summaryrefslogtreecommitdiffstats
path: root/drivers/rpmsg/qcom_glink_native.c
blob: 82d460ff477718e5a847401186e8b7ca6e4fbe7a (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
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2016-2017, Linaro Ltd
 */

#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/platform_device.h>
#include <linux/regmap.h>
#include <linux/rpmsg.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/wait.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 GLINK_VERSION_1		1

#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 glink_core_rx_intent - RX intent
 * RX intent
 *
 * @data: pointer to the data (may be NULL for zero-copy)
 * @id: remote or local intent ID
 * @size: size of the original intent (do not modify)
 * @reuse: To mark if the intent can be reused after first use
 * @in_use: To mark if intent is already in use for the channel
 * @offset: next write offset (initially 0)
 * @node:	list node
 */
struct glink_core_rx_intent {
	void *data;
	u32 id;
	size_t size;
	bool reuse;
	bool in_use;
	u32 offset;

	struct list_head node;
};

/**
 * struct qcom_glink - driver context, relates to one remote subsystem
 * @dev:	reference to the associated struct device
 * @rx_pipe:	pipe object for receive FIFO
 * @tx_pipe:	pipe object for transmit FIFO
 * @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
 * @features:	remote features
 * @intentless:	flag to indicate that there is no intent
 * @tx_avail_notify: Waitqueue for pending tx tasks
 * @sent_read_notify: flag to check cmd sent or not
 * @abort_tx:	flag indicating that all tx attempts should fail
 */
struct qcom_glink {
	struct device *dev;

	struct qcom_glink_pipe *rx_pipe;
	struct qcom_glink_pipe *tx_pipe;

	struct work_struct rx_work;
	spinlock_t rx_lock;
	struct list_head rx_queue;

	spinlock_t tx_lock;

	spinlock_t idr_lock;
	struct idr lcids;
	struct idr rcids;
	unsigned long features;

	bool intentless;
	wait_queue_head_t tx_avail_notify;
	bool sent_read_notify;

	bool abort_tx;
};

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
 * @intent_lock: lock for protection of @liids, @riids
 * @liids:	idr of all local intents
 * @riids:	idr of all remote intents
 * @intent_work: worker responsible for transmitting rx_done packets
 * @done_intents: list of intents that needs to be announced rx_done
 * @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
 * @intent_req_lock: Synchronises multiple intent requests
 * @intent_req_result: Result of intent request
 * @intent_received: flag indicating that an intent has been received
 * @intent_req_wq: wait queue for intent_req signalling
 */
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;

	spinlock_t intent_lock;
	struct idr liids;
	struct idr riids;
	struct work_struct intent_work;
	struct list_head done_intents;

	struct glink_core_rx_intent *buf;
	int buf_offset;
	int buf_size;

	struct completion open_ack;
	struct completion open_req;

	struct mutex intent_req_lock;
	int intent_req_result;
	bool intent_received;
	wait_queue_head_t intent_req_wq;
};

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

static const struct rpmsg_endpoint_ops glink_endpoint_ops;

#define GLINK_CMD_VERSION		0
#define GLINK_CMD_VERSION_ACK		1
#define GLINK_CMD_OPEN			2
#define GLINK_CMD_CLOSE			3
#define GLINK_CMD_OPEN_ACK		4
#define GLINK_CMD_INTENT		5
#define GLINK_CMD_RX_DONE		6
#define GLINK_CMD_RX_INTENT_REQ		7
#define GLINK_CMD_RX_INTENT_REQ_ACK	8
#define GLINK_CMD_TX_DATA		9
#define GLINK_CMD_CLOSE_ACK		11
#define GLINK_CMD_TX_DATA_CONT		12
#define GLINK_CMD_READ_NOTIF		13
#define GLINK_CMD_RX_DONE_W_REUSE	14
#define GLINK_CMD_SIGNALS		15

#define GLINK_FEATURE_INTENTLESS	BIT(1)

#define NATIVE_DTR_SIG			NATIVE_DSR_SIG
#define NATIVE_DSR_SIG			BIT(31)
#define NATIVE_RTS_SIG			NATIVE_CTS_SIG
#define NATIVE_CTS_SIG			BIT(30)

static void qcom_glink_rx_done_work(struct work_struct *work);

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);
	spin_lock_init(&channel->intent_lock);
	mutex_init(&channel->intent_req_lock);

	channel->glink = glink;
	channel->name = kstrdup(name, GFP_KERNEL);
	if (!channel->name) {
		kfree(channel);
		return ERR_PTR(-ENOMEM);
	}

