aboutsummaryrefslogtreecommitdiff
path: root/drivers/rpmsg/qcom_glink_native.c
blob: ffdf88e436a7296c16cea632545d0976d7ff456f (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
/*
 * Copyright (c) 2016-2017, Linaro Ltd
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/idr.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/rpmsg.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/mailbox_client.h>

#include "rpmsg_internal.h"
#include "qcom_glink_native.h"

#define GLINK_NAME_SIZE		32

#define RPM_GLINK_CID_MIN	1
#define RPM_GLINK_CID_MAX	65536

struct glink_msg {
	__le16 cmd;
	__le16 param1;
	__le32 param2;
	u8 data[];
} __packed;

/**
 * struct glink_defer_cmd - deferred incoming control message
 * @node:	list node
 * @msg:	message header
 * data:	payload of the message
 *
 * Copy of a received control message, to be added to @rx_queue and processed
 * by @rx_work of @qcom_glink.
 */
struct glink_defer_cmd {
	struct list_head node;

	struct glink_msg msg;
	u8 data[];
};

/**
 * struct qcom_glink - driver context, relates to one remote subsystem
 * @dev:	reference to the associated struct device
 * @mbox_client: mailbox client
 * @mbox_chan:  mailbox channel
 * @rx_pipe:	pipe object for receive FIFO
 * @tx_pipe:	pipe object for transmit FIFO
 * @irq:	IRQ for signaling incoming events
 * @rx_work:	worker for handling received control messages
 * @rx_lock:	protects the @rx_queue
 * @rx_queue:	queue of received control messages to be processed in @rx_work
 * @tx_lock:	synchronizes operations on the tx fifo
 * @idr_lock:	synchronizes @lcids and @rcids modifications
 * @lcids:	idr of all channels with a known local channel id
 * @rcids:	idr of all channels with a known remote channel id
 */
struct qcom_glink {
	struct device *dev;

	struct mbox_client mbox_client;
	struct mbox_chan *mbox_chan;

	struct qcom_glink_pipe *rx_pipe;
	struct qcom_glink_pipe *tx_pipe;

	int irq;

	struct work_struct rx_work;
	spinlock_t rx_lock;
	struct list_head rx_queue;

	struct mutex tx_lock;

	struct mutex idr_lock;
	struct idr lcids;
	struct idr rcids;
};

enum {
	GLINK_STATE_CLOSED,
	GLINK_STATE_OPENING,
	GLINK_STATE_OPEN,
	GLINK_STATE_CLOSING,
};

/**
 * struct glink_channel - internal representation of a channel
 * @rpdev:	rpdev reference, only used for primary endpoints
 * @ept:	rpmsg endpoint this channel is associated with
 * @glink:	qcom_glink context handle
 * @refcount:	refcount for the channel object
 * @recv_lock:	guard for @ept.cb
 * @name:	unique channel name/identifier
 * @lcid:	channel id, in local space
 * @rcid:	channel id, in remote space
 * @buf:	receive buffer, for gathering fragments
 * @buf_offset:	write offset in @buf
 * @buf_size:	size of current @buf
 * @open_ack:	completed once remote has acked the open-request
 * @open_req:	completed once open-request has been received
 */
struct glink_channel {
	struct rpmsg_endpoint ept;

	struct rpmsg_device *rpdev;
	struct qcom_glink *glink;

	struct kref refcount;

	spinlock_t recv_lock;

	char *name;
	unsigned int lcid;
	unsigned int rcid;

	void *buf;
	int buf_offset;
	int buf_size;

	struct completion open_ack;
	struct completion open_req;
};

#define to_glink_channel(_ept) container_of(_ept, struct glink_channel, ept)

static const struct rpmsg_endpoint_ops glink_endpoint_ops;

#define RPM_CMD_VERSION			0
#define RPM_CMD_VERSION_ACK		1
#define RPM_CMD_OPEN			2
#define RPM_CMD_CLOSE			3
#define RPM_CMD_OPEN_ACK		4
#define RPM_CMD_TX_DATA			9
#define RPM_CMD_CLOSE_ACK		11
#define RPM_CMD_TX_DATA_CONT		12
#define RPM_CMD_READ_NOTIF		13

#define GLINK_FEATURE_INTENTLESS	BIT(1)

static struct glink_channel *qcom_glink_alloc_channel(struct qcom_glink *glink,
						      const char *name)
{
	struct glink_channel *channel;

