diff --git a/include/linux/hdlcdrv.h b/include/linux/hdlcdrv.h
new file mode 100644
index 0000000..4f6ee3b
--- /dev/null
+++ b/include/linux/hdlcdrv.h
@@ -0,0 +1,378 @@
+/*
+ * hdlcdrv.h  -- HDLC packet radio network driver.
+ * The Linux soundcard driver for 1200 baud and 9600 baud packet radio
+ * (C) 1996-1998 by Thomas Sailer, HB9JNX/AE4WA
+ */
+
+#ifndef _HDLCDRV_H
+#define _HDLCDRV_H
+
+/* -------------------------------------------------------------------- */
+/*
+ * structs for the IOCTL commands
+ */
+
+struct hdlcdrv_params {
+	int iobase;
+	int irq;
+	int dma;
+	int dma2;
+	int seriobase;
+	int pariobase;
+	int midiiobase;
+};	
+
+struct hdlcdrv_channel_params {
+	int tx_delay;  /* the transmitter keyup delay in 10ms units */
+	int tx_tail;   /* the transmitter keyoff delay in 10ms units */
+	int slottime;  /* the slottime in 10ms; usually 10 = 100ms */
+	int ppersist;  /* the p-persistence 0..255 */
+	int fulldup;   /* some driver do not support full duplex, setting */
+	               /* this just makes them send even if DCD is on */
+};	
+
+struct hdlcdrv_old_channel_state {
+  	int ptt;
+  	int dcd;
+  	int ptt_keyed;
+};
+
+struct hdlcdrv_channel_state {
+ 	int ptt;
+ 	int dcd;
+ 	int ptt_keyed;
+ 	unsigned long tx_packets;
+ 	unsigned long tx_errors;
+ 	unsigned long rx_packets;
+ 	unsigned long rx_errors;
+};
+
+struct hdlcdrv_ioctl {
+	int cmd;
+	union {
+		struct hdlcdrv_params mp;
+		struct hdlcdrv_channel_params cp;
+		struct hdlcdrv_channel_state cs;
+		struct hdlcdrv_old_channel_state ocs;
+		unsigned int calibrate;
+		unsigned char bits;
+		char modename[128];
+		char drivername[32];
+	} data;
+};
+
+/* -------------------------------------------------------------------- */
+
+/*
+ * ioctl values
+ */
+#define HDLCDRVCTL_GETMODEMPAR       0
+#define HDLCDRVCTL_SETMODEMPAR       1
+#define HDLCDRVCTL_MODEMPARMASK      2  /* not handled by hdlcdrv */
+#define HDLCDRVCTL_GETCHANNELPAR    10
+#define HDLCDRVCTL_SETCHANNELPAR    11
+#define HDLCDRVCTL_OLDGETSTAT       20
+#define HDLCDRVCTL_CALIBRATE        21
+#define HDLCDRVCTL_GETSTAT          22
+
+/*
+ * these are mainly for debugging purposes
+ */
+#define HDLCDRVCTL_GETSAMPLES       30
+#define HDLCDRVCTL_GETBITS          31
+
+/*
+ * not handled by hdlcdrv, but by its depending drivers
+ */
+#define HDLCDRVCTL_GETMODE          40
+#define HDLCDRVCTL_SETMODE          41
+#define HDLCDRVCTL_MODELIST         42
+#define HDLCDRVCTL_DRIVERNAME       43
+
+/*
+ * mask of needed modem parameters, returned by HDLCDRVCTL_MODEMPARMASK
+ */
+#define HDLCDRV_PARMASK_IOBASE      (1<<0)
+#define HDLCDRV_PARMASK_IRQ         (1<<1)
+#define HDLCDRV_PARMASK_DMA         (1<<2)
+#define HDLCDRV_PARMASK_DMA2        (1<<3)
+#define HDLCDRV_PARMASK_SERIOBASE   (1<<4)
+#define HDLCDRV_PARMASK_PARIOBASE   (1<<5)
+#define HDLCDRV_PARMASK_MIDIIOBASE  (1<<6)
+
+/* -------------------------------------------------------------------- */
+
+#ifdef __KERNEL__
+
+#include <linux/netdevice.h>
+#include <linux/if.h>
+#include <linux/spinlock.h>
+
+#define HDLCDRV_MAGIC      0x5ac6e778
+#define HDLCDRV_HDLCBUFFER  32 /* should be a power of 2 for speed reasons */
