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This driver/library can be used by the drivers for devices that provide MPU-401 (UART) compatible interface.
This file is part of Open Sound System.
Copyright (C) 4Front Technologies 1996-2008.
This this source file is released under GPL v2 license (no other versions). See the COPYING file included in the main directory of this source distribution for the license terms and conditions.
#include "oss_config.h"
#include "midi_core.h"
#include "uart401.h"
#define DATAPORT (devc->base)
#define COMDPORT (devc->base+1)
#define STATPORT (devc->base+1)
static int
uart401_status (uart401_devc * devc)
{
return INB (devc->osdev, STATPORT);
}
#define input_avail(devc) (!(uart401_status(devc)&INPUT_AVAIL))
#define output_ready(devc) (!(uart401_status(devc)&OUTPUT_READY))
static void
uart401_cmd (uart401_devc * devc, unsigned char cmd)
{
OUTB (devc->osdev, cmd, COMDPORT);
}
static int
uart401_read (uart401_devc * devc)
{
return INB (devc->osdev, DATAPORT);
}
static void
uart401_write (uart401_devc * devc, unsigned char byte)
{
OUTB (devc->osdev, byte, DATAPORT);
}
#define OUTPUT_READY 0x40
#define INPUT_AVAIL 0x80
#define MPU_ACK 0xFE
#define MPU_RESET 0xFF
#define UART_MODE_ON 0x3F
static int reset_uart401 (uart401_devc * devc);
static void enter_uart_mode (uart401_devc * devc);
static void
uart401_input_loop (uart401_devc * devc)
{
unsigned char buf[128];
int l = 0;
while (input_avail (devc))
{
int dev;
unsigned char c;
c = uart401_read (devc);
dev = devc->my_dev;
if (midi_devs[dev]->input_callback != NULL)
midi_devs[dev]->input_callback (dev, c);
if (c == MPU_ACK)
devc->input_byte = c;
else if ((devc->opened & OPEN_READ))
{
buf[l++] = c;
if (l >= sizeof (buf)) /* Buffer full */
{
if (devc->save_input_buffer != NULL)
devc->save_input_buffer (devc->my_dev, buf, l);
l = 0;
}
}
if (l > 0)
{
if (devc->save_input_buffer != NULL)
devc->save_input_buffer (devc->my_dev, buf, l);
}
}
}
void
uart401_irq (uart401_devc * devc)
{
if (devc->base == 0)
{
/* cmn_err(CE_CONT, "uart401_irq: Bad base address\n"); */
return;
}
if (input_avail (devc))
{
uart401_input_loop (devc);
}
}
/*ARGSUSED*/
static int
uart401_open (int dev, int mode, oss_midi_inputbyte_t inputbyte,
oss_midi_inputbuf_t inputbuf, oss_midi_outputintr_t outputintr)
{
uart401_devc *devc = (uart401_devc *) midi_devs[dev]->devc;
if (devc->opened)
{
return OSS_EBUSY;
}
while (input_avail (devc))
uart401_read (devc);
devc->save_input_buffer = inputbuf;
devc->opened = mode;
enter_uart_mode (devc);
devc->disabled = 0;
return 0;
}
/*ARGSUSED*/
static void
uart401_close (int dev, int mode)
{
uart401_devc *devc = (uart401_devc *) midi_devs[dev]->devc;
reset_uart401 (devc);
oss_udelay (10);
enter_uart_mode (devc);
reset_uart401 (devc);
devc->save_input_buffer = NULL;
devc->opened = 0;
}
static int
uart401_out (int dev, unsigned char midi_byte)
{
int timeout;
uart401_devc *devc = (uart401_devc *) midi_devs[dev]->devc;
oss_native_word flags;
if (devc->disabled)
return 1;
Test for input since pending input seems to block the output.
