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Subject[RFC] [PATCH 2/10] Generic Watchdog Timer Driver
commit 79a856016f4f4314360d6efbbbc334828006a79f
Author: Wim Van Sebroeck <wim@iguana.be>
Date: Fri Jun 18 08:58:13 2010 +0000
watchdog: WatchDog Timer Driver Core - Part 2

This part add's the basic ioctl functionality to the
WatchDog Timer Driver Core framework. The supported
ioctl call's are:
WDIOC_GETSUPPORT
WDIOC_GETSTATUS
WDIOC_GETBOOTSTATUS

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/Documentation/watchdog/src/watchdog-with-timer-example.c b/Documentation/watchdog/src/watchdog-with-timer-example.c
index d0b6056..ed7852a 100644
--- a/Documentation/watchdog/src/watchdog-with-timer-example.c
+++ b/Documentation/watchdog/src/watchdog-with-timer-example.c
@@ -115,6 +115,10 @@ static int wdt_stop(struct watchdog_device *wdd)
/*
* The watchdog kernel structures
*/
+static const struct watchdog_info wdt_info = {
+ .identity = DRV_NAME,
+};
+
static const struct watchdog_ops wdt_ops = {
.start = wdt_start,
.stop = wdt_stop,
@@ -123,6 +127,7 @@ static const struct watchdog_ops wdt_ops = {

static struct watchdog_device wdt_dev = {
.name = DRV_NAME,
+ .info = &wdt_info,
.ops = &wdt_ops,
};

diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index e69d1cc..9418d4c 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -40,13 +40,19 @@ The watchdog device structure looks like this:

struct watchdog_device {
char *name;
+ const struct watchdog_info *info;
const struct watchdog_ops *ops;
+ int bootstatus;
long status;
};

It contains following fields:
* name: a pointer to the (preferably unique) name of the watchdog timer device.
+* info: a pointer to a watchdog_info structure. This structure gives some
+ additional information about the watchdog timer itself.
* ops: a pointer to the list of watchdog operations that the watchdog supports.
+* bootstatus: status of the device after booting (reported with watchdog
+ WDIOF_* status bits).
* status: this field contains a number of status bits that give extra
information about the status of the device (Like: is the device opened via
the /dev/watchdog interface or not, ...)
@@ -59,6 +65,7 @@ struct watchdog_ops {
int (*stop)(struct watchdog_device *);
/* optional operations */
int (*ping)(struct watchdog_device *);
+ int (*status)(struct watchdog_device *);
};

Some operations are mandatory and some are optional. The mandatory operations
@@ -89,6 +96,8 @@ they are supported. These optional routines/operations are:
the watchdog timer driver core does: to send a keepalive ping to the watchdog
timer hardware it will either use the ping operation (when available) or the
start operation (when the ping operation is not available).
+* status: this routine checks the status of the watchdog timer device. The
+ status of the device is reported with watchdog WDIOF_* status flags/bits.

The status bits should (preferably) be set with the set_bit and clear_bit alike
bit-operations. The status bit's that are defined are:
diff --git a/drivers/watchdog/core/watchdog_core.c b/drivers/watchdog/core/watchdog_core.c
index d37006c..52bc520 100644
--- a/drivers/watchdog/core/watchdog_core.c
+++ b/drivers/watchdog/core/watchdog_core.c
@@ -57,7 +57,7 @@ int register_watchdogdevice(struct watchdog_device *wdd)
int ret;

/* Make sure we have a valid watchdog_device structure */
- if (wdd == NULL || wdd->ops == NULL)
+ if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL)
return -ENODATA;

/* Make sure that the mandatory operations are supported */
diff --git a/drivers/watchdog/core/watchdog_dev.c b/drivers/watchdog/core/watchdog_dev.c
index 881ca42..ad08a93 100644
--- a/drivers/watchdog/core/watchdog_dev.c
+++ b/drivers/watchdog/core/watchdog_dev.c
@@ -123,6 +123,41 @@ static ssize_t watchdog_write(struct file *file, const char __user *data,
}

/*
+ * watchdog_ioctl: handle the different ioctl's for the watchdog device.
+ * @file: file handle to the device
+ * @cmd: watchdog command
+ * @arg: argument pointer
+ *
+ * The watchdog API defines a common set of functions for all watchdogs
+ * according to their available features.
+ */
+
+static long watchdog_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int val = 0;
+
+ trace("%p, %u, %li", file, cmd, arg);
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, wdd->info,
+ sizeof(struct watchdog_info)) ? -EFAULT : 0;
+ case WDIOC_GETSTATUS:
+ if (wdd->ops->status)
+ val = wdd->ops->status(wdd);
+ return put_user(val, p);
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(wdd->bootstatus, p);
+ default:
+ return -ENOTTY;
+ }
+ return -ENOTTY;
+}
+
+/*
* watchdog_open: open the /dev/watchdog device.
* @inode: inode of device
* @file: file handle to device
@@ -190,6 +225,7 @@ static const struct file_operations watchdog_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = watchdog_write,
+ .unlocked_ioctl = watchdog_ioctl,
.open = watchdog_open,
.release = watchdog_release,
};

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