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1/*
2 * Linux performance counter support for ARC700 series
3 *
4 * Copyright (C) 2013-2015 Synopsys, Inc. (www.synopsys.com)
5 *
6 * This code is inspired by the perf support of various other architectures.
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 */
13#include <linux/errno.h>
14#include <linux/interrupt.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/perf_event.h>
18#include <linux/platform_device.h>
19#include <asm/arcregs.h>
20#include <asm/stacktrace.h>
21
22struct arc_pmu {
23 struct pmu pmu;
24 unsigned int irq;
25 int n_counters;
26 u64 max_period;
27 int ev_hw_idx[PERF_COUNT_ARC_HW_MAX];
28};
29
30struct arc_pmu_cpu {
31 /*
32 * A 1 bit for an index indicates that the counter is being used for
33 * an event. A 0 means that the counter can be used.
34 */
35 unsigned long used_mask[BITS_TO_LONGS(ARC_PERF_MAX_COUNTERS)];
36
37 /*
38 * The events that are active on the PMU for the given index.
39 */
40 struct perf_event *act_counter[ARC_PERF_MAX_COUNTERS];
41};
42
43struct arc_callchain_trace {
44 int depth;
45 void *perf_stuff;
46};
47
48static int callchain_trace(unsigned int addr, void *data)
49{
50 struct arc_callchain_trace *ctrl = data;
51 struct perf_callchain_entry_ctx *entry = ctrl->perf_stuff;
52 perf_callchain_store(entry, addr);
53
54 if (ctrl->depth++ < 3)
55 return 0;
56
57 return -1;
58}
59
60void
61perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
62{
63 struct arc_callchain_trace ctrl = {
64 .depth = 0,
65 .perf_stuff = entry,
66 };
67
68 arc_unwind_core(NULL, regs, callchain_trace, &ctrl);
69}
70
71void
72perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs)
73{
74 /*
75 * User stack can't be unwound trivially with kernel dwarf unwinder
76 * So for now just record the user PC
77 */
78 perf_callchain_store(entry, instruction_pointer(regs));
79}
80
81static struct arc_pmu *arc_pmu;
82static DEFINE_PER_CPU(struct arc_pmu_cpu, arc_pmu_cpu);
83
84/* read counter #idx; note that counter# != event# on ARC! */
85static uint64_t arc_pmu_read_counter(int idx)
86{
87 uint32_t tmp;
88 uint64_t result;
89
90 /*
91 * ARC supports making 'snapshots' of the counters, so we don't
92 * need to care about counters wrapping to 0 underneath our feet
93 */
94 write_aux_reg(ARC_REG_PCT_INDEX, idx);
95 tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
96 write_aux_reg(ARC_REG_PCT_CONTROL, tmp | ARC_REG_PCT_CONTROL_SN);
97 result = (uint64_t) (read_aux_reg(ARC_REG_PCT_SNAPH)) << 32;
98 result |= read_aux_reg(ARC_REG_PCT_SNAPL);
99
100 return result;
101}
102
103static void arc_perf_event_update(struct perf_event *event,
104 struct hw_perf_event *hwc, int idx)
105{
106 uint64_t prev_raw_count = local64_read(&hwc->prev_count);
107 uint64_t new_raw_count = arc_pmu_read_counter(idx);
108 int64_t delta = new_raw_count - prev_raw_count;
109
110 /*
111 * We aren't afraid of hwc->prev_count changing beneath our feet
112 * because there's no way for us to re-enter this function anytime.
