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	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_ssif.c
  *
  * The interface to the IPMI driver for SMBus access to a SMBus
  * compliant device.  Called SSIF by the IPMI spec.
  *
  * Author: Intel Corporation
  *         Todd Davis <todd.c.davis@intel.com>
  *
  * Rewritten by Corey Minyard <minyard@acm.org> to support the
  * non-blocking I2C interface, add support for multi-part
  * transactions, add PEC support, and general clenaup.
  *
  * Copyright 2003 Intel Corporation
  * Copyright 2005 MontaVista Software
  */
 
 /*
  * This file holds the "policy" for the interface to the SSIF state
  * machine.  It does the configuration, handles timers and interrupts,
  * and drives the real SSIF state machine.
  */
 
 #define pr_fmt(fmt) "ipmi_ssif: " fmt
 #define dev_fmt(fmt) "ipmi_ssif: " fmt
 
 #if defined(MODVERSIONS)
 #include <linux/modversions.h>
 #endif
 
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/timer.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>
 #include <linux/list.h>
 #include <linux/i2c.h>
 #include <linux/ipmi_smi.h>
 #include <linux/init.h>
 #include <linux/dmi.h>
 #include <linux/kthread.h>
 #include <linux/acpi.h>
 #include <linux/ctype.h>
 #include <linux/time64.h>
 #include "ipmi_dmi.h"
 
 #define DEVICE_NAME "ipmi_ssif"
 
 #define IPMI_GET_SYSTEM_INTERFACE_CAPABILITIES_CMD  0x57
 
 #define SSIF_IPMI_REQUEST           2
 #define SSIF_IPMI_MULTI_PART_REQUEST_START  6
 #define SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE 7
 #define SSIF_IPMI_MULTI_PART_REQUEST_END    8
 #define SSIF_IPMI_RESPONSE          3
 #define SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE    9
 
 /* ssif_debug is a bit-field
  *  SSIF_DEBUG_MSG -    commands and their responses
  *  SSIF_DEBUG_STATES - message states
  *  SSIF_DEBUG_TIMING -  Measure times between events in the driver
  */
 #define SSIF_DEBUG_TIMING   4
 #define SSIF_DEBUG_STATE    2
 #define SSIF_DEBUG_MSG      1
 #define SSIF_NODEBUG        0
 #define SSIF_DEFAULT_DEBUG  (SSIF_NODEBUG)
 
 /*
  * Timer values
  */
 #define SSIF_MSG_USEC       20000   /* 20ms between message tries. */
 #define SSIF_MSG_PART_USEC  5000    /* 5ms for a message part */
 
 /* How many times to we retry sending/receiving the message. */
 #define SSIF_SEND_RETRIES   5
 #define SSIF_RECV_RETRIES   250
 
 #define SSIF_MSG_MSEC       (SSIF_MSG_USEC / 1000)
 #define SSIF_MSG_JIFFIES    ((SSIF_MSG_USEC * 1000) / TICK_NSEC)
 #define SSIF_MSG_PART_JIFFIES   ((SSIF_MSG_PART_USEC * 1000) / TICK_NSEC)
 
 /*
  * Timeout for the watch, only used for get flag timer.
  */
 #define SSIF_WATCH_MSG_TIMEOUT      msecs_to_jiffies(10)
 #define SSIF_WATCH_WATCHDOG_TIMEOUT msecs_to_jiffies(250)
 
 enum ssif_intf_state {
     SSIF_NORMAL,
     SSIF_GETTING_FLAGS,
     SSIF_GETTING_EVENTS,
     SSIF_CLEARING_FLAGS,
     SSIF_GETTING_MESSAGES,
     /* FIXME - add watchdog stuff. */
 };
 
 #define SSIF_IDLE(ssif)  ((ssif)->ssif_state == SSIF_NORMAL \
               && (ssif)->curr_msg == NULL)
 
 /*
  * Indexes into stats[] in ssif_info below.
  */
 enum ssif_stat_indexes {
     /* Number of total messages sent. */
     SSIF_STAT_sent_messages = 0,
 
     /*
      * Number of message parts sent.  Messages may be broken into
      * parts if they are long.
      */
     SSIF_STAT_sent_messages_parts,
 
     /*
      * Number of time a message was retried.
      */
     SSIF_STAT_send_retries,
 
     /*
      * Number of times the send of a message failed.
      */
     SSIF_STAT_send_errors,
 
     /*
      * Number of message responses received.
      */
     SSIF_STAT_received_messages,
 
     /*
      * Number of message fragments received.
      */
     SSIF_STAT_received_message_parts,
 
     /*
      * Number of times the receive of a message was retried.
      */
     SSIF_STAT_receive_retries,
 
     /*
      * Number of errors receiving messages.
      */
     SSIF_STAT_receive_errors,
 
     /*
      * Number of times a flag fetch was requested.
      */
     SSIF_STAT_flag_fetches,
 
     /*
      * Number of times the hardware didn't follow the state machine.
      */
     SSIF_STAT_hosed,
 
     /*
      * Number of received events.
      */
     SSIF_STAT_events,
 
     /* Number of asyncronous messages received. */
     SSIF_STAT_incoming_messages,
 
     /* Number of watchdog pretimeouts. */
     SSIF_STAT_watchdog_pretimeouts,
 
     /* Number of alers received. */
     SSIF_STAT_alerts,
 
     /* Always add statistics before this value, it must be last. */
     SSIF_NUM_STATS
 };
 
 struct ssif_addr_info {
     struct i2c_board_info binfo;
     char *adapter_name;
     int debug;
     int slave_addr;
     enum ipmi_addr_src addr_src;
     union ipmi_smi_info_union addr_info;
     struct device *dev;
     struct i2c_client *client;
 
     struct mutex clients_mutex;
     struct list_head clients;
 
     struct list_head link;
 };
 
 struct ssif_info;
 
 typedef void (*ssif_i2c_done)(struct ssif_info *ssif_info, int result,
                  unsigned char *data, unsigned int len);
 
 struct ssif_info {
     struct ipmi_smi     *intf;
     spinlock_t      lock;
     struct ipmi_smi_msg *waiting_msg;
     struct ipmi_smi_msg *curr_msg;
     enum ssif_intf_state ssif_state;
     unsigned long       ssif_debug;
 
     struct ipmi_smi_handlers handlers;
 
     enum ipmi_addr_src addr_source; /* ACPI, PCI, SMBIOS, hardcode, etc. */
     union ipmi_smi_info_union addr_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
     unsigned char       msg_flags;
 
     u8          global_enables;
     bool            has_event_buffer;
     bool            supports_alert;
 
     /*
      * Used to tell what we should do with alerts.  If we are
      * waiting on a response, read the data immediately.
      */
     bool            got_alert;
     bool            waiting_alert;
 
     /*
      * If set to true, this will request events the next time the
      * state machine is idle.
      */
     bool                req_events;
 
     /*
      * If set to true, this will request flags the next time the
      * state machine is idle.
      */
     bool                req_flags;
 
     /*
      * Used to perform timer operations when run-to-completion
      * mode is on.  This is a countdown timer.
      */
     int                 rtc_us_timer;
 
     /* Used for sending/receiving data.  +1 for the length. */
     unsigned char data[IPMI_MAX_MSG_LENGTH + 1];
     unsigned int  data_len;
 
     /* Temp receive buffer, gets copied into data. */
     unsigned char recv[I2C_SMBUS_BLOCK_MAX];
 
     struct i2c_client *client;
     ssif_i2c_done done_handler;
 
     /* Thread interface handling */
     struct task_struct *thread;
     struct completion wake_thread;
     bool stopping;
     int i2c_read_write;
     int i2c_command;
     unsigned char *i2c_data;
     unsigned int i2c_size;
 
     struct timer_list retry_timer;
     int retries_left;
 
     long watch_timeout;     /* Timeout for flags check, 0 if off. */
     struct timer_list watch_timer;  /* Flag fetch timer. */
 
     /* Info from SSIF cmd */
     unsigned char max_xmit_msg_size;
     unsigned char max_recv_msg_size;
     bool cmd8_works; /* See test_multipart_messages() for details. */
     unsigned int  multi_support;
     int           supports_pec;
 
 #define SSIF_NO_MULTI       0
 #define SSIF_MULTI_2_PART   1
 #define SSIF_MULTI_n_PART   2
     unsigned char *multi_data;
     unsigned int  multi_len;
     unsigned int  multi_pos;
 
     atomic_t stats[SSIF_NUM_STATS];
 };
 
