tools/perf/arch/arm/util/cs-etm.c

   1 /*
   2  * Copyright(C) 2015 Linaro Limited. All rights reserved.
   3  * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <api/fs/fs.h>
  19 #include <linux/bitops.h>
  20 #include <linux/compiler.h>
  21 #include <linux/coresight-pmu.h>
  22 #include <linux/kernel.h>
  23 #include <linux/log2.h>
  24 #include <linux/types.h>
  25
  26 #include "cs-etm.h"
  27 #include "../../perf.h"
  28 #include "../../util/auxtrace.h"
  29 #include "../../util/cpumap.h"
  30 #include "../../util/evlist.h"
  31 #include "../../util/evsel.h"
  32 #include "../../util/pmu.h"
  33 #include "../../util/thread_map.h"
  34 #include "../../util/cs-etm.h"
  35
  36 #include <stdlib.h>
  37 #include <sys/stat.h>
  38
  39 #define ENABLE_SINK_MAX 128
  40 #define CS_BUS_DEVICE_PATH "/bus/coresight/devices/"
  41
  42 struct cs_etm_recording {
  43         struct auxtrace_record  itr;
  44         struct perf_pmu         *cs_etm_pmu;
  45         struct perf_evlist      *evlist;
  46         bool                    snapshot_mode;
  47         size_t                  snapshot_size;
  48 };
  49
  50 static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu);
  51
  52 static int cs_etm_parse_snapshot_options(struct auxtrace_record *itr,
  53                                          struct record_opts *opts,
  54                                          const char *str)
  55 {
  56         struct cs_etm_recording *ptr =
  57                                 container_of(itr, struct cs_etm_recording, itr);
  58         unsigned long long snapshot_size = 0;
  59         char *endptr;
  60
  61         if (str) {
  62                 snapshot_size = strtoull(str, &endptr, 0);
  63                 if (*endptr || snapshot_size > SIZE_MAX)
  64                         return -1;
  65         }
  66
  67         opts->auxtrace_snapshot_mode = true;
  68         opts->auxtrace_snapshot_size = snapshot_size;
  69         ptr->snapshot_size = snapshot_size;
  70
  71         return 0;
  72 }
  73
  74 static int cs_etm_recording_options(struct auxtrace_record *itr,
  75                                     struct perf_evlist *evlist,
  76                                     struct record_opts *opts)
  77 {
  78         struct cs_etm_recording *ptr =
  79                                 container_of(itr, struct cs_etm_recording, itr);
  80         struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
  81         struct perf_evsel *evsel, *cs_etm_evsel = NULL;
  82         const struct cpu_map *cpus = evlist->cpus;
  83         bool privileged = (geteuid() == 0 || perf_event_paranoid() < 0);
  84
  85         ptr->evlist = evlist;
  86         ptr->snapshot_mode = opts->auxtrace_snapshot_mode;
  87
  88         evlist__for_each_entry(evlist, evsel) {
  89                 if (evsel->attr.type == cs_etm_pmu->type) {
  90                         if (cs_etm_evsel) {
  91                                 pr_err("There may be only one %s event\n",
  92                                        CORESIGHT_ETM_PMU_NAME);
  93                                 return -EINVAL;
  94                         }
  95                         evsel->attr.freq = 0;
  96                         evsel->attr.sample_period = 1;
  97                         cs_etm_evsel = evsel;
  98                         opts->full_auxtrace = true;
  99                 }
 100         }
 101
 102         /* no need to continue if at least one event of interest was found */
 103         if (!cs_etm_evsel)
 104                 return 0;
 105
 106         if (opts->use_clockid) {
 107                 pr_err("Cannot use clockid (-k option) with %s\n",
 108                        CORESIGHT_ETM_PMU_NAME);
 109                 return -EINVAL;
 110         }
 111
 112         /* we are in snapshot mode */
 113         if (opts->auxtrace_snapshot_mode) {
 114                 /*
 115                  * No size were given to '-S' or '-m,', so go with
 116                  * the default
 117                  */
 118                 if (!opts->auxtrace_snapshot_size &&
 119                     !opts->auxtrace_mmap_pages) {
 120                         if (privileged) {
 121                                 opts->auxtrace_mmap_pages = MiB(4) / page_size;
 122                         } else {
 123                                 opts->auxtrace_mmap_pages =
 124                                                         KiB(128) / page_size;
 125                                 if (opts->mmap_pages == UINT_MAX)
 126                                         opts->mmap_pages = KiB(256) / page_size;
 127                         }
 128                 } else if (!opts->auxtrace_mmap_pages && !privileged &&
 129                                                 opts->mmap_pages == UINT_MAX) {
 130                         opts->mmap_pages = KiB(256) / page_size;
 131                 }
 132
 133                 /*
 134                  * '-m,xyz' was specified but no snapshot size, so make the
 135                  * snapshot size as big as the auxtrace mmap area.
