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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
30static 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 */
37struct 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 */
46static 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 */
54static struct list_head *stm_path;
55
56/*
57 * When losing synchronisation a new barrier packet needs to be inserted at the
58 * beginning of the data collected in a buffer. That way the decoder knows that
59 * it needs to look for another sync sequence.
60 */
61const u32 barrier_pkt[5] = {0x7fffffff, 0x7fffffff,
62 0x7fffffff, 0x7fffffff, 0x0};
63
64static int coresight_id_match(struct device *dev, void *data)
65{
66 int trace_id, i_trace_id;
67 struct coresight_device *csdev, *i_csdev;
68
69 csdev = data;
70 i_csdev = to_coresight_device(dev);
71
72 /*
73 * No need to care about oneself and components that are not
74 * sources or not enabled
75 */
76 if (i_csdev == csdev || !i_csdev->enable ||
77 i_csdev->type != CORESIGHT_DEV_TYPE_SOURCE)
78 return 0;
79
80 /* Get the source ID for both compoment */
81 trace_id = source_ops(csdev)->trace_id(csdev);
82 i_trace_id = source_ops(i_csdev)->trace_id(i_csdev);
83
84 /* All you need is one */
85 if (trace_id == i_trace_id)
86 return 1;
87
88 return 0;
89}
90
91static int coresight_source_is_unique(struct coresight_device *csdev)
92{
93 int trace_id = source_ops(csdev)->trace_id(csdev);
94
95 /* this shouldn't happen */
96 if (trace_id < 0)
97 return 0;
98
99 return !bus_for_each_dev(&coresight_bustype, NULL,
100 csdev, coresight_id_match);
101}
102
103static int coresight_find_link_inport(struct coresight_device *csdev,
104 struct coresight_device *parent)
105{
106 int i;
107 struct coresight_connection *conn;
108
109 for (i = 0; i < parent->nr_outport; i++) {
110 conn = &parent->conns[i];
111 if (conn->child_dev == csdev)
112 return conn->child_port;
113 }
114
115 dev_err(&csdev->dev, "couldn't find inport, parent: %s, child: %s\n",
116 dev_name(&parent->dev), dev_name(&csdev->dev));
117
118 return 0;
119}
120
121static int coresight_find_link_outport(struct coresight_device *csdev,
122 struct coresight_device *child)
123{
124 int i;
125 struct coresight_connection *conn;
126
127 for (i = 0; i < csdev->nr_outport; i++) {
128 conn = &csdev->conns[i];
129 if (conn->child_dev == child)
130 return conn->outport;
131 }
132
133 dev_err(&csdev->dev, "couldn't find outport, parent: %s, child: %s\n",
134 dev_name(&csdev->dev), dev_name(&child->dev));
135
136 return 0;
137}
138
139static int coresight_enable_sink(struct coresight_device *csdev, u32 mode)
140{
141 int ret;
142
143 if (!csdev->enable) {
144 if (sink_ops(csdev)->enable) {
145 ret = sink_ops(csdev)->enable(csdev, mode);
146 if (ret)
147 return ret;
148 }
149 csdev->enable = true;
150 }
151
152 atomic_inc(csdev->refcnt);
153
154 return 0;
155}
156
157static void coresight_disable_sink(struct coresight_device *csdev)
158{
159 if (atomic_dec_return(csdev->refcnt) == 0) {
160 if (sink_ops(csdev)->disable) {
161 sink_ops(csdev)->disable(csdev);
162 csdev->enable = false;
163 }
164 }
165}
166
167static int coresight_enable_link(struct coresight_device *csdev,
168 struct coresight_device *parent,
169 struct coresight_device *child)
170{
171 int ret;
172 int link_subtype;
173 int refport, inport, outport;
174
175 if (!parent || !child)
176 return -EINVAL;
177
178 inport = coresight_find_link_inport(csdev, parent);
179 outport = coresight_find_link_outport(csdev, child);
180 link_subtype = csdev->subtype.link_subtype;
181
182 if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
183 refport = inport;
184 else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
185 refport = outport;
186 else
187 refport = 0;
188
189 if (atomic_inc_return(&csdev->refcnt[refport]) == 1) {
190 if (link_ops(csdev)->enable) {
