kernel/drivers/char/ipmi/ipmi_ssif.c

   1 /*
   2  * ipmi_ssif.c
   3  *
   4  * The interface to the IPMI driver for SMBus access to a SMBus
   5  * compliant device.  Called SSIF by the IPMI spec.
   6  *
   7  * Author: Intel Corporation
   8  *         Todd Davis <todd.c.davis@intel.com>
   9  *
  10  * Rewritten by Corey Minyard <minyard@acm.org> to support the
  11  * non-blocking I2C interface, add support for multi-part
  12  * transactions, add PEC support, and general clenaup.
  13  *
  14  * Copyright 2003 Intel Corporation
  15  * Copyright 2005 MontaVista Software
  16  *
  17  *  This program is free software; you can redistribute it and/or modify it
  18  *  under the terms of the GNU General Public License as published by the
  19  *  Free Software Foundation; either version 2 of the License, or (at your
  20  *  option) any later version.
  21  */
  22
  23 /*
  24  * This file holds the "policy" for the interface to the SSIF state
  25  * machine.  It does the configuration, handles timers and interrupts,
  26  * and drives the real SSIF state machine.
  27  */
  28
  29 /*
  30  * TODO: Figure out how to use SMB alerts.  This will require a new
  31  * interface into the I2C driver, I believe.
  32  */
  33
  34 #if defined(MODVERSIONS)
  35 #include <linux/modversions.h>
  36 #endif
  37
  38 #include <linux/module.h>
  39 #include <linux/moduleparam.h>
  40 #include <linux/sched.h>
  41 #include <linux/seq_file.h>
  42 #include <linux/timer.h>
  43 #include <linux/delay.h>
  44 #include <linux/errno.h>
  45 #include <linux/spinlock.h>
  46 #include <linux/slab.h>
  47 #include <linux/list.h>
  48 #include <linux/i2c.h>
  49 #include <linux/ipmi_smi.h>
  50 #include <linux/init.h>
  51 #include <linux/dmi.h>
  52 #include <linux/kthread.h>
  53 #include <linux/acpi.h>
  54 #include <linux/ctype.h>
  55 #include <linux/time64.h>
  56
  57 #define PFX "ipmi_ssif: "
  58 #define DEVICE_NAME "ipmi_ssif"
  59
  60 #define IPMI_GET_SYSTEM_INTERFACE_CAPABILITIES_CMD      0x57
  61
  62 #define SSIF_IPMI_REQUEST                       2
  63 #define SSIF_IPMI_MULTI_PART_REQUEST_START      6
  64 #define SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE     7
  65 #define SSIF_IPMI_RESPONSE                      3
  66 #define SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE    9
  67
  68 /* ssif_debug is a bit-field
  69  *      SSIF_DEBUG_MSG -        commands and their responses
  70  *      SSIF_DEBUG_STATES -     message states
  71  *      SSIF_DEBUG_TIMING -      Measure times between events in the driver
  72  */
  73 #define SSIF_DEBUG_TIMING       4
  74 #define SSIF_DEBUG_STATE        2
  75 #define SSIF_DEBUG_MSG          1
  76 #define SSIF_NODEBUG            0
  77 #define SSIF_DEFAULT_DEBUG      (SSIF_NODEBUG)
  78
  79 /*
  80  * Timer values
  81  */
  82 #define SSIF_MSG_USEC           20000   /* 20ms between message tries. */
  83 #define SSIF_MSG_PART_USEC      5000    /* 5ms for a message part */
  84
  85 /* How many times to we retry sending/receiving the message. */
  86 #define SSIF_SEND_RETRIES       5
  87 #define SSIF_RECV_RETRIES       250
  88
  89 #define SSIF_MSG_MSEC           (SSIF_MSG_USEC / 1000)
  90 #define SSIF_MSG_JIFFIES        ((SSIF_MSG_USEC * 1000) / TICK_NSEC)
  91 #define SSIF_MSG_PART_JIFFIES   ((SSIF_MSG_PART_USEC * 1000) / TICK_NSEC)
  92
  93 enum ssif_intf_state {
  94         SSIF_NORMAL,
  95         SSIF_GETTING_FLAGS,
  96         SSIF_GETTING_EVENTS,
  97         SSIF_CLEARING_FLAGS,
  98         SSIF_GETTING_MESSAGES,
  99         /* FIXME - add watchdog stuff. */
 100 };
 101
 102 #define SSIF_IDLE(ssif)  ((ssif)->ssif_state == SSIF_NORMAL \
 103                           && (ssif)->curr_msg == NULL)
 104
 105 /*
 106  * Indexes into stats[] in ssif_info below.
 107  */
 108 enum ssif_stat_indexes {
 109         /* Number of total messages sent. */
 110         SSIF_STAT_sent_messages = 0,
 111
 112         /*
 113          * Number of message parts sent.  Messages may be broken into
 114          * parts if they are long.
 115          */
 116         SSIF_STAT_sent_messages_parts,
 117
 118         /*
 119          * Number of time a message was retried.
 120          */
 121         SSIF_STAT_send_retries,
 122
 123         /*
 124          * Number of times the send of a message failed.
 125          */
 126         SSIF_STAT_send_errors,
 127
 128         /*
 129          * Number of message responses received.
 130          */
 131         SSIF_STAT_received_messages,
 132
 133         /*
 134          * Number of message fragments received.
 135          */
 136         SSIF_STAT_received_message_parts,
 137
 138         /*
 139          * Number of times the receive of a message was retried.
 140          */
 141         SSIF_STAT_receive_retries,
 142
 143         /*
 144          * Number of errors receiving messages.
 145          */
 146         SSIF_STAT_receive_errors,
 147
 148         /*
 149          * Number of times a flag fetch was requested.
 150          */
 151         SSIF_STAT_flag_fetches,
 152
 153         /*
 154          * Number of times the hardware didn't follow the state machine.
 155          */
 156         SSIF_STAT_hosed,
 157
 158         /*
 159          * Number of received events.
 160          */
 161         SSIF_STAT_events,
 162
 163         /* Number of asyncronous messages received. */
 164         SSIF_STAT_incoming_messages,
 165
 166         /* Number of watchdog pretimeouts. */
 167         SSIF_STAT_watchdog_pretimeouts,
 168
 169         /* Number of alers received. */
 170         SSIF_STAT_alerts,
 171
 172         /* Always add statistics before this value, it must be last. */
 173         SSIF_NUM_STATS
 174 };
 175
 176 struct ssif_addr_info {
 177         unsigned short addr;
 178         struct i2c_board_info binfo;
 179         char *adapter_name;
 180         int debug;
 181         int slave_addr;
 182         enum ipmi_addr_src addr_src;
 183         union ipmi_smi_info_union addr_info;
 184
 185         struct mutex clients_mutex;
 186         struct list_head clients;
 187
 188         struct list_head link;
 189 };
 190
 191 struct ssif_info;
 192
 193 typedef void (*ssif_i2c_done)(struct ssif_info *ssif_info, int result,
 194                              unsigned char *data, unsigned int len);
 195
 196 struct ssif_info {
 197         ipmi_smi_t          intf;
 198         int                 intf_num;
 199         spinlock_t          lock;
 200         struct ipmi_smi_msg *waiting_msg;
 201         struct ipmi_smi_msg *curr_msg;
 202         enum ssif_intf_state ssif_state;
 203         unsigned long       ssif_debug;
 204
 205         struct ipmi_smi_handlers handlers;
 206
 207         enum ipmi_addr_src addr_source; /* ACPI, PCI, SMBIOS, hardcode, etc. */
 208         union ipmi_smi_info_union addr_info;
 209
 210         /*
 211          * Flags from the last GET_MSG_FLAGS command, used when an ATTN
 212          * is set to hold the flags until we are done handling everything
 213          * from the flags.
 214          */
 215 #define RECEIVE_MSG_AVAIL       0x01
 216 #define EVENT_MSG_BUFFER_FULL   0x02
 217 #define WDT_PRE_TIMEOUT_INT     0x08
 218         unsigned char       msg_flags;
 219
 220         u8                  global_enables;
 221         bool                has_event_buffer;
 222         bool                supports_alert;
 223
 224         /*
 225          * Used to tell what we should do with alerts.  If we are
 226          * waiting on a response, read the data immediately.
 227          */
 228         bool                got_alert;
 229         bool                waiting_alert;
 230
 231         /*
 232          * If set to true, this will request events the next time the
 233          * state machine is idle.
 234          */
 235         bool                req_events;
 236
 237         /*
 238          * If set to true, this will request flags the next time the
 239          * state machine is idle.
 240          */
 241         bool                req_flags;
 242
 243         /*
 244          * Used to perform timer operations when run-to-completion
 245          * mode is on.  This is a countdown timer.
