Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/drivers/clocksource/arm_arch_timer.c
 *
 *  Copyright (C) 2011 ARM Ltd.
 *  All Rights Reserved
 */

#define pr_fmt(fmt) 	"arch_timer: " fmt

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/cpu_pm.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/sched/clock.h>
#include <linux/sched_clock.h>
#include <linux/acpi.h>

#include <asm/arch_timer.h>
#include <asm/virt.h>

#include <clocksource/arm_arch_timer.h>

#define CNTTIDR		0x08
#define CNTTIDR_VIRT(n)	(BIT(1) << ((n) * 4))

#define CNTACR(n)	(0x40 + ((n) * 4))
#define CNTACR_RPCT	BIT(0)
#define CNTACR_RVCT	BIT(1)
#define CNTACR_RFRQ	BIT(2)
#define CNTACR_RVOFF	BIT(3)
#define CNTACR_RWVT	BIT(4)
#define CNTACR_RWPT	BIT(5)

#define CNTVCT_LO	0x08
#define CNTVCT_HI	0x0c
#define CNTFRQ		0x10
#define CNTP_TVAL	0x28
#define CNTP_CTL	0x2c
#define CNTV_TVAL	0x38
#define CNTV_CTL	0x3c

static unsigned arch_timers_present __initdata;

static void __iomem *arch_counter_base;

struct arch_timer {
	void __iomem *base;
	struct clock_event_device evt;
};

#define to_arch_timer(e) container_of(e, struct arch_timer, evt)

static u32 arch_timer_rate;
static int arch_timer_ppi[ARCH_TIMER_MAX_TIMER_PPI];

static struct clock_event_device __percpu *arch_timer_evt;

static enum arch_timer_ppi_nr arch_timer_uses_ppi = ARCH_TIMER_VIRT_PPI;
static bool arch_timer_c3stop;
static bool arch_timer_mem_use_virtual;
static bool arch_counter_suspend_stop;
static bool vdso_default = true;

static cpumask_t evtstrm_available = CPU_MASK_NONE;
static bool evtstrm_enable = IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM);

static int __init early_evtstrm_cfg(char *buf)
{
	return strtobool(buf, &evtstrm_enable);
}
early_param("clocksource.arm_arch_timer.evtstrm", early_evtstrm_cfg);

/*
 * Architected system timer support.
 */

static __always_inline
void arch_timer_reg_write(int access, enum arch_timer_reg reg, u32 val,
			  struct clock_event_device *clk)
{
	if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
		struct arch_timer *timer = to_arch_timer(clk);
		switch (reg) {
		case ARCH_TIMER_REG_CTRL:
			writel_relaxed(val, timer->base + CNTP_CTL);
			break;
		case ARCH_TIMER_REG_TVAL:
			writel_relaxed(val, timer->base + CNTP_TVAL);
			break;
		}
	} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
		struct arch_timer *timer = to_arch_timer(clk);
		switch (reg) {
		case ARCH_TIMER_REG_CTRL:
			writel_relaxed(val, timer->base + CNTV_CTL);
			break;
		case ARCH_TIMER_REG_TVAL:
			writel_relaxed(val, timer->base + CNTV_TVAL);
			break;
		}
	} else {
		arch_timer_reg_write_cp15(access, reg, val);
	}
}

static __always_inline
u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
			struct clock_event_device *clk)
{
	u32 val;

	if (access == ARCH_TIMER_MEM_PHYS_ACCESS) {
		struct arch_timer *timer = to_arch_timer(clk);
		switch (reg) {
		case ARCH_TIMER_REG_CTRL:
			val = readl_relaxed(timer->base + CNTP_CTL);
			break;
		case ARCH_TIMER_REG_TVAL:
			val = readl_relaxed(timer->base + CNTP_TVAL);
			break;
		}
	} else if (access == ARCH_TIMER_MEM_VIRT_ACCESS) {
		struct arch_timer *timer = to_arch_timer(clk);
		switch (reg) {
		case ARCH_TIMER_REG_CTRL:
			val = readl_relaxed(timer->base + CNTV_CTL);
			break;
		case ARCH_TIMER_REG_TVAL:
			val = readl_relaxed(timer->base + CNTV_TVAL);
			break;
		}
	} else {
		val = arch_timer_reg_read_cp15(access, reg);
	}

	return val;
}

static notrace u64 arch_counter_get_cntpct_stable(void)
{
	return __arch_counter_get_cntpct_stable();
}

static notrace u64 arch_counter_get_cntpct(void)
{
	return __arch_counter_get_cntpct();
}

static notrace u64 arch_counter_get_cntvct_stable(void)
{
	return __arch_counter_get_cntvct_stable();
}

static notrace u64 arch_counter_get_cntvct(void)
{
	return __arch_counter_get_cntvct();
}

/*
 * Default to cp15 based access because arm64 uses this function for
 * sched_clock() before DT is probed and the cp15 method is guaranteed
 * to exist on arm64. arm doesn't use this before DT is probed so even
 * if we don't have the cp15 accessors we won't have a problem.
 */
u64 (*arch_timer_read_counter)(void) = arch_counter_get_cntvct;
EXPORT_SYMBOL_GPL(arch_timer_read_counter);

static u64 arch_counter_read(struct clocksource *cs)
{
	return arch_timer_read_counter();
}

static u64 arch_counter_read_cc(const struct cyclecounter *cc)
{
	return arch_timer_read_counter();
}

static struct clocksource clocksource_counter = {
	.name	= "arch_sys_counter",
	.rating	= 400,
	.read	= arch_counter_read,
	.mask	= CLOCKSOURCE_MASK(56),
	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
};

static struct cyclecounter cyclecounter __ro_after_init = {
	.read	= arch_counter_read_cc,
	.mask	= CLOCKSOURCE_MASK(56),
};

struct ate_acpi_oem_info {
	char oem_id[ACPI_OEM_ID_SIZE + 1];
	char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
	u32 oem_revision;
};

