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 1.1.1.1 2007/08/03 18:52:40 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
47static int debug = 0;
48module_param(debug, int, 0);
49MODULE_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
57struct attached_list {
58	struct videocodec *codec;
59	struct attached_list *next;
60};
61
62struct codec_list {
63	const struct videocodec *codec;
64	int attached;
65	struct attached_list *list;
66	struct codec_list *next;
67};
68
69static struct codec_list *codeclist_top = NULL;
70
71/* ================================================= */
72/* function prototypes of the master/slave interface */
73/* ================================================= */
74
75struct videocodec *
76videocodec_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
168int
169videocodec_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
233int
234videocodec_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
268int
269videocodec_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
327static char *videocodec_buf = NULL;
328static int videocodec_bufsize = 0;
329
330static int
331videocodec_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 = kmalloc(size, GFP_KERNEL);
350
351	if (!videocodec_buf)
352		return 0;
353
354	i = 0;
355	i += scnprintf(videocodec_buf + i, size - 1,
356		      "<S>lave or attached <M>aster name  type flags    magic    ");
357	i += scnprintf(videocodec_buf + i, size -i - 1, "(connected as)\n");
358
359	h = codeclist_top;
360	while (h) {
361		if (i > (size - LINESIZE))
362			break;	// security check
363		i += scnprintf(videocodec_buf + i, size -i -1,
364			      "S %32s %04x %08lx %08lx (TEMPLATE)\n",
365			      h->codec->name, h->codec->type,
366			      h->codec->flags, h->codec->magic);
367		a = h->list;
368		while (a) {
369			if (i > (size - LINESIZE))
370				break;	// security check
371			i += scnprintf(videocodec_buf + i, size -i -1,
372				      "M %32s %04x %08lx %08lx (%s)\n",
373				      a->codec->master_data->name,
374				      a->codec->master_data->type,
375				      a->codec->master_data->flags,
376				      a->codec->master_data->magic,
377				      a->codec->name);
378			a = a->next;
379		}
380		h = h->next;
381	}
382
383	return i;
384}
385
386//The definition:
387//typedef int (read_proc_t)(char *page, char **start, off_t off,
388//                          int count, int *eof, void *data);
389
390static int
391videocodec_info (char  *buffer,
392		 char **buffer_location,
393		 off_t  offset,
394		 int    buffer_length,
395		 int   *eof,
396		 void  *data)
397{
398	int size;
399
400	dprintk(3, "videocodec_info: offset: %ld, len %d / size %d\n",
401		offset, buffer_length, videocodec_bufsize);
402
403	if (offset == 0) {
404		videocodec_bufsize = videocodec_build_table();
405	}
406	if ((offset < 0) || (offset >= videocodec_bufsize)) {
407		dprintk(4,
408			"videocodec_info: call delivers no result, return 0\n");
409		*eof = 1;
410		return 0;
411	}
412
413	if (buffer_length < (videocodec_bufsize - offset)) {
414		dprintk(4, "videocodec_info: %ld needed, %d got\n",
415			videocodec_bufsize - offset, buffer_length);
416		size = buffer_length;
417	} else {
418		dprintk(4, "videocodec_info: last reading of %ld bytes\n",
419			videocodec_bufsize - offset);
420		size = videocodec_bufsize - offset;
421		*eof = 1;
422	}
423
424	memcpy(buffer, videocodec_buf + offset, size);
425	/* doesn't work...                           */
426	/* copy_to_user(buffer, videocodec_buf+offset, size); */
427	/* *buffer_location = videocodec_buf+offset; */
428
429	return size;
430}
431#endif
432
433/* ===================== */
434/* hook in driver module */
435/* ===================== */
436static int __init
437videocodec_init (void)
438{
439#ifdef CONFIG_PROC_FS
440	static struct proc_dir_entry *videocodec_proc_entry;
441#endif
442
443	printk(KERN_INFO "Linux video codec intermediate layer: %s\n",
444	       VIDEOCODEC_VERSION);
445
446#ifdef CONFIG_PROC_FS
447	videocodec_buf = NULL;
448	videocodec_bufsize = 0;
449
450	videocodec_proc_entry = create_proc_entry("videocodecs", 0, NULL);
451	if (videocodec_proc_entry) {
452		videocodec_proc_entry->read_proc = videocodec_info;
453		videocodec_proc_entry->write_proc = NULL;
454		videocodec_proc_entry->data = NULL;
455		videocodec_proc_entry->owner = THIS_MODULE;
456	} else {
457		dprintk(1, KERN_ERR "videocodec: can't init procfs.\n");
458	}
459#endif
460	return 0;
461}
462
463static void __exit
464videocodec_exit (void)
465{
466#ifdef CONFIG_PROC_FS
467	remove_proc_entry("videocodecs", NULL);
468	kfree(videocodec_buf);
469#endif
470}
471
472EXPORT_SYMBOL(videocodec_attach);
473EXPORT_SYMBOL(videocodec_detach);
474EXPORT_SYMBOL(videocodec_register);
475EXPORT_SYMBOL(videocodec_unregister);
476
477module_init(videocodec_init);
478module_exit(videocodec_exit);
479
480MODULE_AUTHOR("Wolfgang Scherr <scherr@net4you.at>");
481MODULE_DESCRIPTION("Intermediate API module for video codecs "
482		   VIDEOCODEC_VERSION);
483MODULE_LICENSE("GPL");
484