437 lines
11 KiB
Diff
437 lines
11 KiB
Diff
From 34844524c88edbb0fd75339fd655f6b69b221b0a Mon Sep 17 00:00:00 2001
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From: popcornmix <popcornmix@gmail.com>
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Date: Wed, 1 May 2013 19:54:32 +0100
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Subject: [PATCH 003/196] bcm2708 watchdog driver
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Signed-off-by: popcornmix <popcornmix@gmail.com>
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---
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drivers/watchdog/Kconfig | 6 +
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drivers/watchdog/Makefile | 1 +
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drivers/watchdog/bcm2708_wdog.c | 385 ++++++++++++++++++++++++++++++++++++++++
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3 files changed, 392 insertions(+)
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create mode 100644 drivers/watchdog/bcm2708_wdog.c
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diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
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index e89fc31..60ca320 100644
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--- a/drivers/watchdog/Kconfig
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+++ b/drivers/watchdog/Kconfig
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@@ -391,6 +391,12 @@ config RETU_WATCHDOG
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To compile this driver as a module, choose M here: the
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module will be called retu_wdt.
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+config BCM2708_WDT
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+ tristate "BCM2708 Watchdog"
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+ depends on ARCH_BCM2708
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+ help
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+ Enables BCM2708 watchdog support.
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+
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# AVR32 Architecture
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config AT32AP700X_WDT
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diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
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index a300b94..0e357711 100644
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--- a/drivers/watchdog/Makefile
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+++ b/drivers/watchdog/Makefile
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@@ -54,6 +54,7 @@ obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
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obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
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obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
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obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
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+obj-$(CONFIG_BCM2708_WDT) += bcm2708_wdog.o
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# AVR32 Architecture
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obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
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diff --git a/drivers/watchdog/bcm2708_wdog.c b/drivers/watchdog/bcm2708_wdog.c
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new file mode 100644
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index 0000000..dd33c35
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--- /dev/null
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+++ b/drivers/watchdog/bcm2708_wdog.c
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@@ -0,0 +1,385 @@
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+/*
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+ * Broadcom BCM2708 watchdog driver.
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+ *
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+ * (c) Copyright 2010 Broadcom Europe Ltd
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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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+ * BCM2708 watchdog driver. Loosely based on wdt driver.
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+ */
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+
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+#include <linux/interrupt.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/miscdevice.h>
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+#include <linux/watchdog.h>
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+#include <linux/fs.h>
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+#include <linux/ioport.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/io.h>
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+#include <linux/uaccess.h>
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+#include <mach/platform.h>
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+
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+#include <asm/system.h>
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+
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+#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
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+#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
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+
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+static unsigned long wdog_is_open;
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+static uint32_t wdog_ticks; /* Ticks to load into wdog timer */
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+static char expect_close;
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+
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+/*
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+ * Module parameters
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+ */
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+
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+#define WD_TIMO 10 /* Default heartbeat = 60 seconds */
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+static int heartbeat = WD_TIMO; /* Heartbeat in seconds */
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+
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+module_param(heartbeat, int, 0);
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+MODULE_PARM_DESC(heartbeat,
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+ "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
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+ __MODULE_STRING(WD_TIMO) ")");
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+
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+static int nowayout = WATCHDOG_NOWAYOUT;
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+module_param(nowayout, int, 0);
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+MODULE_PARM_DESC(nowayout,
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+ "Watchdog cannot be stopped once started (default="
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+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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+
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+static DEFINE_SPINLOCK(wdog_lock);
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+
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+/**
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+ * Start the watchdog driver.
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+ */
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+
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+static int wdog_start(unsigned long timeout)
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+{
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+ uint32_t cur;
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+ unsigned long flags;
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+ spin_lock_irqsave(&wdog_lock, flags);
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+
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+ /* enable the watchdog */
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+ iowrite32(PM_PASSWORD | (timeout & PM_WDOG_TIME_SET),
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+ __io_address(PM_WDOG));
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+ cur = ioread32(__io_address(PM_RSTC));
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+ iowrite32(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
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+ PM_RSTC_WRCFG_FULL_RESET, __io_address(PM_RSTC));
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+
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+ spin_unlock_irqrestore(&wdog_lock, flags);
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+ return 0;
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+}
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+
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+/**
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+ * Stop the watchdog driver.
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+ */
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+
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+static int wdog_stop(void)
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+{
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+ iowrite32(PM_PASSWORD | PM_RSTC_RESET, __io_address(PM_RSTC));
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+ printk(KERN_INFO "watchdog stopped\n");
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+ return 0;
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+}
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+
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+/**
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+ * Reload counter one with the watchdog heartbeat. We don't bother
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+ * reloading the cascade counter.
