xref: /linux/drivers/usb/serial/garmin_gps.c (revision de2fe5e07d58424bc286fff3fd3c1b0bf933cd58)
1 /*
2  * Garmin GPS driver
3  *
4  * Copyright (C) 2004 Hermann Kneissel herkne@users.sourceforge.net
5  *
6  * The latest version of the driver can be found at
7  * http://sourceforge.net/projects/garmin-gps/
8  *
9  * This driver has been derived from v2.1 of the visor driver.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111 USA
24  */
25 
26 #include <linux/config.h>
27 #include <linux/kernel.h>
28 #include <linux/errno.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/timer.h>
32 #include <linux/tty.h>
33 #include <linux/tty_driver.h>
34 #include <linux/tty_flip.h>
35 #include <linux/module.h>
36 #include <linux/spinlock.h>
37 #include <asm/uaccess.h>
38 #include <linux/usb.h>
39 
40 /* the mode to be set when the port ist opened */
41 static int initial_mode = 1;
42 
43 /* debug flag */
44 static int debug = 0;
45 
46 #include "usb-serial.h"
47 
48 #define GARMIN_VENDOR_ID             0x091E
49 
50 /*
51  * Version Information
52  */
53 
54 #define VERSION_MAJOR	0
55 #define VERSION_MINOR	23
56 
57 #define _STR(s) #s
58 #define _DRIVER_VERSION(a,b) "v" _STR(a) "." _STR(b)
59 #define DRIVER_VERSION _DRIVER_VERSION(VERSION_MAJOR, VERSION_MINOR)
60 #define DRIVER_AUTHOR "hermann kneissel"
61 #define DRIVER_DESC "garmin gps driver"
62 
63 /* error codes returned by the driver */
64 #define EINVPKT	1000	/* invalid packet structure */
65 
66 
67 // size of the header of a packet using the usb protocol
68 #define GARMIN_PKTHDR_LENGTH	12
69 
70 // max. possible size of a packet using the serial protocol
71 #define MAX_SERIAL_PKT_SIZ (3+255+3)
72 
73 // max. possible size of a packet with worst case stuffing
74 #define MAX_SERIAL_PKT_SIZ_STUFFED MAX_SERIAL_PKT_SIZ+256
75 
76 // size of a buffer able to hold a complete (no stuffing) packet
77 // (the document protocol does not contain packets with a larger
78 //  size, but in theory a packet may be 64k+12 bytes - if in
79 //  later protocol versions larger packet sizes occur, this value
80 //  should be increased accordingly, so the input buffer is always
81 //  large enough the store a complete packet inclusive header)
82 #define GPS_IN_BUFSIZ  (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ)
83 
84 // size of a buffer able to hold a complete (incl. stuffing) packet
85 #define GPS_OUT_BUFSIZ (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ_STUFFED)
86 
87 // where to place the packet id of a serial packet, so we can
88 // prepend the usb-packet header without the need to move the
89 // packets data
90 #define GSP_INITIAL_OFFSET (GARMIN_PKTHDR_LENGTH-2)
91 
92 // max. size of incoming private packets (header+1 param)
93 #define PRIVPKTSIZ (GARMIN_PKTHDR_LENGTH+4)
94 
95 #define GARMIN_LAYERID_TRANSPORT  0
96 #define GARMIN_LAYERID_APPL      20
97 // our own layer-id to use for some control mechanisms
98 #define GARMIN_LAYERID_PRIVATE	0x01106E4B
99 
100 #define GARMIN_PKTID_PVT_DATA	51
101 #define GARMIN_PKTID_L001_COMMAND_DATA 10
102 
103 #define CMND_ABORT_TRANSFER 0
104 
105 // packet ids used in private layer
106 #define PRIV_PKTID_SET_DEBUG	1
107 #define PRIV_PKTID_SET_MODE	2
108 #define PRIV_PKTID_INFO_REQ	3
109 #define PRIV_PKTID_INFO_RESP	4
110 #define PRIV_PKTID_RESET_REQ	5
111 #define PRIV_PKTID_SET_DEF_MODE	6
112 
113 
114 #define ETX	0x03
115 #define DLE	0x10
116 #define ACK	0x06
117 #define NAK	0x15
118 
119 /* structure used to queue incoming packets */
