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