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Commit | Line | Data |
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1da177e4 LT |
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 | ||
1da177e4 LT |
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> | |
7c0f6ba6 | 34 | #include <linux/uaccess.h> |
1da177e4 LT |
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 | { | |
afd1a0c9 MCC |
44 | rbuf->pread=rbuf->pwrite=0; |
45 | rbuf->data=data; | |
46 | rbuf->size=len; | |
9d9d6bae | 47 | rbuf->error=0; |
1da177e4 | 48 | |
afd1a0c9 | 49 | init_waitqueue_head(&rbuf->queue); |
1da177e4 | 50 | |
afd1a0c9 | 51 | spin_lock_init(&(rbuf->lock)); |
1da177e4 LT |
52 | } |
53 | ||
54 | ||
55 | ||
56 | int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf) | |
57 | { | |
ca6e6126 SM |
58 | /* smp_load_acquire() to load write pointer on reader side |
59 | * this pairs with smp_store_release() in dvb_ringbuffer_write(), | |
60 | * dvb_ringbuffer_write_user(), or dvb_ringbuffer_reset() | |
61 | * | |
62 | * for memory barriers also see Documentation/circular-buffers.txt | |
63 | */ | |
64 | return (rbuf->pread == smp_load_acquire(&rbuf->pwrite)); | |
1da177e4 LT |
65 | } |
66 | ||
67 | ||
68 | ||
69 | ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf) | |
70 | { | |
afd1a0c9 | 71 | ssize_t free; |
1da177e4 | 72 | |
ca6e6126 SM |
73 | /* ACCESS_ONCE() to load read pointer on writer side |
74 | * this pairs with smp_store_release() in dvb_ringbuffer_read(), | |
75 | * dvb_ringbuffer_read_user(), dvb_ringbuffer_flush(), | |
76 | * or dvb_ringbuffer_reset() | |
77 | */ | |
78 | free = ACCESS_ONCE(rbuf->pread) - rbuf->pwrite; | |
afd1a0c9 MCC |
79 | if (free <= 0) |
80 | free += rbuf->size; | |
81 | return free-1; | |
1da177e4 LT |
82 | } |
83 | ||
84 | ||
85 | ||
86 | ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf) | |
87 | { | |
afd1a0c9 | 88 | ssize_t avail; |
1da177e4 | 89 | |
ca6e6126 SM |
90 | /* smp_load_acquire() to load write pointer on reader side |
91 | * this pairs with smp_store_release() in dvb_ringbuffer_write(), | |
92 | * dvb_ringbuffer_write_user(), or dvb_ringbuffer_reset() | |
93 | */ | |
94 | avail = smp_load_acquire(&rbuf->pwrite) - rbuf->pread; | |
afd1a0c9 MCC |
95 | if (avail < 0) |
96 | avail += rbuf->size; | |
97 | return avail; | |
1da177e4 LT |
98 | } |
99 | ||
100 | ||
101 | ||
102 | void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf) | |
103 | { | |
ca6e6126 SM |
104 | /* dvb_ringbuffer_flush() counts as read operation |
105 | * smp_load_acquire() to load write pointer | |
106 | * smp_store_release() to update read pointer, this ensures that the | |
107 | * correct pointer is visible for subsequent dvb_ringbuffer_free() | |
108 | * calls on other cpu cores | |
109 | */ | |
110 | smp_store_release(&rbuf->pread, smp_load_acquire(&rbuf->pwrite)); | |
9d9d6bae | 111 | rbuf->error = 0; |
1da177e4 | 112 | } |
126cd4bc | 113 | EXPORT_SYMBOL(dvb_ringbuffer_flush); |
1da177e4 | 114 | |
48c01a9c AO |
115 | void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf) |
116 | { | |
ca6e6126 SM |
117 | /* dvb_ringbuffer_reset() counts as read and write operation |
118 | * smp_store_release() to update read pointer | |
119 | */ | |
120 | smp_store_release(&rbuf->pread, 0); | |
121 | /* smp_store_release() to update write pointer */ | |
122 | smp_store_release(&rbuf->pwrite, 0); | |
48c01a9c AO |
123 | rbuf->error = 0; |
124 | } | |
1da177e4 LT |
125 | |
126 | void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf) | |
127 | { | |
afd1a0c9 | 128 | unsigned long flags; |
1da177e4 | 129 | |
afd1a0c9 MCC |
130 | spin_lock_irqsave(&rbuf->lock, flags); |
131 | dvb_ringbuffer_flush(rbuf); | |
132 | spin_unlock_irqrestore(&rbuf->lock, flags); | |
1da177e4 | 133 | |
afd1a0c9 | 134 | wake_up(&rbuf->queue); |
1da177e4 LT |
135 | } |
136 | ||
b0ba0e3a | 137 | ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, u8 __user *buf, size_t len) |
1da177e4 | 138 | { |
afd1a0c9 MCC |
139 | size_t todo = len; |
140 | size_t split; | |
141 | ||
142 | split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0; | |
143 | if (split > 0) { | |
b0ba0e3a AV |
144 | if (copy_to_user(buf, rbuf->data+rbuf->pread, split)) |
145 | return -EFAULT; | |
afd1a0c9 MCC |
146 | buf += split; |
147 | todo -= split; | |
ca6e6126 SM |
148 | /* smp_store_release() for read pointer update to ensure |
149 | * that buf is not overwritten until read is complete, | |
150 | * this pairs with ACCESS_ONCE() in dvb_ringbuffer_free() | |
151 | */ | |
152 | smp_store_release(&rbuf->pread, 0); | |
afd1a0c9 | 153 | } |
b0ba0e3a AV |
154 | if (copy_to_user(buf, rbuf->data+rbuf->pread, todo)) |
155 | return -EFAULT; | |
afd1a0c9 | 156 | |
ca6e6126 SM |
157 | /* smp_store_release() to update read pointer, see above */ |
158 | smp_store_release(&rbuf->pread, (rbuf->pread + todo) % rbuf->size); | |
afd1a0c9 MCC |
159 | |
160 | return len; | |
1da177e4 LT |
161 | } |
162 | ||
b0ba0e3a AV |
163 | void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len) |
164 | { | |
165 | size_t todo = len; | |
166 | size_t split; | |
167 | ||
168 | split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0; | |
169 | if (split > 0) { | |
170 | memcpy(buf, rbuf->data+rbuf->pread, split); | |
171 | buf += split; | |
172 | todo -= split; | |
ca6e6126 SM |
173 | /* smp_store_release() for read pointer update to ensure |
174 | * that buf is not overwritten until read is complete, | |
175 | * this pairs with ACCESS_ONCE() in dvb_ringbuffer_free() | |
176 | */ | |
177 | smp_store_release(&rbuf->pread, 0); | |
b0ba0e3a AV |
178 | } |
179 | memcpy(buf, rbuf->data+rbuf->pread, todo); | |
180 | ||
ca6e6126 SM |
181 | /* smp_store_release() to update read pointer, see above */ |
182 | smp_store_release(&rbuf->pread, (rbuf->pread + todo) % rbuf->size); | |
b0ba0e3a | 183 | } |
1da177e4 LT |
184 | |
185 | ||
186 | ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len) | |
187 | { | |
afd1a0c9 MCC |
188 | size_t todo = len; |
189 | size_t split; | |
1da177e4 | 190 | |
afd1a0c9 | 191 | split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0; |
1da177e4 | 192 | |
afd1a0c9 MCC |
193 | if (split > 0) { |
194 | memcpy(rbuf->data+rbuf->pwrite, buf, split); | |
195 | buf += split; | |
196 | todo -= split; | |
ca6e6126 SM |
197 | /* smp_store_release() for write pointer update to ensure that |
198 | * written data is visible on other cpu cores before the pointer | |
199 | * update, this pairs with smp_load_acquire() in | |
200 | * dvb_ringbuffer_empty() or dvb_ringbuffer_avail() | |
201 | */ | |