191 ret = link_ops(csdev)->enable(csdev, inport, outport);
192 if (ret)
193 return ret;
194 }
195 }
196
197 csdev->enable = true;
198
199 return 0;
200}
201
202static void coresight_disable_link(struct coresight_device *csdev,
203 struct coresight_device *parent,
204 struct coresight_device *child)
205{
206 int i, nr_conns;
207 int link_subtype;
208 int refport, inport, outport;
209
210 if (!parent || !child)
211 return;
212
213 inport = coresight_find_link_inport(csdev, parent);
214 outport = coresight_find_link_outport(csdev, child);
215 link_subtype = csdev->subtype.link_subtype;
216
217 if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
218 refport = inport;
219 nr_conns = csdev->nr_inport;
220 } else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
221 refport = outport;
222 nr_conns = csdev->nr_outport;
223 } else {
224 refport = 0;
225 nr_conns = 1;
226 }
227
228 if (atomic_dec_return(&csdev->refcnt[refport]) == 0) {
229 if (link_ops(csdev)->disable)
230 link_ops(csdev)->disable(csdev, inport, outport);
231 }
232
233 for (i = 0; i < nr_conns; i++)
234 if (atomic_read(&csdev->refcnt[i]) != 0)
235 return;
236
237 csdev->enable = false;
238}
239
240static int coresight_enable_source(struct coresight_device *csdev, u32 mode)
241{
242 int ret;
243
244 if (!coresight_source_is_unique(csdev)) {
245 dev_warn(&csdev->dev, "traceID %d not unique\n",
246 source_ops(csdev)->trace_id(csdev));
247 return -EINVAL;
248 }
249
250 if (!csdev->enable) {
251 if (source_ops(csdev)->enable) {
252 ret = source_ops(csdev)->enable(csdev, NULL, mode);
253 if (ret)
254 return ret;
255 }
256 csdev->enable = true;
257 }
258
259 atomic_inc(csdev->refcnt);
260
261 return 0;
262}
263
264/**
265 * coresight_disable_source - Drop the reference count by 1 and disable
266 * the device if there are no users left.
267 *
268 * @csdev - The coresight device to disable
269 *
270 * Returns true if the device has been disabled.
271 */
272static bool coresight_disable_source(struct coresight_device *csdev)
273{
274 if (atomic_dec_return(csdev->refcnt) == 0) {
275 if (source_ops(csdev)->disable)
276 source_ops(csdev)->disable(csdev, NULL);
277 csdev->enable = false;
278 }
279 return !csdev->enable;
280}
281
282void coresight_disable_path(struct list_head *path)
283{
284 u32 type;
285 struct coresight_node *nd;
286 struct coresight_device *csdev, *parent, *child;
287
288 list_for_each_entry(nd, path, link) {
289 csdev = nd->csdev;
290 type = csdev->type;
291
292 /*
293 * ETF devices are tricky... They can be a link or a sink,
294 * depending on how they are configured. If an ETF has been
295 * "activated" it will be configured as a sink, otherwise
296 * go ahead with the link configuration.
297 */
298 if (type == CORESIGHT_DEV_TYPE_LINKSINK)
299 type = (csdev == coresight_get_sink(path)) ?
300 CORESIGHT_DEV_TYPE_SINK :
301 CORESIGHT_DEV_TYPE_LINK;
302
303 switch (type) {
304 case CORESIGHT_DEV_TYPE_SINK:
305 coresight_disable_sink(csdev);
306 break;
307 case CORESIGHT_DEV_TYPE_SOURCE:
308 /* sources are disabled from either sysFS or Perf */
309 break;
310 case CORESIGHT_DEV_TYPE_LINK:
311 parent = list_prev_entry(nd, link)->csdev;
312 child = list_next_entry(nd, link)->csdev;
313 coresight_disable_link(csdev, parent, child);
314 break;
315 default:
316 break;
317 }
318 }
319}
320
321int coresight_enable_path(struct list_head *path, u32 mode)
322{
323
324 int ret = 0;
325 u32 type;
326 struct coresight_node *nd;
327 struct coresight_device *csdev, *parent, *child;
328
329 list_for_each_entry_reverse(nd, path, link) {
330 csdev = nd->csdev;
331 type = csdev->type;
332
333 /*
334 * ETF devices are tricky... They can be a link or a sink,
335 * depending on how they are configured. If an ETF has been
336 * "activated" it will be configured as a sink, otherwise
337 * go ahead with the link configuration.
