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846 giacomo 1
/* Linux driver for Philips webcam
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   Decompression frontend.
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   (C) 1999-2003 Nemosoft Unv. (webcam@smcc.demon.nl)
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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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   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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   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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*/
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/*
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   This is where the decompression routines register and unregister
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   themselves. It also has a decompressor wrapper function.
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*/
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#include <asm/current.h>
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#include <asm/types.h>
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// #include <linux/sched.h>
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#include "pwc.h"
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#include "pwc-uncompress.h"
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/* This contains a list of all registered decompressors */
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static LIST_HEAD(pwc_decompressor_list);
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/* Should the pwc_decompress structure ever change, we increase the
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   version number so that we don't get nasty surprises, or can
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   dynamically adjust our structure.
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 */
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const int pwc_decompressor_version = PWC_MAJOR;
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/* Add decompressor to list, ignoring duplicates */
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void pwc_register_decompressor(struct pwc_decompressor *pwcd)
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{
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        if (pwc_find_decompressor(pwcd->type) == NULL) {
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                Trace(TRACE_PWCX, "Adding decompressor for model %d.\n", pwcd->type);
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                list_add_tail(&pwcd->pwcd_list, &pwc_decompressor_list);
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        }
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}
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/* Remove decompressor from list */
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void pwc_unregister_decompressor(int type)
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{
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        struct pwc_decompressor *find;
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        find = pwc_find_decompressor(type);
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        if (find != NULL) {
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                Trace(TRACE_PWCX, "Removing decompressor for model %d.\n", type);
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                list_del(&find->pwcd_list);
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        }
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}
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/* Find decompressor in list */
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struct pwc_decompressor *pwc_find_decompressor(int type)
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{
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        struct list_head *tmp;
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        struct pwc_decompressor *pwcd;
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        list_for_each(tmp, &pwc_decompressor_list) {
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                pwcd  = list_entry(tmp, struct pwc_decompressor, pwcd_list);
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                if (pwcd->type == type)
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                        return pwcd;
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        }
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        return NULL;
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}
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int pwc_decompress(struct pwc_device *pdev)
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{
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        struct pwc_frame_buf *fbuf;
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        int n, line, col, stride;
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        void *yuv, *image;
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        u16 *src;
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        u16 *dsty, *dstu, *dstv;
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        if (pdev == NULL)
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                return -EFAULT;
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#if defined(__KERNEL__) && defined(PWC_MAGIC)
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        if (pdev->magic != PWC_MAGIC) {
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                Err("pwc_decompress(): magic failed.\n");
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                return -EFAULT;
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        }
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#endif
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        fbuf = pdev->read_frame;
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        if (fbuf == NULL)
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                return -EFAULT;
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        image = pdev->image_ptr[pdev->fill_image];
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        if (!image)
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                return -EFAULT;
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        yuv = fbuf->data + pdev->frame_header_size;  /* Skip header */
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        /* Raw format; that's easy... */
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        if (pdev->vpalette == VIDEO_PALETTE_RAW)
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        {
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                memcpy(image, yuv, pdev->frame_size);
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                return 0;
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        }
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        if (pdev->vbandlength == 0) {
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                /* Uncompressed mode. We copy the data into the output buffer,
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                   using the viewport size (which may be larger than the image
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                   size). Unfortunately we have to do a bit of byte stuffing
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                   to get the desired output format/size.
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                 */
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                        /*
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                         * We do some byte shuffling here to go from the
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                         * native format to YUV420P.
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                         */
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                        src = (u16 *)yuv;
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                        n = pdev->view.x * pdev->view.y;
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                        /* offset in Y plane */
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                        stride = pdev->view.x * pdev->offset.y + pdev->offset.x;
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                        dsty = (u16 *)(image + stride);
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                        /* offsets in U/V planes */
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                        stride = pdev->view.x * pdev->offset.y / 4 + pdev->offset.x / 2;
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                        dstu = (u16 *)(image + n +         stride);
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                        dstv = (u16 *)(image + n + n / 4 + stride);
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                        /* increment after each line */
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                        stride = (pdev->view.x - pdev->image.x) / 2; /* u16 is 2 bytes */
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                        for (line = 0; line < pdev->image.y; line++) {
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                                for (col = 0; col < pdev->image.x; col += 4) {
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                                        *dsty++ = *src++;
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                                        *dsty++ = *src++;
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                                        if (line & 1)
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                                                *dstv++ = *src++;
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                                        else
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                                                *dstu++ = *src++;
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                                }
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                                dsty += stride;
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                                if (line & 1)
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                                        dstv += (stride >> 1);
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                                else
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                                        dstu += (stride >> 1);
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                        }
151
        }
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        else {
153
                /* Compressed; the decompressor routines will write the data
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                   in planar format immediately.
155
                 */
156
                int flags;
157
 
158
                flags = PWCX_FLAG_PLANAR;
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                if (pdev->vsize == PSZ_VGA && pdev->vframes == 5 && pdev->vsnapshot)
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                        flags |= PWCX_FLAG_BAYER;
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                if (pdev->decompressor)
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                        pdev->decompressor->decompress(
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                                &pdev->image, &pdev->view, &pdev->offset,
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                                yuv, image,
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                                flags,
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                                pdev->decompress_data, pdev->vbandlength);
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                else
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                        return -ENXIO; /* No such device or address: missing decompressor */
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        }
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        return 0;
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}
173
 
174
/* Make sure these functions are available for the decompressor plugin
175
   both when this code is compiled into the kernel or as as module.
176
 */
177
 
178
EXPORT_SYMBOL_NOVERS(pwc_decompressor_version);
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EXPORT_SYMBOL(pwc_register_decompressor);
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EXPORT_SYMBOL(pwc_unregister_decompressor);