[mirror_ubuntu-zesty-kernel.git] / drivers / watchdog / stmp3xxx_wdt.c

/*
 * Watchdog driver for Freescale STMP37XX/STMP378X
 *
 * Author: Vitaly Wool <vital@embeddedalley.com>
 *
 * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
 * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/module.h>

#include <mach/platform.h>
#include <mach/regs-rtc.h>

#define DEFAULT_HEARTBEAT	19
#define MAX_HEARTBEAT		(0x10000000 >> 6)

/* missing bitmask in headers */
#define BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER     0x80000000

#define WDT_IN_USE		0
#define WDT_OK_TO_CLOSE		1

#define WDOG_COUNTER_RATE	1000 /* 1 kHz clock */

static DEFINE_SPINLOCK(stmp3xxx_wdt_io_lock);
static unsigned long wdt_status;
static const int nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat = DEFAULT_HEARTBEAT;
static unsigned long boot_status;

static void wdt_enable(u32 value)
{
	spin_lock(&stmp3xxx_wdt_io_lock);
	__raw_writel(value, REGS_RTC_BASE + HW_RTC_WATCHDOG);
	stmp3xxx_setl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
	stmp3xxx_setl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
			REGS_RTC_BASE + HW_RTC_PERSISTENT1);
	spin_unlock(&stmp3xxx_wdt_io_lock);
}

static void wdt_disable(void)
{
	spin_lock(&stmp3xxx_wdt_io_lock);
	stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
			REGS_RTC_BASE + HW_RTC_PERSISTENT1);
	stmp3xxx_clearl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
	spin_unlock(&stmp3xxx_wdt_io_lock);
}

static void wdt_ping(void)
{
	wdt_enable(heartbeat * WDOG_COUNTER_RATE);
}

static int stmp3xxx_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_ping();

	return nonseekable_open(inode, file);
}

static ssize_t stmp3xxx_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);
			}
		}
		wdt_ping();
	}

	return len;
}

static const struct watchdog_info ident = {
	.options	= WDIOF_CARDRESET |
			  WDIOF_MAGICCLOSE |
			  WDIOF_SETTIMEOUT |
			  WDIOF_KEEPALIVEPING,
	.identity	= "STMP3XXX Watchdog",
};

static long stmp3xxx_wdt_ioctl(struct file *file, unsigned int cmd,
	unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_heartbeat, opts;
	int ret = -ENOTTY;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
		ret = put_user(0, p);
		break;

	case WDIOC_GETBOOTSTATUS:
		ret = put_user(boot_status, p);
		break;

	case WDIOC_SETOPTIONS:
		if (get_user(opts, p)) {
			ret = -EFAULT;
			break;
		}
		if (opts & WDIOS_DISABLECARD)
			wdt_disable();
		else if (opts & WDIOS_ENABLECARD)
			wdt_ping();
		else {
			pr_debug("%s: unknown option 0x%x\n", __func__, opts);
			ret = -EINVAL;
			break;
		}
		ret = 0;
		break;

	case WDIOC_KEEPALIVE:
		wdt_ping();
		ret = 0;
		break;

	case WDIOC_SETTIMEOUT:
		if (get_user(new_heartbeat, p)) {
			ret = -EFAULT;
			break;
		}
		if (new_heartbeat <= 0 || new_heartbeat > MAX_HEARTBEAT) {
			ret = -EINVAL;
			break;
		}

		heartbeat = new_heartbeat;
		wdt_ping();
		/* Fall through */

	case WDIOC_GETTIMEOUT:
		ret = put_user(heartbeat, p);
		break;
	}
	return ret;
}

static int stmp3xxx_wdt_release(struct inode *inode, struct file *file)
{
	int ret = 0;

	if (!nowayout) {
		if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
			wdt_ping();
			pr_debug("%s: Device closed unexpectdly\n", __func__);
			ret = -EINVAL;
		} else {
			wdt_disable();
			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
		}
	}
	clear_bit(WDT_IN_USE, &wdt_status);

	return ret;
}

static const struct file_operations stmp3xxx_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = stmp3xxx_wdt_write,
	.unlocked_ioctl = stmp3xxx_wdt_ioctl,
	.open = stmp3xxx_wdt_open,
	.release = stmp3xxx_wdt_release,
};

