/*
  Option Card (PCMCIA to) USB to Serial Driver

  Copyright (C) 2005  Matthias Urlichs <smurf@smurf.noris.de>

  This driver is free software; you can redistribute it and/or modify
  it under the terms of Version 2 of the GNU General Public License as
  published by the Free Software Foundation.

  Portions copied from the Keyspan driver by Hugh Blemings <hugh@blemings.org>

  History:

  2005-05-19  v0.1   Initial version, based on incomplete docs
                     and analysis of misbehavior of the standard driver
  2005-05-20  v0.2   Extended the input buffer to avoid losing
                     random 64-byte chunks of data
  2005-05-21  v0.3   implemented chars_in_buffer()
                     turned on low_latency
                     simplified the code somewhat
*/
#define DRIVER_VERSION "v0.3"
#define DRIVER_AUTHOR "Matthias Urlichs <smurf@smurf.noris.de>"
#define DRIVER_DESC "Option Card (PC-Card to) USB to Serial Driver"

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/usb.h>
#include "usb-serial.h"

/* Function prototypes */
static int  option_open (struct usb_serial_port *port, struct file *filp);
static void option_close (struct usb_serial_port *port, struct file *filp);
static int  option_startup (struct usb_serial *serial);
static void option_shutdown (struct usb_serial *serial);
static void option_rx_throttle (struct usb_serial_port *port);
static void option_rx_unthrottle (struct usb_serial_port *port);
static int  option_write_room (struct usb_serial_port *port);

static void option_instat_callback(struct urb *urb, struct pt_regs *regs);


static int  option_write (struct usb_serial_port *port,
                          const unsigned char *buf, int count);

static int  option_chars_in_buffer (struct usb_serial_port *port);
static int  option_ioctl (struct usb_serial_port *port, struct file *file,
                          unsigned int cmd, unsigned long arg);
static void option_set_termios (struct usb_serial_port *port,
                                struct termios *old);
static void option_break_ctl (struct usb_serial_port *port, int break_state);
static int  option_tiocmget (struct usb_serial_port *port, struct file *file);
static int  option_tiocmset (struct usb_serial_port *port, struct file *file,
                             unsigned int set, unsigned int clear);
static int  option_send_setup (struct usb_serial_port *port);

/* Vendor and product IDs */
#define OPTION_VENDOR_ID		0x0AF0

#define	OPTION_PRODUCT_OLD		0x5000
#define	OPTION_PRODUCT_WLAN		0x6000

static struct usb_device_id option_ids[] = {
	{ USB_DEVICE(OPTION_VENDOR_ID, OPTION_PRODUCT_OLD) },
	{ USB_DEVICE(OPTION_VENDOR_ID, OPTION_PRODUCT_WLAN) },
	{ } /* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, option_ids);

static struct usb_driver option_driver = {
	.owner      = THIS_MODULE,
	.name       = "option",
	.probe      = usb_serial_probe,
	.disconnect = usb_serial_disconnect,
	.id_table   = option_ids,
};

/* The card has three separate interfaces, wich the serial driver
 * recognizes separately, thus num_port=1.
 */
static struct usb_serial_device_type option_3port_device = {
	.owner			= THIS_MODULE,
	.name			= "Option 3-port card",
	.short_name		= "option",
	.id_table		= option_ids,
	.num_interrupt_in	= NUM_DONT_CARE,
	.num_bulk_in		= NUM_DONT_CARE,
	.num_bulk_out		= NUM_DONT_CARE,
	.num_ports		= 1, /* 3 */
	.open			= option_open,
	.close			= option_close,
	.write			= option_write,
	.write_room		= option_write_room,
	.chars_in_buffer	= option_chars_in_buffer,
	.throttle		= option_rx_throttle,
	.unthrottle		= option_rx_unthrottle,
	.ioctl			= option_ioctl,
	.set_termios		= option_set_termios,
	.break_ctl		= option_break_ctl,
	.tiocmget		= option_tiocmget,
	.tiocmset		= option_tiocmset,
	.attach			= option_startup,
	.shutdown		= option_shutdown,
	.read_int_callback	= option_instat_callback,
};

static int debug;

