From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752570AbbDBAGt (ORCPT ); Wed, 1 Apr 2015 20:06:49 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:63915 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751576AbbDBAGr (ORCPT ); Wed, 1 Apr 2015 20:06:47 -0400 From: "Rafael J. Wysocki" To: linux-watchdog@vger.kernel.org Cc: Linux Kernel Mailing List , Linux PM list , Wim Van Sebroeck , Aubrey Li , Borun Fu Subject: [PATCH] PM / watchdog: iTCO: stop watchdog during system suspend Date: Thu, 02 Apr 2015 02:31:01 +0200 Message-ID: <2017660.nPaHVT8bW3@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.19.0+; KDE/4.11.5; x86_64; ; ) MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki If the target sleep state of the system is not an ACPI sleep state (S1, S2 or S3), the TCO watchdog needs to be stopped during system suspend, because it may not be possible to ping it any more after timekeeping has been suspended (suspend-to-idle does that for one example). For this reason, provide ->suspend_noirq and ->resume_noirq callbacks for the iTCO watchdog driver and use them to stop and restart the watchdog during system suspend and resume, respectively, if the system is not going to enter an ACPI sleep state (in which case the watchdog will be stopped by the platform firmware before the state is entered). Reported-by: Borun Fu Signed-off-by: Rafael J. Wysocki --- drivers/watchdog/iTCO_wdt.c | 51 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) Index: linux-pm/drivers/watchdog/iTCO_wdt.c =================================================================== --- linux-pm.orig/drivers/watchdog/iTCO_wdt.c +++ linux-pm/drivers/watchdog/iTCO_wdt.c @@ -51,6 +51,7 @@ #define DRV_VERSION "1.11" /* Includes */ +#include /* For ACPI support */ #include /* For module specific items */ #include /* For new moduleparam's */ #include /* For standard types (like size_t) */ @@ -103,6 +104,8 @@ static struct { /* this is private data struct platform_device *dev; /* the PCI-device */ struct pci_dev *pdev; + /* whether or not the watchdog has been suspended */ + bool suspended; } iTCO_wdt_private; /* module parameters */ @@ -571,12 +574,60 @@ static void iTCO_wdt_shutdown(struct pla iTCO_wdt_stop(NULL); } +#ifdef CONFIG_PM_SLEEP +/* + * Suspend-to-idle requires this, because it stops the ticks and timekeeping, so + * the watchdog cannot be pinged while in that state. In ACPI sleep states the + * watchdog is stopped by the platform firmware. + */ + +#ifdef CONFIG_ACPI +static inline bool need_suspend(void) +{ + return acpi_target_system_state() == ACPI_STATE_S0; +} +#else +static inline bool need_suspend(void) { return true; } +#endif + +static int iTCO_wdt_suspend_noirq(struct device *dev) +{ + int ret = 0; + + iTCO_wdt_private.suspended = false; + if (watchdog_active(&iTCO_wdt_watchdog_dev) && need_suspend()) { + ret = iTCO_wdt_stop(&iTCO_wdt_watchdog_dev); + if (!ret) + iTCO_wdt_private.suspended = true; + } + return ret; +} + +static int iTCO_wdt_resume_noirq(struct device *dev) +{ + if (iTCO_wdt_private.suspended) + iTCO_wdt_start(&iTCO_wdt_watchdog_dev); + + return 0; +} + +struct dev_pm_ops iTCO_wdt_pm = { + .suspend_noirq = iTCO_wdt_suspend_noirq, + .resume_noirq = iTCO_wdt_resume_noirq, +}; + +#define ITCO_WDT_PM_OPS &iTCO_wdt_pm +#else +#define ITCO_WDT_PM_OPS NULL +#endif /* CONFIG_PM_SLEEP */ + static struct platform_driver iTCO_wdt_driver = { .probe = iTCO_wdt_probe, .remove = iTCO_wdt_remove, .shutdown = iTCO_wdt_shutdown, .driver = { .name = DRV_NAME, + .pm = ITCO_WDT_PM_OPS, }, };