watchdog: mt7621: Set WDOG_HW_RUNNING, when watchdog is already running.

PATCH In review André Draszik 2 participants 7 messages Jan 10, 2018 – Jan 12, 2018

Subsystems (2)

Arm MediaTek Watchdog device drivers

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André Draszik

author

2018-01-10 12:13 UTC #0 lore raw

PATCH 1/2 watchdog: mt7621: Set WDOG_HW_RUNNING, when watchdog is already running.

This patch uses the new flag WDOG_HW_RUNNING in driver. According to the definition of this flag, it should be set if the watchdog hardware is enabled/running during boot before being opened here, e.g. due to a boot loader configuring the watchdog.

Given the watchdog driver core doesn't know what timeout was originally set by whoever started the watchdog (boot loader), we make sure to update the timeout in the hardware according to what the watchdog core thinks it is.

Signed-off-by André Draszik <[email protected]>

Cc Wim Van Sebroeck <[email protected]>

Cc Guenter Roeck <[email protected]>

Cc [email protected]

Cc John Crispin <[email protected]>

---
 drivers/watchdog/mt7621_wdt.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

drivers/watchdog/mt7621_wdt.c +16 -0

index db38f8017218..0eabea2d88a2 100644
@@ -105,6 +105,11 @@ static int mt7621_wdt_bootcause(void)
 	return 0;
 }
 
+static int mt7621_wdt_is_running(struct watchdog_device *w)
+{
+	return !!(rt_wdt_r32(TIMER_REG_TMR1CTL) & TMR1CTL_ENABLE);
+}
+
 static const struct watchdog_info mt7621_wdt_info = {
 	.identity = "Mediatek Watchdog",
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,

@@ -144,6 +149,17 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
 	watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout,
 			      &pdev->dev);
 	watchdog_set_nowayout(&mt7621_wdt_dev, nowayout);
+	if (mt7621_wdt_is_running(&mt7621_wdt_dev)) {
+		/* Make sure to apply timeout from wathdog_core, taking
+		   the prescaler of this driver here into account (the
+		   boot loader might be using a different prescaler).
+		   To avoid spurious resets because of different scaling,
+		   we first disable the watchdog, set the new prescaler
+		   and timeout, and then re-enable the watchdog. */
+		mt7621_wdt_stop(&mt7621_wdt_dev);
+		mt7621_wdt_start(&mt7621_wdt_dev);
+		set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status);
+	}
 
 	ret = watchdog_register_device(&mt7621_wdt_dev);

Signature · 1 line

2.15.1

André Draszik

author

2018-01-10 12:13 UTC #1 lore raw

PATCH 2/2 watchdog: mt7621: switch to using managed devm_watchdog_register_device()

This does the necessary cleanup on driver unload automatically.

Signed-off-by André Draszik <[email protected]>

Cc Wim Van Sebroeck <[email protected]>

Cc Guenter Roeck <[email protected]>

Cc [email protected]

Cc John Crispin <[email protected]>

---
 drivers/watchdog/mt7621_wdt.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

drivers/watchdog/mt7621_wdt.c +1 ~~-12~~

index 0eabea2d88a2..a04f49309188 100644
@@ -133,7 +133,6 @@ static struct watchdog_device mt7621_wdt_dev = {
 static int mt7621_wdt_probe(struct platform_device *pdev)
 {
 	struct resource *res;
-	int ret;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	mt7621_wdt_base = devm_ioremap_resource(&pdev->dev, res);

@@ -161,16 +160,7 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
 		set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status);
 	}
 
-	ret = watchdog_register_device(&mt7621_wdt_dev);
-
-	return 0;
-}
-
-static int mt7621_wdt_remove(struct platform_device *pdev)
-{
-	watchdog_unregister_device(&mt7621_wdt_dev);
-
-	return 0;
+	return devm_watchdog_register_device(&pdev->dev, &mt7621_wdt_dev);
 }
 
 static void mt7621_wdt_shutdown(struct platform_device *pdev)

