watchdog: pc87413: Rewriting of pc87413_wdt driver to use watchdog subsystem
diff mbox series

Message ID 20190731032204.78951-1-mbalant3@gmail.com
State Superseded
Headers show
Series
  • watchdog: pc87413: Rewriting of pc87413_wdt driver to use watchdog subsystem
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Commit Message

Mark Balantzyan July 31, 2019, 3:22 a.m. UTC
This patch rewrites the pc87413_wdt driver to use the watchdog subsystem. In
doing so, it also addresses a potential race condition owing from the
swc_base_addr variable being used before being set.

Signed-off-by: Mark Balantzyan <mbalant3@gmail.com>

---
 drivers/watchdog/Kconfig       |   1 +
 drivers/watchdog/pc87413_wdt.c | 323 ++++-----------------------------
 2 files changed, 40 insertions(+), 284 deletions(-)

Comments

Guenter Roeck July 31, 2019, 4:43 a.m. UTC | #1
On 7/30/19 8:22 PM, Mark Balantzyan wrote:
> This patch rewrites the pc87413_wdt driver to use the watchdog subsystem. In
> doing so, it also addresses a potential race condition owing from the
> swc_base_addr variable being used before being set.
> 
> Signed-off-by: Mark Balantzyan <mbalant3@gmail.com>
> 
> ---
>   drivers/watchdog/Kconfig       |   1 +
>   drivers/watchdog/pc87413_wdt.c | 323 ++++-----------------------------
>   2 files changed, 40 insertions(+), 284 deletions(-)
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 9af07fd9..84a7326d 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1166,6 +1166,7 @@ config SCx200_WDT
>   
>   config PC87413_WDT
>   	tristate "NS PC87413 watchdog"
> +	select WATCHDOG_CORE
>   	depends on X86
>   	---help---
>   	  This is the driver for the hardware watchdog on the PC87413 chipset
> diff --git a/drivers/watchdog/pc87413_wdt.c b/drivers/watchdog/pc87413_wdt.c
> index 06a892e3..60e3cda6 100644
> --- a/drivers/watchdog/pc87413_wdt.c
> +++ b/drivers/watchdog/pc87413_wdt.c
> @@ -22,15 +22,9 @@
>   
>   #include <linux/module.h>
>   #include <linux/types.h>
> -#include <linux/miscdevice.h>
>   #include <linux/watchdog.h>
>   #include <linux/ioport.h>
>   #include <linux/delay.h>
> -#include <linux/notifier.h>
> -#include <linux/fs.h>
> -#include <linux/reboot.h>
> -#include <linux/init.h>
> -#include <linux/spinlock.h>
>   #include <linux/moduleparam.h>
>   #include <linux/io.h>
>   #include <linux/uaccess.h>
> @@ -60,13 +54,9 @@ static int swc_base_addr = -1;
>   
>   static int timeout = DEFAULT_TIMEOUT;	/* timeout value */
>   static unsigned long timer_enabled;	/* is the timer enabled? */
> -
> -static char expect_close;		/* is the close expected? */
> -
> -static DEFINE_SPINLOCK(io_lock);	/* to guard us from io races */
> -
>   static bool nowayout = WATCHDOG_NOWAYOUT;
>   
> +
>   /* -- Low level function ----------------------------------------*/
>   
>   /* Select pins for Watchdog output */
> @@ -151,13 +141,15 @@ static inline void pc87413_swc_bank3(void)
>   
>   /* Set watchdog timeout to x minutes */
>   
> -static inline void pc87413_programm_wdto(char pc87413_time)
> +static int pc87413_set_timeout(struct watchdog_device *wdd, unsigned int t)
>   {
> -	/* Step 5: Programm WDTO, Twd. */
> -	outb_p(pc87413_time, swc_base_addr + WDTO);
> -#ifdef DEBUG
> -	pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
> -#endif
> +	/* Step 5: Programm watchdog timeout */
> +
> +	if ((t < 1) || ( t > 60))    /* arbitrary upper limit */
> +	return -EINVAL;
> +	
> +	timeout = t;
> +	return 0;
>   }
>   
>   /* Enable WDEN */
> @@ -216,281 +208,61 @@ static inline void pc87413_disable_sw_wd_trg(void)
>   
>   /* -- Higher level functions ------------------------------------*/
>   
> -/* Enable the watchdog */
