OSCL-LXR linux-6.0.1/​drivers/​char/​ipmi/​ipmi_si_intf.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * ipmi_si.c
  *
  * The interface to the IPMI driver for the system interfaces (KCS, SMIC,
  * BT).
  *
  * Author: MontaVista Software, Inc.
  *         Corey Minyard <minyard@mvista.com>
  *         source@mvista.com
  *
  * Copyright 2002 MontaVista Software Inc.
  * Copyright 2006 IBM Corp., Christian Krafft <krafft@de.ibm.com>
  */
 
 /*
  * This file holds the "policy" for the interface to the SMI state
  * machine.  It does the configuration, handles timers and interrupts,
  * and drives the real SMI state machine.
  */
 
 #define pr_fmt(fmt) "ipmi_si: " fmt
 
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/timer.h>
 #include <linux/errno.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/list.h>
 #include <linux/notifier.h>
 #include <linux/mutex.h>
 #include <linux/kthread.h>
 #include <asm/irq.h>
 #include <linux/interrupt.h>
 #include <linux/rcupdate.h>
 #include <linux/ipmi.h>
 #include <linux/ipmi_smi.h>
 #include "ipmi_si.h"
 #include "ipmi_si_sm.h"
 #include <linux/string.h>
 #include <linux/ctype.h>
 
 /* Measure times between events in the driver. */
 #undef DEBUG_TIMING
 
 /* Call every 10 ms. */
 #define SI_TIMEOUT_TIME_USEC    10000
 #define SI_USEC_PER_JIFFY   (1000000/HZ)
 #define SI_TIMEOUT_JIFFIES  (SI_TIMEOUT_TIME_USEC/SI_USEC_PER_JIFFY)
 #define SI_SHORT_TIMEOUT_USEC  250 /* .25ms when the SM request a
                       short timeout */
 
 enum si_intf_state {
     SI_NORMAL,
     SI_GETTING_FLAGS,
     SI_GETTING_EVENTS,
     SI_CLEARING_FLAGS,
     SI_GETTING_MESSAGES,
     SI_CHECKING_ENABLES,
     SI_SETTING_ENABLES
     /* FIXME - add watchdog stuff. */
 };
 
 /* Some BT-specific defines we need here. */
 #define IPMI_BT_INTMASK_REG     2
 #define IPMI_BT_INTMASK_CLEAR_IRQ_BIT   2
 #define IPMI_BT_INTMASK_ENABLE_IRQ_BIT  1
 
 /* 'invalid' to allow a firmware-specified interface to be disabled */
 const char *const si_to_str[] = { "invalid", "kcs", "smic", "bt", NULL };
 
 static bool initialized;
 
 /*
  * Indexes into stats[] in smi_info below.
  */
 enum si_stat_indexes {
     /*
      * Number of times the driver requested a timer while an operation
      * was in progress.
      */
     SI_STAT_short_timeouts = 0,
 
     /*
      * Number of times the driver requested a timer while nothing was in
      * progress.
      */
     SI_STAT_long_timeouts,
 
     /* Number of times the interface was idle while being polled. */
     SI_STAT_idles,
 
     /* Number of interrupts the driver handled. */
     SI_STAT_interrupts,
 
     /* Number of time the driver got an ATTN from the hardware. */
     SI_STAT_attentions,
 
     /* Number of times the driver requested flags from the hardware. */
     SI_STAT_flag_fetches,
 
     /* Number of times the hardware didn't follow the state machine. */
     SI_STAT_hosed_count,
 
     /* Number of completed messages. */
     SI_STAT_complete_transactions,
 
     /* Number of IPMI events received from the hardware. */
     SI_STAT_events,
 
     /* Number of watchdog pretimeouts. */
     SI_STAT_watchdog_pretimeouts,
 
     /* Number of asynchronous messages received. */
     SI_STAT_incoming_messages,
 
 
     /* This *must* remain last, add new values above this. */
     SI_NUM_STATS
 };
 
 struct smi_info {
     int                    si_num;
     struct ipmi_smi        *intf;
     struct si_sm_data      *si_sm;
     const struct si_sm_handlers *handlers;
     spinlock_t             si_lock;
     struct ipmi_smi_msg    *waiting_msg;
     struct ipmi_smi_msg    *curr_msg;
     enum si_intf_state     si_state;
 
     /*
      * Used to handle the various types of I/O that can occur with
      * IPMI
      */
     struct si_sm_io io;
 
     /*
      * Per-OEM handler, called from handle_flags().  Returns 1
      * when handle_flags() needs to be re-run or 0 indicating it
      * set si_state itself.
      */
     int (*oem_data_avail_handler)(struct smi_info *smi_info);
 
     /*
      * Flags from the last GET_MSG_FLAGS command, used when an ATTN
      * is set to hold the flags until we are done handling everything
      * from the flags.
      */
 #define RECEIVE_MSG_AVAIL   0x01
 #define EVENT_MSG_BUFFER_FULL   0x02
 #define WDT_PRE_TIMEOUT_INT 0x08
 #define OEM0_DATA_AVAIL     0x20
 #define OEM1_DATA_AVAIL     0x40
 #define OEM2_DATA_AVAIL     0x80
 #define OEM_DATA_AVAIL      (OEM0_DATA_AVAIL | \
                  OEM1_DATA_AVAIL | \
                  OEM2_DATA_AVAIL)
     unsigned char       msg_flags;
 
     /* Does the BMC have an event buffer? */
     bool            has_event_buffer;
 
     /*
      * If set to true, this will request events the next time the
      * state machine is idle.
      */
     atomic_t            req_events;
 
     /*
      * If true, run the state machine to completion on every send
      * call.  Generally used after a panic to make sure stuff goes
      * out.
      */
     bool                run_to_completion;
 
     /* The timer for this si. */
     struct timer_list   si_timer;
 
     /* This flag is set, if the timer can be set */
     bool            timer_can_start;
 
     /* This flag is set, if the timer is running (timer_pending() isn't enough) */
     bool            timer_running;
 
     /* The time (in jiffies) the last timeout occurred at. */
     unsigned long       last_timeout_jiffies;
 
     /* Are we waiting for the events, pretimeouts, received msgs? */
     atomic_t            need_watch;
 
     /*
      * The driver will disable interrupts when it gets into a
      * situation where it cannot handle messages due to lack of
      * memory.  Once that situation clears up, it will re-enable
      * interrupts.
      */
     bool interrupt_disabled;
 
     /*
      * Does the BMC support events?
      */
     bool supports_event_msg_buff;
 
     /*
      * Can we disable interrupts the global enables receive irq
      * bit?  There are currently two forms of brokenness, some
      * systems cannot disable the bit (which is technically within
      * the spec but a bad idea) and some systems have the bit
      * forced to zero even though interrupts work (which is
      * clearly outside the spec).  The next bool tells which form
      * of brokenness is present.
      */
     bool cannot_disable_irq;
 
     /*
      * Some systems are broken and cannot set the irq enable
      * bit, even if they support interrupts.
      */
     bool irq_enable_broken;
 
     /* Is the driver in maintenance mode? */
     bool in_maintenance_mode;
 
     /*
      * Did we get an attention that we did not handle?
      */
     bool got_attn;
 
     /* From the get device id response... */
     struct ipmi_device_id device_id;
 
     /* Have we added the device group to the device? */
     bool dev_group_added;
 
     /* Counters and things for the proc filesystem. */
     atomic_t stats[SI_NUM_STATS];
 
     struct task_struct *thread;
 
     struct list_head link;
 };
 
 #define smi_inc_stat(smi, stat) \
     atomic_inc(&(smi)->stats[SI_STAT_ ## stat])
 #define smi_get_stat(smi, stat) \
     ((unsigned int) atomic_read(&(smi)->stats[SI_STAT_ ## stat]))
 
 #define IPMI_MAX_INTFS 4
 static int force_kipmid[IPMI_MAX_INTFS];
 static int num_force_kipmid;
 
 static unsigned int kipmid_max_busy_us[IPMI_MAX_INTFS];
 static int num_max_busy_us;
 
 static bool unload_when_empty = true;
 
 static int try_smi_init(struct smi_info *smi);
 static void cleanup_one_si(struct smi_info *smi_info);
 static void cleanup_ipmi_si(void);
 
 #ifdef DEBUG_TIMING
 void debug_timestamp(struct smi_info *smi_info, char *msg)
 {
     struct timespec64 t;
 
     ktime_get_ts64(&t);
     dev_dbg(smi_info->io.dev, "**%s: %lld.%9.9ld\n",
         msg, t.tv_sec, t.tv_nsec);
 }
 #else
 #define debug_timestamp(smi_info, x)
 #endif
 
 static ATOMIC_NOTIFIER_HEAD(xaction_notifier_list);
 static int register_xaction_notifier(struct notifier_block *nb)
 {
     return atomic_notifier_chain_register(&xaction_notifier_list, nb);
 }
 
 static void deliver_recv_msg(struct smi_info *smi_info,
                  struct ipmi_smi_msg *msg)
 {
     /* Deliver the message to the upper layer. */
     ipmi_smi_msg_received(smi_info->intf, msg);
 }
 
 static void return_hosed_msg(struct smi_info *smi_info, int cCode)
 {
     struct ipmi_smi_msg *msg = smi_info->curr_msg;
 
     if (cCode < 0 || cCode > IPMI_ERR_UNSPECIFIED)
         cCode = IPMI_ERR_UNSPECIFIED;
     /* else use it as is */
 
