Re: [PATCH 4.4 70/97] rtc: ds1374: wdt: Fix issue with timeout scaling from secs to wdt ticks

[Ben Hutchings]

On Fri, 2018-03-23 at 10:54 +0100, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> --
> 
> From: Moritz Fischer 
> 
> 
> [ Upstream commit 453d0744f6c6ca3f9749b8c57c2e85b5b9f52514 ]
> 
> The issue is that the internal counter that triggers the watchdog reset
> is actually running at 4096 Hz instead of 1Hz, therefore the value
> given by userland (in sec) needs to be multiplied by 4096 to get the
> correct behavior.
[...]

The wdt_margin module parameter has the same problem.

Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.

Re: [PATCH 4.4 70/97] rtc: ds1374: wdt: Fix issue with timeout scaling from secs to wdt ticks

[Ben Hutchings]

On Fri, 2018-03-23 at 10:54 +0100, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> --
> 
> From: Moritz Fischer 
> 
> 
> [ Upstream commit 453d0744f6c6ca3f9749b8c57c2e85b5b9f52514 ]
> 
> The issue is that the internal counter that triggers the watchdog reset
> is actually running at 4096 Hz instead of 1Hz, therefore the value
> given by userland (in sec) needs to be multiplied by 4096 to get the
> correct behavior.
[...]

The wdt_margin module parameter has the same problem.

Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.

[PATCH 4.4 70/97] rtc: ds1374: wdt: Fix issue with timeout scaling from secs to wdt ticks

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Moritz Fischer 


[ Upstream commit 453d0744f6c6ca3f9749b8c57c2e85b5b9f52514 ]

The issue is that the internal counter that triggers the watchdog reset
is actually running at 4096 Hz instead of 1Hz, therefore the value
given by userland (in sec) needs to be multiplied by 4096 to get the
correct behavior.

Fixes: 920f91e50c5b ("drivers/rtc/rtc-ds1374.c: add watchdog support")
Signed-off-by: Moritz Fischer 
Signed-off-by: Alexandre Belloni 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/rtc/rtc-ds1374.c |7 ++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/rtc/rtc-ds1374.c
+++ b/drivers/rtc/rtc-ds1374.c
@@ -527,6 +527,10 @@ static long ds1374_wdt_ioctl(struct file
if (get_user(new_margin, (int __user *)arg))
return -EFAULT;
 
+   /* the hardware's tick rate is 4096 Hz, so
+* the counter value needs to be scaled accordingly
+*/
+   new_margin <<= 12;
if (new_margin < 1 || new_margin > 16777216)
return -EINVAL;
 
@@ -535,7 +539,8 @@ static long ds1374_wdt_ioctl(struct file
ds1374_wdt_ping();
/* fallthrough */
case WDIOC_GETTIMEOUT:
-   return put_user(wdt_margin, (int __user *)arg);
+   /* when returning ... inverse is true */
+   return put_user((wdt_margin >> 12), (int __user *)arg);
case WDIOC_SETOPTIONS:
if (copy_from_user(, (int __user *)arg, sizeof(int)))
return -EFAULT;

[PATCH 4.4 70/97] rtc: ds1374: wdt: Fix issue with timeout scaling from secs to wdt ticks

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Moritz Fischer 


[ Upstream commit 453d0744f6c6ca3f9749b8c57c2e85b5b9f52514 ]

The issue is that the internal counter that triggers the watchdog reset
is actually running at 4096 Hz instead of 1Hz, therefore the value
given by userland (in sec) needs to be multiplied by 4096 to get the
correct behavior.

Fixes: 920f91e50c5b ("drivers/rtc/rtc-ds1374.c: add watchdog support")
Signed-off-by: Moritz Fischer 
Signed-off-by: Alexandre Belloni 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/rtc/rtc-ds1374.c |7 ++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/rtc/rtc-ds1374.c
+++ b/drivers/rtc/rtc-ds1374.c
@@ -527,6 +527,10 @@ static long ds1374_wdt_ioctl(struct file
if (get_user(new_margin, (int __user *)arg))
return -EFAULT;
 
+   /* the hardware's tick rate is 4096 Hz, so
+* the counter value needs to be scaled accordingly
+*/
+   new_margin <<= 12;
if (new_margin < 1 || new_margin > 16777216)
return -EINVAL;
 
@@ -535,7 +539,8 @@ static long ds1374_wdt_ioctl(struct file
ds1374_wdt_ping();
/* fallthrough */
case WDIOC_GETTIMEOUT:
-   return put_user(wdt_margin, (int __user *)arg);
+   /* when returning ... inverse is true */
+   return put_user((wdt_margin >> 12), (int __user *)arg);
case WDIOC_SETOPTIONS:
if (copy_from_user(, (int __user *)arg, sizeof(int)))
return -EFAULT;