@@ -186,7 +176,6 @@ MODULE_DEVICE_TABLE(of, mt7621_wdt_match);
 
 static struct platform_driver mt7621_wdt_driver = {
 	.probe		= mt7621_wdt_probe,
-	.remove		= mt7621_wdt_remove,
 	.shutdown	= mt7621_wdt_shutdown,
 	.driver		= {
 		.name		= KBUILD_MODNAME,

Signature · 1 line

2.15.1

Guenter Roeck

maintainer Reviewed-by on v1 2/2

2018-01-11 18:25 UTC #2 lore raw

Re: [PATCH 2/2] watchdog: mt7621: switch to using managed devm_watchdog_register_device()

Quoted 7 lines · André Draszik

This does the necessary cleanup on driver unload automatically.
Signed-off-by André Draszik <[email protected]>
Cc Wim Van Sebroeck <[email protected]>
Cc Guenter Roeck <[email protected]>
Cc [email protected]
Cc John Crispin <[email protected]>

Reviewed-by Guenter Roeck <[email protected]>

Quoted 49 lines

---
 drivers/watchdog/mt7621_wdt.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

drivers/watchdog/mt7621_wdt.c +1 ~~-12~~

index 0eabea2d88a2..a04f49309188 100644
@@ -133,7 +133,6 @@ static struct watchdog_device mt7621_wdt_dev = {
 static int mt7621_wdt_probe(struct platform_device *pdev)
 {
 	struct resource *res;
-	int ret;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	mt7621_wdt_base = devm_ioremap_resource(&pdev->dev, res);

@@ -161,16 +160,7 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
 		set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status);
 	}
 
-	ret = watchdog_register_device(&mt7621_wdt_dev);
-
-	return 0;
-}
-
-static int mt7621_wdt_remove(struct platform_device *pdev)
-{
-	watchdog_unregister_device(&mt7621_wdt_dev);
-
-	return 0;
+	return devm_watchdog_register_device(&pdev->dev, &mt7621_wdt_dev);
 }
 
 static void mt7621_wdt_shutdown(struct platform_device *pdev)

@@ -186,7 +176,6 @@ MODULE_DEVICE_TABLE(of, mt7621_wdt_match);
 
 static struct platform_driver mt7621_wdt_driver = {
 	.probe		= mt7621_wdt_probe,
-	.remove		= mt7621_wdt_remove,
 	.shutdown	= mt7621_wdt_shutdown,
 	.driver		= {
 		.name		= KBUILD_MODNAME,

Signature · 6 lines

2.15.1

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Guenter Roeck

maintainer

2018-01-11 18:24 UTC #3 lore raw

In reply to André Draszik

Quoted 37 lines · André Draszik

This patch uses the new flag WDOG_HW_RUNNING in driver. According to the definition of this flag, it should be set if the watchdog hardware is enabled/running during boot before being opened here, e.g. due to a boot loader configuring the watchdog.
Given the watchdog driver core doesn't know what timeout was originally set by whoever started the watchdog (boot loader), we make sure to update the timeout in the hardware according to what the watchdog core thinks it is.
Signed-off-by André Draszik <[email protected]>
Cc Wim Van Sebroeck <[email protected]>
Cc Guenter Roeck <[email protected]>
Cc [email protected]
Cc John Crispin <[email protected]>
---
 drivers/watchdog/mt7621_wdt.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
drivers/watchdog/mt7621_wdt.c +5 -0
index db38f8017218..0eabea2d88a2 100644
@@ -105,6 +105,11 @@ static int mt7621_wdt_bootcause(void)
 	return 0;
 }
 
+static int mt7621_wdt_is_running(struct watchdog_device *w)
+{
+	return !!(rt_wdt_r32(TIMER_REG_TMR1CTL) & TMR1CTL_ENABLE);
+}
+
 static const struct watchdog_info mt7621_wdt_info = {
 	.identity = "Mediatek Watchdog",
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,

drivers/watchdog/mt7621_wdt.c static int mt7621_wdt_probe(struct platform_device *pdev) · line 153

