summaryrefslogtreecommitdiff
path: root/drivers/hid/intel-ish-hid/ishtp/client.c
blob: 405e0d5212cc8d35f1a0c9ba098e408fe9a54a13 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
// SPDX-License-Identifier: GPL-2.0-only
/*
 * ISHTP client logic
 *
 * Copyright (c) 2003-2016, Intel Corporation.
 */

#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <asm/cacheflush.h>
#include "hbm.h"
#include "client.h"

int ishtp_cl_get_tx_free_buffer_size(struct ishtp_cl *cl)
{
	unsigned long tx_free_flags;
	int size;

	spin_lock_irqsave(&cl->tx_free_list_spinlock, tx_free_flags);
	size = cl->tx_ring_free_size * cl->device->fw_client->props.max_msg_length;
	spin_unlock_irqrestore(&cl->tx_free_list_spinlock, tx_free_flags);

	return size;
}
EXPORT_SYMBOL(ishtp_cl_get_tx_free_buffer_size);

int ishtp_cl_get_tx_free_rings(struct ishtp_cl *cl)
{
	return cl->tx_ring_free_size;
}
EXPORT_SYMBOL(ishtp_cl_get_tx_free_rings);

/**
 * ishtp_read_list_flush() - Flush read queue
 * @cl: ishtp client instance
 *
 * Used to remove all entries from read queue for a client
 */
static void ishtp_read_list_flush(struct ishtp_cl *cl)
{
	struct ishtp_cl_rb *rb;
	struct ishtp_cl_rb *next;
	unsigned long	flags;

	spin_lock_irqsave(&cl->dev->read_list_spinlock, flags);
	list_for_each_entry_safe(rb, next, &cl->dev->read_list.list, list)
		if (rb->cl && ishtp_cl_cmp_id(cl, rb->cl)) {
			list_del(&rb->list);
			ishtp_io_rb_free(rb);
		}
	spin_unlock_irqrestore(&cl->dev->read_list_spinlock, flags);
}

/**
 * ishtp_cl_flush_queues() - Flush all queues for a client
 * @cl: ishtp client instance
 *
 * Used to remove all queues for a client. This is called when a client device
 * needs reset due to error, S3 resume or during module removal
 *
 * Return: 0 on success else -EINVAL if device is NULL
 */
int ishtp_cl_flush_queues(struct ishtp_cl *cl)
{
	if (WARN_ON(!cl || !cl->dev))
		return -EINVAL;

	ishtp_read_list_flush(cl);

	return 0;
}
EXPORT_SYMBOL(ishtp_cl_flush_queues);

/**
 * ishtp_cl_init() - Initialize all fields of a client device
 * @cl: ishtp client instance
 * @dev: ishtp device
 *
 * Initializes a client device fields: Init spinlocks, init queues etc.
 * This function is called during new client creation
 */
static void ishtp_cl_init(struct ishtp_cl *cl, struct ishtp_device *dev)
{
	memset(cl, 0, sizeof(struct ishtp_cl));
	init_waitqueue_head(&cl->wait_ctrl_res);
	spin_lock_init(&cl->free_list_spinlock);
	spin_lock_init(&cl->in_process_spinlock);
	spin_lock_init(&cl->tx_list_spinlock);
	spin_lock_init(&cl->tx_free_list_spinlock);
	spin_lock_init(&cl->fc_spinlock);
	INIT_LIST_HEAD(&cl->link);
	cl->dev = dev;

	INIT_LIST_HEAD(&cl->free_rb_list.list);
	INIT_LIST_HEAD(&cl->tx_list.list);
	INIT_LIST_HEAD(&cl->tx_free_list.list);
	INIT_LIST_HEAD(&cl->in_process_list.list);

	cl->rx_ring_size = CL_DEF_RX_RING_SIZE;
	cl->tx_ring_size = CL_DEF_TX_RING_SIZE;
	cl->tx_ring_free_size = cl->tx_ring_size;

	/* dma */
	cl->last_tx_path = CL_TX_PATH_IPC;
	cl->last_dma_acked = 1;
	cl->last_dma_addr = NULL;
	cl->last_ipc_acked = 1;
}

/**
 * ishtp_cl_allocate() - allocates client structure and sets it up.
 * @cl_device: ishtp client device
 *
 * Allocate memory for new client device and call to initialize each field.
 *
 * Return: The allocated client instance or NULL on failure
 */
struct ishtp_cl *ishtp_cl_allocate(struct ishtp_cl_device *cl_device)
{
	struct ishtp_cl *cl;

	cl = kmalloc(sizeof(struct ishtp_cl), GFP_KERNEL);
	if (!cl)
		return NULL;

	ishtp_cl_init(cl, cl_device->ishtp_dev);
	return cl;
}
EXPORT_SYMBOL(ishtp_cl_allocate);