 136                  */
 137                 if (!opts->auxtrace_snapshot_size) {
 138                         opts->auxtrace_snapshot_size =
 139                                 opts->auxtrace_mmap_pages * (size_t)page_size;
 140                 }
 141
 142                 /*
 143                  * -Sxyz was specified but no auxtrace mmap area, so make the
 144                  * auxtrace mmap area big enough to fit the requested snapshot
 145                  * size.
 146                  */
 147                 if (!opts->auxtrace_mmap_pages) {
 148                         size_t sz = opts->auxtrace_snapshot_size;
 149
 150                         sz = round_up(sz, page_size) / page_size;
 151                         opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
 152                 }
 153
 154                 /* Snapshost size can't be bigger than the auxtrace area */
 155                 if (opts->auxtrace_snapshot_size >
 156                                 opts->auxtrace_mmap_pages * (size_t)page_size) {
 157                         pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
 158                                opts->auxtrace_snapshot_size,
 159                                opts->auxtrace_mmap_pages * (size_t)page_size);
 160                         return -EINVAL;
 161                 }
 162
 163                 /* Something went wrong somewhere - this shouldn't happen */
 164                 if (!opts->auxtrace_snapshot_size ||
 165                     !opts->auxtrace_mmap_pages) {
 166                         pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
 167                         return -EINVAL;
 168                 }
 169         }
 170
 171         /* We are in full trace mode but '-m,xyz' wasn't specified */
 172         if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
 173                 if (privileged) {
 174                         opts->auxtrace_mmap_pages = MiB(4) / page_size;
 175                 } else {
 176                         opts->auxtrace_mmap_pages = KiB(128) / page_size;
 177                         if (opts->mmap_pages == UINT_MAX)
 178                                 opts->mmap_pages = KiB(256) / page_size;
 179                 }
 180
 181         }
 182
 183         /* Validate auxtrace_mmap_pages provided by user */
 184         if (opts->auxtrace_mmap_pages) {
 185                 unsigned int max_page = (KiB(128) / page_size);
 186                 size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
 187
 188                 if (!privileged &&
 189                     opts->auxtrace_mmap_pages > max_page) {
 190                         opts->auxtrace_mmap_pages = max_page;
 191                         pr_err("auxtrace too big, truncating to %d\n",
 192                                max_page);
 193                 }
 194
 195                 if (!is_power_of_2(sz)) {
 196                         pr_err("Invalid mmap size for %s: must be a power of 2\n",
 197                                CORESIGHT_ETM_PMU_NAME);
 198                         return -EINVAL;
 199                 }
 200         }
 201
 202         if (opts->auxtrace_snapshot_mode)
 203                 pr_debug2("%s snapshot size: %zu\n", CORESIGHT_ETM_PMU_NAME,
 204                           opts->auxtrace_snapshot_size);
 205
 206         /*
 207          * To obtain the auxtrace buffer file descriptor, the auxtrace
 208          * event must come first.
 209          */
 210         perf_evlist__to_front(evlist, cs_etm_evsel);
 211
 212         /*
 213          * In the case of per-cpu mmaps, we need the CPU on the
 214          * AUX event.
