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@@ -0,0 +1,490 @@
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+/*
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+ * Blackfin On-Chip Watchdog Driver
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+ * Supports BF53[123]/BF53[467]/BF54[2489]/BF561
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+ *
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+ * Originally based on softdog.c
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+ * Copyright 2006-2007 Analog Devices Inc.
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+ * Copyright 2006-2007 Michele d'Amico
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+ * Copyright 1996 Alan Cox <alan@redhat.com>
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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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+
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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/notifier.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 <asm/blackfin.h>
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+#include <asm/uaccess.h>
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+
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+#define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
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+#define stampit() stamp("here i am")
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+
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+#define WATCHDOG_NAME "bfin-wdt"
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+#define PFX WATCHDOG_NAME ": "
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+
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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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+
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+/* Bit in SWRST that indicates boot caused by watchdog */
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+#define SWRST_RESET_WDOG 0x4000
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+
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+/* Bit in WDOG_CTL that indicates watchdog has expired (WDR0) */
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+#define WDOG_EXPIRED 0x8000
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+
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+/* Masks for WDEV field in WDOG_CTL register */
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+#define ICTL_RESET 0x0
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+#define ICTL_NMI 0x2
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+#define ICTL_GPI 0x4
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+#define ICTL_NONE 0x6
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+#define ICTL_MASK 0x6
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+
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+/* Masks for WDEN field in WDOG_CTL register */
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+#define WDEN_MASK 0x0FF0
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+#define WDEN_ENABLE 0x0000
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+#define WDEN_DISABLE 0x0AD0
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+
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+/* some defaults */
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+#define WATCHDOG_TIMEOUT 20
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+
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+static unsigned int timeout = WATCHDOG_TIMEOUT;
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+static int nowayout = WATCHDOG_NOWAYOUT;
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+static 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 spinlock_t bfin_wdt_spinlock = SPIN_LOCK_UNLOCKED;
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+
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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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+/**
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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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+/**
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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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+/**
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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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+/**
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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;
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+ unsigned long flags;
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+
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+ stampit();
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+
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+ cnt = t * get_sclk();
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+ if (cnt < get_sclk()) {
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+ printk(KERN_WARNING PFX "timeout value is too large\n");
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+ return -EINVAL;
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+ }
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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) bfin_wdt_start();
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+ }
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+ spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
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+
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+ timeout = t;
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+
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+ return 0;
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+}
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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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+
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+ if (test_and_set_bit(0, &open_check))
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+ return -EBUSY;
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+
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+ if (nowayout)
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+ __module_get(THIS_MODULE);
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+
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+ bfin_wdt_keepalive();
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+ bfin_wdt_start();
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+
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+ return nonseekable_open(inode, file);
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+}
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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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+
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+ if (expect_close == 42) {
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+ bfin_wdt_stop();
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+ } else {
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+ printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
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+ bfin_wdt_keepalive();
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+ }
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+
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+ expect_close = 0;
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+ clear_bit(0, &open_check);
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+
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+ return 0;
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+}
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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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+
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+ if (len) {
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+ if (!nowayout) {
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+ size_t i;
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+
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+ /* In case it was set long ago */
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+ expect_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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+ 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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+
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+ return len;
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+}
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+
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+/**
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+ * bfin_wdt_ioctl - Query Device
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+ * @inode: inode of 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 int bfin_wdt_ioctl(struct inode *inode, 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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+
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+ stampit();
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+
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+ switch (cmd) {
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+ default:
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+ return -ENOTTY;
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+
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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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+
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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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+
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+ case WDIOC_KEEPALIVE:
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+ bfin_wdt_keepalive();
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+ return 0;
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+
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+ case WDIOC_SETTIMEOUT: {
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+ int new_timeout;
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+
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+ if (get_user(new_timeout, p))
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+ return -EFAULT;
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+
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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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+
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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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+
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+ if (get_user(options, p))
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+ return -EFAULT;
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+
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+ spin_lock_irqsave(&bfin_wdt_spinlock, flags);
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+
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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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+
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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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+
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+ spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
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+
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+ return ret;
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+ }
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+ }
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+}
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+
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+/**
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+ * bfin_wdt_notify_sys - Notifier Handler
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+ * @this: notifier block
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+ * @code: notifier event
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+ * @unused: unused
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+ *
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+ * Handles specific events, such as turning off the watchdog during a
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+ * shutdown event.
