2024-04-03 21:24:49

by Judith Mendez

Subject: [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin

On AM62x, the watchdog is pet before the valid window
is open. Fix min_hw_heartbeat and accommodate a 5% safety
margin with the exception of open window size < 10%,
which shall use <5% due to the smaller open window size.

Signed-off-by: Judith Mendez <[email protected]>
---
drivers/watchdog/rti_wdt.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
index 8e1be7ba0103..0b16ada659cc 100644
--- a/drivers/watchdog/rti_wdt.c
+++ b/drivers/watchdog/rti_wdt.c
@@ -92,7 +92,7 @@ static int rti_wdt_start(struct watchdog_device *wdd)
* to be 50% or less than that; we obviouly want to configure the open
* window as large as possible so we select the 50% option.
*/
- wdd->min_hw_heartbeat_ms = 500 * wdd->timeout;
+ wdd->min_hw_heartbeat_ms = 550 * wdd->timeout;

/* Generate NMI when wdt expires */
writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
@@ -126,31 +126,33 @@ static int rti_wdt_setup_hw_hb(struct watchdog_device *wdd, u32 wsize)
* be petted during the open window; not too early or not too late.
* The HW configuration options only allow for the open window size
* to be 50% or less than that.
+ * To avoid any glitches, we accommodate 5% safety margin, with the
+ * exception of open window size < 10%.
*/
switch (wsize) {
case RTIWWDSIZE_50P:
- /* 50% open window => 50% min heartbeat */
- wdd->min_hw_heartbeat_ms = 500 * heartbeat;
+ /* 50% open window => 55% min heartbeat */
+ wdd->min_hw_heartbeat_ms = 550 * heartbeat;
break;

case RTIWWDSIZE_25P:
- /* 25% open window => 75% min heartbeat */
- wdd->min_hw_heartbeat_ms = 750 * heartbeat;
+ /* 25% open window => 80% min heartbeat */
+ wdd->min_hw_heartbeat_ms = 800 * heartbeat;
break;

case RTIWWDSIZE_12P5:
- /* 12.5% open window => 87.5% min heartbeat */
- wdd->min_hw_heartbeat_ms = 875 * heartbeat;
+ /* 12.5% open window => 92.5% min heartbeat */
+ wdd->min_hw_heartbeat_ms = 925 * heartbeat;
break;

case RTIWWDSIZE_6P25:
- /* 6.5% open window => 93.5% min heartbeat */
- wdd->min_hw_heartbeat_ms = 935 * heartbeat;
+ /* 6.5% open window => 96.5% min heartbeat */
+ wdd->min_hw_heartbeat_ms = 965 * heartbeat;
break;

case RTIWWDSIZE_3P125:
- /* 3.125% open window => 96.9% min heartbeat */
- wdd->min_hw_heartbeat_ms = 969 * heartbeat;
+ /* 3.125% open window => 97.9% min heartbeat */
+ wdd->min_hw_heartbeat_ms = 979 * heartbeat;
break;

default:
--
2.43.2

2024-04-04 08:28:38

by Francesco Dolcini

Subject: Re: [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin

Hello Judith,

On Wed, Apr 03, 2024 at 04:24:26PM -0500, Judith Mendez wrote:
> On AM62x, the watchdog is pet before the valid window
> is open. Fix min_hw_heartbeat and accommodate a 5% safety

Fix => Add Fixes tag + Cc:stable ?

Thanks,
Francesco

2024-04-04 15:33:53

by Judith Mendez

Subject: Re: [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin

Hi Francesco,

On 4/4/24 3:28 AM, Francesco Dolcini wrote:
> Hello Judith,
>
> On Wed, Apr 03, 2024 at 04:24:26PM -0500, Judith Mendez wrote:
>> On AM62x, the watchdog is pet before the valid window
>> is open. Fix min_hw_heartbeat and accommodate a 5% safety
>
> Fix => Add Fixes tag + Cc:stable ?

