drivers/media/video/videocodec.c

   1 /*
   2  * VIDEO MOTION CODECs internal API for video devices
   3  *
   4  * Interface for MJPEG (and maybe later MPEG/WAVELETS) codec's
   5  * bound to a master device.
   6  *
   7  * (c) 2002 Wolfgang Scherr <scherr@net4you.at>
   8  *
   9  * $Id: videocodec.c,v 1.1.2.8 2003/03/29 07:16:04 rbultje Exp $
  10  *
  11  * ------------------------------------------------------------------------
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  26  *
  27  * ------------------------------------------------------------------------
  28  */
  29
  30 #define VIDEOCODEC_VERSION "v0.2"
  31
  32 #include <linux/kernel.h>
  33 #include <linux/module.h>
  34 #include <linux/init.h>
  35 #include <linux/types.h>
  36 #include <linux/slab.h>
  37
  38 // kernel config is here (procfs flag)
  39 #include <linux/config.h>
  40
  41 #ifdef CONFIG_PROC_FS
  42 #include <linux/proc_fs.h>
  43 #include <asm/uaccess.h>
  44 #endif
  45
  46 #include "videocodec.h"
  47
  48 static int debug = 0;
  49 module_param(debug, int, 0);
  50 MODULE_PARM_DESC(debug, "Debug level (0-4)");
  51
  52 #define dprintk(num, format, args...) \
  53         do { \
  54                 if (debug >= num) \
  55                         printk(format, ##args); \
  56         } while (0)
  57
  58 struct attached_list {
  59         struct videocodec *codec;
  60         struct attached_list *next;
  61 };
  62
  63 struct codec_list {
  64         const struct videocodec *codec;
  65         int attached;
  66         struct attached_list *list;
  67         struct codec_list *next;
  68 };
  69
  70 static struct codec_list *codeclist_top = NULL;
  71
  72 /* ================================================= */
  73 /* function prototypes of the master/slave interface */
  74 /* ================================================= */
  75
  76 struct videocodec *
  77 videocodec_attach (struct videocodec_master *master)
  78 {
  79         struct codec_list *h = codeclist_top;
  80         struct attached_list *a, *ptr;
  81         struct videocodec *codec;
  82         int res;
  83
  84         if (!master) {
  85                 dprintk(1, KERN_ERR "videocodec_attach: no data\n");
  86                 return NULL;
  87         }
  88
  89         dprintk(2,
  90                 "videocodec_attach: '%s', type: %x, flags %lx, magic %lx\n",
  91                 master->name, master->type, master->flags, master->magic);
  92
  93         if (!h) {
  94                 dprintk(1,
  95                         KERN_ERR
  96                         "videocodec_attach: no device available\n");
  97                 return NULL;
  98         }
  99
 100         while (h) {
 101                 // attach only if the slave has at least the flags
 102                 // expected by the master
 103                 if ((master->flags & h->codec->flags) == master->flags) {
 104                         dprintk(4, "videocodec_attach: try '%s'\n",
 105                                 h->codec->name);
 106
 107                         if (!try_module_get(h->codec->owner))
 108                                 return NULL;
 109
 110                         codec =
 111                             kmalloc(sizeof(struct videocodec), GFP_KERNEL);
 112                         if (!codec) {
 113                                 dprintk(1,
 114                                         KERN_ERR
 115                                         "videocodec_attach: no mem\n");
 116                                 goto out_module_put;
 117                         }
 118                         memcpy(codec, h->codec, sizeof(struct videocodec));
 119
 120                         snprintf(codec->name, sizeof(codec->name),
 121                                  "%s[%d]", codec->name, h->attached);
 122                         codec->master_data = master;
 123                         res = codec->setup(codec);
 124                         if (res == 0) {
 125                                 dprintk(3, "videocodec_attach '%s'\n",
 126                                         codec->name);
 127                                 ptr = kzalloc(sizeof(struct attached_list), GFP_KERNEL);
 128                                 if (!ptr) {
 129                                         dprintk(1,
 130                                                 KERN_ERR
 131                                                 "videocodec_attach: no memory\n");
 132                                         goto out_kfree;
