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 = (struct attached_list *)
 128                                     kmalloc(sizeof(struct attached_list),
 129                                             GFP_KERNEL);
 130                                 if (!ptr) {
 131                                         dprintk(1,
 132                                                 KERN_ERR
 133                                                 "videocodec_attach: no memory\n");
 134                                         goto out_kfree;
 135                                 }
 136                                 memset(ptr, 0,
 137                                        sizeof(struct attached_list));
 138                                 ptr->codec = codec;
 139
 140                                 a = h->list;
 141                                 if (!a) {
 142                                         h->list = ptr;
 143                                         dprintk(4,
 144                                                 "videocodec: first element\n");
 145                                 } else {
 146                                         while (a->next)
 147                                                 a = a->next;    // find end
 148                                         a->next = ptr;
 149                                         dprintk(4,
 150                                                 "videocodec: in after '%s'\n",
 151                                                 h->codec->name);
 152                                 }
 153
 154                                 h->attached += 1;
 155                                 return codec;
 156                         } else {
 157                                 kfree(codec);
 158                         }
 159                 }
 160                 h = h->next;
 161         }
 162
 163         dprintk(1, KERN_ERR "videocodec_attach: no codec found!\n");
 164         return NULL;
 165
 166  out_module_put:
 167         module_put(h->codec->owner);
 168  out_kfree:
 169         kfree(codec);
 170         return NULL;
 171 }
 172
 173 int
 174 videocodec_detach (struct videocodec *codec)
 175 {
 176         struct codec_list *h = codeclist_top;
 177         struct attached_list *a, *prev;
 178         int res;
 179
 180         if (!codec) {
 181                 dprintk(1, KERN_ERR "videocodec_detach: no data\n");
 182                 return -EINVAL;
 183         }
 184
 185         dprintk(2,
 186                 "videocodec_detach: '%s', type: %x, flags %lx, magic %lx\n",
 187                 codec->name, codec->type, codec->flags, codec->magic);
 188
 189         if (!h) {
 190                 dprintk(1,
 191                         KERN_ERR "videocodec_detach: no device left...\n");
 192                 return -ENXIO;
 193         }
 194
 195         while (h) {
 196                 a = h->list;
 197                 prev = NULL;
 198                 while (a) {
 199                         if (codec == a->codec) {
 200                                 res = a->codec->unset(a->codec);
 201                                 if (res >= 0) {
 202                                         dprintk(3,
 203                                                 "videocodec_detach: '%s'\n",
 204                                                 a->codec->name);
 205                                         a->codec->master_data = NULL;
 206                                 } else {
 207                                         dprintk(1,
 208                                                 KERN_ERR
 209                                                 "videocodec_detach: '%s'\n",
 210                                                 a->codec->name);
 211                                         a->codec->master_data = NULL;
 212                                 }
 213                                 if (prev == NULL) {
 214                                         h->list = a->next;
 215                                         dprintk(4,
 216                                                 "videocodec: delete first\n");
 217                                 } else {
 218                                         prev->next = a->next;
 219                                         dprintk(4,
 220                                                 "videocodec: delete middle\n");
 221                                 }
 222                                 module_put(a->codec->owner);
 223                                 kfree(a->codec);
 224                                 kfree(a);
 225                                 h->attached -= 1;
 226                                 return 0;
 227                         }
 228                         prev = a;
 229                         a = a->next;
 230                 }
