text: // SPDX-License-Identifier: GPL-2.0+
  /*
   * 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.
   */
  
  #define pr_fmt(fmt) "IPMI Watchdog: " fmt
  
  #include <linux/module.h>
  #include <linux/moduleparam.h>
  #include <linux/ipmi.h>
  #include <linux/ipmi_smi.h>
  #include <linux/mutex.h>
  #include <linux/watchdog.h>
  #include <linux/miscdevice.h>
  #include <linux/init.h>
  #include <linux/completion.h>
  #include <linux/kdebug.h>
  #include <linux/rwsem.h>
  #include <linux/errno.h>
  #include <linux/uaccess.h>
  #include <linux/notifier.h>
  #include <linux/nmi.h>
  #include <linux/reboot.h>
  #include <linux/wait.h>
  #include <linux/poll.h>
  #include <linux/string.h>
  #include <linux/ctype.h>
  #include <linux/delay.h>
  #include <linux/atomic.h>
  #include <linux/sched/signal.h>
  
  #ifdef CONFIG_X86
  /*
   * This is ugly, but I've determined that x86 is the only architecture
   * that can reasonably support the IPMI NMI watchdog timeout at this
   * time.  If another architecture adds this capability somehow, it
   * will have to be a somewhat different mechanism and I have no idea
   * how it will work.  So in the unlikely event that another
   * architecture supports this, we can figure out a good generic
   * mechanism for it at that time.
   */
  #include <asm/kdebug.h>
  #include <asm/nmi.h>
  #define HAVE_DIE_NMI
  #endif
  
  /*
   * 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
  /* Cause data to be available to read.  Doesn't work in NMI mode. */
  #define WDOG_PREOP_GIVE_DATA	2
  
  /* 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
  
  #define IPMI_WDOG_TIMER_NOT_INIT_RESP	0x80
  
  static DEFINE_MUTEX(ipmi_watchdog_mutex);
  static bool nowayout = WATCHDOG_NOWAYOUT;
  
  static struct ipmi_user *watchdog_user;
  static int watchdog_ifnum;
  
  /* Default the timeout to 10 seconds. */
  static int timeout = 10;
  
  /* The pre-timeout is disabled by default. */
  static int pretimeout;
  
  /* Default timeout to set on panic */
  static int panic_wdt_timeout = 255;
  
  /* 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;
  static DECLARE_WAIT_QUEUE_HEAD(read_q);
  static struct fasync_struct *fasync_q;
  static atomic_t pretimeout_since_last_heartbeat;
  static char expect_close;
  
  static int ifnum_to_use = -1;
  
  /* 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);
  static void ipmi_register_watchdog(int ipmi_intf);
  static void ipmi_unregister_watchdog(int ipmi_intf);
  
  /*
   * If true, the driver will start running as soon as it is configured
   * and ready.
   */
  static int start_now;
  
  static int set_param_timeout(const char *val, const struct kernel_param *kp)
  {
  	char *endp;
  	int  l;
  	int  rv = 0;
  
  	if (!val)
  		return -EINVAL;
  	l = simple_strtoul(val, &endp, 0);
  	if (endp == val)
  		return -EINVAL;
  
  	*((int *)kp->arg) = l;
  	if (watchdog_user)
  		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
  
  	return rv;
  }
  
  static const struct kernel_param_ops param_ops_timeout = {
  	.set = set_param_timeout,
  	.get = param_get_int,
  };
  #define param_check_timeout param_check_int
  
  typedef int (*action_fn)(const char *intval, char *outval);
  
  static int action_op(const char *inval, char *outval);
  static int preaction_op(const char *inval, char *outval);
  static int preop_op(const char *inval, char *outval);
  static void check_parms(void);
  
  static int set_param_str(const char *val, const struct kernel_param *kp)
  {
  	action_fn  fn = (action_fn) kp->arg;
  	int        rv = 0;
  	char       valcp[16];
  	char       *s;
  
  	strncpy(valcp, val, 15);
  	valcp[15] = '\0';
  
  	s = strstrip(valcp);
  
  	rv = fn(s, NULL);
  	if (rv)
  		goto out;
  
  	check_parms();
  	if (watchdog_user)
  		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
  
   out:
  	return rv;
  }
  
  static int get_param_str(char *buffer, const struct kernel_param *kp)
  {
  	action_fn fn = (action_fn) kp->arg;
  	int rv, len;
  
