drivers/hwtracing/coresight/coresight.c

   1 /* Copyright (c) 2012, The Linux Foundation. All rights reserved.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License version 2 and
   5  * only version 2 as published by the Free Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/types.h>
  16 #include <linux/device.h>
  17 #include <linux/io.h>
  18 #include <linux/err.h>
  19 #include <linux/export.h>
  20 #include <linux/slab.h>
  21 #include <linux/mutex.h>
  22 #include <linux/clk.h>
  23 #include <linux/coresight.h>
  24 #include <linux/of_platform.h>
  25 #include <linux/delay.h>
  26 #include <linux/pm_runtime.h>
  27
  28 #include "coresight-priv.h"
  29
  30 static DEFINE_MUTEX(coresight_mutex);
  31
  32 /**
  33  * struct coresight_node - elements of a path, from source to sink
  34  * @csdev:      Address of an element.
  35  * @link:       hook to the list.
  36  */
  37 struct coresight_node {
  38         struct coresight_device *csdev;
  39         struct list_head link;
  40 };
  41
  42 /*
  43  * When operating Coresight drivers from the sysFS interface, only a single
  44  * path can exist from a tracer (associated to a CPU) to a sink.
  45  */
  46 static DEFINE_PER_CPU(struct list_head *, tracer_path);
  47
  48 /*
  49  * As of this writing only a single STM can be found in CS topologies.  Since
  50  * there is no way to know if we'll ever see more and what kind of
  51  * configuration they will enact, for the time being only define a single path
  52  * for STM.
  53  */
  54 static struct list_head *stm_path;
  55
  56 static int coresight_id_match(struct device *dev, void *data)
  57 {
  58         int trace_id, i_trace_id;
  59         struct coresight_device *csdev, *i_csdev;
  60
  61         csdev = data;
  62         i_csdev = to_coresight_device(dev);
  63
  64         /*
  65          * No need to care about oneself and components that are not
  66          * sources or not enabled
  67          */
  68         if (i_csdev == csdev || !i_csdev->enable ||
  69             i_csdev->type != CORESIGHT_DEV_TYPE_SOURCE)
  70                 return 0;
  71
  72         /* Get the source ID for both compoment */
  73         trace_id = source_ops(csdev)->trace_id(csdev);
  74         i_trace_id = source_ops(i_csdev)->trace_id(i_csdev);
  75
  76         /* All you need is one */
  77         if (trace_id == i_trace_id)
  78                 return 1;
  79
  80         return 0;
  81 }
  82
  83 static int coresight_source_is_unique(struct coresight_device *csdev)
  84 {
  85         int trace_id = source_ops(csdev)->trace_id(csdev);
  86
  87         /* this shouldn't happen */
  88         if (trace_id < 0)
  89                 return 0;
  90
  91         return !bus_for_each_dev(&coresight_bustype, NULL,
  92                                  csdev, coresight_id_match);
  93 }
  94
  95 static int coresight_find_link_inport(struct coresight_device *csdev,
  96                                       struct coresight_device *parent)
  97 {
  98         int i;
  99         struct coresight_connection *conn;
 100
 101         for (i = 0; i < parent->nr_outport; i++) {
 102                 conn = &parent->conns[i];
 103                 if (conn->child_dev == csdev)
 104                         return conn->child_port;
 105         }
 106
 107         dev_err(&csdev->dev, "couldn't find inport, parent: %s, child: %s\n",
 108                 dev_name(&parent->dev), dev_name(&csdev->dev));
 109
 110         return 0;
 111 }
 112
 113 static int coresight_find_link_outport(struct coresight_device *csdev,
 114                                        struct coresight_device *child)
 115 {
 116         int i;
 117         struct coresight_connection *conn;
 118
 119         for (i = 0; i < csdev->nr_outport; i++) {
 120                 conn = &csdev->conns[i];
 121                 if (conn->child_dev == child)
 122                         return conn->outport;
 123         }
 124
 125         dev_err(&csdev->dev, "couldn't find outport, parent: %s, child: %s\n",
 126                 dev_name(&csdev->dev), dev_name(&child->dev));
 127
 128         return 0;
 129 }
 130
 131 static int coresight_enable_sink(struct coresight_device *csdev, u32 mode)
 132 {
 133         int ret;
 134
 135         if (!csdev->enable) {
 136                 if (sink_ops(csdev)->enable) {
 137                         ret = sink_ops(csdev)->enable(csdev, mode);
 138                         if (ret)
 139                                 return ret;
 140                 }
 141                 csdev->enable = true;
 142         }
 143
 144         atomic_inc(csdev->refcnt);
 145
 146         return 0;
 147 }
 148
 149 static void coresight_disable_sink(struct coresight_device *csdev)
 150 {
