drivers/watchdog/bcm_kona_wdt.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (C) 2013 Broadcom Corporation
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation version 2.
  *
  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  * kind, whether express or implied; without even the implied warranty
  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>

 #define SECWDOG_CTRL_REG		0x00000000
 #define SECWDOG_COUNT_REG		0x00000004

 #define SECWDOG_RESERVED_MASK		0x1dffffff
 #define SECWDOG_WD_LOAD_FLAG		0x10000000
 #define SECWDOG_EN_MASK			0x08000000
 #define SECWDOG_SRSTEN_MASK		0x04000000
 #define SECWDOG_RES_MASK		0x00f00000
 #define SECWDOG_COUNT_MASK		0x000fffff

 #define SECWDOG_MAX_COUNT		SECWDOG_COUNT_MASK
 #define SECWDOG_CLKS_SHIFT		20
 #define SECWDOG_MAX_RES			15
 #define SECWDOG_DEFAULT_RESOLUTION	4
 #define SECWDOG_MAX_TRY			1000

 #define SECS_TO_TICKS(x, w)		((x) << (w)->resolution)
 #define TICKS_TO_SECS(x, w)		((x) >> (w)->resolution)

 #define BCM_KONA_WDT_NAME		"bcm_kona_wdt"

 struct bcm_kona_wdt {
 	void __iomem *base;
 	/*
 	 * One watchdog tick is 1/(2^resolution) seconds. Resolution can take
 	 * the values 0-15, meaning one tick can be 1s to 30.52us. Our default
 	 * resolution of 4 means one tick is 62.5ms.
 	 *
 	 * The watchdog counter is 20 bits. Depending on resolution, the maximum
 	 * counter value of 0xfffff expires after about 12 days (resolution 0)
 	 * down to only 32s (resolution 15). The default resolution of 4 gives
 	 * us a maximum of about 18 hours and 12 minutes before the watchdog
 	 * times out.
 	 */
 	int resolution;
 	spinlock_t lock;
 #ifdef CONFIG_BCM_KONA_WDT_DEBUG
 	unsigned long busy_count;
 	struct dentry *debugfs;
 #endif
 };

 static int secure_register_read(struct bcm_kona_wdt *wdt, uint32_t offset)
 {
 	uint32_t val;
 	unsigned count = 0;

 	/*
 	 * If the WD_LOAD_FLAG is set, the watchdog counter field is being
 	 * updated in hardware. Once the WD timer is updated in hardware, it
 	 * gets cleared.
 	 */
 	do {
 		if (unlikely(count > 1))
 			udelay(5);
 		val = readl_relaxed(wdt->base + offset);
 		count++;
 	} while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY);

 #ifdef CONFIG_BCM_KONA_WDT_DEBUG
 	/* Remember the maximum number iterations due to WD_LOAD_FLAG */
 	if (count > wdt->busy_count)
 		wdt->busy_count = count;
 #endif

 	/* This is the only place we return a negative value. */
 	if (val & SECWDOG_WD_LOAD_FLAG)
 		return -ETIMEDOUT;

 	/* We always mask out reserved bits. */
 	val &= SECWDOG_RESERVED_MASK;

 	return val;
 }

 #ifdef CONFIG_BCM_KONA_WDT_DEBUG

 static int bcm_kona_wdt_dbg_show(struct seq_file *s, void *data)
 {
 	int ctl_val, cur_val;
 	unsigned long flags;
 	struct bcm_kona_wdt *wdt = s->private;

 	if (!wdt) {
 		seq_puts(s, "No device pointer\n");
 		return 0;
 	}

 	spin_lock_irqsave(&wdt->lock, flags);
 	ctl_val = secure_register_read(wdt, SECWDOG_CTRL_REG);
 	cur_val = secure_register_read(wdt, SECWDOG_COUNT_REG);
 	spin_unlock_irqrestore(&wdt->lock, flags);

 	if (ctl_val < 0 || cur_val < 0) {
 		seq_puts(s, "Error accessing hardware\n");
 	} else {
 		int ctl, cur, ctl_sec, cur_sec, res;

 		ctl = ctl_val & SECWDOG_COUNT_MASK;
 		res = (ctl_val & SECWDOG_RES_MASK) >> SECWDOG_CLKS_SHIFT;
 		cur = cur_val & SECWDOG_COUNT_MASK;
 		ctl_sec = TICKS_TO_SECS(ctl, wdt);
 		cur_sec = TICKS_TO_SECS(cur, wdt);
 		seq_printf(s,
 			   "Resolution: %d / %d\n"
 			   "Control: %d s / %d (%#x) ticks\n"
 			   "Current: %d s / %d (%#x) ticks\n"
 			   "Busy count: %lu\n",
 			   res, wdt->resolution,
 			   ctl_sec, ctl, ctl,
 			   cur_sec, cur, cur,
 			   wdt->busy_count);
 	}

