1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ARM DMC-620 memory controller PMU driver
4 *
5 * Copyright (C) 2020 Ampere Computing LLC.
6 */
7
8#define DMC620_PMUNAME		"arm_dmc620"
9#define DMC620_DRVNAME		DMC620_PMUNAME "_pmu"
10#define pr_fmt(fmt)		DMC620_DRVNAME ": " fmt
11
12#include <linux/acpi.h>
13#include <linux/bitfield.h>
14#include <linux/bitops.h>
15#include <linux/cpuhotplug.h>
16#include <linux/cpumask.h>
17#include <linux/device.h>
18#include <linux/errno.h>
19#include <linux/interrupt.h>
20#include <linux/irq.h>
21#include <linux/kernel.h>
22#include <linux/list.h>
23#include <linux/module.h>
24#include <linux/mutex.h>
25#include <linux/perf_event.h>
26#include <linux/platform_device.h>
27#include <linux/printk.h>
28#include <linux/rculist.h>
29#include <linux/refcount.h>
30
31#define DMC620_PA_SHIFT					12
32#define DMC620_CNT_INIT					0x80000000
33#define DMC620_CNT_MAX_PERIOD				0xffffffff
34#define DMC620_PMU_CLKDIV2_MAX_COUNTERS			8
35#define DMC620_PMU_CLK_MAX_COUNTERS			2
36#define DMC620_PMU_MAX_COUNTERS				\
37	(DMC620_PMU_CLKDIV2_MAX_COUNTERS + DMC620_PMU_CLK_MAX_COUNTERS)
38
39/*
40 * The PMU registers start at 0xA00 in the DMC-620 memory map, and these
41 * offsets are relative to that base.
42 *
43 * Each counter has a group of control/value registers, and the
44 * DMC620_PMU_COUNTERn offsets are within a counter group.
45 *
46 * The counter registers groups start at 0xA10.
47 */
48#define DMC620_PMU_OVERFLOW_STATUS_CLKDIV2		0x8
49#define  DMC620_PMU_OVERFLOW_STATUS_CLKDIV2_MASK	\
50		(DMC620_PMU_CLKDIV2_MAX_COUNTERS - 1)
51#define DMC620_PMU_OVERFLOW_STATUS_CLK			0xC
52#define  DMC620_PMU_OVERFLOW_STATUS_CLK_MASK		\
53		(DMC620_PMU_CLK_MAX_COUNTERS - 1)
54#define DMC620_PMU_COUNTERS_BASE			0x10
55#define DMC620_PMU_COUNTERn_MASK_31_00			0x0
56#define DMC620_PMU_COUNTERn_MASK_63_32			0x4
57#define DMC620_PMU_COUNTERn_MATCH_31_00			0x8
58#define DMC620_PMU_COUNTERn_MATCH_63_32			0xC
59#define DMC620_PMU_COUNTERn_CONTROL			0x10
60#define  DMC620_PMU_COUNTERn_CONTROL_ENABLE		BIT(0)
61#define  DMC620_PMU_COUNTERn_CONTROL_INVERT		BIT(1)
62#define  DMC620_PMU_COUNTERn_CONTROL_EVENT_MUX		GENMASK(6, 2)
63#define  DMC620_PMU_COUNTERn_CONTROL_INCR_MUX		GENMASK(8, 7)
64#define DMC620_PMU_COUNTERn_VALUE			0x20
65/* Offset of the registers for a given counter, relative to 0xA00 */
66#define DMC620_PMU_COUNTERn_OFFSET(n) \
67	(DMC620_PMU_COUNTERS_BASE + 0x28 * (n))
68
69/*
70 * dmc620_pmu_irqs_lock: protects dmc620_pmu_irqs list
71 * dmc620_pmu_node_lock: protects pmus_node lists in all dmc620_pmu instances
72 */
73static DEFINE_MUTEX(dmc620_pmu_irqs_lock);
74static DEFINE_MUTEX(dmc620_pmu_node_lock);
75static LIST_HEAD(dmc620_pmu_irqs);
76
77struct dmc620_pmu_irq {
78	struct hlist_node node;
79	struct list_head pmus_node;
80	struct list_head irqs_node;
81	refcount_t refcount;
82	unsigned int irq_num;
83	unsigned int cpu;
84};
85
86struct dmc620_pmu {
87	struct pmu pmu;
88
89	void __iomem *base;
90	struct dmc620_pmu_irq *irq;
91	struct list_head pmus_node;
92
93	/*
94	 * We put all clkdiv2 and clk counters to a same array.