#ifdef CONFIG_FSL_ERRATUM_A008585
/*
 * The number of retries is an arbitrary value well beyond the highest number
 * of iterations the loop has been observed to take.
 */
#define __fsl_a008585_read_reg(reg) ({			\
	u64 _old, _new;					\
	int _retries = 200;				\
							\
	do {						\
		_old = read_sysreg(reg);		\
		_new = read_sysreg(reg);		\
		_retries--;				\
	} while (unlikely(_old != _new) && _retries);	\
							\
	WARN_ON_ONCE(!_retries);			\
	_new;						\
})

static u32 notrace fsl_a008585_read_cntp_tval_el0(void)
{
	return __fsl_a008585_read_reg(cntp_tval_el0);
}

static u32 notrace fsl_a008585_read_cntv_tval_el0(void)
{
	return __fsl_a008585_read_reg(cntv_tval_el0);
}

static u64 notrace fsl_a008585_read_cntpct_el0(void)
{
	return __fsl_a008585_read_reg(cntpct_el0);
}

static u64 notrace fsl_a008585_read_cntvct_el0(void)
{
	return __fsl_a008585_read_reg(cntvct_el0);
}
#endif

#ifdef CONFIG_HISILICON_ERRATUM_161010101
/*
 * Verify whether the value of the second read is larger than the first by
 * less than 32 is the only way to confirm the value is correct, so clear the
 * lower 5 bits to check whether the difference is greater than 32 or not.
 * Theoretically the erratum should not occur more than twice in succession
 * when reading the system counter, but it is possible that some interrupts
 * may lead to more than twice read errors, triggering the warning, so setting
 * the number of retries far beyond the number of iterations the loop has been
 * observed to take.
 */
#define __hisi_161010101_read_reg(reg) ({				\
	u64 _old, _new;						\
	int _retries = 50;					\
								\
	do {							\
		_old = read_sysreg(reg);			\
		_new = read_sysreg(reg);			\
		_retries--;					\
	} while (unlikely((_new - _old) >> 5) && _retries);	\
								\
	WARN_ON_ONCE(!_retries);				\
	_new;							\
})

static u32 notrace hisi_161010101_read_cntp_tval_el0(void)
{
	return __hisi_161010101_read_reg(cntp_tval_el0);
}

static u32 notrace hisi_161010101_read_cntv_tval_el0(void)
{
	return __hisi_161010101_read_reg(cntv_tval_el0);
}

static u64 notrace hisi_161010101_read_cntpct_el0(void)
{
	return __hisi_161010101_read_reg(cntpct_el0);
}

static u64 notrace hisi_161010101_read_cntvct_el0(void)
{
	return __hisi_161010101_read_reg(cntvct_el0);
}

static struct ate_acpi_oem_info hisi_161010101_oem_info[] = {
	/*
	 * Note that trailing spaces are required to properly match
	 * the OEM table information.
	 */
	{
		.oem_id		= "HISI  ",
		.oem_table_id	= "HIP05   ",
		.oem_revision	= 0,
	},
	{
		.oem_id		= "HISI  ",
		.oem_table_id	= "HIP06   ",
		.oem_revision	= 0,
	},
	{
		.oem_id		= "HISI  ",
		.oem_table_id	= "HIP07   ",
		.oem_revision	= 0,
	},
	{ /* Sentinel indicating the end of the OEM array */ },
};
#endif

#ifdef CONFIG_ARM64_ERRATUM_858921
static u64 notrace arm64_858921_read_cntpct_el0(void)
{
	u64 old, new;

	old = read_sysreg(cntpct_el0);
	new = read_sysreg(cntpct_el0);
	return (((old ^ new) >> 32) & 1) ? old : new;
}

static u64 notrace arm64_858921_read_cntvct_el0(void)
{
	u64 old, new;

	old = read_sysreg(cntvct_el0);
	new = read_sysreg(cntvct_el0);
	return (((old ^ new) >> 32) & 1) ? old : new;
}
#endif

#ifdef CONFIG_SUN50I_ERRATUM_UNKNOWN1
/*
 * The low bits of the counter registers are indeterminate while bit 10 or
 * greater is rolling over. Since the counter value can jump both backward
 * (7ff -> 000 -> 800) and forward (7ff -> fff -> 800), ignore register values
 * with all ones or all zeros in the low bits. Bound the loop by the maximum
 * number of CPU cycles in 3 consecutive 24 MHz counter periods.
 */
#define __sun50i_a64_read_reg(reg) ({					\
	u64 _val;							\
	int _retries = 150;						\
									\
	do {								\
		_val = read_sysreg(reg);				\
		_retries--;						\
	} while (((_val + 1) & GENMASK(9, 0)) <= 1 && _retries);	\
									\
	WARN_ON_ONCE(!_retries);					\
	_val;								\
})

static u64 notrace sun50i_a64_read_cntpct_el0(void)
{
	return __sun50i_a64_read_reg(cntpct_el0);
}

static u64 notrace sun50i_a64_read_cntvct_el0(void)
{
	return __sun50i_a64_read_reg(cntvct_el0);
}

static u32 notrace sun50i_a64_read_cntp_tval_el0(void)
{
	return read_sysreg(cntp_cval_el0) - sun50i_a64_read_cntpct_el0();
}

static u32 notrace sun50i_a64_read_cntv_tval_el0(void)
{
	return read_sysreg(cntv_cval_el0) - sun50i_a64_read_cntvct_el0();
}
#endif

#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
DEFINE_PER_CPU(const struct arch_timer_erratum_workaround *, timer_unstable_counter_workaround);
EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround);

static atomic_t timer_unstable_counter_workaround_in_use = ATOMIC_INIT(0);

static void erratum_set_next_event_tval_generic(const int access, unsigned long evt,
						struct clock_event_device *clk)
{
	unsigned long ctrl;
	u64 cval;

	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
	ctrl |= ARCH_TIMER_CTRL_ENABLE;
	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;

	if (access == ARCH_TIMER_PHYS_ACCESS) {
		cval = evt + arch_counter_get_cntpct();
		write_sysreg(cval, cntp_cval_el0);
	} else {
		cval = evt + arch_counter_get_cntvct();
		write_sysreg(cval, cntv_cval_el0);
	}