 	return 0;
 }

 static int bcm_kona_dbg_open(struct inode *inode, struct file *file)
 {
 	return single_open(file, bcm_kona_wdt_dbg_show, inode->i_private);
 }

 static const struct file_operations bcm_kona_dbg_operations = {
 	.open		= bcm_kona_dbg_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
 	.release	= single_release,
 };

 static void bcm_kona_wdt_debug_init(struct platform_device *pdev)
 {
 	struct dentry *dir;
 	struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);

 	if (!wdt)
 		return;

 	wdt->debugfs = NULL;

 	dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);
 	if (IS_ERR_OR_NULL(dir))
 		return;

 	if (debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,
 				&bcm_kona_dbg_operations))
 		wdt->debugfs = dir;
 	else
 		debugfs_remove_recursive(dir);
 }

 static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)
 {
 	struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);

 	if (wdt && wdt->debugfs) {
 		debugfs_remove_recursive(wdt->debugfs);
 		wdt->debugfs = NULL;
 	}
 }

 #else

 static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {}
 static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {}

 #endif /* CONFIG_BCM_KONA_WDT_DEBUG */

 static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
 					unsigned mask, unsigned newval)
 {
 	int val;
 	unsigned long flags;
 	int ret = 0;

 	spin_lock_irqsave(&wdt->lock, flags);

 	val = secure_register_read(wdt, SECWDOG_CTRL_REG);
 	if (val < 0) {
 		ret = val;
 	} else {
 		val &= ~mask;
 		val |= newval;
 		writel_relaxed(val, wdt->base + SECWDOG_CTRL_REG);
 	}

 	spin_unlock_irqrestore(&wdt->lock, flags);

 	return ret;
 }

 static int bcm_kona_wdt_set_resolution_reg(struct bcm_kona_wdt *wdt)
 {
 	if (wdt->resolution > SECWDOG_MAX_RES)
 		return -EINVAL;

 	return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_RES_MASK,
 					wdt->resolution << SECWDOG_CLKS_SHIFT);
 }

 static int bcm_kona_wdt_set_timeout_reg(struct watchdog_device *wdog,
 					unsigned watchdog_flags)
 {
 	struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);

 	return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_COUNT_MASK,
 					SECS_TO_TICKS(wdog->timeout, wdt) |
 					watchdog_flags);
 }

 static int bcm_kona_wdt_set_timeout(struct watchdog_device *wdog,
 	unsigned int t)
 {
 	wdog->timeout = t;
 	return 0;
 }

 static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)
 {
 	struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
 	int val;
 	unsigned long flags;

 	spin_lock_irqsave(&wdt->lock, flags);
 	val = secure_register_read(wdt, SECWDOG_COUNT_REG);
 	spin_unlock_irqrestore(&wdt->lock, flags);

 	if (val < 0)
 		return val;

 	return TICKS_TO_SECS(val & SECWDOG_COUNT_MASK, wdt);
 }

 static int bcm_kona_wdt_start(struct watchdog_device *wdog)
 {
 	return bcm_kona_wdt_set_timeout_reg(wdog,
 					SECWDOG_EN_MASK | SECWDOG_SRSTEN_MASK);
 }

 static int bcm_kona_wdt_stop(struct watchdog_device *wdog)
 {
 	struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);

 	return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_EN_MASK |
 					    SECWDOG_SRSTEN_MASK, 0);
 }

 static struct watchdog_ops bcm_kona_wdt_ops = {
 	.owner =	THIS_MODULE,
 	.start =	bcm_kona_wdt_start,
 	.stop =		bcm_kona_wdt_stop,
 	.set_timeout =	bcm_kona_wdt_set_timeout,
 	.get_timeleft =	bcm_kona_wdt_get_timeleft,
 };

 static struct watchdog_info bcm_kona_wdt_info = {
 	.options =	WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
 			WDIOF_KEEPALIVEPING,
 	.identity =	"Broadcom Kona Watchdog Timer",
 };

 static struct watchdog_device bcm_kona_wdt_wdd = {
 	.info =		&bcm_kona_wdt_info,
 	.ops =		&bcm_kona_wdt_ops,
 	.min_timeout =	1,
 	.max_timeout =	SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
 	.timeout =	SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
 };

 static void bcm_kona_wdt_shutdown(struct platform_device *pdev)
 {
 	bcm_kona_wdt_stop(&bcm_kona_wdt_wdd);
 }

 static int bcm_kona_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct bcm_kona_wdt *wdt;
 	struct resource *res;
 	int ret;