Quoted 5 lines

drivers/watchdog/mt7621_wdt.c +2 -0

@@ -144,6 +149,17 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
 	watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout,
 			      &pdev->dev);
 	watchdog_set_nowayout(&mt7621_wdt_dev, nowayout);
+	if (mt7621_wdt_is_running(&mt7621_wdt_dev)) {
+		/* Make sure to apply timeout from wathdog_core, taking

watchdog core

drivers/watchdog/mt7621_wdt.c static int mt7621_wdt_probe(struct platform_device *pdev) · line 158

Quoted 5 lines

drivers/watchdog/mt7621_wdt.c +5 -0

+		   the prescaler of this driver here into account (the
+		   boot loader might be using a different prescaler).
+		   To avoid spurious resets because of different scaling,
+		   we first disable the watchdog, set the new prescaler
+		   and timeout, and then re-enable the watchdog. */

Please use proper multi-line comments.

Quoted 14 lines

drivers/watchdog/mt7621_wdt.c +4 -0

+		mt7621_wdt_stop(&mt7621_wdt_dev);
+		mt7621_wdt_start(&mt7621_wdt_dev);
+		set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status);
+	}
 
 	ret = watchdog_register_device(&mt7621_wdt_dev);

Signature · 6 lines

2.15.1

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the body of a message to [email protected]
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André Draszik

author

2018-01-12 09:44 UTC #4 lore raw

PATCH v2 1/2 watchdog: mt7621: set WDOG_HW_RUNNING bit when appropriate

In reply to André Draszik

If the watchdog hardware is enabled/running during boot, e.g. due to a boot loader configuring it, we must tell the watchdog framework about this fact so that it can ping the watchdog until userspace opens the device and takes over control.

Do so using the WDOG_HW_RUNNING flag that exists for exactly that use-case.

Signed-off-by André Draszik <[email protected]>

Cc Wim Van Sebroeck <[email protected]>

Cc Guenter Roeck <[email protected]>

Cc [email protected]

Cc John Crispin <[email protected]>

---
Changes in v2:
- fix typo and proper multi-line comment
- update commit message to be clearer

---
 drivers/watchdog/mt7621_wdt.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

drivers/watchdog/mt7621_wdt.c +19 -0

index db38f8017218..eec57e5e1eae 100644
@@ -105,6 +105,11 @@ static int mt7621_wdt_bootcause(void)
 	return 0;
 }
 
+static int mt7621_wdt_is_running(struct watchdog_device *w)
+{
+	return !!(rt_wdt_r32(TIMER_REG_TMR1CTL) & TMR1CTL_ENABLE);
+}
+
 static const struct watchdog_info mt7621_wdt_info = {
 	.identity = "Mediatek Watchdog",
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,

@@ -144,6 +149,20 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
 	watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout,
 			      &pdev->dev);
 	watchdog_set_nowayout(&mt7621_wdt_dev, nowayout);
+	if (mt7621_wdt_is_running(&mt7621_wdt_dev)) {
+		/*
+		 * Make sure to apply timeout from watchdog core, taking
+		 * the prescaler of this driver here into account (the
+		 * boot loader might be using a different prescaler).
+		 *
+		 * To avoid spurious resets because of different scaling,
+		 * we first disable the watchdog, set the new prescaler
+		 * and timeout, and then re-enable the watchdog.
+		 */
+		mt7621_wdt_stop(&mt7621_wdt_dev);
+		mt7621_wdt_start(&mt7621_wdt_dev);
+		set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status);
+	}
 
 	ret = watchdog_register_device(&mt7621_wdt_dev);

Signature · 1 line

2.15.1

André Draszik

author

2018-01-12 09:44 UTC #5 lore raw

PATCH v2 2/2 watchdog: mt7621: switch to using managed devm_watchdog_register_device()

This does the necessary cleanup on driver unload automatically.

