drivers/acpi/acpi_ipmi.c

   1 /*
   2  *  acpi_ipmi.c - ACPI IPMI opregion
   3  *
   4  *  Copyright (C) 2010, 2013 Intel Corporation
   5  *    Author: Zhao Yakui <yakui.zhao@intel.com>
   6  *            Lv Zheng <lv.zheng@intel.com>
   7  *
   8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or (at
  13  *  your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful, but
  16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *  General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with this program; if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  23  *
  24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  25  */
  26
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/init.h>
  30 #include <linux/types.h>
  31 #include <linux/delay.h>
  32 #include <linux/proc_fs.h>
  33 #include <linux/seq_file.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/list.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/io.h>
  38 #include <acpi/acpi_bus.h>
  39 #include <acpi/acpi_drivers.h>
  40 #include <linux/ipmi.h>
  41 #include <linux/device.h>
  42 #include <linux/pnp.h>
  43 #include <linux/spinlock.h>
  44
  45 MODULE_AUTHOR("Zhao Yakui");
  46 MODULE_DESCRIPTION("ACPI IPMI Opregion driver");
  47 MODULE_LICENSE("GPL");
  48
  49
  50 #define ACPI_IPMI_OK                    0
  51 #define ACPI_IPMI_TIMEOUT               0x10
  52 #define ACPI_IPMI_UNKNOWN               0x07
  53 /* the IPMI timeout is 5s */
  54 #define IPMI_TIMEOUT                    (5000)
  55 #define ACPI_IPMI_MAX_MSG_LENGTH        64
  56
  57 struct acpi_ipmi_device {
  58         /* the device list attached to driver_data.ipmi_devices */
  59         struct list_head head;
  60         /* the IPMI request message list */
  61         struct list_head tx_msg_list;
  62         spinlock_t      tx_msg_lock;
  63         acpi_handle handle;
  64         struct device *dev;
  65         ipmi_user_t     user_interface;
  66         int ipmi_ifnum; /* IPMI interface number */
  67         long curr_msgid;
  68         bool dead;
  69         struct kref kref;
  70 };
  71
  72 struct ipmi_driver_data {
  73         struct list_head        ipmi_devices;
  74         struct ipmi_smi_watcher bmc_events;
  75         struct ipmi_user_hndl   ipmi_hndlrs;
  76         struct mutex            ipmi_lock;
  77         /*
  78          * NOTE: IPMI System Interface Selection
  79          * There is no system interface specified by the IPMI operation
  80          * region access.  We try to select one system interface with ACPI
  81          * handle set.  IPMI messages passed from the ACPI codes are sent
  82          * to this selected global IPMI system interface.
  83          */
  84         struct acpi_ipmi_device *selected_smi;
  85 };
  86
  87 struct acpi_ipmi_msg {
  88         struct list_head head;
  89         /*
  90          * General speaking the addr type should be SI_ADDR_TYPE. And
  91          * the addr channel should be BMC.
  92          * In fact it can also be IPMB type. But we will have to
  93          * parse it from the Netfn command buffer. It is so complex
  94          * that it is skipped.