Thanks will add for v2
~ Judith

>
> Thanks,
> Francesco
>

2024-04-05 12:40:40

by Rafael Beims

Subject: Re: [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin

On 03/04/2024 18:24, Judith Mendez wrote:
> On AM62x, the watchdog is pet before the valid window
> is open. Fix min_hw_heartbeat and accommodate a 5% safety
> margin with the exception of open window size < 10%,
> which shall use <5% due to the smaller open window size.
>
> Signed-off-by: Judith Mendez <[email protected]>
> ---
> drivers/watchdog/rti_wdt.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
> index 8e1be7ba0103..0b16ada659cc 100644
> --- a/drivers/watchdog/rti_wdt.c
> +++ b/drivers/watchdog/rti_wdt.c
> @@ -92,7 +92,7 @@ static int rti_wdt_start(struct watchdog_device *wdd)
> * to be 50% or less than that; we obviouly want to configure the open
> * window as large as possible so we select the 50% option.
> */
> - wdd->min_hw_heartbeat_ms = 500 * wdd->timeout;
> + wdd->min_hw_heartbeat_ms = 550 * wdd->timeout;
>
> /* Generate NMI when wdt expires */
> writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
> @@ -126,31 +126,33 @@ static int rti_wdt_setup_hw_hb(struct watchdog_device *wdd, u32 wsize)
> * be petted during the open window; not too early or not too late.
> * The HW configuration options only allow for the open window size
> * to be 50% or less than that.
> + * To avoid any glitches, we accommodate 5% safety margin, with the
> + * exception of open window size < 10%.
> */
> switch (wsize) {
> case RTIWWDSIZE_50P:
> - /* 50% open window => 50% min heartbeat */
> - wdd->min_hw_heartbeat_ms = 500 * heartbeat;
> + /* 50% open window => 55% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 550 * heartbeat;
> break;
>
> case RTIWWDSIZE_25P:
> - /* 25% open window => 75% min heartbeat */
> - wdd->min_hw_heartbeat_ms = 750 * heartbeat;
> + /* 25% open window => 80% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 800 * heartbeat;
> break;
>
> case RTIWWDSIZE_12P5:
> - /* 12.5% open window => 87.5% min heartbeat */
> - wdd->min_hw_heartbeat_ms = 875 * heartbeat;
> + /* 12.5% open window => 92.5% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 925 * heartbeat;
> break;
>
> case RTIWWDSIZE_6P25:
> - /* 6.5% open window => 93.5% min heartbeat */
> - wdd->min_hw_heartbeat_ms = 935 * heartbeat;
> + /* 6.5% open window => 96.5% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 965 * heartbeat;
> break;
>
> case RTIWWDSIZE_3P125:
> - /* 3.125% open window => 96.9% min heartbeat */
> - wdd->min_hw_heartbeat_ms = 969 * heartbeat;
> + /* 3.125% open window => 97.9% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 979 * heartbeat;
> break;
>
> default:


I tested this patch by enabling the systemd watchdog adding
RuntimeWatchdogSec=30 to system.conf on a Verdin AM62.

This setup causes watchdog resets without the patch, and with the patch
applied I didn't see any watchdog related reboots.


Tested-by: Rafael Beims <[email protected]>


Rafael

2024-04-06 12:56:41

by Guenter Roeck

Subject: Re: [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin

On Wed, Apr 03, 2024 at 04:24:26PM -0500, Judith Mendez wrote:
> On AM62x, the watchdog is pet before the valid window
> is open. Fix min_hw_heartbeat and accommodate a 5% safety
> margin with the exception of open window size < 10%,
> which shall use <5% due to the smaller open window size.
>
> Signed-off-by: Judith Mendez <[email protected]>

Reviewed-by: Guenter Roeck <[email protected]>

> ---
> drivers/watchdog/rti_wdt.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c
> index 8e1be7ba0103..0b16ada659cc 100644
> --- a/drivers/watchdog/rti_wdt.c
> +++ b/drivers/watchdog/rti_wdt.c
> @@ -92,7 +92,7 @@ static int rti_wdt_start(struct watchdog_device *wdd)
> * to be 50% or less than that; we obviouly want to configure the open
> * window as large as possible so we select the 50% option.
> */
> - wdd->min_hw_heartbeat_ms = 500 * wdd->timeout;
> + wdd->min_hw_heartbeat_ms = 550 * wdd->timeout;
>
> /* Generate NMI when wdt expires */
> writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
> @@ -126,31 +126,33 @@ static int rti_wdt_setup_hw_hb(struct watchdog_device *wdd, u32 wsize)
> * be petted during the open window; not too early or not too late.
> * The HW configuration options only allow for the open window size
> * to be 50% or less than that.
> + * To avoid any glitches, we accommodate 5% safety margin, with the
> + * exception of open window size < 10%.
> */
> switch (wsize) {
> case RTIWWDSIZE_50P:
> - /* 50% open window => 50% min heartbeat */
> - wdd->min_hw_heartbeat_ms = 500 * heartbeat;
> + /* 50% open window => 55% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 550 * heartbeat;
> break;
>
> case RTIWWDSIZE_25P:
> - /* 25% open window => 75% min heartbeat */
> - wdd->min_hw_heartbeat_ms = 750 * heartbeat;
> + /* 25% open window => 80% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 800 * heartbeat;
> break;
>
> case RTIWWDSIZE_12P5:
> - /* 12.5% open window => 87.5% min heartbeat */
> - wdd->min_hw_heartbeat_ms = 875 * heartbeat;
> + /* 12.5% open window => 92.5% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 925 * heartbeat;
> break;
>
> case RTIWWDSIZE_6P25:
> - /* 6.5% open window => 93.5% min heartbeat */
> - wdd->min_hw_heartbeat_ms = 935 * heartbeat;
> + /* 6.5% open window => 96.5% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 965 * heartbeat;
> break;
>
> case RTIWWDSIZE_3P125:
> - /* 3.125% open window => 96.9% min heartbeat */
> - wdd->min_hw_heartbeat_ms = 969 * heartbeat;
> + /* 3.125% open window => 97.9% min heartbeat */
> + wdd->min_hw_heartbeat_ms = 979 * heartbeat;
> break;
>
> default:
> --
> 2.43.2
>
>