drivers/gpu/drm/i915/gt/sysfs_engines.c

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * Copyright © 2019 Intel Corporation
   4  */
   5
   6 #include <linux/kobject.h>
   7 #include <linux/sysfs.h>
   8
   9 #include "i915_drv.h"
  10 #include "intel_engine.h"
  11 #include "intel_engine_heartbeat.h"
  12 #include "sysfs_engines.h"
  13
  14 struct kobj_engine {
  15         struct kobject base;
  16         struct intel_engine_cs *engine;
  17 };
  18
  19 static struct intel_engine_cs *kobj_to_engine(struct kobject *kobj)
  20 {
  21         return container_of(kobj, struct kobj_engine, base)->engine;
  22 }
  23
  24 static ssize_t
  25 name_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
  26 {
  27         return sprintf(buf, "%s\n", kobj_to_engine(kobj)->name);
  28 }
  29
  30 static struct kobj_attribute name_attr =
  31 __ATTR(name, 0444, name_show, NULL);
  32
  33 static ssize_t
  34 class_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
  35 {
  36         return sprintf(buf, "%d\n", kobj_to_engine(kobj)->uabi_class);
  37 }
  38
  39 static struct kobj_attribute class_attr =
  40 __ATTR(class, 0444, class_show, NULL);
  41
  42 static ssize_t
  43 inst_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
  44 {
  45         return sprintf(buf, "%d\n", kobj_to_engine(kobj)->uabi_instance);
  46 }
  47
  48 static struct kobj_attribute inst_attr =
  49 __ATTR(instance, 0444, inst_show, NULL);
  50
  51 static ssize_t
  52 mmio_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
  53 {
  54         return sprintf(buf, "0x%x\n", kobj_to_engine(kobj)->mmio_base);
  55 }
  56
  57 static struct kobj_attribute mmio_attr =
  58 __ATTR(mmio_base, 0444, mmio_show, NULL);
  59
  60 static const char * const vcs_caps[] = {
  61         [ilog2(I915_VIDEO_CLASS_CAPABILITY_HEVC)] = "hevc",
  62         [ilog2(I915_VIDEO_AND_ENHANCE_CLASS_CAPABILITY_SFC)] = "sfc",
  63 };
  64
  65 static const char * const vecs_caps[] = {
  66         [ilog2(I915_VIDEO_AND_ENHANCE_CLASS_CAPABILITY_SFC)] = "sfc",
  67 };
  68
  69 static ssize_t repr_trim(char *buf, ssize_t len)
  70 {
  71         /* Trim off the trailing space and replace with a newline */
  72         if (len > PAGE_SIZE)
  73                 len = PAGE_SIZE;
  74         if (len > 0)
  75                 buf[len - 1] = '\n';
  76
  77         return len;
  78 }
  79
  80 static ssize_t
  81 __caps_show(struct intel_engine_cs *engine,
  82             unsigned long caps, char *buf, bool show_unknown)
  83 {
  84         const char * const *repr;
  85         int count, n;
  86         ssize_t len;
  87
  88         switch (engine->class) {
  89         case VIDEO_DECODE_CLASS:
  90                 repr = vcs_caps;
  91                 count = ARRAY_SIZE(vcs_caps);
  92                 break;
  93
  94         case VIDEO_ENHANCEMENT_CLASS:
  95                 repr = vecs_caps;
  96                 count = ARRAY_SIZE(vecs_caps);
  97                 break;
  98
  99         default:
 100                 repr = NULL;
 101                 count = 0;
 102                 break;
 103         }
 104         GEM_BUG_ON(count > BITS_PER_LONG);
 105
 106         len = 0;
 107         for_each_set_bit(n, &caps, show_unknown ? BITS_PER_LONG : count) {
 108                 if (n >= count || !repr[n]) {
 109                         if (GEM_WARN_ON(show_unknown))
 110                                 len += snprintf(buf + len, PAGE_SIZE - len,
 111                                                 "[%x] ", n);
 112                 } else {
 113                         len += snprintf(buf + len, PAGE_SIZE - len,
 114                                         "%s ", repr[n]);
 115                 }
 116                 if (GEM_WARN_ON(len >= PAGE_SIZE))
 117                         break;
 118         }
 119         return repr_trim(buf, len);
 120 }
 121
 122 static ssize_t
 123 caps_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 124 {
 125         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 126
 127         return __caps_show(engine, engine->uabi_capabilities, buf, true);
 128 }
 129
 130 static struct kobj_attribute caps_attr =
 131 __ATTR(capabilities, 0444, caps_show, NULL);
 132
 133 static ssize_t
 134 all_caps_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 135 {
 136         return __caps_show(kobj_to_engine(kobj), -1, buf, false);
 137 }
 138
 139 static struct kobj_attribute all_caps_attr =
 140 __ATTR(known_capabilities, 0444, all_caps_show, NULL);
 141
 142 static ssize_t
 143 max_spin_store(struct kobject *kobj, struct kobj_attribute *attr,
 144                const char *buf, size_t count)
 145 {
 146         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 147         unsigned long long duration;
 148         int err;
 149
 150         /*
 151          * When waiting for a request, if is it currently being executed
 152          * on the GPU, we busywait for a short while before sleeping. The
 153          * premise is that most requests are short, and if it is already
 154          * executing then there is a good chance that it will complete
 155          * before we can setup the interrupt handler and go to sleep.