	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
}

static __maybe_unused int erratum_set_next_event_tval_virt(unsigned long evt,
					    struct clock_event_device *clk)
{
	erratum_set_next_event_tval_generic(ARCH_TIMER_VIRT_ACCESS, evt, clk);
	return 0;
}

static __maybe_unused int erratum_set_next_event_tval_phys(unsigned long evt,
					    struct clock_event_device *clk)
{
	erratum_set_next_event_tval_generic(ARCH_TIMER_PHYS_ACCESS, evt, clk);
	return 0;
}

static const struct arch_timer_erratum_workaround ool_workarounds[] = {
#ifdef CONFIG_FSL_ERRATUM_A008585
	{
		.match_type = ate_match_dt,
		.id = "fsl,erratum-a008585",
		.desc = "Freescale erratum a005858",
		.read_cntp_tval_el0 = fsl_a008585_read_cntp_tval_el0,
		.read_cntv_tval_el0 = fsl_a008585_read_cntv_tval_el0,
		.read_cntpct_el0 = fsl_a008585_read_cntpct_el0,
		.read_cntvct_el0 = fsl_a008585_read_cntvct_el0,
		.set_next_event_phys = erratum_set_next_event_tval_phys,
		.set_next_event_virt = erratum_set_next_event_tval_virt,
	},
#endif
#ifdef CONFIG_HISILICON_ERRATUM_161010101
	{
		.match_type = ate_match_dt,
		.id = "hisilicon,erratum-161010101",
		.desc = "HiSilicon erratum 161010101",
		.read_cntp_tval_el0 = hisi_161010101_read_cntp_tval_el0,
		.read_cntv_tval_el0 = hisi_161010101_read_cntv_tval_el0,
		.read_cntpct_el0 = hisi_161010101_read_cntpct_el0,
		.read_cntvct_el0 = hisi_161010101_read_cntvct_el0,
		.set_next_event_phys = erratum_set_next_event_tval_phys,
		.set_next_event_virt = erratum_set_next_event_tval_virt,
	},
	{
		.match_type = ate_match_acpi_oem_info,
		.id = hisi_161010101_oem_info,
		.desc = "HiSilicon erratum 161010101",
		.read_cntp_tval_el0 = hisi_161010101_read_cntp_tval_el0,
		.read_cntv_tval_el0 = hisi_161010101_read_cntv_tval_el0,
		.read_cntpct_el0 = hisi_161010101_read_cntpct_el0,
		.read_cntvct_el0 = hisi_161010101_read_cntvct_el0,
		.set_next_event_phys = erratum_set_next_event_tval_phys,
		.set_next_event_virt = erratum_set_next_event_tval_virt,
	},
#endif
#ifdef CONFIG_ARM64_ERRATUM_858921
	{
		.match_type = ate_match_local_cap_id,
		.id = (void *)ARM64_WORKAROUND_858921,
		.desc = "ARM erratum 858921",
		.read_cntpct_el0 = arm64_858921_read_cntpct_el0,
		.read_cntvct_el0 = arm64_858921_read_cntvct_el0,
	},
#endif
#ifdef CONFIG_SUN50I_ERRATUM_UNKNOWN1
	{
		.match_type = ate_match_dt,
		.id = "allwinner,erratum-unknown1",
		.desc = "Allwinner erratum UNKNOWN1",
		.read_cntp_tval_el0 = sun50i_a64_read_cntp_tval_el0,
		.read_cntv_tval_el0 = sun50i_a64_read_cntv_tval_el0,
		.read_cntpct_el0 = sun50i_a64_read_cntpct_el0,
		.read_cntvct_el0 = sun50i_a64_read_cntvct_el0,
		.set_next_event_phys = erratum_set_next_event_tval_phys,
		.set_next_event_virt = erratum_set_next_event_tval_virt,
	},
#endif
};

typedef bool (*ate_match_fn_t)(const struct arch_timer_erratum_workaround *,
			       const void *);

static
bool arch_timer_check_dt_erratum(const struct arch_timer_erratum_workaround *wa,
				 const void *arg)
{
	const struct device_node *np = arg;

	return of_property_read_bool(np, wa->id);
}

static
bool arch_timer_check_local_cap_erratum(const struct arch_timer_erratum_workaround *wa,
					const void *arg)
{
	return this_cpu_has_cap((uintptr_t)wa->id);
}


static
bool arch_timer_check_acpi_oem_erratum(const struct arch_timer_erratum_workaround *wa,
				       const void *arg)
{
	static const struct ate_acpi_oem_info empty_oem_info = {};
	const struct ate_acpi_oem_info *info = wa->id;
	const struct acpi_table_header *table = arg;

	/* Iterate over the ACPI OEM info array, looking for a match */
	while (memcmp(info, &empty_oem_info, sizeof(*info))) {
		if (!memcmp(info->oem_id, table->oem_id, ACPI_OEM_ID_SIZE) &&
		    !memcmp(info->oem_table_id, table->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
		    info->oem_revision == table->oem_revision)
			return true;

		info++;
	}

	return false;
}

static const struct arch_timer_erratum_workaround *
arch_timer_iterate_errata(enum arch_timer_erratum_match_type type,
			  ate_match_fn_t match_fn,
			  void *arg)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(ool_workarounds); i++) {
		if (ool_workarounds[i].match_type != type)
			continue;

		if (match_fn(&ool_workarounds[i], arg))
			return &ool_workarounds[i];
	}

	return NULL;
}

static
void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa,
				  bool local)
{
	int i;

	if (local) {
		__this_cpu_write(timer_unstable_counter_workaround, wa);
	} else {
		for_each_possible_cpu(i)
			per_cpu(timer_unstable_counter_workaround, i) = wa;
	}

	if (wa->read_cntvct_el0 || wa->read_cntpct_el0)
		atomic_set(&timer_unstable_counter_workaround_in_use, 1);

	/*
	 * Don't use the vdso fastpath if errata require using the
	 * out-of-line counter accessor. We may change our mind pretty
	 * late in the game (with a per-CPU erratum, for example), so
	 * change both the default value and the vdso itself.
	 */
	if (wa->read_cntvct_el0) {
		clocksource_counter.archdata.vdso_direct = false;
		vdso_default = false;
	}
}

static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type type,
					    void *arg)
{
	const struct arch_timer_erratum_workaround *wa, *__wa;
	ate_match_fn_t match_fn = NULL;
	bool local = false;

	switch (type) {
	case ate_match_dt:
		match_fn = arch_timer_check_dt_erratum;
		break;
	case ate_match_local_cap_id:
		match_fn = arch_timer_check_local_cap_erratum;
		local = true;
		break;
	case ate_match_acpi_oem_info:
		match_fn = arch_timer_check_acpi_oem_erratum;
		break;
	default:
		WARN_ON(1);
		return;
	}

	wa = arch_timer_iterate_errata(type, match_fn, arg);
	if (!wa)
		return;