	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
	if (!channel)
		return ERR_PTR(-ENOMEM);

	/* Setup glink internal glink_channel data */
	spin_lock_init(&channel->recv_lock);
	channel->glink = glink;
	channel->name = kstrdup(name, GFP_KERNEL);

	init_completion(&channel->open_req);
	init_completion(&channel->open_ack);

	kref_init(&channel->refcount);

	return channel;
}

static void qcom_glink_channel_release(struct kref *ref)
{
	struct glink_channel *channel = container_of(ref, struct glink_channel,
						     refcount);

	kfree(channel->name);
	kfree(channel);
}

static size_t qcom_glink_rx_avail(struct qcom_glink *glink)
{
	return glink->rx_pipe->avail(glink->rx_pipe);
}

static void qcom_glink_rx_peak(struct qcom_glink *glink,
			       void *data, size_t count)
{
	glink->rx_pipe->peak(glink->rx_pipe, data, count);
}

static void qcom_glink_rx_advance(struct qcom_glink *glink, size_t count)
{
	glink->rx_pipe->advance(glink->rx_pipe, count);
}

static size_t qcom_glink_tx_avail(struct qcom_glink *glink)
{
	return glink->tx_pipe->avail(glink->tx_pipe);
}

static void qcom_glink_tx_write(struct qcom_glink *glink,
				const void *hdr, size_t hlen,
				const void *data, size_t dlen)
{
	glink->tx_pipe->write(glink->tx_pipe, hdr, hlen, data, dlen);
}

static int qcom_glink_tx(struct qcom_glink *glink,
			 const void *hdr, size_t hlen,
			 const void *data, size_t dlen, bool wait)
{
	unsigned int tlen = hlen + dlen;
	int ret;

	/* Reject packets that are too big */
	if (tlen >= glink->tx_pipe->length)
		return -EINVAL;

	if (WARN(tlen % 8, "Unaligned TX request"))
		return -EINVAL;

	ret = mutex_lock_interruptible(&glink->tx_lock);
	if (ret)
		return ret;

	while (qcom_glink_tx_avail(glink) < tlen) {
		if (!wait) {
			ret = -ENOMEM;
			goto out;
		}

		usleep_range(10000, 15000);
	}

	qcom_glink_tx_write(glink, hdr, hlen, data, dlen);

	mbox_send_message(glink->mbox_chan, NULL);
	mbox_client_txdone(glink->mbox_chan, 0);

out:
	mutex_unlock(&glink->tx_lock);

	return ret;
}

static int qcom_glink_send_version(struct qcom_glink *glink)
{
	struct glink_msg msg;

	msg.cmd = cpu_to_le16(RPM_CMD_VERSION);
	msg.param1 = cpu_to_le16(1);
	msg.param2 = cpu_to_le32(GLINK_FEATURE_INTENTLESS);

	return qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
}

static void qcom_glink_send_version_ack(struct qcom_glink *glink)
{
	struct glink_msg msg;

	msg.cmd = cpu_to_le16(RPM_CMD_VERSION_ACK);
	msg.param1 = cpu_to_le16(1);
	msg.param2 = cpu_to_le32(0);

	qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
}

static void qcom_glink_send_open_ack(struct qcom_glink *glink,
				     struct glink_channel *channel)
{
	struct glink_msg msg;

	msg.cmd = cpu_to_le16(RPM_CMD_OPEN_ACK);
	msg.param1 = cpu_to_le16(channel->rcid);
	msg.param2 = cpu_to_le32(0);

	qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
}

/**
 * qcom_glink_send_open_req() - send a RPM_CMD_OPEN request to the remote
 * @glink: Ptr to the glink edge
 * @channel: Ptr to the channel that the open req is sent
 *
 * Allocates a local channel id and sends a RPM_CMD_OPEN message to the remote.
 * Will return with refcount held, regardless of outcome.
 *
 * Returns 0 on success, negative errno otherwise.
 */
static int qcom_glink_send_open_req(struct qcom_glink *glink,
				    struct glink_channel *channel)
{
	struct {
		struct glink_msg msg;
		u8 name[GLINK_NAME_SIZE];
	} __packed req;
	int name_len = strlen(channel->name) + 1;
	int req_len = ALIGN(sizeof(req.msg) + name_len, 8);
	int ret;