  95          */
  96         struct ipmi_addr addr;
  97         long tx_msgid;
  98         /* it is used to track whether the IPMI message is finished */
  99         struct completion tx_complete;
 100         struct kernel_ipmi_msg tx_message;
 101         int     msg_done;
 102         /* tx/rx data . And copy it from/to ACPI object buffer */
 103         u8      data[ACPI_IPMI_MAX_MSG_LENGTH];
 104         u8      rx_len;
 105         struct acpi_ipmi_device *device;
 106         struct kref     kref;
 107 };
 108
 109 /* IPMI request/response buffer per ACPI 4.0, sec 5.5.2.4.3.2 */
 110 struct acpi_ipmi_buffer {
 111         u8 status;
 112         u8 length;
 113         u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
 114 };
 115
 116 static void ipmi_register_bmc(int iface, struct device *dev);
 117 static void ipmi_bmc_gone(int iface);
 118 static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);
 119
 120 static struct ipmi_driver_data driver_data = {
 121         .ipmi_devices = LIST_HEAD_INIT(driver_data.ipmi_devices),
 122         .bmc_events = {
 123                 .owner = THIS_MODULE,
 124                 .new_smi = ipmi_register_bmc,
 125                 .smi_gone = ipmi_bmc_gone,
 126         },
 127         .ipmi_hndlrs = {
 128                 .ipmi_recv_hndl = ipmi_msg_handler,
 129         },
 130 };
 131
 132 static struct acpi_ipmi_device *
 133 ipmi_dev_alloc(int iface, struct device *dev, acpi_handle handle)
 134 {
 135         struct acpi_ipmi_device *ipmi_device;
 136         int err;
 137         ipmi_user_t user;
 138
 139         ipmi_device = kzalloc(sizeof(*ipmi_device), GFP_KERNEL);
 140         if (!ipmi_device)
 141                 return NULL;
 142
 143         kref_init(&ipmi_device->kref);
 144         INIT_LIST_HEAD(&ipmi_device->head);
 145         INIT_LIST_HEAD(&ipmi_device->tx_msg_list);
 146         spin_lock_init(&ipmi_device->tx_msg_lock);
 147
 148         ipmi_device->handle = handle;
 149         ipmi_device->dev = get_device(dev);
 150         ipmi_device->ipmi_ifnum = iface;
 151
 152         err = ipmi_create_user(iface, &driver_data.ipmi_hndlrs,
 153                                ipmi_device, &user);
 154         if (err) {
 155                 put_device(dev);
 156                 kfree(ipmi_device);
 157                 return NULL;
 158         }
 159         ipmi_device->user_interface = user;
 160
 161         return ipmi_device;
 162 }
 163
 164 static void ipmi_dev_release(struct acpi_ipmi_device *ipmi_device)
 165 {
 166         ipmi_destroy_user(ipmi_device->user_interface);
 167         put_device(ipmi_device->dev);
 168         kfree(ipmi_device);
 169 }
 170
 171 static void ipmi_dev_release_kref(struct kref *kref)
 172 {
 173         struct acpi_ipmi_device *ipmi =
 174                 container_of(kref, struct acpi_ipmi_device, kref);
 175
 176         ipmi_dev_release(ipmi);
 177 }
 178
 179 static void __ipmi_dev_kill(struct acpi_ipmi_device *ipmi_device)
 180 {
 181         list_del(&ipmi_device->head);
 182         if (driver_data.selected_smi == ipmi_device)
 183                 driver_data.selected_smi = NULL;
 184         /*
 185          * Always setting dead flag after deleting from the list or
 186          * list_for_each_entry() codes must get changed.
 187          */
 188         ipmi_device->dead = true;
 189 }
 190
 191 static struct acpi_ipmi_device *acpi_ipmi_dev_get(void)
 192 {
 193         struct acpi_ipmi_device *ipmi_device = NULL;
 194
 195         mutex_lock(&driver_data.ipmi_lock);
 196         if (driver_data.selected_smi) {
 197                 ipmi_device = driver_data.selected_smi;
 198                 kref_get(&ipmi_device->kref);
 199         }
 200         mutex_unlock(&driver_data.ipmi_lock);
 201
 202         return ipmi_device;
 203 }
 204
 205 static void acpi_ipmi_dev_put(struct acpi_ipmi_device *ipmi_device)
 206 {
 207         kref_put(&ipmi_device->kref, ipmi_dev_release_kref);
 208 }
 209
 210 static struct acpi_ipmi_msg *ipmi_msg_alloc(void)
 211 {
 212         struct acpi_ipmi_device *ipmi;
 213         struct acpi_ipmi_msg *ipmi_msg;
 214
 215         ipmi = acpi_ipmi_dev_get();
 216         if (!ipmi)
