[deliverable/linux.git] / drivers / watchdog / at32ap700x_wdt.c

/*
 * Watchdog driver for Atmel AT32AP700X devices
 *
 * Copyright (C) 2005-2006 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *
 * Errata: WDT Clear is blocked after WDT Reset
 *
 * A watchdog timer event will, after reset, block writes to the WDT_CLEAR
 * register, preventing the program to clear the next Watchdog Timer Reset.
 *
 * If you still want to use the WDT after a WDT reset a small code can be
 * insterted at the startup checking the AVR32_PM.rcause register for WDT reset
 * and use a GPIO pin to reset the system. This method requires that one of the
 * GPIO pins are available and connected externally to the RESET_N pin. After
 * the GPIO pin has pulled down the reset line the GPIO will be reset and leave
 * the pin tristated with pullup.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/spinlock.h>

#define TIMEOUT_MIN		1
#define TIMEOUT_MAX		2
#define TIMEOUT_DEFAULT		TIMEOUT_MAX

/* module parameters */
static int timeout =  TIMEOUT_DEFAULT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
		"Timeout value. Limited to be 1 or 2 seconds. (default="
		__MODULE_STRING(TIMEOUT_DEFAULT) ")");

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

/* Watchdog registers and write/read macro */
#define WDT_CTRL		0x00
#define WDT_CTRL_EN		   0
#define WDT_CTRL_PSEL		   8
#define WDT_CTRL_KEY		  24

#define WDT_CLR			0x04

#define WDT_RCAUSE		0x10
#define WDT_RCAUSE_POR		   0
#define WDT_RCAUSE_EXT		   2
#define WDT_RCAUSE_WDT		   3
#define WDT_RCAUSE_JTAG		   4
#define WDT_RCAUSE_SERP		   5

#define WDT_BIT(name)		(1 << WDT_##name)
#define WDT_BF(name, value)	((value) << WDT_##name)

#define wdt_readl(dev, reg)				\
	__raw_readl((dev)->regs + WDT_##reg)
#define wdt_writel(dev, reg, value)			\
	__raw_writel((value), (dev)->regs + WDT_##reg)

struct wdt_at32ap700x {
	void __iomem		*regs;
	spinlock_t		io_lock;
	int			timeout;
	int			boot_status;
	unsigned long		users;
	struct miscdevice	miscdev;
};

static struct wdt_at32ap700x *wdt;
static char expect_release;

/*
 * Disable the watchdog.
 */
static inline void at32_wdt_stop(void)
{
	unsigned long psel;

	spin_lock(&wdt->io_lock);
	psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
	wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55));
	wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa));
	spin_unlock(&wdt->io_lock);
}

/*
 * Enable and reset the watchdog.
 */
static inline void at32_wdt_start(void)
{
	/* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
	unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;

	spin_lock(&wdt->io_lock);
	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
			| WDT_BF(CTRL_PSEL, psel)
			| WDT_BF(CTRL_KEY, 0x55));
	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
			| WDT_BF(CTRL_PSEL, psel)
			| WDT_BF(CTRL_KEY, 0xaa));
	spin_unlock(&wdt->io_lock);
}

/*
 * Pat the watchdog timer.
 */
static inline void at32_wdt_pat(void)
{
	spin_lock(&wdt->io_lock);
	wdt_writel(wdt, CLR, 0x42);
	spin_unlock(&wdt->io_lock);
}

/*
 * Watchdog device is opened, and watchdog starts running.
 */
static int at32_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(1, &wdt->users))
		return -EBUSY;

	at32_wdt_start();
	return nonseekable_open(inode, file);
}

/*
 * Close the watchdog device.
 */
static int at32_wdt_close(struct inode *inode, struct file *file)
{
	if (expect_release == 42) {
		at32_wdt_stop();
	} else {
		dev_dbg(wdt->miscdev.parent,
			"unexpected close, not stopping watchdog!\n");
		at32_wdt_pat();
	}
	clear_bit(1, &wdt->users);
	expect_release = 0;
	return 0;
}

