drivers/hwtracing/coresight/coresight-core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2012, The Linux Foundation. All rights reserved.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/init.h>
   8 #include <linux/types.h>
   9 #include <linux/device.h>
  10 #include <linux/io.h>
  11 #include <linux/idr.h>
  12 #include <linux/err.h>
  13 #include <linux/export.h>
  14 #include <linux/slab.h>
  15 #include <linux/stringhash.h>
  16 #include <linux/mutex.h>
  17 #include <linux/clk.h>
  18 #include <linux/coresight.h>
  19 #include <linux/of_platform.h>
  20 #include <linux/delay.h>
  21 #include <linux/pm_runtime.h>
  22
  23 #include "coresight-etm-perf.h"
  24 #include "coresight-priv.h"
  25 #include "coresight-syscfg.h"
  26
  27 static DEFINE_MUTEX(coresight_mutex);
  28 static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
  29
  30 /*
  31  * Use IDR to map the hash of the source's device name
  32  * to the pointer of path for the source. The idr is for
  33  * the sources which aren't associated with CPU.
  34  */
  35 static DEFINE_IDR(path_idr);
  36
  37 /**
  38  * struct coresight_node - elements of a path, from source to sink
  39  * @csdev:      Address of an element.
  40  * @link:       hook to the list.
  41  */
  42 struct coresight_node {
  43         struct coresight_device *csdev;
  44         struct list_head link;
  45 };
  46
  47 /*
  48  * When operating Coresight drivers from the sysFS interface, only a single
  49  * path can exist from a tracer (associated to a CPU) to a sink.
  50  */
  51 static DEFINE_PER_CPU(struct list_head *, tracer_path);
  52
  53 /*
  54  * When losing synchronisation a new barrier packet needs to be inserted at the
  55  * beginning of the data collected in a buffer.  That way the decoder knows that
  56  * it needs to look for another sync sequence.
  57  */
  58 const u32 coresight_barrier_pkt[4] = {0x7fffffff, 0x7fffffff, 0x7fffffff, 0x7fffffff};
  59 EXPORT_SYMBOL_GPL(coresight_barrier_pkt);
  60
  61 static const struct cti_assoc_op *cti_assoc_ops;
  62
  63 ssize_t coresight_simple_show_pair(struct device *_dev,
  64                               struct device_attribute *attr, char *buf)
  65 {
  66         struct coresight_device *csdev = container_of(_dev, struct coresight_device, dev);
  67         struct cs_pair_attribute *cs_attr = container_of(attr, struct cs_pair_attribute, attr);
  68         u64 val;
  69
  70         pm_runtime_get_sync(_dev->parent);
  71         val = csdev_access_relaxed_read_pair(&csdev->access, cs_attr->lo_off, cs_attr->hi_off);
  72         pm_runtime_put_sync(_dev->parent);
  73         return sysfs_emit(buf, "0x%llx\n", val);
  74 }
  75 EXPORT_SYMBOL_GPL(coresight_simple_show_pair);
  76
  77 ssize_t coresight_simple_show32(struct device *_dev,
  78                               struct device_attribute *attr, char *buf)
  79 {
  80         struct coresight_device *csdev = container_of(_dev, struct coresight_device, dev);
  81         struct cs_off_attribute *cs_attr = container_of(attr, struct cs_off_attribute, attr);
  82         u64 val;
  83
  84         pm_runtime_get_sync(_dev->parent);
  85         val = csdev_access_relaxed_read32(&csdev->access, cs_attr->off);
  86         pm_runtime_put_sync(_dev->parent);
  87         return sysfs_emit(buf, "0x%llx\n", val);
  88 }
  89 EXPORT_SYMBOL_GPL(coresight_simple_show32);
  90
  91 void coresight_set_cti_ops(const struct cti_assoc_op *cti_op)
  92 {
  93         cti_assoc_ops = cti_op;
  94 }
  95 EXPORT_SYMBOL_GPL(coresight_set_cti_ops);
  96
  97 void coresight_remove_cti_ops(void)
  98 {
  99         cti_assoc_ops = NULL;
 100 }
 101 EXPORT_SYMBOL_GPL(coresight_remove_cti_ops);
 102
 103 void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev)
 104 {
 105         per_cpu(csdev_sink, cpu) = csdev;
 106 }
 107 EXPORT_SYMBOL_GPL(coresight_set_percpu_sink);
 108
 109 struct coresight_device *coresight_get_percpu_sink(int cpu)
 110 {
 111         return per_cpu(csdev_sink, cpu);
 112 }
 113 EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
 114
 115 static int coresight_find_link_inport(struct coresight_device *csdev,
 116                                       struct coresight_device *parent)
 117 {
 118         int i;
 119         struct coresight_connection *conn;
 120
 121         for (i = 0; i < parent->pdata->nr_outport; i++) {
 122                 conn = &parent->pdata->conns[i];
 123                 if (conn->child_dev == csdev)
 124                         return conn->child_port;
 125         }
 126
 127         dev_err(&csdev->dev, "couldn't find inport, parent: %s, child: %s\n",
 128                 dev_name(&parent->dev), dev_name(&csdev->dev));
 129
 130         return -ENODEV;
 131 }
 132
 133 static int coresight_find_link_outport(struct coresight_device *csdev,
 134                                        struct coresight_device *child)
 135 {
 136         int i;
 137         struct coresight_connection *conn;
 138
 139         for (i = 0; i < csdev->pdata->nr_outport; i++) {
 140                 conn = &csdev->pdata->conns[i];
 141                 if (conn->child_dev == child)
 142                         return conn->outport;
 143         }
 144
 145         dev_err(&csdev->dev, "couldn't find outport, parent: %s, child: %s\n",
 146                 dev_name(&csdev->dev), dev_name(&child->dev));
 147
 148         return -ENODEV;
 149 }
 150
 151 static inline u32 coresight_read_claim_tags(struct coresight_device *csdev)
 152 {
 153         return csdev_access_relaxed_read32(&csdev->access, CORESIGHT_CLAIMCLR);
 154 }
 155
 156 static inline bool coresight_is_claimed_self_hosted(struct coresight_device *csdev)
 157 {
 158         return coresight_read_claim_tags(csdev) == CORESIGHT_CLAIM_SELF_HOSTED;
 159 }
 160
 161 static inline bool coresight_is_claimed_any(struct coresight_device *csdev)
 162 {
 163         return coresight_read_claim_tags(csdev) != 0;
 164 }
 165
 166 static inline void coresight_set_claim_tags(struct coresight_device *csdev)
 167 {
 168         csdev_access_relaxed_write32(&csdev->access, CORESIGHT_CLAIM_SELF_HOSTED,
 169                                      CORESIGHT_CLAIMSET);
 170         isb();
 171 }
 172
 173 static inline void coresight_clear_claim_tags(struct coresight_device *csdev)
 174 {
 175         csdev_access_relaxed_write32(&csdev->access, CORESIGHT_CLAIM_SELF_HOSTED,
 176                                      CORESIGHT_CLAIMCLR);
 177         isb();
 178 }
 179
 180 /*
 181  * coresight_claim_device_unlocked : Claim the device for self-hosted usage
 182  * to prevent an external tool from touching this device. As per PSCI
 183  * standards, section "Preserving the execution context" => "Debug and Trace
 184  * save and Restore", DBGCLAIM[1] is reserved for Self-hosted debug/trace and
 185  * DBGCLAIM[0] is reserved for external tools.
 186  *
 187  * Called with CS_UNLOCKed for the component.
