summaryrefslogtreecommitdiff
path: root/drivers/mailbox/bcm-flexrm-mailbox.c
blob: da67882caa7bf7f39efa6d6df03dadd29122b6cf (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
/* Broadcom FlexRM Mailbox Driver
 *
 * Copyright (C) 2017 Broadcom
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Each Broadcom FlexSparx4 offload engine is implemented as an
 * extension to Broadcom FlexRM ring manager. The FlexRM ring
 * manager provides a set of rings which can be used to submit
 * work to a FlexSparx4 offload engine.
 *
 * This driver creates a mailbox controller using a set of FlexRM
 * rings where each mailbox channel represents a separate FlexRM ring.
 */

#include <asm/barrier.h>
#include <asm/byteorder.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/err.h>
#include <linux/idr.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mailbox_controller.h>
#include <linux/mailbox_client.h>
#include <linux/mailbox/brcm-message.h>
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>

/* ====== FlexRM register defines ===== */

/* FlexRM configuration */
#define RING_REGS_SIZE					0x10000
#define RING_DESC_SIZE					8
#define RING_DESC_INDEX(offset)				\
			((offset) / RING_DESC_SIZE)
#define RING_DESC_OFFSET(index)				\
			((index) * RING_DESC_SIZE)
#define RING_MAX_REQ_COUNT				1024
#define RING_BD_ALIGN_ORDER				12
#define RING_BD_ALIGN_CHECK(addr)			\
			(!((addr) & ((0x1 << RING_BD_ALIGN_ORDER) - 1)))
#define RING_BD_TOGGLE_INVALID(offset)			\
			(((offset) >> RING_BD_ALIGN_ORDER) & 0x1)
#define RING_BD_TOGGLE_VALID(offset)			\
			(!RING_BD_TOGGLE_INVALID(offset))
#define RING_BD_DESC_PER_REQ				32
#define RING_BD_DESC_COUNT				\
			(RING_MAX_REQ_COUNT * RING_BD_DESC_PER_REQ)
#define RING_BD_SIZE					\
			(RING_BD_DESC_COUNT * RING_DESC_SIZE)
#define RING_CMPL_ALIGN_ORDER				13
#define RING_CMPL_DESC_COUNT				RING_MAX_REQ_COUNT
#define RING_CMPL_SIZE					\
			(RING_CMPL_DESC_COUNT * RING_DESC_SIZE)
#define RING_VER_MAGIC					0x76303031

/* Per-Ring register offsets */
#define RING_VER					0x000
#define RING_BD_START_ADDR				0x004
#define RING_BD_READ_PTR				0x008
#define RING_BD_WRITE_PTR				0x00c
#define RING_BD_READ_PTR_DDR_LS				0x010
#define RING_BD_READ_PTR_DDR_MS				0x014
#define RING_CMPL_START_ADDR				0x018
#define RING_CMPL_WRITE_PTR				0x01c
#define RING_NUM_REQ_RECV_LS				0x020
#define RING_NUM_REQ_RECV_MS				0x024
#define RING_NUM_REQ_TRANS_LS				0x028
#define RING_NUM_REQ_TRANS_MS				0x02c
#define RING_NUM_REQ_OUTSTAND				0x030
#define RING_CONTROL					0x034
#define RING_FLUSH_DONE					0x038
#define RING_MSI_ADDR_LS				0x03c
#define RING_MSI_ADDR_MS				0x040
#define RING_MSI_CONTROL				0x048
#define RING_BD_READ_PTR_DDR_CONTROL			0x04c
#define RING_MSI_DATA_VALUE				0x064

/* Register RING_BD_START_ADDR fields */
#define BD_LAST_UPDATE_HW_SHIFT				28
#define BD_LAST_UPDATE_HW_MASK				0x1
#define BD_START_ADDR_VALUE(pa)				\
	((u32)((((dma_addr_t)(pa)) >> RING_BD_ALIGN_ORDER) & 0x0fffffff))
#define BD_START_ADDR_DECODE(val)			\
	((dma_addr_t)((val) & 0x0fffffff) << RING_BD_ALIGN_ORDER)

/* Register RING_CMPL_START_ADDR fields */
#define CMPL_START_ADDR_VALUE(pa)			\
	((u32)((((u64)(pa)) >> RING_CMPL_ALIGN_ORDER) & 0x03ffffff))

/* Register RING_CONTROL fields */
#define CONTROL_MASK_DISABLE_CONTROL			12
#define CONTROL_FLUSH_SHIFT				5
#define CONTROL_ACTIVE_SHIFT				4
#define CONTROL_RATE_ADAPT_MASK				0xf
#define CONTROL_RATE_DYNAMIC				0x0
#define CONTROL_RATE_FAST				0x8
#define CONTROL_RATE_MEDIUM				0x9
#define CONTROL_RATE_SLOW				0xa
#define CONTROL_RATE_IDLE				0xb

/* Register RING_FLUSH_DONE fields */
#define FLUSH_DONE_MASK					0x1

/* Register RING_MSI_CONTROL fields */
#define MSI_TIMER_VAL_SHIFT				16
#define MSI_TIMER_VAL_MASK				0xffff
#define MSI_ENABLE_SHIFT				15
#define MSI_ENABLE_MASK					0x1
#define MSI_COUNT_SHIFT					0
#define MSI_COUNT_MASK					0x3ff

/* Register RING_BD_READ_PTR_DDR_CONTROL fields */
#define BD_READ_PTR_DDR_TIMER_VAL_SHIFT			16
#define BD_READ_PTR_DDR_TIMER_VAL_MASK			0xffff
#define BD_READ_PTR_DDR_ENABLE_SHIFT			15
#define BD_READ_PTR_DDR_ENABLE_MASK			0x1

/* ====== FlexRM ring descriptor defines ===== */

/* Completion descriptor format */
#define CMPL_OPAQUE_SHIFT			0
#define CMPL_OPAQUE_MASK			0xffff
#define CMPL_ENGINE_STATUS_SHIFT		16
#define CMPL_ENGINE_STATUS_MASK			0xffff
#define CMPL_DME_STATUS_SHIFT			32
#define CMPL_DME_STATUS_MASK			0xffff
#define CMPL_RM_STATUS_SHIFT			48
#define CMPL_RM_STATUS_MASK			0xffff

/* Completion DME status code */
#define DME_STATUS_MEM_COR_ERR			BIT(0)
#define DME_STATUS_MEM_UCOR_ERR			BIT(1)
#define DME_STATUS_FIFO_UNDERFLOW		BIT(2)
#define DME_STATUS_FIFO_OVERFLOW		BIT(3)
#define DME_STATUS_RRESP_ERR			BIT(4)
#define DME_STATUS_BRESP_ERR			BIT(5)
#define DME_STATUS_ERROR_MASK			(DME_STATUS_MEM_COR_ERR | \
						 DME_STATUS_MEM_UCOR_ERR | \
						 DME_STATUS_FIFO_UNDERFLOW | \
						 DME_STATUS_FIFO_OVERFLOW | \
						 DME_STATUS_RRESP_ERR | \
						 DME_STATUS_BRESP_ERR)

/* Completion RM status code */
#define RM_STATUS_CODE_SHIFT			0
#define RM_STATUS_CODE_MASK			0x3ff
#define RM_STATUS_CODE_GOOD			0x0
#define RM_STATUS_CODE_AE_TIMEOUT		0x3ff