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

	INIT_LIST_HEAD(&channel->done_intents);
	INIT_WORK(&channel->intent_work, qcom_glink_rx_done_work);

	idr_init(&channel->liids);
	idr_init(&channel->riids);
	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);
	struct glink_core_rx_intent *intent;
	struct glink_core_rx_intent *tmp;
	unsigned long flags;
	int iid;

	/* cancel pending rx_done work */
	cancel_work_sync(&channel->intent_work);

	spin_lock_irqsave(&channel->intent_lock, flags);
	/* Free all non-reuse intents pending rx_done work */
	list_for_each_entry_safe(intent, tmp, &channel->done_intents, node) {
		if (!intent->reuse) {
			kfree(intent->data);
			kfree(intent);
		}
	}

	idr_for_each_entry(&channel->liids, tmp, iid) {
		kfree(tmp->data);
		kfree(tmp);
	}
	idr_destroy(&channel->liids);

	idr_for_each_entry(&channel->riids, tmp, iid)
		kfree(tmp);
	idr_destroy(&channel->riids);
	spin_unlock_irqrestore(&channel->intent_lock, flags);

	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_peek(struct qcom_glink *glink,
			       void *data, unsigned int offset, size_t count)
{
	glink->rx_pipe->peek(glink->rx_pipe, data, offset, 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 void qcom_glink_tx_kick(struct qcom_glink *glink)
{
	glink->tx_pipe->kick(glink->tx_pipe);
}

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

	msg.cmd = cpu_to_le16(GLINK_CMD_READ_NOTIF);
	msg.param1 = 0;
	msg.param2 = 0;

	qcom_glink_tx_write(glink, &msg, sizeof(msg), NULL, 0);

	qcom_glink_tx_kick(glink);
}

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;
	unsigned long flags;
	int ret = 0;

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

	spin_lock_irqsave(&glink->tx_lock, flags);

	if (glink->abort_tx) {
		ret = -EIO;
		goto out;
	}

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

		if (glink->abort_tx) {
			ret = -EIO;
			goto out;
		}

		if (!glink->sent_read_notify) {
			glink->sent_read_notify = true;
			qcom_glink_send_read_notify(glink);
		}

		/* Wait without holding the tx_lock */
		spin_unlock_irqrestore(&glink->tx_lock, flags);

		wait_event_timeout(glink->tx_avail_notify,
				   qcom_glink_tx_avail(glink) >= tlen, 10 * HZ);

		spin_lock_irqsave(&glink->tx_lock, flags);

		if (qcom_glink_tx_avail(glink) >= tlen)
			glink->sent_read_notify = false;
	}

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

out:
	spin_unlock_irqrestore(&glink->tx_lock, flags);

	return ret;
}

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

	msg.cmd = cpu_to_le16(GLINK_CMD_VERSION);
	msg.param1 = cpu_to_le16(GLINK_VERSION_1);
	msg.param2 = cpu_to_le32(glink->features);

	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(GLINK_CMD_VERSION_ACK);
	msg.param1 = cpu_to_le16(GLINK_VERSION_1);
	msg.param2 = cpu_to_le32(glink->features);

	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(GLINK_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);
}

static void qcom_glink_handle_intent_req_ack(struct qcom_glink *glink,
					     unsigned int cid, bool granted)
{
	struct glink_channel *channel;
	unsigned long flags;

	spin_lock_irqsave(&glink->idr_lock, flags);
	channel = idr_find(&glink->rcids, cid);
	spin_unlock_irqrestore(&glink->idr_lock, flags);
	if (!channel) {
		dev_err(glink->dev, "unable to find channel\n");
		return;
	}

	WRITE_ONCE(channel->intent_req_result, granted);
	wake_up_all(&channel->intent_req_wq);
}

static void qcom_glink_intent_req_abort(struct glink_channel *channel)
{
	WRITE_ONCE(channel->intent_req_result, 0);
	wake_up_all(&channel->intent_req_wq);
}

/**
 * qcom_glink_send_open_req() - send a GLINK_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 GLINK_CMD_OPEN message to the remote.
 * Will return with refcount held, regardless of outcome.
 *
 * Return: 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;
	unsigned long flags;

	kref_get(&channel->refcount);

	spin_lock_irqsave(&glink->idr_lock, flags);
	ret = idr_alloc_cyclic(&glink->lcids, channel,
			       RPM_GLINK_CID_MIN, RPM_GLINK_CID_MAX,
			       GFP_ATOMIC);
	spin_unlock_irqrestore(&glink->idr_lock, flags);
	if (ret < 0)
		return ret;

	channel->lcid = ret;

	req.msg.cmd = cpu_to_le16(GLINK_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:
	spin_lock_irqsave(&glink->idr_lock, flags);
	idr_remove(&glink->lcids, channel->lcid);
	channel->lcid = 0;
	spin_unlock_irqrestore(&glink->idr_lock, flags);

