summaryrefslogtreecommitdiff
path: root/drivers/memory/tegra/tegra20-emc.c
blob: 25ba3c5e4ad6a69de298da1e658d822a6b3af631 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Tegra20 External Memory Controller driver
 *
 * Author: Dmitry Osipenko <digetx@gmail.com>
 */

#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/clk/tegra.h>
#include <linux/debugfs.h>
#include <linux/devfreq.h>
#include <linux/err.h>
#include <linux/interconnect-provider.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/types.h>

#include <soc/tegra/common.h>
#include <soc/tegra/fuse.h>

#include "../jedec_ddr.h"
#include "../of_memory.h"

#include "mc.h"

#define EMC_INTSTATUS				0x000
#define EMC_INTMASK				0x004
#define EMC_DBG					0x008
#define EMC_ADR_CFG_0				0x010
#define EMC_TIMING_CONTROL			0x028
#define EMC_RC					0x02c
#define EMC_RFC					0x030
#define EMC_RAS					0x034
#define EMC_RP					0x038
#define EMC_R2W					0x03c
#define EMC_W2R					0x040
#define EMC_R2P					0x044
#define EMC_W2P					0x048
#define EMC_RD_RCD				0x04c
#define EMC_WR_RCD				0x050
#define EMC_RRD					0x054
#define EMC_REXT				0x058
#define EMC_WDV					0x05c
#define EMC_QUSE				0x060
#define EMC_QRST				0x064
#define EMC_QSAFE				0x068
#define EMC_RDV					0x06c
#define EMC_REFRESH				0x070
#define EMC_BURST_REFRESH_NUM			0x074
#define EMC_PDEX2WR				0x078
#define EMC_PDEX2RD				0x07c
#define EMC_PCHG2PDEN				0x080
#define EMC_ACT2PDEN				0x084
#define EMC_AR2PDEN				0x088
#define EMC_RW2PDEN				0x08c
#define EMC_TXSR				0x090
#define EMC_TCKE				0x094
#define EMC_TFAW				0x098
#define EMC_TRPAB				0x09c
#define EMC_TCLKSTABLE				0x0a0
#define EMC_TCLKSTOP				0x0a4
#define EMC_TREFBW				0x0a8
#define EMC_QUSE_EXTRA				0x0ac
#define EMC_ODT_WRITE				0x0b0
#define EMC_ODT_READ				0x0b4
#define EMC_MRR					0x0ec
#define EMC_FBIO_CFG5				0x104
#define EMC_FBIO_CFG6				0x114
#define EMC_STAT_CONTROL			0x160
#define EMC_STAT_LLMC_CONTROL			0x178
#define EMC_STAT_PWR_CLOCK_LIMIT		0x198
#define EMC_STAT_PWR_CLOCKS			0x19c
#define EMC_STAT_PWR_COUNT			0x1a0
#define EMC_AUTO_CAL_INTERVAL			0x2a8
#define EMC_CFG_2				0x2b8
#define EMC_CFG_DIG_DLL				0x2bc
#define EMC_DLL_XFORM_DQS			0x2c0
#define EMC_DLL_XFORM_QUSE			0x2c4
#define EMC_ZCAL_REF_CNT			0x2e0
#define EMC_ZCAL_WAIT_CNT			0x2e4
#define EMC_CFG_CLKTRIM_0			0x2d0
#define EMC_CFG_CLKTRIM_1			0x2d4
#define EMC_CFG_CLKTRIM_2			0x2d8

#define EMC_CLKCHANGE_REQ_ENABLE		BIT(0)
#define EMC_CLKCHANGE_PD_ENABLE			BIT(1)
#define EMC_CLKCHANGE_SR_ENABLE			BIT(2)

#define EMC_TIMING_UPDATE			BIT(0)

#define EMC_REFRESH_OVERFLOW_INT		BIT(3)
#define EMC_CLKCHANGE_COMPLETE_INT		BIT(4)
#define EMC_MRR_DIVLD_INT			BIT(5)

#define EMC_DBG_READ_MUX_ASSEMBLY		BIT(0)
#define EMC_DBG_WRITE_MUX_ACTIVE		BIT(1)
#define EMC_DBG_FORCE_UPDATE			BIT(2)
#define EMC_DBG_READ_DQM_CTRL			BIT(9)
#define EMC_DBG_CFG_PRIORITY			BIT(24)

#define EMC_FBIO_CFG5_DRAM_WIDTH_X16		BIT(4)
#define EMC_FBIO_CFG5_DRAM_TYPE			GENMASK(1, 0)

#define EMC_MRR_DEV_SELECTN			GENMASK(31, 30)
#define EMC_MRR_MRR_MA				GENMASK(23, 16)
#define EMC_MRR_MRR_DATA			GENMASK(15, 0)

#define EMC_ADR_CFG_0_EMEM_NUMDEV		GENMASK(25, 24)

