[mirror_ubuntu-jammy-kernel.git] / drivers / watchdog / it8712f_wdt.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	IT8712F "Smart Guardian" Watchdog support
 *
 *	Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
 *
 *	Based on info and code taken from:
 *
 *	drivers/char/watchdog/scx200_wdt.c
 *	drivers/hwmon/it87.c
 *	IT8712F EC-LPC I/O Preliminary Specification 0.8.2
 *	IT8712F EC-LPC I/O Preliminary Specification 0.9.3
 *
 *	The author(s) of this software shall not be held liable for damages
 *	of any nature resulting due to the use of this software. This
 *	software is provided AS-IS with no warranties.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

#define NAME "it8712f_wdt"

MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
MODULE_DESCRIPTION("IT8712F Watchdog Driver");
MODULE_LICENSE("GPL");

static int max_units = 255;
static int margin = 60;		/* in seconds */
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds");

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");

static unsigned long wdt_open;
static unsigned expect_close;
static unsigned char revision;

/* Dog Food address - We use the game port address */
static unsigned short address;

#define	REG		0x2e	/* The register to read/write */
#define	VAL		0x2f	/* The value to read/write */

#define	LDN		0x07	/* Register: Logical device select */
#define	DEVID		0x20	/* Register: Device ID */
#define	DEVREV		0x22	/* Register: Device Revision */
#define ACT_REG		0x30	/* LDN Register: Activation */
#define BASE_REG	0x60	/* LDN Register: Base address */

#define IT8712F_DEVID	0x8712

#define LDN_GPIO	0x07	/* GPIO and Watch Dog Timer */
#define LDN_GAME	0x09	/* Game Port */

#define WDT_CONTROL	0x71	/* WDT Register: Control */
#define WDT_CONFIG	0x72	/* WDT Register: Configuration */
#define WDT_TIMEOUT	0x73	/* WDT Register: Timeout Value */

#define WDT_RESET_GAME	0x10	/* Reset timer on read or write to game port */
#define WDT_RESET_KBD	0x20	/* Reset timer on keyboard interrupt */
#define WDT_RESET_MOUSE	0x40	/* Reset timer on mouse interrupt */
#define WDT_RESET_CIR	0x80	/* Reset timer on consumer IR interrupt */

#define WDT_UNIT_SEC	0x80	/* If 0 in MINUTES */

#define WDT_OUT_PWROK	0x10	/* Pulse PWROK on timeout */
#define WDT_OUT_KRST	0x40	/* Pulse reset on timeout */

static int wdt_control_reg = WDT_RESET_GAME;
module_param(wdt_control_reg, int, 0);
MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
		"register. The default WDT_RESET_GAME resets the timer on "
		"game port reads that this driver generates. You can also "
		"use KBD, MOUSE or CIR if you have some external way to "
		"generate those interrupts.");

static int superio_inb(int reg)
{
	outb(reg, REG);
	return inb(VAL);
}

static void superio_outb(int val, int reg)
{
	outb(reg, REG);
	outb(val, VAL);
}

static int superio_inw(int reg)
{
	int val;
	outb(reg++, REG);
	val = inb(VAL) << 8;
	outb(reg, REG);
	val |= inb(VAL);
	return val;
}

static inline void superio_select(int ldn)
{
	outb(LDN, REG);
	outb(ldn, VAL);
}

static inline int superio_enter(void)
{
	/*
	 * Try to reserve REG and REG + 1 for exclusive access.
	 */
	if (!request_muxed_region(REG, 2, NAME))
		return -EBUSY;

	outb(0x87, REG);
	outb(0x01, REG);
	outb(0x55, REG);
	outb(0x55, REG);
	return 0;
}

static inline void superio_exit(void)
{
	outb(0x02, REG);
	outb(0x02, VAL);
	release_region(REG, 2);
}

static inline void it8712f_wdt_ping(void)
{
	if (wdt_control_reg & WDT_RESET_GAME)
		inb(address);
}

static void it8712f_wdt_update_margin(void)
{
	int config = WDT_OUT_KRST | WDT_OUT_PWROK;
	int units = margin;

