1 /*
2 * Fast C2P (Chunky-to-Planar) Conversion
3 *
4 * Copyright (C) 2003-2008 Geert Uytterhoeven
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file COPYING in the main directory of this archive
8 * for more details.
9 */
10
11 #include <linux/module.h>
12 #include <linux/string.h>
13
14 #include <linux/unaligned.h>
15
16 #include "c2p.h"
17 #include "c2p_core.h"
18
19
20 /*
21 * Perform a full C2P step on 32 8-bit pixels, stored in 8 32-bit words
22 * containing
23 * - 32 8-bit chunky pixels on input
24 * - permutated planar data (1 plane per 32-bit word) on output
25 */
26
c2p_32x8(u32 d[8])27 static void c2p_32x8(u32 d[8])
28 {
29 transp8(d, 16, 4);
30 transp8(d, 8, 2);
31 transp8(d, 4, 1);
32 transp8(d, 2, 4);
33 transp8(d, 1, 2);
34 }
35
36
37 /*
38 * Array containing the permutation indices of the planar data after c2p
39 */
40
41 static const int perm_c2p_32x8[8] = { 7, 5, 3, 1, 6, 4, 2, 0 };
42
43
44 /*
45 * Store a full block of planar data after c2p conversion
46 */
47
store_planar(void * dst,u32 dst_inc,u32 bpp,u32 d[8])48 static inline void store_planar(void *dst, u32 dst_inc, u32 bpp, u32 d[8])
49 {
50 int i;
51
52 for (i = 0; i < bpp; i++, dst += dst_inc)
53 put_unaligned_be32(d[perm_c2p_32x8[i]], dst);
54 }
55
56
57 /*
58 * Store a partial block of planar data after c2p conversion
59 */
60
store_planar_masked(void * dst,u32 dst_inc,u32 bpp,u32 d[8],u32 mask)61 static inline void store_planar_masked(void *dst, u32 dst_inc, u32 bpp,
62 u32 d[8], u32 mask)
63 {
64 int i;
65
66 for (i = 0; i < bpp; i++, dst += dst_inc)
67 put_unaligned_be32(comp(d[perm_c2p_32x8[i]],
68 get_unaligned_be32(dst), mask),
69 dst);
70 }
71
72
73 /*
74 * c2p_planar - Copy 8-bit chunky image data to a planar frame buffer
75 * @dst: Starting address of the planar frame buffer
76 * @dx: Horizontal destination offset (in pixels)
77 * @dy: Vertical destination offset (in pixels)
78 * @width: Image width (in pixels)
79 * @height: Image height (in pixels)
80 * @dst_nextline: Frame buffer offset to the next line (in bytes)
81 * @dst_nextplane: Frame buffer offset to the next plane (in bytes)
82 * @src_nextline: Image offset to the next line (in bytes)
83 * @bpp: Bits per pixel of the planar frame buffer (1-8)
84 */
85
c2p_planar(void * dst,const void * src,u32 dx,u32 dy,u32 width,u32 height,u32 dst_nextline,u32 dst_nextplane,u32 src_nextline,u32 bpp)86 void c2p_planar(void *dst, const void *src, u32 dx, u32 dy, u32 width,
87 u32 height, u32 dst_nextline, u32 dst_nextplane,
88 u32 src_nextline, u32 bpp)
89 {
90 union {
91 u8 pixels[32];
92 u32 words[8];
93 } d;
94 u32 dst_idx, first, last, w;
95 const u8 *c;
96 void *p;
97
98 dst += dy*dst_nextline+(dx & ~31);
99 dst_idx = dx % 32;
100 first = 0xffffffffU >> dst_idx;
101 last = ~(0xffffffffU >> ((dst_idx+width) % 32));
102 while (height--) {
103 c = src;
104 p = dst;
105 w = width;
106 if (dst_idx+width <= 32) {
107 /* Single destination word */
108 first &= last;
109 memset(d.pixels, 0, sizeof(d));
110 memcpy(d.pixels+dst_idx, c, width);
111 c += width;
112 c2p_32x8(d.words);
113 store_planar_masked(p, dst_nextplane, bpp, d.words,
114 first);
115 p += 4;
116 } else {
117 /* Multiple destination words */
118 w = width;
119 /* Leading bits */
120 if (dst_idx) {
121 w = 32 - dst_idx;
122 memset(d.pixels, 0, dst_idx);
123 memcpy(d.pixels+dst_idx, c, w);
124 c += w;
125 c2p_32x8(d.words);
126 store_planar_masked(p, dst_nextplane, bpp,
127 d.words, first);
128 p += 4;
129 w = width-w;
130 }
131 /* Main chunk */
132 while (w >= 32) {
133 memcpy(d.pixels, c, 32);
134 c += 32;
135 c2p_32x8(d.words);
136 store_planar(p, dst_nextplane, bpp, d.words);
137 p += 4;
138 w -= 32;
139 }
140 /* Trailing bits */
141 w %= 32;
142 if (w > 0) {
143 memcpy(d.pixels, c, w);
144 memset(d.pixels+w, 0, 32-w);
145 c2p_32x8(d.words);
146 store_planar_masked(p, dst_nextplane, bpp,
147 d.words, last);
148 }
149 }
150 src += src_nextline;
151 dst += dst_nextline;
152 }
153 }
154 EXPORT_SYMBOL_GPL(c2p_planar);
155
156 MODULE_DESCRIPTION("Fast C2P (Chunky-to-Planar) Conversion");
157 MODULE_LICENSE("GPL");
158