xref: /openbmc/linux/drivers/perf/qcom_l3_pmu.c (revision 1a59d1b8)
1 /*
2  * Driver for the L3 cache PMUs in Qualcomm Technologies chips.
3  *
4  * The driver supports a distributed cache architecture where the overall
5  * cache for a socket is comprised of multiple slices each with its own PMU.
6  * Access to each individual PMU is provided even though all CPUs share all
7  * the slices. User space needs to aggregate to individual counts to provide
8  * a global picture.
9  *
10  * See Documentation/perf/qcom_l3_pmu.txt for more details.
11  *
12  * Copyright (c) 2015-2017, The Linux Foundation. All rights reserved.
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License version 2 and
16  * only version 2 as published by the Free Software Foundation.
17  *
18  * This program is distributed in the hope that it will be useful,
19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21  * GNU General Public License for more details.
22  */
23 
24 #include <linux/acpi.h>
25 #include <linux/bitops.h>
26 #include <linux/interrupt.h>
27 #include <linux/io.h>
28 #include <linux/list.h>
29 #include <linux/module.h>
30 #include <linux/perf_event.h>
31 #include <linux/platform_device.h>
32 
33 /*
34  * General constants
35  */
36 
37 /* Number of counters on each PMU */
38 #define L3_NUM_COUNTERS  8
39 /* Mask for the event type field within perf_event_attr.config and EVTYPE reg */
40 #define L3_EVTYPE_MASK   0xFF
41 /*
42  * Bit position of the 'long counter' flag within perf_event_attr.config.
43  * Reserve some space between the event type and this flag to allow expansion
44  * in the event type field.
45  */
46 #define L3_EVENT_LC_BIT  32
47 
48 /*
49  * Register offsets
50  */
51 
52 /* Perfmon registers */
53 #define L3_HML3_PM_CR       0x000
54 #define L3_HML3_PM_EVCNTR(__cntr) (0x420 + ((__cntr) & 0x7) * 8)
55 #define L3_HML3_PM_CNTCTL(__cntr) (0x120 + ((__cntr) & 0x7) * 8)
56 #define L3_HML3_PM_EVTYPE(__cntr) (0x220 + ((__cntr) & 0x7) * 8)
57 #define L3_HML3_PM_FILTRA   0x300
58 #define L3_HML3_PM_FILTRB   0x308
59 #define L3_HML3_PM_FILTRC   0x310
60 #define L3_HML3_PM_FILTRAM  0x304
61 #define L3_HML3_PM_FILTRBM  0x30C
62 #define L3_HML3_PM_FILTRCM  0x314
63 
64 /* Basic counter registers */
65 #define L3_M_BC_CR         0x500
66 #define L3_M_BC_SATROLL_CR 0x504
67 #define L3_M_BC_CNTENSET   0x508
68 #define L3_M_BC_CNTENCLR   0x50C
69 #define L3_M_BC_INTENSET   0x510
70 #define L3_M_BC_INTENCLR   0x514
71 #define L3_M_BC_GANG       0x718
72 #define L3_M_BC_OVSR       0x740
73 #define L3_M_BC_IRQCTL     0x96C
74 
75 /*
76  * Bit field definitions
77  */
78 
79 /* L3_HML3_PM_CR */
80 #define PM_CR_RESET           (0)
81 
82 /* L3_HML3_PM_XCNTCTL/L3_HML3_PM_CNTCTLx */
83 #define PMCNT_RESET           (0)
84 
85 /* L3_HML3_PM_EVTYPEx */
86 #define EVSEL(__val)          ((__val) & L3_EVTYPE_MASK)
87 
88 /* Reset value for all the filter registers */
89 #define PM_FLTR_RESET         (0)
90 
91 /* L3_M_BC_CR */
92 #define BC_RESET              (1UL << 1)
93 #define BC_ENABLE             (1UL << 0)
94 
95 /* L3_M_BC_SATROLL_CR */
96 #define BC_SATROLL_CR_RESET   (0)
97 
98 /* L3_M_BC_CNTENSET */
99 #define PMCNTENSET(__cntr)    (1UL << ((__cntr) & 0x7))
100 
101 /* L3_M_BC_CNTENCLR */