/*
 * Change the watchdog time interval.
 */
static int at32_wdt_settimeout(int time)
{
	/*
	 * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
	 * 2 ^ 16 allowing up to 2 seconds timeout.
	 */
	if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX))
		return -EINVAL;

	/*
	 * Set new watchdog time. It will be used when at32_wdt_start() is
	 * called.
	 */
	wdt->timeout = time;
	return 0;
}

/*
 * Get the watchdog status.
 */
static int at32_wdt_get_status(void)
{
	int rcause;
	int status = 0;

	rcause = wdt_readl(wdt, RCAUSE);

	switch (rcause) {
	case WDT_BIT(RCAUSE_EXT):
		status = WDIOF_EXTERN1;
		break;
	case WDT_BIT(RCAUSE_WDT):
		status = WDIOF_CARDRESET;
		break;
	case WDT_BIT(RCAUSE_POR):  /* fall through */
	case WDT_BIT(RCAUSE_JTAG): /* fall through */
	case WDT_BIT(RCAUSE_SERP): /* fall through */
	default:
		break;
	}

	return status;
}

static struct watchdog_info at32_wdt_info = {
	.identity	= "at32ap700x watchdog",
	.options	= WDIOF_SETTIMEOUT |
			  WDIOF_KEEPALIVEPING |
			  WDIOF_MAGICCLOSE,
};

/*
 * Handle commands from user-space.
 */
static int at32_wdt_ioctl(struct inode *inode, struct file *file,
		unsigned int cmd, unsigned long arg)
{
	int ret = -ENOTTY;
	int time;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;

	switch (cmd) {
	case WDIOC_KEEPALIVE:
		at32_wdt_pat();
		ret = 0;
		break;
	case WDIOC_GETSUPPORT:
		ret = copy_to_user(argp, &at32_wdt_info,
				sizeof(at32_wdt_info)) ? -EFAULT : 0;
		break;
	case WDIOC_SETTIMEOUT:
		ret = get_user(time, p);
		if (ret)
			break;
		ret = at32_wdt_settimeout(time);
		if (ret)
			break;
		/* Enable new time value */
		at32_wdt_start();
		/* fall through */
	case WDIOC_GETTIMEOUT:
		ret = put_user(wdt->timeout, p);
		break;
	case WDIOC_GETSTATUS:
		ret = put_user(0, p);
		break;
	case WDIOC_GETBOOTSTATUS:
		ret = put_user(wdt->boot_status, p);
		break;
	case WDIOC_SETOPTIONS:
		ret = get_user(time, p);
		if (ret)
			break;
		if (time & WDIOS_DISABLECARD)
			at32_wdt_stop();
		if (time & WDIOS_ENABLECARD)
			at32_wdt_start();
		ret = 0;
		break;
	}

	return ret;
}

static ssize_t at32_wdt_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;

			/*
			 * note: just in case someone wrote the magic
			 * character five months ago...
			 */
			expect_release = 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_release = 42;
			}
		}
		/* someone wrote to us, we should pat the watchdog */
		at32_wdt_pat();
	}
	return len;
}

static const struct file_operations at32_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.ioctl		= at32_wdt_ioctl,
	.open		= at32_wdt_open,
	.release	= at32_wdt_close,
	.write		= at32_wdt_write,
};

static int __init at32_wdt_probe(struct platform_device *pdev)
{
	struct resource	*regs;
	int ret;

	if (wdt) {
		dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
		return -EBUSY;
	}

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!regs) {
		dev_dbg(&pdev->dev, "missing mmio resource\n");
		return -ENXIO;
	}

	wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL);
	if (!wdt) {
		dev_dbg(&pdev->dev, "no memory for wdt structure\n");
		return -ENOMEM;
	}

	wdt->regs = ioremap(regs->start, regs->end - regs->start + 1);
	if (!wdt->regs) {
		ret = -ENOMEM;
		dev_dbg(&pdev->dev, "could not map I/O memory\n");
		goto err_free;
	}

	spin_lock_init(&wdt->io_lock);
	wdt->boot_status = at32_wdt_get_status();

