Re: [PATCH 4/4] MIPS: bmips: Convert bcm63xx_wdt to use WATCHDOG_CORE

[Guenter Roeck]

On 11/21/2015 11:05 AM, Simon Arlott wrote:
> Convert bcm63xx_wdt to use WATCHDOG_CORE and add a device tree binding.
>
> Adds support for the time left value and provides a more effective
> interrupt handler based on the watchdog warning interrupt behaviour.
>
> This removes the unnecessary software countdown timer and replaces the
> use of bcm63xx_timer with a normal interrupt when not using mach-bcm63xx.

Hi Simon,

this is really doing a bit too much in a single patch.
Conversion to the watchdog infrastructure should probably be
the first step, followed by further optimizations and improvements.

In general, it would be great if we can avoid #ifdef in the code.
Maybe there is some other means to determine if one code path
needs to be taken or another. The driver may be part of a
multi-platform image, and #ifdefs in the code make that all
but impossible. Besides, it makes the code really hard to read
and understand.

We have some infrastructure changes in the works which will move
the need for soft-timers from individual drivers into the watchdog core.
Would this possibly be helpful here ? The timer-driven watchdog ping
seems to accomplish pretty much the same.

Thanks,
Guenter

> Signed-off-by: Simon Arlott <simon@xxxxxxxxxxx>
> ---
>   arch/mips/bcm63xx/prom.c                          |   1 +
>   arch/mips/bcm63xx/setup.c                         |   1 +
>   arch/mips/include/asm/mach-bcm63xx/bcm63xx_regs.h |  22 --
>   drivers/watchdog/Kconfig                          |   4 +-
>   drivers/watchdog/bcm63xx_wdt.c                    | 420 +++++++++++-----------
>   include/linux/bcm63xx_wdt.h                       |  22 ++
>   6 files changed, 244 insertions(+), 226 deletions(-)
>   create mode 100644 include/linux/bcm63xx_wdt.h
>
> diff --git a/arch/mips/bcm63xx/prom.c b/arch/mips/bcm63xx/prom.c
> index 7019e29..ba8b354 100644
> --- a/arch/mips/bcm63xx/prom.c
> +++ b/arch/mips/bcm63xx/prom.c
> @@ -17,6 +17,7 @@
>   #include <bcm63xx_cpu.h>
>   #include <bcm63xx_io.h>
>   #include <bcm63xx_regs.h>
> +#include <linux/bcm63xx_wdt.h>
>
>   void __init prom_init(void)
>   {
> diff --git a/arch/mips/bcm63xx/setup.c b/arch/mips/bcm63xx/setup.c
> index 240fb4f..6abf364 100644
> --- a/arch/mips/bcm63xx/setup.c
> +++ b/arch/mips/bcm63xx/setup.c
> @@ -21,6 +21,7 @@
>   #include <bcm63xx_regs.h>
>   #include <bcm63xx_io.h>
>   #include <bcm63xx_gpio.h>
> +#include <linux/bcm63xx_wdt.h>
>
>   void bcm63xx_machine_halt(void)
>   {
> diff --git a/arch/mips/include/asm/mach-bcm63xx/bcm63xx_regs.h b/arch/mips/include/asm/mach-bcm63xx/bcm63xx_regs.h
> index 5035f09..16a745b 100644
> --- a/arch/mips/include/asm/mach-bcm63xx/bcm63xx_regs.h
> +++ b/arch/mips/include/asm/mach-bcm63xx/bcm63xx_regs.h
> @@ -441,28 +441,6 @@
>
>
>   /*************************************************************************
> - * _REG relative to RSET_WDT
> - *************************************************************************/
> -
> -/* Watchdog default count register */
> -#define WDT_DEFVAL_REG			0x0
> -
> -/* Watchdog control register */
> -#define WDT_CTL_REG			0x4
> -
> -/* Watchdog control register constants */
> -#define WDT_START_1			(0xff00)
> -#define WDT_START_2			(0x00ff)
> -#define WDT_STOP_1			(0xee00)
> -#define WDT_STOP_2			(0x00ee)
> -
> -/* Watchdog reset length register */
> -#define WDT_RSTLEN_REG			0x8
> -
> -/* Watchdog soft reset register (BCM6328 only) */
> -#define WDT_SOFTRESET_REG		0xc
> -
> -/*************************************************************************
>    * _REG relative to RSET_GPIO
>    *************************************************************************/
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 7a8a6c6..0c50add 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1272,7 +1272,9 @@ config OCTEON_WDT
>
>   config BCM63XX_WDT
>   	tristate "Broadcom BCM63xx hardware watchdog"
> -	depends on BCM63XX
> +	depends on BCM63XX || BMIPS_GENERIC
> +	select WATCHDOG_CORE
> +	select BCM6345_L2_TIMER_IRQ if BMIPS_GENERIC
>   	help
>   	  Watchdog driver for the built in watchdog hardware in Broadcom
>   	  BCM63xx SoC.
