Re: [PATCH v2] watchdog: imx2_wdt: convert to watchdog core api

[Anatolij Gustschin <agust@denx.de>]

On Fri, 11 Apr 2014 08:57:14 +0200
Anatolij Gustschin <agust@denx.de> wrote:

> Convert the imx2_wdt driver to the new watchdog core api.
> 
> Signed-off-by: Anatolij Gustschin <agust@denx.de>
> Cc: Wolfram Sang <wsa@the-dreams.de>
> Cc: Wim Van Sebroeck <wim@iguana.be>

Ping. Will this patch be queued for next?

Thanks,

Anatolij

> ---
> NOTE: This patch applies on top of the imx2_wdt regmap-mmio support
> patch series http://comments.gmane.org/gmane.linux.kernel/1677735
> 
> Changes since first version:
>  - simplify return in imx2_wdt_is_running()
>  - fix "WARNING: quoted string split across lines"
> 
>  drivers/watchdog/Kconfig    |    1 +
>  drivers/watchdog/imx2_wdt.c |  292 ++++++++++++++++++-------------------------
>  2 files changed, 123 insertions(+), 170 deletions(-)
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index f2a15f4..5e78c77c 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -379,6 +379,7 @@ config IMX2_WDT
>  	tristate "IMX2+ Watchdog"
>  	depends on ARCH_MXC
>  	select REGMAP_MMIO
> +	select WATCHDOG_CORE
>  	help
>  	  This is the driver for the hardware watchdog
>  	  on the Freescale IMX2 and later processors.
> diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
> index 76fa724..9d4874f 100644
> --- a/drivers/watchdog/imx2_wdt.c
> +++ b/drivers/watchdog/imx2_wdt.c
> @@ -22,18 +22,15 @@
>   */
>  
>  #include <linux/clk.h>
> -#include <linux/fs.h>
>  #include <linux/init.h>
>  #include <linux/io.h>
>  #include <linux/jiffies.h>
>  #include <linux/kernel.h>
> -#include <linux/miscdevice.h>
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/platform_device.h>
>  #include <linux/regmap.h>
>  #include <linux/timer.h>
> -#include <linux/uaccess.h>
>  #include <linux/watchdog.h>
>  
>  #define DRIVER_NAME "imx2-wdt"
> @@ -56,19 +53,12 @@
>  
>  #define WDOG_SEC_TO_COUNT(s)	((s * 2 - 1) << 8)
>  
> -#define IMX2_WDT_STATUS_OPEN	0
> -#define IMX2_WDT_STATUS_STARTED	1
> -#define IMX2_WDT_EXPECT_CLOSE	2
> -
> -static struct {
> +struct imx2_wdt_device {
>  	struct clk *clk;
>  	struct regmap *regmap;
> -	unsigned timeout;
> -	unsigned long status;
>  	struct timer_list timer;	/* Pings the watchdog when closed */
> -} imx2_wdt;
> -
> -static struct miscdevice imx2_wdt_miscdev;
> +	struct watchdog_device wdog;
> +};
>  
>  static bool nowayout = WATCHDOG_NOWAYOUT;
>  module_param(nowayout, bool, 0);
> @@ -86,11 +76,12 @@ static const struct watchdog_info imx2_wdt_info = {
>  	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
>  };
>  
> -static inline void imx2_wdt_setup(void)
> +static inline void imx2_wdt_setup(struct watchdog_device *wdog)
>  {
> +	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
>  	u32 val;
>  
> -	regmap_read(imx2_wdt.regmap, IMX2_WDT_WCR, &val);
> +	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);
>  
>  	/* Suspend timer in low power mode, write once-only */
>  	val |= IMX2_WDT_WCR_WDZST;
> @@ -101,157 +92,93 @@ static inline void imx2_wdt_setup(void)
>  	/* Keep Watchdog Disabled */
>  	val &= ~IMX2_WDT_WCR_WDE;
>  	/* Set the watchdog's Time-Out value */
> -	val |= WDOG_SEC_TO_COUNT(imx2_wdt.timeout);
> +	val |= WDOG_SEC_TO_COUNT(wdog->timeout);
>  
> -	regmap_write(imx2_wdt.regmap, IMX2_WDT_WCR, val);
> +	regmap_write(wdev->regmap, IMX2_WDT_WCR, val);
>  
>  	/* enable the watchdog */
>  	val |= IMX2_WDT_WCR_WDE;
> -	regmap_write(imx2_wdt.regmap, IMX2_WDT_WCR, val);
> +	regmap_write(wdev->regmap, IMX2_WDT_WCR, val);
>  }
>  
> -static inline void imx2_wdt_ping(void)