/**
 * ishtp_cl_free() - Frees a client device
 * @cl: client device instance
 *
 * Frees a client device
 */
void	ishtp_cl_free(struct ishtp_cl *cl)
{
	struct ishtp_device *dev;
	unsigned long flags;

	if (!cl)
		return;

	dev = cl->dev;
	if (!dev)
		return;

	spin_lock_irqsave(&dev->cl_list_lock, flags);
	ishtp_cl_free_rx_ring(cl);
	ishtp_cl_free_tx_ring(cl);
	kfree(cl);
	spin_unlock_irqrestore(&dev->cl_list_lock, flags);
}
EXPORT_SYMBOL(ishtp_cl_free);

/**
 * ishtp_cl_link() - Reserve a host id and link the client instance
 * @cl: client device instance
 *
 * This allocates a single bit in the hostmap. This function will make sure
 * that not many client sessions are opened at the same time. Once allocated
 * the client device instance is added to the ishtp device in the current
 * client list
 *
 * Return: 0 or error code on failure
 */
int ishtp_cl_link(struct ishtp_cl *cl)
{
	struct ishtp_device *dev;
	unsigned long flags, flags_cl;
	int id, ret = 0;

	if (WARN_ON(!cl || !cl->dev))
		return -EINVAL;

	dev = cl->dev;

	spin_lock_irqsave(&dev->device_lock, flags);

	if (dev->open_handle_count >= ISHTP_MAX_OPEN_HANDLE_COUNT) {
		ret = -EMFILE;
		goto unlock_dev;
	}

	id = find_first_zero_bit(dev->host_clients_map, ISHTP_CLIENTS_MAX);

	if (id >= ISHTP_CLIENTS_MAX) {
		spin_unlock_irqrestore(&dev->device_lock, flags);
		dev_err(&cl->device->dev, "id exceeded %d", ISHTP_CLIENTS_MAX);
		return -ENOENT;
	}

	dev->open_handle_count++;
	cl->host_client_id = id;
	spin_lock_irqsave(&dev->cl_list_lock, flags_cl);
	if (dev->dev_state != ISHTP_DEV_ENABLED) {
		ret = -ENODEV;
		goto unlock_cl;
	}
	list_add_tail(&cl->link, &dev->cl_list);
	set_bit(id, dev->host_clients_map);
	cl->state = ISHTP_CL_INITIALIZING;

unlock_cl:
	spin_unlock_irqrestore(&dev->cl_list_lock, flags_cl);
unlock_dev:
	spin_unlock_irqrestore(&dev->device_lock, flags);
	return ret;
}
EXPORT_SYMBOL(ishtp_cl_link);

/**
 * ishtp_cl_unlink() - remove fw_cl from the client device list
 * @cl: client device instance
 *
 * Remove a previously linked device to a ishtp device
 */
void ishtp_cl_unlink(struct ishtp_cl *cl)
{
	struct ishtp_device *dev;
	struct ishtp_cl *pos;
	unsigned long	flags;

	/* don't shout on error exit path */
	if (!cl || !cl->dev)
		return;

	dev = cl->dev;

	spin_lock_irqsave(&dev->device_lock, flags);
	if (dev->open_handle_count > 0) {
		clear_bit(cl->host_client_id, dev->host_clients_map);
		dev->open_handle_count--;
	}
	spin_unlock_irqrestore(&dev->device_lock, flags);

	/*
	 * This checks that 'cl' is actually linked into device's structure,
	 * before attempting 'list_del'
	 */
	spin_lock_irqsave(&dev->cl_list_lock, flags);
	list_for_each_entry(pos, &dev->cl_list, link)
		if (cl->host_client_id == pos->host_client_id) {
			list_del_init(&pos->link);
			break;
		}
	spin_unlock_irqrestore(&dev->cl_list_lock, flags);
}
EXPORT_SYMBOL(ishtp_cl_unlink);

/**
 * ishtp_cl_disconnect() - Send disconnect request to firmware
 * @cl: client device instance
 *
 * Send a disconnect request for a client to firmware.
 *
 * Return: 0 if successful disconnect response from the firmware or error
 * code on failure
 */
int ishtp_cl_disconnect(struct ishtp_cl *cl)
{
	struct ishtp_device *dev;

	if (WARN_ON(!cl || !cl->dev))
		return -ENODEV;

	dev = cl->dev;

	dev->print_log(dev, "%s() state %d\n", __func__, cl->state);

	if (cl->state != ISHTP_CL_DISCONNECTING) {
		dev->print_log(dev, "%s() Disconnect in progress\n", __func__);
		return 0;
	}

	if (ishtp_hbm_cl_disconnect_req(dev, cl)) {
		dev->print_log(dev, "%s() Failed to disconnect\n", __func__);
		dev_err(&cl->device->dev, "failed to disconnect.\n");
		return -ENODEV;
	}

	wait_event_interruptible_timeout(cl->wait_ctrl_res,
			(dev->dev_state != ISHTP_DEV_ENABLED ||
			cl->state == ISHTP_CL_DISCONNECTED),
			ishtp_secs_to_jiffies(ISHTP_CL_CONNECT_TIMEOUT));