 156          * We try to offset the cost of going to sleep, by first spinning
 157          * on the request -- if it completed in less time than it would take
 158          * to go sleep, process the interrupt and return back to the client,
 159          * then we have saved the client some latency, albeit at the cost
 160          * of spinning on an expensive CPU core.
 161          *
 162          * While we try to avoid waiting at all for a request that is unlikely
 163          * to complete, deciding how long it is worth spinning is for is an
 164          * arbitrary decision: trading off power vs latency.
 165          */
 166
 167         err = kstrtoull(buf, 0, &duration);
 168         if (err)
 169                 return err;
 170
 171         if (duration > jiffies_to_nsecs(2))
 172                 return -EINVAL;
 173
 174         WRITE_ONCE(engine->props.max_busywait_duration_ns, duration);
 175
 176         return count;
 177 }
 178
 179 static ssize_t
 180 max_spin_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 181 {
 182         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 183
 184         return sprintf(buf, "%lu\n", engine->props.max_busywait_duration_ns);
 185 }
 186
 187 static struct kobj_attribute max_spin_attr =
 188 __ATTR(max_busywait_duration_ns, 0644, max_spin_show, max_spin_store);
 189
 190 static ssize_t
 191 max_spin_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 192 {
 193         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 194
 195         return sprintf(buf, "%lu\n", engine->defaults.max_busywait_duration_ns);
 196 }
 197
 198 static struct kobj_attribute max_spin_def =
 199 __ATTR(max_busywait_duration_ns, 0444, max_spin_default, NULL);
 200
 201 static ssize_t
 202 timeslice_store(struct kobject *kobj, struct kobj_attribute *attr,
 203                 const char *buf, size_t count)
 204 {
 205         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 206         unsigned long long duration;
 207         int err;
 208
 209         /*
 210          * Execlists uses a scheduling quantum (a timeslice) to alternate
 211          * execution between ready-to-run contexts of equal priority. This
 212          * ensures that all users (though only if they of equal importance)
 213          * have the opportunity to run and prevents livelocks where contexts
 214          * may have implicit ordering due to userspace semaphores.
 215          */
 216
 217         err = kstrtoull(buf, 0, &duration);
 218         if (err)
 219                 return err;
 220
 221         if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
 222                 return -EINVAL;
 223
 224         WRITE_ONCE(engine->props.timeslice_duration_ms, duration);
 225
 226         if (execlists_active(&engine->execlists))
 227                 set_timer_ms(&engine->execlists.timer, duration);
 228
 229         return count;
 230 }
 231
 232 static ssize_t
 233 timeslice_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 234 {
 235         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 236
 237         return sprintf(buf, "%lu\n", engine->props.timeslice_duration_ms);
 238 }
 239
 240 static struct kobj_attribute timeslice_duration_attr =
 241 __ATTR(timeslice_duration_ms, 0644, timeslice_show, timeslice_store);
 242
 243 static ssize_t
 244 timeslice_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 245 {
 246         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 247
 248         return sprintf(buf, "%lu\n", engine->defaults.timeslice_duration_ms);
 249 }
 250
 251 static struct kobj_attribute timeslice_duration_def =
 252 __ATTR(timeslice_duration_ms, 0444, timeslice_default, NULL);
 253
 254 static ssize_t
 255 stop_store(struct kobject *kobj, struct kobj_attribute *attr,
 256            const char *buf, size_t count)
 257 {
 258         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 259         unsigned long long duration;
 260         int err;
 261
 262         /*
 263          * When we allow ourselves to sleep before a GPU reset after disabling
 264          * submission, even for a few milliseconds, gives an innocent context
 265          * the opportunity to clear the GPU before the reset occurs. However,
 266          * how long to sleep depends on the typical non-preemptible duration
 267          * (a similar problem to determining the ideal preempt-reset timeout
 268          * or even the heartbeat interval).
