[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 <jorge@dti2.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 400 insertions, 0 deletions

diff --git a/drivers/watchdog/it8712f_wdt.c b/drivers/watchdog/it8712f_wdt.c
new file mode 100644
index 000000000000..6330fc02464e
--- /dev/null
+++ b/drivers/watchdog/it8712f_wdt.c
@@ -0,0 +1,400 @@
+/*
+ *      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 0.9.2.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 <jorge@dti2.net>");
+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);