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);
 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 /**
 372  * _coresight_build_path - recursively build a path from a @csdev to a sink.
 373  * @csdev:      The device to start from.
 374  * @path:       The list to add devices to.
 375  *
 376  * The tree of Coresight device is traversed until an activated sink is
 377  * found.  From there the sink is added to the list along with all the
 378  * devices that led to that point - the end result is a list from source
 379  * to sink. In that list the source is the first device and the sink the
 380  * last one.
 381  */
 382 static int _coresight_build_path(struct coresight_device *csdev,
 383                                  struct list_head *path)
 384 {
 385         int i;
 386         bool found = false;
 387         struct coresight_node *node;
 388
 389         /* An activated sink has been found.  Enqueue the element */
 390         if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
 391              csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) && csdev->activated)
 392                 goto out;
 393
 394         /* Not a sink - recursively explore each port found on this element */
 395         for (i = 0; i < csdev->nr_outport; i++) {
 396                 struct coresight_device *child_dev = csdev->conns[i].child_dev;
 397
 398                 if (child_dev && _coresight_build_path(child_dev, path) == 0) {
 399                         found = true;
 400                         break;
 401                 }
 402         }
 403
 404         if (!found)
 405                 return -ENODEV;
 406
 407 out:
 408         /*
 409          * A path from this element to a sink has been found.  The elements
 410          * leading to the sink are already enqueued, all that is left to do
 411          * is tell the PM runtime core we need this element and add a node
 412          * for it.
 413          */
 414         node = kzalloc(sizeof(struct coresight_node), GFP_KERNEL);
 415         if (!node)
 416                 return -ENOMEM;
 417
 418         node->csdev = csdev;
 419         list_add(&node->link, path);
 420         pm_runtime_get_sync(csdev->dev.parent);
 421
 422         return 0;
 423 }
 424
 425 struct list_head *coresight_build_path(struct coresight_device *csdev)
 426 {
 427         struct list_head *path;
 428         int rc;
 429
 430         path = kzalloc(sizeof(struct list_head), GFP_KERNEL);
 431         if (!path)
 432                 return NULL;
 433
 434         INIT_LIST_HEAD(path);
 435
 436         rc = _coresight_build_path(csdev, path);
 437         if (rc) {
 438                 kfree(path);
 439                 return ERR_PTR(rc);
 440         }
 441
 442         return path;
 443 }
 444
 445 /**
 446  * coresight_release_path - release a previously built path.
 447  * @path:       the path to release.
 448  *
 449  * Go through all the elements of a path and 1) removed it from the list and
 450  * 2) free the memory allocated for each node.
 451  */
 452 void coresight_release_path(struct list_head *path)
 453 {
 454         struct coresight_device *csdev;
 455         struct coresight_node *nd, *next;
 456
 457         list_for_each_entry_safe(nd, next, path, link) {
 458                 csdev = nd->csdev;
 459
 460                 pm_runtime_put_sync(csdev->dev.parent);
 461                 list_del(&nd->link);
 462                 kfree(nd);
 463         }
 464
 465         kfree(path);
 466         path = NULL;
 467 }
 468
 469 /** coresight_validate_source - make sure a source has the right credentials
 470  *  @csdev:     the device structure for a source.
 471  *  @function:  the function this was called from.
 472  *
 473  * Assumes the coresight_mutex is held.
 474  */
 475 static int coresight_validate_source(struct coresight_device *csdev,
 476                                      const char *function)
 477 {
 478         u32 type, subtype;
 479
 480         type = csdev->type;
 481         subtype = csdev->subtype.source_subtype;
 482
 483         if (type != CORESIGHT_DEV_TYPE_SOURCE) {
 484                 dev_err(&csdev->dev, "wrong device type in %s\n", function);
 485                 return -EINVAL;
 486         }
 487
 488         if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC &&
 489             subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE) {
 490                 dev_err(&csdev->dev, "wrong device subtype in %s\n", function);
 491                 return -EINVAL;
 492         }
 493
 494         return 0;
 495 }
 496
 497 int coresight_enable(struct coresight_device *csdev)
 498 {
 499         int cpu, ret = 0;
 500         struct list_head *path;
 501
 502         mutex_lock(&coresight_mutex);
 503
 504         ret = coresight_validate_source(csdev, __func__);
 505         if (ret)
 506                 goto out;
 507
 508         if (csdev->enable)
 509                 goto out;
 510
 511         path = coresight_build_path(csdev);
 512         if (IS_ERR(path)) {
 513                 pr_err("building path(s) failed\n");
 514                 ret = PTR_ERR(path);
 515                 goto out;
 516         }
 517
 518         ret = coresight_enable_path(path, CS_MODE_SYSFS);
 519         if (ret)
 520                 goto err_path;
 521
 522         ret = coresight_enable_source(csdev, CS_MODE_SYSFS);
 523         if (ret)
 524                 goto err_source;
 525
 526         switch (csdev->subtype.source_subtype) {
 527         case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
 528                 /*
 529                  * When working from sysFS it is important to keep track
 530                  * of the paths that were created so that they can be
 531                  * undone in 'coresight_disable()'.  Since there can only
 532                  * be a single session per tracer (when working from sysFS)
 533                  * a per-cpu variable will do just fine.