static struct miscdevice stmp3xxx_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &stmp3xxx_wdt_fops,
};

static int __devinit stmp3xxx_wdt_probe(struct platform_device *pdev)
{
	int ret = 0;

	if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
		heartbeat = DEFAULT_HEARTBEAT;

	boot_status = __raw_readl(REGS_RTC_BASE + HW_RTC_PERSISTENT1) &
			BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER;
	boot_status = !!boot_status;
	stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
			REGS_RTC_BASE + HW_RTC_PERSISTENT1);
	wdt_disable();		/* disable for now */

	ret = misc_register(&stmp3xxx_wdt_miscdev);
	if (ret < 0) {
		dev_err(&pdev->dev, "cannot register misc device\n");
		return ret;
	}

	printk(KERN_INFO "stmp3xxx watchdog: initialized, heartbeat %d sec\n",
		heartbeat);

	return ret;
}

static int __devexit stmp3xxx_wdt_remove(struct platform_device *pdev)
{
	misc_deregister(&stmp3xxx_wdt_miscdev);
	return 0;
}

#ifdef CONFIG_PM
static int wdt_suspended;
static u32 wdt_saved_time;

static int stmp3xxx_wdt_suspend(struct platform_device *pdev,
				pm_message_t state)
{
	if (__raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) &
		BM_RTC_CTRL_WATCHDOGEN) {
		wdt_suspended = 1;
		wdt_saved_time = __raw_readl(REGS_RTC_BASE + HW_RTC_WATCHDOG);
		wdt_disable();
	}
	return 0;
}

static int stmp3xxx_wdt_resume(struct platform_device *pdev)
{
	if (wdt_suspended) {
		wdt_enable(wdt_saved_time);
		wdt_suspended = 0;
	}
	return 0;
}
#else
#define stmp3xxx_wdt_suspend	NULL
#define stmp3xxx_wdt_resume	NULL
#endif

static struct platform_driver platform_wdt_driver = {
	.driver = {
		.name = "stmp3xxx_wdt",
	},
	.probe = stmp3xxx_wdt_probe,
	.remove = __devexit_p(stmp3xxx_wdt_remove),
	.suspend = stmp3xxx_wdt_suspend,
	.resume = stmp3xxx_wdt_resume,
};

static int __init stmp3xxx_wdt_init(void)
{
	return platform_driver_register(&platform_wdt_driver);
}

static void __exit stmp3xxx_wdt_exit(void)
{
	return platform_driver_unregister(&platform_wdt_driver);
}

module_init(stmp3xxx_wdt_init);
module_exit(stmp3xxx_wdt_exit);

MODULE_DESCRIPTION("STMP3XXX Watchdog Driver");
MODULE_LICENSE("GPL");

module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
		 "Watchdog heartbeat period in seconds from 1 to "
		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
		 __MODULE_STRING(DEFAULT_HEARTBEAT));