	kref_get(&channel->refcount);

	mutex_lock(&glink->idr_lock);
	ret = idr_alloc_cyclic(&glink->lcids, channel,
			       RPM_GLINK_CID_MIN, RPM_GLINK_CID_MAX,
			       GFP_KERNEL);
	mutex_unlock(&glink->idr_lock);
	if (ret < 0)
		return ret;

	channel->lcid = ret;

	req.msg.cmd = cpu_to_le16(RPM_CMD_OPEN);
	req.msg.param1 = cpu_to_le16(channel->lcid);
	req.msg.param2 = cpu_to_le32(name_len);
	strcpy(req.name, channel->name);

	ret = qcom_glink_tx(glink, &req, req_len, NULL, 0, true);
	if (ret)
		goto remove_idr;

	return 0;

remove_idr:
	mutex_lock(&glink->idr_lock);
	idr_remove(&glink->lcids, channel->lcid);
	channel->lcid = 0;
	mutex_unlock(&glink->idr_lock);

	return ret;
}

static void qcom_glink_send_close_req(struct qcom_glink *glink,
				      struct glink_channel *channel)
{
	struct glink_msg req;

	req.cmd = cpu_to_le16(RPM_CMD_CLOSE);
	req.param1 = cpu_to_le16(channel->lcid);
	req.param2 = 0;

	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
}

static void qcom_glink_send_close_ack(struct qcom_glink *glink,
				      unsigned int rcid)
{
	struct glink_msg req;

	req.cmd = cpu_to_le16(RPM_CMD_CLOSE_ACK);
	req.param1 = cpu_to_le16(rcid);
	req.param2 = 0;

	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
}

static int qcom_glink_rx_defer(struct qcom_glink *glink, size_t extra)
{
	struct glink_defer_cmd *dcmd;

	extra = ALIGN(extra, 8);

	if (qcom_glink_rx_avail(glink) < sizeof(struct glink_msg) + extra) {
		dev_dbg(glink->dev, "Insufficient data in rx fifo");
		return -ENXIO;
	}

	dcmd = kzalloc(sizeof(*dcmd) + extra, GFP_ATOMIC);
	if (!dcmd)
		return -ENOMEM;

	INIT_LIST_HEAD(&dcmd->node);

	qcom_glink_rx_peak(glink, &dcmd->msg, sizeof(dcmd->msg) + extra);

	spin_lock(&glink->rx_lock);
	list_add_tail(&dcmd->node, &glink->rx_queue);
	spin_unlock(&glink->rx_lock);

	schedule_work(&glink->rx_work);
	qcom_glink_rx_advance(glink, sizeof(dcmd->msg) + extra);

	return 0;
}

static int qcom_glink_rx_data(struct qcom_glink *glink, size_t avail)
{
	struct glink_channel *channel;
	struct {
		struct glink_msg msg;
		__le32 chunk_size;
		__le32 left_size;
	} __packed hdr;
	unsigned int chunk_size;
	unsigned int left_size;
	unsigned int rcid;

	if (avail < sizeof(hdr)) {
		dev_dbg(glink->dev, "Not enough data in fifo\n");
		return -EAGAIN;
	}

	qcom_glink_rx_peak(glink, &hdr, sizeof(hdr));
	chunk_size = le32_to_cpu(hdr.chunk_size);
	left_size = le32_to_cpu(hdr.left_size);

	if (avail < sizeof(hdr) + chunk_size) {
		dev_dbg(glink->dev, "Payload not yet in fifo\n");
		return -EAGAIN;
	}

	if (WARN(chunk_size % 4, "Incoming data must be word aligned\n"))
		return -EINVAL;

	rcid = le16_to_cpu(hdr.msg.param1);
	channel = idr_find(&glink->rcids, rcid);
	if (!channel) {
		dev_dbg(glink->dev, "Data on non-existing channel\n");

		/* Drop the message */
		qcom_glink_rx_advance(glink,
				      ALIGN(sizeof(hdr) + chunk_size, 8));
		return 0;
	}

	/* Might have an ongoing, fragmented, message to append */
	if (!channel->buf) {
		channel->buf = kmalloc(chunk_size + left_size, GFP_ATOMIC);
		if (!channel->buf)
			return -ENOMEM;

		channel->buf_size = chunk_size + left_size;
		channel->buf_offset = 0;
	}

	qcom_glink_rx_advance(glink, sizeof(hdr));

	if (channel->buf_size - channel->buf_offset < chunk_size) {
		dev_err(glink->dev, "Insufficient space in input buffer\n");