	/*
	 * If FW reset arrived, this will happen. Don't check cl->,
	 * as 'cl' may be freed already
	 */
	if (dev->dev_state != ISHTP_DEV_ENABLED) {
		dev->print_log(dev, "%s() dev_state != ISHTP_DEV_ENABLED\n",
			       __func__);
		return -ENODEV;
	}

	if (cl->state == ISHTP_CL_DISCONNECTED) {
		dev->print_log(dev, "%s() successful\n", __func__);
		return 0;
	}

	return -ENODEV;
}
EXPORT_SYMBOL(ishtp_cl_disconnect);

/**
 * ishtp_cl_is_other_connecting() - Check other client is connecting
 * @cl: client device instance
 *
 * Checks if other client with the same fw client id is connecting
 *
 * Return: true if other client is connected else false
 */
static bool ishtp_cl_is_other_connecting(struct ishtp_cl *cl)
{
	struct ishtp_device *dev;
	struct ishtp_cl *pos;
	unsigned long	flags;

	if (WARN_ON(!cl || !cl->dev))
		return false;

	dev = cl->dev;
	spin_lock_irqsave(&dev->cl_list_lock, flags);
	list_for_each_entry(pos, &dev->cl_list, link) {
		if ((pos->state == ISHTP_CL_CONNECTING) && (pos != cl) &&
				cl->fw_client_id == pos->fw_client_id) {
			spin_unlock_irqrestore(&dev->cl_list_lock, flags);
			return true;
		}
	}
	spin_unlock_irqrestore(&dev->cl_list_lock, flags);

	return false;
}

/**
 * ishtp_cl_connect() - Send connect request to firmware
 * @cl: client device instance
 *
 * Send a connect request for a client to firmware. If successful it will
 * RX and TX ring buffers
 *
 * Return: 0 if successful connect response from the firmware and able
 * to bind and allocate ring buffers or error code on failure
 */
int ishtp_cl_connect(struct ishtp_cl *cl)
{
	struct ishtp_device *dev;
	int rets;

	if (WARN_ON(!cl || !cl->dev))
		return -ENODEV;

	dev = cl->dev;

	dev->print_log(dev, "%s() current_state = %d\n", __func__, cl->state);

	if (ishtp_cl_is_other_connecting(cl)) {
		dev->print_log(dev, "%s() Busy\n", __func__);
		return	-EBUSY;
	}

	if (ishtp_hbm_cl_connect_req(dev, cl)) {
		dev->print_log(dev, "%s() HBM connect req fail\n", __func__);
		return -ENODEV;
	}

	rets = wait_event_interruptible_timeout(cl->wait_ctrl_res,
				(dev->dev_state == ISHTP_DEV_ENABLED &&
				(cl->state == ISHTP_CL_CONNECTED ||
				 cl->state == ISHTP_CL_DISCONNECTED)),
				ishtp_secs_to_jiffies(
					ISHTP_CL_CONNECT_TIMEOUT));
	/*
	 * If FW reset arrived, this will happen. Don't check cl->,
	 * as 'cl' may be freed already
	 */
	if (dev->dev_state != ISHTP_DEV_ENABLED) {
		dev->print_log(dev, "%s() dev_state != ISHTP_DEV_ENABLED\n",
			       __func__);
		return -EFAULT;
	}

	if (cl->state != ISHTP_CL_CONNECTED) {
		dev->print_log(dev, "%s() state != ISHTP_CL_CONNECTED\n",
			       __func__);
		return -EFAULT;
	}

	rets = cl->status;
	if (rets) {
		dev->print_log(dev, "%s() Invalid status\n", __func__);
		return rets;
	}

	rets = ishtp_cl_device_bind(cl);
	if (rets) {
		dev->print_log(dev, "%s() Bind error\n", __func__);
		ishtp_cl_disconnect(cl);
		return rets;
	}

	rets = ishtp_cl_alloc_rx_ring(cl);
	if (rets) {
		dev->print_log(dev, "%s() Alloc RX ring failed\n", __func__);
		/* if failed allocation, disconnect */
		ishtp_cl_disconnect(cl);
		return rets;
	}

	rets = ishtp_cl_alloc_tx_ring(cl);
	if (rets) {
		dev->print_log(dev, "%s() Alloc TX ring failed\n", __func__);
		/* if failed allocation, disconnect */
		ishtp_cl_free_rx_ring(cl);
		ishtp_cl_disconnect(cl);
		return rets;
	}

	/* Upon successful connection and allocation, emit flow-control */
	rets = ishtp_cl_read_start(cl);

	dev->print_log(dev, "%s() successful\n", __func__);

	return rets;
}
EXPORT_SYMBOL(ishtp_cl_connect);

