usbmidi.c

linux 内核源代码

/*
 * usbmidi.c - ALSA USB MIDI driver
 *
 * Copyright (c) 2002-2007 Clemens Ladisch
 * All rights reserved.
 *
 * Based on the OSS usb-midi driver by NAGANO Daisuke,
 *          NetBSD's umidi driver by Takuya SHIOZAKI,
 *          the "USB Device Class Definition for MIDI Devices" by Roland
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed and/or modified 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 SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sound/driver.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/usb.h>
#include <sound/core.h>
#include <sound/rawmidi.h>
#include <sound/asequencer.h>
#include "usbaudio.h"


/*
 * define this to log all USB packets
 */
/* #define DUMP_PACKETS */

/*
 * how long to wait after some USB errors, so that khubd can disconnect() us
 * without too many spurious errors
 */
#define ERROR_DELAY_JIFFIES (HZ / 10)


MODULE_AUTHOR("Clemens Ladisch <[e-mail]>");
MODULE_DESCRIPTION("USB Audio/MIDI helper module");
MODULE_LICENSE("Dual BSD/GPL");


struct usb_ms_header_descriptor {
	__u8  bLength;
	__u8  bDescriptorType;
	__u8  bDescriptorSubtype;
	__u8  bcdMSC[2];
	__le16 wTotalLength;
} __attribute__ ((packed));

struct usb_ms_endpoint_descriptor {
	__u8  bLength;
	__u8  bDescriptorType;
	__u8  bDescriptorSubtype;
	__u8  bNumEmbMIDIJack;
	__u8  baAssocJackID[0];
} __attribute__ ((packed));

struct snd_usb_midi_in_endpoint;
struct snd_usb_midi_out_endpoint;
struct snd_usb_midi_endpoint;

struct usb_protocol_ops {
	void (*input)(struct snd_usb_midi_in_endpoint*, uint8_t*, int);
	void (*output)(struct snd_usb_midi_out_endpoint*);
	void (*output_packet)(struct urb*, uint8_t, uint8_t, uint8_t, uint8_t);
	void (*init_out_endpoint)(struct snd_usb_midi_out_endpoint*);
	void (*finish_out_endpoint)(struct snd_usb_midi_out_endpoint*);
};

struct snd_usb_midi {
	struct snd_usb_audio *chip;
	struct usb_interface *iface;
	const struct snd_usb_audio_quirk *quirk;
	struct snd_rawmidi *rmidi;
	struct usb_protocol_ops* usb_protocol_ops;
	struct list_head list;
	struct timer_list error_timer;

	struct snd_usb_midi_endpoint {
		struct snd_usb_midi_out_endpoint *out;
		struct snd_usb_midi_in_endpoint *in;
	} endpoints[MIDI_MAX_ENDPOINTS];
	unsigned long input_triggered;
};

struct snd_usb_midi_out_endpoint {
	struct snd_usb_midi* umidi;
	struct urb* urb;
	int urb_active;
	int max_transfer;		/* size of urb buffer */
	struct tasklet_struct tasklet;

	spinlock_t buffer_lock;

	struct usbmidi_out_port {
		struct snd_usb_midi_out_endpoint* ep;
		struct snd_rawmidi_substream *substream;
		int active;
		uint8_t cable;		/* cable number << 4 */
		uint8_t state;
#define STATE_UNKNOWN	0
#define STATE_1PARAM	1
#define STATE_2PARAM_1	2
#define STATE_2PARAM_2	3
#define STATE_SYSEX_0	4
#define STATE_SYSEX_1	5
#define STATE_SYSEX_2	6
		uint8_t data[2];
	} ports[0x10];
	int current_port;
};

struct snd_usb_midi_in_endpoint {
	struct snd_usb_midi* umidi;
	struct urb* urb;
	struct usbmidi_in_port {
		struct snd_rawmidi_substream *substream;
		u8 running_status_length;
	} ports[0x10];
	u8 seen_f5;
	u8 error_resubmit;
	int current_port;
};

static void snd_usbmidi_do_output(struct snd_usb_midi_out_endpoint* ep);

static const uint8_t snd_usbmidi_cin_length[] = {
	0, 0, 2, 3, 3, 1, 2, 3, 3, 3, 3, 3, 2, 2, 3, 1
};

/*
 * Submits the URB, with error handling.
 */
static int snd_usbmidi_submit_urb(struct urb* urb, gfp_t flags)
{
	int err = usb_submit_urb(urb, flags);
	if (err < 0 && err != -ENODEV)
		snd_printk(KERN_ERR "usb_submit_urb: %d\n", err);
	return err;
}

