1 /*
2  *  Copyright (c) 2016, The OpenThread Authors.
3  *  All rights reserved.
4  *
5  *  Redistribution and use in source and binary forms, with or without
6  *  modification, are permitted provided that the following conditions are met:
7  *  1. Redistributions of source code must retain the above copyright
8  *     notice, this list of conditions and the following disclaimer.
9  *  2. Redistributions in binary form must reproduce the above copyright
10  *     notice, this list of conditions and the following disclaimer in the
11  *     documentation and/or other materials provided with the distribution.
12  *  3. Neither the name of the copyright holder nor the
13  *     names of its contributors may be used to endorse or promote products
14  *     derived from this software 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 HOLDER 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 /**
30  * @file
31  * @brief
32  *   This file includes the platform abstraction for the message pool.
33  */
34 
35 #ifndef OPENTHREAD_PLATFORM_MESSAGEPOOL_H_
36 #define OPENTHREAD_PLATFORM_MESSAGEPOOL_H_
37 
38 #include <stdint.h>
39 
40 #include <openthread/message.h>
41 
42 /**
43  * @addtogroup plat-messagepool
44  *
45  * @brief
46  *   This module includes the platform abstraction for the message pool.
47  *
48  * @{
49  *
50  */
51 
52 #ifdef __cplusplus
53 extern "C" {
54 #endif
55 
56 /**
57  * Represents an OpenThread message buffer.
58  *
59  */
60 typedef struct otMessageBuffer
61 {
62     struct otMessageBuffer *mNext; ///< Pointer to the next buffer.
63 } otMessageBuffer;
64 
65 /**
66  * Initialize the platform implemented message pool.
67  *
68  * Is used when `OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT` is enabled.
69  *
70  * @param[in] aInstance            A pointer to the OpenThread instance.
71  * @param[in] aMinNumFreeBuffers   An uint16 containing the minimum number of free buffers desired by OpenThread.
72  * @param[in] aBufferSize          The size in bytes of a buffer object.
73  *
74  */
75 void otPlatMessagePoolInit(otInstance *aInstance, uint16_t aMinNumFreeBuffers, size_t aBufferSize);
76 
77 /**
78  * Allocate a buffer from the platform managed buffer pool.
79  *
80  * Is used when `OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT` is enabled.
81  *
82  * The returned buffer instance MUST have at least `aBufferSize` bytes (as specified in `otPlatMessagePoolInit()`).
83  *
84  * @param[in] aInstance            A pointer to the OpenThread instance.
85  *
86  * @returns A pointer to the buffer or NULL if no buffers are available.
87  *
88  */
89 otMessageBuffer *otPlatMessagePoolNew(otInstance *aInstance);
90 
91 /**
92  * Is used to free a buffer back to the platform managed buffer pool.
93  *
94  * Is used when `OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT` is enabled.
95  *
96  * @param[in]  aInstance  A pointer to the OpenThread instance.
97  * @param[in]  aBuffer    The buffer to free.
98  *
99  */
100 void otPlatMessagePoolFree(otInstance *aInstance, otMessageBuffer *aBuffer);
101 
102 /**
103  * Get the number of free buffers.
104  *
105  * Is used when `OPENTHREAD_CONFIG_PLATFORM_MESSAGE_MANAGEMENT` is enabled.
106  *
107  * @param[in]  aInstance  A pointer to the OpenThread instance.
108  *
109  * @returns The number of buffers currently free and available to OpenThread.
110  *
111  */
112 uint16_t otPlatMessagePoolNumFreeBuffers(otInstance *aInstance);
113 
114 #ifdef __cplusplus
115 } // extern "C"
116 #endif
117 
118 /**
119  * @}
120  *
121  */
122 
123 #endif // OPENTHREAD_PLATFORM_MESSAGEPOOL_H_
124