/**
 * ishtp_cl_read_start() - Prepare to read client message
 * @cl: client device instance
 *
 * Get a free buffer from pool of free read buffers and add to read buffer
 * pool to add contents. Send a flow control request to firmware to be able
 * send next message.
 *
 * Return: 0 if successful or error code on failure
 */
int ishtp_cl_read_start(struct ishtp_cl *cl)
{
	struct ishtp_device *dev;
	struct ishtp_cl_rb *rb;
	int rets;
	int i;
	unsigned long	flags;
	unsigned long	dev_flags;

	if (WARN_ON(!cl || !cl->dev))
		return -ENODEV;

	dev = cl->dev;

	if (cl->state != ISHTP_CL_CONNECTED)
		return -ENODEV;

	if (dev->dev_state != ISHTP_DEV_ENABLED)
		return -ENODEV;

	i = ishtp_fw_cl_by_id(dev, cl->fw_client_id);
	if (i < 0) {
		dev_err(&cl->device->dev, "no such fw client %d\n",
			cl->fw_client_id);
		return -ENODEV;
	}

	/* The current rb is the head of the free rb list */
	spin_lock_irqsave(&cl->free_list_spinlock, flags);
	if (list_empty(&cl->free_rb_list.list)) {
		dev_warn(&cl->device->dev,
			 "[ishtp-ish] Rx buffers pool is empty\n");
		rets = -ENOMEM;
		rb = NULL;
		spin_unlock_irqrestore(&cl->free_list_spinlock, flags);
		goto out;
	}
	rb = list_entry(cl->free_rb_list.list.next, struct ishtp_cl_rb, list);
	list_del_init(&rb->list);
	spin_unlock_irqrestore(&cl->free_list_spinlock, flags);

	rb->cl = cl;
	rb->buf_idx = 0;

	INIT_LIST_HEAD(&rb->list);
	rets = 0;

	/*
	 * This must be BEFORE sending flow control -
	 * response in ISR may come too fast...
	 */
	spin_lock_irqsave(&dev->read_list_spinlock, dev_flags);
	list_add_tail(&rb->list, &dev->read_list.list);
	spin_unlock_irqrestore(&dev->read_list_spinlock, dev_flags);
	if (ishtp_hbm_cl_flow_control_req(dev, cl)) {
		rets = -ENODEV;
		goto out;
	}
out:
	/* if ishtp_hbm_cl_flow_control_req failed, return rb to free list */
	if (rets && rb) {
		spin_lock_irqsave(&dev->read_list_spinlock, dev_flags);
		list_del(&rb->list);
		spin_unlock_irqrestore(&dev->read_list_spinlock, dev_flags);

		spin_lock_irqsave(&cl->free_list_spinlock, flags);
		list_add_tail(&rb->list, &cl->free_rb_list.list);
		spin_unlock_irqrestore(&cl->free_list_spinlock, flags);
	}
	return rets;
}

/**
 * ishtp_cl_send() - Send a message to firmware
 * @cl: client device instance
 * @buf: message buffer
 * @length: length of message
 *
 * If the client is correct state to send message, this function gets a buffer
 * from tx ring buffers, copy the message data and call to send the message
 * using ishtp_cl_send_msg()
 *
 * Return: 0 if successful or error code on failure
 */
int ishtp_cl_send(struct ishtp_cl *cl, uint8_t *buf, size_t length)
{
	struct ishtp_device	*dev;
	int	id;
	struct ishtp_cl_tx_ring	*cl_msg;
	int	have_msg_to_send = 0;
	unsigned long	tx_flags, tx_free_flags;

	if (WARN_ON(!cl || !cl->dev))
		return -ENODEV;

	dev = cl->dev;

	if (cl->state != ISHTP_CL_CONNECTED) {
		++cl->err_send_msg;
		return -EPIPE;
	}

	if (dev->dev_state != ISHTP_DEV_ENABLED) {
		++cl->err_send_msg;
		return -ENODEV;
	}

	/* Check if we have fw client device */
	id = ishtp_fw_cl_by_id(dev, cl->fw_client_id);
	if (id < 0) {
		++cl->err_send_msg;
		return -ENOENT;
	}

	if (length > dev->fw_clients[id].props.max_msg_length) {
		++cl->err_send_msg;
		return -EMSGSIZE;
	}

	/* No free bufs */
	spin_lock_irqsave(&cl->tx_free_list_spinlock, tx_free_flags);
	if (list_empty(&cl->tx_free_list.list)) {
		spin_unlock_irqrestore(&cl->tx_free_list_spinlock,
			tx_free_flags);
		++cl->err_send_msg;
		return	-ENOMEM;
	}

	cl_msg = list_first_entry(&cl->tx_free_list.list,
		struct ishtp_cl_tx_ring, list);
	if (!cl_msg->send_buf.data) {
		spin_unlock_irqrestore(&cl->tx_free_list_spinlock,
			tx_free_flags);
		return	-EIO;
		/* Should not happen, as free list is pre-allocated */
	}
	/*
	 * This is safe, as 'length' is already checked for not exceeding
	 * max ISHTP message size per client
	 */
	list_del_init(&cl_msg->list);
	--cl->tx_ring_free_size;