/*
 * Error handling for URB completion functions.
 */
static int snd_usbmidi_urb_error(int status)
{
	switch (status) {
	/* manually unlinked, or device gone */
	case -ENOENT:
	case -ECONNRESET:
	case -ESHUTDOWN:
	case -ENODEV:
		return -ENODEV;
	/* errors that might occur during unplugging */
	case -EPROTO:
	case -ETIME:
	case -EILSEQ:
		return -EIO;
	default:
		snd_printk(KERN_ERR "urb status %d\n", status);
		return 0; /* continue */
	}
}

/*
 * Receives a chunk of MIDI data.
 */
static void snd_usbmidi_input_data(struct snd_usb_midi_in_endpoint* ep, int portidx,
				   uint8_t* data, int length)
{
	struct usbmidi_in_port* port = &ep->ports[portidx];

	if (!port->substream) {
		snd_printd("unexpected port %d!\n", portidx);
		return;
	}
	if (!test_bit(port->substream->number, &ep->umidi->input_triggered))
		return;
	snd_rawmidi_receive(port->substream, data, length);
}

#ifdef DUMP_PACKETS
static void dump_urb(const char *type, const u8 *data, int length)
{
	snd_printk(KERN_DEBUG "%s packet: [", type);
	for (; length > 0; ++data, --length)
		printk(" %02x", *data);
	printk(" ]\n");
}
#else
#define dump_urb(type, data, length) /* nothing */
#endif

/*
 * Processes the data read from the device.
 */
static void snd_usbmidi_in_urb_complete(struct urb* urb)
{
	struct snd_usb_midi_in_endpoint* ep = urb->context;

	if (urb->status == 0) {
		dump_urb("received", urb->transfer_buffer, urb->actual_length);
		ep->umidi->usb_protocol_ops->input(ep, urb->transfer_buffer,
						   urb->actual_length);
	} else {
		int err = snd_usbmidi_urb_error(urb->status);
		if (err < 0) {
			if (err != -ENODEV) {
				ep->error_resubmit = 1;
				mod_timer(&ep->umidi->error_timer,
					  jiffies + ERROR_DELAY_JIFFIES);
			}
			return;
		}
	}

	urb->dev = ep->umidi->chip->dev;
	snd_usbmidi_submit_urb(urb, GFP_ATOMIC);
}

static void snd_usbmidi_out_urb_complete(struct urb* urb)
{
	struct snd_usb_midi_out_endpoint* ep = urb->context;

	spin_lock(&ep->buffer_lock);
	ep->urb_active = 0;
	spin_unlock(&ep->buffer_lock);
	if (urb->status < 0) {
		int err = snd_usbmidi_urb_error(urb->status);
		if (err < 0) {
			if (err != -ENODEV)
				mod_timer(&ep->umidi->error_timer,
					  jiffies + ERROR_DELAY_JIFFIES);
			return;
		}
	}
	snd_usbmidi_do_output(ep);
}

/*
 * This is called when some data should be transferred to the device
 * (from one or more substreams).
 */
static void snd_usbmidi_do_output(struct snd_usb_midi_out_endpoint* ep)
{
	struct urb* urb = ep->urb;
	unsigned long flags;

	spin_lock_irqsave(&ep->buffer_lock, flags);
	if (ep->urb_active || ep->umidi->chip->shutdown) {
		spin_unlock_irqrestore(&ep->buffer_lock, flags);
		return;
	}

	urb->transfer_buffer_length = 0;
	ep->umidi->usb_protocol_ops->output(ep);

	if (urb->transfer_buffer_length > 0) {
		dump_urb("sending", urb->transfer_buffer,
			 urb->transfer_buffer_length);
		urb->dev = ep->umidi->chip->dev;
		ep->urb_active = snd_usbmidi_submit_urb(urb, GFP_ATOMIC) >= 0;
	}
	spin_unlock_irqrestore(&ep->buffer_lock, flags);
}

static void snd_usbmidi_out_tasklet(unsigned long data)
{
	struct snd_usb_midi_out_endpoint* ep = (struct snd_usb_midi_out_endpoint *) data;

	snd_usbmidi_do_output(ep);
}

/* called after transfers had been interrupted due to some USB error */
static void snd_usbmidi_error_timer(unsigned long data)
{
	struct snd_usb_midi *umidi = (struct snd_usb_midi *)data;
	int i;

