drivers/watchdog/it87_wdt.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	Watchdog Timer Driver
  *	   for ITE IT87xx Environment Control - Low Pin Count Input / Output
  *
  *	(c) Copyright 2007  Oliver Schuster <olivers137@aol.com>
  *
  *	Based on softdog.c	by Alan Cox,
  *		 83977f_wdt.c	by Jose Goncalves,
  *		 it87.c		by Chris Gauthron, Jean Delvare
  *
  *	Data-sheets: Publicly available at the ITE website
  *		    http://www.ite.com.tw/
  *
  *	Support of the watchdog timers, which are available on
  *	IT8607, IT8620, IT8622, IT8625, IT8628, IT8655, IT8665, IT8686,
  *	IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726, IT8728,
  *	and IT8783.
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/watchdog.h>

 #define WATCHDOG_NAME		"IT87 WDT"

 /* Defaults for Module Parameter */
 #define DEFAULT_TIMEOUT		60
 #define DEFAULT_TESTMODE	0
 #define DEFAULT_NOWAYOUT	WATCHDOG_NOWAYOUT

 /* IO Ports */
 #define REG		0x2e
 #define VAL		0x2f

 /* Logical device Numbers LDN */
 #define GPIO		0x07

 /* Configuration Registers and Functions */
 #define LDNREG		0x07
 #define CHIPID		0x20
 #define CHIPREV		0x22

 /* Chip Id numbers */
 #define NO_DEV_ID	0xffff
 #define IT8607_ID	0x8607
 #define IT8620_ID	0x8620
 #define IT8622_ID	0x8622
 #define IT8625_ID	0x8625
 #define IT8628_ID	0x8628
 #define IT8655_ID	0x8655
 #define IT8665_ID	0x8665
 #define IT8686_ID	0x8686
 #define IT8702_ID	0x8702
 #define IT8705_ID	0x8705
 #define IT8712_ID	0x8712
 #define IT8716_ID	0x8716
 #define IT8718_ID	0x8718
 #define IT8720_ID	0x8720
 #define IT8721_ID	0x8721
 #define IT8726_ID	0x8726	/* the data sheet suggest wrongly 0x8716 */
 #define IT8728_ID	0x8728
 #define IT8783_ID	0x8783

 /* GPIO Configuration Registers LDN=0x07 */
 #define WDTCTRL		0x71
 #define WDTCFG		0x72
 #define WDTVALLSB	0x73
 #define WDTVALMSB	0x74

 /* GPIO Bits WDTCFG */
 #define WDT_TOV1	0x80
 #define WDT_KRST	0x40
 #define WDT_TOVE	0x20
 #define WDT_PWROK	0x10 /* not in it8721 */
 #define WDT_INT_MASK	0x0f

 static unsigned int max_units, chip_type;

 static unsigned int timeout = DEFAULT_TIMEOUT;
 static int testmode = DEFAULT_TESTMODE;
 static bool nowayout = DEFAULT_NOWAYOUT;

 module_param(timeout, int, 0);
 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
 		__MODULE_STRING(DEFAULT_TIMEOUT));
 module_param(testmode, int, 0);
 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
 		__MODULE_STRING(DEFAULT_TESTMODE));
 module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
 		__MODULE_STRING(WATCHDOG_NOWAYOUT));

 /* Superio Chip */

 static inline int superio_enter(void)
 {
 	/*
 	 * Try to reserve REG and REG + 1 for exclusive access.
 	 */
 	if (!request_muxed_region(REG, 2, WATCHDOG_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 superio_select(int ldn)
 {
 	outb(LDNREG, REG);
 	outb(ldn, VAL);
 }

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

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

 static inline 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_outw(int val, int reg)
 {
 	outb(reg++, REG);
 	outb(val >> 8, VAL);
 	outb(reg, REG);
 	outb(val, VAL);
 }

