text: /*****************************************************************************
  *
  * Filename:      stir4200.c
  * Version:       0.4
  * Description:   Irda SigmaTel USB Dongle
  * Status:        Experimental
  * Author:        Stephen Hemminger <shemminger@osdl.org>
  *
  *  	Based on earlier driver by Paul Stewart <stewart@parc.com>
  *
  *	Copyright (C) 2000, Roman Weissgaerber <weissg@vienna.at>
  *	Copyright (C) 2001, Dag Brattli <dag@brattli.net>
  *	Copyright (C) 2001, Jean Tourrilhes <jt@hpl.hp.com>
  *	Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
  *
  *	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.
  *
  *	This program is distributed in the hope that it will be useful,
  *	but WITHOUT ANY WARRANTY; without even the implied warranty of
  *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *	GNU General Public License for more details.
  *
  *	You should have received a copy of the GNU General Public License
  *	along with this program; if not, write to the Free Software
  *	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  *
  *****************************************************************************/
  
  /*
   * This dongle does no framing, and requires polling to receive the
   * data.  The STIr4200 has bulk in and out endpoints just like
   * usr-irda devices, but the data it sends and receives is raw; like
   * irtty, it needs to call the wrap and unwrap functions to add and
   * remove SOF/BOF and escape characters to/from the frame.
   */
  
  #include <linux/module.h>
  #include <linux/moduleparam.h>
  
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/init.h>
  #include <linux/time.h>
  #include <linux/skbuff.h>
  #include <linux/netdevice.h>
  #include <linux/slab.h>
  #include <linux/delay.h>
  #include <linux/usb.h>
  #include <linux/crc32.h>
  #include <linux/kthread.h>
  #include <linux/freezer.h>
  #include <net/irda/irda.h>
  #include <net/irda/irda_device.h>
  #include <net/irda/wrapper.h>
  #include <net/irda/crc.h>
  #include <asm/byteorder.h>
  #include <asm/unaligned.h>
  
  MODULE_AUTHOR("Stephen Hemminger <shemminger@linux-foundation.org>");
  MODULE_DESCRIPTION("IrDA-USB Dongle Driver for SigmaTel STIr4200");
  MODULE_LICENSE("GPL");
  
  static int qos_mtt_bits = 0x07;	/* 1 ms or more */
  module_param(qos_mtt_bits, int, 0);
  MODULE_PARM_DESC(qos_mtt_bits, "Minimum Turn Time");
  
  static int rx_sensitivity = 1;	/* FIR 0..4, SIR 0..6 */
  module_param(rx_sensitivity, int, 0);
  MODULE_PARM_DESC(rx_sensitivity, "Set Receiver sensitivity (0-6, 0 is most sensitive)");
  
  static int tx_power = 0;	/* 0 = highest ... 3 = lowest */
  module_param(tx_power, int, 0);
  MODULE_PARM_DESC(tx_power, "Set Transmitter power (0-3, 0 is highest power)");
  
  #define STIR_IRDA_HEADER  	4
  #define CTRL_TIMEOUT		100	   /* milliseconds */
  #define TRANSMIT_TIMEOUT	200	   /* milliseconds */
  #define STIR_FIFO_SIZE		4096
  #define FIFO_REGS_SIZE		3
  
  enum FirChars {
  	FIR_CE   = 0x7d,
  	FIR_XBOF = 0x7f,
  	FIR_EOF  = 0x7e,
  };
  
  enum StirRequests {
  	REQ_WRITE_REG =		0x00,
  	REQ_READ_REG =		0x01,
  	REQ_READ_ROM =		0x02,
  	REQ_WRITE_SINGLE =	0x03,
  };
  
  /* Register offsets */
  enum StirRegs {
  	REG_RSVD=0,
  	REG_MODE,
  	REG_PDCLK,
  	REG_CTRL1,
  	REG_CTRL2,
  	REG_FIFOCTL,
  	REG_FIFOLSB,
  	REG_FIFOMSB,
  	REG_DPLL,
  	REG_IRDIG,
  	REG_TEST=15,
  };
  
  enum StirModeMask {
  	MODE_FIR = 0x80,
  	MODE_SIR = 0x20,
  	MODE_ASK = 0x10,
  	MODE_FASTRX = 0x08,
  	MODE_FFRSTEN = 0x04,
  	MODE_NRESET = 0x02,
  	MODE_2400 = 0x01,
  };
  
  enum StirPdclkMask {
  	PDCLK_4000000 = 0x02,
  	PDCLK_115200 = 0x09,
  	PDCLK_57600 = 0x13,
  	PDCLK_38400 = 0x1D,
  	PDCLK_19200 = 0x3B,
  	PDCLK_9600 = 0x77,
  	PDCLK_2400 = 0xDF,
  };
  
