Re: [PATCH] USB and Driver Core patches for 2.6.10

[Greg KH <greg@kroah.com>]

ChangeSet 1.1938.446.36, 2004/12/17 15:40:33-08:00, hkneissel@t-online.de

[PATCH] Re: garmin gps driver patch 0.23

From: Hermann Kneissel <hkneissel@t-online.de>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>


 drivers/usb/serial/Kconfig      |   13 
 drivers/usb/serial/Makefile     |    1 
 drivers/usb/serial/garmin_gps.c | 1542 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1556 insertions(+)


diff -Nru a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
--- a/drivers/usb/serial/Kconfig	2005-01-07 15:44:51 -08:00
+++ b/drivers/usb/serial/Kconfig	2005-01-07 15:44:51 -08:00
@@ -202,6 +202,19 @@
 	  To compile this driver as a module, choose M here: the
 	  module will be called io_ti.
 
+config USB_SERIAL_GARMIN
+       tristate "Garmin GPS driver"
+       depends on USB_SERIAL
+       help
+         Say Y here if you want to connect to your Garmin GPS.
+         Should work with most Garmin GPS devices which have a native USB port.
+
+         See <http://sourceforge.net/projects/garmin-gps> for the latest
+         version of the driver.
+
+         To compile this driver as a module, choose M here: the
+         module will be called garmin_gps.
+
 config USB_SERIAL_IPW
         tristate "USB IPWireless (3G UMTS TDD) Driver (EXPERIMENTAL)"
 	depends on USB_SERIAL && EXPERIMENTAL
diff -Nru a/drivers/usb/serial/Makefile b/drivers/usb/serial/Makefile
--- a/drivers/usb/serial/Makefile	2005-01-07 15:44:51 -08:00
+++ b/drivers/usb/serial/Makefile	2005-01-07 15:44:51 -08:00
@@ -19,6 +19,7 @@
 obj-$(CONFIG_USB_SERIAL_EDGEPORT_TI)		+= io_ti.o
 obj-$(CONFIG_USB_SERIAL_EMPEG)			+= empeg.o
 obj-$(CONFIG_USB_SERIAL_FTDI_SIO)		+= ftdi_sio.o
+obj-$(CONFIG_USB_SERIAL_GARMIN)			+= garmin_gps.o
 obj-$(CONFIG_USB_SERIAL_IPAQ)			+= ipaq.o
 obj-$(CONFIG_USB_SERIAL_IPW)			+= ipw.o
 obj-$(CONFIG_USB_SERIAL_IR)			+= ir-usb.o
diff -Nru a/drivers/usb/serial/garmin_gps.c b/drivers/usb/serial/garmin_gps.c
--- /dev/null	Wed Dec 31 16:00:00 196900
+++ b/drivers/usb/serial/garmin_gps.c	2005-01-07 15:44:51 -08:00
@@ -0,0 +1,1542 @@
+/*
+ * Garmin GPS driver
+ *
+ * Copyright (C) 2004 Hermann Kneissel hkneissel@t-online.de
+ *
+ * The latest version of the driver can be found at
+ * http://sourceforge.net/projects/garmin-gps/
+ *
+ * This driver has been derived from v2.1 of the visor driver.
+ *
+ * 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 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., 59 Temple Place - Suite 330, Boston, MA 02111 USA
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <asm/uaccess.h>
+#include <linux/usb.h>
+
+/* the mode to be set when the port ist opened */
+static int initial_mode = 1;
+
+/* debug flag */
+static int debug = 0;
+
+#include "usb-serial.h"
+
+#define GARMIN_VENDOR_ID             0x091E
+
+/*
+ * Version Information
+ */
+
+#define VERSION_MAJOR	0
+#define VERSION_MINOR	23
+
+#define _STR(s) #s
+#define _DRIVER_VERSION(a,b) "v" _STR(a) "." _STR(b)
+#define DRIVER_VERSION _DRIVER_VERSION(VERSION_MAJOR, VERSION_MINOR)
+#define DRIVER_AUTHOR "hermann kneissel"
+#define DRIVER_DESC "garmin gps driver"
+
+/* error codes returned by the driver */
+#define EINVPKT	1000	/* invalid packet structure */
+
+
+// size of the header of a packet using the usb protocol
+#define GARMIN_PKTHDR_LENGTH	12
+
+// max. possible size of a packet using the serial protocol 
+#define MAX_SERIAL_PKT_SIZ (3+255+3)
+
+// max. possible size of a packet with worst case stuffing
+#define MAX_SERIAL_PKT_SIZ_STUFFED MAX_SERIAL_PKT_SIZ+256
+
+// size of a buffer able to hold a complete (no stuffing) packet
+// (the document protocol does not contain packets with a larger
+//  size, but in theory a packet may be 64k+12 bytes - if in
+//  later protocol versions larger packet sizes occur, this value
+//  should be increased accordingly, so the input buffer is always 
+//  large enough the store a complete packet inclusive header)
+#define GPS_IN_BUFSIZ  (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ) 
+
+// size of a buffer able to hold a complete (incl. stuffing) packet
+#define GPS_OUT_BUFSIZ (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ_STUFFED) 
+
+// where to place the packet id of a serial packet, so we can
+// prepend the usb-packet header without the need to move the
+// packets data
+#define GSP_INITIAL_OFFSET (GARMIN_PKTHDR_LENGTH-2)
+
+// max. size of incoming private packets (header+1 param)
+#define PRIVPKTSIZ (GARMIN_PKTHDR_LENGTH+4)
+
+#define GARMIN_LAYERID_TRANSPORT  0
+#define GARMIN_LAYERID_APPL      20
+// our own layer-id to use for some control mechanisms
