1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * acpi_ipmi.c - ACPI IPMI opregion
4 *
5 * Copyright (C) 2010, 2013 Intel Corporation
6 * Author: Zhao Yakui <yakui.zhao@intel.com>
7 * Lv Zheng <lv.zheng@intel.com>
8 */
9
10 #include <linux/module.h>
11 #include <linux/acpi.h>
12 #include <linux/ipmi.h>
13 #include <linux/spinlock.h>
14
15 MODULE_AUTHOR("Zhao Yakui");
16 MODULE_DESCRIPTION("ACPI IPMI Opregion driver");
17 MODULE_LICENSE("GPL");
18
19 #define ACPI_IPMI_OK 0
20 #define ACPI_IPMI_TIMEOUT 0x10
21 #define ACPI_IPMI_UNKNOWN 0x07
22 /* the IPMI timeout is 5s */
23 #define IPMI_TIMEOUT (5000)
24 #define ACPI_IPMI_MAX_MSG_LENGTH 64
25 /* 2s should be suffient for SMI being selected */
26 #define ACPI_IPMI_SMI_SELECTION_TIMEOUT (2 * HZ)
27
28 struct acpi_ipmi_device {
29 /* the device list attached to driver_data.ipmi_devices */
30 struct list_head head;
31
32 /* the IPMI request message list */
33 struct list_head tx_msg_list;
34
35 spinlock_t tx_msg_lock;
36 acpi_handle handle;
37 struct device *dev;
38 struct ipmi_user *user_interface;
39 int ipmi_ifnum; /* IPMI interface number */
40 long curr_msgid;
41 bool dead;
42 struct kref kref;
43 };
44
45 struct ipmi_driver_data {
46 struct list_head ipmi_devices;
47 struct ipmi_smi_watcher bmc_events;
48 const struct ipmi_user_hndl ipmi_hndlrs;
49 struct mutex ipmi_lock;
50
51 /*
52 * NOTE: IPMI System Interface Selection
53 * There is no system interface specified by the IPMI operation
54 * region access. We try to select one system interface with ACPI
55 * handle set. IPMI messages passed from the ACPI codes are sent
56 * to this selected global IPMI system interface.
57 */
58 struct acpi_ipmi_device *selected_smi;
59 struct completion smi_selection_done;
60 };
61
62 struct acpi_ipmi_msg {
63 struct list_head head;
64
65 /*
66 * General speaking the addr type should be SI_ADDR_TYPE. And
67 * the addr channel should be BMC.
68 * In fact it can also be IPMB type. But we will have to
69 * parse it from the Netfn command buffer. It is so complex
70 * that it is skipped.
71 */
72 struct ipmi_addr addr;
73 long tx_msgid;
74
75 /* it is used to track whether the IPMI message is finished */
76 struct completion tx_complete;
77
78 struct kernel_ipmi_msg tx_message;
79 int msg_done;
80
81 /* tx/rx data . And copy it from/to ACPI object buffer */
82 u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
83 u8 rx_len;
84
85 struct acpi_ipmi_device *device;
86 struct kref kref;
87 };
88
89 /* IPMI request/response buffer per ACPI 4.0, sec 5.5.2.4.3.2 */
90 struct acpi_ipmi_buffer {
91 u8 status;
92 u8 length;
93 u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
94 };
95
96 static void ipmi_register_bmc(int iface, struct device *dev);
97 static void ipmi_bmc_gone(int iface);
98 static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);
99
100 static struct ipmi_driver_data driver_data = {
101 .ipmi_devices = LIST_HEAD_INIT(driver_data.ipmi_devices),
102 .bmc_events = {
103 .owner = THIS_MODULE,
104 .new_smi = ipmi_register_bmc,
105 .smi_gone = ipmi_bmc_gone,
106 },
107 .ipmi_hndlrs = {
108 .ipmi_recv_hndl = ipmi_msg_handler,
109 },
110 .ipmi_lock = __MUTEX_INITIALIZER(driver_data.ipmi_lock)