 133                                 }
 134                                 ptr->codec = codec;
 135
 136                                 a = h->list;
 137                                 if (!a) {
 138                                         h->list = ptr;
 139                                         dprintk(4,
 140                                                 "videocodec: first element\n");
 141                                 } else {
 142                                         while (a->next)
 143                                                 a = a->next;    // find end
 144                                         a->next = ptr;
 145                                         dprintk(4,
 146                                                 "videocodec: in after '%s'\n",
 147                                                 h->codec->name);
 148                                 }
 149
 150                                 h->attached += 1;
 151                                 return codec;
 152                         } else {
 153                                 kfree(codec);
 154                         }
 155                 }
 156                 h = h->next;
 157         }
 158
 159         dprintk(1, KERN_ERR "videocodec_attach: no codec found!\n");
 160         return NULL;
 161
 162  out_module_put:
 163         module_put(h->codec->owner);
 164  out_kfree:
 165         kfree(codec);
 166         return NULL;
 167 }
 168
 169 int
 170 videocodec_detach (struct videocodec *codec)
 171 {
 172         struct codec_list *h = codeclist_top;
 173         struct attached_list *a, *prev;
 174         int res;
 175
 176         if (!codec) {
 177                 dprintk(1, KERN_ERR "videocodec_detach: no data\n");
 178                 return -EINVAL;
 179         }
 180
 181         dprintk(2,
 182                 "videocodec_detach: '%s', type: %x, flags %lx, magic %lx\n",
 183                 codec->name, codec->type, codec->flags, codec->magic);
 184
 185         if (!h) {
 186                 dprintk(1,
 187                         KERN_ERR "videocodec_detach: no device left...\n");
 188                 return -ENXIO;
 189         }
 190
 191         while (h) {
 192                 a = h->list;
 193                 prev = NULL;
 194                 while (a) {
 195                         if (codec == a->codec) {
 196                                 res = a->codec->unset(a->codec);
 197                                 if (res >= 0) {
 198                                         dprintk(3,
 199                                                 "videocodec_detach: '%s'\n",
 200                                                 a->codec->name);
 201                                         a->codec->master_data = NULL;
 202                                 } else {
 203                                         dprintk(1,
 204                                                 KERN_ERR
 205                                                 "videocodec_detach: '%s'\n",
 206                                                 a->codec->name);
 207                                         a->codec->master_data = NULL;
 208                                 }
 209                                 if (prev == NULL) {
 210                                         h->list = a->next;
 211                                         dprintk(4,
 212                                                 "videocodec: delete first\n");
 213                                 } else {
 214                                         prev->next = a->next;
 215                                         dprintk(4,
 216                                                 "videocodec: delete middle\n");
 217                                 }
 218                                 module_put(a->codec->owner);
 219                                 kfree(a->codec);
 220                                 kfree(a);
 221                                 h->attached -= 1;
 222                                 return 0;
 223                         }
 224                         prev = a;
 225                         a = a->next;
 226                 }
 227                 h = h->next;
 228         }
 229
 230         dprintk(1, KERN_ERR "videocodec_detach: given codec not found!\n");
 231         return -EINVAL;
 232 }
 233
 234 int
 235 videocodec_register (const struct videocodec *codec)
 236 {
 237         struct codec_list *ptr, *h = codeclist_top;
 238
 239         if (!codec) {