+#define GARMIN_LAYERID_PRIVATE	0x01106E4B
+
+#define GARMIN_PKTID_PVT_DATA	51
+#define GARMIN_PKTID_L001_COMMAND_DATA 10
+
+#define CMND_ABORT_TRANSFER 0
+
+// packet ids used in private layer
+#define PRIV_PKTID_SET_DEBUG	1
+#define PRIV_PKTID_SET_MODE	2
+#define PRIV_PKTID_INFO_REQ	3
+#define PRIV_PKTID_INFO_RESP	4
+#define PRIV_PKTID_RESET_REQ	5
+#define PRIV_PKTID_SET_DEF_MODE	6
+
+
+#define ETX	0x03
+#define DLE	0x10
+#define ACK	0x06
+#define NAK	0x15
+
+/* structure used to queue incoming packets */
+struct garmin_packet {
+	struct list_head  list;
+	int               seq;
+	int               size; // the real size of the data array, always > 0
+	__u8              data[1];
+};
+
+/* structure used to keep the current state of the driver */
+struct garmin_data {
+	__u8   state;
+	__u16  flags;
+	__u8   mode;
+	__u8   ignorePkts;
+	__u8   count;
+	__u8   pkt_id;
+	__u32  serial_num;
+	struct timer_list timer;
+	struct usb_serial_port *port;
+	int    seq_counter;
+	int    insize;
+	int    outsize;
+	__u8   inbuffer [GPS_IN_BUFSIZ];  /* tty -> usb */
+	__u8   outbuffer[GPS_OUT_BUFSIZ]; /* usb -> tty */
+	__u8   privpkt[4*6];
+	spinlock_t lock;
+	struct list_head pktlist;
+};
+
+
+#define STATE_NEW            0
+#define STATE_INITIAL_DELAY  1
+#define STATE_TIMEOUT        2
+#define STATE_SESSION_REQ1   3
+#define STATE_SESSION_REQ2   4
+#define STATE_ACTIVE         5
+
+#define STATE_RESET	     8
+#define STATE_DISCONNECTED   9
+#define STATE_WAIT_TTY_ACK  10
+#define STATE_GSP_WAIT_DATA 11
+
+#define MODE_NATIVE          0
+#define MODE_GARMIN_SERIAL   1
+
+// Flags used in garmin_data.flags:
+#define FLAGS_SESSION_REPLY_MASK  0x00C0
+#define FLAGS_SESSION_REPLY1_SEEN 0x0080
+#define FLAGS_SESSION_REPLY2_SEEN 0x0040
+#define FLAGS_BULK_IN_ACTIVE      0x0020
+#define FLAGS_THROTTLED           0x0010
+#define CLEAR_HALT_REQUIRED       0x0001
+
+#define FLAGS_QUEUING             0x0100
+#define FLAGS_APP_RESP_SEEN       0x0200
+#define FLAGS_APP_REQ_SEEN        0x0400
+#define FLAGS_DROP_DATA           0x0800
+
+#define FLAGS_GSP_SKIP            0x1000
+#define FLAGS_GSP_DLESEEN         0x2000
+
+
+
+
+
+
+/* function prototypes */
+static void gsp_next_packet(struct garmin_data * garmin_data_p);
+static int  garmin_write_bulk(struct usb_serial_port *port,
+			     const unsigned char *buf, int count);
+
+/* some special packets to be send or received */
+static unsigned char const GARMIN_START_SESSION_REQ[]
+	= { 0, 0, 0, 0,  5, 0, 0, 0, 0, 0, 0, 0 };
+static unsigned char const GARMIN_START_SESSION_REQ2[]
+	= { 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0 };
+static unsigned char const GARMIN_START_SESSION_REPLY[]
+	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
+static unsigned char const GARMIN_SESSION_ACTIVE_REPLY[]
+	= { 0, 0, 0, 0, 17, 0, 0, 0, 4, 0, 0, 0, 0, 16, 0, 0 };
+static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
+	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
+static unsigned char const GARMIN_APP_LAYER_REPLY[]
+	= { 0x14, 0, 0, 0 };
+static unsigned char const GARMIN_START_PVT_REQ[]
+	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
+static unsigned char const GARMIN_STOP_PVT_REQ[]
+	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
+static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
+	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
+static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
+	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
+static unsigned char const PRIVATE_REQ[]
+	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };
+
+
+
+static struct usb_device_id id_table [] = {
+	/* the same device id seems to be used by all usb enabled gps devices */
+	{ USB_DEVICE(GARMIN_VENDOR_ID, 3 ) },
+	{ }					/* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE (usb, id_table);
+
+static struct usb_driver garmin_driver = {
+	.owner =	THIS_MODULE,
+	.name =		"garmin_gps",
+	.probe =	usb_serial_probe,
+	.disconnect =	usb_serial_disconnect,
+	.id_table =	id_table,
+};
+
+
+static inline int noResponseFromAppLayer(struct garmin_data * garmin_data_p)
+{
+	return ((garmin_data_p->flags
+				& (FLAGS_APP_REQ_SEEN|FLAGS_APP_RESP_SEEN))
+	        == FLAGS_APP_REQ_SEEN);
+}
+
+
+static inline int getLayerId(const __u8 *usbPacket)
+{
+	return __le32_to_cpup((__le32 *)(usbPacket));
+}
+
+static inline int getPacketId(const __u8 *usbPacket)
+{
+	return __le32_to_cpup((__le32 *)(usbPacket+4));
+}
+
+static inline int getDataLength(const __u8 *usbPacket)
+{
+	return __le32_to_cpup((__le32 *)(usbPacket+8));
+}
+
+
+/*
+ * check if the usb-packet in buf contains an abort-transfer command.