		/* The packet header lied, drop payload */
		qcom_glink_rx_advance(glink, chunk_size);
		return -ENOMEM;
	}

	qcom_glink_rx_peak(glink, channel->buf + channel->buf_offset,
			   chunk_size);
	channel->buf_offset += chunk_size;

	/* Handle message when no fragments remain to be received */
	if (!left_size) {
		spin_lock(&channel->recv_lock);
		if (channel->ept.cb) {
			channel->ept.cb(channel->ept.rpdev,
					channel->buf,
					channel->buf_offset,
					channel->ept.priv,
					RPMSG_ADDR_ANY);
		}
		spin_unlock(&channel->recv_lock);

		kfree(channel->buf);
		channel->buf = NULL;
		channel->buf_size = 0;
	}

	/* Each message starts at 8 byte aligned address */
	qcom_glink_rx_advance(glink, ALIGN(chunk_size, 8));

	return 0;
}

static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)
{
	struct glink_channel *channel;

	channel = idr_find(&glink->lcids, lcid);
	if (!channel) {
		dev_err(glink->dev, "Invalid open ack packet\n");
		return -EINVAL;
	}

	complete(&channel->open_ack);

	return 0;
}

static irqreturn_t qcom_glink_native_intr(int irq, void *data)
{
	struct qcom_glink *glink = data;
	struct glink_msg msg;
	unsigned int param1;
	unsigned int param2;
	unsigned int avail;
	unsigned int cmd;
	int ret;

	for (;;) {
		avail = qcom_glink_rx_avail(glink);
		if (avail < sizeof(msg))
			break;

		qcom_glink_rx_peak(glink, &msg, sizeof(msg));

		cmd = le16_to_cpu(msg.cmd);
		param1 = le16_to_cpu(msg.param1);
		param2 = le32_to_cpu(msg.param2);

		switch (cmd) {
		case RPM_CMD_VERSION:
		case RPM_CMD_VERSION_ACK:
		case RPM_CMD_CLOSE:
		case RPM_CMD_CLOSE_ACK:
			ret = qcom_glink_rx_defer(glink, 0);
			break;
		case RPM_CMD_OPEN_ACK:
			ret = qcom_glink_rx_open_ack(glink, param1);
			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
			break;
		case RPM_CMD_OPEN:
			ret = qcom_glink_rx_defer(glink, param2);
			break;
		case RPM_CMD_TX_DATA:
		case RPM_CMD_TX_DATA_CONT:
			ret = qcom_glink_rx_data(glink, avail);
			break;
		case RPM_CMD_READ_NOTIF:
			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));

			mbox_send_message(glink->mbox_chan, NULL);
			mbox_client_txdone(glink->mbox_chan, 0);

			ret = 0;
			break;
		default:
			dev_err(glink->dev, "unhandled rx cmd: %d\n", cmd);
			ret = -EINVAL;
			break;
		}

		if (ret)
			break;
	}

	return IRQ_HANDLED;
}

/* Locally initiated rpmsg_create_ept */
static struct glink_channel *qcom_glink_create_local(struct qcom_glink *glink,
						     const char *name)
{
	struct glink_channel *channel;
	int ret;

	channel = qcom_glink_alloc_channel(glink, name);
	if (IS_ERR(channel))
		return ERR_CAST(channel);

	ret = qcom_glink_send_open_req(glink, channel);
	if (ret)
		goto release_channel;

	ret = wait_for_completion_timeout(&channel->open_ack, 5 * HZ);
	if (!ret)
		goto err_timeout;

	ret = wait_for_completion_timeout(&channel->open_req, 5 * HZ);
	if (!ret)
		goto err_timeout;

	qcom_glink_send_open_ack(glink, channel);

	return channel;

err_timeout:
	/* qcom_glink_send_open_req() did register the channel in lcids*/
	mutex_lock(&glink->idr_lock);
	idr_remove(&glink->lcids, channel->lcid);
	mutex_unlock(&glink->idr_lock);

