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dma-isa.c
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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;
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  */
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  printk(KERN_ERR "ISADMA%u: unable to register: %d\n",
217  chan, ret);
218  }
219 
220  request_dma(DMA_ISA_CASCADE, "cascade");
221  }
222 }