	/* Work-around for watchdog silicon errata. */
	if (wdt->boot_status & WDIOF_CARDRESET) {
		dev_info(&pdev->dev, "CPU must be reset with external "
				"reset or POR due to silicon errata.\n");
		ret = -EIO;
		goto err_iounmap;
	} else {
		wdt->users = 0;
	}
	wdt->miscdev.minor = WATCHDOG_MINOR;
	wdt->miscdev.name = "watchdog";
	wdt->miscdev.fops = &at32_wdt_fops;

	if (at32_wdt_settimeout(timeout)) {
		at32_wdt_settimeout(TIMEOUT_DEFAULT);
		dev_dbg(&pdev->dev,
			"default timeout invalid, set to %d sec.\n",
			TIMEOUT_DEFAULT);
	}

	ret = misc_register(&wdt->miscdev);
	if (ret) {
		dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
		goto err_iounmap;
	}

	platform_set_drvdata(pdev, wdt);
	wdt->miscdev.parent = &pdev->dev;
	dev_info(&pdev->dev,
		"AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n",
		wdt->regs, wdt->timeout, nowayout);

	return 0;

err_iounmap:
	iounmap(wdt->regs);
err_free:
	kfree(wdt);
	wdt = NULL;
	return ret;
}

static int __exit at32_wdt_remove(struct platform_device *pdev)
{
	if (wdt && platform_get_drvdata(pdev) == wdt) {
		/* Stop the timer before we leave */
		if (!nowayout)
			at32_wdt_stop();

		misc_deregister(&wdt->miscdev);
		iounmap(wdt->regs);
		kfree(wdt);
		wdt = NULL;
		platform_set_drvdata(pdev, NULL);
	}

	return 0;
}

static void at32_wdt_shutdown(struct platform_device *pdev)
{
	at32_wdt_stop();
}

#ifdef CONFIG_PM
static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
{
	at32_wdt_stop();
	return 0;
}

static int at32_wdt_resume(struct platform_device *pdev)
{
	if (wdt->users)
		at32_wdt_start();
	return 0;
}
#else
#define at32_wdt_suspend NULL
#define at32_wdt_resume NULL
#endif

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:at32_wdt");

static struct platform_driver at32_wdt_driver = {
	.remove		= __exit_p(at32_wdt_remove),
	.suspend	= at32_wdt_suspend,
	.resume		= at32_wdt_resume,
	.driver		= {
		.name	= "at32_wdt",
		.owner	= THIS_MODULE,
	},
	.shutdown	= at32_wdt_shutdown,
};

static int __init at32_wdt_init(void)
{
	return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe);
}
module_init(at32_wdt_init);

static void __exit at32_wdt_exit(void)
{
	platform_driver_unregister(&at32_wdt_driver);
}
module_exit(at32_wdt_exit);

MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
a9cb3959 HCE	1	/*
	2	* Watchdog driver for Atmel AT32AP700X devices
	3	*
	4	* Copyright (C) 2005-2006 Atmel Corporation
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
bb133450 HCE	9	*
	10	*
	11	* Errata: WDT Clear is blocked after WDT Reset
	12	*
	13	* A watchdog timer event will, after reset, block writes to the WDT_CLEAR
	14	* register, preventing the program to clear the next Watchdog Timer Reset.
	15	*
	16	* If you still want to use the WDT after a WDT reset a small code can be
	17	* insterted at the startup checking the AVR32_PM.rcause register for WDT reset
	18	* and use a GPIO pin to reset the system. This method requires that one of the
	19	* GPIO pins are available and connected externally to the RESET_N pin. After
	20	* the GPIO pin has pulled down the reset line the GPIO will be reset and leave
	21	* the pin tristated with pullup.
a9cb3959 HCE	22	*/
	23
	24	#include <linux/init.h>
	25	#include <linux/kernel.h>
	26	#include <linux/module.h>
	27	#include <linux/moduleparam.h>
	28	#include <linux/miscdevice.h>
	29	#include <linux/fs.h>
	30	#include <linux/platform_device.h>
	31	#include <linux/watchdog.h>
c37f2713 AM	32	#include <linux/uaccess.h>
c37f2713 AM	33	#include <linux/io.h>
e75e6577	34	#include <linux/spinlock.h>
a9cb3959 HCE	35
a9cb3959 HCE	36	#define TIMEOUT_MIN 1
a9cb3959	37	#define TIMEOUT_MAX 2
726c9f61 WVS	38	#define TIMEOUT_DEFAULT TIMEOUT_MAX
	39
	40	/* module parameters */
	41	static int timeout = TIMEOUT_DEFAULT;
	42	module_param(timeout, int, 0);
	43	MODULE_PARM_DESC(timeout,
	44	"Timeout value. Limited to be 1 or 2 seconds. (default="
	45	__MODULE_STRING(TIMEOUT_DEFAULT) ")");
a9cb3959	46
28401140 WVS	47	static int nowayout = WATCHDOG_NOWAYOUT;
	48	module_param(nowayout, int, 0);
	49	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	50	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	51
a9cb3959 HCE	52	/* Watchdog registers and write/read macro */
	53	#define WDT_CTRL 0x00
	54	#define WDT_CTRL_EN 0
	55	#define WDT_CTRL_PSEL 8
	56	#define WDT_CTRL_KEY 24
	57
	58	#define WDT_CLR 0x04
	59
bb133450 HCE	60	#define WDT_RCAUSE 0x10
	61	#define WDT_RCAUSE_POR 0
	62	#define WDT_RCAUSE_EXT 2
	63	#define WDT_RCAUSE_WDT 3
	64	#define WDT_RCAUSE_JTAG 4
	65	#define WDT_RCAUSE_SERP 5
	66
a9cb3959	67	#define WDT_BIT(name) (1 << WDT_##name)
c0ead7e0	68	#define WDT_BF(name, value) ((value) << WDT_##name)
a9cb3959	69
c0ead7e0	70	#define wdt_readl(dev, reg) \
a9cb3959	71	__raw_readl((dev)->regs + WDT_##reg)
c0ead7e0	72	#define wdt_writel(dev, reg, value) \
a9cb3959 HCE	73	__raw_writel((value), (dev)->regs + WDT_##reg)
	74
	75	struct wdt_at32ap700x {
	76	void __iomem *regs;
e75e6577	77	spinlock_t io_lock;
a9cb3959	78	int timeout;
bb133450	79	int boot_status;
7e2a1498	80	unsigned long users;
a9cb3959 HCE	81	struct miscdevice miscdev;
	82	};
	83
	84	static struct wdt_at32ap700x *wdt;
28401140	85	static char expect_release;
a9cb3959 HCE	86
	87	/*
	88	* Disable the watchdog.
	89	*/
c0ead7e0	90	static inline void at32_wdt_stop(void)
a9cb3959	91	{
7e2a1498 WVS	92	unsigned long psel;
7e2a1498 WVS	93
e75e6577	94	spin_lock(&wdt->io_lock);
7e2a1498	95	psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