	__wa = __this_cpu_read(timer_unstable_counter_workaround);
	if (__wa && wa != __wa)
		pr_warn("Can't enable workaround for %s (clashes with %s\n)",
			wa->desc, __wa->desc);

	if (__wa)
		return;

	arch_timer_enable_workaround(wa, local);
	pr_info("Enabling %s workaround for %s\n",
		local ? "local" : "global", wa->desc);
}

static bool arch_timer_this_cpu_has_cntvct_wa(void)
{
	return has_erratum_handler(read_cntvct_el0);
}

static bool arch_timer_counter_has_wa(void)
{
	return atomic_read(&timer_unstable_counter_workaround_in_use);
}
#else
#define arch_timer_check_ool_workaround(t,a)		do { } while(0)
#define arch_timer_this_cpu_has_cntvct_wa()		({false;})
#define arch_timer_counter_has_wa()			({false;})
#endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */

static __always_inline irqreturn_t timer_handler(const int access,
					struct clock_event_device *evt)
{
	unsigned long ctrl;

	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, evt);
	if (ctrl & ARCH_TIMER_CTRL_IT_STAT) {
		ctrl |= ARCH_TIMER_CTRL_IT_MASK;
		arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, evt);
		evt->event_handler(evt);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static irqreturn_t arch_timer_handler_virt(int irq, void *dev_id)
{
	struct clock_event_device *evt = dev_id;

	return timer_handler(ARCH_TIMER_VIRT_ACCESS, evt);
}

static irqreturn_t arch_timer_handler_phys(int irq, void *dev_id)
{
	struct clock_event_device *evt = dev_id;

	return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt);
}

static irqreturn_t arch_timer_handler_phys_mem(int irq, void *dev_id)
{
	struct clock_event_device *evt = dev_id;

	return timer_handler(ARCH_TIMER_MEM_PHYS_ACCESS, evt);
}

static irqreturn_t arch_timer_handler_virt_mem(int irq, void *dev_id)
{
	struct clock_event_device *evt = dev_id;

	return timer_handler(ARCH_TIMER_MEM_VIRT_ACCESS, evt);
}

static __always_inline int timer_shutdown(const int access,
					  struct clock_event_device *clk)
{
	unsigned long ctrl;

	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
	ctrl &= ~ARCH_TIMER_CTRL_ENABLE;
	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);

	return 0;
}

static int arch_timer_shutdown_virt(struct clock_event_device *clk)
{
	return timer_shutdown(ARCH_TIMER_VIRT_ACCESS, clk);
}

static int arch_timer_shutdown_phys(struct clock_event_device *clk)
{
	return timer_shutdown(ARCH_TIMER_PHYS_ACCESS, clk);
}

static int arch_timer_shutdown_virt_mem(struct clock_event_device *clk)
{
	return timer_shutdown(ARCH_TIMER_MEM_VIRT_ACCESS, clk);
}

static int arch_timer_shutdown_phys_mem(struct clock_event_device *clk)
{
	return timer_shutdown(ARCH_TIMER_MEM_PHYS_ACCESS, clk);
}

static __always_inline void set_next_event(const int access, unsigned long evt,
					   struct clock_event_device *clk)
{
	unsigned long ctrl;
	ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL, clk);
	ctrl |= ARCH_TIMER_CTRL_ENABLE;
	ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
	arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt, clk);
	arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl, clk);
}

static int arch_timer_set_next_event_virt(unsigned long evt,
					  struct clock_event_device *clk)
{
	set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
	return 0;
}

static int arch_timer_set_next_event_phys(unsigned long evt,
					  struct clock_event_device *clk)
{
	set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
	return 0;
}

static int arch_timer_set_next_event_virt_mem(unsigned long evt,
					      struct clock_event_device *clk)
{
	set_next_event(ARCH_TIMER_MEM_VIRT_ACCESS, evt, clk);
	return 0;
}

static int arch_timer_set_next_event_phys_mem(unsigned long evt,
					      struct clock_event_device *clk)
{
	set_next_event(ARCH_TIMER_MEM_PHYS_ACCESS, evt, clk);
	return 0;
}

static void __arch_timer_setup(unsigned type,
			       struct clock_event_device *clk)
{
	clk->features = CLOCK_EVT_FEAT_ONESHOT;

	if (type == ARCH_TIMER_TYPE_CP15) {
		typeof(clk->set_next_event) sne;

		arch_timer_check_ool_workaround(ate_match_local_cap_id, NULL);

		if (arch_timer_c3stop)
			clk->features |= CLOCK_EVT_FEAT_C3STOP;
		clk->name = "arch_sys_timer";
		clk->rating = 450;
		clk->cpumask = cpumask_of(smp_processor_id());
		clk->irq = arch_timer_ppi[arch_timer_uses_ppi];
		switch (arch_timer_uses_ppi) {
		case ARCH_TIMER_VIRT_PPI:
			clk->set_state_shutdown = arch_timer_shutdown_virt;
			clk->set_state_oneshot_stopped = arch_timer_shutdown_virt;
			sne = erratum_handler(set_next_event_virt);
			break;
		case ARCH_TIMER_PHYS_SECURE_PPI:
		case ARCH_TIMER_PHYS_NONSECURE_PPI:
		case ARCH_TIMER_HYP_PPI:
			clk->set_state_shutdown = arch_timer_shutdown_phys;
			clk->set_state_oneshot_stopped = arch_timer_shutdown_phys;
			sne = erratum_handler(set_next_event_phys);
			break;
		default:
			BUG();
		}

		clk->set_next_event = sne;
	} else {
		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
		clk->name = "arch_mem_timer";
		clk->rating = 400;
		clk->cpumask = cpu_possible_mask;
		if (arch_timer_mem_use_virtual) {
			clk->set_state_shutdown = arch_timer_shutdown_virt_mem;
			clk->set_state_oneshot_stopped = arch_timer_shutdown_virt_mem;
			clk->set_next_event =
				arch_timer_set_next_event_virt_mem;
		} else {
			clk->set_state_shutdown = arch_timer_shutdown_phys_mem;
			clk->set_state_oneshot_stopped = arch_timer_shutdown_phys_mem;
			clk->set_next_event =
				arch_timer_set_next_event_phys_mem;
		}
	}

	clk->set_state_shutdown(clk);

	clockevents_config_and_register(clk, arch_timer_rate, 0xf, 0x7fffffff);
}

static void arch_timer_evtstrm_enable(int divider)
{
	u32 cntkctl = arch_timer_get_cntkctl();

	cntkctl &= ~ARCH_TIMER_EVT_TRIGGER_MASK;
	/* Set the divider and enable virtual event stream */
	cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT)
			| ARCH_TIMER_VIRT_EVT_EN;
	arch_timer_set_cntkctl(cntkctl);
	arch_timer_set_evtstrm_feature();
	cpumask_set_cpu(smp_processor_id(), &evtstrm_available);
}

static void arch_timer_configure_evtstream(void)
{
	int evt_stream_div, pos;

