summaryrefslogtreecommitdiff
path: root/drivers/tty/serial/8250/8250_bcm7271.c
blob: fa8ccf204d860223e4c5339791295e43d9575e9b (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
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2020, Broadcom */
/*
 * 8250-core based driver for Broadcom ns16550a UARTs
 *
 * This driver uses the standard 8250 driver core but adds additional
 * optional features including the ability to use a baud rate clock
 * mux for more accurate high speed baud rate selection and also
 * an optional DMA engine.
 *
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/dma-mapping.h>
#include <linux/tty_flip.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/debugfs.h>

#include "8250.h"

/* Register definitions for UART DMA block. Version 1.1 or later. */
#define UDMA_ARB_RX		0x00
#define UDMA_ARB_TX		0x04
#define		UDMA_ARB_REQ				0x00000001
#define		UDMA_ARB_GRANT				0x00000002

#define UDMA_RX_REVISION	0x00
#define UDMA_RX_REVISION_REQUIRED			0x00000101
#define UDMA_RX_CTRL		0x04
#define		UDMA_RX_CTRL_BUF_CLOSE_MODE		0x00010000
#define		UDMA_RX_CTRL_MASK_WR_DONE		0x00008000
#define		UDMA_RX_CTRL_ENDIAN_OVERRIDE		0x00004000
#define		UDMA_RX_CTRL_ENDIAN			0x00002000
#define		UDMA_RX_CTRL_OE_IS_ERR			0x00001000
#define		UDMA_RX_CTRL_PE_IS_ERR			0x00000800
#define		UDMA_RX_CTRL_FE_IS_ERR			0x00000400
#define		UDMA_RX_CTRL_NUM_BUF_USED_MASK		0x000003c0
#define		UDMA_RX_CTRL_NUM_BUF_USED_SHIFT	6
#define		UDMA_RX_CTRL_BUF_CLOSE_CLK_SEL_SYS	0x00000020
#define		UDMA_RX_CTRL_BUF_CLOSE_ENA		0x00000010
#define		UDMA_RX_CTRL_TIMEOUT_CLK_SEL_SYS	0x00000008
#define		UDMA_RX_CTRL_TIMEOUT_ENA		0x00000004
#define		UDMA_RX_CTRL_ABORT			0x00000002
#define		UDMA_RX_CTRL_ENA			0x00000001
#define UDMA_RX_STATUS		0x08
#define		UDMA_RX_STATUS_ACTIVE_BUF_MASK		0x0000000f
#define UDMA_RX_TRANSFER_LEN	0x0c
#define UDMA_RX_TRANSFER_TOTAL	0x10
#define UDMA_RX_BUFFER_SIZE	0x14
#define UDMA_RX_SRC_ADDR	0x18
#define UDMA_RX_TIMEOUT		0x1c
#define UDMA_RX_BUFFER_CLOSE	0x20
#define UDMA_RX_BLOCKOUT_COUNTER 0x24
#define UDMA_RX_BUF0_PTR_LO	0x28
#define UDMA_RX_BUF0_PTR_HI	0x2c
#define UDMA_RX_BUF0_STATUS	0x30
#define		UDMA_RX_BUFX_STATUS_OVERRUN_ERR		0x00000010
#define		UDMA_RX_BUFX_STATUS_FRAME_ERR		0x00000008
#define		UDMA_RX_BUFX_STATUS_PARITY_ERR		0x00000004
#define		UDMA_RX_BUFX_STATUS_CLOSE_EXPIRED	0x00000002
#define		UDMA_RX_BUFX_STATUS_DATA_RDY		0x00000001
#define UDMA_RX_BUF0_DATA_LEN	0x34
#define UDMA_RX_BUF1_PTR_LO	0x38
#define UDMA_RX_BUF1_PTR_HI	0x3c
#define UDMA_RX_BUF1_STATUS	0x40
#define UDMA_RX_BUF1_DATA_LEN	0x44

#define UDMA_TX_REVISION	0x00
#define UDMA_TX_REVISION_REQUIRED			0x00000101
#define UDMA_TX_CTRL		0x04
#define		UDMA_TX_CTRL_ENDIAN_OVERRIDE		0x00000080
#define		UDMA_TX_CTRL_ENDIAN			0x00000040
#define		UDMA_TX_CTRL_NUM_BUF_USED_MASK		0x00000030
#define		UDMA_TX_CTRL_NUM_BUF_USED_1		0x00000010
#define		UDMA_TX_CTRL_ABORT			0x00000002
#define		UDMA_TX_CTRL_ENA			0x00000001
#define UDMA_TX_DST_ADDR	0x08
#define UDMA_TX_BLOCKOUT_COUNTER 0x10
#define UDMA_TX_TRANSFER_LEN	0x14
#define UDMA_TX_TRANSFER_TOTAL	0x18
#define UDMA_TX_STATUS		0x20
#define UDMA_TX_BUF0_PTR_LO	0x24
#define UDMA_TX_BUF0_PTR_HI	0x28
#define UDMA_TX_BUF0_STATUS	0x2c
#define		UDMA_TX_BUFX_LAST			0x00000002
#define		UDMA_TX_BUFX_EMPTY			0x00000001
#define UDMA_TX_BUF0_DATA_LEN	0x30
#define UDMA_TX_BUF0_DATA_SENT	0x34
#define UDMA_TX_BUF1_PTR_LO	0x38