+ * (if yes, all queued data will be dropped)
+ */
+static inline int isAbortTrfCmnd(const unsigned char *buf)
+{
+	if (0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ, 
+	                sizeof(GARMIN_STOP_TRANSFER_REQ)) ||
+	    0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2, 
+	                sizeof(GARMIN_STOP_TRANSFER_REQ_V2)))
+		return 1;
+	else
+		return 0;
+}
+
+
+
+static void send_to_tty(struct usb_serial_port *port,
+                        char *data, unsigned int actual_length)
+{
+	struct tty_struct *tty = port->tty;
+	int i;
+
+	if (tty && actual_length) {
+
+		usb_serial_debug_data(debug, &port->dev, 
+					__FUNCTION__, actual_length, data);
+
+		for (i = 0; i < actual_length ; ++i) {
+			/* if we insert more than TTY_FLIPBUF_SIZE characters,
+			   we drop them. */
+			if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
+				tty_flip_buffer_push(tty);
+			}
+			/* this doesn't actually push the data through unless
+			   tty->low_latency is set */
+			tty_insert_flip_char(tty, data[i], 0);
+		}
+		tty_flip_buffer_push(tty);
+	}
+}
+
+
+/******************************************************************************
+ * packet queue handling
+ ******************************************************************************/
+
+/*
+ * queue a received (usb-)packet for later processing
+ */
+static int pkt_add(struct garmin_data * garmin_data_p,
+                   unsigned char *data, unsigned int data_length)
+{
+	int result = 0;
+	unsigned long flags;
+	struct garmin_packet *pkt;
+
+	/* process only packets containg data ... */
+	if (data_length) {
+		garmin_data_p->flags |= FLAGS_QUEUING;
+		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
+		              GFP_ATOMIC);
+		if (pkt == 0) {
+			dev_err(&garmin_data_p->port->dev, "out of memory\n");
+			return 0;
+		}
+		pkt->size = data_length;
+		memcpy(pkt->data, data, data_length);
+
+		spin_lock_irqsave(&garmin_data_p->lock, flags);
+		result = list_empty(&garmin_data_p->pktlist);
+		pkt->seq = garmin_data_p->seq_counter++;
+		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
+		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+		/* in serial mode, if someone is waiting for data from
+		   the device, iconvert and send the next packet to tty. */
+		if (result && (garmin_data_p->state == STATE_GSP_WAIT_DATA)) {
+			gsp_next_packet(garmin_data_p);
+		}
+	}
+	return result;
+}
+
+
+/* get the next pending packet */
+static struct garmin_packet *pkt_pop(struct garmin_data * garmin_data_p)
+{
+	unsigned long flags;
+	struct garmin_packet *result = 0;
+
+	spin_lock_irqsave(&garmin_data_p->lock, flags);
+	if (!list_empty(&garmin_data_p->pktlist)) {
+		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
+		list_del(&result->list);
+	}
+	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+	return result;
+}
+
+
+/* free up all queued data */
+static void pkt_clear(struct garmin_data * garmin_data_p)
+{
+	unsigned long flags;
+	struct garmin_packet *result = 0;
+
+	dbg("%s", __FUNCTION__);
+
+	spin_lock_irqsave(&garmin_data_p->lock, flags);
+	while (!list_empty(&garmin_data_p->pktlist)) {
+		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
+		list_del(&result->list);
+		kfree(result);
+	}
+	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+}
+
+
+/******************************************************************************
+ * garmin serial protocol handling handling
+ ******************************************************************************/
+
+/* send an ack packet back to the tty */
+static int gsp_send_ack(struct garmin_data * garmin_data_p, __u8 pkt_id)
+{
+	__u8 pkt[10];
+        __u8 cksum = 0;
+        __u8 *ptr = pkt;
+        unsigned  l = 0;
+
+	dbg("%s - pkt-id: 0x%X.", __FUNCTION__, 0xFF & pkt_id);
+
+	*ptr++ = DLE;
+	*ptr++ = ACK;
+	cksum += ACK;
+
+	*ptr++ = 2;
+	cksum += 2;
+
+	*ptr++ = pkt_id;
+	cksum += pkt_id;
+
+	if (pkt_id == DLE) {
+		*ptr++ = DLE;
+	}
+
+	*ptr++ = 0;
+	*ptr++ = 0xFF & (-cksum);
+	*ptr++ = DLE;
+	*ptr++ = ETX;
+
+	l = ptr-pkt;
+
+	send_to_tty(garmin_data_p->port, pkt, l);
+	return 0;
+}
+
+
+
+/*
+ * called for a complete packet received from tty layer
+ *
+ * the complete packet (pkzid ... cksum) is in garmin_data_p->inbuf starting
+ * at GSP_INITIAL_OFFSET.
+ *
+ * count - number of bytes in the input buffer including space reserved for
+ *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet 
+ *         (including pkt-id, data-length a. cksum)
+ */
+static int gsp_rec_packet(struct garmin_data * garmin_data_p, int count)
+{
+	const __u8* recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
+        __le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;
+
+	int cksum = 0;
+	int n = 0;
+	int pktid = recpkt[0];
+	int size = recpkt[1];
+
+	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
+			       __FUNCTION__, count-GSP_INITIAL_OFFSET, recpkt);
+
+	if (size != (count-GSP_INITIAL_OFFSET-3)) {
+		dbg("%s - invalid size, expected %d bytes, got %d",
+			__FUNCTION__, size, (count-GSP_INITIAL_OFFSET-3));
+		return -EINVPKT;
+	}
+
+	cksum += *recpkt++;
+	cksum += *recpkt++;
+
+	// sanity check, remove after test ...
+	if ((__u8*)&(usbdata[3]) != recpkt) {
+		dbg("%s - ptr mismatch %p - %p",
+			__FUNCTION__, &(usbdata[4]), recpkt);
+		return -EINVPKT;
+	}
+
+	while (n < size) {
+		cksum += *recpkt++;
+		n++;
+	}
+
+       if ((0xff & (cksum + *recpkt)) != 0) {
+                dbg("%s - invalid checksum, expected %02x, got %02x",
+                        __FUNCTION__, 0xff & -cksum, 0xff & *recpkt);
+                return -EINVPKT;
+        }
+
+	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
+	usbdata[1] = __cpu_to_le32(pktid);
+	usbdata[2] = __cpu_to_le32(size);
+
+	garmin_write_bulk (garmin_data_p->port, garmin_data_p->inbuffer,
+			   GARMIN_PKTHDR_LENGTH+size);
+
+	/* if this was an abort-transfer command, flush all
+	   queued data. */
+	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
+		garmin_data_p->flags |= FLAGS_DROP_DATA;
+		pkt_clear(garmin_data_p);
+	}
+
+	return count;
+}
+
+
+
+/*
+ * Called for data received from tty
+ *
+ * buf contains the data read, it may span more than one packet or even
+ * incomplete packets
+ *
+ * input record should be a serial-record, but it may not be complete.
