303 lines
6.5 KiB
C
303 lines
6.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* NANO7240 SBC Watchdog device driver
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*
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* Based on w83877f.c by Scott Jennings,
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*
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* (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/ioport.h>
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#include <linux/jiffies.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/miscdevice.h>
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#include <linux/notifier.h>
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#include <linux/reboot.h>
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#include <linux/types.h>
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#include <linux/watchdog.h>
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#include <linux/io.h>
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#include <linux/uaccess.h>
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#include <linux/atomic.h>
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#define SBC7240_ENABLE_PORT 0x443
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#define SBC7240_DISABLE_PORT 0x043
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#define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT
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#define SBC7240_MAGIC_CHAR 'V'
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#define SBC7240_TIMEOUT 30
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#define SBC7240_MAX_TIMEOUT 255
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static int timeout = SBC7240_TIMEOUT; /* in seconds */
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
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__MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
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__MODULE_STRING(SBC7240_TIMEOUT) ")");
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
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#define SBC7240_OPEN_STATUS_BIT 0
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#define SBC7240_ENABLED_STATUS_BIT 1
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#define SBC7240_EXPECT_CLOSE_STATUS_BIT 2
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static unsigned long wdt_status;
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/*
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* Utility routines
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*/
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static void wdt_disable(void)
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{
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/* disable the watchdog */
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if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
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inb_p(SBC7240_DISABLE_PORT);
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pr_info("Watchdog timer is now disabled\n");
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}
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}
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static void wdt_enable(void)
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{
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/* enable the watchdog */
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if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
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inb_p(SBC7240_ENABLE_PORT);
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pr_info("Watchdog timer is now enabled\n");
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}
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}
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static int wdt_set_timeout(int t)
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{
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if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
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pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT);
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return -1;
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}
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/* set the timeout */
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outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
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timeout = t;
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pr_info("timeout set to %d seconds\n", t);
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return 0;
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}
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/* Whack the dog */
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static inline void wdt_keepalive(void)
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{
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if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
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inb_p(SBC7240_ENABLE_PORT);
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}
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/*
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* /dev/watchdog handling
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*/
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static ssize_t fop_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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size_t i;
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char c;
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if (count) {
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if (!nowayout) {
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clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
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&wdt_status);
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/* is there a magic char ? */
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for (i = 0; i != count; i++) {
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if (get_user(c, buf + i))
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return -EFAULT;
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if (c == SBC7240_MAGIC_CHAR) {
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set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
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&wdt_status);
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break;
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}
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}
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}
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wdt_keepalive();
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}
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return count;
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}
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static int fop_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
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return -EBUSY;
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wdt_enable();
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return stream_open(inode, file);
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}
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static int fop_close(struct inode *inode, struct file *file)
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{
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if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
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|| !nowayout) {
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wdt_disable();
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} else {
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pr_crit("Unexpected close, not stopping watchdog!\n");
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wdt_keepalive();
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}
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clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
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return 0;
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}
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static const struct watchdog_info ident = {
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.options = WDIOF_KEEPALIVEPING|
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WDIOF_SETTIMEOUT|
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WDIOF_MAGICCLOSE,
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.firmware_version = 1,
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.identity = "SBC7240",
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};
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static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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return copy_to_user((void __user *)arg, &ident, sizeof(ident))
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? -EFAULT : 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, (int __user *)arg);
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case WDIOC_SETOPTIONS:
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{
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int options;
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int retval = -EINVAL;
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if (get_user(options, (int __user *)arg))
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return -EFAULT;
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if (options & WDIOS_DISABLECARD) {
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wdt_disable();
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retval = 0;
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}
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if (options & WDIOS_ENABLECARD) {
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wdt_enable();
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retval = 0;
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}
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return retval;
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}
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case WDIOC_KEEPALIVE:
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wdt_keepalive();
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return 0;
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case WDIOC_SETTIMEOUT:
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{
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int new_timeout;
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if (get_user(new_timeout, (int __user *)arg))
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return -EFAULT;
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if (wdt_set_timeout(new_timeout))
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return -EINVAL;
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}
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/* Fall through */
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case WDIOC_GETTIMEOUT:
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return put_user(timeout, (int __user *)arg);
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default:
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return -ENOTTY;
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}
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}
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static const struct file_operations wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = fop_write,
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.open = fop_open,
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.release = fop_close,
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.unlocked_ioctl = fop_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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};
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static struct miscdevice wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &wdt_fops,
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};
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/*
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* Notifier for system down
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*/
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static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
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void *unused)
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{
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if (code == SYS_DOWN || code == SYS_HALT)
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wdt_disable();
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return NOTIFY_DONE;
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}
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static struct notifier_block wdt_notifier = {
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.notifier_call = wdt_notify_sys,
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};
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static void __exit sbc7240_wdt_unload(void)
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{
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pr_info("Removing watchdog\n");
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misc_deregister(&wdt_miscdev);
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unregister_reboot_notifier(&wdt_notifier);
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release_region(SBC7240_ENABLE_PORT, 1);
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}
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static int __init sbc7240_wdt_init(void)
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{
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int rc = -EBUSY;
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if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
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pr_err("I/O address 0x%04x already in use\n",
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SBC7240_ENABLE_PORT);
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rc = -EIO;
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goto err_out;
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}
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/* The IO port 0x043 used to disable the watchdog
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* is already claimed by the system timer, so we
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* can't request_region() it ...*/
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if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
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timeout = SBC7240_TIMEOUT;
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pr_info("timeout value must be 1<=x<=%d, using %d\n",
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SBC7240_MAX_TIMEOUT, timeout);
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}
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wdt_set_timeout(timeout);
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wdt_disable();
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rc = register_reboot_notifier(&wdt_notifier);
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if (rc) {
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pr_err("cannot register reboot notifier (err=%d)\n", rc);
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goto err_out_region;
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}
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rc = misc_register(&wdt_miscdev);
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if (rc) {
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pr_err("cannot register miscdev on minor=%d (err=%d)\n",
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wdt_miscdev.minor, rc);
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goto err_out_reboot_notifier;
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}
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pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
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nowayout);
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return 0;
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err_out_reboot_notifier:
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unregister_reboot_notifier(&wdt_notifier);
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err_out_region:
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release_region(SBC7240_ENABLE_PORT, 1);
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err_out:
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return rc;
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}
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module_init(sbc7240_wdt_init);
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module_exit(sbc7240_wdt_unload);
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MODULE_AUTHOR("Gilles Gigan");
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MODULE_DESCRIPTION("Watchdog device driver for single board"
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" computers EPIC Nano 7240 from iEi");
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MODULE_LICENSE("GPL");
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