  	rv = fn(NULL, buffer);
  	if (rv)
  		return rv;
  
  	len = strlen(buffer);
  	buffer[len++] = '\n';
  	buffer[len] = 0;
  
  	return len;
  }
  
  
  static int set_param_wdog_ifnum(const char *val, const struct kernel_param *kp)
  {
  	int rv = param_set_int(val, kp);
  	if (rv)
  		return rv;
  	if ((ifnum_to_use < 0) || (ifnum_to_use == watchdog_ifnum))
  		return 0;
  
  	ipmi_unregister_watchdog(watchdog_ifnum);
  	ipmi_register_watchdog(ifnum_to_use);
  	return 0;
  }
  
  static const struct kernel_param_ops param_ops_wdog_ifnum = {
  	.set = set_param_wdog_ifnum,
  	.get = param_get_int,
  };
  
  #define param_check_wdog_ifnum param_check_int
  
  static const struct kernel_param_ops param_ops_str = {
  	.set = set_param_str,
  	.get = get_param_str,
  };
  
  module_param(ifnum_to_use, wdog_ifnum, 0644);
  MODULE_PARM_DESC(ifnum_to_use, "The interface number to use for the watchdog "
  		 "timer.  Setting to -1 defaults to the first registered "
  		 "interface");
  
  module_param(timeout, timeout, 0644);
  MODULE_PARM_DESC(timeout, "Timeout value in seconds.");
  
  module_param(pretimeout, timeout, 0644);
  MODULE_PARM_DESC(pretimeout, "Pretimeout value in seconds.");
  
  module_param(panic_wdt_timeout, timeout, 0644);
  MODULE_PARM_DESC(panic_wdt_timeout, "Timeout value on kernel panic in seconds.");
  
  module_param_cb(action, &param_ops_str, action_op, 0644);
  MODULE_PARM_DESC(action, "Timeout action. One of: "
  		 "reset, none, power_cycle, power_off.");
  
  module_param_cb(preaction, &param_ops_str, preaction_op, 0644);
  MODULE_PARM_DESC(preaction, "Pretimeout action.  One of: "
  		 "pre_none, pre_smi, pre_nmi, pre_int.");
  
  module_param_cb(preop, &param_ops_str, preop_op, 0644);
  MODULE_PARM_DESC(preop, "Pretimeout driver operation.  One of: "
  		 "preop_none, preop_panic, preop_give_data.");
  
  module_param(start_now, int, 0444);
  MODULE_PARM_DESC(start_now, "Set to 1 to start the watchdog as"
  		 "soon as the driver is loaded.");
  
  module_param(nowayout, bool, 0644);
  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;
  
  /* Is someone using the watchdog?  Only one user is allowed. */
  static unsigned long ipmi_wdog_open;
  
  /*
   * 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;
  
  /* IPMI version of the BMC. */
  static unsigned char ipmi_version_major;
  static unsigned char ipmi_version_minor;
  
  /* If a pretimeout occurs, this is used to allow only one panic to happen. */
  static atomic_t preop_panic_excl = ATOMIC_INIT(-1);
  
  #ifdef HAVE_DIE_NMI
  static int testing_nmi;
  static int nmi_handler_registered;
  #endif
  
  static int __ipmi_heartbeat(void);
  
  /*
   * We use a mutex to make sure that only one thing can send a set a
   * message at one time.  The mutex is claimed when a message is sent
   * and freed when both the send and receive messages are free.
   */
  static atomic_t msg_tofree = ATOMIC_INIT(0);
  static DECLARE_COMPLETION(msg_wait);
  static void msg_free_smi(struct ipmi_smi_msg *msg)
  {
  	if (atomic_dec_and_test(&msg_tofree)) {
  		if (!oops_in_progress)
  			complete(&msg_wait);
  	}
  }
  static void msg_free_recv(struct ipmi_recv_msg *msg)
  {
  	if (atomic_dec_and_test(&msg_tofree)) {
  		if (!oops_in_progress)
  			complete(&msg_wait);
  	}
  }
  static struct ipmi_smi_msg smi_msg = {
  	.done = msg_free_smi
  };
  static struct ipmi_recv_msg recv_msg = {
  	.done = msg_free_recv
  };
  