a9cb3959 HCE	96	wdt_writel(wdt, CTRL, psel \| WDT_BF(CTRL_KEY, 0x55));
a9cb3959 HCE	97	wdt_writel(wdt, CTRL, psel \| WDT_BF(CTRL_KEY, 0xaa));
e75e6577	98	spin_unlock(&wdt->io_lock);
a9cb3959 HCE	99	}
	100
	101	/*
	102	* Enable and reset the watchdog.
	103	*/
c0ead7e0	104	static inline void at32_wdt_start(void)
a9cb3959 HCE	105	{
	106	/* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
	107	unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
	108
e75e6577	109	spin_lock(&wdt->io_lock);
a9cb3959 HCE	110	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
	111	\| WDT_BF(CTRL_PSEL, psel)
	112	\| WDT_BF(CTRL_KEY, 0x55));
	113	wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
	114	\| WDT_BF(CTRL_PSEL, psel)
	115	\| WDT_BF(CTRL_KEY, 0xaa));
e75e6577	116	spin_unlock(&wdt->io_lock);
a9cb3959 HCE	117	}
	118
	119	/*
	120	* Pat the watchdog timer.
	121	*/
c0ead7e0	122	static inline void at32_wdt_pat(void)
a9cb3959	123	{
e75e6577	124	spin_lock(&wdt->io_lock);
a9cb3959	125	wdt_writel(wdt, CLR, 0x42);
e75e6577	126	spin_unlock(&wdt->io_lock);
a9cb3959 HCE	127	}
	128
	129	/*
	130	* Watchdog device is opened, and watchdog starts running.
	131	*/
	132	static int at32_wdt_open(struct inode inode, struct file file)
	133	{
	134	if (test_and_set_bit(1, &wdt->users))
	135	return -EBUSY;
	136
	137	at32_wdt_start();
	138	return nonseekable_open(inode, file);
	139	}
	140
	141	/*
28401140	142	* Close the watchdog device.
a9cb3959 HCE	143	*/
	144	static int at32_wdt_close(struct inode inode, struct file file)
	145	{
28401140 WVS	146	if (expect_release == 42) {
	147	at32_wdt_stop();
	148	} else {
	149	dev_dbg(wdt->miscdev.parent,
bb133450	150	"unexpected close, not stopping watchdog!\n");
28401140 WVS	151	at32_wdt_pat();
28401140 WVS	152	}
a9cb3959	153	clear_bit(1, &wdt->users);
28401140	154	expect_release = 0;
a9cb3959 HCE	155	return 0;
	156	}
	157
	158	/*
	159	* Change the watchdog time interval.
	160	*/
	161	static int at32_wdt_settimeout(int time)
	162	{
	163	/*
	164	* All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
	165	* 2 ^ 16 allowing up to 2 seconds timeout.
	166	*/
	167	if ((time < TIMEOUT_MIN) \|\| (time > TIMEOUT_MAX))
	168	return -EINVAL;
	169
c37f2713 AM	170	/*
	171	* Set new watchdog time. It will be used when at32_wdt_start() is
	172	* called.
	173	*/
a9cb3959 HCE	174	wdt->timeout = time;
	175	return 0;
	176	}
	177
bb133450 HCE	178	/*
	179	* Get the watchdog status.
	180	*/
	181	static int at32_wdt_get_status(void)
	182	{
	183	int rcause;
	184	int status = 0;
	185
	186	rcause = wdt_readl(wdt, RCAUSE);
	187
	188	switch (rcause) {
	189	case WDT_BIT(RCAUSE_EXT):
	190	status = WDIOF_EXTERN1;
	191	break;
	192	case WDT_BIT(RCAUSE_WDT):
	193	status = WDIOF_CARDRESET;
	194	break;
	195	case WDT_BIT(RCAUSE_POR): /* fall through */
	196	case WDT_BIT(RCAUSE_JTAG): /* fall through */
	197	case WDT_BIT(RCAUSE_SERP): /* fall through */
	198	default:
	199	break;
	200	}
	201
	202	return status;
	203	}
	204
a9cb3959 HCE	205	static struct watchdog_info at32_wdt_info = {
a9cb3959 HCE	206	.identity = "at32ap700x watchdog",
28401140 WVS	207	.options = WDIOF_SETTIMEOUT \|
	208	WDIOF_KEEPALIVEPING \|
	209	WDIOF_MAGICCLOSE,
a9cb3959 HCE	210	};