 #define ssif_inc_stat(ssif, stat) \
     atomic_inc(&(ssif)->stats[SSIF_STAT_ ## stat])
 #define ssif_get_stat(ssif, stat) \
     ((unsigned int) atomic_read(&(ssif)->stats[SSIF_STAT_ ## stat]))
 
 static bool initialized;
 static bool platform_registered;
 
 static void return_hosed_msg(struct ssif_info *ssif_info,
                  struct ipmi_smi_msg *msg);
 static void start_next_msg(struct ssif_info *ssif_info, unsigned long *flags);
 static int start_send(struct ssif_info *ssif_info,
               unsigned char   *data,
               unsigned int    len);
 
 static unsigned long *ipmi_ssif_lock_cond(struct ssif_info *ssif_info,
                       unsigned long *flags)
     __acquires(&ssif_info->lock)
 {
     spin_lock_irqsave(&ssif_info->lock, *flags);
     return flags;
 }
 
 static void ipmi_ssif_unlock_cond(struct ssif_info *ssif_info,
                   unsigned long *flags)
     __releases(&ssif_info->lock)
 {
     spin_unlock_irqrestore(&ssif_info->lock, *flags);
 }
 
 static void deliver_recv_msg(struct ssif_info *ssif_info,
                  struct ipmi_smi_msg *msg)
 {
     if (msg->rsp_size < 0) {
         return_hosed_msg(ssif_info, msg);
         dev_err(&ssif_info->client->dev,
             "%s: Malformed message: rsp_size = %d\n",
                __func__, msg->rsp_size);
     } else {
         ipmi_smi_msg_received(ssif_info->intf, msg);
     }
 }
 
 static void return_hosed_msg(struct ssif_info *ssif_info,
                  struct ipmi_smi_msg *msg)
 {
     ssif_inc_stat(ssif_info, hosed);
 
     /* Make it a response */
     msg->rsp[0] = msg->data[0] | 4;
     msg->rsp[1] = msg->data[1];
     msg->rsp[2] = 0xFF; /* Unknown error. */
     msg->rsp_size = 3;
 
     deliver_recv_msg(ssif_info, msg);
 }
 
 /*
  * Must be called with the message lock held.  This will release the
  * message lock.  Note that the caller will check SSIF_IDLE and start a
  * new operation, so there is no need to check for new messages to
  * start in here.
  */
 static void start_clear_flags(struct ssif_info *ssif_info, unsigned long *flags)
 {
     unsigned char msg[3];
 
     ssif_info->msg_flags &= ~WDT_PRE_TIMEOUT_INT;
     ssif_info->ssif_state = SSIF_CLEARING_FLAGS;
     ipmi_ssif_unlock_cond(ssif_info, flags);
 
     /* 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;
 
     if (start_send(ssif_info, msg, 3) != 0) {
         /* Error, just go to normal state. */
         ssif_info->ssif_state = SSIF_NORMAL;
     }
 }
 
 static void start_flag_fetch(struct ssif_info *ssif_info, unsigned long *flags)
 {
     unsigned char mb[2];
 
     ssif_info->req_flags = false;
     ssif_info->ssif_state = SSIF_GETTING_FLAGS;
     ipmi_ssif_unlock_cond(ssif_info, flags);
 
     mb[0] = (IPMI_NETFN_APP_REQUEST << 2);
     mb[1] = IPMI_GET_MSG_FLAGS_CMD;
     if (start_send(ssif_info, mb, 2) != 0)
         ssif_info->ssif_state = SSIF_NORMAL;
 }
 
 static void check_start_send(struct ssif_info *ssif_info, unsigned long *flags,
                  struct ipmi_smi_msg *msg)
 {
     if (start_send(ssif_info, msg->data, msg->data_size) != 0) {
         unsigned long oflags;
 
         flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
         ssif_info->curr_msg = NULL;
         ssif_info->ssif_state = SSIF_NORMAL;
         ipmi_ssif_unlock_cond(ssif_info, flags);
         ipmi_free_smi_msg(msg);
     }
 }
 
 static void start_event_fetch(struct ssif_info *ssif_info, unsigned long *flags)
 {
     struct ipmi_smi_msg *msg;
 
     ssif_info->req_events = false;
 
     msg = ipmi_alloc_smi_msg();
     if (!msg) {
         ssif_info->ssif_state = SSIF_NORMAL;
         ipmi_ssif_unlock_cond(ssif_info, flags);
         return;
     }
 
     ssif_info->curr_msg = msg;
     ssif_info->ssif_state = SSIF_GETTING_EVENTS;
     ipmi_ssif_unlock_cond(ssif_info, flags);
 
     msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
     msg->data[1] = IPMI_READ_EVENT_MSG_BUFFER_CMD;
     msg->data_size = 2;
 
     check_start_send(ssif_info, flags, msg);
 }
 
 static void start_recv_msg_fetch(struct ssif_info *ssif_info,
                  unsigned long *flags)
 {
     struct ipmi_smi_msg *msg;
 
     msg = ipmi_alloc_smi_msg();
     if (!msg) {
         ssif_info->ssif_state = SSIF_NORMAL;
         ipmi_ssif_unlock_cond(ssif_info, flags);
         return;
     }
 
     ssif_info->curr_msg = msg;
     ssif_info->ssif_state = SSIF_GETTING_MESSAGES;
     ipmi_ssif_unlock_cond(ssif_info, flags);
 
     msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
     msg->data[1] = IPMI_GET_MSG_CMD;
     msg->data_size = 2;
 
     check_start_send(ssif_info, flags, msg);
 }
 
 /*
  * Must be called with the message lock held.  This will release the
  * message lock.  Note that the caller will check SSIF_IDLE and start a
  * new operation, so there is no need to check for new messages to
  * start in here.
  */
 static void handle_flags(struct ssif_info *ssif_info, unsigned long *flags)
 {
     if (ssif_info->msg_flags & WDT_PRE_TIMEOUT_INT) {
         /* Watchdog pre-timeout */
         ssif_inc_stat(ssif_info, watchdog_pretimeouts);
         start_clear_flags(ssif_info, flags);
         ipmi_smi_watchdog_pretimeout(ssif_info->intf);
     } else if (ssif_info->msg_flags & RECEIVE_MSG_AVAIL)
         /* Messages available. */
         start_recv_msg_fetch(ssif_info, flags);
     else if (ssif_info->msg_flags & EVENT_MSG_BUFFER_FULL)
         /* Events available. */
         start_event_fetch(ssif_info, flags);
     else {
         ssif_info->ssif_state = SSIF_NORMAL;
         ipmi_ssif_unlock_cond(ssif_info, flags);
     }
 }
 
 static int ipmi_ssif_thread(void *data)
 {
     struct ssif_info *ssif_info = data;
 
     while (!kthread_should_stop()) {
         int result;
 
         /* Wait for something to do */
         result = wait_for_completion_interruptible(
                         &ssif_info->wake_thread);
         if (ssif_info->stopping)
             break;
         if (result == -ERESTARTSYS)
             continue;
         init_completion(&ssif_info->wake_thread);
 
         if (ssif_info->i2c_read_write == I2C_SMBUS_WRITE) {
             result = i2c_smbus_write_block_data(
                 ssif_info->client, ssif_info->i2c_command,
                 ssif_info->i2c_data[0],
                 ssif_info->i2c_data + 1);
             ssif_info->done_handler(ssif_info, result, NULL, 0);
         } else {
             result = i2c_smbus_read_block_data(
                 ssif_info->client, ssif_info->i2c_command,
                 ssif_info->i2c_data);
             if (result < 0)
                 ssif_info->done_handler(ssif_info, result,
                             NULL, 0);
             else
                 ssif_info->done_handler(ssif_info, 0,
                             ssif_info->i2c_data,
                             result);
         }
     }
 
     return 0;
 }
 
 static void ssif_i2c_send(struct ssif_info *ssif_info,
             ssif_i2c_done handler,
             int read_write, int command,
             unsigned char *data, unsigned int size)
 {
     ssif_info->done_handler = handler;
 
     ssif_info->i2c_read_write = read_write;
     ssif_info->i2c_command = command;
     ssif_info->i2c_data = data;
     ssif_info->i2c_size = size;
     complete(&ssif_info->wake_thread);
 }
 
 
 static void msg_done_handler(struct ssif_info *ssif_info, int result,
                  unsigned char *data, unsigned int len);
 
 static void start_get(struct ssif_info *ssif_info)
 {
     ssif_info->rtc_us_timer = 0;
     ssif_info->multi_pos = 0;
 
     ssif_i2c_send(ssif_info, msg_done_handler, I2C_SMBUS_READ,
           SSIF_IPMI_RESPONSE,
           ssif_info->recv, I2C_SMBUS_BLOCK_DATA);
 }
 
 static void retry_timeout(struct timer_list *t)
 {
     struct ssif_info *ssif_info = from_timer(ssif_info, t, retry_timer);
     unsigned long oflags, *flags;
     bool waiting;
 
     if (ssif_info->stopping)
         return;
 
     flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
     waiting = ssif_info->waiting_alert;
     ssif_info->waiting_alert = false;
     ipmi_ssif_unlock_cond(ssif_info, flags);
 