  enum StirCtrl1Mask {
  	CTRL1_SDMODE = 0x80,
  	CTRL1_RXSLOW = 0x40,
  	CTRL1_TXPWD = 0x10,
  	CTRL1_RXPWD = 0x08,
  	CTRL1_SRESET = 0x01,
  };
  
  enum StirCtrl2Mask {
  	CTRL2_SPWIDTH = 0x08,
  	CTRL2_REVID = 0x03,
  };
  
  enum StirFifoCtlMask {
  	FIFOCTL_DIR = 0x10,
  	FIFOCTL_CLR = 0x08,
  	FIFOCTL_EMPTY = 0x04,
  };
  
  enum StirDiagMask {
  	IRDIG_RXHIGH = 0x80,
  	IRDIG_RXLOW = 0x40,
  };
  
  enum StirTestMask {
  	TEST_PLLDOWN = 0x80,
  	TEST_LOOPIR = 0x40,
  	TEST_LOOPUSB = 0x20,
  	TEST_TSTENA = 0x10,
  	TEST_TSTOSC = 0x0F,
  };
  
  struct stir_cb {
          struct usb_device *usbdev;      /* init: probe_irda */
          struct net_device *netdev;      /* network layer */
          struct irlap_cb   *irlap;       /* The link layer we are binded to */
  
          struct qos_info   qos;
  	unsigned 	  speed;	/* Current speed */
  
          struct task_struct *thread;     /* transmit thread */
  
  	struct sk_buff	  *tx_pending;
  	void		  *io_buf;	/* transmit/receive buffer */
  	__u8		  *fifo_status;
  
  	iobuff_t  	  rx_buff;	/* receive unwrap state machine */
  	struct timeval	  rx_time;
  	int		  receiving;
  	struct urb	 *rx_urb;
  };
  
  
  /* These are the currently known USB ids */
  static struct usb_device_id dongles[] = {
      /* SigmaTel, Inc,  STIr4200 IrDA/USB Bridge */
      { USB_DEVICE(0x066f, 0x4200) },
      { }
  };
  
  MODULE_DEVICE_TABLE(usb, dongles);
  
  /* Send control message to set dongle register */
  static int write_reg(struct stir_cb *stir, __u16 reg, __u8 value)
  {
  	struct usb_device *dev = stir->usbdev;
  
  	pr_debug("%s: write reg %d = 0x%x\n",
  		 stir->netdev->name, reg, value);
  	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
  			       REQ_WRITE_SINGLE,
  			       USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_DEVICE,
  			       value, reg, NULL, 0,
  			       CTRL_TIMEOUT);
  }
  
  /* Send control message to read multiple registers */
  static inline int read_reg(struct stir_cb *stir, __u16 reg,
  		    __u8 *data, __u16 count)
  {
  	struct usb_device *dev = stir->usbdev;
  
  	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
  			       REQ_READ_REG,
  			       USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
  			       0, reg, data, count,
  			       CTRL_TIMEOUT);
  }
  
  static inline int isfir(u32 speed)
  {
  	return speed == 4000000;
  }
  
  /*
   * Prepare a FIR IrDA frame for transmission to the USB dongle.  The
   * FIR transmit frame is documented in the datasheet.  It consists of
   * a two byte 0x55 0xAA sequence, two little-endian length bytes, a
   * sequence of exactly 16 XBOF bytes of 0x7E, two BOF bytes of 0x7E,
   * then the data escaped as follows:
   *
   *    0x7D -> 0x7D 0x5D
   *    0x7E -> 0x7D 0x5E
   *    0x7F -> 0x7D 0x5F
   *
   * Then, 4 bytes of little endian (stuffed) FCS follow, then two
   * trailing EOF bytes of 0x7E.
   */
  static inline __u8 *stuff_fir(__u8 *p, __u8 c)
  {
  	switch(c) {
  	case 0x7d:
  	case 0x7e:
  	case 0x7f:
  		*p++ = 0x7d;
  		c ^= IRDA_TRANS;
  		/* fall through */
  	default:
  		*p++ = c;
  	}
  	return p;
  }
  
  /* Take raw data in skb and put it wrapped into buf */
  static unsigned wrap_fir_skb(const struct sk_buff *skb, __u8 *buf)
  {
  	__u8 *ptr = buf;
  	__u32 fcs = ~(crc32_le(~0, skb->data, skb->len));
  	__u16 wraplen;
  	int i;
  
  	/* Header */
  	buf[0] = 0x55;
  	buf[1] = 0xAA;
  
  	ptr = buf + STIR_IRDA_HEADER;
  	memset(ptr, 0x7f, 16);
  	ptr += 16;
  
