[net-next-2.6.git] / drivers / watchdog / mv64x60_wdt.c

/*
 * mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface
 *
 * Author: James Chapman <jchapman@katalix.com>
 *
 * Platform-specific setup code should configure the dog to generate
 * interrupt or reset as required.  This code only enables/disables
 * and services the watchdog.
 *
 * Derived from mpc8xx_wdt.c, with the following copyright.
 * 
 * 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
 * the terms of the GNU General Public License version 2. This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */

#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>

#include <linux/mv643xx.h>
#include <asm/uaccess.h>
#include <asm/io.h>

#define MV64x60_WDT_WDC_OFFSET	0

/*
 * The watchdog configuration register contains a pair of 2-bit fields,
 *   1.  a reload field, bits 27-26, which triggers a reload of
 *       the countdown register, and
 *   2.  an enable field, bits 25-24, which toggles between
 *       enabling and disabling the watchdog timer.
 * Bit 31 is a read-only field which indicates whether the
 * watchdog timer is currently enabled.
 *
 * The low 24 bits contain the timer reload value.
 */
#define MV64x60_WDC_ENABLE_SHIFT	24
#define MV64x60_WDC_SERVICE_SHIFT	26
#define MV64x60_WDC_ENABLED_SHIFT	31

#define MV64x60_WDC_ENABLED_TRUE	1
#define MV64x60_WDC_ENABLED_FALSE	0

/* Flags bits */
#define MV64x60_WDOG_FLAG_OPENED	0

static unsigned long wdt_flags;
static int wdt_status;
static void __iomem *mv64x60_wdt_regs;
static int mv64x60_wdt_timeout;
static int mv64x60_wdt_count;
static unsigned int bus_clk;
static char expect_close;
static DEFINE_SPINLOCK(mv64x60_wdt_spinlock);

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) ")");

static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift)
{
	u32 data;
	u32 enabled;
	int ret = 0;

	spin_lock(&mv64x60_wdt_spinlock);
	data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1;

	/* only toggle the requested field if enabled state matches predicate */
	if ((enabled ^ enabled_predicate) == 0) {
		/* We write a 1, then a 2 -- to the appropriate field */
		data = (1 << field_shift) | mv64x60_wdt_count;
		writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);

		data = (2 << field_shift) | mv64x60_wdt_count;
		writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
		ret = 1;
	}
	spin_unlock(&mv64x60_wdt_spinlock);

	return ret;
}

static void mv64x60_wdt_service(void)
{
	mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
			       MV64x60_WDC_SERVICE_SHIFT);
}

static void mv64x60_wdt_handler_enable(void)
{
	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE,
				   MV64x60_WDC_ENABLE_SHIFT)) {
		mv64x60_wdt_service();
		printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
	}
}

static void mv64x60_wdt_handler_disable(void)
{
	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
				   MV64x60_WDC_ENABLE_SHIFT))
		printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
}

static void mv64x60_wdt_set_timeout(unsigned int timeout)
{
	/* maximum bus cycle count is 0xFFFFFFFF */
	if (timeout > 0xFFFFFFFF / bus_clk)
		timeout = 0xFFFFFFFF / bus_clk;

	mv64x60_wdt_count = timeout * bus_clk >> 8;
	mv64x60_wdt_timeout = timeout;
}

static int mv64x60_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	mv64x60_wdt_handler_enable();

	return nonseekable_open(inode, file);
}

static int mv64x60_wdt_release(struct inode *inode, struct file *file)
{
	if (expect_close == 42)
		mv64x60_wdt_handler_disable();
	else {
		printk(KERN_CRIT
		       "mv64x60_wdt: unexpected close, not stopping timer!\n");
		mv64x60_wdt_service();
	}
	expect_close = 0;

	clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);

	return 0;
}

static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
				 size_t len, loff_t * ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			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;
			}
		}
		mv64x60_wdt_service();
	}

