diff options
author | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
---|---|---|
committer | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
commit | fcc9d2e5a6c89d22b8b773a64fb4ad21ac318446 (patch) | |
tree | a57612d1888735a2ec7972891b68c1ac5ec8faea /drivers/media/dvb/dvb-core/dvb_ringbuffer.c | |
parent | 8dea78da5cee153b8af9c07a2745f6c55057fe12 (diff) |
Diffstat (limited to 'drivers/media/dvb/dvb-core/dvb_ringbuffer.c')
-rw-r--r-- | drivers/media/dvb/dvb-core/dvb_ringbuffer.c | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/drivers/media/dvb/dvb-core/dvb_ringbuffer.c b/drivers/media/dvb/dvb-core/dvb_ringbuffer.c new file mode 100644 index 00000000000..a5712cd7c65 --- /dev/null +++ b/drivers/media/dvb/dvb-core/dvb_ringbuffer.c | |||
@@ -0,0 +1,299 @@ | |||
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 | EXPORT_SYMBOL(dvb_ringbuffer_flush); | ||
93 | |||
94 | void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf) | ||
95 | { | ||
96 | rbuf->pread = rbuf->pwrite = 0; | ||
97 | rbuf->error = 0; | ||
98 | } | ||
99 | |||
100 | void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf) | ||
101 | { | ||
102 | unsigned long flags; | ||
103 | |||
104 | spin_lock_irqsave(&rbuf->lock, flags); | ||
105 | dvb_ringbuffer_flush(rbuf); | ||
106 | spin_unlock_irqrestore(&rbuf->lock, flags); | ||
107 | |||
108 | wake_up(&rbuf->queue); | ||
109 | } | ||
110 | |||
111 | ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, u8 __user *buf, size_t len) | ||
112 | { | ||
113 | size_t todo = len; | ||
114 | size_t split; | ||
115 | |||
116 | split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0; | ||
117 | if (split > 0) { | ||
118 | if (copy_to_user(buf, rbuf->data+rbuf->pread, split)) | ||
119 | return -EFAULT; | ||
120 | buf += split; | ||
121 | todo -= split; | ||
122 | rbuf->pread = 0; | ||
123 | } | ||
124 | if (copy_to_user(buf, rbuf->data+rbuf->pread, todo)) | ||
125 | return -EFAULT; | ||
126 | |||
127 | rbuf->pread = (rbuf->pread + todo) % rbuf->size; | ||
128 | |||
129 | return len; | ||
130 | } | ||
131 | |||
132 | void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len) | ||
133 | { | ||
134 | size_t todo = len; | ||
135 | size_t split; | ||
136 | |||
137 | split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0; | ||
138 | if (split > 0) { | ||
139 | memcpy(buf, rbuf->data+rbuf->pread, split); | ||
140 | buf += split; | ||
141 | todo -= split; | ||
142 | rbuf->pread = 0; | ||
143 | } | ||
144 | memcpy(buf, rbuf->data+rbuf->pread, todo); | ||
145 | |||
146 | rbuf->pread = (rbuf->pread + todo) % rbuf->size; | ||
147 | } | ||
148 | |||
149 | |||
150 | ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len) | ||
151 | { | ||
152 | size_t todo = len; | ||
153 | size_t split; | ||
154 | |||
155 | split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0; | ||
156 | |||
157 | if (split > 0) { | ||
158 | memcpy(rbuf->data+rbuf->pwrite, buf, split); | ||
159 | buf += split; | ||
160 | todo -= split; | ||
161 | rbuf->pwrite = 0; | ||
162 | } | ||
163 | memcpy(rbuf->data+rbuf->pwrite, buf, todo); | ||
164 | rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size; | ||
165 | |||
166 | return len; | ||
167 | } | ||
168 | |||
169 | ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len) | ||
170 | { | ||
171 | int status; | ||
172 | ssize_t oldpwrite = rbuf->pwrite; | ||
173 | |||
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); | ||
178 | |||
179 | if (status < 0) rbuf->pwrite = oldpwrite; | ||
180 | return status; | ||
181 | } | ||
182 | |||
183 | ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, size_t idx, | ||
184 | int offset, u8 __user *buf, size_t len) | ||
185 | { | ||
186 | size_t todo; | ||
187 | size_t split; | ||
188 | size_t pktlen; | ||
189 | |||
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; | ||
194 | |||
195 | idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size; | ||
196 | todo = len; | ||
197 | split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0; | ||
198 | if (split > 0) { | ||
199 | if (copy_to_user(buf, rbuf->data+idx, split)) | ||
200 | return -EFAULT; | ||
201 | buf += split; | ||
202 | todo -= split; | ||
203 | idx = 0; | ||
204 | } | ||
205 | if (copy_to_user(buf, rbuf->data+idx, todo)) | ||
206 | return -EFAULT; | ||
207 | |||
208 | return len; | ||
209 | } | ||
210 | |||
211 | ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx, | ||
212 | int offset, u8* buf, size_t len) | ||
213 | { | ||
214 | size_t todo; | ||
215 | size_t split; | ||
216 | size_t pktlen; | ||
217 | |||
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; | ||
222 | |||
223 | idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size; | ||
224 | todo = len; | ||
225 | split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0; | ||
226 | if (split > 0) { | ||
227 | memcpy(buf, rbuf->data+idx, split); | ||
228 | buf += split; | ||
229 | todo -= split; | ||
230 | idx = 0; | ||
231 | } | ||
232 | memcpy(buf, rbuf->data+idx, todo); | ||
233 | return len; | ||
234 | } | ||
235 | |||
236 | void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx) | ||
237 | { | ||
238 | size_t pktlen; | ||
239 | |||
240 | rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED; | ||
241 | |||
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); | ||
248 | } else { | ||
249 | // first packet is not disposed, so we stop cleaning now | ||
250 | break; | ||
251 | } | ||
252 | } | ||
253 | } | ||
254 | |||
255 | ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen) | ||
256 | { | ||
257 | int consumed; | ||
258 | int curpktlen; | ||
259 | int curpktstatus; | ||
260 | |||
261 | if (idx == -1) { | ||
262 | idx = rbuf->pread; | ||
263 | } else { | ||
264 | curpktlen = rbuf->data[idx] << 8; | ||
265 | curpktlen |= rbuf->data[(idx + 1) % rbuf->size]; | ||
266 | idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size; | ||
267 | } | ||
268 | |||
269 | consumed = (idx - rbuf->pread) % rbuf->size; | ||
270 | |||
271 | while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) { | ||
272 | |||
273 | curpktlen = rbuf->data[idx] << 8; | ||
274 | curpktlen |= rbuf->data[(idx + 1) % rbuf->size]; | ||
275 | curpktstatus = rbuf->data[(idx + 2) % rbuf->size]; | ||
276 | |||
277 | if (curpktstatus == PKT_READY) { | ||
278 | *pktlen = curpktlen; | ||
279 | return idx; | ||
280 | } | ||
281 | |||
282 | consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE; | ||
283 | idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size; | ||
284 | } | ||
285 | |||
286 | // no packets available | ||
287 | return -1; | ||
288 | } | ||
289 | |||
290 | |||
291 | |||
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); | ||