102 #define PMCNTENCLR(__cntr)    (1UL << ((__cntr) & 0x7))
103 #define BC_CNTENCLR_RESET     (0xFF)
104 
105 /* L3_M_BC_INTENSET */
106 #define PMINTENSET(__cntr)    (1UL << ((__cntr) & 0x7))
107 
108 /* L3_M_BC_INTENCLR */
109 #define PMINTENCLR(__cntr)    (1UL << ((__cntr) & 0x7))
110 #define BC_INTENCLR_RESET     (0xFF)
111 
112 /* L3_M_BC_GANG */
113 #define GANG_EN(__cntr)       (1UL << ((__cntr) & 0x7))
114 #define BC_GANG_RESET         (0)
115 
116 /* L3_M_BC_OVSR */
117 #define PMOVSRCLR(__cntr)     (1UL << ((__cntr) & 0x7))
118 #define PMOVSRCLR_RESET       (0xFF)
119 
120 /* L3_M_BC_IRQCTL */
121 #define PMIRQONMSBEN(__cntr)  (1UL << ((__cntr) & 0x7))
122 #define BC_IRQCTL_RESET       (0x0)
123 
124 /*
125  * Events
126  */
127 
128 #define L3_EVENT_CYCLES		0x01
129 #define L3_EVENT_READ_HIT		0x20
130 #define L3_EVENT_READ_MISS		0x21
131 #define L3_EVENT_READ_HIT_D		0x22
132 #define L3_EVENT_READ_MISS_D		0x23
133 #define L3_EVENT_WRITE_HIT		0x24
134 #define L3_EVENT_WRITE_MISS		0x25
135 
136 /*
137  * Decoding of settings from perf_event_attr
138  *
139  * The config format for perf events is:
140  * - config: bits 0-7: event type
141  *           bit  32:  HW counter size requested, 0: 32 bits, 1: 64 bits
142  */
143 
144 static inline u32 get_event_type(struct perf_event *event)
145 {
146 	return (event->attr.config) & L3_EVTYPE_MASK;
147 }
148 
149 static inline bool event_uses_long_counter(struct perf_event *event)
150 {
151 	return !!(event->attr.config & BIT_ULL(L3_EVENT_LC_BIT));
152 }
153 
154 static inline int event_num_counters(struct perf_event *event)
155 {
156 	return event_uses_long_counter(event) ? 2 : 1;
157 }
158 
159 /*
160  * Main PMU, inherits from the core perf PMU type
161  */
162 struct l3cache_pmu {
163 	struct pmu		pmu;
164 	struct hlist_node	node;
165 	void __iomem		*regs;
166 	struct perf_event	*events[L3_NUM_COUNTERS];
167 	unsigned long		used_mask[BITS_TO_LONGS(L3_NUM_COUNTERS)];
168 	cpumask_t		cpumask;
169 };
170 
171 #define to_l3cache_pmu(p) (container_of(p, struct l3cache_pmu, pmu))
172 
173 /*
174  * Type used to group hardware counter operations
175  *
176  * Used to implement two types of hardware counters, standard (32bits) and
177  * long (64bits). The hardware supports counter chaining which we use to
178  * implement long counters. This support is exposed via the 'lc' flag field
179  * in perf_event_attr.config.
180  */
181 struct l3cache_event_ops {
182 	/* Called to start event monitoring */
183 	void (*start)(struct perf_event *event);
184 	/* Called to stop event monitoring */
185 	void (*stop)(struct perf_event *event, int flags);
186 	/* Called to update the perf_event */
187 	void (*update)(struct perf_event *event);
188 };
189 
190 /*
191  * Implementation of long counter operations
192  *
193  * 64bit counters are implemented by chaining two of the 32bit physical
194  * counters. The PMU only supports chaining of adjacent even/odd pairs
195  * and for simplicity the driver always configures the odd counter to
196  * count the overflows of the lower-numbered even counter. Note that since
197  * the resulting hardware counter is 64bits no IRQs are required to maintain
198  * the software counter which is also 64bits.
