ipmi_msghandler.c

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/*
 * ipmi_msghandler.c
 *
 * Incoming and outgoing message routing for an IPMI interface.
 *
 * Author: MontaVista Software, Inc.
 *         Corey Minyard <[email protected]>
 *         [email protected]
 *
 * 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/module.h>
#include <linux/errno.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/ipmi.h>
#include <linux/ipmi_smi.h>
#include <linux/notifier.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/rcupdate.h>
#include <linux/interrupt.h>

#define PFX "IPMI message handler: "

#define IPMI_DRIVER_VERSION "39.2"

static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void);
static int ipmi_init_msghandler(void);
static void smi_recv_tasklet(unsigned long);
static void handle_new_recv_msgs(ipmi_smi_t intf);

static int initialized;

#ifdef CONFIG_PROC_FS
static struct proc_dir_entry *proc_ipmi_root;
#endif /* CONFIG_PROC_FS */

/* Remain in auto-maintenance mode for this amount of time (in ms). */
#define IPMI_MAINTENANCE_MODE_TIMEOUT 30000

#define MAX_EVENTS_IN_QUEUE 25

/*
 * Don't let a message sit in a queue forever, always time it with at lest
 * the max message timer.  This is in milliseconds.
 */
#define MAX_MSG_TIMEOUT     60000

/*
 * The main "user" data structure.
 */
struct ipmi_user {
    struct list_head link;

    /* Set to "0" when the user is destroyed. */
    int valid;

    struct kref refcount;

    /* The upper layer that handles receive messages. */
    struct ipmi_user_hndl *handler;
    void             *handler_data;

    /* The interface this user is bound to. */
    ipmi_smi_t intf;

    /* Does this interface receive IPMI events? */
    int gets_events;
};

struct cmd_rcvr {
    struct list_head link;

    ipmi_user_t   user;
    unsigned char netfn;
    unsigned char cmd;
    unsigned int  chans;

    /*
     * This is used to form a linked lised during mass deletion.
     * Since this is in an RCU list, we cannot use the link above
     * or change any data until the RCU period completes.  So we
     * use this next variable during mass deletion so we can have
     * a list and don't have to wait and restart the search on
     * every individual deletion of a command.
     */
    struct cmd_rcvr *next;
};

struct seq_table {
    unsigned int         inuse : 1;
    unsigned int         broadcast : 1;

    unsigned long        timeout;
    unsigned long        orig_timeout;
    unsigned int         retries_left;

    /*
     * To verify on an incoming send message response that this is
     * the message that the response is for, we keep a sequence id
     * and increment it every time we send a message.
     */
    long                 seqid;

    /*
     * This is held so we can properly respond to the message on a
     * timeout, and it is used to hold the temporary data for
     * retransmission, too.
     */
    struct ipmi_recv_msg *recv_msg;
};

/*
 * Store the information in a msgid (long) to allow us to find a
 * sequence table entry from the msgid.
 */
#define STORE_SEQ_IN_MSGID(seq, seqid) (((seq&0xff)<<26) | (seqid&0x3ffffff))

#define GET_SEQ_FROM_MSGID(msgid, seq, seqid) \
    do {                                \
        seq = ((msgid >> 26) & 0x3f);               \
        seqid = (msgid & 0x3fffff);             \
    } while (0)

#define NEXT_SEQID(seqid) (((seqid) + 1) & 0x3fffff)

struct ipmi_channel {
    unsigned char medium;
    unsigned char protocol;

    /*
     * My slave address.  This is initialized to IPMI_BMC_SLAVE_ADDR,
     * but may be changed by the user.
     */
    unsigned char address;

    /*
     * My LUN.  This should generally stay the SMS LUN, but just in
     * case...
     */
    unsigned char lun;
};

#ifdef CONFIG_PROC_FS
struct ipmi_proc_entry {
    char                   *name;
    struct ipmi_proc_entry *next;
};
#endif

struct bmc_device {
    struct platform_device *dev;
    struct ipmi_device_id  id;
    unsigned char          guid[16];
    int                    guid_set;

    struct kref        refcount;

    /* bmc device attributes */
    struct device_attribute device_id_attr;
    struct device_attribute provides_dev_sdrs_attr;
    struct device_attribute revision_attr;
    struct device_attribute firmware_rev_attr;
    struct device_attribute version_attr;
    struct device_attribute add_dev_support_attr;
    struct device_attribute manufacturer_id_attr;
    struct device_attribute product_id_attr;
    struct device_attribute guid_attr;
    struct device_attribute aux_firmware_rev_attr;
};

/*
 * Various statistics for IPMI, these index stats[] in the ipmi_smi
 * structure.
 */
enum ipmi_stat_indexes {
    /* Commands we got from the user that were invalid. */
    IPMI_STAT_sent_invalid_commands = 0,

    /* Commands we sent to the MC. */
    IPMI_STAT_sent_local_commands,

    /* Responses from the MC that were delivered to a user. */
    IPMI_STAT_handled_local_responses,

    /* Responses from the MC that were not delivered to a user. */
    IPMI_STAT_unhandled_local_responses,

    /* Commands we sent out to the IPMB bus. */
    IPMI_STAT_sent_ipmb_commands,

    /* Commands sent on the IPMB that had errors on the SEND CMD */
    IPMI_STAT_sent_ipmb_command_errs,

    /* Each retransmit increments this count. */
    IPMI_STAT_retransmitted_ipmb_commands,

    /*
     * When a message times out (runs out of retransmits) this is
     * incremented.
     */
    IPMI_STAT_timed_out_ipmb_commands,

    /*
     * This is like above, but for broadcasts.  Broadcasts are
     * *not* included in the above count (they are expected to
     * time out).
     */
    IPMI_STAT_timed_out_ipmb_broadcasts,

    /* Responses I have sent to the IPMB bus. */
    IPMI_STAT_sent_ipmb_responses,

    /* The response was delivered to the user. */
    IPMI_STAT_handled_ipmb_responses,

    /* The response had invalid data in it. */
    IPMI_STAT_invalid_ipmb_responses,

    /* The response didn't have anyone waiting for it. */
    IPMI_STAT_unhandled_ipmb_responses,

    /* Commands we sent out to the IPMB bus. */
    IPMI_STAT_sent_lan_commands,

    /* Commands sent on the IPMB that had errors on the SEND CMD */
    IPMI_STAT_sent_lan_command_errs,

    /* Each retransmit increments this count. */
    IPMI_STAT_retransmitted_lan_commands,

    /*
     * When a message times out (runs out of retransmits) this is
     * incremented.
     */
    IPMI_STAT_timed_out_lan_commands,

    /* Responses I have sent to the IPMB bus. */
    IPMI_STAT_sent_lan_responses,

    /* The response was delivered to the user. */
    IPMI_STAT_handled_lan_responses,

    /* The response had invalid data in it. */
    IPMI_STAT_invalid_lan_responses,

    /* The response didn't have anyone waiting for it. */
    IPMI_STAT_unhandled_lan_responses,

    /* The command was delivered to the user. */
    IPMI_STAT_handled_commands,

    /* The command had invalid data in it. */
    IPMI_STAT_invalid_commands,

    /* The command didn't have anyone waiting for it. */
    IPMI_STAT_unhandled_commands,

    /* Invalid data in an event. */
    IPMI_STAT_invalid_events,

    /* Events that were received with the proper format. */
    IPMI_STAT_events,

    /* Retransmissions on IPMB that failed. */
    IPMI_STAT_dropped_rexmit_ipmb_commands,

    /* Retransmissions on LAN that failed. */
    IPMI_STAT_dropped_rexmit_lan_commands,

    /* This *must* remain last, add new values above this. */
    IPMI_NUM_STATS
};


#define IPMI_IPMB_NUM_SEQ   64
#define IPMI_MAX_CHANNELS       16
struct ipmi_smi {
    /* What interface number are we? */
    int intf_num;

    struct kref refcount;

    /* Used for a list of interfaces. */
    struct list_head link;

    /*
     * The list of upper layers that are using me.  seq_lock
     * protects this.
     */
    struct list_head users;

    /* Information to supply to users. */
    unsigned char ipmi_version_major;
    unsigned char ipmi_version_minor;

    /* Used for wake ups at startup. */
    wait_queue_head_t waitq;

    struct bmc_device *bmc;
    char *my_dev_name;
    char *sysfs_name;

    /*
     * This is the lower-layer's sender routine.  Note that you
     * must either be holding the ipmi_interfaces_mutex or be in
     * an umpreemptible region to use this.  You must fetch the
     * value into a local variable and make sure it is not NULL.
     */
    struct ipmi_smi_handlers *handlers;
    void                     *send_info;

#ifdef CONFIG_PROC_FS
    /* A list of proc entries for this interface. */
    struct mutex           proc_entry_lock;
    struct ipmi_proc_entry *proc_entries;
#endif

    /* Driver-model device for the system interface. */
    struct device          *si_dev;

    /*
     * A table of sequence numbers for this interface.  We use the
     * sequence numbers for IPMB messages that go out of the
     * interface to match them up with their responses.  A routine
     * is called periodically to time the items in this list.
     */
    spinlock_t       seq_lock;
    struct seq_table seq_table[IPMI_IPMB_NUM_SEQ];
    int curr_seq;

    /*
     * Messages queued for delivery.  If delivery fails (out of memory
     * for instance), They will stay in here to be processed later in a
     * periodic timer interrupt.  The tasklet is for handling received
     * messages directly from the handler.
     */
    spinlock_t       waiting_msgs_lock;
    struct list_head waiting_msgs;
    atomic_t     watchdog_pretimeouts_to_deliver;
    struct tasklet_struct recv_tasklet;

    /*
     * The list of command receivers that are registered for commands
     * on this interface.
     */
    struct mutex     cmd_rcvrs_mutex;
    struct list_head cmd_rcvrs;

    /*
     * Events that were queues because no one was there to receive
     * them.
     */
    spinlock_t       events_lock; /* For dealing with event stuff. */
    struct list_head waiting_events;
    unsigned int     waiting_events_count; /* How many events in queue? */
    char             delivering_events;
    char             event_msg_printed;

    /*
     * The event receiver for my BMC, only really used at panic
     * shutdown as a place to store this.
     */
    unsigned char event_receiver;
    unsigned char event_receiver_lun;
    unsigned char local_sel_device;
    unsigned char local_event_generator;

    /* For handling of maintenance mode. */
    int maintenance_mode;
    int maintenance_mode_enable;
    int auto_maintenance_timeout;
    spinlock_t maintenance_mode_lock; /* Used in a timer... */

    /*
     * A cheap hack, if this is non-null and a message to an
     * interface comes in with a NULL user, call this routine with
     * it.  Note that the message will still be freed by the
     * caller.  This only works on the system interface.
     */
    void (*null_user_handler)(ipmi_smi_t intf, struct ipmi_recv_msg *msg);

    /*
     * When we are scanning the channels for an SMI, this will
     * tell which channel we are scanning.
     */
    int curr_channel;

    /* Channel information */
    struct ipmi_channel channels[IPMI_MAX_CHANNELS];

    /* Proc FS stuff. */
    struct proc_dir_entry *proc_dir;
    char                  proc_dir_name[10];

    atomic_t stats[IPMI_NUM_STATS];

    /*
     * run_to_completion duplicate of smb_info, smi_info
     * and ipmi_serial_info structures. Used to decrease numbers of
     * parameters passed by "low" level IPMI code.
     */
    int run_to_completion;
};
#define to_si_intf_from_dev(device) container_of(device, struct ipmi_smi, dev)

static struct platform_driver ipmidriver = {
    .driver = {
        .name = "ipmi",
        .bus = &platform_bus_type
    }
};
static DEFINE_MUTEX(ipmidriver_mutex);

static LIST_HEAD(ipmi_interfaces);
static DEFINE_MUTEX(ipmi_interfaces_mutex);

/*
 * List of watchers that want to know when smi's are added and deleted.
 */
static LIST_HEAD(smi_watchers);
static DEFINE_MUTEX(smi_watchers_mutex);


#define ipmi_inc_stat(intf, stat) \
    atomic_inc(&(intf)->stats[IPMI_STAT_ ## stat])
#define ipmi_get_stat(intf, stat) \
    ((unsigned int) atomic_read(&(intf)->stats[IPMI_STAT_ ## stat]))

static int is_lan_addr(struct ipmi_addr *addr)
{
    return addr->addr_type == IPMI_LAN_ADDR_TYPE;
}

static int is_ipmb_addr(struct ipmi_addr *addr)
{
    return addr->addr_type == IPMI_IPMB_ADDR_TYPE;
}

static int is_ipmb_bcast_addr(struct ipmi_addr *addr)
{
    return addr->addr_type == IPMI_IPMB_BROADCAST_ADDR_TYPE;
}

static void free_recv_msg_list(struct list_head *q)
{
    struct ipmi_recv_msg *msg, *msg2;

    list_for_each_entry_safe(msg, msg2, q, link) {
        list_del(&msg->link);
        ipmi_free_recv_msg(msg);
    }
}

static void free_smi_msg_list(struct list_head *q)
{
    struct ipmi_smi_msg *msg, *msg2;

    list_for_each_entry_safe(msg, msg2, q, link) {
        list_del(&msg->link);
        ipmi_free_smi_msg(msg);
    }
}

static void clean_up_interface_data(ipmi_smi_t intf)
{
    int              i;
    struct cmd_rcvr  *rcvr, *rcvr2;
    struct list_head list;

    tasklet_kill(&intf->recv_tasklet);

    free_smi_msg_list(&intf->waiting_msgs);
    free_recv_msg_list(&intf->waiting_events);

    /*
     * Wholesale remove all the entries from the list in the
     * interface and wait for RCU to know that none are in use.
     */
    mutex_lock(&intf->cmd_rcvrs_mutex);
    INIT_LIST_HEAD(&list);
    list_splice_init_rcu(&intf->cmd_rcvrs, &list, synchronize_rcu);
    mutex_unlock(&intf->cmd_rcvrs_mutex);

    list_for_each_entry_safe(rcvr, rcvr2, &list, link)
        kfree(rcvr);

    for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++) {
        if ((intf->seq_table[i].inuse)
                    && (intf->seq_table[i].recv_msg))
            ipmi_free_recv_msg(intf->seq_table[i].recv_msg);
    }
}

static void intf_free(struct kref *ref)
{
    ipmi_smi_t intf = container_of(ref, struct ipmi_smi, refcount);

    clean_up_interface_data(intf);
    kfree(intf);
}

struct watcher_entry {
    int              intf_num;
    ipmi_smi_t       intf;
    struct list_head link;
};

int ipmi_smi_watcher_register(struct ipmi_smi_watcher *watcher)
{
    ipmi_smi_t intf;
    LIST_HEAD(to_deliver);
    struct watcher_entry *e, *e2;

    mutex_lock(&smi_watchers_mutex);

    mutex_lock(&ipmi_interfaces_mutex);

    /* Build a list of things to deliver. */
    list_for_each_entry(intf, &ipmi_interfaces, link) {
        if (intf->intf_num == -1)
            continue;
        e = kmalloc(sizeof(*e), GFP_KERNEL);
        if (!e)
            goto out_err;
        kref_get(&intf->refcount);
        e->intf = intf;
        e->intf_num = intf->intf_num;
        list_add_tail(&e->link, &to_deliver);
    }

    /* We will succeed, so add it to the list. */
    list_add(&watcher->link, &smi_watchers);

    mutex_unlock(&ipmi_interfaces_mutex);

    list_for_each_entry_safe(e, e2, &to_deliver, link) {
        list_del(&e->link);
        watcher->new_smi(e->intf_num, e->intf->si_dev);
        kref_put(&e->intf->refcount, intf_free);
        kfree(e);
    }

    mutex_unlock(&smi_watchers_mutex);

    return 0;

 out_err:
    mutex_unlock(&ipmi_interfaces_mutex);
    mutex_unlock(&smi_watchers_mutex);
    list_for_each_entry_safe(e, e2, &to_deliver, link) {
        list_del(&e->link);
        kref_put(&e->intf->refcount, intf_free);
        kfree(e);
    }
    return -ENOMEM;
}
EXPORT_SYMBOL(ipmi_smi_watcher_register);

int ipmi_smi_watcher_unregister(struct ipmi_smi_watcher *watcher)
{
    mutex_lock(&smi_watchers_mutex);
    list_del(&(watcher->link));
    mutex_unlock(&smi_watchers_mutex);
    return 0;
}
EXPORT_SYMBOL(ipmi_smi_watcher_unregister);