 246          */
 247         int                 rtc_us_timer;
 248
 249         /* Used for sending/receiving data.  +1 for the length. */
 250         unsigned char data[IPMI_MAX_MSG_LENGTH + 1];
 251         unsigned int  data_len;
 252
 253         /* Temp receive buffer, gets copied into data. */
 254         unsigned char recv[I2C_SMBUS_BLOCK_MAX];
 255
 256         struct i2c_client *client;
 257         ssif_i2c_done done_handler;
 258
 259         /* Thread interface handling */
 260         struct task_struct *thread;
 261         struct completion wake_thread;
 262         bool stopping;
 263         int i2c_read_write;
 264         int i2c_command;
 265         unsigned char *i2c_data;
 266         unsigned int i2c_size;
 267
 268         /* From the device id response. */
 269         struct ipmi_device_id device_id;
 270
 271         struct timer_list retry_timer;
 272         int retries_left;
 273
 274         /* Info from SSIF cmd */
 275         unsigned char max_xmit_msg_size;
 276         unsigned char max_recv_msg_size;
 277         unsigned int  multi_support;
 278         int           supports_pec;
 279
 280 #define SSIF_NO_MULTI           0
 281 #define SSIF_MULTI_2_PART       1
 282 #define SSIF_MULTI_n_PART       2
 283         unsigned char *multi_data;
 284         unsigned int  multi_len;
 285         unsigned int  multi_pos;
 286
 287         atomic_t stats[SSIF_NUM_STATS];
 288 };
 289
 290 #define ssif_inc_stat(ssif, stat) \
 291         atomic_inc(&(ssif)->stats[SSIF_STAT_ ## stat])
 292 #define ssif_get_stat(ssif, stat) \
 293         ((unsigned int) atomic_read(&(ssif)->stats[SSIF_STAT_ ## stat]))
 294
 295 static bool initialized;
 296
 297 static atomic_t next_intf = ATOMIC_INIT(0);
 298
 299 static void return_hosed_msg(struct ssif_info *ssif_info,
 300                              struct ipmi_smi_msg *msg);
 301 static void start_next_msg(struct ssif_info *ssif_info, unsigned long *flags);
 302 static int start_send(struct ssif_info *ssif_info,
 303                       unsigned char   *data,
 304                       unsigned int    len);
 305
 306 static unsigned long *ipmi_ssif_lock_cond(struct ssif_info *ssif_info,
 307                                           unsigned long *flags)
 308 {
 309         spin_lock_irqsave(&ssif_info->lock, *flags);
 310         return flags;
 311 }
 312
 313 static void ipmi_ssif_unlock_cond(struct ssif_info *ssif_info,
 314                                   unsigned long *flags)
 315 {
 316         spin_unlock_irqrestore(&ssif_info->lock, *flags);
 317 }
 318
 319 static void deliver_recv_msg(struct ssif_info *ssif_info,
 320                              struct ipmi_smi_msg *msg)
 321 {
 322         ipmi_smi_t    intf = ssif_info->intf;
 323
 324         if (!intf) {
 325                 ipmi_free_smi_msg(msg);
 326         } else if (msg->rsp_size < 0) {
 327                 return_hosed_msg(ssif_info, msg);
 328                 pr_err(PFX
 329                        "Malformed message in deliver_recv_msg: rsp_size = %d\n",
 330                        msg->rsp_size);
 331         } else {
 332                 ipmi_smi_msg_received(intf, msg);
 333         }
 334 }
 335
 336 static void return_hosed_msg(struct ssif_info *ssif_info,
 337                              struct ipmi_smi_msg *msg)
 338 {
 339         ssif_inc_stat(ssif_info, hosed);
 340
 341         /* Make it a response */
 342         msg->rsp[0] = msg->data[0] | 4;
 343         msg->rsp[1] = msg->data[1];
 344         msg->rsp[2] = 0xFF; /* Unknown error. */
 345         msg->rsp_size = 3;
 346
 347         deliver_recv_msg(ssif_info, msg);
 348 }
 349
 350 /*
 351  * Must be called with the message lock held.  This will release the
 352  * message lock.  Note that the caller will check SSIF_IDLE and start a
 353  * new operation, so there is no need to check for new messages to
 354  * start in here.
 355  */
 356 static void start_clear_flags(struct ssif_info *ssif_info, unsigned long *flags)
 357 {
 358         unsigned char msg[3];
 359
 360         ssif_info->msg_flags &= ~WDT_PRE_TIMEOUT_INT;
 361         ssif_info->ssif_state = SSIF_CLEARING_FLAGS;
 362         ipmi_ssif_unlock_cond(ssif_info, flags);
 363
 364         /* Make sure the watchdog pre-timeout flag is not set at startup. */
 365         msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
 366         msg[1] = IPMI_CLEAR_MSG_FLAGS_CMD;
 367         msg[2] = WDT_PRE_TIMEOUT_INT;
 368
 369         if (start_send(ssif_info, msg, 3) != 0) {
 370                 /* Error, just go to normal state. */
 371                 ssif_info->ssif_state = SSIF_NORMAL;
 372         }
 373 }
 374
 375 static void start_flag_fetch(struct ssif_info *ssif_info, unsigned long *flags)
 376 {
 377         unsigned char mb[2];
 378
 379         ssif_info->req_flags = false;
 380         ssif_info->ssif_state = SSIF_GETTING_FLAGS;
 381         ipmi_ssif_unlock_cond(ssif_info, flags);
 382
 383         mb[0] = (IPMI_NETFN_APP_REQUEST << 2);
 384         mb[1] = IPMI_GET_MSG_FLAGS_CMD;
 385         if (start_send(ssif_info, mb, 2) != 0)
 386                 ssif_info->ssif_state = SSIF_NORMAL;
 387 }
 388
 389 static void check_start_send(struct ssif_info *ssif_info, unsigned long *flags,
 390                              struct ipmi_smi_msg *msg)
 391 {
 392         if (start_send(ssif_info, msg->data, msg->data_size) != 0) {
 393                 unsigned long oflags;
 394
 395                 flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
 396                 ssif_info->curr_msg = NULL;
 397                 ssif_info->ssif_state = SSIF_NORMAL;
 398                 ipmi_ssif_unlock_cond(ssif_info, flags);
 399                 ipmi_free_smi_msg(msg);
 400         }
 401 }
 402
 403 static void start_event_fetch(struct ssif_info *ssif_info, unsigned long *flags)
 404 {
 405         struct ipmi_smi_msg *msg;
 406
 407         ssif_info->req_events = false;
 408
 409         msg = ipmi_alloc_smi_msg();
 410         if (!msg) {
 411                 ssif_info->ssif_state = SSIF_NORMAL;
 412                 return;
 413         }
 414
 415         ssif_info->curr_msg = msg;
 416         ssif_info->ssif_state = SSIF_GETTING_EVENTS;
 417         ipmi_ssif_unlock_cond(ssif_info, flags);
 418
 419         msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
 420         msg->data[1] = IPMI_READ_EVENT_MSG_BUFFER_CMD;
 421         msg->data_size = 2;
 422
 423         check_start_send(ssif_info, flags, msg);
 424 }
 425
 426 static void start_recv_msg_fetch(struct ssif_info *ssif_info,
 427                                  unsigned long *flags)
 428 {
 429         struct ipmi_smi_msg *msg;
 430
 431         msg = ipmi_alloc_smi_msg();
 432         if (!msg) {
 433                 ssif_info->ssif_state = SSIF_NORMAL;
 434                 return;
 435         }
 436
 437         ssif_info->curr_msg = msg;
 438         ssif_info->ssif_state = SSIF_GETTING_MESSAGES;
 439         ipmi_ssif_unlock_cond(ssif_info, flags);
 440
 441         msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
 442         msg->data[1] = IPMI_GET_MSG_CMD;
 443         msg->data_size = 2;
 444
 445         check_start_send(ssif_info, flags, msg);
 446 }
 447
 448 /*
 449  * Must be called with the message lock held.  This will release the
 450  * message lock.  Note that the caller will check SSIF_IDLE and start a
 451  * new operation, so there is no need to check for new messages to
 452  * start in here.
