[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 <linux/uaccess.h>
#include <linux/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 long mv64x60_wdt_ioctl(struct file *file,
					unsigned int cmd, unsigned long arg)
{
	int timeout;
	int options;
	void __user *argp = (void __user *)arg;
	static const 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,
	.unlocked_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, resource_size(r));
	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);
MODULE_ALIAS("platform:" MV64x60_WDT_NAME);
Commit	Line	Data
	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
	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>
	24	#include <linux/platform_device.h>
	25	#include <linux/mv643xx.h>
	26	#include <linux/uaccess.h>
	27	#include <linux/io.h>
	28
	29	#define MV64x60_WDT_WDC_OFFSET 0
	30
	31	/*
	32	* The watchdog configuration register contains a pair of 2-bit fields,
	33	* 1. a reload field, bits 27-26, which triggers a reload of
	34	* the countdown register, and
	35	* 2. an enable field, bits 25-24, which toggles between
	36	* enabling and disabling the watchdog timer.
	37	* Bit 31 is a read-only field which indicates whether the
	38	* watchdog timer is currently enabled.
	39	*
	40	* The low 24 bits contain the timer reload value.
	41	*/
	42	#define MV64x60_WDC_ENABLE_SHIFT 24
	43	#define MV64x60_WDC_SERVICE_SHIFT 26
	44	#define MV64x60_WDC_ENABLED_SHIFT 31
	45
	46	#define MV64x60_WDC_ENABLED_TRUE 1
	47	#define MV64x60_WDC_ENABLED_FALSE 0
	48
	49	/* Flags bits */
	50	#define MV64x60_WDOG_FLAG_OPENED 0
	51
	52	static unsigned long wdt_flags;
	53	static int wdt_status;
	54	static void __iomem *mv64x60_wdt_regs;
	55	static int mv64x60_wdt_timeout;
	56	static int mv64x60_wdt_count;
	57	static unsigned int bus_clk;
	58	static char expect_close;
	59	static DEFINE_SPINLOCK(mv64x60_wdt_spinlock);
	60
	61	static int nowayout = WATCHDOG_NOWAYOUT;
	62	module_param(nowayout, int, 0);
	63	MODULE_PARM_DESC(nowayout,
	64	"Watchdog cannot be stopped once started (default="
	65	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	66
	67	static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift)
	68	{
	69	u32 data;
	70	u32 enabled;
	71	int ret = 0;
	72
	73	spin_lock(&mv64x60_wdt_spinlock);
	74	data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	75	enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1;
	76
	77	/* only toggle the requested field if enabled state matches predicate */
	78	if ((enabled ^ enabled_predicate) == 0) {
	79	/* We write a 1, then a 2 -- to the appropriate field */
	80	data = (1 << field_shift) \| mv64x60_wdt_count;
	81	writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	82
	83	data = (2 << field_shift) \| mv64x60_wdt_count;
	84	writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	85	ret = 1;
	86	}
	87	spin_unlock(&mv64x60_wdt_spinlock);
	88
	89	return ret;
	90	}
	91
	92	static void mv64x60_wdt_service(void)
	93	{
	94	mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
	95	MV64x60_WDC_SERVICE_SHIFT);
	96	}
	97
	98	static void mv64x60_wdt_handler_enable(void)
	99	{
	100	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE,
	101	MV64x60_WDC_ENABLE_SHIFT)) {
	102	mv64x60_wdt_service();
	103	printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
	104	}
	105	}
	106
	107	static void mv64x60_wdt_handler_disable(void)
	108	{
	109	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
	110	MV64x60_WDC_ENABLE_SHIFT))
	111	printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
	112	}
	113
	114	static void mv64x60_wdt_set_timeout(unsigned int timeout)
	115	{
	116	/* maximum bus cycle count is 0xFFFFFFFF */
	117	if (timeout > 0xFFFFFFFF / bus_clk)
	118	timeout = 0xFFFFFFFF / bus_clk;
	119
	120	mv64x60_wdt_count = timeout * bus_clk >> 8;
	121	mv64x60_wdt_timeout = timeout;
	122	}
	123
	124	static int mv64x60_wdt_open(struct inode inode, struct file file)
	125	{
	126	if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
	127	return -EBUSY;
	128
	129	if (nowayout)
	130	__module_get(THIS_MODULE);
	131
	132	mv64x60_wdt_handler_enable();
	133
	134	return nonseekable_open(inode, file);
	135	}
	136
	137	static int mv64x60_wdt_release(struct inode inode, struct file file)
	138	{
	139	if (expect_close == 42)
	140	mv64x60_wdt_handler_disable();
	141	else {
	142	printk(KERN_CRIT
	143	"mv64x60_wdt: unexpected close, not stopping timer!\n");
	144	mv64x60_wdt_service();
	145	}
	146	expect_close = 0;
	147