     /* Make it a response */
     msg->rsp[0] = msg->data[0] | 4;
     msg->rsp[1] = msg->data[1];
     msg->rsp[2] = cCode;
     msg->rsp_size = 3;
 
     smi_info->curr_msg = NULL;
     deliver_recv_msg(smi_info, msg);
 }
 
 static enum si_sm_result start_next_msg(struct smi_info *smi_info)
 {
     int              rv;
 
     if (!smi_info->waiting_msg) {
         smi_info->curr_msg = NULL;
         rv = SI_SM_IDLE;
     } else {
         int err;
 
         smi_info->curr_msg = smi_info->waiting_msg;
         smi_info->waiting_msg = NULL;
         debug_timestamp(smi_info, "Start2");
         err = atomic_notifier_call_chain(&xaction_notifier_list,
                 0, smi_info);
         if (err & NOTIFY_STOP_MASK) {
             rv = SI_SM_CALL_WITHOUT_DELAY;
             goto out;
         }
         err = smi_info->handlers->start_transaction(
             smi_info->si_sm,
             smi_info->curr_msg->data,
             smi_info->curr_msg->data_size);
         if (err)
             return_hosed_msg(smi_info, err);
 
         rv = SI_SM_CALL_WITHOUT_DELAY;
     }
 out:
     return rv;
 }
 
 static void smi_mod_timer(struct smi_info *smi_info, unsigned long new_val)
 {
     if (!smi_info->timer_can_start)
         return;
     smi_info->last_timeout_jiffies = jiffies;
     mod_timer(&smi_info->si_timer, new_val);
     smi_info->timer_running = true;
 }
 
 /*
  * Start a new message and (re)start the timer and thread.
  */
 static void start_new_msg(struct smi_info *smi_info, unsigned char *msg,
               unsigned int size)
 {
     smi_mod_timer(smi_info, jiffies + SI_TIMEOUT_JIFFIES);
 
     if (smi_info->thread)
         wake_up_process(smi_info->thread);
 
     smi_info->handlers->start_transaction(smi_info->si_sm, msg, size);
 }
 
 static void start_check_enables(struct smi_info *smi_info)
 {
     unsigned char msg[2];
 
     msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
     msg[1] = IPMI_GET_BMC_GLOBAL_ENABLES_CMD;
 
     start_new_msg(smi_info, msg, 2);
     smi_info->si_state = SI_CHECKING_ENABLES;
 }
 
 static void start_clear_flags(struct smi_info *smi_info)
 {
     unsigned char msg[3];
 
     /* Make sure the watchdog pre-timeout flag is not set at startup. */
     msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
     msg[1] = IPMI_CLEAR_MSG_FLAGS_CMD;
     msg[2] = WDT_PRE_TIMEOUT_INT;
 
     start_new_msg(smi_info, msg, 3);
     smi_info->si_state = SI_CLEARING_FLAGS;
 }
 
 static void start_getting_msg_queue(struct smi_info *smi_info)
 {
     smi_info->curr_msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
     smi_info->curr_msg->data[1] = IPMI_GET_MSG_CMD;
     smi_info->curr_msg->data_size = 2;
 
     start_new_msg(smi_info, smi_info->curr_msg->data,
               smi_info->curr_msg->data_size);
     smi_info->si_state = SI_GETTING_MESSAGES;
 }
 
 static void start_getting_events(struct smi_info *smi_info)
 {
     smi_info->curr_msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
     smi_info->curr_msg->data[1] = IPMI_READ_EVENT_MSG_BUFFER_CMD;
     smi_info->curr_msg->data_size = 2;
 
     start_new_msg(smi_info, smi_info->curr_msg->data,
               smi_info->curr_msg->data_size);
     smi_info->si_state = SI_GETTING_EVENTS;
 }
 
 /*
  * When we have a situtaion where we run out of memory and cannot
  * allocate messages, we just leave them in the BMC and run the system
  * polled until we can allocate some memory.  Once we have some
  * memory, we will re-enable the interrupt.
  *
  * Note that we cannot just use disable_irq(), since the interrupt may
  * be shared.
  */
 static inline bool disable_si_irq(struct smi_info *smi_info)
 {
     if ((smi_info->io.irq) && (!smi_info->interrupt_disabled)) {
         smi_info->interrupt_disabled = true;
         start_check_enables(smi_info);
         return true;
     }
     return false;
 }
 
 static inline bool enable_si_irq(struct smi_info *smi_info)
 {
     if ((smi_info->io.irq) && (smi_info->interrupt_disabled)) {
         smi_info->interrupt_disabled = false;
         start_check_enables(smi_info);
         return true;
     }
     return false;
 }
 
 /*
  * Allocate a message.  If unable to allocate, start the interrupt
  * disable process and return NULL.  If able to allocate but
  * interrupts are disabled, free the message and return NULL after
  * starting the interrupt enable process.
  */
 static struct ipmi_smi_msg *alloc_msg_handle_irq(struct smi_info *smi_info)
 {
     struct ipmi_smi_msg *msg;
 
     msg = ipmi_alloc_smi_msg();
     if (!msg) {
         if (!disable_si_irq(smi_info))
             smi_info->si_state = SI_NORMAL;
     } else if (enable_si_irq(smi_info)) {
         ipmi_free_smi_msg(msg);
         msg = NULL;
     }
     return msg;
 }
 
 static void handle_flags(struct smi_info *smi_info)
 {
 retry:
     if (smi_info->msg_flags & WDT_PRE_TIMEOUT_INT) {
         /* Watchdog pre-timeout */
         smi_inc_stat(smi_info, watchdog_pretimeouts);
 
         start_clear_flags(smi_info);
         smi_info->msg_flags &= ~WDT_PRE_TIMEOUT_INT;
         ipmi_smi_watchdog_pretimeout(smi_info->intf);
     } else if (smi_info->msg_flags & RECEIVE_MSG_AVAIL) {
         /* Messages available. */
         smi_info->curr_msg = alloc_msg_handle_irq(smi_info);
         if (!smi_info->curr_msg)
             return;
 
         start_getting_msg_queue(smi_info);
     } else if (smi_info->msg_flags & EVENT_MSG_BUFFER_FULL) {
         /* Events available. */
         smi_info->curr_msg = alloc_msg_handle_irq(smi_info);
         if (!smi_info->curr_msg)
             return;
 
         start_getting_events(smi_info);
     } else if (smi_info->msg_flags & OEM_DATA_AVAIL &&
            smi_info->oem_data_avail_handler) {
         if (smi_info->oem_data_avail_handler(smi_info))
             goto retry;
     } else
         smi_info->si_state = SI_NORMAL;
 }
 
 /*
  * Global enables we care about.
  */
 #define GLOBAL_ENABLES_MASK (IPMI_BMC_EVT_MSG_BUFF | IPMI_BMC_RCV_MSG_INTR | \
                  IPMI_BMC_EVT_MSG_INTR)
 
 static u8 current_global_enables(struct smi_info *smi_info, u8 base,
                  bool *irq_on)
 {
     u8 enables = 0;
 
     if (smi_info->supports_event_msg_buff)
         enables |= IPMI_BMC_EVT_MSG_BUFF;
 
     if (((smi_info->io.irq && !smi_info->interrupt_disabled) ||
          smi_info->cannot_disable_irq) &&
         !smi_info->irq_enable_broken)
         enables |= IPMI_BMC_RCV_MSG_INTR;
 
     if (smi_info->supports_event_msg_buff &&
         smi_info->io.irq && !smi_info->interrupt_disabled &&
         !smi_info->irq_enable_broken)
         enables |= IPMI_BMC_EVT_MSG_INTR;
 
     *irq_on = enables & (IPMI_BMC_EVT_MSG_INTR | IPMI_BMC_RCV_MSG_INTR);
 
     return enables;
 }
 
 static void check_bt_irq(struct smi_info *smi_info, bool irq_on)
 {
     u8 irqstate = smi_info->io.inputb(&smi_info->io, IPMI_BT_INTMASK_REG);
 
     irqstate &= IPMI_BT_INTMASK_ENABLE_IRQ_BIT;
 
     if ((bool)irqstate == irq_on)
         return;
 
     if (irq_on)
         smi_info->io.outputb(&smi_info->io, IPMI_BT_INTMASK_REG,
                      IPMI_BT_INTMASK_ENABLE_IRQ_BIT);
     else
         smi_info->io.outputb(&smi_info->io, IPMI_BT_INTMASK_REG, 0);
 }
 
 static void handle_transaction_done(struct smi_info *smi_info)
 {
     struct ipmi_smi_msg *msg;
 
     debug_timestamp(smi_info, "Done");
     switch (smi_info->si_state) {
     case SI_NORMAL:
         if (!smi_info->curr_msg)
             break;
 
         smi_info->curr_msg->rsp_size
             = smi_info->handlers->get_result(
                 smi_info->si_sm,
                 smi_info->curr_msg->rsp,
                 IPMI_MAX_MSG_LENGTH);
 
         /*
          * Do this here becase deliver_recv_msg() releases the
          * lock, and a new message can be put in during the
          * time the lock is released.
          */
         msg = smi_info->curr_msg;
         smi_info->curr_msg = NULL;
         deliver_recv_msg(smi_info, msg);
         break;
 
     case SI_GETTING_FLAGS:
     {
         unsigned char msg[4];
         unsigned int  len;
 
