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