/* General descriptor format */
#define DESC_TYPE_SHIFT				60
#define DESC_TYPE_MASK				0xf
#define DESC_PAYLOAD_SHIFT			0
#define DESC_PAYLOAD_MASK			0x0fffffffffffffff

/* Null descriptor format  */
#define NULL_TYPE				0
#define NULL_TOGGLE_SHIFT			58
#define NULL_TOGGLE_MASK			0x1

/* Header descriptor format */
#define HEADER_TYPE				1
#define HEADER_TOGGLE_SHIFT			58
#define HEADER_TOGGLE_MASK			0x1
#define HEADER_ENDPKT_SHIFT			57
#define HEADER_ENDPKT_MASK			0x1
#define HEADER_STARTPKT_SHIFT			56
#define HEADER_STARTPKT_MASK			0x1
#define HEADER_BDCOUNT_SHIFT			36
#define HEADER_BDCOUNT_MASK			0x1f
#define HEADER_BDCOUNT_MAX			HEADER_BDCOUNT_MASK
#define HEADER_FLAGS_SHIFT			16
#define HEADER_FLAGS_MASK			0xffff
#define HEADER_OPAQUE_SHIFT			0
#define HEADER_OPAQUE_MASK			0xffff

/* Source (SRC) descriptor format */
#define SRC_TYPE				2
#define SRC_LENGTH_SHIFT			44
#define SRC_LENGTH_MASK				0xffff
#define SRC_ADDR_SHIFT				0
#define SRC_ADDR_MASK				0x00000fffffffffff

/* Destination (DST) descriptor format */
#define DST_TYPE				3
#define DST_LENGTH_SHIFT			44
#define DST_LENGTH_MASK				0xffff
#define DST_ADDR_SHIFT				0
#define DST_ADDR_MASK				0x00000fffffffffff

/* Immediate (IMM) descriptor format */
#define IMM_TYPE				4
#define IMM_DATA_SHIFT				0
#define IMM_DATA_MASK				0x0fffffffffffffff

/* Next pointer (NPTR) descriptor format */
#define NPTR_TYPE				5
#define NPTR_TOGGLE_SHIFT			58
#define NPTR_TOGGLE_MASK			0x1
#define NPTR_ADDR_SHIFT				0
#define NPTR_ADDR_MASK				0x00000fffffffffff

/* Mega source (MSRC) descriptor format */
#define MSRC_TYPE				6
#define MSRC_LENGTH_SHIFT			44
#define MSRC_LENGTH_MASK			0xffff
#define MSRC_ADDR_SHIFT				0
#define MSRC_ADDR_MASK				0x00000fffffffffff

/* Mega destination (MDST) descriptor format */
#define MDST_TYPE				7
#define MDST_LENGTH_SHIFT			44
#define MDST_LENGTH_MASK			0xffff
#define MDST_ADDR_SHIFT				0
#define MDST_ADDR_MASK				0x00000fffffffffff

/* Source with tlast (SRCT) descriptor format */
#define SRCT_TYPE				8
#define SRCT_LENGTH_SHIFT			44
#define SRCT_LENGTH_MASK			0xffff
#define SRCT_ADDR_SHIFT				0
#define SRCT_ADDR_MASK				0x00000fffffffffff

/* Destination with tlast (DSTT) descriptor format */
#define DSTT_TYPE				9
#define DSTT_LENGTH_SHIFT			44
#define DSTT_LENGTH_MASK			0xffff
#define DSTT_ADDR_SHIFT				0
#define DSTT_ADDR_MASK				0x00000fffffffffff

/* Immediate with tlast (IMMT) descriptor format */
#define IMMT_TYPE				10
#define IMMT_DATA_SHIFT				0
#define IMMT_DATA_MASK				0x0fffffffffffffff

/* Descriptor helper macros */
#define DESC_DEC(_d, _s, _m)			(((_d) >> (_s)) & (_m))
#define DESC_ENC(_d, _v, _s, _m)		\
			do { \
				(_d) &= ~((u64)(_m) << (_s)); \
				(_d) |= (((u64)(_v) & (_m)) << (_s)); \
			} while (0)

/* ====== FlexRM data structures ===== */

struct flexrm_ring {
	/* Unprotected members */
	int num;
	struct flexrm_mbox *mbox;
	void __iomem *regs;
	bool irq_requested;
	unsigned int irq;
	unsigned int msi_timer_val;
	unsigned int msi_count_threshold;
	struct ida requests_ida;
	struct brcm_message *requests[RING_MAX_REQ_COUNT];
	void *bd_base;
	dma_addr_t bd_dma_base;
	u32 bd_write_offset;
	void *cmpl_base;
	dma_addr_t cmpl_dma_base;
	/* Protected members */
	spinlock_t lock;
	struct brcm_message *last_pending_msg;
	u32 cmpl_read_offset;
};

struct flexrm_mbox {
	struct device *dev;
	void __iomem *regs;
	u32 num_rings;
	struct flexrm_ring *rings;
	struct dma_pool *bd_pool;
	struct dma_pool *cmpl_pool;
	struct mbox_controller controller;
};

/* ====== FlexRM ring descriptor helper routines ===== */

static u64 flexrm_read_desc(void *desc_ptr)
{
	return le64_to_cpu(*((u64 *)desc_ptr));
}

static void flexrm_write_desc(void *desc_ptr, u64 desc)
{
	*((u64 *)desc_ptr) = cpu_to_le64(desc);
}

static u32 flexrm_cmpl_desc_to_reqid(u64 cmpl_desc)
{
	return (u32)(cmpl_desc & CMPL_OPAQUE_MASK);
}

static int flexrm_cmpl_desc_to_error(u64 cmpl_desc)
{
	u32 status;

	status = DESC_DEC(cmpl_desc, CMPL_DME_STATUS_SHIFT,
			  CMPL_DME_STATUS_MASK);
	if (status & DME_STATUS_ERROR_MASK)
		return -EIO;

	status = DESC_DEC(cmpl_desc, CMPL_RM_STATUS_SHIFT,
			  CMPL_RM_STATUS_MASK);
	status &= RM_STATUS_CODE_MASK;
	if (status == RM_STATUS_CODE_AE_TIMEOUT)
		return -ETIMEDOUT;

	return 0;
}

static bool flexrm_is_next_table_desc(void *desc_ptr)
{
	u64 desc = flexrm_read_desc(desc_ptr);
	u32 type = DESC_DEC(desc, DESC_TYPE_SHIFT, DESC_TYPE_MASK);

	return (type == NPTR_TYPE) ? true : false;
}

static u64 flexrm_next_table_desc(u32 toggle, dma_addr_t next_addr)
{
	u64 desc = 0;

	DESC_ENC(desc, NPTR_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, toggle, NPTR_TOGGLE_SHIFT, NPTR_TOGGLE_MASK);
	DESC_ENC(desc, next_addr, NPTR_ADDR_SHIFT, NPTR_ADDR_MASK);

	return desc;
}

static u64 flexrm_null_desc(u32 toggle)
{
	u64 desc = 0;

