Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / usb / serial / garmin_gps.c
diff --git a/kernel/drivers/usb/serial/garmin_gps.c b/kernel/drivers/usb/serial/garmin_gps.c
new file mode 100644 (file)
index 0000000..db591d1
--- /dev/null
@@ -0,0 +1,1456 @@
+/*
+ * Garmin GPS driver
+ *
+ * Copyright (C) 2006-2011 Hermann Kneissel herkne@gmx.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/kernel.h>
+#include <linux/errno.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 <linux/uaccess.h>
+#include <linux/atomic.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+
+/* the mode to be set when the port ist opened */
+static int initial_mode = 1;
+
+#define GARMIN_VENDOR_ID             0x091E
+
+/*
+ * Version Information
+ */
+
+#define VERSION_MAJOR  0
+#define VERSION_MINOR  36
+
+#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;
+       /* the real size of the data array, always > 0 */
+       int               size;
+       __u8              data[1];
+};
+
+/* structure used to keep the current state of the driver */
+struct garmin_data {
+       __u8   state;
+       __u16  flags;
+       __u8   mode;
+       __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_BULK_IN_RESTART     0x0010
+#define FLAGS_THROTTLED           0x0008
+#define APP_REQ_SEEN              0x0004
+#define APP_RESP_SEEN             0x0002
+#define CLEAR_HALT_REQUIRED       0x0001
+
+#define FLAGS_QUEUING             0x0100
+#define FLAGS_DROP_DATA           0x0800
+
+#define FLAGS_GSP_SKIP            0x1000
+#define FLAGS_GSP_DLESEEN         0x2000
+
+
+
+
+
+
+/* function prototypes */
+static int 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,
+                            int dismiss_ack);
+
+/* 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_REPLY[]
+       = { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 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 const 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 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)
+{
+       if (actual_length) {
+               usb_serial_debug_data(&port->dev, __func__, actual_length, data);
+               tty_insert_flip_string(&port->port, data, actual_length);
+               tty_flip_buffer_push(&port->port);
+       }
+}
+
+
+/******************************************************************************
+ * 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 state = 0;
+       int result = 0;
+       unsigned long flags;
+       struct garmin_packet *pkt;
+
+       /* process only packets containing data ... */
+       if (data_length) {
+               pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
+                                                               GFP_ATOMIC);
+               if (!pkt)
+                       return 0;
+
+               pkt->size = data_length;
+               memcpy(pkt->data, data, data_length);
+
+               spin_lock_irqsave(&garmin_data_p->lock, flags);
+               garmin_data_p->flags |= FLAGS_QUEUING;
+               result = list_empty(&garmin_data_p->pktlist);
+               pkt->seq = garmin_data_p->seq_counter++;
+               list_add_tail(&pkt->list, &garmin_data_p->pktlist);
+               state = garmin_data_p->state;
+               spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+               dev_dbg(&garmin_data_p->port->dev,
+                       "%s - added: pkt: %d - %d bytes\n", __func__,
+                       pkt->seq, data_length);
+
+               /* in serial mode, if someone is waiting for data from
+                  the device, convert and send the next packet to tty. */
+               if (result && (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 = NULL;
+
+       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 = NULL;
+
+       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;
+
+       dev_dbg(&garmin_data_p->port->dev, "%s - pkt-id: 0x%X.\n", __func__,
+               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 (pktid ... 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)
+{
+       struct device *dev = &garmin_data_p->port->dev;
+       unsigned long flags;
+       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(&garmin_data_p->port->dev, __func__,
+                             count-GSP_INITIAL_OFFSET, recpkt);
+
+       if (size != (count-GSP_INITIAL_OFFSET-3)) {
+               dev_dbg(dev, "%s - invalid size, expected %d bytes, got %d\n",
+                       __func__, size, (count-GSP_INITIAL_OFFSET-3));
+               return -EINVPKT;
+       }
+
+       cksum += *recpkt++;
+       cksum += *recpkt++;
+
+       /* sanity check, remove after test ... */
+       if ((__u8 *)&(usbdata[3]) != recpkt) {
+               dev_dbg(dev, "%s - ptr mismatch %p - %p\n", __func__,
+                       &(usbdata[4]), recpkt);
+               return -EINVPKT;
+       }
+
+       while (n < size) {
+               cksum += *recpkt++;
+               n++;
+       }
+
