mct_u232.c

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/*
 * MCT (Magic Control Technology Corp.) USB RS232 Converter Driver
 *
 *   Copyright (C) 2000 Wolfgang Grandegger ([e-mail])
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it 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 program is largely derived from the Belkin USB Serial Adapter Driver
 * (see belkin_sa.[ch]). All of the information about the device was acquired
 * by using SniffUSB on Windows98. For technical details see mct_u232.h.
 *
 * William G. Greathouse and Greg Kroah-Hartman provided great help on how to
 * do the reverse engineering and how to write a USB serial device driver.
 *
 * TO BE DONE, TO BE CHECKED:
 *   DTR/RTS signal handling may be incomplete or incorrect. I have mainly
 *   implemented what I have seen with SniffUSB or found in belkin_sa.c.
 *   For further TODOs check also belkin_sa.c.
 *
 * TEST STATUS:
 *   Basic tests have been performed with minicom/zmodem transfers and
 *   modem dialing under Linux 2.4.0-test10 (for me it works fine).
 *
 * 29-Nov-2000 Greg Kroah-Hartman
 *   - Added device id table to fit with 2.4.0-test11 structure.
 *   - took out DEAL_WITH_TWO_INT_IN_ENDPOINTS #define as it's not needed
 *     (lots of things will change if/when the usb-serial core changes to
 *     handle these issues.
 *
 * 27-Nov-2000 Wolfgang Grandegger
 *   A version for kernel 2.4.0-test10 released to the Linux community 
 *   (via linux-usb-devel).
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/malloc.h>
#include <linux/fcntl.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/tty.h>
#include <linux/module.h>
#include <linux/spinlock.h>

#ifdef CONFIG_USB_SERIAL_DEBUG
 	#define DEBUG
#else
 	#undef DEBUG
#endif
#include <linux/usb.h>

#include "usb-serial.h"
#include "mct_u232.h"


/*
 * Some not properly written applications do not handle the return code of
 * write() correctly. This can result in character losses. A work-a-round
 * can be compiled in with the following definition. This work-a-round
 * should _NOT_ be part of an 'official' kernel release, of course!
 */
#undef FIX_WRITE_RETURN_CODE_PROBLEM
#ifdef FIX_WRITE_RETURN_CODE_PROBLEM
static int write_blocking = 0; /* disabled by default */
#endif

/*
 * Function prototypes
 */
static int  mct_u232_startup	         (struct usb_serial *serial);
static void mct_u232_shutdown	         (struct usb_serial *serial);
static int  mct_u232_open	         (struct usb_serial_port *port,
					  struct file *filp);
static void mct_u232_close	         (struct usb_serial_port *port,
					  struct file *filp);
#ifdef FIX_WRITE_RETURN_CODE_PROBLEM
static int  mct_u232_write	         (struct usb_serial_port *port,
					  int from_user,
					  const unsigned char *buf,
					  int count);
static void mct_u232_write_bulk_callback (struct urb *urb);
#endif
static void mct_u232_read_int_callback   (struct urb *urb);
static void mct_u232_set_termios         (struct usb_serial_port *port,
					  struct termios * old);
static int  mct_u232_ioctl	         (struct usb_serial_port *port,
					  struct file * file,
					  unsigned int cmd,
					  unsigned long arg);
static void mct_u232_break_ctl	         (struct usb_serial_port *port,
					  int break_state );

/*
 * All of the device info needed for the MCT USB-RS232 converter.
 */
static __devinitdata struct usb_device_id id_table [] = {
	{ idVendor: MCT_U232_VID, idProduct: MCT_U232_PID },
	{ }					/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, id_table);


struct usb_serial_device_type mct_u232_device = {
	name:		     "Magic Control Technology USB-RS232",
	id_table:	     id_table,
	needs_interrupt_in:  MUST_HAVE,	 /* 2 interrupt-in endpoints */
	needs_bulk_in:	     MUST_HAVE_NOT,   /* no bulk-in endpoint */
	needs_bulk_out:	     MUST_HAVE,	      /* 1 bulk-out endpoint */
	num_interrupt_in:    2,
	num_bulk_in:	     0,
	num_bulk_out:	     1,
	num_ports:	     1,
	open:		     mct_u232_open,
	close:		     mct_u232_close,
#ifdef FIX_WRITE_RETURN_CODE_PROBLEM
	write:		     mct_u232_write,
	write_bulk_callback: mct_u232_write_bulk_callback,
#endif
	read_int_callback:   mct_u232_read_int_callback,
	ioctl:		     mct_u232_ioctl,
	set_termios:	     mct_u232_set_termios,
	break_ctl:	     mct_u232_break_ctl,
	startup:	     mct_u232_startup,
	shutdown:	     mct_u232_shutdown,
};

struct mct_u232_private {
	unsigned long	     control_state; /* Modem Line Setting (TIOCM) */
	unsigned char        last_lcr;      /* Line Control Register */
	unsigned char	     last_lsr;      /* Line Status Register */
	unsigned char	     last_msr;      /* Modem Status Register */
};