	DESC_ENC(desc, NULL_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, toggle, NULL_TOGGLE_SHIFT, NULL_TOGGLE_MASK);

	return desc;
}

static u32 flexrm_estimate_header_desc_count(u32 nhcnt)
{
	u32 hcnt = nhcnt / HEADER_BDCOUNT_MAX;

	if (!(nhcnt % HEADER_BDCOUNT_MAX))
		hcnt += 1;

	return hcnt;
}

static void flexrm_flip_header_toogle(void *desc_ptr)
{
	u64 desc = flexrm_read_desc(desc_ptr);

	if (desc & ((u64)0x1 << HEADER_TOGGLE_SHIFT))
		desc &= ~((u64)0x1 << HEADER_TOGGLE_SHIFT);
	else
		desc |= ((u64)0x1 << HEADER_TOGGLE_SHIFT);

	flexrm_write_desc(desc_ptr, desc);
}

static u64 flexrm_header_desc(u32 toggle, u32 startpkt, u32 endpkt,
			       u32 bdcount, u32 flags, u32 opaque)
{
	u64 desc = 0;

	DESC_ENC(desc, HEADER_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, toggle, HEADER_TOGGLE_SHIFT, HEADER_TOGGLE_MASK);
	DESC_ENC(desc, startpkt, HEADER_STARTPKT_SHIFT, HEADER_STARTPKT_MASK);
	DESC_ENC(desc, endpkt, HEADER_ENDPKT_SHIFT, HEADER_ENDPKT_MASK);
	DESC_ENC(desc, bdcount, HEADER_BDCOUNT_SHIFT, HEADER_BDCOUNT_MASK);
	DESC_ENC(desc, flags, HEADER_FLAGS_SHIFT, HEADER_FLAGS_MASK);
	DESC_ENC(desc, opaque, HEADER_OPAQUE_SHIFT, HEADER_OPAQUE_MASK);

	return desc;
}

static void flexrm_enqueue_desc(u32 nhpos, u32 nhcnt, u32 reqid,
				 u64 desc, void **desc_ptr, u32 *toggle,
				 void *start_desc, void *end_desc)
{
	u64 d;
	u32 nhavail, _toggle, _startpkt, _endpkt, _bdcount;

	/* Sanity check */
	if (nhcnt <= nhpos)
		return;

	/*
	 * Each request or packet start with a HEADER descriptor followed
	 * by one or more non-HEADER descriptors (SRC, SRCT, MSRC, DST,
	 * DSTT, MDST, IMM, and IMMT). The number of non-HEADER descriptors
	 * following a HEADER descriptor is represented by BDCOUNT field
	 * of HEADER descriptor. The max value of BDCOUNT field is 31 which
	 * means we can only have 31 non-HEADER descriptors following one
	 * HEADER descriptor.
	 *
	 * In general use, number of non-HEADER descriptors can easily go
	 * beyond 31. To tackle this situation, we have packet (or request)
	 * extenstion bits (STARTPKT and ENDPKT) in the HEADER descriptor.
	 *
	 * To use packet extension, the first HEADER descriptor of request
	 * (or packet) will have STARTPKT=1 and ENDPKT=0. The intermediate
	 * HEADER descriptors will have STARTPKT=0 and ENDPKT=0. The last
	 * HEADER descriptor will have STARTPKT=0 and ENDPKT=1. Also, the
	 * TOGGLE bit of the first HEADER will be set to invalid state to
	 * ensure that FlexRM does not start fetching descriptors till all
	 * descriptors are enqueued. The user of this function will flip
	 * the TOGGLE bit of first HEADER after all descriptors are
	 * enqueued.
	 */

	if ((nhpos % HEADER_BDCOUNT_MAX == 0) && (nhcnt - nhpos)) {
		/* Prepare the header descriptor */
		nhavail = (nhcnt - nhpos);
		_toggle = (nhpos == 0) ? !(*toggle) : (*toggle);
		_startpkt = (nhpos == 0) ? 0x1 : 0x0;
		_endpkt = (nhavail <= HEADER_BDCOUNT_MAX) ? 0x1 : 0x0;
		_bdcount = (nhavail <= HEADER_BDCOUNT_MAX) ?
				nhavail : HEADER_BDCOUNT_MAX;
		if (nhavail <= HEADER_BDCOUNT_MAX)
			_bdcount = nhavail;
		else
			_bdcount = HEADER_BDCOUNT_MAX;
		d = flexrm_header_desc(_toggle, _startpkt, _endpkt,
					_bdcount, 0x0, reqid);

		/* Write header descriptor */
		flexrm_write_desc(*desc_ptr, d);

		/* Point to next descriptor */
		*desc_ptr += sizeof(desc);
		if (*desc_ptr == end_desc)
			*desc_ptr = start_desc;

		/* Skip next pointer descriptors */
		while (flexrm_is_next_table_desc(*desc_ptr)) {
			*toggle = (*toggle) ? 0 : 1;
			*desc_ptr += sizeof(desc);
			if (*desc_ptr == end_desc)
				*desc_ptr = start_desc;
		}
	}

	/* Write desired descriptor */
	flexrm_write_desc(*desc_ptr, desc);

	/* Point to next descriptor */
	*desc_ptr += sizeof(desc);
	if (*desc_ptr == end_desc)
		*desc_ptr = start_desc;

	/* Skip next pointer descriptors */
	while (flexrm_is_next_table_desc(*desc_ptr)) {
		*toggle = (*toggle) ? 0 : 1;
		*desc_ptr += sizeof(desc);
		if (*desc_ptr == end_desc)
			*desc_ptr = start_desc;
	}
}

static u64 flexrm_src_desc(dma_addr_t addr, unsigned int length)
{
	u64 desc = 0;

	DESC_ENC(desc, SRC_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, length, SRC_LENGTH_SHIFT, SRC_LENGTH_MASK);
	DESC_ENC(desc, addr, SRC_ADDR_SHIFT, SRC_ADDR_MASK);

	return desc;
}

static u64 flexrm_msrc_desc(dma_addr_t addr, unsigned int length_div_16)
{
	u64 desc = 0;

	DESC_ENC(desc, MSRC_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, length_div_16, MSRC_LENGTH_SHIFT, MSRC_LENGTH_MASK);
	DESC_ENC(desc, addr, MSRC_ADDR_SHIFT, MSRC_ADDR_MASK);

	return desc;
}

static u64 flexrm_dst_desc(dma_addr_t addr, unsigned int length)
{
	u64 desc = 0;

	DESC_ENC(desc, DST_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, length, DST_LENGTH_SHIFT, DST_LENGTH_MASK);
	DESC_ENC(desc, addr, DST_ADDR_SHIFT, DST_ADDR_MASK);

	return desc;
}

static u64 flexrm_mdst_desc(dma_addr_t addr, unsigned int length_div_16)
{
	u64 desc = 0;

	DESC_ENC(desc, MDST_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, length_div_16, MDST_LENGTH_SHIFT, MDST_LENGTH_MASK);
	DESC_ENC(desc, addr, MDST_ADDR_SHIFT, MDST_ADDR_MASK);

	return desc;
}

static u64 flexrm_imm_desc(u64 data)
{
	u64 desc = 0;

	DESC_ENC(desc, IMM_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, data, IMM_DATA_SHIFT, IMM_DATA_MASK);

	return desc;
}

static u64 flexrm_srct_desc(dma_addr_t addr, unsigned int length)
{
	u64 desc = 0;