	148	clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
	149
	150	return 0;
	151	}
	152
	153	static ssize_t mv64x60_wdt_write(struct file file, const char __user data,
	154	size_t len, loff_t *ppos)
	155	{
	156	if (len) {
	157	if (!nowayout) {
	158	size_t i;
	159
	160	expect_close = 0;
	161
	162	for (i = 0; i != len; i++) {
	163	char c;
	164	if (get_user(c, data + i))
	165	return -EFAULT;
	166	if (c == 'V')
	167	expect_close = 42;
	168	}
	169	}
	170	mv64x60_wdt_service();
	171	}
	172
	173	return len;
	174	}
	175
	176	static long mv64x60_wdt_ioctl(struct file *file,
	177	unsigned int cmd, unsigned long arg)
	178	{
	179	int timeout;
	180	int options;
	181	void __user argp = (void __user )arg;
	182	static const struct watchdog_info info = {
	183	.options = WDIOF_SETTIMEOUT \|
	184	WDIOF_MAGICCLOSE \|
	185	WDIOF_KEEPALIVEPING,
	186	.firmware_version = 0,
	187	.identity = "MV64x60 watchdog",
	188	};
	189
	190	switch (cmd) {
	191	case WDIOC_GETSUPPORT:
	192	if (copy_to_user(argp, &info, sizeof(info)))
	193	return -EFAULT;
	194	break;
	195
	196	case WDIOC_GETSTATUS:
	197	case WDIOC_GETBOOTSTATUS:
	198	if (put_user(wdt_status, (int __user *)argp))
	199	return -EFAULT;
	200	wdt_status &= ~WDIOF_KEEPALIVEPING;
	201	break;
	202
	203	case WDIOC_GETTEMP:
	204	return -EOPNOTSUPP;
	205
	206	case WDIOC_SETOPTIONS:
	207	if (get_user(options, (int __user *)argp))
	208	return -EFAULT;
	209
	210	if (options & WDIOS_DISABLECARD)
	211	mv64x60_wdt_handler_disable();
	212
	213	if (options & WDIOS_ENABLECARD)
	214	mv64x60_wdt_handler_enable();
	215	break;
	216
	217	case WDIOC_KEEPALIVE:
	218	mv64x60_wdt_service();
	219	wdt_status \|= WDIOF_KEEPALIVEPING;
	220	break;
	221
	222	case WDIOC_SETTIMEOUT:
	223	if (get_user(timeout, (int __user *)argp))
	224	return -EFAULT;
	225	mv64x60_wdt_set_timeout(timeout);
	226	/* Fall through */
	227
	228	case WDIOC_GETTIMEOUT:
	229	if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
	230	return -EFAULT;
	231	break;
	232
	233	default:
	234	return -ENOTTY;
	235	}
	236
	237	return 0;
	238	}
	239
	240	static const struct file_operations mv64x60_wdt_fops = {
	241	.owner = THIS_MODULE,
	242	.llseek = no_llseek,
	243	.write = mv64x60_wdt_write,
	244	.unlocked_ioctl = mv64x60_wdt_ioctl,
	245	.open = mv64x60_wdt_open,
	246	.release = mv64x60_wdt_release,
	247	};
	248
	249	static struct miscdevice mv64x60_wdt_miscdev = {
	250	.minor = WATCHDOG_MINOR,
	251	.name = "watchdog",
	252	.fops = &mv64x60_wdt_fops,
	253	};
	254
	255	static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
	256	{
	257	struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
	258	struct resource *r;
	259	int timeout = 10;
	260
	261	bus_clk = 133; /* in MHz */
	262	if (pdata) {
	263	timeout = pdata->timeout;
	264	bus_clk = pdata->bus_clk;
	265	}
	266
	267	/* Since bus_clk is truncated MHz, actual frequency could be
	268	* up to 1MHz higher. Round up, since it's better to time out
	269	* too late than too soon.
	270	*/
	271	bus_clk++;
	272	bus_clk = 1000000; / convert to Hz */
	273
	274	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
	275	if (!r)
	276	return -ENODEV;
	277
	278	mv64x60_wdt_regs = ioremap(r->start, resource_size(r));
	279	if (mv64x60_wdt_regs == NULL)
	280	return -ENOMEM;
	281
	282	mv64x60_wdt_set_timeout(timeout);
	283
	284	mv64x60_wdt_handler_disable(); /* in case timer was already running */
	285
	286	return misc_register(&mv64x60_wdt_miscdev);
	287	}
	288
	289	static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
	290	{
	291	misc_deregister(&mv64x60_wdt_miscdev);
	292
	293	mv64x60_wdt_handler_disable();
	294
	295	iounmap(mv64x60_wdt_regs);
	296
	297	return 0;
	298	}
	299
	300	static struct platform_driver mv64x60_wdt_driver = {
	301	.probe = mv64x60_wdt_probe,
	302	.remove = __devexit_p(mv64x60_wdt_remove),
	303	.driver = {
	304	.owner = THIS_MODULE,
	305	.name = MV64x60_WDT_NAME,
	306	},
	307	};
	308
	309	static int __init mv64x60_wdt_init(void)
	310	{
	311	printk(KERN_INFO "MV64x60 watchdog driver\n");
	312
	313	return platform_driver_register(&mv64x60_wdt_driver);
	314	}
	315
	316	static void __exit mv64x60_wdt_exit(void)
	317	{
	318	platform_driver_unregister(&mv64x60_wdt_driver);
	319	}
	320
	321	module_init(mv64x60_wdt_init);
	322	module_exit(mv64x60_wdt_exit);
	323
	324	MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
	325	MODULE_DESCRIPTION("MV64x60 watchdog driver");
	326	MODULE_LICENSE("GPL");
	327	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	328	MODULE_ALIAS("platform:" MV64x60_WDT_NAME);