#define EMC_PWR_GATHER_CLEAR			(1 << 8)
#define EMC_PWR_GATHER_DISABLE			(2 << 8)
#define EMC_PWR_GATHER_ENABLE			(3 << 8)

enum emc_dram_type {
	DRAM_TYPE_RESERVED,
	DRAM_TYPE_DDR1,
	DRAM_TYPE_LPDDR2,
	DRAM_TYPE_DDR2,
};

static const u16 emc_timing_registers[] = {
	EMC_RC,
	EMC_RFC,
	EMC_RAS,
	EMC_RP,
	EMC_R2W,
	EMC_W2R,
	EMC_R2P,
	EMC_W2P,
	EMC_RD_RCD,
	EMC_WR_RCD,
	EMC_RRD,
	EMC_REXT,
	EMC_WDV,
	EMC_QUSE,
	EMC_QRST,
	EMC_QSAFE,
	EMC_RDV,
	EMC_REFRESH,
	EMC_BURST_REFRESH_NUM,
	EMC_PDEX2WR,
	EMC_PDEX2RD,
	EMC_PCHG2PDEN,
	EMC_ACT2PDEN,
	EMC_AR2PDEN,
	EMC_RW2PDEN,
	EMC_TXSR,
	EMC_TCKE,
	EMC_TFAW,
	EMC_TRPAB,
	EMC_TCLKSTABLE,
	EMC_TCLKSTOP,
	EMC_TREFBW,
	EMC_QUSE_EXTRA,
	EMC_FBIO_CFG6,
	EMC_ODT_WRITE,
	EMC_ODT_READ,
	EMC_FBIO_CFG5,
	EMC_CFG_DIG_DLL,
	EMC_DLL_XFORM_DQS,
	EMC_DLL_XFORM_QUSE,
	EMC_ZCAL_REF_CNT,
	EMC_ZCAL_WAIT_CNT,
	EMC_AUTO_CAL_INTERVAL,
	EMC_CFG_CLKTRIM_0,
	EMC_CFG_CLKTRIM_1,
	EMC_CFG_CLKTRIM_2,
};

struct emc_timing {
	unsigned long rate;
	u32 data[ARRAY_SIZE(emc_timing_registers)];
};

enum emc_rate_request_type {
	EMC_RATE_DEVFREQ,
	EMC_RATE_DEBUG,
	EMC_RATE_ICC,
	EMC_RATE_TYPE_MAX,
};

struct emc_rate_request {
	unsigned long min_rate;
	unsigned long max_rate;
};

struct tegra_emc {
	struct device *dev;
	struct tegra_mc *mc;
	struct icc_provider provider;
	struct notifier_block clk_nb;
	struct clk *clk;
	void __iomem *regs;
	unsigned int dram_bus_width;

	struct emc_timing *timings;
	unsigned int num_timings;

	struct {
		struct dentry *root;
		unsigned long min_rate;
		unsigned long max_rate;
	} debugfs;

	/*
	 * There are multiple sources in the EMC driver which could request
	 * a min/max clock rate, these rates are contained in this array.
	 */
	struct emc_rate_request requested_rate[EMC_RATE_TYPE_MAX];

	/* protect shared rate-change code path */
	struct mutex rate_lock;

	struct devfreq_simple_ondemand_data ondemand_data;

	/* memory chip identity information */
	union lpddr2_basic_config4 basic_conf4;
	unsigned int manufacturer_id;
	unsigned int revision_id1;
	unsigned int revision_id2;

	bool mrr_error;
};

static irqreturn_t tegra_emc_isr(int irq, void *data)
{
	struct tegra_emc *emc = data;
	u32 intmask = EMC_REFRESH_OVERFLOW_INT;
	u32 status;

	status = readl_relaxed(emc->regs + EMC_INTSTATUS) & intmask;
	if (!status)
		return IRQ_NONE;

	/* notify about HW problem */
	if (status & EMC_REFRESH_OVERFLOW_INT)
		dev_err_ratelimited(emc->dev,
				    "refresh request overflow timeout\n");

	/* clear interrupts */
	writel_relaxed(status, emc->regs + EMC_INTSTATUS);

	return IRQ_HANDLED;
}

static struct emc_timing *tegra_emc_find_timing(struct tegra_emc *emc,
						unsigned long rate)
{
	struct emc_timing *timing = NULL;
	unsigned int i;

	for (i = 0; i < emc->num_timings; i++) {
		if (emc->timings[i].rate >= rate) {
			timing = &emc->timings[i];
			break;
		}
	}

	if (!timing) {
		dev_err(emc->dev, "no timing for rate %lu\n", rate);
		return NULL;
	}

	return timing;
}

static int emc_prepare_timing_change(struct tegra_emc *emc, unsigned long rate)
{
	struct emc_timing *timing = tegra_emc_find_timing(emc, rate);
	unsigned int i;

	if (!timing)
		return -EINVAL;

	dev_dbg(emc->dev, "%s: using timing rate %lu for requested rate %lu\n",
		__func__, timing->rate, rate);

	/* program shadow registers */
	for (i = 0; i < ARRAY_SIZE(timing->data); i++)
		writel_relaxed(timing->data[i],
			       emc->regs + emc_timing_registers[i]);

