PM / watchdog: iTCO: stop watchdog during system suspend

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-and-tested-by: Borun Fu <borun.fu@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net>

PM / watchdog: iTCO: stop watchdog during system suspend
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-and-tested-by: Borun Fu <borun.fu@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Rafael J. Wysocki
1 parent 431d452af1
Showing 1 changed file with 51 additions and 0 deletions Side-by-side Diff
drivers/watchdog/iTCO_wdt.c
@@ -51,6 +51,7 @@
 #define DRV_VERSION	"1.11"
  
 /* Includes */
+#include <linux/acpi.h>			/* For ACPI support */
 #include <linux/module.h>		/* For module specific items */
 #include <linux/moduleparam.h>		/* For new moduleparam's */
 #include <linux/types.h>		/* For standard types (like size_t) */
@@ -103,6 +104,8 @@
 	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 @@
 	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;
+}
+
+static 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,
 	},
 };
...	...	@@ -51,6 +51,7 @@
51	51	#define DRV_VERSION "1.11"
52	52
53	53	/* Includes */
	54	+#include <linux/acpi.h> /* For ACPI support */
54	55	#include <linux/module.h> /* For module specific items */
55	56	#include <linux/moduleparam.h> /* For new moduleparam's */
56	57	#include <linux/types.h> /* For standard types (like size_t) */
...	...	@@ -103,6 +104,8 @@
103	104	struct platform_device *dev;
104	105	/* the PCI-device */
105	106	struct pci_dev *pdev;
	107	+ /* whether or not the watchdog has been suspended */
	108	+ bool suspended;
106	109	} iTCO_wdt_private;
107	110
108	111	/* module parameters */
109	112
...	...	@@ -571,12 +574,60 @@
571	574	iTCO_wdt_stop(NULL);
572	575	}
573	576
	577	+#ifdef CONFIG_PM_SLEEP
	578	+/*
	579	+ * Suspend-to-idle requires this, because it stops the ticks and timekeeping, so
	580	+ * the watchdog cannot be pinged while in that state. In ACPI sleep states the
	581	+ * watchdog is stopped by the platform firmware.
	582	+ */
	583	+
	584	+#ifdef CONFIG_ACPI
	585	+static inline bool need_suspend(void)
	586	+{
	587	+ return acpi_target_system_state() == ACPI_STATE_S0;
	588	+}
	589	+#else
	590	+static inline bool need_suspend(void) { return true; }
	591	+#endif
	592	+
	593	+static int iTCO_wdt_suspend_noirq(struct device *dev)
	594	+{
	595	+ int ret = 0;
	596	+
	597	+ iTCO_wdt_private.suspended = false;
	598	+ if (watchdog_active(&iTCO_wdt_watchdog_dev) && need_suspend()) {
	599	+ ret = iTCO_wdt_stop(&iTCO_wdt_watchdog_dev);
	600	+ if (!ret)
	601	+ iTCO_wdt_private.suspended = true;
	602	+ }
	603	+ return ret;
	604	+}
	605	+
	606	+static int iTCO_wdt_resume_noirq(struct device *dev)
	607	+{
	608	+ if (iTCO_wdt_private.suspended)
	609	+ iTCO_wdt_start(&iTCO_wdt_watchdog_dev);
	610	+
	611	+ return 0;
	612	+}
	613	+
	614	+static struct dev_pm_ops iTCO_wdt_pm = {
	615	+ .suspend_noirq = iTCO_wdt_suspend_noirq,
	616	+ .resume_noirq = iTCO_wdt_resume_noirq,
	617	+};
	618	+
	619	+#define ITCO_WDT_PM_OPS (&iTCO_wdt_pm)
	620	+#else
	621	+#define ITCO_WDT_PM_OPS NULL
	622	+#endif /* CONFIG_PM_SLEEP */
	623	+
574	624	static struct platform_driver iTCO_wdt_driver = {
575	625	.probe = iTCO_wdt_probe,
576	626	.remove = iTCO_wdt_remove,
577	627	.shutdown = iTCO_wdt_shutdown,
578	628	.driver = {
579	629	.name = DRV_NAME,
	630	+ .pm = ITCO_WDT_PM_OPS,
580	631	},
581	632	};
582	633