95	 * The first DMC620_PMU_CLKDIV2_MAX_COUNTERS bits belong to
96	 * clkdiv2 counters, the last DMC620_PMU_CLK_MAX_COUNTERS
97	 * belong to clk counters.
98	 */
99	DECLARE_BITMAP(used_mask, DMC620_PMU_MAX_COUNTERS);
100	struct perf_event *events[DMC620_PMU_MAX_COUNTERS];
101};
102
103#define to_dmc620_pmu(p) (container_of(p, struct dmc620_pmu, pmu))
104
105static int cpuhp_state_num;
106
107struct dmc620_pmu_event_attr {
108	struct device_attribute attr;
109	u8 clkdiv2;
110	u8 eventid;
111};
112
113static ssize_t
114dmc620_pmu_event_show(struct device *dev,
115			   struct device_attribute *attr, char *page)
116{
117	struct dmc620_pmu_event_attr *eattr;
118
119	eattr = container_of(attr, typeof(*eattr), attr);
120
121	return sysfs_emit(page, "event=0x%x,clkdiv2=0x%x\n", eattr->eventid, eattr->clkdiv2);
122}
123
124#define DMC620_PMU_EVENT_ATTR(_name, _eventid, _clkdiv2)		\
125	(&((struct dmc620_pmu_event_attr[]) {{				\
126		.attr = __ATTR(_name, 0444, dmc620_pmu_event_show, NULL),	\
127		.clkdiv2 = _clkdiv2,						\
128		.eventid = _eventid,					\
129	}})[0].attr.attr)
130
131static struct attribute *dmc620_pmu_events_attrs[] = {
132	/* clkdiv2 events list */
133	DMC620_PMU_EVENT_ATTR(clkdiv2_cycle_count, 0x0, 1),
134	DMC620_PMU_EVENT_ATTR(clkdiv2_allocate, 0x1, 1),
135	DMC620_PMU_EVENT_ATTR(clkdiv2_queue_depth, 0x2, 1),
136	DMC620_PMU_EVENT_ATTR(clkdiv2_waiting_for_wr_data, 0x3, 1),
137	DMC620_PMU_EVENT_ATTR(clkdiv2_read_backlog, 0x4, 1),
138	DMC620_PMU_EVENT_ATTR(clkdiv2_waiting_for_mi, 0x5, 1),
139	DMC620_PMU_EVENT_ATTR(clkdiv2_hazard_resolution, 0x6, 1),
140	DMC620_PMU_EVENT_ATTR(clkdiv2_enqueue, 0x7, 1),
141	DMC620_PMU_EVENT_ATTR(clkdiv2_arbitrate, 0x8, 1),
142	DMC620_PMU_EVENT_ATTR(clkdiv2_lrank_turnaround_activate, 0x9, 1),
143	DMC620_PMU_EVENT_ATTR(clkdiv2_prank_turnaround_activate, 0xa, 1),
144	DMC620_PMU_EVENT_ATTR(clkdiv2_read_depth, 0xb, 1),
145	DMC620_PMU_EVENT_ATTR(clkdiv2_write_depth, 0xc, 1),
146	DMC620_PMU_EVENT_ATTR(clkdiv2_highigh_qos_depth, 0xd, 1),
147	DMC620_PMU_EVENT_ATTR(clkdiv2_high_qos_depth, 0xe, 1),
148	DMC620_PMU_EVENT_ATTR(clkdiv2_medium_qos_depth, 0xf, 1),
149	DMC620_PMU_EVENT_ATTR(clkdiv2_low_qos_depth, 0x10, 1),
150	DMC620_PMU_EVENT_ATTR(clkdiv2_activate, 0x11, 1),
151	DMC620_PMU_EVENT_ATTR(clkdiv2_rdwr, 0x12, 1),
152	DMC620_PMU_EVENT_ATTR(clkdiv2_refresh, 0x13, 1),
153	DMC620_PMU_EVENT_ATTR(clkdiv2_training_request, 0x14, 1),
154	DMC620_PMU_EVENT_ATTR(clkdiv2_t_mac_tracker, 0x15, 1),
155	DMC620_PMU_EVENT_ATTR(clkdiv2_bk_fsm_tracker, 0x16, 1),
156	DMC620_PMU_EVENT_ATTR(clkdiv2_bk_open_tracker, 0x17, 1),
157	DMC620_PMU_EVENT_ATTR(clkdiv2_ranks_in_pwr_down, 0x18, 1),
158	DMC620_PMU_EVENT_ATTR(clkdiv2_ranks_in_sref, 0x19, 1),
159
160	/* clk events list */
161	DMC620_PMU_EVENT_ATTR(clk_cycle_count, 0x0, 0),
162	DMC620_PMU_EVENT_ATTR(clk_request, 0x1, 0),
163	DMC620_PMU_EVENT_ATTR(clk_upload_stall, 0x2, 0),
164	NULL,