	/* wait until programming has settled */
	readl_relaxed(emc->regs + emc_timing_registers[i - 1]);

	return 0;
}

static int emc_complete_timing_change(struct tegra_emc *emc, bool flush)
{
	int err;
	u32 v;

	dev_dbg(emc->dev, "%s: flush %d\n", __func__, flush);

	if (flush) {
		/* manually initiate memory timing update */
		writel_relaxed(EMC_TIMING_UPDATE,
			       emc->regs + EMC_TIMING_CONTROL);
		return 0;
	}

	err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_INTSTATUS, v,
						v & EMC_CLKCHANGE_COMPLETE_INT,
						1, 100);
	if (err) {
		dev_err(emc->dev, "emc-car handshake timeout: %d\n", err);
		return err;
	}

	return 0;
}

static int tegra_emc_clk_change_notify(struct notifier_block *nb,
				       unsigned long msg, void *data)
{
	struct tegra_emc *emc = container_of(nb, struct tegra_emc, clk_nb);
	struct clk_notifier_data *cnd = data;
	int err;

	switch (msg) {
	case PRE_RATE_CHANGE:
		err = emc_prepare_timing_change(emc, cnd->new_rate);
		break;

	case ABORT_RATE_CHANGE:
		err = emc_prepare_timing_change(emc, cnd->old_rate);
		if (err)
			break;

		err = emc_complete_timing_change(emc, true);
		break;

	case POST_RATE_CHANGE:
		err = emc_complete_timing_change(emc, false);
		break;

	default:
		return NOTIFY_DONE;
	}

	return notifier_from_errno(err);
}

static int load_one_timing_from_dt(struct tegra_emc *emc,
				   struct emc_timing *timing,
				   struct device_node *node)
{
	u32 rate;
	int err;

	if (!of_device_is_compatible(node, "nvidia,tegra20-emc-table")) {
		dev_err(emc->dev, "incompatible DT node: %pOF\n", node);
		return -EINVAL;
	}

	err = of_property_read_u32(node, "clock-frequency", &rate);
	if (err) {
		dev_err(emc->dev, "timing %pOF: failed to read rate: %d\n",
			node, err);
		return err;
	}

	err = of_property_read_u32_array(node, "nvidia,emc-registers",
					 timing->data,
					 ARRAY_SIZE(emc_timing_registers));
	if (err) {
		dev_err(emc->dev,
			"timing %pOF: failed to read emc timing data: %d\n",
			node, err);
		return err;
	}

	/*
	 * The EMC clock rate is twice the bus rate, and the bus rate is
	 * measured in kHz.
	 */
	timing->rate = rate * 2 * 1000;

	dev_dbg(emc->dev, "%s: %pOF: EMC rate %lu\n",
		__func__, node, timing->rate);

	return 0;
}

static int cmp_timings(const void *_a, const void *_b)
{
	const struct emc_timing *a = _a;
	const struct emc_timing *b = _b;

	if (a->rate < b->rate)
		return -1;

	if (a->rate > b->rate)
		return 1;

	return 0;
}

static int tegra_emc_load_timings_from_dt(struct tegra_emc *emc,
					  struct device_node *node)
{
	struct device_node *child;
	struct emc_timing *timing;
	int child_count;
	int err;

	child_count = of_get_child_count(node);
	if (!child_count) {
		dev_err(emc->dev, "no memory timings in DT node: %pOF\n", node);
		return -EINVAL;
	}

	emc->timings = devm_kcalloc(emc->dev, child_count, sizeof(*timing),
				    GFP_KERNEL);
	if (!emc->timings)
		return -ENOMEM;

	timing = emc->timings;

	for_each_child_of_node(node, child) {
		if (of_node_name_eq(child, "lpddr2"))
			continue;

		err = load_one_timing_from_dt(emc, timing++, child);
		if (err) {
			of_node_put(child);
			return err;
		}

		emc->num_timings++;
	}

	sort(emc->timings, emc->num_timings, sizeof(*timing), cmp_timings,
	     NULL);

	dev_info_once(emc->dev,
		      "got %u timings for RAM code %u (min %luMHz max %luMHz)\n",
		      emc->num_timings,
		      tegra_read_ram_code(),
		      emc->timings[0].rate / 1000000,
		      emc->timings[emc->num_timings - 1].rate / 1000000);

	return 0;
}

static struct device_node *
tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
{
	struct device *dev = emc->dev;
	struct device_node *np;
	u32 value, ram_code;
	int err;

	if (emc->mrr_error) {
		dev_warn(dev, "memory timings skipped due to MRR error\n");
		return NULL;
	}

	if (of_get_child_count(dev->of_node) == 0) {
		dev_info_once(dev, "device-tree doesn't have memory timings\n");
		return NULL;
	}

	if (!of_property_read_bool(dev->of_node, "nvidia,use-ram-code"))
		return of_node_get(dev->of_node);

	ram_code = tegra_read_ram_code();

	for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np;
	     np = of_find_node_by_name(np, "emc-tables")) {
		err = of_property_read_u32(np, "nvidia,ram-code", &value);
		if (err || value != ram_code) {
			struct device_node *lpddr2_np;
			bool cfg_mismatches = false;

			lpddr2_np = of_find_node_by_name(np, "lpddr2");
			if (lpddr2_np) {
				const struct lpddr2_info *info;