> +/* Enable/start the watchdog */
>   
> -static void pc87413_enable(void)
> +static int pc87413_start(struct watchdog_device *wdd)
>   {
> -	spin_lock(&io_lock);
> -
>   	pc87413_swc_bank3();
> -	pc87413_programm_wdto(timeout);
> +	pc87413_set_timeout(wdd,timeout);
>   	pc87413_enable_wden();
>   	pc87413_enable_sw_wd_tren();
>   	pc87413_enable_sw_wd_trg();
> -
> -	spin_unlock(&io_lock);
> +	return 0;
>   }
>   
> -/* Disable the watchdog */
> +/* Disable/stop the watchdog */
>   
> -static void pc87413_disable(void)
> +static int pc87413_stop(struct watchdog_device *wdd)
>   {
> -	spin_lock(&io_lock);
> -
>   	pc87413_swc_bank3();
>   	pc87413_disable_sw_wd_tren();
>   	pc87413_disable_sw_wd_trg();
> -	pc87413_programm_wdto(0);
> -
> -	spin_unlock(&io_lock);
> +	pc87413_set_timeout(wdd,0);
> +	return 0;
>   }
>   
> -/* Refresh the watchdog */
> +/* Refresh/keepalive the watchdog */
>   
> -static void pc87413_refresh(void)
> +static int pc87413_keepalive(struct watchdog_device *wdd)
>   {
> -	spin_lock(&io_lock);
> -
>   	pc87413_swc_bank3();
>   	pc87413_disable_sw_wd_tren();
>   	pc87413_disable_sw_wd_trg();
> -	pc87413_programm_wdto(timeout);
> +	pc87413_set_timeout(wdd,timeout);
>   	pc87413_enable_wden();
>   	pc87413_enable_sw_wd_tren();
>   	pc87413_enable_sw_wd_trg();
> -
> -	spin_unlock(&io_lock);
> -}
> -
> -/* -- File operations -------------------------------------------*/
> -
> -/**
> - *	pc87413_open:
> - *	@inode: inode of device
> - *	@file: file handle to device
> - *
> - */
> -
> -static int pc87413_open(struct inode *inode, struct file *file)
> -{
> -	/* /dev/watchdog can only be opened once */
> -
> -	if (test_and_set_bit(0, &timer_enabled))
> -		return -EBUSY;
> -
> -	if (nowayout)
> -		__module_get(THIS_MODULE);
> -
> -	/* Reload and activate timer */
> -	pc87413_refresh();
> -
> -	pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
> -
> -	return nonseekable_open(inode, file);
> -}
> -
> -/**
> - *	pc87413_release:
> - *	@inode: inode to board
> - *	@file: file handle to board
> - *
> - *	The watchdog has a configurable API. There is a religious dispute
> - *	between people who want their watchdog to be able to shut down and
> - *	those who want to be sure if the watchdog manager dies the machine
> - *	reboots. In the former case we disable the counters, in the latter
> - *	case you have to open it again very soon.
> - */
> -
> -static int pc87413_release(struct inode *inode, struct file *file)
> -{
> -	/* Shut off the timer. */
> -
> -	if (expect_close == 42) {
> -		pc87413_disable();
> -		pr_info("Watchdog disabled, sleeping again...\n");
> -	} else {
> -		pr_crit("Unexpected close, not stopping watchdog!\n");
> -		pc87413_refresh();
> -	}
> -	clear_bit(0, &timer_enabled);
> -	expect_close = 0;
>   	return 0;
>   }
>   
> -/**
> - *	pc87413_status:
> - *
> - *      return, if the watchdog is enabled (timeout is set...)
> - */
> -
> -
> -static int pc87413_status(void)
> -{
> -	  return 0; /* currently not supported */
> -}
> -
> -/**
> - *	pc87413_write:
> - *	@file: file handle to the watchdog
> - *	@data: data buffer to write
> - *	@len: length in bytes
> - *	@ppos: pointer to the position to write. No seeks allowed
> - *
> - *	A write to a watchdog device is defined as a keepalive signal. Any
> - *	write of data will do, as we we don't define content meaning.
> - */
> -
> -static ssize_t pc87413_write(struct file *file, const char __user *data,
> -			     size_t len, loff_t *ppos)
> -{
> -	/* See if we got the magic character 'V' and reload the timer */
> -	if (len) {
> -		if (!nowayout) {
> -			size_t i;
> -
> -			/* reset expect flag */
> -			expect_close = 0;
