Add ASPEED watchdog device tree properties

Describe device tree optional properties:

* aspeed,arm-reet - ARM CPU reset on signal
* aspeed,soc-reset - SOC reset on signal
* aspeed,sys-reset - System reset on signal
Disabling system reset may be required in situations where one of the other watchdog engines in the system is responsible for this.
* aspeed,interrupt - Interrupt CPU on signal
* aspeed,external-signal - Generate external signal (WDT1 and WDT2 only)
* aspeed,alt-boot - Boot from alternate block on signal

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Add 'aspeed,' prefix to all optional properties
- Add arm-reset, soc-reset, interrupt, alt-boot properties

---
 .../devicetree/bindings/watchdog/aspeed-wdt.txt    | 25 ++++++++++++++++++++++
 1 file changed, 25 insertions(+)

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +19 -0

index c5e74d7..555b8b4 100644
@@ -8,9 +8,34 @@ Required properties:
  - reg: physical base address of the controller and length of memory mapped
    region
 
+Optional properties:
+   Signal behavior - Whenever a timeout occurs, the watchdog can be programmed
+   to generate 6 types of signals:
+
+ - aspeed,arm-reset:  If property is present then reset ARM CPU only.
+
+ - aspeed,soc-reset:  If property is present then reset SOC.
+
+ - aspeed,sys-reset:  If property is present then reset the entire chip.
+                      In cases where one of the other watchdog engines
+                      in the system is responsible for system reset it
+                      may be required to not specify this property.
+
+ - aspeed,interrupt:  If property is present then interrupt CPU.
+
+ - aspeed,external-signal: If property is present then signal is sent to
+                           external reset counter (only WDT1 and WDT2).
+ - aspeed,alt-boot:    If property is present then boot from alternate block.
+
 Example:

Quoted 49 lines · Christopher Bostic

Describe device tree optional properties:

* aspeed,arm-reet - ARM CPU reset on signal
* aspeed,soc-reset - SOC reset on signal
* aspeed,sys-reset - System reset on signal
Disabling system reset may be required in situations where one of the other watchdog engines in the system is responsible for this.
* aspeed,interrupt - Interrupt CPU on signal
* aspeed,external-signal - Generate external signal (WDT1 and WDT2 only)
* aspeed,alt-boot - Boot from alternate block on signal

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Add 'aspeed,' prefix to all optional properties
- Add arm-reset, soc-reset, interrupt, alt-boot properties

---
  .../devicetree/bindings/watchdog/aspeed-wdt.txt    | 25 ++++++++++++++++++++++
  1 file changed, 25 insertions(+)

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +19 -0

index c5e74d7..555b8b4 100644
@@ -8,9 +8,34 @@ Required properties:
   - reg: physical base address of the controller and length of memory mapped
     region
 
+Optional properties:
+   Signal behavior - Whenever a timeout occurs, the watchdog can be programmed
+   to generate 6 types of signals:
+
+ - aspeed,arm-reset:  If property is present then reset ARM CPU only.
+
+ - aspeed,soc-reset:  If property is present then reset SOC.
+
+ - aspeed,sys-reset:  If property is present then reset the entire chip.
+                      In cases where one of the other watchdog engines
+                      in the system is responsible for system reset it
+                      may be required to not specify this property.
+
+ - aspeed,interrupt:  If property is present then interrupt CPU.
+
+ - aspeed,external-signal: If property is present then signal is sent to
+                           external reset counter (only WDT1 and WDT2).
+ - aspeed,alt-boot:    If property is present then boot from alternate block.
+
  Example:
 

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt Required properties: · line 40

Quoted 9 lines

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +6 -0

  	wdt1: watchdog@1e785000 {
  		compatible = "aspeed,ast2400-wdt";
  		reg = <0x1e785000 0x1c>;
+		aspeed,arm-reset;
+		aspeed,soc-reset;
+		aspeed,sys-reset;
+		aspeed,interrupt;
+		aspeed,external-signal;
+		aspeed,alt-boot;

Is that a bit mask or a value ? I would have thought that, for example, a complete system reset would include the SoC reset, and a SoC reset would include the ARM reset. Generating an interrupt while at the same time resetting the system (or part of it) doesn't seem to make much sense either.