				info = of_lpddr2_get_info(lpddr2_np, dev);
				if (info) {
					if (info->manufacturer_id >= 0 &&
					    info->manufacturer_id != emc->manufacturer_id)
						cfg_mismatches = true;

					if (info->revision_id1 >= 0 &&
					    info->revision_id1 != emc->revision_id1)
						cfg_mismatches = true;

					if (info->revision_id2 >= 0 &&
					    info->revision_id2 != emc->revision_id2)
						cfg_mismatches = true;

					if (info->density != emc->basic_conf4.density)
						cfg_mismatches = true;

					if (info->io_width != emc->basic_conf4.io_width)
						cfg_mismatches = true;

					if (info->arch_type != emc->basic_conf4.arch_type)
						cfg_mismatches = true;
				} else {
					dev_err(dev, "failed to parse %pOF\n", lpddr2_np);
					cfg_mismatches = true;
				}

				of_node_put(lpddr2_np);
			} else {
				cfg_mismatches = true;
			}

			if (cfg_mismatches) {
				of_node_put(np);
				continue;
			}
		}

		return np;
	}

	dev_err(dev, "no memory timings for RAM code %u found in device tree\n",
		ram_code);

	return NULL;
}

static int emc_read_lpddr_mode_register(struct tegra_emc *emc,
					unsigned int emem_dev,
					unsigned int register_addr,
					unsigned int *register_data)
{
	u32 memory_dev = emem_dev ? 1 : 2;
	u32 val, mr_mask = 0xff;
	int err;

	/* clear data-valid interrupt status */
	writel_relaxed(EMC_MRR_DIVLD_INT, emc->regs + EMC_INTSTATUS);

	/* issue mode register read request */
	val  = FIELD_PREP(EMC_MRR_DEV_SELECTN, memory_dev);
	val |= FIELD_PREP(EMC_MRR_MRR_MA, register_addr);

	writel_relaxed(val, emc->regs + EMC_MRR);

	/* wait for the LPDDR2 data-valid interrupt */
	err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_INTSTATUS, val,
						val & EMC_MRR_DIVLD_INT,
						1, 100);
	if (err) {
		dev_err(emc->dev, "mode register %u read failed: %d\n",
			register_addr, err);
		emc->mrr_error = true;
		return err;
	}

	/* read out mode register data */
	val = readl_relaxed(emc->regs + EMC_MRR);
	*register_data = FIELD_GET(EMC_MRR_MRR_DATA, val) & mr_mask;

	return 0;
}

static void emc_read_lpddr_sdram_info(struct tegra_emc *emc,
				      unsigned int emem_dev,
				      bool print_out)
{
	/* these registers are standard for all LPDDR JEDEC memory chips */
	emc_read_lpddr_mode_register(emc, emem_dev, 5, &emc->manufacturer_id);
	emc_read_lpddr_mode_register(emc, emem_dev, 6, &emc->revision_id1);
	emc_read_lpddr_mode_register(emc, emem_dev, 7, &emc->revision_id2);
	emc_read_lpddr_mode_register(emc, emem_dev, 8, &emc->basic_conf4.value);

	if (!print_out)
		return;

	dev_info(emc->dev, "SDRAM[dev%u]: manufacturer: 0x%x (%s) rev1: 0x%x rev2: 0x%x prefetch: S%u density: %uMbit iowidth: %ubit\n",
		 emem_dev, emc->manufacturer_id,
		 lpddr2_jedec_manufacturer(emc->manufacturer_id),
		 emc->revision_id1, emc->revision_id2,
		 4 >> emc->basic_conf4.arch_type,
		 64 << emc->basic_conf4.density,
		 32 >> emc->basic_conf4.io_width);
}

static int emc_setup_hw(struct tegra_emc *emc)
{
	u32 emc_cfg, emc_dbg, emc_fbio, emc_adr_cfg;
	u32 intmask = EMC_REFRESH_OVERFLOW_INT;
	static bool print_sdram_info_once;
	enum emc_dram_type dram_type;
	const char *dram_type_str;
	unsigned int emem_numdev;

	emc_cfg = readl_relaxed(emc->regs + EMC_CFG_2);

	/*
	 * Depending on a memory type, DRAM should enter either self-refresh
	 * or power-down state on EMC clock change.
	 */
	if (!(emc_cfg & EMC_CLKCHANGE_PD_ENABLE) &&
	    !(emc_cfg & EMC_CLKCHANGE_SR_ENABLE)) {
		dev_err(emc->dev,
			"bootloader didn't specify DRAM auto-suspend mode\n");
		return -EINVAL;
	}

	/* enable EMC and CAR to handshake on PLL divider/source changes */
	emc_cfg |= EMC_CLKCHANGE_REQ_ENABLE;
	writel_relaxed(emc_cfg, emc->regs + EMC_CFG_2);

	/* initialize interrupt */
	writel_relaxed(intmask, emc->regs + EMC_INTMASK);
	writel_relaxed(intmask, emc->regs + EMC_INTSTATUS);

