[mirror_ubuntu-bionic-kernel.git] / drivers / usb / serial / aircable.c

/*
 * AIRcable USB Bluetooth Dongle Driver.
 *
 * Copyright (C) 2006 Manuel Francisco Naranjo (naranjo.manuel@gmail.com)
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the
 * Free Software Foundation.
 *
 * The device works as an standard CDC device, it has 2 interfaces, the first
 * one is for firmware access and the second is the serial one.
 * The protocol is very simply, there are two posibilities reading or writing.
 * When writing the first urb must have a Header that starts with 0x20 0x29 the
 * next two bytes must say how much data will be sended.
 * When reading the process is almost equal except that the header starts with
 * 0x00 0x20.
 *
 * The device simply need some stuff to understand data comming from the usb
 * buffer: The First and Second byte is used for a Header, the Third and Fourth
 * tells the  device the amount of information the package holds.
 * Packages are 60 bytes long Header Stuff.
 * When writing to the device the first two bytes of the header are 0x20 0x29
 * When reading the bytes are 0x00 0x20, or 0x00 0x10, there is an strange
 * situation, when too much data arrives to the device because it sends the data
 * but with out the header. I will use a simply hack to override this situation,
 * if there is data coming that does not contain any header, then that is data
 * that must go directly to the tty, as there is no documentation about if there
 * is any other control code, I will simply check for the first
 * one.
 *
 * The driver registers himself with the USB-serial core and the USB Core. I had
 * to implement a probe function agains USB-serial, because other way, the
 * driver was attaching himself to both interfaces. I have tryed with different
 * configurations of usb_serial_driver with out exit, only the probe function
 * could handle this correctly.
 *
 * I have taken some info from a Greg Kroah-Hartman article:
 * http://www.linuxjournal.com/article/6573
 * And from Linux Device Driver Kit CD, which is a great work, the authors taken
 * the work to recompile lots of information an knowladge in drivers development
 * and made it all avaible inside a cd.
 * URL: http://kernel.org/pub/linux/kernel/people/gregkh/ddk/
 *
 */

#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/circ_buf.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>

static int debug;

/* Vendor and Product ID */
#define AIRCABLE_VID		0x16CA
#define AIRCABLE_USB_PID	0x1502

/* write buffer size defines */
#define AIRCABLE_BUF_SIZE	2048

/* Protocol Stuff */
#define HCI_HEADER_LENGTH	0x4
#define TX_HEADER_0		0x20
#define TX_HEADER_1		0x29
#define RX_HEADER_0		0x00
#define RX_HEADER_1		0x20
#define MAX_HCI_FRAMESIZE	60
#define HCI_COMPLETE_FRAME	64

/* rx_flags */
#define THROTTLED		0x01
#define ACTUALLY_THROTTLED	0x02

/*
 * Version Information
 */
#define DRIVER_VERSION "v1.0b2"
#define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>"
#define DRIVER_DESC "AIRcable USB Driver"

/* ID table that will be registered with USB core */
static struct usb_device_id id_table [] = {
	{ USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) },
	{ },
};
MODULE_DEVICE_TABLE(usb, id_table);


/* Internal Structure */
struct aircable_private {
	spinlock_t rx_lock;		/* spinlock for the receive lines */
	struct circ_buf *tx_buf;	/* write buffer */
	struct circ_buf *rx_buf;	/* read buffer */
	int rx_flags;			/* for throttilng */
	struct work_struct rx_work;	/* work cue for the receiving line */
	struct usb_serial_port *port;	/* USB port with which associated */
};

/* Private methods */

/* Circular Buffer Methods, code from ti_usb_3410_5052 used */
/*
 * serial_buf_clear
 *
 * Clear out all data in the circular buffer.
 */
static void serial_buf_clear(struct circ_buf *cb)
{
	cb->head = cb->tail = 0;
}

/*
 * serial_buf_alloc
 *
 * Allocate a circular buffer and all associated memory.
 */
static struct circ_buf *serial_buf_alloc(void)
{
	struct circ_buf *cb;
	cb = kmalloc(sizeof(struct circ_buf), GFP_KERNEL);
	if (cb == NULL)
		return NULL;
	cb->buf = kmalloc(AIRCABLE_BUF_SIZE, GFP_KERNEL);
	if (cb->buf == NULL) {
		kfree(cb);
		return NULL;
	}
	serial_buf_clear(cb);
	return cb;
}

/*
 * serial_buf_free
 *
 * Free the buffer and all associated memory.
 */
static void serial_buf_free(struct circ_buf *cb)
{
	kfree(cb->buf);
	kfree(cb);
}

/*
 * serial_buf_data_avail
 *
 * Return the number of bytes of data available in the circular
 * buffer.
 */
static int serial_buf_data_avail(struct circ_buf *cb)
{
	return CIRC_CNT(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
}

/*
 * serial_buf_put
 *
 * Copy data data from a user buffer and put it into the circular buffer.
 * Restrict to the amount of space available.
 *
 * Return the number of bytes copied.
 */
static int serial_buf_put(struct circ_buf *cb, const char *buf, int count)
{
	int c, ret = 0;
	while (1) {
		c = CIRC_SPACE_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
		if (count < c)
			c = count;
		if (c <= 0)
			break;
		memcpy(cb->buf + cb->head, buf, c);
		cb->head = (cb->head + c) & (AIRCABLE_BUF_SIZE-1);
		buf += c;
		count -= c;
		ret = c;
	}
	return ret;
}

