[mirror_ubuntu-zesty-kernel.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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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 bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 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();
		pr_notice("watchdog activated\n");
	}
}

static void mv64x60_wdt_handler_disable(void)
{
	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
				   MV64x60_WDC_ENABLE_SHIFT))
		pr_notice("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 {
		pr_crit("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 mv64x60_wdt_probe(struct platform_device *dev)
{
	struct mv64x60_wdt_pdata *pdata = dev_get_platdata(&dev->dev);
	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 = devm_ioremap(&dev->dev, 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 mv64x60_wdt_remove(struct platform_device *dev)
{
	misc_deregister(&mv64x60_wdt_miscdev);

	mv64x60_wdt_handler_disable();

	return 0;
}

static struct platform_driver mv64x60_wdt_driver = {
	.probe = mv64x60_wdt_probe,
	.remove = mv64x60_wdt_remove,
	.driver = {
		.name = MV64x60_WDT_NAME,
	},
};

static int __init mv64x60_wdt_init(void)
{
	pr_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("platform:" MV64x60_WDT_NAME);
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.
a86b8498	11	*
3be10211 JC	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
27c766aa JP	18	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	19
3be10211 JC	20	#include <linux/fs.h>
	21	#include <linux/init.h>
	22	#include <linux/kernel.h>
	23	#include <linux/miscdevice.h>
	24	#include <linux/module.h>
	25	#include <linux/watchdog.h>
d052d1be	26	#include <linux/platform_device.h>
7e07a159	27	#include <linux/mv643xx.h>
a86b8498 AC	28	#include <linux/uaccess.h>
a86b8498 AC	29	#include <linux/io.h>
3be10211	30
8a5cfa64 DF	31	#define MV64x60_WDT_WDC_OFFSET 0
8a5cfa64 DF	32
f1869994 DF	33	/*
	34	* The watchdog configuration register contains a pair of 2-bit fields,
	35	* 1. a reload field, bits 27-26, which triggers a reload of
	36	* the countdown register, and
	37	* 2. an enable field, bits 25-24, which toggles between
	38	* enabling and disabling the watchdog timer.
	39	* Bit 31 is a read-only field which indicates whether the
	40	* watchdog timer is currently enabled.
	41	*
	42	* The low 24 bits contain the timer reload value.
	43	*/
	44	#define MV64x60_WDC_ENABLE_SHIFT 24
	45	#define MV64x60_WDC_SERVICE_SHIFT 26
	46	#define MV64x60_WDC_ENABLED_SHIFT 31
	47
	48	#define MV64x60_WDC_ENABLED_TRUE 1
	49	#define MV64x60_WDC_ENABLED_FALSE 0
3be10211 JC	50
	51	/* Flags bits */
	52	#define MV64x60_WDOG_FLAG_OPENED 0
3be10211 JC	53
	54	static unsigned long wdt_flags;
	55	static int wdt_status;
8a5cfa64	56	static void __iomem *mv64x60_wdt_regs;
3be10211	57	static int mv64x60_wdt_timeout;
f1869994	58	static int mv64x60_wdt_count;
94796f90	59	static unsigned int bus_clk;
bf2fc92c	60	static char expect_close;
f1869994	61	static DEFINE_SPINLOCK(mv64x60_wdt_spinlock);
3be10211	62
86a1e189 WVS	63	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	64	module_param(nowayout, bool, 0);
a86b8498 AC	65	MODULE_PARM_DESC(nowayout,
	66	"Watchdog cannot be stopped once started (default="
	67	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
d37a5c3d	68
f1869994	69	static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift)
3be10211	70	{
f1869994 DF	71	u32 data;
	72	u32 enabled;
	73	int ret = 0;
	74
	75	spin_lock(&mv64x60_wdt_spinlock);
	76	data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	77	enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1;
	78
	79	/* only toggle the requested field if enabled state matches predicate */