         /* We got the flags from the SMI, now handle them. */
         len = smi_info->handlers->get_result(smi_info->si_sm, msg, 4);
         if (msg[2] != 0) {
             /* Error fetching flags, just give up for now. */
             smi_info->si_state = SI_NORMAL;
         } else if (len < 4) {
             /*
              * Hmm, no flags.  That's technically illegal, but
              * don't use uninitialized data.
              */
             smi_info->si_state = SI_NORMAL;
         } else {
             smi_info->msg_flags = msg[3];
             handle_flags(smi_info);
         }
         break;
     }
 
     case SI_CLEARING_FLAGS:
     {
         unsigned char msg[3];
 
         /* We cleared the flags. */
         smi_info->handlers->get_result(smi_info->si_sm, msg, 3);
         if (msg[2] != 0) {
             /* Error clearing flags */
             dev_warn_ratelimited(smi_info->io.dev,
                  "Error clearing flags: %2.2x\n", msg[2]);
         }
         smi_info->si_state = SI_NORMAL;
         break;
     }
 
     case SI_GETTING_EVENTS:
     {
         smi_info->curr_msg->rsp_size
             = smi_info->handlers->get_result(
                 smi_info->si_sm,
                 smi_info->curr_msg->rsp,
                 IPMI_MAX_MSG_LENGTH);
 
         /*
          * Do this here becase deliver_recv_msg() releases the
          * lock, and a new message can be put in during the
          * time the lock is released.
          */
         msg = smi_info->curr_msg;
         smi_info->curr_msg = NULL;
         if (msg->rsp[2] != 0) {
             /* Error getting event, probably done. */
             msg->done(msg);
 
             /* Take off the event flag. */
             smi_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
             handle_flags(smi_info);
         } else {
             smi_inc_stat(smi_info, events);
 
             /*
              * Do this before we deliver the message
              * because delivering the message releases the
              * lock and something else can mess with the
              * state.
              */
             handle_flags(smi_info);
 
             deliver_recv_msg(smi_info, msg);
         }
         break;
     }
 
     case SI_GETTING_MESSAGES:
     {
         smi_info->curr_msg->rsp_size
             = smi_info->handlers->get_result(
                 smi_info->si_sm,
                 smi_info->curr_msg->rsp,
                 IPMI_MAX_MSG_LENGTH);
 
         /*
          * Do this here becase deliver_recv_msg() releases the
          * lock, and a new message can be put in during the
          * time the lock is released.
          */
         msg = smi_info->curr_msg;
         smi_info->curr_msg = NULL;
         if (msg->rsp[2] != 0) {
             /* Error getting event, probably done. */
             msg->done(msg);
 
             /* Take off the msg flag. */
             smi_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
             handle_flags(smi_info);
         } else {
             smi_inc_stat(smi_info, incoming_messages);
 
             /*
              * Do this before we deliver the message
              * because delivering the message releases the
              * lock and something else can mess with the
              * state.
              */
             handle_flags(smi_info);
 
             deliver_recv_msg(smi_info, msg);
         }
         break;
     }
 
     case SI_CHECKING_ENABLES:
     {
         unsigned char msg[4];
         u8 enables;
         bool irq_on;
 
         /* We got the flags from the SMI, now handle them. */
         smi_info->handlers->get_result(smi_info->si_sm, msg, 4);
         if (msg[2] != 0) {
             dev_warn_ratelimited(smi_info->io.dev,
                 "Couldn't get irq info: %x,\n"
                 "Maybe ok, but ipmi might run very slowly.\n",
                 msg[2]);
             smi_info->si_state = SI_NORMAL;
             break;
         }
         enables = current_global_enables(smi_info, 0, &irq_on);
         if (smi_info->io.si_type == SI_BT)
             /* BT has its own interrupt enable bit. */
             check_bt_irq(smi_info, irq_on);
         if (enables != (msg[3] & GLOBAL_ENABLES_MASK)) {
             /* Enables are not correct, fix them. */
             msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
             msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
             msg[2] = enables | (msg[3] & ~GLOBAL_ENABLES_MASK);
             smi_info->handlers->start_transaction(
                 smi_info->si_sm, msg, 3);
             smi_info->si_state = SI_SETTING_ENABLES;
         } else if (smi_info->supports_event_msg_buff) {
             smi_info->curr_msg = ipmi_alloc_smi_msg();
             if (!smi_info->curr_msg) {
                 smi_info->si_state = SI_NORMAL;
                 break;
             }
             start_getting_events(smi_info);
         } else {
             smi_info->si_state = SI_NORMAL;
         }
         break;
     }
 
     case SI_SETTING_ENABLES:
     {
         unsigned char msg[4];
 
         smi_info->handlers->get_result(smi_info->si_sm, msg, 4);
         if (msg[2] != 0)
             dev_warn_ratelimited(smi_info->io.dev,
                  "Could not set the global enables: 0x%x.\n",
                  msg[2]);
 
         if (smi_info->supports_event_msg_buff) {
             smi_info->curr_msg = ipmi_alloc_smi_msg();
             if (!smi_info->curr_msg) {
                 smi_info->si_state = SI_NORMAL;
                 break;
             }
             start_getting_events(smi_info);
         } else {
             smi_info->si_state = SI_NORMAL;
         }
         break;
     }
     }
 }
 
 /*
  * Called on timeouts and events.  Timeouts should pass the elapsed
  * time, interrupts should pass in zero.  Must be called with
  * si_lock held and interrupts disabled.
  */
 static enum si_sm_result smi_event_handler(struct smi_info *smi_info,
                        int time)
 {
     enum si_sm_result si_sm_result;
 
 restart:
     /*
      * There used to be a loop here that waited a little while
      * (around 25us) before giving up.  That turned out to be
      * pointless, the minimum delays I was seeing were in the 300us
      * range, which is far too long to wait in an interrupt.  So
      * we just run until the state machine tells us something
      * happened or it needs a delay.
      */
     si_sm_result = smi_info->handlers->event(smi_info->si_sm, time);
     time = 0;
     while (si_sm_result == SI_SM_CALL_WITHOUT_DELAY)
         si_sm_result = smi_info->handlers->event(smi_info->si_sm, 0);
 
     if (si_sm_result == SI_SM_TRANSACTION_COMPLETE) {
         smi_inc_stat(smi_info, complete_transactions);
 
         handle_transaction_done(smi_info);
         goto restart;
     } else if (si_sm_result == SI_SM_HOSED) {
         smi_inc_stat(smi_info, hosed_count);
 
         /*
          * Do the before return_hosed_msg, because that
          * releases the lock.
          */
         smi_info->si_state = SI_NORMAL;
         if (smi_info->curr_msg != NULL) {
             /*
              * If we were handling a user message, format
              * a response to send to the upper layer to
              * tell it about the error.
              */
             return_hosed_msg(smi_info, IPMI_ERR_UNSPECIFIED);
         }
         goto restart;
     }
 
     /*
      * We prefer handling attn over new messages.  But don't do
      * this if there is not yet an upper layer to handle anything.
      */
     if (si_sm_result == SI_SM_ATTN || smi_info->got_attn) {
         unsigned char msg[2];
 
         if (smi_info->si_state != SI_NORMAL) {
             /*
              * We got an ATTN, but we are doing something else.
              * Handle the ATTN later.
              */
             smi_info->got_attn = true;
         } else {
             smi_info->got_attn = false;
             smi_inc_stat(smi_info, attentions);
 
             /*
              * Got a attn, send down a get message flags to see
              * what's causing it.  It would be better to handle
              * this in the upper layer, but due to the way
              * interrupts work with the SMI, that's not really
              * possible.
              */
             msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
             msg[1] = IPMI_GET_MSG_FLAGS_CMD;
 
             start_new_msg(smi_info, msg, 2);
             smi_info->si_state = SI_GETTING_FLAGS;
             goto restart;
         }
     }
 
     /* If we are currently idle, try to start the next message. */
     if (si_sm_result == SI_SM_IDLE) {
         smi_inc_stat(smi_info, idles);
 
         si_sm_result = start_next_msg(smi_info);
         if (si_sm_result != SI_SM_IDLE)
             goto restart;
     }
 
     if ((si_sm_result == SI_SM_IDLE)
         && (atomic_read(&smi_info->req_events))) {
         /*
          * We are idle and the upper layer requested that I fetch
          * events, so do so.
          */
         atomic_set(&smi_info->req_events, 0);
 
         /*
          * Take this opportunity to check the interrupt and
          * message enable state for the BMC.  The BMC can be
          * asynchronously reset, and may thus get interrupts
          * disable and messages disabled.
          */
         if (smi_info->supports_event_msg_buff || smi_info->io.irq) {
             start_check_enables(smi_info);
         } else {
             smi_info->curr_msg = alloc_msg_handle_irq(smi_info);
             if (!smi_info->curr_msg)
                 goto out;
 
             start_getting_events(smi_info);
         }
         goto restart;
     }
 
     if (si_sm_result == SI_SM_IDLE && smi_info->timer_running) {
         /* Ok it if fails, the timer will just go off. */
         if (del_timer(&smi_info->si_timer))
             smi_info->timer_running = false;
     }
 
 out:
     return si_sm_result;
 }
 
 static void check_start_timer_thread(struct smi_info *smi_info)
 {
     if (smi_info->si_state == SI_NORMAL && smi_info->curr_msg == NULL) {
         smi_mod_timer(smi_info, jiffies + SI_TIMEOUT_JIFFIES);
 
         if (smi_info->thread)
             wake_up_process(smi_info->thread);
 
         start_next_msg(smi_info);
         smi_event_handler(smi_info, 0);
     }
 }
 
 static void flush_messages(void *send_info)
 {
     struct smi_info *smi_info = send_info;
     enum si_sm_result result;
 
