arch/arm/mm/cache-l2x0-pmu.c

   1 /*
   2  * L220/L310 cache controller support
   3  *
   4  * Copyright (C) 2016 ARM Limited
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  18  */
  19 #include <linux/errno.h>
  20 #include <linux/hrtimer.h>
  21 #include <linux/io.h>
  22 #include <linux/list.h>
  23 #include <linux/perf_event.h>
  24 #include <linux/printk.h>
  25 #include <linux/slab.h>
  26 #include <linux/types.h>
  27
  28 #include <asm/hardware/cache-l2x0.h>
  29
  30 #define PMU_NR_COUNTERS 2
  31
  32 static void __iomem *l2x0_base;
  33 static struct pmu *l2x0_pmu;
  34 static cpumask_t pmu_cpu;
  35
  36 static const char *l2x0_name;
  37
  38 static ktime_t l2x0_pmu_poll_period;
  39 static struct hrtimer l2x0_pmu_hrtimer;
  40
  41 /*
  42  * The L220/PL310 PMU has two equivalent counters, Counter1 and Counter0.
  43  * Registers controlling these are laid out in pairs, in descending order, i.e.
  44  * the register for Counter1 comes first, followed by the register for
  45  * Counter0.
  46  * We ensure that idx 0 -> Counter0, and idx1 -> Counter1.
  47  */
  48 static struct perf_event *events[PMU_NR_COUNTERS];
  49
  50 /* Find an unused counter */
  51 static int l2x0_pmu_find_idx(void)
  52 {
  53         int i;
  54
  55         for (i = 0; i < PMU_NR_COUNTERS; i++) {
  56                 if (!events[i])
  57                         return i;
  58         }
  59
  60         return -1;
  61 }
  62
  63 /* How many counters are allocated? */
  64 static int l2x0_pmu_num_active_counters(void)
  65 {
  66         int i, cnt = 0;
  67
  68         for (i = 0; i < PMU_NR_COUNTERS; i++) {
  69                 if (events[i])
  70                         cnt++;
  71         }
  72
  73         return cnt;
  74 }
  75
  76 static void l2x0_pmu_counter_config_write(int idx, u32 val)
  77 {
  78         writel_relaxed(val, l2x0_base + L2X0_EVENT_CNT0_CFG - 4 * idx);
  79 }
  80
  81 static u32 l2x0_pmu_counter_read(int idx)
  82 {
  83         return readl_relaxed(l2x0_base + L2X0_EVENT_CNT0_VAL - 4 * idx);
  84 }
  85
  86 static void l2x0_pmu_counter_write(int idx, u32 val)
  87 {
  88         writel_relaxed(val, l2x0_base + L2X0_EVENT_CNT0_VAL - 4 * idx);
  89 }
  90
  91 static void __l2x0_pmu_enable(void)
  92 {
  93         u32 val = readl_relaxed(l2x0_base + L2X0_EVENT_CNT_CTRL);
  94         val |= L2X0_EVENT_CNT_CTRL_ENABLE;
  95         writel_relaxed(val, l2x0_base + L2X0_EVENT_CNT_CTRL);
  96 }
  97
  98 static void __l2x0_pmu_disable(void)
  99 {
 100         u32 val = readl_relaxed(l2x0_base + L2X0_EVENT_CNT_CTRL);
 101         val &= ~L2X0_EVENT_CNT_CTRL_ENABLE;
 102         writel_relaxed(val, l2x0_base + L2X0_EVENT_CNT_CTRL);
 103 }
 104
 105 static void l2x0_pmu_enable(struct pmu *pmu)
 106 {
 107         if (l2x0_pmu_num_active_counters() == 0)
 108                 return;
 109
 110         __l2x0_pmu_enable();
 111 }
 112
 113 static void l2x0_pmu_disable(struct pmu *pmu)
 114 {
 115         if (l2x0_pmu_num_active_counters() == 0)
 116                 return;
 117
 118         __l2x0_pmu_disable();
 119 }
 120
 121 static void warn_if_saturated(u32 count)
 122 {
 123         if (count != 0xffffffff)
 124                 return;
 125
 126         pr_warn_ratelimited("L2X0 counter saturated. Poll period too long\n");
 127 }
 128
 129 static void l2x0_pmu_event_read(struct perf_event *event)
 130 {
 131         struct hw_perf_event *hw = &event->hw;
 132         u64 prev_count, new_count, mask;
 133
 134         do {
 135                  prev_count = local64_read(&hw->prev_count);
 136                  new_count = l2x0_pmu_counter_read(hw->idx);
 137         } while (local64_xchg(&hw->prev_count, new_count) != prev_count);
 138
 139         mask = GENMASK_ULL(31, 0);
 140         local64_add((new_count - prev_count) & mask, &event->count);
 141
 142         warn_if_saturated(new_count);
 143 }
 144
 145 static void l2x0_pmu_event_configure(struct perf_event *event)
 146 {
 147         struct hw_perf_event *hw = &event->hw;
 148
 149         /*
 150          * The L2X0 counters saturate at 0xffffffff rather than wrapping, so we
 151          * will *always* lose some number of events when a counter saturates,
 152          * and have no way of detecting how many were lost.
