484 строки
11 KiB
C
484 строки
11 KiB
C
/*
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* VIDEO MOTION CODECs internal API for video devices
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*
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* Interface for MJPEG (and maybe later MPEG/WAVELETS) codec's
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* bound to a master device.
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*
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* (c) 2002 Wolfgang Scherr <scherr@net4you.at>
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*
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* $Id: videocodec.c,v 1.1.2.8 2003/03/29 07:16:04 rbultje Exp $
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*
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* ------------------------------------------------------------------------
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* ------------------------------------------------------------------------
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*/
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#define VIDEOCODEC_VERSION "v0.2"
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/slab.h>
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// kernel config is here (procfs flag)
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#ifdef CONFIG_PROC_FS
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#include <linux/proc_fs.h>
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#include <asm/uaccess.h>
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#endif
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#include "videocodec.h"
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static int debug = 0;
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module_param(debug, int, 0);
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MODULE_PARM_DESC(debug, "Debug level (0-4)");
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#define dprintk(num, format, args...) \
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do { \
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if (debug >= num) \
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printk(format, ##args); \
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} while (0)
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struct attached_list {
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struct videocodec *codec;
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struct attached_list *next;
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};
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struct codec_list {
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const struct videocodec *codec;
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int attached;
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struct attached_list *list;
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struct codec_list *next;
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};
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static struct codec_list *codeclist_top = NULL;
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/* ================================================= */
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/* function prototypes of the master/slave interface */
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/* ================================================= */
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struct videocodec *
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videocodec_attach (struct videocodec_master *master)
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{
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struct codec_list *h = codeclist_top;
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struct attached_list *a, *ptr;
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struct videocodec *codec;
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int res;
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if (!master) {
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dprintk(1, KERN_ERR "videocodec_attach: no data\n");
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return NULL;
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}
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dprintk(2,
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"videocodec_attach: '%s', type: %x, flags %lx, magic %lx\n",
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master->name, master->type, master->flags, master->magic);
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if (!h) {
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dprintk(1,
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KERN_ERR
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"videocodec_attach: no device available\n");
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return NULL;
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}
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while (h) {
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// attach only if the slave has at least the flags
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// expected by the master
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if ((master->flags & h->codec->flags) == master->flags) {
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dprintk(4, "videocodec_attach: try '%s'\n",
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h->codec->name);
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if (!try_module_get(h->codec->owner))
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return NULL;
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codec =
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kmalloc(sizeof(struct videocodec), GFP_KERNEL);
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if (!codec) {
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dprintk(1,
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KERN_ERR
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"videocodec_attach: no mem\n");
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goto out_module_put;
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}
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memcpy(codec, h->codec, sizeof(struct videocodec));
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snprintf(codec->name, sizeof(codec->name),
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"%s[%d]", codec->name, h->attached);
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codec->master_data = master;
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res = codec->setup(codec);
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if (res == 0) {
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dprintk(3, "videocodec_attach '%s'\n",
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codec->name);
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ptr = kzalloc(sizeof(struct attached_list), GFP_KERNEL);
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if (!ptr) {
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dprintk(1,
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KERN_ERR
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"videocodec_attach: no memory\n");
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goto out_kfree;
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}
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ptr->codec = codec;
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a = h->list;
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if (!a) {
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h->list = ptr;
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dprintk(4,
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"videocodec: first element\n");
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} else {
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while (a->next)
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a = a->next; // find end
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a->next = ptr;
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dprintk(4,
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"videocodec: in after '%s'\n",
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h->codec->name);
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}
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h->attached += 1;
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return codec;
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} else {
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kfree(codec);
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}
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}
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h = h->next;
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}
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dprintk(1, KERN_ERR "videocodec_attach: no codec found!\n");
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return NULL;
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out_module_put:
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module_put(h->codec->owner);
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out_kfree:
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kfree(codec);
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return NULL;
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}
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int
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videocodec_detach (struct videocodec *codec)
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{
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struct codec_list *h = codeclist_top;
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struct attached_list *a, *prev;
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int res;
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if (!codec) {
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dprintk(1, KERN_ERR "videocodec_detach: no data\n");
