1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2012, The Linux Foundation. All rights reserved.
4  */
5 
6 #include <linux/build_bug.h>
7 #include <linux/kernel.h>
8 #include <linux/init.h>
9 #include <linux/types.h>
10 #include <linux/device.h>
11 #include <linux/io.h>
12 #include <linux/idr.h>
13 #include <linux/err.h>
14 #include <linux/export.h>
15 #include <linux/slab.h>
16 #include <linux/stringhash.h>
17 #include <linux/mutex.h>
18 #include <linux/clk.h>
19 #include <linux/coresight.h>
20 #include <linux/property.h>
21 #include <linux/delay.h>
22 #include <linux/pm_runtime.h>
23 
24 #include "coresight-etm-perf.h"
25 #include "coresight-priv.h"
26 #include "coresight-syscfg.h"
27 
28 static DEFINE_MUTEX(coresight_mutex);
29 static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
30 
31 /*
32  * Use IDR to map the hash of the source's device name
33  * to the pointer of path for the source. The idr is for
34  * the sources which aren't associated with CPU.
35  */
36 static DEFINE_IDR(path_idr);
37 
38 /**
39  * struct coresight_node - elements of a path, from source to sink
40  * @csdev:	Address of an element.
41  * @link:	hook to the list.
42  */
43 struct coresight_node {
44 	struct coresight_device *csdev;
45 	struct list_head link;
46 };
47 
48 /*
49  * When operating Coresight drivers from the sysFS interface, only a single
50  * path can exist from a tracer (associated to a CPU) to a sink.
51  */
52 static DEFINE_PER_CPU(struct list_head *, tracer_path);
53 
54 /*
55  * When losing synchronisation a new barrier packet needs to be inserted at the
56  * beginning of the data collected in a buffer.  That way the decoder knows that
57  * it needs to look for another sync sequence.
58  */
59 const u32 coresight_barrier_pkt[4] = {0x7fffffff, 0x7fffffff, 0x7fffffff, 0x7fffffff};
60 EXPORT_SYMBOL_GPL(coresight_barrier_pkt);
61 
62 static const struct cti_assoc_op *cti_assoc_ops;
63 
64 ssize_t coresight_simple_show_pair(struct device *_dev,
65 			      struct device_attribute *attr, char *buf)
66 {
67 	struct coresight_device *csdev = container_of(_dev, struct coresight_device, dev);
68 	struct cs_pair_attribute *cs_attr = container_of(attr, struct cs_pair_attribute, attr);
69 	u64 val;
70 
71 	pm_runtime_get_sync(_dev->parent);
72 	val = csdev_access_relaxed_read_pair(&csdev->access, cs_attr->lo_off, cs_attr->hi_off);
73 	pm_runtime_put_sync(_dev->parent);
74 	return sysfs_emit(buf, "0x%llx\n", val);
75 }
76 EXPORT_SYMBOL_GPL(coresight_simple_show_pair);
77 
78 ssize_t coresight_simple_show32(struct device *_dev,
79 			      struct device_attribute *attr, char *buf)
80 {
81 	struct coresight_device *csdev = container_of(_dev, struct coresight_device, dev);
82 	struct cs_off_attribute *cs_attr = container_of(attr, struct cs_off_attribute, attr);
83 	u64 val;
84 
85 	pm_runtime_get_sync(_dev->parent);
86 	val = csdev_access_relaxed_read32(&csdev->access, cs_attr->off);
87 	pm_runtime_put_sync(_dev->parent);
88 	return sysfs_emit(buf, "0x%llx\n", val);
89 }
90 EXPORT_SYMBOL_GPL(coresight_simple_show32);
91 
92 void coresight_set_cti_ops(const struct cti_assoc_op *cti_op)
93 {
94 	cti_assoc_ops = cti_op;
95 }
96 EXPORT_SYMBOL_GPL(coresight_set_cti_ops);
97 
98 void coresight_remove_cti_ops(void)
99 {
100 	cti_assoc_ops = NULL;
101 }
102 EXPORT_SYMBOL_GPL(coresight_remove_cti_ops);
103 
104 void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev)
105 {
106 	per_cpu(csdev_sink, cpu) = csdev;
107 }
108 EXPORT_SYMBOL_GPL(coresight_set_percpu_sink);
109 
110 struct coresight_device *coresight_get_percpu_sink(int cpu)
111 {
112 	return per_cpu(csdev_sink, cpu);
113 }
114 EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
115 
116 static struct coresight_connection *
117 coresight_find_out_connection(struct coresight_device *src_dev,
118 			      struct coresight_device *dest_dev)
119 {
120 	int i;
121 	struct coresight_connection *conn;
122 
123 	for (i = 0; i < src_dev->pdata->nr_outconns; i++) {
124 		conn = src_dev->pdata->out_conns[i];
125 		if (conn->dest_dev == dest_dev)
126 			return conn;
127 	}
128 
129 	dev_err(&src_dev->dev,
130 		"couldn't find output connection, src_dev: %s, dest_dev: %s\n",
131 		dev_name(&src_dev->dev), dev_name(&dest_dev->dev));
132 
133 	return ERR_PTR(-ENODEV);
134 }
135 
136 static inline u32 coresight_read_claim_tags(struct coresight_device *csdev)
137 {
138 	return csdev_access_relaxed_read32(&csdev->access, CORESIGHT_CLAIMCLR);
139 }
140 
141 static inline bool coresight_is_claimed_self_hosted(struct coresight_device *csdev)
142 {
143 	return coresight_read_claim_tags(csdev) == CORESIGHT_CLAIM_SELF_HOSTED;
144 }
145 
146 static inline bool coresight_is_claimed_any(struct coresight_device *csdev)
147 {
148 	return coresight_read_claim_tags(csdev) != 0;
149 }
150 
151 static inline void coresight_set_claim_tags(struct coresight_device *csdev)
152 {
153 	csdev_access_relaxed_write32(&csdev->access, CORESIGHT_CLAIM_SELF_HOSTED,
154 				     CORESIGHT_CLAIMSET);
155 	isb();
156 }
157 
158 static inline void coresight_clear_claim_tags(struct coresight_device *csdev)
159 {
160 	csdev_access_relaxed_write32(&csdev->access, CORESIGHT_CLAIM_SELF_HOSTED,
161 				     CORESIGHT_CLAIMCLR);
162 	isb();
163 }
164 
165 /*
166  * coresight_claim_device_unlocked : Claim the device for self-hosted usage
167  * to prevent an external tool from touching this device. As per PSCI
168  * standards, section "Preserving the execution context" => "Debug and Trace
169  * save and Restore", DBGCLAIM[1] is reserved for Self-hosted debug/trace and
170  * DBGCLAIM[0] is reserved for external tools.
171  *
172  * Called with CS_UNLOCKed for the component.
173  * Returns : 0 on success
174  */
175 int coresight_claim_device_unlocked(struct coresight_device *csdev)
176 {
177 	if (WARN_ON(!csdev))
178 		return -EINVAL;
179 
180 	if (coresight_is_claimed_any(csdev))
181 		return -EBUSY;
182 
183 	coresight_set_claim_tags(csdev);
184 	if (coresight_is_claimed_self_hosted(csdev))
185 		return 0;
186 	/* There was a race setting the tags, clean up and fail */
187 	coresight_clear_claim_tags(csdev);
188 	return -EBUSY;
189 }
190 EXPORT_SYMBOL_GPL(coresight_claim_device_unlocked);
191 
192 int coresight_claim_device(struct coresight_device *csdev)
193 {
194 	int rc;
195 
196 	if (WARN_ON(!csdev))
197 		return -EINVAL;
198 
199 	CS_UNLOCK(csdev->access.base);
200 	rc = coresight_claim_device_unlocked(csdev);
201 	CS_LOCK(csdev->access.base);
202 
203 	return rc;
204 }
205 EXPORT_SYMBOL_GPL(coresight_claim_device);
206 
207 /*
208  * coresight_disclaim_device_unlocked : Clear the claim tags for the device.
209  * Called with CS_UNLOCKed for the component.