338 */
339 if (type == CORESIGHT_DEV_TYPE_LINKSINK)
340 type = (csdev == coresight_get_sink(path)) ?
341 CORESIGHT_DEV_TYPE_SINK :
342 CORESIGHT_DEV_TYPE_LINK;
343
344 switch (type) {
345 case CORESIGHT_DEV_TYPE_SINK:
346 ret = coresight_enable_sink(csdev, mode);
347 if (ret)
348 goto err;
349 break;
350 case CORESIGHT_DEV_TYPE_SOURCE:
351 /* sources are enabled from either sysFS or Perf */
352 break;
353 case CORESIGHT_DEV_TYPE_LINK:
354 parent = list_prev_entry(nd, link)->csdev;
355 child = list_next_entry(nd, link)->csdev;
356 ret = coresight_enable_link(csdev, parent, child);
357 if (ret)
358 goto err;
359 break;
360 default:
361 goto err;
362 }
363 }
364
365out:
366 return ret;
367err:
368 coresight_disable_path(path);
369 goto out;
370}
371
372struct coresight_device *coresight_get_sink(struct list_head *path)
373{
374 struct coresight_device *csdev;
375
376 if (!path)
377 return NULL;
378
379 csdev = list_last_entry(path, struct coresight_node, link)->csdev;
380 if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
381 csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
382 return NULL;
383
384 return csdev;
385}
386
387static int coresight_enabled_sink(struct device *dev, void *data)
388{
389 bool *reset = data;
390 struct coresight_device *csdev = to_coresight_device(dev);
391
392 if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
393 csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
394 csdev->activated) {
395 /*
396 * Now that we have a handle on the sink for this session,
397 * disable the sysFS "enable_sink" flag so that possible
398 * concurrent perf session that wish to use another sink don't
399 * trip on it. Doing so has no ramification for the current
400 * session.
401 */
402 if (*reset)
403 csdev->activated = false;
404
405 return 1;
406 }
407
408 return 0;
409}
410
411/**
412 * coresight_get_enabled_sink - returns the first enabled sink found on the bus
413 * @deactivate: Whether the 'enable_sink' flag should be reset
414 *
415 * When operated from perf the deactivate parameter should be set to 'true'.
416 * That way the "enabled_sink" flag of the sink that was selected can be reset,
417 * allowing for other concurrent perf sessions to choose a different sink.
418 *
419 * When operated from sysFS users have full control and as such the deactivate
420 * parameter should be set to 'false', hence mandating users to explicitly
421 * clear the flag.
422 */
423struct coresight_device *coresight_get_enabled_sink(bool deactivate)
424{
425 struct device *dev = NULL;
426
427 dev = bus_find_device(&coresight_bustype, NULL, &deactivate,
428 coresight_enabled_sink);
429
430 return dev ? to_coresight_device(dev) : NULL;
431}
432
433/**
434 * _coresight_build_path - recursively build a path from a @csdev to a sink.
435 * @csdev: The device to start from.
436 * @path: The list to add devices to.
437 *
438 * The tree of Coresight device is traversed until an activated sink is
439 * found. From there the sink is added to the list along with all the
440 * devices that led to that point - the end result is a list from source
441 * to sink. In that list the source is the first device and the sink the
442 * last one.
443 */
444static int _coresight_build_path(struct coresight_device *csdev,
445 struct coresight_device *sink,
446 struct list_head *path)
447{
448 int i;
449 bool found = false;
450 struct coresight_node *node;
451
452 /* An activated sink has been found. Enqueue the element */
453 if (csdev == sink)
454 goto out;
455
456 /* Not a sink - recursively explore each port found on this element */
457 for (i = 0; i < csdev->nr_outport; i++) {
458 struct coresight_device *child_dev = csdev->conns[i].child_dev;
459
460 if (child_dev &&
461 _coresight_build_path(child_dev, sink, path) == 0) {
462 found = true;
463 break;
464 }
465 }
466
467 if (!found)
468 return -ENODEV;
469
470out:
471 /*
472 * A path from this element to a sink has been found. The elements
473 * leading to the sink are already enqueued, all that is left to do
474 * is tell the PM runtime core we need this element and add a node
475 * for it.
