[PATCH 0/2] watchdog: aspeed: Add pre-timeout interrupt support

[PATCH 0/2] watchdog: aspeed: Add pre-timeout interrupt support

[Eddie James]

Enable the pre-timeout interrupt if requested by device property, and
document that property.

Eddie James (2):
  watchdog: aspeed: Add pre-timeout interrupt support
  dt-bindings: watchdog: aspeed: Document aspeed,pre-timeout-irq-us

 .../bindings/watchdog/aspeed-wdt.txt          |  7 ++-
 drivers/watchdog/aspeed_wdt.c                 | 53 ++++++++++++++++++-
 2 files changed, 57 insertions(+), 3 deletions(-)

-- 
2.31.1

[PATCH 1/2] watchdog: aspeed: Add pre-timeout interrupt support

[Eddie James]

Enable the pre-timeout interrupt if requested by device property.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
 drivers/watchdog/aspeed_wdt.c | 53 +++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index 0cff2adfbfc9..8e12181a827e 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -5,11 +5,14 @@
  * Joel Stanley <joel@jms.id.au>
  */
 
+#include <linux/bits.h>
 #include <linux/delay.h>
+#include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>
 
@@ -26,20 +29,32 @@ struct aspeed_wdt {
 
 struct aspeed_wdt_config {
 	u32 ext_pulse_width_mask;
+	u32 irq_shift;
+	u32 irq_mask;
 };
 
 static const struct aspeed_wdt_config ast2400_config = {
 	.ext_pulse_width_mask = 0xff,
+	.irq_shift = 0,
+	.irq_mask = 0,
 };
 
 static const struct aspeed_wdt_config ast2500_config = {
 	.ext_pulse_width_mask = 0xfffff,
+	.irq_shift = 12,
+	.irq_mask = GENMASK(31, 12),
+};
+
+static const struct aspeed_wdt_config ast2600_config = {
+	.ext_pulse_width_mask = 0xfffff,
+	.irq_shift = 0,
+	.irq_mask = GENMASK(31, 10),
 };
 
 static const struct of_device_id aspeed_wdt_of_table[] = {
 	{ .compatible = "aspeed,ast2400-wdt", .data = &ast2400_config },
 	{ .compatible = "aspeed,ast2500-wdt", .data = &ast2500_config },
-	{ .compatible = "aspeed,ast2600-wdt", .data = &ast2500_config },
+	{ .compatible = "aspeed,ast2600-wdt", .data = &ast2600_config },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
@@ -58,6 +73,7 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
 #define   WDT_CTRL_RESET_SYSTEM		BIT(1)
 #define   WDT_CTRL_ENABLE		BIT(0)
 #define WDT_TIMEOUT_STATUS	0x10
+#define   WDT_TIMEOUT_STATUS_IRQ		BIT(2)
 #define   WDT_TIMEOUT_STATUS_BOOT_SECONDARY	BIT(1)
 #define WDT_CLEAR_TIMEOUT_STATUS	0x14
 #define   WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION	BIT(0)
@@ -243,6 +259,17 @@ static const struct watchdog_info aspeed_wdt_info = {
 	.identity	= KBUILD_MODNAME,
 };
 
+static irqreturn_t aspeed_wdt_irq(int irq, void *arg)
+{
+	struct aspeed_wdt *wdt = arg;
+	u32 status = readl(wdt->base + WDT_TIMEOUT_STATUS);
+
+	if (status & WDT_TIMEOUT_STATUS_IRQ)
+		panic("Watchdog pre-timeout IRQ");
+
+	return IRQ_NONE;
+}
+
 static int aspeed_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -253,6 +280,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	const char *reset_type;
 	u32 duration;
 	u32 status;
+	u32 timeout = 0;
 	int ret;
 
 	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
@@ -291,6 +319,27 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	if (of_device_is_compatible(np, "aspeed,ast2400-wdt"))
 		wdt->ctrl = WDT_CTRL_1MHZ_CLK;
 
+	if (config->irq_mask) {
+		if (!of_property_read_u32(np, "aspeed,pre-timeout-irq-us", &timeout) && timeout) {
+			int irq =  platform_get_irq(pdev, 0);
+
+			if (irq < 0) {
+				dev_warn(dev, "Couldn't find IRQ: %d\n", irq);
+				timeout = 0;
+			} else {
+				ret = devm_request_irq(dev, irq, aspeed_wdt_irq, IRQF_SHARED,
+						       dev_name(dev), wdt);
+				if (ret) {
+					dev_warn(dev, "Couldn't request IRQ:%d\n", ret);
+					timeout = 0;
+				} else {
+					wdt->ctrl |= ((timeout << config->irq_shift) &
+						      config->irq_mask) | WDT_CTRL_WDT_INTR;
+				}
+			}
+		}
+	}
+
 	/*
 	 * Control reset on a per-device basis to ensure the
 	 * host is not affected by a BMC reboot
@@ -308,7 +357,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 		else if (!strcmp(reset_type, "system"))
 			wdt->ctrl |= WDT_CTRL_RESET_MODE_FULL_CHIP |
 				     WDT_CTRL_RESET_SYSTEM;
-		else if (strcmp(reset_type, "none"))
+		else if (strcmp(reset_type, "none") && !timeout)
 			return -EINVAL;
 	}
 	if (of_property_read_bool(np, "aspeed,external-signal"))
-- 
2.31.1