199  */
200 
201 static void qcom_l3_cache__64bit_counter_start(struct perf_event *event)
202 {
203 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(event->pmu);
204 	int idx = event->hw.idx;
205 	u32 evsel = get_event_type(event);
206 	u32 gang;
207 
208 	/* Set the odd counter to count the overflows of the even counter */
209 	gang = readl_relaxed(l3pmu->regs + L3_M_BC_GANG);
210 	gang |= GANG_EN(idx + 1);
211 	writel_relaxed(gang, l3pmu->regs + L3_M_BC_GANG);
212 
213 	/* Initialize the hardware counters and reset prev_count*/
214 	local64_set(&event->hw.prev_count, 0);
215 	writel_relaxed(0, l3pmu->regs + L3_HML3_PM_EVCNTR(idx + 1));
216 	writel_relaxed(0, l3pmu->regs + L3_HML3_PM_EVCNTR(idx));
217 
218 	/*
219 	 * Set the event types, the upper half must use zero and the lower
220 	 * half the actual event type
221 	 */
222 	writel_relaxed(EVSEL(0), l3pmu->regs + L3_HML3_PM_EVTYPE(idx + 1));
223 	writel_relaxed(EVSEL(evsel), l3pmu->regs + L3_HML3_PM_EVTYPE(idx));
224 
225 	/* Finally, enable the counters */
226 	writel_relaxed(PMCNT_RESET, l3pmu->regs + L3_HML3_PM_CNTCTL(idx + 1));
227 	writel_relaxed(PMCNTENSET(idx + 1), l3pmu->regs + L3_M_BC_CNTENSET);
228 	writel_relaxed(PMCNT_RESET, l3pmu->regs + L3_HML3_PM_CNTCTL(idx));
229 	writel_relaxed(PMCNTENSET(idx), l3pmu->regs + L3_M_BC_CNTENSET);
230 }
231 
232 static void qcom_l3_cache__64bit_counter_stop(struct perf_event *event,
233 					      int flags)
234 {
235 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(event->pmu);
236 	int idx = event->hw.idx;
237 	u32 gang = readl_relaxed(l3pmu->regs + L3_M_BC_GANG);
238 
239 	/* Disable the counters */
240 	writel_relaxed(PMCNTENCLR(idx), l3pmu->regs + L3_M_BC_CNTENCLR);
241 	writel_relaxed(PMCNTENCLR(idx + 1), l3pmu->regs + L3_M_BC_CNTENCLR);
242 
243 	/* Disable chaining */
244 	writel_relaxed(gang & ~GANG_EN(idx + 1), l3pmu->regs + L3_M_BC_GANG);
245 }
246 
247 static void qcom_l3_cache__64bit_counter_update(struct perf_event *event)
248 {
249 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(event->pmu);
250 	int idx = event->hw.idx;
251 	u32 hi, lo;
252 	u64 prev, new;
253 
254 	do {
255 		prev = local64_read(&event->hw.prev_count);
256 		do {
257 			hi = readl_relaxed(l3pmu->regs + L3_HML3_PM_EVCNTR(idx + 1));
258 			lo = readl_relaxed(l3pmu->regs + L3_HML3_PM_EVCNTR(idx));
259 		} while (hi != readl_relaxed(l3pmu->regs + L3_HML3_PM_EVCNTR(idx + 1)));
260 		new = ((u64)hi << 32) | lo;
261 	} while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev);
262 
263 	local64_add(new - prev, &event->count);
264 }
265 
266 static const struct l3cache_event_ops event_ops_long = {
267 	.start = qcom_l3_cache__64bit_counter_start,
268 	.stop = qcom_l3_cache__64bit_counter_stop,
269 	.update = qcom_l3_cache__64bit_counter_update,
270 };
271 
272 /*
273  * Implementation of standard counter operations
274  *
275  * 32bit counters use a single physical counter and a hardware feature that
276  * asserts the overflow IRQ on the toggling of the most significant bit in
277  * the counter. This feature allows the counters to be left free-running
278  * without needing the usual reprogramming required to properly handle races
279  * during concurrent calls to update.