 151         if (atomic_dec_return(csdev->refcnt) == 0) {
 152                 if (sink_ops(csdev)->disable) {
 153                         sink_ops(csdev)->disable(csdev);
 154                         csdev->enable = false;
 155                 }
 156         }
 157 }
 158
 159 static int coresight_enable_link(struct coresight_device *csdev,
 160                                  struct coresight_device *parent,
 161                                  struct coresight_device *child)
 162 {
 163         int ret;
 164         int link_subtype;
 165         int refport, inport, outport;
 166
 167         if (!parent || !child)
 168                 return -EINVAL;
 169
 170         inport = coresight_find_link_inport(csdev, parent);
 171         outport = coresight_find_link_outport(csdev, child);
 172         link_subtype = csdev->subtype.link_subtype;
 173
 174         if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
 175                 refport = inport;
 176         else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
 177                 refport = outport;
 178         else
 179                 refport = 0;
 180
 181         if (atomic_inc_return(&csdev->refcnt[refport]) == 1) {
 182                 if (link_ops(csdev)->enable) {
 183                         ret = link_ops(csdev)->enable(csdev, inport, outport);
 184                         if (ret)
 185                                 return ret;
 186                 }
 187         }
 188
 189         csdev->enable = true;
 190
 191         return 0;
 192 }
 193
 194 static void coresight_disable_link(struct coresight_device *csdev,
 195                                    struct coresight_device *parent,
 196                                    struct coresight_device *child)
 197 {
 198         int i, nr_conns;
 199         int link_subtype;
 200         int refport, inport, outport;
 201
 202         if (!parent || !child)
 203                 return;
 204
 205         inport = coresight_find_link_inport(csdev, parent);
 206         outport = coresight_find_link_outport(csdev, child);
 207         link_subtype = csdev->subtype.link_subtype;
 208
 209         if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
 210                 refport = inport;
 211                 nr_conns = csdev->nr_inport;
 212         } else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
 213                 refport = outport;
 214                 nr_conns = csdev->nr_outport;
 215         } else {
 216                 refport = 0;
 217                 nr_conns = 1;
 218         }
 219
 220         if (atomic_dec_return(&csdev->refcnt[refport]) == 0) {
 221                 if (link_ops(csdev)->disable)
 222                         link_ops(csdev)->disable(csdev, inport, outport);
 223         }
 224
 225         for (i = 0; i < nr_conns; i++)
 226                 if (atomic_read(&csdev->refcnt[i]) != 0)
 227                         return;
 228
 229         csdev->enable = false;
 230 }
 231
 232 static int coresight_enable_source(struct coresight_device *csdev, u32 mode)
 233 {
 234         int ret;
 235
 236         if (!coresight_source_is_unique(csdev)) {
 237                 dev_warn(&csdev->dev, "traceID %d not unique\n",
 238                          source_ops(csdev)->trace_id(csdev));
 239                 return -EINVAL;
 240         }
 241
 242         if (!csdev->enable) {
 243                 if (source_ops(csdev)->enable) {
 244                         ret = source_ops(csdev)->enable(csdev, NULL, mode);
 245                         if (ret)
 246                                 return ret;
 247                 }
 248                 csdev->enable = true;
 249         }
 250
 251         atomic_inc(csdev->refcnt);
 252
 253         return 0;
 254 }
 255
 256 static void coresight_disable_source(struct coresight_device *csdev)
 257 {
 258         if (atomic_dec_return(csdev->refcnt) == 0) {
 259                 if (source_ops(csdev)->disable) {
 260                         source_ops(csdev)->disable(csdev, NULL);
 261                         csdev->enable = false;
 262                 }
 263         }
 264 }
 265
 266 void coresight_disable_path(struct list_head *path)
 267 {
 268         u32 type;
 269         struct coresight_node *nd;
 270         struct coresight_device *csdev, *parent, *child;
 271
 272         list_for_each_entry(nd, path, link) {
 273                 csdev = nd->csdev;
 274                 type = csdev->type;
 275
 276                 /*
 277                  * ETF devices are tricky... They can be a link or a sink,
 278                  * depending on how they are configured.  If an ETF has been
 279                  * "activated" it will be configured as a sink, otherwise
 280                  * go ahead with the link configuration.