 453  */
 454 static void handle_flags(struct ssif_info *ssif_info, unsigned long *flags)
 455 {
 456         if (ssif_info->msg_flags & WDT_PRE_TIMEOUT_INT) {
 457                 ipmi_smi_t intf = ssif_info->intf;
 458                 /* Watchdog pre-timeout */
 459                 ssif_inc_stat(ssif_info, watchdog_pretimeouts);
 460                 start_clear_flags(ssif_info, flags);
 461                 if (intf)
 462                         ipmi_smi_watchdog_pretimeout(intf);
 463         } else if (ssif_info->msg_flags & RECEIVE_MSG_AVAIL)
 464                 /* Messages available. */
 465                 start_recv_msg_fetch(ssif_info, flags);
 466         else if (ssif_info->msg_flags & EVENT_MSG_BUFFER_FULL)
 467                 /* Events available. */
 468                 start_event_fetch(ssif_info, flags);
 469         else {
 470                 ssif_info->ssif_state = SSIF_NORMAL;
 471                 ipmi_ssif_unlock_cond(ssif_info, flags);
 472         }
 473 }
 474
 475 static int ipmi_ssif_thread(void *data)
 476 {
 477         struct ssif_info *ssif_info = data;
 478
 479         while (!kthread_should_stop()) {
 480                 int result;
 481
 482                 /* Wait for something to do */
 483                 result = wait_for_completion_interruptible(
 484                                                 &ssif_info->wake_thread);
 485                 if (ssif_info->stopping)
 486                         break;
 487                 if (result == -ERESTARTSYS)
 488                         continue;
 489                 init_completion(&ssif_info->wake_thread);
 490
 491                 if (ssif_info->i2c_read_write == I2C_SMBUS_WRITE) {
 492                         result = i2c_smbus_write_block_data(
 493                                 ssif_info->client, ssif_info->i2c_command,
 494                                 ssif_info->i2c_data[0],
 495                                 ssif_info->i2c_data + 1);
 496                         ssif_info->done_handler(ssif_info, result, NULL, 0);
 497                 } else {
 498                         result = i2c_smbus_read_block_data(
 499                                 ssif_info->client, ssif_info->i2c_command,
 500                                 ssif_info->i2c_data);
 501                         if (result < 0)
 502                                 ssif_info->done_handler(ssif_info, result,
 503                                                         NULL, 0);
 504                         else
 505                                 ssif_info->done_handler(ssif_info, 0,
 506                                                         ssif_info->i2c_data,
 507                                                         result);
 508                 }
 509         }
 510
 511         return 0;
 512 }
 513
 514 static int ssif_i2c_send(struct ssif_info *ssif_info,
 515                         ssif_i2c_done handler,
 516                         int read_write, int command,
 517                         unsigned char *data, unsigned int size)
 518 {
 519         ssif_info->done_handler = handler;
 520
 521         ssif_info->i2c_read_write = read_write;
 522         ssif_info->i2c_command = command;
 523         ssif_info->i2c_data = data;
 524         ssif_info->i2c_size = size;
 525         complete(&ssif_info->wake_thread);
 526         return 0;
 527 }
 528
 529
 530 static void msg_done_handler(struct ssif_info *ssif_info, int result,
 531                              unsigned char *data, unsigned int len);
 532
 533 static void start_get(struct ssif_info *ssif_info)
 534 {
 535         int rv;
 536
 537         ssif_info->rtc_us_timer = 0;
 538         ssif_info->multi_pos = 0;
 539
 540         rv = ssif_i2c_send(ssif_info, msg_done_handler, I2C_SMBUS_READ,
 541                           SSIF_IPMI_RESPONSE,
 542                           ssif_info->recv, I2C_SMBUS_BLOCK_DATA);
 543         if (rv < 0) {
 544                 /* request failed, just return the error. */
 545                 if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
 546                         pr_info("Error from i2c_non_blocking_op(5)\n");
 547
 548                 msg_done_handler(ssif_info, -EIO, NULL, 0);
 549         }
 550 }
 551
 552 static void retry_timeout(unsigned long data)
 553 {
 554         struct ssif_info *ssif_info = (void *) data;
 555         unsigned long oflags, *flags;
 556         bool waiting;
 557
 558         if (ssif_info->stopping)
 559                 return;
 560
 561         flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
 562         waiting = ssif_info->waiting_alert;
 563         ssif_info->waiting_alert = false;
 564         ipmi_ssif_unlock_cond(ssif_info, flags);
 565
 566         if (waiting)
 567                 start_get(ssif_info);
 568 }
 569
 570
 571 static void ssif_alert(struct i2c_client *client, unsigned int data)
 572 {
 573         struct ssif_info *ssif_info = i2c_get_clientdata(client);
 574         unsigned long oflags, *flags;
 575         bool do_get = false;
 576
 577         ssif_inc_stat(ssif_info, alerts);
 578
 579         flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
 580         if (ssif_info->waiting_alert) {
 581                 ssif_info->waiting_alert = false;
 582                 del_timer(&ssif_info->retry_timer);
 583                 do_get = true;
 584         } else if (ssif_info->curr_msg) {
 585                 ssif_info->got_alert = true;
 586         }
 587         ipmi_ssif_unlock_cond(ssif_info, flags);
 588         if (do_get)
 589                 start_get(ssif_info);
 590 }
 591
 592 static int start_resend(struct ssif_info *ssif_info);
 593
 594 static void msg_done_handler(struct ssif_info *ssif_info, int result,
 595                              unsigned char *data, unsigned int len)
 596 {
 597         struct ipmi_smi_msg *msg;
 598         unsigned long oflags, *flags;
 599         int rv;
 600
 601         /*
 602          * We are single-threaded here, so no need for a lock until we
 603          * start messing with driver states or the queues.
 604          */
 605
 606         if (result < 0) {
 607                 ssif_info->retries_left--;
 608                 if (ssif_info->retries_left > 0) {
 609                         ssif_inc_stat(ssif_info, receive_retries);
 610
 611                         flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
 612                         ssif_info->waiting_alert = true;
 613                         ssif_info->rtc_us_timer = SSIF_MSG_USEC;
 614                         mod_timer(&ssif_info->retry_timer,
 615                                   jiffies + SSIF_MSG_JIFFIES);
 616                         ipmi_ssif_unlock_cond(ssif_info, flags);
 617                         return;
 618                 }
 619
 620                 ssif_inc_stat(ssif_info, receive_errors);
 621
 622                 if  (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
 623                         pr_info("Error in msg_done_handler: %d\n", result);
 624                 len = 0;
 625                 goto continue_op;
 626         }
 627
 628         if ((len > 1) && (ssif_info->multi_pos == 0)
 629                                 && (data[0] == 0x00) && (data[1] == 0x01)) {
 630                 /* Start of multi-part read.  Start the next transaction. */
 631                 int i;
 632
 633                 ssif_inc_stat(ssif_info, received_message_parts);
 634
 635                 /* Remove the multi-part read marker. */
 636                 len -= 2;
 637                 for (i = 0; i < len; i++)
 638                         ssif_info->data[i] = data[i+2];
 639                 ssif_info->multi_len = len;
 640                 ssif_info->multi_pos = 1;
 641
 642                 rv = ssif_i2c_send(ssif_info, msg_done_handler, I2C_SMBUS_READ,
 643                                   SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE,
 644                                   ssif_info->recv, I2C_SMBUS_BLOCK_DATA);
 645                 if (rv < 0) {
 646                         if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
 647                                 pr_info("Error from i2c_non_blocking_op(1)\n");
 648
 649                         result = -EIO;
 650                 } else
 651                         return;
 652         } else if (ssif_info->multi_pos) {
 653                 /* Middle of multi-part read.  Start the next transaction. */
 654                 int i;
 655                 unsigned char blocknum;
 656
 657                 if (len == 0) {
 658                         result = -EIO;
 659                         if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
 660                                 pr_info(PFX "Middle message with no data\n");
 661
 662                         goto continue_op;
 663                 }
 664
 665                 blocknum = data[0];
 666
 667                 if (ssif_info->multi_len + len - 1 > IPMI_MAX_MSG_LENGTH) {
 668                         /* Received message too big, abort the operation. */
 669                         result = -E2BIG;
 670                         if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
 671                                 pr_info("Received message too big\n");
 672
 673                         goto continue_op;
 674                 }
 675
 676                 /* Remove the blocknum from the data. */
 677                 len--;
 678                 for (i = 0; i < len; i++)
 679                         ssif_info->data[i + ssif_info->multi_len] = data[i + 1];
 680                 ssif_info->multi_len += len;
 681                 if (blocknum == 0xff) {
 682                         /* End of read */
 683                         len = ssif_info->multi_len;
 684                         data = ssif_info->data;
 685                 } else if (blocknum + 1 != ssif_info->multi_pos) {
 686                         /*
 687                          * Out of sequence block, just abort.  Block
 688                          * numbers start at zero for the second block,
 689                          * but multi_pos starts at one, so the +1.
 690                          */
 691                         result = -EIO;
 692                 } else {
 693                         ssif_inc_stat(ssif_info, received_message_parts);
 694
 695                         ssif_info->multi_pos++;
 696
 697                         rv = ssif_i2c_send(ssif_info, msg_done_handler,
 698                                            I2C_SMBUS_READ,
 699                                            SSIF_IPMI_MULTI_PART_RESPONSE_MIDDLE,
 700                                            ssif_info->recv,
 701                                            I2C_SMBUS_BLOCK_DATA);
 702                         if (rv < 0) {
 703                                 if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
 704                                         pr_info(PFX
 705                                                 "Error from ssif_i2c_send\n");
 706
 707                                 result = -EIO;
 708                         } else
 709                                 return;
 710                 }
 711         }
 712
 713         if (result < 0) {
 714                 ssif_inc_stat(ssif_info, receive_errors);
 715         } else {
 716                 ssif_inc_stat(ssif_info, received_messages);
 717                 ssif_inc_stat(ssif_info, received_message_parts);
 718         }
 719
 720
 721  continue_op:
 722         if (ssif_info->ssif_debug & SSIF_DEBUG_STATE)
 723                 pr_info(PFX "DONE 1: state = %d, result=%d.\n",
 724                         ssif_info->ssif_state, result);
 725
 726         flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
 727         msg = ssif_info->curr_msg;
 728         if (msg) {
 729                 msg->rsp_size = len;
 730                 if (msg->rsp_size > IPMI_MAX_MSG_LENGTH)
 731                         msg->rsp_size = IPMI_MAX_MSG_LENGTH;
 732                 memcpy(msg->rsp, data, msg->rsp_size);
 733                 ssif_info->curr_msg = NULL;
 734         }
 735
 736         switch (ssif_info->ssif_state) {
 737         case SSIF_NORMAL:
 738                 ipmi_ssif_unlock_cond(ssif_info, flags);
 739                 if (!msg)
 740                         break;
 741
 742                 if (result < 0)
 743                         return_hosed_msg(ssif_info, msg);
 744                 else
 745                         deliver_recv_msg(ssif_info, msg);
 746                 break;
 747
 748         case SSIF_GETTING_FLAGS:
 749                 /* We got the flags from the SSIF, now handle them. */
 750                 if ((result < 0) || (len < 4) || (data[2] != 0)) {
 751                         /*
 752                          * Error fetching flags, or invalid length,
 753                          * just give up for now.
