Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1068 insertions, 0 deletions

diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
new file mode 100644
index 000000000000..fd7093879c66
--- /dev/null
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -0,0 +1,1068 @@
+/*
+ * ipmi_watchdog.c
+ *
+ * A watchdog timer based upon the IPMI interface.
+ *
+ * Author: MontaVista Software, Inc.
+ *         Corey Minyard <minyard@mvista.com>
+ *         source@mvista.com
+ *
+ * Copyright 2002 MontaVista Software Inc.
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *
+ *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ *  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ *  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ *  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+ *  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+ *  USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/ipmi.h>
+#include <linux/ipmi_smi.h>
+#include <linux/watchdog.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/rwsem.h>
+#include <linux/errno.h>
+#include <asm/uaccess.h>
+#include <linux/notifier.h>
+#include <linux/nmi.h>
+#include <linux/reboot.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#ifdef CONFIG_X86_LOCAL_APIC
+#include <asm/apic.h>
+#endif
+
+#define	PFX "IPMI Watchdog: "
+
+#define IPMI_WATCHDOG_VERSION "v33"
+
+/*
+ * The IPMI command/response information for the watchdog timer.
+ */
+
+/* values for byte 1 of the set command, byte 2 of the get response. */
+#define WDOG_DONT_LOG		(1 << 7)
+#define WDOG_DONT_STOP_ON_SET	(1 << 6)
+#define WDOG_SET_TIMER_USE(byte, use) \
+	byte = ((byte) & 0xf8) | ((use) & 0x7)
+#define WDOG_GET_TIMER_USE(byte) ((byte) & 0x7)
+#define WDOG_TIMER_USE_BIOS_FRB2	1
+#define WDOG_TIMER_USE_BIOS_POST	2
+#define WDOG_TIMER_USE_OS_LOAD		3
+#define WDOG_TIMER_USE_SMS_OS		4
+#define WDOG_TIMER_USE_OEM		5
+
+/* values for byte 2 of the set command, byte 3 of the get response. */
+#define WDOG_SET_PRETIMEOUT_ACT(byte, use) \
+	byte = ((byte) & 0x8f) | (((use) & 0x7) << 4)
+#define WDOG_GET_PRETIMEOUT_ACT(byte) (((byte) >> 4) & 0x7)
+#define WDOG_PRETIMEOUT_NONE		0
+#define WDOG_PRETIMEOUT_SMI		1
+#define WDOG_PRETIMEOUT_NMI		2
+#define WDOG_PRETIMEOUT_MSG_INT		3
+
+/* Operations that can be performed on a pretimout. */
+#define WDOG_PREOP_NONE		0
+#define WDOG_PREOP_PANIC	1
+#define WDOG_PREOP_GIVE_DATA	2 /* Cause data to be available to
+                                     read.  Doesn't work in NMI
+                                     mode. */
+
+/* Actions to perform on a full timeout. */
+#define WDOG_SET_TIMEOUT_ACT(byte, use) \
+	byte = ((byte) & 0xf8) | ((use) & 0x7)
+#define WDOG_GET_TIMEOUT_ACT(byte) ((byte) & 0x7)
+#define WDOG_TIMEOUT_NONE		0
+#define WDOG_TIMEOUT_RESET		1
+#define WDOG_TIMEOUT_POWER_DOWN		2
+#define WDOG_TIMEOUT_POWER_CYCLE	3
+
+/* Byte 3 of the get command, byte 4 of the get response is the
+   pre-timeout in seconds. */
+
+/* Bits for setting byte 4 of the set command, byte 5 of the get response. */
+#define WDOG_EXPIRE_CLEAR_BIOS_FRB2	(1 << 1)
+#define WDOG_EXPIRE_CLEAR_BIOS_POST	(1 << 2)
+#define WDOG_EXPIRE_CLEAR_OS_LOAD	(1 << 3)
+#define WDOG_EXPIRE_CLEAR_SMS_OS	(1 << 4)
+#define WDOG_EXPIRE_CLEAR_OEM		(1 << 5)
+
+/* Setting/getting the watchdog timer value.  This is for bytes 5 and
+   6 (the timeout time) of the set command, and bytes 6 and 7 (the
+   timeout time) and 8 and 9 (the current countdown value) of the
+   response.  The timeout value is given in seconds (in the command it
+   is 100ms intervals). */