> -
> -			/* scan to see whether or not we got the
> -			   magic character */
> -			for (i = 0; i != len; i++) {
> -				char c;
> -				if (get_user(c, data + i))
> -					return -EFAULT;
> -				if (c == 'V')
> -					expect_close = 42;
> -			}
> -		}
> -
> -		/* someone wrote to us, we should reload the timer */
> -		pc87413_refresh();
> -	}
> -	return len;
> -}
> -
> -/**
> - *	pc87413_ioctl:
> - *	@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. We only actually usefully support
> - *	querying capabilities and current status.
> - */
> -
> -static long pc87413_ioctl(struct file *file, unsigned int cmd,
> -						unsigned long arg)
> -{
> -	int new_timeout;
> -
> -	union {
> -		struct watchdog_info __user *ident;
> -		int __user *i;
> -	} uarg;
> -
> -	static const struct watchdog_info ident = {
> -		.options          = WDIOF_KEEPALIVEPING |
> -				    WDIOF_SETTIMEOUT |
> -				    WDIOF_MAGICCLOSE,
> -		.firmware_version = 1,
> -		.identity         = "PC87413(HF/F) watchdog",
> -	};
> -
> -	uarg.i = (int __user *)arg;
> -
> -	switch (cmd) {
> -	case WDIOC_GETSUPPORT:
> -		return copy_to_user(uarg.ident, &ident,
> -					sizeof(ident)) ? -EFAULT : 0;
> -	case WDIOC_GETSTATUS:
> -		return put_user(pc87413_status(), uarg.i);
> -	case WDIOC_GETBOOTSTATUS:
> -		return put_user(0, uarg.i);
> -	case WDIOC_SETOPTIONS:
> -	{
> -		int options, retval = -EINVAL;
> -		if (get_user(options, uarg.i))
> -			return -EFAULT;
> -		if (options & WDIOS_DISABLECARD) {
> -			pc87413_disable();
> -			retval = 0;
> -		}
> -		if (options & WDIOS_ENABLECARD) {
> -			pc87413_enable();
> -			retval = 0;
> -		}
> -		return retval;
> -	}
> -	case WDIOC_KEEPALIVE:
> -		pc87413_refresh();
> -#ifdef DEBUG
> -		pr_info(DPFX "keepalive\n");
> -#endif
> -		return 0;
> -	case WDIOC_SETTIMEOUT:
> -		if (get_user(new_timeout, uarg.i))
> -			return -EFAULT;
> -		/* the API states this is given in secs */
> -		new_timeout /= 60;
> -		if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
> -			return -EINVAL;
> -		timeout = new_timeout;
> -		pc87413_refresh();
> -		/* fall through and return the new timeout... */
> -	case WDIOC_GETTIMEOUT:
> -		new_timeout = timeout * 60;
> -		return put_user(new_timeout, uarg.i);
> -	default:
> -		return -ENOTTY;
> -	}
> -}
> -
> -/* -- Notifier funtions -----------------------------------------*/
> -
> -/**
> - *	notify_sys:
> - *	@this: our notifier block
> - *	@code: the event being reported
> - *	@unused: unused
> - *
> - *	Our notifier is called on system shutdowns. We want to turn the card
> - *	off at reboot otherwise the machine will reboot again during memory
> - *	test or worse yet during the following fsck. This would suck, in fact
> - *	trust me - if it happens it does suck.
> - */
> -
> -static int pc87413_notify_sys(struct notifier_block *this,
> -			      unsigned long code,
> -			      void *unused)
> -{
> -	if (code == SYS_DOWN || code == SYS_HALT)
> -		/* Turn the card off */
> -		pc87413_disable();
> -	return NOTIFY_DONE;
> -}
>   
>   /* -- Module's structures ---------------------------------------*/
>   
> -static const struct file_operations pc87413_fops = {
> -	.owner		= THIS_MODULE,
> -	.llseek		= no_llseek,
> -	.write		= pc87413_write,
> -	.unlocked_ioctl	= pc87413_ioctl,
> -	.open		= pc87413_open,
> -	.release	= pc87413_release,
> -};
>   
> -static struct notifier_block pc87413_notifier = {
> -	.notifier_call  = pc87413_notify_sys,
> +static struct watchdog_ops pc87413wdt_ops = {
> +       	.owner = THIS_MODULE,
> +       	.start = pc87413_start,
> +       	.stop = pc87413_stop,
> +       	.ping = pc87413_keepalive,
> +	.set_timeout = pc87413_set_timeout,