 /* Internal function, should be called after superio_select(GPIO) */
 static void _wdt_update_timeout(unsigned int t)
 {
 	unsigned char cfg = WDT_KRST;

 	if (testmode)
 		cfg = 0;

 	if (t <= max_units)
 		cfg |= WDT_TOV1;
 	else
 		t /= 60;

 	if (chip_type != IT8721_ID)
 		cfg |= WDT_PWROK;

 	superio_outb(cfg, WDTCFG);
 	superio_outb(t, WDTVALLSB);
 	if (max_units > 255)
 		superio_outb(t >> 8, WDTVALMSB);
 }

 static int wdt_update_timeout(unsigned int t)
 {
 	int ret;

 	ret = superio_enter();
 	if (ret)
 		return ret;

 	superio_select(GPIO);
 	_wdt_update_timeout(t);
 	superio_exit();

 	return 0;
 }

 static int wdt_round_time(int t)
 {
 	t += 59;
 	t -= t % 60;
 	return t;
 }

 /* watchdog timer handling */

 static int wdt_start(struct watchdog_device *wdd)
 {
 	return wdt_update_timeout(wdd->timeout);
 }

 static int wdt_stop(struct watchdog_device *wdd)
 {
 	return wdt_update_timeout(0);
 }

 /**
  *	wdt_set_timeout - set a new timeout value with watchdog ioctl
  *	@t: timeout value in seconds
  *
  *	The hardware device has a 8 or 16 bit watchdog timer (depends on
  *	chip version) that can be configured to count seconds or minutes.
  *
  *	Used within WDIOC_SETTIMEOUT watchdog device ioctl.
  */

 static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
 {
 	int ret = 0;

 	if (t > max_units)
 		t = wdt_round_time(t);

 	wdd->timeout = t;

 	if (watchdog_hw_running(wdd))
 		ret = wdt_update_timeout(t);

 	return ret;
 }

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

 static const struct watchdog_ops wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = wdt_start,
 	.stop = wdt_stop,
 	.set_timeout = wdt_set_timeout,
 };

 static struct watchdog_device wdt_dev = {
 	.info = &ident,
 	.ops = &wdt_ops,
 	.min_timeout = 1,
 };

 static int __init it87_wdt_init(void)
 {
 	u8  chip_rev;
 	int rc;

 	rc = superio_enter();
 	if (rc)
 		return rc;

 	chip_type = superio_inw(CHIPID);
 	chip_rev  = superio_inb(CHIPREV) & 0x0f;
 	superio_exit();

 	switch (chip_type) {
 	case IT8702_ID:
 		max_units = 255;
 		break;
 	case IT8712_ID:
 		max_units = (chip_rev < 8) ? 255 : 65535;
 		break;
 	case IT8716_ID:
 	case IT8726_ID:
 		max_units = 65535;
 		break;
 	case IT8607_ID:
 	case IT8620_ID:
 	case IT8622_ID:
 	case IT8625_ID:
 	case IT8628_ID:
 	case IT8655_ID:
 	case IT8665_ID:
 	case IT8686_ID:
 	case IT8718_ID:
 	case IT8720_ID:
 	case IT8721_ID:
 	case IT8728_ID:
 	case IT8783_ID:
 		max_units = 65535;
 		break;
 	case IT8705_ID:
 		pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
 		       chip_type, chip_rev);
 		return -ENODEV;
 	case NO_DEV_ID:
 		pr_err("no device\n");
 		return -ENODEV;
 	default:
 		pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
 		       chip_type, chip_rev);
 		return -ENODEV;
 	}

 	rc = superio_enter();
 	if (rc)
 		return rc;

 	superio_select(GPIO);
 	superio_outb(WDT_TOV1, WDTCFG);
 	superio_outb(0x00, WDTCTRL);
 	superio_exit();

 	if (timeout < 1 || timeout > max_units * 60) {
 		timeout = DEFAULT_TIMEOUT;
 		pr_warn("Timeout value out of range, use default %d sec\n",
 			DEFAULT_TIMEOUT);
 	}

 	if (timeout > max_units)
 		timeout = wdt_round_time(timeout);

 	wdt_dev.timeout = timeout;
 	wdt_dev.max_timeout = max_units * 60;

 	watchdog_stop_on_reboot(&wdt_dev);
 	rc = watchdog_register_device(&wdt_dev);
 	if (rc) {
 		pr_err("Cannot register watchdog device (err=%d)\n", rc);
 		return rc;
 	}

 	pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
 		chip_type, chip_rev, timeout, nowayout, testmode);

 	return 0;
 }

 static void __exit it87_wdt_exit(void)
 {
 	watchdog_unregister_device(&wdt_dev);
 }

 module_init(it87_wdt_init);
 module_exit(it87_wdt_exit);