[PATCH 2/2] dt-bindings: watchdog: aspeed: Document aspeed,pre-timeout-irq-us

[Eddie James]

Document this new property for the pre-timeout interrupt.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
 Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
index a8197632d6d2..81d2c35ca7e3 100644
--- a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
@@ -40,12 +40,17 @@ Optional properties:
 			specified no external signal is sent.
  - aspeed,ext-pulse-duration: External signal pulse duration in microseconds
 
-Optional properties for AST2500-compatible watchdogs:
+Optional properties for AST2500 and AST2600 compatible watchdogs:
  - aspeed,ext-push-pull: If aspeed,external-signal is present, set the pin's
 			 drive type to push-pull. The default is open-drain.
  - aspeed,ext-active-high: If aspeed,external-signal is present and and the pin
 			   is configured as push-pull, then set the pulse
 			   polarity to active-high. The default is active-low.
+ - aspeed,pre-timeout-irq-us: If aspeed,pre-timeout-irq-us is non-zero, the
+			      pre-timeout interrupt will be enabled for the
+			      watchdog. The interrupt will fire the specified
+			      number of microseconds before the watchdog expires
+			      and trigger a kernel panic.
 
 Example:
 
-- 
2.31.1

Re: [PATCH 1/2] watchdog: aspeed: Add pre-timeout interrupt support

[Guenter Roeck]

On Fri, Oct 21, 2022 at 10:15:58AM -0500, Eddie James wrote:
> Enable the pre-timeout interrupt if requested by device property.
> 

I am not inclined to accept this patch without detailed explanation.
Why would it make sense and/or be desirable to completely bypass the
watchdog core with this pretimeout support ?

Thanks,
Guenter

> Signed-off-by: Eddie James <eajames@linux.ibm.com>
> ---
>  drivers/watchdog/aspeed_wdt.c | 53 +++++++++++++++++++++++++++++++++--
>  1 file changed, 51 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
> index 0cff2adfbfc9..8e12181a827e 100644
> --- a/drivers/watchdog/aspeed_wdt.c
> +++ b/drivers/watchdog/aspeed_wdt.c
> @@ -5,11 +5,14 @@
>   * Joel Stanley <joel@jms.id.au>
>   */
>  
> +#include <linux/bits.h>
>  #include <linux/delay.h>
> +#include <linux/interrupt.h>
>  #include <linux/io.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/of_irq.h>
>  #include <linux/platform_device.h>
>  #include <linux/watchdog.h>
>  
> @@ -26,20 +29,32 @@ struct aspeed_wdt {
>  
>  struct aspeed_wdt_config {
>  	u32 ext_pulse_width_mask;
> +	u32 irq_shift;
> +	u32 irq_mask;
>  };
>  
>  static const struct aspeed_wdt_config ast2400_config = {
>  	.ext_pulse_width_mask = 0xff,
> +	.irq_shift = 0,
> +	.irq_mask = 0,
>  };
>  
>  static const struct aspeed_wdt_config ast2500_config = {
>  	.ext_pulse_width_mask = 0xfffff,
> +	.irq_shift = 12,
> +	.irq_mask = GENMASK(31, 12),
> +};
> +
> +static const struct aspeed_wdt_config ast2600_config = {
> +	.ext_pulse_width_mask = 0xfffff,
> +	.irq_shift = 0,
> +	.irq_mask = GENMASK(31, 10),
>  };
>  
>  static const struct of_device_id aspeed_wdt_of_table[] = {
>  	{ .compatible = "aspeed,ast2400-wdt", .data = &ast2400_config },
>  	{ .compatible = "aspeed,ast2500-wdt", .data = &ast2500_config },
> -	{ .compatible = "aspeed,ast2600-wdt", .data = &ast2500_config },
> +	{ .compatible = "aspeed,ast2600-wdt", .data = &ast2600_config },
>  	{ },
>  };
>  MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
> @@ -58,6 +73,7 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
>  #define   WDT_CTRL_RESET_SYSTEM		BIT(1)
>  #define   WDT_CTRL_ENABLE		BIT(0)
>  #define WDT_TIMEOUT_STATUS	0x10
> +#define   WDT_TIMEOUT_STATUS_IRQ		BIT(2)
>  #define   WDT_TIMEOUT_STATUS_BOOT_SECONDARY	BIT(1)
>  #define WDT_CLEAR_TIMEOUT_STATUS	0x14
>  #define   WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION	BIT(0)
> @@ -243,6 +259,17 @@ static const struct watchdog_info aspeed_wdt_info = {
>  	.identity	= KBUILD_MODNAME,
>  };
>  
> +static irqreturn_t aspeed_wdt_irq(int irq, void *arg)
> +{
> +	struct aspeed_wdt *wdt = arg;
> +	u32 status = readl(wdt->base + WDT_TIMEOUT_STATUS);
> +
> +	if (status & WDT_TIMEOUT_STATUS_IRQ)
> +		panic("Watchdog pre-timeout IRQ");
> +
> +	return IRQ_NONE;
> +}
> +
>  static int aspeed_wdt_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -253,6 +280,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>  	const char *reset_type;
>  	u32 duration;
>  	u32 status;
> +	u32 timeout = 0;
>  	int ret;
>  
>  	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> @@ -291,6 +319,27 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>  	if (of_device_is_compatible(np, "aspeed,ast2400-wdt"))
>  		wdt->ctrl = WDT_CTRL_1MHZ_CLK;
>  
> +	if (config->irq_mask) {
> +		if (!of_property_read_u32(np, "aspeed,pre-timeout-irq-us", &timeout) && timeout) {
> +			int irq =  platform_get_irq(pdev, 0);
> +
> +			if (irq < 0) {
> +				dev_warn(dev, "Couldn't find IRQ: %d\n", irq);
> +				timeout = 0;
> +			} else {
> +				ret = devm_request_irq(dev, irq, aspeed_wdt_irq, IRQF_SHARED,
> +						       dev_name(dev), wdt);
> +				if (ret) {
> +					dev_warn(dev, "Couldn't request IRQ:%d\n", ret);
> +					timeout = 0;
> +				} else {
> +					wdt->ctrl |= ((timeout << config->irq_shift) &
> +						      config->irq_mask) | WDT_CTRL_WDT_INTR;
> +				}
> +			}
> +		}
> +	}
> +
>  	/*
>  	 * Control reset on a per-device basis to ensure the
>  	 * host is not affected by a BMC reboot
> @@ -308,7 +357,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>  		else if (!strcmp(reset_type, "system"))
>  			wdt->ctrl |= WDT_CTRL_RESET_MODE_FULL_CHIP |
>  				     WDT_CTRL_RESET_SYSTEM;
> -		else if (strcmp(reset_type, "none"))
> +		else if (strcmp(reset_type, "none") && !timeout)
>  			return -EINVAL;
>  	}
>  	if (of_property_read_bool(np, "aspeed,external-signal"))
> -- 
> 2.31.1
> 