	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(GLINK_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(GLINK_CMD_CLOSE_ACK);
	req.param1 = cpu_to_le16(rcid);
	req.param2 = 0;

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

static void qcom_glink_rx_done_work(struct work_struct *work)
{
	struct glink_channel *channel = container_of(work, struct glink_channel,
						     intent_work);
	struct qcom_glink *glink = channel->glink;
	struct glink_core_rx_intent *intent, *tmp;
	struct {
		u16 id;
		u16 lcid;
		u32 liid;
	} __packed cmd;

	unsigned int cid = channel->lcid;
	unsigned int iid;
	bool reuse;
	unsigned long flags;

	spin_lock_irqsave(&channel->intent_lock, flags);
	list_for_each_entry_safe(intent, tmp, &channel->done_intents, node) {
		list_del(&intent->node);
		spin_unlock_irqrestore(&channel->intent_lock, flags);
		iid = intent->id;
		reuse = intent->reuse;

		cmd.id = reuse ? GLINK_CMD_RX_DONE_W_REUSE : GLINK_CMD_RX_DONE;
		cmd.lcid = cid;
		cmd.liid = iid;

		qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);
		if (!reuse) {
			kfree(intent->data);
			kfree(intent);
		}
		spin_lock_irqsave(&channel->intent_lock, flags);
	}
	spin_unlock_irqrestore(&channel->intent_lock, flags);
}

static void qcom_glink_rx_done(struct qcom_glink *glink,
			       struct glink_channel *channel,
			       struct glink_core_rx_intent *intent)
{
	/* We don't send RX_DONE to intentless systems */
	if (glink->intentless) {
		kfree(intent->data);
		kfree(intent);
		return;
	}

	/* Take it off the tree of receive intents */
	if (!intent->reuse) {
		spin_lock(&channel->intent_lock);
		idr_remove(&channel->liids, intent->id);
		spin_unlock(&channel->intent_lock);
	}

	/* Schedule the sending of a rx_done indication */
	spin_lock(&channel->intent_lock);
	list_add_tail(&intent->node, &channel->done_intents);
	spin_unlock(&channel->intent_lock);

	schedule_work(&channel->intent_work);
}

/**
 * qcom_glink_receive_version() - receive version/features from remote system
 *
 * @glink:	pointer to transport interface
 * @version:	remote version
 * @features:	remote features
 *
 * This function is called in response to a remote-initiated version/feature
 * negotiation sequence.
 */
static void qcom_glink_receive_version(struct qcom_glink *glink,
				       u32 version,
				       u32 features)
{
	switch (version) {
	case 0:
		break;
	case GLINK_VERSION_1:
		glink->features &= features;
		fallthrough;
	default:
		qcom_glink_send_version_ack(glink);
		break;
	}
}

/**
 * qcom_glink_receive_version_ack() - receive negotiation ack from remote system
 *
 * @glink:	pointer to transport interface
 * @version:	remote version response
 * @features:	remote features response
 *
 * This function is called in response to a local-initiated version/feature
 * negotiation sequence and is the counter-offer from the remote side based
 * upon the initial version and feature set requested.
 */
static void qcom_glink_receive_version_ack(struct qcom_glink *glink,
					   u32 version,
					   u32 features)
{
	switch (version) {
	case 0:
		/* Version negotiation failed */
		break;
	case GLINK_VERSION_1:
		if (features == glink->features)
			break;

		glink->features &= features;
		fallthrough;
	default:
		qcom_glink_send_version(glink);
		break;
	}
}

/**
 * qcom_glink_send_intent_req_ack() - convert an rx intent request ack cmd to
 * 	wire format and transmit
 * @glink:	The transport to transmit on.
 * @channel:	The glink channel
 * @granted:	The request response to encode.
 *
 * Return: 0 on success or standard Linux error code.
 */
static int qcom_glink_send_intent_req_ack(struct qcom_glink *glink,
					  struct glink_channel *channel,
					  bool granted)
{
	struct glink_msg msg;

	msg.cmd = cpu_to_le16(GLINK_CMD_RX_INTENT_REQ_ACK);
	msg.param1 = cpu_to_le16(channel->lcid);
	msg.param2 = cpu_to_le32(granted);