  	/* BOF */
  	*ptr++  = 0x7e;
  	*ptr++  = 0x7e;
  
  	/* Address / Control / Information */
  	for (i = 0; i < skb->len; i++)
  		ptr = stuff_fir(ptr, skb->data[i]);
  
  	/* FCS */
  	ptr = stuff_fir(ptr, fcs & 0xff);
  	ptr = stuff_fir(ptr, (fcs >> 8) & 0xff);
  	ptr = stuff_fir(ptr, (fcs >> 16) & 0xff);
  	ptr = stuff_fir(ptr, (fcs >> 24) & 0xff);
  
  	/* EOFs */
  	*ptr++ = 0x7e;
  	*ptr++ = 0x7e;
  
  	/* Total length, minus the header */
  	wraplen = (ptr - buf) - STIR_IRDA_HEADER;
  	buf[2] = wraplen & 0xff;
  	buf[3] = (wraplen >> 8) & 0xff;
  
  	return wraplen + STIR_IRDA_HEADER;
  }
  
  static unsigned wrap_sir_skb(struct sk_buff *skb, __u8 *buf)
  {
  	__u16 wraplen;
  
  	wraplen = async_wrap_skb(skb, buf + STIR_IRDA_HEADER,
  				 STIR_FIFO_SIZE - STIR_IRDA_HEADER);
  	buf[0] = 0x55;
  	buf[1] = 0xAA;
  	buf[2] = wraplen & 0xff;
  	buf[3] = (wraplen >> 8) & 0xff;
  
  	return wraplen + STIR_IRDA_HEADER;
  }
  
  /*
   * Frame is fully formed in the rx_buff so check crc
   * and pass up to irlap
   * setup for next receive
   */
  static void fir_eof(struct stir_cb *stir)
  {
  	iobuff_t *rx_buff = &stir->rx_buff;
  	int len = rx_buff->len - 4;
  	struct sk_buff *skb, *nskb;
  	__u32 fcs;
  
  	if (unlikely(len <= 0)) {
  		pr_debug("%s: short frame len %d\n",
  			 stir->netdev->name, len);
  
  		++stir->netdev->stats.rx_errors;
  		++stir->netdev->stats.rx_length_errors;
  		return;
  	}
  
  	fcs = ~(crc32_le(~0, rx_buff->data, len));
  	if (fcs != get_unaligned_le32(rx_buff->data + len)) {
  		pr_debug("crc error calc 0x%x len %d\n", fcs, len);
  		stir->netdev->stats.rx_errors++;
  		stir->netdev->stats.rx_crc_errors++;
  		return;
  	}
  
  	/* if frame is short then just copy it */
  	if (len < IRDA_RX_COPY_THRESHOLD) {
  		nskb = dev_alloc_skb(len + 1);
  		if (unlikely(!nskb)) {
  			++stir->netdev->stats.rx_dropped;
  			return;
  		}
  		skb_reserve(nskb, 1);
  		skb = nskb;
  		skb_copy_to_linear_data(nskb, rx_buff->data, len);
  	} else {
  		nskb = dev_alloc_skb(rx_buff->truesize);
  		if (unlikely(!nskb)) {
  			++stir->netdev->stats.rx_dropped;
  			return;
  		}
  		skb_reserve(nskb, 1);
  		skb = rx_buff->skb;
  		rx_buff->skb = nskb;
  		rx_buff->head = nskb->data;
  	}
  
  	skb_put(skb, len);
  
  	skb_reset_mac_header(skb);
  	skb->protocol = htons(ETH_P_IRDA);
  	skb->dev = stir->netdev;
  
  	netif_rx(skb);
  
  	stir->netdev->stats.rx_packets++;
  	stir->netdev->stats.rx_bytes += len;
  
  	rx_buff->data = rx_buff->head;
  	rx_buff->len = 0;
  }
  
  /* Unwrap FIR stuffed data and bump it to IrLAP */
  static void stir_fir_chars(struct stir_cb *stir,
  			    const __u8 *bytes, int len)
  {
  	iobuff_t *rx_buff = &stir->rx_buff;
  	int	i;
  
  	for (i = 0; i < len; i++) {
  		__u8	byte = bytes[i];
  
  		switch(rx_buff->state) {
  		case OUTSIDE_FRAME:
  			/* ignore garbage till start of frame */
  			if (unlikely(byte != FIR_EOF))
  				continue;
  			/* Now receiving frame */
  			rx_buff->state = BEGIN_FRAME;
  
