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![Viresh Kumar](/assets/img/avatar_default.png)
irq is not necessary for mpcore wdt. Don't return error if it is not passed. But if it is passed, then request_irq must pass. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
457 lines
10 KiB
C
457 lines
10 KiB
C
/*
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* Watchdog driver for the mpcore watchdog timer
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*
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* (c) Copyright 2004 ARM Limited
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*
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* Based on the SoftDog driver:
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* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
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* All Rights Reserved.
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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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* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
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* warranty for any of this software. This material is provided
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* "AS-IS" and at no charge.
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*
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* (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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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/reboot.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/platform_device.h>
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#include <linux/uaccess.h>
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#include <linux/slab.h>
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#include <linux/io.h>
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#include <asm/smp_twd.h>
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struct mpcore_wdt {
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unsigned long timer_alive;
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struct device *dev;
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void __iomem *base;
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int irq;
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unsigned int perturb;
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char expect_close;
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};
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static struct platform_device *mpcore_wdt_pdev;
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static DEFINE_SPINLOCK(wdt_lock);
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#define TIMER_MARGIN 60
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static int mpcore_margin = TIMER_MARGIN;
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module_param(mpcore_margin, int, 0);
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MODULE_PARM_DESC(mpcore_margin,
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"MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default="
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__MODULE_STRING(TIMER_MARGIN) ")");
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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,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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#define ONLY_TESTING 0
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static int mpcore_noboot = ONLY_TESTING;
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module_param(mpcore_noboot, int, 0);
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MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, "
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"set to 1 to ignore reboots, 0 to reboot (default="
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__MODULE_STRING(ONLY_TESTING) ")");
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/*
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* This is the interrupt handler. Note that we only use this
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* in testing mode, so don't actually do a reboot here.
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*/
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static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
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{
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struct mpcore_wdt *wdt = arg;
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/* Check it really was our interrupt */
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if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
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dev_printk(KERN_CRIT, wdt->dev,
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"Triggered - Reboot ignored.\n");
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/* Clear the interrupt on the watchdog */
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writel(1, wdt->base + TWD_WDOG_INTSTAT);
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return IRQ_HANDLED;
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}
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return IRQ_NONE;
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}
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/*
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* mpcore_wdt_keepalive - reload the timer
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*
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* Note that the spec says a DIFFERENT value must be written to the reload
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* register each time. The "perturb" variable deals with this by adding 1
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* to the count every other time the function is called.
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*/
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static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
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{
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unsigned long count;
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spin_lock(&wdt_lock);
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/* Assume prescale is set to 256 */
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count = __raw_readl(wdt->base + TWD_WDOG_COUNTER);
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count = (0xFFFFFFFFU - count) * (HZ / 5);
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count = (count / 256) * mpcore_margin;
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/* Reload the counter */
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writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
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wdt->perturb = wdt->perturb ? 0 : 1;
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spin_unlock(&wdt_lock);
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}
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static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
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{
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spin_lock(&wdt_lock);
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writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
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writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
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writel(0x0, wdt->base + TWD_WDOG_CONTROL);
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spin_unlock(&wdt_lock);
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}
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static void mpcore_wdt_start(struct mpcore_wdt *wdt)
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{
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dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n");
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/* This loads the count register but does NOT start the count yet */
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mpcore_wdt_keepalive(wdt);
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if (mpcore_noboot) {
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/* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */
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writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
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} else {
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/* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */
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writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
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}
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}
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static int mpcore_wdt_set_heartbeat(int t)
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{
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if (t < 0x0001 || t > 0xFFFF)
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return -EINVAL;
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mpcore_margin = t;
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return 0;
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}
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/*
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* /dev/watchdog handling
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*/
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static int mpcore_wdt_open(struct inode *inode, struct file *file)
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{
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struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_pdev);
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if (test_and_set_bit(0, &wdt->timer_alive))
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return -EBUSY;
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if (nowayout)
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__module_get(THIS_MODULE);
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file->private_data = wdt;
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/*
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* Activate timer
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*/
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mpcore_wdt_start(wdt);
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return nonseekable_open(inode, file);
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}
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static int mpcore_wdt_release(struct inode *inode, struct file *file)
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{
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struct mpcore_wdt *wdt = file->private_data;
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/*
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* Shut off the timer.
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* Lock it in if it's a module and we set nowayout
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*/
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if (wdt->expect_close == 42)
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mpcore_wdt_stop(wdt);
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else {
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dev_printk(KERN_CRIT, wdt->dev,
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"unexpected close, not stopping watchdog!\n");
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mpcore_wdt_keepalive(wdt);
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}
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clear_bit(0, &wdt->timer_alive);
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wdt->expect_close = 0;
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return 0;
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}
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static ssize_t mpcore_wdt_write(struct file *file, const char *data,
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size_t len, loff_t *ppos)
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{
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struct mpcore_wdt *wdt = file->private_data;
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/*
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* Refresh the timer.