 188  * Returns : 0 on success
 189  */
 190 int coresight_claim_device_unlocked(struct coresight_device *csdev)
 191 {
 192         if (WARN_ON(!csdev))
 193                 return -EINVAL;
 194
 195         if (coresight_is_claimed_any(csdev))
 196                 return -EBUSY;
 197
 198         coresight_set_claim_tags(csdev);
 199         if (coresight_is_claimed_self_hosted(csdev))
 200                 return 0;
 201         /* There was a race setting the tags, clean up and fail */
 202         coresight_clear_claim_tags(csdev);
 203         return -EBUSY;
 204 }
 205 EXPORT_SYMBOL_GPL(coresight_claim_device_unlocked);
 206
 207 int coresight_claim_device(struct coresight_device *csdev)
 208 {
 209         int rc;
 210
 211         if (WARN_ON(!csdev))
 212                 return -EINVAL;
 213
 214         CS_UNLOCK(csdev->access.base);
 215         rc = coresight_claim_device_unlocked(csdev);
 216         CS_LOCK(csdev->access.base);
 217
 218         return rc;
 219 }
 220 EXPORT_SYMBOL_GPL(coresight_claim_device);
 221
 222 /*
 223  * coresight_disclaim_device_unlocked : Clear the claim tags for the device.
 224  * Called with CS_UNLOCKed for the component.
 225  */
 226 void coresight_disclaim_device_unlocked(struct coresight_device *csdev)
 227 {
 228
 229         if (WARN_ON(!csdev))
 230                 return;
 231
 232         if (coresight_is_claimed_self_hosted(csdev))
 233                 coresight_clear_claim_tags(csdev);
 234         else
 235                 /*
 236                  * The external agent may have not honoured our claim
 237                  * and has manipulated it. Or something else has seriously
 238                  * gone wrong in our driver.
 239                  */
 240                 WARN_ON_ONCE(1);
 241 }
 242 EXPORT_SYMBOL_GPL(coresight_disclaim_device_unlocked);
 243
 244 void coresight_disclaim_device(struct coresight_device *csdev)
 245 {
 246         if (WARN_ON(!csdev))
 247                 return;
 248
 249         CS_UNLOCK(csdev->access.base);
 250         coresight_disclaim_device_unlocked(csdev);
 251         CS_LOCK(csdev->access.base);
 252 }
 253 EXPORT_SYMBOL_GPL(coresight_disclaim_device);
 254
 255 /* enable or disable an associated CTI device of the supplied CS device */
 256 static int
 257 coresight_control_assoc_ectdev(struct coresight_device *csdev, bool enable)
 258 {
 259         int ect_ret = 0;
 260         struct coresight_device *ect_csdev = csdev->ect_dev;
 261         struct module *mod;
 262
 263         if (!ect_csdev)
 264                 return 0;
 265         if ((!ect_ops(ect_csdev)->enable) || (!ect_ops(ect_csdev)->disable))
 266                 return 0;
 267
 268         mod = ect_csdev->dev.parent->driver->owner;
 269         if (enable) {
 270                 if (try_module_get(mod)) {
 271                         ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
 272                         if (ect_ret) {
 273                                 module_put(mod);
 274                         } else {
 275                                 get_device(ect_csdev->dev.parent);
 276                                 csdev->ect_enabled = true;
 277                         }
 278                 } else
 279                         ect_ret = -ENODEV;
 280         } else {
 281                 if (csdev->ect_enabled) {
 282                         ect_ret = ect_ops(ect_csdev)->disable(ect_csdev);
 283                         put_device(ect_csdev->dev.parent);
 284                         module_put(mod);
 285                         csdev->ect_enabled = false;
 286                 }
 287         }
 288
 289         /* output warning if ECT enable is preventing trace operation */
 290         if (ect_ret)
 291                 dev_info(&csdev->dev, "Associated ECT device (%s) %s failed\n",
 292                          dev_name(&ect_csdev->dev),
 293                          enable ? "enable" : "disable");
 294         return ect_ret;
 295 }
 296
 297 /*
 298  * Set the associated ect / cti device while holding the coresight_mutex
 299  * to avoid a race with coresight_enable that may try to use this value.
 300  */
 301 void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
 302                                       struct coresight_device *ect_csdev)
 303 {
 304         mutex_lock(&coresight_mutex);
 305         csdev->ect_dev = ect_csdev;
 306         mutex_unlock(&coresight_mutex);
 307 }
 308 EXPORT_SYMBOL_GPL(coresight_set_assoc_ectdev_mutex);
 309
 310 static int coresight_enable_sink(struct coresight_device *csdev,
 311                                  u32 mode, void *data)
 312 {
 313         int ret;
 314
 315         /*
 316          * We need to make sure the "new" session is compatible with the
 317          * existing "mode" of operation.
 318          */
 319         if (!sink_ops(csdev)->enable)
 320                 return -EINVAL;
 321
 322         ret = coresight_control_assoc_ectdev(csdev, true);
 323         if (ret)
 324                 return ret;
 325         ret = sink_ops(csdev)->enable(csdev, mode, data);
 326         if (ret) {
 327                 coresight_control_assoc_ectdev(csdev, false);
 328                 return ret;
 329         }
 330         csdev->enable = true;
 331
 332         return 0;
 333 }
 334
 335 static void coresight_disable_sink(struct coresight_device *csdev)
 336 {
 337         int ret;
 338
 339         if (!sink_ops(csdev)->disable)
 340                 return;
 341
 342         ret = sink_ops(csdev)->disable(csdev);
 343         if (ret)
 344                 return;
 345         coresight_control_assoc_ectdev(csdev, false);
 346         csdev->enable = false;
 347 }
 348
 349 static int coresight_enable_link(struct coresight_device *csdev,
 350                                  struct coresight_device *parent,
 351                                  struct coresight_device *child)
 352 {
 353         int ret = 0;
 354         int link_subtype;
 355         int inport, outport;
 356
 357         if (!parent || !child)
 358                 return -EINVAL;
 359
 360         inport = coresight_find_link_inport(csdev, parent);
 361         outport = coresight_find_link_outport(csdev, child);
 362         link_subtype = csdev->subtype.link_subtype;
 363
 364         if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG && inport < 0)
 365                 return inport;
 366         if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT && outport < 0)
 367                 return outport;
 368
 369         if (link_ops(csdev)->enable) {
 370                 ret = coresight_control_assoc_ectdev(csdev, true);
 371                 if (!ret) {
 372                         ret = link_ops(csdev)->enable(csdev, inport, outport);
 373                         if (ret)
 374                                 coresight_control_assoc_ectdev(csdev, false);
 375                 }
 376         }
 377
 378         if (!ret)
 379                 csdev->enable = true;
 380
 381         return ret;
 382 }
 383
 384 static void coresight_disable_link(struct coresight_device *csdev,
 385                                    struct coresight_device *parent,
 386                                    struct coresight_device *child)
 387 {
 388         int i, nr_conns;
 389         int link_subtype;
 390         int inport, outport;
 391
 392         if (!parent || !child)
 393                 return;
 394
 395         inport = coresight_find_link_inport(csdev, parent);
 396         outport = coresight_find_link_outport(csdev, child);
 397         link_subtype = csdev->subtype.link_subtype;
 398
 399         if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
 400                 nr_conns = csdev->pdata->nr_inport;
 401         } else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
 402                 nr_conns = csdev->pdata->nr_outport;
 403         } else {
 404                 nr_conns = 1;
 405         }
 406
 407         if (link_ops(csdev)->disable) {
 408                 link_ops(csdev)->disable(csdev, inport, outport);
 409                 coresight_control_assoc_ectdev(csdev, false);
 410         }
 411
 412         for (i = 0; i < nr_conns; i++)
 413                 if (atomic_read(&csdev->refcnt[i]) != 0)
 414                         return;
 415
 416         csdev->enable = false;
 417 }
 418
 419 static int coresight_enable_source(struct coresight_device *csdev, u32 mode)
 420 {
 421         int ret;
 422
 423         if (!csdev->enable) {
 424                 if (source_ops(csdev)->enable) {
 425                         ret = coresight_control_assoc_ectdev(csdev, true);
 426                         if (ret)
 427                                 return ret;
 428                         ret = source_ops(csdev)->enable(csdev, NULL, mode);
 429                         if (ret) {
 430                                 coresight_control_assoc_ectdev(csdev, false);
 431                                 return ret;
 432                         }
 433                 }
 434                 csdev->enable = true;
 435         }
 436
 437         atomic_inc(csdev->refcnt);
 438
 439         return 0;
 440 }
 441
 442 /**
 443  *  coresight_disable_source - Drop the reference count by 1 and disable
 444  *  the device if there are no users left.