120 struct garmin_packet {
121 	struct list_head  list;
122 	int               seq;
123 	int               size; // the real size of the data array, always > 0
124 	__u8              data[1];
125 };
126 
127 /* structure used to keep the current state of the driver */
128 struct garmin_data {
129 	__u8   state;
130 	__u16  flags;
131 	__u8   mode;
132 	__u8   ignorePkts;
133 	__u8   count;
134 	__u8   pkt_id;
135 	__u32  serial_num;
136 	struct timer_list timer;
137 	struct usb_serial_port *port;
138 	int    seq_counter;
139 	int    insize;
140 	int    outsize;
141 	__u8   inbuffer [GPS_IN_BUFSIZ];  /* tty -> usb */
142 	__u8   outbuffer[GPS_OUT_BUFSIZ]; /* usb -> tty */
143 	__u8   privpkt[4*6];
144 	spinlock_t lock;
145 	struct list_head pktlist;
146 };
147 
148 
149 #define STATE_NEW            0
150 #define STATE_INITIAL_DELAY  1
151 #define STATE_TIMEOUT        2
152 #define STATE_SESSION_REQ1   3
153 #define STATE_SESSION_REQ2   4
154 #define STATE_ACTIVE         5
155 
156 #define STATE_RESET	     8
157 #define STATE_DISCONNECTED   9
158 #define STATE_WAIT_TTY_ACK  10
159 #define STATE_GSP_WAIT_DATA 11
160 
161 #define MODE_NATIVE          0
162 #define MODE_GARMIN_SERIAL   1
163 
164 // Flags used in garmin_data.flags:
165 #define FLAGS_SESSION_REPLY_MASK  0x00C0
166 #define FLAGS_SESSION_REPLY1_SEEN 0x0080
167 #define FLAGS_SESSION_REPLY2_SEEN 0x0040
168 #define FLAGS_BULK_IN_ACTIVE      0x0020
169 #define FLAGS_THROTTLED           0x0010
170 #define CLEAR_HALT_REQUIRED       0x0001
171 
172 #define FLAGS_QUEUING             0x0100
173 #define FLAGS_APP_RESP_SEEN       0x0200
174 #define FLAGS_APP_REQ_SEEN        0x0400
175 #define FLAGS_DROP_DATA           0x0800
176 
177 #define FLAGS_GSP_SKIP            0x1000
178 #define FLAGS_GSP_DLESEEN         0x2000
179 
180 
181 
182 
183 
184 
185 /* function prototypes */
186 static void gsp_next_packet(struct garmin_data * garmin_data_p);
187 static int  garmin_write_bulk(struct usb_serial_port *port,
188 			     const unsigned char *buf, int count);
189 
190 /* some special packets to be send or received */
191 static unsigned char const GARMIN_START_SESSION_REQ[]
192 	= { 0, 0, 0, 0,  5, 0, 0, 0, 0, 0, 0, 0 };
193 static unsigned char const GARMIN_START_SESSION_REQ2[]
194 	= { 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0 };
195 static unsigned char const GARMIN_START_SESSION_REPLY[]
196 	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
197 static unsigned char const GARMIN_SESSION_ACTIVE_REPLY[]
198 	= { 0, 0, 0, 0, 17, 0, 0, 0, 4, 0, 0, 0, 0, 16, 0, 0 };
199 static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
200 	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
201 static unsigned char const GARMIN_APP_LAYER_REPLY[]
202 	= { 0x14, 0, 0, 0 };
203 static unsigned char const GARMIN_START_PVT_REQ[]
204 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
205 static unsigned char const GARMIN_STOP_PVT_REQ[]
206 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
207 static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
208 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
209 static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
210 	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
211 static unsigned char const PRIVATE_REQ[]
212 	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };
213 
214 
215 
216 static struct usb_device_id id_table [] = {