113 */
114 local64_set(&hwc->prev_count, new_raw_count);
115 local64_add(delta, &event->count);
116 local64_sub(delta, &hwc->period_left);
117}
118
119static void arc_pmu_read(struct perf_event *event)
120{
121 arc_perf_event_update(event, &event->hw, event->hw.idx);
122}
123
124static int arc_pmu_cache_event(u64 config)
125{
126 unsigned int cache_type, cache_op, cache_result;
127 int ret;
128
129 cache_type = (config >> 0) & 0xff;
130 cache_op = (config >> 8) & 0xff;
131 cache_result = (config >> 16) & 0xff;
132 if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
133 return -EINVAL;
134 if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
135 return -EINVAL;
136 if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
137 return -EINVAL;
138
139 ret = arc_pmu_cache_map[cache_type][cache_op][cache_result];
140
141 if (ret == CACHE_OP_UNSUPPORTED)
142 return -ENOENT;
143
144 pr_debug("init cache event: type/op/result %d/%d/%d with h/w %d \'%s\'\n",
145 cache_type, cache_op, cache_result, ret,
146 arc_pmu_ev_hw_map[ret]);
147
148 return ret;
149}
150
151/* initializes hw_perf_event structure if event is supported */
152static int arc_pmu_event_init(struct perf_event *event)
153{
154 struct hw_perf_event *hwc = &event->hw;
155 int ret;
156
157 if (!is_sampling_event(event)) {
158 hwc->sample_period = arc_pmu->max_period;
159 hwc->last_period = hwc->sample_period;
160 local64_set(&hwc->period_left, hwc->sample_period);
161 }
162
163 hwc->config = 0;
164
165 if (is_isa_arcv2()) {
166 /* "exclude user" means "count only kernel" */
167 if (event->attr.exclude_user)
168 hwc->config |= ARC_REG_PCT_CONFIG_KERN;
169
170 /* "exclude kernel" means "count only user" */
171 if (event->attr.exclude_kernel)
172 hwc->config |= ARC_REG_PCT_CONFIG_USER;
173 }
174
175 switch (event->attr.type) {
176 case PERF_TYPE_HARDWARE:
177 if (event->attr.config >= PERF_COUNT_HW_MAX)
178 return -ENOENT;
179 if (arc_pmu->ev_hw_idx[event->attr.config] < 0)
180 return -ENOENT;
181 hwc->config |= arc_pmu->ev_hw_idx[event->attr.config];
182 pr_debug("init event %d with h/w %08x \'%s\'\n",
183 (int)event->attr.config, (int)hwc->config,
184 arc_pmu_ev_hw_map[event->attr.config]);
185 return 0;
186
187 case PERF_TYPE_HW_CACHE:
188 ret = arc_pmu_cache_event(event->attr.config);
189 if (ret < 0)
190 return ret;
191 hwc->config |= arc_pmu->ev_hw_idx[ret];
192 pr_debug("init cache event with h/w %08x \'%s\'\n",
193 (int)hwc->config, arc_pmu_ev_hw_map[ret]);
194 return 0;
195 default:
196 return -ENOENT;
197 }
198}
199
200/* starts all counters */
201static void arc_pmu_enable(struct pmu *pmu)
202{
203 uint32_t tmp;
204 tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
205 write_aux_reg(ARC_REG_PCT_CONTROL, (tmp & 0xffff0000) | 0x1);
206}
207
208/* stops all counters */
209static void arc_pmu_disable(struct pmu *pmu)
210{
211 uint32_t tmp;
212 tmp = read_aux_reg(ARC_REG_PCT_CONTROL);
213 write_aux_reg(ARC_REG_PCT_CONTROL, (tmp & 0xffff0000) | 0x0);
214}
215
216static int arc_pmu_event_set_period(struct perf_event *event)
217{
218 struct hw_perf_event *hwc = &event->hw;
219 s64 left = local64_read(&hwc->period_left);
220 s64 period = hwc->sample_period;
221 int idx = hwc->idx;
222 int overflow = 0;
223 u64 value;
224
225 if (unlikely(left <= -period)) {
226 /* left underflowed by more than period. */
227 left = period;
228 local64_set(&hwc->period_left, left);
229 hwc->last_period = period;
230 overflow = 1;
231 } else if (unlikely(left <= 0)) {
232 /* left underflowed by less than period. */
233 left += period;
234 local64_set(&hwc->period_left, left);
235 hwc->last_period = period;
236 overflow = 1;
237 }
238
239 if (left > arc_pmu->max_period)
240 left = arc_pmu->max_period;
241
242 value = arc_pmu->max_period - left;
243 local64_set(&hwc->prev_count, value);
244
245 /* Select counter */
246 write_aux_reg(ARC_REG_PCT_INDEX, idx);
247
248 /* Write value */
249 write_aux_reg(ARC_REG_PCT_COUNTL, (u32)value);
250 write_aux_reg(ARC_REG_PCT_COUNTH, (value >> 32));
251
252 perf_event_update_userpage(event);
253
254 return overflow;
255}
256
257/*
258 * Assigns hardware counter to hardware condition.