Signed-off-by André Draszik <[email protected]>

Reviewed-by Guenter Roeck <[email protected]>

Cc Wim Van Sebroeck <[email protected]>

Cc Guenter Roeck <[email protected]>

Cc [email protected]

Cc John Crispin <[email protected]>

---
Changes in v2:
- add reviewed-by

---
 drivers/watchdog/mt7621_wdt.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

drivers/watchdog/mt7621_wdt.c +1 ~~-12~~

index eec57e5e1eae..5c4a764717c4 100644
@@ -133,7 +133,6 @@ static struct watchdog_device mt7621_wdt_dev = {
 static int mt7621_wdt_probe(struct platform_device *pdev)
 {
 	struct resource *res;
-	int ret;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	mt7621_wdt_base = devm_ioremap_resource(&pdev->dev, res);

@@ -164,16 +163,7 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
 		set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status);
 	}
 
-	ret = watchdog_register_device(&mt7621_wdt_dev);
-
-	return 0;
-}
-
-static int mt7621_wdt_remove(struct platform_device *pdev)
-{
-	watchdog_unregister_device(&mt7621_wdt_dev);
-
-	return 0;
+	return devm_watchdog_register_device(&pdev->dev, &mt7621_wdt_dev);
 }
 
 static void mt7621_wdt_shutdown(struct platform_device *pdev)

@@ -189,7 +179,6 @@ MODULE_DEVICE_TABLE(of, mt7621_wdt_match);
 
 static struct platform_driver mt7621_wdt_driver = {
 	.probe		= mt7621_wdt_probe,
-	.remove		= mt7621_wdt_remove,
 	.shutdown	= mt7621_wdt_shutdown,
 	.driver		= {
 		.name		= KBUILD_MODNAME,

Signature · 1 line

2.15.1

Guenter Roeck

maintainer Reviewed-by on v2 1/2

2018-01-12 23:22 UTC #6 lore raw

Re: [PATCH v2 1/2] watchdog: mt7621: set WDOG_HW_RUNNING bit when appropriate

In reply to André Draszik

Quoted 14 lines · André Draszik

If the watchdog hardware is enabled/running during boot, e.g. due to a boot loader configuring it, we must tell the watchdog framework about this fact so that it can ping the watchdog until userspace opens the device and takes over control.
Do so using the WDOG_HW_RUNNING flag that exists for exactly that use-case.
Given the watchdog driver core doesn't know what timeout was originally set by whoever started the watchdog (boot loader), we make sure to update the timeout in the hardware according to what the watchdog core thinks it is.

Quoted 5 lines

Signed-off-by André Draszik <[email protected]>
Cc Wim Van Sebroeck <[email protected]>
Cc Guenter Roeck <[email protected]>
Cc [email protected]
Cc John Crispin <[email protected]>

Reviewed-by Guenter Roeck <[email protected]>

Quoted 49 lines

---
Changes in v2:
- fix typo and proper multi-line comment
- update commit message to be clearer

---
 drivers/watchdog/mt7621_wdt.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

drivers/watchdog/mt7621_wdt.c +19 -0

index db38f8017218..eec57e5e1eae 100644
@@ -105,6 +105,11 @@ static int mt7621_wdt_bootcause(void)
 	return 0;
 }
 
+static int mt7621_wdt_is_running(struct watchdog_device *w)
+{
+	return !!(rt_wdt_r32(TIMER_REG_TMR1CTL) & TMR1CTL_ENABLE);
+}
+
 static const struct watchdog_info mt7621_wdt_info = {
 	.identity = "Mediatek Watchdog",
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,

@@ -144,6 +149,20 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
 	watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout,
 			      &pdev->dev);
 	watchdog_set_nowayout(&mt7621_wdt_dev, nowayout);
+	if (mt7621_wdt_is_running(&mt7621_wdt_dev)) {
+		/*
+		 * Make sure to apply timeout from watchdog core, taking
+		 * the prescaler of this driver here into account (the
+		 * boot loader might be using a different prescaler).
+		 *
+		 * To avoid spurious resets because of different scaling,
+		 * we first disable the watchdog, set the new prescaler
+		 * and timeout, and then re-enable the watchdog.
+		 */
+		mt7621_wdt_stop(&mt7621_wdt_dev);
+		mt7621_wdt_start(&mt7621_wdt_dev);
+		set_bit(WDOG_HW_RUNNING, &mt7621_wdt_dev.status);
+	}
 
 	ret = watchdog_register_device(&mt7621_wdt_dev);

Signature · 1 line

2.15.1