#define UDMA_INTR_STATUS	0x00
#define		UDMA_INTR_ARB_TX_GRANT			0x00040000
#define		UDMA_INTR_ARB_RX_GRANT			0x00020000
#define		UDMA_INTR_TX_ALL_EMPTY			0x00010000
#define		UDMA_INTR_TX_EMPTY_BUF1			0x00008000
#define		UDMA_INTR_TX_EMPTY_BUF0			0x00004000
#define		UDMA_INTR_TX_ABORT			0x00002000
#define		UDMA_INTR_TX_DONE			0x00001000
#define		UDMA_INTR_RX_ERROR			0x00000800
#define		UDMA_INTR_RX_TIMEOUT			0x00000400
#define		UDMA_INTR_RX_READY_BUF7			0x00000200
#define		UDMA_INTR_RX_READY_BUF6			0x00000100
#define		UDMA_INTR_RX_READY_BUF5			0x00000080
#define		UDMA_INTR_RX_READY_BUF4			0x00000040
#define		UDMA_INTR_RX_READY_BUF3			0x00000020
#define		UDMA_INTR_RX_READY_BUF2			0x00000010
#define		UDMA_INTR_RX_READY_BUF1			0x00000008
#define		UDMA_INTR_RX_READY_BUF0			0x00000004
#define		UDMA_INTR_RX_READY_MASK			0x000003fc
#define		UDMA_INTR_RX_READY_SHIFT		2
#define		UDMA_INTR_RX_ABORT			0x00000002
#define		UDMA_INTR_RX_DONE			0x00000001
#define UDMA_INTR_SET		0x04
#define UDMA_INTR_CLEAR		0x08
#define UDMA_INTR_MASK_STATUS	0x0c
#define UDMA_INTR_MASK_SET	0x10
#define UDMA_INTR_MASK_CLEAR	0x14


#define UDMA_RX_INTERRUPTS ( \
	UDMA_INTR_RX_ERROR | \
	UDMA_INTR_RX_TIMEOUT | \
	UDMA_INTR_RX_READY_BUF0 | \
	UDMA_INTR_RX_READY_BUF1 | \
	UDMA_INTR_RX_READY_BUF2 | \
	UDMA_INTR_RX_READY_BUF3 | \
	UDMA_INTR_RX_READY_BUF4 | \
	UDMA_INTR_RX_READY_BUF5 | \
	UDMA_INTR_RX_READY_BUF6 | \
	UDMA_INTR_RX_READY_BUF7 | \
	UDMA_INTR_RX_ABORT | \
	UDMA_INTR_RX_DONE)

#define UDMA_RX_ERR_INTERRUPTS ( \
	UDMA_INTR_RX_ERROR | \
	UDMA_INTR_RX_TIMEOUT | \
	UDMA_INTR_RX_ABORT | \
	UDMA_INTR_RX_DONE)

#define UDMA_TX_INTERRUPTS ( \
	UDMA_INTR_TX_ABORT | \
	UDMA_INTR_TX_DONE)

#define UDMA_IS_RX_INTERRUPT(status) ((status) & UDMA_RX_INTERRUPTS)
#define UDMA_IS_TX_INTERRUPT(status) ((status) & UDMA_TX_INTERRUPTS)


/* Current devices have 8 sets of RX buffer registers */
#define UDMA_RX_BUFS_COUNT	8
#define UDMA_RX_BUFS_REG_OFFSET (UDMA_RX_BUF1_PTR_LO - UDMA_RX_BUF0_PTR_LO)
#define UDMA_RX_BUFx_PTR_LO(x)	(UDMA_RX_BUF0_PTR_LO + \
				 ((x) * UDMA_RX_BUFS_REG_OFFSET))
#define UDMA_RX_BUFx_PTR_HI(x)	(UDMA_RX_BUF0_PTR_HI + \
				 ((x) * UDMA_RX_BUFS_REG_OFFSET))
#define UDMA_RX_BUFx_STATUS(x)	(UDMA_RX_BUF0_STATUS + \
				 ((x) * UDMA_RX_BUFS_REG_OFFSET))
#define UDMA_RX_BUFx_DATA_LEN(x) (UDMA_RX_BUF0_DATA_LEN + \
				  ((x) * UDMA_RX_BUFS_REG_OFFSET))

/* Current devices have 2 sets of TX buffer registers */
#define UDMA_TX_BUFS_COUNT	2
#define UDMA_TX_BUFS_REG_OFFSET (UDMA_TX_BUF1_PTR_LO - UDMA_TX_BUF0_PTR_LO)
#define UDMA_TX_BUFx_PTR_LO(x)	(UDMA_TX_BUF0_PTR_LO + \
				 ((x) * UDMA_TX_BUFS_REG_OFFSET))
#define UDMA_TX_BUFx_PTR_HI(x)	(UDMA_TX_BUF0_PTR_HI + \
				 ((x) * UDMA_TX_BUFS_REG_OFFSET))
#define UDMA_TX_BUFx_STATUS(x)	(UDMA_TX_BUF0_STATUS + \
				 ((x) * UDMA_TX_BUFS_REG_OFFSET))
#define UDMA_TX_BUFx_DATA_LEN(x) (UDMA_TX_BUF0_DATA_LEN + \
				  ((x) * UDMA_TX_BUFS_REG_OFFSET))
#define UDMA_TX_BUFx_DATA_SENT(x) (UDMA_TX_BUF0_DATA_SENT + \
				   ((x) * UDMA_TX_BUFS_REG_OFFSET))
#define REGS_8250 0
#define REGS_DMA_RX 1
#define REGS_DMA_TX 2
#define REGS_DMA_ISR 3
#define REGS_DMA_ARB 4
#define REGS_MAX 5

#define TX_BUF_SIZE 4096
#define RX_BUF_SIZE 4096
#define RX_BUFS_COUNT 2
#define KHZ    1000
#define MHZ(x) ((x) * KHZ * KHZ)

static const u32 brcmstb_rate_table[] = {
	MHZ(81),
	MHZ(108),
	MHZ(64),		/* Actually 64285715 for some chips */
	MHZ(48),
};

static const u32 brcmstb_rate_table_7278[] = {
	MHZ(81),
	MHZ(108),
	0,
	MHZ(48),
};

struct brcmuart_priv {
	int		line;
	struct clk	*baud_mux_clk;
	unsigned long	default_mux_rate;
	u32		real_rates[ARRAY_SIZE(brcmstb_rate_table)];
	const u32	*rate_table;
	ktime_t		char_wait;
	struct uart_port *up;
	struct hrtimer	hrt;
	bool		shutdown;
	bool		dma_enabled;
	struct uart_8250_dma dma;
	void __iomem	*regs[REGS_MAX];
	dma_addr_t	rx_addr;
	void		*rx_bufs;
	size_t		rx_size;
	int		rx_next_buf;
	dma_addr_t	tx_addr;
	void		*tx_buf;
	size_t		tx_size;
	bool		tx_running;
	bool		rx_running;
	struct dentry	*debugfs_dir;