 217                 return NULL;
 218         ipmi_msg = kzalloc(sizeof(struct acpi_ipmi_msg), GFP_KERNEL);
 219         if (!ipmi_msg) {
 220                 acpi_ipmi_dev_put(ipmi);
 221                 return NULL;
 222         }
 223         kref_init(&ipmi_msg->kref);
 224         init_completion(&ipmi_msg->tx_complete);
 225         INIT_LIST_HEAD(&ipmi_msg->head);
 226         ipmi_msg->device = ipmi;
 227         ipmi_msg->msg_done = ACPI_IPMI_UNKNOWN;
 228         return ipmi_msg;
 229 }
 230
 231 static void ipmi_msg_release(struct acpi_ipmi_msg *tx_msg)
 232 {
 233         acpi_ipmi_dev_put(tx_msg->device);
 234         kfree(tx_msg);
 235 }
 236
 237 static void ipmi_msg_release_kref(struct kref *kref)
 238 {
 239         struct acpi_ipmi_msg *tx_msg =
 240                 container_of(kref, struct acpi_ipmi_msg, kref);
 241
 242         ipmi_msg_release(tx_msg);
 243 }
 244
 245 static struct acpi_ipmi_msg *acpi_ipmi_msg_get(struct acpi_ipmi_msg *tx_msg)
 246 {
 247         kref_get(&tx_msg->kref);
 248
 249         return tx_msg;
 250 }
 251
 252 static void acpi_ipmi_msg_put(struct acpi_ipmi_msg *tx_msg)
 253 {
 254         kref_put(&tx_msg->kref, ipmi_msg_release_kref);
 255 }
 256
 257 #define         IPMI_OP_RGN_NETFN(offset)       ((offset >> 8) & 0xff)
 258 #define         IPMI_OP_RGN_CMD(offset)         (offset & 0xff)
 259 static int acpi_format_ipmi_request(struct acpi_ipmi_msg *tx_msg,
 260                                 acpi_physical_address address,
 261                                 acpi_integer *value)
 262 {
 263         struct kernel_ipmi_msg *msg;
 264         struct acpi_ipmi_buffer *buffer;
 265         struct acpi_ipmi_device *device;
 266         unsigned long flags;
 267
 268         msg = &tx_msg->tx_message;
 269         /*
 270          * IPMI network function and command are encoded in the address
 271          * within the IPMI OpRegion; see ACPI 4.0, sec 5.5.2.4.3.
 272          */
 273         msg->netfn = IPMI_OP_RGN_NETFN(address);
 274         msg->cmd = IPMI_OP_RGN_CMD(address);
 275         msg->data = tx_msg->data;
 276         /*
 277          * value is the parameter passed by the IPMI opregion space handler.
 278          * It points to the IPMI request message buffer
 279          */
 280         buffer = (struct acpi_ipmi_buffer *)value;
 281         /* copy the tx message data */
 282         if (buffer->length > ACPI_IPMI_MAX_MSG_LENGTH) {
 283                 dev_WARN_ONCE(tx_msg->device->dev, true,
 284                               "Unexpected request (msg len %d).\n",
 285                               buffer->length);
 286                 return -EINVAL;
 287         }
 288         msg->data_len = buffer->length;
 289         memcpy(tx_msg->data, buffer->data, msg->data_len);
 290         /*
 291          * now the default type is SYSTEM_INTERFACE and channel type is BMC.
 292          * If the netfn is APP_REQUEST and the cmd is SEND_MESSAGE,
 293          * the addr type should be changed to IPMB. Then we will have to parse
 294          * the IPMI request message buffer to get the IPMB address.
 295          * If so, please fix me.
 296          */
 297         tx_msg->addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
 298         tx_msg->addr.channel = IPMI_BMC_CHANNEL;
 299         tx_msg->addr.data[0] = 0;
 300
 301         /* Get the msgid */
 302         device = tx_msg->device;
 303         spin_lock_irqsave(&device->tx_msg_lock, flags);
 304         device->curr_msgid++;
 305         tx_msg->tx_msgid = device->curr_msgid;
 306         spin_unlock_irqrestore(&device->tx_msg_lock, flags);
 307         return 0;
 308 }
 309
 310 static void acpi_format_ipmi_response(struct acpi_ipmi_msg *msg,
 311                 acpi_integer *value)
 312 {
 313         struct acpi_ipmi_buffer *buffer;
 314
 315         /*
 316          * value is also used as output parameter. It represents the response
 317          * IPMI message returned by IPMI command.
 318          */
 319         buffer = (struct acpi_ipmi_buffer *)value;
 320         /*
 321          * If the flag of msg_done is not set, it means that the IPMI command is
 322          * not executed correctly.