Re: [PATCH 1/2] watchdog: aspeed: Add pre-timeout interrupt support

[Eddie James]

On 10/21/22 11:56, Guenter Roeck wrote:
> On Fri, Oct 21, 2022 at 10:15:58AM -0500, Eddie James wrote:
>> Enable the pre-timeout interrupt if requested by device property.
>>
> I am not inclined to accept this patch without detailed explanation.
> Why would it make sense and/or be desirable to completely bypass the
> watchdog core with this pretimeout support ?


Sorry, I should add more detail.

It doesn't necessarily bypass the watchdog core. It can, if you specify 
reset-type="none". But if not, the watchdog will still fire at the 
appropriate time.

The purpose is to get a stack dump from a kernel panic rather than a 
hard reset from the watchdog. The interrupt will fire a certain number 
of microseconds (configurable by dts property) before the watchdog does. 
The interrupt handler then panics, and all the CPU stacks are dumped, so 
hopefully you can catch where another processor was stuck.


I can submit v2 with this information in the commit message and/or comments.

Thanks,

Eddie


>
> Thanks,
> Guenter
>
>> Signed-off-by: Eddie James <eajames@linux.ibm.com>
>> ---
>>   drivers/watchdog/aspeed_wdt.c | 53 +++++++++++++++++++++++++++++++++--
>>   1 file changed, 51 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
>> index 0cff2adfbfc9..8e12181a827e 100644
>> --- a/drivers/watchdog/aspeed_wdt.c
>> +++ b/drivers/watchdog/aspeed_wdt.c
>> @@ -5,11 +5,14 @@
>>    * Joel Stanley <joel@jms.id.au>
>>    */
>>   
>> +#include <linux/bits.h>
>>   #include <linux/delay.h>
>> +#include <linux/interrupt.h>
>>   #include <linux/io.h>
>>   #include <linux/kernel.h>
>>   #include <linux/module.h>
>>   #include <linux/of.h>
>> +#include <linux/of_irq.h>
>>   #include <linux/platform_device.h>
>>   #include <linux/watchdog.h>
>>   
>> @@ -26,20 +29,32 @@ struct aspeed_wdt {
>>   
>>   struct aspeed_wdt_config {
>>   	u32 ext_pulse_width_mask;
>> +	u32 irq_shift;
>> +	u32 irq_mask;
>>   };
>>   
>>   static const struct aspeed_wdt_config ast2400_config = {
>>   	.ext_pulse_width_mask = 0xff,
>> +	.irq_shift = 0,
>> +	.irq_mask = 0,
>>   };
>>   
>>   static const struct aspeed_wdt_config ast2500_config = {
>>   	.ext_pulse_width_mask = 0xfffff,
>> +	.irq_shift = 12,
>> +	.irq_mask = GENMASK(31, 12),
>> +};
>> +
>> +static const struct aspeed_wdt_config ast2600_config = {
>> +	.ext_pulse_width_mask = 0xfffff,
>> +	.irq_shift = 0,
>> +	.irq_mask = GENMASK(31, 10),
>>   };
>>   
>>   static const struct of_device_id aspeed_wdt_of_table[] = {
>>   	{ .compatible = "aspeed,ast2400-wdt", .data = &ast2400_config },
>>   	{ .compatible = "aspeed,ast2500-wdt", .data = &ast2500_config },
>> -	{ .compatible = "aspeed,ast2600-wdt", .data = &ast2500_config },
>> +	{ .compatible = "aspeed,ast2600-wdt", .data = &ast2600_config },
>>   	{ },
>>   };
>>   MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
>> @@ -58,6 +73,7 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
>>   #define   WDT_CTRL_RESET_SYSTEM		BIT(1)
>>   #define   WDT_CTRL_ENABLE		BIT(0)
>>   #define WDT_TIMEOUT_STATUS	0x10
>> +#define   WDT_TIMEOUT_STATUS_IRQ		BIT(2)
>>   #define   WDT_TIMEOUT_STATUS_BOOT_SECONDARY	BIT(1)
>>   #define WDT_CLEAR_TIMEOUT_STATUS	0x14
>>   #define   WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION	BIT(0)
>> @@ -243,6 +259,17 @@ static const struct watchdog_info aspeed_wdt_info = {
>>   	.identity	= KBUILD_MODNAME,
>>   };
>>   
>> +static irqreturn_t aspeed_wdt_irq(int irq, void *arg)
>> +{
>> +	struct aspeed_wdt *wdt = arg;
>> +	u32 status = readl(wdt->base + WDT_TIMEOUT_STATUS);
>> +
>> +	if (status & WDT_TIMEOUT_STATUS_IRQ)
>> +		panic("Watchdog pre-timeout IRQ");
>> +
>> +	return IRQ_NONE;
>> +}
>> +
>>   static int aspeed_wdt_probe(struct platform_device *pdev)
>>   {
>>   	struct device *dev = &pdev->dev;
>> @@ -253,6 +280,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>>   	const char *reset_type;
>>   	u32 duration;
>>   	u32 status;
>> +	u32 timeout = 0;
>>   	int ret;
>>   
>>   	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
>> @@ -291,6 +319,27 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>>   	if (of_device_is_compatible(np, "aspeed,ast2400-wdt"))
>>   		wdt->ctrl = WDT_CTRL_1MHZ_CLK;
>>   
>> +	if (config->irq_mask) {
>> +		if (!of_property_read_u32(np, "aspeed,pre-timeout-irq-us", &timeout) && timeout) {
>> +			int irq =  platform_get_irq(pdev, 0);
>> +
>> +			if (irq < 0) {
>> +				dev_warn(dev, "Couldn't find IRQ: %d\n", irq);
>> +				timeout = 0;
>> +			} else {
>> +				ret = devm_request_irq(dev, irq, aspeed_wdt_irq, IRQF_SHARED,
>> +						       dev_name(dev), wdt);
>> +				if (ret) {
>> +					dev_warn(dev, "Couldn't request IRQ:%d\n", ret);
>> +					timeout = 0;
>> +				} else {
>> +					wdt->ctrl |= ((timeout << config->irq_shift) &
>> +						      config->irq_mask) | WDT_CTRL_WDT_INTR;
>> +				}
>> +			}
>> +		}
>> +	}
>> +
>>   	/*
>>   	 * Control reset on a per-device basis to ensure the
>>   	 * host is not affected by a BMC reboot
>> @@ -308,7 +357,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>>   		else if (!strcmp(reset_type, "system"))
>>   			wdt->ctrl |= WDT_CTRL_RESET_MODE_FULL_CHIP |
>>   				     WDT_CTRL_RESET_SYSTEM;
>> -		else if (strcmp(reset_type, "none"))
>> +		else if (strcmp(reset_type, "none") && !timeout)
>>   			return -EINVAL;
>>   	}
>>   	if (of_property_read_bool(np, "aspeed,external-signal"))
>> -- 
>> 2.31.1
>>

Re: [PATCH 1/2] watchdog: aspeed: Add pre-timeout interrupt support

[Guenter Roeck]