	DESC_ENC(desc, SRCT_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, length, SRCT_LENGTH_SHIFT, SRCT_LENGTH_MASK);
	DESC_ENC(desc, addr, SRCT_ADDR_SHIFT, SRCT_ADDR_MASK);

	return desc;
}

static u64 flexrm_dstt_desc(dma_addr_t addr, unsigned int length)
{
	u64 desc = 0;

	DESC_ENC(desc, DSTT_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, length, DSTT_LENGTH_SHIFT, DSTT_LENGTH_MASK);
	DESC_ENC(desc, addr, DSTT_ADDR_SHIFT, DSTT_ADDR_MASK);

	return desc;
}

static u64 flexrm_immt_desc(u64 data)
{
	u64 desc = 0;

	DESC_ENC(desc, IMMT_TYPE, DESC_TYPE_SHIFT, DESC_TYPE_MASK);
	DESC_ENC(desc, data, IMMT_DATA_SHIFT, IMMT_DATA_MASK);

	return desc;
}

static bool flexrm_spu_sanity_check(struct brcm_message *msg)
{
	struct scatterlist *sg;

	if (!msg->spu.src || !msg->spu.dst)
		return false;
	for (sg = msg->spu.src; sg; sg = sg_next(sg)) {
		if (sg->length & 0xf) {
			if (sg->length > SRC_LENGTH_MASK)
				return false;
		} else {
			if (sg->length > (MSRC_LENGTH_MASK * 16))
				return false;
		}
	}
	for (sg = msg->spu.dst; sg; sg = sg_next(sg)) {
		if (sg->length & 0xf) {
			if (sg->length > DST_LENGTH_MASK)
				return false;
		} else {
			if (sg->length > (MDST_LENGTH_MASK * 16))
				return false;
		}
	}

	return true;
}

static u32 flexrm_spu_estimate_nonheader_desc_count(struct brcm_message *msg)
{
	u32 cnt = 0;
	unsigned int dst_target = 0;
	struct scatterlist *src_sg = msg->spu.src, *dst_sg = msg->spu.dst;

	while (src_sg || dst_sg) {
		if (src_sg) {
			cnt++;
			dst_target = src_sg->length;
			src_sg = sg_next(src_sg);
		} else
			dst_target = UINT_MAX;

		while (dst_target && dst_sg) {
			cnt++;
			if (dst_sg->length < dst_target)
				dst_target -= dst_sg->length;
			else
				dst_target = 0;
			dst_sg = sg_next(dst_sg);
		}
	}

	return cnt;
}

static int flexrm_spu_dma_map(struct device *dev, struct brcm_message *msg)
{
	int rc;

	rc = dma_map_sg(dev, msg->spu.src, sg_nents(msg->spu.src),
			DMA_TO_DEVICE);
	if (rc < 0)
		return rc;

	rc = dma_map_sg(dev, msg->spu.dst, sg_nents(msg->spu.dst),
			DMA_FROM_DEVICE);
	if (rc < 0) {
		dma_unmap_sg(dev, msg->spu.src, sg_nents(msg->spu.src),
			     DMA_TO_DEVICE);
		return rc;
	}

	return 0;
}

static void flexrm_spu_dma_unmap(struct device *dev, struct brcm_message *msg)
{
	dma_unmap_sg(dev, msg->spu.dst, sg_nents(msg->spu.dst),
		     DMA_FROM_DEVICE);
	dma_unmap_sg(dev, msg->spu.src, sg_nents(msg->spu.src),
		     DMA_TO_DEVICE);
}

static void *flexrm_spu_write_descs(struct brcm_message *msg, u32 nhcnt,
				     u32 reqid, void *desc_ptr, u32 toggle,
				     void *start_desc, void *end_desc)
{
	u64 d;
	u32 nhpos = 0;
	void *orig_desc_ptr = desc_ptr;
	unsigned int dst_target = 0;
	struct scatterlist *src_sg = msg->spu.src, *dst_sg = msg->spu.dst;

	while (src_sg || dst_sg) {
		if (src_sg) {
			if (sg_dma_len(src_sg) & 0xf)
				d = flexrm_src_desc(sg_dma_address(src_sg),
						     sg_dma_len(src_sg));
			else
				d = flexrm_msrc_desc(sg_dma_address(src_sg),
						      sg_dma_len(src_sg)/16);
			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
					     d, &desc_ptr, &toggle,
					     start_desc, end_desc);
			nhpos++;
			dst_target = sg_dma_len(src_sg);
			src_sg = sg_next(src_sg);
		} else
			dst_target = UINT_MAX;

		while (dst_target && dst_sg) {
			if (sg_dma_len(dst_sg) & 0xf)
				d = flexrm_dst_desc(sg_dma_address(dst_sg),
						     sg_dma_len(dst_sg));
			else
				d = flexrm_mdst_desc(sg_dma_address(dst_sg),
						      sg_dma_len(dst_sg)/16);
			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
					     d, &desc_ptr, &toggle,
					     start_desc, end_desc);
			nhpos++;
			if (sg_dma_len(dst_sg) < dst_target)
				dst_target -= sg_dma_len(dst_sg);
			else
				dst_target = 0;
			dst_sg = sg_next(dst_sg);
		}
	}

	/* Null descriptor with invalid toggle bit */
	flexrm_write_desc(desc_ptr, flexrm_null_desc(!toggle));

	/* Ensure that descriptors have been written to memory */
	wmb();

	/* Flip toggle bit in header */
	flexrm_flip_header_toogle(orig_desc_ptr);

	return desc_ptr;
}

static bool flexrm_sba_sanity_check(struct brcm_message *msg)
{
	u32 i;

	if (!msg->sba.cmds || !msg->sba.cmds_count)
		return false;

	for (i = 0; i < msg->sba.cmds_count; i++) {
		if (((msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_B) ||
		     (msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_C)) &&
		    (msg->sba.cmds[i].flags & BRCM_SBA_CMD_HAS_OUTPUT))
			return false;
		if ((msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_B) &&
		    (msg->sba.cmds[i].data_len > SRCT_LENGTH_MASK))
			return false;
		if ((msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_C) &&
		    (msg->sba.cmds[i].data_len > SRCT_LENGTH_MASK))
			return false;
		if ((msg->sba.cmds[i].flags & BRCM_SBA_CMD_HAS_RESP) &&
		    (msg->sba.cmds[i].resp_len > DSTT_LENGTH_MASK))
			return false;
		if ((msg->sba.cmds[i].flags & BRCM_SBA_CMD_HAS_OUTPUT) &&
		    (msg->sba.cmds[i].data_len > DSTT_LENGTH_MASK))
			return false;
	}

	return true;
}

static u32 flexrm_sba_estimate_nonheader_desc_count(struct brcm_message *msg)
{
	u32 i, cnt;

	cnt = 0;
	for (i = 0; i < msg->sba.cmds_count; i++) {
		cnt++;

		if ((msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_B) ||
		    (msg->sba.cmds[i].flags & BRCM_SBA_CMD_TYPE_C))
			cnt++;

		if (msg->sba.cmds[i].flags & BRCM_SBA_CMD_HAS_RESP)
			cnt++;

		if (msg->sba.cmds[i].flags & BRCM_SBA_CMD_HAS_OUTPUT)
			cnt++;
	}

	return cnt;
}

static void *flexrm_sba_write_descs(struct brcm_message *msg, u32 nhcnt,
				     u32 reqid, void *desc_ptr, u32 toggle,
				     void *start_desc, void *end_desc)
{
	u64 d;
	u32 i, nhpos = 0;
	struct brcm_sba_command *c;
	void *orig_desc_ptr = desc_ptr;

