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From: Chris Packham <judge.packham@gmail.com>
To: u-boot@lists.denx.de
Subject: [PATCH] watchdog: Handle timer wrap around
Date: Mon, 24 Feb 2020 13:20:33 +1300	[thread overview]
Message-ID: <20200224002033.17860-1-judge.packham@gmail.com> (raw)

On some platforms/architectures the value from get_timer() can wrap.
This is particularly problematic when long-running code needs to measure
a time difference as is the case with watchdog_reset() which tries to
avoid tickling the watchdog too frequently.

Use time_after() from time.h instead of a plain > comparison to avoid
any issues with the time wrapping on a system that has been sitting in
u-boot for a long time.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
---

 drivers/watchdog/wdt-uclass.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/wdt-uclass.c b/drivers/watchdog/wdt-uclass.c
index cf1c52747397..d9e4dc7cb8a4 100644
--- a/drivers/watchdog/wdt-uclass.c
+++ b/drivers/watchdog/wdt-uclass.c
@@ -7,6 +7,7 @@
 #include <dm.h>
 #include <errno.h>
 #include <hang.h>
+#include <time.h>
 #include <wdt.h>
 #include <dm/device-internal.h>
 #include <dm/lists.h>
@@ -83,7 +84,7 @@ void watchdog_reset(void)
 
 	/* Do not reset the watchdog too often */
 	now = get_timer(0);
-	if (now > next_reset) {
+	if (time_after(now, next_reset)) {
 		next_reset = now + 1000;	/* reset every 1000ms */
 		wdt_reset(gd->watchdog_dev);
 	}
-- 
2.25.1

             reply	other threads:[~2020-02-24  0:20 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24  0:20 Chris Packham [this message]
2020-02-24 11:48 ` [PATCH] watchdog: Handle timer wrap around Stefan Roese
2020-03-16 14:19 ` Stefan Roese

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