drivers/video/c2p_planar.c

   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
  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
  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
  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
  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_LICENSE("GPL");