source: trunk/kernel/libk/remote_buf.h @ 671

Last change on this file since 671 was 671, checked in by alain, 3 years ago

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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 * This kernel buffer is implementes as an array of bytes. The size must be a power
35 * of 2, dynamically defined by an argument of the "remote_buf_init()" function.
36 * The "put()" and "get()" functions defined below move the content of another
37 * buffer (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 the hal_remote_atomic_add() primitive.
40 *
41 * - It is used to implement the three socket buffers (rx_buf / r2tq / crqq).
42 * - It is also used to implement the inter-process communications channels
43 *   based on named "fifos", or unamed "pipes".
44 ***********************************************************************************/
45
46typedef struct remote_buf_s
47{
48    uint32_t   order;   /*! ln2( size of data buffer in bytes)                     */
49        uint32_t   rid;     /*! first empty slot index                                 */
50        uint32_t   wid;     /*! 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 allocates memory for a remote_buf descriptor in cluster
58 * defined by the <cxy> argument, and return a local pointer on this descriptor.
59 ************************************************************************************
60 * @ cxy    : target cluster identifier.
61 * @ return local pointer on remote_buf descriptor.
62 ***********************************************************************************/
63remote_buf_t * remote_buf_alloc( cxy_t  cxy );
64
65/************************************************************************************
66 * This function initializes a remote_buf descriptor identified by the <buf_xp>
67 * argument. It allocates memory for the data, as defined by the <order> argument,
68 * and initializes the buffer as empty. It must be called by a local thread.
69 * The <order> value cannot be larger than 31.
70 ************************************************************************************
71 * @ buf_xp    : [in] extended pointer on buffer descriptor.
72 * @ order     : [in] ln2( number of bytes in buffer) / must be in [0,31].
73 * @ return  0 if success / return -1 if memory failure or illegal order.
74 ***********************************************************************************/
75error_t remote_buf_init( xptr_t   buf_xp,
76                         uint32_t order );
77
78/************************************************************************************
79 * This function releases memory allocated for the data buffer of an embedded
80 * remote-buf descriptor identified by the <buf_xp> argument, when the "data"
81 * pointer is not NULL. It does nothing if the data buffer was not allocated.
82 * WARNING : do NOT use this function for a dynamically allocated remote_buf.
83 ************************************************************************************
84 * @ buf_xp      : [in] extended pointer on buffer descriptor.
85 ***********************************************************************************/
86void remote_buf_release_data( xptr_t buf_xp );
87
88/************************************************************************************
89 * This function releases both the memory allocated for the data buffer, and the
90 * memory allocated for the remote_buf descriptor, for a remote-buf identified
91 * by the <buf_xp> argument.
92 * WARNING : do NOT use this function an embedded remote_buf.
93 ************************************************************************************
94 * @ buf_xp      : [in] extended pointer on buffer descriptor.
95 ***********************************************************************************/
96void remote_buf_destroy( xptr_t buf_xp );
97
98/************************************************************************************
99 * This function initialises as empty a buffer identified by the <buf_xp> argument.
100 * It can be called by a thread runing in any cluster.
101 ************************************************************************************
102 * @ buf_xp    : [in] extended pointer on remote buffer descriptor.
103 ***********************************************************************************/
104void remote_buf_reset( xptr_t buf_xp );
105
106/************************************************************************************
107 * This function moves <nbytes> from a remote_buf_t identified by the <buf_xp>
108 * argument to an user buffer identified by the <u_buf> argument.
109 * It uses the hal_copy_to_uspace() function, and updates "sts" and "ptr".
110 * The calling function is supposed to previously check the buffer status.
111 * It can be called by a thread runing in any cluster.
112 ************************************************************************************
113 * @ buf_xp    : [in] extended pointer pointer on remote buffer descriptor.
114 * @ u_buf     : [in] pointer on destination user buffer in user space.
115 * @ nbytes    : [in] number of bytes to move.
116 * @ return 0 if success / return -1 if not enough bytes in buffer.
117 ***********************************************************************************/
118error_t remote_buf_get_to_user( xptr_t    buf_xp,
119                                uint8_t * u_buf,
120                                uint32_t  nbytes );
121
122/************************************************************************************
123 * This function moves <nbytes> from a remote_buf_t identified by the <buf_xp>
124 * argument to a local kernel buffer identified by the <k_buf> argument.
125 * It uses an hal_remote_memcpy() function, and updates the "sts" and "ptr" fields.
126 * The calling function is supposed to previously check the buffer status.
127 * It can be called by a thread runing in any cluster.
128 ************************************************************************************
129 * @ buf_xp    : [in] extended pointer pointer on remote buffer descriptor.
130 * @ k_buf     : [in] local pointer on local destination kernel buffer.
131 * @ nbytes    : [in] number of bytes to move.
132 * @ return 0 if success / return -1 if not enough bytes in buffer.
133 ***********************************************************************************/
134error_t remote_buf_get_to_kernel( xptr_t    buf_xp,
135                                  uint8_t * k_buf,
136                                  uint32_t  nbytes );
137
138/************************************************************************************
139 * This function moves <nbytes> from an user buffer identified by the <u_buf>
140 * argument to a remote_buf_t identified by the <buf_xp> argument.
141 * It uses the hal_copy_from_uspace() function, and updates "sts" and "ptw"..
142 * The calling function is supposed to previously check the buffer status.
143 * It can be called by a thread runing in any cluster.
144 ************************************************************************************
145 * @ buf_xp    : [in] extended pointer pointer on remote buffer descriptor.
146 * @ u_buf     : [in] pointer on source user buffer in user space.
147 * @ nbytes    : [in] number of bytes to move.
148 * @ return 0 if success / return -1 if not enough bytes in buffer.
149 ***********************************************************************************/
150error_t remote_buf_put_from_user( xptr_t    buf_xp,
151                                  uint8_t * u_buf,
152                                  uint32_t  nbytes );
153
154/************************************************************************************
155 * This function moves <nbytes> from a local kernel buffer identified by the <k_buf>
156 * argument to a remote_buf_t identified by the <buf_xp> argument.
157 * It uses an hal_remote_memcpy() function, and updates the "sts" and "ptw" fields.
158 * The calling function is supposed to previously check the buffer status.
159 * It can be called by a thread runing in any cluster.
160 ************************************************************************************
161 * @ buf_xp    : [in] extended pointer pointer on remote buffer descriptor.
162 * @ k_buf     : [in] local pointer on local source kernel buffer.
163 * @ nbytes    : [in] number of bytes to move.
164 * @ return 0 if success / return -1 if not enough bytes in buffer.
165 ***********************************************************************************/
166error_t remote_buf_put_from_kernel( xptr_t    buf_xp,
167                                    uint8_t * k_buf,
168                                    uint32_t  nbytes );
169
170/************************************************************************************
171 * This function returns the current number of bytes stored in buffer.
172 ************************************************************************************
173 * @ buf_xp    : [in] extended pointer pointer on remote buffer descriptor.
174 * @ return current number of bytes in buffer.
175 ***********************************************************************************/
176uint32_t remote_buf_status( xptr_t  buf_xp );
177
178#endif  /* _REMOTE_BUFFER_H_ */
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