  			/* Time to initialize receive buffer */
  			rx_buff->data = rx_buff->head;
  			rx_buff->len = 0;
  			continue;
  
  		case LINK_ESCAPE:
  			if (byte == FIR_EOF) {
  				pr_debug("%s: got EOF after escape\n",
  					 stir->netdev->name);
  				goto frame_error;
  			}
  			rx_buff->state = INSIDE_FRAME;
  			byte ^= IRDA_TRANS;
  			break;
  
  		case BEGIN_FRAME:
  			/* ignore multiple BOF/EOF */
  			if (byte == FIR_EOF)
  				continue;
  			rx_buff->state = INSIDE_FRAME;
  			rx_buff->in_frame = TRUE;
  
  			/* fall through */
  		case INSIDE_FRAME:
  			switch(byte) {
  			case FIR_CE:
  				rx_buff->state = LINK_ESCAPE;
  				continue;
  			case FIR_XBOF:
  				/* 0x7f is not used in this framing */
  				pr_debug("%s: got XBOF without escape\n",
  					 stir->netdev->name);
  				goto frame_error;
  			case FIR_EOF:
  				rx_buff->state = OUTSIDE_FRAME;
  				rx_buff->in_frame = FALSE;
  				fir_eof(stir);
  				continue;
  			}
  			break;
  		}
  
  		/* add byte to rx buffer */
  		if (unlikely(rx_buff->len >= rx_buff->truesize)) {
  			pr_debug("%s: fir frame exceeds %d\n",
  				 stir->netdev->name, rx_buff->truesize);
  			++stir->netdev->stats.rx_over_errors;
  			goto error_recovery;
  		}
  
  		rx_buff->data[rx_buff->len++] = byte;
  		continue;
  
  	frame_error:
  		++stir->netdev->stats.rx_frame_errors;
  
  	error_recovery:
  		++stir->netdev->stats.rx_errors;
  		rx_buff->state = OUTSIDE_FRAME;
  		rx_buff->in_frame = FALSE;
  	}
  }
  
  /* Unwrap SIR stuffed data and bump it up to IrLAP */
  static void stir_sir_chars(struct stir_cb *stir,
  			    const __u8 *bytes, int len)
  {
  	int i;
  
  	for (i = 0; i < len; i++)
  		async_unwrap_char(stir->netdev, &stir->netdev->stats,
  				  &stir->rx_buff, bytes[i]);
  }
  
  static inline void unwrap_chars(struct stir_cb *stir,
  				const __u8 *bytes, int length)
  {
  	if (isfir(stir->speed))
  		stir_fir_chars(stir, bytes, length);
  	else
  		stir_sir_chars(stir, bytes, length);
  }
  
  /* Mode parameters for each speed */
  static const struct {
  	unsigned speed;
  	__u8 pdclk;
  } stir_modes[] = {
          { 2400,    PDCLK_2400 },
          { 9600,    PDCLK_9600 },
          { 19200,   PDCLK_19200 },
          { 38400,   PDCLK_38400 },
          { 57600,   PDCLK_57600 },
          { 115200,  PDCLK_115200 },
          { 4000000, PDCLK_4000000 },
  };
  
  
  /*
   * Setup chip for speed.
   *  Called at startup to initialize the chip
   *  and on speed changes.
   *
   * Note: Write multiple registers doesn't appear to work
   */
  static int change_speed(struct stir_cb *stir, unsigned speed)
  {
  	int i, err;
  	__u8 mode;
  
  	for (i = 0; i < ARRAY_SIZE(stir_modes); ++i) {
  		if (speed == stir_modes[i].speed)
  			goto found;
  	}
  
  	dev_warn(&stir->netdev->dev, "invalid speed %d\n", speed);
  	return -EINVAL;
  
   found:
  	pr_debug("speed change from %d to %d\n", stir->speed, speed);
  
  	/* Reset modulator */
  	err = write_reg(stir, REG_CTRL1, CTRL1_SRESET);
  	if (err)
  		goto out;
  
  	/* Undocumented magic to tweak the DPLL */
  	err = write_reg(stir, REG_DPLL, 0x15);
  	if (err)
  		goto out;
  
  	/* Set clock */
  	err = write_reg(stir, REG_PDCLK, stir_modes[i].pdclk);
  	if (err)
  		goto out;
  
  	mode = MODE_NRESET | MODE_FASTRX;
  	if (isfir(speed))
  		mode |= MODE_FIR | MODE_FFRSTEN;
  	else
  		mode |= MODE_SIR;
  
  	if (speed == 2400)
  		mode |= MODE_2400;
  
  	err = write_reg(stir, REG_MODE, mode);
  	if (err)
  		goto out;
  