217 	/* the same device id seems to be used by all usb enabled gps devices */
218 	{ USB_DEVICE(GARMIN_VENDOR_ID, 3 ) },
219 	{ }					/* Terminating entry */
220 };
221 
222 MODULE_DEVICE_TABLE (usb, id_table);
223 
224 static struct usb_driver garmin_driver = {
225 	.name =		"garmin_gps",
226 	.probe =	usb_serial_probe,
227 	.disconnect =	usb_serial_disconnect,
228 	.id_table =	id_table,
229 	.no_dynamic_id = 	1,
230 };
231 
232 
233 static inline int noResponseFromAppLayer(struct garmin_data * garmin_data_p)
234 {
235 	return ((garmin_data_p->flags
236 				& (FLAGS_APP_REQ_SEEN|FLAGS_APP_RESP_SEEN))
237 	        == FLAGS_APP_REQ_SEEN);
238 }
239 
240 
241 static inline int getLayerId(const __u8 *usbPacket)
242 {
243 	return __le32_to_cpup((__le32 *)(usbPacket));
244 }
245 
246 static inline int getPacketId(const __u8 *usbPacket)
247 {
248 	return __le32_to_cpup((__le32 *)(usbPacket+4));
249 }
250 
251 static inline int getDataLength(const __u8 *usbPacket)
252 {
253 	return __le32_to_cpup((__le32 *)(usbPacket+8));
254 }
255 
256 
257 /*
258  * check if the usb-packet in buf contains an abort-transfer command.
259  * (if yes, all queued data will be dropped)
260  */
261 static inline int isAbortTrfCmnd(const unsigned char *buf)
262 {
263 	if (0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ,
264 	                sizeof(GARMIN_STOP_TRANSFER_REQ)) ||
265 	    0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2,
266 	                sizeof(GARMIN_STOP_TRANSFER_REQ_V2)))
267 		return 1;
268 	else
269 		return 0;
270 }
271 
272 
273 
274 static void send_to_tty(struct usb_serial_port *port,
275                         char *data, unsigned int actual_length)
276 {
277 	struct tty_struct *tty = port->tty;
278 
279 	if (tty && actual_length) {
280 
281 		usb_serial_debug_data(debug, &port->dev,
282 					__FUNCTION__, actual_length, data);
283 
284 		tty_buffer_request_room(tty, actual_length);
285 		tty_insert_flip_string(tty, data, actual_length);
286 		tty_flip_buffer_push(tty);
287 	}
288 }
289 
290 
291 /******************************************************************************
292  * packet queue handling
293  ******************************************************************************/
294 
295 /*
296  * queue a received (usb-)packet for later processing
297  */
298 static int pkt_add(struct garmin_data * garmin_data_p,
299                    unsigned char *data, unsigned int data_length)
300 {
301 	int result = 0;
302 	unsigned long flags;
303 	struct garmin_packet *pkt;
304 
305 	/* process only packets containg data ... */
306 	if (data_length) {
307 		garmin_data_p->flags |= FLAGS_QUEUING;
308 		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
309 		              GFP_ATOMIC);
310 		if (pkt == NULL) {
311 			dev_err(&garmin_data_p->port->dev, "out of memory\n");
312 			return 0;
313 		}
314 		pkt->size = data_length;
315 		memcpy(pkt->data, data, data_length);
316 
317 		spin_lock_irqsave(&garmin_data_p->lock, flags);
318 		result = list_empty(&garmin_data_p->pktlist);
319 		pkt->seq = garmin_data_p->seq_counter++;
320 		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
321 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
322 
323 		/* in serial mode, if someone is waiting for data from
324 		   the device, iconvert and send the next packet to tty. */
325 		if (result && (garmin_data_p->state == STATE_GSP_WAIT_DATA)) {
326 			gsp_next_packet(garmin_data_p);
327 		}
328 	}
329 	return result;
330 }
331 
332 