 153          *
 154          * To minimize the impact of this, we try to maximize the period by
 155          * always starting counters at zero. To ensure that group ratios are
 156          * representative, we poll periodically to avoid counters saturating.
 157          * See l2x0_pmu_poll().
 158          */
 159         local64_set(&hw->prev_count, 0);
 160         l2x0_pmu_counter_write(hw->idx, 0);
 161 }
 162
 163 static enum hrtimer_restart l2x0_pmu_poll(struct hrtimer *hrtimer)
 164 {
 165         unsigned long flags;
 166         int i;
 167
 168         local_irq_save(flags);
 169         __l2x0_pmu_disable();
 170
 171         for (i = 0; i < PMU_NR_COUNTERS; i++) {
 172                 struct perf_event *event = events[i];
 173
 174                 if (!event)
 175                         continue;
 176
 177                 l2x0_pmu_event_read(event);
 178                 l2x0_pmu_event_configure(event);
 179         }
 180
 181         __l2x0_pmu_enable();
 182         local_irq_restore(flags);
 183
 184         hrtimer_forward_now(hrtimer, l2x0_pmu_poll_period);
 185         return HRTIMER_RESTART;
 186 }
 187
 188
 189 static void __l2x0_pmu_event_enable(int idx, u32 event)
 190 {
 191         u32 val;
 192
 193         val = event << L2X0_EVENT_CNT_CFG_SRC_SHIFT;
 194         val |= L2X0_EVENT_CNT_CFG_INT_DISABLED;
 195         l2x0_pmu_counter_config_write(idx, val);
 196 }
 197
 198 static void l2x0_pmu_event_start(struct perf_event *event, int flags)
 199 {
 200         struct hw_perf_event *hw = &event->hw;
 201
 202         if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
 203                 return;
 204
 205         if (flags & PERF_EF_RELOAD) {
 206                 WARN_ON_ONCE(!(hw->state & PERF_HES_UPTODATE));
 207                 l2x0_pmu_event_configure(event);
 208         }
 209
 210         hw->state = 0;
 211
 212         __l2x0_pmu_event_enable(hw->idx, hw->config_base);
 213 }
 214
 215 static void __l2x0_pmu_event_disable(int idx)
 216 {
 217         u32 val;
 218
 219         val = L2X0_EVENT_CNT_CFG_SRC_DISABLED << L2X0_EVENT_CNT_CFG_SRC_SHIFT;
 220         val |= L2X0_EVENT_CNT_CFG_INT_DISABLED;
 221         l2x0_pmu_counter_config_write(idx, val);
 222 }
 223
 224 static void l2x0_pmu_event_stop(struct perf_event *event, int flags)
 225 {
 226         struct hw_perf_event *hw = &event->hw;
 227
 228         if (WARN_ON_ONCE(event->hw.state & PERF_HES_STOPPED))
 229                 return;
 230
 231         __l2x0_pmu_event_disable(hw->idx);
 232
 233         hw->state |= PERF_HES_STOPPED;
 234
 235         if (flags & PERF_EF_UPDATE) {
 236                 l2x0_pmu_event_read(event);
 237                 hw->state |= PERF_HES_UPTODATE;
 238         }
 239 }
 240
 241 static int l2x0_pmu_event_add(struct perf_event *event, int flags)
 242 {
 243         struct hw_perf_event *hw = &event->hw;
 244         int idx = l2x0_pmu_find_idx();
 245
 246         if (idx == -1)
 247                 return -EAGAIN;
 248
 249         /*
 250          * Pin the timer, so that the overflows are handled by the chosen
 251          * event->cpu (this is the same one as presented in "cpumask"
 252          * attribute).