release_channel:
	/* Release qcom_glink_send_open_req() reference */
	kref_put(&channel->refcount, qcom_glink_channel_release);
	/* Release qcom_glink_alloc_channel() reference */
	kref_put(&channel->refcount, qcom_glink_channel_release);

	return ERR_PTR(-ETIMEDOUT);
}

/* Remote initiated rpmsg_create_ept */
static int qcom_glink_create_remote(struct qcom_glink *glink,
				    struct glink_channel *channel)
{
	int ret;

	qcom_glink_send_open_ack(glink, channel);

	ret = qcom_glink_send_open_req(glink, channel);
	if (ret)
		goto close_link;

	ret = wait_for_completion_timeout(&channel->open_ack, 5 * HZ);
	if (!ret) {
		ret = -ETIMEDOUT;
		goto close_link;
	}

	return 0;

close_link:
	/*
	 * Send a close request to "undo" our open-ack. The close-ack will
	 * release the last reference.
	 */
	qcom_glink_send_close_req(glink, channel);

	/* Release qcom_glink_send_open_req() reference */
	kref_put(&channel->refcount, qcom_glink_channel_release);

	return ret;
}

static struct rpmsg_endpoint *qcom_glink_create_ept(struct rpmsg_device *rpdev,
						    rpmsg_rx_cb_t cb,
						    void *priv,
						    struct rpmsg_channel_info
									chinfo)
{
	struct glink_channel *parent = to_glink_channel(rpdev->ept);
	struct glink_channel *channel;
	struct qcom_glink *glink = parent->glink;
	struct rpmsg_endpoint *ept;
	const char *name = chinfo.name;
	int cid;
	int ret;

	idr_for_each_entry(&glink->rcids, channel, cid) {
		if (!strcmp(channel->name, name))
			break;
	}

	if (!channel) {
		channel = qcom_glink_create_local(glink, name);
		if (IS_ERR(channel))
			return NULL;
	} else {
		ret = qcom_glink_create_remote(glink, channel);
		if (ret)
			return NULL;
	}

	ept = &channel->ept;
	ept->rpdev = rpdev;
	ept->cb = cb;
	ept->priv = priv;
	ept->ops = &glink_endpoint_ops;

	return ept;
}

static void qcom_glink_destroy_ept(struct rpmsg_endpoint *ept)
{
	struct glink_channel *channel = to_glink_channel(ept);
	struct qcom_glink *glink = channel->glink;
	unsigned long flags;

	spin_lock_irqsave(&channel->recv_lock, flags);
	channel->ept.cb = NULL;
	spin_unlock_irqrestore(&channel->recv_lock, flags);

	/* Decouple the potential rpdev from the channel */
	channel->rpdev = NULL;

	qcom_glink_send_close_req(glink, channel);
}

static int __qcom_glink_send(struct glink_channel *channel,
			     void *data, int len, bool wait)
{
	struct qcom_glink *glink = channel->glink;
	struct {
		struct glink_msg msg;
		__le32 chunk_size;
		__le32 left_size;
	} __packed req;

	if (WARN(len % 8, "RPM GLINK expects 8 byte aligned messages\n"))
		return -EINVAL;

	req.msg.cmd = cpu_to_le16(RPM_CMD_TX_DATA);
	req.msg.param1 = cpu_to_le16(channel->lcid);
	req.msg.param2 = cpu_to_le32(channel->rcid);
	req.chunk_size = cpu_to_le32(len);
	req.left_size = cpu_to_le32(0);

	return qcom_glink_tx(glink, &req, sizeof(req), data, len, wait);
}

static int qcom_glink_send(struct rpmsg_endpoint *ept, void *data, int len)
{
	struct glink_channel *channel = to_glink_channel(ept);

	return __qcom_glink_send(channel, data, len, true);
}

static int qcom_glink_trysend(struct rpmsg_endpoint *ept, void *data, int len)
{
	struct glink_channel *channel = to_glink_channel(ept);

	return __qcom_glink_send(channel, data, len, false);
}

/*
 * Finds the device_node for the glink child interested in this channel.
 */
static struct device_node *qcom_glink_match_channel(struct device_node *node,
						    const char *channel)
{
	struct device_node *child;
	const char *name;
	const char *key;
	int ret;

	for_each_available_child_of_node(node, child) {
		key = "qcom,glink-channels";
		ret = of_property_read_string(child, key, &name);
		if (ret)
			continue;