 269          */
 270
 271         err = kstrtoull(buf, 0, &duration);
 272         if (err)
 273                 return err;
 274
 275         if (duration > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
 276                 return -EINVAL;
 277
 278         WRITE_ONCE(engine->props.stop_timeout_ms, duration);
 279         return count;
 280 }
 281
 282 static ssize_t
 283 stop_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 284 {
 285         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 286
 287         return sprintf(buf, "%lu\n", engine->props.stop_timeout_ms);
 288 }
 289
 290 static struct kobj_attribute stop_timeout_attr =
 291 __ATTR(stop_timeout_ms, 0644, stop_show, stop_store);
 292
 293 static ssize_t
 294 stop_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 295 {
 296         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 297
 298         return sprintf(buf, "%lu\n", engine->defaults.stop_timeout_ms);
 299 }
 300
 301 static struct kobj_attribute stop_timeout_def =
 302 __ATTR(stop_timeout_ms, 0444, stop_default, NULL);
 303
 304 static ssize_t
 305 preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr,
 306                       const char *buf, size_t count)
 307 {
 308         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 309         unsigned long long timeout;
 310         int err;
 311
 312         /*
 313          * After initialising a preemption request, we give the current
 314          * resident a small amount of time to vacate the GPU. The preemption
 315          * request is for a higher priority context and should be immediate to
 316          * maintain high quality of service (and avoid priority inversion).
 317          * However, the preemption granularity of the GPU can be quite coarse
 318          * and so we need a compromise.
 319          */
 320
 321         err = kstrtoull(buf, 0, &timeout);
 322         if (err)
 323                 return err;
 324
 325         if (timeout > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
 326                 return -EINVAL;
 327
 328         WRITE_ONCE(engine->props.preempt_timeout_ms, timeout);
 329
 330         if (READ_ONCE(engine->execlists.pending[0]))
 331                 set_timer_ms(&engine->execlists.preempt, timeout);
 332
 333         return count;
 334 }
 335
 336 static ssize_t
 337 preempt_timeout_show(struct kobject *kobj, struct kobj_attribute *attr,
 338                      char *buf)
 339 {
 340         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 341
 342         return sprintf(buf, "%lu\n", engine->props.preempt_timeout_ms);
 343 }
 344
 345 static struct kobj_attribute preempt_timeout_attr =
 346 __ATTR(preempt_timeout_ms, 0644, preempt_timeout_show, preempt_timeout_store);
 347
 348 static ssize_t
 349 preempt_timeout_default(struct kobject *kobj, struct kobj_attribute *attr,
 350                         char *buf)
 351 {
 352         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 353
 354         return sprintf(buf, "%lu\n", engine->defaults.preempt_timeout_ms);
 355 }
 356
 357 static struct kobj_attribute preempt_timeout_def =
 358 __ATTR(preempt_timeout_ms, 0444, preempt_timeout_default, NULL);
 359
 360 static ssize_t
 361 heartbeat_store(struct kobject *kobj, struct kobj_attribute *attr,
 362                 const char *buf, size_t count)
 363 {
 364         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 365         unsigned long long delay;
 366         int err;
 367
 368         /*
 369          * We monitor the health of the system via periodic heartbeat pulses.
 370          * The pulses also provide the opportunity to perform garbage
 371          * collection.  However, we interpret an incomplete pulse (a missed
 372          * heartbeat) as an indication that the system is no longer responsive,
 373          * i.e. hung, and perform an engine or full GPU reset. Given that the
 374          * preemption granularity can be very coarse on a system, the optimal
 375          * value for any workload is unknowable!
