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
  23 #include <asm/dma.h>
  24 #include <asm/io.h>
  25
  26 #include <asm/mach/dma.h>
  27
  28 #define ISA_DMA_MODE_READ       0x44
  29 #define ISA_DMA_MODE_WRITE      0x48
  30 #define ISA_DMA_MODE_CASCADE    0xc0
  31 #define ISA_DMA_AUTOINIT        0x10
  32
  33 #define ISA_DMA_MASK            0
  34 #define ISA_DMA_MODE            1
  35 #define ISA_DMA_CLRFF           2
  36 #define ISA_DMA_PGHI            3
  37 #define ISA_DMA_PGLO            4
  38 #define ISA_DMA_ADDR            5
  39 #define ISA_DMA_COUNT           6
  40
  41 static unsigned int isa_dma_port[8][7] = {
  42         /* MASK   MODE   CLRFF  PAGE_HI PAGE_LO ADDR COUNT */
  43         {  0x0a,  0x0b,  0x0c,  0x487,  0x087,  0x00, 0x01 },
  44         {  0x0a,  0x0b,  0x0c,  0x483,  0x083,  0x02, 0x03 },
  45         {  0x0a,  0x0b,  0x0c,  0x481,  0x081,  0x04, 0x05 },
  46         {  0x0a,  0x0b,  0x0c,  0x482,  0x082,  0x06, 0x07 },
  47         {  0xd4,  0xd6,  0xd8,  0x000,  0x000,  0xc0, 0xc2 },
  48         {  0xd4,  0xd6,  0xd8,  0x48b,  0x08b,  0xc4, 0xc6 },
  49         {  0xd4,  0xd6,  0xd8,  0x489,  0x089,  0xc8, 0xca },
  50         {  0xd4,  0xd6,  0xd8,  0x48a,  0x08a,  0xcc, 0xce }
  51 };
  52
  53 static int isa_get_dma_residue(dmach_t channel, dma_t *dma)
  54 {
  55         unsigned int io_port = isa_dma_port[channel][ISA_DMA_COUNT];
  56         int count;
  57
  58         count = 1 + inb(io_port);
  59         count |= inb(io_port) << 8;
  60
  61         return channel < 4 ? count : (count << 1);
  62 }
  63
  64 static void isa_enable_dma(dmach_t channel, dma_t *dma)
  65 {
  66         if (dma->invalid) {
  67                 unsigned long address, length;
  68                 unsigned int mode;
  69                 enum dma_data_direction direction;
  70
  71                 mode = channel & 3;
  72                 switch (dma->dma_mode & DMA_MODE_MASK) {
  73                 case DMA_MODE_READ:
  74                         mode |= ISA_DMA_MODE_READ;
  75                         direction = DMA_FROM_DEVICE;
  76                         break;
  77
  78                 case DMA_MODE_WRITE:
  79                         mode |= ISA_DMA_MODE_WRITE;
  80                         direction = DMA_TO_DEVICE;
  81                         break;
  82
  83                 case DMA_MODE_CASCADE:
  84                         mode |= ISA_DMA_MODE_CASCADE;
  85                         direction = DMA_BIDIRECTIONAL;
  86                         break;
  87
  88                 default:
  89                         direction = DMA_NONE;
  90                         break;
  91                 }
  92
  93                 if (!dma->sg) {
  94                         /*
  95                          * Cope with ISA-style drivers which expect cache
  96                          * coherence.
