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2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
8852ecd9 LV |
2 | /* |
3 | * low-level functions for the SWIM floppy controller | |
4 | * | |
5 | * needs assembly language because is very timing dependent | |
6 | * this controller exists only on macintosh 680x0 based | |
7 | * | |
8 | * Copyright (C) 2004,2008 Laurent Vivier <Laurent@lvivier.info> | |
9 | * | |
10 | * based on Alastair Bridgewater SWIM analysis, 2001 | |
11 | * based on netBSD IWM driver (c) 1997, 1998 Hauke Fath. | |
12 | * | |
8852ecd9 LV |
13 | * 2004-08-21 (lv) - Initial implementation |
14 | * 2008-11-05 (lv) - add get_swim_mode | |
15 | */ | |
16 | ||
17 | .equ write_data, 0x0000 | |
18 | .equ write_mark, 0x0200 | |
19 | .equ write_CRC, 0x0400 | |
20 | .equ write_parameter,0x0600 | |
21 | .equ write_phase, 0x0800 | |
22 | .equ write_setup, 0x0a00 | |
23 | .equ write_mode0, 0x0c00 | |
24 | .equ write_mode1, 0x0e00 | |
25 | .equ read_data, 0x1000 | |
26 | .equ read_mark, 0x1200 | |
27 | .equ read_error, 0x1400 | |
28 | .equ read_parameter, 0x1600 | |
29 | .equ read_phase, 0x1800 | |
30 | .equ read_setup, 0x1a00 | |
31 | .equ read_status, 0x1c00 | |
32 | .equ read_handshake, 0x1e00 | |
33 | ||
34 | .equ o_side, 0 | |
35 | .equ o_track, 1 | |
36 | .equ o_sector, 2 | |
37 | .equ o_size, 3 | |
38 | .equ o_crc0, 4 | |
39 | .equ o_crc1, 5 | |
40 | ||
41 | .equ seek_time, 30000 | |
42 | .equ max_retry, 40 | |
43 | .equ sector_size, 512 | |
44 | ||
45 | .global swim_read_sector_header | |
46 | swim_read_sector_header: | |
47 | link %a6, #0 | |
48 | moveml %d1-%d5/%a0-%a4,%sp@- | |
49 | movel %a6@(0x0c), %a4 | |
50 | bsr mfm_read_addrmark | |
51 | moveml %sp@+, %d1-%d5/%a0-%a4 | |
52 | unlk %a6 | |
53 | rts | |
54 | ||
55 | sector_address_mark: | |
56 | .byte 0xa1, 0xa1, 0xa1, 0xfe | |
57 | sector_data_mark: | |
58 | .byte 0xa1, 0xa1, 0xa1, 0xfb | |
59 | ||
60 | mfm_read_addrmark: | |
61 | movel %a6@(0x08), %a3 | |
62 | lea %a3@(read_handshake), %a2 | |
63 | lea %a3@(read_mark), %a3 | |
64 | moveq #-1, %d0 | |
65 | movew #seek_time, %d2 | |
66 | ||
67 | wait_header_init: | |
68 | tstb %a3@(read_error - read_mark) | |
69 | moveb #0x18, %a3@(write_mode0 - read_mark) | |
70 | moveb #0x01, %a3@(write_mode1 - read_mark) | |
71 | moveb #0x01, %a3@(write_mode0 - read_mark) | |
72 | tstb %a3@(read_error - read_mark) | |
73 | moveb #0x08, %a3@(write_mode1 - read_mark) | |
74 | ||
75 | lea sector_address_mark, %a0 | |
76 | moveq #3, %d1 | |
77 | ||
78 | wait_addr_mark_byte: | |
79 | ||
80 | tstb %a2@ | |
81 | dbmi %d2, wait_addr_mark_byte | |
82 | bpl header_exit | |
83 | ||
84 | moveb %a3@, %d3 | |
85 | cmpb %a0@+, %d3 | |
86 | dbne %d1, wait_addr_mark_byte | |
87 | bne wait_header_init | |
88 | ||
89 | moveq #max_retry, %d2 | |
90 | ||
91 | amark0: tstb %a2@ | |
92 | dbmi %d2, amark0 | |
93 | bpl signal_nonyb | |
94 | ||
95 | moveb %a3@, %a4@(o_track) | |
96 | ||
97 | moveq #max_retry, %d2 | |
98 | ||
99 | amark1: tstb %a2@ | |
100 | dbmi %d2, amark1 | |
101 | bpl signal_nonyb | |
102 | ||
103 | moveb %a3@, %a4@(o_side) | |
104 | ||
105 | moveq #max_retry, %d2 | |
106 | ||
107 | amark2: tstb %a2@ | |
108 | dbmi %d2, amark2 | |
109 | bpl signal_nonyb | |
110 | ||
111 | moveb %a3@, %a4@(o_sector) | |
112 | ||
113 | moveq #max_retry, %d2 | |
