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
30static DEFINE_MUTEX(coresight_mutex);
31
32static 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
59static 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
71static 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
92static 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
113static 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
131static 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
141static 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
171static 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
204static 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
228static 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
238static 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;
262err:
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
277static 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
299static 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 ||
309	    csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
310	    csdev->activated) {
311		if (enable)
312			ret = coresight_enable_path(path);
313		else
314			ret = coresight_disable_path(path);
315	} else {
316		for (i = 0; i < csdev->nr_outport; i++) {
317			conn = &csdev->conns[i];
318			if (coresight_build_paths(conn->child_dev,
319						    path, enable) == 0)
320				ret = 0;
321		}
322	}
323
324	if (list_first_entry(path, struct coresight_device, path_link) != csdev)
325		dev_err(&csdev->dev, "wrong device in %s\n", __func__);
326
327	list_del(&csdev->path_link);
328
329	return ret;
330}
331
332int coresight_enable(struct coresight_device *csdev)
333{
334	int ret = 0;
335	LIST_HEAD(path);
336
337	mutex_lock(&coresight_mutex);
338	if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) {
339		ret = -EINVAL;
340		dev_err(&csdev->dev, "wrong device type in %s\n", __func__);
341		goto out;
342	}
343	if (csdev->enable)
344		goto out;
345
346	if (coresight_build_paths(csdev, &path, true)) {
347		dev_err(&csdev->dev, "building path(s) failed\n");
348		goto out;
349	}
350
351	if (coresight_enable_source(csdev))
352		dev_err(&csdev->dev, "source enable failed\n");
353out:
354	mutex_unlock(&coresight_mutex);
355	return ret;
356}
357EXPORT_SYMBOL_GPL(coresight_enable);
358
359void coresight_disable(struct coresight_device *csdev)
360{
361	LIST_HEAD(path);
362
363	mutex_lock(&coresight_mutex);
364	if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) {
365		dev_err(&csdev->dev, "wrong device type in %s\n", __func__);
366		goto out;
367	}
368	if (!csdev->enable)
369		goto out;
370
371	coresight_disable_source(csdev);
372	if (coresight_build_paths(csdev, &path, false))
373		dev_err(&csdev->dev, "releasing path(s) failed\n");
374
375out:
376	mutex_unlock(&coresight_mutex);
377}
378EXPORT_SYMBOL_GPL(coresight_disable);
379
380static ssize_t enable_sink_show(struct device *dev,
381				struct device_attribute *attr, char *buf)
382{
383	struct coresight_device *csdev = to_coresight_device(dev);
384
385	return scnprintf(buf, PAGE_SIZE, "%u\n", (unsigned)csdev->activated);
386}
387
388static ssize_t enable_sink_store(struct device *dev,
389				 struct device_attribute *attr,
390				 const char *buf, size_t size)
391{
392	int ret;
393	unsigned long val;
394	struct coresight_device *csdev = to_coresight_device(dev);
395
396	ret = kstrtoul(buf, 10, &val);
397	if (ret)
398		return ret;
399
400	if (val)
401		csdev->activated = true;
402	else
403		csdev->activated = false;
404
405	return size;
406
407}
408static DEVICE_ATTR_RW(enable_sink);
409
410static ssize_t enable_source_show(struct device *dev,
411				  struct device_attribute *attr, char *buf)
412{
413	struct coresight_device *csdev = to_coresight_device(dev);
414
415	return scnprintf(buf, PAGE_SIZE, "%u\n", (unsigned)csdev->enable);
416}
417
418static ssize_t enable_source_store(struct device *dev,
419				   struct device_attribute *attr,
420				   const char *buf, size_t size)