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return -EINVAL;
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}
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dprintk(2,
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"videocodec_detach: '%s', type: %x, flags %lx, magic %lx\n",
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codec->name, codec->type, codec->flags, codec->magic);
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if (!h) {
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dprintk(1,
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KERN_ERR "videocodec_detach: no device left...\n");
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return -ENXIO;
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}
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while (h) {
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a = h->list;
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prev = NULL;
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while (a) {
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if (codec == a->codec) {
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res = a->codec->unset(a->codec);
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if (res >= 0) {
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dprintk(3,
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"videocodec_detach: '%s'\n",
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a->codec->name);
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a->codec->master_data = NULL;
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} else {
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dprintk(1,
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KERN_ERR
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"videocodec_detach: '%s'\n",
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a->codec->name);
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a->codec->master_data = NULL;
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}
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if (prev == NULL) {
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h->list = a->next;
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dprintk(4,
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"videocodec: delete first\n");
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} else {
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prev->next = a->next;
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dprintk(4,
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"videocodec: delete middle\n");
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}
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module_put(a->codec->owner);
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kfree(a->codec);
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kfree(a);
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h->attached -= 1;
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return 0;
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}
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prev = a;
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a = a->next;
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}
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h = h->next;
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}
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dprintk(1, KERN_ERR "videocodec_detach: given codec not found!\n");
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return -EINVAL;
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}
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int
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videocodec_register (const struct videocodec *codec)
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{
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struct codec_list *ptr, *h = codeclist_top;
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if (!codec) {
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dprintk(1, KERN_ERR "videocodec_register: no data!\n");
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return -EINVAL;
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}
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dprintk(2,
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"videocodec: register '%s', type: %x, flags %lx, magic %lx\n",
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codec->name, codec->type, codec->flags, codec->magic);
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ptr = kzalloc(sizeof(struct codec_list), GFP_KERNEL);
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if (!ptr) {
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dprintk(1, KERN_ERR "videocodec_register: no memory\n");
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return -ENOMEM;
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}
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ptr->codec = codec;
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if (!h) {
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codeclist_top = ptr;
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dprintk(4, "videocodec: hooked in as first element\n");
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} else {
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while (h->next)
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h = h->next; // find the end
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h->next = ptr;
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dprintk(4, "videocodec: hooked in after '%s'\n",
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h->codec->name);
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}
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return 0;
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}
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int
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videocodec_unregister (const struct videocodec *codec)
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{
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struct codec_list *prev = NULL, *h = codeclist_top;
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if (!codec) {
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dprintk(1, KERN_ERR "videocodec_unregister: no data!\n");
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return -EINVAL;
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}
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dprintk(2,
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"videocodec: unregister '%s', type: %x, flags %lx, magic %lx\n",
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codec->name, codec->type, codec->flags, codec->magic);
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if (!h) {
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dprintk(1,
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KERN_ERR
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"videocodec_unregister: no device left...\n");
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return -ENXIO;
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}
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while (h) {
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if (codec == h->codec) {
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if (h->attached) {
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dprintk(1,
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KERN_ERR
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"videocodec: '%s' is used\n",
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h->codec->name);
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return -EBUSY;
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}
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dprintk(3, "videocodec: unregister '%s' is ok.\n",
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h->codec->name);
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if (prev == NULL) {
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codeclist_top = h->next;
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dprintk(4,
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"videocodec: delete first element\n");
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} else {
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prev->next = h->next;
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dprintk(4,
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"videocodec: delete middle element\n");
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}
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kfree(h);
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return 0;
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}
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prev = h;
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h = h->next;
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}
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dprintk(1,
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KERN_ERR
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"videocodec_unregister: given codec not found!\n");
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return -EINVAL;
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}
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#ifdef CONFIG_PROC_FS
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/* ============ */
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/* procfs stuff */
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/* ============ */
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static char *videocodec_buf = NULL;
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static int videocodec_bufsize = 0;
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static int
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videocodec_build_table (void)
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{
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struct codec_list *h = codeclist_top;
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struct attached_list *a;