 754                          */
 755                         ssif_info->ssif_state = SSIF_NORMAL;
 756                         ipmi_ssif_unlock_cond(ssif_info, flags);
 757                         pr_warn(PFX "Error getting flags: %d %d, %x\n",
 758                                result, len, data[2]);
 759                 } else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
 760                            || data[1] != IPMI_GET_MSG_FLAGS_CMD) {
 761                         pr_warn(PFX "Invalid response getting flags: %x %x\n",
 762                                 data[0], data[1]);
 763                 } else {
 764                         ssif_inc_stat(ssif_info, flag_fetches);
 765                         ssif_info->msg_flags = data[3];
 766                         handle_flags(ssif_info, flags);
 767                 }
 768                 break;
 769
 770         case SSIF_CLEARING_FLAGS:
 771                 /* We cleared the flags. */
 772                 if ((result < 0) || (len < 3) || (data[2] != 0)) {
 773                         /* Error clearing flags */
 774                         pr_warn(PFX "Error clearing flags: %d %d, %x\n",
 775                                result, len, data[2]);
 776                 } else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
 777                            || data[1] != IPMI_CLEAR_MSG_FLAGS_CMD) {
 778                         pr_warn(PFX "Invalid response clearing flags: %x %x\n",
 779                                 data[0], data[1]);
 780                 }
 781                 ssif_info->ssif_state = SSIF_NORMAL;
 782                 ipmi_ssif_unlock_cond(ssif_info, flags);
 783                 break;
 784
 785         case SSIF_GETTING_EVENTS:
 786                 if ((result < 0) || (len < 3) || (msg->rsp[2] != 0)) {
 787                         /* Error getting event, probably done. */
 788                         msg->done(msg);
 789
 790                         /* Take off the event flag. */
 791                         ssif_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
 792                         handle_flags(ssif_info, flags);
 793                 } else if (msg->rsp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
 794                            || msg->rsp[1] != IPMI_READ_EVENT_MSG_BUFFER_CMD) {
 795                         pr_warn(PFX "Invalid response getting events: %x %x\n",
 796                                 msg->rsp[0], msg->rsp[1]);
 797                         msg->done(msg);
 798                         /* Take off the event flag. */
 799                         ssif_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
 800                         handle_flags(ssif_info, flags);
 801                 } else {
 802                         handle_flags(ssif_info, flags);
 803                         ssif_inc_stat(ssif_info, events);
 804                         deliver_recv_msg(ssif_info, msg);
 805                 }
 806                 break;
 807
 808         case SSIF_GETTING_MESSAGES:
 809                 if ((result < 0) || (len < 3) || (msg->rsp[2] != 0)) {
 810                         /* Error getting event, probably done. */
 811                         msg->done(msg);
 812
 813                         /* Take off the msg flag. */
 814                         ssif_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
 815                         handle_flags(ssif_info, flags);
 816                 } else if (msg->rsp[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2
 817                            || msg->rsp[1] != IPMI_GET_MSG_CMD) {
 818                         pr_warn(PFX "Invalid response clearing flags: %x %x\n",
 819                                 msg->rsp[0], msg->rsp[1]);
 820                         msg->done(msg);
 821
 822                         /* Take off the msg flag. */
 823                         ssif_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
 824                         handle_flags(ssif_info, flags);
 825                 } else {
 826                         ssif_inc_stat(ssif_info, incoming_messages);
 827                         handle_flags(ssif_info, flags);
 828                         deliver_recv_msg(ssif_info, msg);
 829                 }
 830                 break;
 831         }
 832
 833         flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
 834         if (SSIF_IDLE(ssif_info) && !ssif_info->stopping) {
 835                 if (ssif_info->req_events)
 836                         start_event_fetch(ssif_info, flags);
 837                 else if (ssif_info->req_flags)
 838                         start_flag_fetch(ssif_info, flags);
 839                 else
 840                         start_next_msg(ssif_info, flags);
 841         } else
 842                 ipmi_ssif_unlock_cond(ssif_info, flags);
 843
 844         if (ssif_info->ssif_debug & SSIF_DEBUG_STATE)
 845                 pr_info(PFX "DONE 2: state = %d.\n", ssif_info->ssif_state);
 846 }
 847
 848 static void msg_written_handler(struct ssif_info *ssif_info, int result,
 849                                 unsigned char *data, unsigned int len)
 850 {
 851         int rv;
 852
 853         /* We are single-threaded here, so no need for a lock. */
 854         if (result < 0) {
 855                 ssif_info->retries_left--;
 856                 if (ssif_info->retries_left > 0) {
 857                         if (!start_resend(ssif_info)) {
 858                                 ssif_inc_stat(ssif_info, send_retries);
 859                                 return;
 860                         }
 861                         /* request failed, just return the error. */
 862                         ssif_inc_stat(ssif_info, send_errors);
 863
 864                         if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
 865                                 pr_info(PFX
 866                                         "Out of retries in msg_written_handler\n");
 867                         msg_done_handler(ssif_info, -EIO, NULL, 0);
 868                         return;
 869                 }
 870
 871                 ssif_inc_stat(ssif_info, send_errors);
 872
 873                 /*
 874                  * Got an error on transmit, let the done routine
 875                  * handle it.
 876                  */
 877                 if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
 878                         pr_info("Error in msg_written_handler: %d\n", result);
 879
 880                 msg_done_handler(ssif_info, result, NULL, 0);
 881                 return;
 882         }
 883
 884         if (ssif_info->multi_data) {
 885                 /*
 886                  * In the middle of a multi-data write.  See the comment
 887                  * in the SSIF_MULTI_n_PART case in the probe function
 888                  * for details on the intricacies of this.
 889                  */
 890                 int left;
 891
 892                 ssif_inc_stat(ssif_info, sent_messages_parts);
 893
 894                 left = ssif_info->multi_len - ssif_info->multi_pos;
 895                 if (left > 32)
 896                         left = 32;
 897                 /* Length byte. */
 898                 ssif_info->multi_data[ssif_info->multi_pos] = left;
 899                 ssif_info->multi_pos += left;
 900                 if (left < 32)
 901                         /*
 902                          * Write is finished.  Note that we must end
 903                          * with a write of less than 32 bytes to
 904                          * complete the transaction, even if it is
 905                          * zero bytes.
 906                          */
 907                         ssif_info->multi_data = NULL;
 908
 909                 rv = ssif_i2c_send(ssif_info, msg_written_handler,
 910                                   I2C_SMBUS_WRITE,
 911                                   SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE,
 912                                   ssif_info->multi_data + ssif_info->multi_pos,
 913                                   I2C_SMBUS_BLOCK_DATA);
 914                 if (rv < 0) {
 915                         /* request failed, just return the error. */
 916                         ssif_inc_stat(ssif_info, send_errors);
 917
 918                         if (ssif_info->ssif_debug & SSIF_DEBUG_MSG)
 919                                 pr_info("Error from i2c_non_blocking_op(3)\n");
 920                         msg_done_handler(ssif_info, -EIO, NULL, 0);
 921                 }
 922         } else {
 923                 unsigned long oflags, *flags;
 924                 bool got_alert;
 925
 926                 ssif_inc_stat(ssif_info, sent_messages);
 927                 ssif_inc_stat(ssif_info, sent_messages_parts);
 928
 929                 flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
 930                 got_alert = ssif_info->got_alert;
 931                 if (got_alert) {
 932                         ssif_info->got_alert = false;
 933                         ssif_info->waiting_alert = false;
 934                 }
 935
 936                 if (got_alert) {
 937                         ipmi_ssif_unlock_cond(ssif_info, flags);
 938                         /* The alert already happened, try now. */
 939                         retry_timeout((unsigned long) ssif_info);
 940                 } else {
 941                         /* Wait a jiffie then request the next message */
 942                         ssif_info->waiting_alert = true;
 943                         ssif_info->retries_left = SSIF_RECV_RETRIES;
 944                         ssif_info->rtc_us_timer = SSIF_MSG_PART_USEC;
 945                         mod_timer(&ssif_info->retry_timer,
 946                                   jiffies + SSIF_MSG_PART_JIFFIES);
 947                         ipmi_ssif_unlock_cond(ssif_info, flags);
 948                 }
 949         }
 950 }
 951
 952 static int start_resend(struct ssif_info *ssif_info)
 953 {
 954         int rv;
 955         int command;
 956
 957         ssif_info->got_alert = false;
 958
 959         if (ssif_info->data_len > 32) {
 960                 command = SSIF_IPMI_MULTI_PART_REQUEST_START;
 961                 ssif_info->multi_data = ssif_info->data;
 962                 ssif_info->multi_len = ssif_info->data_len;
 963                 /*
 964                  * Subtle thing, this is 32, not 33, because we will
 965                  * overwrite the thing at position 32 (which was just
 966                  * transmitted) with the new length.
