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 <linux/seq_file.h>
43#include <asm/uaccess.h>
44#endif
45
46#include "videocodec.h"
47
48static int debug;
49module_param(debug, int, 0);
50MODULE_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
58struct attached_list {
59	struct videocodec *codec;
60	struct attached_list *next;
61};
62
63struct codec_list {
64	const struct videocodec *codec;
65	int attached;
66	struct attached_list *list;
67	struct codec_list *next;
68};
69
70static struct codec_list *codeclist_top = NULL;
71
72/* ================================================= */
73/* function prototypes of the master/slave interface */
74/* ================================================= */
75
76struct videocodec *
77videocodec_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', flags %lx, magic %lx\n",
91		master->name, 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 = kmemdup(h->codec, sizeof(struct videocodec),
111					GFP_KERNEL);
112			if (!codec) {
113				dprintk(1,
114					KERN_ERR
115					"videocodec_attach: no mem\n");
116				goto out_module_put;
117			}
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
323static int proc_videocodecs_show(struct seq_file *m, void *v)
324{
325	struct codec_list *h = codeclist_top;
326	struct attached_list *a;
327
328	seq_printf(m, "<S>lave or attached <M>aster name  type flags    magic    ");
329	seq_printf(m, "(connected as)\n");
330
331	h = codeclist_top;
332	while (h) {
333		seq_printf(m, "S %32s %04x %08lx %08lx (TEMPLATE)\n",
334			      h->codec->name, h->codec->type,
335			      h->codec->flags, h->codec->magic);
336		a = h->list;
337		while (a) {
338			seq_printf(m, "M %32s %04x %08lx %08lx (%s)\n",
339				      a->codec->master_data->name,
340				      a->codec->master_data->type,
341				      a->codec->master_data->flags,
342				      a->codec->master_data->magic,
343				      a->codec->name);
344			a = a->next;
345		}
346		h = h->next;
347	}
348
349	return 0;
350}
351
352static int proc_videocodecs_open(struct inode *inode, struct file *file)
353{
354	return single_open(file, proc_videocodecs_show, NULL);
355}
356
357static const struct file_operations videocodecs_proc_fops = {
358	.owner		= THIS_MODULE,
359	.open		= proc_videocodecs_open,
360	.read		= seq_read,
361	.llseek		= seq_lseek,
362	.release	= single_release,
363};
364#endif
365
366/* ===================== */
367/* hook in driver module */
368/* ===================== */
369static int __init
370videocodec_init (void)
371{
372#ifdef CONFIG_PROC_FS
373	static struct proc_dir_entry *videocodec_proc_entry;
374#endif
375
376	printk(KERN_INFO "Linux video codec intermediate layer: %s\n",
377	       VIDEOCODEC_VERSION);
378
379#ifdef CONFIG_PROC_FS
380	videocodec_proc_entry = proc_create("videocodecs", 0, NULL, &videocodecs_proc_fops);
381	if (!videocodec_proc_entry) {
382		dprintk(1, KERN_ERR "videocodec: can't init procfs.\n");
383	}
384#endif
385	return 0;
386}
387
388static void __exit
389videocodec_exit (void)
390{
391#ifdef CONFIG_PROC_FS
392	remove_proc_entry("videocodecs", NULL);
393#endif
394}
395
396EXPORT_SYMBOL(videocodec_attach);
397EXPORT_SYMBOL(videocodec_detach);
398EXPORT_SYMBOL(videocodec_register);
399EXPORT_SYMBOL(videocodec_unregister);
400
401module_init(videocodec_init);
402module_exit(videocodec_exit);
403
404MODULE_AUTHOR("Wolfgang Scherr <scherr@net4you.at>");
405MODULE_DESCRIPTION("Intermediate API module for video codecs "
406		   VIDEOCODEC_VERSION);
407MODULE_LICENSE("GPL");
408