Re: [RFC PATCH] watchdog: ep93xx: Use the WatchDog Timer Driver Core.

[Mika Westerberg]

On Mon, Aug 01, 2011 at 01:57:24PM -0700, H Hartley Sweeten wrote:
> Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
> Cc: Wim Van Sebroeck <wim@xxxxxxxxx> (maintainer:WATCHDOG DEVICE D...)

Nice. I'll try to test the patch later today.

I have few minor comments, see below.

> 
> ---
> 
> diff --git a/drivers/watchdog/ep93xx_wdt.c b/drivers/watchdog/ep93xx_wdt.c
> index 726b7df..bb97351 100644
> --- a/drivers/watchdog/ep93xx_wdt.c
> +++ b/drivers/watchdog/ep93xx_wdt.c
> @@ -24,11 +24,9 @@
>   */
>  
>  #include <linux/module.h>
> -#include <linux/fs.h>
>  #include <linux/miscdevice.h>

Is the above header still needed?

>  #include <linux/watchdog.h>
>  #include <linux/timer.h>
> -#include <linux/uaccess.h>
>  #include <linux/io.h>
>  #include <mach/hardware.h>
>  
> @@ -39,15 +37,17 @@
>  #define WDT_TIMEOUT 30
>  
>  static int nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, int, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
> +
>  static int timeout = WDT_TIMEOUT;
> +module_param(timeout, int, 0);
> +MODULE_PARM_DESC(timeout,
> +	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
> +				__MODULE_STRING(WDT_TIMEOUT) ")");
>  
>  static struct timer_list timer;
>  static unsigned long next_heartbeat;
> -static unsigned long wdt_status;
> -static unsigned long boot_status;
> -
> -#define WDT_IN_USE		0
> -#define WDT_OK_TO_CLOSE		1
>  
>  #define EP93XX_WDT_REG(x)	(EP93XX_WATCHDOG_BASE + (x))
>  #define EP93XX_WDT_WATCHDOG	EP93XX_WDT_REG(0x00)
> @@ -71,130 +71,46 @@ static inline void wdt_ping(void)
>  	__raw_writew(0x5555, EP93XX_WDT_WATCHDOG);
>  }
>  
> -static void wdt_startup(void)
> +static int void ep93xx_wdt_start(struct watchdog_device *wdd)
              ^^^^
extra 'void' above