		if (strcmp(name, channel) == 0)
			return child;
	}

	return NULL;
}

static const struct rpmsg_device_ops glink_device_ops = {
	.create_ept = qcom_glink_create_ept,
};

static const struct rpmsg_endpoint_ops glink_endpoint_ops = {
	.destroy_ept = qcom_glink_destroy_ept,
	.send = qcom_glink_send,
	.trysend = qcom_glink_trysend,
};

static void qcom_glink_rpdev_release(struct device *dev)
{
	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
	struct glink_channel *channel = to_glink_channel(rpdev->ept);

	channel->rpdev = NULL;
	kfree(rpdev);
}

static int qcom_glink_rx_open(struct qcom_glink *glink, unsigned int rcid,
			      char *name)
{
	struct glink_channel *channel;
	struct rpmsg_device *rpdev;
	bool create_device = false;
	struct device_node *node;
	int lcid;
	int ret;

	idr_for_each_entry(&glink->lcids, channel, lcid) {
		if (!strcmp(channel->name, name))
			break;
	}

	if (!channel) {
		channel = qcom_glink_alloc_channel(glink, name);
		if (IS_ERR(channel))
			return PTR_ERR(channel);

		/* The opening dance was initiated by the remote */
		create_device = true;
	}

	mutex_lock(&glink->idr_lock);
	ret = idr_alloc(&glink->rcids, channel, rcid, rcid + 1, GFP_KERNEL);
	if (ret < 0) {
		dev_err(glink->dev, "Unable to insert channel into rcid list\n");
		mutex_unlock(&glink->idr_lock);
		goto free_channel;
	}
	channel->rcid = ret;
	mutex_unlock(&glink->idr_lock);

	complete(&channel->open_req);

	if (create_device) {
		rpdev = kzalloc(sizeof(*rpdev), GFP_KERNEL);
		if (!rpdev) {
			ret = -ENOMEM;
			goto rcid_remove;
		}

		rpdev->ept = &channel->ept;
		strncpy(rpdev->id.name, name, RPMSG_NAME_SIZE);
		rpdev->src = RPMSG_ADDR_ANY;
		rpdev->dst = RPMSG_ADDR_ANY;
		rpdev->ops = &glink_device_ops;

		node = qcom_glink_match_channel(glink->dev->of_node, name);
		rpdev->dev.of_node = node;
		rpdev->dev.parent = glink->dev;
		rpdev->dev.release = qcom_glink_rpdev_release;

		ret = rpmsg_register_device(rpdev);
		if (ret)
			goto free_rpdev;

		channel->rpdev = rpdev;
	}

	return 0;

free_rpdev:
	kfree(rpdev);
rcid_remove:
	mutex_lock(&glink->idr_lock);
	idr_remove(&glink->rcids, channel->rcid);
	channel->rcid = 0;
	mutex_unlock(&glink->idr_lock);
free_channel:
	/* Release the reference, iff we took it */
	if (create_device)
		kref_put(&channel->refcount, qcom_glink_channel_release);

	return ret;
}

static void qcom_glink_rx_close(struct qcom_glink *glink, unsigned int rcid)
{
	struct rpmsg_channel_info chinfo;
	struct glink_channel *channel;

	channel = idr_find(&glink->rcids, rcid);
	if (WARN(!channel, "close request on unknown channel\n"))
		return;

	if (channel->rpdev) {
		strncpy(chinfo.name, channel->name, sizeof(chinfo.name));
		chinfo.src = RPMSG_ADDR_ANY;
		chinfo.dst = RPMSG_ADDR_ANY;

		rpmsg_unregister_device(glink->dev, &chinfo);
	}

	qcom_glink_send_close_ack(glink, channel->rcid);

	mutex_lock(&glink->idr_lock);
	idr_remove(&glink->rcids, channel->rcid);
	channel->rcid = 0;
	mutex_unlock(&glink->idr_lock);

	kref_put(&channel->refcount, qcom_glink_channel_release);
}

static void qcom_glink_rx_close_ack(struct qcom_glink *glink, unsigned int lcid)
{
	struct glink_channel *channel;

	channel = idr_find(&glink->lcids, lcid);
	if (WARN(!channel, "close ack on unknown channel\n"))
		return;

	mutex_lock(&glink->idr_lock);
	idr_remove(&glink->lcids, channel->lcid);
	channel->lcid = 0;
	mutex_unlock(&glink->idr_lock);