	/* Find the closest power of two to the divisor */
	evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ;
	pos = fls(evt_stream_div);
	if (pos > 1 && !(evt_stream_div & (1 << (pos - 2))))
		pos--;
	/* enable event stream */
	arch_timer_evtstrm_enable(min(pos, 15));
}

static void arch_counter_set_user_access(void)
{
	u32 cntkctl = arch_timer_get_cntkctl();

	/* Disable user access to the timers and both counters */
	/* Also disable virtual event stream */
	cntkctl &= ~(ARCH_TIMER_USR_PT_ACCESS_EN
			| ARCH_TIMER_USR_VT_ACCESS_EN
		        | ARCH_TIMER_USR_VCT_ACCESS_EN
			| ARCH_TIMER_VIRT_EVT_EN
			| ARCH_TIMER_USR_PCT_ACCESS_EN);

	/*
	 * Enable user access to the virtual counter if it doesn't
	 * need to be workaround. The vdso may have been already
	 * disabled though.
	 */
	if (arch_timer_this_cpu_has_cntvct_wa())
		pr_info("CPU%d: Trapping CNTVCT access\n", smp_processor_id());
	else
		cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;

	arch_timer_set_cntkctl(cntkctl);
}

static bool arch_timer_has_nonsecure_ppi(void)
{
	return (arch_timer_uses_ppi == ARCH_TIMER_PHYS_SECURE_PPI &&
		arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);
}

static u32 check_ppi_trigger(int irq)
{
	u32 flags = irq_get_trigger_type(irq);

	if (flags != IRQF_TRIGGER_HIGH && flags != IRQF_TRIGGER_LOW) {
		pr_warn("WARNING: Invalid trigger for IRQ%d, assuming level low\n", irq);
		pr_warn("WARNING: Please fix your firmware\n");
		flags = IRQF_TRIGGER_LOW;
	}

	return flags;
}

static int arch_timer_starting_cpu(unsigned int cpu)
{
	struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt);
	u32 flags;

	__arch_timer_setup(ARCH_TIMER_TYPE_CP15, clk);

	flags = check_ppi_trigger(arch_timer_ppi[arch_timer_uses_ppi]);
	enable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], flags);

	if (arch_timer_has_nonsecure_ppi()) {
		flags = check_ppi_trigger(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);
		enable_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI],
				  flags);
	}

	arch_counter_set_user_access();
	if (evtstrm_enable)
		arch_timer_configure_evtstream();

	return 0;
}

/*
 * For historical reasons, when probing with DT we use whichever (non-zero)
 * rate was probed first, and don't verify that others match. If the first node
 * probed has a clock-frequency property, this overrides the HW register.
 */
static void arch_timer_of_configure_rate(u32 rate, struct device_node *np)
{
	/* Who has more than one independent system counter? */
	if (arch_timer_rate)
		return;

	if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
		arch_timer_rate = rate;

	/* Check the timer frequency. */
	if (arch_timer_rate == 0)
		pr_warn("frequency not available\n");
}

static void arch_timer_banner(unsigned type)
{
	pr_info("%s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n",
		type & ARCH_TIMER_TYPE_CP15 ? "cp15" : "",
		type == (ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM) ?
			" and " : "",
		type & ARCH_TIMER_TYPE_MEM ? "mmio" : "",
		(unsigned long)arch_timer_rate / 1000000,
		(unsigned long)(arch_timer_rate / 10000) % 100,
		type & ARCH_TIMER_TYPE_CP15 ?
			(arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI) ? "virt" : "phys" :
			"",
		type == (ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM) ? "/" : "",
		type & ARCH_TIMER_TYPE_MEM ?
			arch_timer_mem_use_virtual ? "virt" : "phys" :
			"");
}

u32 arch_timer_get_rate(void)
{
	return arch_timer_rate;
}

bool arch_timer_evtstrm_available(void)
{
	/*
	 * We might get called from a preemptible context. This is fine
	 * because availability of the event stream should be always the same
	 * for a preemptible context and context where we might resume a task.
	 */
	return cpumask_test_cpu(raw_smp_processor_id(), &evtstrm_available);
}

static u64 arch_counter_get_cntvct_mem(void)
{
	u32 vct_lo, vct_hi, tmp_hi;

	do {
		vct_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
		vct_lo = readl_relaxed(arch_counter_base + CNTVCT_LO);
		tmp_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
	} while (vct_hi != tmp_hi);

	return ((u64) vct_hi << 32) | vct_lo;
}

static struct arch_timer_kvm_info arch_timer_kvm_info;

struct arch_timer_kvm_info *arch_timer_get_kvm_info(void)
{
	return &arch_timer_kvm_info;
}

static void __init arch_counter_register(unsigned type)
{
	u64 start_count;

	/* Register the CP15 based counter if we have one */
	if (type & ARCH_TIMER_TYPE_CP15) {
		u64 (*rd)(void);

		if ((IS_ENABLED(CONFIG_ARM64) && !is_hyp_mode_available()) ||
		    arch_timer_uses_ppi == ARCH_TIMER_VIRT_PPI) {
			if (arch_timer_counter_has_wa())
				rd = arch_counter_get_cntvct_stable;
			else
				rd = arch_counter_get_cntvct;
		} else {
			if (arch_timer_counter_has_wa())
				rd = arch_counter_get_cntpct_stable;
			else
				rd = arch_counter_get_cntpct;
		}

		arch_timer_read_counter = rd;
		clocksource_counter.archdata.vdso_direct = vdso_default;
	} else {
		arch_timer_read_counter = arch_counter_get_cntvct_mem;
	}

	if (!arch_counter_suspend_stop)
		clocksource_counter.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP;
	start_count = arch_timer_read_counter();
	clocksource_register_hz(&clocksource_counter, arch_timer_rate);
	cyclecounter.mult = clocksource_counter.mult;
	cyclecounter.shift = clocksource_counter.shift;
	timecounter_init(&arch_timer_kvm_info.timecounter,
			 &cyclecounter, start_count);

