[linux.git] / drivers / watchdog / sbc7240_wdt.c

/*
 *	NANO7240 SBC Watchdog device driver
 *
 *	Based on w83877f.c by Scott Jennings,
 *
 *	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;
 *
 *	Software distributed under the License is distributed on an "AS IS"
 *	basis, WITHOUT WARRANTY OF ANY KIND, either express or
 *	implied. See the License for the specific language governing
 *	rights and limitations under the License.
 *
 *	(c) Copyright 2007  Gilles GIGAN <[email protected]>
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/fs.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/atomic.h>

#define SBC7240_ENABLE_PORT		0x443
#define SBC7240_DISABLE_PORT		0x043
#define SBC7240_SET_TIMEOUT_PORT	SBC7240_ENABLE_PORT
#define SBC7240_MAGIC_CHAR		'V'

#define SBC7240_TIMEOUT		30
#define SBC7240_MAX_TIMEOUT		255
static int timeout = SBC7240_TIMEOUT;	/* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
		 __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
		 __MODULE_STRING(SBC7240_TIMEOUT) ")");

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");

#define SBC7240_OPEN_STATUS_BIT		0
#define SBC7240_ENABLED_STATUS_BIT	1
#define SBC7240_EXPECT_CLOSE_STATUS_BIT	2
static unsigned long wdt_status;

/*
 * Utility routines
 */

static void wdt_disable(void)
{
	/* disable the watchdog */
	if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
		inb_p(SBC7240_DISABLE_PORT);
		pr_info("Watchdog timer is now disabled\n");
	}
}

static void wdt_enable(void)
{
	/* enable the watchdog */
	if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
		inb_p(SBC7240_ENABLE_PORT);
		pr_info("Watchdog timer is now enabled\n");
	}
}

static int wdt_set_timeout(int t)
{
	if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
		pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT);
		return -1;
	}
	/* set the timeout */
	outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
	timeout = t;
	pr_info("timeout set to %d seconds\n", t);
	return 0;
}

/* Whack the dog */
static inline void wdt_keepalive(void)
{
	if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
		inb_p(SBC7240_ENABLE_PORT);
}

/*
 * /dev/watchdog handling
 */
static ssize_t fop_write(struct file *file, const char __user *buf,
			 size_t count, loff_t *ppos)
{
	size_t i;
	char c;

	if (count) {
		if (!nowayout) {
			clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
				&wdt_status);

			/* is there a magic char ? */
			for (i = 0; i != count; i++) {
				if (get_user(c, buf + i))
					return -EFAULT;
				if (c == SBC7240_MAGIC_CHAR) {
					set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
						&wdt_status);
					break;
				}
			}
		}

		wdt_keepalive();
	}

	return count;
}

static int fop_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
		return -EBUSY;

	wdt_enable();

	return nonseekable_open(inode, file);
}

static int fop_close(struct inode *inode, struct file *file)
{
	if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
	    || !nowayout) {
		wdt_disable();
	} else {
		pr_crit("Unexpected close, not stopping watchdog!\n");
		wdt_keepalive();
	}

	clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
	return 0;
}

static const struct watchdog_info ident = {
	.options = WDIOF_KEEPALIVEPING|
		   WDIOF_SETTIMEOUT|
		   WDIOF_MAGICCLOSE,
	.firmware_version = 1,
	.identity = "SBC7240",
};


static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user((void __user *)arg, &ident, sizeof(ident))
						 ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, (int __user *)arg);
	case WDIOC_SETOPTIONS:
	{
		int options;
		int retval = -EINVAL;

		if (get_user(options, (int __user *)arg))
			return -EFAULT;

		if (options & WDIOS_DISABLECARD) {
			wdt_disable();
			retval = 0;
		}

		if (options & WDIOS_ENABLECARD) {
			wdt_enable();
			retval = 0;
		}

		return retval;
	}
	case WDIOC_KEEPALIVE:
		wdt_keepalive();
		return 0;
	case WDIOC_SETTIMEOUT:
	{
		int new_timeout;

		if (get_user(new_timeout, (int __user *)arg))
			return -EFAULT;

		if (wdt_set_timeout(new_timeout))
			return -EINVAL;