> diff --git a/drivers/watchdog/bcm63xx_wdt.c b/drivers/watchdog/bcm63xx_wdt.c
> index ab26fd9..fff92d0 100644
> --- a/drivers/watchdog/bcm63xx_wdt.c
> +++ b/drivers/watchdog/bcm63xx_wdt.c
> @@ -3,6 +3,7 @@
>    *
>    *  Copyright (C) 2007, Miguel Gaio <miguel.gaio@xxxxxxxxx>
>    *  Copyright (C) 2008, Florian Fainelli <florian@xxxxxxxxxxx>
> + *  Copyright 2015 Simon Arlott
>    *
>    *  This program is free software; you can redistribute it and/or
>    *  modify it under the terms of the GNU General Public License
> @@ -12,235 +13,165 @@
>
>   #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
> -#include <linux/bitops.h>
> +#include <linux/bcm63xx_wdt.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
>   #include <linux/errno.h>
> -#include <linux/fs.h>
> +#include <linux/interrupt.h>
>   #include <linux/io.h>
>   #include <linux/kernel.h>
> -#include <linux/miscdevice.h>
>   #include <linux/module.h>
>   #include <linux/moduleparam.h>
> +#include <linux/platform_device.h>
> +#include <linux/resource.h>
> +#include <linux/spinlock.h>
>   #include <linux/types.h>
> -#include <linux/uaccess.h>
>   #include <linux/watchdog.h>
> -#include <linux/timer.h>
> -#include <linux/jiffies.h>
> -#include <linux/interrupt.h>
> -#include <linux/ptrace.h>
> -#include <linux/resource.h>
> -#include <linux/platform_device.h>
>
> -#include <bcm63xx_cpu.h>
> -#include <bcm63xx_io.h>
> -#include <bcm63xx_regs.h>
> -#include <bcm63xx_timer.h>
> +#ifdef CONFIG_BCM63XX
> +# include <bcm63xx_regs.h>
> +# include <bcm63xx_timer.h>
> +#endif
>
>   #define PFX KBUILD_MODNAME
>
> -#define WDT_HZ		50000000 /* Fclk */
> -#define WDT_DEFAULT_TIME	30      /* seconds */
> -#define WDT_MAX_TIME		256     /* seconds */
> -
> -static struct {
> -	void __iomem *regs;
> -	struct timer_list timer;
> -	unsigned long inuse;
> -	atomic_t ticks;
> -} bcm63xx_wdt_device;
> -
> -static int expect_close;
> -
> -static int wdt_time = WDT_DEFAULT_TIME;
>   static bool nowayout = WATCHDOG_NOWAYOUT;
>   module_param(nowayout, bool, 0);
>   MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
>   	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
>
> -/* HW functions */
> -static void bcm63xx_wdt_hw_start(void)
> -{
> -	bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
> -	bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
> -	bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
> -}
> -
> -static void bcm63xx_wdt_hw_stop(void)
> -{
> -	bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
> -	bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
> -}
> -
> -static void bcm63xx_wdt_isr(void *data)
> -{
> -	struct pt_regs *regs = get_irq_regs();
> -
> -	die(PFX " fire", regs);
> -}
> -
> -static void bcm63xx_timer_tick(unsigned long unused)
> -{
> -	if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
> -		bcm63xx_wdt_hw_start();
> -		mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
> -	} else
> -		pr_crit("watchdog will restart system\n");
> -}
> -
> -static void bcm63xx_wdt_pet(void)
> -{
> -	atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
> -}
> -
> -static void bcm63xx_wdt_start(void)
> -{
> -	bcm63xx_wdt_pet();
> -	bcm63xx_timer_tick(0);
> -}
> +struct bcm63xx_wdt_hw {
> +	raw_spinlock_t lock;
> +	void __iomem *base;
> +	struct clk *clk;
> +	u32 clock_hz;
> +	int irq;
> +	bool running;
> +};
>
> -static void bcm63xx_wdt_pause(void)
> +static int bcm63xx_wdt_start(struct watchdog_device *wdd)
>   {