 967                  */
 968                 ssif_info->multi_pos = 32;
 969                 ssif_info->data[0] = 32;
 970         } else {
 971                 ssif_info->multi_data = NULL;
 972                 command = SSIF_IPMI_REQUEST;
 973                 ssif_info->data[0] = ssif_info->data_len;
 974         }
 975
 976         rv = ssif_i2c_send(ssif_info, msg_written_handler, I2C_SMBUS_WRITE,
 977                           command, ssif_info->data, I2C_SMBUS_BLOCK_DATA);
 978         if (rv && (ssif_info->ssif_debug & SSIF_DEBUG_MSG))
 979                 pr_info("Error from i2c_non_blocking_op(4)\n");
 980         return rv;
 981 }
 982
 983 static int start_send(struct ssif_info *ssif_info,
 984                       unsigned char   *data,
 985                       unsigned int    len)
 986 {
 987         if (len > IPMI_MAX_MSG_LENGTH)
 988                 return -E2BIG;
 989         if (len > ssif_info->max_xmit_msg_size)
 990                 return -E2BIG;
 991
 992         ssif_info->retries_left = SSIF_SEND_RETRIES;
 993         memcpy(ssif_info->data + 1, data, len);
 994         ssif_info->data_len = len;
 995         return start_resend(ssif_info);
 996 }
 997
 998 /* Must be called with the message lock held. */
 999 static void start_next_msg(struct ssif_info *ssif_info, unsigned long *flags)
1000 {
1001         struct ipmi_smi_msg *msg;
1002         unsigned long oflags;
1003
1004  restart:
1005         if (!SSIF_IDLE(ssif_info)) {
1006                 ipmi_ssif_unlock_cond(ssif_info, flags);
1007                 return;
1008         }
1009
1010         if (!ssif_info->waiting_msg) {
1011                 ssif_info->curr_msg = NULL;
1012                 ipmi_ssif_unlock_cond(ssif_info, flags);
1013         } else {
1014                 int rv;
1015
1016                 ssif_info->curr_msg = ssif_info->waiting_msg;
1017                 ssif_info->waiting_msg = NULL;
1018                 ipmi_ssif_unlock_cond(ssif_info, flags);
1019                 rv = start_send(ssif_info,
1020                                 ssif_info->curr_msg->data,
1021                                 ssif_info->curr_msg->data_size);
1022                 if (rv) {
1023                         msg = ssif_info->curr_msg;
1024                         ssif_info->curr_msg = NULL;
1025                         return_hosed_msg(ssif_info, msg);
1026                         flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
1027                         goto restart;
1028                 }
1029         }
1030 }
1031
1032 static void sender(void                *send_info,
1033                    struct ipmi_smi_msg *msg)
1034 {
1035         struct ssif_info *ssif_info = (struct ssif_info *) send_info;
1036         unsigned long oflags, *flags;
1037
1038         BUG_ON(ssif_info->waiting_msg);
1039         ssif_info->waiting_msg = msg;
1040
1041         flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
1042         start_next_msg(ssif_info, flags);
1043
1044         if (ssif_info->ssif_debug & SSIF_DEBUG_TIMING) {
1045                 struct timespec64 t;
1046
1047                 ktime_get_real_ts64(&t);
1048                 pr_info("**Enqueue %02x %02x: %lld.%6.6ld\n",
1049                        msg->data[0], msg->data[1],
1050                        (long long) t.tv_sec, (long) t.tv_nsec / NSEC_PER_USEC);
1051         }
1052 }
1053
1054 static int get_smi_info(void *send_info, struct ipmi_smi_info *data)
1055 {
1056         struct ssif_info *ssif_info = send_info;
1057
1058         data->addr_src = ssif_info->addr_source;
1059         data->dev = &ssif_info->client->dev;
1060         data->addr_info = ssif_info->addr_info;
1061         get_device(data->dev);
1062
1063         return 0;
1064 }
1065
1066 /*
1067  * Instead of having our own timer to periodically check the message
1068  * flags, we let the message handler drive us.
1069  */
1070 static void request_events(void *send_info)
1071 {
1072         struct ssif_info *ssif_info = (struct ssif_info *) send_info;
1073         unsigned long oflags, *flags;
1074
1075         if (!ssif_info->has_event_buffer)
1076                 return;
1077
1078         flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
1079         /*
1080          * Request flags first, not events, because the lower layer
1081          * doesn't have a way to send an attention.  But make sure
1082          * event checking still happens.
1083          */
1084         ssif_info->req_events = true;
1085         if (SSIF_IDLE(ssif_info))
1086                 start_flag_fetch(ssif_info, flags);
1087         else {
1088                 ssif_info->req_flags = true;
1089                 ipmi_ssif_unlock_cond(ssif_info, flags);
1090         }
1091 }
1092
1093 static int inc_usecount(void *send_info)
1094 {
1095         struct ssif_info *ssif_info = send_info;
1096
1097         if (!i2c_get_adapter(ssif_info->client->adapter->nr))
1098                 return -ENODEV;
1099
1100         i2c_use_client(ssif_info->client);
1101         return 0;
1102 }
1103
1104 static void dec_usecount(void *send_info)
1105 {
1106         struct ssif_info *ssif_info = send_info;
1107
1108         i2c_release_client(ssif_info->client);
1109         i2c_put_adapter(ssif_info->client->adapter);
1110 }
1111
1112 static int ssif_start_processing(void *send_info,
1113                                  ipmi_smi_t intf)
1114 {
1115         struct ssif_info *ssif_info = send_info;
1116
1117         ssif_info->intf = intf;
1118
1119         return 0;
1120 }
1121
1122 #define MAX_SSIF_BMCS 4
1123
1124 static unsigned short addr[MAX_SSIF_BMCS];
1125 static int num_addrs;
1126 module_param_array(addr, ushort, &num_addrs, 0);
1127 MODULE_PARM_DESC(addr, "The addresses to scan for IPMI BMCs on the SSIFs.");
1128
1129 static char *adapter_name[MAX_SSIF_BMCS];
1130 static int num_adapter_names;
1131 module_param_array(adapter_name, charp, &num_adapter_names, 0);
1132 MODULE_PARM_DESC(adapter_name, "The string name of the I2C device that has the BMC.  By default all devices are scanned.");
1133
1134 static int slave_addrs[MAX_SSIF_BMCS];
1135 static int num_slave_addrs;
1136 module_param_array(slave_addrs, int, &num_slave_addrs, 0);
1137 MODULE_PARM_DESC(slave_addrs,
1138                  "The default IPMB slave address for the controller.");
1139
1140 static bool alerts_broken;
1141 module_param(alerts_broken, bool, 0);
1142 MODULE_PARM_DESC(alerts_broken, "Don't enable alerts for the controller.");
1143
1144 /*
1145  * Bit 0 enables message debugging, bit 1 enables state debugging, and
1146  * bit 2 enables timing debugging.  This is an array indexed by
1147  * interface number"
1148  */
1149 static int dbg[MAX_SSIF_BMCS];
1150 static int num_dbg;
1151 module_param_array(dbg, int, &num_dbg, 0);
1152 MODULE_PARM_DESC(dbg, "Turn on debugging.");
1153
1154 static bool ssif_dbg_probe;
1155 module_param_named(dbg_probe, ssif_dbg_probe, bool, 0);
1156 MODULE_PARM_DESC(dbg_probe, "Enable debugging of probing of adapters.");
1157
1158 static int use_thread;
1159 module_param(use_thread, int, 0);
1160 MODULE_PARM_DESC(use_thread, "Use the thread interface.");
1161
1162 static bool ssif_tryacpi = true;
1163 module_param_named(tryacpi, ssif_tryacpi, bool, 0);
1164 MODULE_PARM_DESC(tryacpi, "Setting this to zero will disable the default scan of the interfaces identified via ACPI");
1165
1166 static bool ssif_trydmi = true;
1167 module_param_named(trydmi, ssif_trydmi, bool, 0);
1168 MODULE_PARM_DESC(trydmi, "Setting this to zero will disable the default scan of the interfaces identified via DMI (SMBIOS)");
1169
1170 static DEFINE_MUTEX(ssif_infos_mutex);
1171 static LIST_HEAD(ssif_infos);
1172
1173 static int ssif_remove(struct i2c_client *client)
1174 {
1175         struct ssif_info *ssif_info = i2c_get_clientdata(client);
1176         int rv;
1177
1178         if (!ssif_info)
1179                 return 0;
1180
1181         /*
1182          * After this point, we won't deliver anything asychronously
1183          * to the message handler.  We can unregister ourself.
1184          */
1185         rv = ipmi_unregister_smi(ssif_info->intf);
1186         if (rv) {
1187                 pr_err(PFX "Unable to unregister device: errno=%d\n", rv);
1188                 return rv;
1189         }
1190         ssif_info->intf = NULL;
1191
1192         /* make sure the driver is not looking for flags any more. */
1193         while (ssif_info->ssif_state != SSIF_NORMAL)
1194                 schedule_timeout(1);
1195
1196         ssif_info->stopping = true;
1197         del_timer_sync(&ssif_info->retry_timer);
1198         if (ssif_info->thread) {
1199                 complete(&ssif_info->wake_thread);
1200                 kthread_stop(ssif_info->thread);
1201         }
1202
1203         /*
1204          * No message can be outstanding now, we have removed the
1205          * upper layer and it permitted us to do so.