210  */
211 void coresight_disclaim_device_unlocked(struct coresight_device *csdev)
212 {
213 
214 	if (WARN_ON(!csdev))
215 		return;
216 
217 	if (coresight_is_claimed_self_hosted(csdev))
218 		coresight_clear_claim_tags(csdev);
219 	else
220 		/*
221 		 * The external agent may have not honoured our claim
222 		 * and has manipulated it. Or something else has seriously
223 		 * gone wrong in our driver.
224 		 */
225 		WARN_ON_ONCE(1);
226 }
227 EXPORT_SYMBOL_GPL(coresight_disclaim_device_unlocked);
228 
229 void coresight_disclaim_device(struct coresight_device *csdev)
230 {
231 	if (WARN_ON(!csdev))
232 		return;
233 
234 	CS_UNLOCK(csdev->access.base);
235 	coresight_disclaim_device_unlocked(csdev);
236 	CS_LOCK(csdev->access.base);
237 }
238 EXPORT_SYMBOL_GPL(coresight_disclaim_device);
239 
240 /*
241  * Add a helper as an output device. This function takes the @coresight_mutex
242  * because it's assumed that it's called from the helper device, outside of the
243  * core code where the mutex would already be held. Don't add new calls to this
244  * from inside the core code, instead try to add the new helper to the DT and
245  * ACPI where it will be picked up and linked automatically.
246  */
247 void coresight_add_helper(struct coresight_device *csdev,
248 			  struct coresight_device *helper)
249 {
250 	int i;
251 	struct coresight_connection conn = {};
252 	struct coresight_connection *new_conn;
253 
254 	mutex_lock(&coresight_mutex);
255 	conn.dest_fwnode = fwnode_handle_get(dev_fwnode(&helper->dev));
256 	conn.dest_dev = helper;
257 	conn.dest_port = conn.src_port = -1;
258 	conn.src_dev = csdev;
259 
260 	/*
261 	 * Check for duplicates because this is called every time a helper
262 	 * device is re-loaded. Existing connections will get re-linked
263 	 * automatically.
264 	 */
265 	for (i = 0; i < csdev->pdata->nr_outconns; ++i)
266 		if (csdev->pdata->out_conns[i]->dest_fwnode == conn.dest_fwnode)
267 			goto unlock;
268 
269 	new_conn = coresight_add_out_conn(csdev->dev.parent, csdev->pdata,
270 					  &conn);
271 	if (!IS_ERR(new_conn))
272 		coresight_add_in_conn(new_conn);
273 
274 unlock:
275 	mutex_unlock(&coresight_mutex);
276 }
277 EXPORT_SYMBOL_GPL(coresight_add_helper);
278 
279 static int coresight_enable_sink(struct coresight_device *csdev,
280 				 enum cs_mode mode, void *data)
281 {
282 	int ret;
283 
284 	/*
285 	 * We need to make sure the "new" session is compatible with the
286 	 * existing "mode" of operation.
287 	 */
288 	if (!sink_ops(csdev)->enable)
289 		return -EINVAL;
290 
291 	ret = sink_ops(csdev)->enable(csdev, mode, data);
292 	if (ret)
293 		return ret;
294 
295 	csdev->enable = true;
296 
297 	return 0;
298 }
299 
300 static void coresight_disable_sink(struct coresight_device *csdev)
301 {
302 	int ret;
303 
304 	if (!sink_ops(csdev)->disable)
305 		return;
306 
307 	ret = sink_ops(csdev)->disable(csdev);
308 	if (ret)
309 		return;
310 	csdev->enable = false;
311 }
312 
313 static int coresight_enable_link(struct coresight_device *csdev,
314 				 struct coresight_device *parent,
315 				 struct coresight_device *child)
316 {
317 	int ret = 0;
318 	int link_subtype;
319 	struct coresight_connection *inconn, *outconn;
320 
321 	if (!parent || !child)
322 		return -EINVAL;
323 
324 	inconn = coresight_find_out_connection(parent, csdev);
325 	outconn = coresight_find_out_connection(csdev, child);
326 	link_subtype = csdev->subtype.link_subtype;
327 
328 	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG && IS_ERR(inconn))
329 		return PTR_ERR(inconn);
330 	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT && IS_ERR(outconn))
331 		return PTR_ERR(outconn);
332 
333 	if (link_ops(csdev)->enable) {
334 		ret = link_ops(csdev)->enable(csdev, inconn, outconn);
335 		if (!ret)
336 			csdev->enable = true;
337 	}
338 
339 	return ret;
340 }
341 
342 static void coresight_disable_link(struct coresight_device *csdev,
343 				   struct coresight_device *parent,
344 				   struct coresight_device *child)
345 {
346 	int i;
347 	int link_subtype;
348 	struct coresight_connection *inconn, *outconn;
349 
350 	if (!parent || !child)
351 		return;
352 
353 	inconn = coresight_find_out_connection(parent, csdev);
354 	outconn = coresight_find_out_connection(csdev, child);
355 	link_subtype = csdev->subtype.link_subtype;
356 
357 	if (link_ops(csdev)->disable) {
358 		link_ops(csdev)->disable(csdev, inconn, outconn);
359 	}
360 
361 	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
362 		for (i = 0; i < csdev->pdata->nr_inconns; i++)
363 			if (atomic_read(&csdev->pdata->in_conns[i]->dest_refcnt) !=
364 			    0)
365 				return;
366 	} else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
367 		for (i = 0; i < csdev->pdata->nr_outconns; i++)
368 			if (atomic_read(&csdev->pdata->out_conns[i]->src_refcnt) !=
369 			    0)
370 				return;
371 	} else {
372 		if (atomic_read(&csdev->refcnt) != 0)
373 			return;
374 	}
375 
376 	csdev->enable = false;
377 }
378 
379 int coresight_enable_source(struct coresight_device *csdev, enum cs_mode mode,
380 			    void *data)
381 {
382 	int ret;
383 
384 	if (!csdev->enable) {
385 		if (source_ops(csdev)->enable) {
386 			ret = source_ops(csdev)->enable(csdev, data, mode);
387 			if (ret)
388 				return ret;
389 		}
390 		csdev->enable = true;
391 	}
392 
393 	atomic_inc(&csdev->refcnt);
394 
395 	return 0;
396 }
397 EXPORT_SYMBOL_GPL(coresight_enable_source);
398 
399 static bool coresight_is_helper(struct coresight_device *csdev)
400 {
401 	return csdev->type == CORESIGHT_DEV_TYPE_HELPER;
402 }
403 
404 static int coresight_enable_helper(struct coresight_device *csdev,
405 				   enum cs_mode mode, void *data)
406 {
407 	int ret;
408 
409 	if (!helper_ops(csdev)->enable)
410 		return 0;
411 	ret = helper_ops(csdev)->enable(csdev, mode, data);
412 	if (ret)
413 		return ret;
414 
415 	csdev->enable = true;
416 	return 0;
417 }
418 
419 static void coresight_disable_helper(struct coresight_device *csdev)
420 {
421 	int ret;
422 
423 	if (!helper_ops(csdev)->disable)
424 		return;
425 
426 	ret = helper_ops(csdev)->disable(csdev, NULL);
427 	if (ret)
428 		return;
429 	csdev->enable = false;
430 }
431 
432 static void coresight_disable_helpers(struct coresight_device *csdev)
433 {
434 	int i;
435 	struct coresight_device *helper;
436 
437 	for (i = 0; i < csdev->pdata->nr_outconns; ++i) {
438 		helper = csdev->pdata->out_conns[i]->dest_dev;
439 		if (helper && coresight_is_helper(helper))
440 			coresight_disable_helper(helper);
441 	}
442 }
443 
444 /*
445  * Helper function to call source_ops(csdev)->disable and also disable the
446  * helpers.
447  *
448  * There is an imbalance between coresight_enable_path() and
449  * coresight_disable_path(). Enabling also enables the source's helpers as part
450  * of the path, but disabling always skips the first item in the path (which is
451  * the source), so sources and their helpers don't get disabled as part of that
452  * function and we need the extra step here.