  static int __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_watchdog_state != WDOG_TIMEOUT_NONE) {
  		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 {
  			/*
  			 * 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) && (ipmi_watchdog_state != WDOG_TIMEOUT_NONE)) {
  	    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)
  		pr_warn("set timeout error: %d\n", rv);
  	else if (send_heartbeat_now)
  		*send_heartbeat_now = hbnow;
  
  	return rv;
  }
  
  static int _ipmi_set_timeout(int do_heartbeat)
  {
  	int send_heartbeat_now;
  	int rv;
  
  	if (!watchdog_user)
  		return -ENODEV;
  
  	atomic_set(&msg_tofree, 2);
  
  	rv = __ipmi_set_timeout(&smi_msg,
  				&recv_msg,
  				&send_heartbeat_now);
  	if (rv) {
  		atomic_set(&msg_tofree, 0);
  		return rv;
  	}
  
  	wait_for_completion(&msg_wait);
  
  	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 int ipmi_set_timeout(int do_heartbeat)
  {
  	int rv;
  
  	mutex_lock(&ipmi_watchdog_mutex);
  	rv = _ipmi_set_timeout(do_heartbeat);
  	mutex_unlock(&ipmi_watchdog_mutex);
  
  	return rv;
  }
  
  static atomic_t panic_done_count = ATOMIC_INIT(0);
  
  static void panic_smi_free(struct ipmi_smi_msg *msg)
  {
  	atomic_dec(&panic_done_count);
  }
  static void panic_recv_free(struct ipmi_recv_msg *msg)
  {
  	atomic_dec(&panic_done_count);
  }
  
  static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg = {
  	.done = panic_smi_free
  };
  static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg = {
  	.done = panic_recv_free
  };
  
  static void panic_halt_ipmi_heartbeat(void)
  {
  	struct kernel_ipmi_msg             msg;
  	struct ipmi_system_interface_addr addr;
  	int rv;
  
  	/*
  	 * 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;
  	atomic_add(2, &panic_done_count);
  	rv = ipmi_request_supply_msgs(watchdog_user,
  				      (struct ipmi_addr *) &addr,
  				      0,
  				      &msg,
  				      NULL,
  				      &panic_halt_heartbeat_smi_msg,
  				      &panic_halt_heartbeat_recv_msg,
  				      1);
  	if (rv)
  		atomic_sub(2, &panic_done_count);
  }
  
  static struct ipmi_smi_msg panic_halt_smi_msg = {
  	.done = panic_smi_free
  };
  static struct ipmi_recv_msg panic_halt_recv_msg = {
  	.done = panic_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;
  
  	/* Wait for the messages to be free. */
  	while (atomic_read(&panic_done_count) != 0)
  		ipmi_poll_interface(watchdog_user);
  	atomic_add(2, &panic_done_count);
  	rv = __ipmi_set_timeout(&panic_halt_smi_msg,
  				&panic_halt_recv_msg,
  				&send_heartbeat_now);
  	if (rv) {
  		atomic_sub(2, &panic_done_count);
  		pr_warn("Unable to extend the watchdog timeout\n");
  	} else {
  		if (send_heartbeat_now)
  			panic_halt_ipmi_heartbeat();
  	}
  	while (atomic_read(&panic_done_count) != 0)
  		ipmi_poll_interface(watchdog_user);
  }
  
  static int __ipmi_heartbeat(void)
  {
  	struct kernel_ipmi_msg msg;
  	int rv;
  	struct ipmi_system_interface_addr addr;
  	int timeout_retries = 0;
  
  restart:
  	/*
  	 * 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 0;
  
  	atomic_set(&msg_tofree, 2);
  
  	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,
  				      &smi_msg,
  				      &recv_msg,
  				      1);
  	if (rv) {
  		atomic_set(&msg_tofree, 0);
  		pr_warn("heartbeat send failure: %d\n", rv);
  		return rv;
  	}
  
  	/* Wait for the heartbeat to be sent. */
  	wait_for_completion(&msg_wait);
  
  	if (recv_msg.msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)  {
  		timeout_retries++;
  		if (timeout_retries > 3) {
  			pr_err("Unable to restore the IPMI watchdog's settings, giving up\n");
  			rv = -EIO;
  			goto out;
  		}
  
  		/*
  		 * The timer was not initialized, that means the BMC was
  		 * probably reset and lost the watchdog information.  Attempt
  		 * to restore the timer's info.  Note that we still hold
  		 * the heartbeat lock, to keep a heartbeat from happening
  		 * in this process, so must say no heartbeat to avoid a
  		 * deadlock on this mutex
  		 */
  		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
  		if (rv) {
  			pr_err("Unable to send the command to set the watchdog's settings, giving up\n");
  			goto out;
  		}
  