> +static inline bool imx2_wdt_is_running(struct imx2_wdt_device *wdev)
>  {
> -	regmap_write(imx2_wdt.regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1);
> -	regmap_write(imx2_wdt.regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2);
> -}
> +	u32 val;
>  
> -static void imx2_wdt_timer_ping(unsigned long arg)
> -{
> -	/* ping it every imx2_wdt.timeout / 2 seconds to prevent reboot */
> -	imx2_wdt_ping();
> -	mod_timer(&imx2_wdt.timer, jiffies + imx2_wdt.timeout * HZ / 2);
> +	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);
> +
> +	return val & IMX2_WDT_WCR_WDE;
>  }
>  
> -static void imx2_wdt_start(void)
> +static int imx2_wdt_ping(struct watchdog_device *wdog)
>  {
> -	if (!test_and_set_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
> -		/* at our first start we enable clock and do initialisations */
> -		clk_prepare_enable(imx2_wdt.clk);
> -
> -		imx2_wdt_setup();
> -	} else	/* delete the timer that pings the watchdog after close */
> -		del_timer_sync(&imx2_wdt.timer);
> +	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
>  
> -	/* Watchdog is enabled - time to reload the timeout value */
> -	imx2_wdt_ping();
> +	regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1);
> +	regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2);
> +	return 0;
>  }
>  
> -static void imx2_wdt_stop(void)
> +static void imx2_wdt_timer_ping(unsigned long arg)
>  {
> -	/* we don't need a clk_disable, it cannot be disabled once started.
> -	 * We use a timer to ping the watchdog while /dev/watchdog is closed */
> -	imx2_wdt_timer_ping(0);
> +	struct watchdog_device *wdog = (struct watchdog_device *)arg;
> +	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
> +
> +	/* ping it every wdog->timeout / 2 seconds to prevent reboot */
> +	imx2_wdt_ping(wdog);
> +	mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2);
>  }
>  
> -static void imx2_wdt_set_timeout(int new_timeout)
> +static int imx2_wdt_set_timeout(struct watchdog_device *wdog,
> +				unsigned int new_timeout)
>  {
> -	regmap_update_bits(imx2_wdt.regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT,
> +	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
> +
> +	regmap_update_bits(wdev->regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT,
>  			   WDOG_SEC_TO_COUNT(new_timeout));
> +	return 0;
>  }
>  
> -static int imx2_wdt_open(struct inode *inode, struct file *file)
> +static int imx2_wdt_start(struct watchdog_device *wdog)
>  {
> -	if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status))
> -		return -EBUSY;
> +	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
>  
> -	imx2_wdt_start();
> -	return nonseekable_open(inode, file);
> +	if (imx2_wdt_is_running(wdev)) {
> +		/* delete the timer that pings the watchdog after close */
> +		del_timer_sync(&wdev->timer);
> +		imx2_wdt_set_timeout(wdog, wdog->timeout);
> +	} else
> +		imx2_wdt_setup(wdog);
> +
> +	return imx2_wdt_ping(wdog);
>  }
>  
> -static int imx2_wdt_close(struct inode *inode, struct file *file)
> +static int imx2_wdt_stop(struct watchdog_device *wdog)
>  {
> -	if (test_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status) && !nowayout)
> -		imx2_wdt_stop();
> -	else {
> -		dev_crit(imx2_wdt_miscdev.parent,
> -			"Unexpected close: Expect reboot!\n");
> -		imx2_wdt_ping();
> -	}
> -
> -	clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
> -	clear_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status);
> +	/*
> +	 * We don't need a clk_disable, it cannot be disabled once started.
> +	 * We use a timer to ping the watchdog while /dev/watchdog is closed