 445  *
 446  *  @csdev: The coresight device to disable
 447  *
 448  *  Returns true if the device has been disabled.
 449  */
 450 static bool coresight_disable_source(struct coresight_device *csdev)
 451 {
 452         if (atomic_dec_return(csdev->refcnt) == 0) {
 453                 if (source_ops(csdev)->disable)
 454                         source_ops(csdev)->disable(csdev, NULL);
 455                 coresight_control_assoc_ectdev(csdev, false);
 456                 csdev->enable = false;
 457         }
 458         return !csdev->enable;
 459 }
 460
 461 /*
 462  * coresight_disable_path_from : Disable components in the given path beyond
 463  * @nd in the list. If @nd is NULL, all the components, except the SOURCE are
 464  * disabled.
 465  */
 466 static void coresight_disable_path_from(struct list_head *path,
 467                                         struct coresight_node *nd)
 468 {
 469         u32 type;
 470         struct coresight_device *csdev, *parent, *child;
 471
 472         if (!nd)
 473                 nd = list_first_entry(path, struct coresight_node, link);
 474
 475         list_for_each_entry_continue(nd, path, link) {
 476                 csdev = nd->csdev;
 477                 type = csdev->type;
 478
 479                 /*
 480                  * ETF devices are tricky... They can be a link or a sink,
 481                  * depending on how they are configured.  If an ETF has been
 482                  * "activated" it will be configured as a sink, otherwise
 483                  * go ahead with the link configuration.
 484                  */
 485                 if (type == CORESIGHT_DEV_TYPE_LINKSINK)
 486                         type = (csdev == coresight_get_sink(path)) ?
 487                                                 CORESIGHT_DEV_TYPE_SINK :
 488                                                 CORESIGHT_DEV_TYPE_LINK;
 489
 490                 switch (type) {
 491                 case CORESIGHT_DEV_TYPE_SINK:
 492                         coresight_disable_sink(csdev);
 493                         break;
 494                 case CORESIGHT_DEV_TYPE_SOURCE:
 495                         /*
 496                          * We skip the first node in the path assuming that it
 497                          * is the source. So we don't expect a source device in
 498                          * the middle of a path.
 499                          */
 500                         WARN_ON(1);
 501                         break;
 502                 case CORESIGHT_DEV_TYPE_LINK:
 503                         parent = list_prev_entry(nd, link)->csdev;
 504                         child = list_next_entry(nd, link)->csdev;
 505                         coresight_disable_link(csdev, parent, child);
 506                         break;
 507                 default:
 508                         break;
 509                 }
 510         }
 511 }
 512
 513 void coresight_disable_path(struct list_head *path)
 514 {
 515         coresight_disable_path_from(path, NULL);
 516 }
 517 EXPORT_SYMBOL_GPL(coresight_disable_path);
 518
 519 int coresight_enable_path(struct list_head *path, u32 mode, void *sink_data)
 520 {
 521
 522         int ret = 0;
 523         u32 type;
 524         struct coresight_node *nd;
 525         struct coresight_device *csdev, *parent, *child;
 526
 527         list_for_each_entry_reverse(nd, path, link) {
 528                 csdev = nd->csdev;
 529                 type = csdev->type;
 530
 531                 /*
 532                  * ETF devices are tricky... They can be a link or a sink,
 533                  * depending on how they are configured.  If an ETF has been
 534                  * "activated" it will be configured as a sink, otherwise
 535                  * go ahead with the link configuration.
 536                  */
 537                 if (type == CORESIGHT_DEV_TYPE_LINKSINK)
 538                         type = (csdev == coresight_get_sink(path)) ?
 539                                                 CORESIGHT_DEV_TYPE_SINK :
 540                                                 CORESIGHT_DEV_TYPE_LINK;
 541
 542                 switch (type) {
 543                 case CORESIGHT_DEV_TYPE_SINK:
 544                         ret = coresight_enable_sink(csdev, mode, sink_data);
 545                         /*
 546                          * Sink is the first component turned on. If we
 547                          * failed to enable the sink, there are no components
 548                          * that need disabling. Disabling the path here
 549                          * would mean we could disrupt an existing session.
 550                          */
 551                         if (ret)
 552                                 goto out;
 553                         break;
 554                 case CORESIGHT_DEV_TYPE_SOURCE:
 555                         /* sources are enabled from either sysFS or Perf */
 556                         break;
 557                 case CORESIGHT_DEV_TYPE_LINK:
 558                         parent = list_prev_entry(nd, link)->csdev;
 559                         child = list_next_entry(nd, link)->csdev;
 560                         ret = coresight_enable_link(csdev, parent, child);
 561                         if (ret)
 562                                 goto err;
 563                         break;
 564                 default:
 565                         goto err;
 566                 }
 567         }
 568
 569 out:
 570         return ret;
 571 err:
 572         coresight_disable_path_from(path, nd);
 573         goto out;
 574 }
 575
 576 struct coresight_device *coresight_get_sink(struct list_head *path)
 577 {
 578         struct coresight_device *csdev;
 579
 580         if (!path)
 581                 return NULL;
 582
 583         csdev = list_last_entry(path, struct coresight_node, link)->csdev;
 584         if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
 585             csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
 586                 return NULL;
 587
 588         return csdev;
 589 }
 590
 591 static struct coresight_device *
 592 coresight_find_enabled_sink(struct coresight_device *csdev)
 593 {
 594         int i;
 595         struct coresight_device *sink = NULL;
 596
 597         if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
 598              csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
 599              csdev->activated)
 600                 return csdev;
 601
 602         /*
 603          * Recursively explore each port found on this element.
 604          */
 605         for (i = 0; i < csdev->pdata->nr_outport; i++) {
 606                 struct coresight_device *child_dev;
 607
 608                 child_dev = csdev->pdata->conns[i].child_dev;
 609                 if (child_dev)
 610                         sink = coresight_find_enabled_sink(child_dev);
 611                 if (sink)
 612                         return sink;
 613         }
 614
 615         return NULL;
 616 }
 617
 618 /**
 619  * coresight_get_enabled_sink - returns the first enabled sink using
 620  * connection based search starting from the source reference
 621  *
 622  * @source: Coresight source device reference
 623  */
 624 struct coresight_device *
 625 coresight_get_enabled_sink(struct coresight_device *source)
 626 {
 627         if (!source)
 628                 return NULL;
 629
 630         return coresight_find_enabled_sink(source);
 631 }
 632
 633 static int coresight_sink_by_id(struct device *dev, const void *data)
 634 {
 635         struct coresight_device *csdev = to_coresight_device(dev);
 636         unsigned long hash;
 637
 638         if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
 639              csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
 640
 641                 if (!csdev->ea)
 642                         return 0;
 643                 /*
 644                  * See function etm_perf_add_symlink_sink() to know where
 645                  * this comes from.
