pwc-uncompress.c

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/* Linux driver for Philips webcam
   Decompression frontend.
   (C) 1999-2003 Nemosoft Unv.
   (C) 2004-2006 Luc Saillard ([email protected])

   NOTE: this version of pwc is an unofficial (modified) release of pwc & pcwx
   driver and thus may have bugs that are not present in the original version.
   Please send bug reports and support requests to <[email protected]>.
   The decompression routines have been implemented by reverse-engineering the
   Nemosoft binary pwcx module. Caveat emptor.

   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

   vim: set ts=8:
*/

#include <asm/current.h>
#include <asm/types.h>

#include "pwc.h"
#include "pwc-dec1.h"
#include "pwc-dec23.h"

int pwc_decompress(struct pwc_device *pdev, struct pwc_frame_buf *fbuf)
{
    int n, line, col;
    void *yuv, *image;
    u16 *src;
    u16 *dsty, *dstu, *dstv;

    image = vb2_plane_vaddr(&fbuf->vb, 0);

    yuv = fbuf->data + pdev->frame_header_size;  /* Skip header */

    /* Raw format; that's easy... */
    if (pdev->pixfmt != V4L2_PIX_FMT_YUV420)
    {
        struct pwc_raw_frame *raw_frame = image;
        raw_frame->type = cpu_to_le16(pdev->type);
        raw_frame->vbandlength = cpu_to_le16(pdev->vbandlength);
            /* cmd_buf is always 4 bytes, but sometimes, only the
             * first 3 bytes is filled (Nala case). We can
             * determine this using the type of the webcam */
        memcpy(raw_frame->cmd, pdev->cmd_buf, 4);
        memcpy(raw_frame+1, yuv, pdev->frame_size);
        vb2_set_plane_payload(&fbuf->vb, 0,
            pdev->frame_size + sizeof(struct pwc_raw_frame));
        return 0;
    }

    vb2_set_plane_payload(&fbuf->vb, 0,
                  pdev->width * pdev->height * 3 / 2);

    if (pdev->vbandlength == 0) {
        /* Uncompressed mode.
         *
         * We do some byte shuffling here to go from the
         * native format to YUV420P.
         */
        src = (u16 *)yuv;
        n = pdev->width * pdev->height;
        dsty = (u16 *)(image);
        dstu = (u16 *)(image + n);
        dstv = (u16 *)(image + n + n / 4);

        for (line = 0; line < pdev->height; line++) {
            for (col = 0; col < pdev->width; col += 4) {
                *dsty++ = *src++;
                *dsty++ = *src++;
                if (line & 1)
                    *dstv++ = *src++;
                else
                    *dstu++ = *src++;
            }
        }

        return 0;
    }

    /*
     * Compressed;
     * the decompressor routines will write the data in planar format
     * immediately.
     */
    if (DEVICE_USE_CODEC1(pdev->type)) {

        /* TODO & FIXME */
        PWC_ERROR("This chipset is not supported for now\n");
        return -ENXIO; /* No such device or address: missing decompressor */

    } else {
        pwc_dec23_decompress(pdev, yuv, image);
    }
    return 0;
}