+#define WDOG_SET_TIMEOUT(byte1, byte2, val) \
+	(byte1) = (((val) * 10) & 0xff), (byte2) = (((val) * 10) >> 8)
+#define WDOG_GET_TIMEOUT(byte1, byte2) \
+	(((byte1) | ((byte2) << 8)) / 10)
+
+#define IPMI_WDOG_RESET_TIMER		0x22
+#define IPMI_WDOG_SET_TIMER		0x24
+#define IPMI_WDOG_GET_TIMER		0x25
+
+/* These are here until the real ones get into the watchdog.h interface. */
+#ifndef WDIOC_GETTIMEOUT
+#define	WDIOC_GETTIMEOUT        _IOW(WATCHDOG_IOCTL_BASE, 20, int)
+#endif
+#ifndef WDIOC_SET_PRETIMEOUT
+#define	WDIOC_SET_PRETIMEOUT     _IOW(WATCHDOG_IOCTL_BASE, 21, int)
+#endif
+#ifndef WDIOC_GET_PRETIMEOUT
+#define	WDIOC_GET_PRETIMEOUT     _IOW(WATCHDOG_IOCTL_BASE, 22, int)
+#endif
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+static int nowayout = 1;
+#else
+static int nowayout;
+#endif
+
+static ipmi_user_t watchdog_user = NULL;
+
+/* Default the timeout to 10 seconds. */
+static int timeout = 10;
+
+/* The pre-timeout is disabled by default. */
+static int pretimeout = 0;
+
+/* Default action is to reset the board on a timeout. */
+static unsigned char action_val = WDOG_TIMEOUT_RESET;
+
+static char action[16] = "reset";
+
+static unsigned char preaction_val = WDOG_PRETIMEOUT_NONE;
+
+static char preaction[16] = "pre_none";
+
+static unsigned char preop_val = WDOG_PREOP_NONE;
+
+static char preop[16] = "preop_none";
+static DEFINE_SPINLOCK(ipmi_read_lock);
+static char data_to_read = 0;
+static DECLARE_WAIT_QUEUE_HEAD(read_q);
+static struct fasync_struct *fasync_q = NULL;
+static char pretimeout_since_last_heartbeat = 0;
+static char expect_close;
+
+/* If true, the driver will start running as soon as it is configured
+   and ready. */
+static int start_now = 0;
+
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Timeout value in seconds.");
+module_param(pretimeout, int, 0);
+MODULE_PARM_DESC(pretimeout, "Pretimeout value in seconds.");
+module_param_string(action, action, sizeof(action), 0);
+MODULE_PARM_DESC(action, "Timeout action. One of: "
+		 "reset, none, power_cycle, power_off.");
+module_param_string(preaction, preaction, sizeof(preaction), 0);
+MODULE_PARM_DESC(preaction, "Pretimeout action.  One of: "
+		 "pre_none, pre_smi, pre_nmi, pre_int.");
+module_param_string(preop, preop, sizeof(preop), 0);
+MODULE_PARM_DESC(preop, "Pretimeout driver operation.  One of: "
+		 "preop_none, preop_panic, preop_give_data.");
+module_param(start_now, int, 0);
+MODULE_PARM_DESC(start_now, "Set to 1 to start the watchdog as"
+		 "soon as the driver is loaded.");
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
+
+/* Default state of the timer. */
+static unsigned char ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
+
+/* If shutting down via IPMI, we ignore the heartbeat. */
+static int ipmi_ignore_heartbeat = 0;
+
+/* Is someone using the watchdog?  Only one user is allowed. */
+static unsigned long ipmi_wdog_open = 0;
+
+/* If set to 1, the heartbeat command will set the state to reset and
+   start the timer.  The timer doesn't normally run when the driver is
+   first opened until the heartbeat is set the first time, this
+   variable is used to accomplish this. */
+static int ipmi_start_timer_on_heartbeat = 0;
+
+/* IPMI version of the BMC. */
+static unsigned char ipmi_version_major;
+static unsigned char ipmi_version_minor;
+
+
+static int ipmi_heartbeat(void);
+static void panic_halt_ipmi_heartbeat(void);
+
+
+/* We use a semaphore to make sure that only one thing can send a set
+   timeout at one time, because we only have one copy of the data.
