source: trunk/kernel/libk/remote_buf.h @ 662

Last change on this file since 662 was 657, checked in by alain, 5 years ago

Introduce remote_buf.c/.h & socket.c/.h files.
Update dev_nic.c/.h files.
File size: 8.8 KB
Line 
1/*
2 * remote_buf.h -  Remotely accessible, circular buffer definition.
3 *
4 * Authors :
5 *           Alain Greiner (2016,2017,2018,2019,2020)
6 *
7 * Copyright (c) UPMC Sorbonne Universites
8 *
9 * This file is part of ALMOS-MKH.
10 *
11 * ALMOS-MHH is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; version 2.0 of the License.
14 *
15 * ALMOS-MKH is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
22 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25#ifndef _REMOTE_BUFFER_H_
26#define _REMOTE_BUFFER_H_
27
28#include <kernel_config.h>
29#include <hal_kernel_types.h>
30
31/************************************************************************************
32 * This structure and the associated access functions define a remotely accessible,
33 * kernel buffer, handled as a single-reader & single-writer FIFO.
34 * Each buffer slot contains one byte, and the number of slots is dynamically
35 * defined by an argument of the "remote_buf_create()" function.
36 * The "put()" and "get()" access functions defined below move another buffer,
37 * (can be in kernel or in user space) to/from this circular kernel buffer.
38 * This structure is NOT protected by a lock, as the only shared variable is the
39 * "sts" variable, that is updated by hal_remote_atomic_add() access primitives.
40 * It is used by to implement the socket receive buffer.
41 * - the "ptw" field defines the first empty slot (for write).
42 * - the "ptr" field defines the first non empty slot (for read).
43 * - the "sts" field defines the total number of non empty slots.
44 ***********************************************************************************/
45
46typedef struct remote_buf_s
47{
48    uint32_t   size;    /*! number of slots in data buffer                         */
49        uint32_t   ptw;     /*! first empty slot index                                 */
50        uint32_t   ptr;     /*! first non-empty slot index                             */
51    uint32_t   sts;     /*! current number of non empty slots                      */
52        uint8_t  * data;    /*! local pointer on local data buffer                     */
53}
54remote_buf_t;
55
56/************************************************************************************
57 * This function initializes a remote_buf descriptor identified by the <buf_xp>
58 * argument. It allocates memory for the data, as defined by the <size> argument,
59 * and initializes the buffer as empty. It must be called by a local thread.
60 ************************************************************************************
61 * @ buf_xp    : [in] extended pointer on buffer descriptor.
62 * @ size      : [in] number of bytes in buffer.
63 * @ return  0 if success / return -1 if failure (no memory).
64 ***********************************************************************************/
65error_t remote_buf_create( xptr_t   buf_xp,
66                           uint32_t size );
67
68/************************************************************************************
69 * This function releases memory allocated for the data buffer of a remote-buf
70 * descriptor identified by the <buf_xp> argument.
71 * It must be called by a local thread.
72 ************************************************************************************
73 * @ buf_xp      : [in] extended pointer on buffer descriptor.
74 ***********************************************************************************/
75void remote_buf_destroy( xptr_t buf_xp );
76
77/************************************************************************************
78 * This function initialises as empty a buffer identified by the <buf_xp> argument.
79 * It can be called by a thread runing in any cluster.
80 ************************************************************************************
81 * @ buf_xp    : [in] extended pointer on remote buffer descriptor.
82 ***********************************************************************************/
83void remote_buf_reset( xptr_t buf_xp );
84
85/************************************************************************************
86 * This function moves <nbytes> from a remote_buf_t identified by the <buf_xp>
87 * argument to an user buffer identified by the <u_buf> argument.
88 * It uses the hal_copy_to_uspace() function, and updates "sts" and "ptr".
89 * The calling function is supposed to previously check the buffer status.
90 * It can be called by a thread runing in any cluster.
91 ************************************************************************************
92 * @ buf_xp    : [in] extended pointer pointer on remote buffer descriptor.
93 * @ u_buf     : [in] pointer on destination user buffer in user space.
94 * @ nbytes    : [in] number of bytes to move.
95 * @ return 0 if success / return -1 if not enough bytes in buffer.
96 ***********************************************************************************/
97error_t remote_buf_get_to_user( xptr_t    buf_xp,
98                                uint8_t * u_buf,
99                                uint32_t  nbytes );
100
101/************************************************************************************
102 * This function moves <nbytes> from a remote_buf_t identified by the <buf_xp>
103 * argument to a local kernel buffer identified by the <k_buf> argument.
104 * It uses an hal_remote_memcpy() function, and updates the "sts" and "ptr" fields.
105 * The calling function is supposed to previously check the buffer status.
106 * It can be called by a thread runing in any cluster.
107 ************************************************************************************
108 * @ buf_xp    : [in] extended pointer pointer on remote buffer descriptor.
109 * @ k_buf     : [in] local pointer on local destination kernel buffer.
110 * @ nbytes    : [in] number of bytes to move.
111 * @ return 0 if success / return -1 if not enough bytes in buffer.
112 ***********************************************************************************/
113error_t remote_buf_get_to_kernel( xptr_t    buf_xp,
114                                  uint8_t * k_buf,
115                                  uint32_t  nbytes );
116
117/************************************************************************************
118 * This function moves <nbytes> from an user buffer identified by the <u_buf>
119 * argument to a remote_buf_t identified by the <buf_xp> argument.
120 * It uses the hal_copy_from_uspace() function, and updates "sts" and "ptw"..
121 * The calling function is supposed to previously check the buffer status.
122 * It can be called by a thread runing in any cluster.
123 ************************************************************************************
124 * @ buf_xp    : [in] extended pointer pointer on remote buffer descriptor.
125 * @ u_buf     : [in] pointer on source user buffer in user space.
126 * @ nbytes    : [in] number of bytes to move.
127 * @ return 0 if success / return -1 if not enough bytes in buffer.
128 ***********************************************************************************/
129error_t remote_buf_put_from_user( xptr_t    buf_xp,
130                                  uint8_t * u_buf,
131                                  uint32_t  nbytes );
132
133/************************************************************************************
134 * This function moves <nbytes> from a local kernel buffer identified by the <k_buf>
135 * argument to a remote_buf_t identified by the <buf_xp> argument.
136 * It uses an hal_remote_memcpy() function, and updates the "sts" and "ptw" fields.
137 * The calling function is supposed to previously check the buffer status.
138 * It can be called by a thread runing in any cluster.
139 ************************************************************************************
140 * @ buf_xp    : [in] extended pointer pointer on remote buffer descriptor.
141 * @ k_buf     : [in] local pointer on local source kernel buffer.
142 * @ nbytes    : [in] number of bytes to move.
143 * @ return 0 if success / return -1 if not enough bytes in buffer.
144 ***********************************************************************************/
145error_t remote_buf_put_from_kernel( xptr_t    buf_xp,
146                                    uint8_t * k_buf,
147                                    uint32_t  nbytes );
148
149/************************************************************************************
150 * This function returns the current number of bytes stored in buffer.
151 ************************************************************************************
152 * @ buf_xp    : [in] extended pointer pointer on remote buffer descriptor.
153 * @ return current number of bytes in buffer.
154 ***********************************************************************************/
155uint32_t remote_buf_status( xptr_t  buf_xp );
156
157#endif  /* _REMOTE_BUFFER_H_ */
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