476 */
477 node = kzalloc(sizeof(struct coresight_node), GFP_KERNEL);
478 if (!node)
479 return -ENOMEM;
480
481 node->csdev = csdev;
482 list_add(&node->link, path);
483 pm_runtime_get_sync(csdev->dev.parent);
484
485 return 0;
486}
487
488struct list_head *coresight_build_path(struct coresight_device *source,
489 struct coresight_device *sink)
490{
491 struct list_head *path;
492 int rc;
493
494 if (!sink)
495 return ERR_PTR(-EINVAL);
496
497 path = kzalloc(sizeof(struct list_head), GFP_KERNEL);
498 if (!path)
499 return ERR_PTR(-ENOMEM);
500
501 INIT_LIST_HEAD(path);
502
503 rc = _coresight_build_path(source, sink, path);
504 if (rc) {
505 kfree(path);
506 return ERR_PTR(rc);
507 }
508
509 return path;
510}
511
512/**
513 * coresight_release_path - release a previously built path.
514 * @path: the path to release.
515 *
516 * Go through all the elements of a path and 1) removed it from the list and
517 * 2) free the memory allocated for each node.
518 */
519void coresight_release_path(struct list_head *path)
520{
521 struct coresight_device *csdev;
522 struct coresight_node *nd, *next;
523
524 list_for_each_entry_safe(nd, next, path, link) {
525 csdev = nd->csdev;
526
527 pm_runtime_put_sync(csdev->dev.parent);
528 list_del(&nd->link);
529 kfree(nd);
530 }
531
532 kfree(path);
533 path = NULL;
534}
535
536/** coresight_validate_source - make sure a source has the right credentials
537 * @csdev: the device structure for a source.
538 * @function: the function this was called from.
539 *
540 * Assumes the coresight_mutex is held.
541 */
542static int coresight_validate_source(struct coresight_device *csdev,
543 const char *function)
544{
545 u32 type, subtype;
546
547 type = csdev->type;
548 subtype = csdev->subtype.source_subtype;
549
550 if (type != CORESIGHT_DEV_TYPE_SOURCE) {
551 dev_err(&csdev->dev, "wrong device type in %s\n", function);
552 return -EINVAL;
553 }
554
555 if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC &&
556 subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE) {
557 dev_err(&csdev->dev, "wrong device subtype in %s\n", function);
558 return -EINVAL;
559 }
560
561 return 0;
562}
563
564int coresight_enable(struct coresight_device *csdev)
565{
566 int cpu, ret = 0;
567 struct coresight_device *sink;
568 struct list_head *path;
569 enum coresight_dev_subtype_source subtype;
570
571 subtype = csdev->subtype.source_subtype;
572
573 mutex_lock(&coresight_mutex);
574
575 ret = coresight_validate_source(csdev, __func__);
576 if (ret)
577 goto out;
578
579 if (csdev->enable) {
580 /*
581 * There could be multiple applications driving the software
582 * source. So keep the refcount for each such user when the
583 * source is already enabled.
584 */
585 if (subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE)
586 atomic_inc(csdev->refcnt);
587 goto out;
588 }
589
590 /*
591 * Search for a valid sink for this session but don't reset the
592 * "enable_sink" flag in sysFS. Users get to do that explicitly.
593 */
594 sink = coresight_get_enabled_sink(false);
595 if (!sink) {
596 ret = -EINVAL;
597 goto out;
598 }
599
600 path = coresight_build_path(csdev, sink);
601 if (IS_ERR(path)) {
602 pr_err("building path(s) failed\n");
603 ret = PTR_ERR(path);
604 goto out;
605 }
606
607 ret = coresight_enable_path(path, CS_MODE_SYSFS);
608 if (ret)
609 goto err_path;
610
611 ret = coresight_enable_source(csdev, CS_MODE_SYSFS);
612 if (ret)
613 goto err_source;
614
615 switch (subtype) {
616 case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
617 /*
618 * When working from sysFS it is important to keep track
619 * of the paths that were created so that they can be
620 * undone in 'coresight_disable()'. Since there can only
621 * be a single session per tracer (when working from sysFS)
622 * a per-cpu variable will do just fine.
