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

Judith Mendez posted 1 patch 1 year, 10 months ago
There is a newer version of this series
drivers/watchdog/rti_wdt.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
[PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin
Posted by Judith Mendez 1 year, 10 months ago 
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 <jm@ti.com>
---
 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
Re: [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin
Posted by Guenter Roeck 1 year, 10 months ago 
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 <jm@ti.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  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
> 
>
Re: [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin
Posted by Rafael Beims 1 year, 10 months ago 
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 <jm@ti.com>
> ---
>   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 <rafael.beims@toradex.com>


Rafael
Re: [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin
Posted by Francesco Dolcini 1 year, 10 months ago 
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
Re: [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin
Posted by Judith Mendez 1 year, 10 months ago 
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
>

Patchew 2.1-devel-b67e4c2

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