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+ */
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+
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+static void wdog_ping(void)
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+{
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+ wdog_start(wdog_ticks);
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+}
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+
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+/**
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+ * @t: the new heartbeat value that needs to be set.
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+ *
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+ * Set a new heartbeat value for the watchdog device. If the heartbeat
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+ * value is incorrect we keep the old value and return -EINVAL. If
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+ * successful we return 0.
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+ */
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+
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+static int wdog_set_heartbeat(int t)
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+{
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+ if (t < 1 || t > WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET))
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+ return -EINVAL;
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+
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+ heartbeat = t;
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+ wdog_ticks = SECS_TO_WDOG_TICKS(t);
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+ return 0;
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+}
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+
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+/**
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+ * @file: file handle to the watchdog
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+ * @buf: buffer to write (unused as data does not matter here
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+ * @count: count of bytes
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+ * @ppos: pointer to the position to write. No seeks allowed
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+ *
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+ * A write to a watchdog device is defined as a keepalive signal.
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+ *
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+ * if 'nowayout' is set then normally a close() is ignored. But
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+ * if you write 'V' first then the close() will stop the timer.
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+ */
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+
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+static ssize_t wdog_write(struct file *file, const char __user *buf,
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+ size_t count, loff_t *ppos)
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+{
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+ if (count) {
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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 != count; i++) {
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+ char c;
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+ if (get_user(c, buf + 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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+ wdog_ping();
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+ }
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+ return count;
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+}
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+
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+static int wdog_get_status(void)
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+{
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+ unsigned long flags;
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+ int status = 0;
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+ spin_lock_irqsave(&wdog_lock, flags);
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+ /* FIXME: readback reset reason */
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+ spin_unlock_irqrestore(&wdog_lock, flags);
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+ return status;
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+}
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+
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+static uint32_t wdog_get_remaining(void)
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+{
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+ uint32_t ret = ioread32(__io_address(PM_WDOG));
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+ return ret & PM_WDOG_TIME_SET;
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+}
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+
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+/**
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+ * @file: file handle to the device
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+ * @cmd: watchdog command
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+ * @arg: argument pointer
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+ *
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+ * The watchdog API defines a common set of functions for all watchdogs
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+ * according to their available features. We only actually usefully support
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+ * querying capabilities and current status.
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+ */
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+
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+static long wdog_ioctl(struct file *file, 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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+ int new_heartbeat;
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+ int status;
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+ int options;
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+ uint32_t remaining;
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+
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+ struct watchdog_info ident = {
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+ .options = WDIOF_SETTIMEOUT|
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+ WDIOF_MAGICCLOSE|
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+ WDIOF_KEEPALIVEPING,
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+ .firmware_version = 1,
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+ .identity = "BCM2708",
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+ };
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+
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+ switch (cmd) {
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+ case WDIOC_GETSUPPORT:
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+ return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
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+ case WDIOC_GETSTATUS:
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+ status = wdog_get_status();
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+ return put_user(status, p);
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+ case WDIOC_GETBOOTSTATUS:
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+ return put_user(0, p);
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+ case WDIOC_KEEPALIVE:
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+ wdog_ping();
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+ return 0;
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+ case WDIOC_SETTIMEOUT:
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+ if (get_user(new_heartbeat, p))
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+ return -EFAULT;
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+ if (wdog_set_heartbeat(new_heartbeat))
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+ return -EINVAL;
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+ wdog_ping();
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+ /* Fall */
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+ case WDIOC_GETTIMEOUT:
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+ return put_user(heartbeat, p);
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+ case WDIOC_GETTIMELEFT:
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+ remaining = WDOG_TICKS_TO_SECS(wdog_get_remaining());
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+ return put_user(remaining, p);
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+ case WDIOC_SETOPTIONS:
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+ if (get_user(options, p))
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+ return -EFAULT;
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+ if (options & WDIOS_DISABLECARD)
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+ wdog_stop();
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+ if (options & WDIOS_ENABLECARD)
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+ wdog_start(wdog_ticks);
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+ return 0;
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+ default:
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+ return -ENOTTY;
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+ }
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+}
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+
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+/**
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+ * @inode: inode of device
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+ * @file: file handle to device
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+ *
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+ * The watchdog device has been opened. The watchdog device is single
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+ * open and on opening we load the counters.