623 */
624 cpu = source_ops(csdev)->cpu_id(csdev);
625 per_cpu(tracer_path, cpu) = path;
626 break;
627 case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
628 stm_path = path;
629 break;
630 default:
631 /* We can't be here */
632 break;
633 }
634
635out:
636 mutex_unlock(&coresight_mutex);
637 return ret;
638
639err_source:
640 coresight_disable_path(path);
641
642err_path:
643 coresight_release_path(path);
644 goto out;
645}
646EXPORT_SYMBOL_GPL(coresight_enable);
647
648void coresight_disable(struct coresight_device *csdev)
649{
650 int cpu, ret;
651 struct list_head *path = NULL;
652
653 mutex_lock(&coresight_mutex);
654
655 ret = coresight_validate_source(csdev, __func__);
656 if (ret)
657 goto out;
658
659 if (!csdev->enable || !coresight_disable_source(csdev))
660 goto out;
661
662 switch (csdev->subtype.source_subtype) {
663 case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
664 cpu = source_ops(csdev)->cpu_id(csdev);
665 path = per_cpu(tracer_path, cpu);
666 per_cpu(tracer_path, cpu) = NULL;
667 break;
668 case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
669 path = stm_path;
670 stm_path = NULL;
671 break;
672 default:
673 /* We can't be here */
674 break;
675 }
676
677 coresight_disable_path(path);
678 coresight_release_path(path);
679
680out:
681 mutex_unlock(&coresight_mutex);
682}
683EXPORT_SYMBOL_GPL(coresight_disable);
684
685static ssize_t enable_sink_show(struct device *dev,
686 struct device_attribute *attr, char *buf)
687{
688 struct coresight_device *csdev = to_coresight_device(dev);
689
690 return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->activated);
691}
692
693static ssize_t enable_sink_store(struct device *dev,
694 struct device_attribute *attr,
695 const char *buf, size_t size)
696{
697 int ret;
698 unsigned long val;
699 struct coresight_device *csdev = to_coresight_device(dev);
700
701 ret = kstrtoul(buf, 10, &val);
702 if (ret)
703 return ret;
704
705 if (val)
706 csdev->activated = true;
707 else
708 csdev->activated = false;
709
710 return size;
711
712}
713static DEVICE_ATTR_RW(enable_sink);
714
715static ssize_t enable_source_show(struct device *dev,
716 struct device_attribute *attr, char *buf)
717{
718 struct coresight_device *csdev = to_coresight_device(dev);
719
720 return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->enable);
721}
722
723static ssize_t enable_source_store(struct device *dev,
724 struct device_attribute *attr,
725 const char *buf, size_t size)
726{
727 int ret = 0;
728 unsigned long val;
729 struct coresight_device *csdev = to_coresight_device(dev);
730
731 ret = kstrtoul(buf, 10, &val);
732 if (ret)
733 return ret;
734
735 if (val) {
736 ret = coresight_enable(csdev);
737 if (ret)
738 return ret;
739 } else {
740 coresight_disable(csdev);
741 }
742
743 return size;
744}
745static DEVICE_ATTR_RW(enable_source);
746
747static struct attribute *coresight_sink_attrs[] = {
748 &dev_attr_enable_sink.attr,
749 NULL,
750};
751ATTRIBUTE_GROUPS(coresight_sink);
752
753static struct attribute *coresight_source_attrs[] = {
754 &dev_attr_enable_source.attr,
755 NULL,
756};
757ATTRIBUTE_GROUPS(coresight_source);
758
759static struct device_type coresight_dev_type[] = {
760 {
761 .name = "none",
762 },
763 {
764 .name = "sink",
765 .groups = coresight_sink_groups,
766 },
767 {
768 .name = "link",
769 },
770 {
771 .name = "linksink",
772 .groups = coresight_sink_groups,
773 },
774 {
775 .name = "source",
776 .groups = coresight_source_groups,
777 },
778};
779
780static void coresight_device_release(struct device *dev)
781{
782 struct coresight_device *csdev = to_coresight_device(dev);
783
784 kfree(csdev->conns);
785 kfree(csdev->refcnt);
786 kfree(csdev);
787}
788
789static int coresight_orphan_match(struct device *dev, void *data)
790{
791 int i;
792 bool still_orphan = false;
793 struct coresight_device *csdev, *i_csdev;
794 struct coresight_connection *conn;
795
796 csdev = data;
797 i_csdev = to_coresight_device(dev);
798
799 /* No need to check oneself */
800 if (csdev == i_csdev)
801 return 0;
802
803 /* Move on to another component if no connection is orphan */
804 if (!i_csdev->orphan)
805 return 0;
806 /*
807 * Circle throuch all the connection of that component. If we find
808 * an orphan connection whose name matches @csdev, link it.
