On 30.05.21 15:19, Guenter Roeck wrote: > On Sun, May 30, 2021 at 01:24:23PM +0200, Jan Kiszka wrote: >> From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> >> >> This was already attempted to fix via 1fccb73011ea: If the BIOS did not >> enable TCO SMIs, the timer definitely needs to trigger twice in order to >> cause a reboot. If TCO SMIs are on, as well as SMIs in general, we can >> continue to assume that the BIOS will perform a reboot on the first >> timeout. >> >> QEMU with its ICH9 and related BIOS falls into the former category, >> currently taking twice the configured timeout in order to reboot the >> machine. For iTCO version that fall under turn_SMI_watchdog_clear_off, >> this is also true and was currently only addressed for v1, irrespective >> of the turn_SMI_watchdog_clear_off value. >> >> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> >> --- >> >> Changes in v2: >> - consider GBL_SMI_EN as well >> >> drivers/watchdog/iTCO_wdt.c | 12 +++++++++--- >> 1 file changed, 9 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c >> index bf31d7b67a69..3f1324871cfd 100644 >> --- a/drivers/watchdog/iTCO_wdt.c >> +++ b/drivers/watchdog/iTCO_wdt.c >> @@ -71,6 +71,8 @@ >> #define TCOBASE(p) ((p)->tco_res->start) >> /* SMI Control and Enable Register */ >> #define SMI_EN(p) ((p)->smi_res->start) >> +#define TCO_EN (1 << 13) >> +#define GBL_SMI_EN (1 << 0) >> >> #define TCO_RLD(p) (TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */ >> #define TCOv1_TMR(p) (TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/ >> @@ -355,8 +357,12 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t) >> >> tmrval = seconds_to_ticks(p, t); >> >> - /* For TCO v1 the timer counts down twice before rebooting */ >> - if (p->iTCO_version == 1) >> + /* >> + * If TCO SMIs are off, the timer counts down twice before rebooting. >> + * Otherwise, the BIOS generally reboots when the SMI triggers. >> + */ >> + if (p->smi_res && >> + (SMI_EN(p) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN)) >> tmrval /= 2; > > This expands the scope of this adjustment to all versions, while at the same > time making it conditional for v1. Is this correct ? What for systems with v1 > TCO where the above conditions are not met ? Yes, this is intended. You find the reference to "reboots on second timeout" even in latest EHL datasheets (v6). Jan > > Guenter > >> >> /* from the specs: */ >> @@ -521,7 +527,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev) >> * Disables TCO logic generating an SMI# >> */ >> val32 = inl(SMI_EN(p)); >> - val32 &= 0xffffdfff; /* Turn off SMI clearing watchdog */ >> + val32 &= ~TCO_EN; /* Turn off SMI clearing watchdog */ >> outl(val32, SMI_EN(p)); >> } >> >> -- >> 2.26.2 -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux
