This source file includes following definitions.
- dvb_ringbuffer_init
- dvb_ringbuffer_empty
- dvb_ringbuffer_free
- dvb_ringbuffer_avail
- dvb_ringbuffer_flush
- dvb_ringbuffer_reset
- dvb_ringbuffer_flush_spinlock_wakeup
- dvb_ringbuffer_read_user
- dvb_ringbuffer_read
- dvb_ringbuffer_write
- dvb_ringbuffer_write_user
- dvb_ringbuffer_pkt_write
- dvb_ringbuffer_pkt_read_user
- dvb_ringbuffer_pkt_read
- dvb_ringbuffer_pkt_dispose
- dvb_ringbuffer_pkt_next
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25 #include <linux/errno.h>
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <linux/sched.h>
29 #include <linux/string.h>
30 #include <linux/uaccess.h>
31
32 #include <media/dvb_ringbuffer.h>
33
34 #define PKT_READY 0
35 #define PKT_DISPOSED 1
36
37
38 void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data, size_t len)
39 {
40 rbuf->pread=rbuf->pwrite=0;
41 rbuf->data=data;
42 rbuf->size=len;
43 rbuf->error=0;
44
45 init_waitqueue_head(&rbuf->queue);
46
47 spin_lock_init(&(rbuf->lock));
48 }
49
50
51
52 int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf)
53 {
54
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56
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58
59
60 return (rbuf->pread == smp_load_acquire(&rbuf->pwrite));
61 }
62
63
64
65 ssize_t dvb_ringbuffer_free(struct dvb_ringbuffer *rbuf)
66 {
67 ssize_t free;
68
69
70
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72
73
74 free = READ_ONCE(rbuf->pread) - rbuf->pwrite;
75 if (free <= 0)
76 free += rbuf->size;
77 return free-1;
78 }
79
80
81
82 ssize_t dvb_ringbuffer_avail(struct dvb_ringbuffer *rbuf)
83 {
84 ssize_t avail;
85
86
87
88
89
90 avail = smp_load_acquire(&rbuf->pwrite) - rbuf->pread;
91 if (avail < 0)
92 avail += rbuf->size;
93 return avail;
94 }
95
96
97
98 void dvb_ringbuffer_flush(struct dvb_ringbuffer *rbuf)
99 {
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101
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103
104
105
106 smp_store_release(&rbuf->pread, smp_load_acquire(&rbuf->pwrite));
107 rbuf->error = 0;
108 }
109 EXPORT_SYMBOL(dvb_ringbuffer_flush);
110
111 void dvb_ringbuffer_reset(struct dvb_ringbuffer *rbuf)
112 {
113
114
115
116 smp_store_release(&rbuf->pread, 0);
117
118 smp_store_release(&rbuf->pwrite, 0);
119 rbuf->error = 0;
120 }
121
122 void dvb_ringbuffer_flush_spinlock_wakeup(struct dvb_ringbuffer *rbuf)
123 {
124 unsigned long flags;
125
126 spin_lock_irqsave(&rbuf->lock, flags);
127 dvb_ringbuffer_flush(rbuf);
128 spin_unlock_irqrestore(&rbuf->lock, flags);
129
130 wake_up(&rbuf->queue);
131 }
132
133 ssize_t dvb_ringbuffer_read_user(struct dvb_ringbuffer *rbuf, u8 __user *buf, size_t len)
134 {
135 size_t todo = len;
136 size_t split;
137
138 split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
139 if (split > 0) {
140 if (copy_to_user(buf, rbuf->data+rbuf->pread, split))
141 return -EFAULT;
142 buf += split;
143 todo -= split;
144
145
146
147
148 smp_store_release(&rbuf->pread, 0);
149 }
150 if (copy_to_user(buf, rbuf->data+rbuf->pread, todo))
151 return -EFAULT;
152
153
154 smp_store_release(&rbuf->pread, (rbuf->pread + todo) % rbuf->size);
155
156 return len;
157 }
158
159 void dvb_ringbuffer_read(struct dvb_ringbuffer *rbuf, u8 *buf, size_t len)
160 {
161 size_t todo = len;
162 size_t split;
163
164 split = (rbuf->pread + len > rbuf->size) ? rbuf->size - rbuf->pread : 0;
165 if (split > 0) {
166 memcpy(buf, rbuf->data+rbuf->pread, split);
167 buf += split;
168 todo -= split;
169
170
171
172
173 smp_store_release(&rbuf->pread, 0);
174 }
175 memcpy(buf, rbuf->data+rbuf->pread, todo);
176
177
178 smp_store_release(&rbuf->pread, (rbuf->pread + todo) % rbuf->size);
179 }
180
181
182 ssize_t dvb_ringbuffer_write(struct dvb_ringbuffer *rbuf, const u8 *buf, size_t len)
183 {
184 size_t todo = len;
185 size_t split;
186
187 split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
188
189 if (split > 0) {
190 memcpy(rbuf->data+rbuf->pwrite, buf, split);
191 buf += split;
192 todo -= split;
193
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196
197
198 smp_store_release(&rbuf->pwrite, 0);
199 }
200 memcpy(rbuf->data+rbuf->pwrite, buf, todo);
201
202 smp_store_release(&rbuf->pwrite, (rbuf->pwrite + todo) % rbuf->size);
203
204 return len;
205 }
206
207 ssize_t dvb_ringbuffer_write_user(struct dvb_ringbuffer *rbuf,