 231                 h = h->next;
 232         }
 233
 234         dprintk(1, KERN_ERR "videocodec_detach: given codec not found!\n");
 235         return -EINVAL;
 236 }
 237
 238 int
 239 videocodec_register (const struct videocodec *codec)
 240 {
 241         struct codec_list *ptr, *h = codeclist_top;
 242
 243         if (!codec) {
 244                 dprintk(1, KERN_ERR "videocodec_register: no data!\n");
 245                 return -EINVAL;
 246         }
 247
 248         dprintk(2,
 249                 "videocodec: register '%s', type: %x, flags %lx, magic %lx\n",
 250                 codec->name, codec->type, codec->flags, codec->magic);
 251
 252         ptr =
 253             (struct codec_list *) kmalloc(sizeof(struct codec_list),
 254                                           GFP_KERNEL);
 255         if (!ptr) {
 256                 dprintk(1, KERN_ERR "videocodec_register: no memory\n");
 257                 return -ENOMEM;
 258         }
 259         memset(ptr, 0, sizeof(struct codec_list));
 260         ptr->codec = codec;
 261
 262         if (!h) {
 263                 codeclist_top = ptr;
 264                 dprintk(4, "videocodec: hooked in as first element\n");
 265         } else {
 266                 while (h->next)
 267                         h = h->next;    // find the end
 268                 h->next = ptr;
 269                 dprintk(4, "videocodec: hooked in after '%s'\n",
 270                         h->codec->name);
 271         }
 272
 273         return 0;
 274 }
 275
 276 int
 277 videocodec_unregister (const struct videocodec *codec)
 278 {
 279         struct codec_list *prev = NULL, *h = codeclist_top;
 280
 281         if (!codec) {
 282                 dprintk(1, KERN_ERR "videocodec_unregister: no data!\n");
 283                 return -EINVAL;
 284         }
 285
 286         dprintk(2,
 287                 "videocodec: unregister '%s', type: %x, flags %lx, magic %lx\n",
 288                 codec->name, codec->type, codec->flags, codec->magic);
 289
 290         if (!h) {
 291                 dprintk(1,
 292                         KERN_ERR
 293                         "videocodec_unregister: no device left...\n");
 294                 return -ENXIO;
 295         }
 296
 297         while (h) {
 298                 if (codec == h->codec) {
 299                         if (h->attached) {
 300                                 dprintk(1,
 301                                         KERN_ERR
 302                                         "videocodec: '%s' is used\n",
 303                                         h->codec->name);
 304                                 return -EBUSY;
 305                         }
 306                         dprintk(3, "videocodec: unregister '%s' is ok.\n",
 307                                 h->codec->name);
 308                         if (prev == NULL) {
 309                                 codeclist_top = h->next;
 310                                 dprintk(4,
 311                                         "videocodec: delete first element\n");
 312                         } else {
 313                                 prev->next = h->next;
 314                                 dprintk(4,
 315                                         "videocodec: delete middle element\n");
 316                         }
 317                         kfree(h);
 318                         return 0;
 319                 }
 320                 prev = h;
 321                 h = h->next;
 322         }
 323
 324         dprintk(1,
 325                 KERN_ERR
 326                 "videocodec_unregister: given codec not found!\n");
 327         return -EINVAL;
 328 }
 329
 330 #ifdef CONFIG_PROC_FS
 331 /* ============ */
 332 /* procfs stuff */
 333 /* ============ */
 334
 335 static char *videocodec_buf = NULL;
 336 static int videocodec_bufsize = 0;
 337
 338 static int
 339 videocodec_build_table (void)
 340 {
 341         struct codec_list *h = codeclist_top;
 342         struct attached_list *a;
 343         int i = 0, size;
 344
 345         // sum up amount of slaves plus their attached masters
 346         while (h) {
 347                 i += h->attached + 1;
 348                 h = h->next;
 349         }
 350 #define LINESIZE 100
 351         size = LINESIZE * (i + 1);
 352
 353         dprintk(3, "videocodec_build table: %d entries, %d bytes\n", i,
 354                 size);
 355
 356         if (videocodec_buf)
 357                 kfree(videocodec_buf);
 358         videocodec_buf = (char *) kmalloc(size, GFP_KERNEL);
 359
 360         i = 0;
 361         i += scnprintf(videocodec_buf + i, size - 1,
 362                       "<S>lave or attached <M>aster name  type flags    magic    ");
 363         i += scnprintf(videocodec_buf + i, size -i - 1, "(connected as)\n");
