mpu401_uart.c

优龙2410linux2.6.8内核源代码

/*
 *  Copyright (c) by Jaroslav Kysela <[e-mail]>
 *  Routines for control of MPU-401 in UART mode
 *
 *  MPU-401 supports UART mode which is not capable generate transmit
 *  interrupts thus output is done via polling. Also, if irq < 0, then
 *  input is done also via polling. Do not expect good performance.
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 *   13-03-2003:
 *      Added support for different kind of hardware I/O. Build in choices
 *      are port and mmio. For other kind of I/O, set mpu->read and
 *      mpu->write to your own I/O functions.
 *
 */

#include <sound/driver.h>
#include <asm/io.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <sound/core.h>
#include <sound/mpu401.h>

MODULE_AUTHOR("Jaroslav Kysela <[e-mail]>");
MODULE_DESCRIPTION("Routines for control of MPU-401 in UART mode");
MODULE_LICENSE("GPL");

static void snd_mpu401_uart_input_read(mpu401_t * mpu);
static void snd_mpu401_uart_output_write(mpu401_t * mpu);

/*

 */

#define snd_mpu401_input_avail(mpu)	(!(mpu->read(mpu, MPU401C(mpu)) & 0x80))
#define snd_mpu401_output_ready(mpu)	(!(mpu->read(mpu, MPU401C(mpu)) & 0x40))

#define MPU401_RESET		0xff
#define MPU401_ENTER_UART	0x3f
#define MPU401_ACK		0xfe

/* Build in lowlevel io */
static void mpu401_write_port(mpu401_t *mpu, unsigned char data, unsigned long addr)
{
	outb(data, addr);
}

static unsigned char mpu401_read_port(mpu401_t *mpu, unsigned long addr)
{
	return inb(addr);
}

static void mpu401_write_mmio(mpu401_t *mpu, unsigned char data, unsigned long addr)
{
	writeb(data, (unsigned long*)addr);
}

static unsigned char mpu401_read_mmio(mpu401_t *mpu, unsigned long addr)
{
	return readb((unsigned long*)addr);
}
/*  */

static void snd_mpu401_uart_clear_rx(mpu401_t *mpu)
{
	int timeout = 100000;
	for (; timeout > 0 && snd_mpu401_input_avail(mpu); timeout--)
		mpu->read(mpu, MPU401D(mpu));
#ifdef CONFIG_SND_DEBUG
	if (timeout <= 0)
		snd_printk("cmd: clear rx timeout (status = 0x%x)\n", mpu->read(mpu, MPU401C(mpu)));
#endif
}

static void _snd_mpu401_uart_interrupt(mpu401_t *mpu)
{
	spin_lock(&mpu->input_lock);
	if (test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode)) {
		atomic_dec(&mpu->rx_loop);
		snd_mpu401_uart_input_read(mpu);
		atomic_inc(&mpu->rx_loop);
	} else {
		snd_mpu401_uart_clear_rx(mpu);
	}
	spin_unlock(&mpu->input_lock);
 	/* ok. for better Tx performance try do some output when input is done */
	if (test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode) &&
	    test_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode)) {
		if (spin_trylock(&mpu->output_lock)) {
			atomic_dec(&mpu->tx_loop);
			snd_mpu401_uart_output_write(mpu);
			atomic_inc(&mpu->tx_loop);
			spin_unlock(&mpu->output_lock);
		}
	}
}

/**
 * snd_mpu401_uart_interrupt - generic MPU401-UART interrupt handler
 * @irq: the irq number
 * @dev_id: mpu401 instance
 * @regs: the reigster
 *
 * Processes the interrupt for MPU401-UART i/o.
 */
irqreturn_t snd_mpu401_uart_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	mpu401_t *mpu = snd_magic_cast(mpu401_t, dev_id, return IRQ_NONE);
	
	if (mpu == NULL)
		return IRQ_NONE;
	_snd_mpu401_uart_interrupt(mpu);
	return IRQ_HANDLED;
}

/*
 * timer callback
 * reprogram the timer and call the interrupt job
 */
static void snd_mpu401_uart_timer(unsigned long data)
{
	mpu401_t *mpu = snd_magic_cast(mpu401_t, (void *)data, return);

	spin_lock(&mpu->timer_lock);
	/*mpu->mode |= MPU401_MODE_TIMER;*/
	mpu->timer.expires = 1 + jiffies;
	add_timer(&mpu->timer);
	spin_unlock(&mpu->timer_lock);
	if (mpu->rmidi)
		_snd_mpu401_uart_interrupt(mpu);
}

