1 /*
2 * sound/pas2_midi.c
3 *
4 * The low level driver for the PAS Midi Interface.
5 */
6 /*
7 * Copyright (C) by Hannu Savolainen 1993-1997
8 *
9 * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
10 * Version 2 (June 1991). See the "COPYING" file distributed with this software
11 * for more info.
12 *
13 * Bartlomiej Zolnierkiewicz : Added __init to pas_init_mixer()
14 */
15
16 #include <linux/init.h>
17 #include "sound_config.h"
18
19 #include "pas2.h"
20
21 static int midi_busy = 0, input_opened = 0;
22 static int my_dev;
23
24 int pas2_mididev=-1;
25
26 static unsigned char tmp_queue[256];
27 static volatile int qlen;
28 static volatile unsigned char qhead, qtail;
29
30 static void (*midi_input_intr) (int dev, unsigned char data);
31
32 static int pas_midi_open(int dev, int mode,
33 void (*input) (int dev, unsigned char data),
34 void (*output) (int dev)
35 )
36 {
37 int err;
38 unsigned long flags;
39 unsigned char ctrl;
40
41
42 if (midi_busy)
43 return -EBUSY;
44
45 /*
46 * Reset input and output FIFO pointers
47 */
48 pas_write(0x20 | 0x40,
49 0x178b);
50
51 save_flags(flags);
52 cli();
53
54 if ((err = pas_set_intr(0x10)) < 0)
55 {
56 restore_flags(flags);
57 return err;
58 }
59 /*
60 * Enable input available and output FIFO empty interrupts
61 */
62
63 ctrl = 0;
64 input_opened = 0;
65 midi_input_intr = input;
66
67 if (mode == OPEN_READ || mode == OPEN_READWRITE)
68 {
69 ctrl |= 0x04; /* Enable input */
70 input_opened = 1;
71 }
72 if (mode == OPEN_WRITE || mode == OPEN_READWRITE)
73 {
74 ctrl |= 0x08 | 0x10; /* Enable output */
75 }
76 pas_write(ctrl, 0x178b);
77
78 /*
79 * Acknowledge any pending interrupts
80 */
81
82 pas_write(0xff, 0x1B88);
83
84 restore_flags(flags);
85
86 midi_busy = 1;
87 qlen = qhead = qtail = 0;
88 return 0;
89 }
90
91 static void pas_midi_close(int dev)
92 {
93
94 /*
95 * Reset FIFO pointers, disable intrs
96 */
97 pas_write(0x20 | 0x40, 0x178b);
98
99 pas_remove_intr(0x10);
100 midi_busy = 0;
101 }
102
103 static int dump_to_midi(unsigned char midi_byte)
104 {
105 int fifo_space, x;
106
107 fifo_space = ((x = pas_read(0x1B89)) >> 4) & 0x0f;
108
109 /*
110 * The MIDI FIFO space register and it's documentation is nonunderstandable.
111 * There seem to be no way to differentiate between buffer full and buffer
112 * empty situations. For this reason we don't never write the buffer
113 * completely full. In this way we can assume that 0 (or is it 15)
114 * means that the buffer is empty.
115 */
116
117 if (fifo_space < 2 && fifo_space != 0) /* Full (almost) */
118 return 0; /* Ask upper layers to retry after some time */
119
120 pas_write(midi_byte, 0x178A);
121
122 return 1;
123 }
124
125 static int pas_midi_out(int dev, unsigned char midi_byte)
126 {
127
128 unsigned long flags;
129
130 /*
131 * Drain the local queue first
132 */
133
134 save_flags(flags);
135 cli();
136
137 while (qlen && dump_to_midi(tmp_queue[qhead]))
138 {
139 qlen--;
140 qhead++;
141 }
142
143 restore_flags(flags);
144
145 /*
146 * Output the byte if the local queue is empty.
147 */
148
149 if (!qlen)
150 if (dump_to_midi(midi_byte))
151 return 1;
152
153 /*
154 * Put to the local queue
155 */
156
157 if (qlen >= 256)
158 return 0; /* Local queue full */
159
160 save_flags(flags);
161 cli();
162
163 tmp_queue[qtail] = midi_byte;
164 qlen++;
165 qtail++;
166
167 restore_flags(flags);
168
169 return 1;
170 }
171
172 static int pas_midi_start_read(int dev)
173 {
174 return 0;
175 }
176
177 static int pas_midi_end_read(int dev)
178 {
179 return 0;
180 }
181
182 static void pas_midi_kick(int dev)
183 {
184 }
185
186 static int pas_buffer_status(int dev)
187 {
188 return qlen;
189 }
190
191 #define MIDI_SYNTH_NAME "Pro Audio Spectrum Midi"
192 #define MIDI_SYNTH_CAPS SYNTH_CAP_INPUT
193 #include "midi_synth.h"
194
195 static struct midi_operations pas_midi_operations =
196 {
197 owner: THIS_MODULE,
198 info: {"Pro Audio Spectrum", 0, 0, SNDCARD_PAS},
199 converter: &std_midi_synth,
200 in_info: {0},
201 open: pas_midi_open,
202 close: pas_midi_close,
203 outputc: pas_midi_out,
204 start_read: pas_midi_start_read,
205 end_read: pas_midi_end_read,
206 kick: pas_midi_kick,
207 buffer_status: pas_buffer_status,
208 };
209
210 void __init pas_midi_init(void)
211 {
212 int dev = sound_alloc_mididev();
213
214 if (dev == -1)
215 {
216 printk(KERN_WARNING "pas_midi_init: Too many midi devices detected\n");
217 return;
218 }
219 std_midi_synth.midi_dev = my_dev = dev;
220 midi_devs[dev] = &pas_midi_operations;
221 pas2_mididev = dev;
222 sequencer_init();
223 }
224
225 void pas_midi_interrupt(void)
226 {
227 unsigned char stat;
228 int i, incount;
229 unsigned long flags;
230
231 stat = pas_read(0x1B88);
232
233 if (stat & 0x04) /* Input data available */
234 {
235 incount = pas_read(0x1B89) & 0x0f; /* Input FIFO size */
236 if (!incount)
237 incount = 16;
238
239 for (i = 0; i < incount; i++)
240 if (input_opened)
241 {
242 midi_input_intr(my_dev, pas_read(0x178A));
243 } else
244 pas_read(0x178A); /* Flush */
245 }
246 if (stat & (0x08 | 0x10))
247 {
248 save_flags(flags);
249 cli();
250
251 while (qlen && dump_to_midi(tmp_queue[qhead]))
252 {
253 qlen--;
254 qhead++;
255 }
256
257 restore_flags(flags);
258 }
259 if (stat & 0x40)
260 {
261 printk(KERN_WARNING "MIDI output overrun %x,%x\n", pas_read(0x1B89), stat);
262 }
263 pas_write(stat, 0x1B88); /* Acknowledge interrupts */
264 }
265
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