208 const u8 __user *buf, size_t len)
209 {
210 int status;
211 size_t todo = len;
212 size_t split;
213
214 split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0;
215
216 if (split > 0) {
217 status = copy_from_user(rbuf->data+rbuf->pwrite, buf, split);
218 if (status)
219 return len - todo;
220 buf += split;
221 todo -= split;
222
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225
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227 smp_store_release(&rbuf->pwrite, 0);
228 }
229 status = copy_from_user(rbuf->data+rbuf->pwrite, buf, todo);
230 if (status)
231 return len - todo;
232
233 smp_store_release(&rbuf->pwrite, (rbuf->pwrite + todo) % rbuf->size);
234
235 return len;
236 }
237
238 ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len)
239 {
240 int status;
241 ssize_t oldpwrite = rbuf->pwrite;
242
243 DVB_RINGBUFFER_WRITE_BYTE(rbuf, len >> 8);
244 DVB_RINGBUFFER_WRITE_BYTE(rbuf, len & 0xff);
245 DVB_RINGBUFFER_WRITE_BYTE(rbuf, PKT_READY);
246 status = dvb_ringbuffer_write(rbuf, buf, len);
247
248 if (status < 0) rbuf->pwrite = oldpwrite;
249 return status;
250 }
251
252 ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, size_t idx,
253 int offset, u8 __user *buf, size_t len)
254 {
255 size_t todo;
256 size_t split;
257 size_t pktlen;
258
259 pktlen = rbuf->data[idx] << 8;
260 pktlen |= rbuf->data[(idx + 1) % rbuf->size];
261 if (offset > pktlen) return -EINVAL;
262 if ((offset + len) > pktlen) len = pktlen - offset;
263
264 idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
265 todo = len;
266 split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
267 if (split > 0) {
268 if (copy_to_user(buf, rbuf->data+idx, split))
269 return -EFAULT;
270 buf += split;
271 todo -= split;
272 idx = 0;
273 }
274 if (copy_to_user(buf, rbuf->data+idx, todo))
275 return -EFAULT;
276
277 return len;
278 }
279
280 ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx,
281 int offset, u8* buf, size_t len)
282 {
283 size_t todo;
284 size_t split;
285 size_t pktlen;
286
287 pktlen = rbuf->data[idx] << 8;
288 pktlen |= rbuf->data[(idx + 1) % rbuf->size];
289 if (offset > pktlen) return -EINVAL;
290 if ((offset + len) > pktlen) len = pktlen - offset;
291
292 idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size;
293 todo = len;
294 split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0;
295 if (split > 0) {
296 memcpy(buf, rbuf->data+idx, split);
297 buf += split;
298 todo -= split;
299 idx = 0;
300 }
301 memcpy(buf, rbuf->data+idx, todo);
302 return len;
303 }
304
305 void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx)
306 {
307 size_t pktlen;
308
309 rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED;
310
311
312 while(dvb_ringbuffer_avail(rbuf) > DVB_RINGBUFFER_PKTHDRSIZE) {
313 if (DVB_RINGBUFFER_PEEK(rbuf, 2) == PKT_DISPOSED) {
314 pktlen = DVB_RINGBUFFER_PEEK(rbuf, 0) << 8;
315 pktlen |= DVB_RINGBUFFER_PEEK(rbuf, 1);
316 DVB_RINGBUFFER_SKIP(rbuf, pktlen + DVB_RINGBUFFER_PKTHDRSIZE);
317 } else {
318
319 break;
320 }
321 }
322 }
323
324 ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen)
325 {
326 int consumed;
327 int curpktlen;
328 int curpktstatus;
329
330 if (idx == -1) {
331 idx = rbuf->pread;
332 } else {
333 curpktlen = rbuf->data[idx] << 8;
334 curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
335 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
336 }
337
338 consumed = (idx - rbuf->pread) % rbuf->size;
339
340 while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) {
341
342 curpktlen = rbuf->data[idx] << 8;
343 curpktlen |= rbuf->data[(idx + 1) % rbuf->size];
344 curpktstatus = rbuf->data[(idx + 2) % rbuf->size];
345
346 if (curpktstatus == PKT_READY) {
347 *pktlen = curpktlen;
348 return idx;
349 }
350
351 consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE;
352 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
353 }
354
355
356 return -1;
357 }
358
359
360
361 EXPORT_SYMBOL(dvb_ringbuffer_init);
362 EXPORT_SYMBOL(dvb_ringbuffer_empty);
363 EXPORT_SYMBOL(dvb_ringbuffer_free);
364 EXPORT_SYMBOL(dvb_ringbuffer_avail);
365 EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup);
366 EXPORT_SYMBOL(dvb_ringbuffer_read_user);
367 EXPORT_SYMBOL(dvb_ringbuffer_read);
368 EXPORT_SYMBOL(dvb_ringbuffer_write);
369 EXPORT_SYMBOL(dvb_ringbuffer_write_user);