/*
 * Must be called with smi_watchers_mutex held.
 */
static void
call_smi_watchers(int i, struct device *dev)
{
    struct ipmi_smi_watcher *w;

    list_for_each_entry(w, &smi_watchers, link) {
        if (try_module_get(w->owner)) {
            w->new_smi(i, dev);
            module_put(w->owner);
        }
    }
}

static int
ipmi_addr_equal(struct ipmi_addr *addr1, struct ipmi_addr *addr2)
{
    if (addr1->addr_type != addr2->addr_type)
        return 0;

    if (addr1->channel != addr2->channel)
        return 0;

    if (addr1->addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE) {
        struct ipmi_system_interface_addr *smi_addr1
            = (struct ipmi_system_interface_addr *) addr1;
        struct ipmi_system_interface_addr *smi_addr2
            = (struct ipmi_system_interface_addr *) addr2;
        return (smi_addr1->lun == smi_addr2->lun);
    }

    if (is_ipmb_addr(addr1) || is_ipmb_bcast_addr(addr1)) {
        struct ipmi_ipmb_addr *ipmb_addr1
            = (struct ipmi_ipmb_addr *) addr1;
        struct ipmi_ipmb_addr *ipmb_addr2
            = (struct ipmi_ipmb_addr *) addr2;

        return ((ipmb_addr1->slave_addr == ipmb_addr2->slave_addr)
            && (ipmb_addr1->lun == ipmb_addr2->lun));
    }

    if (is_lan_addr(addr1)) {
        struct ipmi_lan_addr *lan_addr1
            = (struct ipmi_lan_addr *) addr1;
        struct ipmi_lan_addr *lan_addr2
            = (struct ipmi_lan_addr *) addr2;

        return ((lan_addr1->remote_SWID == lan_addr2->remote_SWID)
            && (lan_addr1->local_SWID == lan_addr2->local_SWID)
            && (lan_addr1->session_handle
                == lan_addr2->session_handle)
            && (lan_addr1->lun == lan_addr2->lun));
    }

    return 1;
}

int ipmi_validate_addr(struct ipmi_addr *addr, int len)
{
    if (len < sizeof(struct ipmi_system_interface_addr))
        return -EINVAL;

    if (addr->addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE) {
        if (addr->channel != IPMI_BMC_CHANNEL)
            return -EINVAL;
        return 0;
    }

    if ((addr->channel == IPMI_BMC_CHANNEL)
        || (addr->channel >= IPMI_MAX_CHANNELS)
        || (addr->channel < 0))
        return -EINVAL;

    if (is_ipmb_addr(addr) || is_ipmb_bcast_addr(addr)) {
        if (len < sizeof(struct ipmi_ipmb_addr))
            return -EINVAL;
        return 0;
    }

    if (is_lan_addr(addr)) {
        if (len < sizeof(struct ipmi_lan_addr))
            return -EINVAL;
        return 0;
    }

    return -EINVAL;
}
EXPORT_SYMBOL(ipmi_validate_addr);

unsigned int ipmi_addr_length(int addr_type)
{
    if (addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
        return sizeof(struct ipmi_system_interface_addr);

    if ((addr_type == IPMI_IPMB_ADDR_TYPE)
            || (addr_type == IPMI_IPMB_BROADCAST_ADDR_TYPE))
        return sizeof(struct ipmi_ipmb_addr);

    if (addr_type == IPMI_LAN_ADDR_TYPE)
        return sizeof(struct ipmi_lan_addr);

    return 0;
}
EXPORT_SYMBOL(ipmi_addr_length);

static void deliver_response(struct ipmi_recv_msg *msg)
{
    if (!msg->user) {
        ipmi_smi_t    intf = msg->user_msg_data;

        /* Special handling for NULL users. */
        if (intf->null_user_handler) {
            intf->null_user_handler(intf, msg);
            ipmi_inc_stat(intf, handled_local_responses);
        } else {
            /* No handler, so give up. */
            ipmi_inc_stat(intf, unhandled_local_responses);
        }
        ipmi_free_recv_msg(msg);
    } else {
        ipmi_user_t user = msg->user;
        user->handler->ipmi_recv_hndl(msg, user->handler_data);
    }
}

static void
deliver_err_response(struct ipmi_recv_msg *msg, int err)
{
    msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
    msg->msg_data[0] = err;
    msg->msg.netfn |= 1; /* Convert to a response. */
    msg->msg.data_len = 1;
    msg->msg.data = msg->msg_data;
    deliver_response(msg);
}

/*
 * Find the next sequence number not being used and add the given
 * message with the given timeout to the sequence table.  This must be
 * called with the interface's seq_lock held.
 */
static int intf_next_seq(ipmi_smi_t           intf,
             struct ipmi_recv_msg *recv_msg,
             unsigned long        timeout,
             int                  retries,
             int                  broadcast,
             unsigned char        *seq,
             long                 *seqid)
{
    int          rv = 0;
    unsigned int i;

    for (i = intf->curr_seq; (i+1)%IPMI_IPMB_NUM_SEQ != intf->curr_seq;
                    i = (i+1)%IPMI_IPMB_NUM_SEQ) {
        if (!intf->seq_table[i].inuse)
            break;
    }

    if (!intf->seq_table[i].inuse) {
        intf->seq_table[i].recv_msg = recv_msg;

        /*
         * Start with the maximum timeout, when the send response
         * comes in we will start the real timer.
         */
        intf->seq_table[i].timeout = MAX_MSG_TIMEOUT;
        intf->seq_table[i].orig_timeout = timeout;
        intf->seq_table[i].retries_left = retries;
        intf->seq_table[i].broadcast = broadcast;
        intf->seq_table[i].inuse = 1;
        intf->seq_table[i].seqid = NEXT_SEQID(intf->seq_table[i].seqid);
        *seq = i;
        *seqid = intf->seq_table[i].seqid;
        intf->curr_seq = (i+1)%IPMI_IPMB_NUM_SEQ;
    } else {
        rv = -EAGAIN;
    }

    return rv;
}

/*
 * Return the receive message for the given sequence number and
 * release the sequence number so it can be reused.  Some other data
 * is passed in to be sure the message matches up correctly (to help
 * guard against message coming in after their timeout and the
 * sequence number being reused).
 */
static int intf_find_seq(ipmi_smi_t           intf,
             unsigned char        seq,
             short                channel,
             unsigned char        cmd,
             unsigned char        netfn,
             struct ipmi_addr     *addr,
             struct ipmi_recv_msg **recv_msg)
{
    int           rv = -ENODEV;
    unsigned long flags;

    if (seq >= IPMI_IPMB_NUM_SEQ)
        return -EINVAL;

    spin_lock_irqsave(&(intf->seq_lock), flags);
    if (intf->seq_table[seq].inuse) {
        struct ipmi_recv_msg *msg = intf->seq_table[seq].recv_msg;

        if ((msg->addr.channel == channel) && (msg->msg.cmd == cmd)
                && (msg->msg.netfn == netfn)
                && (ipmi_addr_equal(addr, &(msg->addr)))) {
            *recv_msg = msg;
            intf->seq_table[seq].inuse = 0;
            rv = 0;
        }
    }
    spin_unlock_irqrestore(&(intf->seq_lock), flags);

    return rv;
}


/* Start the timer for a specific sequence table entry. */
static int intf_start_seq_timer(ipmi_smi_t intf,
                long       msgid)
{
    int           rv = -ENODEV;
    unsigned long flags;
    unsigned char seq;
    unsigned long seqid;


    GET_SEQ_FROM_MSGID(msgid, seq, seqid);

    spin_lock_irqsave(&(intf->seq_lock), flags);
    /*
     * We do this verification because the user can be deleted
     * while a message is outstanding.
     */
    if ((intf->seq_table[seq].inuse)
                && (intf->seq_table[seq].seqid == seqid)) {
        struct seq_table *ent = &(intf->seq_table[seq]);
        ent->timeout = ent->orig_timeout;
        rv = 0;
    }
    spin_unlock_irqrestore(&(intf->seq_lock), flags);

    return rv;
}

/* Got an error for the send message for a specific sequence number. */
static int intf_err_seq(ipmi_smi_t   intf,
            long         msgid,
            unsigned int err)
{
    int                  rv = -ENODEV;
    unsigned long        flags;
    unsigned char        seq;
    unsigned long        seqid;
    struct ipmi_recv_msg *msg = NULL;


    GET_SEQ_FROM_MSGID(msgid, seq, seqid);

    spin_lock_irqsave(&(intf->seq_lock), flags);
    /*
     * We do this verification because the user can be deleted
     * while a message is outstanding.
     */
    if ((intf->seq_table[seq].inuse)
                && (intf->seq_table[seq].seqid == seqid)) {
        struct seq_table *ent = &(intf->seq_table[seq]);

        ent->inuse = 0;
        msg = ent->recv_msg;
        rv = 0;
    }
    spin_unlock_irqrestore(&(intf->seq_lock), flags);

    if (msg)
        deliver_err_response(msg, err);

    return rv;
}


int ipmi_create_user(unsigned int          if_num,
             struct ipmi_user_hndl *handler,
             void                  *handler_data,
             ipmi_user_t           *user)
{
    unsigned long flags;
    ipmi_user_t   new_user;
    int           rv = 0;
    ipmi_smi_t    intf;

    /*
     * There is no module usecount here, because it's not
     * required.  Since this can only be used by and called from
     * other modules, they will implicitly use this module, and
     * thus this can't be removed unless the other modules are
     * removed.
     */

    if (handler == NULL)
        return -EINVAL;

    /*
     * Make sure the driver is actually initialized, this handles
     * problems with initialization order.
     */
    if (!initialized) {
        rv = ipmi_init_msghandler();
        if (rv)
            return rv;

        /*
         * The init code doesn't return an error if it was turned
         * off, but it won't initialize.  Check that.
         */
        if (!initialized)
            return -ENODEV;
    }

    new_user = kmalloc(sizeof(*new_user), GFP_KERNEL);
    if (!new_user)
        return -ENOMEM;

    mutex_lock(&ipmi_interfaces_mutex);
    list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
        if (intf->intf_num == if_num)
            goto found;
    }
    /* Not found, return an error */
    rv = -EINVAL;
    goto out_kfree;

 found:
    /* Note that each existing user holds a refcount to the interface. */
    kref_get(&intf->refcount);

    kref_init(&new_user->refcount);
    new_user->handler = handler;
    new_user->handler_data = handler_data;
    new_user->intf = intf;
    new_user->gets_events = 0;

    if (!try_module_get(intf->handlers->owner)) {
        rv = -ENODEV;
        goto out_kref;
    }

    if (intf->handlers->inc_usecount) {
        rv = intf->handlers->inc_usecount(intf->send_info);
        if (rv) {
            module_put(intf->handlers->owner);
            goto out_kref;
        }
    }

    /*
     * Hold the lock so intf->handlers is guaranteed to be good
     * until now
     */
    mutex_unlock(&ipmi_interfaces_mutex);

    new_user->valid = 1;
    spin_lock_irqsave(&intf->seq_lock, flags);
    list_add_rcu(&new_user->link, &intf->users);
    spin_unlock_irqrestore(&intf->seq_lock, flags);
    *user = new_user;
    return 0;

out_kref:
    kref_put(&intf->refcount, intf_free);
out_kfree:
    mutex_unlock(&ipmi_interfaces_mutex);
    kfree(new_user);
    return rv;
}
EXPORT_SYMBOL(ipmi_create_user);

int ipmi_get_smi_info(int if_num, struct ipmi_smi_info *data)
{
    int           rv = 0;
    ipmi_smi_t    intf;
    struct ipmi_smi_handlers *handlers;

    mutex_lock(&ipmi_interfaces_mutex);
    list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
        if (intf->intf_num == if_num)
            goto found;
    }
    /* Not found, return an error */
    rv = -EINVAL;
    mutex_unlock(&ipmi_interfaces_mutex);
    return rv;

found:
    handlers = intf->handlers;
    rv = -ENOSYS;
    if (handlers->get_smi_info)
        rv = handlers->get_smi_info(intf->send_info, data);
    mutex_unlock(&ipmi_interfaces_mutex);

    return rv;
}
EXPORT_SYMBOL(ipmi_get_smi_info);

static void free_user(struct kref *ref)
{
    ipmi_user_t user = container_of(ref, struct ipmi_user, refcount);
    kfree(user);
}

int ipmi_destroy_user(ipmi_user_t user)
{
    ipmi_smi_t       intf = user->intf;
    int              i;
    unsigned long    flags;
    struct cmd_rcvr  *rcvr;
    struct cmd_rcvr  *rcvrs = NULL;

    user->valid = 0;

    /* Remove the user from the interface's sequence table. */
    spin_lock_irqsave(&intf->seq_lock, flags);
    list_del_rcu(&user->link);

    for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++) {
        if (intf->seq_table[i].inuse
            && (intf->seq_table[i].recv_msg->user == user)) {
            intf->seq_table[i].inuse = 0;
            ipmi_free_recv_msg(intf->seq_table[i].recv_msg);
        }
    }
    spin_unlock_irqrestore(&intf->seq_lock, flags);

    /*
     * Remove the user from the command receiver's table.  First
     * we build a list of everything (not using the standard link,
     * since other things may be using it till we do
     * synchronize_rcu()) then free everything in that list.
     */
    mutex_lock(&intf->cmd_rcvrs_mutex);
    list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {
        if (rcvr->user == user) {
            list_del_rcu(&rcvr->link);
            rcvr->next = rcvrs;
            rcvrs = rcvr;
        }
    }
    mutex_unlock(&intf->cmd_rcvrs_mutex);
    synchronize_rcu();
    while (rcvrs) {
        rcvr = rcvrs;
        rcvrs = rcvr->next;
        kfree(rcvr);
    }

    mutex_lock(&ipmi_interfaces_mutex);
    if (intf->handlers) {
        module_put(intf->handlers->owner);
        if (intf->handlers->dec_usecount)
            intf->handlers->dec_usecount(intf->send_info);
    }
    mutex_unlock(&ipmi_interfaces_mutex);

    kref_put(&intf->refcount, intf_free);

    kref_put(&user->refcount, free_user);

    return 0;
}
EXPORT_SYMBOL(ipmi_destroy_user);

void ipmi_get_version(ipmi_user_t   user,
              unsigned char *major,
              unsigned char *minor)
{
    *major = user->intf->ipmi_version_major;
    *minor = user->intf->ipmi_version_minor;
}
EXPORT_SYMBOL(ipmi_get_version);

int ipmi_set_my_address(ipmi_user_t   user,
            unsigned int  channel,
            unsigned char address)
{
    if (channel >= IPMI_MAX_CHANNELS)
        return -EINVAL;
    user->intf->channels[channel].address = address;
    return 0;
}
EXPORT_SYMBOL(ipmi_set_my_address);

int ipmi_get_my_address(ipmi_user_t   user,
            unsigned int  channel,
            unsigned char *address)
{
    if (channel >= IPMI_MAX_CHANNELS)
        return -EINVAL;
    *address = user->intf->channels[channel].address;
    return 0;
}
EXPORT_SYMBOL(ipmi_get_my_address);

int ipmi_set_my_LUN(ipmi_user_t   user,
            unsigned int  channel,
            unsigned char LUN)
{
    if (channel >= IPMI_MAX_CHANNELS)
        return -EINVAL;
    user->intf->channels[channel].lun = LUN & 0x3;
    return 0;
}
EXPORT_SYMBOL(ipmi_set_my_LUN);

int ipmi_get_my_LUN(ipmi_user_t   user,
            unsigned int  channel,
            unsigned char *address)
{
    if (channel >= IPMI_MAX_CHANNELS)
        return -EINVAL;
    *address = user->intf->channels[channel].lun;
    return 0;
}
EXPORT_SYMBOL(ipmi_get_my_LUN);

int ipmi_get_maintenance_mode(ipmi_user_t user)
{
    int           mode;
    unsigned long flags;

    spin_lock_irqsave(&user->intf->maintenance_mode_lock, flags);
    mode = user->intf->maintenance_mode;
    spin_unlock_irqrestore(&user->intf->maintenance_mode_lock, flags);

    return mode;
}
EXPORT_SYMBOL(ipmi_get_maintenance_mode);

static void maintenance_mode_update(ipmi_smi_t intf)
{
    if (intf->handlers->set_maintenance_mode)
        intf->handlers->set_maintenance_mode(
            intf->send_info, intf->maintenance_mode_enable);
}

int ipmi_set_maintenance_mode(ipmi_user_t user, int mode)
{
    int           rv = 0;
    unsigned long flags;
    ipmi_smi_t    intf = user->intf;

    spin_lock_irqsave(&intf->maintenance_mode_lock, flags);
    if (intf->maintenance_mode != mode) {
        switch (mode) {
        case IPMI_MAINTENANCE_MODE_AUTO:
            intf->maintenance_mode = mode;
            intf->maintenance_mode_enable
                = (intf->auto_maintenance_timeout > 0);
            break;

        case IPMI_MAINTENANCE_MODE_OFF:
            intf->maintenance_mode = mode;
            intf->maintenance_mode_enable = 0;
            break;

        case IPMI_MAINTENANCE_MODE_ON:
            intf->maintenance_mode = mode;
            intf->maintenance_mode_enable = 1;
            break;

        default:
            rv = -EINVAL;
            goto out_unlock;
        }

        maintenance_mode_update(intf);
    }
 out_unlock:
    spin_unlock_irqrestore(&intf->maintenance_mode_lock, flags);

    return rv;
}
EXPORT_SYMBOL(ipmi_set_maintenance_mode);

int ipmi_set_gets_events(ipmi_user_t user, int val)
{
    unsigned long        flags;
    ipmi_smi_t           intf = user->intf;
    struct ipmi_recv_msg *msg, *msg2;
    struct list_head     msgs;

    INIT_LIST_HEAD(&msgs);

    spin_lock_irqsave(&intf->events_lock, flags);
    user->gets_events = val;

    if (intf->delivering_events)
        /*
         * Another thread is delivering events for this, so
         * let it handle any new events.
         */
        goto out;

