Merge rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[linux-2.6] / 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");