mpu401_uart.c

优龙2410linux2.6.8内核源代码

static int snd_mpu401_uart_output_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_OUTPUT, &mpu->mode);
	mpu->substream_output = NULL;
	if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode))
		snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);
	if (mpu->close_output)
		mpu->close_output(mpu);
	return 0;
}

/*
 * trigger input callback
 */
static void snd_mpu401_uart_input_trigger(snd_rawmidi_substream_t * substream, int up)
{
	unsigned long flags;
	mpu401_t *mpu;
	int max = 64;

	mpu = snd_magic_cast(mpu401_t, substream->rmidi->private_data, return);
	if (up) {
		if (! test_and_set_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode)) {
			/* first time - flush FIFO */
			while (max-- > 0)
				mpu->read(mpu, MPU401D(mpu));
			if (mpu->irq < 0)
				snd_mpu401_uart_add_timer(mpu, 1);
		}
		
		/* read data in advance */
		/* prevent double enter via rawmidi->event callback */
		if (atomic_dec_and_test(&mpu->rx_loop)) {
			local_irq_save(flags);
			if (spin_trylock(&mpu->input_lock)) {
				snd_mpu401_uart_input_read(mpu);
				spin_unlock(&mpu->input_lock);
			}
			local_irq_restore(flags);
		}
		atomic_inc(&mpu->rx_loop);
	} else {
		if (mpu->irq < 0)
			snd_mpu401_uart_remove_timer(mpu, 1);
		clear_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode);
	}
}

/*
 * transfer input pending data
 * call with input_lock spinlock held
 */
static void snd_mpu401_uart_input_read(mpu401_t * mpu)
{
	int max = 128;
	unsigned char byte;

	while (max-- > 0) {
		if (snd_mpu401_input_avail(mpu)) {
			byte = mpu->read(mpu, MPU401D(mpu));
			if (test_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode))
				snd_rawmidi_receive(mpu->substream_input, &byte, 1);
		} else {
			break; /* input not available */
		}
	}
}

/*
 *  Tx FIFO sizes:
 *    CS4237B			- 16 bytes
 *    AudioDrive ES1688         - 12 bytes
 *    S3 SonicVibes             -  8 bytes
 *    SoundBlaster AWE 64       -  2 bytes (ugly hardware)
 */

/*
 * write output pending bytes
 * call with output_lock spinlock held
 */
static void snd_mpu401_uart_output_write(mpu401_t * mpu)
{
	unsigned char byte;
	int max = 256, timeout;

	do {
		if (snd_rawmidi_transmit_peek(mpu->substream_output, &byte, 1) == 1) {
			for (timeout = 100; timeout > 0; timeout--) {
				if (snd_mpu401_output_ready(mpu)) {
					mpu->write(mpu, byte, MPU401D(mpu));
					snd_rawmidi_transmit_ack(mpu->substream_output, 1);
					break;
				}
			}
			if (timeout == 0)
				break;	/* Tx FIFO full - try again later */
		} else {
			snd_mpu401_uart_remove_timer (mpu, 0);
			break;	/* no other data - leave the tx loop */
		}
	} while (--max > 0);
}

/*
 * output trigger callback
 */
static void snd_mpu401_uart_output_trigger(snd_rawmidi_substream_t * substream, int up)
{
	unsigned long flags;
	mpu401_t *mpu;

	mpu = snd_magic_cast(mpu401_t, substream->rmidi->private_data, return);
	if (up) {
		set_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode);

		/* try to add the timer at each output trigger,
		 * since the output timer might have been removed in
		 * snd_mpu401_uart_output_write().
		 */
		snd_mpu401_uart_add_timer(mpu, 0);

		/* output pending data */
		/* prevent double enter via rawmidi->event callback */
		if (atomic_dec_and_test(&mpu->tx_loop)) {
			local_irq_save(flags);
			if (spin_trylock(&mpu->output_lock)) {
				snd_mpu401_uart_output_write(mpu);
				spin_unlock(&mpu->output_lock);
			}
			local_irq_restore(flags);
		}
		atomic_inc(&mpu->tx_loop);
	} else {
		snd_mpu401_uart_remove_timer(mpu, 0);
		clear_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode);
	}
}