  		/* Might need a heartbeat send, go ahead and do it. */
  		goto restart;
  	} else if (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;
  	}
  
  out:
  	return rv;
  }
  
  static int _ipmi_heartbeat(void)
  {
  	int rv;
  
  	if (!watchdog_user)
  		return -ENODEV;
  
  	if (ipmi_start_timer_on_heartbeat) {
  		ipmi_start_timer_on_heartbeat = 0;
  		ipmi_watchdog_state = action_val;
  		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
  	} else if (atomic_cmpxchg(&pretimeout_since_last_heartbeat, 1, 0)) {
  		/*
  		 * 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.
  		 */
  		rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
  	} else {
  		rv = __ipmi_heartbeat();
  	}
  
  	return rv;
  }
  
  static int ipmi_heartbeat(void)
  {
  	int rv;
  
  	mutex_lock(&ipmi_watchdog_mutex);
  	rv = _ipmi_heartbeat();
  	mutex_unlock(&ipmi_watchdog_mutex);
  
  	return rv;
  }
  
  static const struct watchdog_info ident = {
  	.options	= 0,	/* WDIOF_SETTIMEOUT, */
  	.firmware_version = 1,
  	.identity	= "IPMI"
  };
  
  static int ipmi_ioctl(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_SETPRETIMEOUT:
  		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_GETPRETIMEOUT:
  		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 long ipmi_unlocked_ioctl(struct file *file,
  				unsigned int cmd,
  				unsigned long arg)
  {
  	int ret;
  
  	mutex_lock(&ipmi_watchdog_mutex);
  	ret = ipmi_ioctl(file, cmd, arg);
  	mutex_unlock(&ipmi_watchdog_mutex);
  
  	return ret;
  }
  
  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 len;
  }
  
  static ssize_t ipmi_read(struct file *file,
  			 char        __user *buf,
  			 size_t      count,
  			 loff_t      *ppos)
  {
  	int          rv = 0;
  	wait_queue_entry_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_irq(&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_irq(&ipmi_read_lock);
  			schedule();
  			spin_lock_irq(&ipmi_read_lock);
  		}
  		remove_wait_queue(&read_q, &wait);
  
  		if (signal_pending(current)) {
  			rv = -ERESTARTSYS;
  			goto out;
  		}
  	}
  	data_to_read = 0;
  
   out:
  	spin_unlock_irq(&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 stream_open(ino, filep);
  
  	default:
  		return (-ENODEV);
  	}
  }
  
  static __poll_t ipmi_poll(struct file *file, poll_table *wait)
  {
  	__poll_t mask = 0;
  
  	poll_wait(file, &read_q, wait);
  
  	spin_lock_irq(&ipmi_read_lock);
  	if (data_to_read)
  		mask |= (EPOLLIN | EPOLLRDNORM);
  	spin_unlock_irq(&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) {
  			mutex_lock(&ipmi_watchdog_mutex);
  			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
  			_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
  			mutex_unlock(&ipmi_watchdog_mutex);
  		} else {
  			pr_crit("Unexpected close, not stopping watchdog!\n");
  			ipmi_heartbeat();
  		}
  		clear_bit(0, &ipmi_wdog_open);
  	}
  
  	expect_close = 0;
  
  	return 0;
  }
  
  static const struct file_operations ipmi_wdog_fops = {
  	.owner   = THIS_MODULE,
  	.read    = ipmi_read,
  	.poll    = ipmi_poll,
  	.write   = ipmi_write,
  	.unlocked_ioctl = ipmi_unlocked_ioctl,
  	.compat_ioctl	= compat_ptr_ioctl,
  	.open    = ipmi_open,
  	.release = ipmi_close,
  	.fasync  = ipmi_fasync,
  	.llseek  = no_llseek,
  };
  
  static struct miscdevice ipmi_wdog_miscdev = {
  	.minor		= WATCHDOG_MINOR,
  	.name		= "watchdog",
  	.fops		= &ipmi_wdog_fops
  };
  
