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 #include <linux/errno.h>
30 #include <linux/kernel.h>
31 #include <linux/module.h>
32 #include <linux/sched.h>
33 #include <linux/string.h>
34 #include <asm/uaccess.h>
36 #include "dvb_ringbuffer.h"
39 #define PKT_DISPOSED 1
42 void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len)
44 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;
92 EXPORT_SYMBOL(dvb_ringbuffer_flush);
94 void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf)
96 rbuf->pread = rbuf->pwrite = 0;
100 void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)
104 spin_lock_irqsave(&rbuf->lock, flags);
105 dvb_ringbuffer_flush(rbuf);
106 spin_unlock_irqrestore(&rbuf->lock, flags);
108 wake_up(&rbuf->queue);
111 ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, u8 __user *buf, size_t len)
116 split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
118 if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
124 if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
127 rbuf->pread = (rbuf->pread + todo) % rbuf->size;
132 void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len)
137 split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
139 memcpy(buf, rbuf->data+rbuf->pread, split);
144 memcpy(buf, rbuf->data+rbuf->pread, todo);
146 rbuf->pread = (rbuf->pread + todo) % rbuf->size;
150 ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len)
155 split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
158 memcpy(rbuf->data+rbuf->pwrite, buf, split);
163 memcpy(rbuf->data+rbuf->pwrite, buf, todo);
164 rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size;
169 ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len)
172 ssize_t oldpwrite = rbuf->pwrite;
174 DVB_RINGBUFFER_WRITE_BYTE(rbuf, len >> 8);
175 DVB_RINGBUFFER_WRITE_BYTE(rbuf, len & 0xff);
176 DVB_RINGBUFFER_WRITE_BYTE(rbuf, PKT_READY);
177 status = dvb_ringbuffer_write(rbuf, buf, len);
179 if (status < 0) rbuf->pwrite = oldpwrite;
183 ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, size_t idx,
184 int offset, u8 __user *buf, size_t len)
190 pktlen = rbuf->data[idx] << 8;
191 pktlen |= rbuf->data[(idx + 1) % rbuf->size];
192 if (offset > pktlen) return -EINVAL;
193 if ((offset + len) > pktlen) len = pktlen - offset;
195 idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
197 split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
199 if (copy_to_user(buf, rbuf->data+idx, split))
205 if (copy_to_user(buf, rbuf->data+idx, todo))
211 ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
212 int offset, u8* buf, size_t len)
218 pktlen = rbuf->data[idx] << 8;
219 pktlen |= rbuf->data[(idx + 1) % rbuf->size];
220 if (offset > pktlen) return -EINVAL;
221 if ((offset + len) > pktlen) len = pktlen - offset;
223 idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
225 split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
227 memcpy(buf, rbuf->data+idx, split);
232 memcpy(buf, rbuf->data+idx, todo);
236 void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx)
240 rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED;
242 // clean up disposed packets
243 while(dvb_ringbuffer_avail(rbuf) > DVB_RINGBUFFER_PKTHDRSIZE) {
244 if (DVB_RINGBUFFER_PEEK(rbuf, 2) == PKT_DISPOSED) {
245 pktlen = DVB_RINGBUFFER_PEEK(rbuf, 0) << 8;
246 pktlen |= DVB_RINGBUFFER_PEEK(rbuf, 1);
247 DVB_RINGBUFFER_SKIP(rbuf, pktlen + DVB_RINGBUFFER_PKTHDRSIZE);
249 // first packet is not disposed, so we stop cleaning now
255 ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen)
264 curpktlen = rbuf->data[idx] << 8;
265 curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
266 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
269 consumed = (idx - rbuf->pread) % rbuf->size;
271 while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) {
273 curpktlen = rbuf->data[idx] << 8;
274 curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
275 curpktstatus = rbuf->data[(idx + 2) % rbuf->size];
277 if (curpktstatus == PKT_READY) {
282 consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE;
283 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
286 // no packets available
292 EXPORT_SYMBOL(dvb_ringbuffer_init);
293 EXPORT_SYMBOL(dvb_ringbuffer_empty);
294 EXPORT_SYMBOL(dvb_ringbuffer_free);
295 EXPORT_SYMBOL(dvb_ringbuffer_avail);
296 EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup);
297 EXPORT_SYMBOL(dvb_ringbuffer_read_user);
298 EXPORT_SYMBOL(dvb_ringbuffer_read);
299 EXPORT_SYMBOL(dvb_ringbuffer_write);