/* per port private data */

#define N_IN_URB	4
#define N_OUT_URB	1
#define IN_BUFLEN	1024
#define OUT_BUFLEN	1024

struct option_port_private {
	/* Input endpoints and buffer for this port */
	struct urb	*in_urbs[N_IN_URB];
	char		in_buffer[N_IN_URB][IN_BUFLEN];
	/* Output endpoints and buffer for this port */
	struct urb	*out_urbs[N_OUT_URB];
	char		out_buffer[N_OUT_URB][OUT_BUFLEN];

	/* Settings for the port */
	int		rts_state;	/* Handshaking pins (outputs) */
	int		dtr_state;
	int		cts_state;	/* Handshaking pins (inputs) */
	int		dsr_state;
	int		dcd_state;
	int		ri_state;
	// int		break_on;

	unsigned long	tx_start_time[N_OUT_URB];
};


/* Functions used by new usb-serial code. */
static int __init
option_init (void)
{
	int retval;
	retval = usb_serial_register(&option_3port_device);
	if (retval)
		goto failed_3port_device_register;
	retval = usb_register(&option_driver);
	if (retval)
		goto failed_driver_register;

	info(DRIVER_DESC ": " DRIVER_VERSION);

	return 0;

failed_driver_register:
	usb_serial_deregister (&option_3port_device);
failed_3port_device_register:
	return retval;
}

static void __exit
option_exit (void)
{
	usb_deregister (&option_driver);
	usb_serial_deregister (&option_3port_device);
}

module_init(option_init);
module_exit(option_exit);

static void
option_rx_throttle (struct usb_serial_port *port)
{
	dbg("%s", __FUNCTION__);
}


static void
option_rx_unthrottle (struct usb_serial_port *port)
{
	dbg("%s", __FUNCTION__);
}


static void
option_break_ctl (struct usb_serial_port *port, int break_state)
{
	/* Unfortunately, I don't know how to send a break */
 	dbg("%s", __FUNCTION__);
}


static void
option_set_termios (struct usb_serial_port *port,
				     struct termios *old_termios)
{
	dbg("%s", __FUNCTION__);

	option_send_setup(port);
}

static int
option_tiocmget(struct usb_serial_port *port, struct file *file)
{
	unsigned int			value;
	struct option_port_private 	*portdata;

	portdata = usb_get_serial_port_data(port);

	value = ((portdata->rts_state) ? TIOCM_RTS : 0) |
		((portdata->dtr_state) ? TIOCM_DTR : 0) |
		((portdata->cts_state) ? TIOCM_CTS : 0) |
		((portdata->dsr_state) ? TIOCM_DSR : 0) |
		((portdata->dcd_state) ? TIOCM_CAR : 0) |
		((portdata->ri_state) ? TIOCM_RNG : 0);

	return value;
}

static int
option_tiocmset (struct usb_serial_port *port, struct file *file,
                 unsigned int set, unsigned int clear)
{
	struct option_port_private 	*portdata;

	portdata = usb_get_serial_port_data(port);

	if (set & TIOCM_RTS)
		portdata->rts_state = 1;
	if (set & TIOCM_DTR)
		portdata->dtr_state = 1;

	if (clear & TIOCM_RTS)
		portdata->rts_state = 0;
	if (clear & TIOCM_DTR)
		portdata->dtr_state = 0;
	return option_send_setup(port);
}

static int
option_ioctl (struct usb_serial_port *port, struct file *file,
              unsigned int cmd, unsigned long arg)
{
	return -ENOIOCTLCMD;
}

/* Write */
static int
option_write(struct usb_serial_port *port,
			 const unsigned char *buf, int count)
{
	struct option_port_private 	*portdata;
	int				i;
	int 				left, todo;
	struct urb			*this_urb = NULL; /* spurious */
 	int 				err;

	portdata = usb_get_serial_port_data(port);

	dbg("%s: write (%d chars)", __FUNCTION__, count);

#if 0
	spin_lock(&port->lock);
	if (port->write_urb_busy) {
		spin_unlock(&port->lock);
		dbg("%s: already writing", __FUNCTION__);
		return 0;
	}
	port->write_urb_busy = 1;
	spin_unlock(&port->lock);
#endif

	i = 0;
	left = count;
	while (left>0) {
		todo = left;
		if (todo > OUT_BUFLEN)
			todo = OUT_BUFLEN;

		for (;i < N_OUT_URB; i++) {
			/* Check we have a valid urb/endpoint before we use it... */
			this_urb = portdata->out_urbs[i];
			if (this_urb->status != -EINPROGRESS)
				break;
			if (this_urb->transfer_flags & URB_ASYNC_UNLINK)
				continue;
			if (time_before(jiffies, portdata->tx_start_time[i] + 10 * HZ))
				continue;
			this_urb->transfer_flags |= URB_ASYNC_UNLINK;
			usb_unlink_urb(this_urb);
		}