> -	del_timer_sync(&bcm63xx_wdt_device.timer);
> -	bcm63xx_wdt_hw_stop();
> +	struct bcm63xx_wdt_hw *hw = watchdog_get_drvdata(wdd);
> +	unsigned long flags;
> +
> +	raw_spin_lock_irqsave(&hw->lock, flags);
> +	__raw_writel(wdd->timeout * hw->clock_hz, hw->base + WDT_DEFVAL_REG);
> +	__raw_writel(WDT_START_1, hw->base + WDT_CTL_REG);
> +	__raw_writel(WDT_START_2, hw->base + WDT_CTL_REG);
> +	hw->running = true;
> +	raw_spin_unlock_irqrestore(&hw->lock, flags);
> +	return 0;
>   }
>
> -static int bcm63xx_wdt_settimeout(int new_time)
> +static int bcm63xx_wdt_stop(struct watchdog_device *wdd)
>   {
> -	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
> -		return -EINVAL;
> -
> -	wdt_time = new_time;
> -
> +	struct bcm63xx_wdt_hw *hw = watchdog_get_drvdata(wdd);
> +	unsigned long flags;
> +
> +	raw_spin_lock_irqsave(&hw->lock, flags);
> +	__raw_writel(WDT_STOP_1, hw->base + WDT_CTL_REG);
> +	__raw_writel(WDT_STOP_2, hw->base + WDT_CTL_REG);
> +	hw->running = false;
> +	raw_spin_unlock_irqrestore(&hw->lock, flags);
>   	return 0;
>   }
>
> -static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
> +static unsigned int bcm63xx_wdt_get_timeleft(struct watchdog_device *wdd)
>   {
> -	if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
> -		return -EBUSY;
> -
> -	bcm63xx_wdt_start();
> -	return nonseekable_open(inode, file);
> +	struct bcm63xx_wdt_hw *hw = watchdog_get_drvdata(wdd);
> +	unsigned long flags;
> +	u32 val;
> +
> +	raw_spin_lock_irqsave(&hw->lock, flags);
> +	val = __raw_readl(hw->base + WDT_CTL_REG);
> +	val /= hw->clock_hz;
> +	raw_spin_unlock_irqrestore(&hw->lock, flags);
> +	return val;
>   }
>
> -static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
> +static int bcm63xx_wdt_set_timeout(struct watchdog_device *wdd,
> +	unsigned int timeout)
>   {
> -	if (expect_close == 42)
> -		bcm63xx_wdt_pause();
> -	else {
> -		pr_crit("Unexpected close, not stopping watchdog!\n");
> -		bcm63xx_wdt_start();
> -	}
> -	clear_bit(0, &bcm63xx_wdt_device.inuse);
> -	expect_close = 0;
> -	return 0;
> +	wdd->timeout = timeout;
> +	return bcm63xx_wdt_start(wdd);
>   }
>
> -static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
> -				size_t len, loff_t *ppos)
> +/* The watchdog interrupt occurs when half the timeout is remaining */
> +#ifdef CONFIG_BCM63XX
> +static void bcm63xx_wdt_interrupt(void *data)
> +#else
> +static irqreturn_t bcm63xx_wdt_interrupt(int irq, void *data)
> +#endif
>   {
> -	if (len) {
> -		if (!nowayout) {
> -			size_t i;
> -
> -			/* In case it was set long ago */
> -			expect_close = 0;
> -
> -			for (i = 0; i != len; i++) {
> -				char c;
> -				if (get_user(c, data + i))
> -					return -EFAULT;
> -				if (c == 'V')
> -					expect_close = 42;
> -			}
> +	struct watchdog_device *wdd = data;
> +	struct bcm63xx_wdt_hw *hw = watchdog_get_drvdata(wdd);
> +	unsigned long flags;
> +
> +	raw_spin_lock_irqsave(&hw->lock, flags);
> +	if (!hw->running) {
> +		/* Oops */
> +		__raw_writel(WDT_STOP_1, hw->base + WDT_CTL_REG);
> +		__raw_writel(WDT_STOP_2, hw->base + WDT_CTL_REG);
> +	} else {
> +		u32 timeleft = __raw_readl(hw->base + WDT_CTL_REG);
> +		u32 ms;
> +
> +		if (timeleft >= 2) {
> +			/* The only way to stop this interrupt without masking
> +			 * the whole timer interrupt or disrupting the intended
> +			 * behaviour of the watchdog is to restart the watchdog
> +			 * with the remaining time value so that the interrupt
> +			 * occurs again at 1/4th, 1/8th, etc. of the timeout
> +			 * until we reboot.