1206          */
1207         kfree(ssif_info);
1208         return 0;
1209 }
1210
1211 static int do_cmd(struct i2c_client *client, int len, unsigned char *msg,
1212                   int *resp_len, unsigned char *resp)
1213 {
1214         int retry_cnt;
1215         int ret;
1216
1217         retry_cnt = SSIF_SEND_RETRIES;
1218  retry1:
1219         ret = i2c_smbus_write_block_data(client, SSIF_IPMI_REQUEST, len, msg);
1220         if (ret) {
1221                 retry_cnt--;
1222                 if (retry_cnt > 0)
1223                         goto retry1;
1224                 return -ENODEV;
1225         }
1226
1227         ret = -ENODEV;
1228         retry_cnt = SSIF_RECV_RETRIES;
1229         while (retry_cnt > 0) {
1230                 ret = i2c_smbus_read_block_data(client, SSIF_IPMI_RESPONSE,
1231                                                 resp);
1232                 if (ret > 0)
1233                         break;
1234                 msleep(SSIF_MSG_MSEC);
1235                 retry_cnt--;
1236                 if (retry_cnt <= 0)
1237                         break;
1238         }
1239
1240         if (ret > 0) {
1241                 /* Validate that the response is correct. */
1242                 if (ret < 3 ||
1243                     (resp[0] != (msg[0] | (1 << 2))) ||
1244                     (resp[1] != msg[1]))
1245                         ret = -EINVAL;
1246                 else {
1247                         *resp_len = ret;
1248                         ret = 0;
1249                 }
1250         }
1251
1252         return ret;
1253 }
1254
1255 static int ssif_detect(struct i2c_client *client, struct i2c_board_info *info)
1256 {
1257         unsigned char *resp;
1258         unsigned char msg[3];
1259         int           rv;
1260         int           len;
1261
1262         resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
1263         if (!resp)
1264                 return -ENOMEM;
1265
1266         /* Do a Get Device ID command, since it is required. */
1267         msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1268         msg[1] = IPMI_GET_DEVICE_ID_CMD;
1269         rv = do_cmd(client, 2, msg, &len, resp);
1270         if (rv)
1271                 rv = -ENODEV;
1272         else
1273                 strlcpy(info->type, DEVICE_NAME, I2C_NAME_SIZE);
1274         kfree(resp);
1275         return rv;
1276 }
1277
1278 static int smi_type_proc_show(struct seq_file *m, void *v)
1279 {
1280         seq_puts(m, "ssif\n");
1281
1282         return 0;
1283 }
1284
1285 static int smi_type_proc_open(struct inode *inode, struct file *file)
1286 {
1287         return single_open(file, smi_type_proc_show, inode->i_private);
1288 }
1289
1290 static const struct file_operations smi_type_proc_ops = {
1291         .open           = smi_type_proc_open,
1292         .read           = seq_read,
1293         .llseek         = seq_lseek,
1294         .release        = single_release,
1295 };
1296
1297 static int smi_stats_proc_show(struct seq_file *m, void *v)
1298 {
1299         struct ssif_info *ssif_info = m->private;
1300
1301         seq_printf(m, "sent_messages:          %u\n",
1302                    ssif_get_stat(ssif_info, sent_messages));
1303         seq_printf(m, "sent_messages_parts:    %u\n",
1304                    ssif_get_stat(ssif_info, sent_messages_parts));
1305         seq_printf(m, "send_retries:           %u\n",
1306                    ssif_get_stat(ssif_info, send_retries));
1307         seq_printf(m, "send_errors:            %u\n",
1308                    ssif_get_stat(ssif_info, send_errors));
1309         seq_printf(m, "received_messages:      %u\n",
1310                    ssif_get_stat(ssif_info, received_messages));
1311         seq_printf(m, "received_message_parts: %u\n",
1312                    ssif_get_stat(ssif_info, received_message_parts));
1313         seq_printf(m, "receive_retries:        %u\n",
1314                    ssif_get_stat(ssif_info, receive_retries));
1315         seq_printf(m, "receive_errors:         %u\n",
1316                    ssif_get_stat(ssif_info, receive_errors));
1317         seq_printf(m, "flag_fetches:           %u\n",
1318                    ssif_get_stat(ssif_info, flag_fetches));
1319         seq_printf(m, "hosed:                  %u\n",
1320                    ssif_get_stat(ssif_info, hosed));
1321         seq_printf(m, "events:                 %u\n",
1322                    ssif_get_stat(ssif_info, events));
1323         seq_printf(m, "watchdog_pretimeouts:   %u\n",
1324                    ssif_get_stat(ssif_info, watchdog_pretimeouts));
1325         seq_printf(m, "alerts:                 %u\n",
1326                    ssif_get_stat(ssif_info, alerts));
1327         return 0;
1328 }
1329
1330 static int smi_stats_proc_open(struct inode *inode, struct file *file)
1331 {
1332         return single_open(file, smi_stats_proc_show, PDE_DATA(inode));
1333 }
1334
1335 static const struct file_operations smi_stats_proc_ops = {
1336         .open           = smi_stats_proc_open,
1337         .read           = seq_read,
1338         .llseek         = seq_lseek,
1339         .release        = single_release,
1340 };
1341
1342 static int strcmp_nospace(char *s1, char *s2)
1343 {
1344         while (*s1 && *s2) {
1345                 while (isspace(*s1))
1346                         s1++;
1347                 while (isspace(*s2))
1348                         s2++;
1349                 if (*s1 > *s2)
1350                         return 1;
1351                 if (*s1 < *s2)
1352                         return -1;
1353                 s1++;
1354                 s2++;
1355         }
1356         return 0;
1357 }
1358
1359 static struct ssif_addr_info *ssif_info_find(unsigned short addr,
1360                                              char *adapter_name,
1361                                              bool match_null_name)
1362 {
1363         struct ssif_addr_info *info, *found = NULL;
1364
1365 restart:
1366         list_for_each_entry(info, &ssif_infos, link) {
1367                 if (info->binfo.addr == addr) {
1368                         if (info->adapter_name || adapter_name) {
1369                                 if (!info->adapter_name != !adapter_name) {
1370                                         /* One is NULL and one is not */
1371                                         continue;
1372                                 }
1373                                 if (adapter_name &&
1374                                     strcmp_nospace(info->adapter_name,
1375                                                    adapter_name))
1376                                         /* Names do not match */
1377                                         continue;
1378                         }
1379                         found = info;
1380                         break;
1381                 }
1382         }
1383
1384         if (!found && match_null_name) {
1385                 /* Try to get an exact match first, then try with a NULL name */
1386                 adapter_name = NULL;
1387                 match_null_name = false;
1388                 goto restart;
1389         }
1390
1391         return found;
1392 }
1393
1394 static bool check_acpi(struct ssif_info *ssif_info, struct device *dev)
1395 {
1396 #ifdef CONFIG_ACPI
1397         acpi_handle acpi_handle;
1398
1399         acpi_handle = ACPI_HANDLE(dev);
1400         if (acpi_handle) {
1401                 ssif_info->addr_source = SI_ACPI;
1402                 ssif_info->addr_info.acpi_info.acpi_handle = acpi_handle;
1403                 return true;
1404         }
1405 #endif
1406         return false;
1407 }
1408
1409 /*
1410  * Global enables we care about.
1411  */
1412 #define GLOBAL_ENABLES_MASK (IPMI_BMC_EVT_MSG_BUFF | IPMI_BMC_RCV_MSG_INTR | \
1413                              IPMI_BMC_EVT_MSG_INTR)
1414
1415 static int ssif_probe(struct i2c_client *client, const struct i2c_device_id *id)
1416 {
1417         unsigned char     msg[3];
1418         unsigned char     *resp;
1419         struct ssif_info   *ssif_info;
1420         int               rv = 0;
1421         int               len;
1422         int               i;
1423         u8                slave_addr = 0;
1424         struct ssif_addr_info *addr_info = NULL;
1425
1426
1427         resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
1428         if (!resp)
1429                 return -ENOMEM;
1430
1431         ssif_info = kzalloc(sizeof(*ssif_info), GFP_KERNEL);
1432         if (!ssif_info) {
1433                 kfree(resp);
1434                 return -ENOMEM;
1435         }
1436
1437         if (!check_acpi(ssif_info, &client->dev)) {
1438                 addr_info = ssif_info_find(client->addr, client->adapter->name,
1439                                            true);
1440                 if (!addr_info) {
1441                         /* Must have come in through sysfs. */
1442                         ssif_info->addr_source = SI_HOTMOD;
1443                 } else {
1444                         ssif_info->addr_source = addr_info->addr_src;
1445                         ssif_info->ssif_debug = addr_info->debug;
1446                         ssif_info->addr_info = addr_info->addr_info;
1447                         slave_addr = addr_info->slave_addr;
1448                 }
1449         }
1450
1451         pr_info(PFX "Trying %s-specified SSIF interface at i2c address 0x%x, adapter %s, slave address 0x%x\n",
1452                ipmi_addr_src_to_str(ssif_info->addr_source),
1453                client->addr, client->adapter->name, slave_addr);
1454
1455         /*
1456          * Do a Get Device ID command, since it comes back with some
1457          * useful info.
1458          */
1459         msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1460         msg[1] = IPMI_GET_DEVICE_ID_CMD;
1461         rv = do_cmd(client, 2, msg, &len, resp);
1462         if (rv)
1463                 goto out;
1464
1465         rv = ipmi_demangle_device_id(resp, len, &ssif_info->device_id);
1466         if (rv)
1467                 goto out;
1468
1469         ssif_info->client = client;
1470         i2c_set_clientdata(client, ssif_info);
1471
1472         /* Now check for system interface capabilities */
1473         msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1474         msg[1] = IPMI_GET_SYSTEM_INTERFACE_CAPABILITIES_CMD;
1475         msg[2] = 0; /* SSIF */
1476         rv = do_cmd(client, 3, msg, &len, resp);
1477         if (!rv && (len >= 3) && (resp[2] == 0)) {
1478                 if (len < 7) {
1479                         if (ssif_dbg_probe)
1480                                 pr_info(PFX "SSIF info too short: %d\n", len);
1481                         goto no_support;
1482                 }
1483
1484                 /* Got a good SSIF response, handle it. */
1485                 ssif_info->max_xmit_msg_size = resp[5];
1486                 ssif_info->max_recv_msg_size = resp[6];
1487                 ssif_info->multi_support = (resp[4] >> 6) & 0x3;
1488                 ssif_info->supports_pec = (resp[4] >> 3) & 0x1;
1489
1490                 /* Sanitize the data */
1491                 switch (ssif_info->multi_support) {
1492                 case SSIF_NO_MULTI:
1493                         if (ssif_info->max_xmit_msg_size > 32)
1494                                 ssif_info->max_xmit_msg_size = 32;
1495                         if (ssif_info->max_recv_msg_size > 32)
1496                                 ssif_info->max_recv_msg_size = 32;
1497                         break;
1498
1499                 case SSIF_MULTI_2_PART:
1500                         if (ssif_info->max_xmit_msg_size > 63)
1501                                 ssif_info->max_xmit_msg_size = 63;
1502                         if (ssif_info->max_recv_msg_size > 62)
1503                                 ssif_info->max_recv_msg_size = 62;
1504                         break;
1505
1506                 case SSIF_MULTI_n_PART:
1507                         /*
1508                          * The specification is rather confusing at
1509                          * this point, but I think I understand what
1510                          * is meant.  At least I have a workable
1511                          * solution.  With multi-part messages, you
1512                          * cannot send a message that is a multiple of
1513                          * 32-bytes in length, because the start and
1514                          * middle messages are 32-bytes and the end
1515                          * message must be at least one byte.  You
1516                          * can't fudge on an extra byte, that would
1517                          * screw up things like fru data writes.  So
1518                          * we limit the length to 63 bytes.  That way
1519                          * a 32-byte message gets sent as a single
1520                          * part.  A larger message will be a 32-byte
1521                          * start and the next message is always going
1522                          * to be 1-31 bytes in length.  Not ideal, but
1523                          * it should work.