	/* stats exposed through debugfs */
	u64		dma_rx_partial_buf;
	u64		dma_rx_full_buf;
	u32		rx_bad_timeout_late_char;
	u32		rx_bad_timeout_no_char;
	u32		rx_missing_close_timeout;
	u32		rx_err;
	u32		rx_timeout;
	u32		rx_abort;
	u32		saved_mctrl;
};

static struct dentry *brcmuart_debugfs_root;

/*
 * Register access routines
 */
static u32 udma_readl(struct brcmuart_priv *priv,
		int reg_type, int offset)
{
	return readl(priv->regs[reg_type] + offset);
}

static void udma_writel(struct brcmuart_priv *priv,
			int reg_type, int offset, u32 value)
{
	writel(value, priv->regs[reg_type] + offset);
}

static void udma_set(struct brcmuart_priv *priv,
		int reg_type, int offset, u32 bits)
{
	void __iomem *reg = priv->regs[reg_type] + offset;
	u32 value;

	value = readl(reg);
	value |= bits;
	writel(value, reg);
}

static void udma_unset(struct brcmuart_priv *priv,
		int reg_type, int offset, u32 bits)
{
	void __iomem *reg = priv->regs[reg_type] + offset;
	u32 value;

	value = readl(reg);
	value &= ~bits;
	writel(value, reg);
}

/*
 * The UART DMA engine hardware can be used by multiple UARTS, but
 * only one at a time. Sharing is not currently supported so
 * the first UART to request the DMA engine will get it and any
 * subsequent requests by other UARTS will fail.
 */
static int brcmuart_arbitration(struct brcmuart_priv *priv, bool acquire)
{
	u32 rx_grant;
	u32 tx_grant;
	int waits;
	int ret = 0;

	if (acquire) {
		udma_set(priv, REGS_DMA_ARB, UDMA_ARB_RX, UDMA_ARB_REQ);
		udma_set(priv, REGS_DMA_ARB, UDMA_ARB_TX, UDMA_ARB_REQ);

		waits = 1;
		while (1) {
			rx_grant = udma_readl(priv, REGS_DMA_ARB, UDMA_ARB_RX);
			tx_grant = udma_readl(priv, REGS_DMA_ARB, UDMA_ARB_TX);
			if (rx_grant & tx_grant & UDMA_ARB_GRANT)
				return 0;
			if (waits-- == 0)
				break;
			msleep(1);
		}
		ret = 1;
	}

	udma_unset(priv, REGS_DMA_ARB, UDMA_ARB_RX, UDMA_ARB_REQ);
	udma_unset(priv, REGS_DMA_ARB, UDMA_ARB_TX, UDMA_ARB_REQ);
	return ret;
}

static void brcmuart_init_dma_hardware(struct brcmuart_priv *priv)
{
	u32 daddr;
	u32 value;
	int x;

	/* Start with all interrupts disabled */
	udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_SET, 0xffffffff);

	udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFFER_SIZE, RX_BUF_SIZE);

	/*
	 * Setup buffer close to happen when 32 character times have
	 * elapsed since the last character was received.
	 */
	udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFFER_CLOSE, 16*10*32);
	value = (RX_BUFS_COUNT << UDMA_RX_CTRL_NUM_BUF_USED_SHIFT)
		| UDMA_RX_CTRL_BUF_CLOSE_MODE
		| UDMA_RX_CTRL_BUF_CLOSE_ENA;
	udma_writel(priv, REGS_DMA_RX, UDMA_RX_CTRL, value);

	udma_writel(priv, REGS_DMA_RX, UDMA_RX_BLOCKOUT_COUNTER, 0);
	daddr = priv->rx_addr;
	for (x = 0; x < RX_BUFS_COUNT; x++) {

		/* Set RX transfer length to 0 for unknown */
		udma_writel(priv, REGS_DMA_RX, UDMA_RX_TRANSFER_LEN, 0);

		udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFx_PTR_LO(x),
			    lower_32_bits(daddr));
		udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFx_PTR_HI(x),
			    upper_32_bits(daddr));
		daddr += RX_BUF_SIZE;
	}

	daddr = priv->tx_addr;
	udma_writel(priv, REGS_DMA_TX, UDMA_TX_BUFx_PTR_LO(0),
		    lower_32_bits(daddr));
	udma_writel(priv, REGS_DMA_TX, UDMA_TX_BUFx_PTR_HI(0),
		    upper_32_bits(daddr));
	udma_writel(priv, REGS_DMA_TX, UDMA_TX_CTRL,
		    UDMA_TX_CTRL_NUM_BUF_USED_1);

	/* clear all interrupts then enable them */
	udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_CLEAR, 0xffffffff);
	udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_CLEAR,
		UDMA_RX_INTERRUPTS | UDMA_TX_INTERRUPTS);

}

static void start_rx_dma(struct uart_8250_port *p)
{
	struct brcmuart_priv *priv = p->port.private_data;
	int x;

	udma_unset(priv, REGS_DMA_RX, UDMA_RX_CTRL, UDMA_RX_CTRL_ENA);

	/* Clear the RX ready bit for all buffers */
	for (x = 0; x < RX_BUFS_COUNT; x++)
		udma_unset(priv, REGS_DMA_RX, UDMA_RX_BUFx_STATUS(x),
			UDMA_RX_BUFX_STATUS_DATA_RDY);

	/* always start with buffer 0 */
	udma_unset(priv, REGS_DMA_RX, UDMA_RX_STATUS,
		   UDMA_RX_STATUS_ACTIVE_BUF_MASK);
	priv->rx_next_buf = 0;

	udma_set(priv, REGS_DMA_RX, UDMA_RX_CTRL, UDMA_RX_CTRL_ENA);
	priv->rx_running = true;
}

static void stop_rx_dma(struct uart_8250_port *p)
{
	struct brcmuart_priv *priv = p->port.private_data;