 215          */
 216         if (!cpu_map__empty(cpus))
 217                 perf_evsel__set_sample_bit(cs_etm_evsel, CPU);
 218
 219         /* Add dummy event to keep tracking */
 220         if (opts->full_auxtrace) {
 221                 struct perf_evsel *tracking_evsel;
 222                 int err;
 223
 224                 err = parse_events(evlist, "dummy:u", NULL);
 225                 if (err)
 226                         return err;
 227
 228                 tracking_evsel = perf_evlist__last(evlist);
 229                 perf_evlist__set_tracking_event(evlist, tracking_evsel);
 230
 231                 tracking_evsel->attr.freq = 0;
 232                 tracking_evsel->attr.sample_period = 1;
 233
 234                 /* In per-cpu case, always need the time of mmap events etc */
 235                 if (!cpu_map__empty(cpus))
 236                         perf_evsel__set_sample_bit(tracking_evsel, TIME);
 237         }
 238
 239         return 0;
 240 }
 241
 242 static u64 cs_etm_get_config(struct auxtrace_record *itr)
 243 {
 244         u64 config = 0;
 245         struct cs_etm_recording *ptr =
 246                         container_of(itr, struct cs_etm_recording, itr);
 247         struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
 248         struct perf_evlist *evlist = ptr->evlist;
 249         struct perf_evsel *evsel;
 250
 251         evlist__for_each_entry(evlist, evsel) {
 252                 if (evsel->attr.type == cs_etm_pmu->type) {
 253                         /*
 254                          * Variable perf_event_attr::config is assigned to
 255                          * ETMv3/PTM.  The bit fields have been made to match
 256                          * the ETMv3.5 ETRMCR register specification.  See the
 257                          * PMU_FORMAT_ATTR() declarations in
 258                          * drivers/hwtracing/coresight/coresight-perf.c for
 259                          * details.
 260                          */
 261                         config = evsel->attr.config;
 262                         break;
 263                 }
 264         }
 265
 266         return config;
 267 }
 268
 269 #ifndef BIT
 270 #define BIT(N) (1UL << (N))
 271 #endif
 272
 273 static u64 cs_etmv4_get_config(struct auxtrace_record *itr)
 274 {
 275         u64 config = 0;
 276         u64 config_opts = 0;
 277
 278         /*
 279          * The perf event variable config bits represent both
 280          * the command line options and register programming
 281          * bits in ETMv3/PTM. For ETMv4 we must remap options
 282          * to real bits
 283          */
 284         config_opts = cs_etm_get_config(itr);
 285         if (config_opts & BIT(ETM_OPT_CYCACC))
 286                 config |= BIT(ETM4_CFG_BIT_CYCACC);
 287         if (config_opts & BIT(ETM_OPT_TS))
 288                 config |= BIT(ETM4_CFG_BIT_TS);
 289         if (config_opts & BIT(ETM_OPT_RETSTK))
 290                 config |= BIT(ETM4_CFG_BIT_RETSTK);
 291
 292         return config;
 293 }
 294
 295 static size_t
 296 cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
 297                       struct perf_evlist *evlist __maybe_unused)
 298 {
 299         int i;
 300         int etmv3 = 0, etmv4 = 0;
 301         const struct cpu_map *cpus = evlist->cpus;
 302
 303         /* cpu map is not empty, we have specific CPUs to work with */
 304         if (!cpu_map__empty(cpus)) {
 305                 for (i = 0; i < cpu_map__nr(cpus); i++) {
 306                         if (cs_etm_is_etmv4(itr, cpus->map[i]))
 307                                 etmv4++;
 308                         else
 309                                 etmv3++;
 310                 }
 311         } else {
 312                 /* get configuration for all CPUs in the system */
 313                 for (i = 0; i < cpu__max_cpu(); i++) {
 314                         if (cs_etm_is_etmv4(itr, i))
 315                                 etmv4++;
 316                         else
 317                                 etmv3++;
 318                 }
 319         }
 320
 321         return (CS_ETM_HEADER_SIZE +
 322                (etmv4 * CS_ETMV4_PRIV_SIZE) +
 323                (etmv3 * CS_ETMV3_PRIV_SIZE));
 324 }
 325