     if (waiting)
         start_get(ssif_info);
 }
 
 static void watch_timeout(struct timer_list *t)
 {
     struct ssif_info *ssif_info = from_timer(ssif_info, t, watch_timer);
     unsigned long oflags, *flags;
 
     if (ssif_info->stopping)
         return;
 
     flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
     if (ssif_info->watch_timeout) {
         mod_timer(&ssif_info->watch_timer,
               jiffies + ssif_info->watch_timeout);
         if (SSIF_IDLE(ssif_info)) {
             start_flag_fetch(ssif_info, flags); /* Releases lock */
             return;
         }
         ssif_info->req_flags = true;
     }
     ipmi_ssif_unlock_cond(ssif_info, flags);
 }
 
 static void ssif_alert(struct i2c_client *client, enum i2c_alert_protocol type,
                unsigned int data)
 {
     struct ssif_info *ssif_info = i2c_get_clientdata(client);
     unsigned long oflags, *flags;
     bool do_get = false;
 
     if (type != I2C_PROTOCOL_SMBUS_ALERT)
         return;
 
     ssif_inc_stat(ssif_info, alerts);
 
     flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
     if (ssif_info->waiting_alert) {
         ssif_info->waiting_alert = false;
         del_timer(&ssif_info->retry_timer);
         do_get = true;
     } else if (ssif_info->curr_msg) {
         ssif_info->got_alert = true;
     }
     ipmi_ssif_unlock_cond(ssif_info, flags);
     if (do_get)
         start_get(ssif_info);
 }
 
 static int start_resend(struct ssif_info *ssif_info);
 
 static void msg_done_handler(struct ssif_info *ssif_info, int result,
                  unsigned char *data, unsigned int len)
 {
     struct ipmi_smi_msg *msg;
     unsigned long oflags, *flags;
 
     /*
      * We are single-threaded here, so no need for a lock until we
      * start messing with driver states or the queues.
      */
 
     if (result < 0) {
         ssif_info->retries_left--;
         if (ssif_info->retries_left > 0) {
             ssif_inc_stat(ssif_info, receive_retries);
 
             flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
             ssif_info->waiting_alert = true;
             ssif_info->rtc_us_timer = SSIF_MSG_USEC;
             if (!ssif_info->stopping)
                 mod_timer(&ssif_info->retry_timer,
                       jiffies + SSIF_MSG_JIFFIES);
             ipmi_ssif_unlock_cond(ssif_info, flags);
             return;
         }
 
         ssif_inc_stat(ssif_info, receive_errors);
 
         if  (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
             dev_dbg(&ssif_info->client->dev,
                 "%s: Error %d\n", __func__, result);
         len = 0;
         goto continue_op;
     }
 
     if ((len > 1) && (ssif_info->multi_pos == 0)
                 && (data[0] == 0x00) && (data[1] == 0x01)) {
         /* Start of multi-part read.  Start the next transaction. */
         int i;
 
         ssif_inc_stat(ssif_info, received_message_parts);
 
         /* Remove the multi-part read marker. */
         len -= 2;
         data += 2;
         for (i = 0; i < len; i++)
             ssif_info->data[i] = data[i];
         ssif_info->multi_len = len;
         ssif_info->multi_pos = 1;
 
         ssif_i2c_send(ssif_info, msg_done_handler, I2C_SMBUS_READ,
              SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE,
              ssif_info->recv, I2C_SMBUS_BLOCK_DATA);
         return;
     } else if (ssif_info->multi_pos) {
         /* Middle of multi-part read.  Start the next transaction. */
         int i;
         unsigned char blocknum;
 
         if (len == 0) {
             result = -EIO;
             if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
                 dev_dbg(&ssif_info->client->dev,
                     "Middle message with no data\n");
 
             goto continue_op;
         }
 
         blocknum = data[0];
         len--;
         data++;
 
         if (blocknum != 0xff && len != 31) {
             /* All blocks but the last must have 31 data bytes. */
             result = -EIO;
             if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
                 dev_dbg(&ssif_info->client->dev,
                     "Received middle message <31\n");
 
             goto continue_op;
         }
 
         if (ssif_info->multi_len + len > IPMI_MAX_MSG_LENGTH) {
             /* Received message too big, abort the operation. */
             result = -E2BIG;
             if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
                 dev_dbg(&ssif_info->client->dev,
                     "Received message too big\n");
 
             goto continue_op;
         }
 
         for (i = 0; i < len; i++)
             ssif_info->data[i + ssif_info->multi_len] = data[i];
         ssif_info->multi_len += len;
         if (blocknum == 0xff) {
             /* End of read */
             len = ssif_info->multi_len;
             data = ssif_info->data;
         } else if (blocknum + 1 != ssif_info->multi_pos) {
             /*
              * Out of sequence block, just abort.  Block
              * numbers start at zero for the second block,
              * but multi_pos starts at one, so the +1.
              */
             if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
                 dev_dbg(&ssif_info->client->dev,
                     "Received message out of sequence, expected %u, got %u\n",
                     ssif_info->multi_pos - 1, blocknum);
             result = -EIO;
         } else {
             ssif_inc_stat(ssif_info, received_message_parts);
 
             ssif_info->multi_pos++;
 
             ssif_i2c_send(ssif_info, msg_done_handler,
                   I2C_SMBUS_READ,
                   SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE,
                   ssif_info->recv,
                   I2C_SMBUS_BLOCK_DATA);
             return;
         }
     }
 
  continue_op:
     if (result < 0) {
         ssif_inc_stat(ssif_info, receive_errors);
     } else {
         ssif_inc_stat(ssif_info, received_messages);
         ssif_inc_stat(ssif_info, received_message_parts);
     }
 
     if (ssif_info->ssif_debug & SSIF_DEBUG_STATE)
         dev_dbg(&ssif_info->client->dev,
             "DONE 1: state = %d, result=%d\n",
             ssif_info->ssif_state, result);
 
     flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
     msg = ssif_info->curr_msg;
     if (msg) {
         if (data) {
             if (len > IPMI_MAX_MSG_LENGTH)
                 len = IPMI_MAX_MSG_LENGTH;
             memcpy(msg->rsp, data, len);
         } else {
             len = 0;
         }
         msg->rsp_size = len;
         ssif_info->curr_msg = NULL;
     }
 
     switch (ssif_info->ssif_state) {
     case SSIF_NORMAL:
         ipmi_ssif_unlock_cond(ssif_info, flags);
         if (!msg)
             break;
 
         if (result < 0)
             return_hosed_msg(ssif_info, msg);
         else
             deliver_recv_msg(ssif_info, msg);
         break;
 
     case SSIF_GETTING_FLAGS:
         /* We got the flags from the SSIF, now handle them. */
         if ((result < 0) || (len < 4) || (data[2] != 0)) {
             /*
              * Error fetching flags, or invalid length,
              * just give up for now.
              */
             ssif_info->ssif_state = SSIF_NORMAL;
             ipmi_ssif_unlock_cond(ssif_info, flags);
             dev_warn(&ssif_info->client->dev,
                  "Error getting flags: %d %d, %x\n",
                  result, len, (len >= 3) ? data[2] : 0);
         } else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
                || data[1] != IPMI_GET_MSG_FLAGS_CMD) {
             /*
              * Don't abort here, maybe it was a queued
              * response to a previous command.
              */
             ipmi_ssif_unlock_cond(ssif_info, flags);
             dev_warn(&ssif_info->client->dev,
                  "Invalid response getting flags: %x %x\n",
                  data[0], data[1]);
         } else {
             ssif_inc_stat(ssif_info, flag_fetches);
             ssif_info->msg_flags = data[3];
             handle_flags(ssif_info, flags);
         }
         break;
 
     case SSIF_CLEARING_FLAGS:
         /* We cleared the flags. */
         if ((result < 0) || (len < 3) || (data[2] != 0)) {
             /* Error clearing flags */
             dev_warn(&ssif_info->client->dev,
                  "Error clearing flags: %d %d, %x\n",
                  result, len, (len >= 3) ? data[2] : 0);
         } else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
                || data[1] != IPMI_CLEAR_MSG_FLAGS_CMD) {
             dev_warn(&ssif_info->client->dev,
                  "Invalid response clearing flags: %x %x\n",
                  data[0], data[1]);
         }
         ssif_info->ssif_state = SSIF_NORMAL;
         ipmi_ssif_unlock_cond(ssif_info, flags);
         break;
 
     case SSIF_GETTING_EVENTS:
         if (!msg) {
             /* Should never happen, but just in case. */
             dev_warn(&ssif_info->client->dev,
                  "No message set while getting events\n");
             ipmi_ssif_unlock_cond(ssif_info, flags);
             break;
         }
 
         if ((result < 0) || (len < 3) || (msg->rsp[2] != 0)) {
             /* Error getting event, probably done. */
             msg->done(msg);
 