421{
422	int ret = 0;
423	unsigned long val;
424	struct coresight_device *csdev = to_coresight_device(dev);
425
426	ret = kstrtoul(buf, 10, &val);
427	if (ret)
428		return ret;
429
430	if (val) {
431		ret = coresight_enable(csdev);
432		if (ret)
433			return ret;
434	} else {
435		coresight_disable(csdev);
436	}
437
438	return size;
439}
440static DEVICE_ATTR_RW(enable_source);
441
442static struct attribute *coresight_sink_attrs[] = {
443	&dev_attr_enable_sink.attr,
444	NULL,
445};
446ATTRIBUTE_GROUPS(coresight_sink);
447
448static struct attribute *coresight_source_attrs[] = {
449	&dev_attr_enable_source.attr,
450	NULL,
451};
452ATTRIBUTE_GROUPS(coresight_source);
453
454static struct device_type coresight_dev_type[] = {
455	{
456		.name = "none",
457	},
458	{
459		.name = "sink",
460		.groups = coresight_sink_groups,
461	},
462	{
463		.name = "link",
464	},
465	{
466		.name = "linksink",
467		.groups = coresight_sink_groups,
468	},
469	{
470		.name = "source",
471		.groups = coresight_source_groups,
472	},
473};
474
475static void coresight_device_release(struct device *dev)
476{
477	struct coresight_device *csdev = to_coresight_device(dev);
478
479	kfree(csdev);
480}
481
482static int coresight_orphan_match(struct device *dev, void *data)
483{
484	int i;
485	bool still_orphan = false;
486	struct coresight_device *csdev, *i_csdev;
487	struct coresight_connection *conn;
488
489	csdev = data;
490	i_csdev = to_coresight_device(dev);
491
492	/* No need to check oneself */
493	if (csdev == i_csdev)
494		return 0;
495
496	/* Move on to another component if no connection is orphan */
497	if (!i_csdev->orphan)
498		return 0;
499	/*
500	 * Circle throuch all the connection of that component.  If we find
501	 * an orphan connection whose name matches @csdev, link it.
502	 */
503	for (i = 0; i < i_csdev->nr_outport; i++) {
504		conn = &i_csdev->conns[i];
505
506		/* We have found at least one orphan connection */
507		if (conn->child_dev == NULL) {
508			/* Does it match this newly added device? */
509			if (!strcmp(dev_name(&csdev->dev), conn->child_name)) {
510				conn->child_dev = csdev;
511			} else {
512				/* This component still has an orphan */
513				still_orphan = true;
514			}
515		}
516	}
517
518	i_csdev->orphan = still_orphan;
519
520	/*
521	 * Returning '0' ensures that all known component on the
522	 * bus will be checked.
523	 */
524	return 0;
525}
526
527static void coresight_fixup_orphan_conns(struct coresight_device *csdev)
528{
529	/*
530	 * No need to check for a return value as orphan connection(s)
531	 * are hooked-up with each newly added component.
532	 */
533	bus_for_each_dev(&coresight_bustype, NULL,
534				 csdev, coresight_orphan_match);
535}
536
537
538static int coresight_name_match(struct device *dev, void *data)
539{
540	char *to_match;
541	struct coresight_device *i_csdev;
542
543	to_match = data;
544	i_csdev = to_coresight_device(dev);
545
546	if (to_match && !strcmp(to_match, dev_name(&i_csdev->dev)))
547		return 1;
548
549	return 0;
550}
551
552static void coresight_fixup_device_conns(struct coresight_device *csdev)
553{
554	int i;
555	struct device *dev = NULL;
556	struct coresight_connection *conn;
557
558	for (i = 0; i < csdev->nr_outport; i++) {
559		conn = &csdev->conns[i];
560		dev = bus_find_device(&coresight_bustype, NULL,
561				      (void *)conn->child_name,
562				      coresight_name_match);
563
564		if (dev) {
565			conn->child_dev = to_coresight_device(dev);
566		} else {
567			csdev->orphan = true;
568			conn->child_dev = NULL;
569		}
570	}
571}
572
573/**
574 * coresight_timeout - loop until a bit has changed to a specific state.
575 * @addr: base address of the area of interest.
576 * @offset: address of a register, starting from @addr.
577 * @position: the position of the bit of interest.
578 * @value: the value the bit should have.
579 *
580 * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
581 * TIMEOUT_US has elapsed, which ever happens first.