1524                          */
1525                         if (ssif_info->max_xmit_msg_size > 63)
1526                                 ssif_info->max_xmit_msg_size = 63;
1527                         break;
1528
1529                 default:
1530                         /* Data is not sane, just give up. */
1531                         goto no_support;
1532                 }
1533         } else {
1534  no_support:
1535                 /* Assume no multi-part or PEC support */
1536                 pr_info(PFX "Error fetching SSIF: %d %d %2.2x, your system probably doesn't support this command so using defaults\n",
1537                        rv, len, resp[2]);
1538
1539                 ssif_info->max_xmit_msg_size = 32;
1540                 ssif_info->max_recv_msg_size = 32;
1541                 ssif_info->multi_support = SSIF_NO_MULTI;
1542                 ssif_info->supports_pec = 0;
1543         }
1544
1545         /* Make sure the NMI timeout is cleared. */
1546         msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1547         msg[1] = IPMI_CLEAR_MSG_FLAGS_CMD;
1548         msg[2] = WDT_PRE_TIMEOUT_INT;
1549         rv = do_cmd(client, 3, msg, &len, resp);
1550         if (rv || (len < 3) || (resp[2] != 0))
1551                 pr_warn(PFX "Unable to clear message flags: %d %d %2.2x\n",
1552                         rv, len, resp[2]);
1553
1554         /* Attempt to enable the event buffer. */
1555         msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1556         msg[1] = IPMI_GET_BMC_GLOBAL_ENABLES_CMD;
1557         rv = do_cmd(client, 2, msg, &len, resp);
1558         if (rv || (len < 4) || (resp[2] != 0)) {
1559                 pr_warn(PFX "Error getting global enables: %d %d %2.2x\n",
1560                         rv, len, resp[2]);
1561                 rv = 0; /* Not fatal */
1562                 goto found;
1563         }
1564
1565         ssif_info->global_enables = resp[3];
1566
1567         if (resp[3] & IPMI_BMC_EVT_MSG_BUFF) {
1568                 ssif_info->has_event_buffer = true;
1569                 /* buffer is already enabled, nothing to do. */
1570                 goto found;
1571         }
1572
1573         msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1574         msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
1575         msg[2] = ssif_info->global_enables | IPMI_BMC_EVT_MSG_BUFF;
1576         rv = do_cmd(client, 3, msg, &len, resp);
1577         if (rv || (len < 2)) {
1578                 pr_warn(PFX "Error setting global enables: %d %d %2.2x\n",
1579                         rv, len, resp[2]);
1580                 rv = 0; /* Not fatal */
1581                 goto found;
1582         }
1583
1584         if (resp[2] == 0) {
1585                 /* A successful return means the event buffer is supported. */
1586                 ssif_info->has_event_buffer = true;
1587                 ssif_info->global_enables |= IPMI_BMC_EVT_MSG_BUFF;
1588         }
1589
1590         /* Some systems don't behave well if you enable alerts. */
1591         if (alerts_broken)
1592                 goto found;
1593
1594         msg[0] = IPMI_NETFN_APP_REQUEST << 2;
1595         msg[1] = IPMI_SET_BMC_GLOBAL_ENABLES_CMD;
1596         msg[2] = ssif_info->global_enables | IPMI_BMC_RCV_MSG_INTR;
1597         rv = do_cmd(client, 3, msg, &len, resp);
1598         if (rv || (len < 2)) {
1599                 pr_warn(PFX "Error setting global enables: %d %d %2.2x\n",
1600                         rv, len, resp[2]);
1601                 rv = 0; /* Not fatal */
1602                 goto found;
1603         }
1604
1605         if (resp[2] == 0) {
1606                 /* A successful return means the alert is supported. */
1607                 ssif_info->supports_alert = true;
1608                 ssif_info->global_enables |= IPMI_BMC_RCV_MSG_INTR;
1609         }
1610
1611  found:
1612         ssif_info->intf_num = atomic_inc_return(&next_intf);
1613
1614         if (ssif_dbg_probe) {
1615                 pr_info("ssif_probe: i2c_probe found device at i2c address %x\n",
1616                         client->addr);
1617         }
1618
1619         spin_lock_init(&ssif_info->lock);
1620         ssif_info->ssif_state = SSIF_NORMAL;
1621         init_timer(&ssif_info->retry_timer);
1622         ssif_info->retry_timer.data = (unsigned long) ssif_info;
1623         ssif_info->retry_timer.function = retry_timeout;
1624
1625         for (i = 0; i < SSIF_NUM_STATS; i++)
1626                 atomic_set(&ssif_info->stats[i], 0);
1627
1628         if (ssif_info->supports_pec)
1629                 ssif_info->client->flags |= I2C_CLIENT_PEC;
1630
1631         ssif_info->handlers.owner = THIS_MODULE;
1632         ssif_info->handlers.start_processing = ssif_start_processing;
1633         ssif_info->handlers.get_smi_info = get_smi_info;
1634         ssif_info->handlers.sender = sender;
1635         ssif_info->handlers.request_events = request_events;
1636         ssif_info->handlers.inc_usecount = inc_usecount;
1637         ssif_info->handlers.dec_usecount = dec_usecount;
1638
1639         {
1640                 unsigned int thread_num;
1641
1642                 thread_num = ((ssif_info->client->adapter->nr << 8) |
1643                               ssif_info->client->addr);
1644                 init_completion(&ssif_info->wake_thread);
1645                 ssif_info->thread = kthread_run(ipmi_ssif_thread, ssif_info,
1646                                                "kssif%4.4x", thread_num);
1647                 if (IS_ERR(ssif_info->thread)) {
1648                         rv = PTR_ERR(ssif_info->thread);
1649                         dev_notice(&ssif_info->client->dev,
1650                                    "Could not start kernel thread: error %d\n",
1651                                    rv);
1652                         goto out;
1653                 }
1654         }
1655
1656         rv = ipmi_register_smi(&ssif_info->handlers,
1657                                ssif_info,
1658                                &ssif_info->device_id,
1659                                &ssif_info->client->dev,
1660                                slave_addr);
1661          if (rv) {
1662                 pr_err(PFX "Unable to register device: error %d\n", rv);
1663                 goto out;
1664         }
1665
1666         rv = ipmi_smi_add_proc_entry(ssif_info->intf, "type",
1667                                      &smi_type_proc_ops,
1668                                      ssif_info);
1669         if (rv) {
1670                 pr_err(PFX "Unable to create proc entry: %d\n", rv);
1671                 goto out_err_unreg;
1672         }
1673
1674         rv = ipmi_smi_add_proc_entry(ssif_info->intf, "ssif_stats",
1675                                      &smi_stats_proc_ops,
1676                                      ssif_info);
1677         if (rv) {
1678                 pr_err(PFX "Unable to create proc entry: %d\n", rv);
1679                 goto out_err_unreg;
1680         }
1681
1682  out:
1683         if (rv)
1684                 kfree(ssif_info);
1685         kfree(resp);
1686         return rv;
1687
1688  out_err_unreg:
1689         ipmi_unregister_smi(ssif_info->intf);
1690         goto out;
1691 }
1692
1693 static int ssif_adapter_handler(struct device *adev, void *opaque)
1694 {
1695         struct ssif_addr_info *addr_info = opaque;
1696
1697         if (adev->type != &i2c_adapter_type)
1698                 return 0;
1699
1700         i2c_new_device(to_i2c_adapter(adev), &addr_info->binfo);
1701
1702         if (!addr_info->adapter_name)
1703                 return 1; /* Only try the first I2C adapter by default. */
1704         return 0;
1705 }
1706
1707 static int new_ssif_client(int addr, char *adapter_name,
1708                            int debug, int slave_addr,
1709                            enum ipmi_addr_src addr_src)
1710 {
1711         struct ssif_addr_info *addr_info;
1712         int rv = 0;
1713
1714         mutex_lock(&ssif_infos_mutex);
1715         if (ssif_info_find(addr, adapter_name, false)) {
1716                 rv = -EEXIST;
1717                 goto out_unlock;
1718         }
1719
1720         addr_info = kzalloc(sizeof(*addr_info), GFP_KERNEL);
1721         if (!addr_info) {
1722                 rv = -ENOMEM;
1723                 goto out_unlock;
1724         }
1725
1726         if (adapter_name) {
1727                 addr_info->adapter_name = kstrdup(adapter_name, GFP_KERNEL);
1728                 if (!addr_info->adapter_name) {
1729                         kfree(addr_info);
1730                         rv = -ENOMEM;
1731                         goto out_unlock;
1732                 }
1733         }
1734
1735         strncpy(addr_info->binfo.type, DEVICE_NAME,
1736                 sizeof(addr_info->binfo.type));
1737         addr_info->binfo.addr = addr;
1738         addr_info->binfo.platform_data = addr_info;
1739         addr_info->debug = debug;
1740         addr_info->slave_addr = slave_addr;
1741         addr_info->addr_src = addr_src;
1742
1743         list_add_tail(&addr_info->link, &ssif_infos);
1744
1745         if (initialized)
1746                 i2c_for_each_dev(addr_info, ssif_adapter_handler);
1747         /* Otherwise address list will get it */
1748
1749 out_unlock:
1750         mutex_unlock(&ssif_infos_mutex);
1751         return rv;
1752 }
1753
1754 static void free_ssif_clients(void)
1755 {
1756         struct ssif_addr_info *info, *tmp;
1757
1758         mutex_lock(&ssif_infos_mutex);
1759         list_for_each_entry_safe(info, tmp, &ssif_infos, link) {
1760                 list_del(&info->link);
1761                 kfree(info->adapter_name);
1762                 kfree(info);
1763         }
1764         mutex_unlock(&ssif_infos_mutex);
1765 }
1766
1767 static unsigned short *ssif_address_list(void)
1768 {
1769         struct ssif_addr_info *info;
1770         unsigned int count = 0, i;
1771         unsigned short *address_list;
1772
1773         list_for_each_entry(info, &ssif_infos, link)
1774                 count++;
1775
1776         address_list = kzalloc(sizeof(*address_list) * (count + 1), GFP_KERNEL);
1777         if (!address_list)
1778                 return NULL;
1779
1780         i = 0;
1781         list_for_each_entry(info, &ssif_infos, link) {
1782                 unsigned short addr = info->binfo.addr;
1783                 int j;
1784
1785                 for (j = 0; j < i; j++) {
1786                         if (address_list[j] == addr)
1787                                 goto skip_addr;
1788                 }
1789                 address_list[i] = addr;
1790 skip_addr:
1791                 i++;
1792         }
1793         address_list[i] = I2C_CLIENT_END;
1794
1795         return address_list;
1796 }
1797
1798 #ifdef CONFIG_ACPI
1799 static const struct acpi_device_id ssif_acpi_match[] = {
1800         { "IPI0001", 0 },
1801         { },
1802 };
1803 MODULE_DEVICE_TABLE(acpi, ssif_acpi_match);
1804
1805 /*
1806  * Once we get an ACPI failure, we don't try any more, because we go
1807  * through the tables sequentially.  Once we don't find a table, there
1808  * are no more.
