1 files changed, 269 insertions, 0 deletions

diff --git a/drivers/watchdog/scx200_wdt.c b/drivers/watchdog/scx200_wdt.c
new file mode 100644
index 000000000000..d4fd0fa2f176
--- /dev/null
+++ b/drivers/watchdog/scx200_wdt.c
@@ -0,0 +1,269 @@
+/* drivers/char/watchdog/scx200_wdt.c
+
+   National Semiconductor SCx200 Watchdog support
+
+   Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
+
+   Some code taken from:
+   National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
+   (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>
+
+   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/ioport.h>
+#include <linux/scx200.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#define NAME "scx200_wdt"
+
+MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
+MODULE_DESCRIPTION("NatSemi SCx200 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 u16 wdto_restart;
+static struct semaphore open_semaphore;
+static char expect_close;
+
+/* Bits of the WDCNFG register */
+#define W_ENABLE 0x00fa         /* Enable watchdog */
+#define W_DISABLE 0x0000        /* Disable watchdog */
+
+/* The scaling factor for the timer, this depends on the value of W_ENABLE */
+#define W_SCALE (32768/1024)
+
+static void scx200_wdt_ping(void)
+{
+        outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
+}
+
+static void scx200_wdt_update_margin(void)
+{
+        printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
+        wdto_restart = margin * W_SCALE;
+}
+
+static void scx200_wdt_enable(void)
+{
+        printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n",
+               wdto_restart);
+
+        outw(0, scx200_cb_base + SCx200_WDT_WDTO);
+        outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
+        outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
+
+        scx200_wdt_ping();
+}
+
+static void scx200_wdt_disable(void)
+{
+        printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
+
+        outw(0, scx200_cb_base + SCx200_WDT_WDTO);
+        outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
+        outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
+}
+
+static int scx200_wdt_open(struct inode *inode, struct file *file)
+{
+        /* only allow one at a time */
+        if (down_trylock(&open_semaphore))
+                return -EBUSY;
+        scx200_wdt_enable();
+
+        return nonseekable_open(inode, file);
+}
+
+static int scx200_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) {
+                scx200_wdt_disable();
+        }
+        expect_close = 0;
+        up(&open_semaphore);
+
+        return 0;
+}
+
+static int scx200_wdt_notify_sys(struct notifier_block *this,
+                                      unsigned long code, void *unused)
+{
+        if (code == SYS_HALT || code == SYS_POWER_OFF)
+                if (!nowayout)
+                        scx200_wdt_disable();
+
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block scx200_wdt_notifier =
+{
+        .notifier_call = scx200_wdt_notify_sys,
+};
+
+static ssize_t scx200_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;
+
+                scx200_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;
+        }
+
+        return 0;
+}
+
+static int scx200_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 = "NatSemi SCx200 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:
+                if (put_user(0, p))
+                        return -EFAULT;
+                return 0;
+        case WDIOC_KEEPALIVE:
+                scx200_wdt_ping();
+                return 0;
+        case WDIOC_SETTIMEOUT:
+                if (get_user(new_margin, p))
+                        return -EFAULT;
+                if (new_margin < 1)
+                        return -EINVAL;
+                margin = new_margin;
+                scx200_wdt_update_margin();
+                scx200_wdt_ping();
+        case WDIOC_GETTIMEOUT:
+                if (put_user(margin, p))
+                        return -EFAULT;
+                return 0;
+        }
+}
+
+static const struct file_operations scx200_wdt_fops = {
+        .owner   = THIS_MODULE,
+        .llseek  = no_llseek,
+        .write   = scx200_wdt_write,
+        .ioctl   = scx200_wdt_ioctl,
+        .open    = scx200_wdt_open,
+        .release = scx200_wdt_release,
+};
+
+static struct miscdevice scx200_wdt_miscdev = {
+        .minor = WATCHDOG_MINOR,
+        .name  = "watchdog",
+        .fops  = &scx200_wdt_fops,
+};
+
+static int __init scx200_wdt_init(void)
+{
+        int r;
+
+        printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
+
+        /* check that we have found the configuration block */
+        if (!scx200_cb_present())
+                return -ENODEV;
+
+        if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
+                            SCx200_WDT_SIZE,
+                            "NatSemi SCx200 Watchdog")) {
+                printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
+                return -EBUSY;
+        }
+
+        scx200_wdt_update_margin();
+        scx200_wdt_disable();
+
+        sema_init(&open_semaphore, 1);
+
+        r = misc_register(&scx200_wdt_miscdev);
+        if (r) {
+                release_region(scx200_cb_base + SCx200_WDT_OFFSET,
+                                SCx200_WDT_SIZE);
+                return r;
+        }
+
+        r = register_reboot_notifier(&scx200_wdt_notifier);
+        if (r) {
+                printk(KERN_ERR NAME ": unable to register reboot notifier");
+                misc_deregister(&scx200_wdt_miscdev);
+                release_region(scx200_cb_base + SCx200_WDT_OFFSET,
+                                SCx200_WDT_SIZE);
+                return r;
+        }
+
+        return 0;
+}
+
+static void __exit scx200_wdt_cleanup(void)
+{
+        unregister_reboot_notifier(&scx200_wdt_notifier);
+        misc_deregister(&scx200_wdt_miscdev);
+        release_region(scx200_cb_base + SCx200_WDT_OFFSET,
+                       SCx200_WDT_SIZE);
+}
+
+module_init(scx200_wdt_init);
+module_exit(scx200_wdt_cleanup);
+
+/*
+    Local variables:
+        compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
+        c-basic-offset: 8
+    End:
+*/