	kref_put(&channel->refcount, qcom_glink_channel_release);
}

static void qcom_glink_work(struct work_struct *work)
{
	struct qcom_glink *glink = container_of(work, struct qcom_glink,
						rx_work);
	struct glink_defer_cmd *dcmd;
	struct glink_msg *msg;
	unsigned long flags;
	unsigned int param1;
	unsigned int param2;
	unsigned int cmd;

	for (;;) {
		spin_lock_irqsave(&glink->rx_lock, flags);
		if (list_empty(&glink->rx_queue)) {
			spin_unlock_irqrestore(&glink->rx_lock, flags);
			break;
		}
		dcmd = list_first_entry(&glink->rx_queue,
					struct glink_defer_cmd, node);
		list_del(&dcmd->node);
		spin_unlock_irqrestore(&glink->rx_lock, flags);

		msg = &dcmd->msg;
		cmd = le16_to_cpu(msg->cmd);
		param1 = le16_to_cpu(msg->param1);
		param2 = le32_to_cpu(msg->param2);

		switch (cmd) {
		case RPM_CMD_VERSION:
			qcom_glink_send_version_ack(glink);
			break;
		case RPM_CMD_VERSION_ACK:
			break;
		case RPM_CMD_OPEN:
			qcom_glink_rx_open(glink, param1, msg->data);
			break;
		case RPM_CMD_CLOSE:
			qcom_glink_rx_close(glink, param1);
			break;
		case RPM_CMD_CLOSE_ACK:
			qcom_glink_rx_close_ack(glink, param1);
			break;
		default:
			WARN(1, "Unknown defer object %d\n", cmd);
			break;
		}

		kfree(dcmd);
	}
}

struct qcom_glink *qcom_glink_native_probe(struct device *dev,
					   struct qcom_glink_pipe *rx,
					   struct qcom_glink_pipe *tx)
{
	int irq;
	int ret;
	struct qcom_glink *glink;

	glink = devm_kzalloc(dev, sizeof(*glink), GFP_KERNEL);
	if (!glink)
		return ERR_PTR(-ENOMEM);

	glink->dev = dev;
	glink->tx_pipe = tx;
	glink->rx_pipe = rx;

	mutex_init(&glink->tx_lock);
	spin_lock_init(&glink->rx_lock);
	INIT_LIST_HEAD(&glink->rx_queue);
	INIT_WORK(&glink->rx_work, qcom_glink_work);

	mutex_init(&glink->idr_lock);
	idr_init(&glink->lcids);
	idr_init(&glink->rcids);

	glink->mbox_client.dev = dev;
	glink->mbox_chan = mbox_request_channel(&glink->mbox_client, 0);
	if (IS_ERR(glink->mbox_chan)) {
		if (PTR_ERR(glink->mbox_chan) != -EPROBE_DEFER)
			dev_err(dev, "failed to acquire IPC channel\n");
		return ERR_CAST(glink->mbox_chan);
	}

	irq = of_irq_get(dev->of_node, 0);
	ret = devm_request_irq(dev, irq,
			       qcom_glink_native_intr,
			       IRQF_NO_SUSPEND | IRQF_SHARED,
			       "glink-native", glink);
	if (ret) {
		dev_err(dev, "failed to request IRQ\n");
		return ERR_PTR(ret);
	}

	glink->irq = irq;

	ret = qcom_glink_send_version(glink);
	if (ret)
		return ERR_PTR(ret);

	return glink;
}

static int qcom_glink_remove_device(struct device *dev, void *data)
{
	device_unregister(dev);

	return 0;
}

void qcom_glink_native_remove(struct qcom_glink *glink)
{
	struct glink_channel *channel;
	int cid;
	int ret;

	disable_irq(glink->irq);
	cancel_work_sync(&glink->rx_work);

	ret = device_for_each_child(glink->dev, NULL, qcom_glink_remove_device);
	if (ret)
		dev_warn(glink->dev, "Can't remove GLINK devices: %d\n", ret);

	/* Release any defunct local channels, waiting for close-ack */
	idr_for_each_entry(&glink->lcids, channel, cid)
		kref_put(&channel->refcount, qcom_glink_channel_release);

	idr_destroy(&glink->lcids);
	idr_destroy(&glink->rcids);
}