GNU Linux-libre 4.4.289-gnu1
[releases.git] / 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  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
21  */
22
23 #include <linux/module.h>
24 #include <linux/acpi.h>
25 #include <linux/ipmi.h>
26 #include <linux/spinlock.h>
27
28 MODULE_AUTHOR("Zhao Yakui");
29 MODULE_DESCRIPTION("ACPI IPMI Opregion driver");
30 MODULE_LICENSE("GPL");
31
32 #define ACPI_IPMI_OK                    0
33 #define ACPI_IPMI_TIMEOUT               0x10
34 #define ACPI_IPMI_UNKNOWN               0x07
35 /* the IPMI timeout is 5s */
36 #define IPMI_TIMEOUT                    (5000)
37 #define ACPI_IPMI_MAX_MSG_LENGTH        64
38
39 struct acpi_ipmi_device {
40         /* the device list attached to driver_data.ipmi_devices */
41         struct list_head head;
42
43         /* the IPMI request message list */
44         struct list_head tx_msg_list;
45
46         spinlock_t tx_msg_lock;
47         acpi_handle handle;
48         struct device *dev;
49         ipmi_user_t user_interface;
50         int ipmi_ifnum; /* IPMI interface number */
51         long curr_msgid;
52         bool dead;
53         struct kref kref;
54 };
55
56 struct ipmi_driver_data {
57         struct list_head ipmi_devices;
58         struct ipmi_smi_watcher bmc_events;
59         struct ipmi_user_hndl ipmi_hndlrs;
60         struct mutex ipmi_lock;
61
62         /*
63          * NOTE: IPMI System Interface Selection
64          * There is no system interface specified by the IPMI operation
65          * region access.  We try to select one system interface with ACPI
66          * handle set.  IPMI messages passed from the ACPI codes are sent
67          * to this selected global IPMI system interface.
68          */
69         struct acpi_ipmi_device *selected_smi;
70 };
71
72 struct acpi_ipmi_msg {
73         struct list_head head;
74
75         /*
76          * General speaking the addr type should be SI_ADDR_TYPE. And
77          * the addr channel should be BMC.
78          * In fact it can also be IPMB type. But we will have to
79          * parse it from the Netfn command buffer. It is so complex
80          * that it is skipped.
81          */
82         struct ipmi_addr addr;
83         long tx_msgid;
84
85         /* it is used to track whether the IPMI message is finished */
86         struct completion tx_complete;
87
88         struct kernel_ipmi_msg tx_message;
89         int msg_done;
90
91         /* tx/rx data . And copy it from/to ACPI object buffer */
92         u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
93         u8 rx_len;
94
95         struct acpi_ipmi_device *device;
96         struct kref kref;
97 };
98
99 /* IPMI request/response buffer per ACPI 4.0, sec 5.5.2.4.3.2 */
100 struct acpi_ipmi_buffer {
101         u8 status;
102         u8 length;
103         u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
104 };
105
106 static void ipmi_register_bmc(int iface, struct device *dev);
107 static void ipmi_bmc_gone(int iface);
108 static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);
109
110 static struct ipmi_driver_data driver_data = {
111         .ipmi_devices = LIST_HEAD_INIT(driver_data.ipmi_devices),
112         .bmc_events = {
113                 .owner = THIS_MODULE,
114                 .new_smi = ipmi_register_bmc,
115                 .smi_gone = ipmi_bmc_gone,
116         },
117         .ipmi_hndlrs = {
118                 .ipmi_recv_hndl = ipmi_msg_handler,
119         },
120         .ipmi_lock = __MUTEX_INITIALIZER(driver_data.ipmi_lock)
121 };
122
123 static struct acpi_ipmi_device *
124 ipmi_dev_alloc(int iface, struct device *dev, acpi_handle handle)
125 {
126         struct acpi_ipmi_device *ipmi_device;
127         int err;
128         ipmi_user_t user;
129
130         ipmi_device = kzalloc(sizeof(*ipmi_device), GFP_KERNEL);
131         if (!ipmi_device)
132                 return NULL;
133
134         kref_init(&ipmi_device->kref);
135         INIT_LIST_HEAD(&ipmi_device->head);
136         INIT_LIST_HEAD(&ipmi_device->tx_msg_list);
137         spin_lock_init(&ipmi_device->tx_msg_lock);
138         ipmi_device->handle = handle;
139         ipmi_device->dev = get_device(dev);
140         ipmi_device->ipmi_ifnum = iface;
141
142         err = ipmi_create_user(iface, &driver_data.ipmi_hndlrs,
143                                ipmi_device, &user);
144         if (err) {
145                 put_device(dev);
146                 kfree(ipmi_device);
147                 return NULL;
148         }
149         ipmi_device->user_interface = user;
150
151         return ipmi_device;
152 }
153
154 static void ipmi_dev_release(struct acpi_ipmi_device *ipmi_device)
155 {
156         ipmi_destroy_user(ipmi_device->user_interface);
157         put_device(ipmi_device->dev);
158         kfree(ipmi_device);
159 }
160
161 static void ipmi_dev_release_kref(struct kref *kref)
162 {
163         struct acpi_ipmi_device *ipmi =
164                 container_of(kref, struct acpi_ipmi_device, kref);
165
166         ipmi_dev_release(ipmi);
167 }
168
169 static void __ipmi_dev_kill(struct acpi_ipmi_device *ipmi_device)
170 {
171         list_del(&ipmi_device->head);
172         if (driver_data.selected_smi == ipmi_device)
173                 driver_data.selected_smi = NULL;
174
175         /*
176          * Always setting dead flag after deleting from the list or
177          * list_for_each_entry() codes must get changed.