809 */
810 for (i = 0; i < i_csdev->nr_outport; i++) {
811 conn = &i_csdev->conns[i];
812
813 /* We have found at least one orphan connection */
814 if (conn->child_dev == NULL) {
815 /* Does it match this newly added device? */
816 if (conn->child_name &&
817 !strcmp(dev_name(&csdev->dev), conn->child_name)) {
818 conn->child_dev = csdev;
819 } else {
820 /* This component still has an orphan */
821 still_orphan = true;
822 }
823 }
824 }
825
826 i_csdev->orphan = still_orphan;
827
828 /*
829 * Returning '0' ensures that all known component on the
830 * bus will be checked.
831 */
832 return 0;
833}
834
835static void coresight_fixup_orphan_conns(struct coresight_device *csdev)
836{
837 /*
838 * No need to check for a return value as orphan connection(s)
839 * are hooked-up with each newly added component.
840 */
841 bus_for_each_dev(&coresight_bustype, NULL,
842 csdev, coresight_orphan_match);
843}
844
845
846static void coresight_fixup_device_conns(struct coresight_device *csdev)
847{
848 int i;
849
850 for (i = 0; i < csdev->nr_outport; i++) {
851 struct coresight_connection *conn = &csdev->conns[i];
852 struct device *dev = NULL;
853
854 if (conn->child_name)
855 dev = bus_find_device_by_name(&coresight_bustype, NULL,
856 conn->child_name);
857 if (dev) {
858 conn->child_dev = to_coresight_device(dev);
859 /* and put reference from 'bus_find_device()' */
860 put_device(dev);
861 } else {
862 csdev->orphan = true;
863 conn->child_dev = NULL;
864 }
865 }
866}
867
868static int coresight_remove_match(struct device *dev, void *data)
869{
870 int i;
871 struct coresight_device *csdev, *iterator;
872 struct coresight_connection *conn;
873
874 csdev = data;
875 iterator = to_coresight_device(dev);
876
877 /* No need to check oneself */
878 if (csdev == iterator)
879 return 0;
880
881 /*
882 * Circle throuch all the connection of that component. If we find
883 * a connection whose name matches @csdev, remove it.
884 */
885 for (i = 0; i < iterator->nr_outport; i++) {
886 conn = &iterator->conns[i];
887
888 if (conn->child_dev == NULL)
889 continue;
890
891 if (!strcmp(dev_name(&csdev->dev), conn->child_name)) {
892 iterator->orphan = true;
893 conn->child_dev = NULL;
894 /* No need to continue */
895 break;
896 }
897 }
898
899 /*
900 * Returning '0' ensures that all known component on the
901 * bus will be checked.
902 */
903 return 0;
904}
905
906static void coresight_remove_conns(struct coresight_device *csdev)
907{
908 bus_for_each_dev(&coresight_bustype, NULL,
909 csdev, coresight_remove_match);
910}
911
912/**
913 * coresight_timeout - loop until a bit has changed to a specific state.
914 * @addr: base address of the area of interest.
915 * @offset: address of a register, starting from @addr.
916 * @position: the position of the bit of interest.
917 * @value: the value the bit should have.
918 *
919 * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
920 * TIMEOUT_US has elapsed, which ever happens first.
