[WATCHDOG] IT8212F watchdog driver

This patch adds support for the ITE Tech Inc. IT8712F EC-LPC Super I/O
chipset found on many Pentium III and AMD motherboards. Developed using code
from other watchdog drivers and the datasheet on ITE Tech homepage.

Signed-off-by: Jorge Boncompte <[e-mail]>
Signed-off-by: Wim Van Sebroeck <[e-mail]>

drivers/watchdog/Kconfig

···
 	  devices. At this moment we only have additional support for some
 	  SuperMicro Inc. motherboards.
 
+config IT8712F_WDT
+	tristate "IT8712F (Smart Guardian) Watchdog Timer"
+	depends on X86
+	---help---
+	  This is the driver for the built-in watchdog timer on the IT8712F
+	  Super I/0 chipset used on many motherboards.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called it8712f_wdt.
+
 config SC1200_WDT
 	tristate "National Semiconductor PC87307/PC97307 (ala SC1200) Watchdog"
 	depends on X86

drivers/watchdog/Makefile

···
 obj-$(CONFIG_WAFER_WDT) += wafer5823wdt.o
 obj-$(CONFIG_I6300ESB_WDT) += i6300esb.o
 obj-$(CONFIG_ITCO_WDT) += iTCO_wdt.o iTCO_vendor_support.o
+obj-$(CONFIG_IT8712F_WDT) += it8712f_wdt.o
 obj-$(CONFIG_SC1200_WDT) += sc1200wdt.o
 obj-$(CONFIG_SCx200_WDT) += scx200_wdt.o
 obj-$(CONFIG_PC87413_WDT) += pc87413_wdt.o

