This change adds support for watchdog timer resolution to the watchdog
framework. Two new ioctls are introduced:
- WDIOC_GETRESOLUTION
- WDIOC_SETRESOLUTION
They allow userland applications to retreive and program the watchdog
timer's resolution should the hardware and the driver support it.
---
drivers/watchdog/watchdog_core.c | 14 +++++++++++++
drivers/watchdog/watchdog_dev.c | 41 ++++++++++++++++++++++++++++++++++++++
include/linux/watchdog.h | 12 +++++++++++
include/uapi/linux/watchdog.h | 3 +++
4 files changed, 70 insertions(+)
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 461336c..ca29e64 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -56,6 +56,19 @@ static void watchdog_check_min_max_timeout(struct watchdog_device *wdd)
}
}
+static void watchdog_check_min_max_resolution(struct watchdog_device *wdd)
+{
+ /*
+ * Check that we have valid min and max timeout values, if
+ * not reset them both to 0 (=not used or unknown)
+ */
+ if (wdd->min_resolution > wdd->max_resolution) {
+ pr_info("Invalid min & max resolution values, setting to 0!\n");
+ wdd->min_resolution = 0;
+ wdd->max_resolution = 0;
+ }
+}
+
/**
* watchdog_init_timeout() - initialize the timeout field
* @timeout_parm: timeout module parameter
@@ -120,6 +133,7 @@ int watchdog_register_device(struct watchdog_device *wdd)
return -EINVAL;
watchdog_check_min_max_timeout(wdd);
+ watchdog_check_min_max_resolution(wdd);
/*
* Note: now that all watchdog_device data has been verified, we
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 6aaefba..fd4ea61 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -218,6 +218,37 @@ out_timeout:
}
/*
+ * watchdog_set_resolution: set the watchdog timer resolution
+ * @wddev: the watchdog device to set the resolution for
+ * @resolution: timer resolution (in native format)
+ */
+static int watchdog_set_resolution(struct watchdog_device *wddev,
+ unsigned int resolution)
+{
+ int err;
+
+ if ((wddev->ops->set_resolution == NULL) ||
+ !(wddev->info->options & WDIOF_SETRESOLUTION))
+ return -EOPNOTSUPP;
+
+ if (watchdog_resolution_invalid(wddev, resolution))
+ return -EINVAL;
+
+ mutex_lock(&wddev->lock);
+
+ if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+ err = -ENODEV;
+ goto out_resolution;
+ }
+
+ err = wddev->ops->set_resolution(wddev, resolution);
+
+out_resolution:
+ mutex_unlock(&wddev->lock);
+ return err;
+}
+
+/*
* watchdog_get_timeleft: wrapper to get the time left before a reboot
* @wddev: the watchdog device to get the remaining time from
* @timeleft: the time that's left
@@ -393,6 +424,16 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
if (err)
return err;
return put_user(val, p);
+ case WDIOC_SETRESOLUTION:
+ if (get_user(val, p))
+ return -EFAULT;
+ err = watchdog_set_resolution(wdd, val);
+ if (err < 0)
+ return err;
+ watchdog_ping(wdd);
+ return 0;
+ case WDIOC_GETRESOLUTION:
+ return put_user(wdd->resolution, p);
default:
return -ENOTTY;
}
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index 2a3038e..c9b0a4dc 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -25,6 +25,7 @@ struct watchdog_device;
* @ping: The routine that sends a keepalive ping to the watchdog device.
* @status: The routine that shows the status of the watchdog device.
* @set_timeout:The routine for setting the watchdog devices timeout value.
+ * @set_resolution:The routine for setting the timer resolution value.
* @get_timeleft:The routine that get's the time that's left before a reset.
* @ref: The ref operation for dyn. allocated watchdog_device structs
* @unref: The unref operation for dyn. allocated watchdog_device structs
@@ -44,6 +45,7 @@ struct watchdog_ops {
int (*ping)(struct watchdog_device *);
unsigned int (*status)(struct watchdog_device *);
int (*set_timeout)(struct watchdog_device *, unsigned int);
+ int (*set_resolution)(struct watchdog_device *, unsigned int);
unsigned int (*get_timeleft)(struct watchdog_device *);
void (*ref)(struct watchdog_device *);
void (*unref)(struct watchdog_device *);
@@ -86,6 +88,9 @@ struct watchdog_device {
unsigned int timeout;
unsigned int min_timeout;
unsigned int max_timeout;
+ unsigned int resolution;
+ unsigned int min_resolution;
+ unsigned int max_resolution;
void *driver_data;
struct mutex lock;
unsigned long status;
@@ -125,6 +130,13 @@ static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigne
(t < wdd->min_timeout || t > wdd->max_timeout));
}
+/* Use the following function to check if a resolution value is invalid */
+static inline bool watchdog_resolution_invalid(struct watchdog_device *wdd, unsigned int r)
+{
+ return ((wdd->max_resolution != 0) &&
+ (r < wdd->min_resolution || r > wdd->max_resolution));
+}
+
/* Use the following functions to manipulate watchdog driver specific data */
static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
{
diff --git a/include/uapi/linux/watchdog.h b/include/uapi/linux/watchdog.h
index 2babe72..15cab9b 100644
--- a/include/uapi/linux/watchdog.h
+++ b/include/uapi/linux/watchdog.h
@@ -31,6 +31,8 @@ struct watchdog_info {
#define WDIOC_SETPRETIMEOUT _IOWR(WATCHDOG_IOCTL_BASE, 8, int)
#define WDIOC_GETPRETIMEOUT _IOR(WATCHDOG_IOCTL_BASE, 9, int)
#define WDIOC_GETTIMELEFT _IOR(WATCHDOG_IOCTL_BASE, 10, int)
+#define WDIOC_GETRESOLUTION _IOR(WATCHDOG_IOCTL_BASE, 11, int)
+#define WDIOC_SETRESOLUTION _IOWR(WATCHDOG_IOCTL_BASE, 12, int)
#define WDIOF_UNKNOWN -1 /* Unknown flag error */
#define WDIOS_UNKNOWN -1 /* Unknown status error */
@@ -47,6 +49,7 @@ struct watchdog_info {
#define WDIOF_PRETIMEOUT 0x0200 /* Pretimeout (in seconds), get/set */
#define WDIOF_ALARMONLY 0x0400 /* Watchdog triggers a management or
other external alarm not a reboot */
+#define WDIOF_SETRESOLUTION 0x0800 /* Set resolution */
#define WDIOF_KEEPALIVEPING 0x8000 /* Keep alive ping reply */
#define WDIOS_DISABLECARD 0x0001 /* Turn off the watchdog timer */
--
1.7.9.5
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