+       if ((0xff & (cksum + *recpkt)) != 0) {
+               dev_dbg(dev, "%s - invalid checksum, expected %02x, got %02x\n",
+                       __func__, 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, 0);
+
+       /* if this was an abort-transfer command, flush all
+          queued data. */
+       if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
+               spin_lock_irqsave(&garmin_data_p->lock, flags);
+               garmin_data_p->flags |= FLAGS_DROP_DATA;
+               spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+               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)
+{
+       struct device *dev = &garmin_data_p->port->dev;
+       unsigned long flags;
+       int offs = 0;
+       int ack_or_nak_seen = 0;
+       __u8 *dest;
+       int size;
+       /* dleSeen: set if last byte read was a DLE */
+       int dleSeen;
+       /* skip: if set, skip incoming data until possible start of
+        *       new packet
+        */
+       int skip;
+       __u8 data;
+
+       spin_lock_irqsave(&garmin_data_p->lock, flags);
+       dest = garmin_data_p->inbuffer;
+       size = garmin_data_p->insize;
+       dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
+       skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
+       spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+       /* dev_dbg(dev, "%s - dle=%d skip=%d size=%d count=%d\n",
+               __func__, 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;
+                                       dev_dbg(dev, "ACK packet complete.\n");
+                               } else if (data == NAK) {
+                                       ack_or_nak_seen = NAK;
+                                       dev_dbg(dev, "NAK packet complete.\n");
+                               } else {
+                                       dev_dbg(dev, "packet complete - id=0x%X.\n",
+                                               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) {
+                               size = GSP_INITIAL_OFFSET;
+                               dleSeen = 0;
+                       }
+
+                       dest[size++] = data;
+               }
+
+               if (size >= GPS_IN_BUFSIZ) {
+                       dev_dbg(dev, "%s - packet too large.\n", __func__);
+                       skip = 1;
+                       size = GSP_INITIAL_OFFSET;
+                       dleSeen = 0;
+               }
+       }
+
+       spin_lock_irqsave(&garmin_data_p->lock, flags);
+
+       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;
+
+       spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+       if (ack_or_nak_seen) {
+               if (gsp_next_packet(garmin_data_p) > 0)
+                       garmin_data_p->state = STATE_ACTIVE;
+               else
+                       garmin_data_p->state = STATE_GSP_WAIT_DATA;
+       }
+       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
+ */
+static int gsp_send(struct garmin_data *garmin_data_p,
+                   const unsigned char *buf, int count)
+{
+       struct device *dev = &garmin_data_p->port->dev;
+       const unsigned char *src;
+       unsigned char *dst;
+       int pktid = 0;
+       int datalen = 0;
+       int cksum = 0;
+       int i = 0;
+       int k;
+
+       dev_dbg(dev, "%s - state %d - %d bytes.\n", __func__,
+               garmin_data_p->state, count);
+
+       k = garmin_data_p->outsize;
+       if ((k+count) > GPS_OUT_BUFSIZ) {
+               dev_dbg(dev, "packet too large\n");
+               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;
+       }
+
+       dev_dbg(dev, "%s - %d bytes in buffer, %d bytes in pkt.\n", __func__, k, i);
+
+       /* garmin_data_p->outbuffer now contains a complete packet */
+
+       usb_serial_debug_data(&garmin_data_p->port->dev, __func__, k,
+                             garmin_data_p->outbuffer);
+
+       garmin_data_p->outsize = 0;
+
+       if (GARMIN_LAYERID_APPL != getLayerId(garmin_data_p->outbuffer)) {
+               dev_dbg(dev, "not an application packet (%d)\n",
+                               getLayerId(garmin_data_p->outbuffer));
+               return -1;
+       }
+
+       if (pktid > 255) {
+               dev_dbg(dev, "packet-id %d too large\n", pktid);
+               return -2;
+       }
+
+       if (datalen > 255) {
+               dev_dbg(dev, "packet-size %d too large\n", 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 int gsp_next_packet(struct garmin_data *garmin_data_p)
+{
+       int result = 0;
+       struct garmin_packet *pkt = NULL;
+
+       while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
+               dev_dbg(&garmin_data_p->port->dev, "%s - next pkt: %d\n", __func__, pkt->seq);
+               result = gsp_send(garmin_data_p, pkt->data, pkt->size);
+               if (result > 0) {
+                       kfree(pkt);
+                       return result;
+               }
+               kfree(pkt);
+       }
+       return result;