165};
166
167static const struct attribute_group dmc620_pmu_events_attr_group = {
168	.name = "events",
169	.attrs = dmc620_pmu_events_attrs,
170};
171
172/* User ABI */
173#define ATTR_CFG_FLD_mask_CFG		config
174#define ATTR_CFG_FLD_mask_LO		0
175#define ATTR_CFG_FLD_mask_HI		44
176#define ATTR_CFG_FLD_match_CFG		config1
177#define ATTR_CFG_FLD_match_LO		0
178#define ATTR_CFG_FLD_match_HI		44
179#define ATTR_CFG_FLD_invert_CFG		config2
180#define ATTR_CFG_FLD_invert_LO		0
181#define ATTR_CFG_FLD_invert_HI		0
182#define ATTR_CFG_FLD_incr_CFG		config2
183#define ATTR_CFG_FLD_incr_LO		1
184#define ATTR_CFG_FLD_incr_HI		2
185#define ATTR_CFG_FLD_event_CFG		config2
186#define ATTR_CFG_FLD_event_LO		3
187#define ATTR_CFG_FLD_event_HI		8
188#define ATTR_CFG_FLD_clkdiv2_CFG	config2
189#define ATTR_CFG_FLD_clkdiv2_LO		9
190#define ATTR_CFG_FLD_clkdiv2_HI		9
191
192#define __GEN_PMU_FORMAT_ATTR(cfg, lo, hi)			\
193	(lo) == (hi) ? #cfg ":" #lo "\n" : #cfg ":" #lo "-" #hi
194
195#define _GEN_PMU_FORMAT_ATTR(cfg, lo, hi)			\
196	__GEN_PMU_FORMAT_ATTR(cfg, lo, hi)
197
198#define GEN_PMU_FORMAT_ATTR(name)				\
199	PMU_FORMAT_ATTR(name,					\
200	_GEN_PMU_FORMAT_ATTR(ATTR_CFG_FLD_##name##_CFG,		\
201			     ATTR_CFG_FLD_##name##_LO,		\
202			     ATTR_CFG_FLD_##name##_HI))
203
204#define _ATTR_CFG_GET_FLD(attr, cfg, lo, hi)			\
205	((((attr)->cfg) >> lo) & GENMASK_ULL(hi - lo, 0))
206
207#define ATTR_CFG_GET_FLD(attr, name)				\
208	_ATTR_CFG_GET_FLD(attr,					\
209			  ATTR_CFG_FLD_##name##_CFG,		\
210			  ATTR_CFG_FLD_##name##_LO,		\
211			  ATTR_CFG_FLD_##name##_HI)
212
213GEN_PMU_FORMAT_ATTR(mask);
214GEN_PMU_FORMAT_ATTR(match);
215GEN_PMU_FORMAT_ATTR(invert);
216GEN_PMU_FORMAT_ATTR(incr);
217GEN_PMU_FORMAT_ATTR(event);
218GEN_PMU_FORMAT_ATTR(clkdiv2);
219
220static struct attribute *dmc620_pmu_formats_attrs[] = {
221	&format_attr_mask.attr,
222	&format_attr_match.attr,
223	&format_attr_invert.attr,
224	&format_attr_incr.attr,
225	&format_attr_event.attr,
226	&format_attr_clkdiv2.attr,
227	NULL,
228};
229
230static const struct attribute_group dmc620_pmu_format_attr_group = {
231	.name	= "format",
232	.attrs	= dmc620_pmu_formats_attrs,
233};
234
235static ssize_t dmc620_pmu_cpumask_show(struct device *dev,
236				       struct device_attribute *attr, char *buf)
237{
238	struct dmc620_pmu *dmc620_pmu = to_dmc620_pmu(dev_get_drvdata(dev));
239
240	return cpumap_print_to_pagebuf(true, buf,
241				       cpumask_of(dmc620_pmu->irq->cpu));
242}
243
244static struct device_attribute dmc620_pmu_cpumask_attr =
245	__ATTR(cpumask, 0444, dmc620_pmu_cpumask_show, NULL);
246
247static struct attribute *dmc620_pmu_cpumask_attrs[] = {
248	&dmc620_pmu_cpumask_attr.attr,
249	NULL,
250};
251
252static const struct attribute_group dmc620_pmu_cpumask_attr_group = {
253	.attrs = dmc620_pmu_cpumask_attrs,
254};
255
256static const struct attribute_group *dmc620_pmu_attr_groups[] = {