> +	 */
> +	imx2_wdt_timer_ping((unsigned long)wdog);
>  	return 0;
>  }
>  
> -static long imx2_wdt_ioctl(struct file *file, unsigned int cmd,
> -							unsigned long arg)
> +static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
>  {
> -	void __user *argp = (void __user *)arg;
> -	int __user *p = argp;
> -	int new_value;
> -	u32 val;
> +	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
>  
> -	switch (cmd) {
> -	case WDIOC_GETSUPPORT:
> -		return copy_to_user(argp, &imx2_wdt_info,
> -			sizeof(struct watchdog_info)) ? -EFAULT : 0;
> -
> -	case WDIOC_GETSTATUS:
> -		return put_user(0, p);
> -
> -	case WDIOC_GETBOOTSTATUS:
> -		regmap_read(imx2_wdt.regmap, IMX2_WDT_WRSR, &val);
> -		new_value = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;
> -		return put_user(new_value, p);
> -
> -	case WDIOC_KEEPALIVE:
> -		imx2_wdt_ping();
> -		return 0;
> -
> -	case WDIOC_SETTIMEOUT:
> -		if (get_user(new_value, p))
> -			return -EFAULT;
> -		if ((new_value < 1) || (new_value > IMX2_WDT_MAX_TIME))
> -			return -EINVAL;
> -		imx2_wdt_set_timeout(new_value);
> -		imx2_wdt.timeout = new_value;
> -		imx2_wdt_ping();
> -
> -		/* Fallthrough to return current value */
> -	case WDIOC_GETTIMEOUT:
> -		return put_user(imx2_wdt.timeout, p);
> -
> -	default:
> -		return -ENOTTY;
> +	if (imx2_wdt_is_running(wdev)) {
> +		imx2_wdt_set_timeout(wdog, wdog->timeout);
> +		imx2_wdt_timer_ping((unsigned long)wdog);
>  	}
>  }
>  
> -static ssize_t imx2_wdt_write(struct file *file, const char __user *data,
> -						size_t len, loff_t *ppos)
> -{
> -	size_t i;
> -	char c;
> -
> -	if (len == 0)	/* Can we see this even ? */
> -		return 0;
> -
> -	clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
> -	/* scan to see whether or not we got the magic character */
> -	for (i = 0; i != len; i++) {
> -		if (get_user(c, data + i))
> -			return -EFAULT;
> -		if (c == 'V')
> -			set_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
> -	}
> -
> -	imx2_wdt_ping();
> -	return len;
> -}
> -
> -static const struct file_operations imx2_wdt_fops = {
> +static struct watchdog_ops imx2_wdt_ops = {
>  	.owner = THIS_MODULE,
> -	.llseek = no_llseek,
> -	.unlocked_ioctl = imx2_wdt_ioctl,
> -	.open = imx2_wdt_open,
> -	.release = imx2_wdt_close,
> -	.write = imx2_wdt_write,
> -};
> -
> -static struct miscdevice imx2_wdt_miscdev = {
> -	.minor = WATCHDOG_MINOR,
> -	.name = "watchdog",
> -	.fops = &imx2_wdt_fops,
> +	.start = imx2_wdt_start,
> +	.stop = imx2_wdt_stop,
> +	.ping = imx2_wdt_ping,
> +	.set_timeout = imx2_wdt_set_timeout,
>  };
>  
>  static struct regmap_config imx2_wdt_regmap_config = {
> @@ -263,76 +190,101 @@ static struct regmap_config imx2_wdt_regmap_config = {
>  
>  static int __init imx2_wdt_probe(struct platform_device *pdev)
>  {
> +	struct imx2_wdt_device *wdev;
> +	struct watchdog_device *wdog;
>  	struct resource *res;
>  	void __iomem *base;
>  	int ret;
> +	u32 val;
> +
> +	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
> +	if (!wdev)
> +		return -ENOMEM;
>  
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	base = devm_ioremap_resource(&pdev->dev, res);
>  	if (IS_ERR(base))
>  		return PTR_ERR(base);
>  
> -	imx2_wdt.regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
> -						    &imx2_wdt_regmap_config);
> -	if (IS_ERR(imx2_wdt.regmap)) {
> +	wdev->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
> +						 &imx2_wdt_regmap_config);
> +	if (IS_ERR(wdev->regmap)) {
>  		dev_err(&pdev->dev, "regmap init failed\n");
> -		return PTR_ERR(imx2_wdt.regmap);
> +		return PTR_ERR(wdev->regmap);
>  	}
>  
> -	imx2_wdt.clk = devm_clk_get(&pdev->dev, NULL);
