xref: /linux/drivers/misc/mei/client.c (revision 0a335b6d47f014c41b8a0c8cbdc6d4886c10f5d5)
1 /*
2  *
3  * Intel Management Engine Interface (Intel MEI) Linux driver
4  * Copyright (c) 2003-2012, Intel Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  *
15  */
16 
17 #include <linux/pci.h>
18 #include <linux/sched.h>
19 #include <linux/wait.h>
20 #include <linux/delay.h>
21 
22 #include <linux/mei.h>
23 
24 #include "mei_dev.h"
25 #include "hbm.h"
26 #include "client.h"
27 
28 /**
29  * mei_me_cl_by_uuid - locate index of me client
30  *
31  * @dev: mei device
32  * returns me client index or -ENOENT if not found
33  */
34 int mei_me_cl_by_uuid(const struct mei_device *dev, const uuid_le *uuid)
35 {
36 	int i, res = -ENOENT;
37 
38 	for (i = 0; i < dev->me_clients_num; ++i)
39 		if (uuid_le_cmp(*uuid,
40 				dev->me_clients[i].props.protocol_name) == 0) {
41 			res = i;
42 			break;
43 		}
44 
45 	return res;
46 }
47 
48 
49 /**
50  * mei_me_cl_by_id return index to me_clients for client_id
51  *
52  * @dev: the device structure
53  * @client_id: me client id
54  *
55  * Locking: called under "dev->device_lock" lock
56  *
57  * returns index on success, -ENOENT on failure.
58  */
59 
60 int mei_me_cl_by_id(struct mei_device *dev, u8 client_id)
61 {
62 	int i;
63 	for (i = 0; i < dev->me_clients_num; i++)
64 		if (dev->me_clients[i].client_id == client_id)
65 			break;
66 	if (WARN_ON(dev->me_clients[i].client_id != client_id))
67 		return -ENOENT;
68 
69 	if (i == dev->me_clients_num)
70 		return -ENOENT;
71 
72 	return i;
73 }
74 
75 
76 /**
77  * mei_io_list_flush - removes list entry belonging to cl.
78  *
79  * @list:  An instance of our list structure
80  * @cl: host client
81  */
82 void mei_io_list_flush(struct mei_cl_cb *list, struct mei_cl *cl)
83 {
84 	struct mei_cl_cb *cb;
85 	struct mei_cl_cb *next;
86 
87 	list_for_each_entry_safe(cb, next, &list->list, list) {
88 		if (cb->cl && mei_cl_cmp_id(cl, cb->cl))
89 			list_del(&cb->list);
90 	}
91 }
92 
93 /**
94  * mei_io_cb_free - free mei_cb_private related memory
95  *
96  * @cb: mei callback struct
97  */
98 void mei_io_cb_free(struct mei_cl_cb *cb)
99 {
100 	if (cb == NULL)
101 		return;
102 
103 	kfree(cb->request_buffer.data);
104 	kfree(cb->response_buffer.data);
105 	kfree(cb);
106 }
107 
108 /**
109  * mei_io_cb_init - allocate and initialize io callback
110  *
111  * @cl - mei client
112  * @fp: pointer to file structure
113  *
114  * returns mei_cl_cb pointer or NULL;
115  */
116 struct mei_cl_cb *mei_io_cb_init(struct mei_cl *cl, struct file *fp)
117 {
118 	struct mei_cl_cb *cb;
119 
120 	cb = kzalloc(sizeof(struct mei_cl_cb), GFP_KERNEL);
121 	if (!cb)
122 		return NULL;
123 