	80	if ((enabled ^ enabled_predicate) == 0) {
	81	/* We write a 1, then a 2 -- to the appropriate field */
	82	data = (1 << field_shift) \| mv64x60_wdt_count;
	83	writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	84
	85	data = (2 << field_shift) \| mv64x60_wdt_count;
	86	writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
	87	ret = 1;
	88	}
	89	spin_unlock(&mv64x60_wdt_spinlock);
	90
	91	return ret;
3be10211 JC	92	}
	93
	94	static void mv64x60_wdt_service(void)
	95	{
f1869994 DF	96	mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
f1869994 DF	97	MV64x60_WDC_SERVICE_SHIFT);
3be10211 JC	98	}
3be10211 JC	99
f1869994	100	static void mv64x60_wdt_handler_enable(void)
3be10211	101	{
f1869994 DF	102	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE,
	103	MV64x60_WDC_ENABLE_SHIFT)) {
	104	mv64x60_wdt_service();
27c766aa	105	pr_notice("watchdog activated\n");
3be10211 JC	106	}
	107	}
	108
f1869994	109	static void mv64x60_wdt_handler_disable(void)
3be10211	110	{
f1869994 DF	111	if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
f1869994 DF	112	MV64x60_WDC_ENABLE_SHIFT))
27c766aa	113	pr_notice("watchdog deactivated\n");
3be10211 JC	114	}
3be10211 JC	115
f1869994	116	static void mv64x60_wdt_set_timeout(unsigned int timeout)
94796f90 DF	117	{
	118	/* maximum bus cycle count is 0xFFFFFFFF */
	119	if (timeout > 0xFFFFFFFF / bus_clk)
	120	timeout = 0xFFFFFFFF / bus_clk;
	121
f1869994	122	mv64x60_wdt_count = timeout * bus_clk >> 8;
94796f90	123	mv64x60_wdt_timeout = timeout;
94796f90 DF	124	}
94796f90 DF	125
3be10211 JC	126	static int mv64x60_wdt_open(struct inode inode, struct file file)
	127	{
	128	if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
	129	return -EBUSY;
	130
d37a5c3d DF	131	if (nowayout)
	132	__module_get(THIS_MODULE);
	133
3be10211 JC	134	mv64x60_wdt_handler_enable();
3be10211 JC	135
861e5137	136	return nonseekable_open(inode, file);
3be10211 JC	137	}
	138
	139	static int mv64x60_wdt_release(struct inode inode, struct file file)
	140	{
bf2fc92c	141	if (expect_close == 42)
d37a5c3d	142	mv64x60_wdt_handler_disable();
bf2fc92c	143	else {
27c766aa	144	pr_crit("unexpected close, not stopping timer!\n");
bf2fc92c DF	145	mv64x60_wdt_service();
	146	}
	147	expect_close = 0;
3be10211 JC	148
	149	clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
	150
	151	return 0;
	152	}
	153
b2846dfa	154	static ssize_t mv64x60_wdt_write(struct file file, const char __user data,
a86b8498	155	size_t len, loff_t *ppos)
3be10211	156	{
bf2fc92c DF	157	if (len) {
	158	if (!nowayout) {
	159	size_t i;
	160
	161	expect_close = 0;
	162
	163	for (i = 0; i != len; i++) {
	164	char c;
a86b8498	165	if (get_user(c, data + i))
bf2fc92c DF	166	return -EFAULT;
	167	if (c == 'V')
	168	expect_close = 42;
	169	}
	170	}
3be10211	171	mv64x60_wdt_service();
bf2fc92c	172	}
3be10211 JC	173
	174	return len;
	175	}
	176
a86b8498 AC	177	static long mv64x60_wdt_ioctl(struct file *file,
a86b8498 AC	178	unsigned int cmd, unsigned long arg)
3be10211	179	{
94796f90	180	int timeout;
85d57238	181	int options;
b2846dfa	182	void __user argp = (void __user )arg;
42747d71	183	static const struct watchdog_info info = {
94796f90	184	.options = WDIOF_SETTIMEOUT \|
bf2fc92c	185	WDIOF_MAGICCLOSE \|
94796f90	186	WDIOF_KEEPALIVEPING,
3be10211 JC	187	.firmware_version = 0,
	188	.identity = "MV64x60 watchdog",
	189	};
	190
	191	switch (cmd) {
	192	case WDIOC_GETSUPPORT:
b2846dfa	193	if (copy_to_user(argp, &info, sizeof(info)))
3be10211 JC	194	return -EFAULT;
	195	break;
	196
	197	case WDIOC_GETSTATUS:
	198	case WDIOC_GETBOOTSTATUS:
b2846dfa	199	if (put_user(wdt_status, (int __user *)argp))
3be10211 JC	200	return -EFAULT;