 646                  */
 647                 hash = (unsigned long)csdev->ea->var;
 648
 649                 if ((u32)hash == *(u32 *)data)
 650                         return 1;
 651         }
 652
 653         return 0;
 654 }
 655
 656 /**
 657  * coresight_get_sink_by_id - returns the sink that matches the id
 658  * @id: Id of the sink to match
 659  *
 660  * The name of a sink is unique, whether it is found on the AMBA bus or
 661  * otherwise.  As such the hash of that name can easily be used to identify
 662  * a sink.
 663  */
 664 struct coresight_device *coresight_get_sink_by_id(u32 id)
 665 {
 666         struct device *dev = NULL;
 667
 668         dev = bus_find_device(&coresight_bustype, NULL, &id,
 669                               coresight_sink_by_id);
 670
 671         return dev ? to_coresight_device(dev) : NULL;
 672 }
 673
 674 /**
 675  * coresight_get_ref- Helper function to increase reference count to module
 676  * and device.
 677  *
 678  * @csdev: The coresight device to get a reference on.
 679  *
 680  * Return true in successful case and power up the device.
 681  * Return false when failed to get reference of module.
 682  */
 683 static inline bool coresight_get_ref(struct coresight_device *csdev)
 684 {
 685         struct device *dev = csdev->dev.parent;
 686
 687         /* Make sure the driver can't be removed */
 688         if (!try_module_get(dev->driver->owner))
 689                 return false;
 690         /* Make sure the device can't go away */
 691         get_device(dev);
 692         pm_runtime_get_sync(dev);
 693         return true;
 694 }
 695
 696 /**
 697  * coresight_put_ref- Helper function to decrease reference count to module
 698  * and device. Power off the device.
 699  *
 700  * @csdev: The coresight device to decrement a reference from.
 701  */
 702 static inline void coresight_put_ref(struct coresight_device *csdev)
 703 {
 704         struct device *dev = csdev->dev.parent;
 705
 706         pm_runtime_put(dev);
 707         put_device(dev);
 708         module_put(dev->driver->owner);
 709 }
 710
 711 /*
 712  * coresight_grab_device - Power up this device and any of the helper
 713  * devices connected to it for trace operation. Since the helper devices
 714  * don't appear on the trace path, they should be handled along with the
 715  * master device.
 716  */
 717 static int coresight_grab_device(struct coresight_device *csdev)
 718 {
 719         int i;
 720
 721         for (i = 0; i < csdev->pdata->nr_outport; i++) {
 722                 struct coresight_device *child;
 723
 724                 child  = csdev->pdata->conns[i].child_dev;
 725                 if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
 726                         if (!coresight_get_ref(child))
 727                                 goto err;
 728         }
 729         if (coresight_get_ref(csdev))
 730                 return 0;
 731 err:
 732         for (i--; i >= 0; i--) {
 733                 struct coresight_device *child;
 734
 735                 child  = csdev->pdata->conns[i].child_dev;
 736                 if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
 737                         coresight_put_ref(child);
 738         }
 739         return -ENODEV;
 740 }
 741
 742 /*
 743  * coresight_drop_device - Release this device and any of the helper
 744  * devices connected to it.
 745  */
 746 static void coresight_drop_device(struct coresight_device *csdev)
 747 {
 748         int i;
 749
 750         coresight_put_ref(csdev);
 751         for (i = 0; i < csdev->pdata->nr_outport; i++) {
 752                 struct coresight_device *child;
 753
 754                 child  = csdev->pdata->conns[i].child_dev;
 755                 if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
 756                         coresight_put_ref(child);
 757         }
 758 }
 759
 760 /**
 761  * _coresight_build_path - recursively build a path from a @csdev to a sink.
 762  * @csdev:      The device to start from.
 763  * @sink:       The final sink we want in this path.
 764  * @path:       The list to add devices to.
 765  *
 766  * The tree of Coresight device is traversed until an activated sink is
 767  * found.  From there the sink is added to the list along with all the
 768  * devices that led to that point - the end result is a list from source
 769  * to sink. In that list the source is the first device and the sink the
 770  * last one.
 771  */
 772 static int _coresight_build_path(struct coresight_device *csdev,
 773                                  struct coresight_device *sink,
 774                                  struct list_head *path)
 775 {
 776         int i, ret;
 777         bool found = false;
 778         struct coresight_node *node;
 779
 780         /* An activated sink has been found.  Enqueue the element */
 781         if (csdev == sink)
 782                 goto out;
 783
 784         if (coresight_is_percpu_source(csdev) && coresight_is_percpu_sink(sink) &&
 785             sink == per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev))) {
 786                 if (_coresight_build_path(sink, sink, path) == 0) {
 787                         found = true;
 788                         goto out;
 789                 }
 790         }
 791
 792         /* Not a sink - recursively explore each port found on this element */
 793         for (i = 0; i < csdev->pdata->nr_outport; i++) {
 794                 struct coresight_device *child_dev;
 795
 796                 child_dev = csdev->pdata->conns[i].child_dev;
 797                 if (child_dev &&
 798                     _coresight_build_path(child_dev, sink, path) == 0) {
 799                         found = true;
 800                         break;
 801                 }
 802         }
 803
 804         if (!found)
 805                 return -ENODEV;
 806
 807 out:
 808         /*
 809          * A path from this element to a sink has been found.  The elements
 810          * leading to the sink are already enqueued, all that is left to do
 811          * is tell the PM runtime core we need this element and add a node
 812          * for it.
 813          */
 814         ret = coresight_grab_device(csdev);
 815         if (ret)
 816                 return ret;
 817
 818         node = kzalloc(sizeof(struct coresight_node), GFP_KERNEL);
 819         if (!node)
 820                 return -ENOMEM;
 821
 822         node->csdev = csdev;
 823         list_add(&node->link, path);
 824
 825         return 0;
 826 }
 827
 828 struct list_head *coresight_build_path(struct coresight_device *source,
 829                                        struct coresight_device *sink)
 830 {
 831         struct list_head *path;
 832         int rc;
 833
 834         if (!sink)
 835                 return ERR_PTR(-EINVAL);
 836
 837         path = kzalloc(sizeof(struct list_head), GFP_KERNEL);
 838         if (!path)
 839                 return ERR_PTR(-ENOMEM);
 840
 841         INIT_LIST_HEAD(path);
 842
 843         rc = _coresight_build_path(source, sink, path);
 844         if (rc) {
 845                 kfree(path);
 846                 return ERR_PTR(rc);
 847         }
 848
 849         return path;
 850 }
 851
 852 /**
 853  * coresight_release_path - release a previously built path.
 854  * @path:       the path to release.
 855  *
 856  * Go through all the elements of a path and 1) removed it from the list and
 857  * 2) free the memory allocated for each node.
 858  */
 859 void coresight_release_path(struct list_head *path)
 860 {
 861         struct coresight_device *csdev;
 862         struct coresight_node *nd, *next;
 863
 864         list_for_each_entry_safe(nd, next, path, link) {
 865                 csdev = nd->csdev;
 866
 867                 coresight_drop_device(csdev);
 868                 list_del(&nd->link);
 869                 kfree(nd);
 870         }
 871
 872         kfree(path);
 873 }
 874
 875 /* return true if the device is a suitable type for a default sink */
 876 static inline bool coresight_is_def_sink_type(struct coresight_device *csdev)
 877 {
 878         /* sink & correct subtype */
 879         if (((csdev->type == CORESIGHT_DEV_TYPE_SINK) ||
 880              (csdev->type == CORESIGHT_DEV_TYPE_LINKSINK)) &&
 881             (csdev->subtype.sink_subtype >= CORESIGHT_DEV_SUBTYPE_SINK_BUFFER))
 882                 return true;
 883         return false;
 884 }
 885
 886 /**
 887  * coresight_select_best_sink - return the best sink for use as default from
 888  * the two provided.
