1/*
2 * Copyright (c) 2013-2019, Intel Corporation
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 *  * Redistributions of source code must retain the above copyright notice,
8 *    this list of conditions and the following disclaimer.
9 *  * Redistributions in binary form must reproduce the above copyright notice,
10 *    this list of conditions and the following disclaimer in the documentation
11 *    and/or other materials provided with the distribution.
12 *  * Neither the name of Intel Corporation nor the names of its contributors
13 *    may be used to endorse or promote products derived from this software
14 *    without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include "pt_event_queue.h"
30
31#include <string.h>
32
33
34static inline uint8_t pt_evq_inc(uint8_t idx)
35{
36	idx += 1;
37	idx %= evq_max;
38
39	return idx;
40}
41
42static struct pt_event *pt_event_init(struct pt_event *event)
43{
44	if (event)
45		memset(event, 0, sizeof(*event));
46
47	return event;
48}
49
50void pt_evq_init(struct pt_event_queue *evq)
51{
52	if (!evq)
53		return;
54
55	memset(evq, 0, sizeof(*evq));
56}
57
58struct pt_event *pt_evq_standalone(struct pt_event_queue *evq)
59{
60	if (!evq)
61		return NULL;
62
63	return pt_event_init(&evq->standalone);
64}
65
66struct pt_event *pt_evq_enqueue(struct pt_event_queue *evq,
67				enum pt_event_binding evb)
68{
69	uint8_t begin, end, gap, idx;
70
71	if (!evq)
72		return NULL;
73
74	if (evb_max <= evb)
75		return NULL;
76
77	begin = evq->begin[evb];
78	idx = evq->end[evb];
79
80	if (evq_max <= begin)
81		return NULL;
82
83	if (evq_max <= idx)
84		return NULL;
85
86	end = pt_evq_inc(idx);
87	gap = pt_evq_inc(end);
88
89	/* Leave a gap so we don't overwrite the last dequeued event. */
90	if (begin == gap)
91		return NULL;
92
93	evq->end[evb] = end;
94
95	return pt_event_init(&evq->queue[evb][idx]);
96}
97
98struct pt_event *pt_evq_dequeue(struct pt_event_queue *evq,
99				enum pt_event_binding evb)
100{
101	uint8_t begin, end;
102
103	if (!evq)
104		return NULL;
105
106	if (evb_max <= evb)
107		return NULL;
108
109	begin = evq->begin[evb];
110	end = evq->end[evb];
111
112	if (evq_max <= begin)
113		return NULL;
114
115	if (evq_max <= end)
116		return NULL;
117
118	if (begin == end)
119		return NULL;
120
121	evq->begin[evb] = pt_evq_inc(begin);
122
123	return &evq->queue[evb][begin];
124}
125
126int pt_evq_clear(struct pt_event_queue *evq, enum pt_event_binding evb)
127{
128	if (!evq)
129		return -pte_internal;
130
131	if (evb_max <= evb)
132		return -pte_internal;
133
134	evq->begin[evb] = 0;
135	evq->end[evb] = 0;
136
137	return 0;
138}
139
140int pt_evq_empty(const struct pt_event_queue *evq, enum pt_event_binding evb)
141{
142	uint8_t begin, end;
143
144	if (!evq)
145		return -pte_internal;
146
147	if (evb_max <= evb)
148		return -pte_internal;
149
150	begin = evq->begin[evb];
151	end = evq->end[evb];
152
153	if (evq_max <= begin)
154		return -pte_internal;
155
156	if (evq_max <= end)
157		return -pte_internal;
158
159	return begin == end;
160}
161
162int pt_evq_pending(const struct pt_event_queue *evq, enum pt_event_binding evb)
163{
164	int errcode;
165
166	errcode = pt_evq_empty(evq, evb);
167	if (errcode < 0)
168		return errcode;
169
170	return !errcode;
171}
172
173struct pt_event *pt_evq_find(struct pt_event_queue *evq,
174			     enum pt_event_binding evb,
175			     enum pt_event_type evt)
176{
177	uint8_t begin, end;
178
179	if (!evq)
180		return NULL;
181
182	if (evb_max <= evb)
183		return NULL;
184
185	begin = evq->begin[evb];
186	end = evq->end[evb];
187
188	if (evq_max <= begin)
189		return NULL;
190
191	if (evq_max <= end)
192		return NULL;
193
194	for (; begin != end; begin = pt_evq_inc(begin)) {
195		struct pt_event *ev;
196
197		ev = &evq->queue[evb][begin];
198		if (ev->type == evt)
199			return ev;
200	}
201
202	return NULL;
203}
204