111 };
112
113 static struct acpi_ipmi_device *
ipmi_dev_alloc(int iface,struct device * dev,acpi_handle handle)114 ipmi_dev_alloc(int iface, struct device *dev, acpi_handle handle)
115 {
116 struct acpi_ipmi_device *ipmi_device;
117 int err;
118 struct ipmi_user *user;
119
120 ipmi_device = kzalloc(sizeof(*ipmi_device), GFP_KERNEL);
121 if (!ipmi_device)
122 return NULL;
123
124 kref_init(&ipmi_device->kref);
125 INIT_LIST_HEAD(&ipmi_device->head);
126 INIT_LIST_HEAD(&ipmi_device->tx_msg_list);
127 spin_lock_init(&ipmi_device->tx_msg_lock);
128 ipmi_device->handle = handle;
129 ipmi_device->dev = get_device(dev);
130 ipmi_device->ipmi_ifnum = iface;
131
132 err = ipmi_create_user(iface, &driver_data.ipmi_hndlrs,
133 ipmi_device, &user);
134 if (err) {
135 put_device(dev);
136 kfree(ipmi_device);
137 return NULL;
138 }
139 ipmi_device->user_interface = user;
140
141 return ipmi_device;
142 }
143
ipmi_dev_release(struct acpi_ipmi_device * ipmi_device)144 static void ipmi_dev_release(struct acpi_ipmi_device *ipmi_device)
145 {
146 ipmi_destroy_user(ipmi_device->user_interface);
147 put_device(ipmi_device->dev);
148 kfree(ipmi_device);
149 }
150
ipmi_dev_release_kref(struct kref * kref)151 static void ipmi_dev_release_kref(struct kref *kref)
152 {
153 struct acpi_ipmi_device *ipmi =
154 container_of(kref, struct acpi_ipmi_device, kref);
155
156 ipmi_dev_release(ipmi);
157 }
158
__ipmi_dev_kill(struct acpi_ipmi_device * ipmi_device)159 static void __ipmi_dev_kill(struct acpi_ipmi_device *ipmi_device)
160 {
161 list_del(&ipmi_device->head);
162 if (driver_data.selected_smi == ipmi_device)
163 driver_data.selected_smi = NULL;
164
165 /*
166 * Always setting dead flag after deleting from the list or
167 * list_for_each_entry() codes must get changed.
168 */
169 ipmi_device->dead = true;
170 }
171
acpi_ipmi_dev_get(void)172 static struct acpi_ipmi_device *acpi_ipmi_dev_get(void)
173 {
174 struct acpi_ipmi_device *ipmi_device = NULL;
175
176 mutex_lock(&driver_data.ipmi_lock);
177 if (driver_data.selected_smi) {
178 ipmi_device = driver_data.selected_smi;
179 kref_get(&ipmi_device->kref);
180 }
181 mutex_unlock(&driver_data.ipmi_lock);
182
183 return ipmi_device;
184 }
185
acpi_ipmi_dev_put(struct acpi_ipmi_device * ipmi_device)186 static void acpi_ipmi_dev_put(struct acpi_ipmi_device *ipmi_device)
187 {
188 kref_put(&ipmi_device->kref, ipmi_dev_release_kref);
189 }
190
ipmi_msg_alloc(void)191 static struct acpi_ipmi_msg *ipmi_msg_alloc(void)
192 {
193 struct acpi_ipmi_device *ipmi;
194 struct acpi_ipmi_msg *ipmi_msg;
195
196 ipmi = acpi_ipmi_dev_get();
197 if (!ipmi)
198 return NULL;
199
200 ipmi_msg = kzalloc(sizeof(struct acpi_ipmi_msg), GFP_KERNEL);
201 if (!ipmi_msg) {
202 acpi_ipmi_dev_put(ipmi);
203 return NULL;
204 }
205
206 kref_init(&ipmi_msg->kref);
207 init_completion(&ipmi_msg->tx_complete);
208 INIT_LIST_HEAD(&ipmi_msg->head);
209 ipmi_msg->device = ipmi;
210 ipmi_msg->msg_done = ACPI_IPMI_UNKNOWN;
211
212 return ipmi_msg;
213 }
214
ipmi_msg_release(struct acpi_ipmi_msg * tx_msg)215 static void ipmi_msg_release(struct acpi_ipmi_msg *tx_msg)
216 {
217 acpi_ipmi_dev_put(tx_msg->device);