 	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 	if (!wdt)
 		return -ENOMEM;

 	spin_lock_init(&wdt->lock);

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	wdt->base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(wdt->base))
 		return -ENODEV;

 	wdt->resolution = SECWDOG_DEFAULT_RESOLUTION;
 	ret = bcm_kona_wdt_set_resolution_reg(wdt);
 	if (ret) {
 		dev_err(dev, "Failed to set resolution (error: %d)", ret);
 		return ret;
 	}

 	platform_set_drvdata(pdev, wdt);
 	watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt);
 	bcm_kona_wdt_wdd.parent = &pdev->dev;

 	ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0);
 	if (ret) {
 		dev_err(dev, "Failed set watchdog timeout");
 		return ret;
 	}

 	ret = watchdog_register_device(&bcm_kona_wdt_wdd);
 	if (ret) {
 		dev_err(dev, "Failed to register watchdog device");
 		return ret;
 	}

 	bcm_kona_wdt_debug_init(pdev);
 	dev_dbg(dev, "Broadcom Kona Watchdog Timer");

 	return 0;
 }

 static int bcm_kona_wdt_remove(struct platform_device *pdev)
 {
 	bcm_kona_wdt_debug_exit(pdev);
 	bcm_kona_wdt_shutdown(pdev);
 	watchdog_unregister_device(&bcm_kona_wdt_wdd);
 	dev_dbg(&pdev->dev, "Watchdog driver disabled");

 	return 0;
 }

 static const struct of_device_id bcm_kona_wdt_of_match[] = {
 	{ .compatible = "brcm,kona-wdt", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match);

 static struct platform_driver bcm_kona_wdt_driver = {
 	.driver = {
 			.name = BCM_KONA_WDT_NAME,
 			.of_match_table = bcm_kona_wdt_of_match,
 		  },
 	.probe = bcm_kona_wdt_probe,
 	.remove = bcm_kona_wdt_remove,
 	.shutdown = bcm_kona_wdt_shutdown,
 };

 module_platform_driver(bcm_kona_wdt_driver);

 MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
 MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
 MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Copyright (C) 2013 Broadcom Corporation
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License as
	* published by the Free Software Foundation version 2.
	*
	* This program is distributed "as is" WITHOUT ANY WARRANTY of any
	* kind, whether express or implied; without even the implied warranty
	* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#include <linux/debugfs.h>
	#include <linux/delay.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/of_address.h>
	#include <linux/platform_device.h>
	#include <linux/watchdog.h>

	#define SECWDOG_CTRL_REG 0x00000000
	#define SECWDOG_COUNT_REG 0x00000004

	#define SECWDOG_RESERVED_MASK 0x1dffffff
	#define SECWDOG_WD_LOAD_FLAG 0x10000000
	#define SECWDOG_EN_MASK 0x08000000
	#define SECWDOG_SRSTEN_MASK 0x04000000
	#define SECWDOG_RES_MASK 0x00f00000
	#define SECWDOG_COUNT_MASK 0x000fffff

	#define SECWDOG_MAX_COUNT SECWDOG_COUNT_MASK
	#define SECWDOG_CLKS_SHIFT 20
	#define SECWDOG_MAX_RES 15
	#define SECWDOG_DEFAULT_RESOLUTION 4
	#define SECWDOG_MAX_TRY 1000

	#define SECS_TO_TICKS(x, w) ((x) << (w)->resolution)
	#define TICKS_TO_SECS(x, w) ((x) >> (w)->resolution)

	#define BCM_KONA_WDT_NAME "bcm_kona_wdt"

	struct bcm_kona_wdt {
	void __iomem *base;
	/*
	* One watchdog tick is 1/(2^resolution) seconds. Resolution can take
	* the values 0-15, meaning one tick can be 1s to 30.52us. Our default
	* resolution of 4 means one tick is 62.5ms.
	*
	* The watchdog counter is 20 bits. Depending on resolution, the maximum
	* counter value of 0xfffff expires after about 12 days (resolution 0)
	* down to only 32s (resolution 15). The default resolution of 4 gives
	* us a maximum of about 18 hours and 12 minutes before the watchdog
	* times out.
	*/
	int resolution;
	spinlock_t lock;
	#ifdef CONFIG_BCM_KONA_WDT_DEBUG
	unsigned long busy_count;
	struct dentry *debugfs;
	#endif
	};

	static int secure_register_read(struct bcm_kona_wdt *wdt, uint32_t offset)
	{
	uint32_t val;
	unsigned count = 0;