Guenter

Quoted 54 lines · Guenter Roeck

Quoted 53 lines · Christopher Bostic

Describe device tree optional properties:

* aspeed,arm-reet - ARM CPU reset on signal
* aspeed,soc-reset - SOC reset on signal
* aspeed,sys-reset - System reset on signal
Disabling system reset may be required in situations where one of the other watchdog engines in the system is responsible for this.
* aspeed,interrupt - Interrupt CPU on signal
* aspeed,external-signal - Generate external signal (WDT1 and WDT2 only)
* aspeed,alt-boot - Boot from alternate block on signal

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Add 'aspeed,' prefix to all optional properties
- Add arm-reset, soc-reset, interrupt, alt-boot properties

---
 .../devicetree/bindings/watchdog/aspeed-wdt.txt    | 25 ++++++++++++++++++++++
 1 file changed, 25 insertions(+)

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +22 -0

index c5e74d7..555b8b4 100644
@@ -8,9 +8,34 @@ Required properties:
  - reg: physical base address of the controller and length of memory mapped
    region
+Optional properties:
+   Signal behavior - Whenever a timeout occurs, the watchdog can be programmed
+   to generate 6 types of signals:
+
+ - aspeed,arm-reset:  If property is present then reset ARM CPU only.
+
+ - aspeed,soc-reset:  If property is present then reset SOC.
+
+ - aspeed,sys-reset:  If property is present then reset the entire chip.
+                      In cases where one of the other watchdog engines
+                      in the system is responsible for system reset it
+                      may be required to not specify this property.
+
+ - aspeed,interrupt:  If property is present then interrupt CPU.
+
+ - aspeed,external-signal: If property is present then signal is sent to
+                           external reset counter (only WDT1 and WDT2).
+ - aspeed,alt-boot:    If property is present then boot from alternate block.
+
 Example:
 	wdt1: watchdog@1e785000 {
 		compatible = "aspeed,ast2400-wdt";
 		reg = <0x1e785000 0x1c>;
+		aspeed,arm-reset;
+		aspeed,soc-reset;
+		aspeed,sys-reset;

Quoted 8 lines

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt Required properties: · line 40

Quoted 3 lines

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +3 -0

+		aspeed,interrupt;
+		aspeed,external-signal;
+		aspeed,alt-boot;

Is that a bit mask or a value ? I would have thought that, for example, a complete system reset would include the SoC reset, and a SoC reset would include the ARM reset. Generating an interrupt while at the same time resetting the system (or part of it) doesn't seem to make much sense either.

No these aren't bitmasks. The example was intended to indicate what could
be used.
In practice only a subset of each of these properties would make any sense. How
would you suggest the example be formatted to convey that? Multiple examples I suppose.

Quoted 64 lines · Christopher Bostic

Quoted 54 lines · Guenter Roeck

Quoted 53 lines · Christopher Bostic

Describe device tree optional properties:

* aspeed,arm-reet - ARM CPU reset on signal
* aspeed,soc-reset - SOC reset on signal
* aspeed,sys-reset - System reset on signal
Disabling system reset may be required in situations where one of the other watchdog engines in the system is responsible for this.
* aspeed,interrupt - Interrupt CPU on signal
* aspeed,external-signal - Generate external signal (WDT1 and WDT2 only)
* aspeed,alt-boot - Boot from alternate block on signal

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Add 'aspeed,' prefix to all optional properties
- Add arm-reset, soc-reset, interrupt, alt-boot properties

---
  .../devicetree/bindings/watchdog/aspeed-wdt.txt    | 25 ++++++++++++++++++++++
  1 file changed, 25 insertions(+)

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +22 -0

index c5e74d7..555b8b4 100644
@@ -8,9 +8,34 @@ Required properties:
   - reg: physical base address of the controller and length of memory mapped
     region
+Optional properties:
+   Signal behavior - Whenever a timeout occurs, the watchdog can be programmed
+   to generate 6 types of signals:
+
+ - aspeed,arm-reset:  If property is present then reset ARM CPU only.
+
+ - aspeed,soc-reset:  If property is present then reset SOC.
+
+ - aspeed,sys-reset:  If property is present then reset the entire chip.
+                      In cases where one of the other watchdog engines
+                      in the system is responsible for system reset it
+                      may be required to not specify this property.
+
+ - aspeed,interrupt:  If property is present then interrupt CPU.
+
+ - aspeed,external-signal: If property is present then signal is sent to
+                           external reset counter (only WDT1 and WDT2).
+ - aspeed,alt-boot:    If property is present then boot from alternate block.
+
  Example:
  	wdt1: watchdog@1e785000 {
  		compatible = "aspeed,ast2400-wdt";
  		reg = <0x1e785000 0x1c>;
+		aspeed,arm-reset;
+		aspeed,soc-reset;
+		aspeed,sys-reset;

Quoted 8 lines

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt Required properties: · line 40

Quoted 3 lines

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +3 -0

+		aspeed,interrupt;
+		aspeed,external-signal;
+		aspeed,alt-boot;

Is that a bit mask or a value ? I would have thought that, for example, a complete system reset would include the SoC reset, and a SoC reset would include the ARM reset. Generating an interrupt while at the same time resetting the system (or part of it) doesn't seem to make much sense either.