		if (i == N_OUT_URB) {
			/* no bulk out free! */
			dbg("%s: no output urb -- left %d", __FUNCTION__,count-left);
#if 0
			port->write_urb_busy = 0;
#endif
			return count-left;
		}

		dbg("%s: endpoint %d buf %d", __FUNCTION__, usb_pipeendpoint(this_urb->pipe), i);

		memcpy (this_urb->transfer_buffer, buf, todo);

		/* send the data out the bulk port */
		this_urb->transfer_buffer_length = todo;

		this_urb->transfer_flags &= ~URB_ASYNC_UNLINK;
		this_urb->dev = port->serial->dev;
		err = usb_submit_urb(this_urb, GFP_ATOMIC);
		if (err) {
			dbg("usb_submit_urb %p (write bulk) failed (%d,, has %d)", this_urb, err, this_urb->status);
			continue;
		}
		portdata->tx_start_time[i] = jiffies;
		buf += todo;
		left -= todo;
	}

	count -= left;
#if 0
	port->write_urb_busy = 0;
#endif
	dbg("%s: wrote (did %d)", __FUNCTION__, count);
	return count;
}

static void
option_indat_callback (struct urb *urb, struct pt_regs *regs)
{
	int	i, err;
	int endpoint;
	struct usb_serial_port *port;
	struct tty_struct *tty;
	unsigned char *data = urb->transfer_buffer;

	dbg("%s: %p", __FUNCTION__, urb);

	endpoint = usb_pipeendpoint(urb->pipe);
	port = (struct usb_serial_port *) urb->context;

	if (urb->status) {
		dbg("%s: nonzero status: %d on endpoint %02x.",
		    __FUNCTION__, urb->status, endpoint);
	} else {
		tty = port->tty;
		if (urb->actual_length) {
			for (i = 0; i < urb->actual_length ; ++i) {
				if (tty->flip.count >= TTY_FLIPBUF_SIZE)
					tty_flip_buffer_push(tty);
				tty_insert_flip_char(tty, data[i], 0);
			}
			tty_flip_buffer_push(tty);
		} else {
			dbg("%s: empty read urb received", __FUNCTION__);
		}

		/* Resubmit urb so we continue receiving */
		if (port->open_count && urb->status != -ESHUTDOWN) {
			err = usb_submit_urb(urb, GFP_ATOMIC);
			if (err)
				printk(KERN_ERR "%s: resubmit read urb failed. (%d)", __FUNCTION__, err);
		}
	}
	return;
}

static void
option_outdat_callback (struct urb *urb, struct pt_regs *regs)
{
	struct usb_serial_port *port;

	dbg("%s", __FUNCTION__);

	port = (struct usb_serial_port *) urb->context;

	if (port->open_count)
		schedule_work(&port->work);
}

static void
option_instat_callback (struct urb *urb, struct pt_regs *regs)
{
	int err;
	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
	struct option_port_private *portdata = usb_get_serial_port_data(port);
	struct usb_serial *serial = port->serial;

	dbg("%s", __FUNCTION__);
	dbg("%s: urb %p port %p has data %p", __FUNCTION__,urb,port,portdata);

	if (urb->status == 0) {
		struct usb_ctrlrequest *req_pkt =
				(struct usb_ctrlrequest *)urb->transfer_buffer;

		if (!req_pkt) {
			dbg("%s: NULL req_pkt\n", __FUNCTION__);
			return;
		}
		if ((req_pkt->bRequestType == 0xA1) && (req_pkt->bRequest == 0x20)) {
			int old_dcd_state;
			unsigned char signals = *((unsigned char *)
					urb->transfer_buffer + sizeof(struct usb_ctrlrequest));

			dbg("%s: signal x%x", __FUNCTION__, signals);

			old_dcd_state = portdata->dcd_state;
			portdata->cts_state = 1;
			portdata->dcd_state = ((signals & 0x01) ? 1 : 0);
			portdata->dsr_state = ((signals & 0x02) ? 1 : 0);
			portdata->ri_state = ((signals & 0x08) ? 1 : 0);

			if (port->tty && !C_CLOCAL(port->tty)
					&& old_dcd_state && !portdata->dcd_state) {
				tty_hangup(port->tty);
			}
		} else
			dbg("%s: type %x req %x", __FUNCTION__, req_pkt->bRequestType,req_pkt->bRequest);
	} else
		dbg("%s: error %d", __FUNCTION__, urb->status);

