summaryrefslogtreecommitdiff
path: root/drivers/perf/arm_dsu_pmu.c
blob: 8223c49bd082c2d6568de7d26be1cd35b8757b9a (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * ARM DynamIQ Shared Unit (DSU) PMU driver
 *
 * Copyright (C) ARM Limited, 2017.
 *
 * Based on ARM CCI-PMU, ARMv8 PMU-v3 drivers.
 */

#define PMUNAME		"arm_dsu"
#define DRVNAME		PMUNAME "_pmu"
#define pr_fmt(fmt)	DRVNAME ": " fmt

#include <linux/acpi.h>
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/cpumask.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/sysfs.h>
#include <linux/types.h>

#include <asm/arm_dsu_pmu.h>
#include <asm/local64.h>

/* PMU event codes */
#define DSU_PMU_EVT_CYCLES		0x11
#define DSU_PMU_EVT_CHAIN		0x1e

#define DSU_PMU_MAX_COMMON_EVENTS	0x40

#define DSU_PMU_MAX_HW_CNTRS		32
#define DSU_PMU_HW_COUNTER_MASK		(DSU_PMU_MAX_HW_CNTRS - 1)

#define CLUSTERPMCR_E			BIT(0)
#define CLUSTERPMCR_P			BIT(1)
#define CLUSTERPMCR_C			BIT(2)
#define CLUSTERPMCR_N_SHIFT		11
#define CLUSTERPMCR_N_MASK		0x1f
#define CLUSTERPMCR_IDCODE_SHIFT	16
#define CLUSTERPMCR_IDCODE_MASK		0xff
#define CLUSTERPMCR_IMP_SHIFT		24
#define CLUSTERPMCR_IMP_MASK		0xff
#define CLUSTERPMCR_RES_MASK		0x7e8
#define CLUSTERPMCR_RES_VAL		0x40

#define DSU_ACTIVE_CPU_MASK		0x0
#define DSU_ASSOCIATED_CPU_MASK		0x1

/*
 * We use the index of the counters as they appear in the counter
 * bit maps in the PMU registers (e.g CLUSTERPMSELR).
 * i.e,
 *	counter 0	- Bit 0
 *	counter 1	- Bit 1
 *	...
 *	Cycle counter	- Bit 31
 */
#define DSU_PMU_IDX_CYCLE_COUNTER	31

/* All event counters are 32bit, with a 64bit Cycle counter */
#define DSU_PMU_COUNTER_WIDTH(idx)	\
	(((idx) == DSU_PMU_IDX_CYCLE_COUNTER) ? 64 : 32)

#define DSU_PMU_COUNTER_MASK(idx)	\
	GENMASK_ULL((DSU_PMU_COUNTER_WIDTH((idx)) - 1), 0)

#define DSU_EXT_ATTR(_name, _func, _config)		\
	(&((struct dev_ext_attribute[]) {				\
		{							\
			.attr = __ATTR(_name, 0444, _func, NULL),	\
			.var = (void *)_config				\
		}							\
	})[0].attr.attr)

#define DSU_EVENT_ATTR(_name, _config)		\
	DSU_EXT_ATTR(_name, dsu_pmu_sysfs_event_show, (unsigned long)_config)

#define DSU_FORMAT_ATTR(_name, _config)		\
	DSU_EXT_ATTR(_name, dsu_pmu_sysfs_format_show, (char *)_config)

#define DSU_CPUMASK_ATTR(_name, _config)	\
	DSU_EXT_ATTR(_name, dsu_pmu_cpumask_show, (unsigned long)_config)

struct dsu_hw_events {
	DECLARE_BITMAP(used_mask, DSU_PMU_MAX_HW_CNTRS);
	struct perf_event	*events[DSU_PMU_MAX_HW_CNTRS];
};

/*
 * struct dsu_pmu	- DSU PMU descriptor
 *
 * @pmu_lock		: Protects accesses to DSU PMU register from normal vs
 *			  interrupt handler contexts.
 * @hw_events		: Holds the event counter state.
 * @associated_cpus	: CPUs attached to the DSU.
 * @active_cpu		: CPU to which the PMU is bound for accesses.
 * @cpuhp_node		: Node for CPU hotplug notifier link.
 * @num_counters	: Number of event counters implemented by the PMU,
 *			  excluding the cycle counter.
 * @irq			: Interrupt line for counter overflow.
 * @cpmceid_bitmap	: Bitmap for the availability of architected common
 *			  events (event_code < 0x40).
 */
struct dsu_pmu {
	struct pmu			pmu;
	struct device			*dev;
	raw_spinlock_t			pmu_lock;
	struct dsu_hw_events		hw_events;
	cpumask_t			associated_cpus;
	cpumask_t			active_cpu;
	struct hlist_node		cpuhp_node;
	s8				num_counters;
	int				irq;
	DECLARE_BITMAP(cpmceid_bitmap, DSU_PMU_MAX_COMMON_EVENTS);
};

static unsigned long dsu_pmu_cpuhp_state;

static inline struct dsu_pmu *to_dsu_pmu(struct pmu *pmu)
{
	return container_of(pmu, struct dsu_pmu, pmu);
}

static ssize_t dsu_pmu_sysfs_event_show(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	struct dev_ext_attribute *eattr = container_of(attr,
					struct dev_ext_attribute, attr);
	return sysfs_emit(buf, "event=0x%lx\n", (unsigned long)eattr->var);
}

static ssize_t dsu_pmu_sysfs_format_show(struct device *dev,
					 struct device_attribute *attr,
					 char *buf)
{
	struct dev_ext_attribute *eattr = container_of(attr,
					struct dev_ext_attribute, attr);
	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
}

static ssize_t dsu_pmu_cpumask_show(struct device *dev,
				    struct device_attribute *attr,
				    char *buf)
{
	struct pmu *pmu = dev_get_drvdata(dev);
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(pmu);
	struct dev_ext_attribute *eattr = container_of(attr,
					struct dev_ext_attribute, attr);
	unsigned long mask_id = (unsigned long)eattr->var;
	const cpumask_t *cpumask;

	switch (mask_id) {
	case DSU_ACTIVE_CPU_MASK:
		cpumask = &dsu_pmu->active_cpu;
		break;
	case DSU_ASSOCIATED_CPU_MASK:
		cpumask = &dsu_pmu->associated_cpus;
		break;
	default:
		return 0;
	}
	return cpumap_print_to_pagebuf(true, buf, cpumask);
}

static struct attribute *dsu_pmu_format_attrs[] = {
	DSU_FORMAT_ATTR(event, "config:0-31"),
	NULL,
};

static const struct attribute_group dsu_pmu_format_attr_group = {
	.name = "format",
	.attrs = dsu_pmu_format_attrs,
};

static struct attribute *dsu_pmu_event_attrs[] = {
	DSU_EVENT_ATTR(cycles, 0x11),
	DSU_EVENT_ATTR(bus_access, 0x19),
	DSU_EVENT_ATTR(memory_error, 0x1a),
	DSU_EVENT_ATTR(bus_cycles, 0x1d),
	DSU_EVENT_ATTR(l3d_cache_allocate, 0x29),
	DSU_EVENT_ATTR(l3d_cache_refill, 0x2a),
	DSU_EVENT_ATTR(l3d_cache, 0x2b),
	DSU_EVENT_ATTR(l3d_cache_wb, 0x2c),
	NULL,
};

static umode_t
dsu_pmu_event_attr_is_visible(struct kobject *kobj, struct attribute *attr,
				int unused)
{
	struct pmu *pmu = dev_get_drvdata(kobj_to_dev(kobj));
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(pmu);
	struct dev_ext_attribute *eattr = container_of(attr,
					struct dev_ext_attribute, attr.attr);
	unsigned long evt = (unsigned long)eattr->var;

	return test_bit(evt, dsu_pmu->cpmceid_bitmap) ? attr->mode : 0;
}

static const struct attribute_group dsu_pmu_events_attr_group = {
	.name = "events",
	.attrs = dsu_pmu_event_attrs,
	.is_visible = dsu_pmu_event_attr_is_visible,
};

static struct attribute *dsu_pmu_cpumask_attrs[] = {
	DSU_CPUMASK_ATTR(cpumask, DSU_ACTIVE_CPU_MASK),
	DSU_CPUMASK_ATTR(associated_cpus, DSU_ASSOCIATED_CPU_MASK),
	NULL,
};

static const struct attribute_group dsu_pmu_cpumask_attr_group = {
	.attrs = dsu_pmu_cpumask_attrs,
};

static const struct attribute_group *dsu_pmu_attr_groups[] = {
	&dsu_pmu_cpumask_attr_group,
	&dsu_pmu_events_attr_group,
	&dsu_pmu_format_attr_group,
	NULL,
};

static int dsu_pmu_get_online_cpu_any_but(struct dsu_pmu *dsu_pmu, int cpu)
{
	struct cpumask online_supported;

	cpumask_and(&online_supported,
			 &dsu_pmu->associated_cpus, cpu_online_mask);
	return cpumask_any_but(&online_supported, cpu);
}

static inline bool dsu_pmu_counter_valid(struct dsu_pmu *dsu_pmu, u32 idx)
{
	return (idx < dsu_pmu->num_counters) ||
	       (idx == DSU_PMU_IDX_CYCLE_COUNTER);
}

static inline u64 dsu_pmu_read_counter(struct perf_event *event)
{
	u64 val;
	unsigned long flags;
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(event->pmu);
	int idx = event->hw.idx;

	if (WARN_ON(!cpumask_test_cpu(smp_processor_id(),
				 &dsu_pmu->associated_cpus)))
		return 0;

	if (!dsu_pmu_counter_valid(dsu_pmu, idx)) {
		dev_err(event->pmu->dev,
			"Trying reading invalid counter %d\n", idx);
		return 0;
	}

	raw_spin_lock_irqsave(&dsu_pmu->pmu_lock, flags);
	if (idx == DSU_PMU_IDX_CYCLE_COUNTER)
		val = __dsu_pmu_read_pmccntr();
	else
		val = __dsu_pmu_read_counter(idx);
	raw_spin_unlock_irqrestore(&dsu_pmu->pmu_lock, flags);

	return val;
}

static void dsu_pmu_write_counter(struct perf_event *event, u64 val)
{
	unsigned long flags;
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(event->pmu);
	int idx = event->hw.idx;

	if (WARN_ON(!cpumask_test_cpu(smp_processor_id(),
			 &dsu_pmu->associated_cpus)))
		return;

	if (!dsu_pmu_counter_valid(dsu_pmu, idx)) {
		dev_err(event->pmu->dev,
			"writing to invalid counter %d\n", idx);
		return;
	}

	raw_spin_lock_irqsave(&dsu_pmu->pmu_lock, flags);
	if (idx == DSU_PMU_IDX_CYCLE_COUNTER)
		__dsu_pmu_write_pmccntr(val);
	else
		__dsu_pmu_write_counter(idx, val);
	raw_spin_unlock_irqrestore(&dsu_pmu->pmu_lock, flags);
}

static int dsu_pmu_get_event_idx(struct dsu_hw_events *hw_events,
				 struct perf_event *event)
{
	int idx;
	unsigned long evtype = event->attr.config;
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(event->pmu);
	unsigned long *used_mask = hw_events->used_mask;

	if (evtype == DSU_PMU_EVT_CYCLES) {
		if (test_and_set_bit(DSU_PMU_IDX_CYCLE_COUNTER, used_mask))
			return -EAGAIN;
		return DSU_PMU_IDX_CYCLE_COUNTER;
	}

	idx = find_first_zero_bit(used_mask, dsu_pmu->num_counters);
	if (idx >= dsu_pmu->num_counters)
		return -EAGAIN;
	set_bit(idx, hw_events->used_mask);
	return idx;
}

static void dsu_pmu_enable_counter(struct dsu_pmu *dsu_pmu, int idx)
{
	__dsu_pmu_counter_interrupt_enable(idx);
	__dsu_pmu_enable_counter(idx);
}

static void dsu_pmu_disable_counter(struct dsu_pmu *dsu_pmu, int idx)
{
	__dsu_pmu_disable_counter(idx);
	__dsu_pmu_counter_interrupt_disable(idx);
}

static inline void dsu_pmu_set_event(struct dsu_pmu *dsu_pmu,
					struct perf_event *event)
{
	int idx = event->hw.idx;
	unsigned long flags;

	if (!dsu_pmu_counter_valid(dsu_pmu, idx)) {
		dev_err(event->pmu->dev,
			"Trying to set invalid counter %d\n", idx);
		return;
	}

	raw_spin_lock_irqsave(&dsu_pmu->pmu_lock, flags);
	__dsu_pmu_set_event(idx, event->hw.config_base);
	raw_spin_unlock_irqrestore(&dsu_pmu->pmu_lock, flags);
}

static void dsu_pmu_event_update(struct perf_event *event)
{
	struct hw_perf_event *hwc = &event->hw;
	u64 delta, prev_count, new_count;

	do {
		/* We may also be called from the irq handler */
		prev_count = local64_read(&hwc->prev_count);
		new_count = dsu_pmu_read_counter(event);
	} while (local64_cmpxchg(&hwc->prev_count, prev_count, new_count) !=
			prev_count);
	delta = (new_count - prev_count) & DSU_PMU_COUNTER_MASK(hwc->idx);
	local64_add(delta, &event->count);
}

static void dsu_pmu_read(struct perf_event *event)
{
	dsu_pmu_event_update(event);
}

static inline u32 dsu_pmu_get_reset_overflow(void)
{
	return __dsu_pmu_get_reset_overflow();
}

/**
 * dsu_pmu_set_event_period: Set the period for the counter.
 *
 * All DSU PMU event counters, except the cycle counter are 32bit
 * counters. To handle cases of extreme interrupt latency, we program
 * the counter with half of the max count for the counters.
 */
static void dsu_pmu_set_event_period(struct perf_event *event)
{
	int idx = event->hw.idx;
	u64 val = DSU_PMU_COUNTER_MASK(idx) >> 1;

	local64_set(&event->hw.prev_count, val);
	dsu_pmu_write_counter(event, val);
}

static irqreturn_t dsu_pmu_handle_irq(int irq_num, void *dev)
{
	int i;
	bool handled = false;
	struct dsu_pmu *dsu_pmu = dev;
	struct dsu_hw_events *hw_events = &dsu_pmu->hw_events;
	unsigned long overflow;

	overflow = dsu_pmu_get_reset_overflow();
	if (!overflow)
		return IRQ_NONE;

	for_each_set_bit(i, &overflow, DSU_PMU_MAX_HW_CNTRS) {
		struct perf_event *event = hw_events->events[i];

		if (!event)
			continue;
		dsu_pmu_event_update(event);
		dsu_pmu_set_event_period(event);
		handled = true;
	}

	return IRQ_RETVAL(handled);
}

static void dsu_pmu_start(struct perf_event *event, int pmu_flags)
{
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(event->pmu);

	/* We always reprogram the counter */
	if (pmu_flags & PERF_EF_RELOAD)
		WARN_ON(!(event->hw.state & PERF_HES_UPTODATE));
	dsu_pmu_set_event_period(event);
	if (event->hw.idx != DSU_PMU_IDX_CYCLE_COUNTER)
		dsu_pmu_set_event(dsu_pmu, event);
	event->hw.state = 0;
	dsu_pmu_enable_counter(dsu_pmu, event->hw.idx);
}

static void dsu_pmu_stop(struct perf_event *event, int pmu_flags)
{
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(event->pmu);

	if (event->hw.state & PERF_HES_STOPPED)
		return;
	dsu_pmu_disable_counter(dsu_pmu, event->hw.idx);
	dsu_pmu_event_update(event);
	event->hw.state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
}

static int dsu_pmu_add(struct perf_event *event, int flags)
{
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(event->pmu);
	struct dsu_hw_events *hw_events = &dsu_pmu->hw_events;
	struct hw_perf_event *hwc = &event->hw;
	int idx;

	if (WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(),
					   &dsu_pmu->associated_cpus)))
		return -ENOENT;

	idx = dsu_pmu_get_event_idx(hw_events, event);
	if (idx < 0)
		return idx;

	hwc->idx = idx;
	hw_events->events[idx] = event;
	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;

	if (flags & PERF_EF_START)
		dsu_pmu_start(event, PERF_EF_RELOAD);

	perf_event_update_userpage(event);
	return 0;
}

static void dsu_pmu_del(struct perf_event *event, int flags)
{
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(event->pmu);
	struct dsu_hw_events *hw_events = &dsu_pmu->hw_events;
	struct hw_perf_event *hwc = &event->hw;
	int idx = hwc->idx;

	dsu_pmu_stop(event, PERF_EF_UPDATE);
	hw_events->events[idx] = NULL;
	clear_bit(idx, hw_events->used_mask);
	perf_event_update_userpage(event);
}

static void dsu_pmu_enable(struct pmu *pmu)
{
	u32 pmcr;
	unsigned long flags;
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(pmu);

	/* If no counters are added, skip enabling the PMU */
	if (bitmap_empty(dsu_pmu->hw_events.used_mask, DSU_PMU_MAX_HW_CNTRS))
		return;

	raw_spin_lock_irqsave(&dsu_pmu->pmu_lock, flags);
	pmcr = __dsu_pmu_read_pmcr();
	pmcr |= CLUSTERPMCR_E;
	__dsu_pmu_write_pmcr(pmcr);
	raw_spin_unlock_irqrestore(&dsu_pmu->pmu_lock, flags);
}

static void dsu_pmu_disable(struct pmu *pmu)
{
	u32 pmcr;
	unsigned long flags;
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(pmu);

	raw_spin_lock_irqsave(&dsu_pmu->pmu_lock, flags);
	pmcr = __dsu_pmu_read_pmcr();
	pmcr &= ~CLUSTERPMCR_E;
	__dsu_pmu_write_pmcr(pmcr);
	raw_spin_unlock_irqrestore(&dsu_pmu->pmu_lock, flags);
}

static bool dsu_pmu_validate_event(struct pmu *pmu,
				  struct dsu_hw_events *hw_events,
				  struct perf_event *event)
{
	if (is_software_event(event))
		return true;
	/* Reject groups spanning multiple HW PMUs. */
	if (event->pmu != pmu)
		return false;
	return dsu_pmu_get_event_idx(hw_events, event) >= 0;
}

/*
 * Make sure the group of events can be scheduled at once
 * on the PMU.
 */
static bool dsu_pmu_validate_group(struct perf_event *event)
{
	struct perf_event *sibling, *leader = event->group_leader;
	struct dsu_hw_events fake_hw;

	if (event->group_leader == event)
		return true;

	memset(fake_hw.used_mask, 0, sizeof(fake_hw.used_mask));
	if (!dsu_pmu_validate_event(event->pmu, &fake_hw, leader))
		return false;
	for_each_sibling_event(sibling, leader) {
		if (!dsu_pmu_validate_event(event->pmu, &fake_hw, sibling))
			return false;
	}
	return dsu_pmu_validate_event(event->pmu, &fake_hw, event);
}

static int dsu_pmu_event_init(struct perf_event *event)
{
	struct dsu_pmu *dsu_pmu = to_dsu_pmu(event->pmu);

	if (event->attr.type != event->pmu->type)
		return -ENOENT;

	/* We don't support sampling */
	if (is_sampling_event(event)) {
		dev_dbg(dsu_pmu->pmu.dev, "Can't support sampling events\n");
		return -EOPNOTSUPP;
	}

	/* We cannot support task bound events */
	if (event->cpu < 0 || event->attach_state & PERF_ATTACH_TASK) {
		dev_dbg(dsu_pmu->pmu.dev, "Can't support per-task counters\n");
		return -EINVAL;
	}

	if (has_branch_stack(event)) {
		dev_dbg(dsu_pmu->pmu.dev, "Can't support filtering\n");
		return -EINVAL;
	}

	if (!cpumask_test_cpu(event->cpu, &dsu_pmu->associated_cpus)) {
		dev_dbg(dsu_pmu->pmu.dev,
			 "Requested cpu is not associated with the DSU\n");
		return -EINVAL;
	}
	/*
	 * Choose the current active CPU to read the events. We don't want
	 * to migrate the event contexts, irq handling etc to the requested
	 * CPU. As long as the requested CPU is within the same DSU, we
	 * are fine.
	 */
	event->cpu = cpumask_first(&dsu_pmu->active_cpu);
	if (event->cpu >= nr_cpu_ids)
		return -EINVAL;
	if (!dsu_pmu_validate_group(event))
		return -EINVAL;

	event->hw.config_base = event->attr.config;
	return 0;
}

static struct dsu_pmu *dsu_pmu_alloc(struct platform_device *pdev)
{
	struct dsu_pmu *dsu_pmu;

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

	raw_spin_lock_init(&dsu_pmu->pmu_lock);
	/*
	 * Initialise the number of counters to -1, until we probe
	 * the real number on a connected CPU.
	 */
	dsu_pmu->num_counters = -1;
	return dsu_pmu;
}

/**
 * dsu_pmu_dt_get_cpus: Get the list of CPUs in the cluster
 * from device tree.
 */
static int dsu_pmu_dt_get_cpus(struct device *dev, cpumask_t *mask)
{
	int i = 0, n, cpu;
	struct device_node *cpu_node;

	n = of_count_phandle_with_args(dev->of_node, "cpus", NULL);
	if (n <= 0)
		return -ENODEV;
	for (; i < n; i++) {
		cpu_node = of_parse_phandle(dev->of_node, "cpus", i);
		if (!cpu_node)
			break;
		cpu = of_cpu_node_to_id(cpu_node);
		of_node_put(cpu_node);
		/*
		 * We have to ignore the failures here and continue scanning
		 * the list to handle cases where the nr_cpus could be capped
		 * in the running kernel.
		 */
		if (cpu < 0)
			continue;
		cpumask_set_cpu(cpu, mask);
	}
	return 0;
}

/**
 * dsu_pmu_acpi_get_cpus: Get the list of CPUs in the cluster
 * from ACPI.
 */
static int dsu_pmu_acpi_get_cpus(struct device *dev, cpumask_t *mask)
{
#ifdef CONFIG_ACPI
	struct acpi_device *parent_adev = acpi_dev_parent(ACPI_COMPANION(dev));
	int cpu;

	/*
	 * A dsu pmu node is inside a cluster parent node along with cpu nodes.
	 * We need to find out all cpus that have the same parent with this pmu.
	 */
	for_each_possible_cpu(cpu) {
		struct acpi_device *acpi_dev;
		struct device *cpu_dev = get_cpu_device(cpu);

		if (!cpu_dev)
			continue;

		acpi_dev = ACPI_COMPANION(cpu_dev);
		if (acpi_dev && acpi_dev_parent(acpi_dev) == parent_adev)
			cpumask_set_cpu(cpu, mask);
	}
#endif

	return 0;
}

/*
 * dsu_pmu_probe_pmu: Probe the PMU details on a CPU in the cluster.
 */
static void dsu_pmu_probe_pmu(struct dsu_pmu *dsu_pmu)
{
	u64 num_counters;
	u32 cpmceid[2];

	num_counters = (__dsu_pmu_read_pmcr() >> CLUSTERPMCR_N_SHIFT) &
						CLUSTERPMCR_N_MASK;
	/* We can only support up to 31 independent counters */
	if (WARN_ON(num_counters > 31))
		num_counters = 31;
	dsu_pmu->num_counters = num_counters;
	if (!dsu_pmu->num_counters)
		return;
	cpmceid[0] = __dsu_pmu_read_pmceid(0);
	cpmceid[1] = __dsu_pmu_read_pmceid(1);
	bitmap_from_arr32(dsu_pmu->cpmceid_bitmap, cpmceid,
			  DSU_PMU_MAX_COMMON_EVENTS);
}

static void dsu_pmu_set_active_cpu(int cpu, struct dsu_pmu *dsu_pmu)
{
	cpumask_set_cpu(cpu, &dsu_pmu->active_cpu);
	if (irq_set_affinity(dsu_pmu->irq, &dsu_pmu->active_cpu))
		pr_warn("Failed to set irq affinity to %d\n", cpu);
}

/*
 * dsu_pmu_init_pmu: Initialise the DSU PMU configurations if
 * we haven't done it already.
 */
static void dsu_pmu_init_pmu(struct dsu_pmu *dsu_pmu)
{
	if (dsu_pmu->num_counters == -1)
		dsu_pmu_probe_pmu(dsu_pmu);
	/* Reset the interrupt overflow mask */
	dsu_pmu_get_reset_overflow();
}

static int dsu_pmu_device_probe(struct platform_device *pdev)
{
	int irq, rc;
	struct dsu_pmu *dsu_pmu;
	struct fwnode_handle *fwnode = dev_fwnode(&pdev->dev);
	char *name;
	static atomic_t pmu_idx = ATOMIC_INIT(-1);

	dsu_pmu = dsu_pmu_alloc(pdev);
	if (IS_ERR(dsu_pmu))
		return PTR_ERR(dsu_pmu);

	if (is_of_node(fwnode))
		rc = dsu_pmu_dt_get_cpus(&pdev->dev, &dsu_pmu->associated_cpus);
	else if (is_acpi_device_node(fwnode))
		rc = dsu_pmu_acpi_get_cpus(&pdev->dev, &dsu_pmu->associated_cpus);
	else
		return -ENOENT;

	if (rc) {
		dev_warn(&pdev->dev, "Failed to parse the CPUs\n");
		return rc;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return -EINVAL;

	name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s_%d",
				PMUNAME, atomic_inc_return(&pmu_idx));
	if (!name)
		return -ENOMEM;
	rc = devm_request_irq(&pdev->dev, irq, dsu_pmu_handle_irq,
			      IRQF_NOBALANCING, name, dsu_pmu);
	if (rc) {
		dev_warn(&pdev->dev, "Failed to request IRQ %d\n", irq);
		return rc;
	}

	dsu_pmu->irq = irq;
	platform_set_drvdata(pdev, dsu_pmu);
	rc = cpuhp_state_add_instance(dsu_pmu_cpuhp_state,
						&dsu_pmu->cpuhp_node);
	if (rc)
		return rc;

	dsu_pmu->pmu = (struct pmu) {
		.task_ctx_nr	= perf_invalid_context,
		.module		= THIS_MODULE,
		.pmu_enable	= dsu_pmu_enable,
		.pmu_disable	= dsu_pmu_disable,
		.event_init	= dsu_pmu_event_init,
		.add		= dsu_pmu_add,
		.del		= dsu_pmu_del,
		.start		= dsu_pmu_start,
		.stop		= dsu_pmu_stop,
		.read		= dsu_pmu_read,