     /*
      * Currently, this function is called only in run-to-completion
      * mode.  This means we are single-threaded, no need for locks.
      */
     result = smi_event_handler(smi_info, 0);
     while (result != SI_SM_IDLE) {
         udelay(SI_SHORT_TIMEOUT_USEC);
         result = smi_event_handler(smi_info, SI_SHORT_TIMEOUT_USEC);
     }
 }
 
 static void sender(void                *send_info,
            struct ipmi_smi_msg *msg)
 {
     struct smi_info   *smi_info = send_info;
     unsigned long     flags;
 
     debug_timestamp(smi_info, "Enqueue");
 
     if (smi_info->run_to_completion) {
         /*
          * If we are running to completion, start it.  Upper
          * layer will call flush_messages to clear it out.
          */
         smi_info->waiting_msg = msg;
         return;
     }
 
     spin_lock_irqsave(&smi_info->si_lock, flags);
     /*
      * The following two lines don't need to be under the lock for
      * the lock's sake, but they do need SMP memory barriers to
      * avoid getting things out of order.  We are already claiming
      * the lock, anyway, so just do it under the lock to avoid the
      * ordering problem.
      */
     BUG_ON(smi_info->waiting_msg);
     smi_info->waiting_msg = msg;
     check_start_timer_thread(smi_info);
     spin_unlock_irqrestore(&smi_info->si_lock, flags);
 }
 
 static void set_run_to_completion(void *send_info, bool i_run_to_completion)
 {
     struct smi_info   *smi_info = send_info;
 
     smi_info->run_to_completion = i_run_to_completion;
     if (i_run_to_completion)
         flush_messages(smi_info);
 }
 
 /*
  * Use -1 as a special constant to tell that we are spinning in kipmid
  * looking for something and not delaying between checks
  */
 #define IPMI_TIME_NOT_BUSY ns_to_ktime(-1ull)
 static inline bool ipmi_thread_busy_wait(enum si_sm_result smi_result,
                      const struct smi_info *smi_info,
                      ktime_t *busy_until)
 {
     unsigned int max_busy_us = 0;
 
     if (smi_info->si_num < num_max_busy_us)
         max_busy_us = kipmid_max_busy_us[smi_info->si_num];
     if (max_busy_us == 0 || smi_result != SI_SM_CALL_WITH_DELAY)
         *busy_until = IPMI_TIME_NOT_BUSY;
     else if (*busy_until == IPMI_TIME_NOT_BUSY) {
         *busy_until = ktime_get() + max_busy_us * NSEC_PER_USEC;
     } else {
         if (unlikely(ktime_get() > *busy_until)) {
             *busy_until = IPMI_TIME_NOT_BUSY;
             return false;
         }
     }
     return true;
 }
 
 
 /*
  * A busy-waiting loop for speeding up IPMI operation.
  *
  * Lousy hardware makes this hard.  This is only enabled for systems
  * that are not BT and do not have interrupts.  It starts spinning
  * when an operation is complete or until max_busy tells it to stop
  * (if that is enabled).  See the paragraph on kimid_max_busy_us in
  * Documentation/driver-api/ipmi.rst for details.
  */
 static int ipmi_thread(void *data)
 {
     struct smi_info *smi_info = data;
     unsigned long flags;
     enum si_sm_result smi_result;
     ktime_t busy_until = IPMI_TIME_NOT_BUSY;
 
     set_user_nice(current, MAX_NICE);
     while (!kthread_should_stop()) {
         int busy_wait;
 
         spin_lock_irqsave(&(smi_info->si_lock), flags);
         smi_result = smi_event_handler(smi_info, 0);
 
         /*
          * If the driver is doing something, there is a possible
          * race with the timer.  If the timer handler see idle,
          * and the thread here sees something else, the timer
          * handler won't restart the timer even though it is
          * required.  So start it here if necessary.
          */
         if (smi_result != SI_SM_IDLE && !smi_info->timer_running)
             smi_mod_timer(smi_info, jiffies + SI_TIMEOUT_JIFFIES);
 
         spin_unlock_irqrestore(&(smi_info->si_lock), flags);
         busy_wait = ipmi_thread_busy_wait(smi_result, smi_info,
                           &busy_until);
         if (smi_result == SI_SM_CALL_WITHOUT_DELAY) {
             ; /* do nothing */
         } else if (smi_result == SI_SM_CALL_WITH_DELAY && busy_wait) {
             /*
              * In maintenance mode we run as fast as
              * possible to allow firmware updates to
              * complete as fast as possible, but normally
              * don't bang on the scheduler.
              */
             if (smi_info->in_maintenance_mode)
                 schedule();
             else
                 usleep_range(100, 200);
         } else if (smi_result == SI_SM_IDLE) {
             if (atomic_read(&smi_info->need_watch)) {
                 schedule_timeout_interruptible(100);
             } else {
                 /* Wait to be woken up when we are needed. */
                 __set_current_state(TASK_INTERRUPTIBLE);
                 schedule();
             }
         } else {
             schedule_timeout_interruptible(1);
         }
     }
     return 0;
 }
 
 
 static void poll(void *send_info)
 {
     struct smi_info *smi_info = send_info;
     unsigned long flags = 0;
     bool run_to_completion = smi_info->run_to_completion;
 
     /*
      * Make sure there is some delay in the poll loop so we can
      * drive time forward and timeout things.
      */
     udelay(10);
     if (!run_to_completion)
         spin_lock_irqsave(&smi_info->si_lock, flags);
     smi_event_handler(smi_info, 10);
     if (!run_to_completion)
         spin_unlock_irqrestore(&smi_info->si_lock, flags);
 }
 
 static void request_events(void *send_info)
 {
     struct smi_info *smi_info = send_info;
 
     if (!smi_info->has_event_buffer)
         return;
 
     atomic_set(&smi_info->req_events, 1);
 }
 
 static void set_need_watch(void *send_info, unsigned int watch_mask)
 {
     struct smi_info *smi_info = send_info;
     unsigned long flags;
     int enable;
 
     enable = !!watch_mask;
 
     atomic_set(&smi_info->need_watch, enable);
     spin_lock_irqsave(&smi_info->si_lock, flags);
     check_start_timer_thread(smi_info);
     spin_unlock_irqrestore(&smi_info->si_lock, flags);
 }
 
 static void smi_timeout(struct timer_list *t)
 {
     struct smi_info   *smi_info = from_timer(smi_info, t, si_timer);
     enum si_sm_result smi_result;
     unsigned long     flags;
     unsigned long     jiffies_now;
     long              time_diff;
     long          timeout;
 
     spin_lock_irqsave(&(smi_info->si_lock), flags);
     debug_timestamp(smi_info, "Timer");
 
     jiffies_now = jiffies;
     time_diff = (((long)jiffies_now - (long)smi_info->last_timeout_jiffies)
              * SI_USEC_PER_JIFFY);
     smi_result = smi_event_handler(smi_info, time_diff);
 
     if ((smi_info->io.irq) && (!smi_info->interrupt_disabled)) {
         /* Running with interrupts, only do long timeouts. */
         timeout = jiffies + SI_TIMEOUT_JIFFIES;
         smi_inc_stat(smi_info, long_timeouts);
         goto do_mod_timer;
     }
 
     /*
      * If the state machine asks for a short delay, then shorten
      * the timer timeout.
      */
     if (smi_result == SI_SM_CALL_WITH_DELAY) {
         smi_inc_stat(smi_info, short_timeouts);
         timeout = jiffies + 1;
     } else {
         smi_inc_stat(smi_info, long_timeouts);
         timeout = jiffies + SI_TIMEOUT_JIFFIES;
     }
 
 do_mod_timer:
     if (smi_result != SI_SM_IDLE)
         smi_mod_timer(smi_info, timeout);
     else
         smi_info->timer_running = false;
     spin_unlock_irqrestore(&(smi_info->si_lock), flags);
 }
 
 irqreturn_t ipmi_si_irq_handler(int irq, void *data)
 {
     struct smi_info *smi_info = data;
     unsigned long   flags;
 
     if (smi_info->io.si_type == SI_BT)
         /* We need to clear the IRQ flag for the BT interface. */
         smi_info->io.outputb(&smi_info->io, IPMI_BT_INTMASK_REG,
                      IPMI_BT_INTMASK_CLEAR_IRQ_BIT
                      | IPMI_BT_INTMASK_ENABLE_IRQ_BIT);
 
     spin_lock_irqsave(&(smi_info->si_lock), flags);
 
     smi_inc_stat(smi_info, interrupts);
 
     debug_timestamp(smi_info, "Interrupt");
 
     smi_event_handler(smi_info, 0);
     spin_unlock_irqrestore(&(smi_info->si_lock), flags);
     return IRQ_HANDLED;
 }
 
 static int smi_start_processing(void            *send_info,
                 struct ipmi_smi *intf)
 {
     struct smi_info *new_smi = send_info;
     int             enable = 0;
 
     new_smi->intf = intf;
 
     /* Set up the timer that drives the interface. */
     timer_setup(&new_smi->si_timer, smi_timeout, 0);
     new_smi->timer_can_start = true;
     smi_mod_timer(new_smi, jiffies + SI_TIMEOUT_JIFFIES);
 
