Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * | |
3 | * dvb_ringbuffer.h: ring buffer implementation for the dvb driver | |
4 | * | |
5 | * Copyright (C) 2003 Oliver Endriss | |
6 | * Copyright (C) 2004 Andrew de Quincey | |
7 | * | |
8 | * based on code originally found in av7110.c & dvb_ci.c: | |
9 | * Copyright (C) 1999-2003 Ralph Metzler & Marcus Metzler | |
10 | * for convergence integrated media GmbH | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU Lesser General Public License | |
14 | * as published by the Free Software Foundation; either version 2.1 | |
15 | * of the License, or (at your option) any later version. | |
16 | * | |
17 | * This program is distributed in the hope that it will be useful, | |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU Lesser General Public License for more details. | |
1da177e4 LT |
21 | */ |
22 | ||
23 | #ifndef _DVB_RINGBUFFER_H_ | |
24 | #define _DVB_RINGBUFFER_H_ | |
25 | ||
26 | #include <linux/spinlock.h> | |
27 | #include <linux/wait.h> | |
28 | ||
ff54c19d MCC |
29 | /** |
30 | * struct dvb_ringbuffer - Describes a ring buffer used at DVB framework | |
31 | * | |
32 | * @data: Area were the ringbuffer data is written | |
33 | * @size: size of the ringbuffer | |
34 | * @pread: next position to read | |
35 | * @pwrite: next position to write | |
36 | * @error: used by ringbuffer clients to indicate that an error happened. | |
37 | * @queue: Wait queue used by ringbuffer clients to indicate when buffer | |
38 | * was filled | |
39 | * @lock: Spinlock used to protect the ringbuffer | |
40 | */ | |
1da177e4 | 41 | struct dvb_ringbuffer { |
afd1a0c9 MCC |
42 | u8 *data; |
43 | ssize_t size; | |
44 | ssize_t pread; | |
45 | ssize_t pwrite; | |
9d9d6bae | 46 | int error; |
1da177e4 | 47 | |
afd1a0c9 MCC |
48 | wait_queue_head_t queue; |
49 | spinlock_t lock; | |
1da177e4 LT |
50 | }; |
51 | ||
52 | #define DVB_RINGBUFFER_PKTHDRSIZE 3 | |
53 | ||
ff54c19d MCC |
54 | /** |
55 | * dvb_ringbuffer_init - initialize ring buffer, lock and queue | |
56 | * | |
57 | * @rbuf: pointer to struct dvb_ringbuffer | |
58 | * @data: pointer to the buffer where the data will be stored | |
59 | * @len: bytes from ring buffer into @buf | |
60 | */ | |
61 | extern void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, | |
62 | size_t len); | |
1da177e4 | 63 | |
ff54c19d MCC |
64 | /** |
65 | * dvb_ringbuffer_empty - test whether buffer is empty | |
66 | * | |
67 | * @rbuf: pointer to struct dvb_ringbuffer | |
68 | */ | |
1da177e4 LT |
69 | extern int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf); |
70 | ||
ff54c19d MCC |
71 | /** |
72 | * dvb_ringbuffer_free - returns the number of free bytes in the buffer | |
73 | * | |
74 | * @rbuf: pointer to struct dvb_ringbuffer | |
75 | * | |
76 | * Return: number of free bytes in the buffer | |
77 | */ | |
1da177e4 LT |
78 | extern ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf); |
79 | ||
ff54c19d MCC |
80 | /** |
81 | * dvb_ringbuffer_avail - returns the number of bytes waiting in the buffer | |
82 | * | |
83 | * @rbuf: pointer to struct dvb_ringbuffer | |
84 | * | |
85 | * Return: number of bytes waiting in the buffer | |
86 | */ | |
1da177e4 LT |
87 | extern ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf); |
88 | ||
ff54c19d MCC |
89 | /** |
90 | * dvb_ringbuffer_reset - resets the ringbuffer to initial state | |
91 | * | |
92 | * @rbuf: pointer to struct dvb_ringbuffer | |
93 | * | |
94 | * Resets the read and write pointers to zero and flush the buffer. | |
95 | * | |
2a86e373 MCC |
96 | * This counts as a read and write operation |
97 | */ | |
48c01a9c AO |
98 | extern void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf); |
99 | ||
ff54c19d MCC |
100 | /* |
101 | * read routines & macros | |
102 | */ | |
103 | ||
104 | /** | |