> -	if (IS_ERR(imx2_wdt.clk)) {
> +	wdev->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(wdev->clk)) {
>  		dev_err(&pdev->dev, "can't get Watchdog clock\n");
> -		return PTR_ERR(imx2_wdt.clk);
> +		return PTR_ERR(wdev->clk);
>  	}
>  
> -	imx2_wdt.timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
> -	if (imx2_wdt.timeout != timeout)
> -		dev_warn(&pdev->dev, "Initial timeout out of range! "
> -			"Clamped from %u to %u\n", timeout, imx2_wdt.timeout);
> +	wdog			= &wdev->wdog;
> +	wdog->info		= &imx2_wdt_info;
> +	wdog->ops		= &imx2_wdt_ops;
> +	wdog->min_timeout	= 1;
> +	wdog->max_timeout	= IMX2_WDT_MAX_TIME;
>  
> -	setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0);
> +	clk_prepare_enable(wdev->clk);
>  
> -	imx2_wdt_miscdev.parent = &pdev->dev;
> -	ret = misc_register(&imx2_wdt_miscdev);
> -	if (ret)
> -		goto fail;
> +	regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val);
> +	wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;
>  
> -	dev_info(&pdev->dev,
> -		"IMX2+ Watchdog Timer enabled. timeout=%ds (nowayout=%d)\n",
> -						imx2_wdt.timeout, nowayout);
> -	return 0;
> +	wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
> +	if (wdog->timeout != timeout)
> +		dev_warn(&pdev->dev, "Initial timeout out of range! Clamped from %u to %u\n",
> +			 timeout, wdog->timeout);
> +
> +	platform_set_drvdata(pdev, wdog);
> +	watchdog_set_drvdata(wdog, wdev);
> +	watchdog_set_nowayout(wdog, nowayout);
> +	watchdog_init_timeout(wdog, timeout, &pdev->dev);
> +
> +	setup_timer(&wdev->timer, imx2_wdt_timer_ping, (unsigned long)wdog);
>  
> -fail:
> -	imx2_wdt_miscdev.parent = NULL;
> -	return ret;
> +	imx2_wdt_ping_if_active(wdog);
> +
> +	ret = watchdog_register_device(wdog);
> +	if (ret) {
> +		dev_err(&pdev->dev, "cannot register watchdog device\n");
> +		return ret;
> +	}
> +
> +	dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n",
> +		 wdog->timeout, nowayout);
> +
> +	return 0;
>  }
>  
>  static int __exit imx2_wdt_remove(struct platform_device *pdev)
>  {
> -	misc_deregister(&imx2_wdt_miscdev);
> +	struct watchdog_device *wdog = platform_get_drvdata(pdev);
> +	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
>  
> -	if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
> -		del_timer_sync(&imx2_wdt.timer);
> +	watchdog_unregister_device(wdog);
>  
> -		dev_crit(imx2_wdt_miscdev.parent,
> -			"Device removed: Expect reboot!\n");
> +	if (imx2_wdt_is_running(wdev)) {
> +		del_timer_sync(&wdev->timer);
> +		imx2_wdt_ping(wdog);
> +		dev_crit(&pdev->dev, "Device removed: Expect reboot!\n");
>  	}
> -
> -	imx2_wdt_miscdev.parent = NULL;
>  	return 0;
>  }
>  
>  static void imx2_wdt_shutdown(struct platform_device *pdev)
>  {
> -	if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
> -		/* we are running, we need to delete the timer but will give
> -		 * max timeout before reboot will take place */
> -		del_timer_sync(&imx2_wdt.timer);
> -		imx2_wdt_set_timeout(IMX2_WDT_MAX_TIME);
> -		imx2_wdt_ping();
> -
> -		dev_crit(imx2_wdt_miscdev.parent,
> -			"Device shutdown: Expect reboot!\n");
> +	struct watchdog_device *wdog = platform_get_drvdata(pdev);
> +	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
> +
> +	if (imx2_wdt_is_running(wdev)) {
> +		/*
> +		 * We are running, we need to delete the timer but will
> +		 * give max timeout before reboot will take place
> +		 */
> +		del_timer_sync(&wdev->timer);
> +		imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
> +		imx2_wdt_ping(wdog);
> +		dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n");
>  	}
>  }
>