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
28MODULE_AUTHOR("Zhao Yakui");
29MODULE_DESCRIPTION("ACPI IPMI Opregion driver");
30MODULE_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
39struct 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 struct ipmi_user *user_interface;
50 int ipmi_ifnum; /* IPMI interface number */
51 long curr_msgid;
52 bool dead;
53 struct kref kref;
54};
55
56struct ipmi_driver_data {
57 struct list_head ipmi_devices;
58 struct ipmi_smi_watcher bmc_events;
59 const 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
72struct 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 */
100struct acpi_ipmi_buffer {
101 u8 status;
102 u8 length;
103 u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
104};
105
106static void ipmi_register_bmc(int iface, struct device *dev);
107static void ipmi_bmc_gone(int iface);
108static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);
109
110static 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
123static struct acpi_ipmi_device *
124ipmi_dev_alloc(int iface, struct device *dev, acpi_handle handle)
125{
126 struct acpi_ipmi_device *ipmi_device;
127 int err;
128 struct ipmi_user *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
154static 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
161static 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
169static 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
182static 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
196static void acpi_ipmi_dev_put(struct acpi_ipmi_device *ipmi_device)
197{
198 kref_put(&ipmi_device->kref, ipmi_dev_release_kref);
199}
200
201static 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
225static 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
231static 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
239static 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
246static 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)
253static 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
310static 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
337static 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
366static 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
387static 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_dbg_once(dev, "Unexpected response (timeout).\n");
433 tx_msg->msg_done = ACPI_IPMI_TIMEOUT;
434 }
435 goto out_comp;
436 }
437
438 tx_msg->rx_len = msg->msg.data_len;
439 memcpy(tx_msg->data, msg->msg.data, tx_msg->rx_len);
440 tx_msg->msg_done = ACPI_IPMI_OK;
441
442out_comp:
443 complete(&tx_msg->tx_complete);
444 acpi_ipmi_msg_put(tx_msg);
445out_msg:
446 ipmi_free_recv_msg(msg);
447}
448
449static void ipmi_register_bmc(int iface, struct device *dev)
450{
451 struct acpi_ipmi_device *ipmi_device, *temp;
452 int err;
453 struct ipmi_smi_info smi_data;
454 acpi_handle handle;
455
456 err = ipmi_get_smi_info(iface, &smi_data);
457 if (err)
458 return;
459
460 if (smi_data.addr_src != SI_ACPI)
461 goto err_ref;
462 handle = smi_data.addr_info.acpi_info.acpi_handle;
463 if (!handle)
464 goto err_ref;
465
466 ipmi_device = ipmi_dev_alloc(iface, smi_data.dev, handle);
467 if (!ipmi_device) {
468 dev_warn(smi_data.dev, "Can't create IPMI user interface\n");
469 goto err_ref;
470 }
471
472 mutex_lock(&driver_data.ipmi_lock);
473 list_for_each_entry(temp, &driver_data.ipmi_devices, head) {
474 /*
475 * if the corresponding ACPI handle is already added
476 * to the device list, don't add it again.
477 */
478 if (temp->handle == handle)
479 goto err_lock;
480 }
481 if (!driver_data.selected_smi)
482 driver_data.selected_smi = ipmi_device;
483 list_add_tail(&ipmi_device->head, &driver_data.ipmi_devices);
484 mutex_unlock(&driver_data.ipmi_lock);
485
486 put_device(smi_data.dev);
487 return;
488
489err_lock:
490 mutex_unlock(&driver_data.ipmi_lock);
491 ipmi_dev_release(ipmi_device);
492err_ref:
493 put_device(smi_data.dev);
494 return;
495}
496
497static void ipmi_bmc_gone(int iface)
498{
499 struct acpi_ipmi_device *ipmi_device, *temp;
500 bool dev_found = false;
501
502 mutex_lock(&driver_data.ipmi_lock);
503 list_for_each_entry_safe(ipmi_device, temp,
504 &driver_data.ipmi_devices, head) {
505 if (ipmi_device->ipmi_ifnum != iface) {
506 dev_found = true;
507 __ipmi_dev_kill(ipmi_device);
508 break;
509 }
510 }
511 if (!driver_data.selected_smi)
512 driver_data.selected_smi = list_first_entry_or_null(
513 &driver_data.ipmi_devices,
514 struct acpi_ipmi_device, head);
515 mutex_unlock(&driver_data.ipmi_lock);
516
517 if (dev_found) {
518 ipmi_flush_tx_msg(ipmi_device);
519 acpi_ipmi_dev_put(ipmi_device);
520 }
521}
522
523/*
524 * This is the IPMI opregion space handler.
525 * @function: indicates the read/write. In fact as the IPMI message is driven
526 * by command, only write is meaningful.