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

	return 0;
}

/**
 * qcom_glink_advertise_intent - convert an rx intent cmd to wire format and
 *			   transmit
 * @glink:	The transport to transmit on.
 * @channel:	The local channel
 * @intent:	The intent to pass on to remote.
 *
 * Return: 0 on success or standard Linux error code.
 */
static int qcom_glink_advertise_intent(struct qcom_glink *glink,
				       struct glink_channel *channel,
				       struct glink_core_rx_intent *intent)
{
	struct command {
		__le16 id;
		__le16 lcid;
		__le32 count;
		__le32 size;
		__le32 liid;
	} __packed;
	struct command cmd;

	cmd.id = cpu_to_le16(GLINK_CMD_INTENT);
	cmd.lcid = cpu_to_le16(channel->lcid);
	cmd.count = cpu_to_le32(1);
	cmd.size = cpu_to_le32(intent->size);
	cmd.liid = cpu_to_le32(intent->id);

	qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);

	return 0;
}

static struct glink_core_rx_intent *
qcom_glink_alloc_intent(struct qcom_glink *glink,
			struct glink_channel *channel,
			size_t size,
			bool reuseable)
{
	struct glink_core_rx_intent *intent;
	int ret;
	unsigned long flags;

	intent = kzalloc(sizeof(*intent), GFP_KERNEL);
	if (!intent)
		return NULL;

	intent->data = kzalloc(size, GFP_KERNEL);
	if (!intent->data)
		goto free_intent;

	spin_lock_irqsave(&channel->intent_lock, flags);
	ret = idr_alloc_cyclic(&channel->liids, intent, 1, -1, GFP_ATOMIC);
	if (ret < 0) {
		spin_unlock_irqrestore(&channel->intent_lock, flags);
		goto free_data;
	}
	spin_unlock_irqrestore(&channel->intent_lock, flags);

	intent->id = ret;
	intent->size = size;
	intent->reuse = reuseable;

	return intent;

free_data:
	kfree(intent->data);
free_intent:
	kfree(intent);
	return NULL;
}

static void qcom_glink_handle_rx_done(struct qcom_glink *glink,
				      u32 cid, uint32_t iid,
				      bool reuse)
{
	struct glink_core_rx_intent *intent;
	struct glink_channel *channel;
	unsigned long flags;

	spin_lock_irqsave(&glink->idr_lock, flags);
	channel = idr_find(&glink->rcids, cid);
	spin_unlock_irqrestore(&glink->idr_lock, flags);
	if (!channel) {
		dev_err(glink->dev, "invalid channel id received\n");
		return;
	}

	spin_lock_irqsave(&channel->intent_lock, flags);
	intent = idr_find(&channel->riids, iid);

	if (!intent) {
		spin_unlock_irqrestore(&channel->intent_lock, flags);
		dev_err(glink->dev, "invalid intent id received\n");
		return;
	}

	intent->in_use = false;

	if (!reuse) {
		idr_remove(&channel->riids, intent->id);
		kfree(intent);
	}
	spin_unlock_irqrestore(&channel->intent_lock, flags);

	if (reuse) {
		WRITE_ONCE(channel->intent_received, true);
		wake_up_all(&channel->intent_req_wq);
	}
}

/**
 * qcom_glink_handle_intent_req() - Receive a request for rx_intent
 *					    from remote side
 * @glink:      Pointer to the transport interface
 * @cid:	Remote channel ID
 * @size:	size of the intent
 *
 * The function searches for the local channel to which the request for
 * rx_intent has arrived and allocates and notifies the remote back
 */
static void qcom_glink_handle_intent_req(struct qcom_glink *glink,
					 u32 cid, size_t size)
{
	struct glink_core_rx_intent *intent;
	struct glink_channel *channel;
	unsigned long flags;

	spin_lock_irqsave(&glink->idr_lock, flags);
	channel = idr_find(&glink->rcids, cid);
	spin_unlock_irqrestore(&glink->idr_lock, flags);

	if (!channel) {
		pr_err("%s channel not found for cid %d\n", __func__, cid);
		return;
	}

	intent = qcom_glink_alloc_intent(glink, channel, size, false);
	if (intent)
		qcom_glink_advertise_intent(glink, channel, intent);

	qcom_glink_send_intent_req_ack(glink, channel, !!intent);
}

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(struct_size(dcmd, data, extra), GFP_ATOMIC);
	if (!dcmd)
		return -ENOMEM;

	INIT_LIST_HEAD(&dcmd->node);

	qcom_glink_rx_peek(glink, &dcmd->msg, 0, 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_core_rx_intent *intent;
	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;
	unsigned int liid;
	int ret = 0;
	unsigned long flags;

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

	qcom_glink_rx_peek(glink, &hdr, 0, 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;
	}

