4 * The low level driver for the PAS Midi Interface.
7 * Copyright (C) by Hannu Savolainen 1993-1997
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
13 * Bartlomiej Zolnierkiewicz : Added __init to pas_init_mixer()
16 #include <linux/init.h>
17 #include "sound_config.h"
21 static int midi_busy = 0, input_opened = 0;
26 static unsigned char tmp_queue[256];
27 static volatile int qlen;
28 static volatile unsigned char qhead, qtail;
30 static void (*midi_input_intr) (int dev, unsigned char data);
32 static int pas_midi_open(int dev, int mode,
33 void (*input) (int dev, unsigned char data),
34 void (*output) (int dev)
46 * Reset input and output FIFO pointers
48 pas_write(0x20 | 0x40,
54 if ((err = pas_set_intr(0x10)) < 0)
60 * Enable input available and output FIFO empty interrupts
65 midi_input_intr = input;
67 if (mode == OPEN_READ || mode == OPEN_READWRITE)
69 ctrl |= 0x04; /* Enable input */
72 if (mode == OPEN_WRITE || mode == OPEN_READWRITE)
74 ctrl |= 0x08 | 0x10; /* Enable output */
76 pas_write(ctrl, 0x178b);
79 * Acknowledge any pending interrupts
82 pas_write(0xff, 0x1B88);
87 qlen = qhead = qtail = 0;
91 static void pas_midi_close(int dev)
95 * Reset FIFO pointers, disable intrs
97 pas_write(0x20 | 0x40, 0x178b);
99 pas_remove_intr(0x10);
103 static int dump_to_midi(unsigned char midi_byte)
107 fifo_space = ((x = pas_read(0x1B89)) >> 4) & 0x0f;
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.
117 if (fifo_space < 2 && fifo_space != 0) /* Full (almost) */
118 return 0; /* Ask upper layers to retry after some time */
120 pas_write(midi_byte, 0x178A);
125 static int pas_midi_out(int dev, unsigned char midi_byte)
131 * Drain the local queue first
137 while (qlen && dump_to_midi(tmp_queue[qhead]))
143 restore_flags(flags);
146 * Output the byte if the local queue is empty.
150 if (dump_to_midi(midi_byte))
154 * Put to the local queue
158 return 0; /* Local queue full */
163 tmp_queue[qtail] = midi_byte;
167 restore_flags(flags);
172 static int pas_midi_start_read(int dev)
177 static int pas_midi_end_read(int dev)
182 static void pas_midi_kick(int dev)
186 static int pas_buffer_status(int dev)
191 #define MIDI_SYNTH_NAME "Pro Audio Spectrum Midi"
192 #define MIDI_SYNTH_CAPS SYNTH_CAP_INPUT
193 #include "midi_synth.h"
195 static struct midi_operations pas_midi_operations =
198 info: {"Pro Audio Spectrum", 0, 0, SNDCARD_PAS},
199 converter: &std_midi_synth,
202 close: pas_midi_close,
203 outputc: pas_midi_out,
204 start_read: pas_midi_start_read,
205 end_read: pas_midi_end_read,
207 buffer_status: pas_buffer_status,
210 void __init pas_midi_init(void)
212 int dev = sound_alloc_mididev();
216 printk(KERN_WARNING "pas_midi_init: Too many midi devices detected\n");
219 std_midi_synth.midi_dev = my_dev = dev;
220 midi_devs[dev] = &pas_midi_operations;
225 void pas_midi_interrupt(void)
231 stat = pas_read(0x1B88);
233 if (stat & 0x04) /* Input data available */
235 incount = pas_read(0x1B89) & 0x0f; /* Input FIFO size */
239 for (i = 0; i < incount; i++)
242 midi_input_intr(my_dev, pas_read(0x178A));
244 pas_read(0x178A); /* Flush */
246 if (stat & (0x08 | 0x10))
251 while (qlen && dump_to_midi(tmp_queue[qhead]))
257 restore_flags(flags);
261 printk(KERN_WARNING "MIDI output overrun %x,%x\n", pas_read(0x1B89), stat);
263 pas_write(stat, 0x1B88); /* Acknowledge interrupts */