280  */
281 
282 static void qcom_l3_cache__32bit_counter_start(struct perf_event *event)
283 {
284 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(event->pmu);
285 	int idx = event->hw.idx;
286 	u32 evsel = get_event_type(event);
287 	u32 irqctl = readl_relaxed(l3pmu->regs + L3_M_BC_IRQCTL);
288 
289 	/* Set the counter to assert the overflow IRQ on MSB toggling */
290 	writel_relaxed(irqctl | PMIRQONMSBEN(idx), l3pmu->regs + L3_M_BC_IRQCTL);
291 
292 	/* Initialize the hardware counter and reset prev_count*/
293 	local64_set(&event->hw.prev_count, 0);
294 	writel_relaxed(0, l3pmu->regs + L3_HML3_PM_EVCNTR(idx));
295 
296 	/* Set the event type */
297 	writel_relaxed(EVSEL(evsel), l3pmu->regs + L3_HML3_PM_EVTYPE(idx));
298 
299 	/* Enable interrupt generation by this counter */
300 	writel_relaxed(PMINTENSET(idx), l3pmu->regs + L3_M_BC_INTENSET);
301 
302 	/* Finally, enable the counter */
303 	writel_relaxed(PMCNT_RESET, l3pmu->regs + L3_HML3_PM_CNTCTL(idx));
304 	writel_relaxed(PMCNTENSET(idx), l3pmu->regs + L3_M_BC_CNTENSET);
305 }
306 
307 static void qcom_l3_cache__32bit_counter_stop(struct perf_event *event,
308 					      int flags)
309 {
310 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(event->pmu);
311 	int idx = event->hw.idx;
312 	u32 irqctl = readl_relaxed(l3pmu->regs + L3_M_BC_IRQCTL);
313 
314 	/* Disable the counter */
315 	writel_relaxed(PMCNTENCLR(idx), l3pmu->regs + L3_M_BC_CNTENCLR);
316 
317 	/* Disable interrupt generation by this counter */
318 	writel_relaxed(PMINTENCLR(idx), l3pmu->regs + L3_M_BC_INTENCLR);
319 
320 	/* Set the counter to not assert the overflow IRQ on MSB toggling */
321 	writel_relaxed(irqctl & ~PMIRQONMSBEN(idx), l3pmu->regs + L3_M_BC_IRQCTL);
322 }
323 
324 static void qcom_l3_cache__32bit_counter_update(struct perf_event *event)
325 {
326 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(event->pmu);
327 	int idx = event->hw.idx;
328 	u32 prev, new;
329 
330 	do {
331 		prev = local64_read(&event->hw.prev_count);
332 		new = readl_relaxed(l3pmu->regs + L3_HML3_PM_EVCNTR(idx));
333 	} while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev);
334 
335 	local64_add(new - prev, &event->count);
336 }
337 
338 static const struct l3cache_event_ops event_ops_std = {
339 	.start = qcom_l3_cache__32bit_counter_start,
340 	.stop = qcom_l3_cache__32bit_counter_stop,
341 	.update = qcom_l3_cache__32bit_counter_update,
342 };
343 
344 /* Retrieve the appropriate operations for the given event */
345 static
346 const struct l3cache_event_ops *l3cache_event_get_ops(struct perf_event *event)
347 {
348 	if (event_uses_long_counter(event))
349 		return &event_ops_long;
350 	else
351 		return &event_ops_std;
352 }
353 
354 /*
355  * Top level PMU functions.
356  */
357 
358 static inline void qcom_l3_cache__init(struct l3cache_pmu *l3pmu)
359 {
360 	int i;
361 
362 	writel_relaxed(BC_RESET, l3pmu->regs + L3_M_BC_CR);
363 
364 	/*
365 	 * Use writel for the first programming command to ensure the basic
366 	 * counter unit is stopped before proceeding
367 	 */
368 	writel(BC_SATROLL_CR_RESET, l3pmu->regs + L3_M_BC_SATROLL_CR);
369 
370 	writel_relaxed(BC_CNTENCLR_RESET, l3pmu->regs + L3_M_BC_CNTENCLR);
371 	writel_relaxed(BC_INTENCLR_RESET, l3pmu->regs + L3_M_BC_INTENCLR);
372 	writel_relaxed(PMOVSRCLR_RESET, l3pmu->regs + L3_M_BC_OVSR);
373 	writel_relaxed(BC_GANG_RESET, l3pmu->regs + L3_M_BC_GANG);
374 	writel_relaxed(BC_IRQCTL_RESET, l3pmu->regs + L3_M_BC_IRQCTL);
375 	writel_relaxed(PM_CR_RESET, l3pmu->regs + L3_HML3_PM_CR);
376 
377 	for (i = 0; i < L3_NUM_COUNTERS; ++i) {
378 		writel_relaxed(PMCNT_RESET, l3pmu->regs + L3_HML3_PM_CNTCTL(i));
379 		writel_relaxed(EVSEL(0), l3pmu->regs + L3_HML3_PM_EVTYPE(i));
380 	}
381 
382 	writel_relaxed(PM_FLTR_RESET, l3pmu->regs + L3_HML3_PM_FILTRA);
383 	writel_relaxed(PM_FLTR_RESET, l3pmu->regs + L3_HML3_PM_FILTRAM);
384 	writel_relaxed(PM_FLTR_RESET, l3pmu->regs + L3_HML3_PM_FILTRB);
385 	writel_relaxed(PM_FLTR_RESET, l3pmu->regs + L3_HML3_PM_FILTRBM);
386 	writel_relaxed(PM_FLTR_RESET, l3pmu->regs + L3_HML3_PM_FILTRC);