	/* 56 bits minimum, so we assume worst case rollover */
	sched_clock_register(arch_timer_read_counter, 56, arch_timer_rate);
}

static void arch_timer_stop(struct clock_event_device *clk)
{
	pr_debug("disable IRQ%d cpu #%d\n", clk->irq, smp_processor_id());

	disable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi]);
	if (arch_timer_has_nonsecure_ppi())
		disable_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);

	clk->set_state_shutdown(clk);
}

static int arch_timer_dying_cpu(unsigned int cpu)
{
	struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt);

	cpumask_clear_cpu(smp_processor_id(), &evtstrm_available);

	arch_timer_stop(clk);
	return 0;
}

#ifdef CONFIG_CPU_PM
static DEFINE_PER_CPU(unsigned long, saved_cntkctl);
static int arch_timer_cpu_pm_notify(struct notifier_block *self,
				    unsigned long action, void *hcpu)
{
	if (action == CPU_PM_ENTER) {
		__this_cpu_write(saved_cntkctl, arch_timer_get_cntkctl());

		cpumask_clear_cpu(smp_processor_id(), &evtstrm_available);
	} else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT) {
		arch_timer_set_cntkctl(__this_cpu_read(saved_cntkctl));

		if (arch_timer_have_evtstrm_feature())
			cpumask_set_cpu(smp_processor_id(), &evtstrm_available);
	}
	return NOTIFY_OK;
}

static struct notifier_block arch_timer_cpu_pm_notifier = {
	.notifier_call = arch_timer_cpu_pm_notify,
};

static int __init arch_timer_cpu_pm_init(void)
{
	return cpu_pm_register_notifier(&arch_timer_cpu_pm_notifier);
}

static void __init arch_timer_cpu_pm_deinit(void)
{
	WARN_ON(cpu_pm_unregister_notifier(&arch_timer_cpu_pm_notifier));
}

#else
static int __init arch_timer_cpu_pm_init(void)
{
	return 0;
}

static void __init arch_timer_cpu_pm_deinit(void)
{
}
#endif

static int __init arch_timer_register(void)
{
	int err;
	int ppi;

	arch_timer_evt = alloc_percpu(struct clock_event_device);
	if (!arch_timer_evt) {
		err = -ENOMEM;
		goto out;
	}

	ppi = arch_timer_ppi[arch_timer_uses_ppi];
	switch (arch_timer_uses_ppi) {
	case ARCH_TIMER_VIRT_PPI:
		err = request_percpu_irq(ppi, arch_timer_handler_virt,
					 "arch_timer", arch_timer_evt);
		break;
	case ARCH_TIMER_PHYS_SECURE_PPI:
	case ARCH_TIMER_PHYS_NONSECURE_PPI:
		err = request_percpu_irq(ppi, arch_timer_handler_phys,
					 "arch_timer", arch_timer_evt);
		if (!err && arch_timer_has_nonsecure_ppi()) {
			ppi = arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI];
			err = request_percpu_irq(ppi, arch_timer_handler_phys,
						 "arch_timer", arch_timer_evt);
			if (err)
				free_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_SECURE_PPI],
						arch_timer_evt);
		}
		break;
	case ARCH_TIMER_HYP_PPI:
		err = request_percpu_irq(ppi, arch_timer_handler_phys,
					 "arch_timer", arch_timer_evt);
		break;
	default:
		BUG();
	}

	if (err) {
		pr_err("can't register interrupt %d (%d)\n", ppi, err);
		goto out_free;
	}

	err = arch_timer_cpu_pm_init();
	if (err)
		goto out_unreg_notify;

	/* Register and immediately configure the timer on the boot CPU */
	err = cpuhp_setup_state(CPUHP_AP_ARM_ARCH_TIMER_STARTING,
				"clockevents/arm/arch_timer:starting",
				arch_timer_starting_cpu, arch_timer_dying_cpu);
	if (err)
		goto out_unreg_cpupm;
	return 0;

out_unreg_cpupm:
	arch_timer_cpu_pm_deinit();

out_unreg_notify:
	free_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], arch_timer_evt);
	if (arch_timer_has_nonsecure_ppi())
		free_percpu_irq(arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI],
				arch_timer_evt);

out_free:
	free_percpu(arch_timer_evt);
out:
	return err;
}

static int __init arch_timer_mem_register(void __iomem *base, unsigned int irq)
{
	int ret;
	irq_handler_t func;
	struct arch_timer *t;

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

	t->base = base;
	t->evt.irq = irq;
	__arch_timer_setup(ARCH_TIMER_TYPE_MEM, &t->evt);

	if (arch_timer_mem_use_virtual)
		func = arch_timer_handler_virt_mem;
	else
		func = arch_timer_handler_phys_mem;

	ret = request_irq(irq, func, IRQF_TIMER, "arch_mem_timer", &t->evt);
	if (ret) {
		pr_err("Failed to request mem timer irq\n");
		kfree(t);
	}

	return ret;
}

static const struct of_device_id arch_timer_of_match[] __initconst = {
	{ .compatible   = "arm,armv7-timer",    },
	{ .compatible   = "arm,armv8-timer",    },
	{},
};

static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
	{ .compatible   = "arm,armv7-timer-mem", },
	{},
};

static bool __init arch_timer_needs_of_probing(void)
{
	struct device_node *dn;
	bool needs_probing = false;
	unsigned int mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM;

	/* We have two timers, and both device-tree nodes are probed. */
	if ((arch_timers_present & mask) == mask)
		return false;

	/*
	 * Only one type of timer is probed,
	 * check if we have another type of timer node in device-tree.
	 */
	if (arch_timers_present & ARCH_TIMER_TYPE_CP15)
		dn = of_find_matching_node(NULL, arch_timer_mem_of_match);
	else
		dn = of_find_matching_node(NULL, arch_timer_of_match);

	if (dn && of_device_is_available(dn))
		needs_probing = true;

	of_node_put(dn);

	return needs_probing;
}

static int __init arch_timer_common_init(void)
{
	arch_timer_banner(arch_timers_present);
	arch_counter_register(arch_timers_present);
	return arch_timer_arch_init();
}