	/* Resubmit urb so we continue receiving IRQ data */
	if (urb->status != -ESHUTDOWN) {
		urb->dev = serial->dev;
		err = usb_submit_urb(urb, GFP_ATOMIC);
		if (err)
			dbg("%s: resubmit intr urb failed. (%d)", __FUNCTION__, err);
	}
}


static int
option_write_room (struct usb_serial_port *port)
{
	struct option_port_private *portdata;
	int i;
	int data_len = 0;
	struct urb *this_urb;

	portdata = usb_get_serial_port_data(port);

	for (i=0; i < N_OUT_URB; i++)
		this_urb = portdata->out_urbs[i];
		if (this_urb && this_urb->status != -EINPROGRESS)
			data_len += OUT_BUFLEN;

	dbg("%s: %d", __FUNCTION__, data_len);
	return data_len;
}


static int
option_chars_in_buffer (struct usb_serial_port *port)
{
	struct option_port_private *portdata;
	int i;
	int data_len = 0;
	struct urb *this_urb;

	portdata = usb_get_serial_port_data(port);

	for (i=0; i < N_OUT_URB; i++)
		this_urb = portdata->out_urbs[i];
		if (this_urb && this_urb->status == -EINPROGRESS)
			data_len += this_urb->transfer_buffer_length;

	dbg("%s: %d", __FUNCTION__, data_len);
	return data_len;
}


static int
option_open (struct usb_serial_port *port, struct file *filp)
{
	struct option_port_private 	*portdata;
	struct usb_serial 		*serial = port->serial;
	int				i, err;
	struct urb			*urb;

	portdata = usb_get_serial_port_data(port);

	dbg("%s", __FUNCTION__);

	/* Set some sane defaults */
	portdata->rts_state = 1;
	portdata->dtr_state = 1;

	/* Reset low level data toggle and start reading from endpoints */
	for (i = 0; i < N_IN_URB; i++) {
		urb = portdata->in_urbs[i];
		if (! urb)
			continue;
		if (urb->dev != serial->dev) {
			dbg("%s: dev %p != %p", __FUNCTION__, urb->dev, serial->dev);
			continue;
		}

		/* make sure endpoint data toggle is synchronized with the device */

		usb_clear_halt(urb->dev, urb->pipe);

		err = usb_submit_urb(urb, GFP_KERNEL);
		if (err) {
			dbg("%s: submit urb %d failed (%d) %d", __FUNCTION__, i, err,
				urb->transfer_buffer_length);
		}
	}

	/* Reset low level data toggle on out endpoints */
	for (i = 0; i < N_OUT_URB; i++) {
		urb = portdata->out_urbs[i];
		if (! urb)
			continue;
		urb->dev = serial->dev;
		/* usb_settoggle(urb->dev, usb_pipeendpoint(urb->pipe), usb_pipeout(urb->pipe), 0); */
	}

	port->tty->low_latency = 1;

	option_send_setup(port);

	return (0);
}

static inline void
stop_urb(struct urb *urb)
{
	if (urb && urb->status == -EINPROGRESS) {
		urb->transfer_flags &= ~URB_ASYNC_UNLINK;
		usb_kill_urb(urb);
	}
}

static void
option_close(struct usb_serial_port *port, struct file *filp)
{
	int			i;
	struct usb_serial	*serial = port->serial;
	struct option_port_private 	*portdata;

	dbg("%s", __FUNCTION__);
	portdata = usb_get_serial_port_data(port);

	portdata->rts_state = 0;
	portdata->dtr_state = 0;

	if (serial->dev) {
		option_send_setup(port);

		/* Stop reading/writing urbs */
		for (i = 0; i < N_IN_URB; i++)
			stop_urb(portdata->in_urbs[i]);
		for (i = 0; i < N_OUT_URB; i++)
			stop_urb(portdata->out_urbs[i]);
	}
	port->tty = NULL;
}