257	&dmc620_pmu_events_attr_group,
258	&dmc620_pmu_format_attr_group,
259	&dmc620_pmu_cpumask_attr_group,
260	NULL,
261};
262
263static inline
264u32 dmc620_pmu_creg_read(struct dmc620_pmu *dmc620_pmu,
265			unsigned int idx, unsigned int reg)
266{
267	return readl(dmc620_pmu->base + DMC620_PMU_COUNTERn_OFFSET(idx) + reg);
268}
269
270static inline
271void dmc620_pmu_creg_write(struct dmc620_pmu *dmc620_pmu,
272			unsigned int idx, unsigned int reg, u32 val)
273{
274	writel(val, dmc620_pmu->base + DMC620_PMU_COUNTERn_OFFSET(idx) + reg);
275}
276
277static
278unsigned int dmc620_event_to_counter_control(struct perf_event *event)
279{
280	struct perf_event_attr *attr = &event->attr;
281	unsigned int reg = 0;
282
283	reg |= FIELD_PREP(DMC620_PMU_COUNTERn_CONTROL_INVERT,
284			ATTR_CFG_GET_FLD(attr, invert));
285	reg |= FIELD_PREP(DMC620_PMU_COUNTERn_CONTROL_EVENT_MUX,
286			ATTR_CFG_GET_FLD(attr, event));
287	reg |= FIELD_PREP(DMC620_PMU_COUNTERn_CONTROL_INCR_MUX,
288			ATTR_CFG_GET_FLD(attr, incr));
289
290	return reg;
291}
292
293static int dmc620_get_event_idx(struct perf_event *event)
294{
295	struct dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
296	int idx, start_idx, end_idx;
297
298	if (ATTR_CFG_GET_FLD(&event->attr, clkdiv2)) {
299		start_idx = 0;
300		end_idx = DMC620_PMU_CLKDIV2_MAX_COUNTERS;
301	} else {
302		start_idx = DMC620_PMU_CLKDIV2_MAX_COUNTERS;
303		end_idx = DMC620_PMU_MAX_COUNTERS;
304	}
305
306	for (idx = start_idx; idx < end_idx; ++idx) {
307		if (!test_and_set_bit(idx, dmc620_pmu->used_mask))
308			return idx;
309	}
310
311	/* The counters are all in use. */
312	return -EAGAIN;
313}
314
315static inline
316u64 dmc620_pmu_read_counter(struct perf_event *event)
317{
318	struct dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
319
320	return dmc620_pmu_creg_read(dmc620_pmu,
321				    event->hw.idx, DMC620_PMU_COUNTERn_VALUE);
322}
323
324static void dmc620_pmu_event_update(struct perf_event *event)
325{
326	struct hw_perf_event *hwc = &event->hw;
327	u64 delta, prev_count, new_count;
328
329	do {
330		/* We may also be called from the irq handler */
331		prev_count = local64_read(&hwc->prev_count);
332		new_count = dmc620_pmu_read_counter(event);
333	} while (local64_cmpxchg(&hwc->prev_count,
334			prev_count, new_count) != prev_count);
335	delta = (new_count - prev_count) & DMC620_CNT_MAX_PERIOD;
336	local64_add(delta, &event->count);
337}
338
339static void dmc620_pmu_event_set_period(struct perf_event *event)
340{
341	struct dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
342
343	local64_set(&event->hw.prev_count, DMC620_CNT_INIT);
344	dmc620_pmu_creg_write(dmc620_pmu,
345			      event->hw.idx, DMC620_PMU_COUNTERn_VALUE, DMC620_CNT_INIT);
346}
347
348static void dmc620_pmu_enable_counter(struct perf_event *event)
349{
350	struct dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
351	u32 reg;
