Merge branches 'release', 'acpica', 'bugzilla-10224', 'bugzilla-9772', 'bugzilla...
[linux-2.6] / drivers / media / dvb / dvb-core / dvb_ringbuffer.c
1 /*
2  *
3  * dvb_ringbuffer.c: 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
10  *                       & Marcus Metzler 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.
21  *
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.
25  */
26
27
28
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>
35
36 #include "dvb_ringbuffer.h"
37
38 #define PKT_READY 0
39 #define PKT_DISPOSED 1
40
41
42 void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len)
43 {
44         rbuf->pread=rbuf->pwrite=0;
45         rbuf->data=data;
46         rbuf->size=len;
47         rbuf->error=0;
48
49         init_waitqueue_head(&rbuf->queue);
50
51         spin_lock_init(&(rbuf->lock));
52 }
53
54
55
56 int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf)
57 {
58         return (rbuf->pread==rbuf->pwrite);
59 }
60
61
62
63 ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf)
64 {
65         ssize_t free;
66
67         free = rbuf->pread - rbuf->pwrite;
68         if (free <= 0)
69                 free += rbuf->size;
70         return free-1;
71 }
72
73
74
75 ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf)
76 {
77         ssize_t avail;
78
79         avail = rbuf->pwrite - rbuf->pread;
80         if (avail < 0)
81                 avail += rbuf->size;
82         return avail;
83 }
84
85
86
87 void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf)
88 {
89         rbuf->pread = rbuf->pwrite;
90         rbuf->error = 0;
91 }
92
93 void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf)
94 {
95         rbuf->pread = rbuf->pwrite = 0;
96         rbuf->error = 0;
97 }
98
99 void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)
100 {
101         unsigned long flags;
102
103         spin_lock_irqsave(&rbuf->lock, flags);
104         dvb_ringbuffer_flush(rbuf);
105         spin_unlock_irqrestore(&rbuf->lock, flags);
106
107         wake_up(&rbuf->queue);
108 }
109
110
111
112 ssize_t dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len, int usermem)
113 {
114         size_t todo = len;
115         size_t split;
116
117         split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
118         if (split > 0) {
119                 if (!usermem)
120                         memcpy(buf, rbuf->data+rbuf->pread, split);
121                 else
122                         if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
123                                 return -EFAULT;
124                 buf += split;
125                 todo -= split;
126                 rbuf->pread = 0;
127         }
128         if (!usermem)
129                 memcpy(buf, rbuf->data+rbuf->pread, todo);
130         else
131                 if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
132                         return -EFAULT;
133
134         rbuf->pread = (rbuf->pread + todo) % rbuf->size;
135
136         return len;
137 }
138
139
140
141 ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len)
142 {
143         size_t todo = len;
144         size_t split;
145
146         split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
147
148         if (split > 0) {
149                 memcpy(rbuf->data+rbuf->pwrite, buf, split);
150                 buf += split;
151                 todo -= split;
152                 rbuf->pwrite = 0;
153         }
154         memcpy(rbuf->data+rbuf->pwrite, buf, todo);
155         rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size;
156
157         return len;
158 }
159
160 ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len)
161 {
162         int status;
163         ssize_t oldpwrite = rbuf->pwrite;
164
165         DVB_RINGBUFFER_WRITE_BYTE(rbuf, len >> 8);
166         DVB_RINGBUFFER_WRITE_BYTE(rbuf, len & 0xff);
167         DVB_RINGBUFFER_WRITE_BYTE(rbuf, PKT_READY);
168         status = dvb_ringbuffer_write(rbuf, buf, len);
169
170         if (status < 0) rbuf->pwrite = oldpwrite;
171         return status;
172 }
173
174 ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
175                                 int offset, u8* buf, size_t len, int usermem)
176 {
177         size_t todo;
178         size_t split;
179         size_t pktlen;
180
181         pktlen = rbuf->data[idx] << 8;
182         pktlen |= rbuf->data[(idx + 1) % rbuf->size];
183         if (offset > pktlen) return -EINVAL;
184         if ((offset + len) > pktlen) len = pktlen - offset;
185
186         idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
187         todo = len;
188         split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
189         if (split > 0) {
190                 if (!usermem)
191                         memcpy(buf, rbuf->data+idx, split);
192                 else
193                         if (copy_to_user(buf, rbuf->data+idx, split))
194                                 return -EFAULT;
195                 buf += split;
196                 todo -= split;
197                 idx = 0;
198         }
199         if (!usermem)
200                 memcpy(buf, rbuf->data+idx, todo);
201         else
202                 if (copy_to_user(buf, rbuf->data+idx, todo))
203                         return -EFAULT;
204
205         return len;
206 }
207
208 void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx)
209 {
210         size_t pktlen;
211
212         rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED;
213
214         // clean up disposed packets
215         while(dvb_ringbuffer_avail(rbuf) > DVB_RINGBUFFER_PKTHDRSIZE) {
216                 if (DVB_RINGBUFFER_PEEK(rbuf, 2) == PKT_DISPOSED) {
217                         pktlen = DVB_RINGBUFFER_PEEK(rbuf, 0) << 8;
218                         pktlen |= DVB_RINGBUFFER_PEEK(rbuf, 1);
219                         DVB_RINGBUFFER_SKIP(rbuf, pktlen + DVB_RINGBUFFER_PKTHDRSIZE);
220                 } else {
221                         // first packet is not disposed, so we stop cleaning now
222                         break;
223                 }
224         }
225 }
226
227 ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen)
228 {
229         int consumed;
230         int curpktlen;
231         int curpktstatus;
232
233         if (idx == -1) {
234                idx = rbuf->pread;
235         } else {
236                 curpktlen = rbuf->data[idx] << 8;
237                 curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
238                 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
239         }
240
241         consumed = (idx - rbuf->pread) % rbuf->size;
242
243         while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) {
244
245                 curpktlen = rbuf->data[idx] << 8;
246                 curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
247                 curpktstatus = rbuf->data[(idx + 2) % rbuf->size];
248
249                 if (curpktstatus == PKT_READY) {
250                         *pktlen = curpktlen;
251                         return idx;
252                 }
253
254                 consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE;
255                 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
256         }
257
258         // no packets available
259         return -1;
260 }
261
262
263
264 EXPORT_SYMBOL(dvb_ringbuffer_init);
265 EXPORT_SYMBOL(dvb_ringbuffer_empty);
266 EXPORT_SYMBOL(dvb_ringbuffer_free);
267 EXPORT_SYMBOL(dvb_ringbuffer_avail);
268 EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup);
269 EXPORT_SYMBOL(dvb_ringbuffer_read);
270 EXPORT_SYMBOL(dvb_ringbuffer_write);