	211
	212	/*
	213	* Handle commands from user-space.
	214	*/
	215	static int at32_wdt_ioctl(struct inode inode, struct file file,
	216	unsigned int cmd, unsigned long arg)
	217	{
	218	int ret = -ENOTTY;
	219	int time;
	220	void __user argp = (void __user )arg;
	221	int __user *p = argp;
	222
c37f2713	223	switch (cmd) {
a9cb3959 HCE	224	case WDIOC_KEEPALIVE:
	225	at32_wdt_pat();
	226	ret = 0;
	227	break;
	228	case WDIOC_GETSUPPORT:
	229	ret = copy_to_user(argp, &at32_wdt_info,
	230	sizeof(at32_wdt_info)) ? -EFAULT : 0;
	231	break;
	232	case WDIOC_SETTIMEOUT:
	233	ret = get_user(time, p);
	234	if (ret)
	235	break;
	236	ret = at32_wdt_settimeout(time);
	237	if (ret)
	238	break;
	239	/* Enable new time value */
	240	at32_wdt_start();
	241	/* fall through */
	242	case WDIOC_GETTIMEOUT:
	243	ret = put_user(wdt->timeout, p);
	244	break;
bb133450	245	case WDIOC_GETSTATUS:
a9cb3959 HCE	246	ret = put_user(0, p);
a9cb3959 HCE	247	break;
bb133450 HCE	248	case WDIOC_GETBOOTSTATUS:
	249	ret = put_user(wdt->boot_status, p);
	250	break;
a9cb3959 HCE	251	case WDIOC_SETOPTIONS:
	252	ret = get_user(time, p);
	253	if (ret)
	254	break;
	255	if (time & WDIOS_DISABLECARD)
	256	at32_wdt_stop();
	257	if (time & WDIOS_ENABLECARD)
	258	at32_wdt_start();
	259	ret = 0;
	260	break;
	261	}
	262
	263	return ret;
	264	}
	265
28401140 WVS	266	static ssize_t at32_wdt_write(struct file file, const char __user data,
28401140 WVS	267	size_t len, loff_t *ppos)
a9cb3959	268	{
28401140 WVS	269	/* See if we got the magic character 'V' and reload the timer */
	270	if (len) {
	271	if (!nowayout) {
	272	size_t i;
	273
	274	/*
	275	* note: just in case someone wrote the magic
	276	* character five months ago...
	277	*/
	278	expect_release = 0;
	279
	280	/*
	281	* scan to see whether or not we got the magic
	282	* character
	283	*/
	284	for (i = 0; i != len; i++) {
	285	char c;
	286	if (get_user(c, data+i))
	287	return -EFAULT;
	288	if (c == 'V')
	289	expect_release = 42;
	290	}
	291	}
	292	/* someone wrote to us, we should pat the watchdog */
	293	at32_wdt_pat();
	294	}
a9cb3959 HCE	295	return len;
	296	}
	297
	298	static const struct file_operations at32_wdt_fops = {
	299	.owner = THIS_MODULE,
	300	.llseek = no_llseek,
	301	.ioctl = at32_wdt_ioctl,
	302	.open = at32_wdt_open,
	303	.release = at32_wdt_close,
	304	.write = at32_wdt_write,
	305	};
	306
	307	static int __init at32_wdt_probe(struct platform_device *pdev)
	308	{
	309	struct resource *regs;
	310	int ret;
	311
	312	if (wdt) {
	313	dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
	314	return -EBUSY;
	315	}
	316
	317	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	318	if (!regs) {
	319	dev_dbg(&pdev->dev, "missing mmio resource\n");
	320	return -ENXIO;
	321	}
	322
	323	wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL);
	324	if (!wdt) {
	325	dev_dbg(&pdev->dev, "no memory for wdt structure\n");
	326	return -ENOMEM;
	327	}
	328
	329	wdt->regs = ioremap(regs->start, regs->end - regs->start + 1);
47d17763 HCE	330	if (!wdt->regs) {
	331	ret = -ENOMEM;
	332	dev_dbg(&pdev->dev, "could not map I/O memory\n");
	333	goto err_free;
	334	}
bb133450	335
e75e6577	336	spin_lock_init(&wdt->io_lock);
bb133450 HCE	337	wdt->boot_status = at32_wdt_get_status();