>  {
> -	next_heartbeat = jiffies + (timeout * HZ);
> +	next_heartbeat = jiffies + (wdd->timeout * HZ);
>  
>  	wdt_enable();
>  	mod_timer(&timer, jiffies + WDT_INTERVAL);
> +	return 0;
>  }
>  
> -static void wdt_shutdown(void)
> +static int ep93xx_wdt_stop(struct watchdog_device *wdd)
>  {
>  	del_timer_sync(&timer);
>  	wdt_disable();
> +	return 0;
>  }
>  
> -static void wdt_keepalive(void)
> +static int ep93xx_wdt_keepalive(struct watchdog_device *wdd)
>  {
>  	/* user land ping */
> -	next_heartbeat = jiffies + (timeout * HZ);
> -}
> -
> -static int ep93xx_wdt_open(struct inode *inode, struct file *file)
> -{
> -	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
> -		return -EBUSY;
> -
> -	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
> -
> -	wdt_startup();
> -
> -	return nonseekable_open(inode, file);
> -}
> -
> -static ssize_t
> -ep93xx_wdt_write(struct file *file, const char __user *data, size_t len,
> -		 loff_t *ppos)
> -{
> -	if (len) {
> -		if (!nowayout) {
> -			size_t i;
> -
> -			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
> -
> -			for (i = 0; i != len; i++) {
> -				char c;
> -
> -				if (get_user(c, data + i))
> -					return -EFAULT;
> -
> -				if (c == 'V')
> -					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
> -				else
> -					clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
> -			}
> -		}
> -		wdt_keepalive();
> -	}
> -
> -	return len;
> +	next_heartbeat = jiffies + (wdd->timeout * HZ);
> +	return 0;
>  }
>  
> -static const struct watchdog_info ident = {
> -	.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE,
> -	.identity = "EP93xx Watchdog",
> +static const struct watchdog_info ep93xx_wdt_ident = {
> +	.options	= WDIOF_CARDRESET | WDIOF_MAGICCLOSE,
> +	.identity	= "EP93xx Watchdog",
>  };
>  
> -static long ep93xx_wdt_ioctl(struct file *file,
> -					unsigned int cmd, unsigned long arg)
> -{
> -	int ret = -ENOTTY;
> -
> -	switch (cmd) {
> -	case WDIOC_GETSUPPORT:
> -		ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
> -				sizeof(ident)) ? -EFAULT : 0;
> -		break;
> -
> -	case WDIOC_GETSTATUS:
> -		ret = put_user(0, (int __user *)arg);
> -		break;
> -
> -	case WDIOC_GETBOOTSTATUS:
> -		ret = put_user(boot_status, (int __user *)arg);
> -		break;
> -
> -	case WDIOC_KEEPALIVE:
> -		wdt_keepalive();
> -		ret = 0;
> -		break;
> -
> -	case WDIOC_GETTIMEOUT:
> -		/* actually, it is 0.250 seconds.... */
> -		ret = put_user(1, (int __user *)arg);
> -		break;
> -	}
> -	return ret;
> -}
> -
> -static int ep93xx_wdt_release(struct inode *inode, struct file *file)
> -{
> -	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
> -		wdt_shutdown();
> -	else
> -		printk(KERN_CRIT PFX
> -			"Device closed unexpectedly - timer will not stop\n");
> -
> -	clear_bit(WDT_IN_USE, &wdt_status);
> -	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
> -
> -	return 0;
> -}
> -
> -static const struct file_operations ep93xx_wdt_fops = {
> +static const struct watchdog_ops ep93xx_wdt_ops = {
>  	.owner		= THIS_MODULE,
> -	.write		= ep93xx_wdt_write,
> -	.unlocked_ioctl	= ep93xx_wdt_ioctl,
> -	.open		= ep93xx_wdt_open,
> -	.release	= ep93xx_wdt_release,
> -	.llseek		= no_llseek,
> +	.start		= ep93xx_wdt_start,
> +	.stop		= ep93xx_wdt_stop,
> +	.ping		= ep93xx_wdt_keepalive,
>  };
>  
> -static struct miscdevice ep93xx_wdt_miscdev = {
> -	.minor		= WATCHDOG_MINOR,
> -	.name		= "watchdog",
> -	.fops		= &ep93xx_wdt_fops,
> +static struct watchdog_device ep93xx_wdd = {
> +	.info		= &ep93xx_wdt_ident,
> +	.ops		= &ep93xx_wdt_ops,
> +	.min_timeout	= 1,
> +	.max_timeout	= 3600,
>  };
>  
>  static void ep93xx_timer_ping(unsigned long data)
> @@ -210,43 +126,31 @@ static int __init ep93xx_wdt_init(void)
>  {
>  	int err;
>  
> -	err = misc_register(&ep93xx_wdt_miscdev);
> +	ep93xx_wdd.bootstatus = readl(EP93XX_WDT_WATCHDOG);
> +	ep93xx_wdd.timeout = timeout;

Should you check that the given timeout is in valid range here, like it is
done in the original driver?

> +
> +	err = watchdog_register_device(&ep93xx_wdd);
> +	if (err)
> +		return err;
>  
> -	boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;
> +	setup_timer(&timer, ep93xx_timer_ping, 1);
>  
>  	printk(KERN_INFO PFX "EP93XX watchdog, driver version "
>  		WDT_VERSION "%s\n",
> -		(__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08)
> +		(ep93xx_wdd.bootstatus & 0x08)
>  		? " (nCS1 disable detected)" : "");
>  
> -	if (timeout < 1 || timeout > 3600) {
> -		timeout = WDT_TIMEOUT;
> -		printk(KERN_INFO PFX
> -			"timeout value must be 1<=x<=3600, using %d\n",
> -			timeout);
> -	}
> -
> -	setup_timer(&timer, ep93xx_timer_ping, 1);
> -	return err;
> +	return 0;
>  }
> +module_init(ep93xx_wdt_init);
>  
>  static void __exit ep93xx_wdt_exit(void)
>  {
> -	wdt_shutdown();
> -	misc_deregister(&ep93xx_wdt_miscdev);
> +	wdt_shutdown(&ep93xx_wdd);

ep93xx_wdt_stop(&ep93xx_wdd);

> +	watchdog_unregister_device(&ep93xx_wdd);
>  }
> -
> -module_init(ep93xx_wdt_init);
>  module_exit(ep93xx_wdt_exit);
>  
> -module_param(nowayout, int, 0);
> -MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
> -
> -module_param(timeout, int, 0);
> -MODULE_PARM_DESC(timeout,
> -	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
> -				__MODULE_STRING(WDT_TIMEOUT) ")");
> -
>  MODULE_AUTHOR("Ray Lehtiniemi <rayl@xxxxxxxx>,"
>  		"Alessandro Zummo <a.zummo@xxxxxxxxxxxx>");
>  MODULE_DESCRIPTION("EP93xx Watchdog");
> --
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