     /* Try to claim any interrupts. */
     if (new_smi->io.irq_setup) {
         new_smi->io.irq_handler_data = new_smi;
         new_smi->io.irq_setup(&new_smi->io);
     }
 
     /*
      * Check if the user forcefully enabled the daemon.
      */
     if (new_smi->si_num < num_force_kipmid)
         enable = force_kipmid[new_smi->si_num];
     /*
      * The BT interface is efficient enough to not need a thread,
      * and there is no need for a thread if we have interrupts.
      */
     else if ((new_smi->io.si_type != SI_BT) && (!new_smi->io.irq))
         enable = 1;
 
     if (enable) {
         new_smi->thread = kthread_run(ipmi_thread, new_smi,
                           "kipmi%d", new_smi->si_num);
         if (IS_ERR(new_smi->thread)) {
             dev_notice(new_smi->io.dev,
                    "Could not start kernel thread due to error %ld, only using timers to drive the interface\n",
                    PTR_ERR(new_smi->thread));
             new_smi->thread = NULL;
         }
     }
 
     return 0;
 }
 
 static int get_smi_info(void *send_info, struct ipmi_smi_info *data)
 {
     struct smi_info *smi = send_info;
 
     data->addr_src = smi->io.addr_source;
     data->dev = smi->io.dev;
     data->addr_info = smi->io.addr_info;
     get_device(smi->io.dev);
 
     return 0;
 }
 
 static void set_maintenance_mode(void *send_info, bool enable)
 {
     struct smi_info   *smi_info = send_info;
 
     if (!enable)
         atomic_set(&smi_info->req_events, 0);
     smi_info->in_maintenance_mode = enable;
 }
 
 static void shutdown_smi(void *send_info);
 static const struct ipmi_smi_handlers handlers = {
     .owner                  = THIS_MODULE,
     .start_processing       = smi_start_processing,
     .shutdown               = shutdown_smi,
     .get_smi_info       = get_smi_info,
     .sender         = sender,
     .request_events     = request_events,
     .set_need_watch     = set_need_watch,
     .set_maintenance_mode   = set_maintenance_mode,
     .set_run_to_completion  = set_run_to_completion,
     .flush_messages     = flush_messages,
     .poll           = poll,
 };
 
 static LIST_HEAD(smi_infos);
 static DEFINE_MUTEX(smi_infos_lock);
 static int smi_num; /* Used to sequence the SMIs */
 
 static const char * const addr_space_to_str[] = { "i/o", "mem" };
 
 module_param_array(force_kipmid, int, &num_force_kipmid, 0);
 MODULE_PARM_DESC(force_kipmid,
          "Force the kipmi daemon to be enabled (1) or disabled(0).  Normally the IPMI driver auto-detects this, but the value may be overridden by this parm.");
 module_param(unload_when_empty, bool, 0);
 MODULE_PARM_DESC(unload_when_empty,
          "Unload the module if no interfaces are specified or found, default is 1.  Setting to 0 is useful for hot add of devices using hotmod.");
 module_param_array(kipmid_max_busy_us, uint, &num_max_busy_us, 0644);
 MODULE_PARM_DESC(kipmid_max_busy_us,
          "Max time (in microseconds) to busy-wait for IPMI data before sleeping. 0 (default) means to wait forever. Set to 100-500 if kipmid is using up a lot of CPU time.");
 
 void ipmi_irq_finish_setup(struct si_sm_io *io)
 {
     if (io->si_type == SI_BT)
         /* Enable the interrupt in the BT interface. */
         io->outputb(io, IPMI_BT_INTMASK_REG,
                 IPMI_BT_INTMASK_ENABLE_IRQ_BIT);
 }
 
 void ipmi_irq_start_cleanup(struct si_sm_io *io)
 {
     if (io->si_type == SI_BT)
         /* Disable the interrupt in the BT interface. */
         io->outputb(io, IPMI_BT_INTMASK_REG, 0);
 }
 
 static void std_irq_cleanup(struct si_sm_io *io)
 {
     ipmi_irq_start_cleanup(io);
     free_irq(io->irq, io->irq_handler_data);
 }
 
 int ipmi_std_irq_setup(struct si_sm_io *io)
 {
     int rv;
 
     if (!io->irq)
         return 0;
 
     rv = request_irq(io->irq,
              ipmi_si_irq_handler,
              IRQF_SHARED,
              SI_DEVICE_NAME,
              io->irq_handler_data);
     if (rv) {
         dev_warn(io->dev, "%s unable to claim interrupt %d, running polled\n",
              SI_DEVICE_NAME, io->irq);
         io->irq = 0;
     } else {
         io->irq_cleanup = std_irq_cleanup;
         ipmi_irq_finish_setup(io);
         dev_info(io->dev, "Using irq %d\n", io->irq);
     }
 
     return rv;
 }
 
 static int wait_for_msg_done(struct smi_info *smi_info)
 {
     enum si_sm_result     smi_result;
 
     smi_result = smi_info->handlers->event(smi_info->si_sm, 0);
     for (;;) {
         if (smi_result == SI_SM_CALL_WITH_DELAY ||
             smi_result == SI_SM_CALL_WITH_TICK_DELAY) {
             schedule_timeout_uninterruptible(1);
             smi_result = smi_info->handlers->event(
                 smi_info->si_sm, jiffies_to_usecs(1));
         } else if (smi_result == SI_SM_CALL_WITHOUT_DELAY) {
             smi_result = smi_info->handlers->event(
                 smi_info->si_sm, 0);
         } else
             break;
     }
     if (smi_result == SI_SM_HOSED)
         /*
          * We couldn't get the state machine to run, so whatever's at
          * the port is probably not an IPMI SMI interface.
          */
         return -ENODEV;
 
     return 0;
 }
 
 static int try_get_dev_id(struct smi_info *smi_info)
 {
     unsigned char         msg[2];
     unsigned char         *resp;
     unsigned long         resp_len;
     int                   rv = 0;
     unsigned int          retry_count = 0;
 
     resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
     if (!resp)
         return -ENOMEM;
 
     /*
      * Do a Get Device ID command, since it comes back with some
      * useful info.
      */
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_GET_DEVICE_ID_CMD;
 
 retry:
     smi_info->handlers->start_transaction(smi_info->si_sm, msg, 2);
 
     rv = wait_for_msg_done(smi_info);
     if (rv)
         goto out;
 
     resp_len = smi_info->handlers->get_result(smi_info->si_sm,
                           resp, IPMI_MAX_MSG_LENGTH);
 
     /* Check and record info from the get device id, in case we need it. */
     rv = ipmi_demangle_device_id(resp[0] >> 2, resp[1],
             resp + 2, resp_len - 2, &smi_info->device_id);
     if (rv) {
         /* record completion code */
         unsigned char cc = *(resp + 2);
 
         if (cc != IPMI_CC_NO_ERROR &&
             ++retry_count <= GET_DEVICE_ID_MAX_RETRY) {
             dev_warn_ratelimited(smi_info->io.dev,
                 "BMC returned 0x%2.2x, retry get bmc device id\n",
                 cc);
             goto retry;
         }
     }
 
 out:
     kfree(resp);
     return rv;
 }
 
 static int get_global_enables(struct smi_info *smi_info, u8 *enables)
 {
     unsigned char         msg[3];
     unsigned char         *resp;
     unsigned long         resp_len;
     int                   rv;
 
     resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
     if (!resp)
         return -ENOMEM;
 
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_GET_BMC_GLOBAL_ENABLES_CMD;
     smi_info->handlers->start_transaction(smi_info->si_sm, msg, 2);
 
     rv = wait_for_msg_done(smi_info);
     if (rv) {
         dev_warn(smi_info->io.dev,
              "Error getting response from get global enables command: %d\n",
              rv);
         goto out;
     }
 
     resp_len = smi_info->handlers->get_result(smi_info->si_sm,
                           resp, IPMI_MAX_MSG_LENGTH);
 
     if (resp_len < 4 ||
             resp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2 ||
             resp[1] != IPMI_GET_BMC_GLOBAL_ENABLES_CMD   ||
             resp[2] != 0) {
         dev_warn(smi_info->io.dev,
              "Invalid return from get global enables command: %ld %x %x %x\n",
              resp_len, resp[0], resp[1], resp[2]);
         rv = -EINVAL;
         goto out;
     } else {
         *enables = resp[3];
     }
 
 out:
     kfree(resp);
     return rv;
 }
 
 /*
  * Returns 1 if it gets an error from the command.
  */
 static int set_global_enables(struct smi_info *smi_info, u8 enables)
 {
     unsigned char         msg[3];
     unsigned char         *resp;
     unsigned long         resp_len;
     int                   rv;
 
     resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
     if (!resp)
         return -ENOMEM;
 
