3 * dvb_ringbuffer.c: 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
10 * & Marcus Metzler 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.
29 #define __KERNEL_SYSCALLS__
30 #include <linux/errno.h>
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/sched.h>
34 #include <linux/string.h>
35 #include <asm/uaccess.h>
37 #include "dvb_ringbuffer.h"
40 #define PKT_DISPOSED 1
43 void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len)
45 rbuf->pread=rbuf->pwrite=0;
49 init_waitqueue_head(&rbuf->queue);
51 spin_lock_init(&(rbuf->lock));
56 int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf)
58 return (rbuf->pread==rbuf->pwrite);
63 ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf)
67 free = rbuf->pread - rbuf->pwrite;
75 ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf)
79 avail = rbuf->pwrite - rbuf->pread;
87 void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf)
89 rbuf->pread = rbuf->pwrite;
94 void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)
98 spin_lock_irqsave(&rbuf->lock, flags);
99 dvb_ringbuffer_flush(rbuf);
100 spin_unlock_irqrestore(&rbuf->lock, flags);
102 wake_up(&rbuf->queue);
107 ssize_t dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len, int usermem)
112 split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
115 memcpy(buf, rbuf->data+rbuf->pread, split);
117 if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
124 memcpy(buf, rbuf->data+rbuf->pread, todo);
126 if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
129 rbuf->pread = (rbuf->pread + todo) % rbuf->size;
136 ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf,
137 size_t len, int usermem)
142 split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
146 memcpy(rbuf->data+rbuf->pwrite, buf, split);
148 if (copy_from_user(rbuf->data+rbuf->pwrite,
156 memcpy(rbuf->data+rbuf->pwrite, buf, todo);
158 if (copy_from_user(rbuf->data+rbuf->pwrite, buf, todo))
161 rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size;
166 ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len, int usermem)
169 ssize_t oldpwrite = rbuf->pwrite;
171 DVB_RINGBUFFER_WRITE_BYTE(rbuf, len >> 8);
172 DVB_RINGBUFFER_WRITE_BYTE(rbuf, len & 0xff);
173 DVB_RINGBUFFER_WRITE_BYTE(rbuf, PKT_READY);
174 status = dvb_ringbuffer_write(rbuf, buf, len, usermem);
176 if (status < 0) rbuf->pwrite = oldpwrite;
180 ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
181 int offset, u8* buf, size_t len, int usermem)
187 pktlen = rbuf->data[idx] << 8;
188 pktlen |= rbuf->data[(idx + 1) % rbuf->size];
189 if (offset > pktlen) return -EINVAL;
190 if ((offset + len) > pktlen) len = pktlen - offset;
192 idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
194 split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
197 memcpy(buf, rbuf->data+idx, split);
199 if (copy_to_user(buf, rbuf->data+idx, split))
206 memcpy(buf, rbuf->data+idx, todo);
208 if (copy_to_user(buf, rbuf->data+idx, todo))
214 void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx)
218 rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED;
220 // clean up disposed packets
221 while(dvb_ringbuffer_avail(rbuf) > DVB_RINGBUFFER_PKTHDRSIZE) {
222 if (DVB_RINGBUFFER_PEEK(rbuf, 2) == PKT_DISPOSED) {
223 pktlen = DVB_RINGBUFFER_PEEK(rbuf, 0) << 8;
224 pktlen |= DVB_RINGBUFFER_PEEK(rbuf, 1);
225 DVB_RINGBUFFER_SKIP(rbuf, pktlen + DVB_RINGBUFFER_PKTHDRSIZE);
227 // first packet is not disposed, so we stop cleaning now
233 ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen)
242 curpktlen = rbuf->data[idx] << 8;
243 curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
244 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
247 consumed = (idx - rbuf->pread) % rbuf->size;
249 while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) {
251 curpktlen = rbuf->data[idx] << 8;
252 curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
253 curpktstatus = rbuf->data[(idx + 2) % rbuf->size];
255 if (curpktstatus == PKT_READY) {
260 consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE;
261 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
264 // no packets available
270 EXPORT_SYMBOL(dvb_ringbuffer_init);
271 EXPORT_SYMBOL(dvb_ringbuffer_empty);
272 EXPORT_SYMBOL(dvb_ringbuffer_free);
273 EXPORT_SYMBOL(dvb_ringbuffer_avail);
274 EXPORT_SYMBOL(dvb_ringbuffer_flush);
275 EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup);
276 EXPORT_SYMBOL(dvb_ringbuffer_read);
277 EXPORT_SYMBOL(dvb_ringbuffer_write);
278 EXPORT_SYMBOL(dvb_ringbuffer_pkt_write);
279 EXPORT_SYMBOL(dvb_ringbuffer_pkt_read);
280 EXPORT_SYMBOL(dvb_ringbuffer_pkt_dispose);
281 EXPORT_SYMBOL(dvb_ringbuffer_pkt_next);