Indentation is off.

>   };
>   
> -static struct miscdevice pc87413_miscdev = {
> -	.minor          = WATCHDOG_MINOR,
> -	.name           = "watchdog",
> -	.fops           = &pc87413_fops,
> +static struct watchdog_device pc87413wdt_wdd = {
> +       	.ops = &pc87413wdt_ops,
> +	.status = WATCHDOG_NOWAYOUT_INIT_STATUS,

Indentation is off.

>   };
>   
> +
>   /* -- Module init functions -------------------------------------*/
>   
>   /**
> @@ -498,7 +270,6 @@ static struct miscdevice pc87413_miscdev = {
>    *
>    *	Set up the WDT watchdog board. All we have to do is grab the
>    *	resources we require and bitch if anyone beat us to them.
> - *	The open() function will actually kick the board off.
>    */
>   
>   static int __init pc87413_init(void)
> @@ -508,20 +279,16 @@ static int __init pc87413_init(void)
>   	pr_info("Version " VERSION " at io 0x%X\n",
>   							WDT_INDEX_IO_PORT);
>   
> +	watchdog_set_nowayout(&pc87413wdt_wdd,nowayout);
> +
Should be called right befor4e registering the watchdog.

>   	if (!request_muxed_region(io, 2, MODNAME))
>   		return -EBUSY;
>   
> -	ret = register_reboot_notifier(&pc87413_notifier);
> -	if (ret != 0)
> -		pr_err("cannot register reboot notifier (err=%d)\n", ret);
> -
> -	ret = misc_register(&pc87413_miscdev);
> +	watchdog_stop_on_reboot(&pc87413wdt_wdd);
> +	ret = watchdog_register_device(&pc87413wdt_wdd);
>   	if (ret != 0) {
> -		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
> -		       WATCHDOG_MINOR, ret);
>   		goto reboot_unreg;
> -	}
> -	pr_info("initialized. timeout=%d min\n", timeout);
> +	}	pr_info("initialized. timeout=%d min\n", timeout);

Really bad formatting.

>   
>   	pc87413_select_wdt_out();
>   	pc87413_enable_swc();
> @@ -530,20 +297,16 @@ static int __init pc87413_init(void)
>   	if (!request_region(swc_base_addr, 0x20, MODNAME)) {
>   		pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
>   		ret = -EBUSY;
> -		goto misc_unreg;
> +		goto watchdog_unreg;
>   	}

The point of the original problem was that the misc device was registered before
this region was requested, which caused the race condition. That problem still
exists = the watchdog is registered, and thus may be opened, before this region
is requested.

>   
> -	pc87413_enable();
> -
>   	release_region(io, 2);
>   	return 0;
> -
> -misc_unreg:
> -	misc_deregister(&pc87413_miscdev);
>   reboot_unreg:
> -	unregister_reboot_notifier(&pc87413_notifier);
>   	release_region(io, 2);
>   	return ret;
> +watchdog_unreg:
> +	watchdog_unregister_device(&pc87413wdt_wdd);

Return value missing. Doesn't the compile complain about that ?