  static void ipmi_wdog_msg_handler(struct ipmi_recv_msg *msg,
  				  void                 *handler_data)
  {
  	if (msg->msg.cmd == IPMI_WDOG_RESET_TIMER &&
  			msg->msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)
  		pr_info("response: The IPMI controller appears to have been reset, will attempt to reinitialize the watchdog timer\n");
  	else if (msg->msg.data[0] != 0)
  		pr_err("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) {
  			if (atomic_inc_and_test(&preop_panic_excl))
  				panic("Watchdog pre-timeout");
  		} else if (preop_val == WDOG_PREOP_GIVE_DATA) {
  			unsigned long flags;
  
  			spin_lock_irqsave(&ipmi_read_lock, flags);
  			data_to_read = 1;
  			wake_up_interruptible(&read_q);
  			kill_fasync(&fasync_q, SIGIO, POLL_IN);
  			spin_unlock_irqrestore(&ipmi_read_lock, flags);
  		}
  	}
  
  	/*
  	 * On some machines, the heartbeat will give an error and not
  	 * work unless we re-enable the timer.  So do so.
  	 */
  	atomic_set(&pretimeout_since_last_heartbeat, 1);
  }
  
  static void ipmi_wdog_panic_handler(void *user_data)
  {
  	static int panic_event_handled;
  
  	/*
  	 * On a panic, if we have a panic timeout, make sure to extend
  	 * the watchdog timer to a reasonable value to complete the
  	 * panic, if the watchdog timer is running.  Plus the
  	 * pretimeout is meaningless at panic time.
  	 */
  	if (watchdog_user && !panic_event_handled &&
  	    ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
  		/* Make sure we do this only once. */
  		panic_event_handled = 1;
  
  		timeout = panic_wdt_timeout;
  		pretimeout = 0;
  		panic_halt_ipmi_set_timeout();
  	}
  }
  
  static const struct ipmi_user_hndl ipmi_hndlrs = {
  	.ipmi_recv_hndl           = ipmi_wdog_msg_handler,
  	.ipmi_watchdog_pretimeout = ipmi_wdog_pretimeout_handler,
  	.ipmi_panic_handler       = ipmi_wdog_panic_handler
  };
  
  static void ipmi_register_watchdog(int ipmi_intf)
  {
  	int rv = -EBUSY;
  
  	if (watchdog_user)
  		goto out;
  
  	if ((ifnum_to_use >= 0) && (ifnum_to_use != ipmi_intf))
  		goto out;
  
  	watchdog_ifnum = ipmi_intf;
  
  	rv = ipmi_create_user(ipmi_intf, &ipmi_hndlrs, NULL, &watchdog_user);
  	if (rv < 0) {
  		pr_crit("Unable to register with ipmi\n");
  		goto out;
  	}
  
  	rv = ipmi_get_version(watchdog_user,
  			      &ipmi_version_major,
  			      &ipmi_version_minor);
  	if (rv) {
  		pr_warn("Unable to get IPMI version, assuming 1.0\n");
  		ipmi_version_major = 1;
  		ipmi_version_minor = 0;
  	}
  
  	rv = misc_register(&ipmi_wdog_miscdev);
  	if (rv < 0) {
  		ipmi_destroy_user(watchdog_user);
  		watchdog_user = NULL;
  		pr_crit("Unable to register misc device\n");
  	}
  
  #ifdef HAVE_DIE_NMI
  	if (nmi_handler_registered) {
  		int old_pretimeout = pretimeout;
  		int old_timeout = timeout;
  		int old_preop_val = preop_val;
  
  		/*
  		 * Set the pretimeout to go off in a second and give
  		 * ourselves plenty of time to stop the timer.
  		 */
  		ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
  		preop_val = WDOG_PREOP_NONE; /* Make sure nothing happens */
  		pretimeout = 99;
  		timeout = 100;
  
  		testing_nmi = 1;
  
  		rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
  		if (rv) {
  			pr_warn("Error starting timer to test NMI: 0x%x.  The NMI pretimeout will likely not work\n",
  				rv);
  			rv = 0;
  			goto out_restore;
  		}
  
  		msleep(1500);
  
  		if (testing_nmi != 2) {
  			pr_warn("IPMI NMI didn't seem to occur.  The NMI pretimeout will likely not work\n");
  		}
   out_restore:
  		testing_nmi = 0;
  		preop_val = old_preop_val;
  		pretimeout = old_pretimeout;
  		timeout = old_timeout;
  	}
  #endif
  
   out:
  	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);
  		pr_info("Starting now!\n");
  	} else {
  		/* Stop the timer now. */
  		ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
  		ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
  	}
  }
  
  static void ipmi_unregister_watchdog(int ipmi_intf)
  {
  	int rv;
  	struct ipmi_user *loc_user = watchdog_user;
  
  	if (!loc_user)
  		return;
  
  	if (watchdog_ifnum != ipmi_intf)
  		return;
  