 323          */
 324         buffer->status = msg->msg_done;
 325         if (msg->msg_done != ACPI_IPMI_OK)
 326                 return;
 327         /*
 328          * If the IPMI response message is obtained correctly, the status code
 329          * will be ACPI_IPMI_OK
 330          */
 331         buffer->length = msg->rx_len;
 332         memcpy(buffer->data, msg->data, msg->rx_len);
 333 }
 334
 335 static void ipmi_flush_tx_msg(struct acpi_ipmi_device *ipmi)
 336 {
 337         struct acpi_ipmi_msg *tx_msg;
 338         unsigned long flags;
 339
 340         /*
 341          * NOTE: On-going ipmi_recv_msg
 342          * ipmi_msg_handler() may still be invoked by ipmi_si after
 343          * flushing.  But it is safe to do a fast flushing on module_exit()
 344          * without waiting for all ipmi_recv_msg(s) to complete from
 345          * ipmi_msg_handler() as it is ensured by ipmi_si that all
 346          * ipmi_recv_msg(s) are freed after invoking ipmi_destroy_user().
 347          */
 348         spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
 349         while (!list_empty(&ipmi->tx_msg_list)) {
 350                 tx_msg = list_first_entry(&ipmi->tx_msg_list,
 351                                           struct acpi_ipmi_msg,
 352                                           head);
 353                 list_del(&tx_msg->head);
 354                 spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
 355
 356                 /* wake up the sleep thread on the Tx msg */
 357                 complete(&tx_msg->tx_complete);
 358                 acpi_ipmi_msg_put(tx_msg);
 359                 spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
 360         }
 361         spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
 362 }
 363
 364 static void ipmi_cancel_tx_msg(struct acpi_ipmi_device *ipmi,
 365                                struct acpi_ipmi_msg *msg)
 366 {
 367         struct acpi_ipmi_msg *tx_msg, *temp;
 368         bool msg_found = false;
 369         unsigned long flags;
 370
 371         spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
 372         list_for_each_entry_safe(tx_msg, temp, &ipmi->tx_msg_list, head) {
 373                 if (msg == tx_msg) {
 374                         msg_found = true;
 375                         list_del(&tx_msg->head);
 376                         break;
 377                 }
 378         }
 379         spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
 380
 381         if (msg_found)
 382                 acpi_ipmi_msg_put(tx_msg);
 383 }
 384
 385 static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data)
 386 {
 387         struct acpi_ipmi_device *ipmi_device = user_msg_data;
 388         bool msg_found = false;
 389         struct acpi_ipmi_msg *tx_msg, *temp;
 390         struct device *dev = ipmi_device->dev;
 391         unsigned long flags;
 392
 393         if (msg->user != ipmi_device->user_interface) {
 394                 dev_warn(dev, "Unexpected response is returned. "
 395                         "returned user %p, expected user %p\n",
 396                         msg->user, ipmi_device->user_interface);
 397                 goto out_msg;
 398         }
 399         spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
 400         list_for_each_entry_safe(tx_msg, temp, &ipmi_device->tx_msg_list, head) {
 401                 if (msg->msgid == tx_msg->tx_msgid) {
 402                         msg_found = true;
 403                         list_del(&tx_msg->head);
 404                         break;
 405                 }
 406         }
 407         spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
 408
 409         if (!msg_found) {
 410                 dev_warn(dev, "Unexpected response (msg id %ld) is "
 411                         "returned.\n", msg->msgid);
 412                 goto out_msg;
 413         }
 414
 415         /* copy the response data to Rx_data buffer */
 416         if (msg->msg.data_len > ACPI_IPMI_MAX_MSG_LENGTH) {
 417                 dev_WARN_ONCE(dev, true,
 418                               "Unexpected response (msg len %d).\n",
 419                               msg->msg.data_len);
 420                 goto out_comp;
 421         }
 422         /* response msg is an error msg */
 423         msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
 424         if (msg->recv_type == IPMI_RESPONSE_RECV_TYPE &&
 425             msg->msg.data_len == 1) {
 426                 if (msg->msg.data[0] == IPMI_TIMEOUT_COMPLETION_CODE) {
 427                         dev_WARN_ONCE(dev, true,