	/* Convert SBA commands into descriptors */
	for (i = 0; i < msg->sba.cmds_count; i++) {
		c = &msg->sba.cmds[i];

		if ((c->flags & BRCM_SBA_CMD_HAS_RESP) &&
		    (c->flags & BRCM_SBA_CMD_HAS_OUTPUT)) {
			/* Destination response descriptor */
			d = flexrm_dst_desc(c->resp, c->resp_len);
			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
					     d, &desc_ptr, &toggle,
					     start_desc, end_desc);
			nhpos++;
		} else if (c->flags & BRCM_SBA_CMD_HAS_RESP) {
			/* Destination response with tlast descriptor */
			d = flexrm_dstt_desc(c->resp, c->resp_len);
			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
					     d, &desc_ptr, &toggle,
					     start_desc, end_desc);
			nhpos++;
		}

		if (c->flags & BRCM_SBA_CMD_HAS_OUTPUT) {
			/* Destination with tlast descriptor */
			d = flexrm_dstt_desc(c->data, c->data_len);
			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
					     d, &desc_ptr, &toggle,
					     start_desc, end_desc);
			nhpos++;
		}

		if (c->flags & BRCM_SBA_CMD_TYPE_B) {
			/* Command as immediate descriptor */
			d = flexrm_imm_desc(c->cmd);
			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
					     d, &desc_ptr, &toggle,
					     start_desc, end_desc);
			nhpos++;
		} else {
			/* Command as immediate descriptor with tlast */
			d = flexrm_immt_desc(c->cmd);
			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
					     d, &desc_ptr, &toggle,
					     start_desc, end_desc);
			nhpos++;
		}

		if ((c->flags & BRCM_SBA_CMD_TYPE_B) ||
		    (c->flags & BRCM_SBA_CMD_TYPE_C)) {
			/* Source with tlast descriptor */
			d = flexrm_srct_desc(c->data, c->data_len);
			flexrm_enqueue_desc(nhpos, nhcnt, reqid,
					     d, &desc_ptr, &toggle,
					     start_desc, end_desc);
			nhpos++;
		}
	}

	/* Null descriptor with invalid toggle bit */
	flexrm_write_desc(desc_ptr, flexrm_null_desc(!toggle));

	/* Ensure that descriptors have been written to memory */
	wmb();

	/* Flip toggle bit in header */
	flexrm_flip_header_toogle(orig_desc_ptr);

	return desc_ptr;
}

static bool flexrm_sanity_check(struct brcm_message *msg)
{
	if (!msg)
		return false;

	switch (msg->type) {
	case BRCM_MESSAGE_SPU:
		return flexrm_spu_sanity_check(msg);
	case BRCM_MESSAGE_SBA:
		return flexrm_sba_sanity_check(msg);
	default:
		return false;
	};
}

static u32 flexrm_estimate_nonheader_desc_count(struct brcm_message *msg)
{
	if (!msg)
		return 0;

	switch (msg->type) {
	case BRCM_MESSAGE_SPU:
		return flexrm_spu_estimate_nonheader_desc_count(msg);
	case BRCM_MESSAGE_SBA:
		return flexrm_sba_estimate_nonheader_desc_count(msg);
	default:
		return 0;
	};
}

static int flexrm_dma_map(struct device *dev, struct brcm_message *msg)
{
	if (!dev || !msg)
		return -EINVAL;

	switch (msg->type) {
	case BRCM_MESSAGE_SPU:
		return flexrm_spu_dma_map(dev, msg);
	default:
		break;
	}

	return 0;
}

static void flexrm_dma_unmap(struct device *dev, struct brcm_message *msg)
{
	if (!dev || !msg)
		return;

	switch (msg->type) {
	case BRCM_MESSAGE_SPU:
		flexrm_spu_dma_unmap(dev, msg);
		break;
	default:
		break;
	}
}

static void *flexrm_write_descs(struct brcm_message *msg, u32 nhcnt,
				u32 reqid, void *desc_ptr, u32 toggle,
				void *start_desc, void *end_desc)
{
	if (!msg || !desc_ptr || !start_desc || !end_desc)
		return ERR_PTR(-ENOTSUPP);

	if ((desc_ptr < start_desc) || (end_desc <= desc_ptr))
		return ERR_PTR(-ERANGE);

	switch (msg->type) {
	case BRCM_MESSAGE_SPU:
		return flexrm_spu_write_descs(msg, nhcnt, reqid,
					       desc_ptr, toggle,
					       start_desc, end_desc);
	case BRCM_MESSAGE_SBA:
		return flexrm_sba_write_descs(msg, nhcnt, reqid,
					       desc_ptr, toggle,
					       start_desc, end_desc);
	default:
		return ERR_PTR(-ENOTSUPP);
	};
}

/* ====== FlexRM driver helper routines ===== */

static int flexrm_new_request(struct flexrm_ring *ring,
				struct brcm_message *batch_msg,
				struct brcm_message *msg)
{
	void *next;
	unsigned long flags;
	u32 val, count, nhcnt;
	u32 read_offset, write_offset;
	bool exit_cleanup = false;
	int ret = 0, reqid;

	/* Do sanity check on message */
	if (!flexrm_sanity_check(msg))
		return -EIO;
	msg->error = 0;

	/* If no requests possible then save data pointer and goto done. */
	reqid = ida_simple_get(&ring->requests_ida, 0,
				RING_MAX_REQ_COUNT, GFP_KERNEL);
	if (reqid < 0) {
		spin_lock_irqsave(&ring->lock, flags);
		if (batch_msg)
			ring->last_pending_msg = batch_msg;
		else
			ring->last_pending_msg = msg;
		spin_unlock_irqrestore(&ring->lock, flags);
		return 0;
	}
	ring->requests[reqid] = msg;

	/* Do DMA mappings for the message */
	ret = flexrm_dma_map(ring->mbox->dev, msg);
	if (ret < 0) {
		ring->requests[reqid] = NULL;
		ida_simple_remove(&ring->requests_ida, reqid);
		return ret;
	}

	/* If last_pending_msg is already set then goto done with error */
	spin_lock_irqsave(&ring->lock, flags);
	if (ring->last_pending_msg)
		ret = -ENOSPC;
	spin_unlock_irqrestore(&ring->lock, flags);
	if (ret < 0) {
		dev_warn(ring->mbox->dev, "no space in ring %d\n", ring->num);
		exit_cleanup = true;
		goto exit;
	}

	/* Determine current HW BD read offset */
	read_offset = readl_relaxed(ring->regs + RING_BD_READ_PTR);
	val = readl_relaxed(ring->regs + RING_BD_START_ADDR);
	read_offset *= RING_DESC_SIZE;
	read_offset += (u32)(BD_START_ADDR_DECODE(val) - ring->bd_dma_base);