>   }
>   
>   /**
> @@ -558,14 +321,7 @@ reboot_unreg:
>   
>   static void __exit pc87413_exit(void)
>   {
> -	/* Stop the timer before we leave */
> -	if (!nowayout) {
> -		pc87413_disable();
> -		pr_info("Watchdog disabled\n");
> -	}
> -
> -	misc_deregister(&pc87413_miscdev);
> -	unregister_reboot_notifier(&pc87413_notifier);
> +	watchdog_unregister_device(&pc87413wdt_wdd);
>   	release_region(swc_base_addr, 0x20);
>   
>   	pr_info("watchdog component driver removed\n");
> @@ -592,4 +348,3 @@ module_param(nowayout, bool, 0);
>   MODULE_PARM_DESC(nowayout,
>   		"Watchdog cannot be stopped once started (default="
>   				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> -
>
Mark Balantzyan July 31, 2019, 5:06 a.m. UTC | #2
Hi all, Guenter,

Thank you for your email. Unfortunately, on my end, the indentation is
straight and perhaps through protocol transfer there was stray
modification.

I've made the other changes as indicated that I'll submit in a v2 patch 
shortly. Is 'v2' permissible to include in the title in this case? Not 
sure, but this will BE a modification...in that case I should have been 
v-ing my patches since.

No, the compiler did not complain about no 'return ret' as part of the 
label code block. The function does 'return 0;' at the end, by default.

Thanks + regards,
Mark
Guenter Roeck July 31, 2019, 1:18 p.m. UTC | #3
On 7/30/19 10:06 PM, Mark Balantzyan wrote:
> Hi all, Guenter,
> 
> Thank you for your email. Unfortunately, on my end, the indentation is
> straight and perhaps through protocol transfer there was stray
> modification.
> 

checkpatch --strict says:

total: 13 errors, 13 warnings, 4 checks, 439 lines checked

Please fix all those, including the checks, before you resubmit.

Thanks,
Guenter

Patch
diff mbox series

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 9af07fd9..84a7326d 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1166,6 +1166,7 @@  config SCx200_WDT
 
 config PC87413_WDT
 	tristate "NS PC87413 watchdog"
+	select WATCHDOG_CORE
 	depends on X86
 	---help---
 	  This is the driver for the hardware watchdog on the PC87413 chipset
diff --git a/drivers/watchdog/pc87413_wdt.c b/drivers/watchdog/pc87413_wdt.c
index 06a892e3..60e3cda6 100644
--- a/drivers/watchdog/pc87413_wdt.c
+++ b/drivers/watchdog/pc87413_wdt.c
@@ -22,15 +22,9 @@ 
 
 #include <linux/module.h>
 #include <linux/types.h>
-#include <linux/miscdevice.h>
 #include <linux/watchdog.h>
 #include <linux/ioport.h>
 #include <linux/delay.h>
-#include <linux/notifier.h>
-#include <linux/fs.h>
-#include <linux/reboot.h>
-#include <linux/init.h>
-#include <linux/spinlock.h>
 #include <linux/moduleparam.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>
@@ -60,13 +54,9 @@  static int swc_base_addr = -1;
 
 static int timeout = DEFAULT_TIMEOUT;	/* timeout value */
 static unsigned long timer_enabled;	/* is the timer enabled? */
-
-static char expect_close;		/* is the close expected? */
-
-static DEFINE_SPINLOCK(io_lock);	/* to guard us from io races */
-
 static bool nowayout = WATCHDOG_NOWAYOUT;
 
+
 /* -- Low level function ----------------------------------------*/
 
 /* Select pins for Watchdog output */
@@ -151,13 +141,15 @@  static inline void pc87413_swc_bank3(void)
 