+ * Copy it into our local buffer, until an etx is seen (or an error
+ * occurs).
+ * Once the record is complete, convert into a usb packet and send it
+ * to the bulk pipe, send an ack back to the tty.
+ *
+ * If the input is an ack, just send the last queued packet to the
+ * tty layer.
+ *
+ * if the input is an abort command, drop all queued data.
+ */
+
+static int gsp_receive(struct garmin_data * garmin_data_p,
+                       const unsigned char *buf, int count)
+{
+	int offs = 0;
+	int ack_or_nak_seen = 0;
+	int i = 0;
+	__u8 *dest = garmin_data_p->inbuffer;
+	int size = garmin_data_p->insize;
+	// dleSeen: set if last byte read was a DLE
+	int dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
+	// skip: if set, skip incoming data until possible start of
+	//       new packet
+	int skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
+	__u8 data;
+
+	dbg("%s - dle=%d skip=%d size=%d count=%d",
+		__FUNCTION__, dleSeen, skip, size, count);
+
+	if (size == 0) {
+		size = GSP_INITIAL_OFFSET;
+	}
+
+	while (offs < count) {
+
+		data = *(buf+offs);
+		offs ++;
+
+		if (data == DLE) {
+			if (skip) { /* start of a new pkt */
+				skip = 0;
+				size = GSP_INITIAL_OFFSET;
+				dleSeen = 1;
+			} else if (dleSeen) {
+				dest[size++] = data;
+				dleSeen = 0;
+			} else {
+				dleSeen = 1;
+			}
+		} else if (data == ETX) {
+			if (dleSeen) {
+				/* packet complete */
+
+				data = dest[GSP_INITIAL_OFFSET];
+
+				if (data == ACK) {
+					ack_or_nak_seen = ACK;
+					dbg("ACK packet complete.");
+				} else if (data == NAK) {
+					ack_or_nak_seen = NAK;
+					dbg("NAK packet complete.");
+				} else {
+					dbg("packet complete "
+						        "- id=0x%X.",
+						        0xFF & data);
+					gsp_rec_packet(garmin_data_p, size);
+				}
+
+				skip = 1;
+				size = GSP_INITIAL_OFFSET;
+				dleSeen = 0;
+			} else {
+				dest[size++] = data;
+			}
+		} else if (!skip) {
+
+			if (dleSeen) {
+				dbg("non-masked DLE at %d - restarting", i);
+				size = GSP_INITIAL_OFFSET;
+				dleSeen = 0;
+			}
+
+			dest[size++] = data;
+		}
+
+		if (size >= GPS_IN_BUFSIZ) {
+			dbg("%s - packet too large.", __FUNCTION__);
+			skip = 1;
+			size = GSP_INITIAL_OFFSET;
+			dleSeen = 0;
+		}
+	}
+
+	garmin_data_p->insize = size;
+
+	// copy flags back to structure
+	if (skip)
+		garmin_data_p->flags |= FLAGS_GSP_SKIP;
+	else
+		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;
+
+	if (dleSeen)
+		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
+	else
+		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;
+
+	if (ack_or_nak_seen) {
+		garmin_data_p->state = STATE_GSP_WAIT_DATA;
+		gsp_next_packet(garmin_data_p);
+	}
+
+	return count;
+}
+
+
+
+
+/*
+ * Sends a usb packet to the tty
+ *
+ * Assumes, that all packages and at an usb-packet boundary.
+ *
+ * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
+ */
+int gsp_send(struct garmin_data * garmin_data_p, const unsigned char *buf,
+              int count)
+{
+	const unsigned char *src;
+	unsigned char *dst;
+	int pktid = 0;
+	int datalen = 0;
+	int cksum = 0;
+	int i=0;
+	int k;
+
+	dbg("%s - state %d - %d bytes.", __FUNCTION__,
+	         garmin_data_p->state, count);
+
+	k = garmin_data_p->outsize;
+	if ((k+count) > GPS_OUT_BUFSIZ) {
+		dbg("packet too large");
+		garmin_data_p->outsize = 0;
+		return -4;
+	}
+
+	memcpy(garmin_data_p->outbuffer+k, buf, count);
+	k += count;
+	garmin_data_p->outsize = k;
+
+	if (k >= GARMIN_PKTHDR_LENGTH) {
+		pktid  = getPacketId(garmin_data_p->outbuffer);
+		datalen= getDataLength(garmin_data_p->outbuffer);
+		i = GARMIN_PKTHDR_LENGTH + datalen;
+		if (k < i)
+			return 0;
+	} else {
+		return 0;
+	}
+
+	dbg("%s - %d bytes in buffer, %d bytes in pkt.", __FUNCTION__,
+	         k, i);
+
+	/* garmin_data_p->outbuffer now contains a complete packet */
+
+	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
+		                   __FUNCTION__, k, garmin_data_p->outbuffer);
+
+	garmin_data_p->outsize = 0;
+
+	if (GARMIN_LAYERID_APPL != getLayerId(garmin_data_p->outbuffer)) {
+		dbg("not an application packet (%d)", 
+		        getLayerId(garmin_data_p->outbuffer));
+		return -1;
+	}
+
+	if (pktid > 255) {
+		dbg("packet-id %d too large", pktid);
+		return -2;
+	}
+
+	if (datalen > 255) {
+		dbg("packet-size %d too large", datalen);
+		return -3;
+	}
+
+	/* the serial protocol should be able to handle this packet */
+
+	k = 0;
+	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
+	for (i=0; i<datalen; i++) {
+		if (*src++ == DLE)
+			k++;
+	}
+
+	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
+	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
+		/* can't add stuffing DLEs in place, move data to end 
+                   of buffer ... */
+		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
+		memcpy(dst, src, datalen);
+		src = dst;
+	}
+
+	dst = garmin_data_p->outbuffer;
+
+	*dst++ = DLE;
+	*dst++ = pktid;
+	cksum += pktid;
+	*dst++ = datalen;
+	cksum += datalen;
+	if (datalen == DLE)
+		*dst++ = DLE;
+
+	for (i=0; i<datalen; i++) {
+		__u8 c = *src++;
+		*dst++ = c;
+		cksum += c;
+		if (c == DLE)
+			*dst++ = DLE;
+	}
+		
+	cksum = 0xFF & -cksum;
+	*dst++ = cksum;
+	if (cksum == DLE)
+		*dst++ = DLE;
+	*dst++ = DLE;
+	*dst++ = ETX;
+
+	i = dst-garmin_data_p->outbuffer;
+
+	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);
+
+	garmin_data_p->pkt_id = pktid;
+	garmin_data_p->state  = STATE_WAIT_TTY_ACK;
+
+	return i;
+}
+
+
+
+
+
+/*
+ * Process the next pending data packet - if there is one
+ */
+static void gsp_next_packet(struct garmin_data * garmin_data_p)
+{
+	struct garmin_packet *pkt = 0;
+
+	while ((pkt = pkt_pop(garmin_data_p)) != 0)
+	{
+		dbg("%s - next pkt: %d", __FUNCTION__, pkt->seq);
+		if (gsp_send(garmin_data_p, pkt->data, pkt->size) > 0) {
+			kfree(pkt);
+			return;
+		}
+		kfree(pkt);
+	}
+}
+
+
+
+
+/******************************************************************************
+ * garmin native mode
+ ******************************************************************************/
+
+
+/*
+ * Called for data received from tty
+ *
+ * The input data is expected to be in garmin usb-packet format.