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+ */
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+
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+static int wdog_open(struct inode *inode, struct file *file)
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+{
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+ if (test_and_set_bit(0, &wdog_is_open))
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+ return -EBUSY;
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+ /*
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+ * Activate
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+ */
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+ wdog_start(wdog_ticks);
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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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+ * @inode: inode to board
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+ * @file: file handle to board
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+ *
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+ * The watchdog has a configurable API. There is a religious dispute
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+ * between people who want their watchdog to be able to shut down and
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+ * those who want to be sure if the watchdog manager dies the machine
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+ * reboots. In the former case we disable the counters, in the latter
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+ * case you have to open it again very soon.
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+ */
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+
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+static int wdog_release(struct inode *inode, struct file *file)
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+{
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+ if (expect_close == 42) {
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+ wdog_stop();
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+ } else {
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+ printk(KERN_CRIT
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+ "wdt: WDT device closed unexpectedly. WDT will not stop!\n");
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+ wdog_ping();
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+ }
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+ clear_bit(0, &wdog_is_open);
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+ expect_close = 0;
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+ return 0;
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+}
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+
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+/**
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+ * @this: our notifier block
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+ * @code: the event being reported
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+ * @unused: unused
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+ *
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+ * Our notifier is called on system shutdowns. Turn the watchdog
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+ * off so that it does not fire during the next reboot.
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+ */
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+
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+static int wdog_notify_sys(struct notifier_block *this, unsigned long code,
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+ void *unused)
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+{
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+ if (code == SYS_DOWN || code == SYS_HALT)
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+ wdog_stop();
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+ return NOTIFY_DONE;
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+}
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+
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+/*
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+ * Kernel Interfaces
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+ */
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+
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+
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+static const struct file_operations wdog_fops = {
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+ .owner = THIS_MODULE,
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+ .llseek = no_llseek,
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+ .write = wdog_write,
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+ .unlocked_ioctl = wdog_ioctl,
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+ .open = wdog_open,
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+ .release = wdog_release,
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+};
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+
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+static struct miscdevice wdog_miscdev = {
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+ .minor = WATCHDOG_MINOR,
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+ .name = "watchdog",
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+ .fops = &wdog_fops,
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+};
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+
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+/*
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+ * The WDT card needs to learn about soft shutdowns in order to
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+ * turn the timebomb registers off.
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+ */
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+
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+static struct notifier_block wdog_notifier = {
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+ .notifier_call = wdog_notify_sys,
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+};
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+
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+/**
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+ * cleanup_module:
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+ *
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+ * Unload the watchdog. You cannot do this with any file handles open.
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+ * If your watchdog is set to continue ticking on close and you unload
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+ * it, well it keeps ticking. We won't get the interrupt but the board
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+ * will not touch PC memory so all is fine. You just have to load a new
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+ * module in 60 seconds or reboot.
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+ */
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+
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+static void __exit wdog_exit(void)
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+{
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+ misc_deregister(&wdog_miscdev);
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+ unregister_reboot_notifier(&wdog_notifier);
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+}
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+
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+static int __init wdog_init(void)
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+{
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+ int ret;
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+
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+ /* Check that the heartbeat value is within it's range;
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+ if not reset to the default */
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+ if (wdog_set_heartbeat(heartbeat)) {
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+ wdog_set_heartbeat(WD_TIMO);
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+ printk(KERN_INFO "bcm2708_wdog: heartbeat value must be "
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+ "0 < heartbeat < %d, using %d\n",
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+ WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
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+ WD_TIMO);
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+ }
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+
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+ ret = register_reboot_notifier(&wdog_notifier);
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+ if (ret) {
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+ printk(KERN_ERR
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+ "wdt: cannot register reboot notifier (err=%d)\n", ret);
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+ goto out_reboot;
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+ }
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+
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+ ret = misc_register(&wdog_miscdev);
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+ if (ret) {
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+ printk(KERN_ERR
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+ "wdt: cannot register miscdev on minor=%d (err=%d)\n",
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+ WATCHDOG_MINOR, ret);
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+ goto out_misc;
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+ }
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+
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+ printk(KERN_INFO "bcm2708 watchdog, heartbeat=%d sec (nowayout=%d)\n",
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+ heartbeat, nowayout);
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+ return 0;
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+
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+out_misc:
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+ unregister_reboot_notifier(&wdog_notifier);
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+out_reboot:
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+ return ret;
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+}
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+
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+module_init(wdog_init);
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+module_exit(wdog_exit);
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+
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+MODULE_AUTHOR("Luke Diamand");
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+MODULE_DESCRIPTION("Driver for BCM2708 watchdog");
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+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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+MODULE_ALIAS_MISCDEV(TEMP_MINOR);
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+MODULE_LICENSE("GPL");
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+
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--
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1.9.1
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