drivers/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/module.h>
  15 #include <linux/init.h>
  16 #include <linux/types.h>
  17 #include <linux/device.h>
  18 #include <linux/io.h>
  19 #include <linux/err.h>
  20 #include <linux/export.h>
  21 #include <linux/slab.h>
  22 #include <linux/mutex.h>
  23 #include <linux/clk.h>
  24 #include <linux/coresight.h>
  25 #include <linux/of_platform.h>
  26 #include <linux/delay.h>
  27
  28 #include "coresight-priv.h"
  29
  30 static DEFINE_MUTEX(coresight_mutex);
  31
  32 static int coresight_id_match(struct device *dev, void *data)
  33 {
  34         int trace_id, i_trace_id;
  35         struct coresight_device *csdev, *i_csdev;
  36
  37         csdev = data;
  38         i_csdev = to_coresight_device(dev);
  39
  40         /*
  41          * No need to care about oneself and components that are not
  42          * sources or not enabled
  43          */
  44         if (i_csdev == csdev || !i_csdev->enable ||
  45             i_csdev->type != CORESIGHT_DEV_TYPE_SOURCE)
  46                 return 0;
  47
  48         /* Get the source ID for both compoment */
  49         trace_id = source_ops(csdev)->trace_id(csdev);
  50         i_trace_id = source_ops(i_csdev)->trace_id(i_csdev);
  51
  52         /* All you need is one */
  53         if (trace_id == i_trace_id)
  54                 return 1;
  55
  56         return 0;
  57 }
  58
  59 static int coresight_source_is_unique(struct coresight_device *csdev)
  60 {
  61         int trace_id = source_ops(csdev)->trace_id(csdev);
  62
  63         /* this shouldn't happen */
  64         if (trace_id < 0)
  65                 return 0;
  66
  67         return !bus_for_each_dev(&coresight_bustype, NULL,
  68                                  csdev, coresight_id_match);
  69 }
  70
  71 static int coresight_find_link_inport(struct coresight_device *csdev)
  72 {
  73         int i;
  74         struct coresight_device *parent;
  75         struct coresight_connection *conn;
  76
  77         parent = container_of(csdev->path_link.next,
  78                               struct coresight_device, path_link);
  79
  80         for (i = 0; i < parent->nr_outport; i++) {
  81                 conn = &parent->conns[i];
  82                 if (conn->child_dev == csdev)
  83                         return conn->child_port;
  84         }
  85
  86         dev_err(&csdev->dev, "couldn't find inport, parent: %s, child: %s\n",
  87                 dev_name(&parent->dev), dev_name(&csdev->dev));
  88
  89         return 0;
  90 }
  91
  92 static int coresight_find_link_outport(struct coresight_device *csdev)
  93 {
  94         int i;
  95         struct coresight_device *child;
  96         struct coresight_connection *conn;
  97
  98         child = container_of(csdev->path_link.prev,
  99                              struct coresight_device, path_link);
 100
 101         for (i = 0; i < csdev->nr_outport; i++) {
 102                 conn = &csdev->conns[i];
 103                 if (conn->child_dev == child)
 104                         return conn->outport;
 105         }
 106
 107         dev_err(&csdev->dev, "couldn't find outport, parent: %s, child: %s\n",
 108                 dev_name(&csdev->dev), dev_name(&child->dev));
 109
 110         return 0;
 111 }
 112
 113 static int coresight_enable_sink(struct coresight_device *csdev)
 114 {
 115         int ret;
 116
 117         if (!csdev->enable) {
 118                 if (sink_ops(csdev)->enable) {
 119                         ret = sink_ops(csdev)->enable(csdev);
 120                         if (ret)
 121                                 return ret;
 122                 }
 123                 csdev->enable = true;
 124         }
 125
 126         atomic_inc(csdev->refcnt);
 127
 128         return 0;
 129 }
 130
 131 static void coresight_disable_sink(struct coresight_device *csdev)
 132 {
 133         if (atomic_dec_return(csdev->refcnt) == 0) {
 134                 if (sink_ops(csdev)->disable) {
 135                         sink_ops(csdev)->disable(csdev);
 136                         csdev->enable = false;
 137                 }
 138         }
 139 }
 140
 141 static int coresight_enable_link(struct coresight_device *csdev)
 142 {
 143         int ret;
 144         int link_subtype;
 145         int refport, inport, outport;
 146
 147         inport = coresight_find_link_inport(csdev);
 148         outport = coresight_find_link_outport(csdev);
 149         link_subtype = csdev->subtype.link_subtype;
 150
 151         if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
 152                 refport = inport;
 153         else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
 154                 refport = outport;
 155         else
 156                 refport = 0;
 157
 158         if (atomic_inc_return(&csdev->refcnt[refport]) == 1) {