453  */
454 void coresight_disable_source(struct coresight_device *csdev, void *data)
455 {
456 	if (source_ops(csdev)->disable)
457 		source_ops(csdev)->disable(csdev, data);
458 	coresight_disable_helpers(csdev);
459 }
460 EXPORT_SYMBOL_GPL(coresight_disable_source);
461 
462 /**
463  *  coresight_disable_source_sysfs - Drop the reference count by 1 and disable
464  *  the device if there are no users left.
465  *
466  *  @csdev: The coresight device to disable
467  *  @data: Opaque data to pass on to the disable function of the source device.
468  *         For example in perf mode this is a pointer to the struct perf_event.
469  *
470  *  Returns true if the device has been disabled.
471  */
472 static bool coresight_disable_source_sysfs(struct coresight_device *csdev,
473 					   void *data)
474 {
475 	if (atomic_dec_return(&csdev->refcnt) == 0) {
476 		coresight_disable_source(csdev, data);
477 		csdev->enable = false;
478 	}
479 	return !csdev->enable;
480 }
481 
482 /*
483  * coresight_disable_path_from : Disable components in the given path beyond
484  * @nd in the list. If @nd is NULL, all the components, except the SOURCE are
485  * disabled.
486  */
487 static void coresight_disable_path_from(struct list_head *path,
488 					struct coresight_node *nd)
489 {
490 	u32 type;
491 	struct coresight_device *csdev, *parent, *child;
492 
493 	if (!nd)
494 		nd = list_first_entry(path, struct coresight_node, link);
495 
496 	list_for_each_entry_continue(nd, path, link) {
497 		csdev = nd->csdev;
498 		type = csdev->type;
499 
500 		/*
501 		 * ETF devices are tricky... They can be a link or a sink,
502 		 * depending on how they are configured.  If an ETF has been
503 		 * "activated" it will be configured as a sink, otherwise
504 		 * go ahead with the link configuration.
505 		 */
506 		if (type == CORESIGHT_DEV_TYPE_LINKSINK)
507 			type = (csdev == coresight_get_sink(path)) ?
508 						CORESIGHT_DEV_TYPE_SINK :
509 						CORESIGHT_DEV_TYPE_LINK;
510 
511 		switch (type) {
512 		case CORESIGHT_DEV_TYPE_SINK:
513 			coresight_disable_sink(csdev);
514 			break;
515 		case CORESIGHT_DEV_TYPE_SOURCE:
516 			/*
517 			 * We skip the first node in the path assuming that it
518 			 * is the source. So we don't expect a source device in
519 			 * the middle of a path.
520 			 */
521 			WARN_ON(1);
522 			break;
523 		case CORESIGHT_DEV_TYPE_LINK:
524 			parent = list_prev_entry(nd, link)->csdev;
525 			child = list_next_entry(nd, link)->csdev;
526 			coresight_disable_link(csdev, parent, child);
527 			break;
528 		default:
529 			break;
530 		}
531 
532 		/* Disable all helpers adjacent along the path last */
533 		coresight_disable_helpers(csdev);
534 	}
535 }
536 
537 void coresight_disable_path(struct list_head *path)
538 {
539 	coresight_disable_path_from(path, NULL);
540 }
541 EXPORT_SYMBOL_GPL(coresight_disable_path);
542 
543 static int coresight_enable_helpers(struct coresight_device *csdev,
544 				    enum cs_mode mode, void *data)
545 {
546 	int i, ret = 0;
547 	struct coresight_device *helper;
548 
549 	for (i = 0; i < csdev->pdata->nr_outconns; ++i) {
550 		helper = csdev->pdata->out_conns[i]->dest_dev;
551 		if (!helper || !coresight_is_helper(helper))
552 			continue;
553 
554 		ret = coresight_enable_helper(helper, mode, data);
555 		if (ret)
556 			return ret;
557 	}
558 
559 	return 0;
560 }
561 
562 int coresight_enable_path(struct list_head *path, enum cs_mode mode,
563 			  void *sink_data)
564 {
565 	int ret = 0;
566 	u32 type;
567 	struct coresight_node *nd;
568 	struct coresight_device *csdev, *parent, *child;
569 
570 	list_for_each_entry_reverse(nd, path, link) {
571 		csdev = nd->csdev;
572 		type = csdev->type;
573 
574 		/* Enable all helpers adjacent to the path first */
575 		ret = coresight_enable_helpers(csdev, mode, sink_data);
576 		if (ret)
577 			goto err;
578 		/*
579 		 * ETF devices are tricky... They can be a link or a sink,
580 		 * depending on how they are configured.  If an ETF has been
581 		 * "activated" it will be configured as a sink, otherwise
582 		 * go ahead with the link configuration.
583 		 */
584 		if (type == CORESIGHT_DEV_TYPE_LINKSINK)
585 			type = (csdev == coresight_get_sink(path)) ?
586 						CORESIGHT_DEV_TYPE_SINK :
587 						CORESIGHT_DEV_TYPE_LINK;
588 
589 		switch (type) {
590 		case CORESIGHT_DEV_TYPE_SINK:
591 			ret = coresight_enable_sink(csdev, mode, sink_data);
592 			/*
593 			 * Sink is the first component turned on. If we
594 			 * failed to enable the sink, there are no components
595 			 * that need disabling. Disabling the path here
596 			 * would mean we could disrupt an existing session.
597 			 */
598 			if (ret)
599 				goto out;
600 			break;
601 		case CORESIGHT_DEV_TYPE_SOURCE:
602 			/* sources are enabled from either sysFS or Perf */
603 			break;
604 		case CORESIGHT_DEV_TYPE_LINK:
605 			parent = list_prev_entry(nd, link)->csdev;
606 			child = list_next_entry(nd, link)->csdev;
607 			ret = coresight_enable_link(csdev, parent, child);
608 			if (ret)
609 				goto err;
610 			break;
611 		default:
612 			goto err;
613 		}
614 	}
615 
616 out:
617 	return ret;
618 err:
619 	coresight_disable_path_from(path, nd);
620 	goto out;
621 }
622 
623 struct coresight_device *coresight_get_sink(struct list_head *path)
624 {
625 	struct coresight_device *csdev;
626 
627 	if (!path)
628 		return NULL;
629 
630 	csdev = list_last_entry(path, struct coresight_node, link)->csdev;
631 	if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
632 	    csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
633 		return NULL;
634 
635 	return csdev;
636 }
637 
638 static struct coresight_device *
639 coresight_find_enabled_sink(struct coresight_device *csdev)
640 {
641 	int i;
642 	struct coresight_device *sink = NULL;
643 
644 	if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
645 	     csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
646 	     csdev->activated)
647 		return csdev;
648 
649 	/*
650 	 * Recursively explore each port found on this element.
651 	 */
652 	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
653 		struct coresight_device *child_dev;
654 
655 		child_dev = csdev->pdata->out_conns[i]->dest_dev;
656 		if (child_dev)
657 			sink = coresight_find_enabled_sink(child_dev);
658 		if (sink)
659 			return sink;
660 	}
661 
662 	return NULL;
663 }
664 
665 /**
666  * coresight_get_enabled_sink - returns the first enabled sink using
667  * connection based search starting from the source reference
668  *
669  * @source: Coresight source device reference
670  */
671 struct coresight_device *
672 coresight_get_enabled_sink(struct coresight_device *source)
673 {
674 	if (!source)
675 		return NULL;
676 
677 	return coresight_find_enabled_sink(source);
678 }
679 
680 static int coresight_sink_by_id(struct device *dev, const void *data)
681 {
682 	struct coresight_device *csdev = to_coresight_device(dev);
683 	unsigned long hash;
684 
685 	if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
686 	     csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
687 
688 		if (!csdev->ea)
689 			return 0;
690 		/*
691 		 * See function etm_perf_add_symlink_sink() to know where
692 		 * this comes from.