	/*
	* If the WD_LOAD_FLAG is set, the watchdog counter field is being
	* updated in hardware. Once the WD timer is updated in hardware, it
	* gets cleared.
	*/
	do {
	if (unlikely(count > 1))
	udelay(5);
	val = readl_relaxed(wdt->base + offset);
	count++;
	} while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY);

	#ifdef CONFIG_BCM_KONA_WDT_DEBUG
	/* Remember the maximum number iterations due to WD_LOAD_FLAG */
	if (count > wdt->busy_count)
	wdt->busy_count = count;
	#endif

	/* This is the only place we return a negative value. */
	if (val & SECWDOG_WD_LOAD_FLAG)
	return -ETIMEDOUT;

	/* We always mask out reserved bits. */
	val &= SECWDOG_RESERVED_MASK;

	return val;
	}

	#ifdef CONFIG_BCM_KONA_WDT_DEBUG

	static int bcm_kona_wdt_dbg_show(struct seq_file s, void data)
	{
	int ctl_val, cur_val;
	unsigned long flags;
	struct bcm_kona_wdt *wdt = s->private;

	if (!wdt) {
	seq_puts(s, "No device pointer\n");
	return 0;
	}

	spin_lock_irqsave(&wdt->lock, flags);
	ctl_val = secure_register_read(wdt, SECWDOG_CTRL_REG);
	cur_val = secure_register_read(wdt, SECWDOG_COUNT_REG);
	spin_unlock_irqrestore(&wdt->lock, flags);

	if (ctl_val < 0 \|\| cur_val < 0) {
	seq_puts(s, "Error accessing hardware\n");
	} else {
	int ctl, cur, ctl_sec, cur_sec, res;

	ctl = ctl_val & SECWDOG_COUNT_MASK;
	res = (ctl_val & SECWDOG_RES_MASK) >> SECWDOG_CLKS_SHIFT;
	cur = cur_val & SECWDOG_COUNT_MASK;
	ctl_sec = TICKS_TO_SECS(ctl, wdt);
	cur_sec = TICKS_TO_SECS(cur, wdt);
	seq_printf(s,
	"Resolution: %d / %d\n"
	"Control: %d s / %d (%#x) ticks\n"
	"Current: %d s / %d (%#x) ticks\n"
	"Busy count: %lu\n",
	res, wdt->resolution,
	ctl_sec, ctl, ctl,
	cur_sec, cur, cur,
	wdt->busy_count);
	}

	return 0;
	}

	static int bcm_kona_dbg_open(struct inode inode, struct file file)
	{
	return single_open(file, bcm_kona_wdt_dbg_show, inode->i_private);
	}

	static const struct file_operations bcm_kona_dbg_operations = {
	.open = bcm_kona_dbg_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
	};

	static void bcm_kona_wdt_debug_init(struct platform_device *pdev)
	{
	struct dentry *dir;
	struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);

	if (!wdt)
	return;

	wdt->debugfs = NULL;

	dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);
	if (IS_ERR_OR_NULL(dir))
	return;

	if (debugfs_create_file("info", S_IFREG \| S_IRUGO, dir, wdt,
	&bcm_kona_dbg_operations))
	wdt->debugfs = dir;
	else
	debugfs_remove_recursive(dir);
	}

	static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)
	{
	struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);

	if (wdt && wdt->debugfs) {
	debugfs_remove_recursive(wdt->debugfs);
	wdt->debugfs = NULL;
	}
	}

	#else

	static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {}
	static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {}

	#endif /* CONFIG_BCM_KONA_WDT_DEBUG */

	static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
	unsigned mask, unsigned newval)
	{
	int val;
	unsigned long flags;
	int ret = 0;

	spin_lock_irqsave(&wdt->lock, flags);

	val = secure_register_read(wdt, SECWDOG_CTRL_REG);
	if (val < 0) {
	ret = val;
	} else {
	val &= ~mask;
	val \|= newval;
	writel_relaxed(val, wdt->base + SECWDOG_CTRL_REG);
	}

	spin_unlock_irqrestore(&wdt->lock, flags);

	return ret;
	}

	static int bcm_kona_wdt_set_resolution_reg(struct bcm_kona_wdt *wdt)
	{
	if (wdt->resolution > SECWDOG_MAX_RES)
	return -EINVAL;