218 kfree(tx_msg);
219 }
220
ipmi_msg_release_kref(struct kref * kref)221 static void ipmi_msg_release_kref(struct kref *kref)
222 {
223 struct acpi_ipmi_msg *tx_msg =
224 container_of(kref, struct acpi_ipmi_msg, kref);
225
226 ipmi_msg_release(tx_msg);
227 }
228
acpi_ipmi_msg_get(struct acpi_ipmi_msg * tx_msg)229 static struct acpi_ipmi_msg *acpi_ipmi_msg_get(struct acpi_ipmi_msg *tx_msg)
230 {
231 kref_get(&tx_msg->kref);
232
233 return tx_msg;
234 }
235
acpi_ipmi_msg_put(struct acpi_ipmi_msg * tx_msg)236 static void acpi_ipmi_msg_put(struct acpi_ipmi_msg *tx_msg)
237 {
238 kref_put(&tx_msg->kref, ipmi_msg_release_kref);
239 }
240
241 #define IPMI_OP_RGN_NETFN(offset) ((offset >> 8) & 0xff)
242 #define IPMI_OP_RGN_CMD(offset) (offset & 0xff)
acpi_format_ipmi_request(struct acpi_ipmi_msg * tx_msg,acpi_physical_address address,acpi_integer * value)243 static int acpi_format_ipmi_request(struct acpi_ipmi_msg *tx_msg,
244 acpi_physical_address address,
245 acpi_integer *value)
246 {
247 struct kernel_ipmi_msg *msg;
248 struct acpi_ipmi_buffer *buffer;
249 struct acpi_ipmi_device *device;
250 unsigned long flags;
251
252 msg = &tx_msg->tx_message;
253
254 /*
255 * IPMI network function and command are encoded in the address
256 * within the IPMI OpRegion; see ACPI 4.0, sec 5.5.2.4.3.
257 */
258 msg->netfn = IPMI_OP_RGN_NETFN(address);
259 msg->cmd = IPMI_OP_RGN_CMD(address);
260 msg->data = tx_msg->data;
261
262 /*
263 * value is the parameter passed by the IPMI opregion space handler.
264 * It points to the IPMI request message buffer
265 */
266 buffer = (struct acpi_ipmi_buffer *)value;
267
268 /* copy the tx message data */
269 if (buffer->length > ACPI_IPMI_MAX_MSG_LENGTH) {
270 dev_WARN_ONCE(tx_msg->device->dev, true,
271 "Unexpected request (msg len %d).\n",
272 buffer->length);
273 return -EINVAL;
274 }
275 msg->data_len = buffer->length;
276 memcpy(tx_msg->data, buffer->data, msg->data_len);
277
278 /*
279 * now the default type is SYSTEM_INTERFACE and channel type is BMC.
280 * If the netfn is APP_REQUEST and the cmd is SEND_MESSAGE,
281 * the addr type should be changed to IPMB. Then we will have to parse
282 * the IPMI request message buffer to get the IPMB address.
283 * If so, please fix me.
284 */
285 tx_msg->addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
286 tx_msg->addr.channel = IPMI_BMC_CHANNEL;
287 tx_msg->addr.data[0] = 0;
288
289 /* Get the msgid */
290 device = tx_msg->device;
291
292 spin_lock_irqsave(&device->tx_msg_lock, flags);
293 device->curr_msgid++;
294 tx_msg->tx_msgid = device->curr_msgid;
295 spin_unlock_irqrestore(&device->tx_msg_lock, flags);
296
297 return 0;
298 }
299
acpi_format_ipmi_response(struct acpi_ipmi_msg * msg,acpi_integer * value)300 static void acpi_format_ipmi_response(struct acpi_ipmi_msg *msg,
301 acpi_integer *value)
302 {
303 struct acpi_ipmi_buffer *buffer;
304
305 /*
306 * value is also used as output parameter. It represents the response
307 * IPMI message returned by IPMI command.
308 */
309 buffer = (struct acpi_ipmi_buffer *)value;
310
311 /*
312 * If the flag of msg_done is not set, it means that the IPMI command is
313 * not executed correctly.