202 | smp_store_release(&rbuf->pwrite, 0); | |
afd1a0c9 MCC |
203 | } |
204 | memcpy(rbuf->data+rbuf->pwrite, buf, todo); | |
ca6e6126 SM |
205 | /* smp_store_release() for write pointer update, see above */ |
206 | smp_store_release(&rbuf->pwrite, (rbuf->pwrite + todo) % rbuf->size); | |
1da177e4 | 207 | |
afd1a0c9 | 208 | return len; |
1da177e4 LT |
209 | } |
210 | ||
04da2dae MCC |
211 | ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf, |
212 | const u8 __user *buf, size_t len) | |
213 | { | |
214 | int status; | |
215 | size_t todo = len; | |
216 | size_t split; | |
217 | ||
218 | split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0; | |
219 | ||
220 | if (split > 0) { | |
221 | status = copy_from_user(rbuf->data+rbuf->pwrite, buf, split); | |
222 | if (status) | |
223 | return len - todo; | |
224 | buf += split; | |
225 | todo -= split; | |
ca6e6126 SM |
226 | /* smp_store_release() for write pointer update to ensure that |
227 | * written data is visible on other cpu cores before the pointer | |
228 | * update, this pairs with smp_load_acquire() in | |
229 | * dvb_ringbuffer_empty() or dvb_ringbuffer_avail() | |
230 | */ | |
231 | smp_store_release(&rbuf->pwrite, 0); | |
04da2dae MCC |
232 | } |
233 | status = copy_from_user(rbuf->data+rbuf->pwrite, buf, todo); | |
234 | if (status) | |
235 | return len - todo; | |
ca6e6126 SM |
236 | /* smp_store_release() for write pointer update, see above */ |
237 | smp_store_release(&rbuf->pwrite, (rbuf->pwrite + todo) % rbuf->size); | |
04da2dae MCC |
238 | |
239 | return len; | |
240 | } | |
241 | ||
1da177e4 LT |
242 | ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len) |
243 | { | |
afd1a0c9 MCC |
244 | int status; |
245 | ssize_t oldpwrite = rbuf->pwrite; | |
1da177e4 | 246 | |
afd1a0c9 MCC |
247 | DVB_RINGBUFFER_WRITE_BYTE(rbuf, len >> 8); |
248 | DVB_RINGBUFFER_WRITE_BYTE(rbuf, len & 0xff); | |
249 | DVB_RINGBUFFER_WRITE_BYTE(rbuf, PKT_READY); | |
250 | status = dvb_ringbuffer_write(rbuf, buf, len); | |
1da177e4 | 251 | |
afd1a0c9 MCC |
252 | if (status < 0) rbuf->pwrite = oldpwrite; |
253 | return status; | |
1da177e4 LT |
254 | } |
255 | ||
b0ba0e3a AV |
256 | ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, size_t idx, |
257 | int offset, u8 __user *buf, size_t len) | |
1da177e4 | 258 | { |
afd1a0c9 MCC |
259 | size_t todo; |
260 | size_t split; | |
261 | size_t pktlen; | |
262 | ||
263 | pktlen = rbuf->data[idx] << 8; | |
264 | pktlen |= rbuf->data[(idx + 1) % rbuf->size]; | |
265 | if (offset > pktlen) return -EINVAL; | |
266 | if ((offset + len) > pktlen) len = pktlen - offset; | |
267 | ||
268 | idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size; | |
269 | todo = len; | |
270 | split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0; | |
271 | if (split > 0) { | |
b0ba0e3a AV |
272 | if (copy_to_user(buf, rbuf->data+idx, split)) |
273 | return -EFAULT; | |
afd1a0c9 MCC |
274 | buf += split; |
275 | todo -= split; | |
276 | idx = 0; | |
277 | } | |
b0ba0e3a AV |
278 | if (copy_to_user(buf, rbuf->data+idx, todo)) |
279 | return -EFAULT; | |
280 | ||
281 | return len; | |
282 | } | |
afd1a0c9 | 283 | |
b0ba0e3a AV |
284 | ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx, |
285 | int offset, u8* buf, size_t len) | |
286 | { | |
287 | size_t todo; | |
