bluetooth.c

讲述linux的初始化过程

	if (!count) {
		dbg(__FUNCTION__ " - zero length read bulk");
		goto exit;
	}

#ifdef DEBUG
	if (count) {
		printk (KERN_DEBUG __FILE__ ": " __FUNCTION__ "- length = %d, data = ", count);
		for (i = 0; i < count; ++i) {
			printk ("%.2x ", data[i]);
		}
		printk ("\n");
	}
#endif
	/* We add  a packet type identifier to the beginning of each
	   HCI frame.  This makes the data in the tty look like a
	   serial USB devices.  Each HCI frame can be broken across
	   multiple URBs so we buffer them until we have a full hci
	   packet */
	
	if (!bluetooth->bulk_packet_pos) {
		bluetooth->bulk_buffer[0] = ACL_PKT;
		bluetooth->bulk_packet_pos++;
	}

	if (bluetooth->bulk_packet_pos + count > ACL_BUFFER_SIZE) {
		err(__FUNCTION__ " - exceeded ACL_BUFFER_SIZE");
		bluetooth->bulk_packet_pos = 0;
		goto exit;
	}

	memcpy (&bluetooth->bulk_buffer[bluetooth->bulk_packet_pos],
		urb->transfer_buffer, count);
	bluetooth->bulk_packet_pos += count;
	urb->actual_length = 0;

	if (bluetooth->bulk_packet_pos >= ACL_HDR_SIZE) {
		packet_size = CHAR2INT16(bluetooth->bulk_buffer[4],bluetooth->bulk_buffer[3]);
	} else {
		goto exit;
	}

	if (packet_size + ACL_HDR_SIZE < bluetooth->bulk_packet_pos) {
		err(__FUNCTION__ " - packet was too long");
		bluetooth->bulk_packet_pos = 0;
		goto exit;
	}

	if (packet_size + ACL_HDR_SIZE == bluetooth->bulk_packet_pos) {
		for (i = 0; i < bluetooth->bulk_packet_pos; ++i) {
			/* if we insert more than TTY_FLIPBUF_SIZE characters, we drop them. */
			if (bluetooth->tty->flip.count >= TTY_FLIPBUF_SIZE) {
				tty_flip_buffer_push(bluetooth->tty);
			}
			tty_insert_flip_char(bluetooth->tty, bluetooth->bulk_buffer[i], 0);
		}
		tty_flip_buffer_push(bluetooth->tty);
		bluetooth->bulk_packet_pos = 0;
	}	

exit:
	FILL_BULK_URB(bluetooth->read_urb, bluetooth->dev, 
		      usb_rcvbulkpipe(bluetooth->dev, bluetooth->bulk_in_endpointAddress),
		      bluetooth->bulk_in_buffer, bluetooth->bulk_in_buffer_size, 
		      bluetooth_read_bulk_callback, bluetooth);
	result = usb_submit_urb(bluetooth->read_urb);
	if (result)
		err (__FUNCTION__ " - failed resubmitting read urb, error %d", result);

	return;
}


static void bluetooth_write_bulk_callback (struct urb *urb)
{
	struct usb_bluetooth *bluetooth = get_usb_bluetooth ((struct usb_bluetooth *)urb->context, __FUNCTION__);

	dbg(__FUNCTION__);

	if (!bluetooth) {
		dbg(__FUNCTION__ " - bad bluetooth pointer, exiting");
		return;
	}

	if (urb->status) {
		dbg(__FUNCTION__ " - nonzero write bulk status received: %d", urb->status);
		return;
	}