	/* Switch to minutes precision if the configured margin
	 * value does not fit within the register width.
	 */
	if (units <= max_units) {
		config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
		pr_info("timer margin %d seconds\n", units);
	} else {
		units /= 60;
		pr_info("timer margin %d minutes\n", units);
	}
	superio_outb(config, WDT_CONFIG);

	if (revision >= 0x08)
		superio_outb(units >> 8, WDT_TIMEOUT + 1);
	superio_outb(units, WDT_TIMEOUT);
}

static int it8712f_wdt_get_status(void)
{
	if (superio_inb(WDT_CONTROL) & 0x01)
		return WDIOF_CARDRESET;
	else
		return 0;
}

static int it8712f_wdt_enable(void)
{
	int ret = superio_enter();
	if (ret)
		return ret;

	pr_debug("enabling watchdog timer\n");
	superio_select(LDN_GPIO);

	superio_outb(wdt_control_reg, WDT_CONTROL);

	it8712f_wdt_update_margin();

	superio_exit();

	it8712f_wdt_ping();

	return 0;
}

static int it8712f_wdt_disable(void)
{
	int ret = superio_enter();
	if (ret)
		return ret;

	pr_debug("disabling watchdog timer\n");
	superio_select(LDN_GPIO);

	superio_outb(0, WDT_CONFIG);
	superio_outb(0, WDT_CONTROL);
	if (revision >= 0x08)
		superio_outb(0, WDT_TIMEOUT + 1);
	superio_outb(0, WDT_TIMEOUT);

	superio_exit();
	return 0;
}

static int it8712f_wdt_notify(struct notifier_block *this,
		    unsigned long code, void *unused)
{
	if (code == SYS_HALT || code == SYS_POWER_OFF)
		if (!nowayout)
			it8712f_wdt_disable();

	return NOTIFY_DONE;
}

static struct notifier_block it8712f_wdt_notifier = {
	.notifier_call = it8712f_wdt_notify,
};

static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
					size_t len, loff_t *ppos)
{
	/* check for a magic close character */
	if (len) {
		size_t i;

		it8712f_wdt_ping();

		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;
		}
	}

	return len;
}

static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
		.identity = "IT8712F Watchdog",
		.firmware_version = 1,
		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
						WDIOF_MAGICCLOSE,
	};
	int value;
	int ret;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &ident, sizeof(ident)))
			return -EFAULT;
		return 0;
	case WDIOC_GETSTATUS:
		ret = superio_enter();
		if (ret)
			return ret;
		superio_select(LDN_GPIO);

		value = it8712f_wdt_get_status();

		superio_exit();

		return put_user(value, p);
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);
	case WDIOC_KEEPALIVE:
		it8712f_wdt_ping();
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(value, p))
			return -EFAULT;
		if (value < 1)
			return -EINVAL;
		if (value > (max_units * 60))
			return -EINVAL;
		margin = value;
		ret = superio_enter();
		if (ret)
			return ret;
		superio_select(LDN_GPIO);

		it8712f_wdt_update_margin();

		superio_exit();
		it8712f_wdt_ping();
		fallthrough;
	case WDIOC_GETTIMEOUT:
		if (put_user(margin, p))
			return -EFAULT;
		return 0;
	default:
		return -ENOTTY;
	}
}

static int it8712f_wdt_open(struct inode *inode, struct file *file)
{
	int ret;
	/* only allow one at a time */
	if (test_and_set_bit(0, &wdt_open))
		return -EBUSY;

	ret = it8712f_wdt_enable();
	if (ret)
		return ret;
	return stream_open(inode, file);
}

static int it8712f_wdt_release(struct inode *inode, struct file *file)
{
	if (expect_close != 42) {
		pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
	} else if (!nowayout) {
		if (it8712f_wdt_disable())
			pr_warn("Watchdog disable failed\n");
	}
	expect_close = 0;
	clear_bit(0, &wdt_open);

	return 0;
}

static const struct file_operations it8712f_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = it8712f_wdt_write,
	.unlocked_ioctl = it8712f_wdt_ioctl,
	.compat_ioctl = compat_ptr_ioctl,
	.open = it8712f_wdt_open,
	.release = it8712f_wdt_release,
};

static struct miscdevice it8712f_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &it8712f_wdt_fops,
};

static int __init it8712f_wdt_find(unsigned short *address)
{
	int err = -ENODEV;
	int chip_type;
	int ret = superio_enter();
	if (ret)
		return ret;

	chip_type = superio_inw(DEVID);
	if (chip_type != IT8712F_DEVID)
		goto exit;

	superio_select(LDN_GAME);
	superio_outb(1, ACT_REG);
	if (!(superio_inb(ACT_REG) & 0x01)) {
		pr_err("Device not activated, skipping\n");
		goto exit;
	}