124 	mei_io_list_init(cb);
125 
126 	cb->file_object = fp;
127 	cb->cl = cl;
128 	cb->buf_idx = 0;
129 	return cb;
130 }
131 
132 /**
133  * mei_io_cb_alloc_req_buf - allocate request buffer
134  *
135  * @cb: io callback structure
136  * @length: size of the buffer
137  *
138  * returns 0 on success
139  *         -EINVAL if cb is NULL
140  *         -ENOMEM if allocation failed
141  */
142 int mei_io_cb_alloc_req_buf(struct mei_cl_cb *cb, size_t length)
143 {
144 	if (!cb)
145 		return -EINVAL;
146 
147 	if (length == 0)
148 		return 0;
149 
150 	cb->request_buffer.data = kmalloc(length, GFP_KERNEL);
151 	if (!cb->request_buffer.data)
152 		return -ENOMEM;
153 	cb->request_buffer.size = length;
154 	return 0;
155 }
156 /**
157  * mei_io_cb_alloc_resp_buf - allocate respose buffer
158  *
159  * @cb: io callback structure
160  * @length: size of the buffer
161  *
162  * returns 0 on success
163  *         -EINVAL if cb is NULL
164  *         -ENOMEM if allocation failed
165  */
166 int mei_io_cb_alloc_resp_buf(struct mei_cl_cb *cb, size_t length)
167 {
168 	if (!cb)
169 		return -EINVAL;
170 
171 	if (length == 0)
172 		return 0;
173 
174 	cb->response_buffer.data = kmalloc(length, GFP_KERNEL);
175 	if (!cb->response_buffer.data)
176 		return -ENOMEM;
177 	cb->response_buffer.size = length;
178 	return 0;
179 }
180 
181 
182 
183 /**
184  * mei_cl_flush_queues - flushes queue lists belonging to cl.
185  *
186  * @cl: host client
187  */
188 int mei_cl_flush_queues(struct mei_cl *cl)
189 {
190 	struct mei_device *dev;
191 
192 	if (WARN_ON(!cl || !cl->dev))
193 		return -EINVAL;
194 
195 	dev = cl->dev;
196 
197 	cl_dbg(dev, cl, "remove list entry belonging to cl\n");
198 	mei_io_list_flush(&cl->dev->read_list, cl);
199 	mei_io_list_flush(&cl->dev->write_list, cl);
200 	mei_io_list_flush(&cl->dev->write_waiting_list, cl);
201 	mei_io_list_flush(&cl->dev->ctrl_wr_list, cl);
202 	mei_io_list_flush(&cl->dev->ctrl_rd_list, cl);
203 	mei_io_list_flush(&cl->dev->amthif_cmd_list, cl);
204 	mei_io_list_flush(&cl->dev->amthif_rd_complete_list, cl);
205 	return 0;
206 }
207 
208 
209 /**
210  * mei_cl_init - initializes intialize cl.
211  *
212  * @cl: host client to be initialized
213  * @dev: mei device
214  */
215 void mei_cl_init(struct mei_cl *cl, struct mei_device *dev)
216 {
217 	memset(cl, 0, sizeof(struct mei_cl));
218 	init_waitqueue_head(&cl->wait);
219 	init_waitqueue_head(&cl->rx_wait);
220 	init_waitqueue_head(&cl->tx_wait);
221 	INIT_LIST_HEAD(&cl->link);
222 	INIT_LIST_HEAD(&cl->device_link);
223 	cl->reading_state = MEI_IDLE;
224 	cl->writing_state = MEI_IDLE;
225 	cl->dev = dev;
226 }
227 
228 /**
229  * mei_cl_allocate - allocates cl  structure and sets it up.