> +			 *
> +			 * This is done with a lock held in case userspace is
> +			 * restarting the watchdog on another CPU.
> +			 */
> +			__raw_writel(timeleft, hw->base + WDT_DEFVAL_REG);
> +			__raw_writel(WDT_START_1, hw->base + WDT_CTL_REG);
> +			__raw_writel(WDT_START_2, hw->base + WDT_CTL_REG);
> +		} else {
> +			/* The watchdog cannot be started with a time of less
> +			 * than 2 ticks (it won't fire).
> +			 */
> +			die(PFX ": watchdog timer expired\n", get_irq_regs());
>   		}
> -		bcm63xx_wdt_pet();
> -	}
> -	return len;
> -}
> -
> -static struct watchdog_info bcm63xx_wdt_info = {
> -	.identity       = PFX,
> -	.options        = WDIOF_SETTIMEOUT |
> -				WDIOF_KEEPALIVEPING |
> -				WDIOF_MAGICCLOSE,
> -};
> -
> -
> -static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
> -				unsigned long arg)
> -{
> -	void __user *argp = (void __user *)arg;
> -	int __user *p = argp;
> -	int new_value, retval = -EINVAL;
> -
> -	switch (cmd) {
> -	case WDIOC_GETSUPPORT:
> -		return copy_to_user(argp, &bcm63xx_wdt_info,
> -			sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
> -
> -	case WDIOC_GETSTATUS:
> -	case WDIOC_GETBOOTSTATUS:
> -		return put_user(0, p);
> -
> -	case WDIOC_SETOPTIONS:
> -		if (get_user(new_value, p))
> -			return -EFAULT;
> -
> -		if (new_value & WDIOS_DISABLECARD) {
> -			bcm63xx_wdt_pause();
> -			retval = 0;
> -		}
> -		if (new_value & WDIOS_ENABLECARD) {
> -			bcm63xx_wdt_start();
> -			retval = 0;
> -		}
> -
> -		return retval;
> -
> -	case WDIOC_KEEPALIVE:
> -		bcm63xx_wdt_pet();
> -		return 0;
> -
> -	case WDIOC_SETTIMEOUT:
> -		if (get_user(new_value, p))
> -			return -EFAULT;
> -
> -		if (bcm63xx_wdt_settimeout(new_value))
> -			return -EINVAL;
> -
> -		bcm63xx_wdt_pet();
> -
> -	case WDIOC_GETTIMEOUT:
> -		return put_user(wdt_time, p);
> -
> -	default:
> -		return -ENOTTY;
>
> +		ms = timeleft / (hw->clock_hz / 1000);
> +		dev_alert(wdd->dev, "warning timer fired, reboot in %ums", ms);
>   	}
> +	raw_spin_unlock_irqrestore(&hw->lock, flags);
> +#ifndef CONFIG_BCM63XX
> +	return IRQ_HANDLED;
> +#endif
>   }
>
> -static const struct file_operations bcm63xx_wdt_fops = {
> -	.owner		= THIS_MODULE,
> -	.llseek		= no_llseek,
> -	.write		= bcm63xx_wdt_write,
> -	.unlocked_ioctl	= bcm63xx_wdt_ioctl,
> -	.open		= bcm63xx_wdt_open,
> -	.release	= bcm63xx_wdt_release,
> +static struct watchdog_ops bcm63xx_wdt_ops = {
> +	.owner = THIS_MODULE,
> +	.start = bcm63xx_wdt_start,
> +	.stop = bcm63xx_wdt_stop,
> +	.get_timeleft = bcm63xx_wdt_get_timeleft,
> +	.set_timeout = bcm63xx_wdt_set_timeout,
>   };
>
> -static struct miscdevice bcm63xx_wdt_miscdev = {
> -	.minor	= WATCHDOG_MINOR,
> -	.name	= "watchdog",
> -	.fops	= &bcm63xx_wdt_fops,
> +static const struct watchdog_info bcm63xx_wdt_info = {
> +	.options = WDIOC_GETTIMELEFT | WDIOF_SETTIMEOUT |
> +			WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
> +	.identity = "BCM63xx Watchdog",
>   };
>
> -
>   static int bcm63xx_wdt_probe(struct platform_device *pdev)
>   {
> -	int ret;
> +	struct bcm63xx_wdt_hw *hw;
> +	struct watchdog_device *wdd;