 159                 if (link_ops(csdev)->enable) {
 160                         ret = link_ops(csdev)->enable(csdev, inport, outport);
 161                         if (ret)
 162                                 return ret;
 163                 }
 164         }
 165
 166         csdev->enable = true;
 167
 168         return 0;
 169 }
 170
 171 static void coresight_disable_link(struct coresight_device *csdev)
 172 {
 173         int i, nr_conns;
 174         int link_subtype;
 175         int refport, inport, outport;
 176
 177         inport = coresight_find_link_inport(csdev);
 178         outport = coresight_find_link_outport(csdev);
 179         link_subtype = csdev->subtype.link_subtype;
 180
 181         if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
 182                 refport = inport;
 183                 nr_conns = csdev->nr_inport;
 184         } else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
 185                 refport = outport;
 186                 nr_conns = csdev->nr_outport;
 187         } else {
 188                 refport = 0;
 189                 nr_conns = 1;
 190         }
 191
 192         if (atomic_dec_return(&csdev->refcnt[refport]) == 0) {
 193                 if (link_ops(csdev)->disable)
 194                         link_ops(csdev)->disable(csdev, inport, outport);
 195         }
 196
 197         for (i = 0; i < nr_conns; i++)
 198                 if (atomic_read(&csdev->refcnt[i]) != 0)
 199                         return;
 200
 201         csdev->enable = false;
 202 }
 203
 204 static int coresight_enable_source(struct coresight_device *csdev)
 205 {
 206         int ret;
 207
 208         if (!coresight_source_is_unique(csdev)) {
 209                 dev_warn(&csdev->dev, "traceID %d not unique\n",
 210                          source_ops(csdev)->trace_id(csdev));
 211                 return -EINVAL;
 212         }
 213
 214         if (!csdev->enable) {
 215                 if (source_ops(csdev)->enable) {
 216                         ret = source_ops(csdev)->enable(csdev);
 217                         if (ret)
 218                                 return ret;
 219                 }
 220                 csdev->enable = true;
 221         }
 222
 223         atomic_inc(csdev->refcnt);
 224
 225         return 0;
 226 }
 227
 228 static void coresight_disable_source(struct coresight_device *csdev)
 229 {
 230         if (atomic_dec_return(csdev->refcnt) == 0) {
 231                 if (source_ops(csdev)->disable) {
 232                         source_ops(csdev)->disable(csdev);
 233                         csdev->enable = false;
 234                 }
 235         }
 236 }
 237
 238 static int coresight_enable_path(struct list_head *path)
 239 {
 240         int ret = 0;
 241         struct coresight_device *cd;
 242
 243         list_for_each_entry(cd, path, path_link) {
 244                 if (cd == list_first_entry(path, struct coresight_device,
 245                                            path_link)) {
 246                         ret = coresight_enable_sink(cd);
 247                 } else if (list_is_last(&cd->path_link, path)) {
 248                         /*
 249                          * Don't enable the source just yet - this needs to
 250                          * happen at the very end when all links and sink
 251                          * along the path have been configured properly.
 252                          */
 253                         ;
 254                 } else {
 255                         ret = coresight_enable_link(cd);
 256                 }
 257                 if (ret)
 258                         goto err;
 259         }
 260
 261         return 0;
 262 err:
 263         list_for_each_entry_continue_reverse(cd, path, path_link) {
 264                 if (cd == list_first_entry(path, struct coresight_device,
 265                                            path_link)) {
 266                         coresight_disable_sink(cd);
 267                 } else if (list_is_last(&cd->path_link, path)) {
 268                         ;
 269                 } else {
 270                         coresight_disable_link(cd);
 271                 }
 272         }
 273
 274         return ret;
 275 }
 276
 277 static int coresight_disable_path(struct list_head *path)
 278 {
 279         struct coresight_device *cd;
 280
 281         list_for_each_entry_reverse(cd, path, path_link) {
 282                 if (cd == list_first_entry(path, struct coresight_device,
 283                                            path_link)) {
 284                         coresight_disable_sink(cd);
 285                 } else if (list_is_last(&cd->path_link, path)) {
 286                         /*
 287                          * The source has already been stopped, no need
 288                          * to do it again here.