582 */
583
584int coresight_timeout(void __iomem *addr, u32 offset, int position, int value)
585{
586	int i;
587	u32 val;
588
589	for (i = TIMEOUT_US; i > 0; i--) {
590		val = __raw_readl(addr + offset);
591		/* waiting on the bit to go from 0 to 1 */
592		if (value) {
593			if (val & BIT(position))
594				return 0;
595		/* waiting on the bit to go from 1 to 0 */
596		} else {
597			if (!(val & BIT(position)))
598				return 0;
599		}
600
601		/*
602		 * Delay is arbitrary - the specification doesn't say how long
603		 * we are expected to wait.  Extra check required to make sure
604		 * we don't wait needlessly on the last iteration.
605		 */
606		if (i - 1)
607			udelay(1);
608	}
609
610	return -EAGAIN;
611}
612
613struct bus_type coresight_bustype = {
614	.name	= "coresight",
615};
616
617static int __init coresight_init(void)
618{
619	return bus_register(&coresight_bustype);
620}
621postcore_initcall(coresight_init);
622
623struct coresight_device *coresight_register(struct coresight_desc *desc)
624{
625	int i;
626	int ret;
627	int link_subtype;
628	int nr_refcnts = 1;
629	atomic_t *refcnts = NULL;
630	struct coresight_device *csdev;
631	struct coresight_connection *conns;
632
633	csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
634	if (!csdev) {
635		ret = -ENOMEM;
636		goto err_kzalloc_csdev;
637	}
638
639	if (desc->type == CORESIGHT_DEV_TYPE_LINK ||
640	    desc->type == CORESIGHT_DEV_TYPE_LINKSINK) {
641		link_subtype = desc->subtype.link_subtype;
642
643		if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
644			nr_refcnts = desc->pdata->nr_inport;
645		else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
646			nr_refcnts = desc->pdata->nr_outport;
647	}
648
649	refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
650	if (!refcnts) {
651		ret = -ENOMEM;
652		goto err_kzalloc_refcnts;
653	}
654
655	csdev->refcnt = refcnts;
656
657	csdev->nr_inport = desc->pdata->nr_inport;
658	csdev->nr_outport = desc->pdata->nr_outport;
659	conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
660	if (!conns) {
661		ret = -ENOMEM;
662		goto err_kzalloc_conns;
663	}
664
665	for (i = 0; i < csdev->nr_outport; i++) {
666		conns[i].outport = desc->pdata->outports[i];
667		conns[i].child_name = desc->pdata->child_names[i];
668		conns[i].child_port = desc->pdata->child_ports[i];
669	}
670
671	csdev->conns = conns;
672
673	csdev->type = desc->type;
674	csdev->subtype = desc->subtype;
675	csdev->ops = desc->ops;
676	csdev->orphan = false;
677
678	csdev->dev.type = &coresight_dev_type[desc->type];
679	csdev->dev.groups = desc->groups;
680	csdev->dev.parent = desc->dev;
681	csdev->dev.release = coresight_device_release;
682	csdev->dev.bus = &coresight_bustype;
683	dev_set_name(&csdev->dev, "%s", desc->pdata->name);
684
685	ret = device_register(&csdev->dev);
686	if (ret)
687		goto err_device_register;
688
689	mutex_lock(&coresight_mutex);
690
691	coresight_fixup_device_conns(csdev);
692	coresight_fixup_orphan_conns(csdev);
693
694	mutex_unlock(&coresight_mutex);
695
696	return csdev;
697
698err_device_register:
699	kfree(conns);
700err_kzalloc_conns:
701	kfree(refcnts);
702err_kzalloc_refcnts:
703	kfree(csdev);
704err_kzalloc_csdev:
705	return ERR_PTR(ret);
706}
707EXPORT_SYMBOL_GPL(coresight_register);
708
709void coresight_unregister(struct coresight_device *csdev)
710{
711	mutex_lock(&coresight_mutex);
712
713	kfree(csdev->conns);
714	device_unregister(&csdev->dev);
715
716	mutex_unlock(&coresight_mutex);
717}
718EXPORT_SYMBOL_GPL(coresight_unregister);
719
720MODULE_LICENSE("GPL v2");
721