 889  *
 890  * @sink:       current best sink.
 891  * @depth:      search depth where current sink was found.
 892  * @new_sink:   new sink for comparison with current sink.
 893  * @new_depth:  search depth where new sink was found.
 894  *
 895  * Sinks prioritised according to coresight_dev_subtype_sink, with only
 896  * subtypes CORESIGHT_DEV_SUBTYPE_SINK_BUFFER or higher being used.
 897  *
 898  * Where two sinks of equal priority are found, the sink closest to the
 899  * source is used (smallest search depth).
 900  *
 901  * return @new_sink & update @depth if better than @sink, else return @sink.
 902  */
 903 static struct coresight_device *
 904 coresight_select_best_sink(struct coresight_device *sink, int *depth,
 905                            struct coresight_device *new_sink, int new_depth)
 906 {
 907         bool update = false;
 908
 909         if (!sink) {
 910                 /* first found at this level */
 911                 update = true;
 912         } else if (new_sink->subtype.sink_subtype >
 913                    sink->subtype.sink_subtype) {
 914                 /* found better sink */
 915                 update = true;
 916         } else if ((new_sink->subtype.sink_subtype ==
 917                     sink->subtype.sink_subtype) &&
 918                    (*depth > new_depth)) {
 919                 /* found same but closer sink */
 920                 update = true;
 921         }
 922
 923         if (update)
 924                 *depth = new_depth;
 925         return update ? new_sink : sink;
 926 }
 927
 928 /**
 929  * coresight_find_sink - recursive function to walk trace connections from
 930  * source to find a suitable default sink.
 931  *
 932  * @csdev: source / current device to check.
 933  * @depth: [in] search depth of calling dev, [out] depth of found sink.
 934  *
 935  * This will walk the connection path from a source (ETM) till a suitable
 936  * sink is encountered and return that sink to the original caller.
 937  *
 938  * If current device is a plain sink return that & depth, otherwise recursively
 939  * call child connections looking for a sink. Select best possible using
 940  * coresight_select_best_sink.
 941  *
 942  * return best sink found, or NULL if not found at this node or child nodes.
 943  */
 944 static struct coresight_device *
 945 coresight_find_sink(struct coresight_device *csdev, int *depth)
 946 {
 947         int i, curr_depth = *depth + 1, found_depth = 0;
 948         struct coresight_device *found_sink = NULL;
 949
 950         if (coresight_is_def_sink_type(csdev)) {
 951                 found_depth = curr_depth;
 952                 found_sink = csdev;
 953                 if (csdev->type == CORESIGHT_DEV_TYPE_SINK)
 954                         goto return_def_sink;
 955                 /* look past LINKSINK for something better */
 956         }
 957
 958         /*
 959          * Not a sink we want - or possible child sink may be better.
 960          * recursively explore each port found on this element.
 961          */
 962         for (i = 0; i < csdev->pdata->nr_outport; i++) {
 963                 struct coresight_device *child_dev, *sink = NULL;
 964                 int child_depth = curr_depth;
 965
 966                 child_dev = csdev->pdata->conns[i].child_dev;
 967                 if (child_dev)
 968                         sink = coresight_find_sink(child_dev, &child_depth);
 969
 970                 if (sink)
 971                         found_sink = coresight_select_best_sink(found_sink,
 972                                                                 &found_depth,
 973                                                                 sink,
 974                                                                 child_depth);
 975         }
 976
 977 return_def_sink:
 978         /* return found sink and depth */
 979         if (found_sink)
 980                 *depth = found_depth;
 981         return found_sink;
 982 }
 983
 984 /**
 985  * coresight_find_default_sink: Find a sink suitable for use as a
 986  * default sink.
 987  *
 988  * @csdev: starting source to find a connected sink.
 989  *
 990  * Walks connections graph looking for a suitable sink to enable for the
 991  * supplied source. Uses CoreSight device subtypes and distance from source
 992  * to select the best sink.
 993  *
 994  * If a sink is found, then the default sink for this device is set and
 995  * will be automatically used in future.
 996  *
 997  * Used in cases where the CoreSight user (perf / sysfs) has not selected a
 998  * sink.
 999  */
1000 struct coresight_device *
1001 coresight_find_default_sink(struct coresight_device *csdev)
1002 {
1003         int depth = 0;
1004
1005         /* look for a default sink if we have not found for this device */
1006         if (!csdev->def_sink) {
1007                 if (coresight_is_percpu_source(csdev))
1008                         csdev->def_sink = per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev));
1009                 if (!csdev->def_sink)
1010                         csdev->def_sink = coresight_find_sink(csdev, &depth);
1011         }
1012         return csdev->def_sink;
1013 }
1014
1015 static int coresight_remove_sink_ref(struct device *dev, void *data)
1016 {
1017         struct coresight_device *sink = data;
1018         struct coresight_device *source = to_coresight_device(dev);
1019
1020         if (source->def_sink == sink)
1021                 source->def_sink = NULL;
1022         return 0;
1023 }
1024
1025 /**
1026  * coresight_clear_default_sink: Remove all default sink references to the
1027  * supplied sink.
1028  *
1029  * If supplied device is a sink, then check all the bus devices and clear
1030  * out all the references to this sink from the coresight_device def_sink
1031  * parameter.
1032  *
1033  * @csdev: coresight sink - remove references to this from all sources.
1034  */
1035 static void coresight_clear_default_sink(struct coresight_device *csdev)
1036 {
1037         if ((csdev->type == CORESIGHT_DEV_TYPE_SINK) ||
1038             (csdev->type == CORESIGHT_DEV_TYPE_LINKSINK)) {
1039                 bus_for_each_dev(&coresight_bustype, NULL, csdev,
1040                                  coresight_remove_sink_ref);
1041         }
1042 }
1043
1044 /** coresight_validate_source - make sure a source has the right credentials
1045  *  @csdev:     the device structure for a source.
1046  *  @function:  the function this was called from.
1047  *
1048  * Assumes the coresight_mutex is held.
1049  */
1050 static int coresight_validate_source(struct coresight_device *csdev,
1051                                      const char *function)
1052 {
1053         u32 type, subtype;
1054
1055         type = csdev->type;
1056         subtype = csdev->subtype.source_subtype;
1057
1058         if (type != CORESIGHT_DEV_TYPE_SOURCE) {
1059                 dev_err(&csdev->dev, "wrong device type in %s\n", function);
1060                 return -EINVAL;
1061         }
1062
1063         if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC &&
1064             subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE &&
1065             subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS) {
1066                 dev_err(&csdev->dev, "wrong device subtype in %s\n", function);
1067                 return -EINVAL;
1068         }
1069
1070         return 0;
1071 }
1072
1073 int coresight_enable(struct coresight_device *csdev)
1074 {
1075         int cpu, ret = 0;
1076         struct coresight_device *sink;
1077         struct list_head *path;
1078         enum coresight_dev_subtype_source subtype;
1079         u32 hash;
1080
1081         subtype = csdev->subtype.source_subtype;
1082
1083         mutex_lock(&coresight_mutex);
1084
1085         ret = coresight_validate_source(csdev, __func__);
1086         if (ret)
1087                 goto out;
1088
1089         if (csdev->enable) {
1090                 /*
1091                  * There could be multiple applications driving the software
1092                  * source. So keep the refcount for each such user when the
1093                  * source is already enabled.