/*
 * serial_buf_get
 *
 * Get data from the circular buffer and copy to the given buffer.
 * Restrict to the amount of data available.
 *
 * Return the number of bytes copied.
 */
static int serial_buf_get(struct circ_buf *cb, char *buf, int count)
{
	int c, ret = 0;
	while (1) {
		c = CIRC_CNT_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
		if (count < c)
			c = count;
		if (c <= 0)
			break;
		memcpy(buf, cb->buf + cb->tail, c);
		cb->tail = (cb->tail + c) & (AIRCABLE_BUF_SIZE-1);
		buf += c;
		count -= c;
		ret = c;
	}
	return ret;
}

/* End of circula buffer methods */

static void aircable_send(struct usb_serial_port *port)
{
	int count, result;
	struct aircable_private *priv = usb_get_serial_port_data(port);
	unsigned char *buf;
	__le16 *dbuf;
	dbg("%s - port %d", __func__, port->number);
	if (port->write_urb_busy)
		return;

	count = min(serial_buf_data_avail(priv->tx_buf), MAX_HCI_FRAMESIZE);
	if (count == 0)
		return;

	buf = kzalloc(count + HCI_HEADER_LENGTH, GFP_ATOMIC);
	if (!buf) {
		err("%s- kzalloc(%d) failed.", __func__,
		    count + HCI_HEADER_LENGTH);
		return;
	}

	buf[0] = TX_HEADER_0;
	buf[1] = TX_HEADER_1;
	dbuf = (__le16 *)&buf[2];
	*dbuf = cpu_to_le16((u16)count);
	serial_buf_get(priv->tx_buf, buf + HCI_HEADER_LENGTH,
							MAX_HCI_FRAMESIZE);

	memcpy(port->write_urb->transfer_buffer, buf,
	       count + HCI_HEADER_LENGTH);

	kfree(buf);
	port->write_urb_busy = 1;
	usb_serial_debug_data(debug, &port->dev, __func__,
			      count + HCI_HEADER_LENGTH,
			      port->write_urb->transfer_buffer);
	port->write_urb->transfer_buffer_length = count + HCI_HEADER_LENGTH;
	port->write_urb->dev = port->serial->dev;
	result = usb_submit_urb(port->write_urb, GFP_ATOMIC);

	if (result) {
		dev_err(&port->dev,
			"%s - failed submitting write urb, error %d\n",
			__func__, result);
		port->write_urb_busy = 0;
	}

	schedule_work(&port->work);
}

static void aircable_read(struct work_struct *work)
{
	struct aircable_private *priv =
		container_of(work, struct aircable_private, rx_work);
	struct usb_serial_port *port = priv->port;
	struct tty_struct *tty;
	unsigned char *data;
	int count;
	if (priv->rx_flags & THROTTLED) {
		if (priv->rx_flags & ACTUALLY_THROTTLED)
			schedule_work(&priv->rx_work);
		return;
	}

	/* By now I will flush data to the tty in packages of no more than
	 * 64 bytes, to ensure I do not get throttled.
	 * Ask USB mailing list for better aproach.
	 */
	tty = port->port.tty;

	if (!tty) {
		schedule_work(&priv->rx_work);
		err("%s - No tty available", __func__);
		return ;
	}

	count = min(64, serial_buf_data_avail(priv->rx_buf));

	if (count <= 0)
		return; /* We have finished sending everything. */

	tty_prepare_flip_string(tty, &data, count);
	if (!data) {
		err("%s- kzalloc(%d) failed.", __func__, count);
		return;
	}

	serial_buf_get(priv->rx_buf, data, count);

	tty_flip_buffer_push(tty);

	if (serial_buf_data_avail(priv->rx_buf))
		schedule_work(&priv->rx_work);

	return;
}
/* End of private methods */

static int aircable_probe(struct usb_serial *serial,
			  const struct usb_device_id *id)
{
	struct usb_host_interface *iface_desc = serial->interface->
								cur_altsetting;
	struct usb_endpoint_descriptor *endpoint;
	int num_bulk_out = 0;
	int i;

	for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
		endpoint = &iface_desc->endpoint[i].desc;
		if (usb_endpoint_is_bulk_out(endpoint)) {
			dbg("found bulk out on endpoint %d", i);
			++num_bulk_out;
		}
	}

	if (num_bulk_out == 0) {
		dbg("Invalid interface, discarding");
		return -ENODEV;
	}

	return 0;
}

static int aircable_attach(struct usb_serial *serial)
{
	struct usb_serial_port *port = serial->port[0];
	struct aircable_private *priv;

	priv = kzalloc(sizeof(struct aircable_private), GFP_KERNEL);
	if (!priv) {
		err("%s- kmalloc(%Zd) failed.", __func__,
			sizeof(struct aircable_private));
		return -ENOMEM;
	}

	/* Allocation of Circular Buffers */
	priv->tx_buf = serial_buf_alloc();
	if (priv->tx_buf == NULL) {
		kfree(priv);
		return -ENOMEM;
	}

	priv->rx_buf = serial_buf_alloc();
	if (priv->rx_buf == NULL) {
		kfree(priv->tx_buf);
		kfree(priv);
		return -ENOMEM;
	}

	priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
	priv->port = port;
	INIT_WORK(&priv->rx_work, aircable_read);

	usb_set_serial_port_data(serial->port[0], priv);

	return 0;
}

static void aircable_shutdown(struct usb_serial *serial)
{

	struct usb_serial_port *port = serial->port[0];
	struct aircable_private *priv = usb_get_serial_port_data(port);

	dbg("%s", __func__);