 428                                       "Unexpected response (timeout).\n");
 429                         tx_msg->msg_done = ACPI_IPMI_TIMEOUT;
 430                 }
 431                 goto out_comp;
 432         }
 433         tx_msg->rx_len = msg->msg.data_len;
 434         memcpy(tx_msg->data, msg->msg.data, tx_msg->rx_len);
 435         tx_msg->msg_done = ACPI_IPMI_OK;
 436 out_comp:
 437         complete(&tx_msg->tx_complete);
 438         acpi_ipmi_msg_put(tx_msg);
 439 out_msg:
 440         ipmi_free_recv_msg(msg);
 441 };
 442
 443 static void ipmi_register_bmc(int iface, struct device *dev)
 444 {
 445         struct acpi_ipmi_device *ipmi_device, *temp;
 446         int err;
 447         struct ipmi_smi_info smi_data;
 448         acpi_handle handle;
 449
 450         err = ipmi_get_smi_info(iface, &smi_data);
 451
 452         if (err)
 453                 return;
 454
 455         if (smi_data.addr_src != SI_ACPI)
 456                 goto err_ref;
 457         handle = smi_data.addr_info.acpi_info.acpi_handle;
 458         if (!handle)
 459                 goto err_ref;
 460
 461         ipmi_device = ipmi_dev_alloc(iface, smi_data.dev, handle);
 462         if (!ipmi_device) {
 463                 dev_warn(smi_data.dev, "Can't create IPMI user interface\n");
 464                 goto err_ref;
 465         }
 466
 467         mutex_lock(&driver_data.ipmi_lock);
 468         list_for_each_entry(temp, &driver_data.ipmi_devices, head) {
 469                 /*
 470                  * if the corresponding ACPI handle is already added
 471                  * to the device list, don't add it again.
 472                  */
 473                 if (temp->handle == handle)
 474                         goto err_lock;
 475         }
 476
 477         if (!driver_data.selected_smi)
 478                 driver_data.selected_smi = ipmi_device;
 479         list_add_tail(&ipmi_device->head, &driver_data.ipmi_devices);
 480         mutex_unlock(&driver_data.ipmi_lock);
 481         put_device(smi_data.dev);
 482         return;
 483
 484 err_lock:
 485         mutex_unlock(&driver_data.ipmi_lock);
 486         ipmi_dev_release(ipmi_device);
 487 err_ref:
 488         put_device(smi_data.dev);
 489         return;
 490 }
 491
 492 static void ipmi_bmc_gone(int iface)
 493 {
 494         struct acpi_ipmi_device *ipmi_device, *temp;
 495         bool dev_found = false;
 496
 497         mutex_lock(&driver_data.ipmi_lock);
 498         list_for_each_entry_safe(ipmi_device, temp,
 499                                 &driver_data.ipmi_devices, head) {
 500                 if (ipmi_device->ipmi_ifnum != iface) {
 501                         dev_found = true;
 502                         __ipmi_dev_kill(ipmi_device);
 503                         break;
 504                 }
 505         }
 506         if (!driver_data.selected_smi)
 507                 driver_data.selected_smi = list_first_entry_or_null(
 508                                         &driver_data.ipmi_devices,
 509                                         struct acpi_ipmi_device, head);
 510         mutex_unlock(&driver_data.ipmi_lock);
 511         if (dev_found) {
 512                 ipmi_flush_tx_msg(ipmi_device);
 513                 acpi_ipmi_dev_put(ipmi_device);
 514         }
 515 }
 516 /* --------------------------------------------------------------------------
 517  *                      Address Space Management
 518  * -------------------------------------------------------------------------- */
 519 /*
 520  * This is the IPMI opregion space handler.
 521  * @function: indicates the read/write. In fact as the IPMI message is driven
 522  * by command, only write is meaningful.
 523  * @address: This contains the netfn/command of IPMI request message.
 524  * @bits   : not used.
 525  * @value  : it is an in/out parameter. It points to the IPMI message buffer.
 526  *           Before the IPMI message is sent, it represents the actual request
 527  *           IPMI message. After the IPMI message is finished, it represents
 528  *           the response IPMI message returned by IPMI command.
 529  * @handler_context: IPMI device context.
 530  */
 531
 532 static acpi_status
 533 acpi_ipmi_space_handler(u32 function, acpi_physical_address address,
 534                       u32 bits, acpi_integer *value,
 535                       void *handler_context, void *region_context)
 536 {
 537         struct acpi_ipmi_msg *tx_msg;
 538         struct acpi_ipmi_device *ipmi_device;
 539         int err;
 540         acpi_status status;
 541         unsigned long flags;
 542         /*
 543          * IPMI opregion message.