  97                          */
  98                         dma->sg = &dma->buf;
  99                         dma->sgcount = 1;
 100                         dma->buf.length = dma->count;
 101                         dma->buf.dma_address = dma_map_single(NULL,
 102                                 dma->addr, dma->count,
 103                                 direction);
 104                 }
 105
 106                 address = dma->buf.dma_address;
 107                 length  = dma->buf.length - 1;
 108
 109                 outb(address >> 16, isa_dma_port[channel][ISA_DMA_PGLO]);
 110                 outb(address >> 24, isa_dma_port[channel][ISA_DMA_PGHI]);
 111
 112                 if (channel >= 4) {
 113                         address >>= 1;
 114                         length >>= 1;
 115                 }
 116
 117                 outb(0, isa_dma_port[channel][ISA_DMA_CLRFF]);
 118
 119                 outb(address, isa_dma_port[channel][ISA_DMA_ADDR]);
 120                 outb(address >> 8, isa_dma_port[channel][ISA_DMA_ADDR]);
 121
 122                 outb(length, isa_dma_port[channel][ISA_DMA_COUNT]);
 123                 outb(length >> 8, isa_dma_port[channel][ISA_DMA_COUNT]);
 124
 125                 if (dma->dma_mode & DMA_AUTOINIT)
 126                         mode |= ISA_DMA_AUTOINIT;
 127
 128                 outb(mode, isa_dma_port[channel][ISA_DMA_MODE]);
 129                 dma->invalid = 0;
 130         }
 131         outb(channel & 3, isa_dma_port[channel][ISA_DMA_MASK]);
 132 }
 133
 134 static void isa_disable_dma(dmach_t channel, dma_t *dma)
 135 {
 136         outb(channel | 4, isa_dma_port[channel][ISA_DMA_MASK]);
 137 }
 138
 139 static struct dma_ops isa_dma_ops = {
 140         .type           = "ISA",
 141         .enable         = isa_enable_dma,
 142         .disable        = isa_disable_dma,
 143         .residue        = isa_get_dma_residue,
 144 };
 145
 146 static struct resource dma_resources[] = { {
 147         .name   = "dma1",
 148         .start  = 0x0000,
 149         .end    = 0x000f
 150 }, {
 151         .name   = "dma low page",
 152         .start  = 0x0080,
 153         .end    = 0x008f
 154 }, {
 155         .name   = "dma2",
 156         .start  = 0x00c0,
 157         .end    = 0x00df
 158 }, {
 159         .name   = "dma high page",
 160         .start  = 0x0480,
 161         .end    = 0x048f
 162 } };
 163
 164 void __init isa_init_dma(dma_t *dma)
 165 {
 166         /*
 167          * Try to autodetect presence of an ISA DMA controller.
 168          * We do some minimal initialisation, and check that
 169          * channel 0's DMA address registers are writeable.
 170          */
 171         outb(0xff, 0x0d);
 172         outb(0xff, 0xda);
 173
 174         /*
 175          * Write high and low address, and then read them back
 176          * in the same order.
 177          */
 178         outb(0x55, 0x00);
 179         outb(0xaa, 0x00);
 180
 181         if (inb(0) == 0x55 && inb(0) == 0xaa) {
 182                 int channel, i;
 183
 184                 for (channel = 0; channel < 8; channel++) {
 185                         dma[channel].d_ops = &isa_dma_ops;
 186                         isa_disable_dma(channel, NULL);
 187                 }
 188
 189                 outb(0x40, 0x0b);
 190                 outb(0x41, 0x0b);
 191                 outb(0x42, 0x0b);
 192                 outb(0x43, 0x0b);
 193
 194                 outb(0xc0, 0xd6);
 195                 outb(0x41, 0xd6);
 196                 outb(0x42, 0xd6);
 197                 outb(0x43, 0xd6);
 198
 199                 outb(0, 0xd4);
 200
 201                 outb(0x10, 0x08);
 202                 outb(0x10, 0xd0);
 203
 204                 /*
 205                  * Is this correct?  According to my documentation, it
 206                  * doesn't appear to be.  It should be:
 207                  *  outb(0x3f, 0x40b); outb(0x3f, 0x4d6);
 208                  */
 209                 outb(0x30, 0x40b);
 210                 outb(0x31, 0x40b);
 211                 outb(0x32, 0x40b);
 212                 outb(0x33, 0x40b);
 213                 outb(0x31, 0x4d6);
 214                 outb(0x32, 0x4d6);
 215                 outb(0x33, 0x4d6);
 216
 217                 request_dma(DMA_ISA_CASCADE, "cascade");
 218
 219                 for (i = 0; i < ARRAY_SIZE(dma_resources); i++)
 220                         request_resource(&ioport_resource, dma_resources + i);
 221         }
 222 }