drivers/video/fbdev/c2p_iplan2.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 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
  27 static 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
  41 static 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
  48 static 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
  61 static 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
  85 void 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 }
 151 EXPORT_SYMBOL_GPL(c2p_iplan2);
 152
 153 MODULE_LICENSE("GPL");