 /* Set watchdog timeout to x minutes */
 
-static inline void pc87413_programm_wdto(char pc87413_time)
+static int pc87413_set_timeout(struct watchdog_device *wdd, unsigned int t)
 {
-	/* Step 5: Programm WDTO, Twd. */
-	outb_p(pc87413_time, swc_base_addr + WDTO);
-#ifdef DEBUG
-	pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
-#endif
+	/* Step 5: Programm watchdog timeout */
+
+	if ((t < 1) || ( t > 60))    /* arbitrary upper limit */
+	return -EINVAL;
+	
+	timeout = t;
+	return 0;
 }
 
 /* Enable WDEN */
@@ -216,281 +208,61 @@  static inline void pc87413_disable_sw_wd_trg(void)
 
 /* -- Higher level functions ------------------------------------*/
 
-/* Enable the watchdog */
+/* Enable/start the watchdog */
 
-static void pc87413_enable(void)
+static int pc87413_start(struct watchdog_device *wdd)
 {
-	spin_lock(&io_lock);
-
 	pc87413_swc_bank3();
-	pc87413_programm_wdto(timeout);
+	pc87413_set_timeout(wdd,timeout);
 	pc87413_enable_wden();
 	pc87413_enable_sw_wd_tren();
 	pc87413_enable_sw_wd_trg();
-
-	spin_unlock(&io_lock);
+	return 0;
 }
 
-/* Disable the watchdog */
+/* Disable/stop the watchdog */
 
-static void pc87413_disable(void)
+static int pc87413_stop(struct watchdog_device *wdd)
 {
-	spin_lock(&io_lock);
-
 	pc87413_swc_bank3();
 	pc87413_disable_sw_wd_tren();
 	pc87413_disable_sw_wd_trg();
-	pc87413_programm_wdto(0);
-
-	spin_unlock(&io_lock);
+	pc87413_set_timeout(wdd,0);
+	return 0;
 }
 
-/* Refresh the watchdog */
+/* Refresh/keepalive the watchdog */
 
-static void pc87413_refresh(void)
+static int pc87413_keepalive(struct watchdog_device *wdd)
 {
-	spin_lock(&io_lock);
-
 	pc87413_swc_bank3();
 	pc87413_disable_sw_wd_tren();
 	pc87413_disable_sw_wd_trg();
-	pc87413_programm_wdto(timeout);
+	pc87413_set_timeout(wdd,timeout);
 	pc87413_enable_wden();
 	pc87413_enable_sw_wd_tren();
 	pc87413_enable_sw_wd_trg();
-
-	spin_unlock(&io_lock);
-}
-
-/* -- File operations -------------------------------------------*/
-
-/**
- *	pc87413_open:
- *	@inode: inode of device
- *	@file: file handle to device
- *
- */
-
-static int pc87413_open(struct inode *inode, struct file *file)
-{
-	/* /dev/watchdog can only be opened once */
-
-	if (test_and_set_bit(0, &timer_enabled))
-		return -EBUSY;
-
-	if (nowayout)
-		__module_get(THIS_MODULE);
-
-	/* Reload and activate timer */
-	pc87413_refresh();
-
-	pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
-
-	return nonseekable_open(inode, file);
-}
-
-/**
- *	pc87413_release:
- *	@inode: inode to board
- *	@file: file handle to board
- *
- *	The watchdog has a configurable API. There is a religious dispute
- *	between people who want their watchdog to be able to shut down and
- *	those who want to be sure if the watchdog manager dies the machine
- *	reboots. In the former case we disable the counters, in the latter
- *	case you have to open it again very soon.
- */
-
-static int pc87413_release(struct inode *inode, struct file *file)
-{
-	/* Shut off the timer. */
-
-	if (expect_close == 42) {
-		pc87413_disable();
-		pr_info("Watchdog disabled, sleeping again...\n");
-	} else {
-		pr_crit("Unexpected close, not stopping watchdog!\n");
-		pc87413_refresh();
-	}
-	clear_bit(0, &timer_enabled);
-	expect_close = 0;
 	return 0;
 }
 