 281                  */
 282                 if (type == CORESIGHT_DEV_TYPE_LINKSINK)
 283                         type = (csdev == coresight_get_sink(path)) ?
 284                                                 CORESIGHT_DEV_TYPE_SINK :
 285                                                 CORESIGHT_DEV_TYPE_LINK;
 286
 287                 switch (type) {
 288                 case CORESIGHT_DEV_TYPE_SINK:
 289                         coresight_disable_sink(csdev);
 290                         break;
 291                 case CORESIGHT_DEV_TYPE_SOURCE:
 292                         /* sources are disabled from either sysFS or Perf */
 293                         break;
 294                 case CORESIGHT_DEV_TYPE_LINK:
 295                         parent = list_prev_entry(nd, link)->csdev;
 296                         child = list_next_entry(nd, link)->csdev;
 297                         coresight_disable_link(csdev, parent, child);
 298                         break;
 299                 default:
 300                         break;
 301                 }
 302         }
 303 }
 304
 305 int coresight_enable_path(struct list_head *path, u32 mode)
 306 {
 307
 308         int ret = 0;
 309         u32 type;
 310         struct coresight_node *nd;
 311         struct coresight_device *csdev, *parent, *child;
 312
 313         list_for_each_entry_reverse(nd, path, link) {
 314                 csdev = nd->csdev;
 315                 type = csdev->type;
 316
 317                 /*
 318                  * ETF devices are tricky... They can be a link or a sink,
 319                  * depending on how they are configured.  If an ETF has been
 320                  * "activated" it will be configured as a sink, otherwise
 321                  * go ahead with the link configuration.
 322                  */
 323                 if (type == CORESIGHT_DEV_TYPE_LINKSINK)
 324                         type = (csdev == coresight_get_sink(path)) ?
 325                                                 CORESIGHT_DEV_TYPE_SINK :
 326                                                 CORESIGHT_DEV_TYPE_LINK;
 327
 328                 switch (type) {
 329                 case CORESIGHT_DEV_TYPE_SINK:
 330                         ret = coresight_enable_sink(csdev, mode);
 331                         if (ret)
 332                                 goto err;
 333                         break;
 334                 case CORESIGHT_DEV_TYPE_SOURCE:
 335                         /* sources are enabled from either sysFS or Perf */
 336                         break;
 337                 case CORESIGHT_DEV_TYPE_LINK:
 338                         parent = list_prev_entry(nd, link)->csdev;
 339                         child = list_next_entry(nd, link)->csdev;
 340                         ret = coresight_enable_link(csdev, parent, child);
 341                         if (ret)
 342                                 goto err;
 343                         break;
 344                 default:
 345                         goto err;
 346                 }
 347         }
 348
 349 out:
 350         return ret;
 351 err:
 352         coresight_disable_path(path);
 353         goto out;
 354 }
 355
 356 struct coresight_device *coresight_get_sink(struct list_head *path)
 357 {
 358         struct coresight_device *csdev;
 359
 360         if (!path)
 361                 return NULL;
 362
 363         csdev = list_last_entry(path, struct coresight_node, link)->csdev;
 364         if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
 365             csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
 366                 return NULL;
 367
 368         return csdev;
 369 }
 370
 371 static int coresight_enabled_sink(struct device *dev, void *data)
 372 {
 373         bool *reset = data;
 374         struct coresight_device *csdev = to_coresight_device(dev);
 375
 376         if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
 377              csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
 378              csdev->activated) {
 379                 /*
 380                  * Now that we have a handle on the sink for this session,
 381                  * disable the sysFS "enable_sink" flag so that possible
 382                  * concurrent perf session that wish to use another sink don't
 383                  * trip on it.  Doing so has no ramification for the current
 384                  * session.