On 10/21/22 12:39, Eddie James wrote:
> 
> On 10/21/22 11:56, Guenter Roeck wrote:
>> On Fri, Oct 21, 2022 at 10:15:58AM -0500, Eddie James wrote:
>>> Enable the pre-timeout interrupt if requested by device property.
>>>
>> I am not inclined to accept this patch without detailed explanation.
>> Why would it make sense and/or be desirable to completely bypass the
>> watchdog core with this pretimeout support ?
> 
> 
> Sorry, I should add more detail.
> 
> It doesn't necessarily bypass the watchdog core. It can, if you specify reset-type="none". But if not, the watchdog will still fire at the appropriate time.
> 
> The purpose is to get a stack dump from a kernel panic rather than a hard reset from the watchdog. The interrupt will fire a certain number of microseconds (configurable by dts property) before the watchdog does. The interrupt handler then panics, and all the CPU stacks are dumped, so hopefully you can catch where another processor was stuck.
> 
> 
> I can submit v2 with this information in the commit message and/or comments.
> 

You did not answer the question why you do not use the pretimeout functionality
supported by the watchdog core.

Guenter

> Thanks,
> 
> Eddie
> 
> 
>>
>> Thanks,
>> Guenter
>>
>>> Signed-off-by: Eddie James <eajames@linux.ibm.com>
>>> ---
>>>   drivers/watchdog/aspeed_wdt.c | 53 +++++++++++++++++++++++++++++++++--
>>>   1 file changed, 51 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
>>> index 0cff2adfbfc9..8e12181a827e 100644
>>> --- a/drivers/watchdog/aspeed_wdt.c
>>> +++ b/drivers/watchdog/aspeed_wdt.c
>>> @@ -5,11 +5,14 @@
>>>    * Joel Stanley <joel@jms.id.au>
>>>    */
>>> +#include <linux/bits.h>
>>>   #include <linux/delay.h>
>>> +#include <linux/interrupt.h>
>>>   #include <linux/io.h>
>>>   #include <linux/kernel.h>
>>>   #include <linux/module.h>
>>>   #include <linux/of.h>
>>> +#include <linux/of_irq.h>
>>>   #include <linux/platform_device.h>
>>>   #include <linux/watchdog.h>
>>> @@ -26,20 +29,32 @@ struct aspeed_wdt {
>>>   struct aspeed_wdt_config {
>>>       u32 ext_pulse_width_mask;
>>> +    u32 irq_shift;
>>> +    u32 irq_mask;
>>>   };
>>>   static const struct aspeed_wdt_config ast2400_config = {
>>>       .ext_pulse_width_mask = 0xff,
>>> +    .irq_shift = 0,
>>> +    .irq_mask = 0,
>>>   };
>>>   static const struct aspeed_wdt_config ast2500_config = {
>>>       .ext_pulse_width_mask = 0xfffff,
>>> +    .irq_shift = 12,
>>> +    .irq_mask = GENMASK(31, 12),
>>> +};
>>> +
>>> +static const struct aspeed_wdt_config ast2600_config = {
>>> +    .ext_pulse_width_mask = 0xfffff,
>>> +    .irq_shift = 0,
>>> +    .irq_mask = GENMASK(31, 10),
>>>   };
>>>   static const struct of_device_id aspeed_wdt_of_table[] = {
>>>       { .compatible = "aspeed,ast2400-wdt", .data = &ast2400_config },
>>>       { .compatible = "aspeed,ast2500-wdt", .data = &ast2500_config },
>>> -    { .compatible = "aspeed,ast2600-wdt", .data = &ast2500_config },
>>> +    { .compatible = "aspeed,ast2600-wdt", .data = &ast2600_config },
>>>       { },