178          */
179         ipmi_device->dead = true;
180 }
181
182 static struct acpi_ipmi_device *acpi_ipmi_dev_get(void)
183 {
184         struct acpi_ipmi_device *ipmi_device = NULL;
185
186         mutex_lock(&driver_data.ipmi_lock);
187         if (driver_data.selected_smi) {
188                 ipmi_device = driver_data.selected_smi;
189                 kref_get(&ipmi_device->kref);
190         }
191         mutex_unlock(&driver_data.ipmi_lock);
192
193         return ipmi_device;
194 }
195
196 static void acpi_ipmi_dev_put(struct acpi_ipmi_device *ipmi_device)
197 {
198         kref_put(&ipmi_device->kref, ipmi_dev_release_kref);
199 }
200
201 static struct acpi_ipmi_msg *ipmi_msg_alloc(void)
202 {
203         struct acpi_ipmi_device *ipmi;
204         struct acpi_ipmi_msg *ipmi_msg;
205
206         ipmi = acpi_ipmi_dev_get();
207         if (!ipmi)
208                 return NULL;
209
210         ipmi_msg = kzalloc(sizeof(struct acpi_ipmi_msg), GFP_KERNEL);
211         if (!ipmi_msg) {
212                 acpi_ipmi_dev_put(ipmi);
213                 return NULL;
214         }
215
216         kref_init(&ipmi_msg->kref);
217         init_completion(&ipmi_msg->tx_complete);
218         INIT_LIST_HEAD(&ipmi_msg->head);
219         ipmi_msg->device = ipmi;
220         ipmi_msg->msg_done = ACPI_IPMI_UNKNOWN;
221
222         return ipmi_msg;
223 }
224
225 static void ipmi_msg_release(struct acpi_ipmi_msg *tx_msg)
226 {
227         acpi_ipmi_dev_put(tx_msg->device);
228         kfree(tx_msg);
229 }
230
231 static void ipmi_msg_release_kref(struct kref *kref)
232 {
233         struct acpi_ipmi_msg *tx_msg =
234                 container_of(kref, struct acpi_ipmi_msg, kref);
235
236         ipmi_msg_release(tx_msg);
237 }
238
239 static struct acpi_ipmi_msg *acpi_ipmi_msg_get(struct acpi_ipmi_msg *tx_msg)
240 {
241         kref_get(&tx_msg->kref);
242
243         return tx_msg;
244 }
245
246 static void acpi_ipmi_msg_put(struct acpi_ipmi_msg *tx_msg)
247 {
248         kref_put(&tx_msg->kref, ipmi_msg_release_kref);
249 }
250
251 #define IPMI_OP_RGN_NETFN(offset)       ((offset >> 8) & 0xff)
252 #define IPMI_OP_RGN_CMD(offset)         (offset & 0xff)
253 static int acpi_format_ipmi_request(struct acpi_ipmi_msg *tx_msg,
254                                     acpi_physical_address address,
255                                     acpi_integer *value)
256 {
257         struct kernel_ipmi_msg *msg;
258         struct acpi_ipmi_buffer *buffer;
259         struct acpi_ipmi_device *device;
260         unsigned long flags;
261
262         msg = &tx_msg->tx_message;
263
264         /*
265          * IPMI network function and command are encoded in the address
266          * within the IPMI OpRegion; see ACPI 4.0, sec 5.5.2.4.3.
267          */
268         msg->netfn = IPMI_OP_RGN_NETFN(address);
269         msg->cmd = IPMI_OP_RGN_CMD(address);
270         msg->data = tx_msg->data;
271
272         /*
273          * value is the parameter passed by the IPMI opregion space handler.