>   	struct resource *r;
> +	unsigned int timeleft;
> +	int ret;
>
> -	setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
> +	hw = devm_kzalloc(&pdev->dev, sizeof(*hw), GFP_KERNEL);
> +	wdd = devm_kzalloc(&pdev->dev, sizeof(*wdd), GFP_KERNEL);
> +	if (!hw || !wdd)
> +		return -ENOMEM;
>
>   	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>   	if (!r) {
> @@ -248,63 +179,145 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
>   		return -ENODEV;
>   	}
>
> -	bcm63xx_wdt_device.regs = devm_ioremap_nocache(&pdev->dev, r->start,
> -							resource_size(r));
> -	if (!bcm63xx_wdt_device.regs) {
> +	hw->base = devm_ioremap_nocache(&pdev->dev, r->start, resource_size(r));
> +	if (!hw->base) {
>   		dev_err(&pdev->dev, "failed to remap I/O resources\n");
>   		return -ENXIO;
>   	}
>
> -	ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
> -	if (ret < 0) {
> -		dev_err(&pdev->dev, "failed to register wdt timer isr\n");
> +#ifdef CONFIG_BCM63XX
> +	hw->clk = devm_clk_get(&pdev->dev, "periph");
> +#else
> +	hw->clk = devm_clk_get(&pdev->dev, NULL);
> +#endif
> +	if (IS_ERR(hw->clk)) {
> +		dev_err(&pdev->dev, "unable to request clock\n");
> +		return PTR_ERR(hw->clk);
> +	}
> +
> +	hw->clock_hz = clk_get_rate(hw->clk);
> +	if (!hw->clock_hz) {
> +		dev_err(&pdev->dev, "unable to fetch clock rate\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = clk_prepare_enable(hw->clk);
> +	if (ret) {
> +		dev_err(&pdev->dev, "unable to enable clock\n");
>   		return ret;
>   	}
>
> -	if (bcm63xx_wdt_settimeout(wdt_time)) {
> -		bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
> -		dev_info(&pdev->dev,
> -			": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
> -			wdt_time);
> +	raw_spin_lock_init(&hw->lock);
> +	hw->running = false;
> +
> +	wdd->parent = &pdev->dev;
> +	wdd->ops = &bcm63xx_wdt_ops;
> +	wdd->info = &bcm63xx_wdt_info;
> +	wdd->min_timeout = 1;
> +	wdd->max_timeout = 0xffffffff / hw->clock_hz;
> +	wdd->timeout = min(30U, wdd->max_timeout);
> +
> +	watchdog_set_drvdata(wdd, hw);
> +	platform_set_drvdata(pdev, wdd);
> +
> +	watchdog_init_timeout(wdd, 0, &pdev->dev);
> +	watchdog_set_nowayout(wdd, nowayout);
> +
> +	timeleft = bcm63xx_wdt_get_timeleft(wdd);
> +	if (timeleft > 0)
> +		hw->running = true;
> +
> +#ifdef CONFIG_BCM63XX
> +	ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_interrupt, wdd);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to register with bcm63xx_timer\n");
> +		goto disable_clk;
>   	}
> +	hw->irq = 0;
> +#endif
>
> -	ret = misc_register(&bcm63xx_wdt_miscdev);
> +	ret = watchdog_register_device(wdd);
>   	if (ret < 0) {
>   		dev_err(&pdev->dev, "failed to register watchdog device\n");
> +#ifdef CONFIG_BCM63XX
>   		goto unregister_timer;
> +#else
> +		goto disable_clk;
> +#endif
>   	}
>
> -	dev_info(&pdev->dev, " started, timer margin: %d sec\n",
> -						WDT_DEFAULT_TIME);
> +#ifndef CONFIG_BCM63XX
> +	hw->irq = platform_get_irq(pdev, 0);
> +	if (hw->irq) {
> +		ret = devm_request_irq(&pdev->dev, hw->irq,
> +			bcm63xx_wdt_interrupt, IRQF_TIMER,