/**
 * arch_timer_select_ppi() - Select suitable PPI for the current system.
 *
 * If HYP mode is available, we know that the physical timer
 * has been configured to be accessible from PL1. Use it, so
 * that a guest can use the virtual timer instead.
 *
 * On ARMv8.1 with VH extensions, the kernel runs in HYP. VHE
 * accesses to CNTP_*_EL1 registers are silently redirected to
 * their CNTHP_*_EL2 counterparts, and use a different PPI
 * number.
 *
 * If no interrupt provided for virtual timer, we'll have to
 * stick to the physical timer. It'd better be accessible...
 * For arm64 we never use the secure interrupt.
 *
 * Return: a suitable PPI type for the current system.
 */
static enum arch_timer_ppi_nr __init arch_timer_select_ppi(void)
{
	if (is_kernel_in_hyp_mode())
		return ARCH_TIMER_HYP_PPI;

	if (!is_hyp_mode_available() && arch_timer_ppi[ARCH_TIMER_VIRT_PPI])
		return ARCH_TIMER_VIRT_PPI;

	if (IS_ENABLED(CONFIG_ARM64))
		return ARCH_TIMER_PHYS_NONSECURE_PPI;

	return ARCH_TIMER_PHYS_SECURE_PPI;
}

static void __init arch_timer_populate_kvm_info(void)
{
	arch_timer_kvm_info.virtual_irq = arch_timer_ppi[ARCH_TIMER_VIRT_PPI];
	if (is_kernel_in_hyp_mode())
		arch_timer_kvm_info.physical_irq = arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI];
}

static int __init arch_timer_of_init(struct device_node *np)
{
	int i, ret;
	u32 rate;

	if (arch_timers_present & ARCH_TIMER_TYPE_CP15) {
		pr_warn("multiple nodes in dt, skipping\n");
		return 0;
	}

	arch_timers_present |= ARCH_TIMER_TYPE_CP15;
	for (i = ARCH_TIMER_PHYS_SECURE_PPI; i < ARCH_TIMER_MAX_TIMER_PPI; i++)
		arch_timer_ppi[i] = irq_of_parse_and_map(np, i);

	arch_timer_populate_kvm_info();

	rate = arch_timer_get_cntfrq();
	arch_timer_of_configure_rate(rate, np);

	arch_timer_c3stop = !of_property_read_bool(np, "always-on");

	/* Check for globally applicable workarounds */
	arch_timer_check_ool_workaround(ate_match_dt, np);

	/*
	 * If we cannot rely on firmware initializing the timer registers then
	 * we should use the physical timers instead.
	 */
	if (IS_ENABLED(CONFIG_ARM) &&
	    of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
		arch_timer_uses_ppi = ARCH_TIMER_PHYS_SECURE_PPI;
	else
		arch_timer_uses_ppi = arch_timer_select_ppi();

	if (!arch_timer_ppi[arch_timer_uses_ppi]) {
		pr_err("No interrupt available, giving up\n");
		return -EINVAL;
	}

	/* On some systems, the counter stops ticking when in suspend. */
	arch_counter_suspend_stop = of_property_read_bool(np,
							 "arm,no-tick-in-suspend");

	ret = arch_timer_register();
	if (ret)
		return ret;

	if (arch_timer_needs_of_probing())
		return 0;

	return arch_timer_common_init();
}
TIMER_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
TIMER_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);

static u32 __init
arch_timer_mem_frame_get_cntfrq(struct arch_timer_mem_frame *frame)
{
	void __iomem *base;
	u32 rate;

	base = ioremap(frame->cntbase, frame->size);
	if (!base) {
		pr_err("Unable to map frame @ %pa\n", &frame->cntbase);
		return 0;
	}

	rate = readl_relaxed(base + CNTFRQ);

	iounmap(base);

	return rate;
}

static struct arch_timer_mem_frame * __init
arch_timer_mem_find_best_frame(struct arch_timer_mem *timer_mem)
{
	struct arch_timer_mem_frame *frame, *best_frame = NULL;
	void __iomem *cntctlbase;
	u32 cnttidr;
	int i;

	cntctlbase = ioremap(timer_mem->cntctlbase, timer_mem->size);
	if (!cntctlbase) {
		pr_err("Can't map CNTCTLBase @ %pa\n",
			&timer_mem->cntctlbase);
		return NULL;
	}

	cnttidr = readl_relaxed(cntctlbase + CNTTIDR);

	/*
	 * Try to find a virtual capable frame. Otherwise fall back to a
	 * physical capable frame.
	 */
	for (i = 0; i < ARCH_TIMER_MEM_MAX_FRAMES; i++) {
		u32 cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT |
			     CNTACR_RWVT | CNTACR_RVOFF | CNTACR_RVCT;

		frame = &timer_mem->frame[i];
		if (!frame->valid)
			continue;

		/* Try enabling everything, and see what sticks */
		writel_relaxed(cntacr, cntctlbase + CNTACR(i));
		cntacr = readl_relaxed(cntctlbase + CNTACR(i));

		if ((cnttidr & CNTTIDR_VIRT(i)) &&
		    !(~cntacr & (CNTACR_RWVT | CNTACR_RVCT))) {
			best_frame = frame;
			arch_timer_mem_use_virtual = true;
			break;
		}

		if (~cntacr & (CNTACR_RWPT | CNTACR_RPCT))
			continue;

		best_frame = frame;
	}

	iounmap(cntctlbase);

	return best_frame;
}

static int __init
arch_timer_mem_frame_register(struct arch_timer_mem_frame *frame)
{
	void __iomem *base;
	int ret, irq = 0;

	if (arch_timer_mem_use_virtual)
		irq = frame->virt_irq;
	else
		irq = frame->phys_irq;

	if (!irq) {
		pr_err("Frame missing %s irq.\n",
		       arch_timer_mem_use_virtual ? "virt" : "phys");
		return -EINVAL;
	}

	if (!request_mem_region(frame->cntbase, frame->size,
				"arch_mem_timer"))
		return -EBUSY;

	base = ioremap(frame->cntbase, frame->size);
	if (!base) {
		pr_err("Can't map frame's registers\n");
		return -ENXIO;
	}

	ret = arch_timer_mem_register(base, irq);
	if (ret) {
		iounmap(base);
		return ret;
	}

	arch_counter_base = base;
	arch_timers_present |= ARCH_TIMER_TYPE_MEM;

	return 0;
}

static int __init arch_timer_mem_of_init(struct device_node *np)
{
	struct arch_timer_mem *timer_mem;
	struct arch_timer_mem_frame *frame;
	struct device_node *frame_node;
	struct resource res;
	int ret = -EINVAL;
	u32 rate;