 253          */
 254         if (l2x0_pmu_num_active_counters() == 0)
 255                 hrtimer_start(&l2x0_pmu_hrtimer, l2x0_pmu_poll_period,
 256                               HRTIMER_MODE_REL_PINNED);
 257
 258         events[idx] = event;
 259         hw->idx = idx;
 260
 261         l2x0_pmu_event_configure(event);
 262
 263         hw->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
 264
 265         if (flags & PERF_EF_START)
 266                 l2x0_pmu_event_start(event, 0);
 267
 268         return 0;
 269 }
 270
 271 static void l2x0_pmu_event_del(struct perf_event *event, int flags)
 272 {
 273         struct hw_perf_event *hw = &event->hw;
 274
 275         l2x0_pmu_event_stop(event, PERF_EF_UPDATE);
 276
 277         events[hw->idx] = NULL;
 278         hw->idx = -1;
 279
 280         if (l2x0_pmu_num_active_counters() == 0)
 281                 hrtimer_cancel(&l2x0_pmu_hrtimer);
 282 }
 283
 284 static bool l2x0_pmu_group_is_valid(struct perf_event *event)
 285 {
 286         struct pmu *pmu = event->pmu;
 287         struct perf_event *leader = event->group_leader;
 288         struct perf_event *sibling;
 289         int num_hw = 0;
 290
 291         if (leader->pmu == pmu)
 292                 num_hw++;
 293         else if (!is_software_event(leader))
 294                 return false;
 295
 296         for_each_sibling_event(sibling, leader) {
 297                 if (sibling->pmu == pmu)
 298                         num_hw++;
 299                 else if (!is_software_event(sibling))
 300                         return false;
 301         }
 302
 303         return num_hw <= PMU_NR_COUNTERS;
 304 }
 305
 306 static int l2x0_pmu_event_init(struct perf_event *event)
 307 {
 308         struct hw_perf_event *hw = &event->hw;
 309
 310         if (event->attr.type != l2x0_pmu->type)
 311                 return -ENOENT;
 312
 313         if (is_sampling_event(event) ||
 314             event->attach_state & PERF_ATTACH_TASK)
 315                 return -EINVAL;
 316
 317         if (event->cpu < 0)
 318                 return -EINVAL;
 319
 320         if (event->attr.config & ~L2X0_EVENT_CNT_CFG_SRC_MASK)
 321                 return -EINVAL;
 322
 323         hw->config_base = event->attr.config;
 324
 325         if (!l2x0_pmu_group_is_valid(event))
 326                 return -EINVAL;
 327
 328         event->cpu = cpumask_first(&pmu_cpu);
 329
 330         return 0;
 331 }
 332
 333 struct l2x0_event_attribute {
 334         struct device_attribute attr;
 335         unsigned int config;
 336         bool pl310_only;
 337 };
 338
 339 #define L2X0_EVENT_ATTR(_name, _config, _pl310_only)                            \
 340         (&((struct l2x0_event_attribute[]) {{                                   \
 341                 .attr = __ATTR(_name, S_IRUGO, l2x0_pmu_event_show, NULL),      \
 342                 .config = _config,                                              \
 343                 .pl310_only = _pl310_only,                                      \
 344         }})[0].attr.attr)
 345
 346 #define L220_PLUS_EVENT_ATTR(_name, _config)                                    \
 347         L2X0_EVENT_ATTR(_name, _config, false)
 348
 349 #define PL310_EVENT_ATTR(_name, _config)                                        \
 350         L2X0_EVENT_ATTR(_name, _config, true)
 351
 352 static ssize_t l2x0_pmu_event_show(struct device *dev,
 353                                    struct device_attribute *attr, char *buf)
 354 {
 355         struct l2x0_event_attribute *lattr;
 356
 357         lattr = container_of(attr, typeof(*lattr), attr);
 358         return snprintf(buf, PAGE_SIZE, "config=0x%x\n", lattr->config);
 359 }
 360
 361 static umode_t l2x0_pmu_event_attr_is_visible(struct kobject *kobj,
 362                                               struct attribute *attr,
 363                                               int unused)