	return len;
}

static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
			     unsigned int cmd, unsigned long arg)
{
	int timeout;
	int options;
	void __user *argp = (void __user *)arg;
	static struct watchdog_info info = {
		.options =	WDIOF_SETTIMEOUT	|
				WDIOF_MAGICCLOSE	|
				WDIOF_KEEPALIVEPING,
		.firmware_version = 0,
		.identity = "MV64x60 watchdog",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &info, sizeof(info)))
			return -EFAULT;
		break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		if (put_user(wdt_status, (int __user *)argp))
			return -EFAULT;
		wdt_status &= ~WDIOF_KEEPALIVEPING;
		break;

	case WDIOC_GETTEMP:
		return -EOPNOTSUPP;

	case WDIOC_SETOPTIONS:
		if (get_user(options, (int __user *)argp))
			return -EFAULT;

		if (options & WDIOS_DISABLECARD)
			mv64x60_wdt_handler_disable();

		if (options & WDIOS_ENABLECARD)
			mv64x60_wdt_handler_enable();
		break;

	case WDIOC_KEEPALIVE:
		mv64x60_wdt_service();
		wdt_status |= WDIOF_KEEPALIVEPING;
		break;

	case WDIOC_SETTIMEOUT:
		if (get_user(timeout, (int __user *)argp))
			return -EFAULT;
		mv64x60_wdt_set_timeout(timeout);
		/* Fall through */

	case WDIOC_GETTIMEOUT:
		if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
			return -EFAULT;
		break;

	default:
		return -ENOTTY;
	}

	return 0;
}

static const struct file_operations mv64x60_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = mv64x60_wdt_write,
	.ioctl = mv64x60_wdt_ioctl,
	.open = mv64x60_wdt_open,
	.release = mv64x60_wdt_release,
};

static struct miscdevice mv64x60_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &mv64x60_wdt_fops,
};

static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
{
	struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
	struct resource *r;
	int timeout = 10;

	bus_clk = 133;			/* in MHz */
	if (pdata) {
		timeout = pdata->timeout;
		bus_clk = pdata->bus_clk;
	}

	/* Since bus_clk is truncated MHz, actual frequency could be
	 * up to 1MHz higher.  Round up, since it's better to time out
	 * too late than too soon.
	 */
	bus_clk++;
	bus_clk *= 1000000;		/* convert to Hz */

	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
	if (!r)
		return -ENODEV;

	mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1);
	if (mv64x60_wdt_regs == NULL)
		return -ENOMEM;

	mv64x60_wdt_set_timeout(timeout);

	mv64x60_wdt_handler_disable();	/* in case timer was already running */

	return misc_register(&mv64x60_wdt_miscdev);
}

static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
{
	misc_deregister(&mv64x60_wdt_miscdev);

	mv64x60_wdt_handler_disable();

	iounmap(mv64x60_wdt_regs);

	return 0;
}

static struct platform_driver mv64x60_wdt_driver = {
	.probe = mv64x60_wdt_probe,
	.remove = __devexit_p(mv64x60_wdt_remove),
	.driver = {
		.owner = THIS_MODULE,
		.name = MV64x60_WDT_NAME,
	},
};

static int __init mv64x60_wdt_init(void)
{
	printk(KERN_INFO "MV64x60 watchdog driver\n");

	return platform_driver_register(&mv64x60_wdt_driver);
}

static void __exit mv64x60_wdt_exit(void)
{
	platform_driver_unregister(&mv64x60_wdt_driver);
}

module_init(mv64x60_wdt_init);
module_exit(mv64x60_wdt_exit);

MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
MODULE_DESCRIPTION("MV64x60 watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
3be10211 JC	1	/*
	2	* mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface
	3	*
	4	* Author: James Chapman <jchapman@katalix.com>
	5	*
	6	* Platform-specific setup code should configure the dog to generate
	7	* interrupt or reset as required. This code only enables/disables
	8	* and services the watchdog.
	9	*
	10	* Derived from mpc8xx_wdt.c, with the following copyright.
	11	*
	12	* 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
	13	* the terms of the GNU General Public License version 2. This program
	14	* is licensed "as is" without any warranty of any kind, whether express
	15	* or implied.
	16	*/
	17
3be10211 JC	18	#include <linux/fs.h>
	19	#include <linux/init.h>
	20	#include <linux/kernel.h>
	21	#include <linux/miscdevice.h>
	22	#include <linux/module.h>
	23	#include <linux/watchdog.h>
d052d1be RK	24	#include <linux/platform_device.h>
d052d1be RK	25
7e07a159	26	#include <linux/mv643xx.h>
3be10211 JC	27	#include <asm/uaccess.h>
	28	#include <asm/io.h>
	29
8a5cfa64 DF	30	#define MV64x60_WDT_WDC_OFFSET 0
8a5cfa64 DF	31
f1869994 DF	32	/*
	33	* The watchdog configuration register contains a pair of 2-bit fields,
	34	* 1. a reload field, bits 27-26, which triggers a reload of
	35	* the countdown register, and
	36	* 2. an enable field, bits 25-24, which toggles between
	37	* enabling and disabling the watchdog timer.
	38	* Bit 31 is a read-only field which indicates whether the
	39	* watchdog timer is currently enabled.
	40	*
	41	* The low 24 bits contain the timer reload value.
	42	*/
	43	#define MV64x60_WDC_ENABLE_SHIFT 24
	44	#define MV64x60_WDC_SERVICE_SHIFT 26
	45	#define MV64x60_WDC_ENABLED_SHIFT 31
	46
	47	#define MV64x60_WDC_ENABLED_TRUE 1
	48	#define MV64x60_WDC_ENABLED_FALSE 0
3be10211 JC	49
	50	/* Flags bits */
	51	#define MV64x60_WDOG_FLAG_OPENED 0
3be10211 JC	52
	53	static unsigned long wdt_flags;
	54	static int wdt_status;
8a5cfa64	55	static void __iomem *mv64x60_wdt_regs;
3be10211	56	static int mv64x60_wdt_timeout;
f1869994	57	static int mv64x60_wdt_count;
94796f90	58	static unsigned int bus_clk;
bf2fc92c	59	static char expect_close;
f1869994	60	static DEFINE_SPINLOCK(mv64x60_wdt_spinlock);
3be10211	61
d37a5c3d DF	62	static int nowayout = WATCHDOG_NOWAYOUT;
	63	module_param(nowayout, int, 0);
	64	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	65
f1869994	66	static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift)
3be10211	67	{
f1869994 DF	68	u32 data;
	69	u32 enabled;
	70	int ret = 0;
	71
	72	spin_lock(&mv64x60_wdt_spinlock);
	73	data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	74	enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1;
	75
	76	/* only toggle the requested field if enabled state matches predicate */
	77	if ((enabled ^ enabled_predicate) == 0) {
	78	/* We write a 1, then a 2 -- to the appropriate field */
	79	data = (1 << field_shift) \| mv64x60_wdt_count;
	80	writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	81
	82	data = (2 << field_shift) \| mv64x60_wdt_count;
	83	writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	84	ret = 1;
	85	}
	86	spin_unlock(&mv64x60_wdt_spinlock);
	87
	88	return ret;
3be10211 JC	89	}
	90
	91	static void mv64x60_wdt_service(void)
	92	{
f1869994 DF	93	mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