-/**
- *	pc87413_status:
- *
- *      return, if the watchdog is enabled (timeout is set...)
- */
-
-
-static int pc87413_status(void)
-{
-	  return 0; /* currently not supported */
-}
-
-/**
- *	pc87413_write:
- *	@file: file handle to the watchdog
- *	@data: data buffer to write
- *	@len: length in bytes
- *	@ppos: pointer to the position to write. No seeks allowed
- *
- *	A write to a watchdog device is defined as a keepalive signal. Any
- *	write of data will do, as we we don't define content meaning.
- */
-
-static ssize_t pc87413_write(struct file *file, const char __user *data,
-			     size_t len, loff_t *ppos)
-{
-	/* See if we got the magic character 'V' and reload the timer */
-	if (len) {
-		if (!nowayout) {
-			size_t i;
-
-			/* reset expect flag */
-			expect_close = 0;
-
-			/* scan to see whether or not we got the
-			   magic character */
-			for (i = 0; i != len; i++) {
-				char c;
-				if (get_user(c, data + i))
-					return -EFAULT;
-				if (c == 'V')
-					expect_close = 42;
-			}
-		}
-
-		/* someone wrote to us, we should reload the timer */
-		pc87413_refresh();
-	}
-	return len;
-}
-
-/**
- *	pc87413_ioctl:
- *	@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. We only actually usefully support
- *	querying capabilities and current status.
- */
-
-static long pc87413_ioctl(struct file *file, unsigned int cmd,
-						unsigned long arg)
-{
-	int new_timeout;
-
-	union {
-		struct watchdog_info __user *ident;
-		int __user *i;
-	} uarg;
-
-	static const struct watchdog_info ident = {
-		.options          = WDIOF_KEEPALIVEPING |
-				    WDIOF_SETTIMEOUT |
-				    WDIOF_MAGICCLOSE,
-		.firmware_version = 1,
-		.identity         = "PC87413(HF/F) watchdog",
-	};
-
-	uarg.i = (int __user *)arg;
-
-	switch (cmd) {
-	case WDIOC_GETSUPPORT:
-		return copy_to_user(uarg.ident, &ident,
-					sizeof(ident)) ? -EFAULT : 0;
-	case WDIOC_GETSTATUS:
-		return put_user(pc87413_status(), uarg.i);
-	case WDIOC_GETBOOTSTATUS:
-		return put_user(0, uarg.i);
-	case WDIOC_SETOPTIONS:
-	{
-		int options, retval = -EINVAL;
-		if (get_user(options, uarg.i))
-			return -EFAULT;
-		if (options & WDIOS_DISABLECARD) {
-			pc87413_disable();
-			retval = 0;
-		}
-		if (options & WDIOS_ENABLECARD) {
-			pc87413_enable();
-			retval = 0;
-		}
-		return retval;
-	}
-	case WDIOC_KEEPALIVE:
-		pc87413_refresh();
-#ifdef DEBUG
-		pr_info(DPFX "keepalive\n");
-#endif
-		return 0;
-	case WDIOC_SETTIMEOUT:
-		if (get_user(new_timeout, uarg.i))
-			return -EFAULT;
-		/* the API states this is given in secs */
-		new_timeout /= 60;
-		if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
-			return -EINVAL;
-		timeout = new_timeout;
-		pc87413_refresh();
-		/* fall through and return the new timeout... */
-	case WDIOC_GETTIMEOUT:
-		new_timeout = timeout * 60;
-		return put_user(new_timeout, uarg.i);
-	default:
-		return -ENOTTY;
-	}
-}
-
-/* -- Notifier funtions -----------------------------------------*/
-
-/**
- *	notify_sys:
- *	@this: our notifier block
- *	@code: the event being reported
- *	@unused: unused
- *
- *	Our notifier is called on system shutdowns. We want to turn the card
- *	off at reboot otherwise the machine will reboot again during memory
- *	test or worse yet during the following fsck. This would suck, in fact
- *	trust me - if it happens it does suck.
- */
-
-static int pc87413_notify_sys(struct notifier_block *this,
-			      unsigned long code,
-			      void *unused)
-{
-	if (code == SYS_DOWN || code == SYS_HALT)
-		/* Turn the card off */
-		pc87413_disable();
-	return NOTIFY_DONE;
-}
 