    /* Deliver any queued events. */
    while (user->gets_events && !list_empty(&intf->waiting_events)) {
        list_for_each_entry_safe(msg, msg2, &intf->waiting_events, link)
            list_move_tail(&msg->link, &msgs);
        intf->waiting_events_count = 0;
        if (intf->event_msg_printed) {
            printk(KERN_WARNING PFX "Event queue no longer"
                   " full\n");
            intf->event_msg_printed = 0;
        }

        intf->delivering_events = 1;
        spin_unlock_irqrestore(&intf->events_lock, flags);

        list_for_each_entry_safe(msg, msg2, &msgs, link) {
            msg->user = user;
            kref_get(&user->refcount);
            deliver_response(msg);
        }

        spin_lock_irqsave(&intf->events_lock, flags);
        intf->delivering_events = 0;
    }

 out:
    spin_unlock_irqrestore(&intf->events_lock, flags);

    return 0;
}
EXPORT_SYMBOL(ipmi_set_gets_events);

static struct cmd_rcvr *find_cmd_rcvr(ipmi_smi_t    intf,
                      unsigned char netfn,
                      unsigned char cmd,
                      unsigned char chan)
{
    struct cmd_rcvr *rcvr;

    list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {
        if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd)
                    && (rcvr->chans & (1 << chan)))
            return rcvr;
    }
    return NULL;
}

static int is_cmd_rcvr_exclusive(ipmi_smi_t    intf,
                 unsigned char netfn,
                 unsigned char cmd,
                 unsigned int  chans)
{
    struct cmd_rcvr *rcvr;

    list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {
        if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd)
                    && (rcvr->chans & chans))
            return 0;
    }
    return 1;
}

int ipmi_register_for_cmd(ipmi_user_t   user,
              unsigned char netfn,
              unsigned char cmd,
              unsigned int  chans)
{
    ipmi_smi_t      intf = user->intf;
    struct cmd_rcvr *rcvr;
    int             rv = 0;


    rcvr = kmalloc(sizeof(*rcvr), GFP_KERNEL);
    if (!rcvr)
        return -ENOMEM;
    rcvr->cmd = cmd;
    rcvr->netfn = netfn;
    rcvr->chans = chans;
    rcvr->user = user;

    mutex_lock(&intf->cmd_rcvrs_mutex);
    /* Make sure the command/netfn is not already registered. */
    if (!is_cmd_rcvr_exclusive(intf, netfn, cmd, chans)) {
        rv = -EBUSY;
        goto out_unlock;
    }

    list_add_rcu(&rcvr->link, &intf->cmd_rcvrs);

 out_unlock:
    mutex_unlock(&intf->cmd_rcvrs_mutex);
    if (rv)
        kfree(rcvr);

    return rv;
}
EXPORT_SYMBOL(ipmi_register_for_cmd);

int ipmi_unregister_for_cmd(ipmi_user_t   user,
                unsigned char netfn,
                unsigned char cmd,
                unsigned int  chans)
{
    ipmi_smi_t      intf = user->intf;
    struct cmd_rcvr *rcvr;
    struct cmd_rcvr *rcvrs = NULL;
    int i, rv = -ENOENT;

    mutex_lock(&intf->cmd_rcvrs_mutex);
    for (i = 0; i < IPMI_NUM_CHANNELS; i++) {
        if (((1 << i) & chans) == 0)
            continue;
        rcvr = find_cmd_rcvr(intf, netfn, cmd, i);
        if (rcvr == NULL)
            continue;
        if (rcvr->user == user) {
            rv = 0;
            rcvr->chans &= ~chans;
            if (rcvr->chans == 0) {
                list_del_rcu(&rcvr->link);
                rcvr->next = rcvrs;
                rcvrs = rcvr;
            }
        }
    }
    mutex_unlock(&intf->cmd_rcvrs_mutex);
    synchronize_rcu();
    while (rcvrs) {
        rcvr = rcvrs;
        rcvrs = rcvr->next;
        kfree(rcvr);
    }
    return rv;
}
EXPORT_SYMBOL(ipmi_unregister_for_cmd);

static unsigned char
ipmb_checksum(unsigned char *data, int size)
{
    unsigned char csum = 0;

    for (; size > 0; size--, data++)
        csum += *data;

    return -csum;
}

static inline void format_ipmb_msg(struct ipmi_smi_msg   *smi_msg,
                   struct kernel_ipmi_msg *msg,
                   struct ipmi_ipmb_addr *ipmb_addr,
                   long                  msgid,
                   unsigned char         ipmb_seq,
                   int                   broadcast,
                   unsigned char         source_address,
                   unsigned char         source_lun)
{
    int i = broadcast;

    /* Format the IPMB header data. */
    smi_msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
    smi_msg->data[1] = IPMI_SEND_MSG_CMD;
    smi_msg->data[2] = ipmb_addr->channel;
    if (broadcast)
        smi_msg->data[3] = 0;
    smi_msg->data[i+3] = ipmb_addr->slave_addr;
    smi_msg->data[i+4] = (msg->netfn << 2) | (ipmb_addr->lun & 0x3);
    smi_msg->data[i+5] = ipmb_checksum(&(smi_msg->data[i+3]), 2);
    smi_msg->data[i+6] = source_address;
    smi_msg->data[i+7] = (ipmb_seq << 2) | source_lun;
    smi_msg->data[i+8] = msg->cmd;

    /* Now tack on the data to the message. */
    if (msg->data_len > 0)
        memcpy(&(smi_msg->data[i+9]), msg->data,
               msg->data_len);
    smi_msg->data_size = msg->data_len + 9;

    /* Now calculate the checksum and tack it on. */
    smi_msg->data[i+smi_msg->data_size]
        = ipmb_checksum(&(smi_msg->data[i+6]),
                smi_msg->data_size-6);

    /*
     * Add on the checksum size and the offset from the
     * broadcast.
     */
    smi_msg->data_size += 1 + i;

    smi_msg->msgid = msgid;
}

static inline void format_lan_msg(struct ipmi_smi_msg   *smi_msg,
                  struct kernel_ipmi_msg *msg,
                  struct ipmi_lan_addr  *lan_addr,
                  long                  msgid,
                  unsigned char         ipmb_seq,
                  unsigned char         source_lun)
{
    /* Format the IPMB header data. */
    smi_msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
    smi_msg->data[1] = IPMI_SEND_MSG_CMD;
    smi_msg->data[2] = lan_addr->channel;
    smi_msg->data[3] = lan_addr->session_handle;
    smi_msg->data[4] = lan_addr->remote_SWID;
    smi_msg->data[5] = (msg->netfn << 2) | (lan_addr->lun & 0x3);
    smi_msg->data[6] = ipmb_checksum(&(smi_msg->data[4]), 2);
    smi_msg->data[7] = lan_addr->local_SWID;
    smi_msg->data[8] = (ipmb_seq << 2) | source_lun;
    smi_msg->data[9] = msg->cmd;

    /* Now tack on the data to the message. */
    if (msg->data_len > 0)
        memcpy(&(smi_msg->data[10]), msg->data,
               msg->data_len);
    smi_msg->data_size = msg->data_len + 10;

    /* Now calculate the checksum and tack it on. */
    smi_msg->data[smi_msg->data_size]
        = ipmb_checksum(&(smi_msg->data[7]),
                smi_msg->data_size-7);

    /*
     * Add on the checksum size and the offset from the
     * broadcast.
     */
    smi_msg->data_size += 1;

    smi_msg->msgid = msgid;
}

/*
 * Separate from ipmi_request so that the user does not have to be
 * supplied in certain circumstances (mainly at panic time).  If
 * messages are supplied, they will be freed, even if an error
 * occurs.
 */
static int i_ipmi_request(ipmi_user_t          user,
              ipmi_smi_t           intf,
              struct ipmi_addr     *addr,
              long                 msgid,
              struct kernel_ipmi_msg *msg,
              void                 *user_msg_data,
              void                 *supplied_smi,
              struct ipmi_recv_msg *supplied_recv,
              int                  priority,
              unsigned char        source_address,
              unsigned char        source_lun,
              int                  retries,
              unsigned int         retry_time_ms)
{
    int                      rv = 0;
    struct ipmi_smi_msg      *smi_msg;
    struct ipmi_recv_msg     *recv_msg;
    unsigned long            flags;
    struct ipmi_smi_handlers *handlers;


    if (supplied_recv)
        recv_msg = supplied_recv;
    else {
        recv_msg = ipmi_alloc_recv_msg();
        if (recv_msg == NULL)
            return -ENOMEM;
    }
    recv_msg->user_msg_data = user_msg_data;

    if (supplied_smi)
        smi_msg = (struct ipmi_smi_msg *) supplied_smi;
    else {
        smi_msg = ipmi_alloc_smi_msg();
        if (smi_msg == NULL) {
            ipmi_free_recv_msg(recv_msg);
            return -ENOMEM;
        }
    }

    rcu_read_lock();
    handlers = intf->handlers;
    if (!handlers) {
        rv = -ENODEV;
        goto out_err;
    }

    recv_msg->user = user;
    if (user)
        kref_get(&user->refcount);
    recv_msg->msgid = msgid;
    /*
     * Store the message to send in the receive message so timeout
     * responses can get the proper response data.
     */
    recv_msg->msg = *msg;

    if (addr->addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE) {
        struct ipmi_system_interface_addr *smi_addr;

        if (msg->netfn & 1) {
            /* Responses are not allowed to the SMI. */
            rv = -EINVAL;
            goto out_err;
        }

        smi_addr = (struct ipmi_system_interface_addr *) addr;
        if (smi_addr->lun > 3) {
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EINVAL;
            goto out_err;
        }

        memcpy(&recv_msg->addr, smi_addr, sizeof(*smi_addr));

        if ((msg->netfn == IPMI_NETFN_APP_REQUEST)
            && ((msg->cmd == IPMI_SEND_MSG_CMD)
            || (msg->cmd == IPMI_GET_MSG_CMD)
            || (msg->cmd == IPMI_READ_EVENT_MSG_BUFFER_CMD))) {
            /*
             * We don't let the user do these, since we manage
             * the sequence numbers.
             */
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EINVAL;
            goto out_err;
        }

        if (((msg->netfn == IPMI_NETFN_APP_REQUEST)
              && ((msg->cmd == IPMI_COLD_RESET_CMD)
              || (msg->cmd == IPMI_WARM_RESET_CMD)))
             || (msg->netfn == IPMI_NETFN_FIRMWARE_REQUEST)) {
            spin_lock_irqsave(&intf->maintenance_mode_lock, flags);
            intf->auto_maintenance_timeout
                = IPMI_MAINTENANCE_MODE_TIMEOUT;
            if (!intf->maintenance_mode
                && !intf->maintenance_mode_enable) {
                intf->maintenance_mode_enable = 1;
                maintenance_mode_update(intf);
            }
            spin_unlock_irqrestore(&intf->maintenance_mode_lock,
                           flags);
        }

        if ((msg->data_len + 2) > IPMI_MAX_MSG_LENGTH) {
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EMSGSIZE;
            goto out_err;
        }

        smi_msg->data[0] = (msg->netfn << 2) | (smi_addr->lun & 0x3);
        smi_msg->data[1] = msg->cmd;
        smi_msg->msgid = msgid;
        smi_msg->user_data = recv_msg;
        if (msg->data_len > 0)
            memcpy(&(smi_msg->data[2]), msg->data, msg->data_len);
        smi_msg->data_size = msg->data_len + 2;
        ipmi_inc_stat(intf, sent_local_commands);
    } else if (is_ipmb_addr(addr) || is_ipmb_bcast_addr(addr)) {
        struct ipmi_ipmb_addr *ipmb_addr;
        unsigned char         ipmb_seq;
        long                  seqid;
        int                   broadcast = 0;

        if (addr->channel >= IPMI_MAX_CHANNELS) {
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EINVAL;
            goto out_err;
        }

        if (intf->channels[addr->channel].medium
                    != IPMI_CHANNEL_MEDIUM_IPMB) {
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EINVAL;
            goto out_err;
        }

        if (retries < 0) {
            if (addr->addr_type == IPMI_IPMB_BROADCAST_ADDR_TYPE)
            retries = 0; /* Don't retry broadcasts. */
            else
            retries = 4;
        }
        if (addr->addr_type == IPMI_IPMB_BROADCAST_ADDR_TYPE) {
            /*
             * Broadcasts add a zero at the beginning of the
             * message, but otherwise is the same as an IPMB
             * address.
             */
            addr->addr_type = IPMI_IPMB_ADDR_TYPE;
            broadcast = 1;
        }


        /* Default to 1 second retries. */
        if (retry_time_ms == 0)
            retry_time_ms = 1000;

        /*
         * 9 for the header and 1 for the checksum, plus
         * possibly one for the broadcast.
         */
        if ((msg->data_len + 10 + broadcast) > IPMI_MAX_MSG_LENGTH) {
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EMSGSIZE;
            goto out_err;
        }

        ipmb_addr = (struct ipmi_ipmb_addr *) addr;
        if (ipmb_addr->lun > 3) {
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EINVAL;
            goto out_err;
        }

        memcpy(&recv_msg->addr, ipmb_addr, sizeof(*ipmb_addr));

        if (recv_msg->msg.netfn & 0x1) {
            /*
             * It's a response, so use the user's sequence
             * from msgid.
             */
            ipmi_inc_stat(intf, sent_ipmb_responses);
            format_ipmb_msg(smi_msg, msg, ipmb_addr, msgid,
                    msgid, broadcast,
                    source_address, source_lun);

            /*
             * Save the receive message so we can use it
             * to deliver the response.
             */
            smi_msg->user_data = recv_msg;
        } else {
            /* It's a command, so get a sequence for it. */

            spin_lock_irqsave(&(intf->seq_lock), flags);

            /*
             * Create a sequence number with a 1 second
             * timeout and 4 retries.
             */
            rv = intf_next_seq(intf,
                       recv_msg,
                       retry_time_ms,
                       retries,
                       broadcast,
                       &ipmb_seq,
                       &seqid);
            if (rv) {
                /*
                 * We have used up all the sequence numbers,
                 * probably, so abort.
                 */
                spin_unlock_irqrestore(&(intf->seq_lock),
                               flags);
                goto out_err;
            }

            ipmi_inc_stat(intf, sent_ipmb_commands);

            /*
             * Store the sequence number in the message,
             * so that when the send message response
             * comes back we can start the timer.
             */
            format_ipmb_msg(smi_msg, msg, ipmb_addr,
                    STORE_SEQ_IN_MSGID(ipmb_seq, seqid),
                    ipmb_seq, broadcast,
                    source_address, source_lun);

            /*
             * Copy the message into the recv message data, so we
             * can retransmit it later if necessary.
             */
            memcpy(recv_msg->msg_data, smi_msg->data,
                   smi_msg->data_size);
            recv_msg->msg.data = recv_msg->msg_data;
            recv_msg->msg.data_len = smi_msg->data_size;

            /*
             * We don't unlock until here, because we need
             * to copy the completed message into the
             * recv_msg before we release the lock.
             * Otherwise, race conditions may bite us.  I
             * know that's pretty paranoid, but I prefer
             * to be correct.
             */
            spin_unlock_irqrestore(&(intf->seq_lock), flags);
        }
    } else if (is_lan_addr(addr)) {
        struct ipmi_lan_addr  *lan_addr;
        unsigned char         ipmb_seq;
        long                  seqid;

        if (addr->channel >= IPMI_MAX_CHANNELS) {
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EINVAL;
            goto out_err;
        }

        if ((intf->channels[addr->channel].medium
                != IPMI_CHANNEL_MEDIUM_8023LAN)
            && (intf->channels[addr->channel].medium
                != IPMI_CHANNEL_MEDIUM_ASYNC)) {
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EINVAL;
            goto out_err;
        }

        retries = 4;

        /* Default to 1 second retries. */
        if (retry_time_ms == 0)
            retry_time_ms = 1000;

        /* 11 for the header and 1 for the checksum. */
        if ((msg->data_len + 12) > IPMI_MAX_MSG_LENGTH) {
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EMSGSIZE;
            goto out_err;
        }

        lan_addr = (struct ipmi_lan_addr *) addr;
        if (lan_addr->lun > 3) {
            ipmi_inc_stat(intf, sent_invalid_commands);
            rv = -EINVAL;
            goto out_err;
        }

        memcpy(&recv_msg->addr, lan_addr, sizeof(*lan_addr));

        if (recv_msg->msg.netfn & 0x1) {
            /*
             * It's a response, so use the user's sequence
             * from msgid.
             */
            ipmi_inc_stat(intf, sent_lan_responses);
            format_lan_msg(smi_msg, msg, lan_addr, msgid,
                       msgid, source_lun);

            /*
             * Save the receive message so we can use it
             * to deliver the response.
             */
            smi_msg->user_data = recv_msg;
        } else {
            /* It's a command, so get a sequence for it. */

            spin_lock_irqsave(&(intf->seq_lock), flags);

            /*
             * Create a sequence number with a 1 second
             * timeout and 4 retries.
             */
            rv = intf_next_seq(intf,
                       recv_msg,
                       retry_time_ms,
                       retries,
                       0,
                       &ipmb_seq,
                       &seqid);
            if (rv) {
                /*
                 * We have used up all the sequence numbers,
                 * probably, so abort.
                 */
                spin_unlock_irqrestore(&(intf->seq_lock),
                               flags);
                goto out_err;
            }

            ipmi_inc_stat(intf, sent_lan_commands);

            /*
             * Store the sequence number in the message,
             * so that when the send message response
             * comes back we can start the timer.
             */
            format_lan_msg(smi_msg, msg, lan_addr,
                       STORE_SEQ_IN_MSGID(ipmb_seq, seqid),
                       ipmb_seq, source_lun);

            /*
             * Copy the message into the recv message data, so we
             * can retransmit it later if necessary.
             */
            memcpy(recv_msg->msg_data, smi_msg->data,
                   smi_msg->data_size);
            recv_msg->msg.data = recv_msg->msg_data;
            recv_msg->msg.data_len = smi_msg->data_size;

            /*
             * We don't unlock until here, because we need
             * to copy the completed message into the
             * recv_msg before we release the lock.
             * Otherwise, race conditions may bite us.  I
             * know that's pretty paranoid, but I prefer
             * to be correct.
             */
            spin_unlock_irqrestore(&(intf->seq_lock), flags);
        }
    } else {
        /* Unknown address type. */
        ipmi_inc_stat(intf, sent_invalid_commands);
        rv = -EINVAL;
        goto out_err;
    }