+#define HDLCDRV_BITBUFFER  256 /* should be a power of 2 for speed reasons */
+#undef HDLCDRV_LOOPBACK  /* define for HDLC debugging purposes */
+#define HDLCDRV_DEBUG
+
+/* maximum packet length, excluding CRC */
+#define HDLCDRV_MAXFLEN             400	
+
+
+struct hdlcdrv_hdlcbuffer {
+	spinlock_t lock;
+	unsigned rd, wr;
+	unsigned short buf[HDLCDRV_HDLCBUFFER];
+};
+
+#ifdef HDLCDRV_DEBUG
+struct hdlcdrv_bitbuffer {
+	unsigned int rd;
+	unsigned int wr;
+	unsigned int shreg;
+	unsigned char buffer[HDLCDRV_BITBUFFER];
+};
+
+static inline void hdlcdrv_add_bitbuffer(struct hdlcdrv_bitbuffer *buf, 
+					 unsigned int bit)
+{
+	unsigned char new;
+
+	new = buf->shreg & 1;
+	buf->shreg >>= 1;
+	buf->shreg |= (!!bit) << 7;
+	if (new) {
+		buf->buffer[buf->wr] = buf->shreg;
+		buf->wr = (buf->wr+1) % sizeof(buf->buffer);
+		buf->shreg = 0x80;
+	}
+}
+
+static inline void hdlcdrv_add_bitbuffer_word(struct hdlcdrv_bitbuffer *buf, 
+					      unsigned int bits)
+{
+	buf->buffer[buf->wr] = bits & 0xff;
+	buf->wr = (buf->wr+1) % sizeof(buf->buffer);
+	buf->buffer[buf->wr] = (bits >> 8) & 0xff;
+	buf->wr = (buf->wr+1) % sizeof(buf->buffer);
+
+}
+#endif /* HDLCDRV_DEBUG */
+
+/* -------------------------------------------------------------------- */
+/*
+ * Information that need to be kept for each driver. 
+ */
+
+struct hdlcdrv_ops {
+	/*
+	 * first some informations needed by the hdlcdrv routines
+	 */
+	const char *drvname;
+	const char *drvinfo;
+	/*
+	 * the routines called by the hdlcdrv routines
+	 */
+	int (*open)(struct net_device *);
+	int (*close)(struct net_device *);
+	int (*ioctl)(struct net_device *, struct ifreq *, 
+		     struct hdlcdrv_ioctl *, int);
+};
+
+struct hdlcdrv_state {
+	int magic;
+	int opened;
+
+	const struct hdlcdrv_ops *ops;
+
+	struct {
+		int bitrate;
+	} par;
+
+	struct hdlcdrv_pttoutput {
+		int dma2;
+		int seriobase;
+		int pariobase;
+		int midiiobase;
+		unsigned int flags;
+	} ptt_out;
+
+	struct hdlcdrv_channel_params ch_params;
+
+	struct hdlcdrv_hdlcrx {
+		struct hdlcdrv_hdlcbuffer hbuf;
+		long in_hdlc_rx;
+		/* 0 = sync hunt, != 0 receiving */
+		int rx_state;	
+		unsigned int bitstream;
+		unsigned int bitbuf;
+		int numbits;
+		unsigned char dcd;
+		
+		int len;
+		unsigned char *bp;
+		unsigned char buffer[HDLCDRV_MAXFLEN+2];
+	} hdlcrx;
+
+	struct hdlcdrv_hdlctx {
+		struct hdlcdrv_hdlcbuffer hbuf;
+		long in_hdlc_tx;
+		/*
+		 * 0 = send flags
+		 * 1 = send txtail (flags)
+		 * 2 = send packet
+		 */
+		int tx_state;	
+		int numflags;
+		unsigned int bitstream;
+		unsigned char ptt;
+		int calibrate;
+		int slotcnt;
+
+		unsigned int bitbuf;
+		int numbits;
+		
+		int len;
+		unsigned char *bp;
+		unsigned char buffer[HDLCDRV_MAXFLEN+2];
+	} hdlctx;
+
+#ifdef HDLCDRV_DEBUG
+	struct hdlcdrv_bitbuffer bitbuf_channel;
+	struct hdlcdrv_bitbuffer bitbuf_hdlc;
+#endif /* HDLCDRV_DEBUG */
+
+	struct net_device_stats stats;
+	int ptt_keyed;
+
+	/* queued skb for transmission */
+	struct sk_buff *skb;
+};
+
+
+/* -------------------------------------------------------------------- */
+
+static inline int hdlcdrv_hbuf_full(struct hdlcdrv_hdlcbuffer *hb) 
+{
+	unsigned long flags;
+	int ret;
+	
+	spin_lock_irqsave(&hb->lock, flags);