 /* -- Module's structures ---------------------------------------*/
 
-static const struct file_operations pc87413_fops = {
-	.owner		= THIS_MODULE,
-	.llseek		= no_llseek,
-	.write		= pc87413_write,
-	.unlocked_ioctl	= pc87413_ioctl,
-	.open		= pc87413_open,
-	.release	= pc87413_release,
-};
 
-static struct notifier_block pc87413_notifier = {
-	.notifier_call  = pc87413_notify_sys,
+static struct watchdog_ops pc87413wdt_ops = {
+       	.owner = THIS_MODULE,
+       	.start = pc87413_start,
+       	.stop = pc87413_stop,
+       	.ping = pc87413_keepalive,
+	.set_timeout = pc87413_set_timeout,
 };
 
-static struct miscdevice pc87413_miscdev = {
-	.minor          = WATCHDOG_MINOR,
-	.name           = "watchdog",
-	.fops           = &pc87413_fops,
+static struct watchdog_device pc87413wdt_wdd = {
+       	.ops = &pc87413wdt_ops,
+	.status = WATCHDOG_NOWAYOUT_INIT_STATUS,
 };
 
+
 /* -- Module init functions -------------------------------------*/
 
 /**
@@ -498,7 +270,6 @@  static struct miscdevice pc87413_miscdev = {
  *
  *	Set up the WDT watchdog board. All we have to do is grab the
  *	resources we require and bitch if anyone beat us to them.
- *	The open() function will actually kick the board off.
  */
 
 static int __init pc87413_init(void)
@@ -508,20 +279,16 @@  static int __init pc87413_init(void)
 	pr_info("Version " VERSION " at io 0x%X\n",
 							WDT_INDEX_IO_PORT);
 
+	watchdog_set_nowayout(&pc87413wdt_wdd,nowayout);
+
 	if (!request_muxed_region(io, 2, MODNAME))
 		return -EBUSY;
 
-	ret = register_reboot_notifier(&pc87413_notifier);
-	if (ret != 0)
-		pr_err("cannot register reboot notifier (err=%d)\n", ret);
-
-	ret = misc_register(&pc87413_miscdev);
+	watchdog_stop_on_reboot(&pc87413wdt_wdd);
+	ret = watchdog_register_device(&pc87413wdt_wdd);
 	if (ret != 0) {
-		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
-		       WATCHDOG_MINOR, ret);
 		goto reboot_unreg;
-	}
-	pr_info("initialized. timeout=%d min\n", timeout);
+	}	pr_info("initialized. timeout=%d min\n", timeout);
 
 	pc87413_select_wdt_out();
 	pc87413_enable_swc();
@@ -530,20 +297,16 @@  static int __init pc87413_init(void)
 	if (!request_region(swc_base_addr, 0x20, MODNAME)) {
 		pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
 		ret = -EBUSY;
-		goto misc_unreg;
+		goto watchdog_unreg;
 	}
 
-	pc87413_enable();
-
 	release_region(io, 2);
 	return 0;
-
-misc_unreg:
-	misc_deregister(&pc87413_miscdev);
 reboot_unreg:
-	unregister_reboot_notifier(&pc87413_notifier);
 	release_region(io, 2);
 	return ret;
+watchdog_unreg:
+	watchdog_unregister_device(&pc87413wdt_wdd);
 }
 
 /**
@@ -558,14 +321,7 @@  reboot_unreg:
 
 static void __exit pc87413_exit(void)
 {
-	/* Stop the timer before we leave */
-	if (!nowayout) {
-		pc87413_disable();
-		pr_info("Watchdog disabled\n");
-	}
-
-	misc_deregister(&pc87413_miscdev);
-	unregister_reboot_notifier(&pc87413_notifier);
+	watchdog_unregister_device(&pc87413wdt_wdd);
 	release_region(swc_base_addr, 0x20);
 
 	pr_info("watchdog component driver removed\n");
@@ -592,4 +348,3 @@  module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout,
 		"Watchdog cannot be stopped once started (default="
 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
-