 364 {
 365         struct device *dev = kobj_to_dev(kobj);
 366         struct pmu *pmu = dev_get_drvdata(dev);
 367         struct l2x0_event_attribute *lattr;
 368
 369         lattr = container_of(attr, typeof(*lattr), attr.attr);
 370
 371         if (!lattr->pl310_only || strcmp("l2c_310", pmu->name) == 0)
 372                 return attr->mode;
 373
 374         return 0;
 375 }
 376
 377 static struct attribute *l2x0_pmu_event_attrs[] = {
 378         L220_PLUS_EVENT_ATTR(co,        0x1),
 379         L220_PLUS_EVENT_ATTR(drhit,     0x2),
 380         L220_PLUS_EVENT_ATTR(drreq,     0x3),
 381         L220_PLUS_EVENT_ATTR(dwhit,     0x4),
 382         L220_PLUS_EVENT_ATTR(dwreq,     0x5),
 383         L220_PLUS_EVENT_ATTR(dwtreq,    0x6),
 384         L220_PLUS_EVENT_ATTR(irhit,     0x7),
 385         L220_PLUS_EVENT_ATTR(irreq,     0x8),
 386         L220_PLUS_EVENT_ATTR(wa,        0x9),
 387         PL310_EVENT_ATTR(ipfalloc,      0xa),
 388         PL310_EVENT_ATTR(epfhit,        0xb),
 389         PL310_EVENT_ATTR(epfalloc,      0xc),
 390         PL310_EVENT_ATTR(srrcvd,        0xd),
 391         PL310_EVENT_ATTR(srconf,        0xe),
 392         PL310_EVENT_ATTR(epfrcvd,       0xf),
 393         NULL
 394 };
 395
 396 static struct attribute_group l2x0_pmu_event_attrs_group = {
 397         .name = "events",
 398         .attrs = l2x0_pmu_event_attrs,
 399         .is_visible = l2x0_pmu_event_attr_is_visible,
 400 };
 401
 402 static ssize_t l2x0_pmu_cpumask_show(struct device *dev,
 403                                      struct device_attribute *attr, char *buf)
 404 {
 405         return cpumap_print_to_pagebuf(true, buf, &pmu_cpu);
 406 }
 407
 408 static struct device_attribute l2x0_pmu_cpumask_attr =
 409                 __ATTR(cpumask, S_IRUGO, l2x0_pmu_cpumask_show, NULL);
 410
 411 static struct attribute *l2x0_pmu_cpumask_attrs[] = {
 412         &l2x0_pmu_cpumask_attr.attr,
 413         NULL,
 414 };
 415
 416 static struct attribute_group l2x0_pmu_cpumask_attr_group = {
 417         .attrs = l2x0_pmu_cpumask_attrs,
 418 };
 419
 420 static const struct attribute_group *l2x0_pmu_attr_groups[] = {
 421         &l2x0_pmu_event_attrs_group,
 422         &l2x0_pmu_cpumask_attr_group,
 423         NULL,
 424 };
 425
 426 static void l2x0_pmu_reset(void)
 427 {
 428         int i;
 429
 430         __l2x0_pmu_disable();
 431
 432         for (i = 0; i < PMU_NR_COUNTERS; i++)
 433                 __l2x0_pmu_event_disable(i);
 434 }
 435
 436 static int l2x0_pmu_offline_cpu(unsigned int cpu)
 437 {
 438         unsigned int target;
 439
 440         if (!cpumask_test_and_clear_cpu(cpu, &pmu_cpu))
 441                 return 0;
 442
 443         target = cpumask_any_but(cpu_online_mask, cpu);
 444         if (target >= nr_cpu_ids)
 445                 return 0;
 446
 447         perf_pmu_migrate_context(l2x0_pmu, cpu, target);
 448         cpumask_set_cpu(target, &pmu_cpu);
 449
 450         return 0;
 451 }
 452
 453 void l2x0_pmu_suspend(void)
 454 {
 455         int i;
 456
 457         if (!l2x0_pmu)
 458                 return;
 459
 460         l2x0_pmu_disable(l2x0_pmu);
 461
 462         for (i = 0; i < PMU_NR_COUNTERS; i++) {
 463                 if (events[i])
 464                         l2x0_pmu_event_stop(events[i], PERF_EF_UPDATE);
 465         }
 466
 467 }
 468
 469 void l2x0_pmu_resume(void)
 470 {
 471         int i;
 472
 473         if (!l2x0_pmu)
 474                 return;
 475
 476         l2x0_pmu_reset();
 477
 478         for (i = 0; i < PMU_NR_COUNTERS; i++) {
 479                 if (events[i])
 480                         l2x0_pmu_event_start(events[i], PERF_EF_RELOAD);
 481         }
 482
 483         l2x0_pmu_enable(l2x0_pmu);
 484 }
 485
 486 void __init l2x0_pmu_register(void __iomem *base, u32 part)
 487 {
 488         /*
 489          * Determine whether we support the PMU, and choose the name for sysfs.