+   The semaphore is claimed when the set_timeout is sent and freed
+   when both messages are free. */
+static atomic_t set_timeout_tofree = ATOMIC_INIT(0);
+static DECLARE_MUTEX(set_timeout_lock);
+static void set_timeout_free_smi(struct ipmi_smi_msg *msg)
+{
+    if (atomic_dec_and_test(&set_timeout_tofree))
+	    up(&set_timeout_lock);
+}
+static void set_timeout_free_recv(struct ipmi_recv_msg *msg)
+{
+    if (atomic_dec_and_test(&set_timeout_tofree))
+	    up(&set_timeout_lock);
+}
+static struct ipmi_smi_msg set_timeout_smi_msg =
+{
+	.done = set_timeout_free_smi
+};
+static struct ipmi_recv_msg set_timeout_recv_msg =
+{
+	.done = set_timeout_free_recv
+};
+ 
+static int i_ipmi_set_timeout(struct ipmi_smi_msg  *smi_msg,
+			      struct ipmi_recv_msg *recv_msg,
+			      int                  *send_heartbeat_now)
+{
+	struct kernel_ipmi_msg            msg;
+	unsigned char                     data[6];
+	int                               rv;
+	struct ipmi_system_interface_addr addr;
+	int                               hbnow = 0;
+
+
+	data[0] = 0;
+	WDOG_SET_TIMER_USE(data[0], WDOG_TIMER_USE_SMS_OS);
+
+	if ((ipmi_version_major > 1)
+	    || ((ipmi_version_major == 1) && (ipmi_version_minor >= 5)))
+	{
+		/* This is an IPMI 1.5-only feature. */
+		data[0] |= WDOG_DONT_STOP_ON_SET;
+	} else if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
+		/* In ipmi 1.0, setting the timer stops the watchdog, we
+		   need to start it back up again. */
+		hbnow = 1;
+	}
+
+	data[1] = 0;
+	WDOG_SET_TIMEOUT_ACT(data[1], ipmi_watchdog_state);
+	if (pretimeout > 0) {
+	    WDOG_SET_PRETIMEOUT_ACT(data[1], preaction_val);
+	    data[2] = pretimeout;
+	} else {
+	    WDOG_SET_PRETIMEOUT_ACT(data[1], WDOG_PRETIMEOUT_NONE);
+	    data[2] = 0; /* No pretimeout. */
+	}
+	data[3] = 0;
+	WDOG_SET_TIMEOUT(data[4], data[5], timeout);
+
+	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+	addr.channel = IPMI_BMC_CHANNEL;
+	addr.lun = 0;
+
+	msg.netfn = 0x06;
+	msg.cmd = IPMI_WDOG_SET_TIMER;
+	msg.data = data;
+	msg.data_len = sizeof(data);
+	rv = ipmi_request_supply_msgs(watchdog_user,
+				      (struct ipmi_addr *) &addr,
+				      0,
+				      &msg,
+				      NULL,
+				      smi_msg,
+				      recv_msg,
+				      1);
+	if (rv) {
+		printk(KERN_WARNING PFX "set timeout error: %d\n",
+		       rv);
+	}
+
+	if (send_heartbeat_now)
+	    *send_heartbeat_now = hbnow;
+
+	return rv;
+}
+
+/* Parameters to ipmi_set_timeout */
+#define IPMI_SET_TIMEOUT_NO_HB			0
+#define IPMI_SET_TIMEOUT_HB_IF_NECESSARY	1
+#define IPMI_SET_TIMEOUT_FORCE_HB		2
+
+static int ipmi_set_timeout(int do_heartbeat)
+{
+	int send_heartbeat_now;
+	int rv;
+
+
+	/* We can only send one of these at a time. */
+	down(&set_timeout_lock);
+
+	atomic_set(&set_timeout_tofree, 2);
+
+	rv = i_ipmi_set_timeout(&set_timeout_smi_msg,
+				&set_timeout_recv_msg,
+				&send_heartbeat_now);
+	if (rv) {
+		up(&set_timeout_lock);
+	} else {
+		if ((do_heartbeat == IPMI_SET_TIMEOUT_FORCE_HB)
+		    || ((send_heartbeat_now)
+			&& (do_heartbeat == IPMI_SET_TIMEOUT_HB_IF_NECESSARY)))
+		{
+			rv = ipmi_heartbeat();
+		}
+	}
+
+	return rv;
+}
+
+static void dummy_smi_free(struct ipmi_smi_msg *msg)
+{
+}
+static void dummy_recv_free(struct ipmi_recv_msg *msg)
+{
+}
+static struct ipmi_smi_msg panic_halt_smi_msg =
+{
+	.done = dummy_smi_free
+};
+static struct ipmi_recv_msg panic_halt_recv_msg =
+{
+	.done = dummy_recv_free
+};
+
+/* Special call, doesn't claim any locks.  This is only to be called
+   at panic or halt time, in run-to-completion mode, when the caller
+   is the only CPU and the only thing that will be going is these IPMI
+   calls. */
+static void panic_halt_ipmi_set_timeout(void)
+{
+	int send_heartbeat_now;
+	int rv;
+
+	rv = i_ipmi_set_timeout(&panic_halt_smi_msg,
+				&panic_halt_recv_msg,
+				&send_heartbeat_now);
+	if (!rv) {
+		if (send_heartbeat_now)
+			panic_halt_ipmi_heartbeat();
+	}
+}
+
+/* We use a semaphore to make sure that only one thing can send a
+   heartbeat at one time, because we only have one copy of the data.