352
353	reg = dmc620_event_to_counter_control(event) | DMC620_PMU_COUNTERn_CONTROL_ENABLE;
354	dmc620_pmu_creg_write(dmc620_pmu,
355			      event->hw.idx, DMC620_PMU_COUNTERn_CONTROL, reg);
356}
357
358static void dmc620_pmu_disable_counter(struct perf_event *event)
359{
360	struct dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
361
362	dmc620_pmu_creg_write(dmc620_pmu,
363			      event->hw.idx, DMC620_PMU_COUNTERn_CONTROL, 0);
364}
365
366static irqreturn_t dmc620_pmu_handle_irq(int irq_num, void *data)
367{
368	struct dmc620_pmu_irq *irq = data;
369	struct dmc620_pmu *dmc620_pmu;
370	irqreturn_t ret = IRQ_NONE;
371
372	rcu_read_lock();
373	list_for_each_entry_rcu(dmc620_pmu, &irq->pmus_node, pmus_node) {
374		unsigned long status;
375		struct perf_event *event;
376		unsigned int idx;
377
378		/*
379		 * HW doesn't provide a control to atomically disable all counters.
380		 * To prevent race condition (overflow happens while clearing status register),
381		 * disable all events before continuing
382		 */
383		for (idx = 0; idx < DMC620_PMU_MAX_COUNTERS; idx++) {
384			event = dmc620_pmu->events[idx];
385			if (!event)
386				continue;
387			dmc620_pmu_disable_counter(event);
388		}
389
390		status = readl(dmc620_pmu->base + DMC620_PMU_OVERFLOW_STATUS_CLKDIV2);
391		status |= (readl(dmc620_pmu->base + DMC620_PMU_OVERFLOW_STATUS_CLK) <<
392				DMC620_PMU_CLKDIV2_MAX_COUNTERS);
393		if (status) {
394			for_each_set_bit(idx, &status,
395					DMC620_PMU_MAX_COUNTERS) {
396				event = dmc620_pmu->events[idx];
397				if (WARN_ON_ONCE(!event))
398					continue;
399				dmc620_pmu_event_update(event);
400				dmc620_pmu_event_set_period(event);
401			}
402
403			if (status & DMC620_PMU_OVERFLOW_STATUS_CLKDIV2_MASK)
404				writel(0, dmc620_pmu->base + DMC620_PMU_OVERFLOW_STATUS_CLKDIV2);
405
406			if ((status >> DMC620_PMU_CLKDIV2_MAX_COUNTERS) &
407				DMC620_PMU_OVERFLOW_STATUS_CLK_MASK)
408				writel(0, dmc620_pmu->base + DMC620_PMU_OVERFLOW_STATUS_CLK);
409		}
410
411		for (idx = 0; idx < DMC620_PMU_MAX_COUNTERS; idx++) {
412			event = dmc620_pmu->events[idx];
413			if (!event)
414				continue;
415			if (!(event->hw.state & PERF_HES_STOPPED))
416				dmc620_pmu_enable_counter(event);
417		}
418
419		ret = IRQ_HANDLED;
420	}
421	rcu_read_unlock();
422
423	return ret;
424}
425
426static struct dmc620_pmu_irq *__dmc620_pmu_get_irq(int irq_num)
427{
428	struct dmc620_pmu_irq *irq;
429	int ret;
430
431	list_for_each_entry(irq, &dmc620_pmu_irqs, irqs_node)
432		if (irq->irq_num == irq_num && refcount_inc_not_zero(&irq->refcount))
433			return irq;
434
435	irq = kzalloc(sizeof(*irq), GFP_KERNEL);
436	if (!irq)
437		return ERR_PTR(-ENOMEM);
438
439	INIT_LIST_HEAD(&irq->pmus_node);
440
441	/* Pick one CPU to be the preferred one to use */
442	irq->cpu = raw_smp_processor_id();
443	refcount_set(&irq->refcount, 1);
444
445	ret = request_irq(irq_num, dmc620_pmu_handle_irq,