274          * It points to the IPMI request message buffer
275          */
276         buffer = (struct acpi_ipmi_buffer *)value;
277
278         /* copy the tx message data */
279         if (buffer->length > ACPI_IPMI_MAX_MSG_LENGTH) {
280                 dev_WARN_ONCE(tx_msg->device->dev, true,
281                               "Unexpected request (msg len %d).\n",
282                               buffer->length);
283                 return -EINVAL;
284         }
285         msg->data_len = buffer->length;
286         memcpy(tx_msg->data, buffer->data, msg->data_len);
287
288         /*
289          * now the default type is SYSTEM_INTERFACE and channel type is BMC.
290          * If the netfn is APP_REQUEST and the cmd is SEND_MESSAGE,
291          * the addr type should be changed to IPMB. Then we will have to parse
292          * the IPMI request message buffer to get the IPMB address.
293          * If so, please fix me.
294          */
295         tx_msg->addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
296         tx_msg->addr.channel = IPMI_BMC_CHANNEL;
297         tx_msg->addr.data[0] = 0;
298
299         /* Get the msgid */
300         device = tx_msg->device;
301
302         spin_lock_irqsave(&device->tx_msg_lock, flags);
303         device->curr_msgid++;
304         tx_msg->tx_msgid = device->curr_msgid;
305         spin_unlock_irqrestore(&device->tx_msg_lock, flags);
306
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         /*
322          * If the flag of msg_done is not set, it means that the IPMI command is
323          * not executed correctly.
324          */
325         buffer->status = msg->msg_done;
326         if (msg->msg_done != ACPI_IPMI_OK)
327                 return;
328
329         /*
330          * If the IPMI response message is obtained correctly, the status code
331          * will be ACPI_IPMI_OK
332          */
333         buffer->length = msg->rx_len;
334         memcpy(buffer->data, msg->data, msg->rx_len);
335 }
336
337 static void ipmi_flush_tx_msg(struct acpi_ipmi_device *ipmi)
338 {
339         struct acpi_ipmi_msg *tx_msg;
340         unsigned long flags;
341
342         /*
343          * NOTE: On-going ipmi_recv_msg
344          * ipmi_msg_handler() may still be invoked by ipmi_si after
345          * flushing.  But it is safe to do a fast flushing on module_exit()
346          * without waiting for all ipmi_recv_msg(s) to complete from
347          * ipmi_msg_handler() as it is ensured by ipmi_si that all
348          * ipmi_recv_msg(s) are freed after invoking ipmi_destroy_user().
349          */
350         spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
351         while (!list_empty(&ipmi->tx_msg_list)) {
352                 tx_msg = list_first_entry(&ipmi->tx_msg_list,
353                                           struct acpi_ipmi_msg,
354                                           head);
355                 list_del(&tx_msg->head);
356                 spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
357
358                 /* wake up the sleep thread on the Tx msg */
359                 complete(&tx_msg->tx_complete);
360                 acpi_ipmi_msg_put(tx_msg);
361                 spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
362         }
363         spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
364 }
365
366 static void ipmi_cancel_tx_msg(struct acpi_ipmi_device *ipmi,
367                                struct acpi_ipmi_msg *msg)
368 {
369         struct acpi_ipmi_msg *tx_msg, *temp;
370         bool msg_found = false;
371         unsigned long flags;
372
373         spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
374         list_for_each_entry_safe(tx_msg, temp, &ipmi->tx_msg_list, head) {
375                 if (msg == tx_msg) {
376                         msg_found = true;
377                         list_del(&tx_msg->head);
378                         break;
379                 }
380         }
381         spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
382
383         if (msg_found)
384                 acpi_ipmi_msg_put(tx_msg);
385 }
386
387 static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data)
388 {
389         struct acpi_ipmi_device *ipmi_device = user_msg_data;
390         bool msg_found = false;
391         struct acpi_ipmi_msg *tx_msg, *temp;
392         struct device *dev = ipmi_device->dev;
393         unsigned long flags;
394
395         if (msg->user != ipmi_device->user_interface) {
396                 dev_warn(dev,
397                          "Unexpected response is returned. returned user %p, expected user %p\n",
398                          msg->user, ipmi_device->user_interface);
399                 goto out_msg;
400         }
401
402         spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
