);
>> +       if (irq < 0) {
>> +               dev_err(dev, "unable to get ws0 interrupt.\n");
>> +               return irq;
>> +       }
>> +#endif
>> +
>
> Can't the driver revert to single stage mode if platform_get_irq()
> fails?  That way the value of 'irq' can be tested throughout the
> _probe() function and the #ifdefs removed.
>
Good point. Making irq support mandatory on all systems isn't really
a good idea.

Thanks,
Guenter

> Thanks,
> Mathieu
>
>>          /*
>>           * Get the frequency of system counter from the cp15 interface of ARM
>>           * Generic timer. We don't need to check it, because if it returns "0",
>> @@ -228,6 +260,14 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>>                  dev_warn(dev, "System reset by WDT.\n");
>>                  wdd->bootstatus |= WDIOF_CARDRESET;
>>          }
>> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
>> +       ret = devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0,
>> +                              pdev->name, gwdt);
>> +       if (ret) {
>> +               dev_err(dev, "unable to request IRQ %d\n", irq);
>> +               return ret;
>> +       }
>> +#endif
>>
>>          ret = watchdog_register_device(wdd);
>>          if (ret)
>> @@ -242,6 +282,10 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
>>
>>          dev_info(dev, "Initialized with %ds timeout @ %u Hz%s\n", wdd->timeout,
>>                   gwdt->clk, status & SBSA_GWDT_WCS_EN ? " [enabled]" : "");
>> +#ifdef CONFIG_ARM_SBSA_WATCHDOG_PANIC
>> +       dev_info(dev, "Half timeout panic %s.\n",
>> +                panic_enabled ? "enabled" : "disabled");
>> +#endif
>>
>>          return 0;
>>   }
>> --
>> 2.5.0
>>
>

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