>>>   };
>>>   MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
>>> @@ -58,6 +73,7 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
>>>   #define   WDT_CTRL_RESET_SYSTEM        BIT(1)
>>>   #define   WDT_CTRL_ENABLE        BIT(0)
>>>   #define WDT_TIMEOUT_STATUS    0x10
>>> +#define   WDT_TIMEOUT_STATUS_IRQ        BIT(2)
>>>   #define   WDT_TIMEOUT_STATUS_BOOT_SECONDARY    BIT(1)
>>>   #define WDT_CLEAR_TIMEOUT_STATUS    0x14
>>>   #define   WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION    BIT(0)
>>> @@ -243,6 +259,17 @@ static const struct watchdog_info aspeed_wdt_info = {
>>>       .identity    = KBUILD_MODNAME,
>>>   };
>>> +static irqreturn_t aspeed_wdt_irq(int irq, void *arg)
>>> +{
>>> +    struct aspeed_wdt *wdt = arg;
>>> +    u32 status = readl(wdt->base + WDT_TIMEOUT_STATUS);
>>> +
>>> +    if (status & WDT_TIMEOUT_STATUS_IRQ)
>>> +        panic("Watchdog pre-timeout IRQ");
>>> +
>>> +    return IRQ_NONE;
>>> +}
>>> +
>>>   static int aspeed_wdt_probe(struct platform_device *pdev)
>>>   {
>>>       struct device *dev = &pdev->dev;
>>> @@ -253,6 +280,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>>>       const char *reset_type;
>>>       u32 duration;
>>>       u32 status;
>>> +    u32 timeout = 0;
>>>       int ret;
>>>       wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
>>> @@ -291,6 +319,27 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>>>       if (of_device_is_compatible(np, "aspeed,ast2400-wdt"))
>>>           wdt->ctrl = WDT_CTRL_1MHZ_CLK;
>>> +    if (config->irq_mask) {
>>> +        if (!of_property_read_u32(np, "aspeed,pre-timeout-irq-us", &timeout) && timeout) {
>>> +            int irq =  platform_get_irq(pdev, 0);
>>> +
>>> +            if (irq < 0) {
>>> +                dev_warn(dev, "Couldn't find IRQ: %d\n", irq);
>>> +                timeout = 0;
>>> +            } else {
>>> +                ret = devm_request_irq(dev, irq, aspeed_wdt_irq, IRQF_SHARED,
>>> +                               dev_name(dev), wdt);
>>> +                if (ret) {
>>> +                    dev_warn(dev, "Couldn't request IRQ:%d\n", ret);
>>> +                    timeout = 0;
>>> +                } else {
>>> +                    wdt->ctrl |= ((timeout << config->irq_shift) &
>>> +                              config->irq_mask) | WDT_CTRL_WDT_INTR;
>>> +                }
>>> +            }
>>> +        }
>>> +    }
>>> +
>>>       /*
>>>        * Control reset on a per-device basis to ensure the
>>>        * host is not affected by a BMC reboot
>>> @@ -308,7 +357,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>>>           else if (!strcmp(reset_type, "system"))
>>>               wdt->ctrl |= WDT_CTRL_RESET_MODE_FULL_CHIP |
>>>                        WDT_CTRL_RESET_SYSTEM;
>>> -        else if (strcmp(reset_type, "none"))
>>> +        else if (strcmp(reset_type, "none") && !timeout)
>>>               return -EINVAL;
>>>       }
>>>       if (of_property_read_bool(np, "aspeed,external-signal"))
>>> -- 
>>> 2.31.1
>>>