 240                 dprintk(1, KERN_ERR "videocodec_register: no data!\n");
 241                 return -EINVAL;
 242         }
 243
 244         dprintk(2,
 245                 "videocodec: register '%s', type: %x, flags %lx, magic %lx\n",
 246                 codec->name, codec->type, codec->flags, codec->magic);
 247
 248         ptr = kzalloc(sizeof(struct codec_list), GFP_KERNEL);
 249         if (!ptr) {
 250                 dprintk(1, KERN_ERR "videocodec_register: no memory\n");
 251                 return -ENOMEM;
 252         }
 253         ptr->codec = codec;
 254
 255         if (!h) {
 256                 codeclist_top = ptr;
 257                 dprintk(4, "videocodec: hooked in as first element\n");
 258         } else {
 259                 while (h->next)
 260                         h = h->next;    // find the end
 261                 h->next = ptr;
 262                 dprintk(4, "videocodec: hooked in after '%s'\n",
 263                         h->codec->name);
 264         }
 265
 266         return 0;
 267 }
 268
 269 int
 270 videocodec_unregister (const struct videocodec *codec)
 271 {
 272         struct codec_list *prev = NULL, *h = codeclist_top;
 273
 274         if (!codec) {
 275                 dprintk(1, KERN_ERR "videocodec_unregister: no data!\n");
 276                 return -EINVAL;
 277         }
 278
 279         dprintk(2,
 280                 "videocodec: unregister '%s', type: %x, flags %lx, magic %lx\n",
 281                 codec->name, codec->type, codec->flags, codec->magic);
 282
 283         if (!h) {
 284                 dprintk(1,
 285                         KERN_ERR
 286                         "videocodec_unregister: no device left...\n");
 287                 return -ENXIO;
 288         }
 289
 290         while (h) {
 291                 if (codec == h->codec) {
 292                         if (h->attached) {
 293                                 dprintk(1,
 294                                         KERN_ERR
 295                                         "videocodec: '%s' is used\n",
 296                                         h->codec->name);
 297                                 return -EBUSY;
 298                         }
 299                         dprintk(3, "videocodec: unregister '%s' is ok.\n",
 300                                 h->codec->name);
 301                         if (prev == NULL) {
 302                                 codeclist_top = h->next;
 303                                 dprintk(4,
 304                                         "videocodec: delete first element\n");
 305                         } else {
 306                                 prev->next = h->next;
 307                                 dprintk(4,
 308                                         "videocodec: delete middle element\n");
 309                         }
 310                         kfree(h);
 311                         return 0;
 312                 }
 313                 prev = h;
 314                 h = h->next;
 315         }
 316
 317         dprintk(1,
 318                 KERN_ERR
 319                 "videocodec_unregister: given codec not found!\n");
 320         return -EINVAL;
 321 }
 322
 323 #ifdef CONFIG_PROC_FS
 324 /* ============ */
 325 /* procfs stuff */
 326 /* ============ */
 327
 328 static char *videocodec_buf = NULL;
 329 static int videocodec_bufsize = 0;
 330
 331 static int
 332 videocodec_build_table (void)
 333 {
 334         struct codec_list *h = codeclist_top;
 335         struct attached_list *a;
 336         int i = 0, size;
 337
 338         // sum up amount of slaves plus their attached masters
 339         while (h) {
 340                 i += h->attached + 1;
 341                 h = h->next;
 342         }
 343 #define LINESIZE 100
 344         size = LINESIZE * (i + 1);
 345
 346         dprintk(3, "videocodec_build table: %d entries, %d bytes\n", i,
 347                 size);
 348
 349         kfree(videocodec_buf);
 350         videocodec_buf = (char *) kmalloc(size, GFP_KERNEL);
 351
 352         i = 0;
 353         i += scnprintf(videocodec_buf + i, size - 1,
 354                       "<S>lave or attached <M>aster name  type flags    magic    ");
 355         i += scnprintf(videocodec_buf + i, size -i - 1, "(connected as)\n");
 356
 357         h = codeclist_top;
 358         while (h) {
 359                 if (i > (size - LINESIZE))
 360                         break;  // security check
 361                 i += scnprintf(videocodec_buf + i, size -i -1,
