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