summaryrefslogtreecommitdiff
path: root/arch/arm/kernel/perf_event_v6.c
blob: 6fc2d228db55c1c7a63c185a97b40aaa1b86c726 (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
/*
 * ARMv6 Performance counter handling code.
 *
 * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
 *
 * ARMv6 has 2 configurable performance counters and a single cycle counter.
 * They all share a single reset bit but can be written to zero so we can use
 * that for a reset.
 *
 * The counters can't be individually enabled or disabled so when we remove
 * one event and replace it with another we could get spurious counts from the
 * wrong event. However, we can take advantage of the fact that the
 * performance counters can export events to the event bus, and the event bus
 * itself can be monitored. This requires that we *don't* export the events to
 * the event bus. The procedure for disabling a configurable counter is:
 *	- change the counter to count the ETMEXTOUT[0] signal (0x20). This
 *	  effectively stops the counter from counting.
 *	- disable the counter's interrupt generation (each counter has it's
 *	  own interrupt enable bit).
 * Once stopped, the counter value can be written as 0 to reset.
 *
 * To enable a counter:
 *	- enable the counter's interrupt generation.
 *	- set the new event type.
 *
 * Note: the dedicated cycle counter only counts cycles and can't be
 * enabled/disabled independently of the others. When we want to disable the
 * cycle counter, we have to just disable the interrupt reporting and start
 * ignoring that counter. When re-enabling, we have to reset the value and
 * enable the interrupt.
 */

#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V6K)
enum armv6_perf_types {
	ARMV6_PERFCTR_ICACHE_MISS	    = 0x0,
	ARMV6_PERFCTR_IBUF_STALL	    = 0x1,
	ARMV6_PERFCTR_DDEP_STALL	    = 0x2,
	ARMV6_PERFCTR_ITLB_MISS		    = 0x3,
	ARMV6_PERFCTR_DTLB_MISS		    = 0x4,
	ARMV6_PERFCTR_BR_EXEC		    = 0x5,
	ARMV6_PERFCTR_BR_MISPREDICT	    = 0x6,
	ARMV6_PERFCTR_INSTR_EXEC	    = 0x7,
	ARMV6_PERFCTR_DCACHE_HIT	    = 0x9,
	ARMV6_PERFCTR_DCACHE_ACCESS	    = 0xA,
	ARMV6_PERFCTR_DCACHE_MISS	    = 0xB,
	ARMV6_PERFCTR_DCACHE_WBACK	    = 0xC,
	ARMV6_PERFCTR_SW_PC_CHANGE	    = 0xD,
	ARMV6_PERFCTR_MAIN_TLB_MISS	    = 0xF,
	ARMV6_PERFCTR_EXPL_D_ACCESS	    = 0x10,
	ARMV6_PERFCTR_LSU_FULL_STALL	    = 0x11,
	ARMV6_PERFCTR_WBUF_DRAINED	    = 0x12,
	ARMV6_PERFCTR_CPU_CYCLES	    = 0xFF,
	ARMV6_PERFCTR_NOP		    = 0x20,
};

enum armv6_counters {
	ARMV6_CYCLE_COUNTER = 1,
	ARMV6_COUNTER0,
	ARMV6_COUNTER1,
};

/*
 * The hardware events that we support. We do support cache operations but
 * we have harvard caches and no way to combine instruction and data
 * accesses/misses in hardware.
 */
static const unsigned armv6_perf_map[PERF_COUNT_HW_MAX] = {
	[PERF_COUNT_HW_CPU_CYCLES]	    = ARMV6_PERFCTR_CPU_CYCLES,
	[PERF_COUNT_HW_INSTRUCTIONS]	    = ARMV6_PERFCTR_INSTR_EXEC,
	[PERF_COUNT_HW_CACHE_REFERENCES]    = HW_OP_UNSUPPORTED,
	[PERF_COUNT_HW_CACHE_MISSES]	    = HW_OP_UNSUPPORTED,
	[PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = ARMV6_PERFCTR_BR_EXEC,
	[PERF_COUNT_HW_BRANCH_MISSES]	    = ARMV6_PERFCTR_BR_MISPREDICT,
	[PERF_COUNT_HW_BUS_CYCLES]	    = HW_OP_UNSUPPORTED,
};