	/*
	 * Number required descriptors = number of non-header descriptors +
	 *				 number of header descriptors +
	 *				 1x null descriptor
	 */
	nhcnt = flexrm_estimate_nonheader_desc_count(msg);
	count = flexrm_estimate_header_desc_count(nhcnt) + nhcnt + 1;

	/* Check for available descriptor space. */
	write_offset = ring->bd_write_offset;
	while (count) {
		if (!flexrm_is_next_table_desc(ring->bd_base + write_offset))
			count--;
		write_offset += RING_DESC_SIZE;
		if (write_offset == RING_BD_SIZE)
			write_offset = 0x0;
		if (write_offset == read_offset)
			break;
	}
	if (count) {
		spin_lock_irqsave(&ring->lock, flags);
		if (batch_msg)
			ring->last_pending_msg = batch_msg;
		else
			ring->last_pending_msg = msg;
		spin_unlock_irqrestore(&ring->lock, flags);
		ret = 0;
		exit_cleanup = true;
		goto exit;
	}

	/* Write descriptors to ring */
	next = flexrm_write_descs(msg, nhcnt, reqid,
			ring->bd_base + ring->bd_write_offset,
			RING_BD_TOGGLE_VALID(ring->bd_write_offset),
			ring->bd_base, ring->bd_base + RING_BD_SIZE);
	if (IS_ERR(next)) {
		ret = PTR_ERR(next);
		exit_cleanup = true;
		goto exit;
	}

	/* Save ring BD write offset */
	ring->bd_write_offset = (unsigned long)(next - ring->bd_base);

exit:
	/* Update error status in message */
	msg->error = ret;

	/* Cleanup if we failed */
	if (exit_cleanup) {
		flexrm_dma_unmap(ring->mbox->dev, msg);
		ring->requests[reqid] = NULL;
		ida_simple_remove(&ring->requests_ida, reqid);
	}

	return ret;
}

static int flexrm_process_completions(struct flexrm_ring *ring)
{
	u64 desc;
	int err, count = 0;
	unsigned long flags;
	struct brcm_message *msg = NULL;
	u32 reqid, cmpl_read_offset, cmpl_write_offset;
	struct mbox_chan *chan = &ring->mbox->controller.chans[ring->num];

	spin_lock_irqsave(&ring->lock, flags);

	/* Check last_pending_msg */
	if (ring->last_pending_msg) {
		msg = ring->last_pending_msg;
		ring->last_pending_msg = NULL;
	}

	/*
	 * Get current completion read and write offset
	 *
	 * Note: We should read completion write pointer atleast once
	 * after we get a MSI interrupt because HW maintains internal
	 * MSI status which will allow next MSI interrupt only after
	 * completion write pointer is read.
	 */
	cmpl_write_offset = readl_relaxed(ring->regs + RING_CMPL_WRITE_PTR);
	cmpl_write_offset *= RING_DESC_SIZE;
	cmpl_read_offset = ring->cmpl_read_offset;
	ring->cmpl_read_offset = cmpl_write_offset;

	spin_unlock_irqrestore(&ring->lock, flags);

	/* If last_pending_msg was set then queue it back */
	if (msg)
		mbox_send_message(chan, msg);

	/* For each completed request notify mailbox clients */
	reqid = 0;
	while (cmpl_read_offset != cmpl_write_offset) {
		/* Dequeue next completion descriptor */
		desc = *((u64 *)(ring->cmpl_base + cmpl_read_offset));

		/* Next read offset */
		cmpl_read_offset += RING_DESC_SIZE;
		if (cmpl_read_offset == RING_CMPL_SIZE)
			cmpl_read_offset = 0;

		/* Decode error from completion descriptor */
		err = flexrm_cmpl_desc_to_error(desc);
		if (err < 0) {
			dev_warn(ring->mbox->dev,
				 "got completion desc=0x%lx with error %d",
				 (unsigned long)desc, err);
		}

		/* Determine request id from completion descriptor */
		reqid = flexrm_cmpl_desc_to_reqid(desc);

		/* Determine message pointer based on reqid */
		msg = ring->requests[reqid];
		if (!msg) {
			dev_warn(ring->mbox->dev,
				 "null msg pointer for completion desc=0x%lx",
				 (unsigned long)desc);
			continue;
		}

		/* Release reqid for recycling */
		ring->requests[reqid] = NULL;
		ida_simple_remove(&ring->requests_ida, reqid);

		/* Unmap DMA mappings */
		flexrm_dma_unmap(ring->mbox->dev, msg);

		/* Give-back message to mailbox client */
		msg->error = err;
		mbox_chan_received_data(chan, msg);

		/* Increment number of completions processed */
		count++;
	}

	return count;
}

/* ====== FlexRM interrupt handler ===== */

static irqreturn_t flexrm_irq_event(int irq, void *dev_id)
{
	/* We only have MSI for completions so just wakeup IRQ thread */
	/* Ring related errors will be informed via completion descriptors */

	return IRQ_WAKE_THREAD;
}

static irqreturn_t flexrm_irq_thread(int irq, void *dev_id)
{
	flexrm_process_completions(dev_id);

	return IRQ_HANDLED;
}

/* ====== FlexRM mailbox callbacks ===== */

static int flexrm_send_data(struct mbox_chan *chan, void *data)
{
	int i, rc;
	struct flexrm_ring *ring = chan->con_priv;
	struct brcm_message *msg = data;

	if (msg->type == BRCM_MESSAGE_BATCH) {
		for (i = msg->batch.msgs_queued;
		     i < msg->batch.msgs_count; i++) {
			rc = flexrm_new_request(ring, msg,
						 &msg->batch.msgs[i]);
			if (rc) {
				msg->error = rc;
				return rc;
			}
			msg->batch.msgs_queued++;
		}
		return 0;
	}

	return flexrm_new_request(ring, NULL, data);
}

static bool flexrm_peek_data(struct mbox_chan *chan)
{
	int cnt = flexrm_process_completions(chan->con_priv);

	return (cnt > 0) ? true : false;
}

static int flexrm_startup(struct mbox_chan *chan)
{
	u64 d;
	u32 val, off;
	int ret = 0;
	dma_addr_t next_addr;
	struct flexrm_ring *ring = chan->con_priv;

	/* Allocate BD memory */
	ring->bd_base = dma_pool_alloc(ring->mbox->bd_pool,
				       GFP_KERNEL, &ring->bd_dma_base);
	if (!ring->bd_base) {
		dev_err(ring->mbox->dev, "can't allocate BD memory\n");
		ret = -ENOMEM;
		goto fail;
	}

	/* Configure next table pointer entries in BD memory */
	for (off = 0; off < RING_BD_SIZE; off += RING_DESC_SIZE) {
		next_addr = off + RING_DESC_SIZE;
		if (next_addr == RING_BD_SIZE)
			next_addr = 0;
		next_addr += ring->bd_dma_base;
		if (RING_BD_ALIGN_CHECK(next_addr))
			d = flexrm_next_table_desc(RING_BD_TOGGLE_VALID(off),
						    next_addr);
		else
			d = flexrm_null_desc(RING_BD_TOGGLE_INVALID(off));
		flexrm_write_desc(ring->bd_base + off, d);
	}