	/* wake up our little function to let the tty layer know that something happened */
	queue_task(&bluetooth->tqueue, &tq_immediate);
	mark_bh(IMMEDIATE_BH);
	return;
}


static void bluetooth_softint(void *private)
{
	struct usb_bluetooth *bluetooth = get_usb_bluetooth ((struct usb_bluetooth *)private, __FUNCTION__);
	struct tty_struct *tty;

	dbg(__FUNCTION__);

	if (!bluetooth) {
		return;
	}

	tty = bluetooth->tty;
	if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) && tty->ldisc.write_wakeup) {
		dbg(__FUNCTION__ " - write wakeup call.");
		(tty->ldisc.write_wakeup)(tty);
	}

	wake_up_interruptible(&tty->write_wait);
}


static void * usb_bluetooth_probe(struct usb_device *dev, unsigned int ifnum,
			 	  const struct usb_device_id *id)
{
	struct usb_bluetooth *bluetooth = NULL;
	struct usb_interface_descriptor *interface;
	struct usb_endpoint_descriptor *endpoint;
	struct usb_endpoint_descriptor *interrupt_in_endpoint[8];
	struct usb_endpoint_descriptor *bulk_in_endpoint[8];
	struct usb_endpoint_descriptor *bulk_out_endpoint[8];
	int control_out_endpoint;

	int minor;
	int buffer_size;
	int i;
	int num_interrupt_in = 0;
	int num_bulk_in = 0;
	int num_bulk_out = 0;

	interface = &dev->actconfig->interface[ifnum].altsetting[0];
	control_out_endpoint = interface->bInterfaceNumber;

	/* find the endpoints that we need */
	for (i = 0; i < interface->bNumEndpoints; ++i) {
		endpoint = &interface->endpoint[i];

		if ((endpoint->bEndpointAddress & 0x80) &&
		    ((endpoint->bmAttributes & 3) == 0x02)) {
			/* we found a bulk in endpoint */
			dbg("found bulk in");
			bulk_in_endpoint[num_bulk_in] = endpoint;
			++num_bulk_in;
		}

		if (((endpoint->bEndpointAddress & 0x80) == 0x00) &&
		    ((endpoint->bmAttributes & 3) == 0x02)) {
			/* we found a bulk out endpoint */
			dbg("found bulk out");
			bulk_out_endpoint[num_bulk_out] = endpoint;
			++num_bulk_out;
		}

		if ((endpoint->bEndpointAddress & 0x80) &&
		    ((endpoint->bmAttributes & 3) == 0x03)) {
			/* we found a interrupt in endpoint */
			dbg("found interrupt in");
			interrupt_in_endpoint[num_interrupt_in] = endpoint;
			++num_interrupt_in;
		}
	}

	/* according to the spec, we can only have 1 bulk_in, 1 bulk_out, and 1 interrupt_in endpoints */
	if ((num_bulk_in != 1) ||
	    (num_bulk_out != 1) ||
	    (num_interrupt_in != 1)) {
		dbg (__FUNCTION__ " - improper number of endpoints. Bluetooth driver not bound.");
		return NULL;
	}

	MOD_INC_USE_COUNT;
	info("USB Bluetooth converter detected");

	for (minor = 0; minor < BLUETOOTH_TTY_MINORS && bluetooth_table[minor]; ++minor)
		;
	if (bluetooth_table[minor]) {
		err("No more free Bluetooth devices");
		MOD_DEC_USE_COUNT;
		return NULL;
	}

	if (!(bluetooth = kmalloc(sizeof(struct usb_bluetooth), GFP_KERNEL))) {
		err("Out of memory");
		MOD_DEC_USE_COUNT;
		return NULL;
	}

	memset(bluetooth, 0, sizeof(struct usb_bluetooth));

	bluetooth->magic = USB_BLUETOOTH_MAGIC;
	bluetooth->dev = dev;
	bluetooth->minor = minor;
	bluetooth->tqueue.routine = bluetooth_softint;
	bluetooth->tqueue.data = bluetooth;

	/* record the interface number for the control out */
	bluetooth->control_out_bInterfaceNum = control_out_endpoint;
	
	/* create our control out urb pool */ 
	for (i = 0; i < NUM_CONTROL_URBS; ++i) {
		struct urb  *urb = usb_alloc_urb(0);
		if (urb == NULL) {
			err("No free urbs available");
			goto probe_error;
		}
		urb->transfer_buffer = NULL;
		bluetooth->control_urb_pool[i] = urb;
	}