	spin_unlock_irqrestore(&cl->tx_free_list_spinlock, tx_free_flags);
	memcpy(cl_msg->send_buf.data, buf, length);
	cl_msg->send_buf.size = length;
	spin_lock_irqsave(&cl->tx_list_spinlock, tx_flags);
	have_msg_to_send = !list_empty(&cl->tx_list.list);
	list_add_tail(&cl_msg->list, &cl->tx_list.list);
	spin_unlock_irqrestore(&cl->tx_list_spinlock, tx_flags);

	if (!have_msg_to_send && cl->ishtp_flow_ctrl_creds > 0)
		ishtp_cl_send_msg(dev, cl);

	return	0;
}
EXPORT_SYMBOL(ishtp_cl_send);

/**
 * ishtp_cl_read_complete() - read complete
 * @rb: Pointer to client request block
 *
 * If the message is completely received call ishtp_cl_bus_rx_event()
 * to process message
 */
static void ishtp_cl_read_complete(struct ishtp_cl_rb *rb)
{
	unsigned long	flags;
	int	schedule_work_flag = 0;
	struct ishtp_cl	*cl = rb->cl;

	spin_lock_irqsave(&cl->in_process_spinlock, flags);
	/*
	 * if in-process list is empty, then need to schedule
	 * the processing thread
	 */
	schedule_work_flag = list_empty(&cl->in_process_list.list);
	list_add_tail(&rb->list, &cl->in_process_list.list);
	spin_unlock_irqrestore(&cl->in_process_spinlock, flags);

	if (schedule_work_flag)
		ishtp_cl_bus_rx_event(cl->device);
}

/**
 * ipc_tx_callback() - IPC tx callback function
 * @prm: Pointer to client device instance
 *
 * Send message over IPC either first time or on callback on previous message
 * completion
 */
static void ipc_tx_callback(void *prm)
{
	struct ishtp_cl	*cl = prm;
	struct ishtp_cl_tx_ring	*cl_msg;
	size_t	rem;
	struct ishtp_device	*dev = (cl ? cl->dev : NULL);
	struct ishtp_msg_hdr	ishtp_hdr;
	unsigned long	tx_flags, tx_free_flags;
	unsigned char	*pmsg;

	if (!dev)
		return;

	/*
	 * Other conditions if some critical error has
	 * occurred before this callback is called
	 */
	if (dev->dev_state != ISHTP_DEV_ENABLED)
		return;

	if (cl->state != ISHTP_CL_CONNECTED)
		return;

	spin_lock_irqsave(&cl->tx_list_spinlock, tx_flags);
	if (list_empty(&cl->tx_list.list)) {
		spin_unlock_irqrestore(&cl->tx_list_spinlock, tx_flags);
		return;
	}

	if (cl->ishtp_flow_ctrl_creds != 1 && !cl->sending) {
		spin_unlock_irqrestore(&cl->tx_list_spinlock, tx_flags);
		return;
	}

	if (!cl->sending) {
		--cl->ishtp_flow_ctrl_creds;
		cl->last_ipc_acked = 0;
		cl->last_tx_path = CL_TX_PATH_IPC;
		cl->sending = 1;
	}

	cl_msg = list_entry(cl->tx_list.list.next, struct ishtp_cl_tx_ring,
			    list);
	rem = cl_msg->send_buf.size - cl->tx_offs;

	ishtp_hdr.host_addr = cl->host_client_id;
	ishtp_hdr.fw_addr = cl->fw_client_id;
	ishtp_hdr.reserved = 0;
	pmsg = cl_msg->send_buf.data + cl->tx_offs;

	if (rem <= dev->mtu) {
		ishtp_hdr.length = rem;
		ishtp_hdr.msg_complete = 1;
		cl->sending = 0;
		list_del_init(&cl_msg->list);	/* Must be before write */
		spin_unlock_irqrestore(&cl->tx_list_spinlock, tx_flags);
		/* Submit to IPC queue with no callback */
		ishtp_write_message(dev, &ishtp_hdr, pmsg);
		spin_lock_irqsave(&cl->tx_free_list_spinlock, tx_free_flags);
		list_add_tail(&cl_msg->list, &cl->tx_free_list.list);
		++cl->tx_ring_free_size;
		spin_unlock_irqrestore(&cl->tx_free_list_spinlock,
			tx_free_flags);
	} else {
		/* Send IPC fragment */
		spin_unlock_irqrestore(&cl->tx_list_spinlock, tx_flags);
		cl->tx_offs += dev->mtu;
		ishtp_hdr.length = dev->mtu;
		ishtp_hdr.msg_complete = 0;
		ishtp_send_msg(dev, &ishtp_hdr, pmsg, ipc_tx_callback, cl);
	}
}