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+ */
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+static int bfin_wdt_notify_sys(struct notifier_block *this, unsigned long code,
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+ void *unused)
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+{
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+ stampit();
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+
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+ if (code == SYS_DOWN || code == SYS_HALT)
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+ bfin_wdt_stop();
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+
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+ return NOTIFY_DONE;
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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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+/**
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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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+
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+ state_before_suspend = bfin_wdt_running();
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+ bfin_wdt_stop();
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+
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+ return 0;
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+}
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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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+
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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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+
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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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+
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+static struct platform_device bfin_wdt_device = {
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+ .name = WATCHDOG_NAME,
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+ .id = -1,
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+};
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+
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+static struct platform_driver bfin_wdt_driver = {
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+ .driver = {
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+ .name = WATCHDOG_NAME,
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+ .owner = THIS_MODULE,
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+ },
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+ .suspend = bfin_wdt_suspend,
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+ .resume = bfin_wdt_resume,
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+};
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+
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+static 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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+ .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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+
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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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+
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+static 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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+static struct notifier_block bfin_wdt_notifier = {
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+ .notifier_call = bfin_wdt_notify_sys,
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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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+ * Registers the device and notifier handler. Actual device
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+ * initialization is handled by bfin_wdt_open().
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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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+
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+ stampit();
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+
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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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+
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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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|
|
+ */
|
|
|
+ ret = platform_device_register(&bfin_wdt_device);
|
|
|
+ if (ret)
|
|
|
+ return ret;
|
|
|
+
|
|
|
+ ret = platform_driver_probe(&bfin_wdt_driver, NULL);
|
|
|
+ if (ret)
|
|
|
+ return ret;
|
|
|
+
|
|
|
+ ret = register_reboot_notifier(&bfin_wdt_notifier);
|
|
|
+ if (ret) {
|
|
|
+ printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", ret);
|
|
|
+ return ret;
|
|
|
+ }
|
|
|
+
|
|
|
+ ret = misc_register(&bfin_wdt_miscdev);
|
|
|
+ if (ret) {
|
|
|
+ printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
|
|
|
+ WATCHDOG_MINOR, ret);
|
|
|
+ unregister_reboot_notifier(&bfin_wdt_notifier);
|
|
|
+ return ret;
|
|
|
+ }
|
|
|
+
|
|
|
+ printk(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
|
|
|
+ timeout, nowayout);
|
|
|
+
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+
|
|
|
+/**
|
|
|
+ * bfin_wdt_exit - Deinitialize module
|
|
|
+ *
|
|
|
+ * Unregisters the device and notifier handler. Actual device
|
|
|
+ * deinitialization is handled by bfin_wdt_close().
|
|
|
+ */
|
|
|
+static void __exit bfin_wdt_exit(void)
|
|
|
+{
|
|
|
+ misc_deregister(&bfin_wdt_miscdev);
|
|
|
+ unregister_reboot_notifier(&bfin_wdt_notifier);
|
|
|
+}
|
|
|
+
|
|
|
+module_init(bfin_wdt_init);
|
|
|
+module_exit(bfin_wdt_exit);
|
|
|
+
|
|
|
+MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>");
|
|
|
+MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
|
|
|
+MODULE_LICENSE("GPL");
|
|
|
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|
|
|
+
|
|
|
+module_param(timeout, uint, 0);
|
|
|
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
|
|
|
+
|
|
|
+module_param(nowayout, int, 0);
|
|
|
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
|