  	/* Make sure no one can call us any more. */
  	misc_deregister(&ipmi_wdog_miscdev);
  
  	watchdog_user = NULL;
  
  	/*
  	 * 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(&msg_tofree))
  		msg_free_smi(NULL);
  
  	mutex_lock(&ipmi_watchdog_mutex);
  
  	/* Disconnect from IPMI. */
  	rv = ipmi_destroy_user(loc_user);
  	if (rv)
  		pr_warn("error unlinking from IPMI: %d\n",  rv);
  
  	/* If it comes back, restart it properly. */
  	ipmi_start_timer_on_heartbeat = 1;
  
  	mutex_unlock(&ipmi_watchdog_mutex);
  }
  
  #ifdef HAVE_DIE_NMI
  static int
  ipmi_nmi(unsigned int val, struct pt_regs *regs)
  {
  	/*
  	 * If we get here, it's an NMI that's not a memory or I/O
  	 * error.  We can't truly tell if it's from IPMI or not
  	 * without sending a message, and sending a message is almost
  	 * impossible because of locking.
  	 */
  
  	if (testing_nmi) {
  		testing_nmi = 2;
  		return NMI_HANDLED;
  	}
  
  	/* If we are not expecting a timeout, ignore it. */
  	if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
  		return NMI_DONE;
  
  	if (preaction_val != WDOG_PRETIMEOUT_NMI)
  		return NMI_DONE;
  
  	/*
  	 * If no one else handled the NMI, we assume it was the IPMI
  	 * watchdog.
  	 */
  	if (preop_val == WDOG_PREOP_PANIC) {
  		/* On some machines, the heartbeat will give
  		   an error and not work unless we re-enable
  		   the timer.   So do so. */
  		atomic_set(&pretimeout_since_last_heartbeat, 1);
  		if (atomic_inc_and_test(&preop_panic_excl))
  			nmi_panic(regs, "pre-timeout");
  	}
  
  	return NMI_HANDLED;
  }
  #endif
  
  static int wdog_reboot_handler(struct notifier_block *this,
  			       unsigned long         code,
  			       void                  *unused)
  {
  	static int reboot_event_handled;
  
  	if ((watchdog_user) && (!reboot_event_handled)) {
  		/* Make sure we only do this once. */
  		reboot_event_handled = 1;
  
  		if (code == SYS_POWER_OFF || code == SYS_HALT) {
  			/* Disable the WDT if we are shutting down. */
  			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
  			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
  		} else if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
  			/* Set a long timer to let the reboot happen or
  			   reset if it hangs, but only if the watchdog
  			   timer was already running. */
  			if (timeout < 120)
  				timeout = 120;
  			pretimeout = 0;
  			ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
  			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
  		}
  	}
  	return NOTIFY_OK;
  }
  
  static struct notifier_block wdog_reboot_notifier = {
  	.notifier_call	= wdog_reboot_handler,
  	.next		= NULL,
  	.priority	= 0
  };
  
  static void ipmi_new_smi(int if_num, struct device *device)
  {
  	ipmi_register_watchdog(if_num);
  }
  
  static void ipmi_smi_gone(int if_num)
  {
  	ipmi_unregister_watchdog(if_num);
  }
  
  static struct ipmi_smi_watcher smi_watcher = {
  	.owner    = THIS_MODULE,
  	.new_smi  = ipmi_new_smi,
  	.smi_gone = ipmi_smi_gone
  };
  
  static int action_op(const char *inval, char *outval)
  {
  	if (outval)
  		strcpy(outval, action);
  
  	if (!inval)
  		return 0;
  
  	if (strcmp(inval, "reset") == 0)
  		action_val = WDOG_TIMEOUT_RESET;
  	else if (strcmp(inval, "none") == 0)
  		action_val = WDOG_TIMEOUT_NONE;
  	else if (strcmp(inval, "power_cycle") == 0)
  		action_val = WDOG_TIMEOUT_POWER_CYCLE;
  	else if (strcmp(inval, "power_off") == 0)
  		action_val = WDOG_TIMEOUT_POWER_DOWN;
  	else
  		return -EINVAL;
  	strcpy(action, inval);
  	return 0;
  }
  