+ *
+ * buf contains the data read, it may span more than one packet
+ * or even incomplete packets
+ */
+static int nat_receive(struct garmin_data * garmin_data_p,
+                       const unsigned char *buf, int count)
+{
+	__u8 * dest;
+	int offs = 0;
+	int result = count;
+	int len;
+
+	while (offs < count) {
+		// if buffer contains header, copy rest of data
+		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
+			len = GARMIN_PKTHDR_LENGTH
+			      +getDataLength(garmin_data_p->inbuffer);
+		else
+			len = GARMIN_PKTHDR_LENGTH;
+
+		if (len >= GPS_IN_BUFSIZ) {
+			/* seem to be an invalid packet, ignore rest of input */
+			dbg("%s - packet size too large: %d",
+			        __FUNCTION__, len);
+			garmin_data_p->insize = 0;
+			count = 0;
+			result = -EINVPKT;
+		} else {
+			len -= garmin_data_p->insize;
+			if (len > (count-offs))
+				len = (count-offs);
+			if (len > 0) {
+				dest = garmin_data_p->inbuffer
+				       	+garmin_data_p->insize;
+				memcpy(dest, buf+offs, len);
+				garmin_data_p->insize += len;
+				offs += len;
+			}
+		}
+
+		/* do we have a complete packet ? */
+		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
+			len = GARMIN_PKTHDR_LENGTH+
+			   getDataLength(garmin_data_p->inbuffer);
+			if (garmin_data_p->insize >= len) {
+				garmin_write_bulk (garmin_data_p->port,
+				                   garmin_data_p->inbuffer,
+				                   len);
+				garmin_data_p->insize = 0;
+
+				/* if this was an abort-transfer command,
+				   flush all queued data. */
+				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
+					garmin_data_p->flags |= FLAGS_DROP_DATA;
+					pkt_clear(garmin_data_p);
+				}
+			}
+		}
+	}
+	return result;
+}
+
+
+/******************************************************************************
+ * private packets
+ ******************************************************************************/
+
+static void priv_status_resp(struct usb_serial_port *port)
+{
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;
+
+	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
+	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
+	pkt[2] = __cpu_to_le32(12);
+	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
+	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
+	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);
+
+	send_to_tty(port, (__u8*)pkt, 6*4);
+}
+
+
+/******************************************************************************
+ * Garmin specific driver functions
+ ******************************************************************************/
+
+static int process_resetdev_request(struct usb_serial_port *port)
+{
+	int status;
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+
+	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
+	garmin_data_p->state = STATE_RESET;
+	garmin_data_p->serial_num = 0;
+
+	usb_kill_urb (port->interrupt_in_urb);
+	dbg("%s - usb_reset_device", __FUNCTION__ );
+	status = usb_reset_device(port->serial->dev);
+	if (status)
+		dbg("%s - usb_reset_device failed: %d",
+			__FUNCTION__, status);
+	return status;
+}
+
+
+
+/*
+ * clear all cached data
+ */
+static int garmin_clear(struct garmin_data * garmin_data_p)
+{
+	int status = 0;
+
+	struct usb_serial_port *port = garmin_data_p->port;
+
+	if (port != 0 && garmin_data_p->flags & FLAGS_APP_RESP_SEEN) {
+		/* send a terminate command */
+		status = garmin_write_bulk(port, GARMIN_STOP_TRANSFER_REQ,
+		                           sizeof(GARMIN_STOP_TRANSFER_REQ));
+	}
+
+	/* flush all queued data */
+	pkt_clear(garmin_data_p);
+
+	garmin_data_p->insize = 0;
+	garmin_data_p->outsize = 0;
+
+	return status;
+}
+
+
+
+
+
+
+static int garmin_init_session(struct usb_serial_port *port)
+{
+	struct usb_serial *serial = port->serial;
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+	int status = 0;
+
+	if (status == 0) {
+		usb_kill_urb (port->interrupt_in_urb);
+
+		dbg("%s - adding interrupt input", __FUNCTION__);
+		port->interrupt_in_urb->dev = serial->dev;
+		status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
+		if (status)
+			dev_err(&serial->dev->dev,
+			        "%s - failed submitting interrupt urb,"
+				" error %d\n",
+			        __FUNCTION__, status);
+	}
+
+	if (status == 0) {
+		dbg("%s - starting session ...", __FUNCTION__);
+		garmin_data_p->state = STATE_ACTIVE;
+		status = garmin_write_bulk(port, GARMIN_START_SESSION_REQ,
+		                           sizeof(GARMIN_START_SESSION_REQ));
+
+		if (status >= 0) {
+
+			garmin_data_p->ignorePkts++;
+
+			/* not needed, but the win32 driver does it too ... */
+			status = garmin_write_bulk(port,
+						   GARMIN_START_SESSION_REQ2,
+			                           sizeof(GARMIN_START_SESSION_REQ2));
+			if (status >= 0) {
+				status = 0;
+				garmin_data_p->ignorePkts++;
+			}
+		}
+	}
+
+	return status;
+}
+
+
+
+
+
+static int garmin_open (struct usb_serial_port *port, struct file *filp)
+{
+	int status = 0;
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	/*
+	 * Force low_latency on so that our tty_push actually forces the data
+	 * through, otherwise it is scheduled, and with high data rates (like
+	 * with OHCI) data can get lost.