Quoted 7 lines

No these aren't bitmasks. The example was intended to indicate what could
be used.
In practice only a subset of each of these properties would make any sense. How
would you suggest the example be formatted to convey that? Multiple examples I suppose.

I would just pick one (which is perfectly fine). After all, it is an example.

Reminds me: Is there a default (eg the chip's default configuration) ? In other words, what is expected to happen if none of the properties is specified ?

Thanks,
Guenter

Quoted 74 lines · Guenter Roeck

Quoted 64 lines · Christopher Bostic

Quoted 54 lines · Guenter Roeck

Quoted 53 lines · Christopher Bostic

Describe device tree optional properties:

* aspeed,arm-reet - ARM CPU reset on signal
* aspeed,soc-reset - SOC reset on signal
* aspeed,sys-reset - System reset on signal
Disabling system reset may be required in situations where one of the other watchdog engines in the system is responsible for this.
* aspeed,interrupt - Interrupt CPU on signal
* aspeed,external-signal - Generate external signal (WDT1 and WDT2 only)
* aspeed,alt-boot - Boot from alternate block on signal

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Add 'aspeed,' prefix to all optional properties
- Add arm-reset, soc-reset, interrupt, alt-boot properties

---
 .../devicetree/bindings/watchdog/aspeed-wdt.txt    | 25 ++++++++++++++++++++++
 1 file changed, 25 insertions(+)

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +22 -0

index c5e74d7..555b8b4 100644
@@ -8,9 +8,34 @@ Required properties:
  - reg: physical base address of the controller and length of memory mapped
    region
+Optional properties:
+   Signal behavior - Whenever a timeout occurs, the watchdog can be programmed
+   to generate 6 types of signals:
+
+ - aspeed,arm-reset:  If property is present then reset ARM CPU only.
+
+ - aspeed,soc-reset:  If property is present then reset SOC.
+
+ - aspeed,sys-reset:  If property is present then reset the entire chip.
+                      In cases where one of the other watchdog engines
+                      in the system is responsible for system reset it
+                      may be required to not specify this property.
+
+ - aspeed,interrupt:  If property is present then interrupt CPU.
+
+ - aspeed,external-signal: If property is present then signal is sent to
+                           external reset counter (only WDT1 and WDT2).
+ - aspeed,alt-boot:    If property is present then boot from alternate block.
+
 Example:
 	wdt1: watchdog@1e785000 {
 		compatible = "aspeed,ast2400-wdt";
 		reg = <0x1e785000 0x1c>;
+		aspeed,arm-reset;
+		aspeed,soc-reset;
+		aspeed,sys-reset;

Quoted 8 lines

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt Required properties: · line 40

Quoted 3 lines

Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt +3 -0

+		aspeed,interrupt;
+		aspeed,external-signal;
+		aspeed,alt-boot;

Is that a bit mask or a value ? I would have thought that, for example, a complete system reset would include the SoC reset, and a SoC reset would include the ARM reset. Generating an interrupt while at the same time resetting the system (or part of it) doesn't seem to make much sense either.

Quoted 7 lines

No these aren't bitmasks. The example was intended to indicate what could
be used.
In practice only a subset of each of these properties would make any sense. How
would you suggest the example be formatted to convey that? Multiple examples I suppose.

I would just pick one (which is perfectly fine). After all, it is an example.

Quoted 3 lines

Reminds me: Is there a default (eg the chip's default configuration) ? In other words, what is expected to happen if none of the properties is specified ?

Default was to enable SOC reset (parameter aspeed,soc-reset) and system reset (aspeed,sys-reset). Based on your comments in patch v2 2/2 it would be necessary for backwards compatibility to preserve that default behavior. So it seems the optional parameters should be inverted for these:
no-soc-reset, no-sys-reset.

Reference the system device tree when configuring the watchdog engines. Set external signal mode on timeout if specified. Set system reset on timeout if specified.

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Change of_get_property() to of_property_read_bool()
- Remove redundant check for NULL struct device_node pointer
- Optional property names now start with prefix 'aspeed,'

---
  drivers/watchdog/aspeed_wdt.c | 13 +++++++++++--
  1 file changed, 11 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +1 -0

index 1c65258..71ce5f5 100644
@@ -140,6 +140,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
  {
  	struct aspeed_wdt *wdt;
  	struct resource *res;
+	struct device_node *np;
  	int ret;
 
  	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);

@@ -170,8 +171,16 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
  	 * the SOC and not the full chip

Quoted 33 lines · Christopher Bostic

Reference the system device tree when configuring the watchdog engines. Set external signal mode on timeout if specified. Set system reset on timeout if specified.