693 		 */
694 		hash = (unsigned long)csdev->ea->var;
695 
696 		if ((u32)hash == *(u32 *)data)
697 			return 1;
698 	}
699 
700 	return 0;
701 }
702 
703 /**
704  * coresight_get_sink_by_id - returns the sink that matches the id
705  * @id: Id of the sink to match
706  *
707  * The name of a sink is unique, whether it is found on the AMBA bus or
708  * otherwise.  As such the hash of that name can easily be used to identify
709  * a sink.
710  */
711 struct coresight_device *coresight_get_sink_by_id(u32 id)
712 {
713 	struct device *dev = NULL;
714 
715 	dev = bus_find_device(&coresight_bustype, NULL, &id,
716 			      coresight_sink_by_id);
717 
718 	return dev ? to_coresight_device(dev) : NULL;
719 }
720 
721 /**
722  * coresight_get_ref- Helper function to increase reference count to module
723  * and device.
724  *
725  * @csdev: The coresight device to get a reference on.
726  *
727  * Return true in successful case and power up the device.
728  * Return false when failed to get reference of module.
729  */
730 static inline bool coresight_get_ref(struct coresight_device *csdev)
731 {
732 	struct device *dev = csdev->dev.parent;
733 
734 	/* Make sure the driver can't be removed */
735 	if (!try_module_get(dev->driver->owner))
736 		return false;
737 	/* Make sure the device can't go away */
738 	get_device(dev);
739 	pm_runtime_get_sync(dev);
740 	return true;
741 }
742 
743 /**
744  * coresight_put_ref- Helper function to decrease reference count to module
745  * and device. Power off the device.
746  *
747  * @csdev: The coresight device to decrement a reference from.
748  */
749 static inline void coresight_put_ref(struct coresight_device *csdev)
750 {
751 	struct device *dev = csdev->dev.parent;
752 
753 	pm_runtime_put(dev);
754 	put_device(dev);
755 	module_put(dev->driver->owner);
756 }
757 
758 /*
759  * coresight_grab_device - Power up this device and any of the helper
760  * devices connected to it for trace operation. Since the helper devices
761  * don't appear on the trace path, they should be handled along with the
762  * master device.
763  */
764 static int coresight_grab_device(struct coresight_device *csdev)
765 {
766 	int i;
767 
768 	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
769 		struct coresight_device *child;
770 
771 		child = csdev->pdata->out_conns[i]->dest_dev;
772 		if (child && coresight_is_helper(child))
773 			if (!coresight_get_ref(child))
774 				goto err;
775 	}
776 	if (coresight_get_ref(csdev))
777 		return 0;
778 err:
779 	for (i--; i >= 0; i--) {
780 		struct coresight_device *child;
781 
782 		child = csdev->pdata->out_conns[i]->dest_dev;
783 		if (child && coresight_is_helper(child))
784 			coresight_put_ref(child);
785 	}
786 	return -ENODEV;
787 }
788 
789 /*
790  * coresight_drop_device - Release this device and any of the helper
791  * devices connected to it.
792  */
793 static void coresight_drop_device(struct coresight_device *csdev)
794 {
795 	int i;
796 
797 	coresight_put_ref(csdev);
798 	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
799 		struct coresight_device *child;
800 
801 		child = csdev->pdata->out_conns[i]->dest_dev;
802 		if (child && coresight_is_helper(child))
803 			coresight_put_ref(child);
804 	}
805 }
806 
807 /**
808  * _coresight_build_path - recursively build a path from a @csdev to a sink.
809  * @csdev:	The device to start from.
810  * @sink:	The final sink we want in this path.
811  * @path:	The list to add devices to.
812  *
813  * The tree of Coresight device is traversed until an activated sink is
814  * found.  From there the sink is added to the list along with all the
815  * devices that led to that point - the end result is a list from source
816  * to sink. In that list the source is the first device and the sink the
817  * last one.
818  */
819 static int _coresight_build_path(struct coresight_device *csdev,
820 				 struct coresight_device *sink,
821 				 struct list_head *path)
822 {
823 	int i, ret;
824 	bool found = false;
825 	struct coresight_node *node;
826 
827 	/* An activated sink has been found.  Enqueue the element */
828 	if (csdev == sink)
829 		goto out;
830 
831 	if (coresight_is_percpu_source(csdev) && coresight_is_percpu_sink(sink) &&
832 	    sink == per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev))) {
833 		if (_coresight_build_path(sink, sink, path) == 0) {
834 			found = true;
835 			goto out;
836 		}
837 	}
838 
839 	/* Not a sink - recursively explore each port found on this element */
840 	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
841 		struct coresight_device *child_dev;
842 
843 		child_dev = csdev->pdata->out_conns[i]->dest_dev;
844 		if (child_dev &&
845 		    _coresight_build_path(child_dev, sink, path) == 0) {
846 			found = true;
847 			break;
848 		}
849 	}
850 
851 	if (!found)
852 		return -ENODEV;
853 
854 out:
855 	/*
856 	 * A path from this element to a sink has been found.  The elements
857 	 * leading to the sink are already enqueued, all that is left to do
858 	 * is tell the PM runtime core we need this element and add a node
859 	 * for it.
860 	 */
861 	ret = coresight_grab_device(csdev);
862 	if (ret)
863 		return ret;
864 
865 	node = kzalloc(sizeof(struct coresight_node), GFP_KERNEL);
866 	if (!node)
867 		return -ENOMEM;
868 
869 	node->csdev = csdev;
870 	list_add(&node->link, path);
871 
872 	return 0;
873 }
874 
875 struct list_head *coresight_build_path(struct coresight_device *source,
876 				       struct coresight_device *sink)
877 {
878 	struct list_head *path;
879 	int rc;
880 
881 	if (!sink)
882 		return ERR_PTR(-EINVAL);
883 
884 	path = kzalloc(sizeof(struct list_head), GFP_KERNEL);
885 	if (!path)
886 		return ERR_PTR(-ENOMEM);
887 
888 	INIT_LIST_HEAD(path);
889 
890 	rc = _coresight_build_path(source, sink, path);
891 	if (rc) {
892 		kfree(path);
893 		return ERR_PTR(rc);
894 	}
895 
896 	return path;
897 }
898 
899 /**
900  * coresight_release_path - release a previously built path.
901  * @path:	the path to release.
902  *
903  * Go through all the elements of a path and 1) removed it from the list and
904  * 2) free the memory allocated for each node.
905  */
906 void coresight_release_path(struct list_head *path)
907 {
908 	struct coresight_device *csdev;
909 	struct coresight_node *nd, *next;
910 
911 	list_for_each_entry_safe(nd, next, path, link) {
912 		csdev = nd->csdev;
913 
914 		coresight_drop_device(csdev);
915 		list_del(&nd->link);
916 		kfree(nd);
917 	}
918 
919 	kfree(path);
920 }
921 
922 /* return true if the device is a suitable type for a default sink */
923 static inline bool coresight_is_def_sink_type(struct coresight_device *csdev)
924 {
925 	/* sink & correct subtype */
926 	if (((csdev->type == CORESIGHT_DEV_TYPE_SINK) ||
927 	     (csdev->type == CORESIGHT_DEV_TYPE_LINKSINK)) &&
928 	    (csdev->subtype.sink_subtype >= CORESIGHT_DEV_SUBTYPE_SINK_BUFFER))
929 		return true;
930 	return false;
931 }
932 
933 /**
934  * coresight_select_best_sink - return the best sink for use as default from
935  * the two provided.
936  *
937  * @sink:	current best sink.
938  * @depth:      search depth where current sink was found.
939  * @new_sink:	new sink for comparison with current sink.
940  * @new_depth:  search depth where new sink was found.
941  *
942  * Sinks prioritised according to coresight_dev_subtype_sink, with only
943  * subtypes CORESIGHT_DEV_SUBTYPE_SINK_BUFFER or higher being used.
944  *
945  * Where two sinks of equal priority are found, the sink closest to the
946  * source is used (smallest search depth).
947  *
948  * return @new_sink & update @depth if better than @sink, else return @sink.