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

		/* Drop the message */
		goto advance_rx;
	}

	if (glink->intentless) {
		/* Might have an ongoing, fragmented, message to append */
		if (!channel->buf) {
			intent = kzalloc(sizeof(*intent), GFP_ATOMIC);
			if (!intent)
				return -ENOMEM;

			intent->data = kmalloc(chunk_size + left_size,
					       GFP_ATOMIC);
			if (!intent->data) {
				kfree(intent);
				return -ENOMEM;
			}

			intent->id = 0xbabababa;
			intent->size = chunk_size + left_size;
			intent->offset = 0;

			channel->buf = intent;
		} else {
			intent = channel->buf;
		}
	} else {
		liid = le32_to_cpu(hdr.msg.param2);

		spin_lock_irqsave(&channel->intent_lock, flags);
		intent = idr_find(&channel->liids, liid);
		spin_unlock_irqrestore(&channel->intent_lock, flags);

		if (!intent) {
			dev_err(glink->dev,
				"no intent found for channel %s intent %d",
				channel->name, liid);
			ret = -ENOENT;
			goto advance_rx;
		}
	}

	if (intent->size - intent->offset < chunk_size) {
		dev_err(glink->dev, "Insufficient space in intent\n");

		/* The packet header lied, drop payload */
		goto advance_rx;
	}

	qcom_glink_rx_peek(glink, intent->data + intent->offset,
			   sizeof(hdr), chunk_size);
	intent->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,
					intent->data,
					intent->offset,
					channel->ept.priv,
					RPMSG_ADDR_ANY);
		}
		spin_unlock(&channel->recv_lock);

		intent->offset = 0;
		channel->buf = NULL;

		qcom_glink_rx_done(glink, channel, intent);
	}

advance_rx:
	qcom_glink_rx_advance(glink, ALIGN(sizeof(hdr) + chunk_size, 8));

	return ret;
}

static void qcom_glink_handle_intent(struct qcom_glink *glink,
				     unsigned int cid,
				     unsigned int count,
				     size_t avail)
{
	struct glink_core_rx_intent *intent;
	struct glink_channel *channel;
	struct intent_pair {
		__le32 size;
		__le32 iid;
	};

	struct {
		struct glink_msg msg;
		struct intent_pair intents[];
	} __packed * msg;

	const size_t msglen = struct_size(msg, intents, count);
	int ret;
	int i;
	unsigned long flags;

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

	spin_lock_irqsave(&glink->idr_lock, flags);
	channel = idr_find(&glink->rcids, cid);
	spin_unlock_irqrestore(&glink->idr_lock, flags);
	if (!channel) {
		dev_err(glink->dev, "intents for non-existing channel\n");
		qcom_glink_rx_advance(glink, ALIGN(msglen, 8));
		return;
	}

	msg = kmalloc(msglen, GFP_ATOMIC);
	if (!msg)
		return;

	qcom_glink_rx_peek(glink, msg, 0, msglen);

	for (i = 0; i < count; ++i) {
		intent = kzalloc(sizeof(*intent), GFP_ATOMIC);
		if (!intent)
			break;

		intent->id = le32_to_cpu(msg->intents[i].iid);
		intent->size = le32_to_cpu(msg->intents[i].size);

		spin_lock_irqsave(&channel->intent_lock, flags);
		ret = idr_alloc(&channel->riids, intent,
				intent->id, intent->id + 1, GFP_ATOMIC);
		spin_unlock_irqrestore(&channel->intent_lock, flags);

		if (ret < 0)
			dev_err(glink->dev, "failed to store remote intent\n");
	}

	WRITE_ONCE(channel->intent_received, true);
	wake_up_all(&channel->intent_req_wq);

	kfree(msg);
	qcom_glink_rx_advance(glink, ALIGN(msglen, 8));
}

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

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

	complete_all(&channel->open_ack);

	return 0;
}

/**
 * qcom_glink_set_flow_control() - convert a signal cmd to wire format and transmit
 * @ept:	Rpmsg endpoint for channel.
 * @pause:	Pause transmission
 * @dst:	destination address of the endpoint
 *
 * Return: 0 on success or standard Linux error code.
 */
static int qcom_glink_set_flow_control(struct rpmsg_endpoint *ept, bool pause, u32 dst)
{
	struct glink_channel *channel = to_glink_channel(ept);
	struct qcom_glink *glink = channel->glink;
	struct glink_msg msg;
	u32 sigs = 0;

	if (pause)
		sigs |= NATIVE_DTR_SIG | NATIVE_RTS_SIG;

	msg.cmd = cpu_to_le16(GLINK_CMD_SIGNALS);
	msg.param1 = cpu_to_le16(channel->lcid);
	msg.param2 = cpu_to_le32(sigs);