314 */
315 buffer->status = msg->msg_done;
316 if (msg->msg_done != ACPI_IPMI_OK)
317 return;
318
319 /*
320 * If the IPMI response message is obtained correctly, the status code
321 * will be ACPI_IPMI_OK
322 */
323 buffer->length = msg->rx_len;
324 memcpy(buffer->data, msg->data, msg->rx_len);
325 }
326
ipmi_flush_tx_msg(struct acpi_ipmi_device * ipmi)327 static void ipmi_flush_tx_msg(struct acpi_ipmi_device *ipmi)
328 {
329 struct acpi_ipmi_msg *tx_msg;
330 unsigned long flags;
331
332 /*
333 * NOTE: On-going ipmi_recv_msg
334 * ipmi_msg_handler() may still be invoked by ipmi_si after
335 * flushing. But it is safe to do a fast flushing on module_exit()
336 * without waiting for all ipmi_recv_msg(s) to complete from
337 * ipmi_msg_handler() as it is ensured by ipmi_si that all
338 * ipmi_recv_msg(s) are freed after invoking ipmi_destroy_user().
339 */
340 spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
341 while (!list_empty(&ipmi->tx_msg_list)) {
342 tx_msg = list_first_entry(&ipmi->tx_msg_list,
343 struct acpi_ipmi_msg,
344 head);
345 list_del(&tx_msg->head);
346 spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
347
348 /* wake up the sleep thread on the Tx msg */
349 complete(&tx_msg->tx_complete);
350 acpi_ipmi_msg_put(tx_msg);
351 spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
352 }
353 spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
354 }
355
ipmi_cancel_tx_msg(struct acpi_ipmi_device * ipmi,struct acpi_ipmi_msg * msg)356 static void ipmi_cancel_tx_msg(struct acpi_ipmi_device *ipmi,
357 struct acpi_ipmi_msg *msg)
358 {
359 struct acpi_ipmi_msg *tx_msg = NULL, *iter, *temp;
360 unsigned long flags;
361
362 spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
363 list_for_each_entry_safe(iter, temp, &ipmi->tx_msg_list, head) {
364 if (msg == iter) {
365 tx_msg = iter;
366 list_del(&iter->head);
367 break;
368 }
369 }
370 spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
371
372 if (tx_msg)
373 acpi_ipmi_msg_put(tx_msg);
374 }
375
ipmi_msg_handler(struct ipmi_recv_msg * msg,void * user_msg_data)376 static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data)
377 {
378 struct acpi_ipmi_device *ipmi_device = user_msg_data;
379 struct acpi_ipmi_msg *tx_msg = NULL, *iter, *temp;
380 struct device *dev = ipmi_device->dev;
381 unsigned long flags;
382
383 if (msg->user != ipmi_device->user_interface) {
384 dev_warn(dev,
385 "Unexpected response is returned. returned user %p, expected user %p\n",
386 msg->user, ipmi_device->user_interface);
387 goto out_msg;
388 }
389
390 spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
391 list_for_each_entry_safe(iter, temp, &ipmi_device->tx_msg_list, head) {
392 if (msg->msgid == iter->tx_msgid) {
393 tx_msg = iter;
394 list_del(&iter->head);
395 break;
396 }
397 }
398 spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
399
400 if (!tx_msg) {
401 dev_warn(dev,
402 "Unexpected response (msg id %ld) is returned.\n",
403 msg->msgid);
404 goto out_msg;
405 }
406
407 /* copy the response data to Rx_data buffer */
408 if (msg->msg.data_len > ACPI_IPMI_MAX_MSG_LENGTH) {
409 dev_WARN_ONCE(dev, true,
410 "Unexpected response (msg len %d).\n",
411 msg->msg.data_len);
412 goto out_comp;
413 }
414
415 /* response msg is an error msg */
416 msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
417 if (msg->recv_type == IPMI_RESPONSE_RECV_TYPE &&
418 msg->msg.data_len == 1) {
419 if (msg->msg.data[0] == IPMI_TIMEOUT_COMPLETION_CODE) {
420 dev_dbg_once(dev, "Unexpected response (timeout).\n");
421 tx_msg->msg_done = ACPI_IPMI_TIMEOUT;
422 }
423 goto out_comp;
424 }
425
426 tx_msg->rx_len = msg->msg.data_len;
427 memcpy(tx_msg->data, msg->msg.data, tx_msg->rx_len);
428 tx_msg->msg_done = ACPI_IPMI_OK;
429
430 out_comp:
431 complete(&tx_msg->tx_complete);
432 acpi_ipmi_msg_put(tx_msg);
433 out_msg:
434 ipmi_free_recv_msg(msg);
435 }
436
ipmi_register_bmc(int iface,struct device * dev)437 static void ipmi_register_bmc(int iface, struct device *dev)
438 {
439 struct acpi_ipmi_device *ipmi_device, *temp;
440 int err;
441 struct ipmi_smi_info smi_data;
442 acpi_handle handle;
443
444 err = ipmi_get_smi_info(iface, &smi_data);
445 if (err)
446 return;
447
448 if (smi_data.addr_src != SI_ACPI)
449 goto err_ref;
450 handle = smi_data.addr_info.acpi_info.acpi_handle;
451 if (!handle)
452 goto err_ref;
453
454 ipmi_device = ipmi_dev_alloc(iface, smi_data.dev, handle);
455 if (!ipmi_device) {
456 dev_warn(smi_data.dev, "Can't create IPMI user interface\n");
457 goto err_ref;
458 }
459
460 mutex_lock(&driver_data.ipmi_lock);
461 list_for_each_entry(temp, &driver_data.ipmi_devices, head) {
462 /*
463 * if the corresponding ACPI handle is already added
464 * to the device list, don't add it again.