+   The semaphore is claimed when the set_timeout is sent and freed
+   when both messages are free. */
+static atomic_t heartbeat_tofree = ATOMIC_INIT(0);
+static DECLARE_MUTEX(heartbeat_lock);
+static DECLARE_MUTEX_LOCKED(heartbeat_wait_lock);
+static void heartbeat_free_smi(struct ipmi_smi_msg *msg)
+{
+    if (atomic_dec_and_test(&heartbeat_tofree))
+	    up(&heartbeat_wait_lock);
+}
+static void heartbeat_free_recv(struct ipmi_recv_msg *msg)
+{
+    if (atomic_dec_and_test(&heartbeat_tofree))
+	    up(&heartbeat_wait_lock);
+}
+static struct ipmi_smi_msg heartbeat_smi_msg =
+{
+	.done = heartbeat_free_smi
+};
+static struct ipmi_recv_msg heartbeat_recv_msg =
+{
+	.done = heartbeat_free_recv
+};
+ 
+static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg =
+{
+	.done = dummy_smi_free
+};
+static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg =
+{
+	.done = dummy_recv_free
+};
+ 
+static int ipmi_heartbeat(void)
+{
+	struct kernel_ipmi_msg            msg;
+	int                               rv;
+	struct ipmi_system_interface_addr addr;
+
+	if (ipmi_ignore_heartbeat) {
+		return 0;
+	}
+
+	if (ipmi_start_timer_on_heartbeat) {
+		ipmi_start_timer_on_heartbeat = 0;
+		ipmi_watchdog_state = action_val;
+		return ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
+	} else if (pretimeout_since_last_heartbeat) {
+		/* A pretimeout occurred, make sure we set the timeout.
+		   We don't want to set the action, though, we want to
+		   leave that alone (thus it can't be combined with the
+		   above operation. */
+		pretimeout_since_last_heartbeat = 0;
+		return ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
+	}
+
+	down(&heartbeat_lock);
+
+	atomic_set(&heartbeat_tofree, 2);
+
+	/* Don't reset the timer if we have the timer turned off, that
+           re-enables the watchdog. */
+	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE) {
+		up(&heartbeat_lock);
+		return 0;
+	}
+
+	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+	addr.channel = IPMI_BMC_CHANNEL;
+	addr.lun = 0;
+
+	msg.netfn = 0x06;
+	msg.cmd = IPMI_WDOG_RESET_TIMER;
+	msg.data = NULL;
+	msg.data_len = 0;
+	rv = ipmi_request_supply_msgs(watchdog_user,
+				      (struct ipmi_addr *) &addr,
+				      0,
+				      &msg,
+				      NULL,
+				      &heartbeat_smi_msg,
+				      &heartbeat_recv_msg,
+				      1);
+	if (rv) {
+		up(&heartbeat_lock);
+		printk(KERN_WARNING PFX "heartbeat failure: %d\n",
+		       rv);
+		return rv;
+	}
+
+	/* Wait for the heartbeat to be sent. */
+	down(&heartbeat_wait_lock);
+
+	if (heartbeat_recv_msg.msg.data[0] != 0) {
+	    /* Got an error in the heartbeat response.  It was already
+	       reported in ipmi_wdog_msg_handler, but we should return
+	       an error here. */
+	    rv = -EINVAL;
+	}
+
+	up(&heartbeat_lock);
+
+	return rv;
+}
+
+static void panic_halt_ipmi_heartbeat(void)
+{
+	struct kernel_ipmi_msg             msg;
+	struct ipmi_system_interface_addr addr;
+
+
+	/* Don't reset the timer if we have the timer turned off, that
+           re-enables the watchdog. */
+	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
+		return;
+
+	addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+	addr.channel = IPMI_BMC_CHANNEL;
+	addr.lun = 0;
+
+	msg.netfn = 0x06;
+	msg.cmd = IPMI_WDOG_RESET_TIMER;
+	msg.data = NULL;
+	msg.data_len = 0;
+	ipmi_request_supply_msgs(watchdog_user,
+				 (struct ipmi_addr *) &addr,
+				 0,
+				 &msg,
+				 NULL,
+				 &panic_halt_heartbeat_smi_msg,
