arch/arm/kernel/dma-isa.c

   1 /*
   2  *  linux/arch/arm/kernel/dma-isa.c
   3  *
   4  *  Copyright (C) 1999-2000 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  *  ISA DMA primitives
  11  *  Taken from various sources, including:
  12  *   linux/include/asm/dma.h: Defines for using and allocating dma channels.
  13  *     Written by Hennus Bergman, 1992.
  14  *     High DMA channel support & info by Hannu Savolainen and John Boyd,
  15  *     Nov. 1992.
  16  *   arch/arm/kernel/dma-ebsa285.c
  17  *   Copyright (C) 1998 Phil Blundell
  18  */
  19 #include <linux/ioport.h>
  20 #include <linux/init.h>
  21 #include <linux/dma-mapping.h>
  22 #include <linux/io.h>
  23
  24 #include <asm/dma.h>
  25 #include <asm/mach/dma.h>
  26
  27 #define ISA_DMA_MODE_READ       0x44
  28 #define ISA_DMA_MODE_WRITE      0x48
  29 #define ISA_DMA_MODE_CASCADE    0xc0
  30 #define ISA_DMA_AUTOINIT        0x10
  31
  32 #define ISA_DMA_MASK            0
  33 #define ISA_DMA_MODE            1
  34 #define ISA_DMA_CLRFF           2
  35 #define ISA_DMA_PGHI            3
  36 #define ISA_DMA_PGLO            4
  37 #define ISA_DMA_ADDR            5
  38 #define ISA_DMA_COUNT           6
  39
  40 static unsigned int isa_dma_port[8][7] = {
  41         /* MASK   MODE   CLRFF  PAGE_HI PAGE_LO ADDR COUNT */
  42         {  0x0a,  0x0b,  0x0c,  0x487,  0x087,  0x00, 0x01 },
  43         {  0x0a,  0x0b,  0x0c,  0x483,  0x083,  0x02, 0x03 },
  44         {  0x0a,  0x0b,  0x0c,  0x481,  0x081,  0x04, 0x05 },
  45         {  0x0a,  0x0b,  0x0c,  0x482,  0x082,  0x06, 0x07 },
  46         {  0xd4,  0xd6,  0xd8,  0x000,  0x000,  0xc0, 0xc2 },
  47         {  0xd4,  0xd6,  0xd8,  0x48b,  0x08b,  0xc4, 0xc6 },
  48         {  0xd4,  0xd6,  0xd8,  0x489,  0x089,  0xc8, 0xca },
  49         {  0xd4,  0xd6,  0xd8,  0x48a,  0x08a,  0xcc, 0xce }
  50 };
  51
  52 static int isa_get_dma_residue(dmach_t channel, dma_t *dma)
  53 {
  54         unsigned int io_port = isa_dma_port[channel][ISA_DMA_COUNT];
  55         int count;
  56
  57         count = 1 + inb(io_port);
  58         count |= inb(io_port) << 8;
  59
  60         return channel < 4 ? count : (count << 1);
  61 }
  62
  63 static void isa_enable_dma(dmach_t channel, dma_t *dma)
  64 {
  65         if (dma->invalid) {
  66                 unsigned long address, length;
  67                 unsigned int mode;
  68                 enum dma_data_direction direction;
  69
  70                 mode = channel & 3;
  71                 switch (dma->dma_mode & DMA_MODE_MASK) {
  72                 case DMA_MODE_READ:
  73                         mode |= ISA_DMA_MODE_READ;
  74                         direction = DMA_FROM_DEVICE;
  75                         break;
  76
  77                 case DMA_MODE_WRITE:
  78                         mode |= ISA_DMA_MODE_WRITE;
  79                         direction = DMA_TO_DEVICE;
  80                         break;
  81
  82                 case DMA_MODE_CASCADE:
  83                         mode |= ISA_DMA_MODE_CASCADE;
  84                         direction = DMA_BIDIRECTIONAL;
  85                         break;
  86
  87                 default:
  88                         direction = DMA_NONE;
  89                         break;
  90                 }
  91
  92                 if (!dma->sg) {
  93                         /*
  94                          * Cope with ISA-style drivers which expect cache
  95                          * coherence.