		/* Fall through */
	}
	case WDIOC_GETTIMEOUT:
		return put_user(timeout, (int __user *)arg);
	default:
		return -ENOTTY;
	}
}

static const struct file_operations wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = fop_write,
	.open = fop_open,
	.release = fop_close,
	.unlocked_ioctl = fop_ioctl,
};

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

/*
 *	Notifier for system down
 */

static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
			  void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		wdt_disable();
	return NOTIFY_DONE;
}

static struct notifier_block wdt_notifier = {
	.notifier_call = wdt_notify_sys,
};

static void __exit sbc7240_wdt_unload(void)
{
	pr_info("Removing watchdog\n");
	misc_deregister(&wdt_miscdev);

	unregister_reboot_notifier(&wdt_notifier);
	release_region(SBC7240_ENABLE_PORT, 1);
}

static int __init sbc7240_wdt_init(void)
{
	int rc = -EBUSY;

	if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
		pr_err("I/O address 0x%04x already in use\n",
		       SBC7240_ENABLE_PORT);
		rc = -EIO;
		goto err_out;
	}

	/* The IO port 0x043 used to disable the watchdog
	 * is already claimed by the system timer, so we
	 * can't request_region() it ...*/

	if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
		timeout = SBC7240_TIMEOUT;
		pr_info("timeout value must be 1<=x<=%d, using %d\n",
			SBC7240_MAX_TIMEOUT, timeout);
	}
	wdt_set_timeout(timeout);
	wdt_disable();

	rc = register_reboot_notifier(&wdt_notifier);
	if (rc) {
		pr_err("cannot register reboot notifier (err=%d)\n", rc);
		goto err_out_region;
	}

	rc = misc_register(&wdt_miscdev);
	if (rc) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       wdt_miscdev.minor, rc);
		goto err_out_reboot_notifier;
	}

	pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
		nowayout);

	return 0;

err_out_reboot_notifier:
	unregister_reboot_notifier(&wdt_notifier);
err_out_region:
	release_region(SBC7240_ENABLE_PORT, 1);
err_out:
	return rc;
}

module_init(sbc7240_wdt_init);
module_exit(sbc7240_wdt_unload);

