File: /usr/src/linux/drivers/usb/pwc-uncompress.c
1 /* Linux driver for Philips webcam
2 Decompression frontend.
3 (C) 1999-2001 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 */
31 static 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 dynamicly adjust our structure.
36 */
37 const int pwc_decompressor_version = PWC_MAJOR;
38
39 /* Add decompressor to list, ignoring duplicates */
40 void 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 */
49 void 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 */
61 struct 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
76 int pwc_decompress(struct pwc_device *pdev)
77 {
78 struct pwc_frame_buf *fbuf;
79 int n, line, col, stride;
80 void *yuv, *image, *dst;
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 #if PWC_DEBUG
102 /* This is a quickie */
103 if (pdev->vpalette == VIDEO_PALETTE_RAW) {
104 memcpy(image, fbuf->data, pdev->frame_size);
105 return 0;
106 }
107 #endif
108
109 yuv = fbuf->data + pdev->frame_header_size; /* Skip header */
110 if (pdev->vbandlength == 0) {
111 /* Uncompressed mode. We copy the data into the output buffer,
112 using the viewport size (which may be larger than the image
113 size). Unfortunately we have to do a bit of byte stuffing
114 to get the desired output format/size.
115 */
116 switch (pdev->vpalette) {
117 case VIDEO_PALETTE_YUV420:
118 /* Calculate byte offsets per line in image & view */
119 n = (pdev->image.x * 3) / 2;
120 col = (pdev->view.x * 3) / 2;
121 /* Offset into image */
122 dst = image + (pdev->view.x * pdev->offset.y + pdev->offset.x) * 3 / 2;
123 for (line = 0; line < pdev->image.y; line++) {
124 memcpy(dst, yuv, n);
125 yuv += n;
126 dst += col;
127 }
128 break;
129
130 case VIDEO_PALETTE_YUV420P:
131 /*
132 * We do some byte shuffling here to go from the
133 * native format to YUV420P.
134 */
135 src = (u16 *)yuv;
136 n = pdev->view.x * pdev->view.y;
137
138 /* offset in Y plane */
139 stride = pdev->view.x * pdev->offset.y + pdev->offset.x;
140 dsty = (u16 *)(image + stride);
141
142 /* offsets in U/V planes */
143 stride = pdev->view.x * pdev->offset.y / 4 + pdev->offset.x / 2;
144 dstu = (u16 *)(image + n + stride);
145 dstv = (u16 *)(image + n + n / 4 + stride);
146
147 /* increment after each line */
148 stride = (pdev->view.x - pdev->image.x) / 2; /* u16 is 2 bytes */
149
150 for (line = 0; line < pdev->image.y; line++) {
151 for (col = 0; col < pdev->image.x; col += 4) {
152 *dsty++ = *src++;
153 *dsty++ = *src++;
154 if (line & 1)
155 *dstv++ = *src++;
156 else
157 *dstu++ = *src++;
158 }
159 dsty += stride;
160 if (line & 1)
161 dstv += (stride >> 1);
162 else
163 dstu += (stride >> 1);
164 }
165 break;
166 }
167 }
168 else {
169 /* Compressed; the decompressor routines will write the data
170 in interlaced or planar format immediately.
171 */
172 if (pdev->decompressor)
173 pdev->decompressor->decompress(
174 &pdev->image, &pdev->view, &pdev->offset,
175 yuv, image,
176 pdev->vpalette == VIDEO_PALETTE_YUV420P ? 1 : 0,
177 pdev->decompress_data, pdev->vbandlength);
178 else
179 return -ENXIO; /* No such device or address: missing decompressor */
180 }
181 return 0;
182 }
183
184 /* Make sure these functions are available for the decompressor plugin
185 both when this code is compiled into the kernel or as as module.
186 */
187
188 EXPORT_SYMBOL_NOVERS(pwc_decompressor_version);
189 EXPORT_SYMBOL(pwc_register_decompressor);
190 EXPORT_SYMBOL(pwc_unregister_decompressor);
191