From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F040CC433F5 for ; Fri, 8 Oct 2021 07:52:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7B0961029 for ; Fri, 8 Oct 2021 07:52:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232968AbhJHHyl (ORCPT ); Fri, 8 Oct 2021 03:54:41 -0400 Received: from gecko.sbs.de ([194.138.37.40]:38253 "EHLO gecko.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229868AbhJHHyg (ORCPT ); Fri, 8 Oct 2021 03:54:36 -0400 Received: from mail2.sbs.de (mail2.sbs.de [192.129.41.66]) by gecko.sbs.de (8.15.2/8.15.2) with ESMTPS id 1987qLus026454 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 8 Oct 2021 09:52:21 +0200 Received: from [167.87.4.198] ([167.87.4.198]) by mail2.sbs.de (8.15.2/8.15.2) with ESMTP id 1987qKUg002516; Fri, 8 Oct 2021 09:52:20 +0200 Subject: Re: [PATCH] Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout" To: Guenter Roeck , Wim Van Sebroeck Cc: linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?Q?Mantas_Mikul=c4=97nas?= , "Javier S . Pedro" References: <20211008003302.1461733-1-linux@roeck-us.net> From: Jan Kiszka Message-ID: <9b9c797c-04f1-0ccf-b6fe-e9f1e4f5c17d@siemens.com> Date: Fri, 8 Oct 2021 09:52:20 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20211008003302.1461733-1-linux@roeck-us.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org On 08.10.21 02:33, Guenter Roeck wrote: > This reverts commit cb011044e34c ("watchdog: iTCO_wdt: Account for > rebooting on second timeout") and commit aec42642d91f ("watchdog: iTCO_wdt: > Fix detection of SMI-off case") since those patches cause a regression > on certain boards (https://bugzilla.kernel.org/show_bug.cgi?id=213809). > > While this revert may result in some boards to only reset after twice > the configured timeout value, that is still better than a watchdog reset > after half the configured value. > > Fixes: cb011044e34c ("watchdog: iTCO_wdt: Account for rebooting on second timeout") > Fixes: aec42642d91f ("watchdog: iTCO_wdt: Fix detection of SMI-off case") > Cc: Jan Kiszka > Cc: Mantas Mikulėnas > Reported-by: Javier S. Pedro > Signed-off-by: Guenter Roeck > --- > drivers/watchdog/iTCO_wdt.c | 12 +++--------- > 1 file changed, 3 insertions(+), 9 deletions(-) > > diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c > index 643c6c2d0b72..ced2fc0deb8c 100644 > --- a/drivers/watchdog/iTCO_wdt.c > +++ b/drivers/watchdog/iTCO_wdt.c > @@ -71,8 +71,6 @@ > #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*/ > @@ -357,12 +355,8 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t) > > tmrval = seconds_to_ticks(p, t); > > - /* > - * 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 && > - (inl(SMI_EN(p)) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN)) > + /* For TCO v1 the timer counts down twice before rebooting */ > + if (p->iTCO_version == 1) > tmrval /= 2; > > /* from the specs: */ > @@ -527,7 +521,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev) > * Disables TCO logic generating an SMI# > */ > val32 = inl(SMI_EN(p)); > - val32 &= ~TCO_EN; /* Turn off SMI clearing watchdog */ > + val32 &= 0xffffdfff; /* Turn off SMI clearing watchdog */ > outl(val32, SMI_EN(p)); > } > > Sigh, how broken is this architecture of the iTCO? Agreed, this leaves no option then. BTW, the fact that we saw an inconsistency in read-back timeout indicates that there is still an issue for the remaining /= 2 case (means v1), but I'm loosing interest in fixing those issues, given how hard it is to test broadly without breaking users first. Jan -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux