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/* Linux driver for Philips webcam
Decompression frontend.
(C) 1999-2001 Nemosoft Unv. (webcam@smcc.demon.nl)
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
This is where the decompression routines register and unregister
themselves. It also has a decompressor wrapper function.
*/
#include <asm/types.h>
#include "pwc.h"
#include "pwc-uncompress.h"
/* This contains a list of all registered decompressors */
static LIST_HEAD(pwc_decompressor_list);
/* Should the pwc_decompress structure ever change, we increase the
version number so that we don't get nasty surprises, or can
dynamicly adjust our structure.
*/
const int pwc_decompressor_version = PWC_MAJOR;
/* Add decompressor to list, ignoring duplicates */
void pwc_register_decompressor(struct pwc_decompressor *pwcd)
{
if (pwc_find_decompressor(pwcd->type) == NULL) {
Trace(TRACE_PWCX, "Adding decompressor for model %d.\n", pwcd->type);
list_add_tail(&pwcd->pwcd_list, &pwc_decompressor_list);
}
}
/* Remove decompressor from list */
void pwc_unregister_decompressor(int type)
{
struct pwc_decompressor *find;
find = pwc_find_decompressor(type);
if (find != NULL) {
Trace(TRACE_PWCX, "Removing decompressor for model %d.\n", type);
list_del(&find->pwcd_list);
}
}
/* Find decompressor in list */
struct pwc_decompressor *pwc_find_decompressor(int type)
{
struct list_head *tmp;
struct pwc_decompressor *pwcd;
list_for_each(tmp, &pwc_decompressor_list) {
pwcd = list_entry(tmp, struct pwc_decompressor, pwcd_list);
if (pwcd->type == type)
return pwcd;
}
return NULL;
}
int pwc_decompress(struct pwc_device *pdev)
{
struct pwc_frame_buf *fbuf;
int n, line, col, stride;
void *yuv, *image, *dst;
u16 *src;
u16 *dsty, *dstu, *dstv;
if (pdev == NULL)
return -EFAULT;
#if defined(__KERNEL__) && defined(PWC_MAGIC)
if (pdev->magic != PWC_MAGIC) {
Err("pwc_decompress(): magic failed.\n");
return -EFAULT;
}
#endif
fbuf = pdev->read_frame;
if (fbuf == NULL)
return -EFAULT;
image = pdev->image_ptr[pdev->fill_image];
if (!image)
return -EFAULT;
#if PWC_DEBUG
/* This is a quickie */
if (pdev->vpalette == VIDEO_PALETTE_RAW) {
memcpy(image, fbuf->data, pdev->frame_size);
return 0;
}
#endif
yuv = fbuf->data + pdev->frame_header_size; /* Skip header */
if (pdev->vbandlength == 0) {
/* Uncompressed mode. We copy the data into the output buffer,
using the viewport size (which may be larger than the image
size). Unfortunately we have to do a bit of byte stuffing
to get the desired output format/size.
*/
switch (pdev->vpalette) {
case VIDEO_PALETTE_YUV420:
/* Calculate byte offsets per line in image & view */
n = (pdev->image.x * 3) / 2;
col = (pdev->view.x * 3) / 2;
/* Offset into image */
dst = image + (pdev->view.x * pdev->offset.y + pdev->offset.x) * 3 / 2;
for (line = 0; line < pdev->image.y; line++) {
memcpy(dst, yuv, n);
yuv += n;
dst += col;
}
break;
case VIDEO_PALETTE_YUV420P:
/*
* We do some byte shuffling here to go from the
* native format to YUV420P.
*/
src = (u16 *)yuv;
n = pdev->view.x * pdev->view.y;
/* offset in Y plane */
stride = pdev->view.x * pdev->offset.y + pdev->offset.x;
dsty = (u16 *)(image + stride);
/* offsets in U/V planes */
stride = pdev->view.x * pdev->offset.y / 4 + pdev->offset.x / 2;
dstu = (u16 *)(image + n + stride);
dstv = (u16 *)(image + n + n / 4 + stride);
/* increment after each line */
stride = (pdev->view.x - pdev->image.x) / 2; /* u16 is 2 bytes */
for (line = 0; line < pdev->image.y; line++) {
for (col = 0; col < pdev->image.x; col += 4) {
*dsty++ = *src++;
*dsty++ = *src++;
if (line & 1)
*dstv++ = *src++;
else
*dstu++ = *src++;
}
dsty += stride;
if (line & 1)
dstv += (stride >> 1);
else
dstu += (stride >> 1);
}
break;
}
}
else {
/* Compressed; the decompressor routines will write the data
in interlaced or planar format immediately.
*/
if (pdev->decompressor)
pdev->decompressor->decompress(
&pdev->image, &pdev->view, &pdev->offset,
yuv, image,
pdev->vpalette == VIDEO_PALETTE_YUV420P ? 1 : 0,
pdev->decompress_data, pdev->vbandlength);
else
return -ENXIO; /* No such device or address: missing decompressor */
}
return 0;
}
/* Make sure these functions are available for the decompressor plugin
both when this code is compiled into the kernel or as as module.
*/
EXPORT_SYMBOL_NOVERS(pwc_decompressor_version);
EXPORT_SYMBOL(pwc_register_decompressor);
EXPORT_SYMBOL(pwc_unregister_decompressor);
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