             /* Take off the event flag. */
             ssif_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
             handle_flags(ssif_info, flags);
         } else if (msg->rsp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
                || msg->rsp[1] != IPMI_READ_EVENT_MSG_BUFFER_CMD) {
             dev_warn(&ssif_info->client->dev,
                  "Invalid response getting events: %x %x\n",
                  msg->rsp[0], msg->rsp[1]);
             msg->done(msg);
             /* Take off the event flag. */
             ssif_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
             handle_flags(ssif_info, flags);
         } else {
             handle_flags(ssif_info, flags);
             ssif_inc_stat(ssif_info, events);
             deliver_recv_msg(ssif_info, msg);
         }
         break;
 
     case SSIF_GETTING_MESSAGES:
         if (!msg) {
             /* Should never happen, but just in case. */
             dev_warn(&ssif_info->client->dev,
                  "No message set while getting messages\n");
             ipmi_ssif_unlock_cond(ssif_info, flags);
             break;
         }
 
         if ((result < 0) || (len < 3) || (msg->rsp[2] != 0)) {
             /* Error getting event, probably done. */
             msg->done(msg);
 
             /* Take off the msg flag. */
             ssif_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
             handle_flags(ssif_info, flags);
         } else if (msg->rsp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
                || msg->rsp[1] != IPMI_GET_MSG_CMD) {
             dev_warn(&ssif_info->client->dev,
                  "Invalid response clearing flags: %x %x\n",
                  msg->rsp[0], msg->rsp[1]);
             msg->done(msg);
 
             /* Take off the msg flag. */
             ssif_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
             handle_flags(ssif_info, flags);
         } else {
             ssif_inc_stat(ssif_info, incoming_messages);
             handle_flags(ssif_info, flags);
             deliver_recv_msg(ssif_info, msg);
         }
         break;
 
     default:
         /* Should never happen, but just in case. */
         dev_warn(&ssif_info->client->dev,
              "Invalid state in message done handling: %d\n",
              ssif_info->ssif_state);
         ipmi_ssif_unlock_cond(ssif_info, flags);
     }
 
     flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
     if (SSIF_IDLE(ssif_info) && !ssif_info->stopping) {
         if (ssif_info->req_events)
             start_event_fetch(ssif_info, flags);
         else if (ssif_info->req_flags)
             start_flag_fetch(ssif_info, flags);
         else
             start_next_msg(ssif_info, flags);
     } else
         ipmi_ssif_unlock_cond(ssif_info, flags);
 
     if (ssif_info->ssif_debug & SSIF_DEBUG_STATE)
         dev_dbg(&ssif_info->client->dev,
             "DONE 2: state = %d.\n", ssif_info->ssif_state);
 }
 
 static void msg_written_handler(struct ssif_info *ssif_info, int result,
                 unsigned char *data, unsigned int len)
 {
     /* We are single-threaded here, so no need for a lock. */
     if (result < 0) {
         ssif_info->retries_left--;
         if (ssif_info->retries_left > 0) {
             if (!start_resend(ssif_info)) {
                 ssif_inc_stat(ssif_info, send_retries);
                 return;
             }
             /* request failed, just return the error. */
             ssif_inc_stat(ssif_info, send_errors);
 
             if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
                 dev_dbg(&ssif_info->client->dev,
                     "%s: Out of retries\n", __func__);
             msg_done_handler(ssif_info, -EIO, NULL, 0);
             return;
         }
 
         ssif_inc_stat(ssif_info, send_errors);
 
         /*
          * Got an error on transmit, let the done routine
          * handle it.
          */
         if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
             dev_dbg(&ssif_info->client->dev,
                 "%s: Error  %d\n", __func__, result);
 
         msg_done_handler(ssif_info, result, NULL, 0);
         return;
     }
 
     if (ssif_info->multi_data) {
         /*
          * In the middle of a multi-data write.  See the comment
          * in the SSIF_MULTI_n_PART case in the probe function
          * for details on the intricacies of this.
          */
         int left, to_write;
         unsigned char *data_to_send;
         unsigned char cmd;
 
         ssif_inc_stat(ssif_info, sent_messages_parts);
 
         left = ssif_info->multi_len - ssif_info->multi_pos;
         to_write = left;
         if (to_write > 32)
             to_write = 32;
         /* Length byte. */
         ssif_info->multi_data[ssif_info->multi_pos] = to_write;
         data_to_send = ssif_info->multi_data + ssif_info->multi_pos;
         ssif_info->multi_pos += to_write;
         cmd = SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE;
         if (ssif_info->cmd8_works) {
             if (left == to_write) {
                 cmd = SSIF_IPMI_MULTI_PART_REQUEST_END;
                 ssif_info->multi_data = NULL;
             }
         } else if (to_write < 32) {
             ssif_info->multi_data = NULL;
         }
 
         ssif_i2c_send(ssif_info, msg_written_handler,
               I2C_SMBUS_WRITE, cmd,
               data_to_send, I2C_SMBUS_BLOCK_DATA);
     } else {
         /* Ready to request the result. */
         unsigned long oflags, *flags;
 
         ssif_inc_stat(ssif_info, sent_messages);
         ssif_inc_stat(ssif_info, sent_messages_parts);
 
         flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
         if (ssif_info->got_alert) {
             /* The result is already ready, just start it. */
             ssif_info->got_alert = false;
             ipmi_ssif_unlock_cond(ssif_info, flags);
             start_get(ssif_info);
         } else {
             /* Wait a jiffie then request the next message */
             ssif_info->waiting_alert = true;
             ssif_info->retries_left = SSIF_RECV_RETRIES;
             ssif_info->rtc_us_timer = SSIF_MSG_PART_USEC;
             if (!ssif_info->stopping)
                 mod_timer(&ssif_info->retry_timer,
                       jiffies + SSIF_MSG_PART_JIFFIES);
             ipmi_ssif_unlock_cond(ssif_info, flags);
         }
     }
 }
 
 static int start_resend(struct ssif_info *ssif_info)
 {
     int command;
 
     ssif_info->got_alert = false;
 
     if (ssif_info->data_len > 32) {
         command = SSIF_IPMI_MULTI_PART_REQUEST_START;
         ssif_info->multi_data = ssif_info->data;
         ssif_info->multi_len = ssif_info->data_len;
         /*
          * Subtle thing, this is 32, not 33, because we will
          * overwrite the thing at position 32 (which was just
          * transmitted) with the new length.
          */
         ssif_info->multi_pos = 32;
         ssif_info->data[0] = 32;
     } else {
         ssif_info->multi_data = NULL;
         command = SSIF_IPMI_REQUEST;
         ssif_info->data[0] = ssif_info->data_len;
     }
 
     ssif_i2c_send(ssif_info, msg_written_handler, I2C_SMBUS_WRITE,
            command, ssif_info->data, I2C_SMBUS_BLOCK_DATA);
     return 0;
 }
 
 static int start_send(struct ssif_info *ssif_info,
               unsigned char   *data,
               unsigned int    len)
 {
     if (len > IPMI_MAX_MSG_LENGTH)
         return -E2BIG;
     if (len > ssif_info->max_xmit_msg_size)
         return -E2BIG;
 
     ssif_info->retries_left = SSIF_SEND_RETRIES;
     memcpy(ssif_info->data + 1, data, len);
     ssif_info->data_len = len;
     return start_resend(ssif_info);
 }
 
 /* Must be called with the message lock held. */
 static void start_next_msg(struct ssif_info *ssif_info, unsigned long *flags)
 {
     struct ipmi_smi_msg *msg;
     unsigned long oflags;
 
  restart:
     if (!SSIF_IDLE(ssif_info)) {
         ipmi_ssif_unlock_cond(ssif_info, flags);
         return;
     }
 
     if (!ssif_info->waiting_msg) {
         ssif_info->curr_msg = NULL;
         ipmi_ssif_unlock_cond(ssif_info, flags);
     } else {
         int rv;
 
         ssif_info->curr_msg = ssif_info->waiting_msg;
         ssif_info->waiting_msg = NULL;
         ipmi_ssif_unlock_cond(ssif_info, flags);
         rv = start_send(ssif_info,
                 ssif_info->curr_msg->data,
                 ssif_info->curr_msg->data_size);
         if (rv) {
             msg = ssif_info->curr_msg;
             ssif_info->curr_msg = NULL;
             return_hosed_msg(ssif_info, msg);
             flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
             goto restart;
         }
     }
 }
 
 static void sender(void                *send_info,
            struct ipmi_smi_msg *msg)
 {
     struct ssif_info *ssif_info = send_info;
     unsigned long oflags, *flags;
 