	if (priv) {
		serial_buf_free(priv->tx_buf);
		serial_buf_free(priv->rx_buf);
		usb_set_serial_port_data(port, NULL);
		kfree(priv);
	}
}

static int aircable_write_room(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct aircable_private *priv = usb_get_serial_port_data(port);
	return serial_buf_data_avail(priv->tx_buf);
}

static int aircable_write(struct tty_struct *tty, struct usb_serial_port *port,
			  const unsigned char *source, int count)
{
	struct aircable_private *priv = usb_get_serial_port_data(port);
	int temp;

	dbg("%s - port %d, %d bytes", __func__, port->number, count);

	usb_serial_debug_data(debug, &port->dev, __func__, count, source);

	if (!count) {
		dbg("%s - write request of 0 bytes", __func__);
		return count;
	}

	temp = serial_buf_put(priv->tx_buf, source, count);

	aircable_send(port);

	if (count > AIRCABLE_BUF_SIZE)
		count = AIRCABLE_BUF_SIZE;

	return count;

}

static void aircable_write_bulk_callback(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	int status = urb->status;
	int result;

	dbg("%s - urb status: %d", __func__ , status);

	/* This has been taken from cypress_m8.c cypress_write_int_callback */
	switch (status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dbg("%s - urb shutting down with status: %d",
		    __func__, status);
		port->write_urb_busy = 0;
		return;
	default:
		/* error in the urb, so we have to resubmit it */
		dbg("%s - Overflow in write", __func__);
		dbg("%s - nonzero write bulk status received: %d",
		    __func__, status);
		port->write_urb->transfer_buffer_length = 1;
		port->write_urb->dev = port->serial->dev;
		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
		if (result)
			dev_err(&urb->dev->dev,
			    "%s - failed resubmitting write urb, error %d\n",
							__func__, result);
		else
			return;
	}

	port->write_urb_busy = 0;

	aircable_send(port);
}

static void aircable_read_bulk_callback(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	struct aircable_private *priv = usb_get_serial_port_data(port);
	struct tty_struct *tty;
	unsigned long no_packages, remaining, package_length, i;
	int result, shift = 0;
	unsigned char *temp;
	int status = urb->status;

	dbg("%s - port %d", __func__, port->number);

	if (status) {
		dbg("%s - urb status = %d", __func__, status);
		if (!port->port.count) {
			dbg("%s - port is closed, exiting.", __func__);
			return;
		}
		if (status == -EPROTO) {
			dbg("%s - caught -EPROTO, resubmitting the urb",
			    __func__);
			usb_fill_bulk_urb(port->read_urb, port->serial->dev,
				usb_rcvbulkpipe(port->serial->dev,
					port->bulk_in_endpointAddress),
				port->read_urb->transfer_buffer,
				port->read_urb->transfer_buffer_length,
				aircable_read_bulk_callback, port);

			result = usb_submit_urb(urb, GFP_ATOMIC);
			if (result)
				dev_err(&urb->dev->dev,
					"%s - failed resubmitting read urb, error %d\n",
					__func__, result);
			return;
		}
		dbg("%s - unable to handle the error, exiting.", __func__);
		return;
	}

	usb_serial_debug_data(debug, &port->dev, __func__,
				urb->actual_length, urb->transfer_buffer);

	tty = port->port.tty;
	if (tty && urb->actual_length) {
		if (urb->actual_length <= 2) {
			/* This is an incomplete package */
			serial_buf_put(priv->rx_buf, urb->transfer_buffer,
				       urb->actual_length);
		} else {
			temp = urb->transfer_buffer;
			if (temp[0] == RX_HEADER_0)
				shift = HCI_HEADER_LENGTH;

			remaining = urb->actual_length;
			no_packages = urb->actual_length / (HCI_COMPLETE_FRAME);

			if (urb->actual_length % HCI_COMPLETE_FRAME != 0)
				no_packages++;

			for (i = 0; i < no_packages; i++) {
				if (remaining > (HCI_COMPLETE_FRAME))
					package_length = HCI_COMPLETE_FRAME;
				else
					package_length = remaining;
				remaining -= package_length;

				serial_buf_put(priv->rx_buf,
					urb->transfer_buffer + shift +
					(HCI_COMPLETE_FRAME) * (i),
					package_length - shift);
			}
		}
		aircable_read(&priv->rx_work);
	}

	/* Schedule the next read _if_ we are still open */
	if (port->port.count) {
		usb_fill_bulk_urb(port->read_urb, port->serial->dev,
				  usb_rcvbulkpipe(port->serial->dev,
					  port->bulk_in_endpointAddress),
				  port->read_urb->transfer_buffer,
				  port->read_urb->transfer_buffer_length,
				  aircable_read_bulk_callback, port);

		result = usb_submit_urb(urb, GFP_ATOMIC);
		if (result)
			dev_err(&urb->dev->dev,
				"%s - failed resubmitting read urb, error %d\n",
				__func__, result);
	}

	return;
}

/* Based on ftdi_sio.c throttle */
static void aircable_throttle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct aircable_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;

	dbg("%s - port %d", __func__, port->number);

	spin_lock_irqsave(&priv->rx_lock, flags);
	priv->rx_flags |= THROTTLED;
	spin_unlock_irqrestore(&priv->rx_lock, flags);
}