 MODULE_AUTHOR("Oliver Schuster");
 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Watchdog Timer Driver
	* for ITE IT87xx Environment Control - Low Pin Count Input / Output
	*
	* (c) Copyright 2007 Oliver Schuster <olivers137@aol.com>
	*
	* Based on softdog.c by Alan Cox,
	* 83977f_wdt.c by Jose Goncalves,
	* it87.c by Chris Gauthron, Jean Delvare
	*
	* Data-sheets: Publicly available at the ITE website
	* http://www.ite.com.tw/
	*
	* Support of the watchdog timers, which are available on
	* IT8607, IT8620, IT8622, IT8625, IT8628, IT8655, IT8665, IT8686,
	* IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726, IT8728,
	* and IT8783.
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/init.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/types.h>
	#include <linux/watchdog.h>

	#define WATCHDOG_NAME "IT87 WDT"

	/* Defaults for Module Parameter */
	#define DEFAULT_TIMEOUT 60
	#define DEFAULT_TESTMODE 0
	#define DEFAULT_NOWAYOUT WATCHDOG_NOWAYOUT

	/* IO Ports */
	#define REG 0x2e
	#define VAL 0x2f

	/* Logical device Numbers LDN */
	#define GPIO 0x07

	/* Configuration Registers and Functions */
	#define LDNREG 0x07
	#define CHIPID 0x20
	#define CHIPREV 0x22

	/* Chip Id numbers */
	#define NO_DEV_ID 0xffff
	#define IT8607_ID 0x8607
	#define IT8620_ID 0x8620
	#define IT8622_ID 0x8622
	#define IT8625_ID 0x8625
	#define IT8628_ID 0x8628
	#define IT8655_ID 0x8655
	#define IT8665_ID 0x8665
	#define IT8686_ID 0x8686
	#define IT8702_ID 0x8702
	#define IT8705_ID 0x8705
	#define IT8712_ID 0x8712
	#define IT8716_ID 0x8716
	#define IT8718_ID 0x8718
	#define IT8720_ID 0x8720
	#define IT8721_ID 0x8721
	#define IT8726_ID 0x8726 /* the data sheet suggest wrongly 0x8716 */
	#define IT8728_ID 0x8728
	#define IT8783_ID 0x8783

	/* GPIO Configuration Registers LDN=0x07 */
	#define WDTCTRL 0x71
	#define WDTCFG 0x72
	#define WDTVALLSB 0x73
	#define WDTVALMSB 0x74

	/* GPIO Bits WDTCFG */
	#define WDT_TOV1 0x80
	#define WDT_KRST 0x40
	#define WDT_TOVE 0x20
	#define WDT_PWROK 0x10 /* not in it8721 */
	#define WDT_INT_MASK 0x0f

	static unsigned int max_units, chip_type;

	static unsigned int timeout = DEFAULT_TIMEOUT;
	static int testmode = DEFAULT_TESTMODE;
	static bool nowayout = DEFAULT_NOWAYOUT;

	module_param(timeout, int, 0);
	MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
	__MODULE_STRING(DEFAULT_TIMEOUT));
	module_param(testmode, int, 0);
	MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
	__MODULE_STRING(DEFAULT_TESTMODE));
	module_param(nowayout, bool, 0);
	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT));

	/* Superio Chip */

	static inline int superio_enter(void)
	{
	/*
	* Try to reserve REG and REG + 1 for exclusive access.
	*/
	if (!request_muxed_region(REG, 2, WATCHDOG_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 superio_select(int ldn)
	{
	outb(LDNREG, REG);
	outb(ldn, VAL);
	}

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

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

	static inline 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_outw(int val, int reg)
	{
	outb(reg++, REG);
	outb(val >> 8, VAL);
	outb(reg, REG);
	outb(val, VAL);
	}