MODULE_AUTHOR("Gilles Gigan");
MODULE_DESCRIPTION("Watchdog device driver for single board"
		   " computers EPIC Nano 7240 from iEi");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
c4c28335 GG	1	/*
	2	* NANO7240 SBC Watchdog device driver
	3	*
	4	* Based on w83877f.c by Scott Jennings,
	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;
	9	*
	10	* Software distributed under the License is distributed on an "AS IS"
	11	* basis, WITHOUT WARRANTY OF ANY KIND, either express or
	12	* implied. See the License for the specific language governing
	13	* rights and limitations under the License.
	14	*
	15	* (c) Copyright 2007 Gilles GIGAN <[email protected]>
	16	*
	17	*/
	18
27c766aa JP	19	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	20
c4c28335 GG	21	#include <linux/fs.h>
	22	#include <linux/init.h>
	23	#include <linux/ioport.h>
	24	#include <linux/jiffies.h>
	25	#include <linux/module.h>
	26	#include <linux/moduleparam.h>
	27	#include <linux/miscdevice.h>
	28	#include <linux/notifier.h>
	29	#include <linux/reboot.h>
	30	#include <linux/types.h>
	31	#include <linux/watchdog.h>
619a8a2b AC	32	#include <linux/io.h>
619a8a2b AC	33	#include <linux/uaccess.h>
60063497	34	#include <linux/atomic.h>
c4c28335	35
c4c28335 GG	36	#define SBC7240_ENABLE_PORT 0x443
	37	#define SBC7240_DISABLE_PORT 0x043
	38	#define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT
	39	#define SBC7240_MAGIC_CHAR 'V'
	40
	41	#define SBC7240_TIMEOUT 30
	42	#define SBC7240_MAX_TIMEOUT 255
	43	static int timeout = SBC7240_TIMEOUT; /* in seconds */
	44	module_param(timeout, int, 0);
	45	MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
	46	__MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
	47	__MODULE_STRING(SBC7240_TIMEOUT) ")");
	48
86a1e189 WVS	49	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	50	module_param(nowayout, bool, 0);
c4c28335 GG	51	MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
	52
	53	#define SBC7240_OPEN_STATUS_BIT 0
	54	#define SBC7240_ENABLED_STATUS_BIT 1
	55	#define SBC7240_EXPECT_CLOSE_STATUS_BIT 2
	56	static unsigned long wdt_status;
	57
	58	/*
	59	* Utility routines
	60	*/
	61
	62	static void wdt_disable(void)
	63	{
	64	/* disable the watchdog */
	65	if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
	66	inb_p(SBC7240_DISABLE_PORT);
27c766aa	67	pr_info("Watchdog timer is now disabled\n");
c4c28335 GG	68	}
	69	}
	70
	71	static void wdt_enable(void)
	72	{
	73	/* enable the watchdog */
	74	if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
	75	inb_p(SBC7240_ENABLE_PORT);
27c766aa	76	pr_info("Watchdog timer is now enabled\n");
c4c28335 GG	77	}
	78	}
	79
	80	static int wdt_set_timeout(int t)
	81	{
	82	if (t < 1 \|\| t > SBC7240_MAX_TIMEOUT) {
27c766aa	83	pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT);
c4c28335 GG	84	return -1;
	85	}
	86	/* set the timeout */
	87	outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
	88	timeout = t;
27c766aa	89	pr_info("timeout set to %d seconds\n", t);
c4c28335 GG	90	return 0;
	91	}
	92
	93	/* Whack the dog */
	94	static inline void wdt_keepalive(void)
	95	{
	96	if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
	97	inb_p(SBC7240_ENABLE_PORT);
	98	}
	99
	100	/*
	101	* /dev/watchdog handling
	102	*/
	103	static ssize_t fop_write(struct file file, const char __user buf,
	104	size_t count, loff_t *ppos)
	105	{
	106	size_t i;
	107	char c;
	108
	109	if (count) {
	110	if (!nowayout) {
	111	clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
	112	&wdt_status);
	113
	114	/* is there a magic char ? */
	115	for (i = 0; i != count; i++) {
	116	if (get_user(c, buf + i))
	117	return -EFAULT;
	118	if (c == SBC7240_MAGIC_CHAR) {
	119	set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
	120	&wdt_status);
	121	break;
	122	}
	123	}
	124	}
	125
	126	wdt_keepalive();
	127	}
	128
	129	return count;
	130	}
	131
	132	static int fop_open(struct inode inode, struct file file)
	133	{
	134	if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
	135	return -EBUSY;
	136
	137	wdt_enable();
	138
	139	return nonseekable_open(inode, file);
	140	}
	141
	142	static int fop_close(struct inode inode, struct file file)
	143	{
	144	if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
	145	\|\| !nowayout) {
	146	wdt_disable();
	147	} else {
27c766aa	148	pr_crit("Unexpected close, not stopping watchdog!\n");
c4c28335 GG	149	wdt_keepalive();
	150	}
	151