288 | size_t split; | |
289 | size_t pktlen; | |
290 | ||
291 | pktlen = rbuf->data[idx] << 8; | |
292 | pktlen |= rbuf->data[(idx + 1) % rbuf->size]; | |
293 | if (offset > pktlen) return -EINVAL; | |
294 | if ((offset + len) > pktlen) len = pktlen - offset; | |
295 | ||
296 | idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size; | |
297 | todo = len; | |
298 | split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0; | |
299 | if (split > 0) { | |
300 | memcpy(buf, rbuf->data+idx, split); | |
301 | buf += split; | |
302 | todo -= split; | |
303 | idx = 0; | |
304 | } | |
305 | memcpy(buf, rbuf->data+idx, todo); | |
afd1a0c9 | 306 | return len; |
1da177e4 LT |
307 | } |
308 | ||
309 | void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx) | |
310 | { | |
afd1a0c9 MCC |
311 | size_t pktlen; |
312 | ||
313 | rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED; | |
314 | ||
315 | // clean up disposed packets | |
316 | while(dvb_ringbuffer_avail(rbuf) > DVB_RINGBUFFER_PKTHDRSIZE) { | |
317 | if (DVB_RINGBUFFER_PEEK(rbuf, 2) == PKT_DISPOSED) { | |
50c25fff MK |
318 | pktlen = DVB_RINGBUFFER_PEEK(rbuf, 0) << 8; |
319 | pktlen |= DVB_RINGBUFFER_PEEK(rbuf, 1); | |
320 | DVB_RINGBUFFER_SKIP(rbuf, pktlen + DVB_RINGBUFFER_PKTHDRSIZE); | |
afd1a0c9 | 321 | } else { |
50c25fff MK |
322 | // first packet is not disposed, so we stop cleaning now |
323 | break; | |
afd1a0c9 MCC |
324 | } |
325 | } | |
1da177e4 LT |
326 | } |
327 | ||
328 | ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen) | |
329 | { | |
afd1a0c9 MCC |
330 | int consumed; |
331 | int curpktlen; | |
332 | int curpktstatus; | |
1da177e4 | 333 | |
afd1a0c9 | 334 | if (idx == -1) { |
1da177e4 LT |
335 | idx = rbuf->pread; |
336 | } else { | |
afd1a0c9 MCC |
337 | curpktlen = rbuf->data[idx] << 8; |
338 | curpktlen |= rbuf->data[(idx + 1) % rbuf->size]; | |
339 | idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size; | |
1da177e4 LT |
340 | } |
341 | ||
afd1a0c9 | 342 | consumed = (idx - rbuf->pread) % rbuf->size; |
1da177e4 | 343 | |
afd1a0c9 | 344 | while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) { |
1da177e4 | 345 | |
afd1a0c9 MCC |
346 | curpktlen = rbuf->data[idx] << 8; |
347 | curpktlen |= rbuf->data[(idx + 1) % rbuf->size]; | |
348 | curpktstatus = rbuf->data[(idx + 2) % rbuf->size]; | |
1da177e4 | 349 | |
afd1a0c9 | 350 | if (curpktstatus == PKT_READY) { |
50c25fff MK |
351 | *pktlen = curpktlen; |
352 | return idx; | |
afd1a0c9 | 353 | } |
1da177e4 | 354 | |
afd1a0c9 MCC |
355 | consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE; |
356 | idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size; | |
357 | } | |
1da177e4 | 358 | |
afd1a0c9 MCC |
359 | // no packets available |
360 | return -1; | |
1da177e4 LT |
361 | } |
362 | ||
363 | ||
364 | ||
365 | EXPORT_SYMBOL(dvb_ringbuffer_init); | |
366 | EXPORT_SYMBOL(dvb_ringbuffer_empty); | |
367 | EXPORT_SYMBOL(dvb_ringbuffer_free); | |
368 | EXPORT_SYMBOL(dvb_ringbuffer_avail); | |
1da177e4 | 369 | EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup); |
b0ba0e3a | 370 | EXPORT_SYMBOL(dvb_ringbuffer_read_user); |
1da177e4 LT |
371 | EXPORT_SYMBOL(dvb_ringbuffer_read); |
372 | EXPORT_SYMBOL(dvb_ringbuffer_write); | |
04da2dae | 373 | EXPORT_SYMBOL(dvb_ringbuffer_write_user); |