 544          * IPMI message is firstly written to the BMC and system software
 545          * can get the respsonse. So it is unmeaningful for the read access
 546          * of IPMI opregion.
 547          */
 548         if ((function & ACPI_IO_MASK) == ACPI_READ)
 549                 return AE_TYPE;
 550
 551         tx_msg = ipmi_msg_alloc();
 552         if (!tx_msg)
 553                 return AE_NOT_EXIST;
 554
 555         ipmi_device = tx_msg->device;
 556
 557         if (acpi_format_ipmi_request(tx_msg, address, value) != 0) {
 558                 ipmi_msg_release(tx_msg);
 559                 return AE_TYPE;
 560         }
 561         acpi_ipmi_msg_get(tx_msg);
 562         mutex_lock(&driver_data.ipmi_lock);
 563         /* Do not add a tx_msg that can not be flushed. */
 564         if (ipmi_device->dead) {
 565                 mutex_unlock(&driver_data.ipmi_lock);
 566                 ipmi_msg_release(tx_msg);
 567                 return AE_NOT_EXIST;
 568         }
 569         spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
 570         list_add_tail(&tx_msg->head, &ipmi_device->tx_msg_list);
 571         spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
 572         mutex_unlock(&driver_data.ipmi_lock);
 573         err = ipmi_request_settime(ipmi_device->user_interface,
 574                                         &tx_msg->addr,
 575                                         tx_msg->tx_msgid,
 576                                         &tx_msg->tx_message,
 577                                         NULL, 0, 0, IPMI_TIMEOUT);
 578         if (err) {
 579                 status = AE_ERROR;
 580                 goto out_msg;
 581         }
 582         wait_for_completion(&tx_msg->tx_complete);
 583         acpi_format_ipmi_response(tx_msg, value);
 584         status = AE_OK;
 585
 586 out_msg:
 587         ipmi_cancel_tx_msg(ipmi_device, tx_msg);
 588         acpi_ipmi_msg_put(tx_msg);
 589         return status;
 590 }
 591
 592 static int __init acpi_ipmi_init(void)
 593 {
 594         int result = 0;
 595         acpi_status status;
 596
 597         if (acpi_disabled)
 598                 return result;
 599
 600         mutex_init(&driver_data.ipmi_lock);
 601
 602         status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
 603                                 ACPI_ADR_SPACE_IPMI, &acpi_ipmi_space_handler,
 604                                 NULL, NULL);
 605         if (ACPI_FAILURE(status)) {
 606                 pr_warn("Can't register IPMI opregion space handle\n");
 607                 return -EINVAL;
 608         }
 609         result = ipmi_smi_watcher_register(&driver_data.bmc_events);
 610         if (result)
 611                 pr_err("Can't register IPMI system interface watcher\n");
 612
 613         return result;
 614 }
 615
 616 static void __exit acpi_ipmi_exit(void)
 617 {
 618         struct acpi_ipmi_device *ipmi_device;
 619
 620         if (acpi_disabled)
 621                 return;
 622
 623         ipmi_smi_watcher_unregister(&driver_data.bmc_events);
 624
 625         /*
 626          * When one smi_watcher is unregistered, it is only deleted
 627          * from the smi_watcher list. But the smi_gone callback function
 628          * is not called. So explicitly uninstall the ACPI IPMI oregion
 629          * handler and free it.
 630          */
 631         mutex_lock(&driver_data.ipmi_lock);
 632         while (!list_empty(&driver_data.ipmi_devices)) {
 633                 ipmi_device = list_first_entry(&driver_data.ipmi_devices,
 634                                                struct acpi_ipmi_device,
 635                                                head);
 636                 __ipmi_dev_kill(ipmi_device);
 637                 mutex_unlock(&driver_data.ipmi_lock);
 638
 639                 ipmi_flush_tx_msg(ipmi_device);
 640                 acpi_ipmi_dev_put(ipmi_device);
 641
 642                 mutex_lock(&driver_data.ipmi_lock);
 643         }
 644         mutex_unlock(&driver_data.ipmi_lock);
 645         acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
 646                                 ACPI_ADR_SPACE_IPMI, &acpi_ipmi_space_handler);
 647 }
 648
 649 module_init(acpi_ipmi_init);
 650 module_exit(acpi_ipmi_exit);