static const unsigned armv6_perf_cache_map[PERF_COUNT_HW_CACHE_MAX]
					  [PERF_COUNT_HW_CACHE_OP_MAX]
					  [PERF_COUNT_HW_CACHE_RESULT_MAX] = {
	[C(L1D)] = {
		/*
		 * The performance counters don't differentiate between read
		 * and write accesses/misses so this isn't strictly correct,
		 * but it's the best we can do. Writes and reads get
		 * combined.
		 */
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]	= ARMV6_PERFCTR_DCACHE_ACCESS,
			[C(RESULT_MISS)]	= ARMV6_PERFCTR_DCACHE_MISS,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]	= ARMV6_PERFCTR_DCACHE_ACCESS,
			[C(RESULT_MISS)]	= ARMV6_PERFCTR_DCACHE_MISS,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= CACHE_OP_UNSUPPORTED,
		},
	},
	[C(L1I)] = {
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= ARMV6_PERFCTR_ICACHE_MISS,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= ARMV6_PERFCTR_ICACHE_MISS,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= CACHE_OP_UNSUPPORTED,
		},
	},
	[C(LL)] = {
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= CACHE_OP_UNSUPPORTED,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= CACHE_OP_UNSUPPORTED,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= CACHE_OP_UNSUPPORTED,
		},
	},
	[C(DTLB)] = {
		/*
		 * The ARM performance counters can count micro DTLB misses,
		 * micro ITLB misses and main TLB misses. There isn't an event
		 * for TLB misses, so use the micro misses here and if users
		 * want the main TLB misses they can use a raw counter.
		 */
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= ARMV6_PERFCTR_DTLB_MISS,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= ARMV6_PERFCTR_DTLB_MISS,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= CACHE_OP_UNSUPPORTED,
		},
	},
	[C(ITLB)] = {
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= ARMV6_PERFCTR_ITLB_MISS,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= ARMV6_PERFCTR_ITLB_MISS,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= CACHE_OP_UNSUPPORTED,
		},
	},
	[C(BPU)] = {
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= CACHE_OP_UNSUPPORTED,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= CACHE_OP_UNSUPPORTED,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]	= CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]	= CACHE_OP_UNSUPPORTED,
		},
	},
};

enum armv6mpcore_perf_types {
	ARMV6MPCORE_PERFCTR_ICACHE_MISS	    = 0x0,
	ARMV6MPCORE_PERFCTR_IBUF_STALL	    = 0x1,
	ARMV6MPCORE_PERFCTR_DDEP_STALL	    = 0x2,
	ARMV6MPCORE_PERFCTR_ITLB_MISS	    = 0x3,
	ARMV6MPCORE_PERFCTR_DTLB_MISS	    = 0x4,
	ARMV6MPCORE_PERFCTR_BR_EXEC	    = 0x5,
	ARMV6MPCORE_PERFCTR_BR_NOTPREDICT   = 0x6,
	ARMV6MPCORE_PERFCTR_BR_MISPREDICT   = 0x7,
	ARMV6MPCORE_PERFCTR_INSTR_EXEC	    = 0x8,
	ARMV6MPCORE_PERFCTR_DCACHE_RDACCESS = 0xA,
	ARMV6MPCORE_PERFCTR_DCACHE_RDMISS   = 0xB,
	ARMV6MPCORE_PERFCTR_DCACHE_WRACCESS = 0xC,
	ARMV6MPCORE_PERFCTR_DCACHE_WRMISS   = 0xD,
	ARMV6MPCORE_PERFCTR_DCACHE_EVICTION = 0xE,
	ARMV6MPCORE_PERFCTR_SW_PC_CHANGE    = 0xF,
	ARMV6MPCORE_PERFCTR_MAIN_TLB_MISS   = 0x10,
	ARMV6MPCORE_PERFCTR_EXPL_MEM_ACCESS = 0x11,
	ARMV6MPCORE_PERFCTR_LSU_FULL_STALL  = 0x12,
	ARMV6MPCORE_PERFCTR_WBUF_DRAINED    = 0x13,
	ARMV6MPCORE_PERFCTR_CPU_CYCLES	    = 0xFF,
};