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
     msg[2] = enables;
     smi_info->handlers->start_transaction(smi_info->si_sm, msg, 3);
 
     rv = wait_for_msg_done(smi_info);
     if (rv) {
         dev_warn(smi_info->io.dev,
              "Error getting response from set global enables command: %d\n",
              rv);
         goto out;
     }
 
     resp_len = smi_info->handlers->get_result(smi_info->si_sm,
                           resp, IPMI_MAX_MSG_LENGTH);
 
     if (resp_len < 3 ||
             resp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2 ||
             resp[1] != IPMI_SET_BMC_GLOBAL_ENABLES_CMD) {
         dev_warn(smi_info->io.dev,
              "Invalid return from set global enables command: %ld %x %x\n",
              resp_len, resp[0], resp[1]);
         rv = -EINVAL;
         goto out;
     }
 
     if (resp[2] != 0)
         rv = 1;
 
 out:
     kfree(resp);
     return rv;
 }
 
 /*
  * Some BMCs do not support clearing the receive irq bit in the global
  * enables (even if they don't support interrupts on the BMC).  Check
  * for this and handle it properly.
  */
 static void check_clr_rcv_irq(struct smi_info *smi_info)
 {
     u8 enables = 0;
     int rv;
 
     rv = get_global_enables(smi_info, &enables);
     if (!rv) {
         if ((enables & IPMI_BMC_RCV_MSG_INTR) == 0)
             /* Already clear, should work ok. */
             return;
 
         enables &= ~IPMI_BMC_RCV_MSG_INTR;
         rv = set_global_enables(smi_info, enables);
     }
 
     if (rv < 0) {
         dev_err(smi_info->io.dev,
             "Cannot check clearing the rcv irq: %d\n", rv);
         return;
     }
 
     if (rv) {
         /*
          * An error when setting the event buffer bit means
          * clearing the bit is not supported.
          */
         dev_warn(smi_info->io.dev,
              "The BMC does not support clearing the recv irq bit, compensating, but the BMC needs to be fixed.\n");
         smi_info->cannot_disable_irq = true;
     }
 }
 
 /*
  * Some BMCs do not support setting the interrupt bits in the global
  * enables even if they support interrupts.  Clearly bad, but we can
  * compensate.
  */
 static void check_set_rcv_irq(struct smi_info *smi_info)
 {
     u8 enables = 0;
     int rv;
 
     if (!smi_info->io.irq)
         return;
 
     rv = get_global_enables(smi_info, &enables);
     if (!rv) {
         enables |= IPMI_BMC_RCV_MSG_INTR;
         rv = set_global_enables(smi_info, enables);
     }
 
     if (rv < 0) {
         dev_err(smi_info->io.dev,
             "Cannot check setting the rcv irq: %d\n", rv);
         return;
     }
 
     if (rv) {
         /*
          * An error when setting the event buffer bit means
          * setting the bit is not supported.
          */
         dev_warn(smi_info->io.dev,
              "The BMC does not support setting the recv irq bit, compensating, but the BMC needs to be fixed.\n");
         smi_info->cannot_disable_irq = true;
         smi_info->irq_enable_broken = true;
     }
 }
 
 static int try_enable_event_buffer(struct smi_info *smi_info)
 {
     unsigned char         msg[3];
     unsigned char         *resp;
     unsigned long         resp_len;
     int                   rv = 0;
 
     resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
     if (!resp)
         return -ENOMEM;
 
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_GET_BMC_GLOBAL_ENABLES_CMD;
     smi_info->handlers->start_transaction(smi_info->si_sm, msg, 2);
 
     rv = wait_for_msg_done(smi_info);
     if (rv) {
         pr_warn("Error getting response from get global enables command, the event buffer is not enabled\n");
         goto out;
     }
 
     resp_len = smi_info->handlers->get_result(smi_info->si_sm,
                           resp, IPMI_MAX_MSG_LENGTH);
 
     if (resp_len < 4 ||
             resp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2 ||
             resp[1] != IPMI_GET_BMC_GLOBAL_ENABLES_CMD   ||
             resp[2] != 0) {
         pr_warn("Invalid return from get global enables command, cannot enable the event buffer\n");
         rv = -EINVAL;
         goto out;
     }
 
     if (resp[3] & IPMI_BMC_EVT_MSG_BUFF) {
         /* buffer is already enabled, nothing to do. */
         smi_info->supports_event_msg_buff = true;
         goto out;
     }
 
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
     msg[2] = resp[3] | IPMI_BMC_EVT_MSG_BUFF;
     smi_info->handlers->start_transaction(smi_info->si_sm, msg, 3);
 
     rv = wait_for_msg_done(smi_info);
     if (rv) {
         pr_warn("Error getting response from set global, enables command, the event buffer is not enabled\n");
         goto out;
     }
 
     resp_len = smi_info->handlers->get_result(smi_info->si_sm,
                           resp, IPMI_MAX_MSG_LENGTH);
 
     if (resp_len < 3 ||
             resp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2 ||
             resp[1] != IPMI_SET_BMC_GLOBAL_ENABLES_CMD) {
         pr_warn("Invalid return from get global, enables command, not enable the event buffer\n");
         rv = -EINVAL;
         goto out;
     }
 
     if (resp[2] != 0)
         /*
          * An error when setting the event buffer bit means
          * that the event buffer is not supported.
          */
         rv = -ENOENT;
     else
         smi_info->supports_event_msg_buff = true;
 
 out:
     kfree(resp);
     return rv;
 }
 
 #define IPMI_SI_ATTR(name) \
 static ssize_t name##_show(struct device *dev,          \
                struct device_attribute *attr,       \
                char *buf)                   \
 {                                   \
     struct smi_info *smi_info = dev_get_drvdata(dev);       \
                                     \
     return sysfs_emit(buf, "%u\n", smi_get_stat(smi_info, name));   \
 }                                   \
 static DEVICE_ATTR_RO(name)
 
 static ssize_t type_show(struct device *dev,
              struct device_attribute *attr,
              char *buf)
 {
     struct smi_info *smi_info = dev_get_drvdata(dev);
 
     return sysfs_emit(buf, "%s\n", si_to_str[smi_info->io.si_type]);
 }
 static DEVICE_ATTR_RO(type);
 
 static ssize_t interrupts_enabled_show(struct device *dev,
                        struct device_attribute *attr,
                        char *buf)
 {
     struct smi_info *smi_info = dev_get_drvdata(dev);
     int enabled = smi_info->io.irq && !smi_info->interrupt_disabled;
 
     return sysfs_emit(buf, "%d\n", enabled);
 }
 static DEVICE_ATTR_RO(interrupts_enabled);
 
 IPMI_SI_ATTR(short_timeouts);
 IPMI_SI_ATTR(long_timeouts);
 IPMI_SI_ATTR(idles);
 IPMI_SI_ATTR(interrupts);
 IPMI_SI_ATTR(attentions);
 IPMI_SI_ATTR(flag_fetches);
 IPMI_SI_ATTR(hosed_count);
 IPMI_SI_ATTR(complete_transactions);
 IPMI_SI_ATTR(events);
 IPMI_SI_ATTR(watchdog_pretimeouts);
 IPMI_SI_ATTR(incoming_messages);
 
 static ssize_t params_show(struct device *dev,
                struct device_attribute *attr,
                char *buf)
 {
     struct smi_info *smi_info = dev_get_drvdata(dev);
 
     return sysfs_emit(buf,
             "%s,%s,0x%lx,rsp=%d,rsi=%d,rsh=%d,irq=%d,ipmb=%d\n",
             si_to_str[smi_info->io.si_type],
             addr_space_to_str[smi_info->io.addr_space],
             smi_info->io.addr_data,
             smi_info->io.regspacing,
             smi_info->io.regsize,
             smi_info->io.regshift,
             smi_info->io.irq,
             smi_info->io.slave_addr);
 }
 static DEVICE_ATTR_RO(params);
 
 static struct attribute *ipmi_si_dev_attrs[] = {
     &dev_attr_type.attr,
     &dev_attr_interrupts_enabled.attr,
     &dev_attr_short_timeouts.attr,
     &dev_attr_long_timeouts.attr,
     &dev_attr_idles.attr,
     &dev_attr_interrupts.attr,
     &dev_attr_attentions.attr,
     &dev_attr_flag_fetches.attr,
     &dev_attr_hosed_count.attr,
     &dev_attr_complete_transactions.attr,
     &dev_attr_events.attr,
     &dev_attr_watchdog_pretimeouts.attr,
     &dev_attr_incoming_messages.attr,
     &dev_attr_params.attr,
     NULL
 };
 
 static const struct attribute_group ipmi_si_dev_attr_group = {
     .attrs      = ipmi_si_dev_attrs,
 };
 
 /*
  * oem_data_avail_to_receive_msg_avail
  * @info - smi_info structure with msg_flags set
  *
  * Converts flags from OEM_DATA_AVAIL to RECEIVE_MSG_AVAIL
  * Returns 1 indicating need to re-run handle_flags().
  */
 static int oem_data_avail_to_receive_msg_avail(struct smi_info *smi_info)
 {
     smi_info->msg_flags = ((smi_info->msg_flags & ~OEM_DATA_AVAIL) |
                    RECEIVE_MSG_AVAIL);
     return 1;
 }
 
