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linux/drivers/media/video/videocodec.c

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