921 */
922
923int coresight_timeout(void __iomem *addr, u32 offset, int position, int value)
924{
925 int i;
926 u32 val;
927
928 for (i = TIMEOUT_US; i > 0; i--) {
929 val = __raw_readl(addr + offset);
930 /* waiting on the bit to go from 0 to 1 */
931 if (value) {
932 if (val & BIT(position))
933 return 0;
934 /* waiting on the bit to go from 1 to 0 */
935 } else {
936 if (!(val & BIT(position)))
937 return 0;
938 }
939
940 /*
941 * Delay is arbitrary - the specification doesn't say how long
942 * we are expected to wait. Extra check required to make sure
943 * we don't wait needlessly on the last iteration.
944 */
945 if (i - 1)
946 udelay(1);
947 }
948
949 return -EAGAIN;
950}
951
952struct bus_type coresight_bustype = {
953 .name = "coresight",
954};
955
956static int __init coresight_init(void)
957{
958 return bus_register(&coresight_bustype);
959}
960postcore_initcall(coresight_init);
961
962struct coresight_device *coresight_register(struct coresight_desc *desc)
963{
964 int i;
965 int ret;
966 int link_subtype;
967 int nr_refcnts = 1;
968 atomic_t *refcnts = NULL;
969 struct coresight_device *csdev;
970 struct coresight_connection *conns = NULL;
971
972 csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
973 if (!csdev) {
974 ret = -ENOMEM;
975 goto err_kzalloc_csdev;
976 }
977
978 if (desc->type == CORESIGHT_DEV_TYPE_LINK ||
979 desc->type == CORESIGHT_DEV_TYPE_LINKSINK) {
980 link_subtype = desc->subtype.link_subtype;
981
982 if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
983 nr_refcnts = desc->pdata->nr_inport;
984 else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
985 nr_refcnts = desc->pdata->nr_outport;
986 }
987
988 refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
989 if (!refcnts) {
990 ret = -ENOMEM;
991 goto err_kzalloc_refcnts;
992 }
993
994 csdev->refcnt = refcnts;
995
996 csdev->nr_inport = desc->pdata->nr_inport;
997 csdev->nr_outport = desc->pdata->nr_outport;
998
999 /* Initialise connections if there is at least one outport */
1000 if (csdev->nr_outport) {
1001 conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
1002 if (!conns) {
1003 ret = -ENOMEM;
1004 goto err_kzalloc_conns;
1005 }
1006
1007 for (i = 0; i < csdev->nr_outport; i++) {
1008 conns[i].outport = desc->pdata->outports[i];
1009 conns[i].child_name = desc->pdata->child_names[i];
1010 conns[i].child_port = desc->pdata->child_ports[i];
1011 }
1012 }
1013
1014 csdev->conns = conns;
1015
1016 csdev->type = desc->type;
1017 csdev->subtype = desc->subtype;
1018 csdev->ops = desc->ops;
1019 csdev->orphan = false;
1020
1021 csdev->dev.type = &coresight_dev_type[desc->type];
1022 csdev->dev.groups = desc->groups;
1023 csdev->dev.parent = desc->dev;
1024 csdev->dev.release = coresight_device_release;
1025 csdev->dev.bus = &coresight_bustype;
1026 dev_set_name(&csdev->dev, "%s", desc->pdata->name);
1027
1028 ret = device_register(&csdev->dev);
1029 if (ret)
1030 goto err_device_register;
1031
1032 mutex_lock(&coresight_mutex);
1033
1034 coresight_fixup_device_conns(csdev);
1035 coresight_fixup_orphan_conns(csdev);
1036
1037 mutex_unlock(&coresight_mutex);
1038
1039 return csdev;
1040
1041err_device_register:
1042 kfree(conns);
1043err_kzalloc_conns:
1044 kfree(refcnts);
1045err_kzalloc_refcnts:
1046 kfree(csdev);
1047err_kzalloc_csdev:
1048 return ERR_PTR(ret);
1049}
1050EXPORT_SYMBOL_GPL(coresight_register);
1051
1052void coresight_unregister(struct coresight_device *csdev)
1053{
1054 /* Remove references of that device in the topology */
1055 coresight_remove_conns(csdev);
1056 device_unregister(&csdev->dev);
1057}
1058EXPORT_SYMBOL_GPL(coresight_unregister);