/*
 * Handle vendor specific USB requests
 */

#define WDR_TIMEOUT (HZ * 5 ) /* default urb timeout */

static int mct_u232_set_baud_rate(struct usb_serial *serial, int value)
{
	unsigned int divisor;
        int rc;
	divisor = MCT_U232_BAUD_RATE(value);
        rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                             MCT_U232_SET_BAUD_RATE_REQUEST,
			     MCT_U232_SET_REQUEST_TYPE,
                             0, 0, &divisor, MCT_U232_SET_BAUD_RATE_SIZE,
			     WDR_TIMEOUT);
	if (rc < 0)
		err("Set BAUD RATE %d failed (error = %d)", value, rc);
	dbg("set_baud_rate: 0x%x", divisor);
        return rc;
} /* mct_u232_set_baud_rate */

static int mct_u232_set_line_ctrl(struct usb_serial *serial, unsigned char lcr)
{
        int rc;
        rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                             MCT_U232_SET_LINE_CTRL_REQUEST,
			     MCT_U232_SET_REQUEST_TYPE,
                             0, 0, &lcr, MCT_U232_SET_LINE_CTRL_SIZE,
			     WDR_TIMEOUT);
	if (rc < 0)
		err("Set LINE CTRL 0x%x failed (error = %d)", lcr, rc);
	dbg("set_line_ctrl: 0x%x", lcr);
        return rc;
} /* mct_u232_set_line_ctrl */

static int mct_u232_set_modem_ctrl(struct usb_serial *serial,
				   unsigned long control_state)
{
        int rc;
	unsigned char mcr = MCT_U232_MCR_NONE;

	if (control_state & TIOCM_DTR)
		mcr |= MCT_U232_MCR_DTR;
	if (control_state & TIOCM_RTS)
		mcr |= MCT_U232_MCR_RTS;

        rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                             MCT_U232_SET_MODEM_CTRL_REQUEST,
			     MCT_U232_SET_REQUEST_TYPE,
                             0, 0, &mcr, MCT_U232_SET_MODEM_CTRL_SIZE,
			     WDR_TIMEOUT);
	if (rc < 0)
		err("Set MODEM CTRL 0x%x failed (error = %d)", mcr, rc);
	dbg("set_modem_ctrl: state=0x%lx ==> mcr=0x%x", control_state, mcr);

        return rc;
} /* mct_u232_set_modem_ctrl */

static int mct_u232_get_modem_stat(struct usb_serial *serial, unsigned char *msr)
{
        int rc;
        rc = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
                             MCT_U232_GET_MODEM_STAT_REQUEST,
			     MCT_U232_GET_REQUEST_TYPE,
                             0, 0, msr, MCT_U232_GET_MODEM_STAT_SIZE,
			     WDR_TIMEOUT);
	if (rc < 0) {
		err("Get MODEM STATus failed (error = %d)", rc);
		*msr = 0;
	}
	dbg("get_modem_stat: 0x%x", *msr);
        return rc;
} /* mct_u232_get_modem_stat */

static void mct_u232_msr_to_state(unsigned long *control_state, unsigned char msr)
{
 	/* Translate Control Line states */
	if (msr & MCT_U232_MSR_DSR)
		*control_state |=  TIOCM_DSR;
	else
		*control_state &= ~TIOCM_DSR;
	if (msr & MCT_U232_MSR_CTS)
		*control_state |=  TIOCM_CTS;
	else
		*control_state &= ~TIOCM_CTS;
	if (msr & MCT_U232_MSR_RI)
		*control_state |=  TIOCM_RI;
	else
		*control_state &= ~TIOCM_RI;
	if (msr & MCT_U232_MSR_CD)
		*control_state |=  TIOCM_CD;
	else
		*control_state &= ~TIOCM_CD;
 	dbg("msr_to_state: msr=0x%x ==> state=0x%lx", msr, *control_state);
} /* mct_u232_msr_to_state */