/**
 * ishtp_cl_send_msg_ipc() -Send message using IPC
 * @dev: ISHTP device instance
 * @cl: Pointer to client device instance
 *
 * Send message over IPC not using DMA
 */
static void ishtp_cl_send_msg_ipc(struct ishtp_device *dev,
				  struct ishtp_cl *cl)
{
	/* If last DMA message wasn't acked yet, leave this one in Tx queue */
	if (cl->last_tx_path == CL_TX_PATH_DMA && cl->last_dma_acked == 0)
		return;

	cl->tx_offs = 0;
	ipc_tx_callback(cl);
	++cl->send_msg_cnt_ipc;
}

/**
 * ishtp_cl_send_msg_dma() -Send message using DMA
 * @dev: ISHTP device instance
 * @cl: Pointer to client device instance
 *
 * Send message using DMA
 */
static void ishtp_cl_send_msg_dma(struct ishtp_device *dev,
	struct ishtp_cl *cl)
{
	struct ishtp_msg_hdr	hdr;
	struct dma_xfer_hbm	dma_xfer;
	unsigned char	*msg_addr;
	int off;
	struct ishtp_cl_tx_ring	*cl_msg;
	unsigned long tx_flags, tx_free_flags;

	/* If last IPC message wasn't acked yet, leave this one in Tx queue */
	if (cl->last_tx_path == CL_TX_PATH_IPC && cl->last_ipc_acked == 0)
		return;

	spin_lock_irqsave(&cl->tx_list_spinlock, tx_flags);
	if (list_empty(&cl->tx_list.list)) {
		spin_unlock_irqrestore(&cl->tx_list_spinlock, tx_flags);
		return;
	}

	cl_msg = list_entry(cl->tx_list.list.next, struct ishtp_cl_tx_ring,
		list);

	msg_addr = ishtp_cl_get_dma_send_buf(dev, cl_msg->send_buf.size);
	if (!msg_addr) {
		spin_unlock_irqrestore(&cl->tx_list_spinlock, tx_flags);
		if (dev->transfer_path == CL_TX_PATH_DEFAULT)
			ishtp_cl_send_msg_ipc(dev, cl);
		return;
	}

	list_del_init(&cl_msg->list);	/* Must be before write */
	spin_unlock_irqrestore(&cl->tx_list_spinlock, tx_flags);

	--cl->ishtp_flow_ctrl_creds;
	cl->last_dma_acked = 0;
	cl->last_dma_addr = msg_addr;
	cl->last_tx_path = CL_TX_PATH_DMA;

	/* write msg to dma buf */
	memcpy(msg_addr, cl_msg->send_buf.data, cl_msg->send_buf.size);

	/*
	 * if current fw don't support cache snooping, driver have to
	 * flush the cache manually.
	 */
	if (dev->ops->dma_no_cache_snooping &&
		dev->ops->dma_no_cache_snooping(dev))
		clflush_cache_range(msg_addr, cl_msg->send_buf.size);

	/* send dma_xfer hbm msg */
	off = msg_addr - (unsigned char *)dev->ishtp_host_dma_tx_buf;
	ishtp_hbm_hdr(&hdr, sizeof(struct dma_xfer_hbm));
	dma_xfer.hbm = DMA_XFER;
	dma_xfer.fw_client_id = cl->fw_client_id;
	dma_xfer.host_client_id = cl->host_client_id;
	dma_xfer.reserved = 0;
	dma_xfer.msg_addr = dev->ishtp_host_dma_tx_buf_phys + off;
	dma_xfer.msg_length = cl_msg->send_buf.size;
	dma_xfer.reserved2 = 0;
	ishtp_write_message(dev, &hdr, (unsigned char *)&dma_xfer);
	spin_lock_irqsave(&cl->tx_free_list_spinlock, tx_free_flags);
	list_add_tail(&cl_msg->list, &cl->tx_free_list.list);
	++cl->tx_ring_free_size;
	spin_unlock_irqrestore(&cl->tx_free_list_spinlock, tx_free_flags);
	++cl->send_msg_cnt_dma;
}

/**
 * ishtp_cl_send_msg() -Send message using DMA or IPC
 * @dev: ISHTP device instance
 * @cl: Pointer to client device instance
 *
 * Send message using DMA or IPC based on transfer_path
 */
void ishtp_cl_send_msg(struct ishtp_device *dev, struct ishtp_cl *cl)
{
	if (dev->transfer_path == CL_TX_PATH_DMA)
		ishtp_cl_send_msg_dma(dev, cl);
	else
		ishtp_cl_send_msg_ipc(dev, cl);
}