/*
 * The hardware events that we support. We do support cache operations but
 * we have harvard caches and no way to combine instruction and data
 * accesses/misses in hardware.
 */
static const unsigned armv6mpcore_perf_map[PERF_COUNT_HW_MAX] = {
	[PERF_COUNT_HW_CPU_CYCLES]	    = ARMV6MPCORE_PERFCTR_CPU_CYCLES,
	[PERF_COUNT_HW_INSTRUCTIONS]	    = ARMV6MPCORE_PERFCTR_INSTR_EXEC,
	[PERF_COUNT_HW_CACHE_REFERENCES]    = HW_OP_UNSUPPORTED,
	[PERF_COUNT_HW_CACHE_MISSES]	    = HW_OP_UNSUPPORTED,
	[PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = ARMV6MPCORE_PERFCTR_BR_EXEC,
	[PERF_COUNT_HW_BRANCH_MISSES]	    = ARMV6MPCORE_PERFCTR_BR_MISPREDICT,
	[PERF_COUNT_HW_BUS_CYCLES]	    = HW_OP_UNSUPPORTED,
};

static const unsigned armv6mpcore_perf_cache_map[PERF_COUNT_HW_CACHE_MAX]
					[PERF_COUNT_HW_CACHE_OP_MAX]
					[PERF_COUNT_HW_CACHE_RESULT_MAX] = {
	[C(L1D)] = {
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]  =
				ARMV6MPCORE_PERFCTR_DCACHE_RDACCESS,
			[C(RESULT_MISS)]    =
				ARMV6MPCORE_PERFCTR_DCACHE_RDMISS,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]  =
				ARMV6MPCORE_PERFCTR_DCACHE_WRACCESS,
			[C(RESULT_MISS)]    =
				ARMV6MPCORE_PERFCTR_DCACHE_WRMISS,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = CACHE_OP_UNSUPPORTED,
		},
	},
	[C(L1I)] = {
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = ARMV6MPCORE_PERFCTR_ICACHE_MISS,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = ARMV6MPCORE_PERFCTR_ICACHE_MISS,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = CACHE_OP_UNSUPPORTED,
		},
	},
	[C(LL)] = {
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = CACHE_OP_UNSUPPORTED,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = CACHE_OP_UNSUPPORTED,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = CACHE_OP_UNSUPPORTED,
		},
	},
	[C(DTLB)] = {
		/*
		 * The ARM performance counters can count micro DTLB misses,
		 * micro ITLB misses and main TLB misses. There isn't an event
		 * for TLB misses, so use the micro misses here and if users
		 * want the main TLB misses they can use a raw counter.
		 */
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = ARMV6MPCORE_PERFCTR_DTLB_MISS,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = ARMV6MPCORE_PERFCTR_DTLB_MISS,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = CACHE_OP_UNSUPPORTED,
		},
	},
	[C(ITLB)] = {
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = ARMV6MPCORE_PERFCTR_ITLB_MISS,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = ARMV6MPCORE_PERFCTR_ITLB_MISS,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = CACHE_OP_UNSUPPORTED,
		},
	},
	[C(BPU)] = {
		[C(OP_READ)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = CACHE_OP_UNSUPPORTED,
		},
		[C(OP_WRITE)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = CACHE_OP_UNSUPPORTED,
		},
		[C(OP_PREFETCH)] = {
			[C(RESULT_ACCESS)]  = CACHE_OP_UNSUPPORTED,
			[C(RESULT_MISS)]    = CACHE_OP_UNSUPPORTED,
		},
	},
};

static inline unsigned long
armv6_pmcr_read(void)
{
	u32 val;
	asm volatile("mrc   p15, 0, %0, c15, c12, 0" : "=r"(val));
	return val;
}

static inline void
armv6_pmcr_write(unsigned long val)
{
	asm volatile("mcr   p15, 0, %0, c15, c12, 0" : : "r"(val));
}