230  *
231  * @dev: mei device
232  * returns  The allocated file or NULL on failure
233  */
234 struct mei_cl *mei_cl_allocate(struct mei_device *dev)
235 {
236 	struct mei_cl *cl;
237 
238 	cl = kmalloc(sizeof(struct mei_cl), GFP_KERNEL);
239 	if (!cl)
240 		return NULL;
241 
242 	mei_cl_init(cl, dev);
243 
244 	return cl;
245 }
246 
247 /**
248  * mei_cl_find_read_cb - find this cl's callback in the read list
249  *
250  * @cl: host client
251  *
252  * returns cb on success, NULL on error
253  */
254 struct mei_cl_cb *mei_cl_find_read_cb(struct mei_cl *cl)
255 {
256 	struct mei_device *dev = cl->dev;
257 	struct mei_cl_cb *cb = NULL;
258 	struct mei_cl_cb *next = NULL;
259 
260 	list_for_each_entry_safe(cb, next, &dev->read_list.list, list)
261 		if (mei_cl_cmp_id(cl, cb->cl))
262 			return cb;
263 	return NULL;
264 }
265 
266 /** mei_cl_link: allocte host id in the host map
267  *
268  * @cl - host client
269  * @id - fixed host id or -1 for genereting one
270  *
271  * returns 0 on success
272  *	-EINVAL on incorrect values
273  *	-ENONET if client not found
274  */
275 int mei_cl_link(struct mei_cl *cl, int id)
276 {
277 	struct mei_device *dev;
278 
279 	if (WARN_ON(!cl || !cl->dev))
280 		return -EINVAL;
281 
282 	dev = cl->dev;
283 
284 	/* If Id is not asigned get one*/
285 	if (id == MEI_HOST_CLIENT_ID_ANY)
286 		id = find_first_zero_bit(dev->host_clients_map,
287 					MEI_CLIENTS_MAX);
288 
289 	if (id >= MEI_CLIENTS_MAX) {
290 		dev_err(&dev->pdev->dev, "id exceded %d", MEI_CLIENTS_MAX) ;
291 		return -ENOENT;
292 	}
293 
294 	if (dev->open_handle_count >= MEI_MAX_OPEN_HANDLE_COUNT) {
295 		dev_err(&dev->pdev->dev, "open_handle_count exceded %d",
296 			MEI_MAX_OPEN_HANDLE_COUNT);
297 		return -ENOENT;
298 	}
299 
300 	dev->open_handle_count++;
301 
302 	cl->host_client_id = id;
303 	list_add_tail(&cl->link, &dev->file_list);
304 
305 	set_bit(id, dev->host_clients_map);
306 
307 	cl->state = MEI_FILE_INITIALIZING;
308 
309 	cl_dbg(dev, cl, "link cl\n");
310 	return 0;
311 }
312 
313 /**
314  * mei_cl_unlink - remove me_cl from the list
315  *
316  * @cl: host client
317  */
318 int mei_cl_unlink(struct mei_cl *cl)
319 {
320 	struct mei_device *dev;
321 
322 	/* don't shout on error exit path */
323 	if (!cl)
324 		return 0;
325 
326 	/* wd and amthif might not be initialized */
327 	if (!cl->dev)
328 		return 0;
329 
330 	dev = cl->dev;
331 
332 	cl_dbg(dev, cl, "unlink client");
333 
334 	list_del_init(&cl->link);
335 
336 	return 0;
337 }
338 
339 
340 void mei_host_client_init(struct work_struct *work)
341 {
342 	struct mei_device *dev = container_of(work,
343 					      struct mei_device, init_work);
344 	struct mei_client_properties *client_props;
345 	int i;
346 
347 	mutex_lock(&dev->device_lock);
348 
349 	bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
350 	dev->open_handle_count = 0;
351 
352 	/*
353 	 * Reserving the first three client IDs
354 	 * 0: Reserved for MEI Bus Message communications
355 	 * 1: Reserved for Watchdog
356 	 * 2: Reserved for AMTHI
357 	 */
358 	bitmap_set(dev->host_clients_map, 0, 3);
359 
360 	for (i = 0; i < dev->me_clients_num; i++) {
361 		client_props = &dev->me_clients[i].props;
362 
363 		if (!uuid_le_cmp(client_props->protocol_name, mei_amthif_guid))
364 			mei_amthif_host_init(dev);
365 		else if (!uuid_le_cmp(client_props->protocol_name, mei_wd_guid))
366 			mei_wd_host_init(dev);
367 		else if (!uuid_le_cmp(client_props->protocol_name, mei_nfc_guid))
368 			mei_nfc_host_init(dev);
369 
370 	}
371 
372 	dev->dev_state = MEI_DEV_ENABLED;
373 
374 	mutex_unlock(&dev->device_lock);
375 }
376 
377 
378 /**
379  * mei_cl_disconnect - disconnect host clinet form the me one
380  *
381  * @cl: host client
382  *
383  * Locking: called under "dev->device_lock" lock
384  *
385  * returns 0 on success, <0 on failure.