114 | ||
115 | amark3: tstb %a2@ | |
116 | dbmi %d2, amark3 | |
117 | bpl signal_nonyb | |
118 | ||
119 | moveb %a3@, %a4@(o_size) | |
120 | ||
121 | moveq #max_retry, %d2 | |
122 | ||
123 | crc0: tstb %a2@ | |
124 | dbmi %d2, crc0 | |
125 | bpl signal_nonyb | |
126 | ||
127 | moveb %a3@, %a4@(o_crc0) | |
128 | ||
129 | moveq #max_retry, %d2 | |
130 | ||
131 | crc1: tstb %a2@ | |
132 | dbmi %d2, crc1 | |
133 | bpl signal_nonyb | |
134 | ||
135 | moveb %a3@, %a4@(o_crc1) | |
136 | ||
137 | tstb %a3@(read_error - read_mark) | |
138 | ||
139 | header_exit: | |
140 | moveq #0, %d0 | |
141 | moveb #0x18, %a3@(write_mode0 - read_mark) | |
142 | rts | |
143 | signal_nonyb: | |
144 | moveq #-1, %d0 | |
145 | moveb #0x18, %a3@(write_mode0 - read_mark) | |
146 | rts | |
147 | ||
148 | .global swim_read_sector_data | |
149 | swim_read_sector_data: | |
150 | link %a6, #0 | |
151 | moveml %d1-%d5/%a0-%a5,%sp@- | |
152 | movel %a6@(0x0c), %a4 | |
153 | bsr mfm_read_data | |
154 | moveml %sp@+, %d1-%d5/%a0-%a5 | |
155 | unlk %a6 | |
156 | rts | |
157 | ||
158 | mfm_read_data: | |
159 | movel %a6@(0x08), %a3 | |
160 | lea %a3@(read_handshake), %a2 | |
161 | lea %a3@(read_data), %a5 | |
162 | lea %a3@(read_mark), %a3 | |
163 | movew #seek_time, %d2 | |
164 | ||
165 | wait_data_init: | |
166 | tstb %a3@(read_error - read_mark) | |
167 | moveb #0x18, %a3@(write_mode0 - read_mark) | |
168 | moveb #0x01, %a3@(write_mode1 - read_mark) | |
169 | moveb #0x01, %a3@(write_mode0 - read_mark) | |
170 | tstb %a3@(read_error - read_mark) | |
171 | moveb #0x08, %a3@(write_mode1 - read_mark) | |
172 | ||
173 | lea sector_data_mark, %a0 | |
174 | moveq #3, %d1 | |
175 | ||
176 | /* wait data address mark */ | |
177 | ||
178 | wait_data_mark_byte: | |
179 | ||
180 | tstb %a2@ | |
181 | dbmi %d2, wait_data_mark_byte | |
182 | bpl data_exit | |
183 | ||
184 | moveb %a3@, %d3 | |
185 | cmpb %a0@+, %d3 | |
186 | dbne %d1, wait_data_mark_byte | |
187 | bne wait_data_init | |
188 | ||
189 | /* read data */ | |
190 | ||
191 | tstb %a3@(read_error - read_mark) | |
192 | ||
193 | movel #sector_size-1, %d4 /* sector size */ | |
194 | read_new_data: | |
195 | movew #max_retry, %d2 | |
196 | read_data_loop: | |
197 | moveb %a2@, %d5 | |
198 | andb #0xc0, %d5 | |
199 | dbne %d2, read_data_loop | |
200 | beq data_exit | |
201 | moveb %a5@, %a4@+ | |
202 | andb #0x40, %d5 | |
203 | dbne %d4, read_new_data | |
204 | beq exit_loop | |
205 | moveb %a5@, %a4@+ | |
206 | dbra %d4, read_new_data | |
207 | exit_loop: | |
208 | ||
209 | /* read CRC */ | |
210 | ||
211 | movew #max_retry, %d2 | |
212 | data_crc0: | |
213 | ||
214 | tstb %a2@ | |
215 | dbmi %d2, data_crc0 | |
216 | bpl data_exit | |
217 | ||
218 | moveb %a3@, %d5 | |
219 | ||
220 | moveq #max_retry, %d2 | |
221 | ||
222 | data_crc1: | |
223 | ||
224 | tstb %a2@ | |
225 | dbmi %d2, data_crc1 | |
226 | bpl data_exit | |
227 | ||
228 | moveb %a3@, %d5 | |
229 | ||
230 | tstb %a3@(read_error - read_mark) | |
231 | ||
232 | moveb #0x18, %a3@(write_mode0 - read_mark) | |
233 | ||
234 | /* return number of bytes read */ | |
235 | ||
236 | movel #sector_size, %d0 | |
237 | addw #1, %d4 | |
238 | subl %d4, %d0 | |
239 | rts | |
240 | data_exit: | |
241 | moveb #0x18, %a3@(write_mode0 - read_mark) | |
242 | moveq #-1, %d0 | |
243 | rts |