	152	clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
	153	return 0;
	154	}
	155
619a8a2b	156	static const struct watchdog_info ident = {
c4c28335 GG	157	.options = WDIOF_KEEPALIVEPING\|
	158	WDIOF_SETTIMEOUT\|
	159	WDIOF_MAGICCLOSE,
	160	.firmware_version = 1,
	161	.identity = "SBC7240",
	162	};
	163
	164
619a8a2b	165	static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
c4c28335 GG	166	{
	167	switch (cmd) {
	168	case WDIOC_GETSUPPORT:
619a8a2b AC	169	return copy_to_user((void __user *)arg, &ident, sizeof(ident))
619a8a2b AC	170	? -EFAULT : 0;
c4c28335 GG	171	case WDIOC_GETSTATUS:
	172	case WDIOC_GETBOOTSTATUS:
	173	return put_user(0, (int __user *)arg);
0c06090c WVS	174	case WDIOC_SETOPTIONS:
	175	{
	176	int options;
	177	int retval = -EINVAL;
c4c28335	178
0c06090c WVS	179	if (get_user(options, (int __user *)arg))
0c06090c WVS	180	return -EFAULT;
c4c28335	181
0c06090c WVS	182	if (options & WDIOS_DISABLECARD) {
	183	wdt_disable();
	184	retval = 0;
	185	}
c4c28335	186
0c06090c WVS	187	if (options & WDIOS_ENABLECARD) {
	188	wdt_enable();
	189	retval = 0;
c4c28335	190	}
c4c28335	191
0c06090c WVS	192	return retval;
	193	}
	194	case WDIOC_KEEPALIVE:
	195	wdt_keepalive();
	196	return 0;
	197	case WDIOC_SETTIMEOUT:
	198	{
	199	int new_timeout;
c4c28335	200
0c06090c WVS	201	if (get_user(new_timeout, (int __user *)arg))
0c06090c WVS	202	return -EFAULT;
c4c28335	203
0c06090c WVS	204	if (wdt_set_timeout(new_timeout))
	205	return -EINVAL;
	206
	207	/* Fall through */
	208	}
c4c28335 GG	209	case WDIOC_GETTIMEOUT:
	210	return put_user(timeout, (int __user *)arg);
	211	default:
	212	return -ENOTTY;
	213	}
	214	}
	215
	216	static const struct file_operations wdt_fops = {
	217	.owner = THIS_MODULE,
	218	.llseek = no_llseek,
	219	.write = fop_write,
	220	.open = fop_open,
	221	.release = fop_close,
619a8a2b	222	.unlocked_ioctl = fop_ioctl,
c4c28335 GG	223	};
	224
	225	static struct miscdevice wdt_miscdev = {
	226	.minor = WATCHDOG_MINOR,
	227	.name = "watchdog",
	228	.fops = &wdt_fops,
	229	};
	230
	231	/*
	232	* Notifier for system down
	233	*/
	234
	235	static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
	236	void *unused)
	237	{
	238	if (code == SYS_DOWN \|\| code == SYS_HALT)
	239	wdt_disable();
	240	return NOTIFY_DONE;
	241	}
	242
	243	static struct notifier_block wdt_notifier = {
	244	.notifier_call = wdt_notify_sys,
	245	};
	246
	247	static void __exit sbc7240_wdt_unload(void)
	248	{
27c766aa	249	pr_info("Removing watchdog\n");
c4c28335 GG	250	misc_deregister(&wdt_miscdev);
	251
	252	unregister_reboot_notifier(&wdt_notifier);
	253	release_region(SBC7240_ENABLE_PORT, 1);
	254	}
	255
	256	static int __init sbc7240_wdt_init(void)
	257	{
	258	int rc = -EBUSY;
	259
	260	if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
27c766aa	261	pr_err("I/O address 0x%04x already in use\n",
c4c28335 GG	262	SBC7240_ENABLE_PORT);
	263	rc = -EIO;
	264	goto err_out;
	265	}
	266
	267	/* The IO port 0x043 used to disable the watchdog
	268	* is already claimed by the system timer, so we
25985edc	269	* can't request_region() it ...*/
c4c28335 GG	270
	271	if (timeout < 1 \|\| timeout > SBC7240_MAX_TIMEOUT) {
	272	timeout = SBC7240_TIMEOUT;
27c766aa JP	273	pr_info("timeout value must be 1<=x<=%d, using %d\n",
27c766aa JP	274	SBC7240_MAX_TIMEOUT, timeout);
c4c28335 GG	275	}
	276	wdt_set_timeout(timeout);
	277	wdt_disable();
	278
	279	rc = register_reboot_notifier(&wdt_notifier);
	280	if (rc) {
27c766aa	281	pr_err("cannot register reboot notifier (err=%d)\n", rc);
c4c28335 GG	282	goto err_out_region;
	283	}
	284
	285	rc = misc_register(&wdt_miscdev);
	286	if (rc) {
27c766aa	287	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
c4c28335 GG	288	wdt_miscdev.minor, rc);
	289	goto err_out_reboot_notifier;
	290	}
	291
27c766aa JP	292	pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
27c766aa JP	293	nowayout);
c4c28335 GG	294
	295	return 0;
	296
	297	err_out_reboot_notifier:
	298	unregister_reboot_notifier(&wdt_notifier);
	299	err_out_region:
	300	release_region(SBC7240_ENABLE_PORT, 1);
	301	err_out:
	302	return rc;
	303	}
	304
	305	module_init(sbc7240_wdt_init);
	306	module_exit(sbc7240_wdt_unload);
	307
	308	MODULE_AUTHOR("Gilles Gigan");
	309	MODULE_DESCRIPTION("Watchdog device driver for single board"
	310	" computers EPIC Nano 7240 from iEi");
	311	MODULE_LICENSE("GPL");
	312	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	313