| Message ID | 6a4b54ac-9588-e172-c4c7-b91d524a851e@siemens.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | watchdog: rti_wdt: Fix calculation and evaluation of preset heartbeat | expand |
On Mon, Feb 21, 2022 at 05:22:38PM +0100, Jan Kiszka wrote: > From: Jan Kiszka <jan.kiszka@siemens.com> > > This ensures that the same value is read back as was eventually > programmed when using seconds as accuracy. Even then, comparing the more > precise heartbeat_ms against heartbeat in seconds will almost never > provide a match and will needlessly raise a warning. Fix by comparing > apples to apples. > > Tested in combination with U-Boot as watchdog starter. > > Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > > To fully work, it also needs a U-Boot patch to add the same 10% margin > to the clock frequency: > > https://patchwork.ozlabs.org/project/uboot/patch/9b3603a3-1bf4-eb57-c378-20d5c2accc34@siemens.com/ > > drivers/watchdog/rti_wdt.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c > index 117bc2a8eb0a..3ecd14e180fb 100644 > --- a/drivers/watchdog/rti_wdt.c > +++ b/drivers/watchdog/rti_wdt.c > @@ -252,6 +252,7 @@ static int rti_wdt_probe(struct platform_device *pdev) > } > > if (readl(wdt->base + RTIDWDCTRL) == WDENABLE_KEY) { > + int preset_heartbeat; > u32 time_left_ms; > u64 heartbeat_ms; > u32 wsize; > @@ -262,11 +263,12 @@ static int rti_wdt_probe(struct platform_device *pdev) > heartbeat_ms <<= WDT_PRELOAD_SHIFT; > heartbeat_ms *= 1000; > do_div(heartbeat_ms, wdt->freq); > - if (heartbeat_ms != heartbeat * 1000) > + preset_heartbeat = heartbeat_ms + 500; > + preset_heartbeat /= 1000; > + if (preset_heartbeat != heartbeat) > dev_warn(dev, "watchdog already running, ignoring heartbeat config!\n"); > > - heartbeat = heartbeat_ms; > - heartbeat /= 1000; > + heartbeat = preset_heartbeat; > > wsize = readl(wdt->base + RTIWWDSIZECTRL); > ret = rti_wdt_setup_hw_hb(wdd, wsize);
diff --git a/drivers/watchdog/rti_wdt.c b/drivers/watchdog/rti_wdt.c index 117bc2a8eb0a..3ecd14e180fb 100644 --- a/drivers/watchdog/rti_wdt.c +++ b/drivers/watchdog/rti_wdt.c @@ -252,6 +252,7 @@ static int rti_wdt_probe(struct platform_device *pdev) } if (readl(wdt->base + RTIDWDCTRL) == WDENABLE_KEY) { + int preset_heartbeat; u32 time_left_ms; u64 heartbeat_ms; u32 wsize; @@ -262,11 +263,12 @@ static int rti_wdt_probe(struct platform_device *pdev) heartbeat_ms <<= WDT_PRELOAD_SHIFT; heartbeat_ms *= 1000; do_div(heartbeat_ms, wdt->freq); - if (heartbeat_ms != heartbeat * 1000) + preset_heartbeat = heartbeat_ms + 500; + preset_heartbeat /= 1000; + if (preset_heartbeat != heartbeat) dev_warn(dev, "watchdog already running, ignoring heartbeat config!\n"); - heartbeat = heartbeat_ms; - heartbeat /= 1000; + heartbeat = preset_heartbeat; wsize = readl(wdt->base + RTIWWDSIZECTRL); ret = rti_wdt_setup_hw_hb(wdd, wsize);