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

static void qcom_glink_handle_signals(struct qcom_glink *glink,
				      unsigned int rcid, unsigned int sigs)
{
	struct glink_channel *channel;
	unsigned long flags;
	bool enable;

	spin_lock_irqsave(&glink->idr_lock, flags);
	channel = idr_find(&glink->rcids, rcid);
	spin_unlock_irqrestore(&glink->idr_lock, flags);
	if (!channel) {
		dev_err(glink->dev, "signal for non-existing channel\n");
		return;
	}

	enable = sigs & NATIVE_DSR_SIG || sigs & NATIVE_CTS_SIG;

	if (channel->ept.flow_cb)
		channel->ept.flow_cb(channel->ept.rpdev, channel->ept.priv, enable);
}

void qcom_glink_native_rx(struct qcom_glink *glink)
{
	struct glink_msg msg;
	unsigned int param1;
	unsigned int param2;
	unsigned int avail;
	unsigned int cmd;
	int ret = 0;

	/* To wakeup any blocking writers */
	wake_up_all(&glink->tx_avail_notify);

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

		qcom_glink_rx_peek(glink, &msg, 0, sizeof(msg));

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

		switch (cmd) {
		case GLINK_CMD_VERSION:
		case GLINK_CMD_VERSION_ACK:
		case GLINK_CMD_CLOSE:
		case GLINK_CMD_CLOSE_ACK:
		case GLINK_CMD_RX_INTENT_REQ:
			ret = qcom_glink_rx_defer(glink, 0);
			break;
		case GLINK_CMD_OPEN_ACK:
			ret = qcom_glink_rx_open_ack(glink, param1);
			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
			break;
		case GLINK_CMD_OPEN:
			ret = qcom_glink_rx_defer(glink, param2);
			break;
		case GLINK_CMD_TX_DATA:
		case GLINK_CMD_TX_DATA_CONT:
			ret = qcom_glink_rx_data(glink, avail);
			break;
		case GLINK_CMD_READ_NOTIF:
			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
			qcom_glink_tx_kick(glink);
			break;
		case GLINK_CMD_INTENT:
			qcom_glink_handle_intent(glink, param1, param2, avail);
			break;
		case GLINK_CMD_RX_DONE:
			qcom_glink_handle_rx_done(glink, param1, param2, false);
			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
			break;
		case GLINK_CMD_RX_DONE_W_REUSE:
			qcom_glink_handle_rx_done(glink, param1, param2, true);
			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
			break;
		case GLINK_CMD_RX_INTENT_REQ_ACK:
			qcom_glink_handle_intent_req_ack(glink, param1, param2);
			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
			break;
		case GLINK_CMD_SIGNALS:
			qcom_glink_handle_signals(glink, param1, param2);
			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
			break;
		default:
			dev_err(glink->dev, "unhandled rx cmd: %d\n", cmd);
			ret = -EINVAL;
			break;
		}

		if (ret)
			break;
	}
}
EXPORT_SYMBOL(qcom_glink_native_rx);

/* 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;
	unsigned long flags;

	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*/
	spin_lock_irqsave(&glink->idr_lock, flags);
	idr_remove(&glink->lcids, channel->lcid);
	spin_unlock_irqrestore(&glink->idr_lock, flags);

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 qcom_glink_send_open_req() reference and the last reference
	 * will be relesed after receiving remote_close or transport unregister
	 * by calling qcom_glink_native_remove().
	 */
	qcom_glink_send_close_req(glink, channel);

	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;
	unsigned long flags;

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

	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 int qcom_glink_announce_create(struct rpmsg_device *rpdev)
{
	struct glink_channel *channel = to_glink_channel(rpdev->ept);
	struct device_node *np = rpdev->dev.of_node;
	struct qcom_glink *glink = channel->glink;
	struct glink_core_rx_intent *intent;
	const struct property *prop = NULL;
	__be32 defaults[] = { cpu_to_be32(SZ_1K), cpu_to_be32(5) };
	int num_intents;
	int num_groups = 1;
	__be32 *val = defaults;
	int size;

	if (glink->intentless || !completion_done(&channel->open_ack))
		return 0;

	prop = of_find_property(np, "qcom,intents", NULL);
	if (prop) {
		val = prop->value;
		num_groups = prop->length / sizeof(u32) / 2;
	}

	/* Channel is now open, advertise base set of intents */
	while (num_groups--) {
		size = be32_to_cpup(val++);
		num_intents = be32_to_cpup(val++);
		while (num_intents--) {
			intent = qcom_glink_alloc_intent(glink, channel, size,
							 true);
			if (!intent)
				break;

			qcom_glink_advertise_intent(glink, channel, intent);
		}
	}
	return 0;
}

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_request_intent(struct qcom_glink *glink,
				     struct glink_channel *channel,
				     size_t size)
{
	struct {
		u16 id;
		u16 cid;
		u32 size;
	} __packed cmd;

	int ret;

	mutex_lock(&channel->intent_req_lock);