	/* If RX is running, set the RX ABORT */
	if (priv->rx_running)
		udma_set(priv, REGS_DMA_RX, UDMA_RX_CTRL, UDMA_RX_CTRL_ABORT);
}

static int stop_tx_dma(struct uart_8250_port *p)
{
	struct brcmuart_priv *priv = p->port.private_data;
	u32 value;

	/* If TX is running, set the TX ABORT */
	value = udma_readl(priv, REGS_DMA_TX, UDMA_TX_CTRL);
	if (value & UDMA_TX_CTRL_ENA)
		udma_set(priv, REGS_DMA_TX, UDMA_TX_CTRL, UDMA_TX_CTRL_ABORT);
	priv->tx_running = false;
	return 0;
}

/*
 * NOTE: printk's in this routine will hang the system if this is
 * the console tty
 */
static int brcmuart_tx_dma(struct uart_8250_port *p)
{
	struct brcmuart_priv *priv = p->port.private_data;
	struct circ_buf *xmit = &p->port.state->xmit;
	u32 tx_size;

	if (uart_tx_stopped(&p->port) || priv->tx_running ||
		uart_circ_empty(xmit)) {
		return 0;
	}
	tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);

	priv->dma.tx_err = 0;
	memcpy(priv->tx_buf, &xmit->buf[xmit->tail], tx_size);
	xmit->tail += tx_size;
	xmit->tail &= UART_XMIT_SIZE - 1;
	p->port.icount.tx += tx_size;

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(&p->port);

	udma_writel(priv, REGS_DMA_TX, UDMA_TX_TRANSFER_LEN, tx_size);
	udma_writel(priv, REGS_DMA_TX, UDMA_TX_BUF0_DATA_LEN, tx_size);
	udma_unset(priv, REGS_DMA_TX, UDMA_TX_BUF0_STATUS, UDMA_TX_BUFX_EMPTY);
	udma_set(priv, REGS_DMA_TX, UDMA_TX_CTRL, UDMA_TX_CTRL_ENA);
	priv->tx_running = true;

	return 0;
}

static void brcmuart_rx_buf_done_isr(struct uart_port *up, int index)
{
	struct brcmuart_priv *priv = up->private_data;
	struct tty_port *tty_port = &up->state->port;
	u32 status;
	u32 length;
	u32 copied;

	/* Make sure we're still in sync with the hardware */
	status = udma_readl(priv, REGS_DMA_RX, UDMA_RX_BUFx_STATUS(index));
	length = udma_readl(priv, REGS_DMA_RX, UDMA_RX_BUFx_DATA_LEN(index));

	if ((status & UDMA_RX_BUFX_STATUS_DATA_RDY) == 0) {
		dev_err(up->dev, "RX done interrupt but DATA_RDY not found\n");
		return;
	}
	if (status & (UDMA_RX_BUFX_STATUS_OVERRUN_ERR |
		      UDMA_RX_BUFX_STATUS_FRAME_ERR |
		      UDMA_RX_BUFX_STATUS_PARITY_ERR)) {
		if (status & UDMA_RX_BUFX_STATUS_OVERRUN_ERR) {
			up->icount.overrun++;
			dev_warn(up->dev, "RX OVERRUN Error\n");
		}
		if (status & UDMA_RX_BUFX_STATUS_FRAME_ERR) {
			up->icount.frame++;
			dev_warn(up->dev, "RX FRAMING Error\n");
		}
		if (status & UDMA_RX_BUFX_STATUS_PARITY_ERR) {
			up->icount.parity++;
			dev_warn(up->dev, "RX PARITY Error\n");
		}
	}
	copied = (u32)tty_insert_flip_string(
		tty_port,
		priv->rx_bufs + (index * RX_BUF_SIZE),
		length);
	if (copied != length) {
		dev_warn(up->dev, "Flip buffer overrun of %d bytes\n",
			 length - copied);
		up->icount.overrun += length - copied;
	}
	up->icount.rx += length;
	if (status & UDMA_RX_BUFX_STATUS_CLOSE_EXPIRED)
		priv->dma_rx_partial_buf++;
	else if (length != RX_BUF_SIZE)
		/*
		 * This is a bug in the controller that doesn't cause
		 * any problems but will be fixed in the future.
		 */
		priv->rx_missing_close_timeout++;
	else
		priv->dma_rx_full_buf++;

	tty_flip_buffer_push(tty_port);
}

static void brcmuart_rx_isr(struct uart_port *up, u32 rx_isr)
{
	struct brcmuart_priv *priv = up->private_data;
	struct device *dev = up->dev;
	u32 rx_done_isr;
	u32 check_isr;

	rx_done_isr = (rx_isr & UDMA_INTR_RX_READY_MASK);
	while (rx_done_isr) {
		check_isr = UDMA_INTR_RX_READY_BUF0 << priv->rx_next_buf;
		if (check_isr & rx_done_isr) {
			brcmuart_rx_buf_done_isr(up, priv->rx_next_buf);
		} else {
			dev_err(dev,
				"RX buffer ready out of sequence, restarting RX DMA\n");
			start_rx_dma(up_to_u8250p(up));
			break;
		}
		if (rx_isr & UDMA_RX_ERR_INTERRUPTS) {
			if (rx_isr & UDMA_INTR_RX_ERROR)
				priv->rx_err++;
			if (rx_isr & UDMA_INTR_RX_TIMEOUT) {
				priv->rx_timeout++;
				dev_err(dev, "RX TIMEOUT Error\n");
			}
			if (rx_isr & UDMA_INTR_RX_ABORT)
				priv->rx_abort++;
			priv->rx_running = false;
		}
		/* If not ABORT, re-enable RX buffer */
		if (!(rx_isr & UDMA_INTR_RX_ABORT))
			udma_unset(priv, REGS_DMA_RX,
				   UDMA_RX_BUFx_STATUS(priv->rx_next_buf),
				   UDMA_RX_BUFX_STATUS_DATA_RDY);
		rx_done_isr &= ~check_isr;
		priv->rx_next_buf++;
		if (priv->rx_next_buf == RX_BUFS_COUNT)
			priv->rx_next_buf = 0;
	}
}

