1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
|
/****************************************************************************
* include/nuttx/rwbuffer.h
*
* Copyright (C) 2009, 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef __INCLUDE_NUTTX_RWBUFFER_H
#define __INCLUDE_NUTTX_RWBUFFER_H
/**********************************************************************
* Included Files
**********************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <semaphore.h>
#include <nuttx/wqueue.h>
#if defined(CONFIG_DRVR_WRITEBUFFER) || defined(CONFIG_DRVR_READAHEAD)
/**********************************************************************
* Pre-processor Definitions
**********************************************************************/
/**********************************************************************
* Public Types
**********************************************************************/
/* Data transfer callouts. These must be provided by the block driver
* logic in order to flush the write buffer when appropriate or to
* reload the read-ahead buffer, when appropriate.
*/
typedef ssize_t (*rwbreload_t)(FAR void *dev, FAR uint8_t *buffer,
off_t startblock, size_t nblocks);
typedef ssize_t (*rwbflush_t)(FAR void *dev, FAR const uint8_t *buffer,
off_t startblock, size_t nblocks);
/* This structure holds the state of the buffers. In typical usage,
* an instance of this structure is declared within each block driver
* status structure like:
*
* struct foo_dev_s
* {
* ...
* struct rwbuffer_s rwbuffer;
* ...
* };
*
* Note that this supports buffering for multiple block devices or for
* multiple instances of same block device, because each rwbuffer instance
* supports independent buffering.
*
* A reference to the struct rwbuffer_s instance is then passed to each
* interface like:
*
* struct foo_dev_s *priv;
* ...
* ... [Setup blocksize, nblocks, dev, wrmaxblocks, wrflush,
* rhmaxblocks, rhreload] ...
* ret = rwb_initialize(&priv->rwbuffer);
*/
struct rwbuffer_s
{
/********************************************************************/
/* These values must be provided by the user prior to calling
* rwb_initialize()
*/
/* Supported geometry */
uint16_t blocksize; /* The size of one block */
size_t nblocks; /* The total number blocks supported */
/* Read-ahead/Write buffer sizes. Buffering can be disabled (even if it
* is enabled in the configuration) by setting the buffer size to zero
* blocks.
*/
#ifdef CONFIG_DRVR_WRITEBUFFER
uint16_t wrmaxblocks; /* The number of blocks to buffer in memory */
#endif
#ifdef CONFIG_DRVR_READAHEAD
uint16_t rhmaxblocks; /* The number of blocks to buffer in memory */
#endif
/* Callback functions.
*
* wrflush. This callback is normally used to flush the contents of
* the write buffer. If write buffering is disabled, then this
* function will instead be used to perform unbuffered writes.
* rhrelad. This callback is normally used to read new data into the
* read-ahead buffer. If read-ahead buffering is disabled, then this
* function will instead be used to perform unbuffered reads.
*/
FAR void *dev; /* Device state passed to callout functions */
rwbflush_t wrflush; /* Callout to flush the write buffer */
rwbreload_t rhreload; /* Callout to reload the read-ahead buffer */
/********************************************************************/
/* The user should never modify any of the remaining fields */
/* This is the state of the write buffering */
#ifdef CONFIG_DRVR_WRITEBUFFER
sem_t wrsem; /* Enforces exclusive access to the write buffer */
struct work_s work; /* Delayed work to flush buffer after a delay with no activity */
uint8_t *wrbuffer; /* Allocated write buffer */
uint16_t wrnblocks; /* Number of blocks in write buffer */
off_t wrblockstart; /* First block in write buffer */
off_t wrexpectedblock; /* Next block expected */
#endif
/* This is the state of the read-ahead buffering */
#ifdef CONFIG_DRVR_READAHEAD
sem_t rhsem; /* Enforces exclusive access to the write buffer */
uint8_t *rhbuffer; /* Allocated read-ahead buffer */
uint16_t rhnblocks; /* Number of blocks in read-ahead buffer */
off_t rhblockstart; /* First block in read-ahead buffer */
#endif
};
/**********************************************************************
* Global Variables
**********************************************************************/
#undef EXTERN
#if defined(__cplusplus)
#define EXTERN EXTERN "C"
EXTERN "C"
{
#else
#define EXTERN extern
#endif
/**********************************************************************
* Global Function Prototypes
**********************************************************************/
/* Buffer initialization */
int rwb_initialize(FAR struct rwbuffer_s *rwb);
void rwb_uninitialize(FAR struct rwbuffer_s *rwb);
/* Block oriented transfers */
ssize_t rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock,
size_t blockcount, FAR uint8_t *rdbuffer);
ssize_t rwb_write(FAR struct rwbuffer_s *rwb,
off_t startblock, size_t blockcount,
FAR const uint8_t *wrbuffer);
/* Character oriented transfers */
#ifdef CONFIG_DRVR_READBYTES
ssize_t rwb_readbytes(FAR struct rwbuffer_s *dev, off_t offset,
size_t nbytes, FAR uint8_t *buffer);
#endif
/* Media events */
#ifdef CONFIG_DRVR_REMOVABLE
int rwb_mediaremoved(FAR struct rwbuffer_s *rwb);
#endif
#ifdef CONFIG_DRVR_INVALIDATE
int rwb_invalidate(FAR struct rwbuffer_s *rwb,
off_t startblock, size_t blockcount);
#endif
#undef EXTERN
#if defined(__cplusplus)
}
#endif
#endif /* CONFIG_DRVR_WRITEBUFFER || CONFIG_DRVR_READAHEAD */
#endif /* __INCLUDE_NUTTX_RWBUFFER_H */
|