  	/* This resets TEMIC style transceiver if any. */
  	err = write_reg(stir, REG_CTRL1,
  			CTRL1_SDMODE | (tx_power & 3) << 1);
  	if (err)
  		goto out;
  
  	err = write_reg(stir, REG_CTRL1, (tx_power & 3) << 1);
  	if (err)
  		goto out;
  
  	/* Reset sensitivity */
  	err = write_reg(stir, REG_CTRL2, (rx_sensitivity & 7) << 5);
   out:
  	stir->speed = speed;
  	return err;
  }
  
  /*
   * Called from net/core when new frame is available.
   */
  static netdev_tx_t stir_hard_xmit(struct sk_buff *skb,
  					struct net_device *netdev)
  {
  	struct stir_cb *stir = netdev_priv(netdev);
  
  	netif_stop_queue(netdev);
  
  	/* the IRDA wrapping routines don't deal with non linear skb */
  	SKB_LINEAR_ASSERT(skb);
  
  	skb = xchg(&stir->tx_pending, skb);
          wake_up_process(stir->thread);
  	
  	/* this should never happen unless stop/wakeup problem */
  	if (unlikely(skb)) {
  		WARN_ON(1);
  		dev_kfree_skb(skb);
  	}
  
  	return NETDEV_TX_OK;
  }
  
  /*
   * Wait for the transmit FIFO to have space for next data
   *
   * If space < 0 then wait till FIFO completely drains.
   * FYI: can take up to 13 seconds at 2400baud.
   */
  static int fifo_txwait(struct stir_cb *stir, int space)
  {
  	int err;
  	unsigned long count, status;
  	unsigned long prev_count = 0x1fff;
  
  	/* Read FIFO status and count */
  	for (;; prev_count = count) {
  		err = read_reg(stir, REG_FIFOCTL, stir->fifo_status, 
  				   FIFO_REGS_SIZE);
  		if (unlikely(err != FIFO_REGS_SIZE)) {
  			dev_warn(&stir->netdev->dev,
  				 "FIFO register read error: %d\n", err);
  
  			return err;
  		}
  
  		status = stir->fifo_status[0];
  		count = (unsigned)(stir->fifo_status[2] & 0x1f) << 8 
  			| stir->fifo_status[1];
  
  		pr_debug("fifo status 0x%lx count %lu\n", status, count);
  
  		/* is fifo receiving already, or empty */
  		if (!(status & FIFOCTL_DIR) ||
  		    (status & FIFOCTL_EMPTY))
  			return 0;
  
  		if (signal_pending(current))
  			return -EINTR;
  
  		/* shutting down? */
  		if (!netif_running(stir->netdev) ||
  		    !netif_device_present(stir->netdev))
  			return -ESHUTDOWN;
  
  		/* only waiting for some space */
  		if (space >= 0 && STIR_FIFO_SIZE - 4 > space + count)
  			return 0;
  
  		/* queue confused */
  		if (prev_count < count)
  			break;
  
  		/* estimate transfer time for remaining chars */
  		msleep((count * 8000) / stir->speed);
  	}
  			
  	err = write_reg(stir, REG_FIFOCTL, FIFOCTL_CLR);
  	if (err) 
  		return err;
  	err = write_reg(stir, REG_FIFOCTL, 0);
  	if (err)
  		return err;
  
  	return 0;
  }
  
  
  /* Wait for turnaround delay before starting transmit.  */
  static void turnaround_delay(const struct stir_cb *stir, long us)
  {
  	long ticks;
  	struct timeval now;
  
  	if (us <= 0)
  		return;
  
  	do_gettimeofday(&now);
  	if (now.tv_sec - stir->rx_time.tv_sec > 0)
  		us -= USEC_PER_SEC;
  	us -= now.tv_usec - stir->rx_time.tv_usec;
  	if (us < 10)
  		return;
  
  	ticks = us / (1000000 / HZ);
  	if (ticks > 0)
  		schedule_timeout_interruptible(1 + ticks);
  	else
  		udelay(us);
  }
  
  /*
   * Start receiver by submitting a request to the receive pipe.
   * If nothing is available it will return after rx_interval.
   */
  static int receive_start(struct stir_cb *stir)
  {
  	/* reset state */
  	stir->receiving = 1;
  
  	stir->rx_buff.in_frame = FALSE;
  	stir->rx_buff.state = OUTSIDE_FRAME;
  
  	stir->rx_urb->status = 0;
  	return usb_submit_urb(stir->rx_urb, GFP_KERNEL);
  }
  
  /* Stop all pending receive Urb's */
  static void receive_stop(struct stir_cb *stir)
  {
  	stir->receiving = 0;
  	usb_kill_urb(stir->rx_urb);
  
  	if (stir->rx_buff.in_frame) 
  		stir->netdev->stats.collisions++;
  }
  /*
   * Wrap data in socket buffer and send it.
   */
  static void stir_send(struct stir_cb *stir, struct sk_buff *skb)
  {
  	unsigned wraplen;
  	int first_frame = 0;
  
