linux/drivers/video/c2p_planar.c
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   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");
 157
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