/* Based on ftdi_sio.c unthrottle */
static void aircable_unthrottle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct aircable_private *priv = usb_get_serial_port_data(port);
	int actually_throttled;
	unsigned long flags;

	dbg("%s - port %d", __func__, port->number);

	spin_lock_irqsave(&priv->rx_lock, flags);
	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
	priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
	spin_unlock_irqrestore(&priv->rx_lock, flags);

	if (actually_throttled)
		schedule_work(&priv->rx_work);
}

static struct usb_driver aircable_driver = {
	.name =		"aircable",
	.probe =	usb_serial_probe,
	.disconnect =	usb_serial_disconnect,
	.id_table =	id_table,
	.no_dynamic_id =	1,
};

static struct usb_serial_driver aircable_device = {
	.driver = {
		.owner =	THIS_MODULE,
		.name =		"aircable",
	},
	.usb_driver = 		&aircable_driver,
	.id_table = 		id_table,
	.num_ports =		1,
	.attach =		aircable_attach,
	.probe =		aircable_probe,
	.shutdown =		aircable_shutdown,
	.write =		aircable_write,
	.write_room =		aircable_write_room,
	.write_bulk_callback =	aircable_write_bulk_callback,
	.read_bulk_callback =	aircable_read_bulk_callback,
	.throttle =		aircable_throttle,
	.unthrottle =		aircable_unthrottle,
};

static int __init aircable_init(void)
{
	int retval;
	retval = usb_serial_register(&aircable_device);
	if (retval)
		goto failed_serial_register;
	retval = usb_register(&aircable_driver);
	if (retval)
		goto failed_usb_register;
	return 0;

failed_serial_register:
	usb_serial_deregister(&aircable_device);
failed_usb_register:
	return retval;
}

static void __exit aircable_exit(void)
{
	usb_deregister(&aircable_driver);
	usb_serial_deregister(&aircable_device);
}

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL");

module_init(aircable_init);
module_exit(aircable_exit);