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
accde168	1	/*
	2	* Watchdog driver for Freescale STMP37XX/STMP378X
	3	*
	4	* Author: Vitaly Wool <vital@embeddedalley.com>
	5	*
	6	* Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
	7	* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
	8	*/
	9	#include <linux/init.h>
	10	#include <linux/kernel.h>
	11	#include <linux/fs.h>
	12	#include <linux/miscdevice.h>
	13	#include <linux/watchdog.h>
	14	#include <linux/platform_device.h>
	15	#include <linux/spinlock.h>
	16	#include <linux/uaccess.h>
e7455b7a	17	#include <linux/module.h>
accde168	18
	19	#include <mach/platform.h>
	20	#include <mach/regs-rtc.h>
	21
	22	#define DEFAULT_HEARTBEAT 19
	23	#define MAX_HEARTBEAT (0x10000000 >> 6)
	24
	25	/* missing bitmask in headers */
	26	#define BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER 0x80000000
	27
	28	#define WDT_IN_USE 0
	29	#define WDT_OK_TO_CLOSE 1
	30
	31	#define WDOG_COUNTER_RATE 1000 /* 1 kHz clock */
	32
	33	static DEFINE_SPINLOCK(stmp3xxx_wdt_io_lock);
	34	static unsigned long wdt_status;
	35	static const int nowayout = WATCHDOG_NOWAYOUT;
	36	static int heartbeat = DEFAULT_HEARTBEAT;
	37	static unsigned long boot_status;
	38
	39	static void wdt_enable(u32 value)
	40	{
	41	spin_lock(&stmp3xxx_wdt_io_lock);
	42	__raw_writel(value, REGS_RTC_BASE + HW_RTC_WATCHDOG);
	43	stmp3xxx_setl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
	44	stmp3xxx_setl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
	45	REGS_RTC_BASE + HW_RTC_PERSISTENT1);
	46	spin_unlock(&stmp3xxx_wdt_io_lock);
	47	}
	48
	49	static void wdt_disable(void)
	50	{
	51	spin_lock(&stmp3xxx_wdt_io_lock);
	52	stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
	53	REGS_RTC_BASE + HW_RTC_PERSISTENT1);
	54	stmp3xxx_clearl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
	55	spin_unlock(&stmp3xxx_wdt_io_lock);
	56	}
	57
	58	static void wdt_ping(void)
	59	{
	60	wdt_enable(heartbeat * WDOG_COUNTER_RATE);
	61	}
	62
	63	static int stmp3xxx_wdt_open(struct inode inode, struct file file)
	64	{
	65	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	66	return -EBUSY;
	67
	68	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	69	wdt_ping();
	70
	71	return nonseekable_open(inode, file);
	72	}
	73
	74	static ssize_t stmp3xxx_wdt_write(struct file file, const char __user data,
	75	size_t len, loff_t *ppos)
	76	{
	77	if (len) {
	78	if (!nowayout) {
	79	size_t i;
	80
	81	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
82
83	for (i = 0; i != len; i++) {
84	char c;
85
86	if (get_user(c, data + i))
87	return -EFAULT;
88	if (c == 'V')
89	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
90	}
91	}
92	wdt_ping();
93	}
94
95	return len;
96	}
97
42747d71	98	static const struct watchdog_info ident = {
accde168	99	.options = WDIOF_CARDRESET \|
	100	WDIOF_MAGICCLOSE \|
	101	WDIOF_SETTIMEOUT \|
	102	WDIOF_KEEPALIVEPING,
	103	.identity = "STMP3XXX Watchdog",
	104	};
	105
	106	static long stmp3xxx_wdt_ioctl(struct file *file, unsigned int cmd,
	107	unsigned long arg)
	108	{
	109	void __user argp = (void __user )arg;
	110	int __user *p = argp;
	111	int new_heartbeat, opts;
	112	int ret = -ENOTTY;
	113
	114	switch (cmd) {
	115	case WDIOC_GETSUPPORT:
	116	ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	117	break;
	118
	119	case WDIOC_GETSTATUS:
	120	ret = put_user(0, p);
	121	break;
	122
	123	case WDIOC_GETBOOTSTATUS:
	124	ret = put_user(boot_status, p);
	125	break;
	126
	127	case WDIOC_SETOPTIONS:
	128	if (get_user(opts, p)) {
	129	ret = -EFAULT;
	130	break;
	131	}
	132	if (opts & WDIOS_DISABLECARD)
	133	wdt_disable();
	134	else if (opts & WDIOS_ENABLECARD)
	135	wdt_ping();
	136	else {
	137	pr_debug("%s: unknown option 0x%x\n", __func__, opts);
	138	ret = -EINVAL;
	139	break;
	140	}
	141	ret = 0;
	142	break;
	143
	144	case WDIOC_KEEPALIVE:
	145	wdt_ping();