 326 static const char *metadata_etmv3_ro[CS_ETM_PRIV_MAX] = {
 327         [CS_ETM_ETMCCER]        = "mgmt/etmccer",
 328         [CS_ETM_ETMIDR]         = "mgmt/etmidr",
 329 };
 330
 331 static const char *metadata_etmv4_ro[CS_ETMV4_PRIV_MAX] = {
 332         [CS_ETMV4_TRCIDR0]              = "trcidr/trcidr0",
 333         [CS_ETMV4_TRCIDR1]              = "trcidr/trcidr1",
 334         [CS_ETMV4_TRCIDR2]              = "trcidr/trcidr2",
 335         [CS_ETMV4_TRCIDR8]              = "trcidr/trcidr8",
 336         [CS_ETMV4_TRCAUTHSTATUS]        = "mgmt/trcauthstatus",
 337 };
 338
 339 static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu)
 340 {
 341         bool ret = false;
 342         char path[PATH_MAX];
 343         int scan;
 344         unsigned int val;
 345         struct cs_etm_recording *ptr =
 346                         container_of(itr, struct cs_etm_recording, itr);
 347         struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
 348
 349         /* Take any of the RO files for ETMv4 and see if it present */
 350         snprintf(path, PATH_MAX, "cpu%d/%s",
 351                  cpu, metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);
 352         scan = perf_pmu__scan_file(cs_etm_pmu, path, "%x", &val);
 353
 354         /* The file was read successfully, we have a winner */
 355         if (scan == 1)
 356                 ret = true;
 357
 358         return ret;
 359 }
 360
 361 static int cs_etm_get_ro(struct perf_pmu *pmu, int cpu, const char *path)
 362 {
 363         char pmu_path[PATH_MAX];
 364         int scan;
 365         unsigned int val = 0;
 366
 367         /* Get RO metadata from sysfs */
 368         snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu, path);
 369
 370         scan = perf_pmu__scan_file(pmu, pmu_path, "%x", &val);
 371         if (scan != 1)
 372                 pr_err("%s: error reading: %s\n", __func__, pmu_path);
 373
 374         return val;
 375 }
 376
 377 static void cs_etm_get_metadata(int cpu, u32 *offset,
 378                                 struct auxtrace_record *itr,
 379                                 struct auxtrace_info_event *info)
 380 {
 381         u32 increment;
 382         u64 magic;
 383         struct cs_etm_recording *ptr =
 384                         container_of(itr, struct cs_etm_recording, itr);
 385         struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
 386
 387         /* first see what kind of tracer this cpu is affined to */
 388         if (cs_etm_is_etmv4(itr, cpu)) {
 389                 magic = __perf_cs_etmv4_magic;
 390                 /* Get trace configuration register */
 391                 info->priv[*offset + CS_ETMV4_TRCCONFIGR] =
 392                                                 cs_etmv4_get_config(itr);
 393                 /* Get traceID from the framework */
 394                 info->priv[*offset + CS_ETMV4_TRCTRACEIDR] =
 395                                                 coresight_get_trace_id(cpu);
 396                 /* Get read-only information from sysFS */
 397                 info->priv[*offset + CS_ETMV4_TRCIDR0] =
 398                         cs_etm_get_ro(cs_etm_pmu, cpu,
 399                                       metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);
 400                 info->priv[*offset + CS_ETMV4_TRCIDR1] =
 401                         cs_etm_get_ro(cs_etm_pmu, cpu,
 402                                       metadata_etmv4_ro[CS_ETMV4_TRCIDR1]);
 403                 info->priv[*offset + CS_ETMV4_TRCIDR2] =
 404                         cs_etm_get_ro(cs_etm_pmu, cpu,
 405                                       metadata_etmv4_ro[CS_ETMV4_TRCIDR2]);
 406                 info->priv[*offset + CS_ETMV4_TRCIDR8] =
 407                         cs_etm_get_ro(cs_etm_pmu, cpu,
 408                                       metadata_etmv4_ro[CS_ETMV4_TRCIDR8]);
 409                 info->priv[*offset + CS_ETMV4_TRCAUTHSTATUS] =
 410                         cs_etm_get_ro(cs_etm_pmu, cpu,
 411                                       metadata_etmv4_ro
 412                                       [CS_ETMV4_TRCAUTHSTATUS]);
 413
 414                 /* How much space was used */
 415                 increment = CS_ETMV4_PRIV_MAX;
 416         } else {