	/* Allocate completion memory */
	ring->cmpl_base = dma_pool_alloc(ring->mbox->cmpl_pool,
					 GFP_KERNEL, &ring->cmpl_dma_base);
	if (!ring->cmpl_base) {
		dev_err(ring->mbox->dev, "can't allocate completion memory\n");
		ret = -ENOMEM;
		goto fail_free_bd_memory;
	}
	memset(ring->cmpl_base, 0, RING_CMPL_SIZE);

	/* Request IRQ */
	if (ring->irq == UINT_MAX) {
		dev_err(ring->mbox->dev, "ring IRQ not available\n");
		ret = -ENODEV;
		goto fail_free_cmpl_memory;
	}
	ret = request_threaded_irq(ring->irq,
				   flexrm_irq_event,
				   flexrm_irq_thread,
				   0, dev_name(ring->mbox->dev), ring);
	if (ret) {
		dev_err(ring->mbox->dev, "failed to request ring IRQ\n");
		goto fail_free_cmpl_memory;
	}
	ring->irq_requested = true;

	/* Disable/inactivate ring */
	writel_relaxed(0x0, ring->regs + RING_CONTROL);

	/* Program BD start address */
	val = BD_START_ADDR_VALUE(ring->bd_dma_base);
	writel_relaxed(val, ring->regs + RING_BD_START_ADDR);

	/* BD write pointer will be same as HW write pointer */
	ring->bd_write_offset =
			readl_relaxed(ring->regs + RING_BD_WRITE_PTR);
	ring->bd_write_offset *= RING_DESC_SIZE;

	/* Program completion start address */
	val = CMPL_START_ADDR_VALUE(ring->cmpl_dma_base);
	writel_relaxed(val, ring->regs + RING_CMPL_START_ADDR);

	/* Ensure last pending message is cleared */
	ring->last_pending_msg = NULL;

	/* Completion read pointer will be same as HW write pointer */
	ring->cmpl_read_offset =
			readl_relaxed(ring->regs + RING_CMPL_WRITE_PTR);
	ring->cmpl_read_offset *= RING_DESC_SIZE;

	/* Read ring Tx, Rx, and Outstanding counts to clear */
	readl_relaxed(ring->regs + RING_NUM_REQ_RECV_LS);
	readl_relaxed(ring->regs + RING_NUM_REQ_RECV_MS);
	readl_relaxed(ring->regs + RING_NUM_REQ_TRANS_LS);
	readl_relaxed(ring->regs + RING_NUM_REQ_TRANS_MS);
	readl_relaxed(ring->regs + RING_NUM_REQ_OUTSTAND);

	/* Configure RING_MSI_CONTROL */
	val = 0;
	val |= (ring->msi_timer_val << MSI_TIMER_VAL_SHIFT);
	val |= BIT(MSI_ENABLE_SHIFT);
	val |= (ring->msi_count_threshold & MSI_COUNT_MASK) << MSI_COUNT_SHIFT;
	writel_relaxed(val, ring->regs + RING_MSI_CONTROL);

	/* Enable/activate ring */
	val = BIT(CONTROL_ACTIVE_SHIFT);
	writel_relaxed(val, ring->regs + RING_CONTROL);

	return 0;

fail_free_cmpl_memory:
	dma_pool_free(ring->mbox->cmpl_pool,
		      ring->cmpl_base, ring->cmpl_dma_base);
	ring->cmpl_base = NULL;
fail_free_bd_memory:
	dma_pool_free(ring->mbox->bd_pool,
		      ring->bd_base, ring->bd_dma_base);
	ring->bd_base = NULL;
fail:
	return ret;
}

static void flexrm_shutdown(struct mbox_chan *chan)
{
	u32 reqid;
	unsigned int timeout;
	struct brcm_message *msg;
	struct flexrm_ring *ring = chan->con_priv;

	/* Disable/inactivate ring */
	writel_relaxed(0x0, ring->regs + RING_CONTROL);

	/* Flush ring with timeout of 1s */
	timeout = 1000;
	writel_relaxed(BIT(CONTROL_FLUSH_SHIFT),
			ring->regs + RING_CONTROL);
	do {
		if (readl_relaxed(ring->regs + RING_FLUSH_DONE) &
		    FLUSH_DONE_MASK)
			break;
		mdelay(1);
	} while (timeout--);

	/* Abort all in-flight requests */
	for (reqid = 0; reqid < RING_MAX_REQ_COUNT; reqid++) {
		msg = ring->requests[reqid];
		if (!msg)
			continue;

		/* Release reqid for recycling */
		ring->requests[reqid] = NULL;
		ida_simple_remove(&ring->requests_ida, reqid);

		/* Unmap DMA mappings */
		flexrm_dma_unmap(ring->mbox->dev, msg);

		/* Give-back message to mailbox client */
		msg->error = -EIO;
		mbox_chan_received_data(chan, msg);
	}

	/* Release IRQ */
	if (ring->irq_requested) {
		free_irq(ring->irq, ring);
		ring->irq_requested = false;
	}

	/* Free-up completion descriptor ring */
	if (ring->cmpl_base) {
		dma_pool_free(ring->mbox->cmpl_pool,
			      ring->cmpl_base, ring->cmpl_dma_base);
		ring->cmpl_base = NULL;
	}

	/* Free-up BD descriptor ring */
	if (ring->bd_base) {
		dma_pool_free(ring->mbox->bd_pool,
			      ring->bd_base, ring->bd_dma_base);
		ring->bd_base = NULL;
	}
}

static bool flexrm_last_tx_done(struct mbox_chan *chan)
{
	bool ret;
	unsigned long flags;
	struct flexrm_ring *ring = chan->con_priv;

	spin_lock_irqsave(&ring->lock, flags);
	ret = (ring->last_pending_msg) ? false : true;
	spin_unlock_irqrestore(&ring->lock, flags);

	return ret;
}

static const struct mbox_chan_ops flexrm_mbox_chan_ops = {
	.send_data	= flexrm_send_data,
	.startup	= flexrm_startup,
	.shutdown	= flexrm_shutdown,
	.last_tx_done	= flexrm_last_tx_done,
	.peek_data	= flexrm_peek_data,
};

static struct mbox_chan *flexrm_mbox_of_xlate(struct mbox_controller *cntlr,
					const struct of_phandle_args *pa)
{
	struct mbox_chan *chan;
	struct flexrm_ring *ring;

	if (pa->args_count < 3)
		return ERR_PTR(-EINVAL);

	if (pa->args[0] >= cntlr->num_chans)
		return ERR_PTR(-ENOENT);

	if (pa->args[1] > MSI_COUNT_MASK)
		return ERR_PTR(-EINVAL);

	if (pa->args[2] > MSI_TIMER_VAL_MASK)
		return ERR_PTR(-EINVAL);

	chan = &cntlr->chans[pa->args[0]];
	ring = chan->con_priv;
	ring->msi_count_threshold = pa->args[1];
	ring->msi_timer_val = pa->args[2];

	return chan;
}

/* ====== FlexRM platform driver ===== */

static void flexrm_mbox_msi_write(struct msi_desc *desc, struct msi_msg *msg)
{
	struct device *dev = msi_desc_to_dev(desc);
	struct flexrm_mbox *mbox = dev_get_drvdata(dev);
	struct flexrm_ring *ring = &mbox->rings[desc->platform.msi_index];