+	ret = !((HDLCDRV_HDLCBUFFER - 1 + hb->rd - hb->wr) % HDLCDRV_HDLCBUFFER);
+	spin_unlock_irqrestore(&hb->lock, flags);
+	return ret;
+}
+
+/* -------------------------------------------------------------------- */
+
+static inline int hdlcdrv_hbuf_empty(struct hdlcdrv_hdlcbuffer *hb)
+{
+	unsigned long flags;
+	int ret;
+	
+	spin_lock_irqsave(&hb->lock, flags);
+	ret = (hb->rd == hb->wr);
+	spin_unlock_irqrestore(&hb->lock, flags);
+	return ret;
+}
+
+/* -------------------------------------------------------------------- */
+
+static inline unsigned short hdlcdrv_hbuf_get(struct hdlcdrv_hdlcbuffer *hb)
+{
+	unsigned long flags;
+	unsigned short val;
+	unsigned newr;
+
+	spin_lock_irqsave(&hb->lock, flags);
+	if (hb->rd == hb->wr)
+		val = 0;
+	else {
+		newr = (hb->rd+1) % HDLCDRV_HDLCBUFFER;
+		val = hb->buf[hb->rd];
+		hb->rd = newr;
+	}
+	spin_unlock_irqrestore(&hb->lock, flags);
+	return val;
+}
+
+/* -------------------------------------------------------------------- */
+
+static inline void hdlcdrv_hbuf_put(struct hdlcdrv_hdlcbuffer *hb, 
+				    unsigned short val)
+{
+	unsigned newp;
+	unsigned long flags;
+	
+	spin_lock_irqsave(&hb->lock, flags);
+	newp = (hb->wr+1) % HDLCDRV_HDLCBUFFER;
+	if (newp != hb->rd) { 
+		hb->buf[hb->wr] = val & 0xffff;
+		hb->wr = newp;
+	}
+	spin_unlock_irqrestore(&hb->lock, flags);
+}
+
+/* -------------------------------------------------------------------- */
+
+static inline void hdlcdrv_putbits(struct hdlcdrv_state *s, unsigned int bits)
+{
+	hdlcdrv_hbuf_put(&s->hdlcrx.hbuf, bits);
+}
+
+static inline unsigned int hdlcdrv_getbits(struct hdlcdrv_state *s)
+{
+	unsigned int ret;
+
+	if (hdlcdrv_hbuf_empty(&s->hdlctx.hbuf)) {
+		if (s->hdlctx.calibrate > 0)
+			s->hdlctx.calibrate--;
+		else
+			s->hdlctx.ptt = 0;
+		ret = 0;
+	} else 
+		ret = hdlcdrv_hbuf_get(&s->hdlctx.hbuf);
+#ifdef HDLCDRV_LOOPBACK
+	hdlcdrv_hbuf_put(&s->hdlcrx.hbuf, ret);
+#endif /* HDLCDRV_LOOPBACK */
+	return ret;
+}
+
+static inline void hdlcdrv_channelbit(struct hdlcdrv_state *s, unsigned int bit)
+{
+#ifdef HDLCDRV_DEBUG
+	hdlcdrv_add_bitbuffer(&s->bitbuf_channel, bit);
+#endif /* HDLCDRV_DEBUG */
+}
+
+static inline void hdlcdrv_setdcd(struct hdlcdrv_state *s, int dcd)
+{
+	s->hdlcrx.dcd = !!dcd;
+}
+
+static inline int hdlcdrv_ptt(struct hdlcdrv_state *s)
+{
+	return s->hdlctx.ptt || (s->hdlctx.calibrate > 0);
+}
+
+/* -------------------------------------------------------------------- */
+
+void hdlcdrv_receiver(struct net_device *, struct hdlcdrv_state *);
+void hdlcdrv_transmitter(struct net_device *, struct hdlcdrv_state *);
+void hdlcdrv_arbitrate(struct net_device *, struct hdlcdrv_state *);
+struct net_device *hdlcdrv_register(const struct hdlcdrv_ops *ops,
+				    unsigned int privsize, const char *ifname,
+				    unsigned int baseaddr, unsigned int irq, 
+				    unsigned int dma);
+void hdlcdrv_unregister(struct net_device *dev);
+
+/* -------------------------------------------------------------------- */
+
+
+
+#endif /* __KERNEL__ */
+
+/* -------------------------------------------------------------------- */
+
+#endif /* _HDLCDRV_H */
+
+/* -------------------------------------------------------------------- */