     BUG_ON(ssif_info->waiting_msg);
     ssif_info->waiting_msg = msg;
 
     flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
     start_next_msg(ssif_info, flags);
 
     if (ssif_info->ssif_debug & SSIF_DEBUG_TIMING) {
         struct timespec64 t;
 
         ktime_get_real_ts64(&t);
         dev_dbg(&ssif_info->client->dev,
             "**Enqueue %02x %02x: %lld.%6.6ld\n",
             msg->data[0], msg->data[1],
             (long long)t.tv_sec, (long)t.tv_nsec / NSEC_PER_USEC);
     }
 }
 
 static int get_smi_info(void *send_info, struct ipmi_smi_info *data)
 {
     struct ssif_info *ssif_info = send_info;
 
     data->addr_src = ssif_info->addr_source;
     data->dev = &ssif_info->client->dev;
     data->addr_info = ssif_info->addr_info;
     get_device(data->dev);
 
     return 0;
 }
 
 /*
  * Upper layer wants us to request events.
  */
 static void request_events(void *send_info)
 {
     struct ssif_info *ssif_info = send_info;
     unsigned long oflags, *flags;
 
     if (!ssif_info->has_event_buffer)
         return;
 
     flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
     ssif_info->req_events = true;
     ipmi_ssif_unlock_cond(ssif_info, flags);
 }
 
 /*
  * Upper layer is changing the flag saying whether we need to request
  * flags periodically or not.
  */
 static void ssif_set_need_watch(void *send_info, unsigned int watch_mask)
 {
     struct ssif_info *ssif_info = send_info;
     unsigned long oflags, *flags;
     long timeout = 0;
 
     if (watch_mask & IPMI_WATCH_MASK_CHECK_MESSAGES)
         timeout = SSIF_WATCH_MSG_TIMEOUT;
     else if (watch_mask)
         timeout = SSIF_WATCH_WATCHDOG_TIMEOUT;
 
     flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
     if (timeout != ssif_info->watch_timeout) {
         ssif_info->watch_timeout = timeout;
         if (ssif_info->watch_timeout)
             mod_timer(&ssif_info->watch_timer,
                   jiffies + ssif_info->watch_timeout);
     }
     ipmi_ssif_unlock_cond(ssif_info, flags);
 }
 
 static int ssif_start_processing(void            *send_info,
                  struct ipmi_smi *intf)
 {
     struct ssif_info *ssif_info = send_info;
 
     ssif_info->intf = intf;
 
     return 0;
 }
 
 #define MAX_SSIF_BMCS 4
 
 static unsigned short addr[MAX_SSIF_BMCS];
 static int num_addrs;
 module_param_array(addr, ushort, &num_addrs, 0);
 MODULE_PARM_DESC(addr, "The addresses to scan for IPMI BMCs on the SSIFs.");
 
 static char *adapter_name[MAX_SSIF_BMCS];
 static int num_adapter_names;
 module_param_array(adapter_name, charp, &num_adapter_names, 0);
 MODULE_PARM_DESC(adapter_name, "The string name of the I2C device that has the BMC.  By default all devices are scanned.");
 
 static int slave_addrs[MAX_SSIF_BMCS];
 static int num_slave_addrs;
 module_param_array(slave_addrs, int, &num_slave_addrs, 0);
 MODULE_PARM_DESC(slave_addrs,
          "The default IPMB slave address for the controller.");
 
 static bool alerts_broken;
 module_param(alerts_broken, bool, 0);
 MODULE_PARM_DESC(alerts_broken, "Don't enable alerts for the controller.");
 
 /*
  * Bit 0 enables message debugging, bit 1 enables state debugging, and
  * bit 2 enables timing debugging.  This is an array indexed by
  * interface number"
  */
 static int dbg[MAX_SSIF_BMCS];
 static int num_dbg;
 module_param_array(dbg, int, &num_dbg, 0);
 MODULE_PARM_DESC(dbg, "Turn on debugging.");
 
 static bool ssif_dbg_probe;
 module_param_named(dbg_probe, ssif_dbg_probe, bool, 0);
 MODULE_PARM_DESC(dbg_probe, "Enable debugging of probing of adapters.");
 
 static bool ssif_tryacpi = true;
 module_param_named(tryacpi, ssif_tryacpi, bool, 0);
 MODULE_PARM_DESC(tryacpi, "Setting this to zero will disable the default scan of the interfaces identified via ACPI");
 
 static bool ssif_trydmi = true;
 module_param_named(trydmi, ssif_trydmi, bool, 0);
 MODULE_PARM_DESC(trydmi, "Setting this to zero will disable the default scan of the interfaces identified via DMI (SMBIOS)");
 
 static DEFINE_MUTEX(ssif_infos_mutex);
 static LIST_HEAD(ssif_infos);
 
 #define IPMI_SSIF_ATTR(name) \
 static ssize_t ipmi_##name##_show(struct device *dev,           \
                   struct device_attribute *attr,    \
                   char *buf)                \
 {                                   \
     struct ssif_info *ssif_info = dev_get_drvdata(dev);     \
                                     \
     return sysfs_emit(buf, "%u\n", ssif_get_stat(ssif_info, name));\
 }                                   \
 static DEVICE_ATTR(name, S_IRUGO, ipmi_##name##_show, NULL)
 
 static ssize_t ipmi_type_show(struct device *dev,
                   struct device_attribute *attr,
                   char *buf)
 {
     return sysfs_emit(buf, "ssif\n");
 }
 static DEVICE_ATTR(type, S_IRUGO, ipmi_type_show, NULL);
 
 IPMI_SSIF_ATTR(sent_messages);
 IPMI_SSIF_ATTR(sent_messages_parts);
 IPMI_SSIF_ATTR(send_retries);
 IPMI_SSIF_ATTR(send_errors);
 IPMI_SSIF_ATTR(received_messages);
 IPMI_SSIF_ATTR(received_message_parts);
 IPMI_SSIF_ATTR(receive_retries);
 IPMI_SSIF_ATTR(receive_errors);
 IPMI_SSIF_ATTR(flag_fetches);
 IPMI_SSIF_ATTR(hosed);
 IPMI_SSIF_ATTR(events);
 IPMI_SSIF_ATTR(watchdog_pretimeouts);
 IPMI_SSIF_ATTR(alerts);
 
 static struct attribute *ipmi_ssif_dev_attrs[] = {
     &dev_attr_type.attr,
     &dev_attr_sent_messages.attr,
     &dev_attr_sent_messages_parts.attr,
     &dev_attr_send_retries.attr,
     &dev_attr_send_errors.attr,
     &dev_attr_received_messages.attr,
     &dev_attr_received_message_parts.attr,
     &dev_attr_receive_retries.attr,
     &dev_attr_receive_errors.attr,
     &dev_attr_flag_fetches.attr,
     &dev_attr_hosed.attr,
     &dev_attr_events.attr,
     &dev_attr_watchdog_pretimeouts.attr,
     &dev_attr_alerts.attr,
     NULL
 };
 
 static const struct attribute_group ipmi_ssif_dev_attr_group = {
     .attrs      = ipmi_ssif_dev_attrs,
 };
 
 static void shutdown_ssif(void *send_info)
 {
     struct ssif_info *ssif_info = send_info;
 
     device_remove_group(&ssif_info->client->dev, &ipmi_ssif_dev_attr_group);
     dev_set_drvdata(&ssif_info->client->dev, NULL);
 
     /* make sure the driver is not looking for flags any more. */
     while (ssif_info->ssif_state != SSIF_NORMAL)
         schedule_timeout(1);
 
     ssif_info->stopping = true;
     del_timer_sync(&ssif_info->watch_timer);
     del_timer_sync(&ssif_info->retry_timer);
     if (ssif_info->thread) {
         complete(&ssif_info->wake_thread);
         kthread_stop(ssif_info->thread);
     }
 }
 
 static int ssif_remove(struct i2c_client *client)
 {
     struct ssif_info *ssif_info = i2c_get_clientdata(client);
     struct ssif_addr_info *addr_info;
 
     if (!ssif_info)
         return 0;
 