259 * Note that there is no separate start/stop mechanism;
260 * stopping is achieved by assigning the 'never' condition
261 */
262static void arc_pmu_start(struct perf_event *event, int flags)
263{
264 struct hw_perf_event *hwc = &event->hw;
265 int idx = hwc->idx;
266
267 if (WARN_ON_ONCE(idx == -1))
268 return;
269
270 if (flags & PERF_EF_RELOAD)
271 WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
272
273 hwc->state = 0;
274
275 arc_pmu_event_set_period(event);
276
277 /* Enable interrupt for this counter */
278 if (is_sampling_event(event))
279 write_aux_reg(ARC_REG_PCT_INT_CTRL,
280 read_aux_reg(ARC_REG_PCT_INT_CTRL) | (1 << idx));
281
282 /* enable ARC pmu here */
283 write_aux_reg(ARC_REG_PCT_INDEX, idx); /* counter # */
284 write_aux_reg(ARC_REG_PCT_CONFIG, hwc->config); /* condition */
285}
286
287static void arc_pmu_stop(struct perf_event *event, int flags)
288{
289 struct hw_perf_event *hwc = &event->hw;
290 int idx = hwc->idx;
291
292 /* Disable interrupt for this counter */
293 if (is_sampling_event(event)) {
294 /*
295 * Reset interrupt flag by writing of 1. This is required
296 * to make sure pending interrupt was not left.
297 */
298 write_aux_reg(ARC_REG_PCT_INT_ACT, 1 << idx);
299 write_aux_reg(ARC_REG_PCT_INT_CTRL,
300 read_aux_reg(ARC_REG_PCT_INT_CTRL) & ~(1 << idx));
301 }
302
303 if (!(event->hw.state & PERF_HES_STOPPED)) {
304 /* stop ARC pmu here */
305 write_aux_reg(ARC_REG_PCT_INDEX, idx);
306
307 /* condition code #0 is always "never" */
308 write_aux_reg(ARC_REG_PCT_CONFIG, 0);
309
310 event->hw.state |= PERF_HES_STOPPED;
311 }
312
313 if ((flags & PERF_EF_UPDATE) &&
314 !(event->hw.state & PERF_HES_UPTODATE)) {
315 arc_perf_event_update(event, &event->hw, idx);
316 event->hw.state |= PERF_HES_UPTODATE;
317 }
318}
319
320static void arc_pmu_del(struct perf_event *event, int flags)
321{
322 struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu);
323
324 arc_pmu_stop(event, PERF_EF_UPDATE);
325 __clear_bit(event->hw.idx, pmu_cpu->used_mask);
326
327 pmu_cpu->act_counter[event->hw.idx] = 0;
328
329 perf_event_update_userpage(event);
330}
331
332/* allocate hardware counter and optionally start counting */
333static int arc_pmu_add(struct perf_event *event, int flags)
334{
335 struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu);
336 struct hw_perf_event *hwc = &event->hw;
337 int idx = hwc->idx;
338
339 if (__test_and_set_bit(idx, pmu_cpu->used_mask)) {
340 idx = find_first_zero_bit(pmu_cpu->used_mask,
341 arc_pmu->n_counters);
342 if (idx == arc_pmu->n_counters)
343 return -EAGAIN;
344
345 __set_bit(idx, pmu_cpu->used_mask);
346 hwc->idx = idx;
347 }
348
349 write_aux_reg(ARC_REG_PCT_INDEX, idx);
350
351 pmu_cpu->act_counter[idx] = event;
352
353 if (is_sampling_event(event)) {
354 /* Mimic full counter overflow as other arches do */