#ifdef DEBUG_MSGING
    {
        int m;
        for (m = 0; m < smi_msg->data_size; m++)
            printk(" %2.2x", smi_msg->data[m]);
        printk("\n");
    }
#endif

    handlers->sender(intf->send_info, smi_msg, priority);
    rcu_read_unlock();

    return 0;

 out_err:
    rcu_read_unlock();
    ipmi_free_smi_msg(smi_msg);
    ipmi_free_recv_msg(recv_msg);
    return rv;
}

static int check_addr(ipmi_smi_t       intf,
              struct ipmi_addr *addr,
              unsigned char    *saddr,
              unsigned char    *lun)
{
    if (addr->channel >= IPMI_MAX_CHANNELS)
        return -EINVAL;
    *lun = intf->channels[addr->channel].lun;
    *saddr = intf->channels[addr->channel].address;
    return 0;
}

int ipmi_request_settime(ipmi_user_t      user,
             struct ipmi_addr *addr,
             long             msgid,
             struct kernel_ipmi_msg  *msg,
             void             *user_msg_data,
             int              priority,
             int              retries,
             unsigned int     retry_time_ms)
{
    unsigned char saddr, lun;
    int           rv;

    if (!user)
        return -EINVAL;
    rv = check_addr(user->intf, addr, &saddr, &lun);
    if (rv)
        return rv;
    return i_ipmi_request(user,
                  user->intf,
                  addr,
                  msgid,
                  msg,
                  user_msg_data,
                  NULL, NULL,
                  priority,
                  saddr,
                  lun,
                  retries,
                  retry_time_ms);
}
EXPORT_SYMBOL(ipmi_request_settime);

int ipmi_request_supply_msgs(ipmi_user_t          user,
                 struct ipmi_addr     *addr,
                 long                 msgid,
                 struct kernel_ipmi_msg *msg,
                 void                 *user_msg_data,
                 void                 *supplied_smi,
                 struct ipmi_recv_msg *supplied_recv,
                 int                  priority)
{
    unsigned char saddr = 0, lun = 0;
    int           rv;

    if (!user)
        return -EINVAL;
    rv = check_addr(user->intf, addr, &saddr, &lun);
    if (rv)
        return rv;
    return i_ipmi_request(user,
                  user->intf,
                  addr,
                  msgid,
                  msg,
                  user_msg_data,
                  supplied_smi,
                  supplied_recv,
                  priority,
                  saddr,
                  lun,
                  -1, 0);
}
EXPORT_SYMBOL(ipmi_request_supply_msgs);

#ifdef CONFIG_PROC_FS
static int smi_ipmb_proc_show(struct seq_file *m, void *v)
{
    ipmi_smi_t intf = m->private;
    int        i;

    seq_printf(m, "%x", intf->channels[0].address);
    for (i = 1; i < IPMI_MAX_CHANNELS; i++)
        seq_printf(m, " %x", intf->channels[i].address);
    return seq_putc(m, '\n');
}

static int smi_ipmb_proc_open(struct inode *inode, struct file *file)
{
    return single_open(file, smi_ipmb_proc_show, PDE(inode)->data);
}

static const struct file_operations smi_ipmb_proc_ops = {
    .open       = smi_ipmb_proc_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static int smi_version_proc_show(struct seq_file *m, void *v)
{
    ipmi_smi_t intf = m->private;

    return seq_printf(m, "%u.%u\n",
               ipmi_version_major(&intf->bmc->id),
               ipmi_version_minor(&intf->bmc->id));
}

static int smi_version_proc_open(struct inode *inode, struct file *file)
{
    return single_open(file, smi_version_proc_show, PDE(inode)->data);
}

static const struct file_operations smi_version_proc_ops = {
    .open       = smi_version_proc_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static int smi_stats_proc_show(struct seq_file *m, void *v)
{
    ipmi_smi_t intf = m->private;

    seq_printf(m, "sent_invalid_commands:       %u\n",
               ipmi_get_stat(intf, sent_invalid_commands));
    seq_printf(m, "sent_local_commands:         %u\n",
               ipmi_get_stat(intf, sent_local_commands));
    seq_printf(m, "handled_local_responses:     %u\n",
               ipmi_get_stat(intf, handled_local_responses));
    seq_printf(m, "unhandled_local_responses:   %u\n",
               ipmi_get_stat(intf, unhandled_local_responses));
    seq_printf(m, "sent_ipmb_commands:          %u\n",
               ipmi_get_stat(intf, sent_ipmb_commands));
    seq_printf(m, "sent_ipmb_command_errs:      %u\n",
               ipmi_get_stat(intf, sent_ipmb_command_errs));
    seq_printf(m, "retransmitted_ipmb_commands: %u\n",
               ipmi_get_stat(intf, retransmitted_ipmb_commands));
    seq_printf(m, "timed_out_ipmb_commands:     %u\n",
               ipmi_get_stat(intf, timed_out_ipmb_commands));
    seq_printf(m, "timed_out_ipmb_broadcasts:   %u\n",
               ipmi_get_stat(intf, timed_out_ipmb_broadcasts));
    seq_printf(m, "sent_ipmb_responses:         %u\n",
               ipmi_get_stat(intf, sent_ipmb_responses));
    seq_printf(m, "handled_ipmb_responses:      %u\n",
               ipmi_get_stat(intf, handled_ipmb_responses));
    seq_printf(m, "invalid_ipmb_responses:      %u\n",
               ipmi_get_stat(intf, invalid_ipmb_responses));
    seq_printf(m, "unhandled_ipmb_responses:    %u\n",
               ipmi_get_stat(intf, unhandled_ipmb_responses));
    seq_printf(m, "sent_lan_commands:           %u\n",
               ipmi_get_stat(intf, sent_lan_commands));
    seq_printf(m, "sent_lan_command_errs:       %u\n",
               ipmi_get_stat(intf, sent_lan_command_errs));
    seq_printf(m, "retransmitted_lan_commands:  %u\n",
               ipmi_get_stat(intf, retransmitted_lan_commands));
    seq_printf(m, "timed_out_lan_commands:      %u\n",
               ipmi_get_stat(intf, timed_out_lan_commands));
    seq_printf(m, "sent_lan_responses:          %u\n",
               ipmi_get_stat(intf, sent_lan_responses));
    seq_printf(m, "handled_lan_responses:       %u\n",
               ipmi_get_stat(intf, handled_lan_responses));
    seq_printf(m, "invalid_lan_responses:       %u\n",
               ipmi_get_stat(intf, invalid_lan_responses));
    seq_printf(m, "unhandled_lan_responses:     %u\n",
               ipmi_get_stat(intf, unhandled_lan_responses));
    seq_printf(m, "handled_commands:            %u\n",
               ipmi_get_stat(intf, handled_commands));
    seq_printf(m, "invalid_commands:            %u\n",
               ipmi_get_stat(intf, invalid_commands));
    seq_printf(m, "unhandled_commands:          %u\n",
               ipmi_get_stat(intf, unhandled_commands));
    seq_printf(m, "invalid_events:              %u\n",
               ipmi_get_stat(intf, invalid_events));
    seq_printf(m, "events:                      %u\n",
               ipmi_get_stat(intf, events));
    seq_printf(m, "failed rexmit LAN msgs:      %u\n",
               ipmi_get_stat(intf, dropped_rexmit_lan_commands));
    seq_printf(m, "failed rexmit IPMB msgs:     %u\n",
               ipmi_get_stat(intf, dropped_rexmit_ipmb_commands));
    return 0;
}

static int smi_stats_proc_open(struct inode *inode, struct file *file)
{
    return single_open(file, smi_stats_proc_show, PDE(inode)->data);
}

static const struct file_operations smi_stats_proc_ops = {
    .open       = smi_stats_proc_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};
#endif /* CONFIG_PROC_FS */

int ipmi_smi_add_proc_entry(ipmi_smi_t smi, char *name,
                const struct file_operations *proc_ops,
                void *data)
{
    int                    rv = 0;
#ifdef CONFIG_PROC_FS
    struct proc_dir_entry  *file;
    struct ipmi_proc_entry *entry;

    /* Create a list element. */
    entry = kmalloc(sizeof(*entry), GFP_KERNEL);
    if (!entry)
        return -ENOMEM;
    entry->name = kmalloc(strlen(name)+1, GFP_KERNEL);
    if (!entry->name) {
        kfree(entry);
        return -ENOMEM;
    }
    strcpy(entry->name, name);

    file = proc_create_data(name, 0, smi->proc_dir, proc_ops, data);
    if (!file) {
        kfree(entry->name);
        kfree(entry);
        rv = -ENOMEM;
    } else {
        mutex_lock(&smi->proc_entry_lock);
        /* Stick it on the list. */
        entry->next = smi->proc_entries;
        smi->proc_entries = entry;
        mutex_unlock(&smi->proc_entry_lock);
    }
#endif /* CONFIG_PROC_FS */

    return rv;
}
EXPORT_SYMBOL(ipmi_smi_add_proc_entry);

static int add_proc_entries(ipmi_smi_t smi, int num)
{
    int rv = 0;

#ifdef CONFIG_PROC_FS
    sprintf(smi->proc_dir_name, "%d", num);
    smi->proc_dir = proc_mkdir(smi->proc_dir_name, proc_ipmi_root);
    if (!smi->proc_dir)
        rv = -ENOMEM;

    if (rv == 0)
        rv = ipmi_smi_add_proc_entry(smi, "stats",
                         &smi_stats_proc_ops,
                         smi);

    if (rv == 0)
        rv = ipmi_smi_add_proc_entry(smi, "ipmb",
                         &smi_ipmb_proc_ops,
                         smi);

    if (rv == 0)
        rv = ipmi_smi_add_proc_entry(smi, "version",
                         &smi_version_proc_ops,
                         smi);
#endif /* CONFIG_PROC_FS */

    return rv;
}

static void remove_proc_entries(ipmi_smi_t smi)
{
#ifdef CONFIG_PROC_FS
    struct ipmi_proc_entry *entry;

    mutex_lock(&smi->proc_entry_lock);
    while (smi->proc_entries) {
        entry = smi->proc_entries;
        smi->proc_entries = entry->next;

        remove_proc_entry(entry->name, smi->proc_dir);
        kfree(entry->name);
        kfree(entry);
    }
    mutex_unlock(&smi->proc_entry_lock);
    remove_proc_entry(smi->proc_dir_name, proc_ipmi_root);
#endif /* CONFIG_PROC_FS */
}

static int __find_bmc_guid(struct device *dev, void *data)
{
    unsigned char *id = data;
    struct bmc_device *bmc = dev_get_drvdata(dev);
    return memcmp(bmc->guid, id, 16) == 0;
}

static struct bmc_device *ipmi_find_bmc_guid(struct device_driver *drv,
                         unsigned char *guid)
{
    struct device *dev;

    dev = driver_find_device(drv, NULL, guid, __find_bmc_guid);
    if (dev)
        return dev_get_drvdata(dev);
    else
        return NULL;
}

struct prod_dev_id {
    unsigned int  product_id;
    unsigned char device_id;
};

static int __find_bmc_prod_dev_id(struct device *dev, void *data)
{
    struct prod_dev_id *id = data;
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return (bmc->id.product_id == id->product_id
        && bmc->id.device_id == id->device_id);
}

static struct bmc_device *ipmi_find_bmc_prod_dev_id(
    struct device_driver *drv,
    unsigned int product_id, unsigned char device_id)
{
    struct prod_dev_id id = {
        .product_id = product_id,
        .device_id = device_id,
    };
    struct device *dev;

    dev = driver_find_device(drv, NULL, &id, __find_bmc_prod_dev_id);
    if (dev)
        return dev_get_drvdata(dev);
    else
        return NULL;
}

static ssize_t device_id_show(struct device *dev,
                  struct device_attribute *attr,
                  char *buf)
{
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return snprintf(buf, 10, "%u\n", bmc->id.device_id);
}

static ssize_t provides_dev_sdrs_show(struct device *dev,
                      struct device_attribute *attr,
                      char *buf)
{
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return snprintf(buf, 10, "%u\n",
            (bmc->id.device_revision & 0x80) >> 7);
}

static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
                 char *buf)
{
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return snprintf(buf, 20, "%u\n",
            bmc->id.device_revision & 0x0F);
}

static ssize_t firmware_rev_show(struct device *dev,
                 struct device_attribute *attr,
                 char *buf)
{
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return snprintf(buf, 20, "%u.%x\n", bmc->id.firmware_revision_1,
            bmc->id.firmware_revision_2);
}

static ssize_t ipmi_version_show(struct device *dev,
                 struct device_attribute *attr,
                 char *buf)
{
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return snprintf(buf, 20, "%u.%u\n",
            ipmi_version_major(&bmc->id),
            ipmi_version_minor(&bmc->id));
}

static ssize_t add_dev_support_show(struct device *dev,
                    struct device_attribute *attr,
                    char *buf)
{
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return snprintf(buf, 10, "0x%02x\n",
            bmc->id.additional_device_support);
}

static ssize_t manufacturer_id_show(struct device *dev,
                    struct device_attribute *attr,
                    char *buf)
{
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return snprintf(buf, 20, "0x%6.6x\n", bmc->id.manufacturer_id);
}

static ssize_t product_id_show(struct device *dev,
                   struct device_attribute *attr,
                   char *buf)
{
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return snprintf(buf, 10, "0x%4.4x\n", bmc->id.product_id);
}

static ssize_t aux_firmware_rev_show(struct device *dev,
                     struct device_attribute *attr,
                     char *buf)
{
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return snprintf(buf, 21, "0x%02x 0x%02x 0x%02x 0x%02x\n",
            bmc->id.aux_firmware_revision[3],
            bmc->id.aux_firmware_revision[2],
            bmc->id.aux_firmware_revision[1],
            bmc->id.aux_firmware_revision[0]);
}

static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct bmc_device *bmc = dev_get_drvdata(dev);

    return snprintf(buf, 100, "%Lx%Lx\n",
            (long long) bmc->guid[0],
            (long long) bmc->guid[8]);
}

static void remove_files(struct bmc_device *bmc)
{
    if (!bmc->dev)
        return;

    device_remove_file(&bmc->dev->dev,
               &bmc->device_id_attr);
    device_remove_file(&bmc->dev->dev,
               &bmc->provides_dev_sdrs_attr);
    device_remove_file(&bmc->dev->dev,
               &bmc->revision_attr);
    device_remove_file(&bmc->dev->dev,
               &bmc->firmware_rev_attr);
    device_remove_file(&bmc->dev->dev,
               &bmc->version_attr);
    device_remove_file(&bmc->dev->dev,
               &bmc->add_dev_support_attr);
    device_remove_file(&bmc->dev->dev,
               &bmc->manufacturer_id_attr);
    device_remove_file(&bmc->dev->dev,
               &bmc->product_id_attr);

    if (bmc->id.aux_firmware_revision_set)
        device_remove_file(&bmc->dev->dev,
                   &bmc->aux_firmware_rev_attr);
    if (bmc->guid_set)
        device_remove_file(&bmc->dev->dev,
                   &bmc->guid_attr);
}

static void
cleanup_bmc_device(struct kref *ref)
{
    struct bmc_device *bmc;

    bmc = container_of(ref, struct bmc_device, refcount);

    remove_files(bmc);
    platform_device_unregister(bmc->dev);
    kfree(bmc);
}

static void ipmi_bmc_unregister(ipmi_smi_t intf)
{
    struct bmc_device *bmc = intf->bmc;

    if (intf->sysfs_name) {
        sysfs_remove_link(&intf->si_dev->kobj, intf->sysfs_name);
        kfree(intf->sysfs_name);
        intf->sysfs_name = NULL;
    }
    if (intf->my_dev_name) {
        sysfs_remove_link(&bmc->dev->dev.kobj, intf->my_dev_name);
        kfree(intf->my_dev_name);
        intf->my_dev_name = NULL;
    }

    mutex_lock(&ipmidriver_mutex);
    kref_put(&bmc->refcount, cleanup_bmc_device);
    intf->bmc = NULL;
    mutex_unlock(&ipmidriver_mutex);
}

static int create_files(struct bmc_device *bmc)
{
    int err;

    bmc->device_id_attr.attr.name = "device_id";
    bmc->device_id_attr.attr.mode = S_IRUGO;
    bmc->device_id_attr.show = device_id_show;
    sysfs_attr_init(&bmc->device_id_attr.attr);

    bmc->provides_dev_sdrs_attr.attr.name = "provides_device_sdrs";
    bmc->provides_dev_sdrs_attr.attr.mode = S_IRUGO;
    bmc->provides_dev_sdrs_attr.show = provides_dev_sdrs_show;
    sysfs_attr_init(&bmc->provides_dev_sdrs_attr.attr);

    bmc->revision_attr.attr.name = "revision";
    bmc->revision_attr.attr.mode = S_IRUGO;
    bmc->revision_attr.show = revision_show;
    sysfs_attr_init(&bmc->revision_attr.attr);

    bmc->firmware_rev_attr.attr.name = "firmware_revision";
    bmc->firmware_rev_attr.attr.mode = S_IRUGO;
    bmc->firmware_rev_attr.show = firmware_rev_show;
    sysfs_attr_init(&bmc->firmware_rev_attr.attr);

    bmc->version_attr.attr.name = "ipmi_version";
    bmc->version_attr.attr.mode = S_IRUGO;
    bmc->version_attr.show = ipmi_version_show;
    sysfs_attr_init(&bmc->version_attr.attr);