 490          * This is also used by l2x0_pmu_event_attr_is_visible to determine
 491          * which events to display, as the PL310 PMU supports a superset of
 492          * L220 events.
 493          *
 494          * The L210 PMU has a different programmer's interface, and is not
 495          * supported by this driver.
 496          *
 497          * We must defer registering the PMU until the perf subsystem is up and
 498          * running, so just stash the name and base, and leave that to another
 499          * initcall.
 500          */
 501         switch (part & L2X0_CACHE_ID_PART_MASK) {
 502         case L2X0_CACHE_ID_PART_L220:
 503                 l2x0_name = "l2c_220";
 504                 break;
 505         case L2X0_CACHE_ID_PART_L310:
 506                 l2x0_name = "l2c_310";
 507                 break;
 508         default:
 509                 return;
 510         }
 511
 512         l2x0_base = base;
 513 }
 514
 515 static __init int l2x0_pmu_init(void)
 516 {
 517         int ret;
 518
 519         if (!l2x0_base)
 520                 return 0;
 521
 522         l2x0_pmu = kzalloc(sizeof(*l2x0_pmu), GFP_KERNEL);
 523         if (!l2x0_pmu) {
 524                 pr_warn("Unable to allocate L2x0 PMU\n");
 525                 return -ENOMEM;
 526         }
 527
 528         *l2x0_pmu = (struct pmu) {
 529                 .task_ctx_nr = perf_invalid_context,
 530                 .pmu_enable = l2x0_pmu_enable,
 531                 .pmu_disable = l2x0_pmu_disable,
 532                 .read = l2x0_pmu_event_read,
 533                 .start = l2x0_pmu_event_start,
 534                 .stop = l2x0_pmu_event_stop,
 535                 .add = l2x0_pmu_event_add,
 536                 .del = l2x0_pmu_event_del,
 537                 .event_init = l2x0_pmu_event_init,
 538                 .attr_groups = l2x0_pmu_attr_groups,
 539                 .capabilities = PERF_PMU_CAP_NO_EXCLUDE,
 540         };
 541
 542         l2x0_pmu_reset();
 543
 544         /*
 545          * We always use a hrtimer rather than an interrupt.
 546          * See comments in l2x0_pmu_event_configure and l2x0_pmu_poll.
 547          *
 548          * Polling once a second allows the counters to fill up to 1/128th on a
 549          * quad-core test chip with cores clocked at 400MHz. Hopefully this
 550          * leaves sufficient headroom to avoid overflow on production silicon
 551          * at higher frequencies.
 552          */
 553         l2x0_pmu_poll_period = ms_to_ktime(1000);
 554         hrtimer_init(&l2x0_pmu_hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 555         l2x0_pmu_hrtimer.function = l2x0_pmu_poll;
 556
 557         cpumask_set_cpu(0, &pmu_cpu);
 558         ret = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_L2X0_ONLINE,
 559                                         "perf/arm/l2x0:online", NULL,
 560                                         l2x0_pmu_offline_cpu);
 561         if (ret)
 562                 goto out_pmu;
 563
 564         ret = perf_pmu_register(l2x0_pmu, l2x0_name, -1);
 565         if (ret)
 566                 goto out_cpuhp;
 567
 568         return 0;
 569
 570 out_cpuhp:
 571         cpuhp_remove_state_nocalls(CPUHP_AP_PERF_ARM_L2X0_ONLINE);
 572 out_pmu:
 573         kfree(l2x0_pmu);
 574         l2x0_pmu = NULL;
 575         return ret;
 576 }
 577 device_initcall(l2x0_pmu_init);