Re: [PATCH 2/2] dt-bindings: watchdog: aspeed: Document aspeed,pre-timeout-irq-us

[Krzysztof Kozlowski]

On 21/10/2022 11:15, Eddie James wrote:
> Document this new property for the pre-timeout interrupt.

Please convert bindings to DT schema first.

Best regards,
Krzysztof

Re: [PATCH 2/2] dt-bindings: watchdog: aspeed: Document aspeed,pre-timeout-irq-us

[Rob Herring]

On Fri, Oct 21, 2022 at 10:15:59AM -0500, Eddie James wrote:
> Document this new property for the pre-timeout interrupt.
> 
> Signed-off-by: Eddie James <eajames@linux.ibm.com>
> ---
>  Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
> index a8197632d6d2..81d2c35ca7e3 100644
> --- a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
> +++ b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
> @@ -40,12 +40,17 @@ Optional properties:
>  			specified no external signal is sent.
>   - aspeed,ext-pulse-duration: External signal pulse duration in microseconds
>  
> -Optional properties for AST2500-compatible watchdogs:
> +Optional properties for AST2500 and AST2600 compatible watchdogs:
>   - aspeed,ext-push-pull: If aspeed,external-signal is present, set the pin's
>  			 drive type to push-pull. The default is open-drain.
>   - aspeed,ext-active-high: If aspeed,external-signal is present and and the pin
>  			   is configured as push-pull, then set the pulse
>  			   polarity to active-high. The default is active-low.
> + - aspeed,pre-timeout-irq-us: If aspeed,pre-timeout-irq-us is non-zero, the
> +			      pre-timeout interrupt will be enabled for the
> +			      watchdog. The interrupt will fire the specified
> +			      number of microseconds before the watchdog expires
> +			      and trigger a kernel panic.

A pre-timeout interrupt is fairly common. Come up with a common property 
please. You'll need to be clear if the time is from wdog restart or time 
before final timeout. 