    bmc->add_dev_support_attr.attr.name = "additional_device_support";
    bmc->add_dev_support_attr.attr.mode = S_IRUGO;
    bmc->add_dev_support_attr.show = add_dev_support_show;
    sysfs_attr_init(&bmc->add_dev_support_attr.attr);

    bmc->manufacturer_id_attr.attr.name = "manufacturer_id";
    bmc->manufacturer_id_attr.attr.mode = S_IRUGO;
    bmc->manufacturer_id_attr.show = manufacturer_id_show;
    sysfs_attr_init(&bmc->manufacturer_id_attr.attr);

    bmc->product_id_attr.attr.name = "product_id";
    bmc->product_id_attr.attr.mode = S_IRUGO;
    bmc->product_id_attr.show = product_id_show;
    sysfs_attr_init(&bmc->product_id_attr.attr);

    bmc->guid_attr.attr.name = "guid";
    bmc->guid_attr.attr.mode = S_IRUGO;
    bmc->guid_attr.show = guid_show;
    sysfs_attr_init(&bmc->guid_attr.attr);

    bmc->aux_firmware_rev_attr.attr.name = "aux_firmware_revision";
    bmc->aux_firmware_rev_attr.attr.mode = S_IRUGO;
    bmc->aux_firmware_rev_attr.show = aux_firmware_rev_show;
    sysfs_attr_init(&bmc->aux_firmware_rev_attr.attr);

    err = device_create_file(&bmc->dev->dev,
               &bmc->device_id_attr);
    if (err)
        goto out;
    err = device_create_file(&bmc->dev->dev,
               &bmc->provides_dev_sdrs_attr);
    if (err)
        goto out_devid;
    err = device_create_file(&bmc->dev->dev,
               &bmc->revision_attr);
    if (err)
        goto out_sdrs;
    err = device_create_file(&bmc->dev->dev,
               &bmc->firmware_rev_attr);
    if (err)
        goto out_rev;
    err = device_create_file(&bmc->dev->dev,
               &bmc->version_attr);
    if (err)
        goto out_firm;
    err = device_create_file(&bmc->dev->dev,
               &bmc->add_dev_support_attr);
    if (err)
        goto out_version;
    err = device_create_file(&bmc->dev->dev,
               &bmc->manufacturer_id_attr);
    if (err)
        goto out_add_dev;
    err = device_create_file(&bmc->dev->dev,
               &bmc->product_id_attr);
    if (err)
        goto out_manu;
    if (bmc->id.aux_firmware_revision_set) {
        err = device_create_file(&bmc->dev->dev,
                   &bmc->aux_firmware_rev_attr);
        if (err)
            goto out_prod_id;
    }
    if (bmc->guid_set) {
        err = device_create_file(&bmc->dev->dev,
                   &bmc->guid_attr);
        if (err)
            goto out_aux_firm;
    }

    return 0;

out_aux_firm:
    if (bmc->id.aux_firmware_revision_set)
        device_remove_file(&bmc->dev->dev,
                   &bmc->aux_firmware_rev_attr);
out_prod_id:
    device_remove_file(&bmc->dev->dev,
               &bmc->product_id_attr);
out_manu:
    device_remove_file(&bmc->dev->dev,
               &bmc->manufacturer_id_attr);
out_add_dev:
    device_remove_file(&bmc->dev->dev,
               &bmc->add_dev_support_attr);
out_version:
    device_remove_file(&bmc->dev->dev,
               &bmc->version_attr);
out_firm:
    device_remove_file(&bmc->dev->dev,
               &bmc->firmware_rev_attr);
out_rev:
    device_remove_file(&bmc->dev->dev,
               &bmc->revision_attr);
out_sdrs:
    device_remove_file(&bmc->dev->dev,
               &bmc->provides_dev_sdrs_attr);
out_devid:
    device_remove_file(&bmc->dev->dev,
               &bmc->device_id_attr);
out:
    return err;
}

static int ipmi_bmc_register(ipmi_smi_t intf, int ifnum,
                 const char *sysfs_name)
{
    int               rv;
    struct bmc_device *bmc = intf->bmc;
    struct bmc_device *old_bmc;
    int               size;
    char              dummy[1];

    mutex_lock(&ipmidriver_mutex);

    /*
     * Try to find if there is an bmc_device struct
     * representing the interfaced BMC already
     */
    if (bmc->guid_set)
        old_bmc = ipmi_find_bmc_guid(&ipmidriver.driver, bmc->guid);
    else
        old_bmc = ipmi_find_bmc_prod_dev_id(&ipmidriver.driver,
                            bmc->id.product_id,
                            bmc->id.device_id);

    /*
     * If there is already an bmc_device, free the new one,
     * otherwise register the new BMC device
     */
    if (old_bmc) {
        kfree(bmc);
        intf->bmc = old_bmc;
        bmc = old_bmc;

        kref_get(&bmc->refcount);
        mutex_unlock(&ipmidriver_mutex);

        printk(KERN_INFO
               "ipmi: interfacing existing BMC (man_id: 0x%6.6x,"
               " prod_id: 0x%4.4x, dev_id: 0x%2.2x)\n",
               bmc->id.manufacturer_id,
               bmc->id.product_id,
               bmc->id.device_id);
    } else {
        char name[14];
        unsigned char orig_dev_id = bmc->id.device_id;
        int warn_printed = 0;

        snprintf(name, sizeof(name),
             "ipmi_bmc.%4.4x", bmc->id.product_id);

        while (ipmi_find_bmc_prod_dev_id(&ipmidriver.driver,
                         bmc->id.product_id,
                         bmc->id.device_id)) {
            if (!warn_printed) {
                printk(KERN_WARNING PFX
                       "This machine has two different BMCs"
                       " with the same product id and device"
                       " id.  This is an error in the"
                       " firmware, but incrementing the"
                       " device id to work around the problem."
                       " Prod ID = 0x%x, Dev ID = 0x%x\n",
                       bmc->id.product_id, bmc->id.device_id);
                warn_printed = 1;
            }
            bmc->id.device_id++; /* Wraps at 255 */
            if (bmc->id.device_id == orig_dev_id) {
                printk(KERN_ERR PFX
                       "Out of device ids!\n");
                break;
            }
        }

        bmc->dev = platform_device_alloc(name, bmc->id.device_id);
        if (!bmc->dev) {
            mutex_unlock(&ipmidriver_mutex);
            printk(KERN_ERR
                   "ipmi_msghandler:"
                   " Unable to allocate platform device\n");
            return -ENOMEM;
        }
        bmc->dev->dev.driver = &ipmidriver.driver;
        dev_set_drvdata(&bmc->dev->dev, bmc);
        kref_init(&bmc->refcount);

        rv = platform_device_add(bmc->dev);
        mutex_unlock(&ipmidriver_mutex);
        if (rv) {
            platform_device_put(bmc->dev);
            bmc->dev = NULL;
            printk(KERN_ERR
                   "ipmi_msghandler:"
                   " Unable to register bmc device: %d\n",
                   rv);
            /*
             * Don't go to out_err, you can only do that if
             * the device is registered already.
             */
            return rv;
        }

        rv = create_files(bmc);
        if (rv) {
            mutex_lock(&ipmidriver_mutex);
            platform_device_unregister(bmc->dev);
            mutex_unlock(&ipmidriver_mutex);

            return rv;
        }

        dev_info(intf->si_dev, "Found new BMC (man_id: 0x%6.6x, "
             "prod_id: 0x%4.4x, dev_id: 0x%2.2x)\n",
             bmc->id.manufacturer_id,
             bmc->id.product_id,
             bmc->id.device_id);
    }

    /*
     * create symlink from system interface device to bmc device
     * and back.
     */
    intf->sysfs_name = kstrdup(sysfs_name, GFP_KERNEL);
    if (!intf->sysfs_name) {
        rv = -ENOMEM;
        printk(KERN_ERR
               "ipmi_msghandler: allocate link to BMC: %d\n",
               rv);
        goto out_err;
    }

    rv = sysfs_create_link(&intf->si_dev->kobj,
                   &bmc->dev->dev.kobj, intf->sysfs_name);
    if (rv) {
        kfree(intf->sysfs_name);
        intf->sysfs_name = NULL;
        printk(KERN_ERR
               "ipmi_msghandler: Unable to create bmc symlink: %d\n",
               rv);
        goto out_err;
    }

    size = snprintf(dummy, 0, "ipmi%d", ifnum);
    intf->my_dev_name = kmalloc(size+1, GFP_KERNEL);
    if (!intf->my_dev_name) {
        kfree(intf->sysfs_name);
        intf->sysfs_name = NULL;
        rv = -ENOMEM;
        printk(KERN_ERR
               "ipmi_msghandler: allocate link from BMC: %d\n",
               rv);
        goto out_err;
    }
    snprintf(intf->my_dev_name, size+1, "ipmi%d", ifnum);

    rv = sysfs_create_link(&bmc->dev->dev.kobj, &intf->si_dev->kobj,
                   intf->my_dev_name);
    if (rv) {
        kfree(intf->sysfs_name);
        intf->sysfs_name = NULL;
        kfree(intf->my_dev_name);
        intf->my_dev_name = NULL;
        printk(KERN_ERR
               "ipmi_msghandler:"
               " Unable to create symlink to bmc: %d\n",
               rv);
        goto out_err;
    }

    return 0;

out_err:
    ipmi_bmc_unregister(intf);
    return rv;
}

static int
send_guid_cmd(ipmi_smi_t intf, int chan)
{
    struct kernel_ipmi_msg            msg;
    struct ipmi_system_interface_addr si;

    si.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
    si.channel = IPMI_BMC_CHANNEL;
    si.lun = 0;

    msg.netfn = IPMI_NETFN_APP_REQUEST;
    msg.cmd = IPMI_GET_DEVICE_GUID_CMD;
    msg.data = NULL;
    msg.data_len = 0;
    return i_ipmi_request(NULL,
                  intf,
                  (struct ipmi_addr *) &si,
                  0,
                  &msg,
                  intf,
                  NULL,
                  NULL,
                  0,
                  intf->channels[0].address,
                  intf->channels[0].lun,
                  -1, 0);
}

static void
guid_handler(ipmi_smi_t intf, struct ipmi_recv_msg *msg)
{
    if ((msg->addr.addr_type != IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
        || (msg->msg.netfn != IPMI_NETFN_APP_RESPONSE)
        || (msg->msg.cmd != IPMI_GET_DEVICE_GUID_CMD))
        /* Not for me */
        return;

    if (msg->msg.data[0] != 0) {
        /* Error from getting the GUID, the BMC doesn't have one. */
        intf->bmc->guid_set = 0;
        goto out;
    }

    if (msg->msg.data_len < 17) {
        intf->bmc->guid_set = 0;
        printk(KERN_WARNING PFX
               "guid_handler: The GUID response from the BMC was too"
               " short, it was %d but should have been 17.  Assuming"
               " GUID is not available.\n",
               msg->msg.data_len);
        goto out;
    }

    memcpy(intf->bmc->guid, msg->msg.data, 16);
    intf->bmc->guid_set = 1;
 out:
    wake_up(&intf->waitq);
}

static void
get_guid(ipmi_smi_t intf)
{
    int rv;

    intf->bmc->guid_set = 0x2;
    intf->null_user_handler = guid_handler;
    rv = send_guid_cmd(intf, 0);
    if (rv)
        /* Send failed, no GUID available. */
        intf->bmc->guid_set = 0;
    wait_event(intf->waitq, intf->bmc->guid_set != 2);
    intf->null_user_handler = NULL;
}

static int
send_channel_info_cmd(ipmi_smi_t intf, int chan)
{
    struct kernel_ipmi_msg            msg;
    unsigned char                     data[1];
    struct ipmi_system_interface_addr si;

    si.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
    si.channel = IPMI_BMC_CHANNEL;
    si.lun = 0;

    msg.netfn = IPMI_NETFN_APP_REQUEST;
    msg.cmd = IPMI_GET_CHANNEL_INFO_CMD;
    msg.data = data;
    msg.data_len = 1;
    data[0] = chan;
    return i_ipmi_request(NULL,
                  intf,
                  (struct ipmi_addr *) &si,
                  0,
                  &msg,
                  intf,
                  NULL,
                  NULL,
                  0,
                  intf->channels[0].address,
                  intf->channels[0].lun,
                  -1, 0);
}

static void
channel_handler(ipmi_smi_t intf, struct ipmi_recv_msg *msg)
{
    int rv = 0;
    int chan;

    if ((msg->addr.addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
        && (msg->msg.netfn == IPMI_NETFN_APP_RESPONSE)
        && (msg->msg.cmd == IPMI_GET_CHANNEL_INFO_CMD)) {
        /* It's the one we want */
        if (msg->msg.data[0] != 0) {
            /* Got an error from the channel, just go on. */

            if (msg->msg.data[0] == IPMI_INVALID_COMMAND_ERR) {
                /*
                 * If the MC does not support this
                 * command, that is legal.  We just
                 * assume it has one IPMB at channel
                 * zero.
                 */
                intf->channels[0].medium
                    = IPMI_CHANNEL_MEDIUM_IPMB;
                intf->channels[0].protocol
                    = IPMI_CHANNEL_PROTOCOL_IPMB;
                rv = -ENOSYS;

                intf->curr_channel = IPMI_MAX_CHANNELS;
                wake_up(&intf->waitq);
                goto out;
            }
            goto next_channel;
        }
        if (msg->msg.data_len < 4) {
            /* Message not big enough, just go on. */
            goto next_channel;
        }
        chan = intf->curr_channel;
        intf->channels[chan].medium = msg->msg.data[2] & 0x7f;
        intf->channels[chan].protocol = msg->msg.data[3] & 0x1f;

 next_channel:
        intf->curr_channel++;
        if (intf->curr_channel >= IPMI_MAX_CHANNELS)
            wake_up(&intf->waitq);
        else
            rv = send_channel_info_cmd(intf, intf->curr_channel);

        if (rv) {
            /* Got an error somehow, just give up. */
            intf->curr_channel = IPMI_MAX_CHANNELS;
            wake_up(&intf->waitq);

            printk(KERN_WARNING PFX
                   "Error sending channel information: %d\n",
                   rv);
        }
    }
 out:
    return;
}

static void ipmi_poll(ipmi_smi_t intf)
{
    if (intf->handlers->poll)
        intf->handlers->poll(intf->send_info);
    /* In case something came in */
    handle_new_recv_msgs(intf);
}

void ipmi_poll_interface(ipmi_user_t user)
{
    ipmi_poll(user->intf);
}
EXPORT_SYMBOL(ipmi_poll_interface);

int ipmi_register_smi(struct ipmi_smi_handlers *handlers,
              void             *send_info,
              struct ipmi_device_id    *device_id,
              struct device            *si_dev,
              const char               *sysfs_name,
              unsigned char            slave_addr)
{
    int              i, j;
    int              rv;
    ipmi_smi_t       intf;
    ipmi_smi_t       tintf;
    struct list_head *link;

    /*
     * Make sure the driver is actually initialized, this handles
     * problems with initialization order.
     */
    if (!initialized) {
        rv = ipmi_init_msghandler();
        if (rv)
            return rv;
        /*
         * The init code doesn't return an error if it was turned
         * off, but it won't initialize.  Check that.
         */
        if (!initialized)
            return -ENODEV;
    }

    intf = kzalloc(sizeof(*intf), GFP_KERNEL);
    if (!intf)
        return -ENOMEM;

    intf->ipmi_version_major = ipmi_version_major(device_id);
    intf->ipmi_version_minor = ipmi_version_minor(device_id);

    intf->bmc = kzalloc(sizeof(*intf->bmc), GFP_KERNEL);
    if (!intf->bmc) {
        kfree(intf);
        return -ENOMEM;
    }
    intf->intf_num = -1; /* Mark it invalid for now. */
    kref_init(&intf->refcount);
    intf->bmc->id = *device_id;
    intf->si_dev = si_dev;
    for (j = 0; j < IPMI_MAX_CHANNELS; j++) {
        intf->channels[j].address = IPMI_BMC_SLAVE_ADDR;
        intf->channels[j].lun = 2;
    }
    if (slave_addr != 0)
        intf->channels[0].address = slave_addr;
    INIT_LIST_HEAD(&intf->users);
    intf->handlers = handlers;
    intf->send_info = send_info;
    spin_lock_init(&intf->seq_lock);
    for (j = 0; j < IPMI_IPMB_NUM_SEQ; j++) {
        intf->seq_table[j].inuse = 0;
        intf->seq_table[j].seqid = 0;
    }
    intf->curr_seq = 0;
#ifdef CONFIG_PROC_FS
    mutex_init(&intf->proc_entry_lock);
#endif
    spin_lock_init(&intf->waiting_msgs_lock);
    INIT_LIST_HEAD(&intf->waiting_msgs);
    tasklet_init(&intf->recv_tasklet,
             smi_recv_tasklet,
             (unsigned long) intf);
    atomic_set(&intf->watchdog_pretimeouts_to_deliver, 0);
    spin_lock_init(&intf->events_lock);
    INIT_LIST_HEAD(&intf->waiting_events);
    intf->waiting_events_count = 0;
    mutex_init(&intf->cmd_rcvrs_mutex);
    spin_lock_init(&intf->maintenance_mode_lock);
    INIT_LIST_HEAD(&intf->cmd_rcvrs);
    init_waitqueue_head(&intf->waitq);
    for (i = 0; i < IPMI_NUM_STATS; i++)
        atomic_set(&intf->stats[i], 0);

    intf->proc_dir = NULL;

    mutex_lock(&smi_watchers_mutex);
    mutex_lock(&ipmi_interfaces_mutex);
    /* Look for a hole in the numbers. */
    i = 0;
    link = &ipmi_interfaces;
    list_for_each_entry_rcu(tintf, &ipmi_interfaces, link) {
        if (tintf->intf_num != i) {
            link = &tintf->link;
            break;
        }
        i++;
    }
    /* Add the new interface in numeric order. */
    if (i == 0)
        list_add_rcu(&intf->link, &ipmi_interfaces);
    else
        list_add_tail_rcu(&intf->link, link);

    rv = handlers->start_processing(send_info, intf);
    if (rv)
        goto out;

    get_guid(intf);

    if ((intf->ipmi_version_major > 1)
            || ((intf->ipmi_version_major == 1)
                && (intf->ipmi_version_minor >= 5))) {
        /*
         * Start scanning the channels to see what is
         * available.
         */
        intf->null_user_handler = channel_handler;
        intf->curr_channel = 0;
        rv = send_channel_info_cmd(intf, 0);
        if (rv)
            goto out;