1809  */
1810 static int acpi_failure;
1811
1812 /*
1813  * Defined in the IPMI 2.0 spec.
1814  */
1815 struct SPMITable {
1816         s8      Signature[4];
1817         u32     Length;
1818         u8      Revision;
1819         u8      Checksum;
1820         s8      OEMID[6];
1821         s8      OEMTableID[8];
1822         s8      OEMRevision[4];
1823         s8      CreatorID[4];
1824         s8      CreatorRevision[4];
1825         u8      InterfaceType;
1826         u8      IPMIlegacy;
1827         s16     SpecificationRevision;
1828
1829         /*
1830          * Bit 0 - SCI interrupt supported
1831          * Bit 1 - I/O APIC/SAPIC
1832          */
1833         u8      InterruptType;
1834
1835         /*
1836          * If bit 0 of InterruptType is set, then this is the SCI
1837          * interrupt in the GPEx_STS register.
1838          */
1839         u8      GPE;
1840
1841         s16     Reserved;
1842
1843         /*
1844          * If bit 1 of InterruptType is set, then this is the I/O
1845          * APIC/SAPIC interrupt.
1846          */
1847         u32     GlobalSystemInterrupt;
1848
1849         /* The actual register address. */
1850         struct acpi_generic_address addr;
1851
1852         u8      UID[4];
1853
1854         s8      spmi_id[1]; /* A '\0' terminated array starts here. */
1855 };
1856
1857 static int try_init_spmi(struct SPMITable *spmi)
1858 {
1859         unsigned short myaddr;
1860
1861         if (num_addrs >= MAX_SSIF_BMCS)
1862                 return -1;
1863
1864         if (spmi->IPMIlegacy != 1) {
1865                 pr_warn("IPMI: Bad SPMI legacy: %d\n", spmi->IPMIlegacy);
1866                 return -ENODEV;
1867         }
1868
1869         if (spmi->InterfaceType != 4)
1870                 return -ENODEV;
1871
1872         if (spmi->addr.space_id != ACPI_ADR_SPACE_SMBUS) {
1873                 pr_warn(PFX "Invalid ACPI SSIF I/O Address type: %d\n",
1874                         spmi->addr.space_id);
1875                 return -EIO;
1876         }
1877
1878         myaddr = spmi->addr.address >> 1;
1879
1880         return new_ssif_client(myaddr, NULL, 0, 0, SI_SPMI);
1881 }
1882
1883 static void spmi_find_bmc(void)
1884 {
1885         acpi_status      status;
1886         struct SPMITable *spmi;
1887         int              i;
1888
1889         if (acpi_disabled)
1890                 return;
1891
1892         if (acpi_failure)
1893                 return;
1894
1895         for (i = 0; ; i++) {
1896                 status = acpi_get_table(ACPI_SIG_SPMI, i+1,
1897                                         (struct acpi_table_header **)&spmi);
1898                 if (status != AE_OK)
1899                         return;
1900
1901                 try_init_spmi(spmi);
1902         }
1903 }
1904 #else
1905 static void spmi_find_bmc(void) { }
1906 #endif
1907
1908 #ifdef CONFIG_DMI
1909 static int decode_dmi(const struct dmi_device *dmi_dev)
1910 {
1911         struct dmi_header *dm = dmi_dev->device_data;
1912         u8             *data = (u8 *) dm;
1913         u8             len = dm->length;
1914         unsigned short myaddr;
1915         int            slave_addr;
1916
1917         if (num_addrs >= MAX_SSIF_BMCS)
1918                 return -1;
1919
1920         if (len < 9)
1921                 return -1;
1922
1923         if (data[0x04] != 4) /* Not SSIF */
1924                 return -1;
1925
1926         if ((data[8] >> 1) == 0) {
1927                 /*
1928                  * Some broken systems put the I2C address in
1929                  * the slave address field.  We try to
1930                  * accommodate them here.
1931                  */
1932                 myaddr = data[6] >> 1;
1933                 slave_addr = 0;
1934         } else {
1935                 myaddr = data[8] >> 1;
1936                 slave_addr = data[6];
1937         }
1938
1939         return new_ssif_client(myaddr, NULL, 0, 0, SI_SMBIOS);
1940 }
1941
1942 static void dmi_iterator(void)
1943 {
1944         const struct dmi_device *dev = NULL;
1945
1946         while ((dev = dmi_find_device(DMI_DEV_TYPE_IPMI, NULL, dev)))
1947                 decode_dmi(dev);
1948 }
1949 #else
1950 static void dmi_iterator(void) { }
1951 #endif
1952
1953 static const struct i2c_device_id ssif_id[] = {
1954         { DEVICE_NAME, 0 },
1955         { }
1956 };
1957 MODULE_DEVICE_TABLE(i2c, ssif_id);
1958
1959 static struct i2c_driver ssif_i2c_driver = {
1960         .class          = I2C_CLASS_HWMON,
1961         .driver         = {
1962                 .owner                  = THIS_MODULE,
1963                 .name                   = DEVICE_NAME
1964         },
1965         .probe          = ssif_probe,
1966         .remove         = ssif_remove,
1967         .alert          = ssif_alert,
1968         .id_table       = ssif_id,
1969         .detect         = ssif_detect
1970 };
1971
1972 static int init_ipmi_ssif(void)
1973 {
1974         int i;
1975         int rv;
1976
1977         if (initialized)
1978                 return 0;
1979
1980         pr_info("IPMI SSIF Interface driver\n");
1981
1982         /* build list for i2c from addr list */
1983         for (i = 0; i < num_addrs; i++) {
1984                 rv = new_ssif_client(addr[i], adapter_name[i],
1985                                      dbg[i], slave_addrs[i],
1986                                      SI_HARDCODED);
1987                 if (rv)
1988                         pr_err(PFX
1989                                "Couldn't add hardcoded device at addr 0x%x\n",
1990                                addr[i]);
1991         }
1992
1993         if (ssif_tryacpi)
1994                 ssif_i2c_driver.driver.acpi_match_table =
1995                         ACPI_PTR(ssif_acpi_match);
1996         if (ssif_trydmi)
1997                 dmi_iterator();
1998         if (ssif_tryacpi)
1999                 spmi_find_bmc();
2000
2001         ssif_i2c_driver.address_list = ssif_address_list();
2002
2003         rv = i2c_add_driver(&ssif_i2c_driver);
2004         if (!rv)
2005                 initialized = true;
2006
2007         return rv;
2008 }
2009 module_init(init_ipmi_ssif);
2010
2011 static void cleanup_ipmi_ssif(void)
2012 {
2013         if (!initialized)
2014                 return;
2015
2016         initialized = false;
2017
2018         i2c_del_driver(&ssif_i2c_driver);
2019
2020         free_ssif_clients();
2021 }
2022 module_exit(cleanup_ipmi_ssif);
2023
2024 MODULE_AUTHOR("Todd C Davis <todd.c.davis@intel.com>, Corey Minyard <minyard@acm.org>");
2025 MODULE_DESCRIPTION("IPMI driver for management controllers on a SMBus");
2026 MODULE_LICENSE("GPL");