From patchwork Tue Apr 13 10:20:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Flavio Suligoi X-Patchwork-Id: 420634 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5DCE3C433B4 for ; Tue, 13 Apr 2021 10:20:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 371A7613BB for ; Tue, 13 Apr 2021 10:20:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241803AbhDMKU6 (ORCPT ); Tue, 13 Apr 2021 06:20:58 -0400 Received: from smtp.asem.it ([151.1.184.197]:54000 "EHLO smtp.asem.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229835AbhDMKU4 (ORCPT ); Tue, 13 Apr 2021 06:20:56 -0400 Received: from webmail.asem.it by asem.it (smtp.asem.it) (SecurityGateway 8.0.0) with ESMTP id 2af592a94e7142a3b507e2107c860276.MSG for ; Tue, 13 Apr 2021 12:20:34 +0200S Received: from ASAS044.asem.intra (172.16.16.44) by ASAS044.asem.intra (172.16.16.44) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Tue, 13 Apr 2021 12:20:31 +0200 Received: from flavio-x.asem.intra (172.16.17.208) by ASAS044.asem.intra (172.16.16.44) with Microsoft SMTP Server id 15.1.2176.2 via Frontend Transport; Tue, 13 Apr 2021 12:20:31 +0200 From: Flavio Suligoi To: Wim Van Sebroeck , Guenter Roeck CC: Mika Westerberg , , , Flavio Suligoi Subject: [PATCH v2] watchdog: add new parameter to start the watchdog on module insertion Date: Tue, 13 Apr 2021 12:20:30 +0200 Message-ID: <20210413102030.3204571-1-f.suligoi@asem.it> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-SGHeloLookup-Result: pass smtp.helo=webmail.asem.it (ip=172.16.16.44) X-SGSPF-Result: none (smtp.asem.it) X-SGOP-RefID: str=0001.0A782F28.60757070.0089, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0 (_st=1 _vt=0 _iwf=0) Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org The new parameter "start_enabled" starts the watchdog at the same time of the module insertion. This feature is very useful in embedded systems, to avoid cases where the system hangs before reaching userspace. This feature can be enabled in the kernel config, so it can be also used when the watchdog driver is build as "built-in". This parameter involves the "core" section of the watchdog driver; in this way it is common for all the watchdog hardware implementations. Signed-off-by: Flavio Suligoi --- v2: - check WDOG_HW_RUNNING before starting watchdog; - remove useless comments in commit text, watchdog-parameters.rst and Kconfig; v1: - first version; Documentation/watchdog/watchdog-parameters.rst | 3 +++ drivers/watchdog/Kconfig | 9 +++++++++ drivers/watchdog/watchdog_core.c | 12 ++++++++++++ 3 files changed, 24 insertions(+) diff --git a/Documentation/watchdog/watchdog-parameters.rst b/Documentation/watchdog/watchdog-parameters.rst index 223c99361a30..7780d0c1fb4a 100644 --- a/Documentation/watchdog/watchdog-parameters.rst +++ b/Documentation/watchdog/watchdog-parameters.rst @@ -21,6 +21,9 @@ watchdog core: timeout. Setting this to a non-zero value can be useful to ensure that either userspace comes up properly, or the board gets reset and allows fallback logic in the bootloader to try something else. + start_enabled: + Watchdog is started on module insertion. This option can be also + selected by kernel config (default=kernel config parameter). ------------------------------------------------- diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 0470dc15c085..1c480f4c7f94 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -47,6 +47,15 @@ config WATCHDOG_NOWAYOUT get killed. If you say Y here, the watchdog cannot be stopped once it has been started. +config WATCHDOG_START_ENABLED + bool "Start watchdog on module insertion" + help + Say Y if you want to start the watchdog at the same time when the + driver is loaded. + This feature is very useful in embedded systems, to avoid cases where + the system could hang before reaching userspace. + This parameter applies to all watchdog drivers. + config WATCHDOG_HANDLE_BOOT_ENABLED bool "Update boot-enabled watchdog until userspace takes over" default y diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c index 5df0a22e2cb4..8a1e2e9331ee 100644 --- a/drivers/watchdog/watchdog_core.c +++ b/drivers/watchdog/watchdog_core.c @@ -43,6 +43,11 @@ static int stop_on_reboot = -1; module_param(stop_on_reboot, int, 0444); MODULE_PARM_DESC(stop_on_reboot, "Stop watchdogs on reboot (0=keep watching, 1=stop)"); +static bool start_enabled = IS_ENABLED(CONFIG_WATCHDOG_START_ENABLED); +module_param(start_enabled, bool, 0444); +MODULE_PARM_DESC(start_enabled, "Start watchdog on module insertion (default=" + __MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_START_ENABLED)) ")"); + /* * Deferred Registration infrastructure. * @@ -224,6 +229,13 @@ static int __watchdog_register_device(struct watchdog_device *wdd) * corrupted in a later stage then we expect a kernel panic! */ + /* If required, start the watchdog immediately */ + if (start_enabled && !watchdog_hw_running(wdd)) { + set_bit(WDOG_HW_RUNNING, &wdd->status); + wdd->ops->start(wdd); + pr_info("Watchdog enabled\n"); + } + /* Use alias for watchdog id if possible */ if (wdd->parent) { ret = of_alias_get_id(wdd->parent->of_node, "watchdog");