| Message ID | 20200611191750.28096-5-a.fatoum@pengutronix.de (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | watchdog: f71808e_wdt: migrate to kernel | expand |
On Thu, Jun 11, 2020 at 09:17:45PM +0200, Ahmad Fatoum wrote: > The flag indicating a watchdog timeout having occurred normally persists > till Power-On Reset of the Fintek Super I/O chip. The user can clear it > by writing a `1' to the bit. > > The driver doesn't offer a restart method, so regular system reboot > might not reset the Super I/O and if the watchdog isn't enabled, we > won't touch the register containing the bit on the next boot. > In this case all subsequent regular reboots will be wrongly flagged > by the driver as being caused by the watchdog. > > Fix this by having the flag cleared after read. This is also done by > other drivers like those for the i6300esb and mpc8xxx_wdt. > > Fixes: b97cb21a4634 ("watchdog: f71808e_wdt: Fix WDTMOUT_STS register read") > Cc: stable@vger.kernel.org > Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > drivers/watchdog/f71808e_wdt.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c > index 8e5584c54423..26bf366aebc2 100644 > --- a/drivers/watchdog/f71808e_wdt.c > +++ b/drivers/watchdog/f71808e_wdt.c > @@ -706,6 +706,13 @@ static int __init watchdog_init(int sioaddr) > wdt_conf = superio_inb(sioaddr, F71808FG_REG_WDT_CONF); > watchdog.caused_reboot = wdt_conf & BIT(F71808FG_FLAG_WDTMOUT_STS); > > + /* > + * We don't want WDTMOUT_STS to stick around till regular reboot. > + * Write 1 to the bit to clear it to zero. > + */ > + superio_outb(sioaddr, F71808FG_REG_WDT_CONF, > + wdt_conf | BIT(F71808FG_FLAG_WDTMOUT_STS)); > + > superio_exit(sioaddr); > > err = watchdog_set_timeout(timeout);
diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c index 8e5584c54423..26bf366aebc2 100644 --- a/drivers/watchdog/f71808e_wdt.c +++ b/drivers/watchdog/f71808e_wdt.c @@ -706,6 +706,13 @@ static int __init watchdog_init(int sioaddr) wdt_conf = superio_inb(sioaddr, F71808FG_REG_WDT_CONF); watchdog.caused_reboot = wdt_conf & BIT(F71808FG_FLAG_WDTMOUT_STS); + /* + * We don't want WDTMOUT_STS to stick around till regular reboot. + * Write 1 to the bit to clear it to zero. + */ + superio_outb(sioaddr, F71808FG_REG_WDT_CONF, + wdt_conf | BIT(F71808FG_FLAG_WDTMOUT_STS)); + superio_exit(sioaddr); err = watchdog_set_timeout(timeout);
The flag indicating a watchdog timeout having occurred normally persists till Power-On Reset of the Fintek Super I/O chip. The user can clear it by writing a `1' to the bit. The driver doesn't offer a restart method, so regular system reboot might not reset the Super I/O and if the watchdog isn't enabled, we won't touch the register containing the bit on the next boot. In this case all subsequent regular reboots will be wrongly flagged by the driver as being caused by the watchdog. Fix this by having the flag cleared after read. This is also done by other drivers like those for the i6300esb and mpc8xxx_wdt. Fixes: b97cb21a4634 ("watchdog: f71808e_wdt: Fix WDTMOUT_STS register read") Cc: stable@vger.kernel.org Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> --- drivers/watchdog/f71808e_wdt.c | 7 +++++++ 1 file changed, 7 insertions(+)