        /* Wait for the channel info to be read. */
        wait_event(intf->waitq,
               intf->curr_channel >= IPMI_MAX_CHANNELS);
        intf->null_user_handler = NULL;
    } else {
        /* Assume a single IPMB channel at zero. */
        intf->channels[0].medium = IPMI_CHANNEL_MEDIUM_IPMB;
        intf->channels[0].protocol = IPMI_CHANNEL_PROTOCOL_IPMB;
        intf->curr_channel = IPMI_MAX_CHANNELS;
    }

    if (rv == 0)
        rv = add_proc_entries(intf, i);

    rv = ipmi_bmc_register(intf, i, sysfs_name);

 out:
    if (rv) {
        if (intf->proc_dir)
            remove_proc_entries(intf);
        intf->handlers = NULL;
        list_del_rcu(&intf->link);
        mutex_unlock(&ipmi_interfaces_mutex);
        mutex_unlock(&smi_watchers_mutex);
        synchronize_rcu();
        kref_put(&intf->refcount, intf_free);
    } else {
        /*
         * Keep memory order straight for RCU readers.  Make
         * sure everything else is committed to memory before
         * setting intf_num to mark the interface valid.
         */
        smp_wmb();
        intf->intf_num = i;
        mutex_unlock(&ipmi_interfaces_mutex);
        /* After this point the interface is legal to use. */
        call_smi_watchers(i, intf->si_dev);
        mutex_unlock(&smi_watchers_mutex);
    }

    return rv;
}
EXPORT_SYMBOL(ipmi_register_smi);

static void cleanup_smi_msgs(ipmi_smi_t intf)
{
    int              i;
    struct seq_table *ent;

    /* No need for locks, the interface is down. */
    for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++) {
        ent = &(intf->seq_table[i]);
        if (!ent->inuse)
            continue;
        deliver_err_response(ent->recv_msg, IPMI_ERR_UNSPECIFIED);
    }
}

int ipmi_unregister_smi(ipmi_smi_t intf)
{
    struct ipmi_smi_watcher *w;
    int    intf_num = intf->intf_num;

    ipmi_bmc_unregister(intf);

    mutex_lock(&smi_watchers_mutex);
    mutex_lock(&ipmi_interfaces_mutex);
    intf->intf_num = -1;
    intf->handlers = NULL;
    list_del_rcu(&intf->link);
    mutex_unlock(&ipmi_interfaces_mutex);
    synchronize_rcu();

    cleanup_smi_msgs(intf);

    remove_proc_entries(intf);

    /*
     * Call all the watcher interfaces to tell them that
     * an interface is gone.
     */
    list_for_each_entry(w, &smi_watchers, link)
        w->smi_gone(intf_num);
    mutex_unlock(&smi_watchers_mutex);

    kref_put(&intf->refcount, intf_free);
    return 0;
}
EXPORT_SYMBOL(ipmi_unregister_smi);

static int handle_ipmb_get_msg_rsp(ipmi_smi_t          intf,
                   struct ipmi_smi_msg *msg)
{
    struct ipmi_ipmb_addr ipmb_addr;
    struct ipmi_recv_msg  *recv_msg;

    /*
     * This is 11, not 10, because the response must contain a
     * completion code.
     */
    if (msg->rsp_size < 11) {
        /* Message not big enough, just ignore it. */
        ipmi_inc_stat(intf, invalid_ipmb_responses);
        return 0;
    }

    if (msg->rsp[2] != 0) {
        /* An error getting the response, just ignore it. */
        return 0;
    }

    ipmb_addr.addr_type = IPMI_IPMB_ADDR_TYPE;
    ipmb_addr.slave_addr = msg->rsp[6];
    ipmb_addr.channel = msg->rsp[3] & 0x0f;
    ipmb_addr.lun = msg->rsp[7] & 3;

    /*
     * It's a response from a remote entity.  Look up the sequence
     * number and handle the response.
     */
    if (intf_find_seq(intf,
              msg->rsp[7] >> 2,
              msg->rsp[3] & 0x0f,
              msg->rsp[8],
              (msg->rsp[4] >> 2) & (~1),
              (struct ipmi_addr *) &(ipmb_addr),
              &recv_msg)) {
        /*
         * We were unable to find the sequence number,
         * so just nuke the message.
         */
        ipmi_inc_stat(intf, unhandled_ipmb_responses);
        return 0;
    }

    memcpy(recv_msg->msg_data,
           &(msg->rsp[9]),
           msg->rsp_size - 9);
    /*
     * The other fields matched, so no need to set them, except
     * for netfn, which needs to be the response that was
     * returned, not the request value.
     */
    recv_msg->msg.netfn = msg->rsp[4] >> 2;
    recv_msg->msg.data = recv_msg->msg_data;
    recv_msg->msg.data_len = msg->rsp_size - 10;
    recv_msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
    ipmi_inc_stat(intf, handled_ipmb_responses);
    deliver_response(recv_msg);

    return 0;
}

static int handle_ipmb_get_msg_cmd(ipmi_smi_t          intf,
                   struct ipmi_smi_msg *msg)
{
    struct cmd_rcvr          *rcvr;
    int                      rv = 0;
    unsigned char            netfn;
    unsigned char            cmd;
    unsigned char            chan;
    ipmi_user_t              user = NULL;
    struct ipmi_ipmb_addr    *ipmb_addr;
    struct ipmi_recv_msg     *recv_msg;
    struct ipmi_smi_handlers *handlers;

    if (msg->rsp_size < 10) {
        /* Message not big enough, just ignore it. */
        ipmi_inc_stat(intf, invalid_commands);
        return 0;
    }

    if (msg->rsp[2] != 0) {
        /* An error getting the response, just ignore it. */
        return 0;
    }

    netfn = msg->rsp[4] >> 2;
    cmd = msg->rsp[8];
    chan = msg->rsp[3] & 0xf;

    rcu_read_lock();
    rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
    if (rcvr) {
        user = rcvr->user;
        kref_get(&user->refcount);
    } else
        user = NULL;
    rcu_read_unlock();

    if (user == NULL) {
        /* We didn't find a user, deliver an error response. */
        ipmi_inc_stat(intf, unhandled_commands);

        msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
        msg->data[1] = IPMI_SEND_MSG_CMD;
        msg->data[2] = msg->rsp[3];
        msg->data[3] = msg->rsp[6];
        msg->data[4] = ((netfn + 1) << 2) | (msg->rsp[7] & 0x3);
        msg->data[5] = ipmb_checksum(&(msg->data[3]), 2);
        msg->data[6] = intf->channels[msg->rsp[3] & 0xf].address;
        /* rqseq/lun */
        msg->data[7] = (msg->rsp[7] & 0xfc) | (msg->rsp[4] & 0x3);
        msg->data[8] = msg->rsp[8]; /* cmd */
        msg->data[9] = IPMI_INVALID_CMD_COMPLETION_CODE;
        msg->data[10] = ipmb_checksum(&(msg->data[6]), 4);
        msg->data_size = 11;

#ifdef DEBUG_MSGING
    {
        int m;
        printk("Invalid command:");
        for (m = 0; m < msg->data_size; m++)
            printk(" %2.2x", msg->data[m]);
        printk("\n");
    }
#endif
        rcu_read_lock();
        handlers = intf->handlers;
        if (handlers) {
            handlers->sender(intf->send_info, msg, 0);
            /*
             * We used the message, so return the value
             * that causes it to not be freed or
             * queued.
             */
            rv = -1;
        }
        rcu_read_unlock();
    } else {
        /* Deliver the message to the user. */
        ipmi_inc_stat(intf, handled_commands);

        recv_msg = ipmi_alloc_recv_msg();
        if (!recv_msg) {
            /*
             * We couldn't allocate memory for the
             * message, so requeue it for handling
             * later.
             */
            rv = 1;
            kref_put(&user->refcount, free_user);
        } else {
            /* Extract the source address from the data. */
            ipmb_addr = (struct ipmi_ipmb_addr *) &recv_msg->addr;
            ipmb_addr->addr_type = IPMI_IPMB_ADDR_TYPE;
            ipmb_addr->slave_addr = msg->rsp[6];
            ipmb_addr->lun = msg->rsp[7] & 3;
            ipmb_addr->channel = msg->rsp[3] & 0xf;

            /*
             * Extract the rest of the message information
             * from the IPMB header.
             */
            recv_msg->user = user;
            recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
            recv_msg->msgid = msg->rsp[7] >> 2;
            recv_msg->msg.netfn = msg->rsp[4] >> 2;
            recv_msg->msg.cmd = msg->rsp[8];
            recv_msg->msg.data = recv_msg->msg_data;

            /*
             * We chop off 10, not 9 bytes because the checksum
             * at the end also needs to be removed.
             */
            recv_msg->msg.data_len = msg->rsp_size - 10;
            memcpy(recv_msg->msg_data,
                   &(msg->rsp[9]),
                   msg->rsp_size - 10);
            deliver_response(recv_msg);
        }
    }

    return rv;
}

static int handle_lan_get_msg_rsp(ipmi_smi_t          intf,
                  struct ipmi_smi_msg *msg)
{
    struct ipmi_lan_addr  lan_addr;
    struct ipmi_recv_msg  *recv_msg;


    /*
     * This is 13, not 12, because the response must contain a
     * completion code.
     */
    if (msg->rsp_size < 13) {
        /* Message not big enough, just ignore it. */
        ipmi_inc_stat(intf, invalid_lan_responses);
        return 0;
    }

    if (msg->rsp[2] != 0) {
        /* An error getting the response, just ignore it. */
        return 0;
    }

    lan_addr.addr_type = IPMI_LAN_ADDR_TYPE;
    lan_addr.session_handle = msg->rsp[4];
    lan_addr.remote_SWID = msg->rsp[8];
    lan_addr.local_SWID = msg->rsp[5];
    lan_addr.channel = msg->rsp[3] & 0x0f;
    lan_addr.privilege = msg->rsp[3] >> 4;
    lan_addr.lun = msg->rsp[9] & 3;

    /*
     * It's a response from a remote entity.  Look up the sequence
     * number and handle the response.
     */
    if (intf_find_seq(intf,
              msg->rsp[9] >> 2,
              msg->rsp[3] & 0x0f,
              msg->rsp[10],
              (msg->rsp[6] >> 2) & (~1),
              (struct ipmi_addr *) &(lan_addr),
              &recv_msg)) {
        /*
         * We were unable to find the sequence number,
         * so just nuke the message.
         */
        ipmi_inc_stat(intf, unhandled_lan_responses);
        return 0;
    }

    memcpy(recv_msg->msg_data,
           &(msg->rsp[11]),
           msg->rsp_size - 11);
    /*
     * The other fields matched, so no need to set them, except
     * for netfn, which needs to be the response that was
     * returned, not the request value.
     */
    recv_msg->msg.netfn = msg->rsp[6] >> 2;
    recv_msg->msg.data = recv_msg->msg_data;
    recv_msg->msg.data_len = msg->rsp_size - 12;
    recv_msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
    ipmi_inc_stat(intf, handled_lan_responses);
    deliver_response(recv_msg);

    return 0;
}

static int handle_lan_get_msg_cmd(ipmi_smi_t          intf,
                  struct ipmi_smi_msg *msg)
{
    struct cmd_rcvr          *rcvr;
    int                      rv = 0;
    unsigned char            netfn;
    unsigned char            cmd;
    unsigned char            chan;
    ipmi_user_t              user = NULL;
    struct ipmi_lan_addr     *lan_addr;
    struct ipmi_recv_msg     *recv_msg;

    if (msg->rsp_size < 12) {
        /* Message not big enough, just ignore it. */
        ipmi_inc_stat(intf, invalid_commands);
        return 0;
    }

    if (msg->rsp[2] != 0) {
        /* An error getting the response, just ignore it. */
        return 0;
    }

    netfn = msg->rsp[6] >> 2;
    cmd = msg->rsp[10];
    chan = msg->rsp[3] & 0xf;

    rcu_read_lock();
    rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
    if (rcvr) {
        user = rcvr->user;
        kref_get(&user->refcount);
    } else
        user = NULL;
    rcu_read_unlock();

    if (user == NULL) {
        /* We didn't find a user, just give up. */
        ipmi_inc_stat(intf, unhandled_commands);

        /*
         * Don't do anything with these messages, just allow
         * them to be freed.
         */
        rv = 0;
    } else {
        /* Deliver the message to the user. */
        ipmi_inc_stat(intf, handled_commands);

        recv_msg = ipmi_alloc_recv_msg();
        if (!recv_msg) {
            /*
             * We couldn't allocate memory for the
             * message, so requeue it for handling later.
             */
            rv = 1;
            kref_put(&user->refcount, free_user);
        } else {
            /* Extract the source address from the data. */
            lan_addr = (struct ipmi_lan_addr *) &recv_msg->addr;
            lan_addr->addr_type = IPMI_LAN_ADDR_TYPE;
            lan_addr->session_handle = msg->rsp[4];
            lan_addr->remote_SWID = msg->rsp[8];
            lan_addr->local_SWID = msg->rsp[5];
            lan_addr->lun = msg->rsp[9] & 3;
            lan_addr->channel = msg->rsp[3] & 0xf;
            lan_addr->privilege = msg->rsp[3] >> 4;

            /*
             * Extract the rest of the message information
             * from the IPMB header.
             */
            recv_msg->user = user;
            recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
            recv_msg->msgid = msg->rsp[9] >> 2;
            recv_msg->msg.netfn = msg->rsp[6] >> 2;
            recv_msg->msg.cmd = msg->rsp[10];
            recv_msg->msg.data = recv_msg->msg_data;

            /*
             * We chop off 12, not 11 bytes because the checksum
             * at the end also needs to be removed.
             */
            recv_msg->msg.data_len = msg->rsp_size - 12;
            memcpy(recv_msg->msg_data,
                   &(msg->rsp[11]),
                   msg->rsp_size - 12);
            deliver_response(recv_msg);
        }
    }

    return rv;
}

/*
 * This routine will handle "Get Message" command responses with
 * channels that use an OEM Medium. The message format belongs to
 * the OEM.  See IPMI 2.0 specification, Chapter 6 and
 * Chapter 22, sections 22.6 and 22.24 for more details.
 */
static int handle_oem_get_msg_cmd(ipmi_smi_t          intf,
                  struct ipmi_smi_msg *msg)
{
    struct cmd_rcvr       *rcvr;
    int                   rv = 0;
    unsigned char         netfn;
    unsigned char         cmd;
    unsigned char         chan;
    ipmi_user_t           user = NULL;
    struct ipmi_system_interface_addr *smi_addr;
    struct ipmi_recv_msg  *recv_msg;

    /*
     * We expect the OEM SW to perform error checking
     * so we just do some basic sanity checks
     */
    if (msg->rsp_size < 4) {
        /* Message not big enough, just ignore it. */
        ipmi_inc_stat(intf, invalid_commands);
        return 0;
    }

    if (msg->rsp[2] != 0) {
        /* An error getting the response, just ignore it. */
        return 0;
    }

    /*
     * This is an OEM Message so the OEM needs to know how
     * handle the message. We do no interpretation.
     */
    netfn = msg->rsp[0] >> 2;
    cmd = msg->rsp[1];
    chan = msg->rsp[3] & 0xf;

    rcu_read_lock();
    rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
    if (rcvr) {
        user = rcvr->user;
        kref_get(&user->refcount);
    } else
        user = NULL;
    rcu_read_unlock();

    if (user == NULL) {
        /* We didn't find a user, just give up. */
        ipmi_inc_stat(intf, unhandled_commands);

        /*
         * Don't do anything with these messages, just allow
         * them to be freed.
         */

        rv = 0;
    } else {
        /* Deliver the message to the user. */
        ipmi_inc_stat(intf, handled_commands);

        recv_msg = ipmi_alloc_recv_msg();
        if (!recv_msg) {
            /*
             * We couldn't allocate memory for the
             * message, so requeue it for handling
             * later.
             */
            rv = 1;
            kref_put(&user->refcount, free_user);
        } else {
            /*
             * OEM Messages are expected to be delivered via
             * the system interface to SMS software.  We might
             * need to visit this again depending on OEM
             * requirements
             */
            smi_addr = ((struct ipmi_system_interface_addr *)
                    &(recv_msg->addr));
            smi_addr->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
            smi_addr->channel = IPMI_BMC_CHANNEL;
            smi_addr->lun = msg->rsp[0] & 3;

            recv_msg->user = user;
            recv_msg->user_msg_data = NULL;
            recv_msg->recv_type = IPMI_OEM_RECV_TYPE;
            recv_msg->msg.netfn = msg->rsp[0] >> 2;
            recv_msg->msg.cmd = msg->rsp[1];
            recv_msg->msg.data = recv_msg->msg_data;