	*address = superio_inw(BASE_REG);
	if (*address == 0) {
		pr_err("Base address not set, skipping\n");
		goto exit;
	}

	err = 0;
	revision = superio_inb(DEVREV) & 0x0f;

	/* Later revisions have 16-bit values per datasheet 0.9.1 */
	if (revision >= 0x08)
		max_units = 65535;

	if (margin > (max_units * 60))
		margin = (max_units * 60);

	pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
		chip_type, revision, *address);

exit:
	superio_exit();
	return err;
}

static int __init it8712f_wdt_init(void)
{
	int err = 0;

	if (it8712f_wdt_find(&address))
		return -ENODEV;

	if (!request_region(address, 1, "IT8712F Watchdog")) {
		pr_warn("watchdog I/O region busy\n");
		return -EBUSY;
	}

	err = it8712f_wdt_disable();
	if (err) {
		pr_err("unable to disable watchdog timer\n");
		goto out;
	}

	err = register_reboot_notifier(&it8712f_wdt_notifier);
	if (err) {
		pr_err("unable to register reboot notifier\n");
		goto out;
	}

	err = misc_register(&it8712f_wdt_miscdev);
	if (err) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       WATCHDOG_MINOR, err);
		goto reboot_out;
	}

	return 0;


reboot_out:
	unregister_reboot_notifier(&it8712f_wdt_notifier);
out:
	release_region(address, 1);
	return err;
}

static void __exit it8712f_wdt_exit(void)
{
	misc_deregister(&it8712f_wdt_miscdev);
	unregister_reboot_notifier(&it8712f_wdt_notifier);
	release_region(address, 1);
}

