usbmidi.c

linux 内核源代码

	buf[0] = p1;
	buf[1] = p2;
	buf[2] = p3;
	buf[3] = (p0 & 0xf0) | snd_usbmidi_cin_length[p0 & 0x0f];
	urb->transfer_buffer_length += 4;
}

/*
 * Converts MIDI commands to USB MIDI packets.
 */
static void snd_usbmidi_transmit_byte(struct usbmidi_out_port* port,
				      uint8_t b, struct urb* urb)
{
	uint8_t p0 = port->cable;
	void (*output_packet)(struct urb*, uint8_t, uint8_t, uint8_t, uint8_t) =
		port->ep->umidi->usb_protocol_ops->output_packet;

	if (b >= 0xf8) {
		output_packet(urb, p0 | 0x0f, b, 0, 0);
	} else if (b >= 0xf0) {
		switch (b) {
		case 0xf0:
			port->data[0] = b;
			port->state = STATE_SYSEX_1;
			break;
		case 0xf1:
		case 0xf3:
			port->data[0] = b;
			port->state = STATE_1PARAM;
			break;
		case 0xf2:
			port->data[0] = b;
			port->state = STATE_2PARAM_1;
			break;
		case 0xf4:
		case 0xf5:
			port->state = STATE_UNKNOWN;
			break;
		case 0xf6:
			output_packet(urb, p0 | 0x05, 0xf6, 0, 0);
			port->state = STATE_UNKNOWN;
			break;
		case 0xf7:
			switch (port->state) {
			case STATE_SYSEX_0:
				output_packet(urb, p0 | 0x05, 0xf7, 0, 0);
				break;
			case STATE_SYSEX_1:
				output_packet(urb, p0 | 0x06, port->data[0], 0xf7, 0);
				break;
			case STATE_SYSEX_2:
				output_packet(urb, p0 | 0x07, port->data[0], port->data[1], 0xf7);
				break;
			}
			port->state = STATE_UNKNOWN;
			break;
		}
	} else if (b >= 0x80) {
		port->data[0] = b;
		if (b >= 0xc0 && b <= 0xdf)
			port->state = STATE_1PARAM;
		else
			port->state = STATE_2PARAM_1;
	} else { /* b < 0x80 */
		switch (port->state) {
		case STATE_1PARAM:
			if (port->data[0] < 0xf0) {
				p0 |= port->data[0] >> 4;
			} else {
				p0 |= 0x02;
				port->state = STATE_UNKNOWN;
			}
			output_packet(urb, p0, port->data[0], b, 0);
			break;
		case STATE_2PARAM_1:
			port->data[1] = b;
			port->state = STATE_2PARAM_2;
			break;
		case STATE_2PARAM_2:
			if (port->data[0] < 0xf0) {
				p0 |= port->data[0] >> 4;
				port->state = STATE_2PARAM_1;
			} else {
				p0 |= 0x03;
				port->state = STATE_UNKNOWN;
			}
			output_packet(urb, p0, port->data[0], port->data[1], b);
			break;
		case STATE_SYSEX_0:
			port->data[0] = b;
			port->state = STATE_SYSEX_1;
			break;
		case STATE_SYSEX_1:
			port->data[1] = b;
			port->state = STATE_SYSEX_2;
			break;
		case STATE_SYSEX_2:
			output_packet(urb, p0 | 0x04, port->data[0], port->data[1], b);
			port->state = STATE_SYSEX_0;
			break;
		}
	}
}

static void snd_usbmidi_standard_output(struct snd_usb_midi_out_endpoint* ep)
{
	struct urb* urb = ep->urb;
	int p;

	/* FIXME: lower-numbered ports can starve higher-numbered ports */
	for (p = 0; p < 0x10; ++p) {
		struct usbmidi_out_port* port = &ep->ports[p];
		if (!port->active)
			continue;
		while (urb->transfer_buffer_length + 3 < ep->max_transfer) {
			uint8_t b;
			if (snd_rawmidi_transmit(port->substream, &b, 1) != 1) {
				port->active = 0;
				break;
			}
			snd_usbmidi_transmit_byte(port, b, urb);
		}
	}
}

static struct usb_protocol_ops snd_usbmidi_standard_ops = {
	.input = snd_usbmidi_standard_input,
	.output = snd_usbmidi_standard_output,
	.output_packet = snd_usbmidi_output_standard_packet,
};

static struct usb_protocol_ops snd_usbmidi_midiman_ops = {
	.input = snd_usbmidi_midiman_input,
	.output = snd_usbmidi_standard_output, 
	.output_packet = snd_usbmidi_output_midiman_packet,
};

static struct usb_protocol_ops snd_usbmidi_maudio_broken_running_status_ops = {
	.input = snd_usbmidi_maudio_broken_running_status_input,
	.output = snd_usbmidi_standard_output, 
	.output_packet = snd_usbmidi_output_standard_packet,
};

static struct usb_protocol_ops snd_usbmidi_cme_ops = {
	.input = snd_usbmidi_cme_input,
	.output = snd_usbmidi_standard_output,
	.output_packet = snd_usbmidi_output_standard_packet,
};

/*
 * Novation USB MIDI protocol: number of data bytes is in the first byte
 * (when receiving) (+1!) or in the second byte (when sending); data begins
 * at the third byte.
 */

static void snd_usbmidi_novation_input(struct snd_usb_midi_in_endpoint* ep,
				       uint8_t* buffer, int buffer_length)
{
	if (buffer_length < 2 || !buffer[0] || buffer_length < buffer[0] + 1)
		return;
	snd_usbmidi_input_data(ep, 0, &buffer[2], buffer[0] - 1);
}

static void snd_usbmidi_novation_output(struct snd_usb_midi_out_endpoint* ep)
{
	uint8_t* transfer_buffer;
	int count;

	if (!ep->ports[0].active)
		return;
	transfer_buffer = ep->urb->transfer_buffer;
	count = snd_rawmidi_transmit(ep->ports[0].substream,
				     &transfer_buffer[2],
				     ep->max_transfer - 2);
	if (count < 1) {
		ep->ports[0].active = 0;
		return;
	}
	transfer_buffer[0] = 0;
	transfer_buffer[1] = count;
	ep->urb->transfer_buffer_length = 2 + count;
}

static struct usb_protocol_ops snd_usbmidi_novation_ops = {
	.input = snd_usbmidi_novation_input,
	.output = snd_usbmidi_novation_output,
};

/*
 * "raw" protocol: used by the MOTU FastLane.
 */

static void snd_usbmidi_raw_input(struct snd_usb_midi_in_endpoint* ep,
				  uint8_t* buffer, int buffer_length)
{
	snd_usbmidi_input_data(ep, 0, buffer, buffer_length);
}

static void snd_usbmidi_raw_output(struct snd_usb_midi_out_endpoint* ep)
{
	int count;

	if (!ep->ports[0].active)
		return;
	count = snd_rawmidi_transmit(ep->ports[0].substream,
				     ep->urb->transfer_buffer,
				     ep->max_transfer);
	if (count < 1) {
		ep->ports[0].active = 0;
		return;
	}
	ep->urb->transfer_buffer_length = count;
}

static struct usb_protocol_ops snd_usbmidi_raw_ops = {
	.input = snd_usbmidi_raw_input,
	.output = snd_usbmidi_raw_output,
};

/*
 * Emagic USB MIDI protocol: raw MIDI with "F5 xx" port switching.
 */

static void snd_usbmidi_emagic_init_out(struct snd_usb_midi_out_endpoint* ep)
{
	static const u8 init_data[] = {
		/* initialization magic: "get version" */
		0xf0,
		0x00, 0x20, 0x31,	/* Emagic */
		0x64,			/* Unitor8 */
		0x0b,			/* version number request */
		0x00,			/* command version */
		0x00,			/* EEPROM, box 0 */
		0xf7
	};
	send_bulk_static_data(ep, init_data, sizeof(init_data));
	/* while we're at it, pour on more magic */
	send_bulk_static_data(ep, init_data, sizeof(init_data));
}

static void snd_usbmidi_emagic_finish_out(struct snd_usb_midi_out_endpoint* ep)
{
	static const u8 finish_data[] = {
		/* switch to patch mode with last preset */
		0xf0,
		0x00, 0x20, 0x31,	/* Emagic */
		0x64,			/* Unitor8 */
		0x10,			/* patch switch command */
		0x00,			/* command version */
		0x7f,			/* to all boxes */
		0x40,			/* last preset in EEPROM */
		0xf7
	};
	send_bulk_static_data(ep, finish_data, sizeof(finish_data));
}

static void snd_usbmidi_emagic_input(struct snd_usb_midi_in_endpoint* ep,
				     uint8_t* buffer, int buffer_length)
{
	int i;

	/* FF indicates end of valid data */
	for (i = 0; i < buffer_length; ++i)
		if (buffer[i] == 0xff) {
			buffer_length = i;
			break;
		}