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");
Commit	Line	Data
3fe70ba2 MFN	1	/*
	2	* AIRcable USB Bluetooth Dongle Driver.
	3	*
	4	* Copyright (C) 2006 Manuel Francisco Naranjo (naranjo.manuel@gmail.com)
	5	* This program is free software; you can redistribute it and/or modify it under
	6	* the terms of the GNU General Public License version 2 as published by the
	7	* Free Software Foundation.
	8	*
	9	* The device works as an standard CDC device, it has 2 interfaces, the first
	10	* one is for firmware access and the second is the serial one.
	11	* The protocol is very simply, there are two posibilities reading or writing.
beb7dd86	12	* When writing the first urb must have a Header that starts with 0x20 0x29 the
3fe70ba2 MFN	13	* next two bytes must say how much data will be sended.
	14	* When reading the process is almost equal except that the header starts with
	15	* 0x00 0x20.
	16	*
	17	* The device simply need some stuff to understand data comming from the usb
	18	* buffer: The First and Second byte is used for a Header, the Third and Fourth
	19	* tells the device the amount of information the package holds.
	20	* Packages are 60 bytes long Header Stuff.
beb7dd86	21	* When writing to the device the first two bytes of the header are 0x20 0x29
3fe70ba2 MFN	22	* When reading the bytes are 0x00 0x20, or 0x00 0x10, there is an strange
	23	* situation, when too much data arrives to the device because it sends the data
	24	* but with out the header. I will use a simply hack to override this situation,
	25	* if there is data coming that does not contain any header, then that is data
	26	* that must go directly to the tty, as there is no documentation about if there
	27	* is any other control code, I will simply check for the first
	28	* one.
	29	*
	30	* The driver registers himself with the USB-serial core and the USB Core. I had
	31	* to implement a probe function agains USB-serial, because other way, the
	32	* driver was attaching himself to both interfaces. I have tryed with different
	33	* configurations of usb_serial_driver with out exit, only the probe function
	34	* could handle this correctly.
	35	*
	36	* I have taken some info from a Greg Kroah-Hartman article:
	37	* http://www.linuxjournal.com/article/6573
	38	* And from Linux Device Driver Kit CD, which is a great work, the authors taken
	39	* the work to recompile lots of information an knowladge in drivers development
	40	* and made it all avaible inside a cd.
	41	* URL: http://kernel.org/pub/linux/kernel/people/gregkh/ddk/
	42	*
	43	*/
	44
	45	#include <linux/tty.h>
	46	#include <linux/tty_flip.h>
	47	#include <linux/circ_buf.h>
	48	#include <linux/usb.h>
	49	#include <linux/usb/serial.h>
	50
	51	static int debug;
	52
	53	/* Vendor and Product ID */
	54	#define AIRCABLE_VID 0x16CA
	55	#define AIRCABLE_USB_PID 0x1502
	56
	57	/* write buffer size defines */
	58	#define AIRCABLE_BUF_SIZE 2048
	59
	60	/* Protocol Stuff */
	61	#define HCI_HEADER_LENGTH 0x4
	62	#define TX_HEADER_0 0x20
	63	#define TX_HEADER_1 0x29
	64	#define RX_HEADER_0 0x00
	65	#define RX_HEADER_1 0x20
	66	#define MAX_HCI_FRAMESIZE 60
	67	#define HCI_COMPLETE_FRAME 64
	68
	69	/* rx_flags */
	70	#define THROTTLED 0x01
	71	#define ACTUALLY_THROTTLED 0x02
	72
	73	/*
	74	* Version Information
	75	*/
	76	#define DRIVER_VERSION "v1.0b2"
	77	#define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>"
	78	#define DRIVER_DESC "AIRcable USB Driver"
	79
	80	/* ID table that will be registered with USB core */
	81	static struct usb_device_id id_table [] = {
	82	{ USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) },
	83	{ },
	84	};
	85	MODULE_DEVICE_TABLE(usb, id_table);
86
87
88	/* Internal Structure */
89	struct aircable_private {
90	spinlock_t rx_lock; /* spinlock for the receive lines */
91	struct circ_buf tx_buf; / write buffer */
92	struct circ_buf rx_buf; / read buffer */
93	int rx_flags; /* for throttilng */
94	struct work_struct rx_work; /* work cue for the receiving line */
c4028958	95	struct usb_serial_port port; / USB port with which associated */
3fe70ba2 MFN	96	};
	97
	98	/* Private methods */
	99
	100	/* Circular Buffer Methods, code from ti_usb_3410_5052 used */
	101	/*
	102	* serial_buf_clear
	103	*
	104	* Clear out all data in the circular buffer.
	105	*/
	106	static void serial_buf_clear(struct circ_buf *cb)
	107	{
	108	cb->head = cb->tail = 0;
	109	}
	110
	111	/*
	112	* serial_buf_alloc
	113	*
	114	* Allocate a circular buffer and all associated memory.
	115	*/
	116	static struct circ_buf *serial_buf_alloc(void)
	117	{
	118	struct circ_buf *cb;
	119	cb = kmalloc(sizeof(struct circ_buf), GFP_KERNEL);
	120	if (cb == NULL)
	121	return NULL;
	122	cb->buf = kmalloc(AIRCABLE_BUF_SIZE, GFP_KERNEL);
	123	if (cb->buf == NULL) {
	124	kfree(cb);
	125	return NULL;
	126	}
	127	serial_buf_clear(cb);
	128	return cb;
	129	}
	130
	131	/*
	132	* serial_buf_free
	133	*
	134	* Free the buffer and all associated memory.
	135	*/
	136	static void serial_buf_free(struct circ_buf *cb)
	137	{
	138	kfree(cb->buf);
	139	kfree(cb);
	140	}
	141
	142	/*
	143	* serial_buf_data_avail
	144	*
	145	* Return the number of bytes of data available in the circular