949  */
950 static struct coresight_device *
951 coresight_select_best_sink(struct coresight_device *sink, int *depth,
952 			   struct coresight_device *new_sink, int new_depth)
953 {
954 	bool update = false;
955 
956 	if (!sink) {
957 		/* first found at this level */
958 		update = true;
959 	} else if (new_sink->subtype.sink_subtype >
960 		   sink->subtype.sink_subtype) {
961 		/* found better sink */
962 		update = true;
963 	} else if ((new_sink->subtype.sink_subtype ==
964 		    sink->subtype.sink_subtype) &&
965 		   (*depth > new_depth)) {
966 		/* found same but closer sink */
967 		update = true;
968 	}
969 
970 	if (update)
971 		*depth = new_depth;
972 	return update ? new_sink : sink;
973 }
974 
975 /**
976  * coresight_find_sink - recursive function to walk trace connections from
977  * source to find a suitable default sink.
978  *
979  * @csdev: source / current device to check.
980  * @depth: [in] search depth of calling dev, [out] depth of found sink.
981  *
982  * This will walk the connection path from a source (ETM) till a suitable
983  * sink is encountered and return that sink to the original caller.
984  *
985  * If current device is a plain sink return that & depth, otherwise recursively
986  * call child connections looking for a sink. Select best possible using
987  * coresight_select_best_sink.
988  *
989  * return best sink found, or NULL if not found at this node or child nodes.
990  */
991 static struct coresight_device *
992 coresight_find_sink(struct coresight_device *csdev, int *depth)
993 {
994 	int i, curr_depth = *depth + 1, found_depth = 0;
995 	struct coresight_device *found_sink = NULL;
996 
997 	if (coresight_is_def_sink_type(csdev)) {
998 		found_depth = curr_depth;
999 		found_sink = csdev;
1000 		if (csdev->type == CORESIGHT_DEV_TYPE_SINK)
1001 			goto return_def_sink;
1002 		/* look past LINKSINK for something better */
1003 	}
1004 
1005 	/*
1006 	 * Not a sink we want - or possible child sink may be better.
1007 	 * recursively explore each port found on this element.
1008 	 */
1009 	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
1010 		struct coresight_device *child_dev, *sink = NULL;
1011 		int child_depth = curr_depth;
1012 
1013 		child_dev = csdev->pdata->out_conns[i]->dest_dev;
1014 		if (child_dev)
1015 			sink = coresight_find_sink(child_dev, &child_depth);
1016 
1017 		if (sink)
1018 			found_sink = coresight_select_best_sink(found_sink,
1019 								&found_depth,
1020 								sink,
1021 								child_depth);
1022 	}
1023 
1024 return_def_sink:
1025 	/* return found sink and depth */
1026 	if (found_sink)
1027 		*depth = found_depth;
1028 	return found_sink;
1029 }
1030 
1031 /**
1032  * coresight_find_default_sink: Find a sink suitable for use as a
1033  * default sink.
1034  *
1035  * @csdev: starting source to find a connected sink.
1036  *
1037  * Walks connections graph looking for a suitable sink to enable for the
1038  * supplied source. Uses CoreSight device subtypes and distance from source
1039  * to select the best sink.
1040  *
1041  * If a sink is found, then the default sink for this device is set and
1042  * will be automatically used in future.
1043  *
1044  * Used in cases where the CoreSight user (perf / sysfs) has not selected a
1045  * sink.
1046  */
1047 struct coresight_device *
1048 coresight_find_default_sink(struct coresight_device *csdev)
1049 {
1050 	int depth = 0;
1051 
1052 	/* look for a default sink if we have not found for this device */
1053 	if (!csdev->def_sink) {
1054 		if (coresight_is_percpu_source(csdev))
1055 			csdev->def_sink = per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev));
1056 		if (!csdev->def_sink)
1057 			csdev->def_sink = coresight_find_sink(csdev, &depth);
1058 	}
1059 	return csdev->def_sink;
1060 }
1061 
1062 static int coresight_remove_sink_ref(struct device *dev, void *data)
1063 {
1064 	struct coresight_device *sink = data;
1065 	struct coresight_device *source = to_coresight_device(dev);
1066 
1067 	if (source->def_sink == sink)
1068 		source->def_sink = NULL;
1069 	return 0;
1070 }
1071 
1072 /**
1073  * coresight_clear_default_sink: Remove all default sink references to the
1074  * supplied sink.
1075  *
1076  * If supplied device is a sink, then check all the bus devices and clear
1077  * out all the references to this sink from the coresight_device def_sink
1078  * parameter.
1079  *
1080  * @csdev: coresight sink - remove references to this from all sources.
1081  */
1082 static void coresight_clear_default_sink(struct coresight_device *csdev)
1083 {
1084 	if ((csdev->type == CORESIGHT_DEV_TYPE_SINK) ||
1085 	    (csdev->type == CORESIGHT_DEV_TYPE_LINKSINK)) {
1086 		bus_for_each_dev(&coresight_bustype, NULL, csdev,
1087 				 coresight_remove_sink_ref);
1088 	}
1089 }
1090 
1091 /** coresight_validate_source - make sure a source has the right credentials
1092  *  @csdev:	the device structure for a source.
1093  *  @function:	the function this was called from.
1094  *
1095  * Assumes the coresight_mutex is held.
1096  */
1097 static int coresight_validate_source(struct coresight_device *csdev,
1098 				     const char *function)
1099 {
1100 	u32 type, subtype;
1101 
1102 	type = csdev->type;
1103 	subtype = csdev->subtype.source_subtype;
1104 
1105 	if (type != CORESIGHT_DEV_TYPE_SOURCE) {
1106 		dev_err(&csdev->dev, "wrong device type in %s\n", function);
1107 		return -EINVAL;
1108 	}
1109 
1110 	if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC &&
1111 	    subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE &&
1112 	    subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS) {
1113 		dev_err(&csdev->dev, "wrong device subtype in %s\n", function);
1114 		return -EINVAL;
1115 	}
1116 
1117 	return 0;
1118 }
1119 
1120 int coresight_enable(struct coresight_device *csdev)
1121 {
1122 	int cpu, ret = 0;
1123 	struct coresight_device *sink;
1124 	struct list_head *path;
1125 	enum coresight_dev_subtype_source subtype;
1126 	u32 hash;
1127 
1128 	subtype = csdev->subtype.source_subtype;
1129 
1130 	mutex_lock(&coresight_mutex);
1131 
1132 	ret = coresight_validate_source(csdev, __func__);
1133 	if (ret)
1134 		goto out;
1135 
1136 	if (csdev->enable) {
1137 		/*
1138 		 * There could be multiple applications driving the software
1139 		 * source. So keep the refcount for each such user when the
1140 		 * source is already enabled.
1141 		 */
1142 		if (subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE)
1143 			atomic_inc(&csdev->refcnt);
1144 		goto out;
1145 	}
1146 
1147 	sink = coresight_get_enabled_sink(csdev);
1148 	if (!sink) {
1149 		ret = -EINVAL;
1150 		goto out;
1151 	}
1152 
1153 	path = coresight_build_path(csdev, sink);
1154 	if (IS_ERR(path)) {
1155 		pr_err("building path(s) failed\n");
1156 		ret = PTR_ERR(path);
1157 		goto out;
1158 	}
1159 
1160 	ret = coresight_enable_path(path, CS_MODE_SYSFS, NULL);
1161 	if (ret)
1162 		goto err_path;
1163 
1164 	ret = coresight_enable_source(csdev, CS_MODE_SYSFS, NULL);
1165 	if (ret)
1166 		goto err_source;
1167 
1168 	switch (subtype) {
1169 	case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
1170 		/*
1171 		 * When working from sysFS it is important to keep track
1172 		 * of the paths that were created so that they can be
1173 		 * undone in 'coresight_disable()'.  Since there can only
1174 		 * be a single session per tracer (when working from sysFS)
1175 		 * a per-cpu variable will do just fine.
1176 		 */
1177 		cpu = source_ops(csdev)->cpu_id(csdev);
1178 		per_cpu(tracer_path, cpu) = path;
1179 		break;
1180 	case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
1181 	case CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS:
1182 		/*
1183 		 * Use the hash of source's device name as ID
1184 		 * and map the ID to the pointer of the path.