#define ARMV6_PMCR_ENABLE		(1 << 0)
#define ARMV6_PMCR_CTR01_RESET		(1 << 1)
#define ARMV6_PMCR_CCOUNT_RESET		(1 << 2)
#define ARMV6_PMCR_CCOUNT_DIV		(1 << 3)
#define ARMV6_PMCR_COUNT0_IEN		(1 << 4)
#define ARMV6_PMCR_COUNT1_IEN		(1 << 5)
#define ARMV6_PMCR_CCOUNT_IEN		(1 << 6)
#define ARMV6_PMCR_COUNT0_OVERFLOW	(1 << 8)
#define ARMV6_PMCR_COUNT1_OVERFLOW	(1 << 9)
#define ARMV6_PMCR_CCOUNT_OVERFLOW	(1 << 10)
#define ARMV6_PMCR_EVT_COUNT0_SHIFT	20
#define ARMV6_PMCR_EVT_COUNT0_MASK	(0xFF << ARMV6_PMCR_EVT_COUNT0_SHIFT)
#define ARMV6_PMCR_EVT_COUNT1_SHIFT	12
#define ARMV6_PMCR_EVT_COUNT1_MASK	(0xFF << ARMV6_PMCR_EVT_COUNT1_SHIFT)

#define ARMV6_PMCR_OVERFLOWED_MASK \
	(ARMV6_PMCR_COUNT0_OVERFLOW | ARMV6_PMCR_COUNT1_OVERFLOW | \
	 ARMV6_PMCR_CCOUNT_OVERFLOW)

static inline int
armv6_pmcr_has_overflowed(unsigned long pmcr)
{
	return pmcr & ARMV6_PMCR_OVERFLOWED_MASK;
}

static inline int
armv6_pmcr_counter_has_overflowed(unsigned long pmcr,
				  enum armv6_counters counter)
{
	int ret = 0;

	if (ARMV6_CYCLE_COUNTER == counter)
		ret = pmcr & ARMV6_PMCR_CCOUNT_OVERFLOW;
	else if (ARMV6_COUNTER0 == counter)
		ret = pmcr & ARMV6_PMCR_COUNT0_OVERFLOW;
	else if (ARMV6_COUNTER1 == counter)
		ret = pmcr & ARMV6_PMCR_COUNT1_OVERFLOW;
	else
		WARN_ONCE(1, "invalid counter number (%d)\n", counter);

	return ret;
}

static inline u32
armv6pmu_read_counter(int counter)
{
	unsigned long value = 0;

	if (ARMV6_CYCLE_COUNTER == counter)
		asm volatile("mrc   p15, 0, %0, c15, c12, 1" : "=r"(value));
	else if (ARMV6_COUNTER0 == counter)
		asm volatile("mrc   p15, 0, %0, c15, c12, 2" : "=r"(value));
	else if (ARMV6_COUNTER1 == counter)
		asm volatile("mrc   p15, 0, %0, c15, c12, 3" : "=r"(value));
	else
		WARN_ONCE(1, "invalid counter number (%d)\n", counter);

	return value;
}

static inline void
armv6pmu_write_counter(int counter,
		       u32 value)
{
	if (ARMV6_CYCLE_COUNTER == counter)
		asm volatile("mcr   p15, 0, %0, c15, c12, 1" : : "r"(value));
	else if (ARMV6_COUNTER0 == counter)
		asm volatile("mcr   p15, 0, %0, c15, c12, 2" : : "r"(value));
	else if (ARMV6_COUNTER1 == counter)
		asm volatile("mcr   p15, 0, %0, c15, c12, 3" : : "r"(value));
	else
		WARN_ONCE(1, "invalid counter number (%d)\n", counter);
}

static void
armv6pmu_enable_event(struct hw_perf_event *hwc,
		      int idx)
{
	unsigned long val, mask, evt, flags;

	if (ARMV6_CYCLE_COUNTER == idx) {
		mask	= 0;
		evt	= ARMV6_PMCR_CCOUNT_IEN;
	} else if (ARMV6_COUNTER0 == idx) {
		mask	= ARMV6_PMCR_EVT_COUNT0_MASK;
		evt	= (hwc->config_base << ARMV6_PMCR_EVT_COUNT0_SHIFT) |
			  ARMV6_PMCR_COUNT0_IEN;
	} else if (ARMV6_COUNTER1 == idx) {
		mask	= ARMV6_PMCR_EVT_COUNT1_MASK;
		evt	= (hwc->config_base << ARMV6_PMCR_EVT_COUNT1_SHIFT) |
			  ARMV6_PMCR_COUNT1_IEN;
	} else {
		WARN_ONCE(1, "invalid counter number (%d)\n", idx);
		return;
	}