 289                          */
 290                         ;
 291                 } else {
 292                         coresight_disable_link(cd);
 293                 }
 294         }
 295
 296         return 0;
 297 }
 298
 299 static int coresight_build_paths(struct coresight_device *csdev,
 300                                  struct list_head *path,
 301                                  bool enable)
 302 {
 303         int i, ret = -EINVAL;
 304         struct coresight_connection *conn;
 305
 306         list_add(&csdev->path_link, path);
 307
 308         if (csdev->type == CORESIGHT_DEV_TYPE_SINK && csdev->activated) {
 309                 if (enable)
 310                         ret = coresight_enable_path(path);
 311                 else
 312                         ret = coresight_disable_path(path);
 313         } else {
 314                 for (i = 0; i < csdev->nr_outport; i++) {
 315                         conn = &csdev->conns[i];
 316                         if (coresight_build_paths(conn->child_dev,
 317                                                     path, enable) == 0)
 318                                 ret = 0;
 319                 }
 320         }
 321
 322         if (list_first_entry(path, struct coresight_device, path_link) != csdev)
 323                 dev_err(&csdev->dev, "wrong device in %s\n", __func__);
 324
 325         list_del(&csdev->path_link);
 326
 327         return ret;
 328 }
 329
 330 int coresight_enable(struct coresight_device *csdev)
 331 {
 332         int ret = 0;
 333         LIST_HEAD(path);
 334
 335         mutex_lock(&coresight_mutex);
 336         if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) {
 337                 ret = -EINVAL;
 338                 dev_err(&csdev->dev, "wrong device type in %s\n", __func__);
 339                 goto out;
 340         }
 341         if (csdev->enable)
 342                 goto out;
 343
 344         if (coresight_build_paths(csdev, &path, true)) {
 345                 dev_err(&csdev->dev, "building path(s) failed\n");
 346                 goto out;
 347         }
 348
 349         if (coresight_enable_source(csdev))
 350                 dev_err(&csdev->dev, "source enable failed\n");
 351 out:
 352         mutex_unlock(&coresight_mutex);
 353         return ret;
 354 }
 355 EXPORT_SYMBOL_GPL(coresight_enable);
 356
 357 void coresight_disable(struct coresight_device *csdev)
 358 {
 359         LIST_HEAD(path);
 360
 361         mutex_lock(&coresight_mutex);
 362         if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) {
 363                 dev_err(&csdev->dev, "wrong device type in %s\n", __func__);
 364                 goto out;
 365         }
 366         if (!csdev->enable)
 367                 goto out;
 368
 369         coresight_disable_source(csdev);
 370         if (coresight_build_paths(csdev, &path, false))
 371                 dev_err(&csdev->dev, "releasing path(s) failed\n");
 372
 373 out:
 374         mutex_unlock(&coresight_mutex);
 375 }
 376 EXPORT_SYMBOL_GPL(coresight_disable);
 377
 378 static ssize_t enable_sink_show(struct device *dev,
 379                                 struct device_attribute *attr, char *buf)
 380 {
 381         struct coresight_device *csdev = to_coresight_device(dev);
 382
 383         return scnprintf(buf, PAGE_SIZE, "%u\n", (unsigned)csdev->activated);
 384 }
 385
 386 static ssize_t enable_sink_store(struct device *dev,
 387                                  struct device_attribute *attr,
 388                                  const char *buf, size_t size)
 389 {
 390         int ret;
 391         unsigned long val;
 392         struct coresight_device *csdev = to_coresight_device(dev);
 393
 394         ret = kstrtoul(buf, 10, &val);
 395         if (ret)
 396                 return ret;
 397
 398         if (val)
 399                 csdev->activated = true;
 400         else
 401                 csdev->activated = false;
 402
 403         return size;
 404
 405 }
 406 static DEVICE_ATTR_RW(enable_sink);
 407
 408 static ssize_t enable_source_show(struct device *dev,
 409                                   struct device_attribute *attr, char *buf)
 410 {
 411         struct coresight_device *csdev = to_coresight_device(dev);
 412
 413         return scnprintf(buf, PAGE_SIZE, "%u\n", (unsigned)csdev->enable);
 414 }
 415
 416 static ssize_t enable_source_store(struct device *dev,
 417                                    struct device_attribute *attr,
 418                                    const char *buf, size_t size)
 419 {
 420         int ret = 0;
 421         unsigned long val;
 422         struct coresight_device *csdev = to_coresight_device(dev);
 423
 424         ret = kstrtoul(buf, 10, &val);
 425         if (ret)
 426                 return ret;
 427
 428         if (val) {
 429                 ret = coresight_enable(csdev);
 430                 if (ret)
 431                         return ret;