  	/* if receiving, need to turnaround */
  	if (stir->receiving) {
  		receive_stop(stir);
  		turnaround_delay(stir, irda_get_mtt(skb));
  		first_frame = 1;
  	}
  
  	if (isfir(stir->speed))
  		wraplen = wrap_fir_skb(skb, stir->io_buf);
  	else
  		wraplen = wrap_sir_skb(skb, stir->io_buf);
  		
  	/* check for space available in fifo */
  	if (!first_frame)
  		fifo_txwait(stir, wraplen);
  
  	stir->netdev->stats.tx_packets++;
  	stir->netdev->stats.tx_bytes += skb->len;
  	stir->netdev->trans_start = jiffies;
  	pr_debug("send %d (%d)\n", skb->len, wraplen);
  
  	if (usb_bulk_msg(stir->usbdev, usb_sndbulkpipe(stir->usbdev, 1),
  			 stir->io_buf, wraplen,
  			 NULL, TRANSMIT_TIMEOUT))
  		stir->netdev->stats.tx_errors++;
  }
  
  /*
   * Transmit state machine thread
   */
  static int stir_transmit_thread(void *arg)
  {
  	struct stir_cb *stir = arg;
  	struct net_device *dev = stir->netdev;
  	struct sk_buff *skb;
  
          while (!kthread_should_stop()) {
  #ifdef CONFIG_PM
  		/* if suspending, then power off and wait */
  		if (unlikely(freezing(current))) {
  			if (stir->receiving)
  				receive_stop(stir);
  			else
  				fifo_txwait(stir, -1);
  
  			write_reg(stir, REG_CTRL1, CTRL1_TXPWD|CTRL1_RXPWD);
  
  			try_to_freeze();
  
  			if (change_speed(stir, stir->speed))
  				break;
  		}
  #endif
  
  		/* if something to send? */
  		skb = xchg(&stir->tx_pending, NULL);
  		if (skb) {
  			unsigned new_speed = irda_get_next_speed(skb);
  			netif_wake_queue(dev);
  
  			if (skb->len > 0)
  				stir_send(stir, skb);
  			dev_kfree_skb(skb);
  
  			if ((new_speed != -1) && (stir->speed != new_speed)) {
  				if (fifo_txwait(stir, -1) ||
  				    change_speed(stir, new_speed))
  					break;
  			}
  			continue;
  		}
  
  		/* nothing to send? start receiving */
  		if (!stir->receiving &&
  		    irda_device_txqueue_empty(dev)) {
  			/* Wait otherwise chip gets confused. */
  			if (fifo_txwait(stir, -1))
  				break;
  
  			if (unlikely(receive_start(stir))) {
  				if (net_ratelimit())
  					dev_info(&dev->dev,
  						 "%s: receive usb submit failed\n",
  						 stir->netdev->name);
  				stir->receiving = 0;
  				msleep(10);
  				continue;
  			}
  		}
  
  		/* sleep if nothing to send */
                  set_current_state(TASK_INTERRUPTIBLE);
                  schedule();
  
  	}
          return 0;
  }
  
  
  /*
   * USB bulk receive completion callback.
   * Wakes up every ms (usb round trip) with wrapped 
   * data.
   */
  static void stir_rcv_irq(struct urb *urb)
  {
  	struct stir_cb *stir = urb->context;
  	int err;
  
  	/* in process of stopping, just drop data */
  	if (!netif_running(stir->netdev))
  		return;
  
  	/* unlink, shutdown, unplug, other nasties */
  	if (urb->status != 0) 
  		return;
  
  	if (urb->actual_length > 0) {
  		pr_debug("receive %d\n", urb->actual_length);
  		unwrap_chars(stir, urb->transfer_buffer,
  			     urb->actual_length);
  		
  		do_gettimeofday(&stir->rx_time);
  	}
  
  	/* kernel thread is stopping receiver don't resubmit */
  	if (!stir->receiving)
  		return;
  
  	/* resubmit existing urb */
  	err = usb_submit_urb(urb, GFP_ATOMIC);
  
  	/* in case of error, the kernel thread will restart us */
  	if (err) {
  		dev_warn(&stir->netdev->dev, "usb receive submit error: %d\n",
  			 err);
  		stir->receiving = 0;
  		wake_up_process(stir->thread);
  	}
  }
  