386  */
387 int mei_cl_disconnect(struct mei_cl *cl)
388 {
389 	struct mei_device *dev;
390 	struct mei_cl_cb *cb;
391 	int rets, err;
392 
393 	if (WARN_ON(!cl || !cl->dev))
394 		return -ENODEV;
395 
396 	dev = cl->dev;
397 
398 	cl_dbg(dev, cl, "disconnecting");
399 
400 	if (cl->state != MEI_FILE_DISCONNECTING)
401 		return 0;
402 
403 	cb = mei_io_cb_init(cl, NULL);
404 	if (!cb)
405 		return -ENOMEM;
406 
407 	cb->fop_type = MEI_FOP_CLOSE;
408 	if (dev->hbuf_is_ready) {
409 		dev->hbuf_is_ready = false;
410 		if (mei_hbm_cl_disconnect_req(dev, cl)) {
411 			rets = -ENODEV;
412 			cl_err(dev, cl, "failed to disconnect.\n");
413 			goto free;
414 		}
415 		mdelay(10); /* Wait for hardware disconnection ready */
416 		list_add_tail(&cb->list, &dev->ctrl_rd_list.list);
417 	} else {
418 		cl_dbg(dev, cl, "add disconnect cb to control write list\n");
419 		list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
420 
421 	}
422 	mutex_unlock(&dev->device_lock);
423 
424 	err = wait_event_timeout(dev->wait_recvd_msg,
425 			MEI_FILE_DISCONNECTED == cl->state,
426 			mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));
427 
428 	mutex_lock(&dev->device_lock);
429 	if (MEI_FILE_DISCONNECTED == cl->state) {
430 		rets = 0;
431 		cl_dbg(dev, cl, "successfully disconnected from FW client.\n");
432 	} else {
433 		rets = -ENODEV;
434 		if (MEI_FILE_DISCONNECTED != cl->state)
435 			cl_err(dev, cl, "wrong status client disconnect.\n");
436 
437 		if (err)
438 			cl_dbg(dev, cl, "wait failed disconnect err=%08x\n",
439 					err);
440 
441 		cl_err(dev, cl, "failed to disconnect from FW client.\n");
442 	}
443 
444 	mei_io_list_flush(&dev->ctrl_rd_list, cl);
445 	mei_io_list_flush(&dev->ctrl_wr_list, cl);
446 free:
447 	mei_io_cb_free(cb);
448 	return rets;
449 }
450 
451 
452 /**
453  * mei_cl_is_other_connecting - checks if other
454  *    client with the same me client id is connecting
455  *
456  * @cl: private data of the file object
457  *
458  * returns ture if other client is connected, 0 - otherwise.
459  */
460 bool mei_cl_is_other_connecting(struct mei_cl *cl)
461 {
462 	struct mei_device *dev;
463 	struct mei_cl *pos;
464 	struct mei_cl *next;
465 
466 	if (WARN_ON(!cl || !cl->dev))
467 		return false;
468 
469 	dev = cl->dev;
470 
471 	list_for_each_entry_safe(pos, next, &dev->file_list, link) {
472 		if ((pos->state == MEI_FILE_CONNECTING) &&
473 		    (pos != cl) && cl->me_client_id == pos->me_client_id)
474 			return true;
475 
476 	}
477 
478 	return false;
479 }
480 
481 /**
482  * mei_cl_connect - connect host clinet to the me one
483  *
484  * @cl: host client
485  *
486  * Locking: called under "dev->device_lock" lock
487  *
488  * returns 0 on success, <0 on failure.