/*
 * initialize the timer callback if not programmed yet
 */
static void snd_mpu401_uart_add_timer (mpu401_t *mpu, int input)
{
	unsigned long flags;

	spin_lock_irqsave (&mpu->timer_lock, flags);
	if (mpu->timer_invoked == 0) {
		init_timer(&mpu->timer);
		mpu->timer.data = (unsigned long)mpu;
		mpu->timer.function = snd_mpu401_uart_timer;
		mpu->timer.expires = 1 + jiffies;
		add_timer(&mpu->timer);
	} 
	mpu->timer_invoked |= input ? MPU401_MODE_INPUT_TIMER : MPU401_MODE_OUTPUT_TIMER;
	spin_unlock_irqrestore (&mpu->timer_lock, flags);
}

/*
 * remove the timer callback if still active
 */
static void snd_mpu401_uart_remove_timer (mpu401_t *mpu, int input)
{
	unsigned long flags;

	spin_lock_irqsave (&mpu->timer_lock, flags);
	if (mpu->timer_invoked) {
		mpu->timer_invoked &= input ? ~MPU401_MODE_INPUT_TIMER : ~MPU401_MODE_OUTPUT_TIMER;
		if (! mpu->timer_invoked)
			del_timer(&mpu->timer);
	}
	spin_unlock_irqrestore (&mpu->timer_lock, flags);
}

/*

 */

static void snd_mpu401_uart_cmd(mpu401_t * mpu, unsigned char cmd, int ack)
{
	unsigned long flags;
	int timeout, ok;

	spin_lock_irqsave(&mpu->input_lock, flags);
	if (mpu->hardware != MPU401_HW_TRID4DWAVE) {
		mpu->write(mpu, 0x00, MPU401D(mpu));
		/*snd_mpu401_uart_clear_rx(mpu);*/
	}
	/* ok. standard MPU-401 initialization */
	if (mpu->hardware != MPU401_HW_SB) {
		for (timeout = 1000; timeout > 0 && !snd_mpu401_output_ready(mpu); timeout--)
			udelay(10);
#ifdef CONFIG_SND_DEBUG
		if (!timeout)
			snd_printk("cmd: tx timeout (status = 0x%x)\n", mpu->read(mpu, MPU401C(mpu)));
#endif
	}
	mpu->write(mpu, cmd, MPU401C(mpu));
	if (ack) {
		ok = 0;
		timeout = 10000;
		while (!ok && timeout-- > 0) {
			if (snd_mpu401_input_avail(mpu)) {
				if (mpu->read(mpu, MPU401D(mpu)) == MPU401_ACK)
					ok = 1;
			}
		}
		if (!ok && mpu->read(mpu, MPU401D(mpu)) == MPU401_ACK)
			ok = 1;
	} else {
		ok = 1;
	}
	spin_unlock_irqrestore(&mpu->input_lock, flags);
	if (! ok)
		snd_printk("cmd: 0x%x failed at 0x%lx (status = 0x%x, data = 0x%x)\n", cmd, mpu->port, mpu->read(mpu, MPU401C(mpu)), mpu->read(mpu, MPU401D(mpu)));
	// snd_printk("cmd: 0x%x at 0x%lx (status = 0x%x, data = 0x%x)\n", cmd, mpu->port, mpu->read(mpu, MPU401C(mpu)), mpu->read(mpu, MPU401D(mpu)));
}

/*
 * input/output open/close - protected by open_mutex in rawmidi.c
 */
static int snd_mpu401_uart_input_open(snd_rawmidi_substream_t * substream)
{
	mpu401_t *mpu;
	int err;

	mpu = snd_magic_cast(mpu401_t, substream->rmidi->private_data, return -ENXIO);
	if (mpu->open_input && (err = mpu->open_input(mpu)) < 0)
		return err;
	if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode)) {
		snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1);
		snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1);
	}
	mpu->substream_input = substream;
	atomic_set(&mpu->rx_loop, 1);
	set_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);
	return 0;
}

static int snd_mpu401_uart_output_open(snd_rawmidi_substream_t * substream)
{
	mpu401_t *mpu;
	int err;

	mpu = snd_magic_cast(mpu401_t, substream->rmidi->private_data, return -ENXIO);
	if (mpu->open_output && (err = mpu->open_output(mpu)) < 0)
		return err;
	if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode)) {
		snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1);
		snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 1);
	}
	mpu->substream_output = substream;
	atomic_set(&mpu->tx_loop, 1);
	set_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode);
	return 0;
}

static int snd_mpu401_uart_input_close(snd_rawmidi_substream_t * substream)
{
	mpu401_t *mpu;

	mpu = snd_magic_cast(mpu401_t, substream->rmidi->private_data, return -ENXIO);
	clear_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);
	mpu->substream_input = NULL;
	if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode))
		snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);
	if (mpu->close_input)
		mpu->close_input(mpu);
	return 0;
}