465 */
466 if (temp->handle == handle)
467 goto err_lock;
468 }
469 if (!driver_data.selected_smi) {
470 driver_data.selected_smi = ipmi_device;
471 complete(&driver_data.smi_selection_done);
472 }
473 list_add_tail(&ipmi_device->head, &driver_data.ipmi_devices);
474 mutex_unlock(&driver_data.ipmi_lock);
475
476 put_device(smi_data.dev);
477 return;
478
479 err_lock:
480 mutex_unlock(&driver_data.ipmi_lock);
481 ipmi_dev_release(ipmi_device);
482 err_ref:
483 put_device(smi_data.dev);
484 }
485
ipmi_bmc_gone(int iface)486 static void ipmi_bmc_gone(int iface)
487 {
488 struct acpi_ipmi_device *ipmi_device = NULL, *iter, *temp;
489
490 mutex_lock(&driver_data.ipmi_lock);
491 list_for_each_entry_safe(iter, temp,
492 &driver_data.ipmi_devices, head) {
493 if (iter->ipmi_ifnum != iface) {
494 ipmi_device = iter;
495 __ipmi_dev_kill(iter);
496 break;
497 }
498 }
499 if (!driver_data.selected_smi)
500 driver_data.selected_smi = list_first_entry_or_null(
501 &driver_data.ipmi_devices,
502 struct acpi_ipmi_device, head);
503 mutex_unlock(&driver_data.ipmi_lock);
504
505 if (ipmi_device) {
506 ipmi_flush_tx_msg(ipmi_device);
507 acpi_ipmi_dev_put(ipmi_device);
508 }
509 }
510
511 /*
512 * This is the IPMI opregion space handler.
513 * @function: indicates the read/write. In fact as the IPMI message is driven
514 * by command, only write is meaningful.
515 * @address: This contains the netfn/command of IPMI request message.
516 * @bits : not used.
517 * @value : it is an in/out parameter. It points to the IPMI message buffer.
518 * Before the IPMI message is sent, it represents the actual request
519 * IPMI message. After the IPMI message is finished, it represents
520 * the response IPMI message returned by IPMI command.
521 * @handler_context: IPMI device context.
522 */
523 static acpi_status
acpi_ipmi_space_handler(u32 function,acpi_physical_address address,u32 bits,acpi_integer * value,void * handler_context,void * region_context)524 acpi_ipmi_space_handler(u32 function, acpi_physical_address address,
525 u32 bits, acpi_integer *value,
526 void *handler_context, void *region_context)
527 {
528 struct acpi_ipmi_msg *tx_msg;
529 struct acpi_ipmi_device *ipmi_device;
530 int err;
531 acpi_status status;
532 unsigned long flags;
533
534 /*
535 * IPMI opregion message.
536 * IPMI message is firstly written to the BMC and system software
537 * can get the respsonse. So it is unmeaningful for the read access
538 * of IPMI opregion.