446			  IRQF_NOBALANCING | IRQF_NO_THREAD,
447			  "dmc620-pmu", irq);
448	if (ret)
449		goto out_free_aff;
450
451	ret = irq_set_affinity(irq_num, cpumask_of(irq->cpu));
452	if (ret)
453		goto out_free_irq;
454
455	ret = cpuhp_state_add_instance_nocalls(cpuhp_state_num, &irq->node);
456	if (ret)
457		goto out_free_irq;
458
459	irq->irq_num = irq_num;
460	list_add(&irq->irqs_node, &dmc620_pmu_irqs);
461
462	return irq;
463
464out_free_irq:
465	free_irq(irq_num, irq);
466out_free_aff:
467	kfree(irq);
468	return ERR_PTR(ret);
469}
470
471static int dmc620_pmu_get_irq(struct dmc620_pmu *dmc620_pmu, int irq_num)
472{
473	struct dmc620_pmu_irq *irq;
474
475	mutex_lock(&dmc620_pmu_irqs_lock);
476	irq = __dmc620_pmu_get_irq(irq_num);
477	mutex_unlock(&dmc620_pmu_irqs_lock);
478
479	if (IS_ERR(irq))
480		return PTR_ERR(irq);
481
482	dmc620_pmu->irq = irq;
483	mutex_lock(&dmc620_pmu_node_lock);
484	list_add_rcu(&dmc620_pmu->pmus_node, &irq->pmus_node);
485	mutex_unlock(&dmc620_pmu_node_lock);
486
487	return 0;
488}
489
490static void dmc620_pmu_put_irq(struct dmc620_pmu *dmc620_pmu)
491{
492	struct dmc620_pmu_irq *irq = dmc620_pmu->irq;
493
494	mutex_lock(&dmc620_pmu_node_lock);
495	list_del_rcu(&dmc620_pmu->pmus_node);
496	mutex_unlock(&dmc620_pmu_node_lock);
497
498	mutex_lock(&dmc620_pmu_irqs_lock);
499	if (!refcount_dec_and_test(&irq->refcount)) {
500		mutex_unlock(&dmc620_pmu_irqs_lock);
501		return;
502	}
503
504	list_del(&irq->irqs_node);
505	mutex_unlock(&dmc620_pmu_irqs_lock);
506
507	free_irq(irq->irq_num, irq);
508	cpuhp_state_remove_instance_nocalls(cpuhp_state_num, &irq->node);
509	kfree(irq);
510}
511
512static int dmc620_pmu_event_init(struct perf_event *event)
513{
514	struct dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
515	struct hw_perf_event *hwc = &event->hw;
516	struct perf_event *sibling;
517
518	if (event->attr.type != event->pmu->type)
519		return -ENOENT;
520
521	/*
522	 * DMC 620 PMUs are shared across all cpus and cannot
523	 * support task bound and sampling events.
524	 */
525	if (is_sampling_event(event) ||
526		event->attach_state & PERF_ATTACH_TASK) {
527		dev_dbg(dmc620_pmu->pmu.dev,
528			"Can't support per-task counters\n");
529		return -EOPNOTSUPP;
530	}
531
532	/*
533	 * Many perf core operations (eg. events rotation) operate on a
534	 * single CPU context. This is obvious for CPU PMUs, where one
535	 * expects the same sets of events being observed on all CPUs,
536	 * but can lead to issues for off-core PMUs, where each
537	 * event could be theoretically assigned to a different CPU. To
538	 * mitigate this, we enforce CPU assignment to one, selected
539	 * processor.
540	 */
541	event->cpu = dmc620_pmu->irq->cpu;
542	if (event->cpu < 0)
543		return -EINVAL;
544
545	/*
546	 * We can't atomically disable all HW counters so only one event allowed,
547	 * although software events are acceptable.