+				 &panic_halt_heartbeat_recv_msg,
+				 1);
+}
+
+static struct watchdog_info ident=
+{
+	.options	= 0,	/* WDIOF_SETTIMEOUT, */
+	.firmware_version = 1,
+	.identity	= "IPMI"
+};
+
+static int ipmi_ioctl(struct inode *inode, struct file *file,
+		      unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int i;
+	int val;
+
+	switch(cmd) {
+	case WDIOC_GETSUPPORT:
+		i = copy_to_user(argp, &ident, sizeof(ident));
+		return i ? -EFAULT : 0;
+
+	case WDIOC_SETTIMEOUT:
+		i = copy_from_user(&val, argp, sizeof(int));
+		if (i)
+			return -EFAULT;
+		timeout = val;
+		return ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
+
+	case WDIOC_GETTIMEOUT:
+		i = copy_to_user(argp, &timeout, sizeof(timeout));
+		if (i)
+			return -EFAULT;
+		return 0;
+
+	case WDIOC_SET_PRETIMEOUT:
+		i = copy_from_user(&val, argp, sizeof(int));
+		if (i)
+			return -EFAULT;
+		pretimeout = val;
+		return ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
+
+	case WDIOC_GET_PRETIMEOUT:
+		i = copy_to_user(argp, &pretimeout, sizeof(pretimeout));
+		if (i)
+			return -EFAULT;
+		return 0;
+
+	case WDIOC_KEEPALIVE:
+		return ipmi_heartbeat();
+
+	case WDIOC_SETOPTIONS:
+		i = copy_from_user(&val, argp, sizeof(int));
+		if (i)
+			return -EFAULT;
+		if (val & WDIOS_DISABLECARD)
+		{
+			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
+			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
+			ipmi_start_timer_on_heartbeat = 0;
+		}
+
+		if (val & WDIOS_ENABLECARD)
+		{
+			ipmi_watchdog_state = action_val;
+			ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
+		}
+		return 0;
+
+	case WDIOC_GETSTATUS:
+		val = 0;
+		i = copy_to_user(argp, &val, sizeof(val));
+		if (i)
+			return -EFAULT;
+		return 0;
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
+static ssize_t ipmi_write(struct file *file,
+			  const char  __user *buf,
+			  size_t      len,
+			  loff_t      *ppos)
+{
+	int rv;
+
+	if (len) {
+	    	if (!nowayout) {
+		    	size_t i;
+
+			/* In case it was set long ago */
+			expect_close = 0;
+
+    			for (i = 0; i != len; i++) {
+				char c;
+
+				if (get_user(c, buf + i))
+					return -EFAULT;
+				if (c == 'V')
+					expect_close = 42;
+			}
+		}
+		rv = ipmi_heartbeat();
+		if (rv)
+			return rv;
+		return 1;
+	}
+	return 0;
+}
+
+static ssize_t ipmi_read(struct file *file,
+			 char        __user *buf,
+			 size_t      count,
+			 loff_t      *ppos)
+{
+	int          rv = 0;
+	wait_queue_t wait;
+
+	if (count <= 0)
+		return 0;
+
+	/* Reading returns if the pretimeout has gone off, and it only does
+	   it once per pretimeout. */
+	spin_lock(&ipmi_read_lock);
+	if (!data_to_read) {
+		if (file->f_flags & O_NONBLOCK) {
+			rv = -EAGAIN;
+			goto out;
+		}
+		
+		init_waitqueue_entry(&wait, current);
+		add_wait_queue(&read_q, &wait);
+		while (!data_to_read) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			spin_unlock(&ipmi_read_lock);
+			schedule();
+			spin_lock(&ipmi_read_lock);
+		}
+		remove_wait_queue(&read_q, &wait);
+	    
+		if (signal_pending(current)) {
+			rv = -ERESTARTSYS;
+			goto out;
+		}
+	}
+	data_to_read = 0;
+
+ out:
+	spin_unlock(&ipmi_read_lock);
+
+	if (rv == 0) {
+		if (copy_to_user(buf, &data_to_read, 1))
+			rv = -EFAULT;
+		else
+			rv = 1;
+	}
+
+	return rv;
+}
+
+static int ipmi_open(struct inode *ino, struct file *filep)
+{
+        switch (iminor(ino))
+        {
+                case WATCHDOG_MINOR:
+		    if(test_and_set_bit(0, &ipmi_wdog_open))