403         list_for_each_entry_safe(tx_msg, temp, &ipmi_device->tx_msg_list, head) {
404                 if (msg->msgid == tx_msg->tx_msgid) {
405                         msg_found = true;
406                         list_del(&tx_msg->head);
407                         break;
408                 }
409         }
410         spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
411
412         if (!msg_found) {
413                 dev_warn(dev,
414                          "Unexpected response (msg id %ld) is returned.\n",
415                          msg->msgid);
416                 goto out_msg;
417         }
418
419         /* copy the response data to Rx_data buffer */
420         if (msg->msg.data_len > ACPI_IPMI_MAX_MSG_LENGTH) {
421                 dev_WARN_ONCE(dev, true,
422                               "Unexpected response (msg len %d).\n",
423                               msg->msg.data_len);
424                 goto out_comp;
425         }
426
427         /* response msg is an error msg */
428         msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
429         if (msg->recv_type == IPMI_RESPONSE_RECV_TYPE &&
430             msg->msg.data_len == 1) {
431                 if (msg->msg.data[0] == IPMI_TIMEOUT_COMPLETION_CODE) {
432                         dev_WARN_ONCE(dev, true,
433                                       "Unexpected response (timeout).\n");
434                         tx_msg->msg_done = ACPI_IPMI_TIMEOUT;
435                 }
436                 goto out_comp;
437         }
438
439         tx_msg->rx_len = msg->msg.data_len;
440         memcpy(tx_msg->data, msg->msg.data, tx_msg->rx_len);
441         tx_msg->msg_done = ACPI_IPMI_OK;
442
443 out_comp:
444         complete(&tx_msg->tx_complete);
445         acpi_ipmi_msg_put(tx_msg);
446 out_msg:
447         ipmi_free_recv_msg(msg);
448 }
449
450 static void ipmi_register_bmc(int iface, struct device *dev)
451 {
452         struct acpi_ipmi_device *ipmi_device, *temp;
453         int err;
454         struct ipmi_smi_info smi_data;
455         acpi_handle handle;
456
457         err = ipmi_get_smi_info(iface, &smi_data);
458         if (err)
459                 return;
460
461         if (smi_data.addr_src != SI_ACPI)
462                 goto err_ref;
463         handle = smi_data.addr_info.acpi_info.acpi_handle;
464         if (!handle)
465                 goto err_ref;
466
467         ipmi_device = ipmi_dev_alloc(iface, smi_data.dev, handle);
468         if (!ipmi_device) {
469                 dev_warn(smi_data.dev, "Can't create IPMI user interface\n");
470                 goto err_ref;
471         }
472
473         mutex_lock(&driver_data.ipmi_lock);
474         list_for_each_entry(temp, &driver_data.ipmi_devices, head) {
475                 /*
476                  * if the corresponding ACPI handle is already added
477                  * to the device list, don't add it again.
478                  */
479                 if (temp->handle == handle)
480                         goto err_lock;
481         }
482         if (!driver_data.selected_smi)
483                 driver_data.selected_smi = ipmi_device;
484         list_add_tail(&ipmi_device->head, &driver_data.ipmi_devices);
485         mutex_unlock(&driver_data.ipmi_lock);
486
487         put_device(smi_data.dev);
488         return;
489
490 err_lock:
491         mutex_unlock(&driver_data.ipmi_lock);
492         ipmi_dev_release(ipmi_device);
493 err_ref:
494         put_device(smi_data.dev);
495         return;
496 }
497
498 static void ipmi_bmc_gone(int iface)
499 {
500         struct acpi_ipmi_device *ipmi_device, *temp;
501         bool dev_found = false;
502
503         mutex_lock(&driver_data.ipmi_lock);
504         list_for_each_entry_safe(ipmi_device, temp,
505                                  &driver_data.ipmi_devices, head) {
506                 if (ipmi_device->ipmi_ifnum != iface) {
507                         dev_found = true;
508                         __ipmi_dev_kill(ipmi_device);
509                         break;
510                 }
511         }
512         if (!driver_data.selected_smi)
513                 driver_data.selected_smi = list_first_entry_or_null(
514                                         &driver_data.ipmi_devices,
515                                         struct acpi_ipmi_device, head);
516         mutex_unlock(&driver_data.ipmi_lock);
517
518         if (dev_found) {
519                 ipmi_flush_tx_msg(ipmi_device);
520                 acpi_ipmi_dev_put(ipmi_device);
521         }
522 }
523
524 /*
525  * This is the IPMI opregion space handler.
526  * @function: indicates the read/write. In fact as the IPMI message is driven
527  * by command, only write is meaningful.
528  * @address: This contains the netfn/command of IPMI request message.
529  * @bits   : not used.
530  * @value  : it is an in/out parameter. It points to the IPMI message buffer.