module_init(it8712f_wdt_init);
module_exit(it8712f_wdt_exit);
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
38ff6fd2 JBD	2	/*
	3	* IT8712F "Smart Guardian" Watchdog support
	4	*
	5	* Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
	6	*
	7	* Based on info and code taken from:
	8	*
	9	* drivers/char/watchdog/scx200_wdt.c
	10	* drivers/hwmon/it87.c
5e699608 AP	11	* IT8712F EC-LPC I/O Preliminary Specification 0.8.2
5e699608 AP	12	* IT8712F EC-LPC I/O Preliminary Specification 0.9.3
38ff6fd2	13	*
38ff6fd2 JBD	14	* The author(s) of this software shall not be held liable for damages
	15	* of any nature resulting due to the use of this software. This
	16	* software is provided AS-IS with no warranties.
	17	*/
	18
27c766aa JP	19	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	20
38ff6fd2 JBD	21	#include <linux/module.h>
	22	#include <linux/moduleparam.h>
	23	#include <linux/init.h>
	24	#include <linux/miscdevice.h>
	25	#include <linux/watchdog.h>
	26	#include <linux/notifier.h>
	27	#include <linux/reboot.h>
	28	#include <linux/fs.h>
38ff6fd2	29	#include <linux/spinlock.h>
d6547378 AC	30	#include <linux/uaccess.h>
d6547378 AC	31	#include <linux/io.h>
22602868	32	#include <linux/ioport.h>
38ff6fd2 JBD	33
	34	#define NAME "it8712f_wdt"
	35
	36	MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
	37	MODULE_DESCRIPTION("IT8712F Watchdog Driver");
	38	MODULE_LICENSE("GPL");
38ff6fd2	39
5e699608	40	static int max_units = 255;
38ff6fd2 JBD	41	static int margin = 60; /* in seconds */
	42	module_param(margin, int, 0);
	43	MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
	44
86a1e189 WVS	45	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	46	module_param(nowayout, bool, 0);
38ff6fd2 JBD	47	MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
38ff6fd2 JBD	48
d6547378	49	static unsigned long wdt_open;
38ff6fd2	50	static unsigned expect_close;
5e699608	51	static unsigned char revision;
38ff6fd2 JBD	52
	53	/* Dog Food address - We use the game port address */
	54	static unsigned short address;
	55
	56	#define REG 0x2e /* The register to read/write */
	57	#define VAL 0x2f /* The value to read/write */
	58
	59	#define LDN 0x07 /* Register: Logical device select */
	60	#define DEVID 0x20 /* Register: Device ID */
	61	#define DEVREV 0x22 /* Register: Device Revision */
	62	#define ACT_REG 0x30 /* LDN Register: Activation */
	63	#define BASE_REG 0x60 /* LDN Register: Base address */
	64
	65	#define IT8712F_DEVID 0x8712
	66
	67	#define LDN_GPIO 0x07 /* GPIO and Watch Dog Timer */
5f3b2756	68	#define LDN_GAME 0x09 /* Game Port */
38ff6fd2 JBD	69
	70	#define WDT_CONTROL 0x71 /* WDT Register: Control */
	71	#define WDT_CONFIG 0x72 /* WDT Register: Configuration */
	72	#define WDT_TIMEOUT 0x73 /* WDT Register: Timeout Value */
	73
f0fc1074 TJL	74	#define WDT_RESET_GAME 0x10 /* Reset timer on read or write to game port */
	75	#define WDT_RESET_KBD 0x20 /* Reset timer on keyboard interrupt */
	76	#define WDT_RESET_MOUSE 0x40 /* Reset timer on mouse interrupt */
	77	#define WDT_RESET_CIR 0x80 /* Reset timer on consumer IR interrupt */
38ff6fd2 JBD	78
	79	#define WDT_UNIT_SEC 0x80 /* If 0 in MINUTES */
	80
f0fc1074 TJL	81	#define WDT_OUT_PWROK 0x10 /* Pulse PWROK on timeout */
f0fc1074 TJL	82	#define WDT_OUT_KRST 0x40 /* Pulse reset on timeout */
38ff6fd2	83
a422088d TJL	84	static int wdt_control_reg = WDT_RESET_GAME;
	85	module_param(wdt_control_reg, int, 0);