  96                          */
  97                         dma->sg = &dma->buf;
  98                         dma->sgcount = 1;
  99                         dma->buf.length = dma->count;
 100                         dma->buf.dma_address = dma_map_single(NULL,
 101                                 dma->addr, dma->count,
 102                                 direction);
 103                 }
 104
 105                 address = dma->buf.dma_address;
 106                 length  = dma->buf.length - 1;
 107
 108                 outb(address >> 16, isa_dma_port[channel][ISA_DMA_PGLO]);
 109                 outb(address >> 24, isa_dma_port[channel][ISA_DMA_PGHI]);
 110
 111                 if (channel >= 4) {
 112                         address >>= 1;
 113                         length >>= 1;
 114                 }
 115
 116                 outb(0, isa_dma_port[channel][ISA_DMA_CLRFF]);
 117
 118                 outb(address, isa_dma_port[channel][ISA_DMA_ADDR]);
 119                 outb(address >> 8, isa_dma_port[channel][ISA_DMA_ADDR]);
 120
 121                 outb(length, isa_dma_port[channel][ISA_DMA_COUNT]);
 122                 outb(length >> 8, isa_dma_port[channel][ISA_DMA_COUNT]);
 123
 124                 if (dma->dma_mode & DMA_AUTOINIT)
 125                         mode |= ISA_DMA_AUTOINIT;
 126
 127                 outb(mode, isa_dma_port[channel][ISA_DMA_MODE]);
 128                 dma->invalid = 0;
 129         }
 130         outb(channel & 3, isa_dma_port[channel][ISA_DMA_MASK]);
 131 }
 132
 133 static void isa_disable_dma(dmach_t channel, dma_t *dma)
 134 {
 135         outb(channel | 4, isa_dma_port[channel][ISA_DMA_MASK]);
 136 }
 137
 138 static struct dma_ops isa_dma_ops = {
 139         .type           = "ISA",
 140         .enable         = isa_enable_dma,
 141         .disable        = isa_disable_dma,
 142         .residue        = isa_get_dma_residue,
 143 };
 144
 145 static struct resource dma_resources[] = { {
 146         .name   = "dma1",
 147         .start  = 0x0000,
 148         .end    = 0x000f
 149 }, {
 150         .name   = "dma low page",
 151         .start  = 0x0080,
 152         .end    = 0x008f
 153 }, {
 154         .name   = "dma2",
 155         .start  = 0x00c0,
 156         .end    = 0x00df
 157 }, {
 158         .name   = "dma high page",
 159         .start  = 0x0480,
 160         .end    = 0x048f
 161 } };
 162
 163 void __init isa_init_dma(dma_t *dma)
 164 {
 165         /*
 166          * Try to autodetect presence of an ISA DMA controller.
 167          * We do some minimal initialisation, and check that
 168          * channel 0's DMA address registers are writeable.
 169          */
 170         outb(0xff, 0x0d);
 171         outb(0xff, 0xda);
 172
 173         /*
 174          * Write high and low address, and then read them back
 175          * in the same order.
 176          */
 177         outb(0x55, 0x00);
 178         outb(0xaa, 0x00);
 179
 180         if (inb(0) == 0x55 && inb(0) == 0xaa) {
 181                 int channel, i;
 182
 183                 for (channel = 0; channel < 8; channel++) {
 184                         dma[channel].d_ops = &isa_dma_ops;
 185                         isa_disable_dma(channel, NULL);
 186                 }
 187
 188                 outb(0x40, 0x0b);
 189                 outb(0x41, 0x0b);
 190                 outb(0x42, 0x0b);
 191                 outb(0x43, 0x0b);
 192
 193                 outb(0xc0, 0xd6);
 194                 outb(0x41, 0xd6);
 195                 outb(0x42, 0xd6);
 196                 outb(0x43, 0xd6);
 197
 198                 outb(0, 0xd4);
 199
 200                 outb(0x10, 0x08);
 201                 outb(0x10, 0xd0);
 202
 203                 /*
 204                  * Is this correct?  According to my documentation, it
 205                  * doesn't appear to be.  It should be:
 206                  *  outb(0x3f, 0x40b); outb(0x3f, 0x4d6);
 207                  */
 208                 outb(0x30, 0x40b);
 209                 outb(0x31, 0x40b);
 210                 outb(0x32, 0x40b);
 211                 outb(0x33, 0x40b);
 212                 outb(0x31, 0x4d6);
 213                 outb(0x32, 0x4d6);
 214                 outb(0x33, 0x4d6);
 215
 216                 request_dma(DMA_ISA_CASCADE, "cascade");
 217
 218                 for (i = 0; i < ARRAY_SIZE(dma_resources); i++)
 219                         request_resource(&ioport_resource, dma_resources + i);
 220         }
 221 }