From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH] OMAP2PLUS: WDT: Fix: Disable WDT after reset during init Date: Fri, 01 Oct 2010 07:43:08 -0700 Message-ID: <8762xmdldv.fsf@deeprootsystems.com> References: <1285834270-32766-1-git-send-email-charu@ti.com> <4CA45341.3080300@ti.com> <87vd5njpyq.fsf@deeprootsystems.com> <4CA49ADE.6080202@ti.com> <20100930150713.GG3117@atomide.com> <87bp7ff962.fsf@deeprootsystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pv0-f174.google.com ([74.125.83.174]:34279 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756949Ab0JAOnT (ORCPT ); Fri, 1 Oct 2010 10:43:19 -0400 In-Reply-To: (Charulatha Varadarajan's message of "Fri, 1 Oct 2010 19:03:53 +0530") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Varadarajan, Charulatha" Cc: Tony Lindgren , "Cousson, Benoit" , "Shilimkar, Santosh" , "Menon, Nishanth" , "wim@iguana.be" , "linux-omap@vger.kernel.org" , "linux-watchdog@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "paul@pwsan.com" , "Nayak, Rajendra" , "Basak, Partha" "Varadarajan, Charulatha" writes: > Tony, Benoit, Kevin, > >> > >> > > >> > >> > > I think that disabling it should be done only if the >> > CONFIG_OMAP_WDT >> > >> > > is not set. >> > >> > >> > >> > How about disabling is done always unless CONFIG_WATCHDOG_NOWAYOUT >> > >> > is set? >> > >> >> > >> As given in the patch description, this patch does a disable of >> > watchdog >> > >> timer, during init, to avoid the system rebooting that happens due to >> > >> enabling of watchdog timer after a reset of the module (during hwmod >> > init). >> > >> >> > >> According to the default WDT registers values, the system reboot >> would >> > >> happen in ~10s if watchdog is enabled with default values. Hence, >> after >> > >> a WDT module reset during init, the watchdog has to be disabled >> within >> > 10s >> > >> otherwise the system will keep rebooting. >> > >> >> > >> Hence irrespective of CONFIG_WATCHDOG_NOWAYOUT/ CONFIG_OMAP_WDT, >> > >> the watchdog timer needs to be disabled after a WDT reset has >> happened. >> > >> >> > > One more option is to avoid the software reset using the >> CONFIG_OMAP_WDT >> > > flag. Something like below. >> > >> > This was already proposed by Charu, and rejected. >> > >> > Doing this means we have a dependency on particular bootloader init, and >> > we'd like to get rid of *all* assumptions about what the bootloader does >> > (or does not do.) >> > >> you mean is not depeding on bootloader to disable WDT. Make sense. >> > > Let me know your opinion on how to handle this issue. IMO, we should do what your original patch did: always disable the WDT, just like most/all bootloaders do. If we want to make changes later to support product needs (like no disable on boot, etc.) that is a separate issue and should be done in a separate patch. Kevin From mboxrd@z Thu Jan 1 00:00:00 1970 From: khilman@deeprootsystems.com (Kevin Hilman) Date: Fri, 01 Oct 2010 07:43:08 -0700 Subject: [PATCH] OMAP2PLUS: WDT: Fix: Disable WDT after reset during init In-Reply-To: (Charulatha Varadarajan's message of "Fri, 1 Oct 2010 19:03:53 +0530") References: <1285834270-32766-1-git-send-email-charu@ti.com> <4CA45341.3080300@ti.com> <87vd5njpyq.fsf@deeprootsystems.com> <4CA49ADE.6080202@ti.com> <20100930150713.GG3117@atomide.com> <87bp7ff962.fsf@deeprootsystems.com> Message-ID: <8762xmdldv.fsf@deeprootsystems.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org "Varadarajan, Charulatha" writes: > Tony, Benoit, Kevin, > >> > >> > > >> > >> > > I think that disabling it should be done only if the >> > CONFIG_OMAP_WDT >> > >> > > is not set. >> > >> > >> > >> > How about disabling is done always unless CONFIG_WATCHDOG_NOWAYOUT >> > >> > is set? >> > >> >> > >> As given in the patch description, this patch does a disable of >> > watchdog >> > >> timer, during init, to avoid the system rebooting that happens due to >> > >> enabling of watchdog timer after a reset of the module (during hwmod >> > init). >> > >> >> > >> According to the default WDT registers values, the system reboot >> would >> > >> happen in ~10s if watchdog is enabled with default values. Hence, >> after >> > >> a WDT module reset during init, the watchdog has to be disabled >> within >> > 10s >> > >> otherwise the system will keep rebooting. >> > >> >> > >> Hence irrespective of CONFIG_WATCHDOG_NOWAYOUT/ CONFIG_OMAP_WDT, >> > >> the watchdog timer needs to be disabled after a WDT reset has >> happened. >> > >> >> > > One more option is to avoid the software reset using the >> CONFIG_OMAP_WDT >> > > flag. Something like below. >> > >> > This was already proposed by Charu, and rejected. >> > >> > Doing this means we have a dependency on particular bootloader init, and >> > we'd like to get rid of *all* assumptions about what the bootloader does >> > (or does not do.) >> > >> you mean is not depeding on bootloader to disable WDT. Make sense. >> > > Let me know your opinion on how to handle this issue. IMO, we should do what your original patch did: always disable the WDT, just like most/all bootloaders do. If we want to make changes later to support product needs (like no disable on boot, etc.) that is a separate issue and should be done in a separate patch. Kevin