On Wed, Apr 5, 2017 at 12:03 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> The ICH9 is listed as having TCO v2, and indeed the behavior in the
> datasheet corresponds to v2 (for example the NO_REBOOT flag is
> accessible via the 16KiB-aligned Root Complex Base Address).
>
> However, the TCO counts twice just like in v1; the documentation
> of the SECOND_TO_STS bit says: "ICH9 sets this bit to 1 to indicate
> that the TIMEOUT bit had been (or is currently) set and a second
> timeout occurred before the TCO_RLD register was written. If this
> bit is set and the NO_REBOOT config bit is 0, then the ICH9 will
> reboot the system after the second timeout. The same can be found
> in the BayTrail (Atom E3800) datasheet, and even HOWTOs around
> the Internet say that it will reboot after _twice_ the specified
> heartbeat.
>
> I did not find the Apollo Lake datasheet, but because v4/v5 has
> a SECOND_TO_STS bit just like the previous version I'm enabling
> this for Apollo Lake as well.
Regarding to last proposed changes Apollo Lake has some register offset issue.
Nevertheless, this patch AFAIU still applies.
One nit below.
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
>
> Cc: Wim Van Sebroeck <wim@xxxxxxxxx>
> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> Cc: linux-watchdog@xxxxxxxxxxxxxxx
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> Documentation/watchdog/watchdog-parameters.txt | 2 +-
> drivers/watchdog/iTCO_wdt.c | 23 ++++++++++-------------
> 2 files changed, 11 insertions(+), 14 deletions(-)
>
> diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt
> index 4f7d86dd0a5d..914518aeb972 100644
> --- a/Documentation/watchdog/watchdog-parameters.txt
> +++ b/Documentation/watchdog/watchdog-parameters.txt
> @@ -117,7 +117,7 @@ nowayout: Watchdog cannot be stopped once started
> -------------------------------------------------
> iTCO_wdt:
> heartbeat: Watchdog heartbeat in seconds.
> - (2<heartbeat<39 (TCO v1) or 613 (TCO v2), default=30)
> + (5<=heartbeat<=74 (TCO v1) or 1226 (TCO v2), default=30)
> nowayout: Watchdog cannot be stopped once started
> (default=kernel config parameter)
> -------------------------------------------------
> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
> index 3d0abc0d59b4..c9230a0cdc83 100644
> --- a/drivers/watchdog/iTCO_wdt.c
> +++ b/drivers/watchdog/iTCO_wdt.c
> @@ -280,16 +280,15 @@ static int iTCO_wdt_ping(struct watchdog_device *wd_dev)
>
> iTCO_vendor_pre_keepalive(p->smi_res, wd_dev->timeout);
>
> + /* Reset the timeout status bit so that the timer
> + * needs to count down twice again before rebooting */
> + outw(0x0008, TCO1_STS(p)); /* write 1 to clear bit */
> +
> /* Reload the timer by writing to the TCO Timer Counter register */
> - if (p->iTCO_version >= 2) {
> + if (p->iTCO_version >= 2)
> outw(0x01, TCO_RLD(p));
> - } else if (p->iTCO_version == 1) {
> - /* Reset the timeout status bit so that the timer
> - * needs to count down twice again before rebooting */
> - outw(0x0008, TCO1_STS(p)); /* write 1 to clear bit */
> -
> + else if (p->iTCO_version == 1)
> outb(0x01, TCO_RLD(p));
> - }
>
> spin_unlock(&p->io_lock);
> return 0;
> @@ -302,11 +301,8 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
> unsigned char val8;
> unsigned int tmrval;
>
> - tmrval = seconds_to_ticks(p, t);
> -
> - /* For TCO v1 the timer counts down twice before rebooting */
> - if (p->iTCO_version == 1)
> - tmrval /= 2;
> + /* The timer counts down twice before rebooting */
> + tmrval = seconds_to_ticks(p, t) / 2;
>
> /* from the specs: */
> /* "Values of 0h-3h are ignored and should not be attempted" */
> @@ -359,8 +355,9 @@ static unsigned int iTCO_wdt_get_timeleft(struct watchdog_device *wd_dev)
> spin_lock(&p->io_lock);
> val16 = inw(TCO_RLD(p));
> val16 &= 0x3ff;
> + if (!(inw(TCO1_STS(p)) & 0x0008))
> + val16 += (inw(TCOv2_TMR(p)) & 0x3ff);
> spin_unlock(&p->io_lock);
> -
> time_left = ticks_to_seconds(p, val16);
This change does not belong to the patch.
> } else if (p->iTCO_version == 1) {
> spin_lock(&p->io_lock);
> --
> 2.9.3
>
--
With Best Regards,
Andy Shevchenko
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