387 	writel_relaxed(PM_FLTR_RESET, l3pmu->regs + L3_HML3_PM_FILTRCM);
388 
389 	/*
390 	 * Use writel here to ensure all programming commands are done
391 	 *  before proceeding
392 	 */
393 	writel(BC_ENABLE, l3pmu->regs + L3_M_BC_CR);
394 }
395 
396 static irqreturn_t qcom_l3_cache__handle_irq(int irq_num, void *data)
397 {
398 	struct l3cache_pmu *l3pmu = data;
399 	/* Read the overflow status register */
400 	long status = readl_relaxed(l3pmu->regs + L3_M_BC_OVSR);
401 	int idx;
402 
403 	if (status == 0)
404 		return IRQ_NONE;
405 
406 	/* Clear the bits we read on the overflow status register */
407 	writel_relaxed(status, l3pmu->regs + L3_M_BC_OVSR);
408 
409 	for_each_set_bit(idx, &status, L3_NUM_COUNTERS) {
410 		struct perf_event *event;
411 		const struct l3cache_event_ops *ops;
412 
413 		event = l3pmu->events[idx];
414 		if (!event)
415 			continue;
416 
417 		/*
418 		 * Since the IRQ is not enabled for events using long counters
419 		 * we should never see one of those here, however, be consistent
420 		 * and use the ops indirections like in the other operations.
421 		 */
422 
423 		ops = l3cache_event_get_ops(event);
424 		ops->update(event);
425 	}
426 
427 	return IRQ_HANDLED;
428 }
429 
430 /*
431  * Implementation of abstract pmu functionality required by
432  * the core perf events code.
433  */
434 
435 static void qcom_l3_cache__pmu_enable(struct pmu *pmu)
436 {
437 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(pmu);
438 
439 	/* Ensure the other programming commands are observed before enabling */
440 	wmb();
441 
442 	writel_relaxed(BC_ENABLE, l3pmu->regs + L3_M_BC_CR);
443 }
444 
445 static void qcom_l3_cache__pmu_disable(struct pmu *pmu)
446 {
447 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(pmu);
448 
449 	writel_relaxed(0, l3pmu->regs + L3_M_BC_CR);
450 
451 	/* Ensure the basic counter unit is stopped before proceeding */
452 	wmb();
453 }
454 
455 /*
456  * We must NOT create groups containing events from multiple hardware PMUs,
457  * although mixing different software and hardware PMUs is allowed.
458  */
459 static bool qcom_l3_cache__validate_event_group(struct perf_event *event)
460 {
461 	struct perf_event *leader = event->group_leader;
462 	struct perf_event *sibling;
463 	int counters = 0;
464 
465 	if (leader->pmu != event->pmu && !is_software_event(leader))
466 		return false;
467 
468 	counters = event_num_counters(event);
469 	counters += event_num_counters(leader);
470 
471 	for_each_sibling_event(sibling, leader) {
472 		if (is_software_event(sibling))
473 			continue;
474 		if (sibling->pmu != event->pmu)
475 			return false;
476 		counters += event_num_counters(sibling);
477 	}
478 
479 	/*
480 	 * If the group requires more counters than the HW has, it
481 	 * cannot ever be scheduled.
482 	 */
483 	return counters <= L3_NUM_COUNTERS;
484 }
485 
486 static int qcom_l3_cache__event_init(struct perf_event *event)
487 {
488 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(event->pmu);
489 	struct hw_perf_event *hwc = &event->hw;
490 
491 	/*
492 	 * Is the event for this PMU?
493 	 */
494 	if (event->attr.type != event->pmu->type)
495 		return -ENOENT;
496 
497 	/*
498 	 * Sampling not supported since these events are not core-attributable.
499 	 */
500 	if (hwc->sample_period)
501 		return -EINVAL;
502 
503 	/*
504 	 * Task mode not available, we run the counters as socket counters,
505 	 * not attributable to any CPU and therefore cannot attribute per-task.
506 	 */
507 	if (event->cpu < 0)
508 		return -EINVAL;
509 
510 	/* Validate the group */
511 	if (!qcom_l3_cache__validate_event_group(event))
512 		return -EINVAL;
513 
514 	hwc->idx = -1;
515 
516 	/*
517 	 * Many perf core operations (eg. events rotation) operate on a
518 	 * single CPU context. This is obvious for CPU PMUs, where one
519 	 * expects the same sets of events being observed on all CPUs,
520 	 * but can lead to issues for off-core PMUs, like this one, where
521 	 * each event could be theoretically assigned to a different CPU.