static void brcmuart_tx_isr(struct uart_port *up, u32 isr)
{
	struct brcmuart_priv *priv = up->private_data;
	struct device *dev = up->dev;
	struct uart_8250_port *port_8250 = up_to_u8250p(up);
	struct circ_buf	*xmit = &port_8250->port.state->xmit;

	if (isr & UDMA_INTR_TX_ABORT) {
		if (priv->tx_running)
			dev_err(dev, "Unexpected TX_ABORT interrupt\n");
		return;
	}
	priv->tx_running = false;
	if (!uart_circ_empty(xmit) && !uart_tx_stopped(up))
		brcmuart_tx_dma(port_8250);
}

static irqreturn_t brcmuart_isr(int irq, void *dev_id)
{
	struct uart_port *up = dev_id;
	struct device *dev = up->dev;
	struct brcmuart_priv *priv = up->private_data;
	unsigned long flags;
	u32 interrupts;
	u32 rval;
	u32 tval;

	interrupts = udma_readl(priv, REGS_DMA_ISR, UDMA_INTR_STATUS);
	if (interrupts == 0)
		return IRQ_NONE;

	spin_lock_irqsave(&up->lock, flags);

	/* Clear all interrupts */
	udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_CLEAR, interrupts);

	rval = UDMA_IS_RX_INTERRUPT(interrupts);
	if (rval)
		brcmuart_rx_isr(up, rval);
	tval = UDMA_IS_TX_INTERRUPT(interrupts);
	if (tval)
		brcmuart_tx_isr(up, tval);
	if ((rval | tval) == 0)
		dev_warn(dev, "Spurious interrupt: 0x%x\n", interrupts);

	spin_unlock_irqrestore(&up->lock, flags);
	return IRQ_HANDLED;
}

static int brcmuart_startup(struct uart_port *port)
{
	int res;
	struct uart_8250_port *up = up_to_u8250p(port);
	struct brcmuart_priv *priv = up->port.private_data;

	priv->shutdown = false;

	/*
	 * prevent serial8250_do_startup() from allocating non-existent
	 * DMA resources
	 */
	up->dma = NULL;

	res = serial8250_do_startup(port);
	if (!priv->dma_enabled)
		return res;
	/*
	 * Disable the Receive Data Interrupt because the DMA engine
	 * will handle this.
	 */
	up->ier &= ~UART_IER_RDI;
	serial_port_out(port, UART_IER, up->ier);

	priv->tx_running = false;
	priv->dma.rx_dma = NULL;
	priv->dma.tx_dma = brcmuart_tx_dma;
	up->dma = &priv->dma;

	brcmuart_init_dma_hardware(priv);
	start_rx_dma(up);
	return res;
}

static void brcmuart_shutdown(struct uart_port *port)
{
	struct uart_8250_port *up = up_to_u8250p(port);
	struct brcmuart_priv *priv = up->port.private_data;
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);
	priv->shutdown = true;
	if (priv->dma_enabled) {
		stop_rx_dma(up);
		stop_tx_dma(up);
		/* disable all interrupts */
		udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_SET,
			UDMA_RX_INTERRUPTS | UDMA_TX_INTERRUPTS);
	}

	/*
	 * prevent serial8250_do_shutdown() from trying to free
	 * DMA resources that we never alloc'd for this driver.
	 */
	up->dma = NULL;

	spin_unlock_irqrestore(&port->lock, flags);
	serial8250_do_shutdown(port);
}

/*
 * Not all clocks run at the exact specified rate, so set each requested
 * rate and then get the actual rate.
 */
static void init_real_clk_rates(struct device *dev, struct brcmuart_priv *priv)
{
	int x;
	int rc;

	priv->default_mux_rate = clk_get_rate(priv->baud_mux_clk);
	for (x = 0; x < ARRAY_SIZE(priv->real_rates); x++) {
		if (priv->rate_table[x] == 0) {
			priv->real_rates[x] = 0;
			continue;
		}
		rc = clk_set_rate(priv->baud_mux_clk, priv->rate_table[x]);
		if (rc) {
			dev_err(dev, "Error selecting BAUD MUX clock for %u\n",
				priv->rate_table[x]);
			priv->real_rates[x] = priv->rate_table[x];
		} else {
			priv->real_rates[x] = clk_get_rate(priv->baud_mux_clk);
		}
	}
	clk_set_rate(priv->baud_mux_clk, priv->default_mux_rate);
}

static void set_clock_mux(struct uart_port *up, struct brcmuart_priv *priv,
			u32 baud)
{
	u32 percent;
	u32 best_percent = UINT_MAX;
	u32 quot;
	u32 best_quot = 1;
	u32 rate;
	int best_index = -1;
	u64 hires_rate;
	u64 hires_baud;
	u64 hires_err;
	int rc;
	int i;
	int real_baud;

	/* If the Baud Mux Clock was not specified, just return */
	if (priv->baud_mux_clk == NULL)
		return;

	/* Find the closest match for specified baud */
	for (i = 0; i < ARRAY_SIZE(priv->real_rates); i++) {
		if (priv->real_rates[i] == 0)
			continue;
		rate = priv->real_rates[i] / 16;
		quot = DIV_ROUND_CLOSEST(rate, baud);
		if (!quot)
			continue;

		/* increase resolution to get xx.xx percent */
		hires_rate = (u64)rate * 10000;
		hires_baud = (u64)baud * 10000;

		hires_err = div_u64(hires_rate, (u64)quot);