	return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_RES_MASK,
	wdt->resolution << SECWDOG_CLKS_SHIFT);
	}

	static int bcm_kona_wdt_set_timeout_reg(struct watchdog_device *wdog,
	unsigned watchdog_flags)
	{
	struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);

	return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_COUNT_MASK,
	SECS_TO_TICKS(wdog->timeout, wdt) \|
	watchdog_flags);
	}

	static int bcm_kona_wdt_set_timeout(struct watchdog_device *wdog,
	unsigned int t)
	{
	wdog->timeout = t;
	return 0;
	}

	static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)
	{
	struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
	int val;
	unsigned long flags;

	spin_lock_irqsave(&wdt->lock, flags);
	val = secure_register_read(wdt, SECWDOG_COUNT_REG);
	spin_unlock_irqrestore(&wdt->lock, flags);

	if (val < 0)
	return val;

	return TICKS_TO_SECS(val & SECWDOG_COUNT_MASK, wdt);
	}

	static int bcm_kona_wdt_start(struct watchdog_device *wdog)
	{
	return bcm_kona_wdt_set_timeout_reg(wdog,
	SECWDOG_EN_MASK \| SECWDOG_SRSTEN_MASK);
	}

	static int bcm_kona_wdt_stop(struct watchdog_device *wdog)
	{
	struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);

	return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_EN_MASK \|
	SECWDOG_SRSTEN_MASK, 0);
	}

	static struct watchdog_ops bcm_kona_wdt_ops = {
	.owner = THIS_MODULE,
	.start = bcm_kona_wdt_start,
	.stop = bcm_kona_wdt_stop,
	.set_timeout = bcm_kona_wdt_set_timeout,
	.get_timeleft = bcm_kona_wdt_get_timeleft,
	};

	static struct watchdog_info bcm_kona_wdt_info = {
	.options = WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE \|
	WDIOF_KEEPALIVEPING,
	.identity = "Broadcom Kona Watchdog Timer",
	};

	static struct watchdog_device bcm_kona_wdt_wdd = {
	.info = &bcm_kona_wdt_info,
	.ops = &bcm_kona_wdt_ops,
	.min_timeout = 1,
	.max_timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
	.timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
	};

	static void bcm_kona_wdt_shutdown(struct platform_device *pdev)
	{
	bcm_kona_wdt_stop(&bcm_kona_wdt_wdd);
	}

	static int bcm_kona_wdt_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct bcm_kona_wdt *wdt;
	struct resource *res;
	int ret;

	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
	if (!wdt)
	return -ENOMEM;

	spin_lock_init(&wdt->lock);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	wdt->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(wdt->base))
	return -ENODEV;

	wdt->resolution = SECWDOG_DEFAULT_RESOLUTION;
	ret = bcm_kona_wdt_set_resolution_reg(wdt);
	if (ret) {
	dev_err(dev, "Failed to set resolution (error: %d)", ret);
	return ret;
	}

	platform_set_drvdata(pdev, wdt);
	watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt);
	bcm_kona_wdt_wdd.parent = &pdev->dev;

	ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0);
	if (ret) {
	dev_err(dev, "Failed set watchdog timeout");
	return ret;
	}

	ret = watchdog_register_device(&bcm_kona_wdt_wdd);
	if (ret) {
	dev_err(dev, "Failed to register watchdog device");
	return ret;
	}

	bcm_kona_wdt_debug_init(pdev);
	dev_dbg(dev, "Broadcom Kona Watchdog Timer");

	return 0;
	}

	static int bcm_kona_wdt_remove(struct platform_device *pdev)
	{
	bcm_kona_wdt_debug_exit(pdev);
	bcm_kona_wdt_shutdown(pdev);
	watchdog_unregister_device(&bcm_kona_wdt_wdd);
	dev_dbg(&pdev->dev, "Watchdog driver disabled");

	return 0;
	}

	static const struct of_device_id bcm_kona_wdt_of_match[] = {
	{ .compatible = "brcm,kona-wdt", },
	{},
	};
	MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match);

	static struct platform_driver bcm_kona_wdt_driver = {
	.driver = {
	.name = BCM_KONA_WDT_NAME,
	.of_match_table = bcm_kona_wdt_of_match,
	},
	.probe = bcm_kona_wdt_probe,
	.remove = bcm_kona_wdt_remove,
	.shutdown = bcm_kona_wdt_shutdown,
	};

	module_platform_driver(bcm_kona_wdt_driver);

	MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
	MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
	MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
	MODULE_LICENSE("GPL v2");