 417                 magic = __perf_cs_etmv3_magic;
 418                 /* Get configuration register */
 419                 info->priv[*offset + CS_ETM_ETMCR] = cs_etm_get_config(itr);
 420                 /* Get traceID from the framework */
 421                 info->priv[*offset + CS_ETM_ETMTRACEIDR] =
 422                                                 coresight_get_trace_id(cpu);
 423                 /* Get read-only information from sysFS */
 424                 info->priv[*offset + CS_ETM_ETMCCER] =
 425                         cs_etm_get_ro(cs_etm_pmu, cpu,
 426                                       metadata_etmv3_ro[CS_ETM_ETMCCER]);
 427                 info->priv[*offset + CS_ETM_ETMIDR] =
 428                         cs_etm_get_ro(cs_etm_pmu, cpu,
 429                                       metadata_etmv3_ro[CS_ETM_ETMIDR]);
 430
 431                 /* How much space was used */
 432                 increment = CS_ETM_PRIV_MAX;
 433         }
 434
 435         /* Build generic header portion */
 436         info->priv[*offset + CS_ETM_MAGIC] = magic;
 437         info->priv[*offset + CS_ETM_CPU] = cpu;
 438         /* Where the next CPU entry should start from */
 439         *offset += increment;
 440 }
 441
 442 static int cs_etm_info_fill(struct auxtrace_record *itr,
 443                             struct perf_session *session,
 444                             struct auxtrace_info_event *info,
 445                             size_t priv_size)
 446 {
 447         int i;
 448         u32 offset;
 449         u64 nr_cpu, type;
 450         const struct cpu_map *cpus = session->evlist->cpus;
 451         struct cs_etm_recording *ptr =
 452                         container_of(itr, struct cs_etm_recording, itr);
 453         struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
 454
 455         if (priv_size != cs_etm_info_priv_size(itr, session->evlist))
 456                 return -EINVAL;
 457
 458         if (!session->evlist->nr_mmaps)
 459                 return -EINVAL;
 460
 461         /* If the cpu_map is empty all CPUs are involved */
 462         nr_cpu = cpu_map__empty(cpus) ? cpu__max_cpu() : cpu_map__nr(cpus);
 463         /* Get PMU type as dynamically assigned by the core */
 464         type = cs_etm_pmu->type;
 465
 466         /* First fill out the session header */
 467         info->type = PERF_AUXTRACE_CS_ETM;
 468         info->priv[CS_HEADER_VERSION_0] = 0;
 469         info->priv[CS_PMU_TYPE_CPUS] = type << 32;
 470         info->priv[CS_PMU_TYPE_CPUS] |= nr_cpu;
 471         info->priv[CS_ETM_SNAPSHOT] = ptr->snapshot_mode;
 472
 473         offset = CS_ETM_SNAPSHOT + 1;
 474
 475         /* cpu map is not empty, we have specific CPUs to work with */
 476         if (!cpu_map__empty(cpus)) {
 477                 for (i = 0; i < cpu_map__nr(cpus) && offset < priv_size; i++)
 478                         cs_etm_get_metadata(cpus->map[i], &offset, itr, info);
 479         } else {
 480                 /* get configuration for all CPUs in the system */
 481                 for (i = 0; i < cpu__max_cpu(); i++)
 482                         cs_etm_get_metadata(i, &offset, itr, info);
 483         }
 484
 485         return 0;
 486 }
 487
 488 static int cs_etm_find_snapshot(struct auxtrace_record *itr __maybe_unused,
 489                                 int idx, struct auxtrace_mmap *mm,
 490                                 unsigned char *data __maybe_unused,
 491                                 u64 *head, u64 *old)
 492 {
 493         pr_debug3("%s: mmap index %d old head %zu new head %zu size %zu\n",
 494                   __func__, idx, (size_t)*old, (size_t)*head, mm->len);
 495
 496         *old = *head;
 497         *head += mm->len;
 498
 499         return 0;
 500 }
 501
 502 static int cs_etm_snapshot_start(struct auxtrace_record *itr)
 503 {
 504         struct cs_etm_recording *ptr =
 505                         container_of(itr, struct cs_etm_recording, itr);
 506         struct perf_evsel *evsel;
 507
 508         evlist__for_each_entry(ptr->evlist, evsel) {
 509                 if (evsel->attr.type == ptr->cs_etm_pmu->type)
 510                         return perf_evsel__disable(evsel);
 511         }
 512         return -EINVAL;
 513 }
 514
 515 static int cs_etm_snapshot_finish(struct auxtrace_record *itr)