548	 */
549	if (event->group_leader != event &&
550			!is_software_event(event->group_leader))
551		return -EINVAL;
552
553	for_each_sibling_event(sibling, event->group_leader) {
554		if (sibling != event &&
555				!is_software_event(sibling))
556			return -EINVAL;
557	}
558
559	hwc->idx = -1;
560	return 0;
561}
562
563static void dmc620_pmu_read(struct perf_event *event)
564{
565	dmc620_pmu_event_update(event);
566}
567
568static void dmc620_pmu_start(struct perf_event *event, int flags)
569{
570	event->hw.state = 0;
571	dmc620_pmu_event_set_period(event);
572	dmc620_pmu_enable_counter(event);
573}
574
575static void dmc620_pmu_stop(struct perf_event *event, int flags)
576{
577	if (event->hw.state & PERF_HES_STOPPED)
578		return;
579
580	dmc620_pmu_disable_counter(event);
581	dmc620_pmu_event_update(event);
582	event->hw.state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
583}
584
585static int dmc620_pmu_add(struct perf_event *event, int flags)
586{
587	struct dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
588	struct perf_event_attr *attr = &event->attr;
589	struct hw_perf_event *hwc = &event->hw;
590	int idx;
591	u64 reg;
592
593	idx = dmc620_get_event_idx(event);
594	if (idx < 0)
595		return idx;
596
597	hwc->idx = idx;
598	dmc620_pmu->events[idx] = event;
599	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
600
601	reg = ATTR_CFG_GET_FLD(attr, mask);
602	dmc620_pmu_creg_write(dmc620_pmu,
603			      idx, DMC620_PMU_COUNTERn_MASK_31_00, lower_32_bits(reg));
604	dmc620_pmu_creg_write(dmc620_pmu,
605			      idx, DMC620_PMU_COUNTERn_MASK_63_32, upper_32_bits(reg));
606
607	reg = ATTR_CFG_GET_FLD(attr, match);
608	dmc620_pmu_creg_write(dmc620_pmu,
609			      idx, DMC620_PMU_COUNTERn_MATCH_31_00, lower_32_bits(reg));
610	dmc620_pmu_creg_write(dmc620_pmu,
611			      idx, DMC620_PMU_COUNTERn_MATCH_63_32, upper_32_bits(reg));
612
613	if (flags & PERF_EF_START)
614		dmc620_pmu_start(event, PERF_EF_RELOAD);
615
616	perf_event_update_userpage(event);
617	return 0;
618}
619
620static void dmc620_pmu_del(struct perf_event *event, int flags)
621{
622	struct dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
623	struct hw_perf_event *hwc = &event->hw;
624	int idx = hwc->idx;
625
626	dmc620_pmu_stop(event, PERF_EF_UPDATE);
627	dmc620_pmu->events[idx] = NULL;
628	clear_bit(idx, dmc620_pmu->used_mask);
629	perf_event_update_userpage(event);
630}
631
632static int dmc620_pmu_cpu_teardown(unsigned int cpu,
633				   struct hlist_node *node)
634{
635	struct dmc620_pmu_irq *irq;
636	struct dmc620_pmu *dmc620_pmu;
637	unsigned int target;
638
639	irq = hlist_entry_safe(node, struct dmc620_pmu_irq, node);
640	if (cpu != irq->cpu)
641		return 0;
642
643	target = cpumask_any_but(cpu_online_mask, cpu);
644	if (target >= nr_cpu_ids)
645		return 0;
646
647	/* We're only reading, but this isn't the place to be involving RCU */
648	mutex_lock(&dmc620_pmu_node_lock);
649	list_for_each_entry(dmc620_pmu, &irq->pmus_node, pmus_node)
650		perf_pmu_migrate_context(&dmc620_pmu->pmu, irq->cpu, target);
651	mutex_unlock(&dmc620_pmu_node_lock);
652
653	WARN_ON(irq_set_affinity(irq->irq_num, cpumask_of(target)));
654	irq->cpu = target;
655
656	return 0;
657}
658
659static int dmc620_pmu_device_probe(struct platform_device *pdev)
660{
661	struct dmc620_pmu *dmc620_pmu;
662	struct resource *res;
663	char *name;