489  */
490 int mei_cl_connect(struct mei_cl *cl, struct file *file)
491 {
492 	struct mei_device *dev;
493 	struct mei_cl_cb *cb;
494 	int rets;
495 
496 	if (WARN_ON(!cl || !cl->dev))
497 		return -ENODEV;
498 
499 	dev = cl->dev;
500 
501 	cb = mei_io_cb_init(cl, file);
502 	if (!cb) {
503 		rets = -ENOMEM;
504 		goto out;
505 	}
506 
507 	cb->fop_type = MEI_FOP_IOCTL;
508 
509 	if (dev->hbuf_is_ready && !mei_cl_is_other_connecting(cl)) {
510 		dev->hbuf_is_ready = false;
511 
512 		if (mei_hbm_cl_connect_req(dev, cl)) {
513 			rets = -ENODEV;
514 			goto out;
515 		}
516 		cl->timer_count = MEI_CONNECT_TIMEOUT;
517 		list_add_tail(&cb->list, &dev->ctrl_rd_list.list);
518 	} else {
519 		list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
520 	}
521 
522 	mutex_unlock(&dev->device_lock);
523 	rets = wait_event_timeout(dev->wait_recvd_msg,
524 				 (cl->state == MEI_FILE_CONNECTED ||
525 				  cl->state == MEI_FILE_DISCONNECTED),
526 				 mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));
527 	mutex_lock(&dev->device_lock);
528 
529 	if (cl->state != MEI_FILE_CONNECTED) {
530 		rets = -EFAULT;
531 
532 		mei_io_list_flush(&dev->ctrl_rd_list, cl);
533 		mei_io_list_flush(&dev->ctrl_wr_list, cl);
534 		goto out;
535 	}
536 
537 	rets = cl->status;
538 
539 out:
540 	mei_io_cb_free(cb);
541 	return rets;
542 }
543 
544 /**
545  * mei_cl_flow_ctrl_creds - checks flow_control credits for cl.
546  *
547  * @cl: private data of the file object
548  *
549  * returns 1 if mei_flow_ctrl_creds >0, 0 - otherwise.
550  *	-ENOENT if mei_cl is not present
551  *	-EINVAL if single_recv_buf == 0
552  */
553 int mei_cl_flow_ctrl_creds(struct mei_cl *cl)
554 {
555 	struct mei_device *dev;
556 	int i;
557 
558 	if (WARN_ON(!cl || !cl->dev))
559 		return -EINVAL;
560 
561 	dev = cl->dev;
562 
563 	if (!dev->me_clients_num)
564 		return 0;
565 
566 	if (cl->mei_flow_ctrl_creds > 0)
567 		return 1;
568 
569 	for (i = 0; i < dev->me_clients_num; i++) {
570 		struct mei_me_client  *me_cl = &dev->me_clients[i];
571 		if (me_cl->client_id == cl->me_client_id) {
572 			if (me_cl->mei_flow_ctrl_creds) {
573 				if (WARN_ON(me_cl->props.single_recv_buf == 0))
574 					return -EINVAL;
575 				return 1;
576 			} else {
577 				return 0;
578 			}
579 		}
580 	}
581 	return -ENOENT;
582 }
583 
584 /**
585  * mei_cl_flow_ctrl_reduce - reduces flow_control.