Rob

Re: [PATCH 2/2] dt-bindings: watchdog: aspeed: Document aspeed,pre-timeout-irq-us

[Guenter Roeck]

On 10/24/22 11:44, Rob Herring wrote:
> On Fri, Oct 21, 2022 at 10:15:59AM -0500, Eddie James wrote:
>> Document this new property for the pre-timeout interrupt.
>>
>> Signed-off-by: Eddie James <eajames@linux.ibm.com>
>> ---
>>   Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt | 7 ++++++-
>>   1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
>> index a8197632d6d2..81d2c35ca7e3 100644
>> --- a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
>> +++ b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
>> @@ -40,12 +40,17 @@ Optional properties:
>>   			specified no external signal is sent.
>>    - aspeed,ext-pulse-duration: External signal pulse duration in microseconds
>>   
>> -Optional properties for AST2500-compatible watchdogs:
>> +Optional properties for AST2500 and AST2600 compatible watchdogs:
>>    - aspeed,ext-push-pull: If aspeed,external-signal is present, set the pin's
>>   			 drive type to push-pull. The default is open-drain.
>>    - aspeed,ext-active-high: If aspeed,external-signal is present and and the pin
>>   			   is configured as push-pull, then set the pulse
>>   			   polarity to active-high. The default is active-low.
>> + - aspeed,pre-timeout-irq-us: If aspeed,pre-timeout-irq-us is non-zero, the
>> +			      pre-timeout interrupt will be enabled for the
>> +			      watchdog. The interrupt will fire the specified
>> +			      number of microseconds before the watchdog expires
>> +			      and trigger a kernel panic.
> 
> A pre-timeout interrupt is fairly common. Come up with a common property
> please. You'll need to be clear if the time is from wdog restart or time
> before final timeout.
> 

It would be nice if it would match the semantics of the existing
pretimeout attribute in the watchdog core.

Guenter

Re: [PATCH 1/2] watchdog: aspeed: Add pre-timeout interrupt support

[Eddie James]

On 10/21/22 23:00, Guenter Roeck wrote:
> On 10/21/22 12:39, Eddie James wrote:
>>
>> On 10/21/22 11:56, Guenter Roeck wrote:
>>> On Fri, Oct 21, 2022 at 10:15:58AM -0500, Eddie James wrote:
>>>> Enable the pre-timeout interrupt if requested by device property.
>>>>
>>> I am not inclined to accept this patch without detailed explanation.
>>> Why would it make sense and/or be desirable to completely bypass the
>>> watchdog core with this pretimeout support ?
>>
>>
>> Sorry, I should add more detail.
>>
>> It doesn't necessarily bypass the watchdog core. It can, if you 
>> specify reset-type="none". But if not, the watchdog will still fire 
>> at the appropriate time.
>>
>> The purpose is to get a stack dump from a kernel panic rather than a 
>> hard reset from the watchdog. The interrupt will fire a certain 
>> number of microseconds (configurable by dts property) before the 
>> watchdog does. The interrupt handler then panics, and all the CPU 
>> stacks are dumped, so hopefully you can catch where another processor 
>> was stuck.
>>
>>
>> I can submit v2 with this information in the commit message and/or 
>> comments.
>>
>
> You did not answer the question why you do not use the pretimeout 
> functionality
> supported by the watchdog core.


I misunderstood your question and I wasn't actually aware of the 
pretimeout support in the core. I have sent v2 using the core pretimeout.