	/* set up the endpoint information */
	endpoint = bulk_in_endpoint[0];
	bluetooth->read_urb = usb_alloc_urb (0);
	if (!bluetooth->read_urb) {
		err("No free urbs available");
		goto probe_error;
	}
	bluetooth->bulk_in_buffer_size = buffer_size = endpoint->wMaxPacketSize;
	bluetooth->bulk_in_endpointAddress = endpoint->bEndpointAddress;
	bluetooth->bulk_in_buffer = kmalloc (buffer_size, GFP_KERNEL);
	if (!bluetooth->bulk_in_buffer) {
		err("Couldn't allocate bulk_in_buffer");
		goto probe_error;
	}
	FILL_BULK_URB(bluetooth->read_urb, dev, usb_rcvbulkpipe(dev, endpoint->bEndpointAddress),
		      bluetooth->bulk_in_buffer, buffer_size, bluetooth_read_bulk_callback, bluetooth);

	endpoint = bulk_out_endpoint[0];
	bluetooth->bulk_out_endpointAddress = endpoint->bEndpointAddress;
	
	/* create our write urb pool */ 
	for (i = 0; i < NUM_BULK_URBS; ++i) {
		struct urb  *urb = usb_alloc_urb(0);
		if (urb == NULL) {
			err("No free urbs available");
			goto probe_error;
		}
		urb->transfer_buffer = NULL;
		bluetooth->write_urb_pool[i] = urb;
	}
	
	bluetooth->bulk_out_buffer_size = endpoint->wMaxPacketSize * 2;

	endpoint = interrupt_in_endpoint[0];
	bluetooth->interrupt_in_urb = usb_alloc_urb(0);
	if (!bluetooth->interrupt_in_urb) {
		err("No free urbs available");
		goto probe_error;
	}
	bluetooth->interrupt_in_buffer_size = buffer_size = endpoint->wMaxPacketSize;
	bluetooth->interrupt_in_endpointAddress = endpoint->bEndpointAddress;
	bluetooth->interrupt_in_interval = endpoint->bInterval;
	bluetooth->interrupt_in_buffer = kmalloc (buffer_size, GFP_KERNEL);
	if (!bluetooth->interrupt_in_buffer) {
		err("Couldn't allocate interrupt_in_buffer");
		goto probe_error;
	}
	FILL_INT_URB(bluetooth->interrupt_in_urb, dev, usb_rcvintpipe(dev, endpoint->bEndpointAddress),
		     bluetooth->interrupt_in_buffer, buffer_size, bluetooth_int_callback,
		     bluetooth, endpoint->bInterval);

	/* initialize the devfs nodes for this device and let the user know what bluetooths we are bound to */
	tty_register_devfs (&bluetooth_tty_driver, 0, minor);
	info("Bluetooth converter now attached to ttyUB%d (or usb/ttub/%d for devfs)", minor, minor);

	bluetooth_table[minor] = bluetooth;

	return bluetooth; /* success */

probe_error:
	if (bluetooth->read_urb)
		usb_free_urb (bluetooth->read_urb);
	if (bluetooth->bulk_in_buffer)
		kfree (bluetooth->bulk_in_buffer);
	if (bluetooth->interrupt_in_urb)
		usb_free_urb (bluetooth->interrupt_in_urb);
	if (bluetooth->interrupt_in_buffer)
		kfree (bluetooth->interrupt_in_buffer);
	for (i = 0; i < NUM_BULK_URBS; ++i)
		if (bluetooth->write_urb_pool[i])
			usb_free_urb (bluetooth->write_urb_pool[i]);
	for (i = 0; i < NUM_CONTROL_URBS; ++i) 
		if (bluetooth->control_urb_pool[i])
			usb_free_urb (bluetooth->control_urb_pool[i]);

	bluetooth_table[minor] = NULL;