+                        return -EBUSY;
+
+		    /* Don't start the timer now, let it start on the
+		       first heartbeat. */
+		    ipmi_start_timer_on_heartbeat = 1;
+                    return nonseekable_open(ino, filep);
+
+                default:
+                    return (-ENODEV);
+        }
+}
+
+static unsigned int ipmi_poll(struct file *file, poll_table *wait)
+{
+	unsigned int mask = 0;
+	
+	poll_wait(file, &read_q, wait);
+
+	spin_lock(&ipmi_read_lock);
+	if (data_to_read)
+		mask |= (POLLIN | POLLRDNORM);
+	spin_unlock(&ipmi_read_lock);
+
+	return mask;
+}
+
+static int ipmi_fasync(int fd, struct file *file, int on)
+{
+	int result;
+
+	result = fasync_helper(fd, file, on, &fasync_q);
+
+	return (result);
+}
+
+static int ipmi_close(struct inode *ino, struct file *filep)
+{
+	if (iminor(ino)==WATCHDOG_MINOR)
+	{
+		if (expect_close == 42) {
+			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
+			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
+			clear_bit(0, &ipmi_wdog_open);
+		} else {
+			printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
+			ipmi_heartbeat();
+		}
+	}
+
+	ipmi_fasync (-1, filep, 0);
+	expect_close = 0;
+
+	return 0;
+}
+
+static struct file_operations ipmi_wdog_fops = {
+	.owner   = THIS_MODULE,
+	.read    = ipmi_read,
+	.poll    = ipmi_poll,
+	.write   = ipmi_write,
+	.ioctl   = ipmi_ioctl,
+	.open    = ipmi_open,
+	.release = ipmi_close,
+	.fasync  = ipmi_fasync,
+};
+
+static struct miscdevice ipmi_wdog_miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= "watchdog",
+	.fops		= &ipmi_wdog_fops
+};
+
+static DECLARE_RWSEM(register_sem);
+
+static void ipmi_wdog_msg_handler(struct ipmi_recv_msg *msg,
+				  void                 *handler_data)
+{
+	if (msg->msg.data[0] != 0) {
+		printk(KERN_ERR PFX "response: Error %x on cmd %x\n",
+		       msg->msg.data[0],
+		       msg->msg.cmd);
+	}
+	
+	ipmi_free_recv_msg(msg);
+}
+
+static void ipmi_wdog_pretimeout_handler(void *handler_data)
+{
+	if (preaction_val != WDOG_PRETIMEOUT_NONE) {
+		if (preop_val == WDOG_PREOP_PANIC)
+			panic("Watchdog pre-timeout");
+		else if (preop_val == WDOG_PREOP_GIVE_DATA) {
+			spin_lock(&ipmi_read_lock);
+			data_to_read = 1;
+			wake_up_interruptible(&read_q);
+			kill_fasync(&fasync_q, SIGIO, POLL_IN);
+
+			spin_unlock(&ipmi_read_lock);
+		}
+	}
+
+	/* On some machines, the heartbeat will give
+	   an error and not work unless we re-enable
+	   the timer.   So do so. */
+	pretimeout_since_last_heartbeat = 1;
+}
+
+static struct ipmi_user_hndl ipmi_hndlrs =
+{
+	.ipmi_recv_hndl           = ipmi_wdog_msg_handler,
+	.ipmi_watchdog_pretimeout = ipmi_wdog_pretimeout_handler
+};
+
+static void ipmi_register_watchdog(int ipmi_intf)
+{
+	int rv = -EBUSY;
+
+	down_write(&register_sem);
+	if (watchdog_user)
+		goto out;
+
+	rv = ipmi_create_user(ipmi_intf, &ipmi_hndlrs, NULL, &watchdog_user);
+	if (rv < 0) {
+		printk(KERN_CRIT PFX "Unable to register with ipmi\n");
+		goto out;
+	}
+
+	ipmi_get_version(watchdog_user,
+			 &ipmi_version_major,
+			 &ipmi_version_minor);
+
+	rv = misc_register(&ipmi_wdog_miscdev);
+	if (rv < 0) {
+		ipmi_destroy_user(watchdog_user);
+		watchdog_user = NULL;
+		printk(KERN_CRIT PFX "Unable to register misc device\n");
+	}
+
+ out:
+	up_write(&register_sem);
+
+	if ((start_now) && (rv == 0)) {
+		/* Run from startup, so start the timer now. */
+		start_now = 0; /* Disable this function after first startup. */
+		ipmi_watchdog_state = action_val;