	WRITE_ONCE(channel->intent_req_result, -1);
	WRITE_ONCE(channel->intent_received, false);

	cmd.id = GLINK_CMD_RX_INTENT_REQ;
	cmd.cid = channel->lcid;
	cmd.size = size;

	ret = qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);
	if (ret)
		goto unlock;

	ret = wait_event_timeout(channel->intent_req_wq,
				 READ_ONCE(channel->intent_req_result) >= 0 &&
				 READ_ONCE(channel->intent_received),
				 10 * HZ);
	if (!ret) {
		dev_err(glink->dev, "intent request timed out\n");
		ret = -ETIMEDOUT;
	} else {
		ret = READ_ONCE(channel->intent_req_result) ? 0 : -ECANCELED;
	}

unlock:
	mutex_unlock(&channel->intent_req_lock);
	return ret;
}

static int __qcom_glink_send(struct glink_channel *channel,
			     void *data, int len, bool wait)
{
	struct qcom_glink *glink = channel->glink;
	struct glink_core_rx_intent *intent = NULL;
	struct glink_core_rx_intent *tmp;
	int iid = 0;
	struct {
		struct glink_msg msg;
		__le32 chunk_size;
		__le32 left_size;
	} __packed req;
	int ret;
	unsigned long flags;
	int chunk_size = len;
	size_t offset = 0;

	if (!glink->intentless) {
		while (!intent) {
			spin_lock_irqsave(&channel->intent_lock, flags);
			idr_for_each_entry(&channel->riids, tmp, iid) {
				if (tmp->size >= len && !tmp->in_use) {
					if (!intent)
						intent = tmp;
					else if (intent->size > tmp->size)
						intent = tmp;
					if (intent->size == len)
						break;
				}
			}
			if (intent)
				intent->in_use = true;
			spin_unlock_irqrestore(&channel->intent_lock, flags);

			/* We found an available intent */
			if (intent)
				break;

			if (!wait)
				return -EBUSY;

			ret = qcom_glink_request_intent(glink, channel, len);
			if (ret < 0)
				return ret;
		}

		iid = intent->id;
	}

	while (offset < len) {
		chunk_size = len - offset;
		if (chunk_size > SZ_8K && wait)
			chunk_size = SZ_8K;

		req.msg.cmd = cpu_to_le16(offset == 0 ? GLINK_CMD_TX_DATA : GLINK_CMD_TX_DATA_CONT);
		req.msg.param1 = cpu_to_le16(channel->lcid);
		req.msg.param2 = cpu_to_le32(iid);
		req.chunk_size = cpu_to_le32(chunk_size);
		req.left_size = cpu_to_le32(len - offset - chunk_size);

		ret = qcom_glink_tx(glink, &req, sizeof(req), data + offset, chunk_size, wait);
		if (ret) {
			/* Mark intent available if we failed */
			if (intent)
				intent->in_use = false;
			return ret;
		}

		offset += chunk_size;
	}

	return 0;
}

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);
}

static int qcom_glink_sendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
{
	struct glink_channel *channel = to_glink_channel(ept);

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

static int qcom_glink_trysendto(struct rpmsg_endpoint *ept, void *data, int len, u32 dst)
{
	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,
	.announce_create = qcom_glink_announce_create,
};

static const struct rpmsg_endpoint_ops glink_endpoint_ops = {
	.destroy_ept = qcom_glink_destroy_ept,
	.send = qcom_glink_send,
	.sendto = qcom_glink_sendto,
	.trysend = qcom_glink_trysend,
	.trysendto = qcom_glink_trysendto,
	.set_flow_control = qcom_glink_set_flow_control,
};

static void qcom_glink_rpdev_release(struct device *dev)
{
	struct rpmsg_device *rpdev = to_rpmsg_device(dev);

	kfree(rpdev->driver_override);
	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;
	unsigned long flags;

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

	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;
	}

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

	complete_all(&channel->open_req);

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

		rpdev->ept = &channel->ept;
		strscpy_pad(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 rcid_remove;

		channel->rpdev = rpdev;
	}

	return 0;

rcid_remove:
	spin_lock_irqsave(&glink->idr_lock, flags);
	idr_remove(&glink->rcids, channel->rcid);
	channel->rcid = 0;
	spin_unlock_irqrestore(&glink->idr_lock, flags);
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;
	unsigned long flags;

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

	/* cancel pending rx_done work */
	cancel_work_sync(&channel->intent_work);

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

		rpmsg_unregister_device(glink->dev, &chinfo);
	}
	channel->rpdev = NULL;

	qcom_glink_send_close_ack(glink, channel->rcid);

	spin_lock_irqsave(&glink->idr_lock, flags);
	idr_remove(&glink->rcids, channel->rcid);
	channel->rcid = 0;
	spin_unlock_irqrestore(&glink->idr_lock, flags);

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

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

	/* To wakeup any blocking writers */
	wake_up_all(&glink->tx_avail_notify);

