From patchwork Fri Jul 17 13:29:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tero Kristo X-Patchwork-Id: 11670247 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9702F159A for ; Fri, 17 Jul 2020 13:30:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7AF8D2083B for ; Fri, 17 Jul 2020 13:30:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="ha9xdr5c" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726383AbgGQNas (ORCPT ); Fri, 17 Jul 2020 09:30:48 -0400 Received: from fllv0016.ext.ti.com ([198.47.19.142]:39676 "EHLO fllv0016.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726852AbgGQNas (ORCPT ); Fri, 17 Jul 2020 09:30:48 -0400 Received: from fllv0035.itg.ti.com ([10.64.41.0]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 06HDUBdD052006; Fri, 17 Jul 2020 08:30:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1594992611; bh=1f8QGphM1gDJrV+uk7tlCewgRrYPd1fn7gpp9JJzAS0=; h=From:To:CC:Subject:Date:In-Reply-To:References; b=ha9xdr5caMQ9HSqkgqjaXI0k7GcV8aBYkZVJoojL6WdL76SULLHnqN4n5Cnbu+7UY 4MOoHS+0GxySsIzt2rER4QqPCgy0ULc20vce7m80L8iJ3C/fRJotuqmRmiXopISStW h7lgUhYZwakuVgqgfdxwO+LzgMTPky5kVFMnA6BM= Received: from DFLE113.ent.ti.com (dfle113.ent.ti.com [10.64.6.34]) by fllv0035.itg.ti.com (8.15.2/8.15.2) with ESMTP id 06HDUBup075551; Fri, 17 Jul 2020 08:30:11 -0500 Received: from DFLE103.ent.ti.com (10.64.6.24) by DFLE113.ent.ti.com (10.64.6.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Fri, 17 Jul 2020 08:30:11 -0500 Received: from lelv0326.itg.ti.com (10.180.67.84) by DFLE103.ent.ti.com (10.64.6.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3 via Frontend Transport; Fri, 17 Jul 2020 08:30:11 -0500 Received: from sokoban.bb.dnainternet.fi (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 06HDU5Ld051528; Fri, 17 Jul 2020 08:30:09 -0500 From: Tero Kristo To: , , CC: , Subject: [PATCHv4 2/4] watchdog: add support for adjusting last known HW keepalive time Date: Fri, 17 Jul 2020 16:29:56 +0300 Message-ID: <20200717132958.14304-3-t-kristo@ti.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200717132958.14304-1-t-kristo@ti.com> References: <20200717132958.14304-1-t-kristo@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Certain watchdogs require the watchdog only to be pinged within a specific time window, pinging too early or too late cause the watchdog to fire. In cases where this sort of watchdog has been started before kernel comes up, we must adjust the watchdog keepalive window to match the actually running timer, so add a new driver API for this purpose. Signed-off-by: Tero Kristo Reviewed-by: Guenter Roeck --- .../watchdog/watchdog-kernel-api.rst | 12 ++++++++ drivers/watchdog/watchdog_dev.c | 30 +++++++++++++++++++ include/linux/watchdog.h | 2 ++ 3 files changed, 44 insertions(+) diff --git a/Documentation/watchdog/watchdog-kernel-api.rst b/Documentation/watchdog/watchdog-kernel-api.rst index 068a55ee0d4a..baf44e986b07 100644 --- a/Documentation/watchdog/watchdog-kernel-api.rst +++ b/Documentation/watchdog/watchdog-kernel-api.rst @@ -336,3 +336,15 @@ an action is taken by a preconfigured pretimeout governor preassigned to the watchdog device. If watchdog pretimeout governor framework is not enabled, watchdog_notify_pretimeout() prints a notification message to the kernel log buffer. + +To set the last known HW keepalive time for a watchdog, the following function +should be used:: + + int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd, + unsigned int last_ping_ms) + +This function must be called immediately after watchdog registration. It +sets the last known hardware heartbeat to have happened last_ping_ms before +current time. Calling this is only needed if the watchdog is already running +when probe is called, and the watchdog can only be pinged after the +min_hw_heartbeat_ms time has passed from the last ping. diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index bc1cfa288553..e74a0c6811b5 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -1138,6 +1138,36 @@ void watchdog_dev_unregister(struct watchdog_device *wdd) watchdog_cdev_unregister(wdd); } +/* + * watchdog_set_last_hw_keepalive: set last HW keepalive time for watchdog + * @wdd: watchdog device + * @last_ping_ms: time since last HW heartbeat + * + * Adjusts the last known HW keepalive time for a watchdog timer. + * This is needed if the watchdog is already running when the probe + * function is called, and it can't be pinged immediately. This + * function must be called immediately after watchdog registration, + * and min_hw_heartbeat_ms must be set for this to be useful. + */ +int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd, + unsigned int last_ping_ms) +{ + struct watchdog_core_data *wd_data; + ktime_t now; + + if (!wdd) + return -EINVAL; + + wd_data = wdd->wd_data; + + now = ktime_get(); + + wd_data->last_hw_keepalive = ktime_sub(now, ms_to_ktime(last_ping_ms)); + + return __watchdog_ping(wdd); +} +EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive); + /* * watchdog_dev_init: init dev part of watchdog core * diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 1464ce6ffa31..9b19e6bb68b5 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -210,6 +210,8 @@ extern int watchdog_init_timeout(struct watchdog_device *wdd, extern int watchdog_register_device(struct watchdog_device *); extern void watchdog_unregister_device(struct watchdog_device *); +int watchdog_set_last_hw_keepalive(struct watchdog_device *, unsigned int); + /* devres register variant */ int devm_watchdog_register_device(struct device *dev, struct watchdog_device *);