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

	if (of_address_to_resource(np, 0, &res))
		goto out;
	timer_mem->cntctlbase = res.start;
	timer_mem->size = resource_size(&res);

	for_each_available_child_of_node(np, frame_node) {
		u32 n;
		struct arch_timer_mem_frame *frame;

		if (of_property_read_u32(frame_node, "frame-number", &n)) {
			pr_err(FW_BUG "Missing frame-number.\n");
			of_node_put(frame_node);
			goto out;
		}
		if (n >= ARCH_TIMER_MEM_MAX_FRAMES) {
			pr_err(FW_BUG "Wrong frame-number, only 0-%u are permitted.\n",
			       ARCH_TIMER_MEM_MAX_FRAMES - 1);
			of_node_put(frame_node);
			goto out;
		}
		frame = &timer_mem->frame[n];

		if (frame->valid) {
			pr_err(FW_BUG "Duplicated frame-number.\n");
			of_node_put(frame_node);
			goto out;
		}

		if (of_address_to_resource(frame_node, 0, &res)) {
			of_node_put(frame_node);
			goto out;
		}
		frame->cntbase = res.start;
		frame->size = resource_size(&res);

		frame->virt_irq = irq_of_parse_and_map(frame_node,
						       ARCH_TIMER_VIRT_SPI);
		frame->phys_irq = irq_of_parse_and_map(frame_node,
						       ARCH_TIMER_PHYS_SPI);

		frame->valid = true;
	}

	frame = arch_timer_mem_find_best_frame(timer_mem);
	if (!frame) {
		pr_err("Unable to find a suitable frame in timer @ %pa\n",
			&timer_mem->cntctlbase);
		ret = -EINVAL;
		goto out;
	}

	rate = arch_timer_mem_frame_get_cntfrq(frame);
	arch_timer_of_configure_rate(rate, np);

	ret = arch_timer_mem_frame_register(frame);
	if (!ret && !arch_timer_needs_of_probing())
		ret = arch_timer_common_init();
out:
	kfree(timer_mem);
	return ret;
}
TIMER_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
		       arch_timer_mem_of_init);

#ifdef CONFIG_ACPI_GTDT
static int __init
arch_timer_mem_verify_cntfrq(struct arch_timer_mem *timer_mem)
{
	struct arch_timer_mem_frame *frame;
	u32 rate;
	int i;

	for (i = 0; i < ARCH_TIMER_MEM_MAX_FRAMES; i++) {
		frame = &timer_mem->frame[i];

		if (!frame->valid)
			continue;

		rate = arch_timer_mem_frame_get_cntfrq(frame);
		if (rate == arch_timer_rate)
			continue;

		pr_err(FW_BUG "CNTFRQ mismatch: frame @ %pa: (0x%08lx), CPU: (0x%08lx)\n",
			&frame->cntbase,
			(unsigned long)rate, (unsigned long)arch_timer_rate);

		return -EINVAL;
	}

	return 0;
}

static int __init arch_timer_mem_acpi_init(int platform_timer_count)
{
	struct arch_timer_mem *timers, *timer;
	struct arch_timer_mem_frame *frame, *best_frame = NULL;
	int timer_count, i, ret = 0;

	timers = kcalloc(platform_timer_count, sizeof(*timers),
			    GFP_KERNEL);
	if (!timers)
		return -ENOMEM;

	ret = acpi_arch_timer_mem_init(timers, &timer_count);
	if (ret || !timer_count)
		goto out;

	/*
	 * While unlikely, it's theoretically possible that none of the frames
	 * in a timer expose the combination of feature we want.
	 */
	for (i = 0; i < timer_count; i++) {
		timer = &timers[i];

		frame = arch_timer_mem_find_best_frame(timer);
		if (!best_frame)
			best_frame = frame;

		ret = arch_timer_mem_verify_cntfrq(timer);
		if (ret) {
			pr_err("Disabling MMIO timers due to CNTFRQ mismatch\n");
			goto out;
		}

		if (!best_frame) /* implies !frame */
			/*
			 * Only complain about missing suitable frames if we
			 * haven't already found one in a previous iteration.
			 */
			pr_err("Unable to find a suitable frame in timer @ %pa\n",
				&timer->cntctlbase);
	}

	if (best_frame)
		ret = arch_timer_mem_frame_register(best_frame);
out:
	kfree(timers);
	return ret;
}

/* Initialize per-processor generic timer and memory-mapped timer(if present) */
static int __init arch_timer_acpi_init(struct acpi_table_header *table)
{
	int ret, platform_timer_count;

	if (arch_timers_present & ARCH_TIMER_TYPE_CP15) {
		pr_warn("already initialized, skipping\n");
		return -EINVAL;
	}

	arch_timers_present |= ARCH_TIMER_TYPE_CP15;

	ret = acpi_gtdt_init(table, &platform_timer_count);
	if (ret) {
		pr_err("Failed to init GTDT table.\n");
		return ret;
	}

	arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI] =
		acpi_gtdt_map_ppi(ARCH_TIMER_PHYS_NONSECURE_PPI);

	arch_timer_ppi[ARCH_TIMER_VIRT_PPI] =
		acpi_gtdt_map_ppi(ARCH_TIMER_VIRT_PPI);

	arch_timer_ppi[ARCH_TIMER_HYP_PPI] =
		acpi_gtdt_map_ppi(ARCH_TIMER_HYP_PPI);

	arch_timer_populate_kvm_info();

	/*
	 * When probing via ACPI, we have no mechanism to override the sysreg
	 * CNTFRQ value. This *must* be correct.
	 */
	arch_timer_rate = arch_timer_get_cntfrq();
	if (!arch_timer_rate) {
		pr_err(FW_BUG "frequency not available.\n");
		return -EINVAL;
	}

	arch_timer_uses_ppi = arch_timer_select_ppi();
	if (!arch_timer_ppi[arch_timer_uses_ppi]) {
		pr_err("No interrupt available, giving up\n");
		return -EINVAL;
	}

	/* Always-on capability */
	arch_timer_c3stop = acpi_gtdt_c3stop(arch_timer_uses_ppi);

	/* Check for globally applicable workarounds */
	arch_timer_check_ool_workaround(ate_match_acpi_oem_info, table);

	ret = arch_timer_register();
	if (ret)
		return ret;

	if (platform_timer_count &&
	    arch_timer_mem_acpi_init(platform_timer_count))
		pr_err("Failed to initialize memory-mapped timer.\n");

	return arch_timer_common_init();
}
TIMER_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init);
#endif