1094                  */
1095                 if (subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE)
1096                         atomic_inc(csdev->refcnt);
1097                 goto out;
1098         }
1099
1100         sink = coresight_get_enabled_sink(csdev);
1101         if (!sink) {
1102                 ret = -EINVAL;
1103                 goto out;
1104         }
1105
1106         path = coresight_build_path(csdev, sink);
1107         if (IS_ERR(path)) {
1108                 pr_err("building path(s) failed\n");
1109                 ret = PTR_ERR(path);
1110                 goto out;
1111         }
1112
1113         ret = coresight_enable_path(path, CS_MODE_SYSFS, NULL);
1114         if (ret)
1115                 goto err_path;
1116
1117         ret = coresight_enable_source(csdev, CS_MODE_SYSFS);
1118         if (ret)
1119                 goto err_source;
1120
1121         switch (subtype) {
1122         case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
1123                 /*
1124                  * When working from sysFS it is important to keep track
1125                  * of the paths that were created so that they can be
1126                  * undone in 'coresight_disable()'.  Since there can only
1127                  * be a single session per tracer (when working from sysFS)
1128                  * a per-cpu variable will do just fine.
1129                  */
1130                 cpu = source_ops(csdev)->cpu_id(csdev);
1131                 per_cpu(tracer_path, cpu) = path;
1132                 break;
1133         case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
1134         case CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS:
1135                 /*
1136                  * Use the hash of source's device name as ID
1137                  * and map the ID to the pointer of the path.
1138                  */
1139                 hash = hashlen_hash(hashlen_string(NULL, dev_name(&csdev->dev)));
1140                 ret = idr_alloc_u32(&path_idr, path, &hash, hash, GFP_KERNEL);
1141                 if (ret)
1142                         goto err_source;
1143                 break;
1144         default:
1145                 /* We can't be here */
1146                 break;
1147         }
1148
1149 out:
1150         mutex_unlock(&coresight_mutex);
1151         return ret;
1152
1153 err_source:
1154         coresight_disable_path(path);
1155
1156 err_path:
1157         coresight_release_path(path);
1158         goto out;
1159 }
1160 EXPORT_SYMBOL_GPL(coresight_enable);
1161
1162 void coresight_disable(struct coresight_device *csdev)
1163 {
1164         int cpu, ret;
1165         struct list_head *path = NULL;
1166         u32 hash;
1167
1168         mutex_lock(&coresight_mutex);
1169
1170         ret = coresight_validate_source(csdev, __func__);
1171         if (ret)
1172                 goto out;
1173
1174         if (!csdev->enable || !coresight_disable_source(csdev))
1175                 goto out;
1176
1177         switch (csdev->subtype.source_subtype) {
1178         case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
1179                 cpu = source_ops(csdev)->cpu_id(csdev);
1180                 path = per_cpu(tracer_path, cpu);
1181                 per_cpu(tracer_path, cpu) = NULL;
1182                 break;
1183         case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
1184         case CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS:
1185                 hash = hashlen_hash(hashlen_string(NULL, dev_name(&csdev->dev)));
1186                 /* Find the path by the hash. */
1187                 path = idr_find(&path_idr, hash);
1188                 if (path == NULL) {
1189                         pr_err("Path is not found for %s\n", dev_name(&csdev->dev));
1190                         goto out;
1191                 }
1192                 idr_remove(&path_idr, hash);
1193                 break;
1194         default:
1195                 /* We can't be here */
1196                 break;
1197         }
1198
1199         coresight_disable_path(path);
1200         coresight_release_path(path);
1201
1202 out:
1203         mutex_unlock(&coresight_mutex);
1204 }
1205 EXPORT_SYMBOL_GPL(coresight_disable);
1206
1207 static ssize_t enable_sink_show(struct device *dev,
1208                                 struct device_attribute *attr, char *buf)
1209 {
1210         struct coresight_device *csdev = to_coresight_device(dev);
1211
1212         return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->activated);
1213 }
1214
1215 static ssize_t enable_sink_store(struct device *dev,
1216                                  struct device_attribute *attr,
1217                                  const char *buf, size_t size)
1218 {
1219         int ret;
1220         unsigned long val;
1221         struct coresight_device *csdev = to_coresight_device(dev);
1222
1223         ret = kstrtoul(buf, 10, &val);
1224         if (ret)
1225                 return ret;
1226
1227         if (val)
1228                 csdev->activated = true;
1229         else
1230                 csdev->activated = false;
1231
1232         return size;
1233
1234 }
1235 static DEVICE_ATTR_RW(enable_sink);
1236
1237 static ssize_t enable_source_show(struct device *dev,
1238                                   struct device_attribute *attr, char *buf)
1239 {
1240         struct coresight_device *csdev = to_coresight_device(dev);
1241
1242         return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->enable);
1243 }
1244
1245 static ssize_t enable_source_store(struct device *dev,
1246                                    struct device_attribute *attr,
1247                                    const char *buf, size_t size)
1248 {
1249         int ret = 0;
1250         unsigned long val;
1251         struct coresight_device *csdev = to_coresight_device(dev);
1252
1253         ret = kstrtoul(buf, 10, &val);
1254         if (ret)
1255                 return ret;
1256
1257         if (val) {
1258                 ret = coresight_enable(csdev);
1259                 if (ret)
1260                         return ret;
1261         } else {
1262                 coresight_disable(csdev);
1263         }
1264
1265         return size;
1266 }
1267 static DEVICE_ATTR_RW(enable_source);
1268
1269 static struct attribute *coresight_sink_attrs[] = {
1270         &dev_attr_enable_sink.attr,
1271         NULL,
1272 };
1273 ATTRIBUTE_GROUPS(coresight_sink);
1274
1275 static struct attribute *coresight_source_attrs[] = {
1276         &dev_attr_enable_source.attr,
1277         NULL,
1278 };
1279 ATTRIBUTE_GROUPS(coresight_source);
1280
1281 static struct device_type coresight_dev_type[] = {
1282         {
1283                 .name = "sink",
1284                 .groups = coresight_sink_groups,
1285         },
1286         {
1287                 .name = "link",
1288         },
1289         {
1290                 .name = "linksink",
1291                 .groups = coresight_sink_groups,
1292         },
1293         {
1294                 .name = "source",
1295                 .groups = coresight_source_groups,
1296         },
1297         {
1298                 .name = "helper",
1299         },
1300         {
1301                 .name = "ect",
1302         },
1303 };
1304
1305 static void coresight_device_release(struct device *dev)
1306 {
1307         struct coresight_device *csdev = to_coresight_device(dev);
1308
1309         fwnode_handle_put(csdev->dev.fwnode);
1310         kfree(csdev->refcnt);
1311         kfree(csdev);
1312 }
1313
1314 static int coresight_orphan_match(struct device *dev, void *data)
1315 {
1316         int i, ret = 0;
1317         bool still_orphan = false;
1318         struct coresight_device *csdev, *i_csdev;
1319         struct coresight_connection *conn;
1320
1321         csdev = data;
1322         i_csdev = to_coresight_device(dev);
1323
1324         /* No need to check oneself */
1325         if (csdev == i_csdev)
1326                 return 0;
1327
1328         /* Move on to another component if no connection is orphan */
1329         if (!i_csdev->orphan)
1330                 return 0;
1331         /*
1332          * Circle throuch all the connection of that component.  If we find
1333          * an orphan connection whose name matches @csdev, link it.
1334          */
1335         for (i = 0; i < i_csdev->pdata->nr_outport; i++) {
1336                 conn = &i_csdev->pdata->conns[i];
1337
1338                 /* Skip the port if FW doesn't describe it */
1339                 if (!conn->child_fwnode)
1340                         continue;
1341                 /* We have found at least one orphan connection */
1342                 if (conn->child_dev == NULL) {
1343                         /* Does it match this newly added device? */
1344                         if (conn->child_fwnode == csdev->dev.fwnode) {
1345                                 ret = coresight_make_links(i_csdev,
1346                                                            conn, csdev);
1347                                 if (ret)
1348                                         return ret;
1349                         } else {
1350                                 /* This component still has an orphan */
1351                                 still_orphan = true;
1352                         }
1353                 }
1354         }
1355
1356         i_csdev->orphan = still_orphan;
1357
1358         /*
1359          * Returning '0' in case we didn't encounter any error,
1360          * ensures that all known component on the bus will be checked.
