1 /*
2 * Copyright (c) 2019, Nordic Semiconductor ASA
3 * All rights reserved.
4 *
5 * SPDX-License-Identifier: BSD-3-Clause
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright notice, this
11 * list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
18 * contributors may be used to endorse or promote products derived from this
19 * software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY, AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
25 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 *
33 */
34
35 /**
36 * @brief Module implementing simple FIFO queue.
37 */
38
39 #ifndef NRF_802154_QUEUE_H__
40 #define NRF_802154_QUEUE_H__
41
42 #include <stdbool.h>
43 #include <stdint.h>
44 #include <stddef.h>
45
46 /**@brief Type representing a FIFO queue. */
47 typedef struct
48 {
49 /**@brief Pointer to items memory of the queue.
50 * @details Memory pointed by this pointer has size @c item_size * @c capacity. */
51 void * p_memory;
52
53 /**@brief Size of an item in the queue. */
54 uint8_t item_size;
55
56 /**@brief Maximum number of items that can be stored in the memory of the queue */
57 uint8_t capacity;
58
59 /**@brief Index in the items memory of the queue where next item is written. */
60 volatile uint8_t wridx;
61
62 /**@brief Index in the items memory of the queue where next item is read. */
63 volatile uint8_t rdidx;
64 } nrf_802154_queue_t;
65
66 /**@brief Initializes a queue.
67 *
68 * @param[in] p_queue Pointer to the queue instance to be initialized. Must not be NULL.
69 * @param[in] p_memory Pointer to a memory that will be used to store items of the queue.
70 * Must not be NULL.
71 * @param[in] memory_size Size of the memory pointed by @p p_memory.
72 * This parameter must be no less than 2 * @p item_size
73 * @param[in] item_size Size of an item of the queue. Must not be 0.
74 */
75 void nrf_802154_queue_init(nrf_802154_queue_t * p_queue,
76 void * p_memory,
77 size_t memory_size,
78 size_t item_size);
79
80 /**@brief Returns pointer to the next item to be written to the queue.
81 *
82 * This function is to be used when writing data to the queue directly (no copy).
83 * Returned pointer is valid when the queue is not full (@ref nrf_802154_queue_is_full returned false).
84 * To write an item to the queue perform following.
85 * @code
86 * if (!nrf_802154_queue_is_full(&queue))
87 * {
88 * my_item_t * p_item = (my_item_t *)nrf_802154_queue_push_begin(&queue);
89 * ... p_item is now direct pointer into memory of the queue, fill all data at p_item pointer
90 * p_item->some_field = some_value;
91 * ... fill all data at p_item pointer
92 * nrf_802154_queue_push_commit(&queue)
93 * }
94 * @endcode
95 *
96 * To ensure thread-safety external locking is required.
97 *
98 * @param[in] p_queue Pointer to the queue instance.
99 *
100 * @return Pointer to the next item to be written.
101 */
102 void * nrf_802154_queue_push_begin(const nrf_802154_queue_t * p_queue);
103
104 /**@brief Increments write pointer of the queue.
105 *
106 * @param[in] p_queue Pointer to the queue instance.
107 */
108 void nrf_802154_queue_push_commit(nrf_802154_queue_t * p_queue);
109
110 /**@brief Returns pointer to the next item to be read from the queue.
111 *
112 * This function is to be used when reading data from the queue directly (no copy).
113 * Returned pointer is valid when the queue is not empty (@ref nrf_802154_queue_is_empty returned false).
114 * To ensure thread-safety external locking is required.
115 *
116 * To read an item from the queue perform following.
117 * @code
118 * if (!nrf_802154_queue_is_empty(&queue))
119 * {
120 * my_item_t * p_item = (my_item_t *)nrf_802154_queue_pop_begin(&queue);
121 * ... read & process data pointed by p_item
122 * nrf_802154_queue_pop_commit(&queue)
123 * }
124 * @endcode
125 *
126 *
127 * @param[in] p_queue Pointer to the queue instance.
128 *
129 * @return Pointer to the next item to be written.
130 */
131 void * nrf_802154_queue_pop_begin(const nrf_802154_queue_t * p_queue);
132
133 /**@brief Increments read pointer of the queue.
134 *
135 * @param[in] p_queue Pointer to the queue instance.
136 */
137 void nrf_802154_queue_pop_commit(nrf_802154_queue_t * p_queue);
138
139 /**@brief Checks if the queue is empty.
140 *
141 * @param[in] p_queue Pointer to the queue instance.
142 *
143 * @retval true When the queue is empty
144 * @retval false When the queue is not empty.
145 */
nrf_802154_queue_is_empty(const nrf_802154_queue_t * p_queue)146 static inline bool nrf_802154_queue_is_empty(const nrf_802154_queue_t * p_queue)
147 {
148 return (p_queue->wridx == p_queue->rdidx);
149 }
150
151 /**@brief Checks if the queue is full.
152 *
153 * @param[in] p_queue Pointer to the queue instance.
154 *
155 * @retval true When the queue is full.
156 * @retval false When the queue is not full.
157 */
158 bool nrf_802154_queue_is_full(const nrf_802154_queue_t * p_queue);
159
160 #endif /* NRF_802154_QUEUE_H__ */
161