+	 */
+	if (port->tty)
+		port->tty->low_latency = 1;
+
+	garmin_data_p->mode  = initial_mode;
+	garmin_data_p->count = 0;
+	garmin_data_p->flags = 0;
+
+	/* shutdown any bulk reads that might be going on */
+	usb_kill_urb (port->write_urb);
+	usb_kill_urb (port->read_urb);
+
+	if (garmin_data_p->state == STATE_RESET) {
+		status = garmin_init_session(port);
+	}
+
+	garmin_data_p->state = STATE_ACTIVE;
+
+	return status;
+}
+
+
+static void garmin_close (struct usb_serial_port *port, struct file * filp)
+{
+	struct usb_serial *serial = port->serial;
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+
+	dbg("%s - port %d - mode=%d state=%d flags=0x%X", __FUNCTION__,
+		port->number, garmin_data_p->mode,
+		garmin_data_p->state, garmin_data_p->flags);
+
+	if (!serial)
+		return;
+
+	garmin_clear(garmin_data_p);
+
+	/* shutdown our urbs */
+	usb_kill_urb (port->read_urb);
+	usb_kill_urb (port->write_urb);
+
+	if (noResponseFromAppLayer(garmin_data_p) ||
+	    ((garmin_data_p->flags & CLEAR_HALT_REQUIRED) != 0)) {
+		process_resetdev_request(port);
+		garmin_data_p->state = STATE_RESET;
+	} else {
+		garmin_data_p->state = STATE_DISCONNECTED;
+	}
+}
+
+
+static void garmin_write_bulk_callback (struct urb *urb, struct pt_regs *regs)
+{
+	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+
+	/* free up the transfer buffer, as usb_free_urb() does not do this */
+	kfree (urb->transfer_buffer);
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	if (urb->status) {
+		dbg("%s - nonzero write bulk status received: %d",
+			__FUNCTION__, urb->status);
+		garmin_data_p->flags |= CLEAR_HALT_REQUIRED;
+	}
+
+	schedule_work(&port->work);
+}
+
+
+static int garmin_write_bulk (struct usb_serial_port *port,
+                              const unsigned char *buf, int count)
+{
+	struct usb_serial *serial = port->serial;
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+	struct urb *urb;
+	unsigned char *buffer;
+	int status;
+
+	dbg("%s - port %d, state %d", __FUNCTION__, port->number,
+		garmin_data_p->state);
+
+	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
+
+	buffer = kmalloc (count, GFP_ATOMIC);
+	if (!buffer) {
+		dev_err(&port->dev, "out of memory\n");
+		return -ENOMEM;
+	}
+
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if (!urb) {
+		dev_err(&port->dev, "no more free urbs\n");
+		kfree (buffer);
+		return -ENOMEM;
+	}
+
+	memcpy (buffer, buf, count);
+
+	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, buffer);
+
+	usb_fill_bulk_urb (urb, serial->dev,
+			 	usb_sndbulkpipe (serial->dev,
+				port->bulk_out_endpointAddress),
+				buffer, count,
+				garmin_write_bulk_callback, port);
+	urb->transfer_flags |= URB_ZERO_PACKET;
+
+	if (GARMIN_LAYERID_APPL == getLayerId(buffer)) {
+		garmin_data_p->flags |= FLAGS_APP_REQ_SEEN;
+		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
+			pkt_clear(garmin_data_p);
+			garmin_data_p->state = STATE_GSP_WAIT_DATA;
+		}
+	}
+
+	/* send it down the pipe */
+	status = usb_submit_urb(urb, GFP_ATOMIC);
+	if (status) {
+		dev_err(&port->dev,
+		        "%s - usb_submit_urb(write bulk) "
+		        "failed with status = %d\n",
+				__FUNCTION__, status);
+		count = status;
+	} else {
+
+		if (GARMIN_LAYERID_APPL == getLayerId(buffer)
+		    && (garmin_data_p->mode == MODE_GARMIN_SERIAL))  {
+
+			gsp_send_ack(garmin_data_p, buffer[4]);
+		}
+	}
+
+	/* we are done with this urb, so let the host driver
+	 * really free it when it is finished with it */
+	usb_free_urb (urb);
+
+	return count;
+}
+
+
+
+static int garmin_write (struct usb_serial_port *port,
+                         const unsigned char *buf, int count)
+{
+	int pktid, pktsiz, len;
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;
+
+	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, buf);
+
+	/* check for our private packets */
+	if (count >= GARMIN_PKTHDR_LENGTH) {
+
+		len = PRIVPKTSIZ;
+		if (count < len)
+			len = count;
+
+		memcpy(garmin_data_p->privpkt, buf, len);
+
+		pktsiz = getDataLength(garmin_data_p->privpkt);
+		pktid  = getPacketId(garmin_data_p->privpkt);
+
+		if (count == (GARMIN_PKTHDR_LENGTH+pktsiz)
+		    && GARMIN_LAYERID_PRIVATE == getLayerId(garmin_data_p->privpkt)) {
+
+			dbg("%s - processing private request %d",
+				__FUNCTION__, pktid);
+
+			// drop all unfinished transfers
+			garmin_clear(garmin_data_p);
+
+			switch(pktid) {
+
+			case PRIV_PKTID_SET_DEBUG:
+				if (pktsiz != 4)
+					return -EINVPKT;
+				debug = __le32_to_cpu(privpkt[3]);
+				dbg("%s - debug level set to 0x%X",
+					__FUNCTION__, debug);
+				break;
+
+			case PRIV_PKTID_SET_MODE:
+				if (pktsiz != 4)
+					return -EINVPKT;
+				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
+				dbg("%s - mode set to %d",
+					__FUNCTION__, garmin_data_p->mode);
+				break;
+
+			case PRIV_PKTID_INFO_REQ:
+				priv_status_resp(port);
+				break;
+
+			case PRIV_PKTID_RESET_REQ:
+				garmin_data_p->flags |= FLAGS_APP_REQ_SEEN;
+				break;
+
+			case PRIV_PKTID_SET_DEF_MODE:
+				if (pktsiz != 4)
+					return -EINVPKT;
+				initial_mode = __le32_to_cpu(privpkt[3]);
+				dbg("%s - initial_mode set to %d",
+					__FUNCTION__,
+					garmin_data_p->mode);
+				break;
+			}
+			return count;
+		}
+	}
+
+	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
+		return gsp_receive(garmin_data_p, buf, count);
+	} else {	/* MODE_NATIVE */
+		return nat_receive(garmin_data_p, buf, count);
+	}
+}
+
+
+static int garmin_write_room (struct usb_serial_port *port)
+{
+	/*
+	 * Report back the bytes currently available in the output buffer.