		/* get the delta */
		if (hires_err > hires_baud)
			hires_err = (hires_err - hires_baud);
		else
			hires_err = (hires_baud - hires_err);

		percent = (unsigned long)DIV_ROUND_CLOSEST_ULL(hires_err, baud);
		dev_dbg(up->dev,
			"Baud rate: %u, MUX Clk: %u, Error: %u.%u%%\n",
			baud, priv->real_rates[i], percent / 100,
			percent % 100);
		if (percent < best_percent) {
			best_percent = percent;
			best_index = i;
			best_quot = quot;
		}
	}
	if (best_index == -1) {
		dev_err(up->dev, "Error, %d BAUD rate is too fast.\n", baud);
		return;
	}
	rate = priv->real_rates[best_index];
	rc = clk_set_rate(priv->baud_mux_clk, rate);
	if (rc)
		dev_err(up->dev, "Error selecting BAUD MUX clock\n");

	/* Error over 3 percent will cause data errors */
	if (best_percent > 300)
		dev_err(up->dev, "Error, baud: %d has %u.%u%% error\n",
			baud, percent / 100, percent % 100);

	real_baud = rate / 16 / best_quot;
	dev_dbg(up->dev, "Selecting BAUD MUX rate: %u\n", rate);
	dev_dbg(up->dev, "Requested baud: %u, Actual baud: %u\n",
		baud, real_baud);

	/* calc nanoseconds for 1.5 characters time at the given baud rate */
	i = NSEC_PER_SEC / real_baud / 10;
	i += (i / 2);
	priv->char_wait = ns_to_ktime(i);

	up->uartclk = rate;
}

static void brcmstb_set_termios(struct uart_port *up,
				struct ktermios *termios,
				const struct ktermios *old)
{
	struct uart_8250_port *p8250 = up_to_u8250p(up);
	struct brcmuart_priv *priv = up->private_data;

	if (priv->dma_enabled)
		stop_rx_dma(p8250);
	set_clock_mux(up, priv, tty_termios_baud_rate(termios));
	serial8250_do_set_termios(up, termios, old);
	if (p8250->mcr & UART_MCR_AFE)
		p8250->port.status |= UPSTAT_AUTOCTS;
	if (priv->dma_enabled)
		start_rx_dma(p8250);
}

static int brcmuart_handle_irq(struct uart_port *p)
{
	unsigned int iir = serial_port_in(p, UART_IIR);
	struct brcmuart_priv *priv = p->private_data;
	struct uart_8250_port *up = up_to_u8250p(p);
	unsigned int status;
	unsigned long flags;
	unsigned int ier;
	unsigned int mcr;
	int handled = 0;

	/*
	 * There's a bug in some 8250 cores where we get a timeout
	 * interrupt but there is no data ready.
	 */
	if (((iir & UART_IIR_ID) == UART_IIR_RX_TIMEOUT) && !(priv->shutdown)) {
		spin_lock_irqsave(&p->lock, flags);
		status = serial_port_in(p, UART_LSR);
		if ((status & UART_LSR_DR) == 0) {

			ier = serial_port_in(p, UART_IER);
			/*
			 * if Receive Data Interrupt is enabled and
			 * we're uing hardware flow control, deassert
			 * RTS and wait for any chars in the pipline to
			 * arrive and then check for DR again.
			 */
			if ((ier & UART_IER_RDI) && (up->mcr & UART_MCR_AFE)) {
				ier &= ~(UART_IER_RLSI | UART_IER_RDI);
				serial_port_out(p, UART_IER, ier);
				mcr = serial_port_in(p, UART_MCR);
				mcr &= ~UART_MCR_RTS;
				serial_port_out(p, UART_MCR, mcr);
				hrtimer_start(&priv->hrt, priv->char_wait,
					      HRTIMER_MODE_REL);
			} else {
				serial_port_in(p, UART_RX);
			}

			handled = 1;
		}
		spin_unlock_irqrestore(&p->lock, flags);
		if (handled)
			return 1;
	}
	return serial8250_handle_irq(p, iir);
}

static enum hrtimer_restart brcmuart_hrtimer_func(struct hrtimer *t)
{
	struct brcmuart_priv *priv = container_of(t, struct brcmuart_priv, hrt);
	struct uart_port *p = priv->up;
	struct uart_8250_port *up = up_to_u8250p(p);
	unsigned int status;
	unsigned long flags;

	if (priv->shutdown)
		return HRTIMER_NORESTART;

	spin_lock_irqsave(&p->lock, flags);
	status = serial_port_in(p, UART_LSR);

	/*
	 * If a character did not arrive after the timeout, clear the false
	 * receive timeout.
	 */
	if ((status & UART_LSR_DR) == 0) {
		serial_port_in(p, UART_RX);
		priv->rx_bad_timeout_no_char++;
	} else {
		priv->rx_bad_timeout_late_char++;
	}

	/* re-enable receive unless upper layer has disabled it */
	if ((up->ier & (UART_IER_RLSI | UART_IER_RDI)) ==
	    (UART_IER_RLSI | UART_IER_RDI)) {
		status = serial_port_in(p, UART_IER);
		status |= (UART_IER_RLSI | UART_IER_RDI);
		serial_port_out(p, UART_IER, status);
		status = serial_port_in(p, UART_MCR);
		status |= UART_MCR_RTS;
		serial_port_out(p, UART_MCR, status);
	}
	spin_unlock_irqrestore(&p->lock, flags);
	return HRTIMER_NORESTART;
}

static const struct of_device_id brcmuart_dt_ids[] = {
	{
		.compatible = "brcm,bcm7278-uart",
		.data = brcmstb_rate_table_7278,
	},
	{
		.compatible = "brcm,bcm7271-uart",
		.data = brcmstb_rate_table,
	},
	{},
};

