Merge branch 'linus' into x86/x2apic
[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 ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, u8 __user *buf, size_t len)
111 {
112         size_t todo = len;
113         size_t split;
114
115         split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
116         if (split > 0) {
117                 if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
118                         return -EFAULT;
119                 buf += split;
120                 todo -= split;
121                 rbuf->pread = 0;
122         }
123         if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
124                 return -EFAULT;
125
126         rbuf->pread = (rbuf->pread + todo) % rbuf->size;
127
128         return len;
129 }
130
131 void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len)
132 {
133         size_t todo = len;
134         size_t split;
135
136         split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
137         if (split > 0) {
138                 memcpy(buf, rbuf->data+rbuf->pread, split);
139                 buf += split;
140                 todo -= split;
141                 rbuf->pread = 0;
142         }
143         memcpy(buf, rbuf->data+rbuf->pread, todo);
144
145         rbuf->pread = (rbuf->pread + todo) % rbuf->size;
146 }
147
148
149 ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len)
150 {
151         size_t todo = len;
152         size_t split;
153
154         split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
155
156         if (split > 0) {
157                 memcpy(rbuf->data+rbuf->pwrite, buf, split);
158                 buf += split;
159                 todo -= split;
160                 rbuf->pwrite = 0;
161         }
162         memcpy(rbuf->data+rbuf->pwrite, buf, todo);
163         rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size;
164
165         return len;
166 }
167
168 ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len)
169 {
170         int status;
171         ssize_t oldpwrite = rbuf->pwrite;
172
173         DVB_RINGBUFFER_WRITE_BYTE(rbuf, len >> 8);
174         DVB_RINGBUFFER_WRITE_BYTE(rbuf, len & 0xff);
175         DVB_RINGBUFFER_WRITE_BYTE(rbuf, PKT_READY);
176         status = dvb_ringbuffer_write(rbuf, buf, len);
177
178         if (status < 0) rbuf->pwrite = oldpwrite;
179         return status;
180 }
181
182 ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, size_t idx,
183                                 int offset, u8 __user *buf, size_t len)
184 {
185         size_t todo;
186         size_t split;
187         size_t pktlen;
188
189         pktlen = rbuf->data[idx] << 8;
190         pktlen |= rbuf->data[(idx + 1) % rbuf->size];
191         if (offset > pktlen) return -EINVAL;
192         if ((offset + len) > pktlen) len = pktlen - offset;
193
194         idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
195         todo = len;
196         split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
197         if (split > 0) {
198                 if (copy_to_user(buf, rbuf->data+idx, split))
199                         return -EFAULT;
200                 buf += split;
201                 todo -= split;
202                 idx = 0;
203         }
204         if (copy_to_user(buf, rbuf->data+idx, todo))
205                 return -EFAULT;
206
207         return len;
208 }
209
210 ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
211                                 int offset, u8* buf, size_t len)
212 {
213         size_t todo;
214         size_t split;
215         size_t pktlen;
216
217         pktlen = rbuf->data[idx] << 8;
218         pktlen |= rbuf->data[(idx + 1) % rbuf->size];
219         if (offset > pktlen) return -EINVAL;
220         if ((offset + len) > pktlen) len = pktlen - offset;
221
222         idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
223         todo = len;
224         split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
225         if (split > 0) {
226                 memcpy(buf, rbuf->data+idx, split);
227                 buf += split;
228                 todo -= split;
229                 idx = 0;
230         }
231         memcpy(buf, rbuf->data+idx, todo);
232         return len;
233 }
234
235 void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx)
236 {
237         size_t pktlen;
238
239         rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED;
240
241         // clean up disposed packets
242         while(dvb_ringbuffer_avail(rbuf) > DVB_RINGBUFFER_PKTHDRSIZE) {
243                 if (DVB_RINGBUFFER_PEEK(rbuf, 2) == PKT_DISPOSED) {
244                         pktlen = DVB_RINGBUFFER_PEEK(rbuf, 0) << 8;
245                         pktlen |= DVB_RINGBUFFER_PEEK(rbuf, 1);
246                         DVB_RINGBUFFER_SKIP(rbuf, pktlen + DVB_RINGBUFFER_PKTHDRSIZE);
247                 } else {
248                         // first packet is not disposed, so we stop cleaning now
249                         break;
250                 }
251         }
252 }
253
254 ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen)
255 {
256         int consumed;
257         int curpktlen;
258         int curpktstatus;
259
260         if (idx == -1) {
261                idx = rbuf->pread;
262         } else {
263                 curpktlen = rbuf->data[idx] << 8;
264                 curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
265                 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
266         }
267
268         consumed = (idx - rbuf->pread) % rbuf->size;
269
270         while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) {
271
272                 curpktlen = rbuf->data[idx] << 8;
273                 curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
274                 curpktstatus = rbuf->data[(idx + 2) % rbuf->size];
275
276                 if (curpktstatus == PKT_READY) {
277                         *pktlen = curpktlen;
278                         return idx;
279                 }
280
281                 consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE;
282                 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
283         }
284
285         // no packets available
286         return -1;
287 }
288
289
290
291 EXPORT_SYMBOL(dvb_ringbuffer_init);
292 EXPORT_SYMBOL(dvb_ringbuffer_empty);
293 EXPORT_SYMBOL(dvb_ringbuffer_free);
294 EXPORT_SYMBOL(dvb_ringbuffer_avail);
295 EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup);
296 EXPORT_SYMBOL(dvb_ringbuffer_read_user);
297 EXPORT_SYMBOL(dvb_ringbuffer_read);
298 EXPORT_SYMBOL(dvb_ringbuffer_write);