 385                  */
 386                 if (*reset)
 387                         csdev->activated = false;
 388
 389                 return 1;
 390         }
 391
 392         return 0;
 393 }
 394
 395 /**
 396  * coresight_get_enabled_sink - returns the first enabled sink found on the bus
 397  * @deactivate: Whether the 'enable_sink' flag should be reset
 398  *
 399  * When operated from perf the deactivate parameter should be set to 'true'.
 400  * That way the "enabled_sink" flag of the sink that was selected can be reset,
 401  * allowing for other concurrent perf sessions to choose a different sink.
 402  *
 403  * When operated from sysFS users have full control and as such the deactivate
 404  * parameter should be set to 'false', hence mandating users to explicitly
 405  * clear the flag.
 406  */
 407 struct coresight_device *coresight_get_enabled_sink(bool deactivate)
 408 {
 409         struct device *dev = NULL;
 410
 411         dev = bus_find_device(&coresight_bustype, NULL, &deactivate,
 412                               coresight_enabled_sink);
 413
 414         return dev ? to_coresight_device(dev) : NULL;
 415 }
 416
 417 /**
 418  * _coresight_build_path - recursively build a path from a @csdev to a sink.
 419  * @csdev:      The device to start from.
 420  * @path:       The list to add devices to.
 421  *
 422  * The tree of Coresight device is traversed until an activated sink is
 423  * found.  From there the sink is added to the list along with all the
 424  * devices that led to that point - the end result is a list from source
 425  * to sink. In that list the source is the first device and the sink the
 426  * last one.
 427  */
 428 static int _coresight_build_path(struct coresight_device *csdev,
 429                                  struct coresight_device *sink,
 430                                  struct list_head *path)
 431 {
 432         int i;
 433         bool found = false;
 434         struct coresight_node *node;
 435
 436         /* An activated sink has been found.  Enqueue the element */
 437         if (csdev == sink)
 438                 goto out;
 439
 440         /* Not a sink - recursively explore each port found on this element */
 441         for (i = 0; i < csdev->nr_outport; i++) {
 442                 struct coresight_device *child_dev = csdev->conns[i].child_dev;
 443
 444                 if (child_dev &&
 445                     _coresight_build_path(child_dev, sink, path) == 0) {
 446                         found = true;
 447                         break;
 448                 }
 449         }
 450
 451         if (!found)
 452                 return -ENODEV;
 453
 454 out:
 455         /*
 456          * A path from this element to a sink has been found.  The elements
 457          * leading to the sink are already enqueued, all that is left to do
 458          * is tell the PM runtime core we need this element and add a node
 459          * for it.
 460          */
 461         node = kzalloc(sizeof(struct coresight_node), GFP_KERNEL);
 462         if (!node)
 463                 return -ENOMEM;
 464
 465         node->csdev = csdev;
 466         list_add(&node->link, path);
 467         pm_runtime_get_sync(csdev->dev.parent);
 468
 469         return 0;
 470 }
 471
 472 struct list_head *coresight_build_path(struct coresight_device *source,
 473                                        struct coresight_device *sink)
 474 {
 475         struct list_head *path;
 476         int rc;
 477
 478         if (!sink)
 479                 return ERR_PTR(-EINVAL);
 480
 481         path = kzalloc(sizeof(struct list_head), GFP_KERNEL);
 482         if (!path)
 483                 return ERR_PTR(-ENOMEM);
 484
 485         INIT_LIST_HEAD(path);
 486
 487         rc = _coresight_build_path(source, sink, path);
 488         if (rc) {
 489                 kfree(path);
 490                 return ERR_PTR(rc);
 491         }
 492
 493         return path;
 494 }
 495
 496 /**
 497  * coresight_release_path - release a previously built path.
 498  * @path:       the path to release.
 499  *
 500  * Go through all the elements of a path and 1) removed it from the list and
 501  * 2) free the memory allocated for each node.
 502  */
 503 void coresight_release_path(struct list_head *path)
 504 {
 505         struct coresight_device *csdev;
 506         struct coresight_node *nd, *next;
 507
 508         list_for_each_entry_safe(nd, next, path, link) {
 509                 csdev = nd->csdev;
 510
 511                 pm_runtime_put_sync(csdev->dev.parent);
 512                 list_del(&nd->link);
 513                 kfree(nd);
 514         }
 515
 516         kfree(path);
 517         path = NULL;
 518 }
 519
 520 /** coresight_validate_source - make sure a source has the right credentials
 521  *  @csdev:     the device structure for a source.