+}
+
+
+
+/******************************************************************************
+ * 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)
+{
+       unsigned long flags;
+       __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) {
+                       /* seems to be an invalid packet, ignore rest
+                          of input */
+                       dev_dbg(&garmin_data_p->port->dev,
+                               "%s - packet size too large: %d\n",
+                               __func__, 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, 0);
+                               garmin_data_p->insize = 0;
+
+                               /* if this was an abort-transfer command,
+                                  flush all queued data. */
+                               if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
+                                       spin_lock_irqsave(&garmin_data_p->lock,
+                                                                       flags);
+                                       garmin_data_p->flags |= FLAGS_DROP_DATA;
+                                       spin_unlock_irqrestore(
+                                               &garmin_data_p->lock, flags);
+                                       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)
+{
+       unsigned long flags;
+       int status;
+       struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
+
+       spin_lock_irqsave(&garmin_data_p->lock, flags);
+       garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
+       garmin_data_p->state = STATE_RESET;
+       garmin_data_p->serial_num = 0;
+       spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+       usb_kill_urb(port->interrupt_in_urb);
+       dev_dbg(&port->dev, "%s - usb_reset_device\n", __func__);
+       status = usb_reset_device(port->serial->dev);
+       if (status)
+               dev_dbg(&port->dev, "%s - usb_reset_device failed: %d\n",
+                       __func__, status);
+       return status;
+}
+
+
+
+/*
+ * clear all cached data
+ */
+static int garmin_clear(struct garmin_data *garmin_data_p)
+{
+       unsigned long flags;
+       int status = 0;
+
+       /* flush all queued data */
+       pkt_clear(garmin_data_p);
+
+       spin_lock_irqsave(&garmin_data_p->lock, flags);
+       garmin_data_p->insize = 0;
+       garmin_data_p->outsize = 0;
+       spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+       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;
+       int i = 0;
+
+       if (status == 0) {
+               usb_kill_urb(port->interrupt_in_urb);
+
+               dev_dbg(&serial->dev->dev, "%s - adding interrupt input\n", __func__);
+               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",
+                                                       __func__, status);
+       }
+
+       /*
+        * using the initialization method from gpsbabel. See comments in
+        * gpsbabel/jeeps/gpslibusb.c gusb_reset_toggles()
+        */
+       if (status == 0) {
+               dev_dbg(&serial->dev->dev, "%s - starting session ...\n", __func__);
+               garmin_data_p->state = STATE_ACTIVE;
+
+               for (i = 0; i < 3; i++) {
+                       status = garmin_write_bulk(port,
+                                       GARMIN_START_SESSION_REQ,
+                                       sizeof(GARMIN_START_SESSION_REQ), 0);
+
+                       if (status < 0)
+                               break;
+               }
+
+               if (status > 0)
+                       status = 0;
+       }
+
+       return status;
+}
+
+
+
+static int garmin_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+       unsigned long flags;
+       int status = 0;
+       struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
+
+       spin_lock_irqsave(&garmin_data_p->lock, flags);
+       garmin_data_p->mode  = initial_mode;
+       garmin_data_p->count = 0;
+       garmin_data_p->flags &= FLAGS_SESSION_REPLY1_SEEN;
+       spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+       /* 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 garmin_data *garmin_data_p = usb_get_serial_port_data(port);
+
+       dev_dbg(&port->dev, "%s - mode=%d state=%d flags=0x%X\n",
+               __func__, garmin_data_p->mode, garmin_data_p->state,
+               garmin_data_p->flags);
+
+       garmin_clear(garmin_data_p);
+
+       /* shutdown our urbs */
+       usb_kill_urb(port->read_urb);
+       usb_kill_urb(port->write_urb);
+
+       /* keep reset state so we know that we must start a new session */
+       if (garmin_data_p->state != STATE_RESET)
+               garmin_data_p->state = STATE_DISCONNECTED;
+}
+
+
+static void garmin_write_bulk_callback(struct urb *urb)
+{
+       struct usb_serial_port *port = urb->context;
+
+       if (port) {
+               struct garmin_data *garmin_data_p =
+                                       usb_get_serial_port_data(port);