586  *
587  * @cl: private data of the file object
588  *
589  * @returns
590  *	0 on success
591  *	-ENOENT when me client is not found
592  *	-EINVAL when ctrl credits are <= 0
593  */
594 int mei_cl_flow_ctrl_reduce(struct mei_cl *cl)
595 {
596 	struct mei_device *dev;
597 	int i;
598 
599 	if (WARN_ON(!cl || !cl->dev))
600 		return -EINVAL;
601 
602 	dev = cl->dev;
603 
604 	if (!dev->me_clients_num)
605 		return -ENOENT;
606 
607 	for (i = 0; i < dev->me_clients_num; i++) {
608 		struct mei_me_client  *me_cl = &dev->me_clients[i];
609 		if (me_cl->client_id == cl->me_client_id) {
610 			if (me_cl->props.single_recv_buf != 0) {
611 				if (WARN_ON(me_cl->mei_flow_ctrl_creds <= 0))
612 					return -EINVAL;
613 				dev->me_clients[i].mei_flow_ctrl_creds--;
614 			} else {
615 				if (WARN_ON(cl->mei_flow_ctrl_creds <= 0))
616 					return -EINVAL;
617 				cl->mei_flow_ctrl_creds--;
618 			}
619 			return 0;
620 		}
621 	}
622 	return -ENOENT;
623 }
624 
625 /**
626  * mei_cl_read_start - the start read client message function.
627  *
628  * @cl: host client
629  *
630  * returns 0 on success, <0 on failure.
631  */
632 int mei_cl_read_start(struct mei_cl *cl, size_t length)
633 {
634 	struct mei_device *dev;
635 	struct mei_cl_cb *cb;
636 	int rets;
637 	int i;
638 
639 	if (WARN_ON(!cl || !cl->dev))
640 		return -ENODEV;
641 
642 	dev = cl->dev;
643 
644 	if (!mei_cl_is_connected(cl))
645 		return -ENODEV;
646 
647 	if (cl->read_cb) {
648 		cl_dbg(dev, cl, "read is pending.\n");
649 		return -EBUSY;
650 	}
651 	i = mei_me_cl_by_id(dev, cl->me_client_id);
652 	if (i < 0) {
653 		cl_err(dev, cl, "no such me client %d\n", cl->me_client_id);
654 		return  -ENODEV;
655 	}
656 
657 	cb = mei_io_cb_init(cl, NULL);
658 	if (!cb)
659 		return -ENOMEM;
660 
661 	/* always allocate at least client max message */
662 	length = max_t(size_t, length, dev->me_clients[i].props.max_msg_length);
663 	rets = mei_io_cb_alloc_resp_buf(cb, length);
664 	if (rets)
665 		goto err;
666 
667 	cb->fop_type = MEI_FOP_READ;
668 	cl->read_cb = cb;
669 	if (dev->hbuf_is_ready) {
670 		dev->hbuf_is_ready = false;
671 		if (mei_hbm_cl_flow_control_req(dev, cl)) {
672 			cl_err(dev, cl, "flow control send failed\n");
673 			rets = -ENODEV;
674 			goto err;
675 		}
676 		list_add_tail(&cb->list, &dev->read_list.list);
677 	} else {
678 		list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
679 	}
680 	return rets;
681 err:
682 	mei_io_cb_free(cb);
683 	return rets;
684 }
685 
686 /**
687  * mei_cl_irq_write_complete - write a message to device
688  *	from the interrupt thread context
689  *
690  * @cl: client
691  * @cb: callback block.
692  * @slots: free slots.
693  * @cmpl_list: complete list.
694  *
695  * returns 0, OK; otherwise error.