105 | * dvb_ringbuffer_flush - flush buffer | |
106 | * | |
107 | * @rbuf: pointer to struct dvb_ringbuffer | |
108 | */ | |
1da177e4 LT |
109 | extern void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf); |
110 | ||
ff54c19d MCC |
111 | /** |
112 | * dvb_ringbuffer_flush_spinlock_wakeup- flush buffer protected by spinlock | |
113 | * and wake-up waiting task(s) | |
114 | * | |
115 | * @rbuf: pointer to struct dvb_ringbuffer | |
116 | */ | |
1da177e4 LT |
117 | extern void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf); |
118 | ||
9aa9d928 MCC |
119 | /** |
120 | * DVB_RINGBUFFER_PEEK - peek at byte @offs in the buffer | |
121 | * | |
122 | * @rbuf: pointer to struct dvb_ringbuffer | |
123 | * @offs: offset inside the ringbuffer | |
124 | */ | |
ff54c19d | 125 | #define DVB_RINGBUFFER_PEEK(rbuf, offs) \ |
9aa9d928 | 126 | ((rbuf)->data[((rbuf)->pread + (offs)) % (rbuf)->size]) |
1da177e4 | 127 | |
9aa9d928 MCC |
128 | /** |
129 | * DVB_RINGBUFFER_SKIP - advance read ptr by @num bytes | |
130 | * | |
131 | * @rbuf: pointer to struct dvb_ringbuffer | |
132 | * @num: number of bytes to advance | |
133 | */ | |
ff54c19d MCC |
134 | #define DVB_RINGBUFFER_SKIP(rbuf, num) {\ |
135 | (rbuf)->pread = ((rbuf)->pread + (num)) % (rbuf)->size;\ | |
136 | } | |
1da177e4 | 137 | |
ff54c19d | 138 | /** |
9332ef9d | 139 | * dvb_ringbuffer_read_user - Reads a buffer into a user pointer |
ff54c19d MCC |
140 | * |
141 | * @rbuf: pointer to struct dvb_ringbuffer | |
142 | * @buf: pointer to the buffer where the data will be stored | |
143 | * @len: bytes from ring buffer into @buf | |
144 | * | |
145 | * This variant assumes that the buffer is a memory at the userspace. So, | |
146 | * it will internally call copy_to_user(). | |
147 | * | |
148 | * Return: number of bytes transferred or -EFAULT | |
2a86e373 | 149 | */ |
b0ba0e3a AV |
150 | extern ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, |
151 | u8 __user *buf, size_t len); | |
ff54c19d MCC |
152 | |
153 | /** | |
154 | * dvb_ringbuffer_read - Reads a buffer into a pointer | |
155 | * | |
156 | * @rbuf: pointer to struct dvb_ringbuffer | |
157 | * @buf: pointer to the buffer where the data will be stored | |
158 | * @len: bytes from ring buffer into @buf | |
159 | * | |
160 | * This variant assumes that the buffer is a memory at the Kernel space | |
161 | * | |
162 | * Return: number of bytes transferred or -EFAULT | |
163 | */ | |
b0ba0e3a AV |
164 | extern void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, |
165 | u8 *buf, size_t len); | |
1da177e4 | 166 | |
1da177e4 | 167 | /* |
ff54c19d MCC |
168 | * write routines & macros |
169 | */ | |
170 | ||
9aa9d928 MCC |
171 | /** |
172 | * DVB_RINGBUFFER_WRITE_BYTE - write single byte to ring buffer | |
173 | * | |
174 | * @rbuf: pointer to struct dvb_ringbuffer | |
175 | * @byte: byte to write | |
176 | */ | |
ff54c19d MCC |
177 | #define DVB_RINGBUFFER_WRITE_BYTE(rbuf, byte) \ |
178 | { (rbuf)->data[(rbuf)->pwrite] = (byte); \ | |
179 | (rbuf)->pwrite = ((rbuf)->pwrite + 1) % (rbuf)->size; } | |
180 | ||
181 | /** | |
182 | * dvb_ringbuffer_write - Writes a buffer into the ringbuffer | |
183 | * | |
184 | * @rbuf: pointer to struct dvb_ringbuffer | |
185 | * @buf: pointer to the buffer where the data will be read | |
186 | * @len: bytes from ring buffer into @buf | |
187 | * | |
188 | * This variant assumes that the buffer is a memory at the Kernel space | |
189 | * | |
190 | * return: number of bytes transferred or -EFAULT | |
191 | */ | |
1da177e4 | 192 | extern ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, |
50c25fff | 193 | size_t len); |
ff54c19d MCC |
194 | |
195 | /** | |
9332ef9d | 196 | * dvb_ringbuffer_write_user - Writes a buffer received via a user pointer |
ff54c19d MCC |
197 | * |
198 | * @rbuf: pointer to struct dvb_ringbuffer | |
