LXR linux/drivers/video/fbdev/c2p

   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 16 8-bit pixels, stored in 4 32-bit words
  22     *  containing
  23     *    - 16 8-bit chunky pixels on input
  24     *    - permutated planar data (2 planes per 32-bit word) on output
  25     */
  26
  27static void c2p_16x8(u32 d[4])
  28{
  29        transp4(d, 8, 2);
  30        transp4(d, 1, 2);
  31        transp4x(d, 16, 2);
  32        transp4x(d, 2, 2);
  33        transp4(d, 4, 1);
  34}
  35
  36
  37    /*
  38     *  Array containing the permutation indices of the planar data after c2p
  39     */
  40
  41static const int perm_c2p_16x8[4] = { 1, 3, 0, 2 };
  42
  43
  44    /*
  45     *  Store a full block of iplan2 data after c2p conversion
  46     */
  47
  48static inline void store_iplan2(void *dst, u32 bpp, u32 d[4])
  49{
  50        int i;
  51
  52        for (i = 0; i < bpp/2; i++, dst += 4)
  53                put_unaligned_be32(d[perm_c2p_16x8[i]], dst);
  54}
  55
  56
  57    /*
  58     *  Store a partial block of iplan2 data after c2p conversion
  59     */
  60
  61static inline void store_iplan2_masked(void *dst, u32 bpp, u32 d[4], u32 mask)
  62{
  63        int i;
  64
  65        for (i = 0; i < bpp/2; i++, dst += 4)
  66                put_unaligned_be32(comp(d[perm_c2p_16x8[i]],
  67                                        get_unaligned_be32(dst), mask),
  68                                   dst);
  69}
  70
  71
  72    /*
  73     *  c2p_iplan2 - Copy 8-bit chunky image data to an interleaved planar
  74     *  frame buffer with 2 bytes of interleave
  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     *  @src_nextline: Image offset to the next line (in bytes)
  82     *  @bpp: Bits per pixel of the planar frame buffer (2, 4, or 8)
  83     */
  84
  85void c2p_iplan2(void *dst, const void *src, u32 dx, u32 dy, u32 width,
  86                u32 height, u32 dst_nextline, u32 src_nextline, u32 bpp)
  87{
  88        union {
  89                u8 pixels[16];
  90                u32 words[4];
  91        } d;
  92        u32 dst_idx, first, last, w;
  93        const u8 *c;
  94        void *p;
  95
  96        dst += dy*dst_nextline+(dx & ~15)*bpp;
  97        dst_idx = dx % 16;
  98        first = 0xffffU >> dst_idx;
  99        first |= first << 16;
 100        last = 0xffffU ^ (0xffffU >> ((dst_idx+width) % 16));
 101        last |= last << 16;
 102        while (height--) {
 103                c = src;
 104                p = dst;
 105                w = width;
 106                if (dst_idx+width <= 16) {
 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_16x8(d.words);
 113                        store_iplan2_masked(p, bpp, d.words, first);
 114                        p += bpp*2;
 115                } else {
 116                        /* Multiple destination words */
 117                        w = width;
 118                        /* Leading bits */
 119                        if (dst_idx) {
 120                                w = 16 - dst_idx;
 121                                memset(d.pixels, 0, dst_idx);
 122                                memcpy(d.pixels+dst_idx, c, w);
 123                                c += w;
 124                                c2p_16x8(d.words);
 125                                store_iplan2_masked(p, bpp, d.words, first);
 126                                p += bpp*2;
 127                                w = width-w;
 128                        }
 129                        /* Main chunk */
 130                        while (w >= 16) {
 131                                memcpy(d.pixels, c, 16);
 132                                c += 16;
 133                                c2p_16x8(d.words);
 134                                store_iplan2(p, bpp, d.words);
 135                                p += bpp*2;
 136                                w -= 16;
 137                        }
 138                        /* Trailing bits */
 139                        w %= 16;
 140                        if (w > 0) {
 141                                memcpy(d.pixels, c, w);
 142                                memset(d.pixels+w, 0, 16-w);
 143                                c2p_16x8(d.words);
 144                                store_iplan2_masked(p, bpp, d.words, last);
 145                        }
 146                }
 147                src += src_nextline;
 148                dst += dst_nextline;
 149        }
 150}
 151EXPORT_SYMBOL_GPL(c2p_iplan2);
 152
 153MODULE_LICENSE("GPL");
 154