            /*
             * The message starts at byte 4 which follows the
             * the Channel Byte in the "GET MESSAGE" command
             */
            recv_msg->msg.data_len = msg->rsp_size - 4;
            memcpy(recv_msg->msg_data,
                   &(msg->rsp[4]),
                   msg->rsp_size - 4);
            deliver_response(recv_msg);
        }
    }

    return rv;
}

static void copy_event_into_recv_msg(struct ipmi_recv_msg *recv_msg,
                     struct ipmi_smi_msg  *msg)
{
    struct ipmi_system_interface_addr *smi_addr;

    recv_msg->msgid = 0;
    smi_addr = (struct ipmi_system_interface_addr *) &(recv_msg->addr);
    smi_addr->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
    smi_addr->channel = IPMI_BMC_CHANNEL;
    smi_addr->lun = msg->rsp[0] & 3;
    recv_msg->recv_type = IPMI_ASYNC_EVENT_RECV_TYPE;
    recv_msg->msg.netfn = msg->rsp[0] >> 2;
    recv_msg->msg.cmd = msg->rsp[1];
    memcpy(recv_msg->msg_data, &(msg->rsp[3]), msg->rsp_size - 3);
    recv_msg->msg.data = recv_msg->msg_data;
    recv_msg->msg.data_len = msg->rsp_size - 3;
}

static int handle_read_event_rsp(ipmi_smi_t          intf,
                 struct ipmi_smi_msg *msg)
{
    struct ipmi_recv_msg *recv_msg, *recv_msg2;
    struct list_head     msgs;
    ipmi_user_t          user;
    int                  rv = 0;
    int                  deliver_count = 0;
    unsigned long        flags;

    if (msg->rsp_size < 19) {
        /* Message is too small to be an IPMB event. */
        ipmi_inc_stat(intf, invalid_events);
        return 0;
    }

    if (msg->rsp[2] != 0) {
        /* An error getting the event, just ignore it. */
        return 0;
    }

    INIT_LIST_HEAD(&msgs);

    spin_lock_irqsave(&intf->events_lock, flags);

    ipmi_inc_stat(intf, events);

    /*
     * Allocate and fill in one message for every user that is
     * getting events.
     */
    rcu_read_lock();
    list_for_each_entry_rcu(user, &intf->users, link) {
        if (!user->gets_events)
            continue;

        recv_msg = ipmi_alloc_recv_msg();
        if (!recv_msg) {
            rcu_read_unlock();
            list_for_each_entry_safe(recv_msg, recv_msg2, &msgs,
                         link) {
                list_del(&recv_msg->link);
                ipmi_free_recv_msg(recv_msg);
            }
            /*
             * We couldn't allocate memory for the
             * message, so requeue it for handling
             * later.
             */
            rv = 1;
            goto out;
        }

        deliver_count++;

        copy_event_into_recv_msg(recv_msg, msg);
        recv_msg->user = user;
        kref_get(&user->refcount);
        list_add_tail(&(recv_msg->link), &msgs);
    }
    rcu_read_unlock();

    if (deliver_count) {
        /* Now deliver all the messages. */
        list_for_each_entry_safe(recv_msg, recv_msg2, &msgs, link) {
            list_del(&recv_msg->link);
            deliver_response(recv_msg);
        }
    } else if (intf->waiting_events_count < MAX_EVENTS_IN_QUEUE) {
        /*
         * No one to receive the message, put it in queue if there's
         * not already too many things in the queue.
         */
        recv_msg = ipmi_alloc_recv_msg();
        if (!recv_msg) {
            /*
             * We couldn't allocate memory for the
             * message, so requeue it for handling
             * later.
             */
            rv = 1;
            goto out;
        }

        copy_event_into_recv_msg(recv_msg, msg);
        list_add_tail(&(recv_msg->link), &(intf->waiting_events));
        intf->waiting_events_count++;
    } else if (!intf->event_msg_printed) {
        /*
         * There's too many things in the queue, discard this
         * message.
         */
        printk(KERN_WARNING PFX "Event queue full, discarding"
               " incoming events\n");
        intf->event_msg_printed = 1;
    }

 out:
    spin_unlock_irqrestore(&(intf->events_lock), flags);

    return rv;
}

static int handle_bmc_rsp(ipmi_smi_t          intf,
              struct ipmi_smi_msg *msg)
{
    struct ipmi_recv_msg *recv_msg;
    struct ipmi_user     *user;

    recv_msg = (struct ipmi_recv_msg *) msg->user_data;
    if (recv_msg == NULL) {
        printk(KERN_WARNING
               "IPMI message received with no owner. This\n"
               "could be because of a malformed message, or\n"
               "because of a hardware error.  Contact your\n"
               "hardware vender for assistance\n");
        return 0;
    }

    user = recv_msg->user;
    /* Make sure the user still exists. */
    if (user && !user->valid) {
        /* The user for the message went away, so give up. */
        ipmi_inc_stat(intf, unhandled_local_responses);
        ipmi_free_recv_msg(recv_msg);
    } else {
        struct ipmi_system_interface_addr *smi_addr;

        ipmi_inc_stat(intf, handled_local_responses);
        recv_msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
        recv_msg->msgid = msg->msgid;
        smi_addr = ((struct ipmi_system_interface_addr *)
                &(recv_msg->addr));
        smi_addr->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
        smi_addr->channel = IPMI_BMC_CHANNEL;
        smi_addr->lun = msg->rsp[0] & 3;
        recv_msg->msg.netfn = msg->rsp[0] >> 2;
        recv_msg->msg.cmd = msg->rsp[1];
        memcpy(recv_msg->msg_data,
               &(msg->rsp[2]),
               msg->rsp_size - 2);
        recv_msg->msg.data = recv_msg->msg_data;
        recv_msg->msg.data_len = msg->rsp_size - 2;
        deliver_response(recv_msg);
    }

    return 0;
}

/*
 * Handle a received message.  Return 1 if the message should be requeued,
 * 0 if the message should be freed, or -1 if the message should not
 * be freed or requeued.
 */
static int handle_one_recv_msg(ipmi_smi_t          intf,
                   struct ipmi_smi_msg *msg)
{
    int requeue;
    int chan;

#ifdef DEBUG_MSGING
    int m;
    printk("Recv:");
    for (m = 0; m < msg->rsp_size; m++)
        printk(" %2.2x", msg->rsp[m]);
    printk("\n");
#endif
    if (msg->rsp_size < 2) {
        /* Message is too small to be correct. */
        printk(KERN_WARNING PFX "BMC returned to small a message"
               " for netfn %x cmd %x, got %d bytes\n",
               (msg->data[0] >> 2) | 1, msg->data[1], msg->rsp_size);

        /* Generate an error response for the message. */
        msg->rsp[0] = msg->data[0] | (1 << 2);
        msg->rsp[1] = msg->data[1];
        msg->rsp[2] = IPMI_ERR_UNSPECIFIED;
        msg->rsp_size = 3;
    } else if (((msg->rsp[0] >> 2) != ((msg->data[0] >> 2) | 1))
           || (msg->rsp[1] != msg->data[1])) {
        /*
         * The NetFN and Command in the response is not even
         * marginally correct.
         */
        printk(KERN_WARNING PFX "BMC returned incorrect response,"
               " expected netfn %x cmd %x, got netfn %x cmd %x\n",
               (msg->data[0] >> 2) | 1, msg->data[1],
               msg->rsp[0] >> 2, msg->rsp[1]);

        /* Generate an error response for the message. */
        msg->rsp[0] = msg->data[0] | (1 << 2);
        msg->rsp[1] = msg->data[1];
        msg->rsp[2] = IPMI_ERR_UNSPECIFIED;
        msg->rsp_size = 3;
    }

    if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
        && (msg->rsp[1] == IPMI_SEND_MSG_CMD)
        && (msg->user_data != NULL)) {
        /*
         * It's a response to a response we sent.  For this we
         * deliver a send message response to the user.
         */
        struct ipmi_recv_msg     *recv_msg = msg->user_data;

        requeue = 0;
        if (msg->rsp_size < 2)
            /* Message is too small to be correct. */
            goto out;

        chan = msg->data[2] & 0x0f;
        if (chan >= IPMI_MAX_CHANNELS)
            /* Invalid channel number */
            goto out;

        if (!recv_msg)
            goto out;

        /* Make sure the user still exists. */
        if (!recv_msg->user || !recv_msg->user->valid)
            goto out;

        recv_msg->recv_type = IPMI_RESPONSE_RESPONSE_TYPE;
        recv_msg->msg.data = recv_msg->msg_data;
        recv_msg->msg.data_len = 1;
        recv_msg->msg_data[0] = msg->rsp[2];
        deliver_response(recv_msg);
    } else if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
           && (msg->rsp[1] == IPMI_GET_MSG_CMD)) {
        /* It's from the receive queue. */
        chan = msg->rsp[3] & 0xf;
        if (chan >= IPMI_MAX_CHANNELS) {
            /* Invalid channel number */
            requeue = 0;
            goto out;
        }

        /*
         * We need to make sure the channels have been initialized.
         * The channel_handler routine will set the "curr_channel"
         * equal to or greater than IPMI_MAX_CHANNELS when all the
         * channels for this interface have been initialized.
         */
        if (intf->curr_channel < IPMI_MAX_CHANNELS) {
            requeue = 0; /* Throw the message away */
            goto out;
        }

        switch (intf->channels[chan].medium) {
        case IPMI_CHANNEL_MEDIUM_IPMB:
            if (msg->rsp[4] & 0x04) {
                /*
                 * It's a response, so find the
                 * requesting message and send it up.
                 */
                requeue = handle_ipmb_get_msg_rsp(intf, msg);
            } else {
                /*
                 * It's a command to the SMS from some other
                 * entity.  Handle that.
                 */
                requeue = handle_ipmb_get_msg_cmd(intf, msg);
            }
            break;

        case IPMI_CHANNEL_MEDIUM_8023LAN:
        case IPMI_CHANNEL_MEDIUM_ASYNC:
            if (msg->rsp[6] & 0x04) {
                /*
                 * It's a response, so find the
                 * requesting message and send it up.
                 */
                requeue = handle_lan_get_msg_rsp(intf, msg);
            } else {
                /*
                 * It's a command to the SMS from some other
                 * entity.  Handle that.
                 */
                requeue = handle_lan_get_msg_cmd(intf, msg);
            }
            break;

        default:
            /* Check for OEM Channels.  Clients had better
               register for these commands. */
            if ((intf->channels[chan].medium
                 >= IPMI_CHANNEL_MEDIUM_OEM_MIN)
                && (intf->channels[chan].medium
                <= IPMI_CHANNEL_MEDIUM_OEM_MAX)) {
                requeue = handle_oem_get_msg_cmd(intf, msg);
            } else {
                /*
                 * We don't handle the channel type, so just
                 * free the message.
                 */
                requeue = 0;
            }
        }

    } else if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
           && (msg->rsp[1] == IPMI_READ_EVENT_MSG_BUFFER_CMD)) {
        /* It's an asyncronous event. */
        requeue = handle_read_event_rsp(intf, msg);
    } else {
        /* It's a response from the local BMC. */
        requeue = handle_bmc_rsp(intf, msg);
    }

 out:
    return requeue;
}

/*
 * If there are messages in the queue or pretimeouts, handle them.
 */
static void handle_new_recv_msgs(ipmi_smi_t intf)
{
    struct ipmi_smi_msg  *smi_msg;
    unsigned long        flags = 0;
    int                  rv;
    int                  run_to_completion = intf->run_to_completion;

    /* See if any waiting messages need to be processed. */
    if (!run_to_completion)
        spin_lock_irqsave(&intf->waiting_msgs_lock, flags);
    while (!list_empty(&intf->waiting_msgs)) {
        smi_msg = list_entry(intf->waiting_msgs.next,
                     struct ipmi_smi_msg, link);
        list_del(&smi_msg->link);
        if (!run_to_completion)
            spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags);
        rv = handle_one_recv_msg(intf, smi_msg);
        if (!run_to_completion)
            spin_lock_irqsave(&intf->waiting_msgs_lock, flags);
        if (rv == 0) {
            /* Message handled */
            ipmi_free_smi_msg(smi_msg);
        } else if (rv < 0) {
            /* Fatal error on the message, del but don't free. */
        } else {
            /*
             * To preserve message order, quit if we
             * can't handle a message.
             */
            list_add(&smi_msg->link, &intf->waiting_msgs);
            break;
        }
    }
    if (!run_to_completion)
        spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags);

    /*
     * If the pretimout count is non-zero, decrement one from it and
     * deliver pretimeouts to all the users.
     */
    if (atomic_add_unless(&intf->watchdog_pretimeouts_to_deliver, -1, 0)) {
        ipmi_user_t user;

        rcu_read_lock();
        list_for_each_entry_rcu(user, &intf->users, link) {
            if (user->handler->ipmi_watchdog_pretimeout)
                user->handler->ipmi_watchdog_pretimeout(
                    user->handler_data);
        }
        rcu_read_unlock();
    }
}

static void smi_recv_tasklet(unsigned long val)
{
    handle_new_recv_msgs((ipmi_smi_t) val);
}

/* Handle a new message from the lower layer. */
void ipmi_smi_msg_received(ipmi_smi_t          intf,
               struct ipmi_smi_msg *msg)
{
    unsigned long flags = 0; /* keep us warning-free. */
    int           run_to_completion;


    if ((msg->data_size >= 2)
        && (msg->data[0] == (IPMI_NETFN_APP_REQUEST << 2))
        && (msg->data[1] == IPMI_SEND_MSG_CMD)
        && (msg->user_data == NULL)) {
        /*
         * This is the local response to a command send, start
         * the timer for these.  The user_data will not be
         * NULL if this is a response send, and we will let
         * response sends just go through.
         */

        /*
         * Check for errors, if we get certain errors (ones
         * that mean basically we can try again later), we
         * ignore them and start the timer.  Otherwise we
         * report the error immediately.
         */
        if ((msg->rsp_size >= 3) && (msg->rsp[2] != 0)
            && (msg->rsp[2] != IPMI_NODE_BUSY_ERR)
            && (msg->rsp[2] != IPMI_LOST_ARBITRATION_ERR)
            && (msg->rsp[2] != IPMI_BUS_ERR)
            && (msg->rsp[2] != IPMI_NAK_ON_WRITE_ERR)) {
            int chan = msg->rsp[3] & 0xf;

            /* Got an error sending the message, handle it. */
            if (chan >= IPMI_MAX_CHANNELS)
                ; /* This shouldn't happen */
            else if ((intf->channels[chan].medium
                  == IPMI_CHANNEL_MEDIUM_8023LAN)
                 || (intf->channels[chan].medium
                     == IPMI_CHANNEL_MEDIUM_ASYNC))
                ipmi_inc_stat(intf, sent_lan_command_errs);
            else
                ipmi_inc_stat(intf, sent_ipmb_command_errs);
            intf_err_seq(intf, msg->msgid, msg->rsp[2]);
        } else
            /* The message was sent, start the timer. */
            intf_start_seq_timer(intf, msg->msgid);

        ipmi_free_smi_msg(msg);
        goto out;
    }

    /*
     * To preserve message order, if the list is not empty, we
     * tack this message onto the end of the list.
     */
    run_to_completion = intf->run_to_completion;
    if (!run_to_completion)
        spin_lock_irqsave(&intf->waiting_msgs_lock, flags);
    list_add_tail(&msg->link, &intf->waiting_msgs);
    if (!run_to_completion)
        spin_unlock_irqrestore(&intf->waiting_msgs_lock, flags);

    tasklet_schedule(&intf->recv_tasklet);
 out:
    return;
}
EXPORT_SYMBOL(ipmi_smi_msg_received);

void ipmi_smi_watchdog_pretimeout(ipmi_smi_t intf)
{
    atomic_set(&intf->watchdog_pretimeouts_to_deliver, 1);
    tasklet_schedule(&intf->recv_tasklet);
}
EXPORT_SYMBOL(ipmi_smi_watchdog_pretimeout);

static struct ipmi_smi_msg *
smi_from_recv_msg(ipmi_smi_t intf, struct ipmi_recv_msg *recv_msg,
          unsigned char seq, long seqid)
{
    struct ipmi_smi_msg *smi_msg = ipmi_alloc_smi_msg();
    if (!smi_msg)
        /*
         * If we can't allocate the message, then just return, we
         * get 4 retries, so this should be ok.
         */
        return NULL;

    memcpy(smi_msg->data, recv_msg->msg.data, recv_msg->msg.data_len);
    smi_msg->data_size = recv_msg->msg.data_len;
    smi_msg->msgid = STORE_SEQ_IN_MSGID(seq, seqid);

#ifdef DEBUG_MSGING
    {
        int m;
        printk("Resend: ");
        for (m = 0; m < smi_msg->data_size; m++)
            printk(" %2.2x", smi_msg->data[m]);
        printk("\n");
    }
#endif
    return smi_msg;
}

static void check_msg_timeout(ipmi_smi_t intf, struct seq_table *ent,
                  struct list_head *timeouts, long timeout_period,
                  int slot, unsigned long *flags)
{
    struct ipmi_recv_msg     *msg;
    struct ipmi_smi_handlers *handlers;

    if (intf->intf_num == -1)
        return;

    if (!ent->inuse)
        return;

    ent->timeout -= timeout_period;
    if (ent->timeout > 0)
        return;

    if (ent->retries_left == 0) {
        /* The message has used all its retries. */
        ent->inuse = 0;
        msg = ent->recv_msg;
        list_add_tail(&msg->link, timeouts);
        if (ent->broadcast)
            ipmi_inc_stat(intf, timed_out_ipmb_broadcasts);
        else if (is_lan_addr(&ent->recv_msg->addr))
            ipmi_inc_stat(intf, timed_out_lan_commands);
        else
            ipmi_inc_stat(intf, timed_out_ipmb_commands);
    } else {
        struct ipmi_smi_msg *smi_msg;
        /* More retries, send again. */

