--- /dev/null
+/* 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:
+*/
git.samba.org / sfrench / cifs-2.6.git / blobdiff