	/* free up any memory that we allocated */
	kfree (bluetooth);
	MOD_DEC_USE_COUNT;
	return NULL;
}


static void usb_bluetooth_disconnect(struct usb_device *dev, void *ptr)
{
	struct usb_bluetooth *bluetooth = (struct usb_bluetooth *) ptr;
	int i;

	if (bluetooth) {
		if ((bluetooth->active) && (bluetooth->tty))
			tty_hangup(bluetooth->tty);

		bluetooth->active = 0;

		if (bluetooth->read_urb) {
			usb_unlink_urb (bluetooth->read_urb);
			usb_free_urb (bluetooth->read_urb);
		}
		if (bluetooth->bulk_in_buffer)
			kfree (bluetooth->bulk_in_buffer);

		if (bluetooth->interrupt_in_urb) {
			usb_unlink_urb (bluetooth->interrupt_in_urb);
			usb_free_urb (bluetooth->interrupt_in_urb);
		}
		if (bluetooth->interrupt_in_buffer)
			kfree (bluetooth->interrupt_in_buffer);

		tty_unregister_devfs (&bluetooth_tty_driver, bluetooth->minor);

		for (i = 0; i < NUM_BULK_URBS; ++i) {
			if (bluetooth->write_urb_pool[i]) {
				usb_unlink_urb (bluetooth->write_urb_pool[i]);
				if (bluetooth->write_urb_pool[i]->transfer_buffer)
					kfree (bluetooth->write_urb_pool[i]->transfer_buffer);
				usb_free_urb (bluetooth->write_urb_pool[i]);
			}
		}
		for (i = 0; i < NUM_CONTROL_URBS; ++i) {
			if (bluetooth->control_urb_pool[i]) {
				usb_unlink_urb (bluetooth->control_urb_pool[i]);
				if (bluetooth->control_urb_pool[i]->transfer_buffer)
					kfree (bluetooth->control_urb_pool[i]->transfer_buffer);
				usb_free_urb (bluetooth->control_urb_pool[i]);
			}
		}
		
		info("Bluetooth converter now disconnected from ttyUB%d", bluetooth->minor);

		bluetooth_table[bluetooth->minor] = NULL;

		/* free up any memory that we allocated */
		kfree (bluetooth);

	} else {
		info("device disconnected");
	}

	MOD_DEC_USE_COUNT;
}


static struct tty_driver bluetooth_tty_driver = {
	magic:			TTY_DRIVER_MAGIC,
	driver_name:		"usb-bluetooth",
	name:			"usb/ttub/%d",
	major:			BLUETOOTH_TTY_MAJOR,
	minor_start:		0,
	num:			BLUETOOTH_TTY_MINORS,
	type:			TTY_DRIVER_TYPE_SERIAL,
	subtype:		SERIAL_TYPE_NORMAL,
	flags:			TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS,

	refcount:		&bluetooth_refcount,
	table:			bluetooth_tty,
	termios:		bluetooth_termios,
	termios_locked:		bluetooth_termios_locked,

	open:			bluetooth_open,
	close:			bluetooth_close,
	write:			bluetooth_write,
	write_room:		bluetooth_write_room,
	ioctl:			bluetooth_ioctl,
	set_termios:		bluetooth_set_termios,
	throttle:		bluetooth_throttle,
	unthrottle:		bluetooth_unthrottle,
	chars_in_buffer:	bluetooth_chars_in_buffer,
};


int usb_bluetooth_init(void)
{
	int i;
	int result;

	/* Initalize our global data */
	for (i = 0; i < BLUETOOTH_TTY_MINORS; ++i) {
		bluetooth_table[i] = NULL;
	}

	info ("USB Bluetooth support registered");

	/* register the tty driver */
	bluetooth_tty_driver.init_termios          = tty_std_termios;
	bluetooth_tty_driver.init_termios.c_cflag  = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
	if (tty_register_driver (&bluetooth_tty_driver)) {
		err(__FUNCTION__ " - failed to register tty driver");
		return -1;
	}

	/* register the USB driver */
	result = usb_register(&usb_bluetooth_driver);
	if (result < 0) {
		tty_unregister_driver(&bluetooth_tty_driver);
		err("usb_register failed for the USB bluetooth driver. Error number %d", result);
		return -1;
	}

	return 0;
}


void usb_bluetooth_exit(void)
{
	usb_deregister(&usb_bluetooth_driver);
	tty_unregister_driver(&bluetooth_tty_driver);
}


module_init(usb_bluetooth_init);
module_exit(usb_bluetooth_exit);