MODULE_DEVICE_TABLE(of, brcmuart_dt_ids);

static void brcmuart_free_bufs(struct device *dev, struct brcmuart_priv *priv)
{
	if (priv->rx_bufs)
		dma_free_coherent(dev, priv->rx_size, priv->rx_bufs,
				  priv->rx_addr);
	if (priv->tx_buf)
		dma_free_coherent(dev, priv->tx_size, priv->tx_buf,
				  priv->tx_addr);
}

static void brcmuart_throttle(struct uart_port *port)
{
	struct brcmuart_priv *priv = port->private_data;

	udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_SET, UDMA_RX_INTERRUPTS);
}

static void brcmuart_unthrottle(struct uart_port *port)
{
	struct brcmuart_priv *priv = port->private_data;

	udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_CLEAR,
		    UDMA_RX_INTERRUPTS);
}

static int debugfs_stats_show(struct seq_file *s, void *unused)
{
	struct brcmuart_priv *priv = s->private;

	seq_printf(s, "rx_err:\t\t\t\t%u\n",
		   priv->rx_err);
	seq_printf(s, "rx_timeout:\t\t\t%u\n",
		   priv->rx_timeout);
	seq_printf(s, "rx_abort:\t\t\t%u\n",
		   priv->rx_abort);
	seq_printf(s, "rx_bad_timeout_late_char:\t%u\n",
		   priv->rx_bad_timeout_late_char);
	seq_printf(s, "rx_bad_timeout_no_char:\t\t%u\n",
		   priv->rx_bad_timeout_no_char);
	seq_printf(s, "rx_missing_close_timeout:\t%u\n",
		   priv->rx_missing_close_timeout);
	if (priv->dma_enabled) {
		seq_printf(s, "dma_rx_partial_buf:\t\t%llu\n",
			   priv->dma_rx_partial_buf);
		seq_printf(s, "dma_rx_full_buf:\t\t%llu\n",
			   priv->dma_rx_full_buf);
	}
	return 0;
}
DEFINE_SHOW_ATTRIBUTE(debugfs_stats);

static void brcmuart_init_debugfs(struct brcmuart_priv *priv,
				  const char *device)
{
	priv->debugfs_dir = debugfs_create_dir(device, brcmuart_debugfs_root);
	debugfs_create_file("stats", 0444, priv->debugfs_dir, priv,
			    &debugfs_stats_fops);
}


static int brcmuart_probe(struct platform_device *pdev)
{
	struct resource *regs;
	struct device_node *np = pdev->dev.of_node;
	const struct of_device_id *of_id = NULL;
	struct uart_8250_port *new_port;
	struct device *dev = &pdev->dev;
	struct brcmuart_priv *priv;
	struct clk *baud_mux_clk;
	struct uart_8250_port up;
	int irq;
	void __iomem *membase = NULL;
	resource_size_t mapbase = 0;
	u32 clk_rate = 0;
	int ret;
	int x;
	int dma_irq;
	static const char * const reg_names[REGS_MAX] = {
		"uart", "dma_rx", "dma_tx", "dma_intr2", "dma_arb"
	};

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;
	priv = devm_kzalloc(dev, sizeof(struct brcmuart_priv),
			GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	of_id = of_match_node(brcmuart_dt_ids, np);
	if (!of_id || !of_id->data)
		priv->rate_table = brcmstb_rate_table;
	else
		priv->rate_table = of_id->data;

	for (x = 0; x < REGS_MAX; x++) {
		regs = platform_get_resource_byname(pdev, IORESOURCE_MEM,
						reg_names[x]);
		if (!regs)
			break;
		priv->regs[x] =	devm_ioremap(dev, regs->start,
					     resource_size(regs));
		if (!priv->regs[x])
			return -ENOMEM;
		if (x == REGS_8250) {
			mapbase = regs->start;
			membase = priv->regs[x];
		}
	}

	/* We should have just the uart base registers or all the registers */
	if (x != 1 && x != REGS_MAX) {
		dev_warn(dev, "%s registers not specified\n", reg_names[x]);
		return -EINVAL;
	}

	/* if the DMA registers were specified, try to enable DMA */
	if (x > REGS_DMA_RX) {
		if (brcmuart_arbitration(priv, 1) == 0) {
			u32 txrev = 0;
			u32 rxrev = 0;

			txrev = udma_readl(priv, REGS_DMA_RX, UDMA_RX_REVISION);
			rxrev = udma_readl(priv, REGS_DMA_TX, UDMA_TX_REVISION);
			if ((txrev >= UDMA_TX_REVISION_REQUIRED) &&
				(rxrev >= UDMA_RX_REVISION_REQUIRED)) {

				/* Enable the use of the DMA hardware */
				priv->dma_enabled = true;
			} else {
				brcmuart_arbitration(priv, 0);
				dev_err(dev,
					"Unsupported DMA Hardware Revision\n");
			}
		} else {
			dev_err(dev,
				"Timeout arbitrating for UART DMA hardware\n");
		}
	}

	of_property_read_u32(np, "clock-frequency", &clk_rate);

	/* See if a Baud clock has been specified */
	baud_mux_clk = of_clk_get_by_name(np, "sw_baud");
	if (IS_ERR(baud_mux_clk)) {
		if (PTR_ERR(baud_mux_clk) == -EPROBE_DEFER)
			return -EPROBE_DEFER;
		dev_dbg(dev, "BAUD MUX clock not specified\n");
	} else {
		dev_dbg(dev, "BAUD MUX clock found\n");
		ret = clk_prepare_enable(baud_mux_clk);
		if (ret)
			return ret;
		priv->baud_mux_clk = baud_mux_clk;
		init_real_clk_rates(dev, priv);
		clk_rate = priv->default_mux_rate;
	}

	if (clk_rate == 0) {
		dev_err(dev, "clock-frequency or clk not defined\n");
		return -EINVAL;
	}

	dev_dbg(dev, "DMA is %senabled\n", priv->dma_enabled ? "" : "not ");

	memset(&up, 0, sizeof(up));
	up.port.type = PORT_16550A;
	up.port.uartclk = clk_rate;
	up.port.dev = dev;
	up.port.mapbase = mapbase;
	up.port.membase = membase;
	up.port.irq = irq;
	up.port.handle_irq = brcmuart_handle_irq;
	up.port.regshift = 2;
	up.port.iotype = of_device_is_big_endian(np) ?
		UPIO_MEM32BE : UPIO_MEM32;
	up.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF
		| UPF_FIXED_PORT | UPF_FIXED_TYPE;
	up.port.dev = dev;
	up.port.private_data = priv;
	up.capabilities = UART_CAP_FIFO | UART_CAP_AFE;
	up.port.fifosize = 32;