		.attr_groups	= dsu_pmu_attr_groups,
		.capabilities	= PERF_PMU_CAP_NO_EXCLUDE,
	};

	rc = perf_pmu_register(&dsu_pmu->pmu, name, -1);
	if (rc) {
		cpuhp_state_remove_instance(dsu_pmu_cpuhp_state,
						 &dsu_pmu->cpuhp_node);
	}

	return rc;
}

static int dsu_pmu_device_remove(struct platform_device *pdev)
{
	struct dsu_pmu *dsu_pmu = platform_get_drvdata(pdev);

	perf_pmu_unregister(&dsu_pmu->pmu);
	cpuhp_state_remove_instance(dsu_pmu_cpuhp_state, &dsu_pmu->cpuhp_node);

	return 0;
}

static const struct of_device_id dsu_pmu_of_match[] = {
	{ .compatible = "arm,dsu-pmu", },
	{},
};
MODULE_DEVICE_TABLE(of, dsu_pmu_of_match);

#ifdef CONFIG_ACPI
static const struct acpi_device_id dsu_pmu_acpi_match[] = {
	{ "ARMHD500", 0},
	{},
};
MODULE_DEVICE_TABLE(acpi, dsu_pmu_acpi_match);
#endif

static struct platform_driver dsu_pmu_driver = {
	.driver = {
		.name	= DRVNAME,
		.of_match_table = of_match_ptr(dsu_pmu_of_match),
		.acpi_match_table = ACPI_PTR(dsu_pmu_acpi_match),
		.suppress_bind_attrs = true,
	},
	.probe = dsu_pmu_device_probe,
	.remove = dsu_pmu_device_remove,
};

static int dsu_pmu_cpu_online(unsigned int cpu, struct hlist_node *node)
{
	struct dsu_pmu *dsu_pmu = hlist_entry_safe(node, struct dsu_pmu,
						   cpuhp_node);

	if (!cpumask_test_cpu(cpu, &dsu_pmu->associated_cpus))
		return 0;

	/* If the PMU is already managed, there is nothing to do */
	if (!cpumask_empty(&dsu_pmu->active_cpu))
		return 0;

	dsu_pmu_init_pmu(dsu_pmu);
	dsu_pmu_set_active_cpu(cpu, dsu_pmu);

	return 0;
}

static int dsu_pmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)
{
	int dst;
	struct dsu_pmu *dsu_pmu = hlist_entry_safe(node, struct dsu_pmu,
						   cpuhp_node);

	if (!cpumask_test_and_clear_cpu(cpu, &dsu_pmu->active_cpu))
		return 0;

	dst = dsu_pmu_get_online_cpu_any_but(dsu_pmu, cpu);
	/* If there are no active CPUs in the DSU, leave IRQ disabled */
	if (dst >= nr_cpu_ids)
		return 0;

	perf_pmu_migrate_context(&dsu_pmu->pmu, cpu, dst);
	dsu_pmu_set_active_cpu(dst, dsu_pmu);

	return 0;
}

static int __init dsu_pmu_init(void)
{
	int ret;

	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
					DRVNAME,
					dsu_pmu_cpu_online,
					dsu_pmu_cpu_teardown);
	if (ret < 0)
		return ret;
	dsu_pmu_cpuhp_state = ret;
	ret = platform_driver_register(&dsu_pmu_driver);
	if (ret)
		cpuhp_remove_multi_state(dsu_pmu_cpuhp_state);

	return ret;
}

static void __exit dsu_pmu_exit(void)
{
	platform_driver_unregister(&dsu_pmu_driver);
	cpuhp_remove_multi_state(dsu_pmu_cpuhp_state);
}

module_init(dsu_pmu_init);
module_exit(dsu_pmu_exit);

MODULE_DESCRIPTION("Perf driver for ARM DynamIQ Shared Unit");
MODULE_AUTHOR("Suzuki K Poulose <suzuki.poulose@arm.com>");
MODULE_LICENSE("GPL v2");