     /*
      * After this point, we won't deliver anything asychronously
      * to the message handler.  We can unregister ourself.
      */
     ipmi_unregister_smi(ssif_info->intf);
 
     list_for_each_entry(addr_info, &ssif_infos, link) {
         if (addr_info->client == client) {
             addr_info->client = NULL;
             break;
         }
     }
 
     kfree(ssif_info);
 
     return 0;
 }
 
 static int read_response(struct i2c_client *client, unsigned char *resp)
 {
     int ret = -ENODEV, retry_cnt = SSIF_RECV_RETRIES;
 
     while (retry_cnt > 0) {
         ret = i2c_smbus_read_block_data(client, SSIF_IPMI_RESPONSE,
                         resp);
         if (ret > 0)
             break;
         msleep(SSIF_MSG_MSEC);
         retry_cnt--;
         if (retry_cnt <= 0)
             break;
     }
 
     return ret;
 }
 
 static int do_cmd(struct i2c_client *client, int len, unsigned char *msg,
           int *resp_len, unsigned char *resp)
 {
     int retry_cnt;
     int ret;
 
     retry_cnt = SSIF_SEND_RETRIES;
  retry1:
     ret = i2c_smbus_write_block_data(client, SSIF_IPMI_REQUEST, len, msg);
     if (ret) {
         retry_cnt--;
         if (retry_cnt > 0)
             goto retry1;
         return -ENODEV;
     }
 
     ret = read_response(client, resp);
     if (ret > 0) {
         /* Validate that the response is correct. */
         if (ret < 3 ||
             (resp[0] != (msg[0] | (1 << 2))) ||
             (resp[1] != msg[1]))
             ret = -EINVAL;
         else if (ret > IPMI_MAX_MSG_LENGTH) {
             ret = -E2BIG;
         } else {
             *resp_len = ret;
             ret = 0;
         }
     }
 
     return ret;
 }
 
 static int ssif_detect(struct i2c_client *client, struct i2c_board_info *info)
 {
     unsigned char *resp;
     unsigned char msg[3];
     int           rv;
     int           len;
 
     resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
     if (!resp)
         return -ENOMEM;
 
     /* Do a Get Device ID command, since it is required. */
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_GET_DEVICE_ID_CMD;
     rv = do_cmd(client, 2, msg, &len, resp);
     if (rv)
         rv = -ENODEV;
     else
         strscpy(info->type, DEVICE_NAME, I2C_NAME_SIZE);
     kfree(resp);
     return rv;
 }
 
 static int strcmp_nospace(char *s1, char *s2)
 {
     while (*s1 && *s2) {
         while (isspace(*s1))
             s1++;
         while (isspace(*s2))
             s2++;
         if (*s1 > *s2)
             return 1;
         if (*s1 < *s2)
             return -1;
         s1++;
         s2++;
     }
     return 0;
 }
 
 static struct ssif_addr_info *ssif_info_find(unsigned short addr,
                          char *adapter_name,
                          bool match_null_name)
 {
     struct ssif_addr_info *info, *found = NULL;
 
 restart:
     list_for_each_entry(info, &ssif_infos, link) {
         if (info->binfo.addr == addr) {
             if (info->addr_src == SI_SMBIOS)
                 info->adapter_name = kstrdup(adapter_name,
                                  GFP_KERNEL);
 
             if (info->adapter_name || adapter_name) {
                 if (!info->adapter_name != !adapter_name) {
                     /* One is NULL and one is not */
                     continue;
                 }
                 if (adapter_name &&
                     strcmp_nospace(info->adapter_name,
                            adapter_name))
                     /* Names do not match */
                     continue;
             }
             found = info;
             break;
         }
     }
 
     if (!found && match_null_name) {
         /* Try to get an exact match first, then try with a NULL name */
         adapter_name = NULL;
         match_null_name = false;
         goto restart;
     }
 
     return found;
 }
 
 static bool check_acpi(struct ssif_info *ssif_info, struct device *dev)
 {
 #ifdef CONFIG_ACPI
     acpi_handle acpi_handle;
 
     acpi_handle = ACPI_HANDLE(dev);
     if (acpi_handle) {
         ssif_info->addr_source = SI_ACPI;
         ssif_info->addr_info.acpi_info.acpi_handle = acpi_handle;
         request_module("acpi_ipmi");
         return true;
     }
 #endif
     return false;
 }
 
 static int find_slave_address(struct i2c_client *client, int slave_addr)
 {
 #ifdef CONFIG_IPMI_DMI_DECODE
     if (!slave_addr)
         slave_addr = ipmi_dmi_get_slave_addr(
             SI_TYPE_INVALID,
             i2c_adapter_id(client->adapter),
             client->addr);
 #endif
 
     return slave_addr;
 }
 
 static int start_multipart_test(struct i2c_client *client,
                 unsigned char *msg, bool do_middle)
 {
     int retry_cnt = SSIF_SEND_RETRIES, ret;
 
 retry_write:
     ret = i2c_smbus_write_block_data(client,
                      SSIF_IPMI_MULTI_PART_REQUEST_START,
                      32, msg);
     if (ret) {
         retry_cnt--;
         if (retry_cnt > 0)
             goto retry_write;
         dev_err(&client->dev, "Could not write multi-part start, though the BMC said it could handle it.  Just limit sends to one part.\n");
         return ret;
     }
 
     if (!do_middle)
         return 0;
 
     ret = i2c_smbus_write_block_data(client,
                      SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE,
                      32, msg + 32);
     if (ret) {
         dev_err(&client->dev, "Could not write multi-part middle, though the BMC said it could handle it.  Just limit sends to one part.\n");
         return ret;
     }
 
     return 0;
 }
 
 static void test_multipart_messages(struct i2c_client *client,
                     struct ssif_info *ssif_info,
                     unsigned char *resp)
 {
     unsigned char msg[65];
     int ret;
     bool do_middle;
 
     if (ssif_info->max_xmit_msg_size <= 32)
         return;
 
     do_middle = ssif_info->max_xmit_msg_size > 63;
 
     memset(msg, 0, sizeof(msg));
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_GET_DEVICE_ID_CMD;
 
     /*
      * The specification is all messed up dealing with sending
      * multi-part messages.  Per what the specification says, it
      * is impossible to send a message that is a multiple of 32
      * bytes, except for 32 itself.  It talks about a "start"
      * transaction (cmd=6) that must be 32 bytes, "middle"
      * transaction (cmd=7) that must be 32 bytes, and an "end"
      * transaction.  The "end" transaction is shown as cmd=7 in
      * the text, but if that's the case there is no way to
      * differentiate between a middle and end part except the
      * length being less than 32.  But there is a table at the far
      * end of the section (that I had never noticed until someone
      * pointed it out to me) that mentions it as cmd=8.
      *
      * After some thought, I think the example is wrong and the
      * end transaction should be cmd=8.  But some systems don't
      * implement cmd=8, they use a zero-length end transaction,
      * even though that violates the SMBus specification.
      *
      * So, to work around this, this code tests if cmd=8 works.
      * If it does, then we use that.  If not, it tests zero-
      * byte end transactions.  If that works, good.  If not,
      * we only allow 63-byte transactions max.
      */
 
     ret = start_multipart_test(client, msg, do_middle);
     if (ret)
         goto out_no_multi_part;
 
     ret = i2c_smbus_write_block_data(client,
                      SSIF_IPMI_MULTI_PART_REQUEST_END,
                      1, msg + 64);
 
     if (!ret)
         ret = read_response(client, resp);
 
     if (ret > 0) {
         /* End transactions work, we are good. */
         ssif_info->cmd8_works = true;
         return;
     }
 
     ret = start_multipart_test(client, msg, do_middle);
     if (ret) {
         dev_err(&client->dev, "Second multipart test failed.\n");
         goto out_no_multi_part;
     }
 
     ret = i2c_smbus_write_block_data(client,
                      SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE,
                      0, msg + 64);
     if (!ret)
         ret = read_response(client, resp);
     if (ret > 0)
         /* Zero-size end parts work, use those. */
         return;
 
     /* Limit to 63 bytes and use a short middle command to mark the end. */
     if (ssif_info->max_xmit_msg_size > 63)
         ssif_info->max_xmit_msg_size = 63;
     return;
 
 out_no_multi_part:
     ssif_info->max_xmit_msg_size = 32;
     return;
 }
 
 /*
  * 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 void ssif_remove_dup(struct i2c_client *client)
 {
     struct ssif_info *ssif_info = i2c_get_clientdata(client);
 
     ipmi_unregister_smi(ssif_info->intf);
     kfree(ssif_info);
 }
 
 static int ssif_add_infos(struct i2c_client *client)
 {
     struct ssif_addr_info *info;
 
     info = kzalloc(sizeof(*info), GFP_KERNEL);
     if (!info)
         return -ENOMEM;
     info->addr_src = SI_ACPI;
     info->client = client;
     info->adapter_name = kstrdup(client->adapter->name, GFP_KERNEL);
     info->binfo.addr = client->addr;
     list_add_tail(&info->link, &ssif_infos);
     return 0;
 }
 