	/* ensure that unwanted debug features are disabled */
	emc_dbg = readl_relaxed(emc->regs + EMC_DBG);
	emc_dbg |= EMC_DBG_CFG_PRIORITY;
	emc_dbg &= ~EMC_DBG_READ_MUX_ASSEMBLY;
	emc_dbg &= ~EMC_DBG_WRITE_MUX_ACTIVE;
	emc_dbg &= ~EMC_DBG_FORCE_UPDATE;
	writel_relaxed(emc_dbg, emc->regs + EMC_DBG);

	emc_fbio = readl_relaxed(emc->regs + EMC_FBIO_CFG5);

	if (emc_fbio & EMC_FBIO_CFG5_DRAM_WIDTH_X16)
		emc->dram_bus_width = 16;
	else
		emc->dram_bus_width = 32;

	dram_type = FIELD_GET(EMC_FBIO_CFG5_DRAM_TYPE, emc_fbio);

	switch (dram_type) {
	case DRAM_TYPE_RESERVED:
		dram_type_str = "INVALID";
		break;
	case DRAM_TYPE_DDR1:
		dram_type_str = "DDR1";
		break;
	case DRAM_TYPE_LPDDR2:
		dram_type_str = "LPDDR2";
		break;
	case DRAM_TYPE_DDR2:
		dram_type_str = "DDR2";
		break;
	}

	emc_adr_cfg = readl_relaxed(emc->regs + EMC_ADR_CFG_0);
	emem_numdev = FIELD_GET(EMC_ADR_CFG_0_EMEM_NUMDEV, emc_adr_cfg) + 1;

	dev_info_once(emc->dev, "%ubit DRAM bus, %u %s %s attached\n",
		      emc->dram_bus_width, emem_numdev, dram_type_str,
		      emem_numdev == 2 ? "devices" : "device");

	if (dram_type == DRAM_TYPE_LPDDR2) {
		while (emem_numdev--)
			emc_read_lpddr_sdram_info(emc, emem_numdev,
						  !print_sdram_info_once);
		print_sdram_info_once = true;
	}

	return 0;
}

static long emc_round_rate(unsigned long rate,
			   unsigned long min_rate,
			   unsigned long max_rate,
			   void *arg)
{
	struct emc_timing *timing = NULL;
	struct tegra_emc *emc = arg;
	unsigned int i;

	if (!emc->num_timings)
		return clk_get_rate(emc->clk);

	min_rate = min(min_rate, emc->timings[emc->num_timings - 1].rate);

	for (i = 0; i < emc->num_timings; i++) {
		if (emc->timings[i].rate < rate && i != emc->num_timings - 1)
			continue;

		if (emc->timings[i].rate > max_rate) {
			i = max(i, 1u) - 1;

			if (emc->timings[i].rate < min_rate)
				break;
		}

		if (emc->timings[i].rate < min_rate)
			continue;

		timing = &emc->timings[i];
		break;
	}

	if (!timing) {
		dev_err(emc->dev, "no timing for rate %lu min %lu max %lu\n",
			rate, min_rate, max_rate);
		return -EINVAL;
	}

	return timing->rate;
}

static void tegra_emc_rate_requests_init(struct tegra_emc *emc)
{
	unsigned int i;

	for (i = 0; i < EMC_RATE_TYPE_MAX; i++) {
		emc->requested_rate[i].min_rate = 0;
		emc->requested_rate[i].max_rate = ULONG_MAX;
	}
}

static int emc_request_rate(struct tegra_emc *emc,
			    unsigned long new_min_rate,
			    unsigned long new_max_rate,
			    enum emc_rate_request_type type)
{
	struct emc_rate_request *req = emc->requested_rate;
	unsigned long min_rate = 0, max_rate = ULONG_MAX;
	unsigned int i;
	int err;

	/* select minimum and maximum rates among the requested rates */
	for (i = 0; i < EMC_RATE_TYPE_MAX; i++, req++) {
		if (i == type) {
			min_rate = max(new_min_rate, min_rate);
			max_rate = min(new_max_rate, max_rate);
		} else {
			min_rate = max(req->min_rate, min_rate);
			max_rate = min(req->max_rate, max_rate);
		}
	}

	if (min_rate > max_rate) {
		dev_err_ratelimited(emc->dev, "%s: type %u: out of range: %lu %lu\n",
				    __func__, type, min_rate, max_rate);
		return -ERANGE;
	}

	/*
	 * EMC rate-changes should go via OPP API because it manages voltage
	 * changes.
	 */
	err = dev_pm_opp_set_rate(emc->dev, min_rate);
	if (err)
		return err;

	emc->requested_rate[type].min_rate = new_min_rate;
	emc->requested_rate[type].max_rate = new_max_rate;

	return 0;
}

static int emc_set_min_rate(struct tegra_emc *emc, unsigned long rate,
			    enum emc_rate_request_type type)
{
	struct emc_rate_request *req = &emc->requested_rate[type];
	int ret;

	mutex_lock(&emc->rate_lock);
	ret = emc_request_rate(emc, rate, req->max_rate, type);
	mutex_unlock(&emc->rate_lock);

	return ret;
}

static int emc_set_max_rate(struct tegra_emc *emc, unsigned long rate,
			    enum emc_rate_request_type type)
{
	struct emc_rate_request *req = &emc->requested_rate[type];
	int ret;