1185 		 */
1186 		hash = hashlen_hash(hashlen_string(NULL, dev_name(&csdev->dev)));
1187 		ret = idr_alloc_u32(&path_idr, path, &hash, hash, GFP_KERNEL);
1188 		if (ret)
1189 			goto err_source;
1190 		break;
1191 	default:
1192 		/* We can't be here */
1193 		break;
1194 	}
1195 
1196 out:
1197 	mutex_unlock(&coresight_mutex);
1198 	return ret;
1199 
1200 err_source:
1201 	coresight_disable_path(path);
1202 
1203 err_path:
1204 	coresight_release_path(path);
1205 	goto out;
1206 }
1207 EXPORT_SYMBOL_GPL(coresight_enable);
1208 
1209 void coresight_disable(struct coresight_device *csdev)
1210 {
1211 	int cpu, ret;
1212 	struct list_head *path = NULL;
1213 	u32 hash;
1214 
1215 	mutex_lock(&coresight_mutex);
1216 
1217 	ret = coresight_validate_source(csdev, __func__);
1218 	if (ret)
1219 		goto out;
1220 
1221 	if (!csdev->enable || !coresight_disable_source_sysfs(csdev, NULL))
1222 		goto out;
1223 
1224 	switch (csdev->subtype.source_subtype) {
1225 	case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
1226 		cpu = source_ops(csdev)->cpu_id(csdev);
1227 		path = per_cpu(tracer_path, cpu);
1228 		per_cpu(tracer_path, cpu) = NULL;
1229 		break;
1230 	case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
1231 	case CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS:
1232 		hash = hashlen_hash(hashlen_string(NULL, dev_name(&csdev->dev)));
1233 		/* Find the path by the hash. */
1234 		path = idr_find(&path_idr, hash);
1235 		if (path == NULL) {
1236 			pr_err("Path is not found for %s\n", dev_name(&csdev->dev));
1237 			goto out;
1238 		}
1239 		idr_remove(&path_idr, hash);
1240 		break;
1241 	default:
1242 		/* We can't be here */
1243 		break;
1244 	}
1245 
1246 	coresight_disable_path(path);
1247 	coresight_release_path(path);
1248 
1249 out:
1250 	mutex_unlock(&coresight_mutex);
1251 }
1252 EXPORT_SYMBOL_GPL(coresight_disable);
1253 
1254 static ssize_t enable_sink_show(struct device *dev,
1255 				struct device_attribute *attr, char *buf)
1256 {
1257 	struct coresight_device *csdev = to_coresight_device(dev);
1258 
1259 	return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->activated);
1260 }
1261 
1262 static ssize_t enable_sink_store(struct device *dev,
1263 				 struct device_attribute *attr,
1264 				 const char *buf, size_t size)
1265 {
1266 	int ret;
1267 	unsigned long val;
1268 	struct coresight_device *csdev = to_coresight_device(dev);
1269 
1270 	ret = kstrtoul(buf, 10, &val);
1271 	if (ret)
1272 		return ret;
1273 
1274 	if (val)
1275 		csdev->activated = true;
1276 	else
1277 		csdev->activated = false;
1278 
1279 	return size;
1280 
1281 }
1282 static DEVICE_ATTR_RW(enable_sink);
1283 
1284 static ssize_t enable_source_show(struct device *dev,
1285 				  struct device_attribute *attr, char *buf)
1286 {
1287 	struct coresight_device *csdev = to_coresight_device(dev);
1288 
1289 	return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->enable);
1290 }
1291 
1292 static ssize_t enable_source_store(struct device *dev,
1293 				   struct device_attribute *attr,
1294 				   const char *buf, size_t size)
1295 {
1296 	int ret = 0;
1297 	unsigned long val;
1298 	struct coresight_device *csdev = to_coresight_device(dev);
1299 
1300 	ret = kstrtoul(buf, 10, &val);
1301 	if (ret)
1302 		return ret;
1303 
1304 	if (val) {
1305 		ret = coresight_enable(csdev);
1306 		if (ret)
1307 			return ret;
1308 	} else {
1309 		coresight_disable(csdev);
1310 	}
1311 
1312 	return size;
1313 }
1314 static DEVICE_ATTR_RW(enable_source);
1315 
1316 static struct attribute *coresight_sink_attrs[] = {
1317 	&dev_attr_enable_sink.attr,
1318 	NULL,
1319 };
1320 ATTRIBUTE_GROUPS(coresight_sink);
1321 
1322 static struct attribute *coresight_source_attrs[] = {
1323 	&dev_attr_enable_source.attr,
1324 	NULL,
1325 };
1326 ATTRIBUTE_GROUPS(coresight_source);
1327 
1328 static struct device_type coresight_dev_type[] = {
1329 	{
1330 		.name = "sink",
1331 		.groups = coresight_sink_groups,
1332 	},
1333 	{
1334 		.name = "link",
1335 	},
1336 	{
1337 		.name = "linksink",
1338 		.groups = coresight_sink_groups,
1339 	},
1340 	{
1341 		.name = "source",
1342 		.groups = coresight_source_groups,
1343 	},
1344 	{
1345 		.name = "helper",
1346 	}
1347 };
1348 /* Ensure the enum matches the names and groups */
1349 static_assert(ARRAY_SIZE(coresight_dev_type) == CORESIGHT_DEV_TYPE_MAX);
1350 
1351 static void coresight_device_release(struct device *dev)
1352 {
1353 	struct coresight_device *csdev = to_coresight_device(dev);
1354 
1355 	fwnode_handle_put(csdev->dev.fwnode);
1356 	kfree(csdev);
1357 }
1358 
1359 static int coresight_orphan_match(struct device *dev, void *data)
1360 {
1361 	int i, ret = 0;
1362 	bool still_orphan = false;
1363 	struct coresight_device *dst_csdev = data;
1364 	struct coresight_device *src_csdev = to_coresight_device(dev);
1365 	struct coresight_connection *conn;
1366 	bool fixup_self = (src_csdev == dst_csdev);
1367 
1368 	/* Move on to another component if no connection is orphan */
1369 	if (!src_csdev->orphan)
1370 		return 0;
1371 	/*
1372 	 * Circle through all the connections of that component.  If we find
1373 	 * an orphan connection whose name matches @dst_csdev, link it.
1374 	 */
1375 	for (i = 0; i < src_csdev->pdata->nr_outconns; i++) {
1376 		conn = src_csdev->pdata->out_conns[i];
1377 
1378 		/* Skip the port if it's already connected. */
1379 		if (conn->dest_dev)
1380 			continue;
1381 
1382 		/*
1383 		 * If we are at the "new" device, which triggered this search,
1384 		 * we must find the remote device from the fwnode in the
1385 		 * connection.
1386 		 */
1387 		if (fixup_self)
1388 			dst_csdev = coresight_find_csdev_by_fwnode(
1389 				conn->dest_fwnode);
1390 
1391 		/* Does it match this newly added device? */
1392 		if (dst_csdev && conn->dest_fwnode == dst_csdev->dev.fwnode) {
1393 			ret = coresight_make_links(src_csdev, conn, dst_csdev);
1394 			if (ret)
1395 				return ret;
1396 
1397 			/*
1398 			 * Install the device connection. This also indicates that
1399 			 * the links are operational on both ends.
1400 			 */
1401 			conn->dest_dev = dst_csdev;
1402 			conn->src_dev = src_csdev;
1403 
1404 			ret = coresight_add_in_conn(conn);
1405 			if (ret)
1406 				return ret;
1407 		} else {
1408 			/* This component still has an orphan */
1409 			still_orphan = true;
1410 		}
1411 	}
1412 
1413 	src_csdev->orphan = still_orphan;
1414 
1415 	/*
1416 	 * Returning '0' in case we didn't encounter any error,
1417 	 * ensures that all known component on the bus will be checked.