	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
		struct snd_usb_midi_in_endpoint *in = umidi->endpoints[i].in;
		if (in && in->error_resubmit) {
			in->error_resubmit = 0;
			in->urb->dev = umidi->chip->dev;
			snd_usbmidi_submit_urb(in->urb, GFP_ATOMIC);
		}
		if (umidi->endpoints[i].out)
			snd_usbmidi_do_output(umidi->endpoints[i].out);
	}
}

/* helper function to send static data that may not DMA-able */
static int send_bulk_static_data(struct snd_usb_midi_out_endpoint* ep,
				 const void *data, int len)
{
	int err;
	void *buf = kmemdup(data, len, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	dump_urb("sending", buf, len);
	err = usb_bulk_msg(ep->umidi->chip->dev, ep->urb->pipe, buf, len,
			   NULL, 250);
	kfree(buf);
	return err;
}

/*
 * Standard USB MIDI protocol: see the spec.
 * Midiman protocol: like the standard protocol, but the control byte is the
 * fourth byte in each packet, and uses length instead of CIN.
 */

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

	for (i = 0; i + 3 < buffer_length; i += 4)
		if (buffer[i] != 0) {
			int cable = buffer[i] >> 4;
			int length = snd_usbmidi_cin_length[buffer[i] & 0x0f];
			snd_usbmidi_input_data(ep, cable, &buffer[i + 1], length);
		}
}

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

	for (i = 0; i + 3 < buffer_length; i += 4)
		if (buffer[i + 3] != 0) {
			int port = buffer[i + 3] >> 4;
			int length = buffer[i + 3] & 3;
			snd_usbmidi_input_data(ep, port, &buffer[i], length);
		}
}

/*
 * Buggy M-Audio device: running status on input results in a packet that has
 * the data bytes but not the status byte and that is marked with CIN 4.
 */
static void snd_usbmidi_maudio_broken_running_status_input(
					struct snd_usb_midi_in_endpoint* ep,
					uint8_t* buffer, int buffer_length)
{
	int i;

	for (i = 0; i + 3 < buffer_length; i += 4)
		if (buffer[i] != 0) {
			int cable = buffer[i] >> 4;
			u8 cin = buffer[i] & 0x0f;
			struct usbmidi_in_port *port = &ep->ports[cable];
			int length;
			
			length = snd_usbmidi_cin_length[cin];
			if (cin == 0xf && buffer[i + 1] >= 0xf8)
				; /* realtime msg: no running status change */
			else if (cin >= 0x8 && cin <= 0xe)
				/* channel msg */
				port->running_status_length = length - 1;
			else if (cin == 0x4 &&
				 port->running_status_length != 0 &&
				 buffer[i + 1] < 0x80)
				/* CIN 4 that is not a SysEx */
				length = port->running_status_length;
			else
				/*
				 * All other msgs cannot begin running status.
				 * (A channel msg sent as two or three CIN 0xF
				 * packets could in theory, but this device
				 * doesn't use this format.)
				 */
				port->running_status_length = 0;
			snd_usbmidi_input_data(ep, cable, &buffer[i + 1], length);
		}
}

/*
 * CME protocol: like the standard protocol, but SysEx commands are sent as a
 * single USB packet preceded by a 0x0F byte.
 */
static void snd_usbmidi_cme_input(struct snd_usb_midi_in_endpoint *ep,
				  uint8_t *buffer, int buffer_length)
{
	if (buffer_length < 2 || (buffer[0] & 0x0f) != 0x0f)
		snd_usbmidi_standard_input(ep, buffer, buffer_length);
	else
		snd_usbmidi_input_data(ep, buffer[0] >> 4,
				       &buffer[1], buffer_length - 1);
}

/*
 * Adds one USB MIDI packet to the output buffer.
 */
static void snd_usbmidi_output_standard_packet(struct urb* urb, uint8_t p0,
					       uint8_t p1, uint8_t p2, uint8_t p3)
{

	uint8_t* buf = (uint8_t*)urb->transfer_buffer + urb->transfer_buffer_length;
	buf[0] = p0;
	buf[1] = p1;
	buf[2] = p2;
	buf[3] = p3;
	urb->transfer_buffer_length += 4;
}

/*
 * Adds one Midiman packet to the output buffer.
 */
static void snd_usbmidi_output_midiman_packet(struct urb* urb, uint8_t p0,
					      uint8_t p1, uint8_t p2, uint8_t p3)
{

	uint8_t* buf = (uint8_t*)urb->transfer_buffer + urb->transfer_buffer_length;