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Change of_get_property() to of_property_read_bool()
- Remove redundant check for NULL struct device_node pointer
- Optional property names now start with prefix 'aspeed,'

---
  drivers/watchdog/aspeed_wdt.c | 13 +++++++++++--
  1 file changed, 11 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +2 -2

index 1c65258..71ce5f5 100644
@@ -140,6 +140,7 @@ static int aspeed_wdt_probe(struct 
 platform_device *pdev)
  {
      struct aspeed_wdt *wdt;
      struct resource *res;
+    struct device_node *np;
      int ret;
        wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);

@@ -170,8 +171,16 @@ static int aspeed_wdt_probe(struct 
 platform_device *pdev)
       * the SOC and not the full chip
       */
      wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
-        WDT_CTRL_1MHZ_CLK |
-        WDT_CTRL_RESET_SYSTEM;
+        WDT_CTRL_1MHZ_CLK;

drivers/watchdog/aspeed_wdt.c static int aspeed_wdt_probe(struct platform_device *pdev) · line 179

Quoted 5 lines

drivers/watchdog/aspeed_wdt.c +5 -0

+
+    np = pdev->dev.of_node;
+    if (of_property_read_bool(np, "aspeed,sys-reset"))
+        wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
+

For backward compatibility, this should default to WDT_CTRL_RESET_SYSTEM if no optional property is provided.

drivers/watchdog/aspeed_wdt.c static int aspeed_wdt_probe(struct platform_device *pdev) · line 186

Quoted 7 lines

drivers/watchdog/aspeed_wdt.c +4 -0

+    if (of_property_read_bool(np, "aspeed,external-signal"))
+        wdt->ctrl |= WDT_CTRL_WDT_EXT;
+
+    writel(wdt->ctrl, wdt->base + WDT_CTRL);
        if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
          aspeed_wdt_start(&wdt->wdd);

Quoted 35 lines · Guenter Roeck

Quoted 34 lines · Christopher Bostic

Reference the system device tree when configuring the watchdog engines. Set external signal mode on timeout if specified. Set system reset on timeout if specified.

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Change of_get_property() to of_property_read_bool()
- Remove redundant check for NULL struct device_node pointer
- Optional property names now start with prefix 'aspeed,'

---
 drivers/watchdog/aspeed_wdt.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +2 -2

index 1c65258..71ce5f5 100644
@@ -140,6 +140,7 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
 {
     struct aspeed_wdt *wdt;
     struct resource *res;
+    struct device_node *np;
     int ret;
       wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);

@@ -170,8 +171,16 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
      * the SOC and not the full chip
      */
     wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
-        WDT_CTRL_1MHZ_CLK |
-        WDT_CTRL_RESET_SYSTEM;
+        WDT_CTRL_1MHZ_CLK;

Quoted 9 lines

drivers/watchdog/aspeed_wdt.c static int aspeed_wdt_probe(struct platform_device *pdev) · line 179

Quoted 5 lines

drivers/watchdog/aspeed_wdt.c +5 -0

+
+    np = pdev->dev.of_node;
+    if (of_property_read_bool(np, "aspeed,sys-reset"))
+        wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
+

For backward compatibility, this should default to WDT_CTRL_RESET_SYSTEM if no optional property is provided.

I had the logic inverted for this property in a previous patch. The property was 'no-system-reset' so that when not present the default was to
set WDT_CTRL_RESET_SYSTEM. As it is in this patch, the only way to
indicate that no system reset is to be done is to not specify the property. No system reset is desired under circumstances when another wdt engine is to
be responsible for this. Given the issue with backward compatibility
that's not a solution. Given this, would creating a property 'no-system-reset' be acceptable?

Thanks,
Chris

Quoted 8 lines

Quoted 7 lines

drivers/watchdog/aspeed_wdt.c +4 -0

+    if (of_property_read_bool(np, "aspeed,external-signal"))
+        wdt->ctrl |= WDT_CTRL_WDT_EXT;
+
+    writel(wdt->ctrl, wdt->base + WDT_CTRL);
       if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
         aspeed_wdt_start(&wdt->wdd);

Quoted 45 lines · Christopher Bostic

Quoted 34 lines · Guenter Roeck

Quoted 33 lines · Christopher Bostic

Reference the system device tree when configuring the watchdog engines. Set external signal mode on timeout if specified. Set system reset on timeout if specified.