MUTEX_ENTER_IRQDISABLE (devc->mutex, flags);
if (input_avail (devc))
uart401_input_loop (devc);
MUTEX_EXIT_IRQRESTORE (devc->mutex, flags);
Sometimes it takes about 130000 loops before the output becomes ready (After reset). Normally it takes just about 10 loops.
for (timeout = 13000; timeout > 0 && !output_ready (devc); timeout--);
if (!output_ready (devc))
{
return 0;
}
uart401_write (devc, midi_byte);
return 1;
}
/*ARGSUSED*/
static int
uart401_ioctl (int dev, unsigned cmd, ioctl_arg arg)
{
return OSS_EINVAL;
}
static midi_driver_t uart401_driver = {
uart401_open,
uart401_close,
uart401_ioctl,
uart401_out
};
static void
enter_uart_mode (uart401_devc * devc)
{
int ok, timeout;
oss_native_word flags;
MUTEX_ENTER_IRQDISABLE (devc->mutex, flags);
for (timeout = 30000; timeout > 0 && !output_ready (devc); timeout--);
devc->input_byte = 0;
uart401_cmd (devc, UART_MODE_ON);
ok = 0;
for (timeout = 50000; timeout > 0 && !ok; timeout--)
if (devc->input_byte == MPU_ACK)
ok = 1;
else if (input_avail (devc))
if (uart401_read (devc) == MPU_ACK)
ok = 1;
MUTEX_EXIT_IRQRESTORE (devc->mutex, flags);
}
static int
reset_uart401 (uart401_devc * devc)
{
int ok, timeout, n;
oss_native_word flags;
Send the RESET command. Try again if no success at the first time.
MUTEX_ENTER_IRQDISABLE (devc->mutex, flags);
ok = 0;
for (n = 0; n < 2 && !ok; n++)
{
for (timeout = 30000; timeout > 0 && !output_ready (devc); timeout--);
devc->input_byte = 0;
uart401_cmd (devc, MPU_RESET);
Wait at least 25 msec. This method is not accurate so let's make the loop bit longer. Cannot sleep since this is called during boot.
for (timeout = 50000; timeout > 0 && !ok; timeout--)
if (devc->input_byte == MPU_ACK) /* Interrupt */
ok = 1;
else if (input_avail (devc))
if (uart401_read (devc) == MPU_ACK)
ok = 1;
}
if (ok)
Flush input before enabling interrupts
MUTEX_EXIT_IRQRESTORE (devc->mutex, flags);
return ok;
}
int
uart401_init (uart401_devc * devc, oss_device_t * osdev, int base, char *name)
{
int ok = 0;
DDB (cmn_err (CE_CONT, "Entered uart401_init(%x)\n", base));
devc->base = base;
devc->irq = 0;
devc->osdev = osdev;
MUTEX_INIT (devc->osdev, devc->mutex, MH_DRV + 3);
devc->running = 1;
devc->save_input_buffer = NULL;
devc->opened = 0;
devc->input_byte = 0;
devc->my_dev = 0;
devc->share_irq = 0;
ok = reset_uart401 (devc);
if (ok)
{
DDB (cmn_err (CE_CONT, "Reset UART401 OK\n"));
}
else
{
DDB (cmn_err
(CE_CONT, "Reset UART401 failed (no hardware present?).\n"));
DDB (cmn_err (CE_CONT, "mpu401 status %02x\n", uart401_status (devc)));
}
if (!ok)
{
return 0;
}
DDB (cmn_err (CE_CONT, "uart401 detected OK\n"));
enter_uart_mode (devc);
devc->my_dev = oss_install_mididev (OSS_MIDI_DRIVER_VERSION, "UART401", name, &uart401_driver, sizeof (midi_driver_t),
0, devc, devc->osdev);
devc->opened = 0;
#ifdef USE_POLLING
if (!timer_armed)
{
timer_armed = 1;
poll_interval = OSS_HZ / 10;
if (poll_interval < 1)
poll_interval = 1;
INIT_TIMER (uart401_timer, uart401_poll);
ACTIVATE_TIMER (uart401_timer, uart401_poll, poll_interval);
}
#endif
return 1;
}
void
uart401_disable (uart401_devc * devc)
{
#ifdef USE_POLLING
if (timer_armed)
{
timer_armed = 0;
REMOVE_TIMER (uart401_timer, uart401_poll);
}
else;
#endif
if (!devc->running)
return;
reset_uart401 (devc);
devc->running = 0;
}