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int i = 0, size;
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// sum up amount of slaves plus their attached masters
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while (h) {
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i += h->attached + 1;
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h = h->next;
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}
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#define LINESIZE 100
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size = LINESIZE * (i + 1);
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dprintk(3, "videocodec_build table: %d entries, %d bytes\n", i,
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size);
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kfree(videocodec_buf);
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videocodec_buf = kmalloc(size, GFP_KERNEL);
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if (!videocodec_buf)
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return 0;
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i = 0;
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i += scnprintf(videocodec_buf + i, size - 1,
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"<S>lave or attached <M>aster name type flags magic ");
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i += scnprintf(videocodec_buf + i, size -i - 1, "(connected as)\n");
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h = codeclist_top;
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while (h) {
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if (i > (size - LINESIZE))
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break; // security check
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i += scnprintf(videocodec_buf + i, size -i -1,
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"S %32s %04x %08lx %08lx (TEMPLATE)\n",
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h->codec->name, h->codec->type,
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h->codec->flags, h->codec->magic);
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a = h->list;
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while (a) {
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if (i > (size - LINESIZE))
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break; // security check
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i += scnprintf(videocodec_buf + i, size -i -1,
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"M %32s %04x %08lx %08lx (%s)\n",
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a->codec->master_data->name,
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a->codec->master_data->type,
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a->codec->master_data->flags,
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a->codec->master_data->magic,
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a->codec->name);
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a = a->next;
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}
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h = h->next;
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}
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return i;
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}
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//The definition:
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//typedef int (read_proc_t)(char *page, char **start, off_t off,
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// int count, int *eof, void *data);
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static int
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videocodec_info (char *buffer,
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char **buffer_location,
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off_t offset,
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int buffer_length,
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int *eof,
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void *data)
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{
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int size;
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dprintk(3, "videocodec_info: offset: %ld, len %d / size %d\n",
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offset, buffer_length, videocodec_bufsize);
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if (offset == 0) {
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videocodec_bufsize = videocodec_build_table();
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}
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if ((offset < 0) || (offset >= videocodec_bufsize)) {
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dprintk(4,
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"videocodec_info: call delivers no result, return 0\n");
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*eof = 1;
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return 0;
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}
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if (buffer_length < (videocodec_bufsize - offset)) {
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dprintk(4, "videocodec_info: %ld needed, %d got\n",
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videocodec_bufsize - offset, buffer_length);
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size = buffer_length;
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} else {
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dprintk(4, "videocodec_info: last reading of %ld bytes\n",
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videocodec_bufsize - offset);
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size = videocodec_bufsize - offset;
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*eof = 1;
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}
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memcpy(buffer, videocodec_buf + offset, size);
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/* doesn't work... */
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/* copy_to_user(buffer, videocodec_buf+offset, size); */
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/* *buffer_location = videocodec_buf+offset; */
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return size;
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}
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#endif
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/* ===================== */
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/* hook in driver module */
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/* ===================== */
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static int __init
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videocodec_init (void)
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{
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#ifdef CONFIG_PROC_FS
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static struct proc_dir_entry *videocodec_proc_entry;
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#endif
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printk(KERN_INFO "Linux video codec intermediate layer: %s\n",
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VIDEOCODEC_VERSION);
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#ifdef CONFIG_PROC_FS
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videocodec_buf = NULL;
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videocodec_bufsize = 0;
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videocodec_proc_entry = create_proc_entry("videocodecs", 0, NULL);
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if (videocodec_proc_entry) {
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videocodec_proc_entry->read_proc = videocodec_info;
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videocodec_proc_entry->write_proc = NULL;
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videocodec_proc_entry->data = NULL;
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videocodec_proc_entry->owner = THIS_MODULE;
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} else {
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dprintk(1, KERN_ERR "videocodec: can't init procfs.\n");
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}
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#endif
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return 0;
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}
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static void __exit
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videocodec_exit (void)
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{
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#ifdef CONFIG_PROC_FS
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remove_proc_entry("videocodecs", NULL);
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kfree(videocodec_buf);
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#endif
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}
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EXPORT_SYMBOL(videocodec_attach);
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EXPORT_SYMBOL(videocodec_detach);
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EXPORT_SYMBOL(videocodec_register);
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EXPORT_SYMBOL(videocodec_unregister);
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module_init(videocodec_init);
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module_exit(videocodec_exit);
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MODULE_AUTHOR("Wolfgang Scherr <scherr@net4you.at>");
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MODULE_DESCRIPTION("Intermediate API module for video codecs "
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VIDEOCODEC_VERSION);
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MODULE_LICENSE("GPL");
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