 362                               "S %32s %04x %08lx %08lx (TEMPLATE)\n",
 363                               h->codec->name, h->codec->type,
 364                               h->codec->flags, h->codec->magic);
 365                 a = h->list;
 366                 while (a) {
 367                         if (i > (size - LINESIZE))
 368                                 break;  // security check
 369                         i += scnprintf(videocodec_buf + i, size -i -1,
 370                                       "M %32s %04x %08lx %08lx (%s)\n",
 371                                       a->codec->master_data->name,
 372                                       a->codec->master_data->type,
 373                                       a->codec->master_data->flags,
 374                                       a->codec->master_data->magic,
 375                                       a->codec->name);
 376                         a = a->next;
 377                 }
 378                 h = h->next;
 379         }
 380
 381         return i;
 382 }
 383
 384 //The definition:
 385 //typedef int (read_proc_t)(char *page, char **start, off_t off,
 386 //                          int count, int *eof, void *data);
 387
 388 static int
 389 videocodec_info (char  *buffer,
 390                  char **buffer_location,
 391                  off_t  offset,
 392                  int    buffer_length,
 393                  int   *eof,
 394                  void  *data)
 395 {
 396         int size;
 397
 398         dprintk(3, "videocodec_info: offset: %ld, len %d / size %d\n",
 399                 offset, buffer_length, videocodec_bufsize);
 400
 401         if (offset == 0) {
 402                 videocodec_bufsize = videocodec_build_table();
 403         }
 404         if ((offset < 0) || (offset >= videocodec_bufsize)) {
 405                 dprintk(4,
 406                         "videocodec_info: call delivers no result, return 0\n");
 407                 *eof = 1;
 408                 return 0;
 409         }
 410
 411         if (buffer_length < (videocodec_bufsize - offset)) {
 412                 dprintk(4, "videocodec_info: %ld needed, %d got\n",
 413                         videocodec_bufsize - offset, buffer_length);
 414                 size = buffer_length;
 415         } else {
 416                 dprintk(4, "videocodec_info: last reading of %ld bytes\n",
 417                         videocodec_bufsize - offset);
 418                 size = videocodec_bufsize - offset;
 419                 *eof = 1;
 420         }
 421
 422         memcpy(buffer, videocodec_buf + offset, size);
 423         /* doesn't work...                           */
 424         /* copy_to_user(buffer, videocodec_buf+offset, size); */
 425         /* *buffer_location = videocodec_buf+offset; */
 426
 427         return size;
 428 }
 429 #endif
 430
 431 /* ===================== */
 432 /* hook in driver module */
 433 /* ===================== */
 434 static int __init
 435 videocodec_init (void)
 436 {
 437 #ifdef CONFIG_PROC_FS
 438         static struct proc_dir_entry *videocodec_proc_entry;
 439 #endif
 440
 441         printk(KERN_INFO "Linux video codec intermediate layer: %s\n",
 442                VIDEOCODEC_VERSION);
 443
 444 #ifdef CONFIG_PROC_FS
 445         videocodec_buf = NULL;
 446         videocodec_bufsize = 0;
 447
 448         videocodec_proc_entry = create_proc_entry("videocodecs", 0, NULL);
 449         if (videocodec_proc_entry) {
 450                 videocodec_proc_entry->read_proc = videocodec_info;
 451                 videocodec_proc_entry->write_proc = NULL;
 452                 videocodec_proc_entry->data = NULL;
 453                 videocodec_proc_entry->owner = THIS_MODULE;
 454         } else {
 455                 dprintk(1, KERN_ERR "videocodec: can't init procfs.\n");
 456         }
 457 #endif
 458         return 0;
 459 }
 460
 461 static void __exit
 462 videocodec_exit (void)
 463 {
 464 #ifdef CONFIG_PROC_FS
 465         remove_proc_entry("videocodecs", NULL);
 466         kfree(videocodec_buf);
 467 #endif
 468 }
 469
 470 EXPORT_SYMBOL(videocodec_attach);
 471 EXPORT_SYMBOL(videocodec_detach);
 472 EXPORT_SYMBOL(videocodec_register);
 473 EXPORT_SYMBOL(videocodec_unregister);
 474
 475 module_init(videocodec_init);
 476 module_exit(videocodec_exit);
 477
 478 MODULE_AUTHOR("Wolfgang Scherr <scherr@net4you.at>");
 479 MODULE_DESCRIPTION("Intermediate API module for video codecs "
 480                    VIDEOCODEC_VERSION);
 481 MODULE_LICENSE("GPL");