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 <asm/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
 27static 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
 41static 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
 48static 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
 61static 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
 86void 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}
154EXPORT_SYMBOL_GPL(c2p_planar);
155
156MODULE_LICENSE("GPL");