	/*
	 * Mask out the current event and set the counter to count the event
	 * that we're interested in.
	 */
	raw_spin_lock_irqsave(&pmu_lock, flags);
	val = armv6_pmcr_read();
	val &= ~mask;
	val |= evt;
	armv6_pmcr_write(val);
	raw_spin_unlock_irqrestore(&pmu_lock, flags);
}

static irqreturn_t
armv6pmu_handle_irq(int irq_num,
		    void *dev)
{
	unsigned long pmcr = armv6_pmcr_read();
	struct perf_sample_data data;
	struct cpu_hw_events *cpuc;
	struct pt_regs *regs;
	int idx;

	if (!armv6_pmcr_has_overflowed(pmcr))
		return IRQ_NONE;

	regs = get_irq_regs();

	/*
	 * The interrupts are cleared by writing the overflow flags back to
	 * the control register. All of the other bits don't have any effect
	 * if they are rewritten, so write the whole value back.
	 */
	armv6_pmcr_write(pmcr);

	perf_sample_data_init(&data, 0);

	cpuc = &__get_cpu_var(cpu_hw_events);
	for (idx = 0; idx <= armpmu->num_events; ++idx) {
		struct perf_event *event = cpuc->events[idx];
		struct hw_perf_event *hwc;

		if (!test_bit(idx, cpuc->active_mask))
			continue;

		/*
		 * We have a single interrupt for all counters. Check that
		 * each counter has overflowed before we process it.
		 */
		if (!armv6_pmcr_counter_has_overflowed(pmcr, idx))
			continue;

		hwc = &event->hw;
		armpmu_event_update(event, hwc, idx);
		data.period = event->hw.last_period;
		if (!armpmu_event_set_period(event, hwc, idx))
			continue;

		if (perf_event_overflow(event, 0, &data, regs))
			armpmu->disable(hwc, idx);
	}

	/*
	 * Handle the pending perf events.
	 *
	 * Note: this call *must* be run with interrupts disabled. For
	 * platforms that can have the PMU interrupts raised as an NMI, this
	 * will not work.
	 */
	irq_work_run();

	return IRQ_HANDLED;
}

static void
armv6pmu_start(void)
{
	unsigned long flags, val;

	raw_spin_lock_irqsave(&pmu_lock, flags);
	val = armv6_pmcr_read();
	val |= ARMV6_PMCR_ENABLE;
	armv6_pmcr_write(val);
	raw_spin_unlock_irqrestore(&pmu_lock, flags);
}

static void
armv6pmu_stop(void)
{
	unsigned long flags, val;

	raw_spin_lock_irqsave(&pmu_lock, flags);
	val = armv6_pmcr_read();
	val &= ~ARMV6_PMCR_ENABLE;
	armv6_pmcr_write(val);
	raw_spin_unlock_irqrestore(&pmu_lock, flags);
}

static int
armv6pmu_get_event_idx(struct cpu_hw_events *cpuc,
		       struct hw_perf_event *event)
{
	/* Always place a cycle counter into the cycle counter. */
	if (ARMV6_PERFCTR_CPU_CYCLES == event->config_base) {
		if (test_and_set_bit(ARMV6_CYCLE_COUNTER, cpuc->used_mask))
			return -EAGAIN;

		return ARMV6_CYCLE_COUNTER;
	} else {
		/*
		 * For anything other than a cycle counter, try and use
		 * counter0 and counter1.
		 */
		if (!test_and_set_bit(ARMV6_COUNTER1, cpuc->used_mask))
			return ARMV6_COUNTER1;

		if (!test_and_set_bit(ARMV6_COUNTER0, cpuc->used_mask))
			return ARMV6_COUNTER0;

		/* The counters are all in use. */
		return -EAGAIN;
	}
}

static void
armv6pmu_disable_event(struct hw_perf_event *hwc,
		       int idx)
{
	unsigned long val, mask, evt, flags;

	if (ARMV6_CYCLE_COUNTER == idx) {
		mask	= ARMV6_PMCR_CCOUNT_IEN;
		evt	= 0;
	} else if (ARMV6_COUNTER0 == idx) {
		mask	= ARMV6_PMCR_COUNT0_IEN | ARMV6_PMCR_EVT_COUNT0_MASK;
		evt	= ARMV6_PERFCTR_NOP << ARMV6_PMCR_EVT_COUNT0_SHIFT;
	} else if (ARMV6_COUNTER1 == idx) {
		mask	= ARMV6_PMCR_COUNT1_IEN | ARMV6_PMCR_EVT_COUNT1_MASK;
		evt	= ARMV6_PERFCTR_NOP << ARMV6_PMCR_EVT_COUNT1_SHIFT;
	} else {
		WARN_ONCE(1, "invalid counter number (%d)\n", idx);
		return;
	}