 /*
  * setup_dell_poweredge_oem_data_handler
  * @info - smi_info.device_id must be populated
  *
  * Systems that match, but have firmware version < 1.40 may assert
  * OEM0_DATA_AVAIL on their own, without being told via Set Flags that
  * it's safe to do so.  Such systems will de-assert OEM1_DATA_AVAIL
  * upon receipt of IPMI_GET_MSG_CMD, so we should treat these flags
  * as RECEIVE_MSG_AVAIL instead.
  *
  * As Dell has no plans to release IPMI 1.5 firmware that *ever*
  * assert the OEM[012] bits, and if it did, the driver would have to
  * change to handle that properly, we don't actually check for the
  * firmware version.
  * Device ID = 0x20                BMC on PowerEdge 8G servers
  * Device Revision = 0x80
  * Firmware Revision1 = 0x01       BMC version 1.40
  * Firmware Revision2 = 0x40       BCD encoded
  * IPMI Version = 0x51             IPMI 1.5
  * Manufacturer ID = A2 02 00      Dell IANA
  *
  * Additionally, PowerEdge systems with IPMI < 1.5 may also assert
  * OEM0_DATA_AVAIL and needs to be treated as RECEIVE_MSG_AVAIL.
  *
  */
 #define DELL_POWEREDGE_8G_BMC_DEVICE_ID  0x20
 #define DELL_POWEREDGE_8G_BMC_DEVICE_REV 0x80
 #define DELL_POWEREDGE_8G_BMC_IPMI_VERSION 0x51
 #define DELL_IANA_MFR_ID 0x0002a2
 static void setup_dell_poweredge_oem_data_handler(struct smi_info *smi_info)
 {
     struct ipmi_device_id *id = &smi_info->device_id;
     if (id->manufacturer_id == DELL_IANA_MFR_ID) {
         if (id->device_id       == DELL_POWEREDGE_8G_BMC_DEVICE_ID  &&
             id->device_revision == DELL_POWEREDGE_8G_BMC_DEVICE_REV &&
             id->ipmi_version   == DELL_POWEREDGE_8G_BMC_IPMI_VERSION) {
             smi_info->oem_data_avail_handler =
                 oem_data_avail_to_receive_msg_avail;
         } else if (ipmi_version_major(id) < 1 ||
                (ipmi_version_major(id) == 1 &&
                 ipmi_version_minor(id) < 5)) {
             smi_info->oem_data_avail_handler =
                 oem_data_avail_to_receive_msg_avail;
         }
     }
 }
 
 #define CANNOT_RETURN_REQUESTED_LENGTH 0xCA
 static void return_hosed_msg_badsize(struct smi_info *smi_info)
 {
     struct ipmi_smi_msg *msg = smi_info->curr_msg;
 
     /* Make it a response */
     msg->rsp[0] = msg->data[0] | 4;
     msg->rsp[1] = msg->data[1];
     msg->rsp[2] = CANNOT_RETURN_REQUESTED_LENGTH;
     msg->rsp_size = 3;
     smi_info->curr_msg = NULL;
     deliver_recv_msg(smi_info, msg);
 }
 
 /*
  * dell_poweredge_bt_xaction_handler
  * @info - smi_info.device_id must be populated
  *
  * Dell PowerEdge servers with the BT interface (x6xx and 1750) will
  * not respond to a Get SDR command if the length of the data
  * requested is exactly 0x3A, which leads to command timeouts and no
  * data returned.  This intercepts such commands, and causes userspace
  * callers to try again with a different-sized buffer, which succeeds.
  */
 
 #define STORAGE_NETFN 0x0A
 #define STORAGE_CMD_GET_SDR 0x23
 static int dell_poweredge_bt_xaction_handler(struct notifier_block *self,
                          unsigned long unused,
                          void *in)
 {
     struct smi_info *smi_info = in;
     unsigned char *data = smi_info->curr_msg->data;
     unsigned int size   = smi_info->curr_msg->data_size;
     if (size >= 8 &&
         (data[0]>>2) == STORAGE_NETFN &&
         data[1] == STORAGE_CMD_GET_SDR &&
         data[7] == 0x3A) {
         return_hosed_msg_badsize(smi_info);
         return NOTIFY_STOP;
     }
     return NOTIFY_DONE;
 }
 
 static struct notifier_block dell_poweredge_bt_xaction_notifier = {
     .notifier_call  = dell_poweredge_bt_xaction_handler,
 };
 
 /*
  * setup_dell_poweredge_bt_xaction_handler
  * @info - smi_info.device_id must be filled in already
  *
  * Fills in smi_info.device_id.start_transaction_pre_hook
  * when we know what function to use there.
  */
 static void
 setup_dell_poweredge_bt_xaction_handler(struct smi_info *smi_info)
 {
     struct ipmi_device_id *id = &smi_info->device_id;
     if (id->manufacturer_id == DELL_IANA_MFR_ID &&
         smi_info->io.si_type == SI_BT)
         register_xaction_notifier(&dell_poweredge_bt_xaction_notifier);
 }
 
 /*
  * setup_oem_data_handler
  * @info - smi_info.device_id must be filled in already
  *
  * Fills in smi_info.device_id.oem_data_available_handler
  * when we know what function to use there.
  */
 
 static void setup_oem_data_handler(struct smi_info *smi_info)
 {
     setup_dell_poweredge_oem_data_handler(smi_info);
 }
 
 static void setup_xaction_handlers(struct smi_info *smi_info)
 {
     setup_dell_poweredge_bt_xaction_handler(smi_info);
 }
 
 static void check_for_broken_irqs(struct smi_info *smi_info)
 {
     check_clr_rcv_irq(smi_info);
     check_set_rcv_irq(smi_info);
 }
 
 static inline void stop_timer_and_thread(struct smi_info *smi_info)
 {
     if (smi_info->thread != NULL) {
         kthread_stop(smi_info->thread);
         smi_info->thread = NULL;
     }
 
     smi_info->timer_can_start = false;
     del_timer_sync(&smi_info->si_timer);
 }
 
 static struct smi_info *find_dup_si(struct smi_info *info)
 {
     struct smi_info *e;
 
     list_for_each_entry(e, &smi_infos, link) {
         if (e->io.addr_space != info->io.addr_space)
             continue;
         if (e->io.addr_data == info->io.addr_data) {
             /*
              * This is a cheap hack, ACPI doesn't have a defined
              * slave address but SMBIOS does.  Pick it up from
              * any source that has it available.
              */
             if (info->io.slave_addr && !e->io.slave_addr)
                 e->io.slave_addr = info->io.slave_addr;
             return e;
         }
     }
 
     return NULL;
 }
 
 int ipmi_si_add_smi(struct si_sm_io *io)
 {
     int rv = 0;
     struct smi_info *new_smi, *dup;
 
     /*
      * If the user gave us a hard-coded device at the same
      * address, they presumably want us to use it and not what is
      * in the firmware.
      */
     if (io->addr_source != SI_HARDCODED && io->addr_source != SI_HOTMOD &&
         ipmi_si_hardcode_match(io->addr_space, io->addr_data)) {
         dev_info(io->dev,
              "Hard-coded device at this address already exists");
         return -ENODEV;
     }
 
     if (!io->io_setup) {
         if (io->addr_space == IPMI_IO_ADDR_SPACE) {
             io->io_setup = ipmi_si_port_setup;
         } else if (io->addr_space == IPMI_MEM_ADDR_SPACE) {
             io->io_setup = ipmi_si_mem_setup;
         } else {
             return -EINVAL;
         }
     }
 
     new_smi = kzalloc(sizeof(*new_smi), GFP_KERNEL);
     if (!new_smi)
         return -ENOMEM;
     spin_lock_init(&new_smi->si_lock);
 
     new_smi->io = *io;
 
     mutex_lock(&smi_infos_lock);
     dup = find_dup_si(new_smi);
     if (dup) {
         if (new_smi->io.addr_source == SI_ACPI &&
             dup->io.addr_source == SI_SMBIOS) {
             /* We prefer ACPI over SMBIOS. */
             dev_info(dup->io.dev,
                  "Removing SMBIOS-specified %s state machine in favor of ACPI\n",
                  si_to_str[new_smi->io.si_type]);
             cleanup_one_si(dup);
         } else {
             dev_info(new_smi->io.dev,
                  "%s-specified %s state machine: duplicate\n",
                  ipmi_addr_src_to_str(new_smi->io.addr_source),
                  si_to_str[new_smi->io.si_type]);
             rv = -EBUSY;
             kfree(new_smi);
             goto out_err;
         }
     }
 
     pr_info("Adding %s-specified %s state machine\n",
         ipmi_addr_src_to_str(new_smi->io.addr_source),
         si_to_str[new_smi->io.si_type]);
 
     list_add_tail(&new_smi->link, &smi_infos);
 
     if (initialized)
         rv = try_smi_init(new_smi);
 out_err:
     mutex_unlock(&smi_infos_lock);
     return rv;
 }
 
 /*
  * Try to start up an interface.  Must be called with smi_infos_lock
  * held, primarily to keep smi_num consistent, we only one to do these
  * one at a time.
  */
 static int try_smi_init(struct smi_info *new_smi)
 {
     int rv = 0;
     int i;
 
     pr_info("Trying %s-specified %s state machine at %s address 0x%lx, slave address 0x%x, irq %d\n",
         ipmi_addr_src_to_str(new_smi->io.addr_source),
         si_to_str[new_smi->io.si_type],
         addr_space_to_str[new_smi->io.addr_space],
         new_smi->io.addr_data,
         new_smi->io.slave_addr, new_smi->io.irq);
 
     switch (new_smi->io.si_type) {
     case SI_KCS:
         new_smi->handlers = &kcs_smi_handlers;
         break;
 
     case SI_SMIC:
         new_smi->handlers = &smic_smi_handlers;
         break;
 
     case SI_BT:
         new_smi->handlers = &bt_smi_handlers;
         break;
 
     default:
         /* No support for anything else yet. */
         rv = -EIO;
         goto out_err;
     }
 
     new_smi->si_num = smi_num;
 
     /* Do this early so it's available for logs. */
     if (!new_smi->io.dev) {
         pr_err("IPMI interface added with no device\n");
         rv = -EIO;
         goto out_err;
     }
 