        /*
         * Start with the max timer, set to normal timer after
         * the message is sent.
         */
        ent->timeout = MAX_MSG_TIMEOUT;
        ent->retries_left--;
        smi_msg = smi_from_recv_msg(intf, ent->recv_msg, slot,
                        ent->seqid);
        if (!smi_msg) {
            if (is_lan_addr(&ent->recv_msg->addr))
                ipmi_inc_stat(intf,
                          dropped_rexmit_lan_commands);
            else
                ipmi_inc_stat(intf,
                          dropped_rexmit_ipmb_commands);
            return;
        }

        spin_unlock_irqrestore(&intf->seq_lock, *flags);

        /*
         * Send the new message.  We send with a zero
         * priority.  It timed out, I doubt time is that
         * critical now, and high priority messages are really
         * only for messages to the local MC, which don't get
         * resent.
         */
        handlers = intf->handlers;
        if (handlers) {
            if (is_lan_addr(&ent->recv_msg->addr))
                ipmi_inc_stat(intf,
                          retransmitted_lan_commands);
            else
                ipmi_inc_stat(intf,
                          retransmitted_ipmb_commands);

            intf->handlers->sender(intf->send_info,
                           smi_msg, 0);
        } else
            ipmi_free_smi_msg(smi_msg);

        spin_lock_irqsave(&intf->seq_lock, *flags);
    }
}

static void ipmi_timeout_handler(long timeout_period)
{
    ipmi_smi_t           intf;
    struct list_head     timeouts;
    struct ipmi_recv_msg *msg, *msg2;
    unsigned long        flags;
    int                  i;

    rcu_read_lock();
    list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
        tasklet_schedule(&intf->recv_tasklet);

        /*
         * Go through the seq table and find any messages that
         * have timed out, putting them in the timeouts
         * list.
         */
        INIT_LIST_HEAD(&timeouts);
        spin_lock_irqsave(&intf->seq_lock, flags);
        for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++)
            check_msg_timeout(intf, &(intf->seq_table[i]),
                      &timeouts, timeout_period, i,
                      &flags);
        spin_unlock_irqrestore(&intf->seq_lock, flags);

        list_for_each_entry_safe(msg, msg2, &timeouts, link)
            deliver_err_response(msg, IPMI_TIMEOUT_COMPLETION_CODE);

        /*
         * Maintenance mode handling.  Check the timeout
         * optimistically before we claim the lock.  It may
         * mean a timeout gets missed occasionally, but that
         * only means the timeout gets extended by one period
         * in that case.  No big deal, and it avoids the lock
         * most of the time.
         */
        if (intf->auto_maintenance_timeout > 0) {
            spin_lock_irqsave(&intf->maintenance_mode_lock, flags);
            if (intf->auto_maintenance_timeout > 0) {
                intf->auto_maintenance_timeout
                    -= timeout_period;
                if (!intf->maintenance_mode
                    && (intf->auto_maintenance_timeout <= 0)) {
                    intf->maintenance_mode_enable = 0;
                    maintenance_mode_update(intf);
                }
            }
            spin_unlock_irqrestore(&intf->maintenance_mode_lock,
                           flags);
        }
    }
    rcu_read_unlock();
}

static void ipmi_request_event(void)
{
    ipmi_smi_t               intf;
    struct ipmi_smi_handlers *handlers;

    rcu_read_lock();
    /*
     * Called from the timer, no need to check if handlers is
     * valid.
     */
    list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
        /* No event requests when in maintenance mode. */
        if (intf->maintenance_mode_enable)
            continue;

        handlers = intf->handlers;
        if (handlers)
            handlers->request_events(intf->send_info);
    }
    rcu_read_unlock();
}

static struct timer_list ipmi_timer;

/* Call every ~1000 ms. */
#define IPMI_TIMEOUT_TIME   1000

/* How many jiffies does it take to get to the timeout time. */
#define IPMI_TIMEOUT_JIFFIES    ((IPMI_TIMEOUT_TIME * HZ) / 1000)

/*
 * Request events from the queue every second (this is the number of
 * IPMI_TIMEOUT_TIMES between event requests).  Hopefully, in the
 * future, IPMI will add a way to know immediately if an event is in
 * the queue and this silliness can go away.
 */
#define IPMI_REQUEST_EV_TIME    (1000 / (IPMI_TIMEOUT_TIME))

static atomic_t stop_operation;
static unsigned int ticks_to_req_ev = IPMI_REQUEST_EV_TIME;

static void ipmi_timeout(unsigned long data)
{
    if (atomic_read(&stop_operation))
        return;

    ticks_to_req_ev--;
    if (ticks_to_req_ev == 0) {
        ipmi_request_event();
        ticks_to_req_ev = IPMI_REQUEST_EV_TIME;
    }

    ipmi_timeout_handler(IPMI_TIMEOUT_TIME);

    mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);
}


static atomic_t smi_msg_inuse_count = ATOMIC_INIT(0);
static atomic_t recv_msg_inuse_count = ATOMIC_INIT(0);

/* FIXME - convert these to slabs. */
static void free_smi_msg(struct ipmi_smi_msg *msg)
{
    atomic_dec(&smi_msg_inuse_count);
    kfree(msg);
}

struct ipmi_smi_msg *ipmi_alloc_smi_msg(void)
{
    struct ipmi_smi_msg *rv;
    rv = kmalloc(sizeof(struct ipmi_smi_msg), GFP_ATOMIC);
    if (rv) {
        rv->done = free_smi_msg;
        rv->user_data = NULL;
        atomic_inc(&smi_msg_inuse_count);
    }
    return rv;
}
EXPORT_SYMBOL(ipmi_alloc_smi_msg);

static void free_recv_msg(struct ipmi_recv_msg *msg)
{
    atomic_dec(&recv_msg_inuse_count);
    kfree(msg);
}

static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void)
{
    struct ipmi_recv_msg *rv;

    rv = kmalloc(sizeof(struct ipmi_recv_msg), GFP_ATOMIC);
    if (rv) {
        rv->user = NULL;
        rv->done = free_recv_msg;
        atomic_inc(&recv_msg_inuse_count);
    }
    return rv;
}

void ipmi_free_recv_msg(struct ipmi_recv_msg *msg)
{
    if (msg->user)
        kref_put(&msg->user->refcount, free_user);
    msg->done(msg);
}
EXPORT_SYMBOL(ipmi_free_recv_msg);

#ifdef CONFIG_IPMI_PANIC_EVENT

static atomic_t panic_done_count = ATOMIC_INIT(0);

static void dummy_smi_done_handler(struct ipmi_smi_msg *msg)
{
    atomic_dec(&panic_done_count);
}

static void dummy_recv_done_handler(struct ipmi_recv_msg *msg)
{
    atomic_dec(&panic_done_count);
}

/*
 * Inside a panic, send a message and wait for a response.
 */
static void ipmi_panic_request_and_wait(ipmi_smi_t           intf,
                    struct ipmi_addr     *addr,
                    struct kernel_ipmi_msg *msg)
{
    struct ipmi_smi_msg  smi_msg;
    struct ipmi_recv_msg recv_msg;
    int rv;

    smi_msg.done = dummy_smi_done_handler;
    recv_msg.done = dummy_recv_done_handler;
    atomic_add(2, &panic_done_count);
    rv = i_ipmi_request(NULL,
                intf,
                addr,
                0,
                msg,
                intf,
                &smi_msg,
                &recv_msg,
                0,
                intf->channels[0].address,
                intf->channels[0].lun,
                0, 1); /* Don't retry, and don't wait. */
    if (rv)
        atomic_sub(2, &panic_done_count);
    while (atomic_read(&panic_done_count) != 0)
        ipmi_poll(intf);
}

#ifdef CONFIG_IPMI_PANIC_STRING
static void event_receiver_fetcher(ipmi_smi_t intf, struct ipmi_recv_msg *msg)
{
    if ((msg->addr.addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
        && (msg->msg.netfn == IPMI_NETFN_SENSOR_EVENT_RESPONSE)
        && (msg->msg.cmd == IPMI_GET_EVENT_RECEIVER_CMD)
        && (msg->msg.data[0] == IPMI_CC_NO_ERROR)) {
        /* A get event receiver command, save it. */
        intf->event_receiver = msg->msg.data[1];
        intf->event_receiver_lun = msg->msg.data[2] & 0x3;
    }
}

static void device_id_fetcher(ipmi_smi_t intf, struct ipmi_recv_msg *msg)
{
    if ((msg->addr.addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
        && (msg->msg.netfn == IPMI_NETFN_APP_RESPONSE)
        && (msg->msg.cmd == IPMI_GET_DEVICE_ID_CMD)
        && (msg->msg.data[0] == IPMI_CC_NO_ERROR)) {
        /*
         * A get device id command, save if we are an event
         * receiver or generator.
         */
        intf->local_sel_device = (msg->msg.data[6] >> 2) & 1;
        intf->local_event_generator = (msg->msg.data[6] >> 5) & 1;
    }
}
#endif

static void send_panic_events(char *str)
{
    struct kernel_ipmi_msg            msg;
    ipmi_smi_t                        intf;
    unsigned char                     data[16];
    struct ipmi_system_interface_addr *si;
    struct ipmi_addr                  addr;

    si = (struct ipmi_system_interface_addr *) &addr;
    si->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
    si->channel = IPMI_BMC_CHANNEL;
    si->lun = 0;

    /* Fill in an event telling that we have failed. */
    msg.netfn = 0x04; /* Sensor or Event. */
    msg.cmd = 2; /* Platform event command. */
    msg.data = data;
    msg.data_len = 8;
    data[0] = 0x41; /* Kernel generator ID, IPMI table 5-4 */
    data[1] = 0x03; /* This is for IPMI 1.0. */
    data[2] = 0x20; /* OS Critical Stop, IPMI table 36-3 */
    data[4] = 0x6f; /* Sensor specific, IPMI table 36-1 */
    data[5] = 0xa1; /* Runtime stop OEM bytes 2 & 3. */

    /*
     * Put a few breadcrumbs in.  Hopefully later we can add more things
     * to make the panic events more useful.
     */
    if (str) {
        data[3] = str[0];
        data[6] = str[1];
        data[7] = str[2];
    }

    /* For every registered interface, send the event. */
    list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
        if (!intf->handlers)
            /* Interface is not ready. */
            continue;

        intf->run_to_completion = 1;
        /* Send the event announcing the panic. */
        intf->handlers->set_run_to_completion(intf->send_info, 1);
        ipmi_panic_request_and_wait(intf, &addr, &msg);
    }

#ifdef CONFIG_IPMI_PANIC_STRING
    /*
     * On every interface, dump a bunch of OEM event holding the
     * string.
     */
    if (!str)
        return;

    /* For every registered interface, send the event. */
    list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
        char                  *p = str;
        struct ipmi_ipmb_addr *ipmb;
        int                   j;

        if (intf->intf_num == -1)
            /* Interface was not ready yet. */
            continue;

        /*
         * intf_num is used as an marker to tell if the
         * interface is valid.  Thus we need a read barrier to
         * make sure data fetched before checking intf_num
         * won't be used.
         */
        smp_rmb();

        /*
         * First job here is to figure out where to send the
         * OEM events.  There's no way in IPMI to send OEM
         * events using an event send command, so we have to
         * find the SEL to put them in and stick them in
         * there.
         */

        /* Get capabilities from the get device id. */
        intf->local_sel_device = 0;
        intf->local_event_generator = 0;
        intf->event_receiver = 0;

        /* Request the device info from the local MC. */
        msg.netfn = IPMI_NETFN_APP_REQUEST;
        msg.cmd = IPMI_GET_DEVICE_ID_CMD;
        msg.data = NULL;
        msg.data_len = 0;
        intf->null_user_handler = device_id_fetcher;
        ipmi_panic_request_and_wait(intf, &addr, &msg);

        if (intf->local_event_generator) {
            /* Request the event receiver from the local MC. */
            msg.netfn = IPMI_NETFN_SENSOR_EVENT_REQUEST;
            msg.cmd = IPMI_GET_EVENT_RECEIVER_CMD;
            msg.data = NULL;
            msg.data_len = 0;
            intf->null_user_handler = event_receiver_fetcher;
            ipmi_panic_request_and_wait(intf, &addr, &msg);
        }
        intf->null_user_handler = NULL;

        /*
         * Validate the event receiver.  The low bit must not
         * be 1 (it must be a valid IPMB address), it cannot
         * be zero, and it must not be my address.
         */
        if (((intf->event_receiver & 1) == 0)
            && (intf->event_receiver != 0)
            && (intf->event_receiver != intf->channels[0].address)) {
            /*
             * The event receiver is valid, send an IPMB
             * message.
             */
            ipmb = (struct ipmi_ipmb_addr *) &addr;
            ipmb->addr_type = IPMI_IPMB_ADDR_TYPE;
            ipmb->channel = 0; /* FIXME - is this right? */
            ipmb->lun = intf->event_receiver_lun;
            ipmb->slave_addr = intf->event_receiver;
        } else if (intf->local_sel_device) {
            /*
             * The event receiver was not valid (or was
             * me), but I am an SEL device, just dump it
             * in my SEL.
             */
            si = (struct ipmi_system_interface_addr *) &addr;
            si->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
            si->channel = IPMI_BMC_CHANNEL;
            si->lun = 0;
        } else
            continue; /* No where to send the event. */

        msg.netfn = IPMI_NETFN_STORAGE_REQUEST; /* Storage. */
        msg.cmd = IPMI_ADD_SEL_ENTRY_CMD;
        msg.data = data;
        msg.data_len = 16;

        j = 0;
        while (*p) {
            int size = strlen(p);

            if (size > 11)
                size = 11;
            data[0] = 0;
            data[1] = 0;
            data[2] = 0xf0; /* OEM event without timestamp. */
            data[3] = intf->channels[0].address;
            data[4] = j++; /* sequence # */
            /*
             * Always give 11 bytes, so strncpy will fill
             * it with zeroes for me.
             */
            strncpy(data+5, p, 11);
            p += size;

            ipmi_panic_request_and_wait(intf, &addr, &msg);
        }
    }
#endif /* CONFIG_IPMI_PANIC_STRING */
}
#endif /* CONFIG_IPMI_PANIC_EVENT */

static int has_panicked;

static int panic_event(struct notifier_block *this,
               unsigned long         event,
               void                  *ptr)
{
    ipmi_smi_t intf;

    if (has_panicked)
        return NOTIFY_DONE;
    has_panicked = 1;

    /* For every registered interface, set it to run to completion. */
    list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
        if (!intf->handlers)
            /* Interface is not ready. */
            continue;

        intf->run_to_completion = 1;
        intf->handlers->set_run_to_completion(intf->send_info, 1);
    }

#ifdef CONFIG_IPMI_PANIC_EVENT
    send_panic_events(ptr);
#endif

    return NOTIFY_DONE;
}

static struct notifier_block panic_block = {
    .notifier_call  = panic_event,
    .next       = NULL,
    .priority   = 200   /* priority: INT_MAX >= x >= 0 */
};

static int ipmi_init_msghandler(void)
{
    int rv;

    if (initialized)
        return 0;

    rv = driver_register(&ipmidriver.driver);
    if (rv) {
        printk(KERN_ERR PFX "Could not register IPMI driver\n");
        return rv;
    }

    printk(KERN_INFO "ipmi message handler version "
           IPMI_DRIVER_VERSION "\n");

#ifdef CONFIG_PROC_FS
    proc_ipmi_root = proc_mkdir("ipmi", NULL);
    if (!proc_ipmi_root) {
        printk(KERN_ERR PFX "Unable to create IPMI proc dir");
        return -ENOMEM;
    }

#endif /* CONFIG_PROC_FS */

    setup_timer(&ipmi_timer, ipmi_timeout, 0);
    mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);

    atomic_notifier_chain_register(&panic_notifier_list, &panic_block);

    initialized = 1;

    return 0;
}

static int __init ipmi_init_msghandler_mod(void)
{
    ipmi_init_msghandler();
    return 0;
}

static void __exit cleanup_ipmi(void)
{
    int count;

    if (!initialized)
        return;

    atomic_notifier_chain_unregister(&panic_notifier_list, &panic_block);

    /*
     * This can't be called if any interfaces exist, so no worry
     * about shutting down the interfaces.
     */

    /*
     * Tell the timer to stop, then wait for it to stop.  This
     * avoids problems with race conditions removing the timer
     * here.
     */
    atomic_inc(&stop_operation);
    del_timer_sync(&ipmi_timer);

#ifdef CONFIG_PROC_FS
    remove_proc_entry(proc_ipmi_root->name, NULL);
#endif /* CONFIG_PROC_FS */

    driver_unregister(&ipmidriver.driver);

    initialized = 0;

    /* Check for buffer leaks. */
    count = atomic_read(&smi_msg_inuse_count);
    if (count != 0)
        printk(KERN_WARNING PFX "SMI message count %d at exit\n",
               count);
    count = atomic_read(&recv_msg_inuse_count);
    if (count != 0)
        printk(KERN_WARNING PFX "recv message count %d at exit\n",
               count);
}
module_exit(cleanup_ipmi);

module_init(ipmi_init_msghandler_mod);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Corey Minyard <[email protected]>");
MODULE_DESCRIPTION("Incoming and outgoing message routing for an IPMI"
           " interface.");
MODULE_VERSION(IPMI_DRIVER_VERSION);