	86	MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
	87	"register. The default WDT_RESET_GAME resets the timer on "
	88	"game port reads that this driver generates. You can also "
	89	"use KBD, MOUSE or CIR if you have some external way to "
	90	"generate those interrupts.");
	91
d6547378	92	static int superio_inb(int reg)
38ff6fd2 JBD	93	{
	94	outb(reg, REG);
	95	return inb(VAL);
	96	}
	97
d6547378	98	static void superio_outb(int val, int reg)
38ff6fd2 JBD	99	{
	100	outb(reg, REG);
	101	outb(val, VAL);
	102	}
	103
d6547378	104	static int superio_inw(int reg)
38ff6fd2 JBD	105	{
	106	int val;
	107	outb(reg++, REG);
	108	val = inb(VAL) << 8;
	109	outb(reg, REG);
	110	val \|= inb(VAL);
	111	return val;
	112	}
	113
d6547378	114	static inline void superio_select(int ldn)
38ff6fd2 JBD	115	{
	116	outb(LDN, REG);
	117	outb(ldn, VAL);
	118	}
	119
a134b825	120	static inline int superio_enter(void)
38ff6fd2	121	{
a134b825 NG	122	/*
	123	* Try to reserve REG and REG + 1 for exclusive access.
	124	*/
	125	if (!request_muxed_region(REG, 2, NAME))
	126	return -EBUSY;
	127
38ff6fd2 JBD	128	outb(0x87, REG);
	129	outb(0x01, REG);
	130	outb(0x55, REG);
	131	outb(0x55, REG);
a134b825	132	return 0;
38ff6fd2 JBD	133	}
38ff6fd2 JBD	134
d6547378	135	static inline void superio_exit(void)
38ff6fd2 JBD	136	{
	137	outb(0x02, REG);
	138	outb(0x02, VAL);
a134b825	139	release_region(REG, 2);
38ff6fd2 JBD	140	}
38ff6fd2 JBD	141
d6547378	142	static inline void it8712f_wdt_ping(void)
38ff6fd2	143	{
a422088d TJL	144	if (wdt_control_reg & WDT_RESET_GAME)
a422088d TJL	145	inb(address);
38ff6fd2 JBD	146	}
38ff6fd2 JBD	147
d6547378	148	static void it8712f_wdt_update_margin(void)
38ff6fd2 JBD	149	{
38ff6fd2 JBD	150	int config = WDT_OUT_KRST \| WDT_OUT_PWROK;
5e699608 AP	151	int units = margin;
	152
	153	/* Switch to minutes precision if the configured margin
	154	* value does not fit within the register width.
	155	*/
	156	if (units <= max_units) {
	157	config \|= WDT_UNIT_SEC; /* else UNIT is MINUTES */
27c766aa	158	pr_info("timer margin %d seconds\n", units);
5e699608 AP	159	} else {
5e699608 AP	160	units /= 60;
27c766aa	161	pr_info("timer margin %d minutes\n", units);
5e699608	162	}
38ff6fd2 JBD	163	superio_outb(config, WDT_CONFIG);
38ff6fd2 JBD	164
5e699608	165	if (revision >= 0x08)
0e45adb8 OS	166	superio_outb(units >> 8, WDT_TIMEOUT + 1);
0e45adb8 OS	167	superio_outb(units, WDT_TIMEOUT);
5e699608 AP	168	}
5e699608 AP	169
d6547378	170	static int it8712f_wdt_get_status(void)
5e699608 AP	171	{
	172	if (superio_inb(WDT_CONTROL) & 0x01)
	173	return WDIOF_CARDRESET;
	174	else
	175	return 0;
38ff6fd2 JBD	176	}
38ff6fd2 JBD	177
a134b825	178	static int it8712f_wdt_enable(void)
38ff6fd2	179	{
a134b825 NG	180	int ret = superio_enter();
	181	if (ret)
	182	return ret;
	183
27c766aa	184	pr_debug("enabling watchdog timer\n");
38ff6fd2 JBD	185	superio_select(LDN_GPIO);
38ff6fd2 JBD	186
a422088d	187	superio_outb(wdt_control_reg, WDT_CONTROL);
38ff6fd2 JBD	188
	189	it8712f_wdt_update_margin();
	190
	191	superio_exit();
	192
	193	it8712f_wdt_ping();
a134b825 NG	194
a134b825 NG	195	return 0;
38ff6fd2 JBD	196	}
38ff6fd2 JBD	197
a134b825	198	static int it8712f_wdt_disable(void)
38ff6fd2	199	{
a134b825 NG	200	int ret = superio_enter();
	201	if (ret)
	202	return ret;
38ff6fd2	203
27c766aa	204	pr_debug("disabling watchdog timer\n");
38ff6fd2 JBD	205	superio_select(LDN_GPIO);
	206