+
+               if (GARMIN_LAYERID_APPL == getLayerId(urb->transfer_buffer)) {
+
+                       if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
+                               gsp_send_ack(garmin_data_p,
+                                       ((__u8 *)urb->transfer_buffer)[4]);
+                       }
+               }
+               usb_serial_port_softint(port);
+       }
+
+       /* Ignore errors that resulted from garmin_write_bulk with
+          dismiss_ack = 1 */
+
+       /* free up the transfer buffer, as usb_free_urb() does not do this */
+       kfree(urb->transfer_buffer);
+}
+
+
+static int garmin_write_bulk(struct usb_serial_port *port,
+                             const unsigned char *buf, int count,
+                             int dismiss_ack)
+{
+       unsigned long flags;
+       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;
+
+       spin_lock_irqsave(&garmin_data_p->lock, flags);
+       garmin_data_p->flags &= ~FLAGS_DROP_DATA;
+       spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+       buffer = kmalloc(count, GFP_ATOMIC);
+       if (!buffer)
+               return -ENOMEM;
+
+       urb = usb_alloc_urb(0, GFP_ATOMIC);
+       if (!urb) {
+               kfree(buffer);
+               return -ENOMEM;
+       }
+
+       memcpy(buffer, buf, count);
+
+       usb_serial_debug_data(&port->dev, __func__, count, buffer);
+
+       usb_fill_bulk_urb(urb, serial->dev,
+                               usb_sndbulkpipe(serial->dev,
+                                       port->bulk_out_endpointAddress),
+                               buffer, count,
+                               garmin_write_bulk_callback,
+                               dismiss_ack ? NULL : port);
+       urb->transfer_flags |= URB_ZERO_PACKET;
+
+       if (GARMIN_LAYERID_APPL == getLayerId(buffer)) {
+
+               spin_lock_irqsave(&garmin_data_p->lock, flags);
+               garmin_data_p->flags |= APP_REQ_SEEN;
+               spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+               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",
+                               __func__, status);
+               count = status;
+       }
+
+       /* 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 tty_struct *tty, struct usb_serial_port *port,
+                                        const unsigned char *buf, int count)
+{
+       struct device *dev = &port->dev;
+       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(dev, __func__, count, buf);
+
+       if (garmin_data_p->state == STATE_RESET)
+               return -EIO;
+
+       /* 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)) {
+
+                       dev_dbg(dev, "%s - processing private request %d\n",
+                               __func__, pktid);
+
+                       /* drop all unfinished transfers */
+                       garmin_clear(garmin_data_p);
+
+                       switch (pktid) {
+                       case PRIV_PKTID_SET_MODE:
+                               if (pktsiz != 4)
+                                       return -EINVPKT;
+                               garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
+                               dev_dbg(dev, "%s - mode set to %d\n",
+                                       __func__, garmin_data_p->mode);
+                               break;
+
+                       case PRIV_PKTID_INFO_REQ:
+                               priv_status_resp(port);
+                               break;
+
+                       case PRIV_PKTID_RESET_REQ:
+                               process_resetdev_request(port);
+                               break;
+
+                       case PRIV_PKTID_SET_DEF_MODE:
+                               if (pktsiz != 4)
+                                       return -EINVPKT;
+                               initial_mode = __le32_to_cpu(privpkt[3]);
+                               dev_dbg(dev, "%s - initial_mode set to %d\n",
+                                       __func__,
+                                       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 tty_struct *tty)
+{
+       struct usb_serial_port *port = tty->driver_data;
+       /*
+        * 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 void garmin_read_process(struct garmin_data *garmin_data_p,
+                                unsigned char *data, unsigned data_length,
+                                int bulk_data)
+{
+       unsigned long flags;
+
+       if (garmin_data_p->flags & FLAGS_DROP_DATA) {
+               /* abort-transfer cmd is active */
+               dev_dbg(&garmin_data_p->port->dev, "%s - pkt dropped\n", __func__);
+       } else if (garmin_data_p->state != STATE_DISCONNECTED &&
+               garmin_data_p->state != STATE_RESET) {
+
+               /* if throttling is active or postprecessing is required
+                  put the received data in the 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 (bulk_data ||
