dm thin metadata: fix __udivdi3 undefined on 32-bit
[linux/fpc-iii.git] / drivers / media / dvb-core / dvb_ringbuffer.h
blob3ebc2d34b4a2f3b84ed5721dfce75ee15a964bb9
1 /*
3 * dvb_ringbuffer.h: ring buffer implementation for the dvb driver
5 * Copyright (C) 2003 Oliver Endriss
6 * Copyright (C) 2004 Andrew de Quincey
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
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.
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.
22 * You should have received a copy of the GNU Lesser General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 #ifndef _DVB_RINGBUFFER_H_
28 #define _DVB_RINGBUFFER_H_
30 #include <linux/spinlock.h>
31 #include <linux/wait.h>
33 struct dvb_ringbuffer {
34 u8 *data;
35 ssize_t size;
36 ssize_t pread;
37 ssize_t pwrite;
38 int error;
40 wait_queue_head_t queue;
41 spinlock_t lock;
44 #define DVB_RINGBUFFER_PKTHDRSIZE 3
48 * Notes:
49 * ------
50 * (1) For performance reasons read and write routines don't check buffer sizes
51 * and/or number of bytes free/available. This has to be done before these
52 * routines are called. For example:
54 * *** write @buflen: bytes ***
55 * free = dvb_ringbuffer_free(rbuf);
56 * if (free >= buflen)
57 * count = dvb_ringbuffer_write(rbuf, buffer, buflen);
58 * else
59 * ...
61 * *** read min. 1000, max. @bufsize: bytes ***
62 * avail = dvb_ringbuffer_avail(rbuf);
63 * if (avail >= 1000)
64 * count = dvb_ringbuffer_read(rbuf, buffer, min(avail, bufsize));
65 * else
66 * ...
68 * (2) If there is exactly one reader and one writer, there is no need
69 * to lock read or write operations.
70 * Two or more readers must be locked against each other.
71 * Flushing the buffer counts as a read operation.
72 * Resetting the buffer counts as a read and write operation.
73 * Two or more writers must be locked against each other.
76 /* initialize ring buffer, lock and queue */
77 extern void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len);
79 /* test whether buffer is empty */
80 extern int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf);
82 /* return the number of free bytes in the buffer */
83 extern ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf);
85 /* return the number of bytes waiting in the buffer */
86 extern ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf);
90 * Reset the read and write pointers to zero and flush the buffer
91 * This counts as a read and write operation
93 extern void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf);
96 /* read routines & macros */
97 /* ---------------------- */
98 /* flush buffer */
99 extern void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf);
101 /* flush buffer protected by spinlock and wake-up waiting task(s) */
102 extern void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf);
104 /* peek at byte @offs: in the buffer */
105 #define DVB_RINGBUFFER_PEEK(rbuf,offs) \
106 (rbuf)->data[((rbuf)->pread+(offs))%(rbuf)->size]
108 /* advance read ptr by @num: bytes */
109 #define DVB_RINGBUFFER_SKIP(rbuf,num) \
110 (rbuf)->pread=((rbuf)->pread+(num))%(rbuf)->size
113 * read @len: bytes from ring buffer into @buf:
114 * @usermem: specifies whether @buf: resides in user space
115 * returns number of bytes transferred or -EFAULT
117 extern ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf,
118 u8 __user *buf, size_t len);
119 extern void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf,
120 u8 *buf, size_t len);
123 /* write routines & macros */
124 /* ----------------------- */
125 /* write single byte to ring buffer */
126 #define DVB_RINGBUFFER_WRITE_BYTE(rbuf,byte) \
127 { (rbuf)->data[(rbuf)->pwrite]=(byte); \
128 (rbuf)->pwrite=((rbuf)->pwrite+1)%(rbuf)->size; }
130 * write @len: bytes to ring buffer
131 * @usermem: specifies whether @buf: resides in user space
132 * returns number of bytes transferred or -EFAULT
134 extern ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf,
135 size_t len);
136 extern ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
137 const u8 __user *buf, size_t len);
141 * dvb_ringbuffer_pkt_write - Write a packet into the ringbuffer.
143 * @rbuf: Ringbuffer to write to.
144 * @buf: Buffer to write.
145 * @len: Length of buffer (currently limited to 65535 bytes max).
146 * returns Number of bytes written, or -EFAULT, -ENOMEM, -EVINAL.
148 extern ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf,
149 size_t len);
152 * dvb_ringbuffer_pkt_read_user - Read from a packet in the ringbuffer.
153 * Note: unlike dvb_ringbuffer_read(), this does NOT update the read pointer
154 * in the ringbuffer. You must use dvb_ringbuffer_pkt_dispose() to mark a
155 * packet as no longer required.
157 * @rbuf: Ringbuffer concerned.
158 * @idx: Packet index as returned by dvb_ringbuffer_pkt_next().
159 * @offset: Offset into packet to read from.
160 * @buf: Destination buffer for data.
161 * @len: Size of destination buffer.
163 * returns Number of bytes read, or -EFAULT.
165 extern ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, size_t idx,
166 int offset, u8 __user *buf, size_t len);
169 * dvb_ringbuffer_pkt_read - Read from a packet in the ringbuffer.
170 * Note: unlike dvb_ringbuffer_read_user(), this DOES update the read pointer
171 * in the ringbuffer.
173 * @rbuf: Ringbuffer concerned.
174 * @idx: Packet index as returned by dvb_ringbuffer_pkt_next().
175 * @offset: Offset into packet to read from.
176 * @buf: Destination buffer for data.
177 * @len: Size of destination buffer.
179 * returns Number of bytes read, or -EFAULT.
181 extern ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
182 int offset, u8 *buf, size_t len);
185 * dvb_ringbuffer_pkt_dispose - Dispose of a packet in the ring buffer.
187 * @rbuf: Ring buffer concerned.
188 * @idx: Packet index as returned by dvb_ringbuffer_pkt_next().
190 extern void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx);
193 * dvb_ringbuffer_pkt_next - Get the index of the next packet in a ringbuffer.
195 * @rbuf: Ringbuffer concerned.
196 * @idx: Previous packet index, or -1 to return the first packet index.
197 * @pktlen: On success, will be updated to contain the length of the packet in bytes.
198 * returns Packet index (if >=0), or -1 if no packets available.
200 extern ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen);
203 #endif /* _DVB_RINGBUFFER_H_ */