 534                  */
 535                 cpu = source_ops(csdev)->cpu_id(csdev);
 536                 per_cpu(tracer_path, cpu) = path;
 537                 break;
 538         case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
 539                 stm_path = path;
 540                 break;
 541         default:
 542                 /* We can't be here */
 543                 break;
 544         }
 545
 546 out:
 547         mutex_unlock(&coresight_mutex);
 548         return ret;
 549
 550 err_source:
 551         coresight_disable_path(path);
 552
 553 err_path:
 554         coresight_release_path(path);
 555         goto out;
 556 }
 557 EXPORT_SYMBOL_GPL(coresight_enable);
 558
 559 void coresight_disable(struct coresight_device *csdev)
 560 {
 561         int cpu, ret;
 562         struct list_head *path = NULL;
 563
 564         mutex_lock(&coresight_mutex);
 565
 566         ret = coresight_validate_source(csdev, __func__);
 567         if (ret)
 568                 goto out;
 569
 570         if (!csdev->enable)
 571                 goto out;
 572
 573         switch (csdev->subtype.source_subtype) {
 574         case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
 575                 cpu = source_ops(csdev)->cpu_id(csdev);
 576                 path = per_cpu(tracer_path, cpu);
 577                 per_cpu(tracer_path, cpu) = NULL;
 578                 break;
 579         case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
 580                 path = stm_path;
 581                 stm_path = NULL;
 582                 break;
 583         default:
 584                 /* We can't be here */
 585                 break;
 586         }
 587
 588         coresight_disable_source(csdev);
 589         coresight_disable_path(path);
 590         coresight_release_path(path);
 591
 592 out:
 593         mutex_unlock(&coresight_mutex);
 594 }
 595 EXPORT_SYMBOL_GPL(coresight_disable);
 596
 597 static ssize_t enable_sink_show(struct device *dev,
 598                                 struct device_attribute *attr, char *buf)
 599 {
 600         struct coresight_device *csdev = to_coresight_device(dev);
 601
 602         return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->activated);
 603 }
 604
 605 static ssize_t enable_sink_store(struct device *dev,
 606                                  struct device_attribute *attr,
 607                                  const char *buf, size_t size)
 608 {
 609         int ret;
 610         unsigned long val;
 611         struct coresight_device *csdev = to_coresight_device(dev);
 612
 613         ret = kstrtoul(buf, 10, &val);
 614         if (ret)
 615                 return ret;
 616
 617         if (val)
 618                 csdev->activated = true;
 619         else
 620                 csdev->activated = false;
 621
 622         return size;
 623
 624 }
 625 static DEVICE_ATTR_RW(enable_sink);
 626
 627 static ssize_t enable_source_show(struct device *dev,
 628                                   struct device_attribute *attr, char *buf)
 629 {
 630         struct coresight_device *csdev = to_coresight_device(dev);
 631
 632         return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->enable);
 633 }
 634
 635 static ssize_t enable_source_store(struct device *dev,
 636                                    struct device_attribute *attr,
 637                                    const char *buf, size_t size)
 638 {
 639         int ret = 0;
 640         unsigned long val;
 641         struct coresight_device *csdev = to_coresight_device(dev);
 642
 643         ret = kstrtoul(buf, 10, &val);
 644         if (ret)
 645                 return ret;
 646
 647         if (val) {
 648                 ret = coresight_enable(csdev);
 649                 if (ret)
 650                         return ret;
 651         } else {
 652                 coresight_disable(csdev);
 653         }
 654
 655         return size;
 656 }
 657 static DEVICE_ATTR_RW(enable_source);
 658
 659 static struct attribute *coresight_sink_attrs[] = {
 660         &dev_attr_enable_sink.attr,
 661         NULL,
 662 };
 663 ATTRIBUTE_GROUPS(coresight_sink);
 664
 665 static struct attribute *coresight_source_attrs[] = {
 666         &dev_attr_enable_source.attr,
 667         NULL,
 668 };
 669 ATTRIBUTE_GROUPS(coresight_source);
 670
 671 static struct device_type coresight_dev_type[] = {
 672         {
 673                 .name = "none",
 674         },
 675         {
 676                 .name = "sink",
 677                 .groups = coresight_sink_groups,
 678         },
 679         {
 680                 .name = "link",
 681         },
 682         {
 683                 .name = "linksink",
 684                 .groups = coresight_sink_groups,
 685         },
 686         {
 687                 .name = "source",
 688                 .groups = coresight_source_groups,
 689         },
 690 };
 691
 692 static void coresight_device_release(struct device *dev)
 693 {
 694         struct coresight_device *csdev = to_coresight_device(dev);
 695
 696         kfree(csdev->conns);
 697         kfree(csdev->refcnt);
 698         kfree(csdev);
 699 }
 700
 701 static int coresight_orphan_match(struct device *dev, void *data)
 702 {
 703         int i;
 704         bool still_orphan = false;
 705         struct coresight_device *csdev, *i_csdev;
 706         struct coresight_connection *conn;
 707
 708         csdev = data;
 709         i_csdev = to_coresight_device(dev);
 710
 711         /* No need to check oneself */
 712         if (csdev == i_csdev)
 713                 return 0;
 714
 715         /* Move on to another component if no connection is orphan */
 716         if (!i_csdev->orphan)
 717                 return 0;
 718         /*
 719          * Circle throuch all the connection of that component.  If we find
 720          * an orphan connection whose name matches @csdev, link it.