	201	wdt_status &= ~WDIOF_KEEPALIVEPING;
	202	break;
	203
	204	case WDIOC_GETTEMP:
	205	return -EOPNOTSUPP;
	206
	207	case WDIOC_SETOPTIONS:
85d57238 DF	208	if (get_user(options, (int __user *)argp))
	209	return -EFAULT;
	210
	211	if (options & WDIOS_DISABLECARD)
	212	mv64x60_wdt_handler_disable();
	213
	214	if (options & WDIOS_ENABLECARD)
	215	mv64x60_wdt_handler_enable();
	216	break;
3be10211 JC	217
	218	case WDIOC_KEEPALIVE:
	219	mv64x60_wdt_service();
	220	wdt_status \|= WDIOF_KEEPALIVEPING;
	221	break;
	222
	223	case WDIOC_SETTIMEOUT:
94796f90 DF	224	if (get_user(timeout, (int __user *)argp))
	225	return -EFAULT;
	226	mv64x60_wdt_set_timeout(timeout);
	227	/* Fall through */
3be10211 JC	228
3be10211 JC	229	case WDIOC_GETTIMEOUT:
264f0991	230	if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
3be10211 JC	231	return -EFAULT;
	232	break;
	233
	234	default:
795b89d2	235	return -ENOTTY;
3be10211 JC	236	}
	237
	238	return 0;
	239	}
	240
62322d25	241	static const struct file_operations mv64x60_wdt_fops = {
3be10211 JC	242	.owner = THIS_MODULE,
	243	.llseek = no_llseek,
	244	.write = mv64x60_wdt_write,
a86b8498	245	.unlocked_ioctl = mv64x60_wdt_ioctl,
3be10211 JC	246	.open = mv64x60_wdt_open,
	247	.release = mv64x60_wdt_release,
	248	};
	249
	250	static struct miscdevice mv64x60_wdt_miscdev = {
	251	.minor = WATCHDOG_MINOR,
	252	.name = "watchdog",
	253	.fops = &mv64x60_wdt_fops,
	254	};
	255
2d991a16	256	static int mv64x60_wdt_probe(struct platform_device *dev)
3be10211	257	{
bc8fdfbe	258	struct mv64x60_wdt_pdata *pdata = dev_get_platdata(&dev->dev);
8a5cfa64	259	struct resource *r;
94796f90	260	int timeout = 10;
3be10211	261
94796f90	262	bus_clk = 133; /* in MHz */
3be10211	263	if (pdata) {
94796f90	264	timeout = pdata->timeout;
3be10211 JC	265	bus_clk = pdata->bus_clk;
	266	}
	267
94796f90 DF	268	/* Since bus_clk is truncated MHz, actual frequency could be
	269	* up to 1MHz higher. Round up, since it's better to time out
	270	* too late than too soon.
	271	*/
	272	bus_clk++;
	273	bus_clk = 1000000; / convert to Hz */
	274
8a5cfa64 DF	275	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
	276	if (!r)
	277	return -ENODEV;
	278
ac1bb694	279	mv64x60_wdt_regs = devm_ioremap(&dev->dev, r->start, resource_size(r));
8a5cfa64 DF	280	if (mv64x60_wdt_regs == NULL)
8a5cfa64 DF	281	return -ENOMEM;
3be10211	282
94796f90	283	mv64x60_wdt_set_timeout(timeout);
3be10211	284
2422df5e DF	285	mv64x60_wdt_handler_disable(); /* in case timer was already running */
2422df5e DF	286
3be10211 JC	287	return misc_register(&mv64x60_wdt_miscdev);
	288	}
	289
4b12b896	290	static int mv64x60_wdt_remove(struct platform_device *dev)
3be10211 JC	291	{
	292	misc_deregister(&mv64x60_wdt_miscdev);
	293
3be10211 JC	294	mv64x60_wdt_handler_disable();
	295
	296	return 0;
	297	}
	298
3ae5eaec	299	static struct platform_driver mv64x60_wdt_driver = {
3be10211	300	.probe = mv64x60_wdt_probe,
82268714	301	.remove = mv64x60_wdt_remove,
3ae5eaec	302	.driver = {
3ae5eaec RK	303	.name = MV64x60_WDT_NAME,
3ae5eaec RK	304	},
3be10211 JC	305	};
3be10211 JC	306
3be10211 JC	307	static int __init mv64x60_wdt_init(void)
3be10211 JC	308	{
27c766aa	309	pr_info("MV64x60 watchdog driver\n");
3be10211	310
422db8d2	311	return platform_driver_register(&mv64x60_wdt_driver);
3be10211 JC	312	}
	313
	314	static void __exit mv64x60_wdt_exit(void)
	315	{
3ae5eaec	316	platform_driver_unregister(&mv64x60_wdt_driver);
3be10211 JC	317	}
	318
	319	module_init(mv64x60_wdt_init);
	320	module_exit(mv64x60_wdt_exit);
	321
	322	MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
	323	MODULE_DESCRIPTION("MV64x60 watchdog driver");
	324	MODULE_LICENSE("GPL");
f37d193c	325	MODULE_ALIAS("platform:" MV64x60_WDT_NAME);