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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-04-03 15:25:04 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-04-03 15:25:04 +0200
commitf321c9cbf3bbf86f6e6153419eaf93ad085e3d74 (patch)
tree8326d454c934c8833ecc7e365c2cb52f0f0616be /drivers/watchdog
parent431d452af13720463dda498999b2e9a08729c03a (diff)
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>
Diffstat (limited to 'drivers/watchdog')
-rw-r--r--drivers/watchdog/iTCO_wdt.c51
1 files changed, 51 insertions, 0 deletions
diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index 05ee0bf88ce9..3c3fd417ddeb 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/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 @@ static struct { /* this is private data for the iTCO_wdt device */
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 platform_device *dev)
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,
},
};