/**
 * recv_ishtp_cl_msg() -Receive client message
 * @dev: ISHTP device instance
 * @ishtp_hdr: Pointer to message header
 *
 * Receive and dispatch ISHTP client messages. This function executes in ISR
 * or work queue context
 */
void recv_ishtp_cl_msg(struct ishtp_device *dev,
		       struct ishtp_msg_hdr *ishtp_hdr)
{
	struct ishtp_cl *cl;
	struct ishtp_cl_rb *rb;
	struct ishtp_cl_rb *new_rb;
	unsigned char *buffer = NULL;
	struct ishtp_cl_rb *complete_rb = NULL;
	unsigned long	flags;
	int	rb_count;

	if (ishtp_hdr->reserved) {
		dev_err(dev->devc, "corrupted message header.\n");
		goto	eoi;
	}

	if (ishtp_hdr->length > IPC_PAYLOAD_SIZE) {
		dev_err(dev->devc,
			"ISHTP message length in hdr exceeds IPC MTU\n");
		goto	eoi;
	}

	spin_lock_irqsave(&dev->read_list_spinlock, flags);
	rb_count = -1;
	list_for_each_entry(rb, &dev->read_list.list, list) {
		++rb_count;
		cl = rb->cl;
		if (!cl || !(cl->host_client_id == ishtp_hdr->host_addr &&
				cl->fw_client_id == ishtp_hdr->fw_addr) ||
				!(cl->state == ISHTP_CL_CONNECTED))
			continue;

		 /* If no Rx buffer is allocated, disband the rb */
		if (rb->buffer.size == 0 || rb->buffer.data == NULL) {
			spin_unlock_irqrestore(&dev->read_list_spinlock, flags);
			dev_err(&cl->device->dev,
				"Rx buffer is not allocated.\n");
			list_del(&rb->list);
			ishtp_io_rb_free(rb);
			cl->status = -ENOMEM;
			goto	eoi;
		}

		/*
		 * If message buffer overflown (exceeds max. client msg
		 * size, drop message and return to free buffer.
		 * Do we need to disconnect such a client? (We don't send
		 * back FC, so communication will be stuck anyway)
		 */
		if (rb->buffer.size < ishtp_hdr->length + rb->buf_idx) {
			spin_unlock_irqrestore(&dev->read_list_spinlock, flags);
			dev_err(&cl->device->dev,
				"message overflow. size %d len %d idx %ld\n",
				rb->buffer.size, ishtp_hdr->length,
				rb->buf_idx);
			list_del(&rb->list);
			ishtp_cl_io_rb_recycle(rb);
			cl->status = -EIO;
			goto	eoi;
		}

		buffer = rb->buffer.data + rb->buf_idx;
		dev->ops->ishtp_read(dev, buffer, ishtp_hdr->length);

		rb->buf_idx += ishtp_hdr->length;
		if (ishtp_hdr->msg_complete) {
			/* Last fragment in message - it's complete */
			cl->status = 0;
			list_del(&rb->list);
			complete_rb = rb;

			--cl->out_flow_ctrl_creds;
			/*
			 * the whole msg arrived, send a new FC, and add a new
			 * rb buffer for the next coming msg
			 */
			spin_lock(&cl->free_list_spinlock);

			if (!list_empty(&cl->free_rb_list.list)) {
				new_rb = list_entry(cl->free_rb_list.list.next,
					struct ishtp_cl_rb, list);
				list_del_init(&new_rb->list);
				spin_unlock(&cl->free_list_spinlock);
				new_rb->cl = cl;
				new_rb->buf_idx = 0;
				INIT_LIST_HEAD(&new_rb->list);
				list_add_tail(&new_rb->list,
					&dev->read_list.list);

				ishtp_hbm_cl_flow_control_req(dev, cl);
			} else {
				spin_unlock(&cl->free_list_spinlock);
			}
		}
		/* One more fragment in message (even if this was last) */
		++cl->recv_msg_num_frags;

		/*
		 * We can safely break here (and in BH too),
		 * a single input message can go only to a single request!
		 */
		break;
	}

	spin_unlock_irqrestore(&dev->read_list_spinlock, flags);
	/* If it's nobody's message, just read and discard it */
	if (!buffer) {
		uint8_t	rd_msg_buf[ISHTP_RD_MSG_BUF_SIZE];

		dev_err(dev->devc, "Dropped Rx msg - no request\n");
		dev->ops->ishtp_read(dev, rd_msg_buf, ishtp_hdr->length);
		goto	eoi;
	}

	if (complete_rb) {
		cl = complete_rb->cl;
		cl->ts_rx = ktime_get();
		++cl->recv_msg_cnt_ipc;
		ishtp_cl_read_complete(complete_rb);
	}
eoi:
	return;
}

/**
 * recv_ishtp_cl_msg_dma() -Receive client message
 * @dev: ISHTP device instance
 * @msg: message pointer
 * @hbm: hbm buffer
 *
 * Receive and dispatch ISHTP client messages using DMA. This function executes
 * in ISR or work queue context
 */
void recv_ishtp_cl_msg_dma(struct ishtp_device *dev, void *msg,
			   struct dma_xfer_hbm *hbm)
{
	struct ishtp_cl *cl;
	struct ishtp_cl_rb *rb;
	struct ishtp_cl_rb *new_rb;
	unsigned char *buffer = NULL;
	struct ishtp_cl_rb *complete_rb = NULL;
	unsigned long	flags;

	spin_lock_irqsave(&dev->read_list_spinlock, flags);

	list_for_each_entry(rb, &dev->read_list.list, list) {
		cl = rb->cl;
		if (!cl || !(cl->host_client_id == hbm->host_client_id &&
				cl->fw_client_id == hbm->fw_client_id) ||
				!(cl->state == ISHTP_CL_CONNECTED))
			continue;