522 	 * To mitigate this, we enforce CPU assignment to one designated
523 	 * processor (the one described in the "cpumask" attribute exported
524 	 * by the PMU device). perf user space tools honor this and avoid
525 	 * opening more than one copy of the events.
526 	 */
527 	event->cpu = cpumask_first(&l3pmu->cpumask);
528 
529 	return 0;
530 }
531 
532 static void qcom_l3_cache__event_start(struct perf_event *event, int flags)
533 {
534 	struct hw_perf_event *hwc = &event->hw;
535 	const struct l3cache_event_ops *ops = l3cache_event_get_ops(event);
536 
537 	hwc->state = 0;
538 	ops->start(event);
539 }
540 
541 static void qcom_l3_cache__event_stop(struct perf_event *event, int flags)
542 {
543 	struct hw_perf_event *hwc = &event->hw;
544 	const struct l3cache_event_ops *ops = l3cache_event_get_ops(event);
545 
546 	if (hwc->state & PERF_HES_STOPPED)
547 		return;
548 
549 	ops->stop(event, flags);
550 	if (flags & PERF_EF_UPDATE)
551 		ops->update(event);
552 	hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
553 }
554 
555 static int qcom_l3_cache__event_add(struct perf_event *event, int flags)
556 {
557 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(event->pmu);
558 	struct hw_perf_event *hwc = &event->hw;
559 	int order = event_uses_long_counter(event) ? 1 : 0;
560 	int idx;
561 
562 	/*
563 	 * Try to allocate a counter.
564 	 */
565 	idx = bitmap_find_free_region(l3pmu->used_mask, L3_NUM_COUNTERS, order);
566 	if (idx < 0)
567 		/* The counters are all in use. */
568 		return -EAGAIN;
569 
570 	hwc->idx = idx;
571 	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
572 	l3pmu->events[idx] = event;
573 
574 	if (flags & PERF_EF_START)
575 		qcom_l3_cache__event_start(event, 0);
576 
577 	/* Propagate changes to the userspace mapping. */
578 	perf_event_update_userpage(event);
579 
580 	return 0;
581 }
582 
583 static void qcom_l3_cache__event_del(struct perf_event *event, int flags)
584 {
585 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(event->pmu);
586 	struct hw_perf_event *hwc = &event->hw;
587 	int order = event_uses_long_counter(event) ? 1 : 0;
588 
589 	/* Stop and clean up */
590 	qcom_l3_cache__event_stop(event,  flags | PERF_EF_UPDATE);
591 	l3pmu->events[hwc->idx] = NULL;
592 	bitmap_release_region(l3pmu->used_mask, hwc->idx, order);
593 
594 	/* Propagate changes to the userspace mapping. */
595 	perf_event_update_userpage(event);
596 }
597 
598 static void qcom_l3_cache__event_read(struct perf_event *event)
599 {
600 	const struct l3cache_event_ops *ops = l3cache_event_get_ops(event);
601 
602 	ops->update(event);
603 }
604 
605 /*
606  * Add sysfs attributes
607  *
608  * We export:
609  * - formats, used by perf user space and other tools to configure events
610  * - events, used by perf user space and other tools to create events
611  *   symbolically, e.g.:
612  *     perf stat -a -e l3cache_0_0/event=read-miss/ ls
613  *     perf stat -a -e l3cache_0_0/event=0x21/ ls
614  * - cpumask, used by perf user space and other tools to know on which CPUs
615  *   to open the events
616  */