     /* Allocate the state machine's data and initialize it. */
     new_smi->si_sm = kmalloc(new_smi->handlers->size(), GFP_KERNEL);
     if (!new_smi->si_sm) {
         rv = -ENOMEM;
         goto out_err;
     }
     new_smi->io.io_size = new_smi->handlers->init_data(new_smi->si_sm,
                                &new_smi->io);
 
     /* Now that we know the I/O size, we can set up the I/O. */
     rv = new_smi->io.io_setup(&new_smi->io);
     if (rv) {
         dev_err(new_smi->io.dev, "Could not set up I/O space\n");
         goto out_err;
     }
 
     /* Do low-level detection first. */
     if (new_smi->handlers->detect(new_smi->si_sm)) {
         if (new_smi->io.addr_source)
             dev_err(new_smi->io.dev,
                 "Interface detection failed\n");
         rv = -ENODEV;
         goto out_err;
     }
 
     /*
      * Attempt a get device id command.  If it fails, we probably
      * don't have a BMC here.
      */
     rv = try_get_dev_id(new_smi);
     if (rv) {
         if (new_smi->io.addr_source)
             dev_err(new_smi->io.dev,
                    "There appears to be no BMC at this location\n");
         goto out_err;
     }
 
     setup_oem_data_handler(new_smi);
     setup_xaction_handlers(new_smi);
     check_for_broken_irqs(new_smi);
 
     new_smi->waiting_msg = NULL;
     new_smi->curr_msg = NULL;
     atomic_set(&new_smi->req_events, 0);
     new_smi->run_to_completion = false;
     for (i = 0; i < SI_NUM_STATS; i++)
         atomic_set(&new_smi->stats[i], 0);
 
     new_smi->interrupt_disabled = true;
     atomic_set(&new_smi->need_watch, 0);
 
     rv = try_enable_event_buffer(new_smi);
     if (rv == 0)
         new_smi->has_event_buffer = true;
 
     /*
      * Start clearing the flags before we enable interrupts or the
      * timer to avoid racing with the timer.
      */
     start_clear_flags(new_smi);
 
     /*
      * IRQ is defined to be set when non-zero.  req_events will
      * cause a global flags check that will enable interrupts.
      */
     if (new_smi->io.irq) {
         new_smi->interrupt_disabled = false;
         atomic_set(&new_smi->req_events, 1);
     }
 
     dev_set_drvdata(new_smi->io.dev, new_smi);
     rv = device_add_group(new_smi->io.dev, &ipmi_si_dev_attr_group);
     if (rv) {
         dev_err(new_smi->io.dev,
             "Unable to add device attributes: error %d\n",
             rv);
         goto out_err;
     }
     new_smi->dev_group_added = true;
 
     rv = ipmi_register_smi(&handlers,
                    new_smi,
                    new_smi->io.dev,
                    new_smi->io.slave_addr);
     if (rv) {
         dev_err(new_smi->io.dev,
             "Unable to register device: error %d\n",
             rv);
         goto out_err;
     }
 
     /* Don't increment till we know we have succeeded. */
     smi_num++;
 
     dev_info(new_smi->io.dev, "IPMI %s interface initialized\n",
          si_to_str[new_smi->io.si_type]);
 
     WARN_ON(new_smi->io.dev->init_name != NULL);
 
  out_err:
     if (rv && new_smi->io.io_cleanup) {
         new_smi->io.io_cleanup(&new_smi->io);
         new_smi->io.io_cleanup = NULL;
     }
 
     return rv;
 }
 
 static int __init init_ipmi_si(void)
 {
     struct smi_info *e;
     enum ipmi_addr_src type = SI_INVALID;
 
     if (initialized)
         return 0;
 
     ipmi_hardcode_init();
 
     pr_info("IPMI System Interface driver\n");
 
     ipmi_si_platform_init();
 
     ipmi_si_pci_init();
 
     ipmi_si_parisc_init();
 
     /* We prefer devices with interrupts, but in the case of a machine
        with multiple BMCs we assume that there will be several instances
        of a given type so if we succeed in registering a type then also
        try to register everything else of the same type */
     mutex_lock(&smi_infos_lock);
     list_for_each_entry(e, &smi_infos, link) {
         /* Try to register a device if it has an IRQ and we either
            haven't successfully registered a device yet or this
            device has the same type as one we successfully registered */
         if (e->io.irq && (!type || e->io.addr_source == type)) {
             if (!try_smi_init(e)) {
                 type = e->io.addr_source;
             }
         }
     }
 
     /* type will only have been set if we successfully registered an si */
     if (type)
         goto skip_fallback_noirq;
 
     /* Fall back to the preferred device */
 
     list_for_each_entry(e, &smi_infos, link) {
         if (!e->io.irq && (!type || e->io.addr_source == type)) {
             if (!try_smi_init(e)) {
                 type = e->io.addr_source;
             }
         }
     }
 
 skip_fallback_noirq:
     initialized = true;
     mutex_unlock(&smi_infos_lock);
 
     if (type)
         return 0;
 
     mutex_lock(&smi_infos_lock);
     if (unload_when_empty && list_empty(&smi_infos)) {
         mutex_unlock(&smi_infos_lock);
         cleanup_ipmi_si();
         pr_warn("Unable to find any System Interface(s)\n");
         return -ENODEV;
     } else {
         mutex_unlock(&smi_infos_lock);
         return 0;
     }
 }
 module_init(init_ipmi_si);
 
 static void shutdown_smi(void *send_info)
 {
     struct smi_info *smi_info = send_info;
 
     if (smi_info->dev_group_added) {
         device_remove_group(smi_info->io.dev, &ipmi_si_dev_attr_group);
         smi_info->dev_group_added = false;
     }
     if (smi_info->io.dev)
         dev_set_drvdata(smi_info->io.dev, NULL);
 
     /*
      * Make sure that interrupts, the timer and the thread are
      * stopped and will not run again.
      */
     smi_info->interrupt_disabled = true;
     if (smi_info->io.irq_cleanup) {
         smi_info->io.irq_cleanup(&smi_info->io);
         smi_info->io.irq_cleanup = NULL;
     }
     stop_timer_and_thread(smi_info);
 
     /*
      * Wait until we know that we are out of any interrupt
      * handlers might have been running before we freed the
      * interrupt.
      */
     synchronize_rcu();
 
     /*
      * Timeouts are stopped, now make sure the interrupts are off
      * in the BMC.  Note that timers and CPU interrupts are off,
      * so no need for locks.
      */
     while (smi_info->curr_msg || (smi_info->si_state != SI_NORMAL)) {
         poll(smi_info);
         schedule_timeout_uninterruptible(1);
     }
     if (smi_info->handlers)
         disable_si_irq(smi_info);
     while (smi_info->curr_msg || (smi_info->si_state != SI_NORMAL)) {
         poll(smi_info);
         schedule_timeout_uninterruptible(1);
     }
     if (smi_info->handlers)
         smi_info->handlers->cleanup(smi_info->si_sm);
 
     if (smi_info->io.io_cleanup) {
         smi_info->io.io_cleanup(&smi_info->io);
         smi_info->io.io_cleanup = NULL;
     }
 
     kfree(smi_info->si_sm);
     smi_info->si_sm = NULL;
 
     smi_info->intf = NULL;
 }
 
 /*
  * Must be called with smi_infos_lock held, to serialize the
  * smi_info->intf check.
  */
 static void cleanup_one_si(struct smi_info *smi_info)
 {
     if (!smi_info)
         return;
 
     list_del(&smi_info->link);
     ipmi_unregister_smi(smi_info->intf);
     kfree(smi_info);
 }
 
 void ipmi_si_remove_by_dev(struct device *dev)
 {
     struct smi_info *e;
 
     mutex_lock(&smi_infos_lock);
     list_for_each_entry(e, &smi_infos, link) {
         if (e->io.dev == dev) {
             cleanup_one_si(e);
             break;
         }
     }
     mutex_unlock(&smi_infos_lock);
 }
 
 struct device *ipmi_si_remove_by_data(int addr_space, enum si_type si_type,
                       unsigned long addr)
 {
     /* remove */
     struct smi_info *e, *tmp_e;
     struct device *dev = NULL;
 
     mutex_lock(&smi_infos_lock);
     list_for_each_entry_safe(e, tmp_e, &smi_infos, link) {
         if (e->io.addr_space != addr_space)
             continue;
         if (e->io.si_type != si_type)
             continue;
         if (e->io.addr_data == addr) {
             dev = get_device(e->io.dev);
             cleanup_one_si(e);
         }
     }
     mutex_unlock(&smi_infos_lock);
 
     return dev;
 }
 
 static void cleanup_ipmi_si(void)
 {
     struct smi_info *e, *tmp_e;
 
     if (!initialized)
         return;
 
     ipmi_si_pci_shutdown();
 
     ipmi_si_parisc_shutdown();
 
     ipmi_si_platform_shutdown();
 
     mutex_lock(&smi_infos_lock);
     list_for_each_entry_safe(e, tmp_e, &smi_infos, link)
         cleanup_one_si(e);
     mutex_unlock(&smi_infos_lock);
 
     ipmi_si_hardcode_exit();
     ipmi_si_hotmod_exit();
 }
 module_exit(cleanup_ipmi_si);
 
 MODULE_ALIAS("platform:dmi-ipmi-si");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Corey Minyard <minyard@mvista.com>");
 MODULE_DESCRIPTION("Interface to the IPMI driver for the KCS, SMIC, and BT system interfaces.");

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