From patchwork Tue Jun 15 12:39:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Grzegorz Jaszczyk X-Patchwork-Id: 12321239 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 4439EC49EA2 for ; Tue, 15 Jun 2021 12:39:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2676661463 for ; Tue, 15 Jun 2021 12:39:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230113AbhFOMlW (ORCPT ); Tue, 15 Jun 2021 08:41:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229979AbhFOMlT (ORCPT ); Tue, 15 Jun 2021 08:41:19 -0400 Received: from mail-lj1-x231.google.com (mail-lj1-x231.google.com [IPv6:2a00:1450:4864:20::231]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 43426C061767 for ; Tue, 15 Jun 2021 05:39:14 -0700 (PDT) Received: by mail-lj1-x231.google.com with SMTP id 131so24863079ljj.3 for ; Tue, 15 Jun 2021 05:39:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=3pEsLcQ/8PBueEyiqA/kBMEdoALnX+fHc+Skgy5Wse4=; b=Lo9MxugjizgQOg5AcVDyMzvLOktI70lW6BqlHYqn00ELIrDqv7V6Ov0lEQBnp5sUVD MEPCbDZuIh8/nel5c0auOPPLNOU1H5uIjDc5vhxFBss4iCdhMUGN4yXFTkQTjBA5tCqL QSweT1vPd5k3r6/wIVz2sAPIKrLLhjUZoy0MdVzBIqa6GfCi7DXrgMbCvsglVKzATE/v U2ntj3TKpDWL/fdjmifyV7fEFa9yXls5YSBx9Z7CfljNUaX8KAokcCIBmkJWHmifwOxZ Zo5LCFEfPs+mr2AHHq8fv1wP4akbn6uuxYtycGEU+5Q2vfV0FpH0JafAhiXQ/edCTEyb YM3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=3pEsLcQ/8PBueEyiqA/kBMEdoALnX+fHc+Skgy5Wse4=; b=AsZbzK3Kq9rguOazWooR8s1QTQpzOt8aMXgXT/MyklcA0tN7+doqsbO/2WnuBQyjbj qpONHO5vJ1uHwEvXJKDztjfSSSiiEwagK+i2+okAjk08VgcQqwqWddcpOgkr4hYrRTUk CVh4ZKDC5avufvQGN1CTHQHJ9KTI86pYX5aZetbXiHUSzRGywxDoKSWCfq+PIHcT4tdR KSnDbRCsnpSPBLBSEBvOb6C2+5Z3sEilyrLmbLbyX8y7/mIBhvF1zF+XDVZS7KpJj3DU oaQpotmMKR0uTivBEuo2uXLxZZxDaVS/fqP6K4DuSEnRi9NK/+hfIkUC0ZuZhluPDo9d Hb/A== X-Gm-Message-State: AOAM530Z/OuID5JS/kax0v176JRidaEGXp2DiT30i94Oh+srMxZGVuht wmTtsANY2orFO/GqFa2ZiDFWXQ== X-Google-Smtp-Source: ABdhPJwRsf+yNOWqXkRPrg7C6+J4ziUSxP9L+WvAbfpgF/03zjoPDhYxMZParIYV9z2a3UBO/FrilQ== X-Received: by 2002:a2e:6c0e:: with SMTP id h14mr17848984ljc.267.1623760752547; Tue, 15 Jun 2021 05:39:12 -0700 (PDT) Received: from gilgamesh.lab.semihalf.net ([83.142.187.85]) by smtp.gmail.com with ESMTPSA id m12sm811418lfb.231.2021.06.15.05.39.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Jun 2021 05:39:12 -0700 (PDT) From: Grzegorz Jaszczyk To: wim@linux-watchdog.org, linux@roeck-us.net, shawnguo@kernel.org Cc: linux-watchdog@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, grzegorz.jaszczyk@linaro.org Subject: [PATCH 1/2] watchdog: introduce watchdog_dev_suspend/resume Date: Tue, 15 Jun 2021 14:39:03 +0200 Message-Id: <20210615123904.2568052-2-grzegorz.jaszczyk@linaro.org> X-Mailer: git-send-email 2.29.0 In-Reply-To: <20210615123904.2568052-1-grzegorz.jaszczyk@linaro.org> References: <20210615123904.2568052-1-grzegorz.jaszczyk@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org The watchdog drivers often disable wdog clock during suspend and then enable it again during resume. Nevertheless the ping worker is still running and can issue low-level ping while the wdog clock is disabled causing the system hang. To prevent such condition introduce watchdog_dev_suspend/resume which can be used by any wdog driver and actually cancel ping worker during suspend and restore it back, if needed, during resume. Signed-off-by: Grzegorz Jaszczyk Reported-by: kernel test robot --- drivers/watchdog/watchdog_dev.c | 49 +++++++++++++++++++++++++++++++++ include/linux/watchdog.h | 2 ++ 2 files changed, 51 insertions(+) diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 2946f3a63110..3feca1567281 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -1219,6 +1219,55 @@ void __exit watchdog_dev_exit(void) kthread_destroy_worker(watchdog_kworker); } +int watchdog_dev_suspend(struct watchdog_device *wdd) +{ + struct watchdog_core_data *wd_data = wdd->wd_data; + int ret; + + if (!wdd->wd_data) + return -ENODEV; + + /* ping for the last time before suspend */ + mutex_lock(&wd_data->lock); + if (watchdog_worker_should_ping(wd_data)) + ret = __watchdog_ping(wd_data->wdd); + mutex_unlock(&wd_data->lock); + + if (ret) + return ret; + + /* + * make sure that watchdog worker will not kick in when the wdog is + * suspended + */ + hrtimer_cancel(&wd_data->timer); + kthread_cancel_work_sync(&wd_data->work); + + return 0; +} +EXPORT_SYMBOL_GPL(watchdog_dev_suspend); + +int