watchdog: aspeed: Add pre-timeout interrupt support

PATCH Superseded Eddie James 4 participants 10 messages Oct 21, 2022 – Nov 1, 2022

Subsystems (3)

Device tree bindings Watchdog device drivers Arm/Aspeed machine support

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Eddie James

author

2022-10-21 15:15 UTC #0 lore raw

cover watchdog: aspeed: Add pre-timeout interrupt support

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(-)

Signature · 1 line

2.31.1

Eddie James

author

2022-10-21 15:15 UTC #1 lore raw

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

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

Signed-off-by Eddie James <[email protected]>

---
 drivers/watchdog/aspeed_wdt.c | 53 +++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +51 -2

index 0cff2adfbfc9..8e12181a827e 100644
@@ -5,11 +5,14 @@
  * Joel Stanley <[email protected]>
  */
 
+#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"))

Signature · 1 line

2.31.1

Eddie James

author

2022-10-21 15:15 UTC #6 lore raw

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

In reply to Eddie James

Document this new property for the pre-timeout interrupt.

Signed-off-by Eddie James <[email protected]>

---
 Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +6 -1

index a8197632d6d2..81d2c35ca7e3 100644
@@ -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:

Signature · 1 line

2.31.1

Guenter Roeck

maintainer

2022-10-21 16:56 UTC #2 lore raw

In reply to Eddie James

Quoted 2 lines · Eddie James

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

Quoted 132 lines

Signed-off-by Eddie James <[email protected]>

---
 drivers/watchdog/aspeed_wdt.c | 53 +++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +51 -2

index 0cff2adfbfc9..8e12181a827e 100644
@@ -5,11 +5,14 @@
  * Joel Stanley <[email protected]>
  */
 
+#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"))

Signature · 1 line

2.31.1

Eddie James

author

2022-10-21 19:39 UTC #3 lore raw

Quoted 6 lines · Guenter Roeck

Quoted 2 lines · Eddie James
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

Quoted 136 lines

Thanks,
Guenter

Quoted 132 lines

Signed-off-by Eddie James <[email protected]>

---
  drivers/watchdog/aspeed_wdt.c | 53 +++++++++++++++++++++++++++++++++--
  1 file changed, 51 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +51 -2

index 0cff2adfbfc9..8e12181a827e 100644
@@ -5,11 +5,14 @@
   * Joel Stanley <[email protected]>
   */
 
+#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"))

Signature · 1 line

2.31.1

Guenter Roeck

maintainer

2022-10-22 04:00 UTC #4 lore raw

Quoted 10 lines · Eddie James

Quoted 6 lines · Guenter Roeck
Quoted 2 lines · Eddie James
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 ?

Quoted 9 lines

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

Quoted 132 lines

Thanks,

Eddie

Quoted 127 lines

Thanks,
Guenter

Quoted 123 lines

Signed-off-by Eddie James <[email protected]>

---
? drivers/watchdog/aspeed_wdt.c | 53 +++++++++++++++++++++++++++++++++-- ? 1 file changed, 51 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +0 -0

index 0cff2adfbfc9..8e12181a827e 100644
@@ -5,11 +5,14 @@

?? * Joel Stanley <[email protected]>
?? */
+#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>

drivers/watchdog/aspeed_wdt.c +13 -1

@@ -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)

drivers/watchdog/aspeed_wdt.c +33 -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

drivers/watchdog/aspeed_wdt.c +0 -0

@@ -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"))

Signature · 1 line

2.31.1

Krzysztof Kozlowski

2022-10-22 16:20 UTC #7 lore raw

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

In reply to Eddie James

Quoted 1 line · Eddie James

Document this new property for the pre-timeout interrupt.

Please convert bindings to DT schema first.

Best regards,
Krzysztof

Rob Herring

maintainer

2022-10-24 18:44 UTC #8 lore raw

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

In reply to Eddie James

Quoted 17 lines · Eddie James

Document this new property for the pre-timeout interrupt.

Signed-off-by Eddie James <[email protected]>

---
 Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +1 -1

index a8197632d6d2..81d2c35ca7e3 100644
@@ -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:

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt Optional properties: · line 53

Quoted 10 lines

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +5 -0

  - 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

Guenter Roeck

maintainer

2022-10-24 19:03 UTC #9 lore raw

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

Quoted 16 lines · Rob Herring

Quoted 15 lines · Eddie James
Document this new property for the pre-timeout interrupt.
Signed-off-by Eddie James <[email protected]>
---
  Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt | 7 ++++++-
  1 file changed, 6 insertions(+), 1 deletion(-)
Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +0 -0
index a8197632d6d2..81d2c35ca7e3 100644
@@ -40,12 +40,17 @@ Optional properties:
  			specified no external signal is sent.
   - aspeed,ext-pulse-duration: External signal pulse duration in microseconds
 

Quoted 17 lines

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt Optional properties: · line 53

Quoted 12 lines

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +6 -1

-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

Eddie James

author

2022-11-01 20:54 UTC #5 lore raw

In reply to Guenter Roeck

Quoted 25 lines · Guenter Roeck

Quoted 24 lines · Eddie James
Quoted 6 lines · Guenter Roeck
Quoted 2 lines · Eddie James
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.

Quoted 7 lines

Quoted 3 lines
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

Quoted 144 lines

Guenter

Quoted 140 lines

Thanks,

Eddie

Quoted 135 lines

Thanks,
Guenter

Quoted 131 lines

Signed-off-by Eddie James <[email protected]>

---
? drivers/watchdog/aspeed_wdt.c | 53
+++++++++++++++++++++++++++++++++--
? 1 file changed, 51 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +0 -0

index 0cff2adfbfc9..8e12181a827e 100644
@@ -5,11 +5,14 @@

drivers/watchdog/aspeed_wdt.c +13 -1

@@ -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)

drivers/watchdog/aspeed_wdt.c +33 -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

drivers/watchdog/aspeed_wdt.c +0 -0

@@ -308,7 +357,7 @@ static int aspeed_wdt_probe(struct 
 platform_device *pdev)
 ????????? else if (!strcmp(reset_type, "system"))

Signature · 1 line

2.31.1