	338
	339	/* Work-around for watchdog silicon errata. */
	340	if (wdt->boot_status & WDIOF_CARDRESET) {
	341	dev_info(&pdev->dev, "CPU must be reset with external "
	342	"reset or POR due to silicon errata.\n");
	343	ret = -EIO;
	344	goto err_iounmap;
	345	} else {
	346	wdt->users = 0;
	347	}
a9cb3959 HCE	348	wdt->miscdev.minor = WATCHDOG_MINOR;
	349	wdt->miscdev.name = "watchdog";
	350	wdt->miscdev.fops = &at32_wdt_fops;
	351
726c9f61 WVS	352	if (at32_wdt_settimeout(timeout)) {
726c9f61 WVS	353	at32_wdt_settimeout(TIMEOUT_DEFAULT);
a9cb3959 HCE	354	dev_dbg(&pdev->dev,
a9cb3959 HCE	355	"default timeout invalid, set to %d sec.\n",
726c9f61	356	TIMEOUT_DEFAULT);
a9cb3959 HCE	357	}
	358
	359	ret = misc_register(&wdt->miscdev);
	360	if (ret) {
	361	dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
47d17763	362	goto err_iounmap;
a9cb3959 HCE	363	}
	364
	365	platform_set_drvdata(pdev, wdt);
	366	wdt->miscdev.parent = &pdev->dev;
28401140 WVS	367	dev_info(&pdev->dev,
	368	"AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n",
	369	wdt->regs, wdt->timeout, nowayout);
a9cb3959 HCE	370
	371	return 0;
	372
47d17763 HCE	373	err_iounmap:
	374	iounmap(wdt->regs);
	375	err_free:
a9cb3959 HCE	376	kfree(wdt);
	377	wdt = NULL;
	378	return ret;
	379	}
	380
	381	static int __exit at32_wdt_remove(struct platform_device *pdev)
	382	{
	383	if (wdt && platform_get_drvdata(pdev) == wdt) {
28401140 WVS	384	/* Stop the timer before we leave */
	385	if (!nowayout)
	386	at32_wdt_stop();
	387
a9cb3959	388	misc_deregister(&wdt->miscdev);
ff732316	389	iounmap(wdt->regs);
a9cb3959 HCE	390	kfree(wdt);
	391	wdt = NULL;
	392	platform_set_drvdata(pdev, NULL);
	393	}
	394
	395	return 0;
	396	}
	397
	398	static void at32_wdt_shutdown(struct platform_device *pdev)
	399	{
	400	at32_wdt_stop();
	401	}
	402
	403	#ifdef CONFIG_PM
	404	static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
	405	{
	406	at32_wdt_stop();
	407	return 0;
	408	}
	409
	410	static int at32_wdt_resume(struct platform_device *pdev)
	411	{
	412	if (wdt->users)
	413	at32_wdt_start();
	414	return 0;
	415	}
97a2a2ea AM	416	#else
	417	#define at32_wdt_suspend NULL
	418	#define at32_wdt_resume NULL
a9cb3959 HCE	419	#endif
a9cb3959 HCE	420
f37d193c KS	421	/* work with hotplug and coldplug */
	422	MODULE_ALIAS("platform:at32_wdt");
	423
a9cb3959 HCE	424	static struct platform_driver at32_wdt_driver = {
a9cb3959 HCE	425	.remove = __exit_p(at32_wdt_remove),
a9cb3959 HCE	426	.suspend = at32_wdt_suspend,
a9cb3959 HCE	427	.resume = at32_wdt_resume,
a9cb3959 HCE	428	.driver = {
	429	.name = "at32_wdt",
	430	.owner = THIS_MODULE,
	431	},
	432	.shutdown = at32_wdt_shutdown,
	433	};
	434
	435	static int __init at32_wdt_init(void)
	436	{
	437	return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe);
	438	}
	439	module_init(at32_wdt_init);
	440
	441	static void __exit at32_wdt_exit(void)
	442	{
	443	platform_driver_unregister(&at32_wdt_driver);
	444	}
	445	module_exit(at32_wdt_exit);
	446
	447	MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
	448	MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
	449	MODULE_LICENSE("GPL");
	450	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);