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Commit 2fa03560 authored by Wim Van Sebroeck's avatar Wim Van Sebroeck
Browse files

watchdog: WatchDog Timer Driver Core - Add basic ioctl functionality 



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: default avatarAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarWolfram Sang <w.sang@pengutronix.de>
parent 43316044

Documentation/watchdog/watchdog-kernel-api.txt

+6 −0
Original line number Diff line number Diff line
@@ -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:

drivers/watchdog/watchdog_dev.c

+32 −0
Original line number Diff line number Diff line
@@ -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,

};

include/linux/watchdog.h

+4 −0
Original line number Diff line number Diff line
@@ -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 */