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