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Change of_get_property() to of_property_read_bool()
- Remove redundant check for NULL struct device_node pointer
- Optional property names now start with prefix 'aspeed,'

---
  drivers/watchdog/aspeed_wdt.c | 13 +++++++++++--
  1 file changed, 11 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +1 -2

index 1c65258..71ce5f5 100644
@@ -140,6 +140,7 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
  {
      struct aspeed_wdt *wdt;
      struct resource *res;
+    struct device_node *np;
      int ret;
        wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);

@@ -170,8 +171,16 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
       * the SOC and not the full chip
       */
      wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
-        WDT_CTRL_1MHZ_CLK |
-        WDT_CTRL_RESET_SYSTEM;

Quoted 9 lines

drivers/watchdog/aspeed_wdt.c static int aspeed_wdt_probe(struct platform_device *pdev) · line 179

Quoted 6 lines

drivers/watchdog/aspeed_wdt.c +6 -0

+        WDT_CTRL_1MHZ_CLK;
+
+    np = pdev->dev.of_node;
+    if (of_property_read_bool(np, "aspeed,sys-reset"))
+        wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
+

For backward compatibility, this should default to WDT_CTRL_RESET_SYSTEM if no optional property is provided.

Quoted 9 lines

I had the logic inverted for this property in a previous patch. The property was 'no-system-reset' so that when not present the default was to
set WDT_CTRL_RESET_SYSTEM. As it is in this patch, the only way to
indicate that no system reset is to be done is to not specify the property. No system reset is desired under circumstances when another wdt engine is to
be responsible for this. Given the issue with backward compatibility
that's not a solution. Given this, would creating a property 'no-system-reset' be acceptable?

Sorry, I fail to see the problem. There are half a dozen properties. What is the problem with having a default if no property is specified ? Your default is "do nothing", which does not really make any sense to me. If the user wants the watchdog to do nothing, the simple means to accomplish that would be to not instantiate it.

Sure, that means specifying "system-reset" is redundant, but I don't see a problem with that either. But I do see a problem with loading a watchdog driver that doesn't do anything.

If there is really some use case where it makes sense to load a watchdog driver and have it do nothing, please explain and provide a respective devicetree property. "aspeed,do-nothing" (or whatever similar) doesn't sound good, but at least makes it obvious that the driver isn't doing anything besides creating a false sense of "the system is watchdog protected".

Thanks,
Guenter

Quoted 10 lines

Thanks,
Chris

Quoted 7 lines

Quoted 7 lines

drivers/watchdog/aspeed_wdt.c +4 -0

+    if (of_property_read_bool(np, "aspeed,external-signal"))
+        wdt->ctrl |= WDT_CTRL_WDT_EXT;
+
+    writel(wdt->ctrl, wdt->base + WDT_CTRL);
        if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
          aspeed_wdt_start(&wdt->wdd);

Quoted 65 lines · Guenter Roeck

Quoted 45 lines · Christopher Bostic

Quoted 34 lines · Guenter Roeck

Quoted 33 lines · Christopher Bostic

Reference the system device tree when configuring the watchdog engines. Set external signal mode on timeout if specified. Set system reset on timeout if specified.

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Change of_get_property() to of_property_read_bool()
- Remove redundant check for NULL struct device_node pointer
- Optional property names now start with prefix 'aspeed,'

---
 drivers/watchdog/aspeed_wdt.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +1 -2

index 1c65258..71ce5f5 100644
@@ -140,6 +140,7 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
 {
     struct aspeed_wdt *wdt;
     struct resource *res;
+    struct device_node *np;
     int ret;
       wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);

@@ -170,8 +171,16 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
      * the SOC and not the full chip
      */
     wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
-        WDT_CTRL_1MHZ_CLK |
-        WDT_CTRL_RESET_SYSTEM;

Quoted 9 lines

drivers/watchdog/aspeed_wdt.c static int aspeed_wdt_probe(struct platform_device *pdev) · line 179

Quoted 6 lines

drivers/watchdog/aspeed_wdt.c +6 -0

+        WDT_CTRL_1MHZ_CLK;
+
+    np = pdev->dev.of_node;
+    if (of_property_read_bool(np, "aspeed,sys-reset"))
+        wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
+

For backward compatibility, this should default to WDT_CTRL_RESET_SYSTEM if no optional property is provided.

Quoted 9 lines

I had the logic inverted for this property in a previous patch. The property was 'no-system-reset' so that when not present the default was to
set WDT_CTRL_RESET_SYSTEM. As it is in this patch, the only way to
indicate that no system reset is to be done is to not specify the property. No system reset is desired under circumstances when another wdt engine is to
be responsible for this. Given the issue with backward compatibility
that's not a solution. Given this, would creating a property 'no-system-reset' be acceptable?

Sorry, I fail to see the problem. There are half a dozen properties. What is the problem with having a default if no property is specified ? Your default is "do nothing", which does not really make any sense to me. If the user wants the watchdog to do nothing, the simple means to accomplish that would be to not instantiate it.

Sure, that means specifying "system-reset" is redundant, but I don't see a problem with that either. But I do see a problem with loading a watchdog driver that doesn't do anything.

