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watchdog: WatchDog Timer Driver Core - Add basic ioctl functionality

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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>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
This commit is contained in:
Wim Van Sebroeck 2011-07-22 18:56:38 +00:00
parent 43316044d4
commit 2fa03560ab
3 changed files with 42 additions and 0 deletions
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6
Documentation/watchdog/watchdog-kernel-api.txt
View file

@ -41,6 +41,7 @@ The watchdog device structure looks like this:
struct watchdog_device {
const struct watchdog_info *info;
const struct watchdog_ops *ops;
unsigned int bootstatus;
void *driver_data;
unsigned long status;
};
@ -49,6 +50,8 @@ 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.
* 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.
This data should only be accessed via the watchdog_set_drvadata and
watchdog_get_drvdata routines.
@ -65,6 +68,7 @@ struct watchdog_ops {
int (*stop)(struct watchdog_device *);
/* optional operations */
int (*ping)(struct watchdog_device *);
unsigned int (*status)(struct watchdog_device *);
};
It is important that you first define the module owner of the watchdog timer
@ -97,6 +101,8 @@ 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 bits that are defined are:

32
drivers/watchdog/watchdog_dev.c
View file

@ -94,6 +94,37 @@ static ssize_t watchdog_write(struct file *file, const char __user *data,
return len;
}
/*
* 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;
unsigned int val;
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, wdd->info,
sizeof(struct watchdog_info)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
val = wdd->ops->status ? wdd->ops->status(wdd) : 0;
return put_user(val, p);
case WDIOC_GETBOOTSTATUS:
return put_user(wdd->bootstatus, p);
default:
return -ENOTTY;
}
}
/*
* watchdog_open: open the /dev/watchdog device.
* @inode: inode of device
@ -163,6 +194,7 @@ static int watchdog_release(struct inode *inode, struct file *file)
static const struct file_operations watchdog_fops = {
.owner = THIS_MODULE,
.write = watchdog_write,
.unlocked_ioctl = watchdog_ioctl,
.open = watchdog_open,
.release = watchdog_release,
};

4
include/linux/watchdog.h
View file

@ -68,6 +68,7 @@ struct watchdog_device;
* @start: The routine for starting the watchdog device.
* @stop: The routine for stopping the 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.
*
* The watchdog_ops structure contains a list of low-level operations
* that control a watchdog device. It also contains the module that owns
@ -81,12 +82,14 @@ struct watchdog_ops {
int (*stop)(struct watchdog_device *);
/* optional operations */
int (*ping)(struct watchdog_device *);
unsigned int (*status)(struct watchdog_device *);
};
/** struct watchdog_device - The structure that defines a watchdog device
*
* @info: Pointer to a watchdog_info structure.
* @ops: Pointer to the list of watchdog operations.
* @bootstatus: Status of the watchdog device at boot.
* @driver-data:Pointer to the drivers private data.
* @status: Field that contains the devices internal status bits.
*
@ -99,6 +102,7 @@ struct watchdog_ops {
struct watchdog_device {
const struct watchdog_info *info;
const struct watchdog_ops *ops;
unsigned int bootstatus;
void *driver_data;
unsigned long status;
/* Bit numbers for status flags */