1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 1999-2000 Russell King
4 *
5 * ISA DMA primitives
6 * Taken from various sources, including:
7 * linux/include/asm/dma.h: Defines for using and allocating dma channels.
8 * Written by Hennus Bergman, 1992.
9 * High DMA channel support & info by Hannu Savolainen and John Boyd,
10 * Nov. 1992.
11 * arch/arm/kernel/dma-ebsa285.c
12 * Copyright (C) 1998 Phil Blundell
13 */
14 #include <linux/dma-map-ops.h>
15 #include <linux/ioport.h>
16 #include <linux/init.h>
17 #include <linux/dma-mapping.h>
18 #include <linux/io.h>
19
20 #include <asm/dma.h>
21 #include <asm/mach/dma.h>
22 #include <asm/hardware/dec21285.h>
23
24 #define ISA_DMA_MASK 0
25 #define ISA_DMA_MODE 1
26 #define ISA_DMA_CLRFF 2
27 #define ISA_DMA_PGHI 3
28 #define ISA_DMA_PGLO 4
29 #define ISA_DMA_ADDR 5
30 #define ISA_DMA_COUNT 6
31
32 static unsigned int isa_dma_port[8][7] = {
33 /* MASK MODE CLRFF PAGE_HI PAGE_LO ADDR COUNT */
34 { 0x0a, 0x0b, 0x0c, 0x487, 0x087, 0x00, 0x01 },
35 { 0x0a, 0x0b, 0x0c, 0x483, 0x083, 0x02, 0x03 },
36 { 0x0a, 0x0b, 0x0c, 0x481, 0x081, 0x04, 0x05 },
37 { 0x0a, 0x0b, 0x0c, 0x482, 0x082, 0x06, 0x07 },
38 { 0xd4, 0xd6, 0xd8, 0x000, 0x000, 0xc0, 0xc2 },
39 { 0xd4, 0xd6, 0xd8, 0x48b, 0x08b, 0xc4, 0xc6 },
40 { 0xd4, 0xd6, 0xd8, 0x489, 0x089, 0xc8, 0xca },
41 { 0xd4, 0xd6, 0xd8, 0x48a, 0x08a, 0xcc, 0xce }
42 };
43
44 static int isa_get_dma_residue(unsigned int chan, dma_t *dma)
45 {
46 unsigned int io_port = isa_dma_port[chan][ISA_DMA_COUNT];
47 int count;
48
49 count = 1 + inb(io_port);
50 count |= inb(io_port) << 8;
51
52 return chan < 4 ? count : (count << 1);
53 }
54
55 static struct device isa_dma_dev = {
56 .init_name = "fallback device",
57 .coherent_dma_mask = ~(dma_addr_t)0,
58 .dma_mask = &isa_dma_dev.coherent_dma_mask,
59 };
60
61 static void isa_enable_dma(unsigned int chan, dma_t *dma)
62 {
63 if (dma->invalid) {
64 unsigned long address, length;
65 unsigned int mode;
66 enum dma_data_direction direction;
67
68 mode = (chan & 3) | dma->dma_mode;
69 switch (dma->dma_mode & DMA_MODE_MASK) {
70 case DMA_MODE_READ:
71 direction = DMA_FROM_DEVICE;
72 break;
73
74 case DMA_MODE_WRITE:
75 direction = DMA_TO_DEVICE;
76 break;
77
78 case DMA_MODE_CASCADE:
79 direction = DMA_BIDIRECTIONAL;
80 break;
81
82 default:
83 direction = DMA_NONE;
84 break;
85 }
86
87 if (!dma->sg) {
88 /*
89 * Cope with ISA-style drivers which expect cache
90 * coherence.