Quoted 5 lines

If there is really some use case where it makes sense to load a watchdog driver and have it do nothing, please explain and provide a respective devicetree property. "aspeed,do-nothing" (or whatever similar) doesn't sound good, but at least makes it obvious that the driver isn't doing anything besides creating a false sense of "the system is watchdog protected".

If system-reset is not wanted there are other properties that might still be needed, for example
ARM reset only. We'd still want to instantiate it.

Thanks,
Chris

Quoted 15 lines

Thanks,
Guenter

Quoted 10 lines

Thanks,
Chris

Quoted 7 lines

Quoted 7 lines

drivers/watchdog/aspeed_wdt.c +4 -0

+    if (of_property_read_bool(np, "aspeed,external-signal"))
+        wdt->ctrl |= WDT_CTRL_WDT_EXT;
+
+    writel(wdt->ctrl, wdt->base + WDT_CTRL);
       if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
         aspeed_wdt_start(&wdt->wdd);

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Quoted 71 lines · Christopher Bostic

Quoted 69 lines · Guenter Roeck

Quoted 44 lines · Christopher Bostic

Quoted 34 lines · Guenter Roeck

Quoted 33 lines · Christopher Bostic

Reference the system device tree when configuring the watchdog engines. Set external signal mode on timeout if specified. Set system reset on timeout if specified.

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Change of_get_property() to of_property_read_bool()
- Remove redundant check for NULL struct device_node pointer
- Optional property names now start with prefix 'aspeed,'

---
  drivers/watchdog/aspeed_wdt.c | 13 +++++++++++--
  1 file changed, 11 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +1 -2

index 1c65258..71ce5f5 100644
@@ -140,6 +140,7 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
  {
      struct aspeed_wdt *wdt;
      struct resource *res;
+    struct device_node *np;
      int ret;
        wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);

@@ -170,8 +171,16 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
       * the SOC and not the full chip
       */
      wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
-        WDT_CTRL_1MHZ_CLK |
-        WDT_CTRL_RESET_SYSTEM;

Quoted 9 lines

drivers/watchdog/aspeed_wdt.c static int aspeed_wdt_probe(struct platform_device *pdev) · line 179

Quoted 6 lines

drivers/watchdog/aspeed_wdt.c +6 -0

+        WDT_CTRL_1MHZ_CLK;
+
+    np = pdev->dev.of_node;
+    if (of_property_read_bool(np, "aspeed,sys-reset"))
+        wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
+

For backward compatibility, this should default to WDT_CTRL_RESET_SYSTEM if no optional property is provided.

Quoted 9 lines

I had the logic inverted for this property in a previous patch. The property was 'no-system-reset' so that when not present the default was to
set WDT_CTRL_RESET_SYSTEM. As it is in this patch, the only way to
indicate that no system reset is to be done is to not specify the property. No system reset is desired under circumstances when another wdt engine is to
be responsible for this. Given the issue with backward compatibility
that's not a solution. Given this, would creating a property 'no-system-reset' be acceptable?

Sorry, I fail to see the problem. There are half a dozen properties. What is the problem with having a default if no property is specified ? Your default is "do nothing", which does not really make any sense to me. If the user wants the watchdog to do nothing, the simple means to accomplish that would be to not instantiate it.

Sure, that means specifying "system-reset" is redundant, but I don't see a problem with that either. But I do see a problem with loading a watchdog driver that doesn't do anything.

If there is really some use case where it makes sense to load a watchdog driver and have it do nothing, please explain and provide a respective devicetree property. "aspeed,do-nothing" (or whatever similar) doesn't sound good, but at least makes it obvious that the driver isn't doing anything besides creating a false sense of "the system is watchdog protected".

Quoted 4 lines

If system-reset is not wanted there are other properties that might still be needed, for example
ARM reset only. We'd still want to instantiate it.

But then you would presumably specify that property, so there would be one. The question here is what to do if _no_ property is provided.

Sorry, I don't get your point.

Guenter

Quoted 20 lines

Thanks,
Chris

Quoted 14 lines

Thanks,
Guenter

Quoted 10 lines

Thanks,
Chris

Quoted 7 lines

Quoted 7 lines

drivers/watchdog/aspeed_wdt.c +4 -0

+    if (of_property_read_bool(np, "aspeed,external-signal"))
+        wdt->ctrl |= WDT_CTRL_WDT_EXT;
+
+    writel(wdt->ctrl, wdt->base + WDT_CTRL);
        if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
          aspeed_wdt_start(&wdt->wdd);

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Quoted 72 lines · Guenter Roeck

Quoted 71 lines · Christopher Bostic

Quoted 69 lines · Guenter Roeck

Quoted 44 lines · Christopher Bostic

Quoted 34 lines · Guenter Roeck

Quoted 33 lines · Christopher Bostic

Reference the system device tree when configuring the watchdog engines. Set external signal mode on timeout if specified. Set system reset on timeout if specified.