	mutex_lock(&emc->rate_lock);
	ret = emc_request_rate(emc, req->min_rate, rate, type);
	mutex_unlock(&emc->rate_lock);

	return ret;
}

/*
 * debugfs interface
 *
 * The memory controller driver exposes some files in debugfs that can be used
 * to control the EMC frequency. The top-level directory can be found here:
 *
 *   /sys/kernel/debug/emc
 *
 * It contains the following files:
 *
 *   - available_rates: This file contains a list of valid, space-separated
 *     EMC frequencies.
 *
 *   - min_rate: Writing a value to this file sets the given frequency as the
 *       floor of the permitted range. If this is higher than the currently
 *       configured EMC frequency, this will cause the frequency to be
 *       increased so that it stays within the valid range.
 *
 *   - max_rate: Similarily to the min_rate file, writing a value to this file
 *       sets the given frequency as the ceiling of the permitted range. If
 *       the value is lower than the currently configured EMC frequency, this
 *       will cause the frequency to be decreased so that it stays within the
 *       valid range.
 */

static bool tegra_emc_validate_rate(struct tegra_emc *emc, unsigned long rate)
{
	unsigned int i;

	for (i = 0; i < emc->num_timings; i++)
		if (rate == emc->timings[i].rate)
			return true;

	return false;
}

static int tegra_emc_debug_available_rates_show(struct seq_file *s, void *data)
{
	struct tegra_emc *emc = s->private;
	const char *prefix = "";
	unsigned int i;

	for (i = 0; i < emc->num_timings; i++) {
		seq_printf(s, "%s%lu", prefix, emc->timings[i].rate);
		prefix = " ";
	}

	seq_puts(s, "\n");

	return 0;
}

static int tegra_emc_debug_available_rates_open(struct inode *inode,
						struct file *file)
{
	return single_open(file, tegra_emc_debug_available_rates_show,
			   inode->i_private);
}

static const struct file_operations tegra_emc_debug_available_rates_fops = {
	.open = tegra_emc_debug_available_rates_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int tegra_emc_debug_min_rate_get(void *data, u64 *rate)
{
	struct tegra_emc *emc = data;

	*rate = emc->debugfs.min_rate;

	return 0;
}

static int tegra_emc_debug_min_rate_set(void *data, u64 rate)
{
	struct tegra_emc *emc = data;
	int err;

	if (!tegra_emc_validate_rate(emc, rate))
		return -EINVAL;

	err = emc_set_min_rate(emc, rate, EMC_RATE_DEBUG);
	if (err < 0)
		return err;

	emc->debugfs.min_rate = rate;

	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
			tegra_emc_debug_min_rate_get,
			tegra_emc_debug_min_rate_set, "%llu\n");

static int tegra_emc_debug_max_rate_get(void *data, u64 *rate)
{
	struct tegra_emc *emc = data;

	*rate = emc->debugfs.max_rate;

	return 0;
}

static int tegra_emc_debug_max_rate_set(void *data, u64 rate)
{
	struct tegra_emc *emc = data;
	int err;

	if (!tegra_emc_validate_rate(emc, rate))
		return -EINVAL;

	err = emc_set_max_rate(emc, rate, EMC_RATE_DEBUG);
	if (err < 0)
		return err;

	emc->debugfs.max_rate = rate;

	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
			tegra_emc_debug_max_rate_get,
			tegra_emc_debug_max_rate_set, "%llu\n");

static void tegra_emc_debugfs_init(struct tegra_emc *emc)
{
	struct device *dev = emc->dev;
	unsigned int i;
	int err;

	emc->debugfs.min_rate = ULONG_MAX;
	emc->debugfs.max_rate = 0;

	for (i = 0; i < emc->num_timings; i++) {
		if (emc->timings[i].rate < emc->debugfs.min_rate)
			emc->debugfs.min_rate = emc->timings[i].rate;

		if (emc->timings[i].rate > emc->debugfs.max_rate)
			emc->debugfs.max_rate = emc->timings[i].rate;
	}

	if (!emc->num_timings) {
		emc->debugfs.min_rate = clk_get_rate(emc->clk);
		emc->debugfs.max_rate = emc->debugfs.min_rate;
	}

	err = clk_set_rate_range(emc->clk, emc->debugfs.min_rate,
				 emc->debugfs.max_rate);
	if (err < 0) {
		dev_err(dev, "failed to set rate range [%lu-%lu] for %pC\n",
			emc->debugfs.min_rate, emc->debugfs.max_rate,
			emc->clk);
	}

	emc->debugfs.root = debugfs_create_dir("emc", NULL);

	debugfs_create_file("available_rates", 0444, emc->debugfs.root,
			    emc, &tegra_emc_debug_available_rates_fops);
	debugfs_create_file("min_rate", 0644, emc->debugfs.root,
			    emc, &tegra_emc_debug_min_rate_fops);
	debugfs_create_file("max_rate", 0644, emc->debugfs.root,
			    emc, &tegra_emc_debug_max_rate_fops);
}

static inline struct tegra_emc *
to_tegra_emc_provider(struct icc_provider *provider)
{
	return container_of(provider, struct tegra_emc, provider);
}

static struct icc_node_data *
emc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data)
{
	struct icc_provider *provider = data;
	struct icc_node_data *ndata;
	struct icc_node *node;