	/* Check for a fixed line number */
	ret = of_alias_get_id(np, "serial");
	if (ret >= 0)
		up.port.line = ret;

	/* setup HR timer */
	hrtimer_init(&priv->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
	priv->hrt.function = brcmuart_hrtimer_func;

	up.port.shutdown = brcmuart_shutdown;
	up.port.startup = brcmuart_startup;
	up.port.throttle = brcmuart_throttle;
	up.port.unthrottle = brcmuart_unthrottle;
	up.port.set_termios = brcmstb_set_termios;

	if (priv->dma_enabled) {
		priv->rx_size = RX_BUF_SIZE * RX_BUFS_COUNT;
		priv->rx_bufs = dma_alloc_coherent(dev,
						   priv->rx_size,
						   &priv->rx_addr, GFP_KERNEL);
		if (!priv->rx_bufs) {
			ret = -ENOMEM;
			goto err;
		}
		priv->tx_size = UART_XMIT_SIZE;
		priv->tx_buf = dma_alloc_coherent(dev,
						  priv->tx_size,
						  &priv->tx_addr, GFP_KERNEL);
		if (!priv->tx_buf) {
			ret = -ENOMEM;
			goto err;
		}
	}

	ret = serial8250_register_8250_port(&up);
	if (ret < 0) {
		dev_err(dev, "unable to register 8250 port\n");
		goto err;
	}
	priv->line = ret;
	new_port = serial8250_get_port(ret);
	priv->up = &new_port->port;
	if (priv->dma_enabled) {
		dma_irq = platform_get_irq_byname(pdev,  "dma");
		if (dma_irq < 0) {
			ret = dma_irq;
			dev_err(dev, "no IRQ resource info\n");
			goto err1;
		}
		ret = devm_request_irq(dev, dma_irq, brcmuart_isr,
				IRQF_SHARED, "uart DMA irq", &new_port->port);
		if (ret) {
			dev_err(dev, "unable to register IRQ handler\n");
			goto err1;
		}
	}
	platform_set_drvdata(pdev, priv);
	brcmuart_init_debugfs(priv, dev_name(&pdev->dev));
	return 0;

err1:
	serial8250_unregister_port(priv->line);
err:
	brcmuart_free_bufs(dev, priv);
	brcmuart_arbitration(priv, 0);
	return ret;
}

static int brcmuart_remove(struct platform_device *pdev)
{
	struct brcmuart_priv *priv = platform_get_drvdata(pdev);

	debugfs_remove_recursive(priv->debugfs_dir);
	hrtimer_cancel(&priv->hrt);
	serial8250_unregister_port(priv->line);
	brcmuart_free_bufs(&pdev->dev, priv);
	brcmuart_arbitration(priv, 0);
	return 0;
}

static int __maybe_unused brcmuart_suspend(struct device *dev)
{
	struct brcmuart_priv *priv = dev_get_drvdata(dev);
	struct uart_8250_port *up = serial8250_get_port(priv->line);
	struct uart_port *port = &up->port;
	unsigned long flags;

	/*
	 * This will prevent resume from enabling RTS before the
	 *  baud rate has been restored.
	 */
	spin_lock_irqsave(&port->lock, flags);
	priv->saved_mctrl = port->mctrl;
	port->mctrl &= ~TIOCM_RTS;
	spin_unlock_irqrestore(&port->lock, flags);

	serial8250_suspend_port(priv->line);
	clk_disable_unprepare(priv->baud_mux_clk);

	return 0;
}

static int __maybe_unused brcmuart_resume(struct device *dev)
{
	struct brcmuart_priv *priv = dev_get_drvdata(dev);
	struct uart_8250_port *up = serial8250_get_port(priv->line);
	struct uart_port *port = &up->port;
	unsigned long flags;
	int ret;

	ret = clk_prepare_enable(priv->baud_mux_clk);
	if (ret)
		dev_err(dev, "Error enabling BAUD MUX clock\n");

	/*
	 * The hardware goes back to it's default after suspend
	 * so get the "clk" back in sync.
	 */
	ret = clk_set_rate(priv->baud_mux_clk, priv->default_mux_rate);
	if (ret)
		dev_err(dev, "Error restoring default BAUD MUX clock\n");
	if (priv->dma_enabled) {
		if (brcmuart_arbitration(priv, 1)) {
			dev_err(dev, "Timeout arbitrating for DMA hardware on resume\n");
			return(-EBUSY);
		}
		brcmuart_init_dma_hardware(priv);
		start_rx_dma(serial8250_get_port(priv->line));
	}
	serial8250_resume_port(priv->line);

	if (priv->saved_mctrl & TIOCM_RTS) {
		/* Restore RTS */
		spin_lock_irqsave(&port->lock, flags);
		port->mctrl |= TIOCM_RTS;
		port->ops->set_mctrl(port, port->mctrl);
		spin_unlock_irqrestore(&port->lock, flags);
	}

	return 0;
}

static const struct dev_pm_ops brcmuart_dev_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(brcmuart_suspend, brcmuart_resume)
};

static struct platform_driver brcmuart_platform_driver = {
	.driver = {
		.name	= "bcm7271-uart",
		.pm		= &brcmuart_dev_pm_ops,
		.of_match_table = brcmuart_dt_ids,
	},
	.probe		= brcmuart_probe,
	.remove		= brcmuart_remove,
};

static int __init brcmuart_init(void)
{
	brcmuart_debugfs_root = debugfs_create_dir(
		brcmuart_platform_driver.driver.name, NULL);
	return platform_driver_register(&brcmuart_platform_driver);
}
module_init(brcmuart_init);

static void __exit brcmuart_deinit(void)
{
	platform_driver_unregister(&brcmuart_platform_driver);
	debugfs_remove_recursive(brcmuart_debugfs_root);
}
module_exit(brcmuart_deinit);

MODULE_AUTHOR("Al Cooper");
MODULE_DESCRIPTION("Broadcom NS16550A compatible serial port driver");
MODULE_LICENSE("GPL v2");