 522  *  @function:  the function this was called from.
 523  *
 524  * Assumes the coresight_mutex is held.
 525  */
 526 static int coresight_validate_source(struct coresight_device *csdev,
 527                                      const char *function)
 528 {
 529         u32 type, subtype;
 530
 531         type = csdev->type;
 532         subtype = csdev->subtype.source_subtype;
 533
 534         if (type != CORESIGHT_DEV_TYPE_SOURCE) {
 535                 dev_err(&csdev->dev, "wrong device type in %s\n", function);
 536                 return -EINVAL;
 537         }
 538
 539         if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC &&
 540             subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE) {
 541                 dev_err(&csdev->dev, "wrong device subtype in %s\n", function);
 542                 return -EINVAL;
 543         }
 544
 545         return 0;
 546 }
 547
 548 int coresight_enable(struct coresight_device *csdev)
 549 {
 550         int cpu, ret = 0;
 551         struct coresight_device *sink;
 552         struct list_head *path;
 553
 554         mutex_lock(&coresight_mutex);
 555
 556         ret = coresight_validate_source(csdev, __func__);
 557         if (ret)
 558                 goto out;
 559
 560         if (csdev->enable)
 561                 goto out;
 562
 563         /*
 564          * Search for a valid sink for this session but don't reset the
 565          * "enable_sink" flag in sysFS.  Users get to do that explicitly.
 566          */
 567         sink = coresight_get_enabled_sink(false);
 568         if (!sink) {
 569                 ret = -EINVAL;
 570                 goto out;
 571         }
 572
 573         path = coresight_build_path(csdev, sink);
 574         if (IS_ERR(path)) {
 575                 pr_err("building path(s) failed\n");
 576                 ret = PTR_ERR(path);
 577                 goto out;
 578         }
 579
 580         ret = coresight_enable_path(path, CS_MODE_SYSFS);
 581         if (ret)
 582                 goto err_path;
 583
 584         ret = coresight_enable_source(csdev, CS_MODE_SYSFS);
 585         if (ret)
 586                 goto err_source;
 587
 588         switch (csdev->subtype.source_subtype) {
 589         case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
 590                 /*
 591                  * When working from sysFS it is important to keep track
 592                  * of the paths that were created so that they can be
 593                  * undone in 'coresight_disable()'.  Since there can only
 594                  * be a single session per tracer (when working from sysFS)
 595                  * a per-cpu variable will do just fine.
 596                  */
 597                 cpu = source_ops(csdev)->cpu_id(csdev);
 598                 per_cpu(tracer_path, cpu) = path;
 599                 break;
 600         case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
 601                 stm_path = path;
 602                 break;
 603         default:
 604                 /* We can't be here */
 605                 break;
 606         }
 607
 608 out:
 609         mutex_unlock(&coresight_mutex);
 610         return ret;
 611
 612 err_source:
 613         coresight_disable_path(path);
 614
 615 err_path:
 616         coresight_release_path(path);
 617         goto out;
 618 }
 619 EXPORT_SYMBOL_GPL(coresight_enable);
 620
 621 void coresight_disable(struct coresight_device *csdev)
 622 {
 623         int cpu, ret;
 624         struct list_head *path = NULL;
 625
 626         mutex_lock(&coresight_mutex);
 627
 628         ret = coresight_validate_source(csdev, __func__);
 629         if (ret)
 630                 goto out;
 631
 632         if (!csdev->enable)
 633                 goto out;
 634
 635         switch (csdev->subtype.source_subtype) {
 636         case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
 637                 cpu = source_ops(csdev)->cpu_id(csdev);
 638                 path = per_cpu(tracer_path, cpu);
 639                 per_cpu(tracer_path, cpu) = NULL;
 640                 break;
 641         case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
 642                 path = stm_path;
 643                 stm_path = NULL;
 644                 break;
 645         default:
 646                 /* We can't be here */
 647                 break;
 648         }
 649
 650         coresight_disable_source(csdev);
 651         coresight_disable_path(path);
 652         coresight_release_path(path);
 653
 654 out:
 655         mutex_unlock(&coresight_mutex);
 656 }
 657 EXPORT_SYMBOL_GPL(coresight_disable);
 658
 659 static ssize_t enable_sink_show(struct device *dev,
 660                                 struct device_attribute *attr, char *buf)
 661 {
 662         struct coresight_device *csdev = to_coresight_device(dev);
 663
 664         return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->activated);
 665 }
 666
 667 static ssize_t enable_sink_store(struct device *dev,
 668                                  struct device_attribute *attr,
 669                                  const char *buf, size_t size)
 670 {
 671         int ret;
 672         unsigned long val;
 673         struct coresight_device *csdev = to_coresight_device(dev);
 674
 675         ret = kstrtoul(buf, 10, &val);
 676         if (ret)
 677                 return ret;
 678
 679         if (val)
 680                 csdev->activated = true;
 681         else
 682                 csdev->activated = false;
 683
 684         return size;
 685
 686 }
 687 static DEVICE_ATTR_RW(enable_sink);
 688
 689 static ssize_t enable_source_show(struct device *dev,
 690                                   struct device_attribute *attr, char *buf)
 691 {
 692         struct coresight_device *csdev = to_coresight_device(dev);
 693
 694         return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->enable);
 695 }
 696
 697 static ssize_t enable_source_store(struct device *dev,
 698                                    struct device_attribute *attr,
 699                                    const char *buf, size_t size)
 700 {
 701         int ret = 0;
 702         unsigned long val;
 703         struct coresight_device *csdev = to_coresight_device(dev);
 704
 705         ret = kstrtoul(buf, 10, &val);
 706         if (ret)
 707                 return ret;
 708
 709         if (val) {
 710                 ret = coresight_enable(csdev);
 711                 if (ret)
 712                         return ret;
 713         } else {
 714                 coresight_disable(csdev);
 715         }
 716
 717         return size;
 718 }
 719 static DEVICE_ATTR_RW(enable_source);
 720
 721 static struct attribute *coresight_sink_attrs[] = {
 722         &dev_attr_enable_sink.attr,
 723         NULL,
 724 };
 725 ATTRIBUTE_GROUPS(coresight_sink);
 726
 727 static struct attribute *coresight_source_attrs[] = {
 728         &dev_attr_enable_source.attr,
 729         NULL,
 730 };
 731 ATTRIBUTE_GROUPS(coresight_source);
 732
 733 static struct device_type coresight_dev_type[] = {
 734         {
 735                 .name = "none",
 736         },
 737         {
 738                 .name = "sink",
 739                 .groups = coresight_sink_groups,
 740         },
 741         {
 742                 .name = "link",
 743         },
 744         {
 745                 .name = "linksink",
 746                 .groups = coresight_sink_groups,
 747         },
 748         {
 749                 .name = "source",
 750                 .groups = coresight_source_groups,
 751         },
 752 };
 753
 754 static void coresight_device_release(struct device *dev)
 755 {
 756         struct coresight_device *csdev = to_coresight_device(dev);
 757
 758         kfree(csdev->conns);
 759         kfree(csdev->refcnt);
 760         kfree(csdev);
 761 }
 762
 763 static int coresight_orphan_match(struct device *dev, void *data)
 764 {
 765         int i;
 766         bool still_orphan = false;
 767         struct coresight_device *csdev, *i_csdev;
 768         struct coresight_connection *conn;
 769
 770         csdev = data;
 771         i_csdev = to_coresight_device(dev);
 772
 773         /* No need to check oneself */
 774         if (csdev == i_csdev)
 775                 return 0;
 776
 777         /* Move on to another component if no connection is orphan */
 778         if (!i_csdev->orphan)
 779                 return 0;
 780         /*
 781          * Circle throuch all the connection of that component.  If we find
 782          * an orphan connection whose name matches @csdev, link it.
