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fa21a580de
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
477 lines
10 KiB
C
477 lines
10 KiB
C
/*
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* Blackfin On-Chip Watchdog Driver
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*
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* Originally based on softdog.c
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* Copyright 2006-2010 Analog Devices Inc.
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* Copyright 2006-2007 Michele d'Amico
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* Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>
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*
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* Enter bugs at http://blackfin.uclinux.org/
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*
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* Licensed under the GPL-2 or later.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/platform_device.h>
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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/timer.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/init.h>
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#include <linux/interrupt.h>
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#include <linux/uaccess.h>
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#include <asm/blackfin.h>
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#include <asm/bfin_watchdog.h>
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#define stamp(fmt, args...) \
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pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
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#define stampit() stamp("here i am")
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#define WATCHDOG_NAME "bfin-wdt"
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/* The BF561 has two watchdogs (one per core), but since Linux
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* only runs on core A, we'll just work with that one.
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*/
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#ifdef BF561_FAMILY
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# define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL()
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# define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT()
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# define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT()
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# define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x)
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# define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x)
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# define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
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#endif
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/* some defaults */
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#define WATCHDOG_TIMEOUT 20
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static unsigned int timeout = WATCHDOG_TIMEOUT;
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static bool nowayout = WATCHDOG_NOWAYOUT;
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static const struct watchdog_info bfin_wdt_info;
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static unsigned long open_check;
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static char expect_close;
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static DEFINE_SPINLOCK(bfin_wdt_spinlock);
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/**
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* bfin_wdt_keepalive - Keep the Userspace Watchdog Alive
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*
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* The Userspace watchdog got a KeepAlive: schedule the next timeout.
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*/
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static int bfin_wdt_keepalive(void)
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{
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stampit();
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bfin_write_WDOG_STAT(0);
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return 0;
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}
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/**
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* bfin_wdt_stop - Stop the Watchdog
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*
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* Stops the on-chip watchdog.
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*/
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static int bfin_wdt_stop(void)
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{
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stampit();
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bfin_write_WDOG_CTL(WDEN_DISABLE);
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return 0;
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}
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/**
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* bfin_wdt_start - Start the Watchdog
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*
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* Starts the on-chip watchdog. Automatically loads WDOG_CNT
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* into WDOG_STAT for us.
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*/
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static int bfin_wdt_start(void)
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{
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stampit();
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bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET);
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return 0;
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}
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/**
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* bfin_wdt_running - Check Watchdog status
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*
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* See if the watchdog is running.
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*/
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static int bfin_wdt_running(void)
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{
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stampit();
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return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
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}
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/**
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* bfin_wdt_set_timeout - Set the Userspace Watchdog timeout
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* @t: new timeout value (in seconds)
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*
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* Translate the specified timeout in seconds into System Clock
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* terms which is what the on-chip Watchdog requires.
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*/
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static int bfin_wdt_set_timeout(unsigned long t)
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{
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u32 cnt, max_t, sclk;
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unsigned long flags;
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sclk = get_sclk();
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max_t = -1 / sclk;
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cnt = t * sclk;
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stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt);
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if (t > max_t) {
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pr_warn("timeout value is too large\n");
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return -EINVAL;
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}
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spin_lock_irqsave(&bfin_wdt_spinlock, flags);
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{
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int run = bfin_wdt_running();
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bfin_wdt_stop();
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bfin_write_WDOG_CNT(cnt);
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if (run)
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bfin_wdt_start();
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}
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spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
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timeout = t;
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return 0;
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}
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/**
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* bfin_wdt_open - Open the Device
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* @inode: inode of device
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* @file: file handle of device
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*
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* Watchdog device is opened and started.
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*/
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static int bfin_wdt_open(struct inode *inode, struct file *file)
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{
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stampit();
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if (test_and_set_bit(0, &open_check))
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return -EBUSY;
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if (nowayout)
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__module_get(THIS_MODULE);
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bfin_wdt_keepalive();
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bfin_wdt_start();
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return nonseekable_open(inode, file);
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}
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/**
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* bfin_wdt_close - Close the Device
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* @inode: inode of device
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* @file: file handle of device
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*
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* Watchdog device is closed and stopped.
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*/
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static int bfin_wdt_release(struct inode *inode, struct file *file)
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{
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stampit();
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if (expect_close == 42)
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bfin_wdt_stop();
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else {
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pr_crit("Unexpected close, not stopping watchdog!\n");
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bfin_wdt_keepalive();
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}
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expect_close = 0;
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clear_bit(0, &open_check);
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return 0;
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}
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/**
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* bfin_wdt_write - Write to Device
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* @file: file handle of device
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* @buf: buffer to write
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* @count: length of buffer
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* @ppos: offset
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*
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* Pings the watchdog on write.
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*/
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static ssize_t bfin_wdt_write(struct file *file, const char __user *data,
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size_t len, loff_t *ppos)
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{
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stampit();
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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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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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expect_close = 42;
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}
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}
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bfin_wdt_keepalive();
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}
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return len;
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}
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/**
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* bfin_wdt_ioctl - Query Device
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* @file: file handle of device
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* @cmd: watchdog command
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* @arg: argument
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*
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* Query basic information from the device or ping it, as outlined by the
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* watchdog API.
