watchdog: iTCO_wdt: Set NO_REBOOT if the watchdog is not already running

commit ef9b7bf52c2f47f0a9bf988543c577b92c92d15e upstream.

Daniel reported that the commit 1ae3e78c0820 ("watchdog: iTCO_wdt: No
need to stop the timer in probe") makes QEMU implementation of the iTCO
watchdog not to trigger reboot anymore when NO_REBOOT flag is initially
cleared using this option (in QEMU command line):

  -global ICH9-LPC.noreboot=false

The problem with the commit is that it left the unconditional setting of
NO_REBOOT that is not cleared anymore when the kernel keeps pinging the
watchdog (as opposed to the previous code that called iTCO_wdt_stop()
that cleared it).

Fix this so that we only set NO_REBOOT if the watchdog was not initially
running.

Fixes: 1ae3e78c0820 ("watchdog: iTCO_wdt: No need to stop the timer in probe")
Reported-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20221028062750.45451-1-mika.westerberg@linux.intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index 930798bac582df5aa133a893115abcb29ba3faf5..5ec52032117a7cf093bae7ca305293b30e6a5559 100644 (file)
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -401,14 +401,18 @@ static unsigned int iTCO_wdt_get_timeleft(struct watchdog_device *wd_dev)
        return time_left;
 }
 
-static void iTCO_wdt_set_running(struct iTCO_wdt_private *p)
+/* Returns true if the watchdog was running */
+static bool iTCO_wdt_set_running(struct iTCO_wdt_private *p)
 {
        u16 val;
 
-       /* Bit 11: TCO Timer Halt -> 0 = The TCO timer is * enabled */
+       /* Bit 11: TCO Timer Halt -> 0 = The TCO timer is enabled */
        val = inw(TCO1_CNT(p));
-       if (!(val & BIT(11)))
+       if (!(val & BIT(11))) {
                set_bit(WDOG_HW_RUNNING, &p->wddev.status);
+               return true;
+       }
+       return false;
 }
 
 /*
@@ -486,9 +490,6 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
                return -ENODEV; /* Cannot reset NO_REBOOT bit */
        }
 
-       /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
-       p->update_no_reboot_bit(p->no_reboot_priv, true);
-
        /* The TCO logic uses the TCO_EN bit in the SMI_EN register */
        if (!devm_request_region(dev, p->smi_res->start,
                                 resource_size(p->smi_res),
@@ -547,7 +548,13 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
        watchdog_set_drvdata(&p->wddev, p);
        platform_set_drvdata(pdev, p);
 
-       iTCO_wdt_set_running(p);
+       if (!iTCO_wdt_set_running(p)) {
+               /*
+                * If the watchdog was not running set NO_REBOOT now to
+                * prevent later reboots.
+                */
+               p->update_no_reboot_bit(p->no_reboot_priv, true);
+       }
 
        /* Check that the heartbeat value is within it's range;
           if not reset to the default */