310 lines
6.6 KiB
C
310 lines
6.6 KiB
C
/* Watchdog timer for the Geode GX/LX with the CS5535/CS5536 companion chip
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*
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* Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/fs.h>
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#include <linux/platform_device.h>
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#include <linux/reboot.h>
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#include <asm/uaccess.h>
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#include <asm/geode.h>
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#define GEODEWDT_HZ 500
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#define GEODEWDT_SCALE 6
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#define GEODEWDT_MAX_SECONDS 131
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#define WDT_FLAGS_OPEN 1
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#define WDT_FLAGS_ORPHAN 2
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#define DRV_NAME "geodewdt"
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#define WATCHDOG_NAME "Geode GX/LX WDT"
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#define WATCHDOG_TIMEOUT 60
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static int timeout = WATCHDOG_TIMEOUT;
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=131, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
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static int nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static struct platform_device *geodewdt_platform_device;
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static unsigned long wdt_flags;
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static int wdt_timer;
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static int safe_close;
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static void geodewdt_ping(void)
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{
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/* Stop the counter */
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geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
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/* Reset the counter */
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geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
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/* Enable the counter */
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geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
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}
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static void geodewdt_disable(void)
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{
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geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
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geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
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}
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static int geodewdt_set_heartbeat(int val)
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{
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if (val < 1 || val > GEODEWDT_MAX_SECONDS)
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return -EINVAL;
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geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
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geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
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geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
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geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
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timeout = val;
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return 0;
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}
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static int
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geodewdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
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return -EBUSY;
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if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
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__module_get(THIS_MODULE);
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geodewdt_ping();
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return nonseekable_open(inode, file);
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}
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static int
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geodewdt_release(struct inode *inode, struct file *file)
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{
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if (safe_close) {
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geodewdt_disable();
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module_put(THIS_MODULE);
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}
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else {
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printk(KERN_CRIT "Unexpected close - watchdog is not stopping.\n");
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geodewdt_ping();
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set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
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}
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clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
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safe_close = 0;
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return 0;
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}
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static ssize_t
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geodewdt_write(struct file *file, const char __user *data, size_t len,
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loff_t *ppos)
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{
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if(len) {
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if (!nowayout) {
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size_t i;
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safe_close = 0;
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for (i = 0; i != len; i++) {
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char c;
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if (get_user(c, data + i))
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return -EFAULT;
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if (c == 'V')
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safe_close = 1;
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}
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}
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geodewdt_ping();
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}
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return len;
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}
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static int
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geodewdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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int interval;
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static struct watchdog_info ident = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
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| WDIOF_MAGICCLOSE,
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.firmware_version = 1,
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.identity = WATCHDOG_NAME,
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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(argp, &ident,
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sizeof(ident)) ? -EFAULT : 0;
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break;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, p);
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case WDIOC_KEEPALIVE:
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geodewdt_ping();
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(interval, p))
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return -EFAULT;
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if (geodewdt_set_heartbeat(interval))
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return -EINVAL;
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/* Fall through */
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case WDIOC_GETTIMEOUT:
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return put_user(timeout, p);
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case WDIOC_SETOPTIONS:
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{
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int options, ret = -EINVAL;
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if (get_user(options, p))
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return -EFAULT;
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if (options & WDIOS_DISABLECARD) {
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geodewdt_disable();
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ret = 0;
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}
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if (options & WDIOS_ENABLECARD) {
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geodewdt_ping();
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ret = 0;
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}
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return ret;
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}
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default:
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return -ENOTTY;
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}
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return 0;
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}
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static const struct file_operations geodewdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = geodewdt_write,
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.ioctl = geodewdt_ioctl,
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.open = geodewdt_open,
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.release = geodewdt_release,
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};
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static struct miscdevice geodewdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &geodewdt_fops
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};
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static int __devinit
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geodewdt_probe(struct platform_device *dev)
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{
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int ret, timer;
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timer = geode_mfgpt_alloc_timer(MFGPT_TIMER_ANY,
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MFGPT_DOMAIN_WORKING, THIS_MODULE);
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if (timer == -1) {
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printk(KERN_ERR "geodewdt: No timers were available\n");
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return -ENODEV;
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}
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wdt_timer = timer;
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/* Set up the timer */
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geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
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GEODEWDT_SCALE | (3 << 8));
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/* Set up comparator 2 to reset when the event fires */
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geode_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
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/* Set up the initial timeout */
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geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
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timeout * GEODEWDT_HZ);
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ret = misc_register(&geodewdt_miscdev);
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return ret;
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}
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static int __devexit
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geodewdt_remove(struct platform_device *dev)
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{
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misc_deregister(&geodewdt_miscdev);
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return 0;
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}
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static void
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geodewdt_shutdown(struct platform_device *dev)
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{
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geodewdt_disable();
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}
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static struct platform_driver geodewdt_driver = {
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.probe = geodewdt_probe,
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.remove = __devexit_p(geodewdt_remove),
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.shutdown = geodewdt_shutdown,
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.driver = {
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.owner = THIS_MODULE,
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.name = DRV_NAME,
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},
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};
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static int __init
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geodewdt_init(void)
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{
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int ret;
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ret = platform_driver_register(&geodewdt_driver);
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if (ret)
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return ret;
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geodewdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
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if (IS_ERR(geodewdt_platform_device)) {
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ret = PTR_ERR(geodewdt_platform_device);
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goto err;
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}
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return 0;
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err:
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platform_driver_unregister(&geodewdt_driver);
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return ret;
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}
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static void __exit
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geodewdt_exit(void)
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{
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platform_device_unregister(geodewdt_platform_device);
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platform_driver_unregister(&geodewdt_driver);
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}
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module_init(geodewdt_init);
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module_exit(geodewdt_exit);
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MODULE_AUTHOR("Advanced Micro Devices, Inc");
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MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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