 783          */
 784         for (i = 0; i < i_csdev->nr_outport; i++) {
 785                 conn = &i_csdev->conns[i];
 786
 787                 /* We have found at least one orphan connection */
 788                 if (conn->child_dev == NULL) {
 789                         /* Does it match this newly added device? */
 790                         if (conn->child_name &&
 791                             !strcmp(dev_name(&csdev->dev), conn->child_name)) {
 792                                 conn->child_dev = csdev;
 793                         } else {
 794                                 /* This component still has an orphan */
 795                                 still_orphan = true;
 796                         }
 797                 }
 798         }
 799
 800         i_csdev->orphan = still_orphan;
 801
 802         /*
 803          * Returning '0' ensures that all known component on the
 804          * bus will be checked.
 805          */
 806         return 0;
 807 }
 808
 809 static void coresight_fixup_orphan_conns(struct coresight_device *csdev)
 810 {
 811         /*
 812          * No need to check for a return value as orphan connection(s)
 813          * are hooked-up with each newly added component.
 814          */
 815         bus_for_each_dev(&coresight_bustype, NULL,
 816                          csdev, coresight_orphan_match);
 817 }
 818
 819
 820 static int coresight_name_match(struct device *dev, void *data)
 821 {
 822         char *to_match;
 823         struct coresight_device *i_csdev;
 824
 825         to_match = data;
 826         i_csdev = to_coresight_device(dev);
 827
 828         if (to_match && !strcmp(to_match, dev_name(&i_csdev->dev)))
 829                 return 1;
 830
 831         return 0;
 832 }
 833
 834 static void coresight_fixup_device_conns(struct coresight_device *csdev)
 835 {
 836         int i;
 837         struct device *dev = NULL;
 838         struct coresight_connection *conn;
 839
 840         for (i = 0; i < csdev->nr_outport; i++) {
 841                 conn = &csdev->conns[i];
 842                 dev = bus_find_device(&coresight_bustype, NULL,
 843                                       (void *)conn->child_name,
 844                                       coresight_name_match);
 845
 846                 if (dev) {
 847                         conn->child_dev = to_coresight_device(dev);
 848                         /* and put reference from 'bus_find_device()' */
 849                         put_device(dev);
 850                 } else {
 851                         csdev->orphan = true;
 852                         conn->child_dev = NULL;
 853                 }
 854         }
 855 }
 856
 857 static int coresight_remove_match(struct device *dev, void *data)
 858 {
 859         int i;
 860         struct coresight_device *csdev, *iterator;
 861         struct coresight_connection *conn;
 862
 863         csdev = data;
 864         iterator = to_coresight_device(dev);
 865
 866         /* No need to check oneself */
 867         if (csdev == iterator)
 868                 return 0;
 869
 870         /*
 871          * Circle throuch all the connection of that component.  If we find
 872          * a connection whose name matches @csdev, remove it.
 873          */
 874         for (i = 0; i < iterator->nr_outport; i++) {
 875                 conn = &iterator->conns[i];
 876
 877                 if (conn->child_dev == NULL)
 878                         continue;
 879
 880                 if (!strcmp(dev_name(&csdev->dev), conn->child_name)) {
 881                         iterator->orphan = true;
 882                         conn->child_dev = NULL;
 883                         /* No need to continue */
 884                         break;
 885                 }
 886         }
 887
 888         /*
 889          * Returning '0' ensures that all known component on the
 890          * bus will be checked.
 891          */
 892         return 0;
 893 }
 894
 895 static void coresight_remove_conns(struct coresight_device *csdev)
 896 {
 897         bus_for_each_dev(&coresight_bustype, NULL,
 898                          csdev, coresight_remove_match);
 899 }
 900
 901 /**
 902  * coresight_timeout - loop until a bit has changed to a specific state.
 903  * @addr: base address of the area of interest.
 904  * @offset: address of a register, starting from @addr.
 905  * @position: the position of the bit of interest.
 906  * @value: the value the bit should have.
 907  *
 908  * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
 909  * TIMEOUT_US has elapsed, which ever happens first.
 910  */
 911
 912 int coresight_timeout(void __iomem *addr, u32 offset, int position, int value)
 913 {
 914         int i;
 915         u32 val;
 916
 917         for (i = TIMEOUT_US; i > 0; i--) {
 918                 val = __raw_readl(addr + offset);
 919                 /* waiting on the bit to go from 0 to 1 */
 920                 if (value) {
 921                         if (val & BIT(position))
 922                                 return 0;
 923                 /* waiting on the bit to go from 1 to 0 */
 924                 } else {
 925                         if (!(val & BIT(position)))
 926                                 return 0;
 927                 }
 928
 929                 /*
 930                  * Delay is arbitrary - the specification doesn't say how long
 931                  * we are expected to wait.  Extra check required to make sure
 932                  * we don't wait needlessly on the last iteration.