696  */
697 int mei_cl_irq_write_complete(struct mei_cl *cl, struct mei_cl_cb *cb,
698 				     s32 *slots, struct mei_cl_cb *cmpl_list)
699 {
700 	struct mei_device *dev;
701 	struct mei_msg_data *buf;
702 	struct mei_msg_hdr mei_hdr;
703 	size_t len;
704 	u32 msg_slots;
705 	int rets;
706 
707 
708 	if (WARN_ON(!cl || !cl->dev))
709 		return -ENODEV;
710 
711 	dev = cl->dev;
712 
713 	buf = &cb->request_buffer;
714 
715 	rets = mei_cl_flow_ctrl_creds(cl);
716 	if (rets < 0)
717 		return rets;
718 
719 	if (rets == 0) {
720 		cl_dbg(dev, cl,	"No flow control credentials: not sending.\n");
721 		return 0;
722 	}
723 
724 	len = buf->size - cb->buf_idx;
725 	msg_slots = mei_data2slots(len);
726 
727 	mei_hdr.host_addr = cl->host_client_id;
728 	mei_hdr.me_addr = cl->me_client_id;
729 	mei_hdr.reserved = 0;
730 
731 	if (*slots >= msg_slots) {
732 		mei_hdr.length = len;
733 		mei_hdr.msg_complete = 1;
734 	/* Split the message only if we can write the whole host buffer */
735 	} else if (*slots == dev->hbuf_depth) {
736 		msg_slots = *slots;
737 		len = (*slots * sizeof(u32)) - sizeof(struct mei_msg_hdr);
738 		mei_hdr.length = len;
739 		mei_hdr.msg_complete = 0;
740 	} else {
741 		/* wait for next time the host buffer is empty */
742 		return 0;
743 	}
744 
745 	cl_dbg(dev, cl, "buf: size = %d idx = %lu\n",
746 			cb->request_buffer.size, cb->buf_idx);
747 
748 	*slots -=  msg_slots;
749 	rets = mei_write_message(dev, &mei_hdr, buf->data + cb->buf_idx);
750 	if (rets) {
751 		cl->status = rets;
752 		list_move_tail(&cb->list, &cmpl_list->list);
753 		return rets;
754 	}
755 
756 	cl->status = 0;
757 	cl->writing_state = MEI_WRITING;
758 	cb->buf_idx += mei_hdr.length;
759 
760 	if (mei_hdr.msg_complete) {
761 		if (mei_cl_flow_ctrl_reduce(cl))
762 			return -EIO;
763 		list_move_tail(&cb->list, &dev->write_waiting_list.list);
764 	}
765 
766 	return 0;
767 }
768 
769 /**
770  * mei_cl_write - submit a write cb to mei device
771 	assumes device_lock is locked
772  *
773  * @cl: host client
774  * @cl: write callback with filled data
775  *
776  * returns numbe of bytes sent on success, <0 on failure.
777  */
778 int mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb, bool blocking)
779 {
780 	struct mei_device *dev;
781 	struct mei_msg_data *buf;
782 	struct mei_msg_hdr mei_hdr;
783 	int rets;
784 
785 
786 	if (WARN_ON(!cl || !cl->dev))
787 		return -ENODEV;
788 
789 	if (WARN_ON(!cb))
790 		return -EINVAL;
791 
792 	dev = cl->dev;
793 
794 
795 	buf = &cb->request_buffer;
796 
797 	cl_dbg(dev, cl, "mei_cl_write %d\n", buf->size);
798 
799 
800 	cb->fop_type = MEI_FOP_WRITE;
801 
802 	rets = mei_cl_flow_ctrl_creds(cl);
803 	if (rets < 0)
804 		goto err;
805 
806 	/* Host buffer is not ready, we queue the request */
807 	if (rets == 0 || !dev->hbuf_is_ready) {
808 		cb->buf_idx = 0;
809 		/* unseting complete will enqueue the cb for write */
810 		mei_hdr.msg_complete = 0;
811 		rets = buf->size;
812 		goto out;
813 	}
814 
815 	dev->hbuf_is_ready = false;
816 
817 	/* Check for a maximum length */
818 	if (buf->size > mei_hbuf_max_len(dev)) {
819 		mei_hdr.length = mei_hbuf_max_len(dev);
820 		mei_hdr.msg_complete = 0;
821 	} else {
822 		mei_hdr.length = buf->size;
823 		mei_hdr.msg_complete = 1;
824 	}
825 
826 	mei_hdr.host_addr = cl->host_client_id;
827 	mei_hdr.me_addr = cl->me_client_id;
828 	mei_hdr.reserved = 0;
829 
830 
831 	rets = mei_write_message(dev, &mei_hdr, buf->data);
832 	if (rets)
833 		goto err;
834 
835 	cl->writing_state = MEI_WRITING;
836 	cb->buf_idx = mei_hdr.length;
837 
838 	rets = buf->size;
839 out:
840 	if (mei_hdr.msg_complete) {
841 		if (mei_cl_flow_ctrl_reduce(cl)) {
842 			rets = -ENODEV;
843 			goto err;
844 		}
845 		list_add_tail(&cb->list, &dev->write_waiting_list.list);
846 	} else {
847 		list_add_tail(&cb->list, &dev->write_list.list);
848 	}
849 
850 
851 	if (blocking && cl->writing_state != MEI_WRITE_COMPLETE) {
852 
853 		mutex_unlock(&dev->device_lock);
854 		if (wait_event_interruptible(cl->tx_wait,
855 			cl->writing_state == MEI_WRITE_COMPLETE)) {
856 				if (signal_pending(current))
857 					rets = -EINTR;
858 				else
859 					rets = -ERESTARTSYS;
860 		}
861 		mutex_lock(&dev->device_lock);
862 	}
863 err:
864 	return rets;
865 }
866 
867 
868 /**
869  * mei_cl_complete - processes completed operation for a client
870  *
871  * @cl: private data of the file object.
