linux-kernel - [PATCH 4.13 1/2] watchdog: Revert "iTCO

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Date:   Thu, 12 Oct 2017 23:26:02 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Wim Van Sebroeck <wim@...ana.be>,
        Martin Wilck <mwilck@...e.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 4.13 1/2] watchdog: Revert "iTCO_wdt: all versions count down twice"

4.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Wim Van Sebroeck <wim@...ana.be>

commit fc61e83a29308601e6e8a0759e24fc8fe2122692 upstream.

This reverts commit 1fccb73011ea8a5fa0c6d357c33fa29c695139ea.
Reported as Bug 196509 - iTCO_wdt regression reboot before timeout expire

Signed-off-by: Wim Van Sebroeck <wim@...ana.be>
Cc: Martin Wilck <mwilck@...e.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 Documentation/watchdog/watchdog-parameters.txt |    2 +-
 drivers/watchdog/iTCO_wdt.c                    |   22 ++++++++++++----------
 2 files changed, 13 insertions(+), 11 deletions(-)

--- a/Documentation/watchdog/watchdog-parameters.txt
+++ b/Documentation/watchdog/watchdog-parameters.txt
@@ -117,7 +117,7 @@ nowayout: Watchdog cannot be stopped onc
 -------------------------------------------------
 iTCO_wdt:
 heartbeat: Watchdog heartbeat in seconds.
-	(5<=heartbeat<=74 (TCO v1) or 1226 (TCO v2), default=30)
+	(2<heartbeat<39 (TCO v1) or 613 (TCO v2), default=30)
 nowayout: Watchdog cannot be stopped once started
 	(default=kernel config parameter)
 -------------------------------------------------
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -306,15 +306,16 @@ static int iTCO_wdt_ping(struct watchdog
 
 	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)
+	} 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 */
+
 		outb(0x01, TCO_RLD(p));
+	}
 
 	spin_unlock(&p->io_lock);
 	return 0;
@@ -327,8 +328,11 @@ static int iTCO_wdt_set_timeout(struct w
 	unsigned char val8;
 	unsigned int tmrval;
 
-	/* The timer counts down twice before rebooting */
-	tmrval = seconds_to_ticks(p, t) / 2;
+	tmrval = seconds_to_ticks(p, t);
+
+	/* For TCO v1 the timer counts down twice before rebooting */
+	if (p->iTCO_version == 1)
+		tmrval /= 2;
 
 	/* from the specs: */
 	/* "Values of 0h-3h are ignored and should not be attempted" */
@@ -381,8 +385,6 @@ static unsigned int iTCO_wdt_get_timelef
 		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);