git.mutantstargoat.com Git - gba_blender/blob - src/dma.c

   1 /*
   2 gbasys - a gameboy advance hardware abstraction library
   3 Copyright (C) 2004-2021  John Tsiombikas <nuclear@member.fsf.org>
   4
   5 This program is free software: you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation, either version 3 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18 #include "dma.h"
  19
  20 /* DMA Options */
  21 #define DMA_ENABLE                              0x80000000
  22 #define DMA_INT_ENABLE                  0x40000000
  23 #define DMA_TIMING_IMMED                0x00000000
  24 #define DMA_TIMING_VBLANK               0x10000000
  25 #define DMA_TIMING_HBLANK               0x20000000
  26 #define DMA_TIMING_DISPSYNC             0x30000000
  27 #define DMA_16                                  0x00000000
  28 #define DMA_32                                  0x04000000
  29 #define DMA_REPEAT                              0x02000000
  30 #define DMA_SRC_INC                             0x00000000
  31 #define DMA_SRC_DEC                             0x00800000
  32 #define DMA_SRC_FIX                             0x01000000
  33 #define DMA_DST_INC                             0x00000000
  34 #define DMA_DST_DEC                             0x00200000
  35 #define DMA_DST_FIX1                    0x00400000
  36 #define DMA_DST_RELOAD                  0x00600000
  37
  38 /* DMA Register Parts */
  39 #define DMA_SRC         0
  40 #define DMA_DST         1
  41 #define DMA_CTRL        2
  42
  43 static volatile unsigned long *reg_dma[4] = {(void*)0x040000b0, (void*)0x040000bc, (void*)0x040000c8, (void*)0x040000d4 };
  44
  45 /* --- perform a copy of words or halfwords using DMA --- */
  46
  47 void dma_copy32(int channel, void *dst, void *src, int words, unsigned int flags)
  48 {
  49         reg_dma[channel][DMA_SRC] = (unsigned long)src;
  50         reg_dma[channel][DMA_DST] = (unsigned long)dst;
  51         reg_dma[channel][DMA_CTRL] = words | flags | DMA_32 | DMA_ENABLE;
  52 }
  53
  54 void dma_copy16(int channel, void *dst, void *src, int halfwords, unsigned int flags)
  55 {
  56         reg_dma[channel][DMA_SRC] = (unsigned long)src;
  57         reg_dma[channel][DMA_DST] = (unsigned long)dst;
  58         reg_dma[channel][DMA_CTRL] = halfwords | flags | DMA_16 | DMA_ENABLE;
  59 }
  60
  61 /* --- fill a buffer with an ammount of words and halfwords using DMA --- */
  62
  63 static unsigned long fill[4];
  64
  65 void dma_fill32(int channel, void *dst, unsigned long val, int words)
  66 {
  67         fill[channel] = val;
  68         reg_dma[channel][DMA_SRC] = (unsigned long)(fill + channel);
  69         reg_dma[channel][DMA_DST] = (unsigned long)dst;
  70         reg_dma[channel][DMA_CTRL] = words | DMA_SRC_FIX | DMA_TIMING_IMMED | DMA_32 | DMA_ENABLE;
  71 }
  72
  73 void dma_fill16(int channel, void *dst, unsigned short val, int halfwords)
  74 {
  75         fill[channel] = val;
  76         reg_dma[channel][DMA_SRC] = (unsigned long)(fill + channel);
  77         reg_dma[channel][DMA_DST] = (unsigned long)dst;
  78         reg_dma[channel][DMA_CTRL] = halfwords | DMA_SRC_FIX | DMA_TIMING_IMMED | DMA_16 | DMA_ENABLE;
  79 }