355 write_aux_reg(ARC_REG_PCT_INT_CNTL, (u32)arc_pmu->max_period);
356 write_aux_reg(ARC_REG_PCT_INT_CNTH,
357 (arc_pmu->max_period >> 32));
358 }
359
360 write_aux_reg(ARC_REG_PCT_CONFIG, 0);
361 write_aux_reg(ARC_REG_PCT_COUNTL, 0);
362 write_aux_reg(ARC_REG_PCT_COUNTH, 0);
363 local64_set(&hwc->prev_count, 0);
364
365 hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
366 if (flags & PERF_EF_START)
367 arc_pmu_start(event, PERF_EF_RELOAD);
368
369 perf_event_update_userpage(event);
370
371 return 0;
372}
373
374#ifdef CONFIG_ISA_ARCV2
375static irqreturn_t arc_pmu_intr(int irq, void *dev)
376{
377 struct perf_sample_data data;
378 struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu);
379 struct pt_regs *regs;
380 int active_ints;
381 int idx;
382
383 arc_pmu_disable(&arc_pmu->pmu);
384
385 active_ints = read_aux_reg(ARC_REG_PCT_INT_ACT);
386
387 regs = get_irq_regs();
388
389 for (idx = 0; idx < arc_pmu->n_counters; idx++) {
390 struct perf_event *event = pmu_cpu->act_counter[idx];
391 struct hw_perf_event *hwc;
392
393 if (!(active_ints & (1 << idx)))
394 continue;
395
396 /* Reset interrupt flag by writing of 1 */
397 write_aux_reg(ARC_REG_PCT_INT_ACT, 1 << idx);
398
399 /*
400 * On reset of "interrupt active" bit corresponding
401 * "interrupt enable" bit gets automatically reset as well.
402 * Now we need to re-enable interrupt for the counter.
403 */
404 write_aux_reg(ARC_REG_PCT_INT_CTRL,
405 read_aux_reg(ARC_REG_PCT_INT_CTRL) | (1 << idx));
406
407 hwc = &event->hw;
408
409 WARN_ON_ONCE(hwc->idx != idx);
410
411 arc_perf_event_update(event, &event->hw, event->hw.idx);
412 perf_sample_data_init(&data, 0, hwc->last_period);
413 if (!arc_pmu_event_set_period(event))
414 continue;
415
416 if (perf_event_overflow(event, &data, regs))
417 arc_pmu_stop(event, 0);
418 }
419
420 arc_pmu_enable(&arc_pmu->pmu);
421
422 return IRQ_HANDLED;
423}
424#else
425
426static irqreturn_t arc_pmu_intr(int irq, void *dev)
427{
428 return IRQ_NONE;
429}
430
431#endif /* CONFIG_ISA_ARCV2 */
432
433static void arc_cpu_pmu_irq_init(void *data)
434{
435 int irq = *(int *)data;
436
437 enable_percpu_irq(irq, IRQ_TYPE_NONE);
438
439 /* Clear all pending interrupt flags */
440 write_aux_reg(ARC_REG_PCT_INT_ACT, 0xffffffff);
441}
442
443static int arc_pmu_device_probe(struct platform_device *pdev)
444{
445 struct arc_reg_pct_build pct_bcr;
446 struct arc_reg_cc_build cc_bcr;
447 int i, j, has_interrupts;
448 int counter_size; /* in bits */
449
450 union cc_name {
451 struct {
452 uint32_t word0, word1;
453 char sentinel;
454 } indiv;
455 char str[9];
456 } cc_name;
457
458
459 READ_BCR(ARC_REG_PCT_BUILD, pct_bcr);
460 if (!pct_bcr.v) {
461 pr_err("This core does not have performance counters!\n");
462 return -ENODEV;
463 }
464 BUG_ON(pct_bcr.c > ARC_PERF_MAX_COUNTERS);