watchdog_dev_resume(struct watchdog_device *wdd) +{ + struct watchdog_core_data *wd_data = wdd->wd_data; + int ret; + + if (!wdd->wd_data) + return -ENODEV; + + /* + * __watchdog_ping will also retrigger hrtimer and therefore restore the + * ping worker if needed. + */ + mutex_lock(&wd_data->lock); + if (watchdog_worker_should_ping(wd_data)) + ret = __watchdog_ping(wd_data->wdd); + mutex_unlock(&wd_data->lock); + + return ret; +} +EXPORT_SYMBOL_GPL(watchdog_dev_resume); + module_param(handle_boot_enabled, bool, 0444); MODULE_PARM_DESC(handle_boot_enabled, "Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default=" diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 9b19e6bb68b5..febfde3b1ff6 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -209,6 +209,8 @@ extern int watchdog_init_timeout(struct watchdog_device *wdd, unsigned int timeout_parm, struct device *dev); extern int watchdog_register_device(struct watchdog_device *); extern void watchdog_unregister_device(struct watchdog_device *); +int watchdog_dev_suspend(struct watchdog_device *wdd); +int watchdog_dev_resume(struct watchdog_device *wdd); int watchdog_set_last_hw_keepalive(struct watchdog_device *, unsigned int); From patchwork Tue Jun 15 12:39:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Grzegorz Jaszczyk X-Patchwork-Id: 12321237 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 4E85AC48BE5 for ; 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Tue, 15 Jun 2021 05:39:13 -0700 (PDT) Received: from gilgamesh.lab.semihalf.net ([83.142.187.85]) by smtp.gmail.com with ESMTPSA id m12sm811418lfb.231.2021.06.15.05.39.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Jun 2021 05:39:13 -0700 (PDT) From: Grzegorz Jaszczyk To: wim@linux-watchdog.org, linux@roeck-us.net, shawnguo@kernel.org Cc: linux-watchdog@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, grzegorz.jaszczyk@linaro.org, Michal Koziel Subject: [PATCH 2/2] watchdog: imx2_wdg: notify wdog subsystem about wdog suspend/resume Date: Tue, 15 Jun 2021 14:39:04 +0200 Message-Id: <20210615123904.2568052-3-grzegorz.jaszczyk@linaro.org> X-Mailer: git-send-email 2.29.0 In-Reply-To: <20210615123904.2568052-1-grzegorz.jaszczyk@linaro.org> References: <20210615123904.2568052-1-grzegorz.jaszczyk@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Suspend routine disables wdog clk. Nevertheless, the watchdog subsystem is not aware of that and can still try to ping wdog through watchdog_ping_work. In order to prevent such condition and therefore prevent from system hang (caused by the wdog register access issued while the wdog clock is disabled) take advantage of watchdog_dev_suspend/resume routines which will take care of watchdog ping worker cancel and restore. Additionally remove hw ping from suspend/resume since it will be issued by watchdog_dev_suspend/resume routines. Signed-off-by: Michal Koziel Signed-off-by: Grzegorz Jaszczyk --- drivers/watchdog/imx2_wdt.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c index b84f80f7d342..24e3a4d2b529 100644 --- a/drivers/watchdog/imx2_wdt.c +++ b/drivers/watchdog/imx2_wdt.c @@ -348,6 +348,17 @@ static int __maybe_unused imx2_wdt_suspend(struct device *dev) { struct watchdog_device *wdog = dev_get_drvdata(dev); struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog); + int ret; + + /* + * Before disabling clk we need to notify wdog subsystem that HW wdog + * is being suspended. This e.g. prevents watchdog_ping_work to fire + * when the clk is disabled, which would result with system hang caused + * by wdog register access while wdog clock is disabled. + */ + ret = watchdog_dev_suspend(wdog); + if (ret) + return ret; /* The watchdog IP block is running */ if (imx2_wdt_is_running(wdev)) { @@ -356,7 +367,6 @@ static int __maybe_unused imx2_wdt_suspend(struct device *dev) * during resume. */ __imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME); - imx2_wdt_ping(wdog); } clk_disable_unprepare(wdev->clk); @@ -383,12 +393,12 @@ static int __maybe_unused imx2_wdt_resume(struct device *dev) */ imx2_wdt_setup(wdog); } - if (imx2_wdt_is_running(wdev)) { + if (imx2_wdt_is_running(wdev)) imx2_wdt_set_timeout(wdog, wdog->timeout); - imx2_wdt_ping(wdog); - } - return 0; + ret = watchdog_dev_resume(wdog); + + return ret; } static SIMPLE_DEV_PM_OPS(imx2_wdt_pm_ops, imx2_wdt_suspend,