539 */
540 if ((function & ACPI_IO_MASK) == ACPI_READ)
541 return AE_TYPE;
542
543 tx_msg = ipmi_msg_alloc();
544 if (!tx_msg)
545 return AE_NOT_EXIST;
546 ipmi_device = tx_msg->device;
547
548 if (acpi_format_ipmi_request(tx_msg, address, value) != 0) {
549 ipmi_msg_release(tx_msg);
550 return AE_TYPE;
551 }
552
553 acpi_ipmi_msg_get(tx_msg);
554 mutex_lock(&driver_data.ipmi_lock);
555 /* Do not add a tx_msg that can not be flushed. */
556 if (ipmi_device->dead) {
557 mutex_unlock(&driver_data.ipmi_lock);
558 ipmi_msg_release(tx_msg);
559 return AE_NOT_EXIST;
560 }
561 spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
562 list_add_tail(&tx_msg->head, &ipmi_device->tx_msg_list);
563 spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
564 mutex_unlock(&driver_data.ipmi_lock);
565
566 err = ipmi_request_settime(ipmi_device->user_interface,
567 &tx_msg->addr,
568 tx_msg->tx_msgid,
569 &tx_msg->tx_message,
570 NULL, 0, 0, IPMI_TIMEOUT);
571 if (err) {
572 status = AE_ERROR;
573 goto out_msg;
574 }
575 wait_for_completion(&tx_msg->tx_complete);
576
577 acpi_format_ipmi_response(tx_msg, value);
578 status = AE_OK;
579
580 out_msg:
581 ipmi_cancel_tx_msg(ipmi_device, tx_msg);
582 acpi_ipmi_msg_put(tx_msg);
583 return status;
584 }
585
acpi_wait_for_acpi_ipmi(void)586 int acpi_wait_for_acpi_ipmi(void)
587 {
588 long ret;
589
590 ret = wait_for_completion_interruptible_timeout(&driver_data.smi_selection_done,
591 ACPI_IPMI_SMI_SELECTION_TIMEOUT);
592
593 if (ret <= 0)
594 return -ETIMEDOUT;
595
596 return 0;
597 }
598 EXPORT_SYMBOL_GPL(acpi_wait_for_acpi_ipmi);
599
acpi_ipmi_init(void)600 static int __init acpi_ipmi_init(void)
601 {
602 int result;
603 acpi_status status;
604
605 if (acpi_disabled)
606 return 0;
607
608 init_completion(&driver_data.smi_selection_done);
609
610 status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
611 ACPI_ADR_SPACE_IPMI,
612 &acpi_ipmi_space_handler,
613 NULL, NULL);
614 if (ACPI_FAILURE(status)) {
615 pr_warn("Can't register IPMI opregion space handle\n");
616 return -EINVAL;
617 }
618
619 result = ipmi_smi_watcher_register(&driver_data.bmc_events);
620 if (result) {
621 acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
622 ACPI_ADR_SPACE_IPMI,
623 &acpi_ipmi_space_handler);
624 pr_err("Can't register IPMI system interface watcher\n");
625 }
626
627 return result;
628 }
629
acpi_ipmi_exit(void)630 static void __exit acpi_ipmi_exit(void)
631 {
632 struct acpi_ipmi_device *ipmi_device;
633
634 if (acpi_disabled)
635 return;
636
637 ipmi_smi_watcher_unregister(&driver_data.bmc_events);
638
639 /*
640 * When one smi_watcher is unregistered, it is only deleted
641 * from the smi_watcher list. But the smi_gone callback function
642 * is not called. So explicitly uninstall the ACPI IPMI oregion
643 * handler and free it.
644 */
645 mutex_lock(&driver_data.ipmi_lock);
646 while (!list_empty(&driver_data.ipmi_devices)) {
647 ipmi_device = list_first_entry(&driver_data.ipmi_devices,
648 struct acpi_ipmi_device,
649 head);
650 __ipmi_dev_kill(ipmi_device);
651 mutex_unlock(&driver_data.ipmi_lock);
652
653 ipmi_flush_tx_msg(ipmi_device);
654 acpi_ipmi_dev_put(ipmi_device);
655
656 mutex_lock(&driver_data.ipmi_lock);
657 }
658 mutex_unlock(&driver_data.ipmi_lock);
659 acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
660 ACPI_ADR_SPACE_IPMI,
661 &acpi_ipmi_space_handler);
662 }
663
664 module_init(acpi_ipmi_init);
665 module_exit(acpi_ipmi_exit);
666