 721          */
 722         for (i = 0; i < i_csdev->nr_outport; i++) {
 723                 conn = &i_csdev->conns[i];
 724
 725                 /* We have found at least one orphan connection */
 726                 if (conn->child_dev == NULL) {
 727                         /* Does it match this newly added device? */
 728                         if (!strcmp(dev_name(&csdev->dev), conn->child_name)) {
 729                                 conn->child_dev = csdev;
 730                         } else {
 731                                 /* This component still has an orphan */
 732                                 still_orphan = true;
 733                         }
 734                 }
 735         }
 736
 737         i_csdev->orphan = still_orphan;
 738
 739         /*
 740          * Returning '0' ensures that all known component on the
 741          * bus will be checked.
 742          */
 743         return 0;
 744 }
 745
 746 static void coresight_fixup_orphan_conns(struct coresight_device *csdev)
 747 {
 748         /*
 749          * No need to check for a return value as orphan connection(s)
 750          * are hooked-up with each newly added component.
 751          */
 752         bus_for_each_dev(&coresight_bustype, NULL,
 753                          csdev, coresight_orphan_match);
 754 }
 755
 756
 757 static int coresight_name_match(struct device *dev, void *data)
 758 {
 759         char *to_match;
 760         struct coresight_device *i_csdev;
 761
 762         to_match = data;
 763         i_csdev = to_coresight_device(dev);
 764
 765         if (to_match && !strcmp(to_match, dev_name(&i_csdev->dev)))
 766                 return 1;
 767
 768         return 0;
 769 }
 770
 771 static void coresight_fixup_device_conns(struct coresight_device *csdev)
 772 {
 773         int i;
 774         struct device *dev = NULL;
 775         struct coresight_connection *conn;
 776
 777         for (i = 0; i < csdev->nr_outport; i++) {
 778                 conn = &csdev->conns[i];
 779                 dev = bus_find_device(&coresight_bustype, NULL,
 780                                       (void *)conn->child_name,
 781                                       coresight_name_match);
 782
 783                 if (dev) {
 784                         conn->child_dev = to_coresight_device(dev);
 785                         /* and put reference from 'bus_find_device()' */
 786                         put_device(dev);
 787                 } else {
 788                         csdev->orphan = true;
 789                         conn->child_dev = NULL;
 790                 }
 791         }
 792 }
 793
 794 static int coresight_remove_match(struct device *dev, void *data)
 795 {
 796         int i;
 797         struct coresight_device *csdev, *iterator;
 798         struct coresight_connection *conn;
 799
 800         csdev = data;
 801         iterator = to_coresight_device(dev);
 802
 803         /* No need to check oneself */
 804         if (csdev == iterator)
 805                 return 0;
 806
 807         /*
 808          * Circle throuch all the connection of that component.  If we find
 809          * a connection whose name matches @csdev, remove it.
 810          */
 811         for (i = 0; i < iterator->nr_outport; i++) {
 812                 conn = &iterator->conns[i];
 813
 814                 if (conn->child_dev == NULL)
 815                         continue;
 816
 817                 if (!strcmp(dev_name(&csdev->dev), conn->child_name)) {
 818                         iterator->orphan = true;
 819                         conn->child_dev = NULL;
 820                         /* No need to continue */
 821                         break;
 822                 }
 823         }
 824
 825         /*
 826          * Returning '0' ensures that all known component on the
 827          * bus will be checked.
 828          */
 829         return 0;
 830 }
 831
 832 static void coresight_remove_conns(struct coresight_device *csdev)
 833 {
 834         bus_for_each_dev(&coresight_bustype, NULL,
 835                          csdev, coresight_remove_match);
 836 }
 837
 838 /**
 839  * coresight_timeout - loop until a bit has changed to a specific state.