	207	superio_outb(0, WDT_CONFIG);
	208	superio_outb(0, WDT_CONTROL);
cc1020f1 AP	209	if (revision >= 0x08)
cc1020f1 AP	210	superio_outb(0, WDT_TIMEOUT + 1);
38ff6fd2 JBD	211	superio_outb(0, WDT_TIMEOUT);
	212
	213	superio_exit();
a134b825	214	return 0;
38ff6fd2 JBD	215	}
38ff6fd2 JBD	216
d6547378	217	static int it8712f_wdt_notify(struct notifier_block *this,
38ff6fd2 JBD	218	unsigned long code, void *unused)
	219	{
	220	if (code == SYS_HALT \|\| code == SYS_POWER_OFF)
	221	if (!nowayout)
	222	it8712f_wdt_disable();
	223
	224	return NOTIFY_DONE;
	225	}
	226
	227	static struct notifier_block it8712f_wdt_notifier = {
	228	.notifier_call = it8712f_wdt_notify,
	229	};
	230
d6547378 AC	231	static ssize_t it8712f_wdt_write(struct file file, const char __user data,
d6547378 AC	232	size_t len, loff_t *ppos)
38ff6fd2 JBD	233	{
	234	/* check for a magic close character */
	235	if (len) {
	236	size_t i;
	237
	238	it8712f_wdt_ping();
	239
	240	expect_close = 0;
	241	for (i = 0; i < len; ++i) {
	242	char c;
7944d3a5	243	if (get_user(c, data + i))
38ff6fd2 JBD	244	return -EFAULT;
	245	if (c == 'V')
	246	expect_close = 42;
	247	}
	248	}
	249
	250	return len;
	251	}
	252
d6547378 AC	253	static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
d6547378 AC	254	unsigned long arg)
38ff6fd2 JBD	255	{
	256	void __user argp = (void __user )arg;
	257	int __user *p = argp;
42747d71	258	static const struct watchdog_info ident = {
38ff6fd2 JBD	259	.identity = "IT8712F Watchdog",
38ff6fd2 JBD	260	.firmware_version = 1,
e73a7802 WVS	261	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
e73a7802 WVS	262	WDIOF_MAGICCLOSE,
38ff6fd2	263	};
5e699608	264	int value;
a134b825	265	int ret;
38ff6fd2 JBD	266
38ff6fd2 JBD	267	switch (cmd) {
38ff6fd2 JBD	268	case WDIOC_GETSUPPORT:
	269	if (copy_to_user(argp, &ident, sizeof(ident)))
	270	return -EFAULT;
	271	return 0;
	272	case WDIOC_GETSTATUS:
a134b825 NG	273	ret = superio_enter();
	274	if (ret)
	275	return ret;
5e699608 AP	276	superio_select(LDN_GPIO);
	277
	278	value = it8712f_wdt_get_status();
	279
	280	superio_exit();
	281
	282	return put_user(value, p);
38ff6fd2 JBD	283	case WDIOC_GETBOOTSTATUS:
	284	return put_user(0, p);
	285	case WDIOC_KEEPALIVE:
	286	it8712f_wdt_ping();
	287	return 0;
	288	case WDIOC_SETTIMEOUT:
5e699608	289	if (get_user(value, p))
38ff6fd2	290	return -EFAULT;
5e699608 AP	291	if (value < 1)
	292	return -EINVAL;
	293	if (value > (max_units * 60))
38ff6fd2	294	return -EINVAL;
5e699608	295	margin = value;
a134b825 NG	296	ret = superio_enter();
	297	if (ret)
	298	return ret;
38ff6fd2 JBD	299	superio_select(LDN_GPIO);
	300
	301	it8712f_wdt_update_margin();
	302
	303	superio_exit();
	304	it8712f_wdt_ping();
bd490f82	305	fallthrough;
38ff6fd2 JBD	306	case WDIOC_GETTIMEOUT:
	307	if (put_user(margin, p))
	308	return -EFAULT;
	309	return 0;
0c06090c WVS	310	default:
0c06090c WVS	311	return -ENOTTY;
38ff6fd2 JBD	312	}
	313	}
	314
d6547378	315	static int it8712f_wdt_open(struct inode inode, struct file file)
38ff6fd2	316	{
a134b825	317	int ret;
38ff6fd2	318	/* only allow one at a time */
d6547378	319	if (test_and_set_bit(0, &wdt_open))
38ff6fd2	320	return -EBUSY;
a134b825 NG	321
	322	ret = it8712f_wdt_enable();
	323	if (ret)
	324	return ret;
c5bf68fe	325	return stream_open(inode, file);
38ff6fd2 JBD	326	}
38ff6fd2 JBD	327
d6547378	328	static int it8712f_wdt_release(struct inode inode, struct file file)
38ff6fd2 JBD	329	{