	/* External Memory is the only possible ICC route */
	list_for_each_entry(node, &provider->nodes, node_list) {
		if (node->id != TEGRA_ICC_EMEM)
			continue;

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

		/*
		 * SRC and DST nodes should have matching TAG in order to have
		 * it set by default for a requested path.
		 */
		ndata->tag = TEGRA_MC_ICC_TAG_ISO;
		ndata->node = node;

		return ndata;
	}

	return ERR_PTR(-EPROBE_DEFER);
}

static int emc_icc_set(struct icc_node *src, struct icc_node *dst)
{
	struct tegra_emc *emc = to_tegra_emc_provider(dst->provider);
	unsigned long long peak_bw = icc_units_to_bps(dst->peak_bw);
	unsigned long long avg_bw = icc_units_to_bps(dst->avg_bw);
	unsigned long long rate = max(avg_bw, peak_bw);
	unsigned int dram_data_bus_width_bytes;
	int err;

	/*
	 * Tegra20 EMC runs on x2 clock rate of SDRAM bus because DDR data
	 * is sampled on both clock edges.  This means that EMC clock rate
	 * equals to the peak data-rate.
	 */
	dram_data_bus_width_bytes = emc->dram_bus_width / 8;
	do_div(rate, dram_data_bus_width_bytes);
	rate = min_t(u64, rate, U32_MAX);

	err = emc_set_min_rate(emc, rate, EMC_RATE_ICC);
	if (err)
		return err;

	return 0;
}

static int tegra_emc_interconnect_init(struct tegra_emc *emc)
{
	const struct tegra_mc_soc *soc;
	struct icc_node *node;
	int err;

	emc->mc = devm_tegra_memory_controller_get(emc->dev);
	if (IS_ERR(emc->mc))
		return PTR_ERR(emc->mc);

	soc = emc->mc->soc;

	emc->provider.dev = emc->dev;
	emc->provider.set = emc_icc_set;
	emc->provider.data = &emc->provider;
	emc->provider.aggregate = soc->icc_ops->aggregate;
	emc->provider.xlate_extended = emc_of_icc_xlate_extended;

	err = icc_provider_add(&emc->provider);
	if (err)
		goto err_msg;

	/* create External Memory Controller node */
	node = icc_node_create(TEGRA_ICC_EMC);
	if (IS_ERR(node)) {
		err = PTR_ERR(node);
		goto del_provider;
	}

	node->name = "External Memory Controller";
	icc_node_add(node, &emc->provider);

	/* link External Memory Controller to External Memory (DRAM) */
	err = icc_link_create(node, TEGRA_ICC_EMEM);
	if (err)
		goto remove_nodes;

	/* create External Memory node */
	node = icc_node_create(TEGRA_ICC_EMEM);
	if (IS_ERR(node)) {
		err = PTR_ERR(node);
		goto remove_nodes;
	}

	node->name = "External Memory (DRAM)";
	icc_node_add(node, &emc->provider);

	return 0;

remove_nodes:
	icc_nodes_remove(&emc->provider);
del_provider:
	icc_provider_del(&emc->provider);
err_msg:
	dev_err(emc->dev, "failed to initialize ICC: %d\n", err);

	return err;
}

static void devm_tegra_emc_unset_callback(void *data)
{
	tegra20_clk_set_emc_round_callback(NULL, NULL);
}

static void devm_tegra_emc_unreg_clk_notifier(void *data)
{
	struct tegra_emc *emc = data;

	clk_notifier_unregister(emc->clk, &emc->clk_nb);
}

static int tegra_emc_init_clk(struct tegra_emc *emc)
{
	int err;

	tegra20_clk_set_emc_round_callback(emc_round_rate, emc);

	err = devm_add_action_or_reset(emc->dev, devm_tegra_emc_unset_callback,
				       NULL);
	if (err)
		return err;

	emc->clk = devm_clk_get(emc->dev, NULL);
	if (IS_ERR(emc->clk)) {
		dev_err(emc->dev, "failed to get EMC clock: %pe\n", emc->clk);
		return PTR_ERR(emc->clk);
	}

	err = clk_notifier_register(emc->clk, &emc->clk_nb);
	if (err) {
		dev_err(emc->dev, "failed to register clk notifier: %d\n", err);
		return err;
	}

	err = devm_add_action_or_reset(emc->dev,
				       devm_tegra_emc_unreg_clk_notifier, emc);
	if (err)
		return err;

	return 0;
}

static int tegra_emc_devfreq_target(struct device *dev, unsigned long *freq,
				    u32 flags)
{
	struct tegra_emc *emc = dev_get_drvdata(dev);
	struct dev_pm_opp *opp;
	unsigned long rate;

	opp = devfreq_recommended_opp(dev, freq, flags);
	if (IS_ERR(opp)) {
		dev_err(dev, "failed to find opp for %lu Hz\n", *freq);
		return PTR_ERR(opp);
	}

	rate = dev_pm_opp_get_freq(opp);
	dev_pm_opp_put(opp);

	return emc_set_min_rate(emc, rate, EMC_RATE_DEVFREQ);
}

static int tegra_emc_devfreq_get_dev_status(struct device *dev,
					    struct devfreq_dev_status *stat)
{
	struct tegra_emc *emc = dev_get_drvdata(dev);

