From: Judith Mendez <jm@ti.com>
To: Wim Van Sebroeck <wim@linux-watchdog.org>,
Guenter Roeck <linux@roeck-us.net>,
<linux-watchdog@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin
Date: Wed, 3 Apr 2024 16:24:26 -0500 [thread overview]
Message-ID: <20240403212426.582727-1-jm@ti.com> (raw)
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
next reply other threads:[~2024-04-03 21:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-03 21:24 Judith Mendez [this message]
2024-04-04 8:28 ` [PATCH] watchdog: rti_wdt: Set min_hw_heartbeat_ms to accommodate 5% safety margin Francesco Dolcini
2024-04-04 15:32 ` Judith Mendez
2024-04-05 12:37 ` Rafael Beims
2024-04-06 12:56 ` Guenter Roeck
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