From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933809AbdDELlu (ORCPT ); Wed, 5 Apr 2017 07:41:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60044 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932129AbdDELlS (ORCPT ); Wed, 5 Apr 2017 07:41:18 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 4568C80F7B Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=pbonzini@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 4568C80F7B From: Paolo Bonzini To: linux-kernel@vger.kernel.org Cc: Andy Shevchenko , Wim Van Sebroeck , Guenter Roeck , linux-watchdog@vger.kernel.org Subject: [PATCH v2] iTCO_wdt: all versions count down twice Date: Wed, 5 Apr 2017 13:41:15 +0200 Message-Id: <20170405114115.17475-1-pbonzini@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 05 Apr 2017 11:41:18 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Cc: Wim Van Sebroeck Cc: Guenter Roeck Cc: linux-watchdog@vger.kernel.org Reviewed-by: Andy Shevchenko Signed-off-by: Paolo Bonzini --- Documentation/watchdog/watchdog-parameters.txt | 2 +- drivers/watchdog/iTCO_wdt.c | 22 ++++++++++------------ 2 files changed, 11 insertions(+), 13 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. - (2smi_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" */ @@ -359,6 +355,8 @@ 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); -- 2.9.3