617 
618 /* formats */
619 
620 static ssize_t l3cache_pmu_format_show(struct device *dev,
621 				       struct device_attribute *attr, char *buf)
622 {
623 	struct dev_ext_attribute *eattr;
624 
625 	eattr = container_of(attr, struct dev_ext_attribute, attr);
626 	return sprintf(buf, "%s\n", (char *) eattr->var);
627 }
628 
629 #define L3CACHE_PMU_FORMAT_ATTR(_name, _config)				      \
630 	(&((struct dev_ext_attribute[]) {				      \
631 		{ .attr = __ATTR(_name, 0444, l3cache_pmu_format_show, NULL), \
632 		  .var = (void *) _config, }				      \
633 	})[0].attr.attr)
634 
635 static struct attribute *qcom_l3_cache_pmu_formats[] = {
636 	L3CACHE_PMU_FORMAT_ATTR(event, "config:0-7"),
637 	L3CACHE_PMU_FORMAT_ATTR(lc, "config:" __stringify(L3_EVENT_LC_BIT)),
638 	NULL,
639 };
640 
641 static struct attribute_group qcom_l3_cache_pmu_format_group = {
642 	.name = "format",
643 	.attrs = qcom_l3_cache_pmu_formats,
644 };
645 
646 /* events */
647 
648 static ssize_t l3cache_pmu_event_show(struct device *dev,
649 				     struct device_attribute *attr, char *page)
650 {
651 	struct perf_pmu_events_attr *pmu_attr;
652 
653 	pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
654 	return sprintf(page, "event=0x%02llx\n", pmu_attr->id);
655 }
656 
657 #define L3CACHE_EVENT_ATTR(_name, _id)					     \
658 	(&((struct perf_pmu_events_attr[]) {				     \
659 		{ .attr = __ATTR(_name, 0444, l3cache_pmu_event_show, NULL), \
660 		  .id = _id, }						     \
661 	})[0].attr.attr)
662 
663 static struct attribute *qcom_l3_cache_pmu_events[] = {
664 	L3CACHE_EVENT_ATTR(cycles, L3_EVENT_CYCLES),
665 	L3CACHE_EVENT_ATTR(read-hit, L3_EVENT_READ_HIT),
666 	L3CACHE_EVENT_ATTR(read-miss, L3_EVENT_READ_MISS),
667 	L3CACHE_EVENT_ATTR(read-hit-d-side, L3_EVENT_READ_HIT_D),
668 	L3CACHE_EVENT_ATTR(read-miss-d-side, L3_EVENT_READ_MISS_D),
669 	L3CACHE_EVENT_ATTR(write-hit, L3_EVENT_WRITE_HIT),
670 	L3CACHE_EVENT_ATTR(write-miss, L3_EVENT_WRITE_MISS),
671 	NULL
672 };
673 
674 static struct attribute_group qcom_l3_cache_pmu_events_group = {
675 	.name = "events",
676 	.attrs = qcom_l3_cache_pmu_events,
677 };
678 
679 /* cpumask */
680 
681 static ssize_t qcom_l3_cache_pmu_cpumask_show(struct device *dev,
682 				     struct device_attribute *attr, char *buf)
683 {
684 	struct l3cache_pmu *l3pmu = to_l3cache_pmu(dev_get_drvdata(dev));
685 
686 	return cpumap_print_to_pagebuf(true, buf, &l3pmu->cpumask);
687 }
688 
689 static DEVICE_ATTR(cpumask, 0444, qcom_l3_cache_pmu_cpumask_show, NULL);
690 
691 static struct attribute *qcom_l3_cache_pmu_cpumask_attrs[] = {
692 	&dev_attr_cpumask.attr,
693 	NULL,
694 };
695 
696 static struct attribute_group qcom_l3_cache_pmu_cpumask_attr_group = {
697 	.attrs = qcom_l3_cache_pmu_cpumask_attrs,
698 };
699 
700 /*
701  * Per PMU device attribute groups
702  */
703 static const struct attribute_group *qcom_l3_cache_pmu_attr_grps[] = {
704 	&qcom_l3_cache_pmu_format_group,
705 	&qcom_l3_cache_pmu_events_group,
706 	&qcom_l3_cache_pmu_cpumask_attr_group,
707 	NULL,
708 };
709 
710 /*
711  * Probing functions and data.