	146	* buffer.
	147	*/
	148	static int serial_buf_data_avail(struct circ_buf *cb)
	149	{
c4d0f8cb	150	return CIRC_CNT(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
3fe70ba2 MFN	151	}
	152
	153	/*
	154	* serial_buf_put
	155	*
	156	* Copy data data from a user buffer and put it into the circular buffer.
	157	* Restrict to the amount of space available.
	158	*
	159	* Return the number of bytes copied.
	160	*/
	161	static int serial_buf_put(struct circ_buf cb, const char buf, int count)
	162	{
	163	int c, ret = 0;
	164	while (1) {
	165	c = CIRC_SPACE_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
	166	if (count < c)
	167	c = count;
	168	if (c <= 0)
	169	break;
	170	memcpy(cb->buf + cb->head, buf, c);
	171	cb->head = (cb->head + c) & (AIRCABLE_BUF_SIZE-1);
	172	buf += c;
	173	count -= c;
c4d0f8cb	174	ret = c;
3fe70ba2 MFN	175	}
	176	return ret;
	177	}
	178
	179	/*
	180	* serial_buf_get
	181	*
	182	* Get data from the circular buffer and copy to the given buffer.
	183	* Restrict to the amount of data available.
	184	*
	185	* Return the number of bytes copied.
	186	*/
	187	static int serial_buf_get(struct circ_buf cb, char buf, int count)
	188	{
	189	int c, ret = 0;
	190	while (1) {
	191	c = CIRC_CNT_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
	192	if (count < c)
	193	c = count;
	194	if (c <= 0)
	195	break;
	196	memcpy(buf, cb->buf + cb->tail, c);
	197	cb->tail = (cb->tail + c) & (AIRCABLE_BUF_SIZE-1);
	198	buf += c;
	199	count -= c;
c4d0f8cb	200	ret = c;
3fe70ba2 MFN	201	}
	202	return ret;
	203	}
	204
	205	/* End of circula buffer methods */
	206
	207	static void aircable_send(struct usb_serial_port *port)
	208	{
	209	int count, result;
	210	struct aircable_private *priv = usb_get_serial_port_data(port);
c4d0f8cb	211	unsigned char *buf;
fd05e720	212	__le16 *dbuf;
441b62c1	213	dbg("%s - port %d", __func__, port->number);
3fe70ba2 MFN	214	if (port->write_urb_busy)
	215	return;
	216
	217	count = min(serial_buf_data_avail(priv->tx_buf), MAX_HCI_FRAMESIZE);
	218	if (count == 0)
	219	return;
	220
	221	buf = kzalloc(count + HCI_HEADER_LENGTH, GFP_ATOMIC);
	222	if (!buf) {
441b62c1	223	err("%s- kzalloc(%d) failed.", __func__,
3fe70ba2 MFN	224	count + HCI_HEADER_LENGTH);
	225	return;
	226	}
	227
	228	buf[0] = TX_HEADER_0;
	229	buf[1] = TX_HEADER_1;
fd05e720	230	dbuf = (__le16 *)&buf[2];
b19d402a	231	*dbuf = cpu_to_le16((u16)count);
c4d0f8cb AC	232	serial_buf_get(priv->tx_buf, buf + HCI_HEADER_LENGTH,
c4d0f8cb AC	233	MAX_HCI_FRAMESIZE);
3fe70ba2 MFN	234
	235	memcpy(port->write_urb->transfer_buffer, buf,
	236	count + HCI_HEADER_LENGTH);
	237
	238	kfree(buf);
	239	port->write_urb_busy = 1;
441b62c1	240	usb_serial_debug_data(debug, &port->dev, __func__,
3fe70ba2 MFN	241	count + HCI_HEADER_LENGTH,
	242	port->write_urb->transfer_buffer);
	243	port->write_urb->transfer_buffer_length = count + HCI_HEADER_LENGTH;
	244	port->write_urb->dev = port->serial->dev;
	245	result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
	246
	247	if (result) {
	248	dev_err(&port->dev,
	249	"%s - failed submitting write urb, error %d\n",
441b62c1	250	__func__, result);
3fe70ba2 MFN	251	port->write_urb_busy = 0;
	252	}
	253
	254	schedule_work(&port->work);
	255	}
	256
c4028958	257	static void aircable_read(struct work_struct *work)
3fe70ba2	258	{
c4028958 DH	259	struct aircable_private *priv =
	260	container_of(work, struct aircable_private, rx_work);
	261	struct usb_serial_port *port = priv->port;
3fe70ba2 MFN	262	struct tty_struct *tty;
	263	unsigned char *data;
	264	int count;
c4d0f8cb	265	if (priv->rx_flags & THROTTLED) {
3fe70ba2 MFN	266	if (priv->rx_flags & ACTUALLY_THROTTLED)
	267	schedule_work(&priv->rx_work);
	268	return;
	269	}
	270
	271	/* By now I will flush data to the tty in packages of no more than
	272	* 64 bytes, to ensure I do not get throttled.
	273	* Ask USB mailing list for better aproach.
	274	*/
95da310e	275	tty = port->port.tty;
3fe70ba2	276
7a5c7b42	277	if (!tty) {
3fe70ba2	278	schedule_work(&priv->rx_work);
441b62c1	279	err("%s - No tty available", __func__);
7a5c7b42 NMF	280	return ;
7a5c7b42 NMF	281	}
3fe70ba2 MFN	282
	283	count = min(64, serial_buf_data_avail(priv->rx_buf));
	284
	285	if (count <= 0)
c4d0f8cb	286	return; /* We have finished sending everything. */
3fe70ba2 MFN	287
3fe70ba2 MFN	288	tty_prepare_flip_string(tty, &data, count);
c4d0f8cb	289	if (!data) {
441b62c1	290	err("%s- kzalloc(%d) failed.", __func__, count);
3fe70ba2 MFN	291	return;
	292	}
	293
	294	serial_buf_get(priv->rx_buf, data, count);
	295
	296	tty_flip_buffer_push(tty);
	297
	298	if (serial_buf_data_avail(priv->rx_buf))
	299	schedule_work(&priv->rx_work);
	300
	301	return;
	302	}
	303	/* End of private methods */
	304
	305	static int aircable_probe(struct usb_serial *serial,
	306	const struct usb_device_id *id)
	307	{
c4d0f8cb AC	308	struct usb_host_interface *iface_desc = serial->interface->
c4d0f8cb AC	309	cur_altsetting;
3fe70ba2	310	struct usb_endpoint_descriptor *endpoint;
c4d0f8cb	311	int num_bulk_out = 0;
3fe70ba2 MFN	312	int i;
	313
	314	for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
	315	endpoint = &iface_desc->endpoint[i].desc;