+                          getLayerId(data) == GARMIN_LAYERID_APPL) {
+
+                       spin_lock_irqsave(&garmin_data_p->lock, flags);
+                       garmin_data_p->flags |= APP_RESP_SEEN;
+                       spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+                       if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
+                               pkt_add(garmin_data_p, data, data_length);
+                       } else {
+                               send_to_tty(garmin_data_p->port, data,
+                                               data_length);
+                       }
+               }
+               /* ignore system layer packets ... */
+       }
+}
+
+
+static void garmin_read_bulk_callback(struct urb *urb)
+{
+       unsigned long flags;
+       struct usb_serial_port *port = urb->context;
+       struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
+       unsigned char *data = urb->transfer_buffer;
+       int status = urb->status;
+       int retval;
+
+       if (status) {
+               dev_dbg(&urb->dev->dev, "%s - nonzero read bulk status received: %d\n",
+                       __func__, status);
+               return;
+       }
+
+       usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
+
+       garmin_read_process(garmin_data_p, data, urb->actual_length, 1);
+
+       if (urb->actual_length == 0 &&
+                       0 != (garmin_data_p->flags & FLAGS_BULK_IN_RESTART)) {
+               spin_lock_irqsave(&garmin_data_p->lock, flags);
+               garmin_data_p->flags &= ~FLAGS_BULK_IN_RESTART;
+               spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+               retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
+               if (retval)
+                       dev_err(&port->dev,
+                               "%s - failed resubmitting read urb, error %d\n",
+                               __func__, retval);
+       } else if (urb->actual_length > 0) {
+               /* Continue trying to read until nothing more is received  */
+               if (0 == (garmin_data_p->flags & FLAGS_THROTTLED)) {
+                       retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
+                       if (retval)
+                               dev_err(&port->dev,
+                                       "%s - failed resubmitting read urb, error %d\n",
+                                       __func__, retval);
+               }
+       } else {
+               dev_dbg(&port->dev, "%s - end of bulk data\n", __func__);
+               spin_lock_irqsave(&garmin_data_p->lock, flags);
+               garmin_data_p->flags &= ~FLAGS_BULK_IN_ACTIVE;
+               spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+       }
+}
+
+
+static void garmin_read_int_callback(struct urb *urb)
+{
+       unsigned long flags;
+       int retval;
+       struct usb_serial_port *port = urb->context;
+       struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
+       unsigned char *data = urb->transfer_buffer;
+       int status = urb->status;
+
+       switch (status) {
+       case 0:
+               /* success */
+               break;
+       case -ECONNRESET:
+       case -ENOENT:
+       case -ESHUTDOWN:
+               /* this urb is terminated, clean up */
+               dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
+                       __func__, status);
+               return;
+       default:
+               dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
+                       __func__, status);
+               return;
+       }
+
+       usb_serial_debug_data(&port->dev, __func__, 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))) {
+
+               dev_dbg(&port->dev, "%s - bulk data available.\n", __func__);
+
+               if (0 == (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
+
+                       /* bulk data available */
+                       retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
+                       if (retval) {
+                               dev_err(&port->dev,
+                                "%s - failed submitting read urb, error %d\n",
+                                                       __func__, retval);
+                       } else {
+                               spin_lock_irqsave(&garmin_data_p->lock, flags);
+                               garmin_data_p->flags |= FLAGS_BULK_IN_ACTIVE;
+                               spin_unlock_irqrestore(&garmin_data_p->lock,
+                                                                       flags);
+                       }
+               } else {
+                       /* bulk-in transfer still active */
+                       spin_lock_irqsave(&garmin_data_p->lock, flags);
+                       garmin_data_p->flags |= FLAGS_BULK_IN_RESTART;
+                       spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+               }
+