> +			dev_name(&pdev->dev), wdd);
> +		if (ret)
> +			hw->irq = 0;
> +	}
> +#endif
> +
> +	if (hw->irq) {
> +		dev_info(&pdev->dev,
> +			"%s at MMIO 0x%p (irq = %d, timeout = %us, max_timeout = %us)",
> +			dev_name(wdd->dev), hw->base, hw->irq,
> +			wdd->timeout, wdd->max_timeout);
> +	} else {
> +		dev_info(&pdev->dev,
> +			"%s at MMIO 0x%p (timeout = %us, max_timeout = %us)",
> +			dev_name(wdd->dev), hw->base,
> +			wdd->timeout, wdd->max_timeout);
> +	}
>
> +	if (timeleft > 0)
> +		dev_alert(wdd->dev, "running, reboot in %us\n", timeleft);
>   	return 0;
>
> +#ifdef CONFIG_BCM63XX
>   unregister_timer:
>   	bcm63xx_timer_unregister(TIMER_WDT_ID);
> +#endif
> +disable_clk:
> +	clk_disable(hw->clk);
>   	return ret;
>   }
>
>   static int bcm63xx_wdt_remove(struct platform_device *pdev)
>   {
> -	if (!nowayout)
> -		bcm63xx_wdt_pause();
> +	struct watchdog_device *wdd = platform_get_drvdata(pdev);
> +	struct bcm63xx_wdt_hw *hw = watchdog_get_drvdata(wdd);
>
> -	misc_deregister(&bcm63xx_wdt_miscdev);
> +	if (hw->irq)
> +		devm_free_irq(&pdev->dev, hw->irq, wdd);
> +
> +#ifdef CONFIG_BCM63XX
>   	bcm63xx_timer_unregister(TIMER_WDT_ID);
> +#endif
> +	watchdog_unregister_device(wdd);
> +	clk_disable(hw->clk);
>   	return 0;
>   }
>
>   static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
>   {
> -	bcm63xx_wdt_pause();
> +	struct watchdog_device *wdd = platform_get_drvdata(pdev);
> +
> +	bcm63xx_wdt_stop(wdd);
>   }
>
> +static const struct of_device_id bcm63xx_wdt_dt_ids[] = {
> +	{ .compatible = "brcm,bcm6345-wdt" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, bcm63xx_wdt_dt_ids);
> +
>   static struct platform_driver bcm63xx_wdt_driver = {
>   	.probe	= bcm63xx_wdt_probe,
>   	.remove = bcm63xx_wdt_remove,
>   	.shutdown = bcm63xx_wdt_shutdown,
>   	.driver = {
>   		.name = "bcm63xx-wdt",
> +		.of_match_table = bcm63xx_wdt_dt_ids,
>   	}
>   };
>
> @@ -312,6 +325,7 @@ module_platform_driver(bcm63xx_wdt_driver);
>
>   MODULE_AUTHOR("Miguel Gaio <miguel.gaio@xxxxxxxxx>");
>   MODULE_AUTHOR("Florian Fainelli <florian@xxxxxxxxxxx>");
> +MODULE_AUTHOR("Simon Arlott");
>   MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
>   MODULE_LICENSE("GPL");
>   MODULE_ALIAS("platform:bcm63xx-wdt");
> diff --git a/include/linux/bcm63xx_wdt.h b/include/linux/bcm63xx_wdt.h
> new file mode 100644
> index 0000000..ef4792e
> --- /dev/null
> +++ b/include/linux/bcm63xx_wdt.h
> @@ -0,0 +1,22 @@
> +#ifndef LINUX_BCM63XX_WDT_H_
> +#define LINUX_BCM63XX_WDT_H_
> +
> +/* Watchdog default count register */
> +#define WDT_DEFVAL_REG			0x0
> +
> +/* Watchdog control register */
> +#define WDT_CTL_REG			0x4
> +
> +/* Watchdog control register constants */
> +#define WDT_START_1			(0xff00)
> +#define WDT_START_2			(0x00ff)
> +#define WDT_STOP_1			(0xee00)
> +#define WDT_STOP_2			(0x00ee)
> +
> +/* Watchdog reset length register (in clock ticks) */
> +#define WDT_RSTLEN_REG			0x8
> +
> +/* Watchdog soft reset register (BCM6328 only) */
> +#define WDT_SOFTRESET_REG		0xc
> +
> +#endif

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