| Message ID | 20241126073646.126752-1-alexander.sverdlin@siemens.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | watchdog: rti: Fix off-by-one in heartbeat recovery | expand |
On 11/25/24 23:36, A. Sverdlin wrote: > From: Alexander Sverdlin <alexander.sverdlin@siemens.com> > > According to AM62x TRM WDT period is (RTIDWDPRLD + 1) * (2^13) / RTICLK1, > Fix the heartbeat recovery. In practice this doesn't affect rounded > heatbeat in seconds, but it does correct 4% of error in milliseconds, > for, say, default 60s heartbeat. This affects last_ping calculation. > > Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > drivers/watchdog/rti_wdt.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c > index 563d842014dfb..0416e54b17edb 100644 > --- a/drivers/watchdog/rti_wdt.c > +++ b/drivers/watchdog/rti_wdt.c > @@ -273,7 +273,8 @@ static int rti_wdt_probe(struct platform_device *pdev) > > set_bit(WDOG_HW_RUNNING, &wdd->status); > time_left_ms = rti_wdt_get_timeleft_ms(wdd); > - heartbeat_ms = readl(wdt->base + RTIDWDPRLD); > + /* AM62x TRM: texp = (RTIDWDPRLD + 1) * (2^13) / RTICLK1 */ > + heartbeat_ms = readl(wdt->base + RTIDWDPRLD) + 1; > heartbeat_ms <<= WDT_PRELOAD_SHIFT; > heartbeat_ms *= 1000; > do_div(heartbeat_ms, wdt->freq);
diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c index 563d842014dfb..0416e54b17edb 100644 --- a/drivers/watchdog/rti_wdt.c +++ b/drivers/watchdog/rti_wdt.c @@ -273,7 +273,8 @@ static int rti_wdt_probe(struct platform_device *pdev) set_bit(WDOG_HW_RUNNING, &wdd->status); time_left_ms = rti_wdt_get_timeleft_ms(wdd); - heartbeat_ms = readl(wdt->base + RTIDWDPRLD); + /* AM62x TRM: texp = (RTIDWDPRLD + 1) * (2^13) / RTICLK1 */ + heartbeat_ms = readl(wdt->base + RTIDWDPRLD) + 1; heartbeat_ms <<= WDT_PRELOAD_SHIFT; heartbeat_ms *= 1000; do_div(heartbeat_ms, wdt->freq);