 376          */
 377
 378         err = kstrtoull(buf, 0, &delay);
 379         if (err)
 380                 return err;
 381
 382         if (delay >= jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT))
 383                 return -EINVAL;
 384
 385         err = intel_engine_set_heartbeat(engine, delay);
 386         if (err)
 387                 return err;
 388
 389         return count;
 390 }
 391
 392 static ssize_t
 393 heartbeat_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 394 {
 395         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 396
 397         return sprintf(buf, "%lu\n", engine->props.heartbeat_interval_ms);
 398 }
 399
 400 static struct kobj_attribute heartbeat_interval_attr =
 401 __ATTR(heartbeat_interval_ms, 0644, heartbeat_show, heartbeat_store);
 402
 403 static ssize_t
 404 heartbeat_default(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 405 {
 406         struct intel_engine_cs *engine = kobj_to_engine(kobj);
 407
 408         return sprintf(buf, "%lu\n", engine->defaults.heartbeat_interval_ms);
 409 }
 410
 411 static struct kobj_attribute heartbeat_interval_def =
 412 __ATTR(heartbeat_interval_ms, 0444, heartbeat_default, NULL);
 413
 414 static void kobj_engine_release(struct kobject *kobj)
 415 {
 416         kfree(kobj);
 417 }
 418
 419 static struct kobj_type kobj_engine_type = {
 420         .release = kobj_engine_release,
 421         .sysfs_ops = &kobj_sysfs_ops
 422 };
 423
 424 static struct kobject *
 425 kobj_engine(struct kobject *dir, struct intel_engine_cs *engine)
 426 {
 427         struct kobj_engine *ke;
 428
 429         ke = kzalloc(sizeof(*ke), GFP_KERNEL);
 430         if (!ke)
 431                 return NULL;
 432
 433         kobject_init(&ke->base, &kobj_engine_type);
 434         ke->engine = engine;
 435
 436         if (kobject_add(&ke->base, dir, "%s", engine->name)) {
 437                 kobject_put(&ke->base);
 438                 return NULL;
 439         }
 440
 441         /* xfer ownership to sysfs tree */
 442         return &ke->base;
 443 }
 444
 445 static void add_defaults(struct kobj_engine *parent)
 446 {
 447         static const struct attribute *files[] = {
 448                 &max_spin_def.attr,
 449                 &stop_timeout_def.attr,
 450 #if CONFIG_DRM_I915_HEARTBEAT_INTERVAL
 451                 &heartbeat_interval_def.attr,
 452 #endif
 453                 NULL
 454         };
 455         struct kobj_engine *ke;
 456
 457         ke = kzalloc(sizeof(*ke), GFP_KERNEL);
 458         if (!ke)
 459                 return;
 460
 461         kobject_init(&ke->base, &kobj_engine_type);
 462         ke->engine = parent->engine;
 463
 464         if (kobject_add(&ke->base, &parent->base, "%s", ".defaults")) {
 465                 kobject_put(&ke->base);
 466                 return;
 467         }
 468
 469         if (sysfs_create_files(&ke->base, files))
 470                 return;
 471
 472         if (intel_engine_has_timeslices(ke->engine) &&
 473             sysfs_create_file(&ke->base, &timeslice_duration_def.attr))
 474                 return;
 475
 476         if (intel_engine_has_preempt_reset(ke->engine) &&
 477             sysfs_create_file(&ke->base, &preempt_timeout_def.attr))
 478                 return;
 479 }
 480
 481 void intel_engines_add_sysfs(struct drm_i915_private *i915)
 482 {
 483         static const struct attribute *files[] = {
 484                 &name_attr.attr,
 485                 &class_attr.attr,
 486                 &inst_attr.attr,
 487                 &mmio_attr.attr,
 488                 &caps_attr.attr,
 489                 &all_caps_attr.attr,
 490                 &max_spin_attr.attr,
 491                 &stop_timeout_attr.attr,
 492 #if CONFIG_DRM_I915_HEARTBEAT_INTERVAL
 493                 &heartbeat_interval_attr.attr,
 494 #endif
 495                 NULL
 496         };
 497
 498         struct device *kdev = i915->drm.primary->kdev;
 499         struct intel_engine_cs *engine;
 500         struct kobject *dir;
 501
 502         dir = kobject_create_and_add("engine", &kdev->kobj);
 503         if (!dir)
 504                 return;
 505
 506         for_each_uabi_engine(engine, i915) {
 507                 struct kobject *kobj;
 508
 509                 kobj = kobj_engine(dir, engine);
 510                 if (!kobj)
 511                         goto err_engine;
 512
 513                 if (sysfs_create_files(kobj, files))
 514                         goto err_object;
 515
 516                 if (intel_engine_has_timeslices(engine) &&
 517                     sysfs_create_file(kobj, &timeslice_duration_attr.attr))
 518                         goto err_engine;
 519
 520                 if (intel_engine_has_preempt_reset(engine) &&
 521                     sysfs_create_file(kobj, &preempt_timeout_attr.attr))
 522                         goto err_engine;
 523
 524                 add_defaults(container_of(kobj, struct kobj_engine, base));
 525
 526                 if (0) {
 527 err_object:
 528                         kobject_put(kobj);
 529 err_engine:
 530                         dev_err(kdev, "Failed to add sysfs engine '%s'\n",
 531                                 engine->name);
 532                         break;
 533                 }
 534         }
 535 }