Thanks,

Eddie


>
> Guenter
>
>> Thanks,
>>
>> Eddie
>>
>>
>>>
>>> Thanks,
>>> Guenter
>>>
>>>> Signed-off-by: Eddie James <eajames@linux.ibm.com>
>>>> ---
>>>>   drivers/watchdog/aspeed_wdt.c | 53 
>>>> +++++++++++++++++++++++++++++++++--
>>>>   1 file changed, 51 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/watchdog/aspeed_wdt.c 
>>>> b/drivers/watchdog/aspeed_wdt.c
>>>> index 0cff2adfbfc9..8e12181a827e 100644
>>>> --- a/drivers/watchdog/aspeed_wdt.c
>>>> +++ b/drivers/watchdog/aspeed_wdt.c
>>>> @@ -5,11 +5,14 @@
>>>>    * Joel Stanley <joel@jms.id.au>
>>>>    */
>>>> +#include <linux/bits.h>
>>>>   #include <linux/delay.h>
>>>> +#include <linux/interrupt.h>
>>>>   #include <linux/io.h>
>>>>   #include <linux/kernel.h>
>>>>   #include <linux/module.h>
>>>>   #include <linux/of.h>
>>>> +#include <linux/of_irq.h>
>>>>   #include <linux/platform_device.h>
>>>>   #include <linux/watchdog.h>
>>>> @@ -26,20 +29,32 @@ struct aspeed_wdt {
>>>>   struct aspeed_wdt_config {
>>>>       u32 ext_pulse_width_mask;
>>>> +    u32 irq_shift;
>>>> +    u32 irq_mask;
>>>>   };
>>>>   static const struct aspeed_wdt_config ast2400_config = {
>>>>       .ext_pulse_width_mask = 0xff,
>>>> +    .irq_shift = 0,
>>>> +    .irq_mask = 0,
>>>>   };
>>>>   static const struct aspeed_wdt_config ast2500_config = {
>>>>       .ext_pulse_width_mask = 0xfffff,
>>>> +    .irq_shift = 12,
>>>> +    .irq_mask = GENMASK(31, 12),
>>>> +};
>>>> +
>>>> +static const struct aspeed_wdt_config ast2600_config = {
>>>> +    .ext_pulse_width_mask = 0xfffff,
>>>> +    .irq_shift = 0,
>>>> +    .irq_mask = GENMASK(31, 10),
>>>>   };
>>>>   static const struct of_device_id aspeed_wdt_of_table[] = {
>>>>       { .compatible = "aspeed,ast2400-wdt", .data = &ast2400_config },
>>>>       { .compatible = "aspeed,ast2500-wdt", .data = &ast2500_config },
>>>> -    { .compatible = "aspeed,ast2600-wdt", .data = &ast2500_config },
>>>> +    { .compatible = "aspeed,ast2600-wdt", .data = &ast2600_config },
>>>>       { },
>>>>   };
>>>>   MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
>>>> @@ -58,6 +73,7 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
>>>>   #define   WDT_CTRL_RESET_SYSTEM        BIT(1)
>>>>   #define   WDT_CTRL_ENABLE        BIT(0)
>>>>   #define WDT_TIMEOUT_STATUS    0x10
>>>> +#define   WDT_TIMEOUT_STATUS_IRQ        BIT(2)
>>>>   #define   WDT_TIMEOUT_STATUS_BOOT_SECONDARY    BIT(1)
>>>>   #define WDT_CLEAR_TIMEOUT_STATUS    0x14
>>>>   #define   WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION BIT(0)
>>>> @@ -243,6 +259,17 @@ static const struct watchdog_info 
>>>> aspeed_wdt_info = {
>>>>       .identity    = KBUILD_MODNAME,
>>>>   };
>>>> +static irqreturn_t aspeed_wdt_irq(int irq, void *arg)
>>>> +{
>>>> +    struct aspeed_wdt *wdt = arg;
>>>> +    u32 status = readl(wdt->base + WDT_TIMEOUT_STATUS);
>>>> +
>>>> +    if (status & WDT_TIMEOUT_STATUS_IRQ)
>>>> +        panic("Watchdog pre-timeout IRQ");
>>>> +
>>>> +    return IRQ_NONE;
>>>> +}
>>>> +
>>>>   static int aspeed_wdt_probe(struct platform_device *pdev)
>>>>   {
>>>>       struct device *dev = &pdev->dev;
>>>> @@ -253,6 +280,7 @@ static int aspeed_wdt_probe(struct 
>>>> platform_device *pdev)
>>>>       const char *reset_type;
>>>>       u32 duration;
>>>>       u32 status;
>>>> +    u32 timeout = 0;
>>>>       int ret;
>>>>       wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
>>>> @@ -291,6 +319,27 @@ static int aspeed_wdt_probe(struct 
>>>> platform_device *pdev)
>>>>       if (of_device_is_compatible(np, "aspeed,ast2400-wdt"))
>>>>           wdt->ctrl = WDT_CTRL_1MHZ_CLK;
>>>> +    if (config->irq_mask) {
>>>> +        if (!of_property_read_u32(np, "aspeed,pre-timeout-irq-us", 
>>>> &timeout) && timeout) {
>>>> +            int irq =  platform_get_irq(pdev, 0);
>>>> +
>>>> +            if (irq < 0) {
>>>> +                dev_warn(dev, "Couldn't find IRQ: %d\n", irq);
>>>> +                timeout = 0;
>>>> +            } else {
>>>> +                ret = devm_request_irq(dev, irq, aspeed_wdt_irq, 
>>>> IRQF_SHARED,
>>>> +                               dev_name(dev), wdt);
>>>> +                if (ret) {
>>>> +                    dev_warn(dev, "Couldn't request IRQ:%d\n", ret);
>>>> +                    timeout = 0;
>>>> +                } else {
>>>> +                    wdt->ctrl |= ((timeout << config->irq_shift) &
>>>> +                              config->irq_mask) | WDT_CTRL_WDT_INTR;
>>>> +                }
>>>> +            }
>>>> +        }
>>>> +    }
>>>> +
>>>>       /*
>>>>        * Control reset on a per-device basis to ensure the
>>>>        * host is not affected by a BMC reboot
>>>> @@ -308,7 +357,7 @@ static int aspeed_wdt_probe(struct 
>>>> platform_device *pdev)
>>>>           else if (!strcmp(reset_type, "system"))
>>>>               wdt->ctrl |= WDT_CTRL_RESET_MODE_FULL_CHIP |
>>>>                        WDT_CTRL_RESET_SYSTEM;
>>>> -        else if (strcmp(reset_type, "none"))
>>>> +        else if (strcmp(reset_type, "none") && !timeout)
>>>>               return -EINVAL;
>>>>       }
>>>>       if (of_property_read_bool(np, "aspeed,external-signal"))
>>>> -- 
>>>> 2.31.1
>>>>
>