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