 432         } else {
 433                 coresight_disable(csdev);
 434         }
 435
 436         return size;
 437 }
 438 static DEVICE_ATTR_RW(enable_source);
 439
 440 static struct attribute *coresight_sink_attrs[] = {
 441         &dev_attr_enable_sink.attr,
 442         NULL,
 443 };
 444 ATTRIBUTE_GROUPS(coresight_sink);
 445
 446 static struct attribute *coresight_source_attrs[] = {
 447         &dev_attr_enable_source.attr,
 448         NULL,
 449 };
 450 ATTRIBUTE_GROUPS(coresight_source);
 451
 452 static struct device_type coresight_dev_type[] = {
 453         {
 454                 .name = "none",
 455         },
 456         {
 457                 .name = "sink",
 458                 .groups = coresight_sink_groups,
 459         },
 460         {
 461                 .name = "link",
 462         },
 463         {
 464                 .name = "linksink",
 465                 .groups = coresight_sink_groups,
 466         },
 467         {
 468                 .name = "source",
 469                 .groups = coresight_source_groups,
 470         },
 471 };
 472
 473 static void coresight_device_release(struct device *dev)
 474 {
 475         struct coresight_device *csdev = to_coresight_device(dev);
 476
 477         kfree(csdev);
 478 }
 479
 480 static int coresight_orphan_match(struct device *dev, void *data)
 481 {
 482         int i;
 483         bool still_orphan = false;
 484         struct coresight_device *csdev, *i_csdev;
 485         struct coresight_connection *conn;
 486
 487         csdev = data;
 488         i_csdev = to_coresight_device(dev);
 489
 490         /* No need to check oneself */
 491         if (csdev == i_csdev)
 492                 return 0;
 493
 494         /* Move on to another component if no connection is orphan */
 495         if (!i_csdev->orphan)
 496                 return 0;
 497         /*
 498          * Circle throuch all the connection of that component.  If we find
 499          * an orphan connection whose name matches @csdev, link it.
 500          */
 501         for (i = 0; i < i_csdev->nr_outport; i++) {
 502                 conn = &i_csdev->conns[i];
 503
 504                 /* We have found at least one orphan connection */
 505                 if (conn->child_dev == NULL) {
 506                         /* Does it match this newly added device? */
 507                         if (!strcmp(dev_name(&csdev->dev), conn->child_name)) {
 508                                 conn->child_dev = csdev;
 509                         } else {
 510                                 /* This component still has an orphan */
 511                                 still_orphan = true;
 512                         }
 513                 }
 514         }
 515
 516         i_csdev->orphan = still_orphan;
 517
 518         /*
 519          * Returning '0' ensures that all known component on the
 520          * bus will be checked.
 521          */
 522         return 0;
 523 }
 524
 525 static void coresight_fixup_orphan_conns(struct coresight_device *csdev)
 526 {
 527         /*
 528          * No need to check for a return value as orphan connection(s)
 529          * are hooked-up with each newly added component.
 530          */
 531         bus_for_each_dev(&coresight_bustype, NULL,
 532                                  csdev, coresight_orphan_match);
 533 }
 534
 535
 536 static int coresight_name_match(struct device *dev, void *data)
 537 {
 538         char *to_match;
 539         struct coresight_device *i_csdev;
 540
 541         to_match = data;
 542         i_csdev = to_coresight_device(dev);
 543
 544         if (!strcmp(to_match, dev_name(&i_csdev->dev)))
 545                 return 1;
 546
 547         return 0;
 548 }
 549
 550 static void coresight_fixup_device_conns(struct coresight_device *csdev)
 551 {
 552         int i;
 553         struct device *dev = NULL;
 554         struct coresight_connection *conn;
 555
 556         for (i = 0; i < csdev->nr_outport; i++) {
 557                 conn = &csdev->conns[i];
 558                 dev = bus_find_device(&coresight_bustype, NULL,
 559                                       (void *)conn->child_name,
 560                                       coresight_name_match);
 561
 562                 if (dev) {
 563                         conn->child_dev = to_coresight_device(dev);
 564                 } else {
 565                         csdev->orphan = true;
 566                         conn->child_dev = NULL;
 567                 }
 568         }
 569 }
 570
 571 /**
 572  * coresight_timeout - loop until a bit has changed to a specific state.
 573  * @addr: base address of the area of interest.
 574  * @offset: address of a register, starting from @addr.
 575  * @position: the position of the bit of interest.
 576  * @value: the value the bit should have.
 577  *
 578  * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
 579  * TIMEOUT_US has elapsed, which ever happens first.