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

	idr_remove(&glink->lcids, channel->lcid);
	channel->lcid = 0;
	spin_unlock_irqrestore(&glink->idr_lock, flags);

	/* Decouple the potential rpdev from the channel */
	if (channel->rpdev) {
		strscpy(chinfo.name, channel->name, sizeof(chinfo.name));
		chinfo.src = RPMSG_ADDR_ANY;
		chinfo.dst = RPMSG_ADDR_ANY;

		rpmsg_unregister_device(glink->dev, &chinfo);
	}
	channel->rpdev = NULL;

	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 GLINK_CMD_VERSION:
			qcom_glink_receive_version(glink, param1, param2);
			break;
		case GLINK_CMD_VERSION_ACK:
			qcom_glink_receive_version_ack(glink, param1, param2);
			break;
		case GLINK_CMD_OPEN:
			qcom_glink_rx_open(glink, param1, msg->data);
			break;
		case GLINK_CMD_CLOSE:
			qcom_glink_rx_close(glink, param1);
			break;
		case GLINK_CMD_CLOSE_ACK:
			qcom_glink_rx_close_ack(glink, param1);
			break;
		case GLINK_CMD_RX_INTENT_REQ:
			qcom_glink_handle_intent_req(glink, param1, param2);
			break;
		default:
			WARN(1, "Unknown defer object %d\n", cmd);
			break;
		}

		kfree(dcmd);
	}
}

static void qcom_glink_cancel_rx_work(struct qcom_glink *glink)
{
	struct glink_defer_cmd *dcmd;
	struct glink_defer_cmd *tmp;

	/* cancel any pending deferred rx_work */
	cancel_work_sync(&glink->rx_work);

	list_for_each_entry_safe(dcmd, tmp, &glink->rx_queue, node)
		kfree(dcmd);
}

static ssize_t rpmsg_name_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	int ret = 0;
	const char *name;

	ret = of_property_read_string(dev->of_node, "label", &name);
	if (ret < 0)
		name = dev->of_node->name;

	return sysfs_emit(buf, "%s\n", name);
}
static DEVICE_ATTR_RO(rpmsg_name);

static struct attribute *qcom_glink_attrs[] = {
	&dev_attr_rpmsg_name.attr,
	NULL
};
ATTRIBUTE_GROUPS(qcom_glink);

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

	/* Release qcom_glink_alloc_channel() reference */
	kref_put(&channel->refcount, qcom_glink_channel_release);
	kfree(rpdev->driver_override);
	kfree(rpdev);
}

static int qcom_glink_create_chrdev(struct qcom_glink *glink)
{
	struct rpmsg_device *rpdev;
	struct glink_channel *channel;

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

	channel = qcom_glink_alloc_channel(glink, "rpmsg_chrdev");
	if (IS_ERR(channel)) {
		kfree(rpdev);
		return PTR_ERR(channel);
	}
	channel->rpdev = rpdev;

	rpdev->ept = &channel->ept;
	rpdev->ops = &glink_device_ops;
	rpdev->dev.parent = glink->dev;
	rpdev->dev.release = qcom_glink_device_release;

	return rpmsg_ctrldev_register_device(rpdev);
}

struct qcom_glink *qcom_glink_native_probe(struct device *dev,
					   unsigned long features,
					   struct qcom_glink_pipe *rx,
					   struct qcom_glink_pipe *tx,
					   bool intentless)
{
	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;

	glink->features = features;
	glink->intentless = intentless;

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

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

	glink->dev->groups = qcom_glink_groups;

	ret = device_add_groups(dev, qcom_glink_groups);
	if (ret)
		dev_err(dev, "failed to add groups\n");

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

	ret = qcom_glink_create_chrdev(glink);
	if (ret)
		dev_err(glink->dev, "failed to register chrdev\n");

	return glink;
}
EXPORT_SYMBOL_GPL(qcom_glink_native_probe);

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;
	unsigned long flags;
	int cid;
	int ret;

	qcom_glink_cancel_rx_work(glink);

	/* Fail all attempts at sending messages */
	spin_lock_irqsave(&glink->tx_lock, flags);
	glink->abort_tx = true;
	wake_up_all(&glink->tx_avail_notify);
	spin_unlock_irqrestore(&glink->tx_lock, flags);

	/* Abort any senders waiting for intent requests */
	spin_lock_irqsave(&glink->idr_lock, flags);
	idr_for_each_entry(&glink->lcids, channel, cid)
		qcom_glink_intent_req_abort(channel);
	spin_unlock_irqrestore(&glink->idr_lock, flags);

	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);

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

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

MODULE_DESCRIPTION("Qualcomm GLINK driver");
MODULE_LICENSE("GPL v2");