watchdog: WatchDog Timer Driver Core - Add minimum and max timeout

Add min_timeout (minimum timeout) and max_timeout
values so that the framework can check if the new
timeout value is between the minimum and maximum
timeout values. If both values are 0, then the
framework will leave the check for the watchdog
device driver itself.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>

diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index 829955bd245e63f72bca4716b9c430b87d191822..4f7c894244d2438cb1d2a7d943136e26e46705ec 100644 (file)
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -43,6 +43,8 @@ struct watchdog_device {
        const struct watchdog_ops *ops;
        unsigned int bootstatus;
        unsigned int timeout;
+       unsigned int min_timeout;
+       unsigned int max_timeout;
        void *driver_data;
        unsigned long status;
 };
@@ -52,6 +54,8 @@ It contains following fields:
   additional information about the watchdog timer itself. (Like it's unique name)
 * ops: a pointer to the list of watchdog operations that the watchdog supports.
 * timeout: the watchdog timer's timeout value (in seconds).
+* min_timeout: the watchdog timer's minimum timeout value (in seconds).
+* max_timeout: the watchdog timer's maximum timeout value (in seconds).
 * bootstatus: status of the device after booting (reported with watchdog
   WDIOF_* status bits).
 * driver_data: a pointer to the drivers private data of a watchdog device.

diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 47fc1267ad4e0d09903edabf6355674bbe968eae..cfa1a1518aadaa19c7d4e296c9ce2e5826e3e5f0 100644 (file)
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -58,6 +58,16 @@ int watchdog_register_device(struct watchdog_device *wdd)
        if (wdd->ops->start == NULL || wdd->ops->stop == NULL)
                return -EINVAL;
 
+       /*
+        * Check that we have valid min and max timeout values, if
+        * not reset them both to 0 (=not used or unknown)
+        */
+       if (wdd->min_timeout > wdd->max_timeout) {
+               pr_info("Invalid min and max timeout values, resetting to 0!\n");
+               wdd->min_timeout = 0;
+               wdd->max_timeout = 0;
+       }
+
        /*
         * Note: now that all watchdog_device data has been verified, we
         * will not check this anymore in other functions. If data gets

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index e7134a5979c61d99cefd3bb49cfef829e1fad19a..d33520d0b4c96f6485e38c3c8fc29fa90a8a5807 100644 (file)
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -220,6 +220,9 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
                        return -EOPNOTSUPP;
                if (get_user(val, p))
                        return -EFAULT;
+               if ((wdd->max_timeout != 0) &&
+                   (val < wdd->min_timeout || val > wdd->max_timeout))
+                               return -EINVAL;
                err = wdd->ops->set_timeout(wdd, val);
                if (err < 0)
                        return err;

diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index 325d90b6641b0cdd80517fa92ddb4eb83f51e793..111843f88b2a97dc87434631335ab95b6e786b45 100644 (file)
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -95,6 +95,8 @@ struct watchdog_ops {
  * @ops:       Pointer to the list of watchdog operations.
  * @bootstatus:        Status of the watchdog device at boot.
  * @timeout:   The watchdog devices timeout value.
+ * @min_timeout:The watchdog devices minimum timeout value.
+ * @max_timeout:The watchdog devices maximum timeout value.
  * @driver-data:Pointer to the drivers private data.
  * @status:    Field that contains the devices internal status bits.
  *
@@ -109,6 +111,8 @@ struct watchdog_device {
        const struct watchdog_ops *ops;
        unsigned int bootstatus;
        unsigned int timeout;
+       unsigned int min_timeout;
+       unsigned int max_timeout;
        void *driver_data;
        unsigned long status;
 /* Bit numbers for status flags */