f1869994 DF	94	MV64x60_WDC_SERVICE_SHIFT);
3be10211 JC	95	}
3be10211 JC	96
f1869994	97	static void mv64x60_wdt_handler_enable(void)
3be10211	98	{
f1869994 DF	99	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE,
	100	MV64x60_WDC_ENABLE_SHIFT)) {
	101	mv64x60_wdt_service();
	102	printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
3be10211 JC	103	}
	104	}
	105
f1869994	106	static void mv64x60_wdt_handler_disable(void)
3be10211	107	{
f1869994 DF	108	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
	109	MV64x60_WDC_ENABLE_SHIFT))
	110	printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
3be10211 JC	111	}
3be10211 JC	112
f1869994	113	static void mv64x60_wdt_set_timeout(unsigned int timeout)
94796f90 DF	114	{
	115	/* maximum bus cycle count is 0xFFFFFFFF */
	116	if (timeout > 0xFFFFFFFF / bus_clk)
	117	timeout = 0xFFFFFFFF / bus_clk;
	118
f1869994	119	mv64x60_wdt_count = timeout * bus_clk >> 8;
94796f90	120	mv64x60_wdt_timeout = timeout;
94796f90 DF	121	}
94796f90 DF	122
3be10211 JC	123	static int mv64x60_wdt_open(struct inode inode, struct file file)
	124	{
	125	if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
	126	return -EBUSY;
	127
d37a5c3d DF	128	if (nowayout)
	129	__module_get(THIS_MODULE);
	130
3be10211 JC	131	mv64x60_wdt_handler_enable();
3be10211 JC	132
861e5137	133	return nonseekable_open(inode, file);
3be10211 JC	134	}
	135
	136	static int mv64x60_wdt_release(struct inode inode, struct file file)
	137	{
bf2fc92c	138	if (expect_close == 42)
d37a5c3d	139	mv64x60_wdt_handler_disable();
bf2fc92c DF	140	else {
	141	printk(KERN_CRIT
	142	"mv64x60_wdt: unexpected close, not stopping timer!\n");
	143	mv64x60_wdt_service();
	144	}
	145	expect_close = 0;
3be10211 JC	146
	147	clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
	148
	149	return 0;
	150	}
	151
b2846dfa	152	static ssize_t mv64x60_wdt_write(struct file file, const char __user data,
3be10211 JC	153	size_t len, loff_t * ppos)
3be10211 JC	154	{
bf2fc92c DF	155	if (len) {
	156	if (!nowayout) {
	157	size_t i;
	158
	159	expect_close = 0;
	160
	161	for (i = 0; i != len; i++) {
	162	char c;
	163	if(get_user(c, data + i))
	164	return -EFAULT;
	165	if (c == 'V')
	166	expect_close = 42;
	167	}
	168	}
3be10211	169	mv64x60_wdt_service();
bf2fc92c	170	}
3be10211 JC	171
	172	return len;
	173	}
	174
	175	static int mv64x60_wdt_ioctl(struct inode inode, struct file file,
	176	unsigned int cmd, unsigned long arg)
	177	{
94796f90	178	int timeout;
85d57238	179	int options;
b2846dfa	180	void __user argp = (void __user )arg;
3be10211	181	static struct watchdog_info info = {
94796f90	182	.options = WDIOF_SETTIMEOUT \|
bf2fc92c	183	WDIOF_MAGICCLOSE \|
94796f90	184	WDIOF_KEEPALIVEPING,
3be10211 JC	185	.firmware_version = 0,
	186	.identity = "MV64x60 watchdog",
	187	};
	188
	189	switch (cmd) {
	190	case WDIOC_GETSUPPORT:
b2846dfa	191	if (copy_to_user(argp, &info, sizeof(info)))
3be10211 JC	192	return -EFAULT;
	193	break;
	194
	195	case WDIOC_GETSTATUS:
	196	case WDIOC_GETBOOTSTATUS:
b2846dfa	197	if (put_user(wdt_status, (int __user *)argp))
3be10211 JC	198	return -EFAULT;
	199	wdt_status &= ~WDIOF_KEEPALIVEPING;
	200	break;
	201
	202	case WDIOC_GETTEMP:
	203	return -EOPNOTSUPP;
	204
	205	case WDIOC_SETOPTIONS:
85d57238 DF	206	if (get_user(options, (int __user *)argp))
	207	return -EFAULT;
	208
	209	if (options & WDIOS_DISABLECARD)
	210	mv64x60_wdt_handler_disable();
	211
	212	if (options & WDIOS_ENABLECARD)
