1/* Linux driver for Philips webcam
2   Decompression frontend.
3   (C) 1999-2003 Nemosoft Unv. (webcam@smcc.demon.nl)
4
5   This program is free software; you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 2 of the License, or
8   (at your option) any later version.
9
10   This program is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   GNU General Public License for more details.
14
15   You should have received a copy of the GNU General Public License
16   along with this program; if not, write to the Free Software
17   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18*/
19/*
20   This is where the decompression routines register and unregister
21   themselves. It also has a decompressor wrapper function.
22*/
23
24#include <asm/types.h>
25
26#include "pwc.h"
27#include "pwc-uncompress.h"
28
29
30/* This contains a list of all registered decompressors */
31static LIST_HEAD(pwc_decompressor_list);
32
33/* Should the pwc_decompress structure ever change, we increase the
34   version number so that we don't get nasty surprises, or can
35   dynamically adjust our structure.
36 */
37const int pwc_decompressor_version = PWC_MAJOR;
38
39/* Add decompressor to list, ignoring duplicates */
40void pwc_register_decompressor(struct pwc_decompressor *pwcd)
41{
42	if (pwc_find_decompressor(pwcd->type) == NULL) {
43		Trace(TRACE_PWCX, "Adding decompressor for model %d.\n", pwcd->type);
44		list_add_tail(&pwcd->pwcd_list, &pwc_decompressor_list);
45	}
46}
47
48/* Remove decompressor from list */
49void pwc_unregister_decompressor(int type)
50{
51	struct pwc_decompressor *find;
52
53	find = pwc_find_decompressor(type);
54	if (find != NULL) {
55		Trace(TRACE_PWCX, "Removing decompressor for model %d.\n", type);
56		list_del(&find->pwcd_list);
57	}
58}
59
60/* Find decompressor in list */
61struct pwc_decompressor *pwc_find_decompressor(int type)
62{
63	struct list_head *tmp;
64	struct pwc_decompressor *pwcd;
65
66	list_for_each(tmp, &pwc_decompressor_list) {
67		pwcd  = list_entry(tmp, struct pwc_decompressor, pwcd_list);
68		if (pwcd->type == type)
69			return pwcd;
70	}
71	return NULL;
72}
73
74
75
76int pwc_decompress(struct pwc_device *pdev)
77{
78	struct pwc_frame_buf *fbuf;
79	int n, line, col, stride;
80	void *yuv, *image;
81	u16 *src;
82	u16 *dsty, *dstu, *dstv;
83
84
85	if (pdev == NULL)
86		return -EFAULT;
87#if defined(__KERNEL__) && defined(PWC_MAGIC)
88	if (pdev->magic != PWC_MAGIC) {
89		Err("pwc_decompress(): magic failed.\n");
90		return -EFAULT;
91	}
92#endif
93
94	fbuf = pdev->read_frame;
95	if (fbuf == NULL)
96		return -EFAULT;
97	image = pdev->image_ptr[pdev->fill_image];
98	if (!image)
99		return -EFAULT;
100
101	yuv = fbuf->data + pdev->frame_header_size;  /* Skip header */
102	if (pdev->vbandlength == 0) {
103		/* Uncompressed mode. We copy the data into the output buffer,
104		   using the viewport size (which may be larger than the image
105		   size). Unfortunately we have to do a bit of byte stuffing
106		   to get the desired output format/size.
107		 */
108			/*
109			 * We do some byte shuffling here to go from the
110			 * native format to YUV420P.
111			 */
112			src = (u16 *)yuv;
113			n = pdev->view.x * pdev->view.y;
114
115			/* offset in Y plane */
116			stride = pdev->view.x * pdev->offset.y + pdev->offset.x;
117			dsty = (u16 *)(image + stride);
118
119			/* offsets in U/V planes */
120			stride = pdev->view.x * pdev->offset.y / 4 + pdev->offset.x / 2;
121			dstu = (u16 *)(image + n +         stride);
122			dstv = (u16 *)(image + n + n / 4 + stride);
123
124			/* increment after each line */
125			stride = (pdev->view.x - pdev->image.x) / 2; /* u16 is 2 bytes */
126
127			for (line = 0; line < pdev->image.y; line++) {
128				for (col = 0; col < pdev->image.x; col += 4) {
129					*dsty++ = *src++;
130					*dsty++ = *src++;
131					if (line & 1)
132						*dstv++ = *src++;
133					else
134						*dstu++ = *src++;
135				}
136				dsty += stride;
137				if (line & 1)
138					dstv += (stride >> 1);
139				else
140					dstu += (stride >> 1);
141			}
142	}
143	else {
144		/* Compressed; the decompressor routines will write the data
145		   in planar format immediately.
146		 */
147		if (pdev->decompressor)
148			pdev->decompressor->decompress(
149				&pdev->image, &pdev->view, &pdev->offset,
150				yuv, image,
151				1,
152				pdev->decompress_data, pdev->vbandlength);
153		else
154			return -ENXIO; /* No such device or address: missing decompressor */
155	}
156	return 0;
157}
158
159/* Make sure these functions are available for the decompressor plugin
160   both when this code is compiled into the kernel or as as module.
161 */
162
163EXPORT_SYMBOL_NOVERS(pwc_decompressor_version);
164EXPORT_SYMBOL(pwc_register_decompressor);
165EXPORT_SYMBOL(pwc_unregister_decompressor);
166