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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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/* In case it was set long ago */
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wdt->expect_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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wdt->expect_close = 42;
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}
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}
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mpcore_wdt_keepalive(wdt);
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}
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return len;
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}
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static const struct watchdog_info ident = {
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.options = WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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.identity = "MPcore Watchdog",
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};
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static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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struct mpcore_wdt *wdt = file->private_data;
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int ret;
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union {
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struct watchdog_info ident;
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int i;
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} uarg;
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if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
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return -ENOTTY;
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if (_IOC_DIR(cmd) & _IOC_WRITE) {
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ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
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if (ret)
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return -EFAULT;
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}
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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uarg.ident = ident;
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ret = 0;
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break;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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uarg.i = 0;
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ret = 0;
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break;
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case WDIOC_SETOPTIONS:
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ret = -EINVAL;
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if (uarg.i & WDIOS_DISABLECARD) {
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mpcore_wdt_stop(wdt);
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ret = 0;
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}
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if (uarg.i & WDIOS_ENABLECARD) {
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mpcore_wdt_start(wdt);
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ret = 0;
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}
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break;
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case WDIOC_KEEPALIVE:
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mpcore_wdt_keepalive(wdt);
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ret = 0;
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break;
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case WDIOC_SETTIMEOUT:
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ret = mpcore_wdt_set_heartbeat(uarg.i);
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if (ret)
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break;
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mpcore_wdt_keepalive(wdt);
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/* Fall */
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case WDIOC_GETTIMEOUT:
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uarg.i = mpcore_margin;
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ret = 0;
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break;
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default:
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return -ENOTTY;
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}
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if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
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ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
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if (ret)
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ret = -EFAULT;
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}
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return ret;
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}
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/*
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* System shutdown handler. Turn off the watchdog if we're
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* restarting or halting the system.
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*/
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static void mpcore_wdt_shutdown(struct platform_device *pdev)
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{
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struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
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if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
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mpcore_wdt_stop(wdt);
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}
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/*
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* Kernel Interfaces
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*/
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static const struct file_operations mpcore_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = mpcore_wdt_write,
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.unlocked_ioctl = mpcore_wdt_ioctl,
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.open = mpcore_wdt_open,
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.release = mpcore_wdt_release,
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};
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static struct miscdevice mpcore_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &mpcore_wdt_fops,
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};
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static int __devinit mpcore_wdt_probe(struct platform_device *pdev)
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{
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struct mpcore_wdt *wdt;
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struct resource *res;
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int ret;
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/* We only accept one device, and it must have an id of -1 */
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if (pdev->id != -1)
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return -ENODEV;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res)
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return -ENODEV;
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wdt = devm_kzalloc(&pdev->dev, sizeof(struct mpcore_wdt), GFP_KERNEL);
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if (!wdt)
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return -ENOMEM;
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wdt->dev = &pdev->dev;
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wdt->irq = platform_get_irq(pdev, 0);
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if (wdt->irq >= 0) {
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ret = devm_request_irq(wdt->dev, wdt->irq, mpcore_wdt_fire, 0,
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"mpcore_wdt", wdt);
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if (ret) {
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dev_printk(KERN_ERR, wdt->dev,
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"cannot register IRQ%d for watchdog\n",
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wdt->irq);
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return ret;
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}
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}
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wdt->base = devm_ioremap(wdt->dev, res->start, resource_size(res));
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if (!wdt->base)
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return -ENOMEM;
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mpcore_wdt_miscdev.parent = &pdev->dev;
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ret = misc_register(&mpcore_wdt_miscdev);
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if (ret) {
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dev_printk(KERN_ERR, wdt->dev,
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"cannot register miscdev on minor=%d (err=%d)\n",
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WATCHDOG_MINOR, ret);
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return ret;
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}
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mpcore_wdt_stop(wdt);
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platform_set_drvdata(pdev, wdt);
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mpcore_wdt_pdev = pdev;
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return 0;
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}
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static int __devexit mpcore_wdt_remove(struct platform_device *pdev)
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{
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platform_set_drvdata(pdev, NULL);
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misc_deregister(&mpcore_wdt_miscdev);
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mpcore_wdt_pdev = NULL;
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return 0;
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}
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#ifdef CONFIG_PM
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static int mpcore_wdt_suspend(struct platform_device *pdev, pm_message_t msg)
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{
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struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
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mpcore_wdt_stop(wdt); /* Turn the WDT off */
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return 0;
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}
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static int mpcore_wdt_resume(struct platform_device *pdev)
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{
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struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
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/* re-activate timer */
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if (test_bit(0, &wdt->timer_alive))
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mpcore_wdt_start(wdt);
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return 0;
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}
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#else
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#define mpcore_wdt_suspend NULL
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#define mpcore_wdt_resume NULL
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#endif
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/* work with hotplug and coldplug */
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MODULE_ALIAS("platform:mpcore_wdt");
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static struct platform_driver mpcore_wdt_driver = {
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.probe = mpcore_wdt_probe,
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.remove = __devexit_p(mpcore_wdt_remove),
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.suspend = mpcore_wdt_suspend,
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.resume = mpcore_wdt_resume,
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.shutdown = mpcore_wdt_shutdown,
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.driver = {
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.owner = THIS_MODULE,
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.name = "mpcore_wdt",
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},
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};
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static int __init mpcore_wdt_init(void)
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{
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/*
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* Check that the margin value is within it's range;
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* if not reset to the default
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*/
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if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
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mpcore_wdt_set_heartbeat(TIMER_MARGIN);
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pr_info("mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n",
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TIMER_MARGIN);
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}
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pr_info("MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n",
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mpcore_noboot, mpcore_margin, nowayout);
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return platform_driver_register(&mpcore_wdt_driver);
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}
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static void __exit mpcore_wdt_exit(void)
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{
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platform_driver_unregister(&mpcore_wdt_driver);
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}
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module_init(mpcore_wdt_init);
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module_exit(mpcore_wdt_exit);
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MODULE_AUTHOR("ARM Limited");
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MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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