+		ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
+		printk(KERN_INFO PFX "Starting now!\n");
+	}
+}
+
+#ifdef HAVE_NMI_HANDLER
+static int
+ipmi_nmi(void *dev_id, struct pt_regs *regs, int cpu, int handled)
+{
+	/* If no one else handled the NMI, we assume it was the IPMI
+           watchdog. */
+	if ((!handled) && (preop_val == WDOG_PREOP_PANIC))
+		panic(PFX "pre-timeout");
+
+	/* On some machines, the heartbeat will give
+	   an error and not work unless we re-enable
+	   the timer.   So do so. */
+	pretimeout_since_last_heartbeat = 1;
+
+	return NOTIFY_DONE;
+}
+
+static struct nmi_handler ipmi_nmi_handler =
+{
+	.link     = LIST_HEAD_INIT(ipmi_nmi_handler.link),
+	.dev_name = "ipmi_watchdog",
+	.dev_id   = NULL,
+	.handler  = ipmi_nmi,
+	.priority = 0, /* Call us last. */
+};
+#endif
+
+static int wdog_reboot_handler(struct notifier_block *this,
+			       unsigned long         code,
+			       void                  *unused)
+{
+	static int reboot_event_handled = 0;
+
+	if ((watchdog_user) && (!reboot_event_handled)) {
+		/* Make sure we only do this once. */
+		reboot_event_handled = 1;
+
+		if (code == SYS_DOWN || code == SYS_HALT) {
+			/* Disable the WDT if we are shutting down. */
+			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
+			panic_halt_ipmi_set_timeout();
+		} else {
+			/* Set a long timer to let the reboot happens, but
+			   reboot if it hangs. */
+			timeout = 120;
+			pretimeout = 0;
+			ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
+			panic_halt_ipmi_set_timeout();
+		}
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block wdog_reboot_notifier = {
+	.notifier_call	= wdog_reboot_handler,
+	.next		= NULL,
+	.priority	= 0
+};
+
+static int wdog_panic_handler(struct notifier_block *this,
+			      unsigned long         event,
+			      void                  *unused)
+{
+	static int panic_event_handled = 0;
+
+	/* On a panic, if we have a panic timeout, make sure that the thing
+	   reboots, even if it hangs during that panic. */
+	if (watchdog_user && !panic_event_handled) {
+		/* Make sure the panic doesn't hang, and make sure we
+		   do this only once. */
+		panic_event_handled = 1;
+	    
+		timeout = 255;
+		pretimeout = 0;
+		ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
+		panic_halt_ipmi_set_timeout();
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block wdog_panic_notifier = {
+	.notifier_call	= wdog_panic_handler,
+	.next		= NULL,
+	.priority	= 150	/* priority: INT_MAX >= x >= 0 */
+};
+
+
+static void ipmi_new_smi(int if_num)
+{
+	ipmi_register_watchdog(if_num);
+}
+
+static void ipmi_smi_gone(int if_num)
+{
+	/* This can never be called, because once the watchdog is
+	   registered, the interface can't go away until the watchdog
+	   is unregistered. */
+}
+
+static struct ipmi_smi_watcher smi_watcher =
+{
+	.owner    = THIS_MODULE,
+	.new_smi  = ipmi_new_smi,
+	.smi_gone = ipmi_smi_gone
+};
+
+static int __init ipmi_wdog_init(void)
+{
+	int rv;
+
+	printk(KERN_INFO PFX "driver version "
+	       IPMI_WATCHDOG_VERSION "\n");
+
+	if (strcmp(action, "reset") == 0) {
+		action_val = WDOG_TIMEOUT_RESET;
+	} else if (strcmp(action, "none") == 0) {
+		action_val = WDOG_TIMEOUT_NONE;
+	} else if (strcmp(action, "power_cycle") == 0) {
+		action_val = WDOG_TIMEOUT_POWER_CYCLE;
+	} else if (strcmp(action, "power_off") == 0) {
+		action_val = WDOG_TIMEOUT_POWER_DOWN;
+	} else {
+		action_val = WDOG_TIMEOUT_RESET;