	146	ret = 0;
	147	break;
	148
	149	case WDIOC_SETTIMEOUT:
	150	if (get_user(new_heartbeat, p)) {
	151	ret = -EFAULT;
	152	break;
	153	}
	154	if (new_heartbeat <= 0 \|\| new_heartbeat > MAX_HEARTBEAT) {
	155	ret = -EINVAL;
	156	break;
	157	}
	158
	159	heartbeat = new_heartbeat;
	160	wdt_ping();
	161	/* Fall through */
	162
163	case WDIOC_GETTIMEOUT:
164	ret = put_user(heartbeat, p);
165	break;
166	}
167	return ret;
168	}
169
170	static int stmp3xxx_wdt_release(struct inode inode, struct file file)
171	{
172	int ret = 0;
173
174	if (!nowayout) {
175	if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
176	wdt_ping();
177	pr_debug("%s: Device closed unexpectdly\n", __func__);
178	ret = -EINVAL;
179	} else {
180	wdt_disable();
181	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
182	}
183	}
184	clear_bit(WDT_IN_USE, &wdt_status);
185
186	return ret;
187	}
188
189	static const struct file_operations stmp3xxx_wdt_fops = {
190	.owner = THIS_MODULE,
191	.llseek = no_llseek,
192	.write = stmp3xxx_wdt_write,
193	.unlocked_ioctl = stmp3xxx_wdt_ioctl,
194	.open = stmp3xxx_wdt_open,
195	.release = stmp3xxx_wdt_release,
196	};
197
198	static struct miscdevice stmp3xxx_wdt_miscdev = {
199	.minor = WATCHDOG_MINOR,
200	.name = "watchdog",
201	.fops = &stmp3xxx_wdt_fops,
202	};
203
204	static int __devinit stmp3xxx_wdt_probe(struct platform_device *pdev)
205	{
206	int ret = 0;
207
208	if (heartbeat < 1 \|\| heartbeat > MAX_HEARTBEAT)
209	heartbeat = DEFAULT_HEARTBEAT;
210
211	boot_status = __raw_readl(REGS_RTC_BASE + HW_RTC_PERSISTENT1) &
212	BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER;
213	boot_status = !!boot_status;
214	stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
215	REGS_RTC_BASE + HW_RTC_PERSISTENT1);
216	wdt_disable(); /* disable for now */
217
218	ret = misc_register(&stmp3xxx_wdt_miscdev);
219	if (ret < 0) {
220	dev_err(&pdev->dev, "cannot register misc device\n");
221	return ret;
222	}
223
224	printk(KERN_INFO "stmp3xxx watchdog: initialized, heartbeat %d sec\n",
225	heartbeat);
226
227	return ret;
228	}
229
230	static int __devexit stmp3xxx_wdt_remove(struct platform_device *pdev)
231	{
232	misc_deregister(&stmp3xxx_wdt_miscdev);
233	return 0;
234	}
235
236	#ifdef CONFIG_PM
237	static int wdt_suspended;
238	static u32 wdt_saved_time;
239
240	static int stmp3xxx_wdt_suspend(struct platform_device *pdev,
241	pm_message_t state)
242	{
243	if (__raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) &
244	BM_RTC_CTRL_WATCHDOGEN) {
245	wdt_suspended = 1;
246	wdt_saved_time = __raw_readl(REGS_RTC_BASE + HW_RTC_WATCHDOG);
247	wdt_disable();
248	}
249	return 0;
250	}
251
252	static int stmp3xxx_wdt_resume(struct platform_device *pdev)
253	{
254	if (wdt_suspended) {
255	wdt_enable(wdt_saved_time);
256	wdt_suspended = 0;
257	}
258	return 0;
259	}
260	#else
261	#define stmp3xxx_wdt_suspend NULL
262	#define stmp3xxx_wdt_resume NULL
263	#endif
264
265	static struct platform_driver platform_wdt_driver = {
266	.driver = {
267	.name = "stmp3xxx_wdt",
268	},
269	.probe = stmp3xxx_wdt_probe,
270	.remove = __devexit_p(stmp3xxx_wdt_remove),
271	.suspend = stmp3xxx_wdt_suspend,
272	.resume = stmp3xxx_wdt_resume,
273	};
274
275	static int __init stmp3xxx_wdt_init(void)
276	{
277	return platform_driver_register(&platform_wdt_driver);
278	}
279
280	static void __exit stmp3xxx_wdt_exit(void)
281	{
282	return platform_driver_unregister(&platform_wdt_driver);
283	}
284
285	module_init(stmp3xxx_wdt_init);
286	module_exit(stmp3xxx_wdt_exit);
287
288	MODULE_DESCRIPTION("STMP3XXX Watchdog Driver");
289	MODULE_LICENSE("GPL");
290
291	module_param(heartbeat, int, 0);
292	MODULE_PARM_DESC(heartbeat,
293	"Watchdog heartbeat period in seconds from 1 to "
294	__MODULE_STRING(MAX_HEARTBEAT) ", default "
295	__MODULE_STRING(DEFAULT_HEARTBEAT));
296
297	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);