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*/
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static long bfin_wdt_ioctl(struct file *file,
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unsigned int cmd, 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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stampit();
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info)))
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return -EFAULT;
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else
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return 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p);
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case WDIOC_SETOPTIONS: {
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unsigned long flags;
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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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spin_lock_irqsave(&bfin_wdt_spinlock, flags);
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if (options & WDIOS_DISABLECARD) {
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bfin_wdt_stop();
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ret = 0;
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}
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if (options & WDIOS_ENABLECARD) {
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bfin_wdt_start();
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ret = 0;
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}
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spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
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return ret;
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}
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case WDIOC_KEEPALIVE:
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bfin_wdt_keepalive();
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return 0;
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case WDIOC_SETTIMEOUT: {
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int new_timeout;
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if (get_user(new_timeout, p))
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return -EFAULT;
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if (bfin_wdt_set_timeout(new_timeout))
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return -EINVAL;
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}
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/* Fall */
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case WDIOC_GETTIMEOUT:
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return put_user(timeout, p);
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default:
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return -ENOTTY;
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}
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}
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#ifdef CONFIG_PM
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static int state_before_suspend;
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/**
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* bfin_wdt_suspend - suspend the watchdog
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* @pdev: device being suspended
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* @state: requested suspend state
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*
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* Remember if the watchdog was running and stop it.
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* TODO: is this even right? Doesn't seem to be any
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* standard in the watchdog world ...
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*/
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static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state)
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{
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stampit();
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state_before_suspend = bfin_wdt_running();
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bfin_wdt_stop();
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return 0;
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}
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/**
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* bfin_wdt_resume - resume the watchdog
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* @pdev: device being resumed
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*
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* If the watchdog was running, turn it back on.
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*/
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static int bfin_wdt_resume(struct platform_device *pdev)
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{
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stampit();
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if (state_before_suspend) {
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bfin_wdt_set_timeout(timeout);
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bfin_wdt_start();
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}
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return 0;
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}
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#else
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# define bfin_wdt_suspend NULL
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# define bfin_wdt_resume NULL
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#endif
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static const struct file_operations bfin_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = bfin_wdt_write,
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.unlocked_ioctl = bfin_wdt_ioctl,
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.open = bfin_wdt_open,
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.release = bfin_wdt_release,
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};
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static struct miscdevice bfin_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &bfin_wdt_fops,
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};
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static const struct watchdog_info bfin_wdt_info = {
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.identity = "Blackfin Watchdog",
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.options = WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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};
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/**
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* bfin_wdt_probe - Initialize module
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*
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* Registers the misc device. Actual device
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* initialization is handled by bfin_wdt_open().
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*/
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static int bfin_wdt_probe(struct platform_device *pdev)
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{
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int ret;
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ret = misc_register(&bfin_wdt_miscdev);
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if (ret) {
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pr_err("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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pr_info("initialized: timeout=%d sec (nowayout=%d)\n",
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timeout, nowayout);
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return 0;
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}
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/**
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* bfin_wdt_remove - Initialize module
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*
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* Unregisters the misc device. Actual device
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* deinitialization is handled by bfin_wdt_close().
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*/
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static int bfin_wdt_remove(struct platform_device *pdev)
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{
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misc_deregister(&bfin_wdt_miscdev);
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return 0;
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}
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/**
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* bfin_wdt_shutdown - Soft Shutdown Handler
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*
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* Handles the soft shutdown event.
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*/
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static void bfin_wdt_shutdown(struct platform_device *pdev)
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{
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stampit();
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bfin_wdt_stop();
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}
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static struct platform_device *bfin_wdt_device;
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static struct platform_driver bfin_wdt_driver = {
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.probe = bfin_wdt_probe,
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.remove = bfin_wdt_remove,
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.shutdown = bfin_wdt_shutdown,
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.suspend = bfin_wdt_suspend,
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.resume = bfin_wdt_resume,
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.driver = {
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.name = WATCHDOG_NAME,
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},
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};
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/**
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* bfin_wdt_init - Initialize module
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*
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* Checks the module params and registers the platform device & driver.
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* Real work is in the platform probe function.
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*/
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static int __init bfin_wdt_init(void)
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{
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int ret;
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stampit();
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/* Check that the timeout value is within range */
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if (bfin_wdt_set_timeout(timeout))
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return -EINVAL;
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/* Since this is an on-chip device and needs no board-specific
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* resources, we'll handle all the platform device stuff here.
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*/
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ret = platform_driver_register(&bfin_wdt_driver);
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if (ret) {
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pr_err("unable to register driver\n");
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return ret;
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}
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bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME,
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-1, NULL, 0);
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if (IS_ERR(bfin_wdt_device)) {
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pr_err("unable to register device\n");
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platform_driver_unregister(&bfin_wdt_driver);
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return PTR_ERR(bfin_wdt_device);
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}
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return 0;
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}
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/**
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* bfin_wdt_exit - Deinitialize module
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*
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* Back out the platform device & driver steps. Real work is in the
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* platform remove function.
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*/
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static void __exit bfin_wdt_exit(void)
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{
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platform_device_unregister(bfin_wdt_device);
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platform_driver_unregister(&bfin_wdt_driver);
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}
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module_init(bfin_wdt_init);
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module_exit(bfin_wdt_exit);
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MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>");
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MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
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MODULE_LICENSE("GPL");
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module_param(timeout, uint, 0);
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MODULE_PARM_DESC(timeout,
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"Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
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__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
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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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