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_write_user(struct dvb_ringbuffer *rbuf, 170 const u8 __user *buf, size_t len) 171 { 172 int status; 173 size_t todo = len; 174 size_t split; 175 176 split = (rbuf->pwrite + len > rbuf->size) ? rbuf->size - rbuf->pwrite : 0; 177 178 if (split > 0) { 179 status = copy_from_user(rbuf->data+rbuf->pwrite, buf, split); 180 if (status) 181 return len - todo; 182 buf += split; 183 todo -= split; 184 rbuf->pwrite = 0; 185 } 186 status = copy_from_user(rbuf->data+rbuf->pwrite, buf, todo); 187 if (status) 188 return len - todo; 189 rbuf->pwrite = (rbuf->pwrite + todo) % rbuf->size; 190 191 return len; 192 } 193 194 ssize_t dvb_ringbuffer_pkt_write(struct dvb_ringbuffer *rbuf, u8* buf, size_t len) 195 { 196 int status; 197 ssize_t oldpwrite = rbuf->pwrite; 198 199 DVB_RINGBUFFER_WRITE_BYTE(rbuf, len >> 8); 200 DVB_RINGBUFFER_WRITE_BYTE(rbuf, len & 0xff); 201 DVB_RINGBUFFER_WRITE_BYTE(rbuf, PKT_READY); 202 status = dvb_ringbuffer_write(rbuf, buf, len); 203 204 if (status < 0) rbuf->pwrite = oldpwrite; 205 return status; 206 } 207 208 ssize_t dvb_ringbuffer_pkt_read_user(struct dvb_ringbuffer *rbuf, size_t idx, 209 int offset, u8 __user *buf, size_t len) 210 { 211 size_t todo; 212 size_t split; 213 size_t pktlen; 214 215 pktlen = rbuf->data[idx] << 8; 216 pktlen |= rbuf->data[(idx + 1) % rbuf->size]; 217 if (offset > pktlen) return -EINVAL; 218 if ((offset + len) > pktlen) len = pktlen - offset; 219 220 idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size; 221 todo = len; 222 split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0; 223 if (split > 0) { 224 if (copy_to_user(buf, rbuf->data+idx, split)) 225 return -EFAULT; 226 buf += split; 227 todo -= split; 228 idx = 0; 229 } 230 if (copy_to_user(buf, rbuf->data+idx, todo)) 231 return -EFAULT; 232 233 return len; 234 } 235 236 ssize_t dvb_ringbuffer_pkt_read(struct dvb_ringbuffer *rbuf, size_t idx, 237 int offset, u8* buf, size_t len) 238 { 239 size_t todo; 240 size_t split; 241 size_t pktlen; 242 243 pktlen = rbuf->data[idx] << 8; 244 pktlen |= rbuf->data[(idx + 1) % rbuf->size]; 245 if (offset > pktlen) return -EINVAL; 246 if ((offset + len) > pktlen) len = pktlen - offset; 247 248 idx = (idx + DVB_RINGBUFFER_PKTHDRSIZE + offset) % rbuf->size; 249 todo = len; 250 split = ((idx + len) > rbuf->size) ? rbuf->size - idx : 0; 251 if (split > 0) { 252 memcpy(buf, rbuf->data+idx, split); 253 buf += split; 254 todo -= split; 255 idx = 0; 256 } 257 memcpy(buf, rbuf->data+idx, todo); 258 return len; 259 } 260 261 void dvb_ringbuffer_pkt_dispose(struct dvb_ringbuffer *rbuf, size_t idx) 262 { 263 size_t pktlen; 264 265 rbuf->data[(idx + 2) % rbuf->size] = PKT_DISPOSED; 266 267 // clean up disposed packets 268 while(dvb_ringbuffer_avail(rbuf) > DVB_RINGBUFFER_PKTHDRSIZE) { 269 if (DVB_RINGBUFFER_PEEK(rbuf, 2) == PKT_DISPOSED) { 270 pktlen = DVB_RINGBUFFER_PEEK(rbuf, 0) << 8; 271 pktlen |= DVB_RINGBUFFER_PEEK(rbuf, 1); 272 DVB_RINGBUFFER_SKIP(rbuf, pktlen + DVB_RINGBUFFER_PKTHDRSIZE); 273 } else { 274 // first packet is not disposed, so we stop cleaning now 275 break; 276 } 277 } 278 } 279 280 ssize_t dvb_ringbuffer_pkt_next(struct dvb_ringbuffer *rbuf, size_t idx, size_t* pktlen) 281 { 282 int consumed; 283 int curpktlen; 284 int curpktstatus; 285 286 if (idx == -1) { 287 idx = rbuf->pread; 288 } else { 289 curpktlen = rbuf->data[idx] << 8; 290 curpktlen |= rbuf->data[(idx + 1) % rbuf->size]; 291 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size; 292 } 293 294 consumed = (idx - rbuf->pread) % rbuf->size; 295 296 while((dvb_ringbuffer_avail(rbuf) - consumed) > DVB_RINGBUFFER_PKTHDRSIZE) { 297 298 curpktlen = rbuf->data[idx] << 8; 299 curpktlen |= rbuf->data[(idx + 1) % rbuf->size]; 300 curpktstatus = rbuf->data[(idx + 2) % rbuf->size]; 301 302 if (curpktstatus == PKT_READY) { 303 *pktlen = curpktlen; 304 return idx; 305 } 306 307 consumed += curpktlen + DVB_RINGBUFFER_PKTHDRSIZE; 308 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size; 309 } 310 311 // no packets available 312 return -1; 313 } 314 315 316 317 EXPORT_SYMBOL(dvb_ringbuffer_init); 318 EXPORT_SYMBOL(dvb_ringbuffer_empty); 319 EXPORT_SYMBOL(dvb_ringbuffer_free); 320 EXPORT_SYMBOL(dvb_ringbuffer_avail); 321 EXPORT_SYMBOL(dvb_ringbuffer_flush_spinlock_wakeup); 322 EXPORT_SYMBOL(dvb_ringbuffer_read_user); 323 EXPORT_SYMBOL(dvb_ringbuffer_read); 324 EXPORT_SYMBOL(dvb_ringbuffer_write); 325 EXPORT_SYMBOL(dvb_ringbuffer_write_user); 326