 /*
  * Prefer ACPI over SMBIOS, if both are available.
  * So if we get an ACPI interface and have already registered a SMBIOS
  * interface at the same address, remove the SMBIOS and add the ACPI one.
  */
 static int ssif_check_and_remove(struct i2c_client *client,
                   struct ssif_info *ssif_info)
 {
     struct ssif_addr_info *info;
 
     list_for_each_entry(info, &ssif_infos, link) {
         if (!info->client)
             return 0;
         if (!strcmp(info->adapter_name, client->adapter->name) &&
             info->binfo.addr == client->addr) {
             if (info->addr_src == SI_ACPI)
                 return -EEXIST;
 
             if (ssif_info->addr_source == SI_ACPI &&
                 info->addr_src == SI_SMBIOS) {
                 dev_info(&client->dev,
                      "Removing %s-specified SSIF interface in favor of ACPI\n",
                      ipmi_addr_src_to_str(info->addr_src));
                 ssif_remove_dup(info->client);
                 return 0;
             }
         }
     }
     return 0;
 }
 
 static int ssif_probe(struct i2c_client *client)
 {
     unsigned char     msg[3];
     unsigned char     *resp;
     struct ssif_info   *ssif_info;
     int               rv = 0;
     int               len = 0;
     int               i;
     u8        slave_addr = 0;
     struct ssif_addr_info *addr_info = NULL;
 
     mutex_lock(&ssif_infos_mutex);
     resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
     if (!resp) {
         mutex_unlock(&ssif_infos_mutex);
         return -ENOMEM;
     }
 
     ssif_info = kzalloc(sizeof(*ssif_info), GFP_KERNEL);
     if (!ssif_info) {
         kfree(resp);
         mutex_unlock(&ssif_infos_mutex);
         return -ENOMEM;
     }
 
     if (!check_acpi(ssif_info, &client->dev)) {
         addr_info = ssif_info_find(client->addr, client->adapter->name,
                        true);
         if (!addr_info) {
             /* Must have come in through sysfs. */
             ssif_info->addr_source = SI_HOTMOD;
         } else {
             ssif_info->addr_source = addr_info->addr_src;
             ssif_info->ssif_debug = addr_info->debug;
             ssif_info->addr_info = addr_info->addr_info;
             addr_info->client = client;
             slave_addr = addr_info->slave_addr;
         }
     }
 
     ssif_info->client = client;
     i2c_set_clientdata(client, ssif_info);
 
     rv = ssif_check_and_remove(client, ssif_info);
     /* If rv is 0 and addr source is not SI_ACPI, continue probing */
     if (!rv && ssif_info->addr_source == SI_ACPI) {
         rv = ssif_add_infos(client);
         if (rv) {
             dev_err(&client->dev, "Out of memory!, exiting ..\n");
             goto out;
         }
     } else if (rv) {
         dev_err(&client->dev, "Not probing, Interface already present\n");
         goto out;
     }
 
     slave_addr = find_slave_address(client, slave_addr);
 
     dev_info(&client->dev,
          "Trying %s-specified SSIF interface at i2c address 0x%x, adapter %s, slave address 0x%x\n",
         ipmi_addr_src_to_str(ssif_info->addr_source),
         client->addr, client->adapter->name, slave_addr);
 
     /* Now check for system interface capabilities */
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_GET_SYSTEM_INTERFACE_CAPABILITIES_CMD;
     msg[2] = 0; /* SSIF */
     rv = do_cmd(client, 3, msg, &len, resp);
     if (!rv && (len >= 3) && (resp[2] == 0)) {
         if (len < 7) {
             if (ssif_dbg_probe)
                 dev_dbg(&ssif_info->client->dev,
                     "SSIF info too short: %d\n", len);
             goto no_support;
         }
 
         /* Got a good SSIF response, handle it. */
         ssif_info->max_xmit_msg_size = resp[5];
         ssif_info->max_recv_msg_size = resp[6];
         ssif_info->multi_support = (resp[4] >> 6) & 0x3;
         ssif_info->supports_pec = (resp[4] >> 3) & 0x1;
 
         /* Sanitize the data */
         switch (ssif_info->multi_support) {
         case SSIF_NO_MULTI:
             if (ssif_info->max_xmit_msg_size > 32)
                 ssif_info->max_xmit_msg_size = 32;
             if (ssif_info->max_recv_msg_size > 32)
                 ssif_info->max_recv_msg_size = 32;
             break;
 
         case SSIF_MULTI_2_PART:
             if (ssif_info->max_xmit_msg_size > 63)
                 ssif_info->max_xmit_msg_size = 63;
             if (ssif_info->max_recv_msg_size > 62)
                 ssif_info->max_recv_msg_size = 62;
             break;
 
         case SSIF_MULTI_n_PART:
             /* We take whatever size given, but do some testing. */
             break;
 
         default:
             /* Data is not sane, just give up. */
             goto no_support;
         }
     } else {
  no_support:
         /* Assume no multi-part or PEC support */
         dev_info(&ssif_info->client->dev,
              "Error fetching SSIF: %d %d %2.2x, your system probably doesn't support this command so using defaults\n",
             rv, len, resp[2]);
 
         ssif_info->max_xmit_msg_size = 32;
         ssif_info->max_recv_msg_size = 32;
         ssif_info->multi_support = SSIF_NO_MULTI;
         ssif_info->supports_pec = 0;
     }
 
     test_multipart_messages(client, ssif_info, resp);
 
     /* Make sure the NMI timeout is cleared. */
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_CLEAR_MSG_FLAGS_CMD;
     msg[2] = WDT_PRE_TIMEOUT_INT;
     rv = do_cmd(client, 3, msg, &len, resp);
     if (rv || (len < 3) || (resp[2] != 0))
         dev_warn(&ssif_info->client->dev,
              "Unable to clear message flags: %d %d %2.2x\n",
              rv, len, resp[2]);
 
     /* Attempt to enable the event buffer. */
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_GET_BMC_GLOBAL_ENABLES_CMD;
     rv = do_cmd(client, 2, msg, &len, resp);
     if (rv || (len < 4) || (resp[2] != 0)) {
         dev_warn(&ssif_info->client->dev,
              "Error getting global enables: %d %d %2.2x\n",
              rv, len, resp[2]);
         rv = 0; /* Not fatal */
         goto found;
     }
 
     ssif_info->global_enables = resp[3];
 
     if (resp[3] & IPMI_BMC_EVT_MSG_BUFF) {
         ssif_info->has_event_buffer = true;
         /* buffer is already enabled, nothing to do. */
         goto found;
     }
 
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
     msg[2] = ssif_info->global_enables | IPMI_BMC_EVT_MSG_BUFF;
     rv = do_cmd(client, 3, msg, &len, resp);
     if (rv || (len < 2)) {
         dev_warn(&ssif_info->client->dev,
              "Error setting global enables: %d %d %2.2x\n",
              rv, len, resp[2]);
         rv = 0; /* Not fatal */
         goto found;
     }
 
     if (resp[2] == 0) {
         /* A successful return means the event buffer is supported. */
         ssif_info->has_event_buffer = true;
         ssif_info->global_enables |= IPMI_BMC_EVT_MSG_BUFF;
     }
 
     /* Some systems don't behave well if you enable alerts. */
     if (alerts_broken)
         goto found;
 
     msg[0] = IPMI_NETFN_APP_REQUEST << 2;
     msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
     msg[2] = ssif_info->global_enables | IPMI_BMC_RCV_MSG_INTR;
     rv = do_cmd(client, 3, msg, &len, resp);
     if (rv || (len < 2)) {
         dev_warn(&ssif_info->client->dev,
              "Error setting global enables: %d %d %2.2x\n",
              rv, len, resp[2]);
         rv = 0; /* Not fatal */
         goto found;
     }
 
     if (resp[2] == 0) {
         /* A successful return means the alert is supported. */
         ssif_info->supports_alert = true;
         ssif_info->global_enables |= IPMI_BMC_RCV_MSG_INTR;
     }
 
  found:
     if (ssif_dbg_probe) {
         dev_dbg(&ssif_info->client->dev,
                "%s: i2c_probe found device at i2c address %x\n",
                __func__, client->addr);
     }
 
     spin_lock_init(&ssif_info->lock);
     ssif_info->ssif_state = SSIF_NORMAL;
     timer_setup(&ssif_info->retry_timer, retry_timeout, 0);
     timer_setup(&ssif_info->watch_timer, watch_timeout, 0);
 
     for (i = 0; i < SSIF_NUM_STATS; i++)
         atomic_set(&ssif_info->stats[i], 0);
 
     if (ssif_info->supports_pec)
         ssif_info->client->flags |= I2C_CLIENT_PEC;
 
     ssif_info->handlers.owner = THIS_MODULE;
     ssif_info->handlers.start_processing = ssif_start_processing;
     ssif_info->handlers.shutdown = shutdown_ssif;
     ssif_info->handlers.get_smi_info = get_smi_info;
     ssif_info->handlers.sender = sender;
     ssif_info->handlers.request_events = request_events;
     ssif_info->handlers.set_need_watch = ssif_set_need_watch;
 