/* Helper functions used by option_setup_urbs */
static struct urb *
option_setup_urb (struct usb_serial *serial, int endpoint,
                  int dir, void *ctx, char *buf, int len,
                  void (*callback)(struct urb *, struct pt_regs *regs))
{
	struct urb *urb;

	if (endpoint == -1)
		return NULL;		/* endpoint not needed */

	urb = usb_alloc_urb(0, GFP_KERNEL);		/* No ISO */
	if (urb == NULL) {
		dbg("%s: alloc for endpoint %d failed.", __FUNCTION__, endpoint);
		return NULL;
	}

		/* Fill URB using supplied data. */
	usb_fill_bulk_urb(urb, serial->dev,
		      usb_sndbulkpipe(serial->dev, endpoint) | dir,
		      buf, len, callback, ctx);

	return urb;
}

/* Setup urbs */
static void
option_setup_urbs(struct usb_serial *serial)
{
	int				j;
	struct usb_serial_port		*port;
	struct option_port_private	*portdata;

	dbg("%s", __FUNCTION__);

	port = serial->port[0];
	portdata = usb_get_serial_port_data(port);

	/* Do indat endpoints first */
	for (j = 0; j <= N_IN_URB; ++j) {
		portdata->in_urbs[j] = option_setup_urb (serial,
                  port->bulk_in_endpointAddress, USB_DIR_IN, port,
                  portdata->in_buffer[j], IN_BUFLEN, option_indat_callback);
	}

	/* outdat endpoints */
	for (j = 0; j <= N_OUT_URB; ++j) {
		portdata->out_urbs[j] = option_setup_urb (serial,
                  port->bulk_out_endpointAddress, USB_DIR_OUT, port,
                  portdata->out_buffer[j], OUT_BUFLEN, option_outdat_callback);
	}
}


static int
option_send_setup(struct usb_serial_port *port)
{
	struct usb_serial *serial = port->serial;
	struct option_port_private *portdata;

	dbg("%s", __FUNCTION__);

	portdata = usb_get_serial_port_data(port);

	if (port->tty) {
		int val = 0;
		if (portdata->dtr_state)
			val |= 0x01;
		if (portdata->rts_state)
			val |= 0x02;

		return usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
					0x22,0x21,val,0,NULL,0,USB_CTRL_SET_TIMEOUT);
	}

	return 0;
}


static int
option_startup (struct usb_serial *serial)
{
	int				i, err;
	struct usb_serial_port		*port;
	struct option_port_private	*portdata;

	dbg("%s", __FUNCTION__);

	/* Now setup per port private data */
	for (i = 0; i < serial->num_ports; i++) {
		port = serial->port[i];
		portdata = kmalloc(sizeof(struct option_port_private), GFP_KERNEL);
		if (!portdata) {
			dbg("%s: kmalloc for option_port_private (%d) failed!.", __FUNCTION__, i);
			return (1);
		}
		memset(portdata, 0, sizeof(struct option_port_private));

		usb_set_serial_port_data(port, portdata);

		if (! port->interrupt_in_urb)
			continue;
		err = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
		if (err)
			dbg("%s: submit irq_in urb failed %d", __FUNCTION__, err);
	}

	option_setup_urbs(serial);

	return (0);
}

static void
option_shutdown (struct usb_serial *serial)
{
	int				i, j;
	struct usb_serial_port		*port;
	struct option_port_private	*portdata;

	dbg("%s", __FUNCTION__);

	/* Stop reading/writing urbs */
	for (i = 0; i < serial->num_ports; ++i) {
		port = serial->port[i];
		portdata = usb_get_serial_port_data(port);
		for (j = 0; j < N_IN_URB; j++)
			stop_urb(portdata->in_urbs[j]);
		for (j = 0; j < N_OUT_URB; j++)
			stop_urb(portdata->out_urbs[j]);
	}

	/* Now free them */
	for (i = 0; i < serial->num_ports; ++i) {
		port = serial->port[i];
		portdata = usb_get_serial_port_data(port);

		for (j = 0; j < N_IN_URB; j++) {
			if (portdata->in_urbs[j]) {
				usb_free_urb(portdata->in_urbs[j]);
				portdata->in_urbs[j] = NULL;
			}
		}
		for (j = 0; j < N_OUT_URB; j++) {
			if (portdata->out_urbs[j]) {
				usb_free_urb(portdata->out_urbs[j]);
				portdata->out_urbs[j] = NULL;
			}
		}
	}

	/* Now free per port private data */
	for (i = 0; i < serial->num_ports; i++) {
		port = serial->port[i];
		kfree(usb_get_serial_port_data(port));
	}
}

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

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug messages");