 840  * @addr: base address of the area of interest.
 841  * @offset: address of a register, starting from @addr.
 842  * @position: the position of the bit of interest.
 843  * @value: the value the bit should have.
 844  *
 845  * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
 846  * TIMEOUT_US has elapsed, which ever happens first.
 847  */
 848
 849 int coresight_timeout(void __iomem *addr, u32 offset, int position, int value)
 850 {
 851         int i;
 852         u32 val;
 853
 854         for (i = TIMEOUT_US; i > 0; i--) {
 855                 val = __raw_readl(addr + offset);
 856                 /* waiting on the bit to go from 0 to 1 */
 857                 if (value) {
 858                         if (val & BIT(position))
 859                                 return 0;
 860                 /* waiting on the bit to go from 1 to 0 */
 861                 } else {
 862                         if (!(val & BIT(position)))
 863                                 return 0;
 864                 }
 865
 866                 /*
 867                  * Delay is arbitrary - the specification doesn't say how long
 868                  * we are expected to wait.  Extra check required to make sure
 869                  * we don't wait needlessly on the last iteration.
 870                  */
 871                 if (i - 1)
 872                         udelay(1);
 873         }
 874
 875         return -EAGAIN;
 876 }
 877
 878 struct bus_type coresight_bustype = {
 879         .name   = "coresight",
 880 };
 881
 882 static int __init coresight_init(void)
 883 {
 884         return bus_register(&coresight_bustype);
 885 }
 886 postcore_initcall(coresight_init);
 887
 888 struct coresight_device *coresight_register(struct coresight_desc *desc)
 889 {
 890         int i;
 891         int ret;
 892         int link_subtype;
 893         int nr_refcnts = 1;
 894         atomic_t *refcnts = NULL;
 895         struct coresight_device *csdev;
 896         struct coresight_connection *conns;
 897
 898         csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
 899         if (!csdev) {
 900                 ret = -ENOMEM;
 901                 goto err_kzalloc_csdev;
 902         }
 903
 904         if (desc->type == CORESIGHT_DEV_TYPE_LINK ||
 905             desc->type == CORESIGHT_DEV_TYPE_LINKSINK) {
 906                 link_subtype = desc->subtype.link_subtype;
 907
 908                 if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
 909                         nr_refcnts = desc->pdata->nr_inport;
 910                 else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
 911                         nr_refcnts = desc->pdata->nr_outport;
 912         }
 913
 914         refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
 915         if (!refcnts) {
 916                 ret = -ENOMEM;
 917                 goto err_kzalloc_refcnts;
 918         }
 919
 920         csdev->refcnt = refcnts;
 921
 922         csdev->nr_inport = desc->pdata->nr_inport;
 923         csdev->nr_outport = desc->pdata->nr_outport;
 924         conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
 925         if (!conns) {
 926                 ret = -ENOMEM;
 927                 goto err_kzalloc_conns;
 928         }
 929
 930         for (i = 0; i < csdev->nr_outport; i++) {
 931                 conns[i].outport = desc->pdata->outports[i];
 932                 conns[i].child_name = desc->pdata->child_names[i];
 933                 conns[i].child_port = desc->pdata->child_ports[i];
 934         }
 935
 936         csdev->conns = conns;
 937
 938         csdev->type = desc->type;
 939         csdev->subtype = desc->subtype;
 940         csdev->ops = desc->ops;
 941         csdev->orphan = false;
 942
 943         csdev->dev.type = &coresight_dev_type[desc->type];
 944         csdev->dev.groups = desc->groups;
 945         csdev->dev.parent = desc->dev;
 946         csdev->dev.release = coresight_device_release;
 947         csdev->dev.bus = &coresight_bustype;
 948         dev_set_name(&csdev->dev, "%s", desc->pdata->name);
 949
 950         ret = device_register(&csdev->dev);
 951         if (ret)
 952                 goto err_device_register;
 953
 954         mutex_lock(&coresight_mutex);
 955
 956         coresight_fixup_device_conns(csdev);
 957         coresight_fixup_orphan_conns(csdev);
 958
 959         mutex_unlock(&coresight_mutex);
 960
 961         return csdev;
 962
 963 err_device_register:
 964         kfree(conns);
 965 err_kzalloc_conns:
 966         kfree(refcnts);
 967 err_kzalloc_refcnts:
 968         kfree(csdev);
 969 err_kzalloc_csdev:
 970         return ERR_PTR(ret);
 971 }
 972 EXPORT_SYMBOL_GPL(coresight_register);
 973
 974 void coresight_unregister(struct coresight_device *csdev)
 975 {
 976         /* Remove references of that device in the topology */
 977         coresight_remove_conns(csdev);
 978         device_unregister(&csdev->dev);
 979 }
 980 EXPORT_SYMBOL_GPL(coresight_unregister);