+	 */
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
+}
+
+
+static int garmin_chars_in_buffer (struct usb_serial_port *port)
+{
+	/*
+	 * Report back the number of bytes currently in our input buffer.
+         * Will this lock up the driver - the buffer contains an incomplete
+         * package which will not be written to the device until it
+         * has been completed ?
+         */
+	//struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+	//return garmin_data_p->insize;
+	return 0;
+}
+
+
+static void garmin_read_process(struct garmin_data * garmin_data_p,
+				 unsigned char *data, unsigned data_length)
+{
+	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
+		/* abort-transfer cmd is actice */
+		dbg("%s - pkt dropped", __FUNCTION__);
+	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
+	           garmin_data_p->state != STATE_RESET ) {
+
+		/* remember any appl.layer packets, so we know
+		   if a reset is required or not when closing
+		   the device */
+		if (0 == memcmp(data, GARMIN_APP_LAYER_REPLY,
+		                sizeof(GARMIN_APP_LAYER_REPLY)))
+			garmin_data_p->flags |= FLAGS_APP_RESP_SEEN;
+
+		/* if throttling is active or postprecessing is required
+		   put the received data in th input queue, otherwise
+		   send it directly to the tty port */
+		if (garmin_data_p->flags & FLAGS_QUEUING) {
+			pkt_add(garmin_data_p, data, data_length);
+		} else if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
+			if (getLayerId(data) == GARMIN_LAYERID_APPL) {
+				pkt_add(garmin_data_p, data, data_length);
+			}
+		} else {
+			send_to_tty(garmin_data_p->port, data, data_length);
+		}
+	}
+}
+
+
+static void garmin_read_bulk_callback (struct urb *urb, struct pt_regs *regs)
+{
+	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
+	struct usb_serial *serial =  port->serial;
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+	unsigned char *data = urb->transfer_buffer;
+	int status;
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	if (!serial) {
+		dbg("%s - bad serial pointer, exiting", __FUNCTION__);
+		return;
+	}
+
+	if (urb->status) {
+		dbg("%s - nonzero read bulk status received: %d",
+			__FUNCTION__, urb->status);
+		return;
+	}
+
+	usb_serial_debug_data(debug, &port->dev, 
+				__FUNCTION__, urb->actual_length, data);
+
+	garmin_read_process(garmin_data_p, data, urb->actual_length);
+
+	/* Continue trying to read until nothing more is received  */
+	if (urb->actual_length > 0) {
+		usb_fill_bulk_urb (port->read_urb, serial->dev,
+			   usb_rcvbulkpipe (serial->dev,
+					    port->bulk_in_endpointAddress),
+			   port->read_urb->transfer_buffer,
+			   port->read_urb->transfer_buffer_length,
+			   garmin_read_bulk_callback, port);
+		status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
+		if (status)
+			dev_err(&port->dev,
+				"%s - failed resubmitting read urb, error %d\n",
+			        __FUNCTION__, status);
+	}
+	return;
+}
+
+
+static void garmin_read_int_callback (struct urb *urb, struct pt_regs *regs)
+{
+	int status;
+	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
+	struct usb_serial *serial = port->serial;
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+	unsigned char *data = urb->transfer_buffer;
+
+	switch (urb->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",
+			__FUNCTION__, urb->status);
+		return;
+	default:
+		dbg("%s - nonzero urb status received: %d",
+			__FUNCTION__, urb->status);
+		return;
+	}
+
+	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, 
+				urb->actual_length, urb->transfer_buffer);
+
+	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
+	    0 == memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
+		        sizeof(GARMIN_BULK_IN_AVAIL_REPLY))) {
+
+		dbg("%s - bulk data available.", __FUNCTION__);
+
+		/* bulk data available */
+		usb_fill_bulk_urb (port->read_urb, serial->dev,
+				usb_rcvbulkpipe (serial->dev,
+				port->bulk_in_endpointAddress),
+				port->read_urb->transfer_buffer,
+				port->read_urb->transfer_buffer_length,
+				garmin_read_bulk_callback, port);
+		status = usb_submit_urb(port->read_urb, GFP_KERNEL);
+		if (status) {
+			dev_err(&port->dev,
+				"%s - failed submitting read urb, error %d\n",
+			__FUNCTION__, status);
+		}
+
+	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
+			 && 0 == memcmp(data, GARMIN_START_SESSION_REPLY,
+			                sizeof(GARMIN_START_SESSION_REPLY))) {
+
+		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
+
+		/* save the serial number */
+		garmin_data_p->serial_num 
+			= __le32_to_cpup((__le32*)(data+GARMIN_PKTHDR_LENGTH));
+
+		dbg("%s - start-of-session reply seen - serial %u.",
+			__FUNCTION__, garmin_data_p->serial_num);
+	}
+
+	if (garmin_data_p->ignorePkts) {
+		/* this reply belongs to a request generated by the driver,
+		   ignore it. */
+		dbg("%s - pkt ignored (%d)",
+			__FUNCTION__, garmin_data_p->ignorePkts);
+		garmin_data_p->ignorePkts--;
+	} else {
+		garmin_read_process(garmin_data_p, data, urb->actual_length);
+	}
+
+	port->interrupt_in_urb->dev = port->serial->dev;
+	status = usb_submit_urb (urb, GFP_ATOMIC);
+	if (status)
+		dev_err(&urb->dev->dev,
+			"%s - Error %d submitting interrupt urb\n",
+			__FUNCTION__, status);
+}
+
+
+/*
+ * Sends the next queued packt to the tty port (garmin native mode only)
+ * and then sets a timer to call itself again until all queued data
+ * is sent.