38ff6fd2 JBD	330	if (expect_close != 42) {
27c766aa	331	pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
38ff6fd2	332	} else if (!nowayout) {
a134b825	333	if (it8712f_wdt_disable())
27c766aa	334	pr_warn("Watchdog disable failed\n");
38ff6fd2 JBD	335	}
38ff6fd2 JBD	336	expect_close = 0;
d6547378	337	clear_bit(0, &wdt_open);
38ff6fd2 JBD	338
	339	return 0;
	340	}
	341
b47a166e	342	static const struct file_operations it8712f_wdt_fops = {
38ff6fd2 JBD	343	.owner = THIS_MODULE,
	344	.llseek = no_llseek,
	345	.write = it8712f_wdt_write,
d6547378	346	.unlocked_ioctl = it8712f_wdt_ioctl,
b6dfb247	347	.compat_ioctl = compat_ptr_ioctl,
38ff6fd2 JBD	348	.open = it8712f_wdt_open,
	349	.release = it8712f_wdt_release,
	350	};
	351
	352	static struct miscdevice it8712f_wdt_miscdev = {
	353	.minor = WATCHDOG_MINOR,
	354	.name = "watchdog",
	355	.fops = &it8712f_wdt_fops,
	356	};
	357
d6547378	358	static int __init it8712f_wdt_find(unsigned short *address)
38ff6fd2 JBD	359	{
	360	int err = -ENODEV;
	361	int chip_type;
a134b825 NG	362	int ret = superio_enter();
	363	if (ret)
	364	return ret;
38ff6fd2	365
38ff6fd2 JBD	366	chip_type = superio_inw(DEVID);
	367	if (chip_type != IT8712F_DEVID)
	368	goto exit;
	369
	370	superio_select(LDN_GAME);
	371	superio_outb(1, ACT_REG);
	372	if (!(superio_inb(ACT_REG) & 0x01)) {
27c766aa	373	pr_err("Device not activated, skipping\n");
38ff6fd2 JBD	374	goto exit;
	375	}
	376
	377	*address = superio_inw(BASE_REG);
	378	if (*address == 0) {
27c766aa	379	pr_err("Base address not set, skipping\n");
38ff6fd2 JBD	380	goto exit;
	381	}
	382
	383	err = 0;
5e699608 AP	384	revision = superio_inb(DEVREV) & 0x0f;
	385
	386	/* Later revisions have 16-bit values per datasheet 0.9.1 */
	387	if (revision >= 0x08)
	388	max_units = 65535;
	389
	390	if (margin > (max_units * 60))
	391	margin = (max_units * 60);
	392
27c766aa	393	pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
5e699608	394	chip_type, revision, *address);
38ff6fd2 JBD	395
	396	exit:
	397	superio_exit();
	398	return err;
	399	}
	400
d6547378	401	static int __init it8712f_wdt_init(void)
38ff6fd2 JBD	402	{
	403	int err = 0;
	404
38ff6fd2 JBD	405	if (it8712f_wdt_find(&address))
	406	return -ENODEV;
	407
	408	if (!request_region(address, 1, "IT8712F Watchdog")) {
27c766aa	409	pr_warn("watchdog I/O region busy\n");
38ff6fd2 JBD	410	return -EBUSY;
	411	}
	412
a134b825 NG	413	err = it8712f_wdt_disable();
a134b825 NG	414	if (err) {
27c766aa	415	pr_err("unable to disable watchdog timer\n");
a134b825 NG	416	goto out;
a134b825 NG	417	}
38ff6fd2	418
38ff6fd2 JBD	419	err = register_reboot_notifier(&it8712f_wdt_notifier);
38ff6fd2 JBD	420	if (err) {
27c766aa	421	pr_err("unable to register reboot notifier\n");
38ff6fd2 JBD	422	goto out;
	423	}
	424
	425	err = misc_register(&it8712f_wdt_miscdev);
	426	if (err) {
27c766aa JP	427	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
27c766aa JP	428	WATCHDOG_MINOR, err);
38ff6fd2 JBD	429	goto reboot_out;
	430	}
	431
	432	return 0;
	433
	434
	435	reboot_out:
	436	unregister_reboot_notifier(&it8712f_wdt_notifier);
	437	out:
	438	release_region(address, 1);
	439	return err;
	440	}
	441
d6547378	442	static void __exit it8712f_wdt_exit(void)
38ff6fd2 JBD	443	{
	444	misc_deregister(&it8712f_wdt_miscdev);
	445	unregister_reboot_notifier(&it8712f_wdt_notifier);
	446	release_region(address, 1);
	447	}
	448
	449	module_init(it8712f_wdt_init);
	450	module_exit(it8712f_wdt_exit);