1 /*
2 * sound/oss/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 <linux/spinlock.h>
18 #include "sound_config.h"
19
20 #include "pas2.h"
21
22 extern spinlock_t pas_lock;
23
24 static int midi_busy, input_opened;
25 static int my_dev;
26
27 int pas2_mididev=-1;
28
29 static unsigned char tmp_queue[256];
30 static volatile int qlen;
31 static volatile unsigned char qhead, qtail;
32
33 static void (*midi_input_intr) (int dev, unsigned char data);
34
pas_midi_open(int dev,int mode,void (* input)(int dev,unsigned char data),void (* output)(int dev))35 static int pas_midi_open(int dev, int mode,
36 void (*input) (int dev, unsigned char data),
37 void (*output) (int dev)
38 )
39 {
40 int err;
41 unsigned long flags;
42 unsigned char ctrl;
43
44
45 if (midi_busy)
46 return -EBUSY;
47
48 /*
49 * Reset input and output FIFO pointers
50 */
51 pas_write(0x20 | 0x40,
52 0x178b);
53
54 spin_lock_irqsave(&pas_lock, flags);
55
56 if ((err = pas_set_intr(0x10)) < 0)
57 {
58 spin_unlock_irqrestore(&pas_lock, flags);
59 return err;
60 }
61 /*
62 * Enable input available and output FIFO empty interrupts
63 */
64
65 ctrl = 0;
66 input_opened = 0;
67 midi_input_intr = input;
68
69 if (mode == OPEN_READ || mode == OPEN_READWRITE)
70 {
71 ctrl |= 0x04; /* Enable input */
72 input_opened = 1;
73 }
74 if (mode == OPEN_WRITE || mode == OPEN_READWRITE)
75 {
76 ctrl |= 0x08 | 0x10; /* Enable output */
77 }
78 pas_write(ctrl, 0x178b);
79
80 /*
81 * Acknowledge any pending interrupts
82 */
83
84 pas_write(0xff, 0x1B88);
85
86 spin_unlock_irqrestore(&pas_lock, flags);
87
88 midi_busy = 1;
89 qlen = qhead = qtail = 0;
90 return 0;
91 }
92
pas_midi_close(int dev)93 static void pas_midi_close(int dev)
94 {
95
96 /*
97 * Reset FIFO pointers, disable intrs
98 */
99 pas_write(0x20 | 0x40, 0x178b);
100
101 pas_remove_intr(0x10);
102 midi_busy = 0;
103 }
104
dump_to_midi(unsigned char midi_byte)105 static int dump_to_midi(unsigned char midi_byte)
106 {
107 int fifo_space, x;
108
109 fifo_space = ((x = pas_read(0x1B89)) >> 4) & 0x0f;
110
111 /*
112 * The MIDI FIFO space register and it's documentation is nonunderstandable.
113 * There seem to be no way to differentiate between buffer full and buffer
114 * empty situations. For this reason we don't never write the buffer
115 * completely full. In this way we can assume that 0 (or is it 15)
116 * means that the buffer is empty.
117 */
118
119 if (fifo_space < 2 && fifo_space != 0) /* Full (almost) */
120 return 0; /* Ask upper layers to retry after some time */
121
122 pas_write(midi_byte, 0x178A);
123
124 return 1;
125 }
126
pas_midi_out(int dev,unsigned char midi_byte)127 static int pas_midi_out(int dev, unsigned char midi_byte)
128 {
129
130 unsigned long flags;
131
132 /*
133 * Drain the local queue first
134 */
135
136 spin_lock_irqsave(&pas_lock, flags);
137
138 while (qlen && dump_to_midi(tmp_queue[qhead]))
139 {
140 qlen--;
141 qhead++;
142 }
143
144 spin_unlock_irqrestore(&pas_lock, flags);
145
146 /*
147 * Output the byte if the local queue is empty.
148 */
149
150 if (!qlen)
151 if (dump_to_midi(midi_byte))
152 return 1;
153
154 /*
155 * Put to the local queue
156 */
157
158 if (qlen >= 256)
159 return 0; /* Local queue full */
160
161 spin_lock_irqsave(&pas_lock, flags);
162
163 tmp_queue[qtail] = midi_byte;
164 qlen++;
165 qtail++;
166
167 spin_unlock_irqrestore(&pas_lock, flags);
168
169 return 1;
170 }
171
pas_midi_start_read(int dev)172 static int pas_midi_start_read(int dev)
173 {
174 return 0;
175 }
176
pas_midi_end_read(int dev)177 static int pas_midi_end_read(int dev)
178 {
179 return 0;
180 }
181
pas_midi_kick(int dev)182 static void pas_midi_kick(int dev)
183 {
184 }
185
pas_buffer_status(int dev)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
pas_midi_init(void)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
pas_midi_interrupt(void)225 void pas_midi_interrupt(void)
226 {
227 unsigned char stat;
228 int i, incount;
229
230 stat = pas_read(0x1B88);
231
232 if (stat & 0x04) /* Input data available */
233 {
234 incount = pas_read(0x1B89) & 0x0f; /* Input FIFO size */
235 if (!incount)
236 incount = 16;
237
238 for (i = 0; i < incount; i++)
239 if (input_opened)
240 {
241 midi_input_intr(my_dev, pas_read(0x178A));
242 } else
243 pas_read(0x178A); /* Flush */
244 }
245 if (stat & (0x08 | 0x10))
246 {
247 spin_lock(&pas_lock);/* called in irq context */
248
249 while (qlen && dump_to_midi(tmp_queue[qhead]))
250 {
251 qlen--;
252 qhead++;
253 }
254
255 spin_unlock(&pas_lock);
256 }
257 if (stat & 0x40)
258 {
259 printk(KERN_WARNING "MIDI output overrun %x,%x\n", pas_read(0x1B89), stat);
260 }
261 pas_write(stat, 0x1B88); /* Acknowledge interrupts */
262 }
263