465
466 READ_BCR(ARC_REG_CC_BUILD, cc_bcr);
467 BUG_ON(!cc_bcr.v); /* Counters exist but No countable conditions ? */
468
469 arc_pmu = devm_kzalloc(&pdev->dev, sizeof(struct arc_pmu), GFP_KERNEL);
470 if (!arc_pmu)
471 return -ENOMEM;
472
473 has_interrupts = is_isa_arcv2() ? pct_bcr.i : 0;
474
475 arc_pmu->n_counters = pct_bcr.c;
476 counter_size = 32 + (pct_bcr.s << 4);
477
478 arc_pmu->max_period = (1ULL << counter_size) / 2 - 1ULL;
479
480 pr_info("ARC perf\t: %d counters (%d bits), %d conditions%s\n",
481 arc_pmu->n_counters, counter_size, cc_bcr.c,
482 has_interrupts ? ", [overflow IRQ support]":"");
483
484 cc_name.str[8] = 0;
485 for (i = 0; i < PERF_COUNT_ARC_HW_MAX; i++)
486 arc_pmu->ev_hw_idx[i] = -1;
487
488 /* loop thru all available h/w condition indexes */
489 for (j = 0; j < cc_bcr.c; j++) {
490 write_aux_reg(ARC_REG_CC_INDEX, j);
491 cc_name.indiv.word0 = read_aux_reg(ARC_REG_CC_NAME0);
492 cc_name.indiv.word1 = read_aux_reg(ARC_REG_CC_NAME1);
493
494 /* See if it has been mapped to a perf event_id */
495 for (i = 0; i < ARRAY_SIZE(arc_pmu_ev_hw_map); i++) {
496 if (arc_pmu_ev_hw_map[i] &&
497 !strcmp(arc_pmu_ev_hw_map[i], cc_name.str) &&
498 strlen(arc_pmu_ev_hw_map[i])) {
499 pr_debug("mapping perf event %2d to h/w event \'%8s\' (idx %d)\n",
500 i, cc_name.str, j);
501 arc_pmu->ev_hw_idx[i] = j;
502 }
503 }
504 }
505
506 arc_pmu->pmu = (struct pmu) {
507 .pmu_enable = arc_pmu_enable,
508 .pmu_disable = arc_pmu_disable,
509 .event_init = arc_pmu_event_init,
510 .add = arc_pmu_add,
511 .del = arc_pmu_del,
512 .start = arc_pmu_start,
513 .stop = arc_pmu_stop,
514 .read = arc_pmu_read,
515 };
516
517 if (has_interrupts) {
518 int irq = platform_get_irq(pdev, 0);
519
520 if (irq < 0) {
521 pr_err("Cannot get IRQ number for the platform\n");
522 return -ENODEV;
523 }
524
525 arc_pmu->irq = irq;
526
527 /* intc map function ensures irq_set_percpu_devid() called */
528 request_percpu_irq(irq, arc_pmu_intr, "ARC perf counters",
529 this_cpu_ptr(&arc_pmu_cpu));
530
531 on_each_cpu(arc_cpu_pmu_irq_init, &irq, 1);
532
533 } else
534 arc_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
535
536 return perf_pmu_register(&arc_pmu->pmu, pdev->name, PERF_TYPE_RAW);
537}
538
539#ifdef CONFIG_OF
540static const struct of_device_id arc_pmu_match[] = {
541 { .compatible = "snps,arc700-pct" },
542 { .compatible = "snps,archs-pct" },
543 {},
544};
545MODULE_DEVICE_TABLE(of, arc_pmu_match);
546#endif
547
548static struct platform_driver arc_pmu_driver = {
549 .driver = {
550 .name = "arc-pct",
551 .of_match_table = of_match_ptr(arc_pmu_match),
552 },
553 .probe = arc_pmu_device_probe,
554};
555
556module_platform_driver(arc_pmu_driver);
557
558MODULE_LICENSE("GPL");
559MODULE_AUTHOR("Mischa Jonker <mjonker@synopsys.com>");
560MODULE_DESCRIPTION("ARC PMU driver");