1361          */
1362         return 0;
1363 }
1364
1365 static int coresight_fixup_orphan_conns(struct coresight_device *csdev)
1366 {
1367         return bus_for_each_dev(&coresight_bustype, NULL,
1368                          csdev, coresight_orphan_match);
1369 }
1370
1371
1372 static int coresight_fixup_device_conns(struct coresight_device *csdev)
1373 {
1374         int i, ret = 0;
1375
1376         for (i = 0; i < csdev->pdata->nr_outport; i++) {
1377                 struct coresight_connection *conn = &csdev->pdata->conns[i];
1378
1379                 if (!conn->child_fwnode)
1380                         continue;
1381                 conn->child_dev =
1382                         coresight_find_csdev_by_fwnode(conn->child_fwnode);
1383                 if (conn->child_dev && conn->child_dev->has_conns_grp) {
1384                         ret = coresight_make_links(csdev, conn,
1385                                                    conn->child_dev);
1386                         if (ret)
1387                                 break;
1388                 } else {
1389                         csdev->orphan = true;
1390                 }
1391         }
1392
1393         return ret;
1394 }
1395
1396 static int coresight_remove_match(struct device *dev, void *data)
1397 {
1398         int i;
1399         struct coresight_device *csdev, *iterator;
1400         struct coresight_connection *conn;
1401
1402         csdev = data;
1403         iterator = to_coresight_device(dev);
1404
1405         /* No need to check oneself */
1406         if (csdev == iterator)
1407                 return 0;
1408
1409         /*
1410          * Circle throuch all the connection of that component.  If we find
1411          * a connection whose name matches @csdev, remove it.
1412          */
1413         for (i = 0; i < iterator->pdata->nr_outport; i++) {
1414                 conn = &iterator->pdata->conns[i];
1415
1416                 if (conn->child_dev == NULL || conn->child_fwnode == NULL)
1417                         continue;
1418
1419                 if (csdev->dev.fwnode == conn->child_fwnode) {
1420                         iterator->orphan = true;
1421                         coresight_remove_links(iterator, conn);
1422                         /*
1423                          * Drop the reference to the handle for the remote
1424                          * device acquired in parsing the connections from
1425                          * platform data.
1426                          */
1427                         fwnode_handle_put(conn->child_fwnode);
1428                         conn->child_fwnode = NULL;
1429                         /* No need to continue */
1430                         break;
1431                 }
1432         }
1433
1434         /*
1435          * Returning '0' ensures that all known component on the
1436          * bus will be checked.
1437          */
1438         return 0;
1439 }
1440
1441 /*
1442  * coresight_remove_conns - Remove references to this given devices
1443  * from the connections of other devices.
1444  */
1445 static void coresight_remove_conns(struct coresight_device *csdev)
1446 {
1447         /*
1448          * Another device will point to this device only if there is
1449          * an output port connected to this one. i.e, if the device
1450          * doesn't have at least one input port, there is no point
1451          * in searching all the devices.
1452          */
1453         if (csdev->pdata->nr_inport)
1454                 bus_for_each_dev(&coresight_bustype, NULL,
1455                                  csdev, coresight_remove_match);
1456 }
1457
1458 /**
1459  * coresight_timeout - loop until a bit has changed to a specific register
1460  *                      state.
1461  * @csa: coresight device access for the device
1462  * @offset: Offset of the register from the base of the device.
1463  * @position: the position of the bit of interest.
1464  * @value: the value the bit should have.
1465  *
1466  * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
1467  * TIMEOUT_US has elapsed, which ever happens first.
1468  */
1469 int coresight_timeout(struct csdev_access *csa, u32 offset,
1470                       int position, int value)
1471 {
1472         int i;
1473         u32 val;
1474
1475         for (i = TIMEOUT_US; i > 0; i--) {
1476                 val = csdev_access_read32(csa, offset);
1477                 /* waiting on the bit to go from 0 to 1 */
1478                 if (value) {
1479                         if (val & BIT(position))
1480                                 return 0;
1481                 /* waiting on the bit to go from 1 to 0 */
1482                 } else {
1483                         if (!(val & BIT(position)))
1484                                 return 0;
1485                 }
1486
1487                 /*
1488                  * Delay is arbitrary - the specification doesn't say how long
1489                  * we are expected to wait.  Extra check required to make sure
1490                  * we don't wait needlessly on the last iteration.
1491                  */
1492                 if (i - 1)
1493                         udelay(1);
1494         }
1495
1496         return -EAGAIN;
1497 }
1498 EXPORT_SYMBOL_GPL(coresight_timeout);
1499
1500 u32 coresight_relaxed_read32(struct coresight_device *csdev, u32 offset)
1501 {
1502         return csdev_access_relaxed_read32(&csdev->access, offset);
1503 }
1504
1505 u32 coresight_read32(struct coresight_device *csdev, u32 offset)
1506 {
1507         return csdev_access_read32(&csdev->access, offset);
1508 }
1509
1510 void coresight_relaxed_write32(struct coresight_device *csdev,
1511                                u32 val, u32 offset)
1512 {
1513         csdev_access_relaxed_write32(&csdev->access, val, offset);
1514 }
1515
1516 void coresight_write32(struct coresight_device *csdev, u32 val, u32 offset)
1517 {
1518         csdev_access_write32(&csdev->access, val, offset);
1519 }
1520
1521 u64 coresight_relaxed_read64(struct coresight_device *csdev, u32 offset)
1522 {
1523         return csdev_access_relaxed_read64(&csdev->access, offset);
1524 }
1525
1526 u64 coresight_read64(struct coresight_device *csdev, u32 offset)
1527 {
1528         return csdev_access_read64(&csdev->access, offset);
1529 }
1530
1531 void coresight_relaxed_write64(struct coresight_device *csdev,
1532                                u64 val, u32 offset)
1533 {
1534         csdev_access_relaxed_write64(&csdev->access, val, offset);
1535 }
1536
1537 void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset)
1538 {
1539         csdev_access_write64(&csdev->access, val, offset);
1540 }
1541
1542 /*
1543  * coresight_release_platform_data: Release references to the devices connected
1544  * to the output port of this device.
1545  */
1546 void coresight_release_platform_data(struct coresight_device *csdev,
1547                                      struct coresight_platform_data *pdata)
1548 {
1549         int i;
1550         struct coresight_connection *conns = pdata->conns;
1551
1552         for (i = 0; i < pdata->nr_outport; i++) {
1553                 /* If we have made the links, remove them now */
1554                 if (csdev && conns[i].child_dev)
1555                         coresight_remove_links(csdev, &conns[i]);
1556                 /*
1557                  * Drop the refcount and clear the handle as this device
1558                  * is going away
1559                  */
1560                 if (conns[i].child_fwnode) {
1561                         fwnode_handle_put(conns[i].child_fwnode);
1562                         pdata->conns[i].child_fwnode = NULL;
1563                 }
1564         }
1565         if (csdev)
1566                 coresight_remove_conns_sysfs_group(csdev);
1567 }
1568
1569 struct coresight_device *coresight_register(struct coresight_desc *desc)
1570 {
1571         int ret;
1572         int link_subtype;
1573         int nr_refcnts = 1;
1574         atomic_t *refcnts = NULL;
1575         struct coresight_device *csdev;
1576         bool registered = false;
1577
1578         csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
1579         if (!csdev) {
1580                 ret = -ENOMEM;
1581                 goto err_out;
1582         }
1583
1584         if (desc->type == CORESIGHT_DEV_TYPE_LINK ||
1585             desc->type == CORESIGHT_DEV_TYPE_LINKSINK) {
1586                 link_subtype = desc->subtype.link_subtype;
1587
1588                 if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
1589                         nr_refcnts = desc->pdata->nr_inport;
1590                 else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
1591                         nr_refcnts = desc->pdata->nr_outport;
1592         }
1593
1594         refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
1595         if (!refcnts) {
1596                 ret = -ENOMEM;
1597                 kfree(csdev);
1598                 goto err_out;
1599         }
1600
1601         csdev->refcnt = refcnts;
1602
1603         csdev->pdata = desc->pdata;
1604
1605         csdev->type = desc->type;
1606         csdev->subtype = desc->subtype;
1607         csdev->ops = desc->ops;
1608         csdev->access = desc->access;
1609         csdev->orphan = false;
1610
1611         csdev->dev.type = &coresight_dev_type[desc->type];
1612         csdev->dev.groups = desc->groups;
1613         csdev->dev.parent = desc->dev;
1614         csdev->dev.release = coresight_device_release;
1615         csdev->dev.bus = &coresight_bustype;
1616         /*
1617          * Hold the reference to our parent device. This will be
1618          * dropped only in coresight_device_release().