/*
 * Driver's tty interface functions
 */

static int mct_u232_startup (struct usb_serial *serial)
{
	struct mct_u232_private *priv;

	/* allocate the private data structure */
	serial->port->private = kmalloc(sizeof(struct mct_u232_private),
					GFP_KERNEL);
	if (!serial->port->private)
		return (-1); /* error */
	priv = (struct mct_u232_private *)serial->port->private;
	/* set initial values for control structures */
	priv->control_state = 0;
	priv->last_lsr = 0;
	priv->last_msr = 0;

	init_waitqueue_head(&serial->port->write_wait);
	
	return (0);
} /* mct_u232_startup */


static void mct_u232_shutdown (struct usb_serial *serial)
{
	int i;
	
	dbg (__FUNCTION__);

	/* stop reads and writes on all ports */
	for (i=0; i < serial->num_ports; ++i) {
		while (serial->port[i].open_count > 0) {
			mct_u232_close (&serial->port[i], NULL);
		}
		/* My special items, the standard routines free my urbs */
		if (serial->port->private)
			kfree(serial->port->private);
	}
} /* mct_u232_shutdown */

static int  mct_u232_open (struct usb_serial_port *port, struct file *filp)
{
	unsigned long flags;
	struct usb_serial *serial = port->serial;
	struct mct_u232_private *priv = (struct mct_u232_private *)port->private;

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

	spin_lock_irqsave (&port->port_lock, flags);
	
	++port->open_count;
	MOD_INC_USE_COUNT;

	if (!port->active) {
		port->active = 1;

		/* Do a defined restart: the normal serial device seems to 
		 * always turn on DTR and RTS here, so do the same. I'm not
		 * sure if this is really necessary. But it should not harm
		 * either.
		 */
		if (port->tty->termios->c_cflag & CBAUD)
			priv->control_state = TIOCM_DTR | TIOCM_RTS;
		else
			priv->control_state = 0;
		mct_u232_set_modem_ctrl(serial, priv->control_state);
		
		priv->last_lcr = (MCT_U232_DATA_BITS_8 | 
				  MCT_U232_PARITY_NONE |
				  MCT_U232_STOP_BITS_1);
		mct_u232_set_line_ctrl(serial, priv->last_lcr);

		/* Read modem status and update control state */
		mct_u232_get_modem_stat(serial, &priv->last_msr);
		mct_u232_msr_to_state(&priv->control_state, priv->last_msr);

		{
			/* Puh, that's dirty */
			struct usb_serial_port *rport;	
			rport = &serial->port[1];
			rport->tty = port->tty;
			rport->private = port->private;
			port->read_urb = rport->interrupt_in_urb;
		}

		port->read_urb->dev = port->serial->dev;
		if (usb_submit_urb(port->read_urb))
			err("usb_submit_urb(read bulk) failed");

		port->interrupt_in_urb->dev = port->serial->dev;
		if (usb_submit_urb(port->interrupt_in_urb))
			err(" usb_submit_urb(read int) failed");

	}

	spin_unlock_irqrestore (&port->port_lock, flags);
	
	return 0;
} /* mct_u232_open */


static void mct_u232_close (struct usb_serial_port *port, struct file *filp)
{
	unsigned long flags;

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

	spin_lock_irqsave (&port->port_lock, flags);

	--port->open_count;
	MOD_DEC_USE_COUNT;

	if (port->open_count <= 0) {
		/* shutdown our bulk reads and writes */
		usb_unlink_urb (port->write_urb);
		usb_unlink_urb (port->read_urb);
		/* wgg - do I need this? I think so. */
		usb_unlink_urb (port->interrupt_in_urb);
		port->active = 0;
	}
	
	spin_unlock_irqrestore (&port->port_lock, flags);

} /* mct_u232_close */


#ifdef FIX_WRITE_RETURN_CODE_PROBLEM
/* The generic routines work fine otherwise */

static int mct_u232_write (struct usb_serial_port *port, int from_user,
			   const unsigned char *buf, int count)
{
	struct usb_serial *serial = port->serial;
	unsigned long flags;
	int result, bytes_sent, size;

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

	if (count == 0) {
		dbg(__FUNCTION__ " - write request of 0 bytes");
		return (0);
	}

	/* only do something if we have a bulk out endpoint */
	if (!serial->num_bulk_out)
		return(0);;