 364
 365         h = codeclist_top;
 366         while (h) {
 367                 if (i > (size - LINESIZE))
 368                         break;  // security check
 369                 i += scnprintf(videocodec_buf + i, size -i -1,
 370                               "S %32s %04x %08lx %08lx (TEMPLATE)\n",
 371                               h->codec->name, h->codec->type,
 372                               h->codec->flags, h->codec->magic);
 373                 a = h->list;
 374                 while (a) {
 375                         if (i > (size - LINESIZE))
 376                                 break;  // security check
 377                         i += scnprintf(videocodec_buf + i, size -i -1,
 378                                       "M %32s %04x %08lx %08lx (%s)\n",
 379                                       a->codec->master_data->name,
 380                                       a->codec->master_data->type,
 381                                       a->codec->master_data->flags,
 382                                       a->codec->master_data->magic,
 383                                       a->codec->name);
 384                         a = a->next;
 385                 }
 386                 h = h->next;
 387         }
 388
 389         return i;
 390 }
 391
 392 //The definition:
 393 //typedef int (read_proc_t)(char *page, char **start, off_t off,
 394 //                          int count, int *eof, void *data);
 395
 396 static int
 397 videocodec_info (char  *buffer,
 398                  char **buffer_location,
 399                  off_t  offset,
 400                  int    buffer_length,
 401                  int   *eof,
 402                  void  *data)
 403 {
 404         int size;
 405
 406         dprintk(3, "videocodec_info: offset: %ld, len %d / size %d\n",
 407                 offset, buffer_length, videocodec_bufsize);
 408
 409         if (offset == 0) {
 410                 videocodec_bufsize = videocodec_build_table();
 411         }
 412         if ((offset < 0) || (offset >= videocodec_bufsize)) {
 413                 dprintk(4,
 414                         "videocodec_info: call delivers no result, return 0\n");
 415                 *eof = 1;
 416                 return 0;
 417         }
 418
 419         if (buffer_length < (videocodec_bufsize - offset)) {
 420                 dprintk(4, "videocodec_info: %ld needed, %d got\n",
 421                         videocodec_bufsize - offset, buffer_length);
 422                 size = buffer_length;
 423         } else {
 424                 dprintk(4, "videocodec_info: last reading of %ld bytes\n",
 425                         videocodec_bufsize - offset);
 426                 size = videocodec_bufsize - offset;
 427                 *eof = 1;
 428         }
 429
 430         memcpy(buffer, videocodec_buf + offset, size);
 431         /* doesn't work...                           */
 432         /* copy_to_user(buffer, videocodec_buf+offset, size); */
 433         /* *buffer_location = videocodec_buf+offset; */
 434
 435         return size;
 436 }
 437 #endif
 438
 439 /* ===================== */
 440 /* hook in driver module */
 441 /* ===================== */
 442 static int __init
 443 videocodec_init (void)
 444 {
 445 #ifdef CONFIG_PROC_FS
 446         static struct proc_dir_entry *videocodec_proc_entry;
 447 #endif
 448
 449         printk(KERN_INFO "Linux video codec intermediate layer: %s\n",
 450                VIDEOCODEC_VERSION);
 451
 452 #ifdef CONFIG_PROC_FS
 453         videocodec_buf = NULL;
 454         videocodec_bufsize = 0;
 455
 456         videocodec_proc_entry = create_proc_entry("videocodecs", 0, NULL);
 457         if (videocodec_proc_entry) {
 458                 videocodec_proc_entry->read_proc = videocodec_info;
 459                 videocodec_proc_entry->write_proc = NULL;
 460                 videocodec_proc_entry->data = NULL;
 461                 videocodec_proc_entry->owner = THIS_MODULE;
 462         } else {
 463                 dprintk(1, KERN_ERR "videocodec: can't init procfs.\n");
 464         }
 465 #endif
 466         return 0;
 467 }
 468
 469 static void __exit
 470 videocodec_exit (void)
 471 {
 472 #ifdef CONFIG_PROC_FS
 473         remove_proc_entry("videocodecs", NULL);
 474         if (videocodec_buf)
 475                 kfree(videocodec_buf);
 476 #endif
 477 }
 478
 479 EXPORT_SYMBOL(videocodec_attach);
 480 EXPORT_SYMBOL(videocodec_detach);
 481 EXPORT_SYMBOL(videocodec_register);
 482 EXPORT_SYMBOL(videocodec_unregister);
 483
 484 module_init(videocodec_init);
 485 module_exit(videocodec_exit);
 486
 487 MODULE_AUTHOR("Wolfgang Scherr <scherr@net4you.at>");
 488 MODULE_DESCRIPTION("Intermediate API module for video codecs "
 489                    VIDEOCODEC_VERSION);
 490 MODULE_LICENSE("GPL");