+ */
+static int garmin_flush_queue(struct garmin_data * garmin_data_p)
+{
+	struct garmin_packet *pkt;
+
+	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
+		pkt = pkt_pop(garmin_data_p);
+		if (pkt != 0) {
+
+			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
+			kfree(pkt);
+			mod_timer(&garmin_data_p->timer, (1)+jiffies);
+
+		} else {
+			garmin_data_p->flags &= ~FLAGS_QUEUING;
+		}
+	}
+	return 0;
+}
+
+
+static void garmin_throttle (struct usb_serial_port *port)
+{
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+	/* set flag, data received will be put into a queue
+	   for later processing */
+	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
+}
+
+
+static void garmin_unthrottle (struct usb_serial_port *port)
+{
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+	garmin_data_p->flags &= ~FLAGS_THROTTLED;
+
+	/* in native mode send queued data to tty, in
+	   serial mode nothing needs to be done here */
+	if (garmin_data_p->mode == MODE_NATIVE)
+		garmin_flush_queue(garmin_data_p);
+}
+
+
+
+/*
+ * The timer is currently only used to send queued packets to
+ * the tty in cases where the protocol provides no own handshaking
+ * to initiate the transfer.
+ */
+static void timeout_handler(unsigned long data)
+{
+	struct garmin_data *garmin_data_p = (struct garmin_data *) data;
+
+	/* send the next queued packet to the tty port */
+	if (garmin_data_p->mode == MODE_NATIVE)
+		if (garmin_data_p->flags & FLAGS_QUEUING)
+			garmin_flush_queue(garmin_data_p);
+}
+
+
+
+static int garmin_attach (struct usb_serial *serial)
+{
+	int status = 0;
+	struct usb_serial_port *port = serial->port[0];
+	struct garmin_data * garmin_data_p = 0;
+
+	dbg("%s", __FUNCTION__);
+
+	garmin_data_p = kmalloc (sizeof(struct garmin_data), GFP_KERNEL);
+	if (garmin_data_p == NULL) {
+		dev_err(&port->dev, "%s - Out of memory\n", __FUNCTION__);
+		return -ENOMEM;
+	}
+	memset (garmin_data_p, 0, sizeof(struct garmin_data));
+	init_timer(&garmin_data_p->timer);
+	spin_lock_init(&garmin_data_p->lock);
+	INIT_LIST_HEAD(&garmin_data_p->pktlist);
+	//garmin_data_p->timer.expires = jiffies + session_timeout;
+	garmin_data_p->timer.data = (unsigned long)garmin_data_p;
+	garmin_data_p->timer.function = timeout_handler;
+	garmin_data_p->port = port;
+	garmin_data_p->state = 0;
+	garmin_data_p->count = 0;
+	usb_set_serial_port_data(port, garmin_data_p);
+
+	status = garmin_init_session(port);
+
+	return status;
+}
+
+
+static void garmin_shutdown (struct usb_serial *serial)
+{
+	struct usb_serial_port *port = serial->port[0];
+	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
+
+	dbg("%s", __FUNCTION__);
+
+	usb_kill_urb (port->interrupt_in_urb);
+	del_timer_sync(&garmin_data_p->timer);
+	kfree (garmin_data_p);
+	usb_set_serial_port_data(port, NULL);
+}
+
+
+
+
+
+
+
+/* All of the device info needed */
+static struct usb_serial_device_type garmin_device = {
+	.owner               = THIS_MODULE,
+	.name                = "Garmin GPS usb/tty",
+	.short_name          = "garmin_gps",
+	.id_table            = id_table,
+	.num_interrupt_in    = 1,
+	.num_bulk_in         = 1,
+	.num_bulk_out        = 1,
+	.num_ports           = 1,
+	.open                = garmin_open,
+	.close               = garmin_close,
+	.throttle            = garmin_throttle,
+	.unthrottle          = garmin_unthrottle,
+	.attach              = garmin_attach,
+	.shutdown            = garmin_shutdown,
+	.write               = garmin_write,
+	.write_room          = garmin_write_room,
+	.chars_in_buffer     = garmin_chars_in_buffer,
+	.write_bulk_callback = garmin_write_bulk_callback,
+	.read_bulk_callback  = garmin_read_bulk_callback,
+	.read_int_callback   = garmin_read_int_callback,
+};
+
+
+static int __init garmin_init (void)
+{
+	int retval;
+
+	retval = usb_serial_register(&garmin_device);
+	if (retval)
+		goto failed_garmin_register;
+	retval = usb_register(&garmin_driver);
+	if (retval)
+		goto failed_usb_register;
+	info(DRIVER_DESC " " DRIVER_VERSION);
+
+	return 0;
+failed_usb_register:
+	usb_serial_deregister(&garmin_device);
+failed_garmin_register:
+	return retval;
+}
+
+
+static void __exit garmin_exit (void)
+{
+	usb_deregister (&garmin_driver);
+	usb_serial_deregister (&garmin_device);
+}
+
+
+
+
+module_init(garmin_init);
+module_exit(garmin_exit);
+
+MODULE_AUTHOR( DRIVER_AUTHOR );
+MODULE_DESCRIPTION( DRIVER_DESC );
+MODULE_LICENSE("GPL");
+
+module_param(debug, bool, S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(debug, "Debug enabled or not");
+module_param(initial_mode, int, S_IRUGO);
+MODULE_PARM_DESC(initial_mode, "Initial mode");
+