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+/* 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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+
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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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+
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+#include <asm/uaccess.h>
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+#include <asm/geode.h>
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+
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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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+
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+#define WDT_FLAGS_OPEN 1
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+#define WDT_FLAGS_ORPHAN 2
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+
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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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+
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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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+
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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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+
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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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+
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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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+
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+ /* Reset the counter */
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+ geode_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
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+
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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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+
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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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+
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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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+
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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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+
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+ timeout = val;
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+ return 0;
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+}
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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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+
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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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+
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+ geodewdt_ping();
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+ return nonseekable_open(inode, file);
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+}
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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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+
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+ set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
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+ }
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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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+
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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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+
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+ for (i = 0; i != len; i++) {
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+ char c;
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+
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+ if (get_user(c, data + i))
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+ return -EFAULT;
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+
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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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+
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+ geodewdt_ping();
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+ }
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+ return len;
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+}
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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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+
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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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+
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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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+
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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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+
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+ case WDIOC_KEEPALIVE:
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+ geodewdt_ping();
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+ return 0;
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+
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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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+
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+ if (geodewdt_set_heartbeat(interval))
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+ return -EINVAL;
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+
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+/* Fall through */
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+
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+ case WDIOC_GETTIMEOUT:
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+ return put_user(timeout, p);
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+
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+ case WDIOC_SETOPTIONS:
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+ {
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+ int options, ret = -EINVAL;
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+
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+ if (get_user(options, p))
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+ return -EFAULT;
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+
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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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+
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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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+
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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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+
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+ return 0;
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+}
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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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+
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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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+
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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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+
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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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+
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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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+
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+ wdt_timer = timer;
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+
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+ /* Set up the timer */
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+
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+ geode_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
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+ GEODEWDT_SCALE | (3 << 8));
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+
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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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+
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+ /* Set up the initial timeout */
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+
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+ geode_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
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+ timeout * GEODEWDT_HZ);
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+
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+ ret = misc_register(&geodewdt_miscdev);
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+
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+ return ret;
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+}
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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+module_init(geodewdt_init);
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+module_exit(geodewdt_exit);
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+
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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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Linus Torvalds