+		printk(KERN_INFO PFX "Unknown action '%s', defaulting to"
+		       " reset\n", action);
+	}
+
+	if (strcmp(preaction, "pre_none") == 0) {
+		preaction_val = WDOG_PRETIMEOUT_NONE;
+	} else if (strcmp(preaction, "pre_smi") == 0) {
+		preaction_val = WDOG_PRETIMEOUT_SMI;
+#ifdef HAVE_NMI_HANDLER
+	} else if (strcmp(preaction, "pre_nmi") == 0) {
+		preaction_val = WDOG_PRETIMEOUT_NMI;
+#endif
+	} else if (strcmp(preaction, "pre_int") == 0) {
+		preaction_val = WDOG_PRETIMEOUT_MSG_INT;
+	} else {
+		preaction_val = WDOG_PRETIMEOUT_NONE;
+		printk(KERN_INFO PFX "Unknown preaction '%s', defaulting to"
+		       " none\n", preaction);
+	}
+
+	if (strcmp(preop, "preop_none") == 0) {
+		preop_val = WDOG_PREOP_NONE;
+	} else if (strcmp(preop, "preop_panic") == 0) {
+		preop_val = WDOG_PREOP_PANIC;
+	} else if (strcmp(preop, "preop_give_data") == 0) {
+		preop_val = WDOG_PREOP_GIVE_DATA;
+	} else {
+		preop_val = WDOG_PREOP_NONE;
+		printk(KERN_INFO PFX "Unknown preop '%s', defaulting to"
+		       " none\n", preop);
+	}
+
+#ifdef HAVE_NMI_HANDLER
+	if (preaction_val == WDOG_PRETIMEOUT_NMI) {
+		if (preop_val == WDOG_PREOP_GIVE_DATA) {
+			printk(KERN_WARNING PFX "Pretimeout op is to give data"
+			       " but NMI pretimeout is enabled, setting"
+			       " pretimeout op to none\n");
+			preop_val = WDOG_PREOP_NONE;
+		}
+#ifdef CONFIG_X86_LOCAL_APIC
+		if (nmi_watchdog == NMI_IO_APIC) {
+			printk(KERN_WARNING PFX "nmi_watchdog is set to IO APIC"
+			       " mode (value is %d), that is incompatible"
+			       " with using NMI in the IPMI watchdog."
+			       " Disabling IPMI nmi pretimeout.\n",
+			       nmi_watchdog);
+			preaction_val = WDOG_PRETIMEOUT_NONE;
+		} else {
+#endif
+		rv = request_nmi(&ipmi_nmi_handler);
+		if (rv) {
+			printk(KERN_WARNING PFX "Can't register nmi handler\n");
+			return rv;
+		}
+#ifdef CONFIG_X86_LOCAL_APIC
+		}
+#endif
+	}
+#endif
+
+	rv = ipmi_smi_watcher_register(&smi_watcher);
+	if (rv) {
+#ifdef HAVE_NMI_HANDLER
+		if (preaction_val == WDOG_PRETIMEOUT_NMI)
+			release_nmi(&ipmi_nmi_handler);
+#endif
+		printk(KERN_WARNING PFX "can't register smi watcher\n");
+		return rv;
+	}
+
+	register_reboot_notifier(&wdog_reboot_notifier);
+	notifier_chain_register(&panic_notifier_list, &wdog_panic_notifier);
+
+	return 0;
+}
+
+static __exit void ipmi_unregister_watchdog(void)
+{
+	int rv;
+
+	down_write(&register_sem);
+
+#ifdef HAVE_NMI_HANDLER
+	if (preaction_val == WDOG_PRETIMEOUT_NMI)
+		release_nmi(&ipmi_nmi_handler);
+#endif
+
+	notifier_chain_unregister(&panic_notifier_list, &wdog_panic_notifier);
+	unregister_reboot_notifier(&wdog_reboot_notifier);
+
+	if (! watchdog_user)
+		goto out;
+
+	/* Make sure no one can call us any more. */
+	misc_deregister(&ipmi_wdog_miscdev);
+
+	/* Wait to make sure the message makes it out.  The lower layer has
+	   pointers to our buffers, we want to make sure they are done before
+	   we release our memory. */
+	while (atomic_read(&set_timeout_tofree)) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule_timeout(1);
+	}
+
+	/* Disconnect from IPMI. */
+	rv = ipmi_destroy_user(watchdog_user);
+	if (rv) {
+		printk(KERN_WARNING PFX "error unlinking from IPMI: %d\n",
+		       rv);
+	}
+	watchdog_user = NULL;
+
+ out:
+	up_write(&register_sem);
+}
+
+static void __exit ipmi_wdog_exit(void)
+{
+	ipmi_smi_watcher_unregister(&smi_watcher);
+	ipmi_unregister_watchdog();
+}
+module_exit(ipmi_wdog_exit);
+module_init(ipmi_wdog_init);
+MODULE_LICENSE("GPL");