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Change of_get_property() to of_property_read_bool()
- Remove redundant check for NULL struct device_node pointer
- Optional property names now start with prefix 'aspeed,'

---
 drivers/watchdog/aspeed_wdt.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +1 -2

index 1c65258..71ce5f5 100644
@@ -140,6 +140,7 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
 {
     struct aspeed_wdt *wdt;
     struct resource *res;
+    struct device_node *np;
     int ret;
       wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);

@@ -170,8 +171,16 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
      * the SOC and not the full chip
      */
     wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
-        WDT_CTRL_1MHZ_CLK |
-        WDT_CTRL_RESET_SYSTEM;

Quoted 9 lines

drivers/watchdog/aspeed_wdt.c static int aspeed_wdt_probe(struct platform_device · line 180

Quoted 6 lines

drivers/watchdog/aspeed_wdt.c +6 -0

+        WDT_CTRL_1MHZ_CLK;
+
+    np = pdev->dev.of_node;
+    if (of_property_read_bool(np, "aspeed,sys-reset"))
+        wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
+

For backward compatibility, this should default to WDT_CTRL_RESET_SYSTEM if no optional property is provided.

Quoted 9 lines

I had the logic inverted for this property in a previous patch. The property was 'no-system-reset' so that when not present the default was to
set WDT_CTRL_RESET_SYSTEM. As it is in this patch, the only way to
indicate that no system reset is to be done is to not specify the property. No system reset is desired under circumstances when another wdt engine is to
be responsible for this. Given the issue with backward compatibility
that's not a solution. Given this, would creating a property 'no-system-reset' be acceptable?

Sorry, I fail to see the problem. There are half a dozen properties. What is the problem with having a default if no property is specified ? Your default is "do nothing", which does not really make any sense to me. If the user wants the watchdog to do nothing, the simple means to accomplish that would be to not instantiate it.

Sure, that means specifying "system-reset" is redundant, but I don't see a problem with that either. But I do see a problem with loading a watchdog driver that doesn't do anything.

If there is really some use case where it makes sense to load a watchdog driver and have it do nothing, please explain and provide a respective devicetree property. "aspeed,do-nothing" (or whatever similar) doesn't sound good, but at least makes it obvious that the driver isn't doing anything besides creating a false sense of "the system is watchdog protected".

Quoted 6 lines

Quoted 4 lines

If system-reset is not wanted there are other properties that might still be needed, for example
ARM reset only. We'd still want to instantiate it.

But then you would presumably specify that property, so there would be one. The question here is what to do if _no_ property is provided.

I agree that the default should be to perform a system reset when no
property is provided. I will make that change. Additionally for backwards
compatibility the SOC reset should be enabled by default when no property is
provided. The other parameters are not configured in the watchdog control
register if no property is provided.

There is still a need to to configure for no system reset. For example, optional parameter 'aspeed,no-sys-reset' that can be specified if system reset is to be disabled. In addition the default 'SOC reset enabled' behavior could be disabled with an optional parameter 'aspeed,no-soc-reset'.

Why would there even be a need configure for no system reset? The external mode 'wdt ext: External signal enable after timeout' can be sent off chip even if system reset is disabled. The watchdog is doing something in this case and would require wdt instantiation.

Hope this is more clear, sorry for the confusion.

Thanks,
-Chris AST2500 Software Programming Guide

Quoted 24 lines

Sorry, I don't get your point.

Guenter

Quoted 20 lines

Thanks,
Chris

Quoted 14 lines

Thanks,
Guenter

Quoted 10 lines

Thanks,
Chris

Quoted 7 lines

Quoted 7 lines

drivers/watchdog/aspeed_wdt.c +4 -0

+    if (of_property_read_bool(np, "aspeed,external-signal"))
+        wdt->ctrl |= WDT_CTRL_WDT_EXT;
+
+    writel(wdt->ctrl, wdt->base + WDT_CTRL);
       if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
         aspeed_wdt_start(&wdt->wdd);

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Quoted 90 lines · Christopher Bostic

Quoted 71 lines · Guenter Roeck

Quoted 70 lines · Christopher Bostic

Quoted 69 lines · Guenter Roeck

Quoted 44 lines · Christopher Bostic

Quoted 34 lines · Guenter Roeck

Quoted 33 lines · Christopher Bostic

Reference the system device tree when configuring the watchdog engines. Set external signal mode on timeout if specified. Set system reset on timeout if specified.

