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/*
* sound/pas2_midi.c
*
* The low level driver for the PAS Midi Interface.
*/
/*
* Copyright (C) by Hannu Savolainen 1993-1996
*
* OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
* Version 2 (June 1991). See the "COPYING" file distributed with this software
* for more info.
*/
#include <linux/config.h>
#include "sound_config.h"
#if defined(CONFIG_PAS) && defined(CONFIG_MIDI)
static int midi_busy = 0, input_opened = 0;
static int my_dev;
static unsigned char tmp_queue[256];
static volatile int qlen;
static volatile unsigned char qhead, qtail;
static void (*midi_input_intr) (int dev, unsigned char data);
static int
pas_midi_open (int dev, int mode,
void (*input) (int dev, unsigned char data),
void (*output) (int dev)
)
{
int err;
unsigned long flags;
unsigned char ctrl;
if (midi_busy)
{
printk ("PAS2: Midi busy\n");
return -EBUSY;
}
/*
* Reset input and output FIFO pointers
*/
pas_write (0x20 | 0x40,
0x178b);
save_flags (flags);
cli ();
if ((err = pas_set_intr (0x10)) < 0)
return err;
/*
* Enable input available and output FIFO empty interrupts
*/
ctrl = 0;
input_opened = 0;
midi_input_intr = input;
if (mode == OPEN_READ || mode == OPEN_READWRITE)
{
ctrl |= 0x04; /* Enable input */
input_opened = 1;
}
if (mode == OPEN_WRITE || mode == OPEN_READWRITE)
{
ctrl |= 0x08 | 0x10; /* Enable output */
}
pas_write (ctrl, 0x178b);
/*
* Acknowledge any pending interrupts
*/
pas_write (0xff, 0x1B88);
restore_flags (flags);
midi_busy = 1;
qlen = qhead = qtail = 0;
return 0;
}
static void
pas_midi_close (int dev)
{
/*
* Reset FIFO pointers, disable intrs
*/
pas_write (0x20 | 0x40, 0x178b);
pas_remove_intr (0x10);
midi_busy = 0;
}
static int
dump_to_midi (unsigned char midi_byte)
{
int fifo_space, x;
fifo_space = ((x = pas_read (0x1B89)) >> 4) & 0x0f;
/*
* The MIDI FIFO space register and it's documentation is nonunderstandable.
* There seem to be no way to differentiate between buffer full and buffer
* empty situations. For this reason we don't never write the buffer
* completely full. In this way we can assume that 0 (or is it 15)
* means that the buffer is empty.
*/
if (fifo_space < 2 && fifo_space != 0) /* Full (almost) */
{
return 0; /* Ask upper layers to retry after some time */
}
pas_write (midi_byte, 0x178A);
return 1;
}
static int
pas_midi_out (int dev, unsigned char midi_byte)
{
unsigned long flags;
/*
* Drain the local queue first
*/
save_flags (flags);
cli ();
while (qlen && dump_to_midi (tmp_queue[qhead]))
{
qlen--;
qhead++;
}
restore_flags (flags);
/*
* Output the byte if the local queue is empty.
*/
if (!qlen)
if (dump_to_midi (midi_byte))
return 1;
/*
* Put to the local queue
*/
if (qlen >= 256)
return 0; /* Local queue full */
save_flags (flags);
cli ();
tmp_queue[qtail] = midi_byte;
qlen++;
qtail++;
restore_flags (flags);
return 1;
}
static int
pas_midi_start_read (int dev)
{
return 0;
}
static int
pas_midi_end_read (int dev)
{
return 0;
}
static int
pas_midi_ioctl (int dev, unsigned cmd, caddr_t arg)
{
return -EINVAL;
}
static void
pas_midi_kick (int dev)
{
}
static int
pas_buffer_status (int dev)
{
return qlen;
}
#define MIDI_SYNTH_NAME "Pro Audio Spectrum Midi"
#define MIDI_SYNTH_CAPS SYNTH_CAP_INPUT
#include "midi_synth.h"
static struct midi_operations pas_midi_operations =
{
{"Pro Audio Spectrum", 0, 0, SNDCARD_PAS},
&std_midi_synth,
{0},
pas_midi_open,
pas_midi_close,
pas_midi_ioctl,
pas_midi_out,
pas_midi_start_read,
pas_midi_end_read,
pas_midi_kick,
NULL,
pas_buffer_status,
NULL
};
void
pas_midi_init (void)
{
if (num_midis >= MAX_MIDI_DEV)
{
printk ("Sound: Too many midi devices detected\n");
return;
}
std_midi_synth.midi_dev = my_dev = num_midis;
midi_devs[num_midis++] = &pas_midi_operations;
}
void
pas_midi_interrupt (void)
{
unsigned char stat;
int i, incount;
unsigned long flags;
stat = pas_read (0x1B88);
if (stat & 0x04) /* Input data available */
{
incount = pas_read (0x1B89) & 0x0f; /* Input FIFO size */
if (!incount)
incount = 16;
for (i = 0; i < incount; i++)
if (input_opened)
{
midi_input_intr (my_dev, pas_read (0x178A));
}
else
pas_read (0x178A); /* Flush */
}
if (stat & (0x08 | 0x10))
{
save_flags (flags);
cli ();
while (qlen && dump_to_midi (tmp_queue[qhead]))
{
qlen--;
qhead++;
}
restore_flags (flags);
}
if (stat & 0x40)
{
printk ("MIDI output overrun %x,%x\n", pas_read (0x1B89), stat);
}
pas_write (stat, 0x1B88); /* Acknowledge interrupts */
}
#endif
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