377f13bf	316	if (usb_endpoint_is_bulk_out(endpoint)) {
3fe70ba2 MFN	317	dbg("found bulk out on endpoint %d", i);
	318	++num_bulk_out;
	319	}
	320	}
	321
	322	if (num_bulk_out == 0) {
	323	dbg("Invalid interface, discarding");
	324	return -ENODEV;
	325	}
	326
	327	return 0;
	328	}
	329
c4d0f8cb	330	static int aircable_attach(struct usb_serial *serial)
3fe70ba2 MFN	331	{
	332	struct usb_serial_port *port = serial->port[0];
	333	struct aircable_private *priv;
	334
	335	priv = kzalloc(sizeof(struct aircable_private), GFP_KERNEL);
c4d0f8cb	336	if (!priv) {
441b62c1	337	err("%s- kmalloc(%Zd) failed.", __func__,
3fe70ba2 MFN	338	sizeof(struct aircable_private));
	339	return -ENOMEM;
	340	}
	341
	342	/* Allocation of Circular Buffers */
	343	priv->tx_buf = serial_buf_alloc();
	344	if (priv->tx_buf == NULL) {
	345	kfree(priv);
	346	return -ENOMEM;
	347	}
	348
	349	priv->rx_buf = serial_buf_alloc();
	350	if (priv->rx_buf == NULL) {
	351	kfree(priv->tx_buf);
	352	kfree(priv);
	353	return -ENOMEM;
	354	}
	355
	356	priv->rx_flags &= ~(THROTTLED \| ACTUALLY_THROTTLED);
c4028958 DH	357	priv->port = port;
c4028958 DH	358	INIT_WORK(&priv->rx_work, aircable_read);
3fe70ba2 MFN	359
	360	usb_set_serial_port_data(serial->port[0], priv);
	361
	362	return 0;
	363	}
	364
	365	static void aircable_shutdown(struct usb_serial *serial)
	366	{
	367
	368	struct usb_serial_port *port = serial->port[0];
	369	struct aircable_private *priv = usb_get_serial_port_data(port);
	370
441b62c1	371	dbg("%s", __func__);
3fe70ba2 MFN	372
	373	if (priv) {
	374	serial_buf_free(priv->tx_buf);
	375	serial_buf_free(priv->rx_buf);
	376	usb_set_serial_port_data(port, NULL);
	377	kfree(priv);
	378	}
	379	}
	380
95da310e	381	static int aircable_write_room(struct tty_struct *tty)
3fe70ba2	382	{
95da310e	383	struct usb_serial_port *port = tty->driver_data;
3fe70ba2 MFN	384	struct aircable_private *priv = usb_get_serial_port_data(port);
	385	return serial_buf_data_avail(priv->tx_buf);
	386	}
	387
95da310e	388	static int aircable_write(struct tty_struct tty, struct usb_serial_port port,
3fe70ba2 MFN	389	const unsigned char *source, int count)
	390	{
	391	struct aircable_private *priv = usb_get_serial_port_data(port);
	392	int temp;
	393
441b62c1	394	dbg("%s - port %d, %d bytes", __func__, port->number, count);
3fe70ba2	395
441b62c1	396	usb_serial_debug_data(debug, &port->dev, __func__, count, source);
3fe70ba2	397
c4d0f8cb	398	if (!count) {
441b62c1	399	dbg("%s - write request of 0 bytes", __func__);
3fe70ba2 MFN	400	return count;
	401	}
	402
	403	temp = serial_buf_put(priv->tx_buf, source, count);
	404
	405	aircable_send(port);
	406
	407	if (count > AIRCABLE_BUF_SIZE)
	408	count = AIRCABLE_BUF_SIZE;
	409
	410	return count;
	411
	412	}
	413
7d12e780	414	static void aircable_write_bulk_callback(struct urb *urb)
3fe70ba2 MFN	415	{
3fe70ba2 MFN	416	struct usb_serial_port *port = urb->context;
1373dbbc	417	int status = urb->status;
3fe70ba2 MFN	418	int result;
3fe70ba2 MFN	419
441b62c1	420	dbg("%s - urb status: %d", __func__ , status);
3fe70ba2 MFN	421
3fe70ba2 MFN	422	/* This has been taken from cypress_m8.c cypress_write_int_callback */
1373dbbc	423	switch (status) {
c4d0f8cb AC	424	case 0:
	425	/* success */
	426	break;
	427	case -ECONNRESET:
	428	case -ENOENT:
	429	case -ESHUTDOWN:
	430	/* this urb is terminated, clean up */
	431	dbg("%s - urb shutting down with status: %d",
	432	__func__, status);
	433	port->write_urb_busy = 0;
	434	return;
	435	default:
	436	/* error in the urb, so we have to resubmit it */
	437	dbg("%s - Overflow in write", __func__);
	438	dbg("%s - nonzero write bulk status received: %d",
	439	__func__, status);
	440	port->write_urb->transfer_buffer_length = 1;
	441	port->write_urb->dev = port->serial->dev;
	442	result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
	443	if (result)
	444	dev_err(&urb->dev->dev,
	445	"%s - failed resubmitting write urb, error %d\n",
	446	__func__, result);
	447	else
3fe70ba2	448	return;
3fe70ba2 MFN	449	}
	450
	451	port->write_urb_busy = 0;
	452
	453	aircable_send(port);
	454	}
	455
7d12e780	456	static void aircable_read_bulk_callback(struct urb *urb)
3fe70ba2 MFN	457	{
	458	struct usb_serial_port *port = urb->context;
	459	struct aircable_private *priv = usb_get_serial_port_data(port);
	460	struct tty_struct *tty;
	461	unsigned long no_packages, remaining, package_length, i;
	462	int result, shift = 0;
	463	unsigned char *temp;
1373dbbc	464	int status = urb->status;
3fe70ba2	465
441b62c1	466	dbg("%s - port %d", __func__, port->number);
3fe70ba2	467
1373dbbc	468	if (status) {
441b62c1	469	dbg("%s - urb status = %d", __func__, status);
95da310e	470	if (!port->port.count) {
441b62c1	471	dbg("%s - port is closed, exiting.", __func__);
3fe70ba2 MFN	472	return;
3fe70ba2 MFN	473	}
1373dbbc	474	if (status == -EPROTO) {
3fe70ba2	475	dbg("%s - caught -EPROTO, resubmitting the urb",
441b62c1	476	__func__);
3fe70ba2	477	usb_fill_bulk_urb(port->read_urb, port->serial->dev,
c4d0f8cb AC	478	usb_rcvbulkpipe(port->serial->dev,
	479	port->bulk_in_endpointAddress),
	480	port->read_urb->transfer_buffer,
	481	port->read_urb->transfer_buffer_length,