	/* freeze counters */
	writel_relaxed(EMC_PWR_GATHER_DISABLE, emc->regs + EMC_STAT_CONTROL);

	/*
	 *  busy_time: number of clocks EMC request was accepted
	 * total_time: number of clocks PWR_GATHER control was set to ENABLE
	 */
	stat->busy_time = readl_relaxed(emc->regs + EMC_STAT_PWR_COUNT);
	stat->total_time = readl_relaxed(emc->regs + EMC_STAT_PWR_CLOCKS);
	stat->current_frequency = clk_get_rate(emc->clk);

	/* clear counters and restart */
	writel_relaxed(EMC_PWR_GATHER_CLEAR, emc->regs + EMC_STAT_CONTROL);
	writel_relaxed(EMC_PWR_GATHER_ENABLE, emc->regs + EMC_STAT_CONTROL);

	return 0;
}

static struct devfreq_dev_profile tegra_emc_devfreq_profile = {
	.polling_ms = 30,
	.target = tegra_emc_devfreq_target,
	.get_dev_status = tegra_emc_devfreq_get_dev_status,
};

static int tegra_emc_devfreq_init(struct tegra_emc *emc)
{
	struct devfreq *devfreq;

	/*
	 * PWR_COUNT is 1/2 of PWR_CLOCKS at max, and thus, the up-threshold
	 * should be less than 50.  Secondly, multiple active memory clients
	 * may cause over 20% of lost clock cycles due to stalls caused by
	 * competing memory accesses.  This means that threshold should be
	 * set to a less than 30 in order to have a properly working governor.
	 */
	emc->ondemand_data.upthreshold = 20;

	/*
	 * Reset statistic gathers state, select global bandwidth for the
	 * statistics collection mode and set clocks counter saturation
	 * limit to maximum.
	 */
	writel_relaxed(0x00000000, emc->regs + EMC_STAT_CONTROL);
	writel_relaxed(0x00000000, emc->regs + EMC_STAT_LLMC_CONTROL);
	writel_relaxed(0xffffffff, emc->regs + EMC_STAT_PWR_CLOCK_LIMIT);

	devfreq = devm_devfreq_add_device(emc->dev, &tegra_emc_devfreq_profile,
					  DEVFREQ_GOV_SIMPLE_ONDEMAND,
					  &emc->ondemand_data);
	if (IS_ERR(devfreq)) {
		dev_err(emc->dev, "failed to initialize devfreq: %pe", devfreq);
		return PTR_ERR(devfreq);
	}

	return 0;
}

static int tegra_emc_probe(struct platform_device *pdev)
{
	struct tegra_core_opp_params opp_params = {};
	struct device_node *np;
	struct tegra_emc *emc;
	int irq, err;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "please update your device tree\n");
		return irq;
	}

	emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
	if (!emc)
		return -ENOMEM;

	mutex_init(&emc->rate_lock);
	emc->clk_nb.notifier_call = tegra_emc_clk_change_notify;
	emc->dev = &pdev->dev;

	emc->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(emc->regs))
		return PTR_ERR(emc->regs);

	err = emc_setup_hw(emc);
	if (err)
		return err;

	np = tegra_emc_find_node_by_ram_code(emc);
	if (np) {
		err = tegra_emc_load_timings_from_dt(emc, np);
		of_node_put(np);
		if (err)
			return err;
	}

	err = devm_request_irq(&pdev->dev, irq, tegra_emc_isr, 0,
			       dev_name(&pdev->dev), emc);
	if (err) {
		dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
		return err;
	}

	err = tegra_emc_init_clk(emc);
	if (err)
		return err;

	opp_params.init_state = true;

	err = devm_tegra_core_dev_init_opp_table(&pdev->dev, &opp_params);
	if (err)
		return err;

	platform_set_drvdata(pdev, emc);
	tegra_emc_rate_requests_init(emc);
	tegra_emc_debugfs_init(emc);
	tegra_emc_interconnect_init(emc);
	tegra_emc_devfreq_init(emc);

	/*
	 * Don't allow the kernel module to be unloaded. Unloading adds some
	 * extra complexity which doesn't really worth the effort in a case of
	 * this driver.
	 */
	try_module_get(THIS_MODULE);

	return 0;
}

static const struct of_device_id tegra_emc_of_match[] = {
	{ .compatible = "nvidia,tegra20-emc", },
	{},
};
MODULE_DEVICE_TABLE(of, tegra_emc_of_match);

static struct platform_driver tegra_emc_driver = {
	.probe = tegra_emc_probe,
	.driver = {
		.name = "tegra20-emc",
		.of_match_table = tegra_emc_of_match,
		.suppress_bind_attrs = true,
		.sync_state = icc_sync_state,
	},
};
module_platform_driver(tegra_emc_driver);

MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
MODULE_DESCRIPTION("NVIDIA Tegra20 EMC driver");
MODULE_SOFTDEP("pre: governor_simpleondemand");
MODULE_LICENSE("GPL v2");