     {
         unsigned int thread_num;
 
         thread_num = ((i2c_adapter_id(ssif_info->client->adapter)
                    << 8) |
                   ssif_info->client->addr);
         init_completion(&ssif_info->wake_thread);
         ssif_info->thread = kthread_run(ipmi_ssif_thread, ssif_info,
                            "kssif%4.4x", thread_num);
         if (IS_ERR(ssif_info->thread)) {
             rv = PTR_ERR(ssif_info->thread);
             dev_notice(&ssif_info->client->dev,
                    "Could not start kernel thread: error %d\n",
                    rv);
             goto out;
         }
     }
 
     dev_set_drvdata(&ssif_info->client->dev, ssif_info);
     rv = device_add_group(&ssif_info->client->dev,
                   &ipmi_ssif_dev_attr_group);
     if (rv) {
         dev_err(&ssif_info->client->dev,
             "Unable to add device attributes: error %d\n",
             rv);
         goto out;
     }
 
     rv = ipmi_register_smi(&ssif_info->handlers,
                    ssif_info,
                    &ssif_info->client->dev,
                    slave_addr);
     if (rv) {
         dev_err(&ssif_info->client->dev,
             "Unable to register device: error %d\n", rv);
         goto out_remove_attr;
     }
 
  out:
     if (rv) {
         if (addr_info)
             addr_info->client = NULL;
 
         dev_err(&ssif_info->client->dev,
             "Unable to start IPMI SSIF: %d\n", rv);
         i2c_set_clientdata(client, NULL);
         kfree(ssif_info);
     }
     kfree(resp);
     mutex_unlock(&ssif_infos_mutex);
     return rv;
 
 out_remove_attr:
     device_remove_group(&ssif_info->client->dev, &ipmi_ssif_dev_attr_group);
     dev_set_drvdata(&ssif_info->client->dev, NULL);
     goto out;
 }
 
 static int new_ssif_client(int addr, char *adapter_name,
                int debug, int slave_addr,
                enum ipmi_addr_src addr_src,
                struct device *dev)
 {
     struct ssif_addr_info *addr_info;
     int rv = 0;
 
     mutex_lock(&ssif_infos_mutex);
     if (ssif_info_find(addr, adapter_name, false)) {
         rv = -EEXIST;
         goto out_unlock;
     }
 
     addr_info = kzalloc(sizeof(*addr_info), GFP_KERNEL);
     if (!addr_info) {
         rv = -ENOMEM;
         goto out_unlock;
     }
 
     if (adapter_name) {
         addr_info->adapter_name = kstrdup(adapter_name, GFP_KERNEL);
         if (!addr_info->adapter_name) {
             kfree(addr_info);
             rv = -ENOMEM;
             goto out_unlock;
         }
     }
 
     strncpy(addr_info->binfo.type, DEVICE_NAME,
         sizeof(addr_info->binfo.type));
     addr_info->binfo.addr = addr;
     addr_info->binfo.platform_data = addr_info;
     addr_info->debug = debug;
     addr_info->slave_addr = slave_addr;
     addr_info->addr_src = addr_src;
     addr_info->dev = dev;
 
     if (dev)
         dev_set_drvdata(dev, addr_info);
 
     list_add_tail(&addr_info->link, &ssif_infos);
 
     /* Address list will get it */
 
 out_unlock:
     mutex_unlock(&ssif_infos_mutex);
     return rv;
 }
 
 static void free_ssif_clients(void)
 {
     struct ssif_addr_info *info, *tmp;
 
     mutex_lock(&ssif_infos_mutex);
     list_for_each_entry_safe(info, tmp, &ssif_infos, link) {
         list_del(&info->link);
         kfree(info->adapter_name);
         kfree(info);
     }
     mutex_unlock(&ssif_infos_mutex);
 }
 
 static unsigned short *ssif_address_list(void)
 {
     struct ssif_addr_info *info;
     unsigned int count = 0, i = 0;
     unsigned short *address_list;
 
     list_for_each_entry(info, &ssif_infos, link)
         count++;
 
     address_list = kcalloc(count + 1, sizeof(*address_list),
                    GFP_KERNEL);
     if (!address_list)
         return NULL;
 
     list_for_each_entry(info, &ssif_infos, link) {
         unsigned short addr = info->binfo.addr;
         int j;
 
         for (j = 0; j < i; j++) {
             if (address_list[j] == addr)
                 /* Found a dup. */
                 break;
         }
         if (j == i) /* Didn't find it in the list. */
             address_list[i++] = addr;
     }
     address_list[i] = I2C_CLIENT_END;
 
     return address_list;
 }
 
 #ifdef CONFIG_ACPI
 static const struct acpi_device_id ssif_acpi_match[] = {
     { "IPI0001", 0 },
     { },
 };
 MODULE_DEVICE_TABLE(acpi, ssif_acpi_match);
 #endif
 
 #ifdef CONFIG_DMI
 static int dmi_ipmi_probe(struct platform_device *pdev)
 {
     u8 slave_addr = 0;
     u16 i2c_addr;
     int rv;
 
     if (!ssif_trydmi)
         return -ENODEV;
 
     rv = device_property_read_u16(&pdev->dev, "i2c-addr", &i2c_addr);
     if (rv) {
         dev_warn(&pdev->dev, "No i2c-addr property\n");
         return -ENODEV;
     }
 
     rv = device_property_read_u8(&pdev->dev, "slave-addr", &slave_addr);
     if (rv)
         slave_addr = 0x20;
 
     return new_ssif_client(i2c_addr, NULL, 0,
                    slave_addr, SI_SMBIOS, &pdev->dev);
 }
 #else
 static int dmi_ipmi_probe(struct platform_device *pdev)
 {
     return -ENODEV;
 }
 #endif
 
 static const struct i2c_device_id ssif_id[] = {
     { DEVICE_NAME, 0 },
     { }
 };
 MODULE_DEVICE_TABLE(i2c, ssif_id);
 
 static struct i2c_driver ssif_i2c_driver = {
     .class      = I2C_CLASS_HWMON,
     .driver     = {
         .name           = DEVICE_NAME
     },
     .probe_new  = ssif_probe,
     .remove     = ssif_remove,
     .alert      = ssif_alert,
     .id_table   = ssif_id,
     .detect     = ssif_detect
 };
 
 static int ssif_platform_probe(struct platform_device *dev)
 {
     return dmi_ipmi_probe(dev);
 }
 
 static int ssif_platform_remove(struct platform_device *dev)
 {
     struct ssif_addr_info *addr_info = dev_get_drvdata(&dev->dev);
 
     if (!addr_info)
         return 0;
 
     mutex_lock(&ssif_infos_mutex);
     list_del(&addr_info->link);
     kfree(addr_info);
     mutex_unlock(&ssif_infos_mutex);
     return 0;
 }
 
 static const struct platform_device_id ssif_plat_ids[] = {
     { "dmi-ipmi-ssif", 0 },
     { }
 };
 
 static struct platform_driver ipmi_driver = {
     .driver = {
         .name = DEVICE_NAME,
     },
     .probe      = ssif_platform_probe,
     .remove     = ssif_platform_remove,
     .id_table       = ssif_plat_ids
 };
 
 static int init_ipmi_ssif(void)
 {
     int i;
     int rv;
 
     if (initialized)
         return 0;
 
     pr_info("IPMI SSIF Interface driver\n");
 
     /* build list for i2c from addr list */
     for (i = 0; i < num_addrs; i++) {
         rv = new_ssif_client(addr[i], adapter_name[i],
                      dbg[i], slave_addrs[i],
                      SI_HARDCODED, NULL);
         if (rv)
             pr_err("Couldn't add hardcoded device at addr 0x%x\n",
                    addr[i]);
     }
 
     if (ssif_tryacpi)
         ssif_i2c_driver.driver.acpi_match_table =
             ACPI_PTR(ssif_acpi_match);
 
     if (ssif_trydmi) {
         rv = platform_driver_register(&ipmi_driver);
         if (rv)
             pr_err("Unable to register driver: %d\n", rv);
         else
             platform_registered = true;
     }
 
     ssif_i2c_driver.address_list = ssif_address_list();
 
     rv = i2c_add_driver(&ssif_i2c_driver);
     if (!rv)
         initialized = true;
 
     return rv;
 }
 module_init(init_ipmi_ssif);
 
 static void cleanup_ipmi_ssif(void)
 {
     if (!initialized)
         return;
 
     initialized = false;
 
     i2c_del_driver(&ssif_i2c_driver);
 
     kfree(ssif_i2c_driver.address_list);
 
     if (ssif_trydmi && platform_registered)
         platform_driver_unregister(&ipmi_driver);
 
     free_ssif_clients();
 }
 module_exit(cleanup_ipmi_ssif);
 
 MODULE_ALIAS("platform:dmi-ipmi-ssif");
 MODULE_AUTHOR("Todd C Davis <todd.c.davis@intel.com>, Corey Minyard <minyard@acm.org>");
 MODULE_DESCRIPTION("IPMI driver for management controllers on a SMBus");
 MODULE_LICENSE("GPL");

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