  /*
   * Function stir_net_open (dev)
   *
   *    Network device is taken up. Usually this is done by "ifconfig irda0 up"
   */
  static int stir_net_open(struct net_device *netdev)
  {
  	struct stir_cb *stir = netdev_priv(netdev);
  	int err;
  	char hwname[16];
  
  	err = usb_clear_halt(stir->usbdev, usb_sndbulkpipe(stir->usbdev, 1));
  	if (err)
  		goto err_out1;
  	err = usb_clear_halt(stir->usbdev, usb_rcvbulkpipe(stir->usbdev, 2));
  	if (err)
  		goto err_out1;
  
  	err = change_speed(stir, 9600);
  	if (err)
  		goto err_out1;
  
  	err = -ENOMEM;
  
  	/* Initialize for SIR/FIR to copy data directly into skb.  */
  	stir->receiving = 0;
  	stir->rx_buff.truesize = IRDA_SKB_MAX_MTU;
  	stir->rx_buff.skb = dev_alloc_skb(IRDA_SKB_MAX_MTU);
  	if (!stir->rx_buff.skb) 
  		goto err_out1;
  
  	skb_reserve(stir->rx_buff.skb, 1);
  	stir->rx_buff.head = stir->rx_buff.skb->data;
  	do_gettimeofday(&stir->rx_time);
  
  	stir->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
  	if (!stir->rx_urb) 
  		goto err_out2;
  
  	stir->io_buf = kmalloc(STIR_FIFO_SIZE, GFP_KERNEL);
  	if (!stir->io_buf)
  		goto err_out3;
  
  	usb_fill_bulk_urb(stir->rx_urb, stir->usbdev,
  			  usb_rcvbulkpipe(stir->usbdev, 2),
  			  stir->io_buf, STIR_FIFO_SIZE,
  			  stir_rcv_irq, stir);
  
  	stir->fifo_status = kmalloc(FIFO_REGS_SIZE, GFP_KERNEL);
  	if (!stir->fifo_status) 
  		goto err_out4;
  		
  	/*
  	 * Now that everything should be initialized properly,
  	 * Open new IrLAP layer instance to take care of us...
  	 * Note : will send immediately a speed change...
  	 */
  	sprintf(hwname, "usb#%d", stir->usbdev->devnum);
  	stir->irlap = irlap_open(netdev, &stir->qos, hwname);
  	if (!stir->irlap) {
  		err("stir4200: irlap_open failed");
  		goto err_out5;
  	}
  
  	/** Start kernel thread for transmit.  */
  	stir->thread = kthread_run(stir_transmit_thread, stir,
  				   "%s", stir->netdev->name);
          if (IS_ERR(stir->thread)) {
                  err = PTR_ERR(stir->thread);
  		err("stir4200: unable to start kernel thread");
  		goto err_out6;
  	}
  
  	netif_start_queue(netdev);
  
  	return 0;
  
   err_out6:
  	irlap_close(stir->irlap);
   err_out5:
  	kfree(stir->fifo_status);
   err_out4:
  	kfree(stir->io_buf);
   err_out3:
  	usb_free_urb(stir->rx_urb);
   err_out2:
  	kfree_skb(stir->rx_buff.skb);
   err_out1:
  	return err;
  }
  
  /*
   * Function stir_net_close (stir)
   *
   *    Network device is taken down. Usually this is done by
   *    "ifconfig irda0 down"
   */
  static int stir_net_close(struct net_device *netdev)
  {
  	struct stir_cb *stir = netdev_priv(netdev);
  
  	/* Stop transmit processing */
  	netif_stop_queue(netdev);
  
  	/* Kill transmit thread */
  	kthread_stop(stir->thread);
  	kfree(stir->fifo_status);
  
  	/* Mop up receive urb's */
  	usb_kill_urb(stir->rx_urb);
  	
  	kfree(stir->io_buf);
  	usb_free_urb(stir->rx_urb);
  	kfree_skb(stir->rx_buff.skb);
  
  	/* Stop and remove instance of IrLAP */
  	if (stir->irlap)
  		irlap_close(stir->irlap);
  
  	stir->irlap = NULL;
  
  	return 0;
  }
  
  /*
   * IOCTLs : Extra out-of-band network commands...
   */
  static int stir_net_ioctl(struct net_device *netdev, struct ifreq *rq, int cmd)
  {
  	struct if_irda_req *irq = (struct if_irda_req *) rq;
  	struct stir_cb *stir = netdev_priv(netdev);
  	int ret = 0;
  
  	switch (cmd) {
  	case SIOCSBANDWIDTH: /* Set bandwidth */
  		if (!capable(CAP_NET_ADMIN))
  			return -EPERM;
  