+       } else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
+                        && 0 == memcmp(data, GARMIN_START_SESSION_REPLY,
+                                       sizeof(GARMIN_START_SESSION_REPLY))) {
+
+               spin_lock_irqsave(&garmin_data_p->lock, flags);
+               garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
+               spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+
+               /* save the serial number */
+               garmin_data_p->serial_num = __le32_to_cpup(
+                                       (__le32 *)(data+GARMIN_PKTHDR_LENGTH));
+
+               dev_dbg(&port->dev, "%s - start-of-session reply seen - serial %u.\n",
+                       __func__, garmin_data_p->serial_num);
+       }
+
+       garmin_read_process(garmin_data_p, data, urb->actual_length, 0);
+
+       retval = usb_submit_urb(urb, GFP_ATOMIC);
+       if (retval)
+               dev_err(&urb->dev->dev,
+                       "%s - Error %d submitting interrupt urb\n",
+                       __func__, retval);
+}
+
+
+/*
+ * 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)
+{
+       unsigned long flags;
+       struct garmin_packet *pkt;
+
+       if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
+               pkt = pkt_pop(garmin_data_p);
+               if (pkt != NULL) {
+                       send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
+                       kfree(pkt);
+                       mod_timer(&garmin_data_p->timer, (1)+jiffies);
+
+               } else {
+                       spin_lock_irqsave(&garmin_data_p->lock, flags);
+                       garmin_data_p->flags &= ~FLAGS_QUEUING;
+                       spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+               }
+       }
+       return 0;
+}
+
+
+static void garmin_throttle(struct tty_struct *tty)
+{
+       struct usb_serial_port *port = tty->driver_data;
+       struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
+
+       /* set flag, data received will be put into a queue
+          for later processing */
+       spin_lock_irq(&garmin_data_p->lock);
+       garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
+       spin_unlock_irq(&garmin_data_p->lock);
+}
+
+
+static void garmin_unthrottle(struct tty_struct *tty)
+{
+       struct usb_serial_port *port = tty->driver_data;
+       struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
+       int status;
+
+       spin_lock_irq(&garmin_data_p->lock);
+       garmin_data_p->flags &= ~FLAGS_THROTTLED;
+       spin_unlock_irq(&garmin_data_p->lock);
+
+       /* 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);
+
+       if (0 != (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
+               status = usb_submit_urb(port->read_urb, GFP_KERNEL);
+               if (status)
+                       dev_err(&port->dev,
+                               "%s - failed resubmitting read urb, error %d\n",
+                               __func__, status);
+       }
+}
+
+/*
+ * 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_port_probe(struct usb_serial_port *port)
+{
+       int status;
+       struct garmin_data *garmin_data_p;
+
+       garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
+       if (!garmin_data_p)
+               return -ENOMEM;
+
+       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->flags = 0;
+       garmin_data_p->count = 0;
+       usb_set_serial_port_data(port, garmin_data_p);
+
+       status = garmin_init_session(port);
+
+       return status;
+}
+
+
+static int garmin_port_remove(struct usb_serial_port *port)
+{
+       struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
+
+       usb_kill_urb(port->interrupt_in_urb);
+       del_timer_sync(&garmin_data_p->timer);
+       kfree(garmin_data_p);
+       return 0;
+}
+
+
+/* All of the device info needed */
+static struct usb_serial_driver garmin_device = {
+       .driver = {
+               .owner       = THIS_MODULE,
+               .name        = "garmin_gps",
+       },
+       .description         = "Garmin GPS usb/tty",
+       .id_table            = id_table,
+       .num_ports           = 1,
+       .open                = garmin_open,
+       .close               = garmin_close,
+       .throttle            = garmin_throttle,
+       .unthrottle          = garmin_unthrottle,
+       .port_probe             = garmin_port_probe,
+       .port_remove            = garmin_port_remove,
+       .write               = garmin_write,
+       .write_room          = garmin_write_room,
+       .write_bulk_callback = garmin_write_bulk_callback,
+       .read_bulk_callback  = garmin_read_bulk_callback,
+       .read_int_callback   = garmin_read_int_callback,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+       &garmin_device, NULL
+};
+
+module_usb_serial_driver(serial_drivers, id_table);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+module_param(initial_mode, int, S_IRUGO);
+MODULE_PARM_DESC(initial_mode, "Initial mode");