199 | * @buf: pointer to the buffer where the data will be read | |
200 | * @len: bytes from ring buffer into @buf | |
201 | * | |
202 | * This variant assumes that the buffer is a memory at the userspace. So, | |
203 | * it will internally call copy_from_user(). | |
204 | * | |
205 | * Return: number of bytes transferred or -EFAULT | |
206 | */ | |
04da2dae | 207 | extern ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf, |
ff54c19d | 208 | const u8 __user *buf, size_t len); |
1da177e4 | 209 | |
1da177e4 | 210 | /** |
2a86e373 | 211 | * dvb_ringbuffer_pkt_write - Write a packet into the ringbuffer. |
1da177e4 | 212 | * |
2a86e373 MCC |
213 | * @rbuf: Ringbuffer to write to. |
214 | * @buf: Buffer to write. | |
215 | * @len: Length of buffer (currently limited to 65535 bytes max). | |
ff54c19d MCC |
216 | * |
217 | * Return: Number of bytes written, or -EFAULT, -ENOMEM, -EVINAL. | |
1da177e4 | 218 | */ |
ff54c19d | 219 | extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8 *buf, |
50c25fff | 220 | size_t len); |
1da177e4 LT |
221 | |
222 | /** | |
2a86e373 | 223 | * dvb_ringbuffer_pkt_read_user - Read from a packet in the ringbuffer. |
2a86e373 MCC |
224 | * |
225 | * @rbuf: Ringbuffer concerned. | |
226 | * @idx: Packet index as returned by dvb_ringbuffer_pkt_next(). | |
227 | * @offset: Offset into packet to read from. | |
228 | * @buf: Destination buffer for data. | |
229 | * @len: Size of destination buffer. | |
230 | * | |
ff54c19d | 231 | * Return: Number of bytes read, or -EFAULT. |
7a23c257 MCC |
232 | * |
233 | * .. note:: | |
234 | * | |
235 | * unlike dvb_ringbuffer_read(), this does **NOT** update the read pointer | |
236 | * in the ringbuffer. You must use dvb_ringbuffer_pkt_dispose() to mark a | |
237 | * packet as no longer required. | |
1da177e4 | 238 | */ |
7a23c257 MCC |
239 | extern ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, |
240 | size_t idx, | |
ff54c19d | 241 | int offset, u8 __user *buf, |
7a23c257 | 242 | size_t len); |
2a86e373 MCC |
243 | |
244 | /** | |
245 | * dvb_ringbuffer_pkt_read - Read from a packet in the ringbuffer. | |
246 | * Note: unlike dvb_ringbuffer_read_user(), this DOES update the read pointer | |
247 | * in the ringbuffer. | |
248 | * | |
249 | * @rbuf: Ringbuffer concerned. | |
250 | * @idx: Packet index as returned by dvb_ringbuffer_pkt_next(). | |
251 | * @offset: Offset into packet to read from. | |
252 | * @buf: Destination buffer for data. | |
253 | * @len: Size of destination buffer. | |
254 | * | |
ff54c19d | 255 | * Return: Number of bytes read, or -EFAULT. |
2a86e373 | 256 | */ |
1da177e4 | 257 | extern ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx, |
b0ba0e3a | 258 | int offset, u8 *buf, size_t len); |
1da177e4 LT |
259 | |
260 | /** | |
2a86e373 | 261 | * dvb_ringbuffer_pkt_dispose - Dispose of a packet in the ring buffer. |
1da177e4 | 262 | * |
2a86e373 MCC |
263 | * @rbuf: Ring buffer concerned. |
264 | * @idx: Packet index as returned by dvb_ringbuffer_pkt_next(). | |
1da177e4 LT |
265 | */ |
266 | extern void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx); | |
267 | ||
268 | /** | |
2a86e373 | 269 | * dvb_ringbuffer_pkt_next - Get the index of the next packet in a ringbuffer. |
1da177e4 | 270 | * |
2a86e373 MCC |
271 | * @rbuf: Ringbuffer concerned. |
272 | * @idx: Previous packet index, or -1 to return the first packet index. | |
ff54c19d MCC |
273 | * @pktlen: On success, will be updated to contain the length of the packet |
274 | * in bytes. | |
1da177e4 LT |
275 | * returns Packet index (if >=0), or -1 if no packets available. |
276 | */ | |
ff54c19d MCC |
277 | extern ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, |
278 | size_t idx, size_t *pktlen); | |
1da177e4 | 279 | |
1da177e4 | 280 | #endif /* _DVB_RINGBUFFER_H_ */ |