	/* handle F5 at end of last buffer */
	if (ep->seen_f5)
		goto switch_port;

	while (buffer_length > 0) {
		/* determine size of data until next F5 */
		for (i = 0; i < buffer_length; ++i)
			if (buffer[i] == 0xf5)
				break;
		snd_usbmidi_input_data(ep, ep->current_port, buffer, i);
		buffer += i;
		buffer_length -= i;

		if (buffer_length <= 0)
			break;
		/* assert(buffer[0] == 0xf5); */
		ep->seen_f5 = 1;
		++buffer;
		--buffer_length;

	switch_port:
		if (buffer_length <= 0)
			break;
		if (buffer[0] < 0x80) {
			ep->current_port = (buffer[0] - 1) & 15;
			++buffer;
			--buffer_length;
		}
		ep->seen_f5 = 0;
	}
}

static void snd_usbmidi_emagic_output(struct snd_usb_midi_out_endpoint* ep)
{
	int port0 = ep->current_port;
	uint8_t* buf = ep->urb->transfer_buffer;
	int buf_free = ep->max_transfer;
	int length, i;

	for (i = 0; i < 0x10; ++i) {
		/* round-robin, starting at the last current port */
		int portnum = (port0 + i) & 15;
		struct usbmidi_out_port* port = &ep->ports[portnum];

		if (!port->active)
			continue;
		if (snd_rawmidi_transmit_peek(port->substream, buf, 1) != 1) {
			port->active = 0;
			continue;
		}

		if (portnum != ep->current_port) {
			if (buf_free < 2)
				break;
			ep->current_port = portnum;
			buf[0] = 0xf5;
			buf[1] = (portnum + 1) & 15;
			buf += 2;
			buf_free -= 2;
		}

		if (buf_free < 1)
			break;
		length = snd_rawmidi_transmit(port->substream, buf, buf_free);
		if (length > 0) {
			buf += length;
			buf_free -= length;
			if (buf_free < 1)
				break;
		}
	}
	if (buf_free < ep->max_transfer && buf_free > 0) {
		*buf = 0xff;
		--buf_free;
	}
	ep->urb->transfer_buffer_length = ep->max_transfer - buf_free;
}

static struct usb_protocol_ops snd_usbmidi_emagic_ops = {
	.input = snd_usbmidi_emagic_input,
	.output = snd_usbmidi_emagic_output,
	.init_out_endpoint = snd_usbmidi_emagic_init_out,
	.finish_out_endpoint = snd_usbmidi_emagic_finish_out,
};


static int snd_usbmidi_output_open(struct snd_rawmidi_substream *substream)
{
	struct snd_usb_midi* umidi = substream->rmidi->private_data;
	struct usbmidi_out_port* port = NULL;
	int i, j;

	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i)
		if (umidi->endpoints[i].out)
			for (j = 0; j < 0x10; ++j)
				if (umidi->endpoints[i].out->ports[j].substream == substream) {
					port = &umidi->endpoints[i].out->ports[j];
					break;
				}
	if (!port) {
		snd_BUG();
		return -ENXIO;
	}
	substream->runtime->private_data = port;
	port->state = STATE_UNKNOWN;
	return 0;
}

static int snd_usbmidi_output_close(struct snd_rawmidi_substream *substream)
{
	return 0;
}

static void snd_usbmidi_output_trigger(struct snd_rawmidi_substream *substream, int up)
{
	struct usbmidi_out_port* port = (struct usbmidi_out_port*)substream->runtime->private_data;

	port->active = up;
	if (up) {
		if (port->ep->umidi->chip->shutdown) {
			/* gobble up remaining bytes to prevent wait in
			 * snd_rawmidi_drain_output */
			while (!snd_rawmidi_transmit_empty(substream))
				snd_rawmidi_transmit_ack(substream, 1);
			return;
		}
		tasklet_hi_schedule(&port->ep->tasklet);
	}
}

static int snd_usbmidi_input_open(struct snd_rawmidi_substream *substream)
{
	return 0;
}

static int snd_usbmidi_input_close(struct snd_rawmidi_substream *substream)
{
	return 0;
}

static void snd_usbmidi_input_trigger(struct snd_rawmidi_substream *substream, int up)
{
	struct snd_usb_midi* umidi = substream->rmidi->private_data;

	if (up)
		set_bit(substream->number, &umidi->input_triggered);
	else
		clear_bit(substream->number, &umidi->input_triggered);
}

static struct snd_rawmidi_ops snd_usbmidi_output_ops = {
	.open = snd_usbmidi_output_open,
	.close = snd_usbmidi_output_close,
	.trigger = snd_usbmidi_output_trigger,
};

static struct snd_rawmidi_ops snd_usbmidi_input_ops = {
	.open = snd_usbmidi_input_open,
	.close = snd_usbmidi_input_close,
	.trigger = snd_usbmidi_input_trigger
};

/*
 * Frees an input endpoint.
 * May be called when ep hasn't been initialized completely.
 */
static void snd_usbmidi_in_endpoint_delete(struct snd_usb_midi_in_endpoint* ep)
{
	if (ep->urb) {
		usb_buffer_free(ep->umidi->chip->dev,
				ep->urb->transfer_buffer_length,
				ep->urb->transfer_buffer,
				ep->urb->transfer_dma);
		usb_free_urb(ep->urb);
	}
	kfree(ep);
}