91 */
92 dma->sg = &dma->buf;
93 dma->sgcount = 1;
94 dma->buf.length = dma->count;
95 dma->buf.dma_address = dma_map_single(&isa_dma_dev,
96 dma->addr, dma->count,
97 direction);
98 }
99
100 address = dma->buf.dma_address;
101 length = dma->buf.length - 1;
102
103 outb(address >> 16, isa_dma_port[chan][ISA_DMA_PGLO]);
104 outb(address >> 24, isa_dma_port[chan][ISA_DMA_PGHI]);
105
106 if (chan >= 4) {
107 address >>= 1;
108 length >>= 1;
109 }
110
111 outb(0, isa_dma_port[chan][ISA_DMA_CLRFF]);
112
113 outb(address, isa_dma_port[chan][ISA_DMA_ADDR]);
114 outb(address >> 8, isa_dma_port[chan][ISA_DMA_ADDR]);
115
116 outb(length, isa_dma_port[chan][ISA_DMA_COUNT]);
117 outb(length >> 8, isa_dma_port[chan][ISA_DMA_COUNT]);
118
119 outb(mode, isa_dma_port[chan][ISA_DMA_MODE]);
120 dma->invalid = 0;
121 }
122 outb(chan & 3, isa_dma_port[chan][ISA_DMA_MASK]);
123 }
124
125 static void isa_disable_dma(unsigned int chan, dma_t *dma)
126 {
127 outb(chan | 4, isa_dma_port[chan][ISA_DMA_MASK]);
128 }
129
130 static struct dma_ops isa_dma_ops = {
131 .type = "ISA",
132 .enable = isa_enable_dma,
133 .disable = isa_disable_dma,
134 .residue = isa_get_dma_residue,
135 };
136
137 static struct resource dma_resources[] = { {
138 .name = "dma1",
139 .start = 0x0000,
140 .end = 0x000f
141 }, {
142 .name = "dma low page",
143 .start = 0x0080,
144 .end = 0x008f
145 }, {
146 .name = "dma2",
147 .start = 0x00c0,
148 .end = 0x00df
149 }, {
150 .name = "dma high page",
151 .start = 0x0480,
152 .end = 0x048f
153 } };
154
155 static dma_t isa_dma[8];
156
157 /*
158 * ISA DMA always starts at channel 0
159 */
160 static int __init isa_dma_init(void)
161 {
162 /*
163 * Try to autodetect presence of an ISA DMA controller.
164 * We do some minimal initialisation, and check that
165 * channel 0's DMA address registers are writeable.
166 */
167 outb(0xff, 0x0d);
168 outb(0xff, 0xda);
169
170 /*
171 * Write high and low address, and then read them back
172 * in the same order.
173 */
174 outb(0x55, 0x00);
175 outb(0xaa, 0x00);
176
177 if (inb(0) == 0x55 && inb(0) == 0xaa) {
178 unsigned int chan, i;
179
180 for (chan = 0; chan < 8; chan++) {
181 isa_dma[chan].d_ops = &isa_dma_ops;
182 isa_disable_dma(chan, NULL);
183 }
184
185 outb(0x40, 0x0b);
186 outb(0x41, 0x0b);
187 outb(0x42, 0x0b);
188 outb(0x43, 0x0b);
189
190 outb(0xc0, 0xd6);
191 outb(0x41, 0xd6);
192 outb(0x42, 0xd6);
193 outb(0x43, 0xd6);
194
195 outb(0, 0xd4);
196
197 outb(0x10, 0x08);
198 outb(0x10, 0xd0);
199
200 /*
201 * Is this correct? According to my documentation, it
202 * doesn't appear to be. It should be:
203 * outb(0x3f, 0x40b); outb(0x3f, 0x4d6);
204 */
205 outb(0x30, 0x40b);
206 outb(0x31, 0x40b);
207 outb(0x32, 0x40b);
208 outb(0x33, 0x40b);
209 outb(0x31, 0x4d6);
210 outb(0x32, 0x4d6);
211 outb(0x33, 0x4d6);
212
213 for (i = 0; i < ARRAY_SIZE(dma_resources); i++)
214 request_resource(&ioport_resource, dma_resources + i);
215
216 for (chan = 0; chan < 8; chan++) {
217 int ret = isa_dma_add(chan, &isa_dma[chan]);
218 if (ret)
219 pr_err("ISADMA%u: unable to register: %d\n",
220 chan, ret);
221 }
222
223 request_dma(DMA_ISA_CASCADE, "cascade");
224 }
225
226 dma_direct_set_offset(&isa_dma_dev, PHYS_OFFSET, BUS_OFFSET, SZ_256M);
227
228 return 0;
229 }
230 core_initcall(isa_dma_init);
231
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.