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Subject[PATCH 05/11] watchdog: WatchDog Timer Driver Core - Add WDIOC_SETTIMEOUT and WDIOC_GETTIMEOUT ioctl
This part add's the WDIOC_SETTIMEOUT and WDIOC_GETTIMEOUT ioctl
functionality to the WatchDog Timer Driver Core framework.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
---
Documentation/watchdog/watchdog-kernel-api.txt | 10 ++++++++++
drivers/watchdog/watchdog_dev.c | 20 ++++++++++++++++++++
include/linux/watchdog.h | 2 ++
3 files changed, 32 insertions(+), 0 deletions(-)
diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index 6df1ade..3085c5c 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -42,6 +42,7 @@ struct watchdog_device {
const struct watchdog_info *info;
const struct watchdog_ops *ops;
unsigned int bootstatus;
+ unsigned int timeout;
void *priv;
unsigned long status;
};
@@ -50,6 +51,7 @@ It contains following fields:
* info: a pointer to a watchdog_info structure. This structure gives some
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).
* bootstatus: status of the device after booting (reported with watchdog
WDIOF_* status bits).
* priv: a pointer to the private data of a watchdog device
@@ -68,6 +70,7 @@ struct watchdog_ops {
/* optional operations */
int (*ping)(struct watchdog_device *);
unsigned int (*status)(struct watchdog_device *);
+ int (*set_timeout)(struct watchdog_device *, unsigned int);
};

It is important that you first define the module owner of the watchdog timer
@@ -105,6 +108,13 @@ they are supported. These optional routines/operations are:
info structure).
* status: this routine checks the status of the watchdog timer device. The
status of the device is reported with watchdog WDIOF_* status flags/bits.
+* set_timeout: this routine checks and changes the timeout of the watchdog
+ timer device. It returns 0 on success, -EINVAL for "parameter out of range"
+ and -EIO for "could not write value to the watchdog". On success the timeout
+ value of the watchdog_device will be changed to the value that was just used
+ to re-program the watchdog timer device.
+ (Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the
+ watchdog's info structure).

The status bits should (preferably) be set with the set_bit and clear_bit alike
bit-operations. The status bits that are defined are:
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 530003b..0d4b16d 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -201,6 +201,26 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
return -EOPNOTSUPP;
watchdog_ping(wdd);
return 0;
+ case WDIOC_SETTIMEOUT:
+ if ((wdd->ops->set_timeout == NULL) ||
+ !(wdd->info->options & WDIOF_SETTIMEOUT))
+ return -EOPNOTSUPP;
+ if (get_user(val, p))
+ return -EFAULT;
+ err = wdd->ops->set_timeout(wdd, val);
+ if (err < 0)
+ return err;
+ wdd->timeout = val;
+ /* If the watchdog is active then we sent a keepalive ping
+ * to make sure that the watchdog keep's running (and if
+ * possible that it takes the new timeout) */
+ watchdog_ping(wdd);
+ /* Fall */
+ case WDIOC_GETTIMEOUT:
+ /* timeout == 0 means that we don't know the timeout */
+ if (wdd->timeout)
+ return put_user(wdd->timeout, p);
+ return -EOPNOTSUPP;
default:
return -ENOTTY;
}
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index 853387f..7e37fdf 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -71,6 +71,7 @@ struct watchdog_ops {
/* optional operations */
int (*ping)(struct watchdog_device *);
unsigned int (*status)(struct watchdog_device *);
+ int (*set_timeout)(struct watchdog_device *, unsigned int);
};

/* The structure that defines a watchdog device */
@@ -78,6 +79,7 @@ struct watchdog_device {
const struct watchdog_info *info;
const struct watchdog_ops *ops;
unsigned int bootstatus;
+ unsigned int timeout;
void *priv;
unsigned long status;
/* Bit numbers for status flags */
--
1.7.6


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