1418 	 */
1419 	return 0;
1420 }
1421 
1422 static int coresight_fixup_orphan_conns(struct coresight_device *csdev)
1423 {
1424 	return bus_for_each_dev(&coresight_bustype, NULL,
1425 			 csdev, coresight_orphan_match);
1426 }
1427 
1428 /* coresight_remove_conns - Remove other device's references to this device */
1429 static void coresight_remove_conns(struct coresight_device *csdev)
1430 {
1431 	int i, j;
1432 	struct coresight_connection *conn;
1433 
1434 	/*
1435 	 * Remove the input connection references from the destination device
1436 	 * for each output connection.
1437 	 */
1438 	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
1439 		conn = csdev->pdata->out_conns[i];
1440 		if (!conn->dest_dev)
1441 			continue;
1442 
1443 		for (j = 0; j < conn->dest_dev->pdata->nr_inconns; ++j)
1444 			if (conn->dest_dev->pdata->in_conns[j] == conn) {
1445 				conn->dest_dev->pdata->in_conns[j] = NULL;
1446 				break;
1447 			}
1448 	}
1449 
1450 	/*
1451 	 * For all input connections, remove references to this device.
1452 	 * Connection objects are shared so modifying this device's input
1453 	 * connections affects the other device's output connection.
1454 	 */
1455 	for (i = 0; i < csdev->pdata->nr_inconns; ++i) {
1456 		conn = csdev->pdata->in_conns[i];
1457 		/* Input conns array is sparse */
1458 		if (!conn)
1459 			continue;
1460 
1461 		conn->src_dev->orphan = true;
1462 		coresight_remove_links(conn->src_dev, conn);
1463 		conn->dest_dev = NULL;
1464 	}
1465 }
1466 
1467 /**
1468  * coresight_timeout - loop until a bit has changed to a specific register
1469  *			state.
1470  * @csa: coresight device access for the device
1471  * @offset: Offset of the register from the base of the device.
1472  * @position: the position of the bit of interest.
1473  * @value: the value the bit should have.
1474  *
1475  * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
1476  * TIMEOUT_US has elapsed, which ever happens first.
1477  */
1478 int coresight_timeout(struct csdev_access *csa, u32 offset,
1479 		      int position, int value)
1480 {
1481 	int i;
1482 	u32 val;
1483 
1484 	for (i = TIMEOUT_US; i > 0; i--) {
1485 		val = csdev_access_read32(csa, offset);
1486 		/* waiting on the bit to go from 0 to 1 */
1487 		if (value) {
1488 			if (val & BIT(position))
1489 				return 0;
1490 		/* waiting on the bit to go from 1 to 0 */
1491 		} else {
1492 			if (!(val & BIT(position)))
1493 				return 0;
1494 		}
1495 
1496 		/*
1497 		 * Delay is arbitrary - the specification doesn't say how long
1498 		 * we are expected to wait.  Extra check required to make sure
1499 		 * we don't wait needlessly on the last iteration.
1500 		 */
1501 		if (i - 1)
1502 			udelay(1);
1503 	}
1504 
1505 	return -EAGAIN;
1506 }
1507 EXPORT_SYMBOL_GPL(coresight_timeout);
1508 
1509 u32 coresight_relaxed_read32(struct coresight_device *csdev, u32 offset)
1510 {
1511 	return csdev_access_relaxed_read32(&csdev->access, offset);
1512 }
1513 
1514 u32 coresight_read32(struct coresight_device *csdev, u32 offset)
1515 {
1516 	return csdev_access_read32(&csdev->access, offset);
1517 }
1518 
1519 void coresight_relaxed_write32(struct coresight_device *csdev,
1520 			       u32 val, u32 offset)
1521 {
1522 	csdev_access_relaxed_write32(&csdev->access, val, offset);
1523 }
1524 
1525 void coresight_write32(struct coresight_device *csdev, u32 val, u32 offset)
1526 {
1527 	csdev_access_write32(&csdev->access, val, offset);
1528 }
1529 
1530 u64 coresight_relaxed_read64(struct coresight_device *csdev, u32 offset)
1531 {
1532 	return csdev_access_relaxed_read64(&csdev->access, offset);
1533 }
1534 
1535 u64 coresight_read64(struct coresight_device *csdev, u32 offset)
1536 {
1537 	return csdev_access_read64(&csdev->access, offset);
1538 }
1539 
1540 void coresight_relaxed_write64(struct coresight_device *csdev,
1541 			       u64 val, u32 offset)
1542 {
1543 	csdev_access_relaxed_write64(&csdev->access, val, offset);
1544 }
1545 
1546 void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset)
1547 {
1548 	csdev_access_write64(&csdev->access, val, offset);
1549 }
1550 
1551 /*
1552  * coresight_release_platform_data: Release references to the devices connected
1553  * to the output port of this device.
1554  */
1555 void coresight_release_platform_data(struct coresight_device *csdev,
1556 				     struct device *dev,
1557 				     struct coresight_platform_data *pdata)
1558 {
1559 	int i;
1560 	struct coresight_connection **conns = pdata->out_conns;
1561 
1562 	for (i = 0; i < pdata->nr_outconns; i++) {
1563 		/* If we have made the links, remove them now */
1564 		if (csdev && conns[i]->dest_dev)
1565 			coresight_remove_links(csdev, conns[i]);
1566 		/*
1567 		 * Drop the refcount and clear the handle as this device
1568 		 * is going away
1569 		 */
1570 		fwnode_handle_put(conns[i]->dest_fwnode);
1571 		conns[i]->dest_fwnode = NULL;
1572 		devm_kfree(dev, conns[i]);
1573 	}
1574 	devm_kfree(dev, pdata->out_conns);
1575 	devm_kfree(dev, pdata->in_conns);
1576 	devm_kfree(dev, pdata);
1577 	if (csdev)
1578 		coresight_remove_conns_sysfs_group(csdev);
1579 }
1580 
1581 struct coresight_device *coresight_register(struct coresight_desc *desc)
1582 {
1583 	int ret;
1584 	struct coresight_device *csdev;
1585 	bool registered = false;
1586 
1587 	csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
1588 	if (!csdev) {
1589 		ret = -ENOMEM;
1590 		goto err_out;
1591 	}
1592 
1593 	csdev->pdata = desc->pdata;
1594 
1595 	csdev->type = desc->type;
1596 	csdev->subtype = desc->subtype;
1597 	csdev->ops = desc->ops;
1598 	csdev->access = desc->access;
1599 	csdev->orphan = true;
1600 
1601 	csdev->dev.type = &coresight_dev_type[desc->type];
1602 	csdev->dev.groups = desc->groups;
1603 	csdev->dev.parent = desc->dev;
1604 	csdev->dev.release = coresight_device_release;
1605 	csdev->dev.bus = &coresight_bustype;
1606 	/*
1607 	 * Hold the reference to our parent device. This will be
1608 	 * dropped only in coresight_device_release().
1609 	 */
1610 	csdev->dev.fwnode = fwnode_handle_get(dev_fwnode(desc->dev));
1611 	dev_set_name(&csdev->dev, "%s", desc->name);
1612 
1613 	/*
1614 	 * Make sure the device registration and the connection fixup
1615 	 * are synchronised, so that we don't see uninitialised devices
1616 	 * on the coresight bus while trying to resolve the connections.
1617 	 */
1618 	mutex_lock(&coresight_mutex);
1619 
1620 	ret = device_register(&csdev->dev);
1621 	if (ret) {
1622 		put_device(&csdev->dev);
1623 		/*
1624 		 * All resources are free'd explicitly via
1625 		 * coresight_device_release(), triggered from put_device().
1626 		 */
1627 		goto out_unlock;
1628 	}
1629 
1630 	if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
1631 	    csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
1632 		ret = etm_perf_add_symlink_sink(csdev);
1633 
1634 		if (ret) {
1635 			device_unregister(&csdev->dev);
1636 			/*
1637 			 * As with the above, all resources are free'd
1638 			 * explicitly via coresight_device_release() triggered
1639 			 * from put_device(), which is in turn called from
1640 			 * function device_unregister().