872  * @cb: callback block.
873  */
874 void mei_cl_complete(struct mei_cl *cl, struct mei_cl_cb *cb)
875 {
876 	if (cb->fop_type == MEI_FOP_WRITE) {
877 		mei_io_cb_free(cb);
878 		cb = NULL;
879 		cl->writing_state = MEI_WRITE_COMPLETE;
880 		if (waitqueue_active(&cl->tx_wait))
881 			wake_up_interruptible(&cl->tx_wait);
882 
883 	} else if (cb->fop_type == MEI_FOP_READ &&
884 			MEI_READING == cl->reading_state) {
885 		cl->reading_state = MEI_READ_COMPLETE;
886 		if (waitqueue_active(&cl->rx_wait))
887 			wake_up_interruptible(&cl->rx_wait);
888 		else
889 			mei_cl_bus_rx_event(cl);
890 
891 	}
892 }
893 
894 
895 /**
896  * mei_cl_all_disconnect - disconnect forcefully all connected clients
897  *
898  * @dev - mei device
899  */
900 
901 void mei_cl_all_disconnect(struct mei_device *dev)
902 {
903 	struct mei_cl *cl, *next;
904 
905 	list_for_each_entry_safe(cl, next, &dev->file_list, link) {
906 		cl->state = MEI_FILE_DISCONNECTED;
907 		cl->mei_flow_ctrl_creds = 0;
908 		cl->read_cb = NULL;
909 		cl->timer_count = 0;
910 	}
911 }
912 
913 
914 /**
915  * mei_cl_all_wakeup  - wake up all readers and writers they can be interrupted
916  *
917  * @dev  - mei device
918  */
919 void mei_cl_all_wakeup(struct mei_device *dev)
920 {
921 	struct mei_cl *cl, *next;
922 	list_for_each_entry_safe(cl, next, &dev->file_list, link) {
923 		if (waitqueue_active(&cl->rx_wait)) {
924 			cl_dbg(dev, cl, "Waking up reading client!\n");
925 			wake_up_interruptible(&cl->rx_wait);
926 		}
927 		if (waitqueue_active(&cl->tx_wait)) {
928 			cl_dbg(dev, cl, "Waking up writing client!\n");
929 			wake_up_interruptible(&cl->tx_wait);
930 		}
931 	}
932 }
933 
934 /**
935  * mei_cl_all_write_clear - clear all pending writes
936 
937  * @dev - mei device
938  */
939 void mei_cl_all_write_clear(struct mei_device *dev)
940 {
941 	struct mei_cl_cb *cb, *next;
942 
943 	list_for_each_entry_safe(cb, next, &dev->write_list.list, list) {
944 		list_del(&cb->list);
945 		mei_io_cb_free(cb);
946 	}
947 }
948 
949 
950