  static int preaction_op(const char *inval, char *outval)
  {
  	if (outval)
  		strcpy(outval, preaction);
  
  	if (!inval)
  		return 0;
  
  	if (strcmp(inval, "pre_none") == 0)
  		preaction_val = WDOG_PRETIMEOUT_NONE;
  	else if (strcmp(inval, "pre_smi") == 0)
  		preaction_val = WDOG_PRETIMEOUT_SMI;
  #ifdef HAVE_DIE_NMI
  	else if (strcmp(inval, "pre_nmi") == 0)
  		preaction_val = WDOG_PRETIMEOUT_NMI;
  #endif
  	else if (strcmp(inval, "pre_int") == 0)
  		preaction_val = WDOG_PRETIMEOUT_MSG_INT;
  	else
  		return -EINVAL;
  	strcpy(preaction, inval);
  	return 0;
  }
  
  static int preop_op(const char *inval, char *outval)
  {
  	if (outval)
  		strcpy(outval, preop);
  
  	if (!inval)
  		return 0;
  
  	if (strcmp(inval, "preop_none") == 0)
  		preop_val = WDOG_PREOP_NONE;
  	else if (strcmp(inval, "preop_panic") == 0)
  		preop_val = WDOG_PREOP_PANIC;
  	else if (strcmp(inval, "preop_give_data") == 0)
  		preop_val = WDOG_PREOP_GIVE_DATA;
  	else
  		return -EINVAL;
  	strcpy(preop, inval);
  	return 0;
  }
  
  static void check_parms(void)
  {
  #ifdef HAVE_DIE_NMI
  	int do_nmi = 0;
  	int rv;
  
  	if (preaction_val == WDOG_PRETIMEOUT_NMI) {
  		do_nmi = 1;
  		if (preop_val == WDOG_PREOP_GIVE_DATA) {
  			pr_warn("Pretimeout op is to give data but NMI pretimeout is enabled, setting pretimeout op to none\n");
  			preop_op("preop_none", NULL);
  			do_nmi = 0;
  		}
  	}
  	if (do_nmi && !nmi_handler_registered) {
  		rv = register_nmi_handler(NMI_UNKNOWN, ipmi_nmi, 0,
  						"ipmi");
  		if (rv) {
  			pr_warn("Can't register nmi handler\n");
  			return;
  		} else
  			nmi_handler_registered = 1;
  	} else if (!do_nmi && nmi_handler_registered) {
  		unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
  		nmi_handler_registered = 0;
  	}
  #endif
  }
  
  static int __init ipmi_wdog_init(void)
  {
  	int rv;
  
  	if (action_op(action, NULL)) {
  		action_op("reset", NULL);
  		pr_info("Unknown action '%s', defaulting to reset\n", action);
  	}
  
  	if (preaction_op(preaction, NULL)) {
  		preaction_op("pre_none", NULL);
  		pr_info("Unknown preaction '%s', defaulting to none\n",
  			preaction);
  	}
  
  	if (preop_op(preop, NULL)) {
  		preop_op("preop_none", NULL);
  		pr_info("Unknown preop '%s', defaulting to none\n", preop);
  	}
  
  	check_parms();
  
  	register_reboot_notifier(&wdog_reboot_notifier);
  
  	rv = ipmi_smi_watcher_register(&smi_watcher);
  	if (rv) {
  #ifdef HAVE_DIE_NMI
  		if (nmi_handler_registered)
  			unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
  #endif
  		unregister_reboot_notifier(&wdog_reboot_notifier);
  		pr_warn("can't register smi watcher\n");
  		return rv;
  	}
  
  	pr_info("driver initialized\n");
  
  	return 0;
  }
  
  static void __exit ipmi_wdog_exit(void)
  {
  	ipmi_smi_watcher_unregister(&smi_watcher);
  	ipmi_unregister_watchdog(watchdog_ifnum);
  
  #ifdef HAVE_DIE_NMI
  	if (nmi_handler_registered)
  		unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
  #endif
  
  	unregister_reboot_notifier(&wdog_reboot_notifier);
  }
  module_exit(ipmi_wdog_exit);
  module_init(ipmi_wdog_init);
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Corey Minyard <minyard@mvista.com>");
  MODULE_DESCRIPTION("watchdog timer based upon the IPMI interface.");
  