1641 			 */
1642 			goto out_unlock;
1643 		}
1644 	}
1645 	/* Device is now registered */
1646 	registered = true;
1647 
1648 	ret = coresight_create_conns_sysfs_group(csdev);
1649 	if (!ret)
1650 		ret = coresight_fixup_orphan_conns(csdev);
1651 
1652 out_unlock:
1653 	mutex_unlock(&coresight_mutex);
1654 	/* Success */
1655 	if (!ret) {
1656 		if (cti_assoc_ops && cti_assoc_ops->add)
1657 			cti_assoc_ops->add(csdev);
1658 		return csdev;
1659 	}
1660 
1661 	/* Unregister the device if needed */
1662 	if (registered) {
1663 		coresight_unregister(csdev);
1664 		return ERR_PTR(ret);
1665 	}
1666 
1667 err_out:
1668 	/* Cleanup the connection information */
1669 	coresight_release_platform_data(NULL, desc->dev, desc->pdata);
1670 	return ERR_PTR(ret);
1671 }
1672 EXPORT_SYMBOL_GPL(coresight_register);
1673 
1674 void coresight_unregister(struct coresight_device *csdev)
1675 {
1676 	etm_perf_del_symlink_sink(csdev);
1677 	/* Remove references of that device in the topology */
1678 	if (cti_assoc_ops && cti_assoc_ops->remove)
1679 		cti_assoc_ops->remove(csdev);
1680 	coresight_remove_conns(csdev);
1681 	coresight_clear_default_sink(csdev);
1682 	coresight_release_platform_data(csdev, csdev->dev.parent, csdev->pdata);
1683 	device_unregister(&csdev->dev);
1684 }
1685 EXPORT_SYMBOL_GPL(coresight_unregister);
1686 
1687 
1688 /*
1689  * coresight_search_device_idx - Search the fwnode handle of a device
1690  * in the given dev_idx list. Must be called with the coresight_mutex held.
1691  *
1692  * Returns the index of the entry, when found. Otherwise, -ENOENT.
1693  */
1694 static inline int coresight_search_device_idx(struct coresight_dev_list *dict,
1695 					      struct fwnode_handle *fwnode)
1696 {
1697 	int i;
1698 
1699 	for (i = 0; i < dict->nr_idx; i++)
1700 		if (dict->fwnode_list[i] == fwnode)
1701 			return i;
1702 	return -ENOENT;
1703 }
1704 
1705 static bool coresight_compare_type(enum coresight_dev_type type_a,
1706 				   union coresight_dev_subtype subtype_a,
1707 				   enum coresight_dev_type type_b,
1708 				   union coresight_dev_subtype subtype_b)
1709 {
1710 	if (type_a != type_b)
1711 		return false;
1712 
1713 	switch (type_a) {
1714 	case CORESIGHT_DEV_TYPE_SINK:
1715 		return subtype_a.sink_subtype == subtype_b.sink_subtype;
1716 	case CORESIGHT_DEV_TYPE_LINK:
1717 		return subtype_a.link_subtype == subtype_b.link_subtype;
1718 	case CORESIGHT_DEV_TYPE_LINKSINK:
1719 		return subtype_a.link_subtype == subtype_b.link_subtype &&
1720 		       subtype_a.sink_subtype == subtype_b.sink_subtype;
1721 	case CORESIGHT_DEV_TYPE_SOURCE:
1722 		return subtype_a.source_subtype == subtype_b.source_subtype;
1723 	case CORESIGHT_DEV_TYPE_HELPER:
1724 		return subtype_a.helper_subtype == subtype_b.helper_subtype;
1725 	default:
1726 		return false;
1727 	}
1728 }
1729 
1730 struct coresight_device *
1731 coresight_find_input_type(struct coresight_platform_data *pdata,
1732 			  enum coresight_dev_type type,
1733 			  union coresight_dev_subtype subtype)
1734 {
1735 	int i;
1736 	struct coresight_connection *conn;
1737 
1738 	for (i = 0; i < pdata->nr_inconns; ++i) {
1739 		conn = pdata->in_conns[i];
1740 		if (conn &&
1741 		    coresight_compare_type(type, subtype, conn->src_dev->type,
1742 					   conn->src_dev->subtype))
1743 			return conn->src_dev;
1744 	}
1745 	return NULL;
1746 }
1747 EXPORT_SYMBOL_GPL(coresight_find_input_type);
1748 
1749 struct coresight_device *
1750 coresight_find_output_type(struct coresight_platform_data *pdata,
1751 			   enum coresight_dev_type type,
1752 			   union coresight_dev_subtype subtype)
1753 {
1754 	int i;
1755 	struct coresight_connection *conn;
1756 
1757 	for (i = 0; i < pdata->nr_outconns; ++i) {
1758 		conn = pdata->out_conns[i];
1759 		if (conn->dest_dev &&
1760 		    coresight_compare_type(type, subtype, conn->dest_dev->type,
1761 					   conn->dest_dev->subtype))
1762 			return conn->dest_dev;
1763 	}
1764 	return NULL;
1765 }
1766 EXPORT_SYMBOL_GPL(coresight_find_output_type);
1767 
1768 bool coresight_loses_context_with_cpu(struct device *dev)
1769 {
1770 	return fwnode_property_present(dev_fwnode(dev),
1771 				       "arm,coresight-loses-context-with-cpu");
1772 }
1773 EXPORT_SYMBOL_GPL(coresight_loses_context_with_cpu);
1774 
1775 /*
1776  * coresight_alloc_device_name - Get an index for a given device in the
1777  * device index list specific to a driver. An index is allocated for a
1778  * device and is tracked with the fwnode_handle to prevent allocating
1779  * duplicate indices for the same device (e.g, if we defer probing of
1780  * a device due to dependencies), in case the index is requested again.
1781  */
1782 char *coresight_alloc_device_name(struct coresight_dev_list *dict,
1783 				  struct device *dev)
1784 {
1785 	int idx;
1786 	char *name = NULL;
1787 	struct fwnode_handle **list;
1788 
1789 	mutex_lock(&coresight_mutex);
1790 
1791 	idx = coresight_search_device_idx(dict, dev_fwnode(dev));
1792 	if (idx < 0) {
1793 		/* Make space for the new entry */
1794 		idx = dict->nr_idx;
1795 		list = krealloc_array(dict->fwnode_list,
1796 				      idx + 1, sizeof(*dict->fwnode_list),
1797 				      GFP_KERNEL);
1798 		if (ZERO_OR_NULL_PTR(list)) {
1799 			idx = -ENOMEM;
1800 			goto done;
1801 		}
1802 
1803 		list[idx] = dev_fwnode(dev);
1804 		dict->fwnode_list = list;
1805 		dict->nr_idx = idx + 1;
1806 	}
1807 
1808 	name = devm_kasprintf(dev, GFP_KERNEL, "%s%d", dict->pfx, idx);
1809 done:
1810 	mutex_unlock(&coresight_mutex);
1811 	return name;
1812 }
1813 EXPORT_SYMBOL_GPL(coresight_alloc_device_name);
1814 
1815 struct bus_type coresight_bustype = {
1816 	.name	= "coresight",
1817 };
1818 
1819 static int __init coresight_init(void)
1820 {
1821 	int ret;
1822 
1823 	ret = bus_register(&coresight_bustype);
1824 	if (ret)
1825 		return ret;
1826 
1827 	ret = etm_perf_init();
1828 	if (ret)
1829 		goto exit_bus_unregister;
1830 
1831 	/* initialise the coresight syscfg API */
1832 	ret = cscfg_init();
1833 	if (!ret)
1834 		return 0;
1835 
1836 	etm_perf_exit();
1837 exit_bus_unregister:
1838 	bus_unregister(&coresight_bustype);
1839 	return ret;
1840 }
1841 
1842 static void __exit coresight_exit(void)
1843 {
1844 	cscfg_exit();
1845 	etm_perf_exit();
1846 	bus_unregister(&coresight_bustype);
1847 }
1848 
1849 module_init(coresight_init);
1850 module_exit(coresight_exit);
1851 
1852 MODULE_LICENSE("GPL v2");
1853 MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
1854 MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
1855 MODULE_DESCRIPTION("Arm CoreSight tracer driver");
1856