	/* Internal function, should be called after superio_select(GPIO) */
	static void _wdt_update_timeout(unsigned int t)
	{
	unsigned char cfg = WDT_KRST;

	if (testmode)
	cfg = 0;

	if (t <= max_units)
	cfg \|= WDT_TOV1;
	else
	t /= 60;

	if (chip_type != IT8721_ID)
	cfg \|= WDT_PWROK;

	superio_outb(cfg, WDTCFG);
	superio_outb(t, WDTVALLSB);
	if (max_units > 255)
	superio_outb(t >> 8, WDTVALMSB);
	}

	static int wdt_update_timeout(unsigned int t)
	{
	int ret;

	ret = superio_enter();
	if (ret)
	return ret;

	superio_select(GPIO);
	_wdt_update_timeout(t);
	superio_exit();

	return 0;
	}

	static int wdt_round_time(int t)
	{
	t += 59;
	t -= t % 60;
	return t;
	}

	/* watchdog timer handling */

	static int wdt_start(struct watchdog_device *wdd)
	{
	return wdt_update_timeout(wdd->timeout);
	}

	static int wdt_stop(struct watchdog_device *wdd)
	{
	return wdt_update_timeout(0);
	}

	/**
	* wdt_set_timeout - set a new timeout value with watchdog ioctl
	* @t: timeout value in seconds
	*
	* The hardware device has a 8 or 16 bit watchdog timer (depends on
	* chip version) that can be configured to count seconds or minutes.
	*
	* Used within WDIOC_SETTIMEOUT watchdog device ioctl.
	*/

	static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
	{
	int ret = 0;

	if (t > max_units)
	t = wdt_round_time(t);

	wdd->timeout = t;

	if (watchdog_hw_running(wdd))
	ret = wdt_update_timeout(t);

	return ret;
	}

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

	static const struct watchdog_ops wdt_ops = {
	.owner = THIS_MODULE,
	.start = wdt_start,
	.stop = wdt_stop,
	.set_timeout = wdt_set_timeout,
	};

	static struct watchdog_device wdt_dev = {
	.info = &ident,
	.ops = &wdt_ops,
	.min_timeout = 1,
	};

	static int __init it87_wdt_init(void)
	{
	u8 chip_rev;
	int rc;

	rc = superio_enter();
	if (rc)
	return rc;

	chip_type = superio_inw(CHIPID);
	chip_rev = superio_inb(CHIPREV) & 0x0f;
	superio_exit();

	switch (chip_type) {
	case IT8702_ID:
	max_units = 255;
	break;
	case IT8712_ID:
	max_units = (chip_rev < 8) ? 255 : 65535;
	break;
	case IT8716_ID:
	case IT8726_ID:
	max_units = 65535;
	break;
	case IT8607_ID:
	case IT8620_ID:
	case IT8622_ID:
	case IT8625_ID:
	case IT8628_ID:
	case IT8655_ID:
	case IT8665_ID:
	case IT8686_ID:
	case IT8718_ID:
	case IT8720_ID:
	case IT8721_ID:
	case IT8728_ID:
	case IT8783_ID:
	max_units = 65535;
	break;
	case IT8705_ID:
	pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
	chip_type, chip_rev);
	return -ENODEV;
	case NO_DEV_ID:
	pr_err("no device\n");
	return -ENODEV;
	default:
	pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
	chip_type, chip_rev);
	return -ENODEV;
	}

	rc = superio_enter();
	if (rc)
	return rc;

	superio_select(GPIO);
	superio_outb(WDT_TOV1, WDTCFG);
	superio_outb(0x00, WDTCTRL);
	superio_exit();

	if (timeout < 1 \|\| timeout > max_units * 60) {
	timeout = DEFAULT_TIMEOUT;
	pr_warn("Timeout value out of range, use default %d sec\n",
	DEFAULT_TIMEOUT);
	}

	if (timeout > max_units)
	timeout = wdt_round_time(timeout);

	wdt_dev.timeout = timeout;
	wdt_dev.max_timeout = max_units * 60;

	watchdog_stop_on_reboot(&wdt_dev);
	rc = watchdog_register_device(&wdt_dev);
	if (rc) {
	pr_err("Cannot register watchdog device (err=%d)\n", rc);
	return rc;
	}

	pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
	chip_type, chip_rev, timeout, nowayout, testmode);

	return 0;
	}

	static void __exit it87_wdt_exit(void)
	{
	watchdog_unregister_device(&wdt_dev);
	}

	module_init(it87_wdt_init);
	module_exit(it87_wdt_exit);

	MODULE_AUTHOR("Oliver Schuster");
	MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
	MODULE_LICENSE("GPL");