/*

 */

static snd_rawmidi_ops_t snd_mpu401_uart_output =
{
	.open =		snd_mpu401_uart_output_open,
	.close =	snd_mpu401_uart_output_close,
	.trigger =	snd_mpu401_uart_output_trigger,
};

static snd_rawmidi_ops_t snd_mpu401_uart_input =
{
	.open =		snd_mpu401_uart_input_open,
	.close =	snd_mpu401_uart_input_close,
	.trigger =	snd_mpu401_uart_input_trigger,
};

static void snd_mpu401_uart_free(snd_rawmidi_t *rmidi)
{
	mpu401_t *mpu = snd_magic_cast(mpu401_t, rmidi->private_data, return);
	if (mpu->irq_flags && mpu->irq >= 0)
		free_irq(mpu->irq, (void *) mpu);
	if (mpu->res) {
		release_resource(mpu->res);
		kfree_nocheck(mpu->res);
	}
	snd_magic_kfree(mpu);
}

/**
 * snd_mpu401_uart_new - create an MPU401-UART instance
 * @card: the card instance
 * @device: the device index, zero-based
 * @hardware: the hardware type, MPU401_HW_XXXX
 * @port: the base address of MPU401 port
 * @integrated: non-zero if the port was already reserved by the chip
 * @irq: the irq number, -1 if no interrupt for mpu
 * @irq_flags: the irq request flags (SA_XXX), 0 if irq was already reserved.
 * @rrawmidi: the pointer to store the new rawmidi instance
 *
 * Creates a new MPU-401 instance.
 *
 * Note that the rawmidi instance is returned on the rrawmidi argument,
 * not the mpu401 instance itself.  To access to the mpu401 instance,
 * cast from rawmidi->private_data (with mpu401_t magic-cast).
 *
 * Returns zero if successful, or a negative error code.
 */
int snd_mpu401_uart_new(snd_card_t * card, int device,
			unsigned short hardware,
			unsigned long port, int integrated,
			int irq, int irq_flags,
			snd_rawmidi_t ** rrawmidi)
{
	mpu401_t *mpu;
	snd_rawmidi_t *rmidi;
	int err;

	if (rrawmidi)
		*rrawmidi = NULL;
	if ((err = snd_rawmidi_new(card, "MPU-401U", device, 1, 1, &rmidi)) < 0)
		return err;
	mpu = snd_magic_kcalloc(mpu401_t, 0, GFP_KERNEL);
	if (mpu == NULL) {
		snd_device_free(card, rmidi);
		return -ENOMEM;
	}
	rmidi->private_data = mpu;
	rmidi->private_free = snd_mpu401_uart_free;
	spin_lock_init(&mpu->input_lock);
	spin_lock_init(&mpu->output_lock);
	spin_lock_init(&mpu->timer_lock);
	mpu->hardware = hardware;
	if (!integrated) {
		int res_size = hardware == MPU401_HW_PC98II ? 4 : 2;
		if ((mpu->res = request_region(port, res_size, "MPU401 UART")) == NULL) {
			snd_printk(KERN_ERR "mpu401_uart: unable to grab port 0x%lx size %d\n", port, res_size);
			snd_device_free(card, rmidi);
			return -EBUSY;
		}
	}
	switch (hardware) {
	case MPU401_HW_AUREAL:
		mpu->write = mpu401_write_mmio;
		mpu->read = mpu401_read_mmio;
		break;
	default:
		mpu->write = mpu401_write_port;
		mpu->read = mpu401_read_port;
		break;
	}
	mpu->port = port;
	if (hardware == MPU401_HW_PC98II)
		mpu->cport = port + 2;
	else
		mpu->cport = port + 1;
	if (irq >= 0 && irq_flags) {
		if (request_irq(irq, snd_mpu401_uart_interrupt, irq_flags, "MPU401 UART", (void *) mpu)) {
			snd_printk(KERN_ERR "mpu401_uart: unable to grab IRQ %d\n", irq);
			snd_device_free(card, rmidi);
			return -EBUSY;
		}
	}
	mpu->irq = irq;
	mpu->irq_flags = irq_flags;
	if (card->shortname[0])
		snprintf(rmidi->name, sizeof(rmidi->name), "%s MIDI", card->shortname);
	else
		sprintf(rmidi->name, "MPU-401 MIDI %d-%d", card->number, device);
	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_mpu401_uart_output);
	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_mpu401_uart_input);
	rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT |
	                     SNDRV_RAWMIDI_INFO_INPUT |
	                     SNDRV_RAWMIDI_INFO_DUPLEX;
	mpu->rmidi = rmidi;
	if (rrawmidi)
		*rrawmidi = rmidi;
	return 0;
}

EXPORT_SYMBOL(snd_mpu401_uart_interrupt);
EXPORT_SYMBOL(snd_mpu401_uart_new);

/*
 *  INIT part
 */

static int __init alsa_mpu401_uart_init(void)
{
	return 0;
}

static void __exit alsa_mpu401_uart_exit(void)
{
}

module_init(alsa_mpu401_uart_init)
module_exit(alsa_mpu401_uart_exit)