  		/* Check if the device is still there */
  		if (netif_device_present(stir->netdev))
  			ret = change_speed(stir, irq->ifr_baudrate);
  		break;
  
  	case SIOCSMEDIABUSY: /* Set media busy */
  		if (!capable(CAP_NET_ADMIN))
  			return -EPERM;
  
  		/* Check if the IrDA stack is still there */
  		if (netif_running(stir->netdev))
  			irda_device_set_media_busy(stir->netdev, TRUE);
  		break;
  
  	case SIOCGRECEIVING:
  		/* Only approximately true */
  		irq->ifr_receiving = stir->receiving;
  		break;
  
  	default:
  		ret = -EOPNOTSUPP;
  	}
  
  	return ret;
  }
  
  static const struct net_device_ops stir_netdev_ops = {
  	.ndo_open       = stir_net_open,
  	.ndo_stop       = stir_net_close,
  	.ndo_start_xmit = stir_hard_xmit,
  	.ndo_do_ioctl   = stir_net_ioctl,
  };
  
  /*
   * This routine is called by the USB subsystem for each new device
   * in the system. We need to check if the device is ours, and in
   * this case start handling it.
   * Note : it might be worth protecting this function by a global
   * spinlock... Or not, because maybe USB already deal with that...
   */
  static int stir_probe(struct usb_interface *intf,
  		      const struct usb_device_id *id)
  {
  	struct usb_device *dev = interface_to_usbdev(intf);
  	struct stir_cb *stir = NULL;
  	struct net_device *net;
  	int ret = -ENOMEM;
  
  	/* Allocate network device container. */
  	net = alloc_irdadev(sizeof(*stir));
  	if(!net)
  		goto err_out1;
  
  	SET_NETDEV_DEV(net, &intf->dev);
  	stir = netdev_priv(net);
  	stir->netdev = net;
  	stir->usbdev = dev;
  
  	ret = usb_reset_configuration(dev);
  	if (ret != 0) {
  		err("stir4200: usb reset configuration failed");
  		goto err_out2;
  	}
  
  	printk(KERN_INFO "SigmaTel STIr4200 IRDA/USB found at address %d, "
  		"Vendor: %x, Product: %x\n",
  	       dev->devnum, le16_to_cpu(dev->descriptor.idVendor),
  	       le16_to_cpu(dev->descriptor.idProduct));
  
  	/* Initialize QoS for this device */
  	irda_init_max_qos_capabilies(&stir->qos);
  
  	/* That's the Rx capability. */
  	stir->qos.baud_rate.bits       &= IR_2400 | IR_9600 | IR_19200 |
  					 IR_38400 | IR_57600 | IR_115200 |
  					 (IR_4000000 << 8);
  	stir->qos.min_turn_time.bits   &= qos_mtt_bits;
  	irda_qos_bits_to_value(&stir->qos);
  
  	/* Override the network functions we need to use */
  	net->netdev_ops = &stir_netdev_ops;
  
  	ret = register_netdev(net);
  	if (ret != 0)
  		goto err_out2;
  
  	dev_info(&intf->dev, "IrDA: Registered SigmaTel device %s\n",
  		 net->name);
  
  	usb_set_intfdata(intf, stir);
  
  	return 0;
  
  err_out2:
  	free_netdev(net);
  err_out1:
  	return ret;
  }
  
  /*
   * The current device is removed, the USB layer tell us to shut it down...
   */
  static void stir_disconnect(struct usb_interface *intf)
  {
  	struct stir_cb *stir = usb_get_intfdata(intf);
  
  	if (!stir)
  		return;
  
  	unregister_netdev(stir->netdev);
  	free_netdev(stir->netdev);
  
  	usb_set_intfdata(intf, NULL);
  }
  
  #ifdef CONFIG_PM
  /* USB suspend, so power off the transmitter/receiver */
  static int stir_suspend(struct usb_interface *intf, pm_message_t message)
  {
  	struct stir_cb *stir = usb_get_intfdata(intf);
  
  	netif_device_detach(stir->netdev);
  	return 0;
  }
  
  /* Coming out of suspend, so reset hardware */
  static int stir_resume(struct usb_interface *intf)
  {
  	struct stir_cb *stir = usb_get_intfdata(intf);
  
  	netif_device_attach(stir->netdev);
  
  	/* receiver restarted when send thread wakes up */
  	return 0;
  }
  #endif
  
  /*
   * USB device callbacks
   */
  static struct usb_driver irda_driver = {
  	.name		= "stir4200",
  	.probe		= stir_probe,
  	.disconnect	= stir_disconnect,
  	.id_table	= dongles,
  #ifdef CONFIG_PM
  	.suspend	= stir_suspend,
  	.resume		= stir_resume,
  #endif
  };
  
  module_usb_driver(irda_driver);
  