531  *           Before the IPMI message is sent, it represents the actual request
532  *           IPMI message. After the IPMI message is finished, it represents
533  *           the response IPMI message returned by IPMI command.
534  * @handler_context: IPMI device context.
535  */
536 static acpi_status
537 acpi_ipmi_space_handler(u32 function, acpi_physical_address address,
538                         u32 bits, acpi_integer *value,
539                         void *handler_context, void *region_context)
540 {
541         struct acpi_ipmi_msg *tx_msg;
542         struct acpi_ipmi_device *ipmi_device;
543         int err;
544         acpi_status status;
545         unsigned long flags;
546
547         /*
548          * IPMI opregion message.
549          * IPMI message is firstly written to the BMC and system software
550          * can get the respsonse. So it is unmeaningful for the read access
551          * of IPMI opregion.
552          */
553         if ((function & ACPI_IO_MASK) == ACPI_READ)
554                 return AE_TYPE;
555
556         tx_msg = ipmi_msg_alloc();
557         if (!tx_msg)
558                 return AE_NOT_EXIST;
559         ipmi_device = tx_msg->device;
560
561         if (acpi_format_ipmi_request(tx_msg, address, value) != 0) {
562                 ipmi_msg_release(tx_msg);
563                 return AE_TYPE;
564         }
565
566         acpi_ipmi_msg_get(tx_msg);
567         mutex_lock(&driver_data.ipmi_lock);
568         /* Do not add a tx_msg that can not be flushed. */
569         if (ipmi_device->dead) {
570                 mutex_unlock(&driver_data.ipmi_lock);
571                 ipmi_msg_release(tx_msg);
572                 return AE_NOT_EXIST;
573         }
574         spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
575         list_add_tail(&tx_msg->head, &ipmi_device->tx_msg_list);
576         spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
577         mutex_unlock(&driver_data.ipmi_lock);
578
579         err = ipmi_request_settime(ipmi_device->user_interface,
580                                    &tx_msg->addr,
581                                    tx_msg->tx_msgid,
582                                    &tx_msg->tx_message,
583                                    NULL, 0, 0, IPMI_TIMEOUT);
584         if (err) {
585                 status = AE_ERROR;
586                 goto out_msg;
587         }
588         wait_for_completion(&tx_msg->tx_complete);
589
590         acpi_format_ipmi_response(tx_msg, value);
591         status = AE_OK;
592
593 out_msg:
594         ipmi_cancel_tx_msg(ipmi_device, tx_msg);
595         acpi_ipmi_msg_put(tx_msg);
596         return status;
597 }
598
599 static int __init acpi_ipmi_init(void)
600 {
601         int result;
602         acpi_status status;
603
604         if (acpi_disabled)
605                 return 0;
606
607         status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
608                                                     ACPI_ADR_SPACE_IPMI,
609                                                     &acpi_ipmi_space_handler,
610                                                     NULL, NULL);
611         if (ACPI_FAILURE(status)) {
612                 pr_warn("Can't register IPMI opregion space handle\n");
613                 return -EINVAL;
614         }
615         result = ipmi_smi_watcher_register(&driver_data.bmc_events);
616         if (result)
617                 pr_err("Can't register IPMI system interface watcher\n");
618
619         return result;
620 }
621
622 static void __exit acpi_ipmi_exit(void)
623 {
624         struct acpi_ipmi_device *ipmi_device;
625
626         if (acpi_disabled)
627                 return;
628
629         ipmi_smi_watcher_unregister(&driver_data.bmc_events);
630
631         /*
632          * When one smi_watcher is unregistered, it is only deleted
633          * from the smi_watcher list. But the smi_gone callback function
634          * is not called. So explicitly uninstall the ACPI IPMI oregion
635          * handler and free it.
636          */
637         mutex_lock(&driver_data.ipmi_lock);
638         while (!list_empty(&driver_data.ipmi_devices)) {
639                 ipmi_device = list_first_entry(&driver_data.ipmi_devices,
640                                                struct acpi_ipmi_device,
641                                                head);
642                 __ipmi_dev_kill(ipmi_device);
643                 mutex_unlock(&driver_data.ipmi_lock);
644
645                 ipmi_flush_tx_msg(ipmi_device);
646                 acpi_ipmi_dev_put(ipmi_device);
647
648                 mutex_lock(&driver_data.ipmi_lock);
649         }
650         mutex_unlock(&driver_data.ipmi_lock);
651         acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
652                                           ACPI_ADR_SPACE_IPMI,
653                                           &acpi_ipmi_space_handler);
654 }
655
656 module_init(acpi_ipmi_init);
657 module_exit(acpi_ipmi_exit);