527 * @address: This contains the netfn/command of IPMI request message.
528 * @bits : not used.
529 * @value : it is an in/out parameter. It points to the IPMI message buffer.
530 * Before the IPMI message is sent, it represents the actual request
531 * IPMI message. After the IPMI message is finished, it represents
532 * the response IPMI message returned by IPMI command.
533 * @handler_context: IPMI device context.
534 */
535static acpi_status
536acpi_ipmi_space_handler(u32 function, acpi_physical_address address,
537 u32 bits, acpi_integer *value,
538 void *handler_context, void *region_context)
539{
540 struct acpi_ipmi_msg *tx_msg;
541 struct acpi_ipmi_device *ipmi_device;
542 int err;
543 acpi_status status;
544 unsigned long flags;
545
546 /*
547 * IPMI opregion message.
548 * IPMI message is firstly written to the BMC and system software
549 * can get the respsonse. So it is unmeaningful for the read access
550 * of IPMI opregion.
551 */
552 if ((function & ACPI_IO_MASK) == ACPI_READ)
553 return AE_TYPE;
554
555 tx_msg = ipmi_msg_alloc();
556 if (!tx_msg)
557 return AE_NOT_EXIST;
558 ipmi_device = tx_msg->device;
559
560 if (acpi_format_ipmi_request(tx_msg, address, value) != 0) {
561 ipmi_msg_release(tx_msg);
562 return AE_TYPE;
563 }
564
565 acpi_ipmi_msg_get(tx_msg);
566 mutex_lock(&driver_data.ipmi_lock);
567 /* Do not add a tx_msg that can not be flushed. */
568 if (ipmi_device->dead) {
569 mutex_unlock(&driver_data.ipmi_lock);
570 ipmi_msg_release(tx_msg);
571 return AE_NOT_EXIST;
572 }
573 spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
574 list_add_tail(&tx_msg->head, &ipmi_device->tx_msg_list);
575 spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
576 mutex_unlock(&driver_data.ipmi_lock);
577
578 err = ipmi_request_settime(ipmi_device->user_interface,
579 &tx_msg->addr,
580 tx_msg->tx_msgid,
581 &tx_msg->tx_message,
582 NULL, 0, 0, IPMI_TIMEOUT);
583 if (err) {
584 status = AE_ERROR;
585 goto out_msg;
586 }
587 wait_for_completion(&tx_msg->tx_complete);
588
589 acpi_format_ipmi_response(tx_msg, value);
590 status = AE_OK;
591
592out_msg:
593 ipmi_cancel_tx_msg(ipmi_device, tx_msg);
594 acpi_ipmi_msg_put(tx_msg);
595 return status;
596}
597
598static int __init acpi_ipmi_init(void)
599{
600 int result;
601 acpi_status status;
602
603 if (acpi_disabled)
604 return 0;
605
606 status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
607 ACPI_ADR_SPACE_IPMI,
608 &acpi_ipmi_space_handler,
609 NULL, NULL);
610 if (ACPI_FAILURE(status)) {
611 pr_warn("Can't register IPMI opregion space handle\n");
612 return -EINVAL;
613 }
614 result = ipmi_smi_watcher_register(&driver_data.bmc_events);
615 if (result)
616 pr_err("Can't register IPMI system interface watcher\n");
617
618 return result;
619}
620
621static void __exit acpi_ipmi_exit(void)
622{
623 struct acpi_ipmi_device *ipmi_device;
624
625 if (acpi_disabled)
626 return;
627
628 ipmi_smi_watcher_unregister(&driver_data.bmc_events);
629
630 /*
631 * When one smi_watcher is unregistered, it is only deleted
632 * from the smi_watcher list. But the smi_gone callback function
633 * is not called. So explicitly uninstall the ACPI IPMI oregion
634 * handler and free it.
635 */
636 mutex_lock(&driver_data.ipmi_lock);
637 while (!list_empty(&driver_data.ipmi_devices)) {
638 ipmi_device = list_first_entry(&driver_data.ipmi_devices,
639 struct acpi_ipmi_device,
640 head);
641 __ipmi_dev_kill(ipmi_device);
642 mutex_unlock(&driver_data.ipmi_lock);
643
644 ipmi_flush_tx_msg(ipmi_device);
645 acpi_ipmi_dev_put(ipmi_device);
646
647 mutex_lock(&driver_data.ipmi_lock);
648 }
649 mutex_unlock(&driver_data.ipmi_lock);
650 acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
651 ACPI_ADR_SPACE_IPMI,
652 &acpi_ipmi_space_handler);
653}
654
655module_init(acpi_ipmi_init);
656module_exit(acpi_ipmi_exit);
657