712  */
713 
714 static int qcom_l3_cache_pmu_online_cpu(unsigned int cpu, struct hlist_node *node)
715 {
716 	struct l3cache_pmu *l3pmu = hlist_entry_safe(node, struct l3cache_pmu, node);
717 
718 	/* If there is not a CPU/PMU association pick this CPU */
719 	if (cpumask_empty(&l3pmu->cpumask))
720 		cpumask_set_cpu(cpu, &l3pmu->cpumask);
721 
722 	return 0;
723 }
724 
725 static int qcom_l3_cache_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
726 {
727 	struct l3cache_pmu *l3pmu = hlist_entry_safe(node, struct l3cache_pmu, node);
728 	unsigned int target;
729 
730 	if (!cpumask_test_and_clear_cpu(cpu, &l3pmu->cpumask))
731 		return 0;
732 	target = cpumask_any_but(cpu_online_mask, cpu);
733 	if (target >= nr_cpu_ids)
734 		return 0;
735 	perf_pmu_migrate_context(&l3pmu->pmu, cpu, target);
736 	cpumask_set_cpu(target, &l3pmu->cpumask);
737 	return 0;
738 }
739 
740 static int qcom_l3_cache_pmu_probe(struct platform_device *pdev)
741 {
742 	struct l3cache_pmu *l3pmu;
743 	struct acpi_device *acpi_dev;
744 	struct resource *memrc;
745 	int ret;
746 	char *name;
747 
748 	/* Initialize the PMU data structures */
749 
750 	acpi_dev = ACPI_COMPANION(&pdev->dev);
751 	if (!acpi_dev)
752 		return -ENODEV;
753 
754 	l3pmu = devm_kzalloc(&pdev->dev, sizeof(*l3pmu), GFP_KERNEL);
755 	name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "l3cache_%s_%s",
756 		      acpi_dev->parent->pnp.unique_id, acpi_dev->pnp.unique_id);
757 	if (!l3pmu || !name)
758 		return -ENOMEM;
759 
760 	l3pmu->pmu = (struct pmu) {
761 		.task_ctx_nr	= perf_invalid_context,
762 
763 		.pmu_enable	= qcom_l3_cache__pmu_enable,
764 		.pmu_disable	= qcom_l3_cache__pmu_disable,
765 		.event_init	= qcom_l3_cache__event_init,
766 		.add		= qcom_l3_cache__event_add,
767 		.del		= qcom_l3_cache__event_del,
768 		.start		= qcom_l3_cache__event_start,
769 		.stop		= qcom_l3_cache__event_stop,
770 		.read		= qcom_l3_cache__event_read,
771 
772 		.attr_groups	= qcom_l3_cache_pmu_attr_grps,
773 		.capabilities	= PERF_PMU_CAP_NO_EXCLUDE,
774 	};
775 
776 	memrc = platform_get_resource(pdev, IORESOURCE_MEM, 0);
777 	l3pmu->regs = devm_ioremap_resource(&pdev->dev, memrc);
778 	if (IS_ERR(l3pmu->regs)) {
779 		dev_err(&pdev->dev, "Can't map PMU @%pa\n", &memrc->start);
780 		return PTR_ERR(l3pmu->regs);
781 	}
782 
783 	qcom_l3_cache__init(l3pmu);
784 
785 	ret = platform_get_irq(pdev, 0);
786 	if (ret <= 0)
787 		return ret;
788 
789 	ret = devm_request_irq(&pdev->dev, ret, qcom_l3_cache__handle_irq, 0,
790 			       name, l3pmu);
791 	if (ret) {
792 		dev_err(&pdev->dev, "Request for IRQ failed for slice @%pa\n",
793 			&memrc->start);
794 		return ret;
795 	}
796 
797 	/* Add this instance to the list used by the offline callback */
798 	ret = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE, &l3pmu->node);
799 	if (ret) {
800 		dev_err(&pdev->dev, "Error %d registering hotplug", ret);
801 		return ret;
802 	}
803 
804 	ret = perf_pmu_register(&l3pmu->pmu, name, -1);
805 	if (ret < 0) {
806 		dev_err(&pdev->dev, "Failed to register L3 cache PMU (%d)\n", ret);
807 		return ret;
808 	}
809 
810 	dev_info(&pdev->dev, "Registered %s, type: %d\n", name, l3pmu->pmu.type);
811 
812 	return 0;
813 }
814 
815 static const struct acpi_device_id qcom_l3_cache_pmu_acpi_match[] = {
816 	{ "QCOM8081", },
817 	{ }
818 };
819 MODULE_DEVICE_TABLE(acpi, qcom_l3_cache_pmu_acpi_match);
820 
821 static struct platform_driver qcom_l3_cache_pmu_driver = {
822 	.driver = {
823 		.name = "qcom-l3cache-pmu",
824 		.acpi_match_table = ACPI_PTR(qcom_l3_cache_pmu_acpi_match),
825 	},
826 	.probe = qcom_l3_cache_pmu_probe,
827 };
828 
829 static int __init register_qcom_l3_cache_pmu_driver(void)
830 {
831 	int ret;
832 
833 	/* Install a hook to update the reader CPU in case it goes offline */
834 	ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE,
835 				      "perf/qcom/l3cache:online",
836 				      qcom_l3_cache_pmu_online_cpu,
837 				      qcom_l3_cache_pmu_offline_cpu);
838 	if (ret)
839 		return ret;
840 
841 	return platform_driver_register(&qcom_l3_cache_pmu_driver);
842 }
843 device_initcall(register_qcom_l3_cache_pmu_driver);
844