 580  */
 581
 582 int coresight_timeout(void __iomem *addr, u32 offset, int position, int value)
 583 {
 584         int i;
 585         u32 val;
 586
 587         for (i = TIMEOUT_US; i > 0; i--) {
 588                 val = __raw_readl(addr + offset);
 589                 /* waiting on the bit to go from 0 to 1 */
 590                 if (value) {
 591                         if (val & BIT(position))
 592                                 return 0;
 593                 /* waiting on the bit to go from 1 to 0 */
 594                 } else {
 595                         if (!(val & BIT(position)))
 596                                 return 0;
 597                 }
 598
 599                 /*
 600                  * Delay is arbitrary - the specification doesn't say how long
 601                  * we are expected to wait.  Extra check required to make sure
 602                  * we don't wait needlessly on the last iteration.
 603                  */
 604                 if (i - 1)
 605                         udelay(1);
 606         }
 607
 608         return -EAGAIN;
 609 }
 610
 611 struct bus_type coresight_bustype = {
 612         .name   = "coresight",
 613 };
 614
 615 static int __init coresight_init(void)
 616 {
 617         return bus_register(&coresight_bustype);
 618 }
 619 postcore_initcall(coresight_init);
 620
 621 struct coresight_device *coresight_register(struct coresight_desc *desc)
 622 {
 623         int i;
 624         int ret;
 625         int link_subtype;
 626         int nr_refcnts = 1;
 627         atomic_t *refcnts = NULL;
 628         struct coresight_device *csdev;
 629         struct coresight_connection *conns;
 630
 631         csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
 632         if (!csdev) {
 633                 ret = -ENOMEM;
 634                 goto err_kzalloc_csdev;
 635         }
 636
 637         if (desc->type == CORESIGHT_DEV_TYPE_LINK ||
 638             desc->type == CORESIGHT_DEV_TYPE_LINKSINK) {
 639                 link_subtype = desc->subtype.link_subtype;
 640
 641                 if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
 642                         nr_refcnts = desc->pdata->nr_inport;
 643                 else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
 644                         nr_refcnts = desc->pdata->nr_outport;
 645         }
 646
 647         refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
 648         if (!refcnts) {
 649                 ret = -ENOMEM;
 650                 goto err_kzalloc_refcnts;
 651         }
 652
 653         csdev->refcnt = refcnts;
 654
 655         csdev->nr_inport = desc->pdata->nr_inport;
 656         csdev->nr_outport = desc->pdata->nr_outport;
 657         conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
 658         if (!conns) {
 659                 ret = -ENOMEM;
 660                 goto err_kzalloc_conns;
 661         }
 662
 663         for (i = 0; i < csdev->nr_outport; i++) {
 664                 conns[i].outport = desc->pdata->outports[i];
 665                 conns[i].child_name = desc->pdata->child_names[i];
 666                 conns[i].child_port = desc->pdata->child_ports[i];
 667         }
 668
 669         csdev->conns = conns;
 670
 671         csdev->type = desc->type;
 672         csdev->subtype = desc->subtype;
 673         csdev->ops = desc->ops;
 674         csdev->orphan = false;
 675
 676         csdev->dev.type = &coresight_dev_type[desc->type];
 677         csdev->dev.groups = desc->groups;
 678         csdev->dev.parent = desc->dev;
 679         csdev->dev.release = coresight_device_release;
 680         csdev->dev.bus = &coresight_bustype;
 681         dev_set_name(&csdev->dev, "%s", desc->pdata->name);
 682
 683         ret = device_register(&csdev->dev);
 684         if (ret)
 685                 goto err_device_register;
 686
 687         mutex_lock(&coresight_mutex);
 688
 689         coresight_fixup_device_conns(csdev);
 690         coresight_fixup_orphan_conns(csdev);
 691
 692         mutex_unlock(&coresight_mutex);
 693
 694         return csdev;
 695
 696 err_device_register:
 697         kfree(conns);
 698 err_kzalloc_conns:
 699         kfree(refcnts);
 700 err_kzalloc_refcnts:
 701         kfree(csdev);
 702 err_kzalloc_csdev:
 703         return ERR_PTR(ret);
 704 }
 705 EXPORT_SYMBOL_GPL(coresight_register);
 706
 707 void coresight_unregister(struct coresight_device *csdev)
 708 {
 709         mutex_lock(&coresight_mutex);
 710
 711         kfree(csdev->conns);
 712         device_unregister(&csdev->dev);
 713
 714         mutex_unlock(&coresight_mutex);
 715 }
 716 EXPORT_SYMBOL_GPL(coresight_unregister);
 717
 718 MODULE_LICENSE("GPL v2");