	213	mv64x60_wdt_handler_enable();
	214	break;
3be10211 JC	215
	216	case WDIOC_KEEPALIVE:
	217	mv64x60_wdt_service();
	218	wdt_status \|= WDIOF_KEEPALIVEPING;
	219	break;
	220
	221	case WDIOC_SETTIMEOUT:
94796f90 DF	222	if (get_user(timeout, (int __user *)argp))
	223	return -EFAULT;
	224	mv64x60_wdt_set_timeout(timeout);
	225	/* Fall through */
3be10211 JC	226
3be10211 JC	227	case WDIOC_GETTIMEOUT:
264f0991	228	if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
3be10211 JC	229	return -EFAULT;
	230	break;
	231
	232	default:
795b89d2	233	return -ENOTTY;
3be10211 JC	234	}
	235
	236	return 0;
	237	}
	238
62322d25	239	static const struct file_operations mv64x60_wdt_fops = {
3be10211 JC	240	.owner = THIS_MODULE,
	241	.llseek = no_llseek,
	242	.write = mv64x60_wdt_write,
	243	.ioctl = mv64x60_wdt_ioctl,
	244	.open = mv64x60_wdt_open,
	245	.release = mv64x60_wdt_release,
	246	};
	247
	248	static struct miscdevice mv64x60_wdt_miscdev = {
	249	.minor = WATCHDOG_MINOR,
	250	.name = "watchdog",
	251	.fops = &mv64x60_wdt_fops,
	252	};
	253
3ae5eaec	254	static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
3be10211	255	{
3ae5eaec	256	struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
8a5cfa64	257	struct resource *r;
94796f90	258	int timeout = 10;
3be10211	259
94796f90	260	bus_clk = 133; /* in MHz */
3be10211	261	if (pdata) {
94796f90	262	timeout = pdata->timeout;
3be10211 JC	263	bus_clk = pdata->bus_clk;
	264	}
	265
94796f90 DF	266	/* Since bus_clk is truncated MHz, actual frequency could be
	267	* up to 1MHz higher. Round up, since it's better to time out
	268	* too late than too soon.
	269	*/
	270	bus_clk++;
	271	bus_clk = 1000000; / convert to Hz */
	272
8a5cfa64 DF	273	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
	274	if (!r)
	275	return -ENODEV;
	276
	277	mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1);
	278	if (mv64x60_wdt_regs == NULL)
	279	return -ENOMEM;
3be10211	280
94796f90	281	mv64x60_wdt_set_timeout(timeout);
3be10211	282
2422df5e DF	283	mv64x60_wdt_handler_disable(); /* in case timer was already running */
2422df5e DF	284
3be10211 JC	285	return misc_register(&mv64x60_wdt_miscdev);
	286	}
	287
3ae5eaec	288	static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
3be10211 JC	289	{
	290	misc_deregister(&mv64x60_wdt_miscdev);
	291
3be10211 JC	292	mv64x60_wdt_handler_disable();
3be10211 JC	293
8a5cfa64 DF	294	iounmap(mv64x60_wdt_regs);
8a5cfa64 DF	295
3be10211 JC	296	return 0;
	297	}
	298
3ae5eaec	299	static struct platform_driver mv64x60_wdt_driver = {
3be10211 JC	300	.probe = mv64x60_wdt_probe,
3be10211 JC	301	.remove = __devexit_p(mv64x60_wdt_remove),
3ae5eaec RK	302	.driver = {
	303	.owner = THIS_MODULE,
	304	.name = MV64x60_WDT_NAME,
	305	},
3be10211 JC	306	};
3be10211 JC	307
3be10211 JC	308	static int __init mv64x60_wdt_init(void)
3be10211 JC	309	{
3be10211 JC	310	printk(KERN_INFO "MV64x60 watchdog driver\n");
3be10211 JC	311
422db8d2	312	return platform_driver_register(&mv64x60_wdt_driver);
3be10211 JC	313	}
	314
	315	static void __exit mv64x60_wdt_exit(void)
	316	{
3ae5eaec	317	platform_driver_unregister(&mv64x60_wdt_driver);
3be10211 JC	318	}
	319
	320	module_init(mv64x60_wdt_init);
	321	module_exit(mv64x60_wdt_exit);
	322
	323	MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
	324	MODULE_DESCRIPTION("MV64x60 watchdog driver");
	325	MODULE_LICENSE("GPL");
	326	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);