1619          */
1620         csdev->dev.fwnode = fwnode_handle_get(dev_fwnode(desc->dev));
1621         dev_set_name(&csdev->dev, "%s", desc->name);
1622
1623         /*
1624          * Make sure the device registration and the connection fixup
1625          * are synchronised, so that we don't see uninitialised devices
1626          * on the coresight bus while trying to resolve the connections.
1627          */
1628         mutex_lock(&coresight_mutex);
1629
1630         ret = device_register(&csdev->dev);
1631         if (ret) {
1632                 put_device(&csdev->dev);
1633                 /*
1634                  * All resources are free'd explicitly via
1635                  * coresight_device_release(), triggered from put_device().
1636                  */
1637                 goto out_unlock;
1638         }
1639
1640         if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
1641             csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
1642                 ret = etm_perf_add_symlink_sink(csdev);
1643
1644                 if (ret) {
1645                         device_unregister(&csdev->dev);
1646                         /*
1647                          * As with the above, all resources are free'd
1648                          * explicitly via coresight_device_release() triggered
1649                          * from put_device(), which is in turn called from
1650                          * function device_unregister().
1651                          */
1652                         goto out_unlock;
1653                 }
1654         }
1655         /* Device is now registered */
1656         registered = true;
1657
1658         ret = coresight_create_conns_sysfs_group(csdev);
1659         if (!ret)
1660                 ret = coresight_fixup_device_conns(csdev);
1661         if (!ret)
1662                 ret = coresight_fixup_orphan_conns(csdev);
1663
1664 out_unlock:
1665         mutex_unlock(&coresight_mutex);
1666         /* Success */
1667         if (!ret) {
1668                 if (cti_assoc_ops && cti_assoc_ops->add)
1669                         cti_assoc_ops->add(csdev);
1670                 return csdev;
1671         }
1672
1673         /* Unregister the device if needed */
1674         if (registered) {
1675                 coresight_unregister(csdev);
1676                 return ERR_PTR(ret);
1677         }
1678
1679 err_out:
1680         /* Cleanup the connection information */
1681         coresight_release_platform_data(NULL, desc->pdata);
1682         return ERR_PTR(ret);
1683 }
1684 EXPORT_SYMBOL_GPL(coresight_register);
1685
1686 void coresight_unregister(struct coresight_device *csdev)
1687 {
1688         etm_perf_del_symlink_sink(csdev);
1689         /* Remove references of that device in the topology */
1690         if (cti_assoc_ops && cti_assoc_ops->remove)
1691                 cti_assoc_ops->remove(csdev);
1692         coresight_remove_conns(csdev);
1693         coresight_clear_default_sink(csdev);
1694         coresight_release_platform_data(csdev, csdev->pdata);
1695         device_unregister(&csdev->dev);
1696 }
1697 EXPORT_SYMBOL_GPL(coresight_unregister);
1698
1699
1700 /*
1701  * coresight_search_device_idx - Search the fwnode handle of a device
1702  * in the given dev_idx list. Must be called with the coresight_mutex held.
1703  *
1704  * Returns the index of the entry, when found. Otherwise, -ENOENT.
1705  */
1706 static inline int coresight_search_device_idx(struct coresight_dev_list *dict,
1707                                               struct fwnode_handle *fwnode)
1708 {
1709         int i;
1710
1711         for (i = 0; i < dict->nr_idx; i++)
1712                 if (dict->fwnode_list[i] == fwnode)
1713                         return i;
1714         return -ENOENT;
1715 }
1716
1717 bool coresight_loses_context_with_cpu(struct device *dev)
1718 {
1719         return fwnode_property_present(dev_fwnode(dev),
1720                                        "arm,coresight-loses-context-with-cpu");
1721 }
1722 EXPORT_SYMBOL_GPL(coresight_loses_context_with_cpu);
1723
1724 /*
1725  * coresight_alloc_device_name - Get an index for a given device in the
1726  * device index list specific to a driver. An index is allocated for a
1727  * device and is tracked with the fwnode_handle to prevent allocating
1728  * duplicate indices for the same device (e.g, if we defer probing of
1729  * a device due to dependencies), in case the index is requested again.
1730  */
1731 char *coresight_alloc_device_name(struct coresight_dev_list *dict,
1732                                   struct device *dev)
1733 {
1734         int idx;
1735         char *name = NULL;
1736         struct fwnode_handle **list;
1737
1738         mutex_lock(&coresight_mutex);
1739
1740         idx = coresight_search_device_idx(dict, dev_fwnode(dev));
1741         if (idx < 0) {
1742                 /* Make space for the new entry */
1743                 idx = dict->nr_idx;
1744                 list = krealloc_array(dict->fwnode_list,
1745                                       idx + 1, sizeof(*dict->fwnode_list),
1746                                       GFP_KERNEL);
1747                 if (ZERO_OR_NULL_PTR(list)) {
1748                         idx = -ENOMEM;
1749                         goto done;
1750                 }
1751
1752                 list[idx] = dev_fwnode(dev);
1753                 dict->fwnode_list = list;
1754                 dict->nr_idx = idx + 1;
1755         }
1756
1757         name = devm_kasprintf(dev, GFP_KERNEL, "%s%d", dict->pfx, idx);
1758 done:
1759         mutex_unlock(&coresight_mutex);
1760         return name;
1761 }
1762 EXPORT_SYMBOL_GPL(coresight_alloc_device_name);
1763
1764 struct bus_type coresight_bustype = {
1765         .name   = "coresight",
1766 };
1767
1768 static int __init coresight_init(void)
1769 {
1770         int ret;
1771
1772         ret = bus_register(&coresight_bustype);
1773         if (ret)
1774                 return ret;
1775
1776         ret = etm_perf_init();
1777         if (ret)
1778                 goto exit_bus_unregister;
1779
1780         /* initialise the coresight syscfg API */
1781         ret = cscfg_init();
1782         if (!ret)
1783                 return 0;
1784
1785         etm_perf_exit();
1786 exit_bus_unregister:
1787         bus_unregister(&coresight_bustype);
1788         return ret;
1789 }
1790
1791 static void __exit coresight_exit(void)
1792 {
1793         cscfg_exit();
1794         etm_perf_exit();
1795         bus_unregister(&coresight_bustype);
1796 }
1797
1798 module_init(coresight_init);
1799 module_exit(coresight_exit);
1800
1801 MODULE_LICENSE("GPL v2");
1802 MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
1803 MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
1804 MODULE_DESCRIPTION("Arm CoreSight tracer driver");