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