	/* Configure per-Ring MSI registers */
	writel_relaxed(msg->address_lo, ring->regs + RING_MSI_ADDR_LS);
	writel_relaxed(msg->address_hi, ring->regs + RING_MSI_ADDR_MS);
	writel_relaxed(msg->data, ring->regs + RING_MSI_DATA_VALUE);
}

static int flexrm_mbox_probe(struct platform_device *pdev)
{
	int index, ret = 0;
	void __iomem *regs;
	void __iomem *regs_end;
	struct msi_desc *desc;
	struct resource *iomem;
	struct flexrm_ring *ring;
	struct flexrm_mbox *mbox;
	struct device *dev = &pdev->dev;

	/* Allocate driver mailbox struct */
	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
	if (!mbox) {
		ret = -ENOMEM;
		goto fail;
	}
	mbox->dev = dev;
	platform_set_drvdata(pdev, mbox);

	/* Get resource for registers */
	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!iomem || (resource_size(iomem) < RING_REGS_SIZE)) {
		ret = -ENODEV;
		goto fail;
	}

	/* Map registers of all rings */
	mbox->regs = devm_ioremap_resource(&pdev->dev, iomem);
	if (IS_ERR(mbox->regs)) {
		ret = PTR_ERR(mbox->regs);
		dev_err(&pdev->dev, "Failed to remap mailbox regs: %d\n", ret);
		goto fail;
	}
	regs_end = mbox->regs + resource_size(iomem);

	/* Scan and count available rings */
	mbox->num_rings = 0;
	for (regs = mbox->regs; regs < regs_end; regs += RING_REGS_SIZE) {
		if (readl_relaxed(regs + RING_VER) == RING_VER_MAGIC)
			mbox->num_rings++;
	}
	if (!mbox->num_rings) {
		ret = -ENODEV;
		goto fail;
	}

	/* Allocate driver ring structs */
	ring = devm_kcalloc(dev, mbox->num_rings, sizeof(*ring), GFP_KERNEL);
	if (!ring) {
		ret = -ENOMEM;
		goto fail;
	}
	mbox->rings = ring;

	/* Initialize members of driver ring structs */
	regs = mbox->regs;
	for (index = 0; index < mbox->num_rings; index++) {
		ring = &mbox->rings[index];
		ring->num = index;
		ring->mbox = mbox;
		while ((regs < regs_end) &&
		       (readl_relaxed(regs + RING_VER) != RING_VER_MAGIC))
			regs += RING_REGS_SIZE;
		if (regs_end <= regs) {
			ret = -ENODEV;
			goto fail;
		}
		ring->regs = regs;
		regs += RING_REGS_SIZE;
		ring->irq = UINT_MAX;
		ring->irq_requested = false;
		ring->msi_timer_val = MSI_TIMER_VAL_MASK;
		ring->msi_count_threshold = 0x1;
		ida_init(&ring->requests_ida);
		memset(ring->requests, 0, sizeof(ring->requests));
		ring->bd_base = NULL;
		ring->bd_dma_base = 0;
		ring->cmpl_base = NULL;
		ring->cmpl_dma_base = 0;
		spin_lock_init(&ring->lock);
		ring->last_pending_msg = NULL;
		ring->cmpl_read_offset = 0;
	}

	/* FlexRM is capable of 40-bit physical addresses only */
	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(40));
	if (ret) {
		ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
		if (ret)
			goto fail;
	}

	/* Create DMA pool for ring BD memory */
	mbox->bd_pool = dma_pool_create("bd", dev, RING_BD_SIZE,
					1 << RING_BD_ALIGN_ORDER, 0);
	if (!mbox->bd_pool) {
		ret = -ENOMEM;
		goto fail;
	}

	/* Create DMA pool for ring completion memory */
	mbox->cmpl_pool = dma_pool_create("cmpl", dev, RING_CMPL_SIZE,
					  1 << RING_CMPL_ALIGN_ORDER, 0);
	if (!mbox->cmpl_pool) {
		ret = -ENOMEM;
		goto fail_destroy_bd_pool;
	}

	/* Allocate platform MSIs for each ring */
	ret = platform_msi_domain_alloc_irqs(dev, mbox->num_rings,
						flexrm_mbox_msi_write);
	if (ret)
		goto fail_destroy_cmpl_pool;

	/* Save alloced IRQ numbers for each ring */
	for_each_msi_entry(desc, dev) {
		ring = &mbox->rings[desc->platform.msi_index];
		ring->irq = desc->irq;
	}

	/* Initialize mailbox controller */
	mbox->controller.txdone_irq = false;
	mbox->controller.txdone_poll = true;
	mbox->controller.txpoll_period = 1;
	mbox->controller.ops = &flexrm_mbox_chan_ops;
	mbox->controller.dev = dev;
	mbox->controller.num_chans = mbox->num_rings;
	mbox->controller.of_xlate = flexrm_mbox_of_xlate;
	mbox->controller.chans = devm_kcalloc(dev, mbox->num_rings,
				sizeof(*mbox->controller.chans), GFP_KERNEL);
	if (!mbox->controller.chans) {
		ret = -ENOMEM;
		goto fail_free_msis;
	}
	for (index = 0; index < mbox->num_rings; index++)
		mbox->controller.chans[index].con_priv = &mbox->rings[index];

	/* Register mailbox controller */
	ret = mbox_controller_register(&mbox->controller);
	if (ret)
		goto fail_free_msis;

	dev_info(dev, "registered flexrm mailbox with %d channels\n",
			mbox->controller.num_chans);

	return 0;

fail_free_msis:
	platform_msi_domain_free_irqs(dev);
fail_destroy_cmpl_pool:
	dma_pool_destroy(mbox->cmpl_pool);
fail_destroy_bd_pool:
	dma_pool_destroy(mbox->bd_pool);
fail:
	return ret;
}

static int flexrm_mbox_remove(struct platform_device *pdev)
{
	int index;
	struct device *dev = &pdev->dev;
	struct flexrm_ring *ring;
	struct flexrm_mbox *mbox = platform_get_drvdata(pdev);

	mbox_controller_unregister(&mbox->controller);

	platform_msi_domain_free_irqs(dev);

	dma_pool_destroy(mbox->cmpl_pool);
	dma_pool_destroy(mbox->bd_pool);

	for (index = 0; index < mbox->num_rings; index++) {
		ring = &mbox->rings[index];
		ida_destroy(&ring->requests_ida);
	}

	return 0;
}

static const struct of_device_id flexrm_mbox_of_match[] = {
	{ .compatible = "brcm,iproc-flexrm-mbox", },
	{},
};
MODULE_DEVICE_TABLE(of, flexrm_mbox_of_match);

static struct platform_driver flexrm_mbox_driver = {
	.driver = {
		.name = "brcm-flexrm-mbox",
		.of_match_table = flexrm_mbox_of_match,
	},
	.probe		= flexrm_mbox_probe,
	.remove		= flexrm_mbox_remove,
};
module_platform_driver(flexrm_mbox_driver);

MODULE_AUTHOR("Anup Patel <anup.patel@broadcom.com>");
MODULE_DESCRIPTION("Broadcom FlexRM mailbox driver");
MODULE_LICENSE("GPL v2");