drivers/watchdog/it8712f_wdt.c

···
+/*
+ *	IT8712F "Smart Guardian" Watchdog support
+ *
+ *	Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <[e-mail]>
+ *
+ *	Based on info and code taken from:
+ *
+ *	drivers/char/watchdog/scx200_wdt.c
+ *	drivers/hwmon/it87.c
+ *	IT8712F EC-LPC I/O Preliminary Specification 0.9.2.pdf
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License as
+ *	published by the Free Software Foundation; either version 2 of the
+ *	License, or (at your option) any later version.
+ *
+ *	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.
+ */
+
+#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/pci.h>
+#include <linux/spinlock.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#define NAME "it8712f_wdt"
+
+MODULE_AUTHOR("Jorge Boncompte - DTI2 <[e-mail]>");
+MODULE_DESCRIPTION("IT8712F Watchdog Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+
+static int margin = 60;		/* in seconds */
+module_param(margin, int, 0);
+MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
+
+static struct semaphore it8712f_wdt_sem;
+static unsigned expect_close;
+static spinlock_t io_lock;
+
+/* 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
+#define WDT_RESET_KBD	0x20
+#define WDT_RESET_MOUSE	0x40
+#define WDT_RESET_CIR	0x80
+
+#define WDT_UNIT_SEC	0x80	/* If 0 in MINUTES */
+
+#define WDT_OUT_PWROK	0x10
+#define WDT_OUT_KRST	0x40
+
+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 void
+superio_enter(void)
+{
+	spin_lock(&io_lock);
+	outb(0x87, REG);
+	outb(0x01, REG);
+	outb(0x55, REG);
+	outb(0x55, REG);
+}
+
+static inline void
+superio_exit(void)
+{
+	outb(0x02, REG);
+	outb(0x02, VAL);
+	spin_unlock(&io_lock);
+}
+
+static inline void
+it8712f_wdt_ping(void)
+{
+	inb(address);
+}
+
+static void
+it8712f_wdt_update_margin(void)
+{
+	int config = WDT_OUT_KRST | WDT_OUT_PWROK;
+
+	printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
+
+	/* The timeout register only has 8bits wide */
+	if (margin < 256)
+		config |= WDT_UNIT_SEC;	/* else UNIT are MINUTES */
+	superio_outb(config, WDT_CONFIG);
+
+	superio_outb((margin > 255) ? (margin / 60) : margin, WDT_TIMEOUT);
+}
+
+static void
+it8712f_wdt_enable(void)
+{
+	printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
+	superio_enter();
+	superio_select(LDN_GPIO);
+
+	superio_outb(WDT_RESET_GAME, WDT_CONTROL);
+
+	it8712f_wdt_update_margin();
+
+	superio_exit();
+
+	it8712f_wdt_ping();
+}
+
+static void
+it8712f_wdt_disable(void)
+{
+	printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
+
+	superio_enter();
+	superio_select(LDN_GPIO);
+
+	superio_outb(0, WDT_CONFIG);
+	superio_outb(0, WDT_CONTROL);
+	superio_outb(0, WDT_TIMEOUT);
+
+	superio_exit();
+}
+
+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 int
+it8712f_wdt_ioctl(struct inode *inode, struct file *file,
+	unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	static struct watchdog_info ident = {
+		.identity = "IT8712F Watchdog",
+		.firmware_version = 1,
+		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+	};
+	int new_margin;
+
+	switch (cmd) {
+	default:
+		return -ENOTTY;
+	case WDIOC_GETSUPPORT:
+		if (copy_to_user(argp, &ident, sizeof(ident)))
+			return -EFAULT;
+		return 0;
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+	case WDIOC_KEEPALIVE:
+		it8712f_wdt_ping();
+		return 0;
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_margin, p))
+			return -EFAULT;
+		if (new_margin < 1)
+			return -EINVAL;
+		margin = new_margin;
+		superio_enter();
+		superio_select(LDN_GPIO);
+
+		it8712f_wdt_update_margin();
+
+		superio_exit();
+		it8712f_wdt_ping();
+	case WDIOC_GETTIMEOUT:
+		if (put_user(margin, p))
+			return -EFAULT;
+		return 0;
+	}
+}
+
+static int
+it8712f_wdt_open(struct inode *inode, struct file *file)
+{
+	/* only allow one at a time */
+	if (down_trylock(&it8712f_wdt_sem))
+		return -EBUSY;
+	it8712f_wdt_enable();
+
+	return nonseekable_open(inode, file);
+}
+
+static int
+it8712f_wdt_release(struct inode *inode, struct file *file)
+{
+	if (expect_close != 42) {
+		printk(KERN_WARNING NAME
+			": watchdog device closed unexpectedly, will not"
+			" disable the watchdog timer\n");
+	} else if (!nowayout) {
+		it8712f_wdt_disable();
+	}
+	expect_close = 0;
+	up(&it8712f_wdt_sem);
+
+	return 0;
+}
+
+static struct file_operations it8712f_wdt_fops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.write = it8712f_wdt_write,
+	.ioctl = it8712f_wdt_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;
+
+	superio_enter();
+	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)) {
+		printk(KERN_ERR NAME ": Device not activated, skipping\n");
+		goto exit;
+	}
+
+	*address = superio_inw(BASE_REG);
+	if (*address == 0) {
+		printk(KERN_ERR NAME ": Base address not set, skipping\n");
+		goto exit;
+	}
+
+	err = 0;
+	printk(KERN_DEBUG NAME ": Found IT%04xF chip revision %d - "
+		"using DogFood address 0x%x\n",
+		chip_type, superio_inb(DEVREV) & 0x0f, *address);
+
+exit:
+	superio_exit();
+	return err;
+}
+
+static int __init
+it8712f_wdt_init(void)
+{
+	int err = 0;
+
+	spin_lock_init(&io_lock);
+
+	if (it8712f_wdt_find(&address))
+		return -ENODEV;
+
+	if (!request_region(address, 1, "IT8712F Watchdog")) {
+		printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
+		return -EBUSY;
+	}
+
+	it8712f_wdt_disable();
+
+	sema_init(&it8712f_wdt_sem, 1);
+
+	err = register_reboot_notifier(&it8712f_wdt_notifier);
+	if (err) {
+		printk(KERN_ERR NAME ": unable to register reboot notifier\n");
+		goto out;
+	}
+
+	err = misc_register(&it8712f_wdt_miscdev);
+	if (err) {
+		printk(KERN_ERR NAME
+			": 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);