 516 {
 517         struct cs_etm_recording *ptr =
 518                         container_of(itr, struct cs_etm_recording, itr);
 519         struct perf_evsel *evsel;
 520
 521         evlist__for_each_entry(ptr->evlist, evsel) {
 522                 if (evsel->attr.type == ptr->cs_etm_pmu->type)
 523                         return perf_evsel__enable(evsel);
 524         }
 525         return -EINVAL;
 526 }
 527
 528 static u64 cs_etm_reference(struct auxtrace_record *itr __maybe_unused)
 529 {
 530         return (((u64) rand() <<  0) & 0x00000000FFFFFFFFull) |
 531                 (((u64) rand() << 32) & 0xFFFFFFFF00000000ull);
 532 }
 533
 534 static void cs_etm_recording_free(struct auxtrace_record *itr)
 535 {
 536         struct cs_etm_recording *ptr =
 537                         container_of(itr, struct cs_etm_recording, itr);
 538         free(ptr);
 539 }
 540
 541 static int cs_etm_read_finish(struct auxtrace_record *itr, int idx)
 542 {
 543         struct cs_etm_recording *ptr =
 544                         container_of(itr, struct cs_etm_recording, itr);
 545         struct perf_evsel *evsel;
 546
 547         evlist__for_each_entry(ptr->evlist, evsel) {
 548                 if (evsel->attr.type == ptr->cs_etm_pmu->type)
 549                         return perf_evlist__enable_event_idx(ptr->evlist,
 550                                                              evsel, idx);
 551         }
 552
 553         return -EINVAL;
 554 }
 555
 556 struct auxtrace_record *cs_etm_record_init(int *err)
 557 {
 558         struct perf_pmu *cs_etm_pmu;
 559         struct cs_etm_recording *ptr;
 560
 561         cs_etm_pmu = perf_pmu__find(CORESIGHT_ETM_PMU_NAME);
 562
 563         if (!cs_etm_pmu) {
 564                 *err = -EINVAL;
 565                 goto out;
 566         }
 567
 568         ptr = zalloc(sizeof(struct cs_etm_recording));
 569         if (!ptr) {
 570                 *err = -ENOMEM;
 571                 goto out;
 572         }
 573
 574         ptr->cs_etm_pmu                 = cs_etm_pmu;
 575         ptr->itr.parse_snapshot_options = cs_etm_parse_snapshot_options;
 576         ptr->itr.recording_options      = cs_etm_recording_options;
 577         ptr->itr.info_priv_size         = cs_etm_info_priv_size;
 578         ptr->itr.info_fill              = cs_etm_info_fill;
 579         ptr->itr.find_snapshot          = cs_etm_find_snapshot;
 580         ptr->itr.snapshot_start         = cs_etm_snapshot_start;
 581         ptr->itr.snapshot_finish        = cs_etm_snapshot_finish;
 582         ptr->itr.reference              = cs_etm_reference;
 583         ptr->itr.free                   = cs_etm_recording_free;
 584         ptr->itr.read_finish            = cs_etm_read_finish;
 585
 586         *err = 0;
 587         return &ptr->itr;
 588 out:
 589         return NULL;
 590 }
 591
 592 static FILE *cs_device__open_file(const char *name)
 593 {
 594         struct stat st;
 595         char path[PATH_MAX];
 596         const char *sysfs;
 597
 598         sysfs = sysfs__mountpoint();
 599         if (!sysfs)
 600                 return NULL;
 601
 602         snprintf(path, PATH_MAX,
 603                  "%s" CS_BUS_DEVICE_PATH "%s", sysfs, name);
 604
 605         if (stat(path, &st) < 0)
 606                 return NULL;
 607
 608         return fopen(path, "w");
 609
 610 }
 611
 612 static int __printf(2, 3) cs_device__print_file(const char *name, const char *fmt, ...)
 613 {
 614         va_list args;
 615         FILE *file;
 616         int ret = -EINVAL;
 617
 618         va_start(args, fmt);
 619         file = cs_device__open_file(name);
 620         if (file) {
 621                 ret = vfprintf(file, fmt, args);
 622                 fclose(file);
 623         }
 624         va_end(args);
 625         return ret;
 626 }
 627
 628 int cs_etm_set_drv_config(struct perf_evsel_config_term *term)
 629 {
 630         int ret;
 631         char enable_sink[ENABLE_SINK_MAX];
 632
 633         snprintf(enable_sink, ENABLE_SINK_MAX, "%s/%s",
 634                  term->val.drv_cfg, "enable_sink");
 635
 636         ret = cs_device__print_file(enable_sink, "%d", 1);
 637         if (ret < 0)
 638                 return ret;
 639
 640         return 0;
 641 }