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/* midi.c
*
* Milkymist MIDI driver for RTEMS
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* COPYRIGHT (c) 2010, 2011 Sebastien Bourdeauducq
*/
#define RTEMS_STATUS_CHECKS_USE_PRINTK
#include <stdlib.h>
#include <sys/types.h>
#include <rtems.h>
#include <rtems/status-checks.h>
#include <bsp.h>
#include <bsp/irq-generic.h>
#include <rtems/libio.h>
#include "../include/system_conf.h"
#include "milkymist_midi.h"
#define DEVICE_NAME "/dev/midi"
static rtems_id midi_q;
static unsigned char *midi_p = NULL;
static unsigned char midi_msg[3];
static rtems_isr interrupt_handler(rtems_vector_number n)
{
unsigned char msg;
while (MM_READ(MM_MIDI_STAT) & MIDI_STAT_RX_EVT) {
msg = MM_READ(MM_MIDI_RXTX);
MM_WRITE(MM_MIDI_STAT, MIDI_STAT_RX_EVT);
if ((msg & 0xf8) == 0xf8)
continue; /* ignore system real-time */
if (msg & 0x80)
midi_p = midi_msg; /* status byte */
if (!midi_p)
continue; /* ignore extra or unsynchronized data */
*midi_p++ = msg;
if (midi_p == midi_msg+3) {
/* received a complete MIDI message */
rtems_message_queue_send(midi_q, midi_msg, 3);
midi_p = NULL;
}
}
lm32_interrupt_ack(1 << MM_IRQ_MIDI);
}
rtems_device_driver midi_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *arg
)
{
rtems_status_code sc;
rtems_isr_entry dummy;
sc = rtems_io_register_name(DEVICE_NAME, major, 0);
RTEMS_CHECK_SC(sc, "create MIDI input device");
sc = rtems_message_queue_create(
rtems_build_name('M', 'I', 'D', 'I'),
32,
3,
0,
&midi_q
);
RTEMS_CHECK_SC(sc, "create MIDI queue");
rtems_interrupt_catch(interrupt_handler, MM_IRQ_MIDI, &dummy);
bsp_interrupt_vector_enable(MM_IRQ_MIDI);
/* Only MIDI THRU mode is supported atm */
MM_WRITE(MM_MIDI_CTRL, MIDI_CTRL_RX_INT|MIDI_CTRL_THRU);
return RTEMS_SUCCESSFUL;
}
rtems_device_driver midi_open(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *arg
)
{
uint32_t count;
rtems_message_queue_flush(midi_q, &count);
return RTEMS_SUCCESSFUL;
}
rtems_device_driver midi_read(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *arg
)
{
rtems_libio_rw_args_t *rw_args = (rtems_libio_rw_args_t *)arg;
rtems_status_code sc;
sc = rtems_message_queue_receive(
midi_q,
rw_args->buffer,
(size_t *)&rw_args->bytes_moved,
RTEMS_WAIT,
RTEMS_NO_TIMEOUT
);
if(sc == RTEMS_SUCCESSFUL)
return RTEMS_SUCCESSFUL;
else {
rw_args->bytes_moved = 0;
return RTEMS_UNSATISFIED;
}
}
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