	482	aircable_read_bulk_callback, port);
3fe70ba2 MFN	483
	484	result = usb_submit_urb(urb, GFP_ATOMIC);
	485	if (result)
	486	dev_err(&urb->dev->dev,
	487	"%s - failed resubmitting read urb, error %d\n",
441b62c1	488	__func__, result);
3fe70ba2 MFN	489	return;
3fe70ba2 MFN	490	}
441b62c1	491	dbg("%s - unable to handle the error, exiting.", __func__);
3fe70ba2 MFN	492	return;
	493	}
	494
441b62c1	495	usb_serial_debug_data(debug, &port->dev, __func__,
c4d0f8cb	496	urb->actual_length, urb->transfer_buffer);
3fe70ba2	497
95da310e	498	tty = port->port.tty;
3fe70ba2 MFN	499	if (tty && urb->actual_length) {
	500	if (urb->actual_length <= 2) {
	501	/* This is an incomplete package */
	502	serial_buf_put(priv->rx_buf, urb->transfer_buffer,
	503	urb->actual_length);
	504	} else {
	505	temp = urb->transfer_buffer;
	506	if (temp[0] == RX_HEADER_0)
	507	shift = HCI_HEADER_LENGTH;
	508
	509	remaining = urb->actual_length;
	510	no_packages = urb->actual_length / (HCI_COMPLETE_FRAME);
	511
	512	if (urb->actual_length % HCI_COMPLETE_FRAME != 0)
c4d0f8cb	513	no_packages++;
3fe70ba2	514
c4d0f8cb	515	for (i = 0; i < no_packages; i++) {
3fe70ba2 MFN	516	if (remaining > (HCI_COMPLETE_FRAME))
	517	package_length = HCI_COMPLETE_FRAME;
	518	else
	519	package_length = remaining;
	520	remaining -= package_length;
	521
	522	serial_buf_put(priv->rx_buf,
	523	urb->transfer_buffer + shift +
	524	(HCI_COMPLETE_FRAME) * (i),
	525	package_length - shift);
	526	}
	527	}
c4028958	528	aircable_read(&priv->rx_work);
3fe70ba2 MFN	529	}
	530
	531	/* Schedule the next read _if_ we are still open */
95da310e	532	if (port->port.count) {
3fe70ba2 MFN	533	usb_fill_bulk_urb(port->read_urb, port->serial->dev,
3fe70ba2 MFN	534	usb_rcvbulkpipe(port->serial->dev,
c4d0f8cb	535	port->bulk_in_endpointAddress),
3fe70ba2 MFN	536	port->read_urb->transfer_buffer,
	537	port->read_urb->transfer_buffer_length,
	538	aircable_read_bulk_callback, port);
	539
	540	result = usb_submit_urb(urb, GFP_ATOMIC);
	541	if (result)
	542	dev_err(&urb->dev->dev,
	543	"%s - failed resubmitting read urb, error %d\n",
441b62c1	544	__func__, result);
3fe70ba2 MFN	545	}
	546
	547	return;
	548	}
	549
	550	/* Based on ftdi_sio.c throttle */
95da310e	551	static void aircable_throttle(struct tty_struct *tty)
3fe70ba2	552	{
95da310e	553	struct usb_serial_port *port = tty->driver_data;
3fe70ba2 MFN	554	struct aircable_private *priv = usb_get_serial_port_data(port);
	555	unsigned long flags;
	556
441b62c1	557	dbg("%s - port %d", __func__, port->number);
3fe70ba2 MFN	558
	559	spin_lock_irqsave(&priv->rx_lock, flags);
	560	priv->rx_flags \|= THROTTLED;
	561	spin_unlock_irqrestore(&priv->rx_lock, flags);
	562	}
	563
	564	/* Based on ftdi_sio.c unthrottle */
95da310e	565	static void aircable_unthrottle(struct tty_struct *tty)
3fe70ba2	566	{
95da310e	567	struct usb_serial_port *port = tty->driver_data;
3fe70ba2 MFN	568	struct aircable_private *priv = usb_get_serial_port_data(port);
	569	int actually_throttled;
	570	unsigned long flags;
	571
441b62c1	572	dbg("%s - port %d", __func__, port->number);
3fe70ba2 MFN	573
	574	spin_lock_irqsave(&priv->rx_lock, flags);
	575	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
	576	priv->rx_flags &= ~(THROTTLED \| ACTUALLY_THROTTLED);
	577	spin_unlock_irqrestore(&priv->rx_lock, flags);
	578
	579	if (actually_throttled)
	580	schedule_work(&priv->rx_work);
	581	}
	582
d9b1b787 JH	583	static struct usb_driver aircable_driver = {
	584	.name = "aircable",
	585	.probe = usb_serial_probe,
	586	.disconnect = usb_serial_disconnect,
	587	.id_table = id_table,
	588	.no_dynamic_id = 1,
	589	};
	590
3fe70ba2	591	static struct usb_serial_driver aircable_device = {
52d67f0b JH	592	.driver = {
	593	.owner = THIS_MODULE,
	594	.name = "aircable",
	595	},
d9b1b787	596	.usb_driver = &aircable_driver,
3fe70ba2 MFN	597	.id_table = id_table,
	598	.num_ports = 1,
	599	.attach = aircable_attach,
	600	.probe = aircable_probe,
	601	.shutdown = aircable_shutdown,
	602	.write = aircable_write,
	603	.write_room = aircable_write_room,
	604	.write_bulk_callback = aircable_write_bulk_callback,
	605	.read_bulk_callback = aircable_read_bulk_callback,
	606	.throttle = aircable_throttle,
	607	.unthrottle = aircable_unthrottle,
	608	};
	609
c4d0f8cb	610	static int __init aircable_init(void)
3fe70ba2 MFN	611	{
	612	int retval;
	613	retval = usb_serial_register(&aircable_device);
	614	if (retval)
	615	goto failed_serial_register;
	616	retval = usb_register(&aircable_driver);
	617	if (retval)
	618	goto failed_usb_register;
	619	return 0;
	620
	621	failed_serial_register:
	622	usb_serial_deregister(&aircable_device);
	623	failed_usb_register:
	624	return retval;
	625	}
	626
c4d0f8cb	627	static void __exit aircable_exit(void)
3fe70ba2 MFN	628	{
	629	usb_deregister(&aircable_driver);
	630	usb_serial_deregister(&aircable_device);
	631	}
	632
	633	MODULE_AUTHOR(DRIVER_AUTHOR);
	634	MODULE_DESCRIPTION(DRIVER_DESC);
	635	MODULE_VERSION(DRIVER_VERSION);
	636	MODULE_LICENSE("GPL");
	637
	638	module_init(aircable_init);
	639	module_exit(aircable_exit);
	640
	641	module_param(debug, bool, S_IRUGO \| S_IWUSR);
	642	MODULE_PARM_DESC(debug, "Debug enabled or not");