 933                  */
 934                 if (i - 1)
 935                         udelay(1);
 936         }
 937
 938         return -EAGAIN;
 939 }
 940
 941 struct bus_type coresight_bustype = {
 942         .name   = "coresight",
 943 };
 944
 945 static int __init coresight_init(void)
 946 {
 947         return bus_register(&coresight_bustype);
 948 }
 949 postcore_initcall(coresight_init);
 950
 951 struct coresight_device *coresight_register(struct coresight_desc *desc)
 952 {
 953         int i;
 954         int ret;
 955         int link_subtype;
 956         int nr_refcnts = 1;
 957         atomic_t *refcnts = NULL;
 958         struct coresight_device *csdev;
 959         struct coresight_connection *conns = NULL;
 960
 961         csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
 962         if (!csdev) {
 963                 ret = -ENOMEM;
 964                 goto err_kzalloc_csdev;
 965         }
 966
 967         if (desc->type == CORESIGHT_DEV_TYPE_LINK ||
 968             desc->type == CORESIGHT_DEV_TYPE_LINKSINK) {
 969                 link_subtype = desc->subtype.link_subtype;
 970
 971                 if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
 972                         nr_refcnts = desc->pdata->nr_inport;
 973                 else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
 974                         nr_refcnts = desc->pdata->nr_outport;
 975         }
 976
 977         refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
 978         if (!refcnts) {
 979                 ret = -ENOMEM;
 980                 goto err_kzalloc_refcnts;
 981         }
 982
 983         csdev->refcnt = refcnts;
 984
 985         csdev->nr_inport = desc->pdata->nr_inport;
 986         csdev->nr_outport = desc->pdata->nr_outport;
 987
 988         /* Initialise connections if there is at least one outport */
 989         if (csdev->nr_outport) {
 990                 conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
 991                 if (!conns) {
 992                         ret = -ENOMEM;
 993                         goto err_kzalloc_conns;
 994                 }
 995
 996                 for (i = 0; i < csdev->nr_outport; i++) {
 997                         conns[i].outport = desc->pdata->outports[i];
 998                         conns[i].child_name = desc->pdata->child_names[i];
 999                         conns[i].child_port = desc->pdata->child_ports[i];
1000                 }
1001         }
1002
1003         csdev->conns = conns;
1004
1005         csdev->type = desc->type;
1006         csdev->subtype = desc->subtype;
1007         csdev->ops = desc->ops;
1008         csdev->orphan = false;
1009
1010         csdev->dev.type = &coresight_dev_type[desc->type];
1011         csdev->dev.groups = desc->groups;
1012         csdev->dev.parent = desc->dev;
1013         csdev->dev.release = coresight_device_release;
1014         csdev->dev.bus = &coresight_bustype;
1015         dev_set_name(&csdev->dev, "%s", desc->pdata->name);
1016
1017         ret = device_register(&csdev->dev);
1018         if (ret)
1019                 goto err_device_register;
1020
1021         mutex_lock(&coresight_mutex);
1022
1023         coresight_fixup_device_conns(csdev);
1024         coresight_fixup_orphan_conns(csdev);
1025
1026         mutex_unlock(&coresight_mutex);
1027
1028         return csdev;
1029
1030 err_device_register:
1031         kfree(conns);
1032 err_kzalloc_conns:
1033         kfree(refcnts);
1034 err_kzalloc_refcnts:
1035         kfree(csdev);
1036 err_kzalloc_csdev:
1037         return ERR_PTR(ret);
1038 }
1039 EXPORT_SYMBOL_GPL(coresight_register);
1040
1041 void coresight_unregister(struct coresight_device *csdev)
1042 {
1043         /* Remove references of that device in the topology */
1044         coresight_remove_conns(csdev);
1045         device_unregister(&csdev->dev);
1046 }
1047 EXPORT_SYMBOL_GPL(coresight_unregister);