		/*
		 * If no Rx buffer is allocated, disband the rb
		 */
		if (rb->buffer.size == 0 || rb->buffer.data == NULL) {
			spin_unlock_irqrestore(&dev->read_list_spinlock, flags);
			dev_err(&cl->device->dev,
				"response buffer is not allocated.\n");
			list_del(&rb->list);
			ishtp_io_rb_free(rb);
			cl->status = -ENOMEM;
			goto	eoi;
		}

		/*
		 * If message buffer overflown (exceeds max. client msg
		 * size, drop message and return to free buffer.
		 * Do we need to disconnect such a client? (We don't send
		 * back FC, so communication will be stuck anyway)
		 */
		if (rb->buffer.size < hbm->msg_length) {
			spin_unlock_irqrestore(&dev->read_list_spinlock, flags);
			dev_err(&cl->device->dev,
				"message overflow. size %d len %d idx %ld\n",
				rb->buffer.size, hbm->msg_length, rb->buf_idx);
			list_del(&rb->list);
			ishtp_cl_io_rb_recycle(rb);
			cl->status = -EIO;
			goto	eoi;
		}

		buffer = rb->buffer.data;

		/*
		 * if current fw don't support cache snooping, driver have to
		 * flush the cache manually.
		 */
		if (dev->ops->dma_no_cache_snooping &&
			dev->ops->dma_no_cache_snooping(dev))
			clflush_cache_range(msg, hbm->msg_length);

		memcpy(buffer, msg, hbm->msg_length);
		rb->buf_idx = hbm->msg_length;

		/* Last fragment in message - it's complete */
		cl->status = 0;
		list_del(&rb->list);
		complete_rb = rb;

		--cl->out_flow_ctrl_creds;
		/*
		 * the whole msg arrived, send a new FC, and add a new
		 * rb buffer for the next coming msg
		 */
		spin_lock(&cl->free_list_spinlock);

		if (!list_empty(&cl->free_rb_list.list)) {
			new_rb = list_entry(cl->free_rb_list.list.next,
				struct ishtp_cl_rb, list);
			list_del_init(&new_rb->list);
			spin_unlock(&cl->free_list_spinlock);
			new_rb->cl = cl;
			new_rb->buf_idx = 0;
			INIT_LIST_HEAD(&new_rb->list);
			list_add_tail(&new_rb->list,
				&dev->read_list.list);

			ishtp_hbm_cl_flow_control_req(dev, cl);
		} else {
			spin_unlock(&cl->free_list_spinlock);
		}

		/* One more fragment in message (this is always last) */
		++cl->recv_msg_num_frags;

		/*
		 * We can safely break here (and in BH too),
		 * a single input message can go only to a single request!
		 */
		break;
	}

	spin_unlock_irqrestore(&dev->read_list_spinlock, flags);
	/* If it's nobody's message, just read and discard it */
	if (!buffer) {
		dev_err(dev->devc, "Dropped Rx (DMA) msg - no request\n");
		goto	eoi;
	}

	if (complete_rb) {
		cl = complete_rb->cl;
		cl->ts_rx = ktime_get();
		++cl->recv_msg_cnt_dma;
		ishtp_cl_read_complete(complete_rb);
	}
eoi:
	return;
}

void *ishtp_get_client_data(struct ishtp_cl *cl)
{
	return cl->client_data;
}
EXPORT_SYMBOL(ishtp_get_client_data);

void ishtp_set_client_data(struct ishtp_cl *cl, void *data)
{
	cl->client_data = data;
}
EXPORT_SYMBOL(ishtp_set_client_data);

struct ishtp_device *ishtp_get_ishtp_device(struct ishtp_cl *cl)
{
	return cl->dev;
}
EXPORT_SYMBOL(ishtp_get_ishtp_device);

void ishtp_set_tx_ring_size(struct ishtp_cl *cl, int size)
{
	cl->tx_ring_size = size;
}
EXPORT_SYMBOL(ishtp_set_tx_ring_size);

void ishtp_set_rx_ring_size(struct ishtp_cl *cl, int size)
{
	cl->rx_ring_size = size;
}
EXPORT_SYMBOL(ishtp_set_rx_ring_size);

void ishtp_set_connection_state(struct ishtp_cl *cl, int state)
{
	cl->state = state;
}
EXPORT_SYMBOL(ishtp_set_connection_state);

void ishtp_cl_set_fw_client_id(struct ishtp_cl *cl, int fw_client_id)
{
	cl->fw_client_id = fw_client_id;
}
EXPORT_SYMBOL(ishtp_cl_set_fw_client_id);