664	int irq_num;
665	int i, ret;
666
667	dmc620_pmu = devm_kzalloc(&pdev->dev,
668			sizeof(struct dmc620_pmu), GFP_KERNEL);
669	if (!dmc620_pmu)
670		return -ENOMEM;
671
672	platform_set_drvdata(pdev, dmc620_pmu);
673
674	dmc620_pmu->pmu = (struct pmu) {
675		.module = THIS_MODULE,
676		.capabilities	= PERF_PMU_CAP_NO_EXCLUDE,
677		.task_ctx_nr	= perf_invalid_context,
678		.event_init	= dmc620_pmu_event_init,
679		.add		= dmc620_pmu_add,
680		.del		= dmc620_pmu_del,
681		.start		= dmc620_pmu_start,
682		.stop		= dmc620_pmu_stop,
683		.read		= dmc620_pmu_read,
684		.attr_groups	= dmc620_pmu_attr_groups,
685	};
686
687	dmc620_pmu->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
688	if (IS_ERR(dmc620_pmu->base))
689		return PTR_ERR(dmc620_pmu->base);
690
691	/* Make sure device is reset before enabling interrupt */
692	for (i = 0; i < DMC620_PMU_MAX_COUNTERS; i++)
693		dmc620_pmu_creg_write(dmc620_pmu, i, DMC620_PMU_COUNTERn_CONTROL, 0);
694	writel(0, dmc620_pmu->base + DMC620_PMU_OVERFLOW_STATUS_CLKDIV2);
695	writel(0, dmc620_pmu->base + DMC620_PMU_OVERFLOW_STATUS_CLK);
696
697	irq_num = platform_get_irq(pdev, 0);
698	if (irq_num < 0)
699		return irq_num;
700
701	ret = dmc620_pmu_get_irq(dmc620_pmu, irq_num);
702	if (ret)
703		return ret;
704
705	name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
706				  "%s_%llx", DMC620_PMUNAME,
707				  (u64)(res->start >> DMC620_PA_SHIFT));
708	if (!name) {
709		dev_err(&pdev->dev,
710			  "Create name failed, PMU @%pa\n", &res->start);
711		ret = -ENOMEM;
712		goto out_teardown_dev;
713	}
714
715	ret = perf_pmu_register(&dmc620_pmu->pmu, name, -1);
716	if (ret)
717		goto out_teardown_dev;
718
719	return 0;
720
721out_teardown_dev:
722	dmc620_pmu_put_irq(dmc620_pmu);
723	synchronize_rcu();
724	return ret;
725}
726
727static void dmc620_pmu_device_remove(struct platform_device *pdev)
728{
729	struct dmc620_pmu *dmc620_pmu = platform_get_drvdata(pdev);
730
731	dmc620_pmu_put_irq(dmc620_pmu);
732
733	/* perf will synchronise RCU before devres can free dmc620_pmu */
734	perf_pmu_unregister(&dmc620_pmu->pmu);
735}
736
737static const struct acpi_device_id dmc620_acpi_match[] = {
738	{ "ARMHD620", 0},
739	{},
740};
741MODULE_DEVICE_TABLE(acpi, dmc620_acpi_match);
742static struct platform_driver dmc620_pmu_driver = {
743	.driver	= {
744		.name		= DMC620_DRVNAME,
745		.acpi_match_table = dmc620_acpi_match,
746		.suppress_bind_attrs = true,
747	},
748	.probe	= dmc620_pmu_device_probe,
749	.remove_new = dmc620_pmu_device_remove,
750};
751
752static int __init dmc620_pmu_init(void)
753{
754	int ret;
755
756	cpuhp_state_num = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
757				      DMC620_DRVNAME,
758				      NULL,
759				      dmc620_pmu_cpu_teardown);
760	if (cpuhp_state_num < 0)
761		return cpuhp_state_num;
762
763	ret = platform_driver_register(&dmc620_pmu_driver);
764	if (ret)
765		cpuhp_remove_multi_state(cpuhp_state_num);
766
767	return ret;
768}
769
770static void __exit dmc620_pmu_exit(void)
771{
772	platform_driver_unregister(&dmc620_pmu_driver);
773	cpuhp_remove_multi_state(cpuhp_state_num);
774}
775
776module_init(dmc620_pmu_init);
777module_exit(dmc620_pmu_exit);
778
779MODULE_DESCRIPTION("Perf driver for the ARM DMC-620 memory controller");
780MODULE_AUTHOR("Tuan Phan <tuanphan@os.amperecomputing.com");
781MODULE_LICENSE("GPL v2");
782