	/*
	 * Mask out the current event and set the counter to count the number
	 * of ETM bus signal assertion cycles. The external reporting should
	 * be disabled and so this should never increment.
	 */
	raw_spin_lock_irqsave(&pmu_lock, flags);
	val = armv6_pmcr_read();
	val &= ~mask;
	val |= evt;
	armv6_pmcr_write(val);
	raw_spin_unlock_irqrestore(&pmu_lock, flags);
}

static void
armv6mpcore_pmu_disable_event(struct hw_perf_event *hwc,
			      int idx)
{
	unsigned long val, mask, flags, evt = 0;

	if (ARMV6_CYCLE_COUNTER == idx) {
		mask	= ARMV6_PMCR_CCOUNT_IEN;
	} else if (ARMV6_COUNTER0 == idx) {
		mask	= ARMV6_PMCR_COUNT0_IEN;
	} else if (ARMV6_COUNTER1 == idx) {
		mask	= ARMV6_PMCR_COUNT1_IEN;
	} else {
		WARN_ONCE(1, "invalid counter number (%d)\n", idx);
		return;
	}

	/*
	 * Unlike UP ARMv6, we don't have a way of stopping the counters. We
	 * simply disable the interrupt reporting.
	 */
	raw_spin_lock_irqsave(&pmu_lock, flags);
	val = armv6_pmcr_read();
	val &= ~mask;
	val |= evt;
	armv6_pmcr_write(val);
	raw_spin_unlock_irqrestore(&pmu_lock, flags);
}

static const struct arm_pmu armv6pmu = {
	.id			= ARM_PERF_PMU_ID_V6,
	.name			= "v6",
	.handle_irq		= armv6pmu_handle_irq,
	.enable			= armv6pmu_enable_event,
	.disable		= armv6pmu_disable_event,
	.read_counter		= armv6pmu_read_counter,
	.write_counter		= armv6pmu_write_counter,
	.get_event_idx		= armv6pmu_get_event_idx,
	.start			= armv6pmu_start,
	.stop			= armv6pmu_stop,
	.cache_map		= &armv6_perf_cache_map,
	.event_map		= &armv6_perf_map,
	.raw_event_mask		= 0xFF,
	.num_events		= 3,
	.max_period		= (1LLU << 32) - 1,
};

static const struct arm_pmu *__init armv6pmu_init(void)
{
	return &armv6pmu;
}

/*
 * ARMv6mpcore is almost identical to single core ARMv6 with the exception
 * that some of the events have different enumerations and that there is no
 * *hack* to stop the programmable counters. To stop the counters we simply
 * disable the interrupt reporting and update the event. When unthrottling we
 * reset the period and enable the interrupt reporting.
 */
static const struct arm_pmu armv6mpcore_pmu = {
	.id			= ARM_PERF_PMU_ID_V6MP,
	.name			= "v6mpcore",
	.handle_irq		= armv6pmu_handle_irq,
	.enable			= armv6pmu_enable_event,
	.disable		= armv6mpcore_pmu_disable_event,
	.read_counter		= armv6pmu_read_counter,
	.write_counter		= armv6pmu_write_counter,
	.get_event_idx		= armv6pmu_get_event_idx,
	.start			= armv6pmu_start,
	.stop			= armv6pmu_stop,
	.cache_map		= &armv6mpcore_perf_cache_map,
	.event_map		= &armv6mpcore_perf_map,
	.raw_event_mask		= 0xFF,
	.num_events		= 3,
	.max_period		= (1LLU << 32) - 1,
};

static const struct arm_pmu *__init armv6mpcore_pmu_init(void)
{
	return &armv6mpcore_pmu;
}
#else
static const struct arm_pmu *__init armv6pmu_init(void)
{
	return NULL;
}

static const struct arm_pmu *__init armv6mpcore_pmu_init(void)
{
	return NULL;
}
#endif	/* CONFIG_CPU_V6 || CONFIG_CPU_V6K */