Signed-off-by Christopher Bostic <[email protected]>

---
v2 - Change of_get_property() to of_property_read_bool()
- Remove redundant check for NULL struct device_node pointer
- Optional property names now start with prefix 'aspeed,'

---
  drivers/watchdog/aspeed_wdt.c | 13 +++++++++++--
  1 file changed, 11 insertions(+), 2 deletions(-)

drivers/watchdog/aspeed_wdt.c +1 -2

index 1c65258..71ce5f5 100644
@@ -140,6 +140,7 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
  {
      struct aspeed_wdt *wdt;
      struct resource *res;
+    struct device_node *np;
      int ret;
        wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);

@@ -170,8 +171,16 @@ static int aspeed_wdt_probe(struct platform_device
 *pdev)
       * the SOC and not the full chip
       */
      wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
-        WDT_CTRL_1MHZ_CLK |
-        WDT_CTRL_RESET_SYSTEM;

Quoted 9 lines

drivers/watchdog/aspeed_wdt.c static int aspeed_wdt_probe(struct platform_device · line 180

Quoted 6 lines

drivers/watchdog/aspeed_wdt.c +6 -0

+        WDT_CTRL_1MHZ_CLK;
+
+    np = pdev->dev.of_node;
+    if (of_property_read_bool(np, "aspeed,sys-reset"))
+        wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
+

For backward compatibility, this should default to WDT_CTRL_RESET_SYSTEM if no optional property is provided.

Quoted 9 lines

I had the logic inverted for this property in a previous patch. The property was 'no-system-reset' so that when not present the default was to
set WDT_CTRL_RESET_SYSTEM. As it is in this patch, the only way to
indicate that no system reset is to be done is to not specify the property. No system reset is desired under circumstances when another wdt engine is to
be responsible for this. Given the issue with backward compatibility
that's not a solution. Given this, would creating a property 'no-system-reset' be acceptable?

Sorry, I fail to see the problem. There are half a dozen properties. What is the problem with having a default if no property is specified ? Your default is "do nothing", which does not really make any sense to me. If the user wants the watchdog to do nothing, the simple means to accomplish that would be to not instantiate it.

Sure, that means specifying "system-reset" is redundant, but I don't see a problem with that either. But I do see a problem with loading a watchdog driver that doesn't do anything.

If there is really some use case where it makes sense to load a watchdog driver and have it do nothing, please explain and provide a respective devicetree property. "aspeed,do-nothing" (or whatever similar) doesn't sound good, but at least makes it obvious that the driver isn't doing anything besides creating a false sense of "the system is watchdog protected".

Quoted 6 lines

Quoted 4 lines

If system-reset is not wanted there are other properties that might still be needed, for example
ARM reset only. We'd still want to instantiate it.

But then you would presumably specify that property, so there would be one. The question here is what to do if _no_ property is provided.

I agree that the default should be to perform a system reset when no
property is provided. I will make that change. Additionally for backwards
compatibility the SOC reset should be enabled by default when no property is
provided. The other parameters are not configured in the watchdog control
register if no property is provided.

There is still a need to to configure for no system reset. For example, optional parameter 'aspeed,no-sys-reset' that can be specified if system reset is to be disabled. In addition the default 'SOC reset enabled' behavior could be disabled with an optional parameter 'aspeed,no-soc-reset'.

Quoted 5 lines

Why would there even be a need configure for no system reset? The external mode 'wdt ext: External signal enable after timeout' can be sent off chip even if system reset is disabled. The watchdog is doing something in this case and would require wdt instantiation.

Wouldn't that be "aspeed,external-signal" ?

Guenter

Quoted 28 lines

Hope this is more clear, sorry for the confusion.

Thanks,
-Chris AST2500 Software Programming Guide

Quoted 24 lines

Sorry, I don't get your point.

Guenter

Quoted 20 lines

Thanks,
Chris

Quoted 14 lines

Thanks,
Guenter

Quoted 10 lines

Thanks,
Chris

Quoted 7 lines

Quoted 7 lines

drivers/watchdog/aspeed_wdt.c +4 -0

+    if (of_property_read_bool(np, "aspeed,external-signal"))
+        wdt->ctrl |= WDT_CTRL_WDT_EXT;
+
+    writel(wdt->ctrl, wdt->base + WDT_CTRL);
        if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
          aspeed_wdt_start(&wdt->wdd);

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Quoted 8 lines

Quoted 7 lines

Why would there even be a need configure for no system reset? The external mode 'wdt ext: External signal enable after timeout' can be sent off chip even if system reset is disabled. The watchdog is doing something in this case and would require wdt instantiation.

Wouldn't that be "aspeed,external-signal" ?

Yes that optional parameter would need to be specified in that situation, as well as 'aspeed,no-system-reset'.