333 /* get the next pending packet */
334 static struct garmin_packet *pkt_pop(struct garmin_data * garmin_data_p)
335 {
336 	unsigned long flags;
337 	struct garmin_packet *result = NULL;
338 
339 	spin_lock_irqsave(&garmin_data_p->lock, flags);
340 	if (!list_empty(&garmin_data_p->pktlist)) {
341 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
342 		list_del(&result->list);
343 	}
344 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
345 	return result;
346 }
347 
348 
349 /* free up all queued data */
350 static void pkt_clear(struct garmin_data * garmin_data_p)
351 {
352 	unsigned long flags;
353 	struct garmin_packet *result = NULL;
354 
355 	dbg("%s", __FUNCTION__);
356 
357 	spin_lock_irqsave(&garmin_data_p->lock, flags);
358 	while (!list_empty(&garmin_data_p->pktlist)) {
359 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
360 		list_del(&result->list);
361 		kfree(result);
362 	}
363 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
364 }
365 
366 
367 /******************************************************************************
368  * garmin serial protocol handling handling
369  ******************************************************************************/
370 
371 /* send an ack packet back to the tty */
372 static int gsp_send_ack(struct garmin_data * garmin_data_p, __u8 pkt_id)
373 {
374 	__u8 pkt[10];
375         __u8 cksum = 0;
376         __u8 *ptr = pkt;
377         unsigned  l = 0;
378 
379 	dbg("%s - pkt-id: 0x%X.", __FUNCTION__, 0xFF & pkt_id);
380 
381 	*ptr++ = DLE;
382 	*ptr++ = ACK;
383 	cksum += ACK;
384 
385 	*ptr++ = 2;
386 	cksum += 2;
387 
388 	*ptr++ = pkt_id;
389 	cksum += pkt_id;
390 
391 	if (pkt_id == DLE) {
392 		*ptr++ = DLE;
393 	}
394 
395 	*ptr++ = 0;
396 	*ptr++ = 0xFF & (-cksum);
397 	*ptr++ = DLE;
398 	*ptr++ = ETX;
399 
400 	l = ptr-pkt;
401 
402 	send_to_tty(garmin_data_p->port, pkt, l);
403 	return 0;
404 }
405 
406 
407 
408 /*
409  * called for a complete packet received from tty layer
410  *
411  * the complete packet (pkzid ... cksum) is in garmin_data_p->inbuf starting
412  * at GSP_INITIAL_OFFSET.
413  *
414  * count - number of bytes in the input buffer including space reserved for
415  *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet
416  *         (including pkt-id, data-length a. cksum)
417  */
418 static int gsp_rec_packet(struct garmin_data * garmin_data_p, int count)
419 {
420 	const __u8* recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
421         __le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;
422 
423 	int cksum = 0;
424 	int n = 0;
425 	int pktid = recpkt[0];
426 	int size = recpkt[1];
427 
428 	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
429 			       __FUNCTION__, count-GSP_INITIAL_OFFSET, recpkt);
430 
431 	if (size != (count-GSP_INITIAL_OFFSET-3)) {
432 		dbg("%s - invalid size, expected %d bytes, got %d",
433 			__FUNCTION__, size, (count-GSP_INITIAL_OFFSET-3));
434 		return -EINVPKT;
435 	}
436 
437 	cksum += *recpkt++;
438 	cksum += *recpkt++;
439 
440 	// sanity check, remove after test ...
441 	if ((__u8*)&(usbdata[3]) != recpkt) {
442 		dbg("%s - ptr mismatch %p - %p",
443 			__FUNCTION__, &(usbdata[4]), recpkt);
444 		return -EINVPKT;
445 	}
446 
447 	while (n < size) {
448 		cksum += *recpkt++;
449 		n++;
450 	}
451 
452        if ((0xff & (cksum + *recpkt)) != 0) {
453                 dbg("%s - invalid checksum, expected %02x, got %02x",
454                         __FUNCTION__, 0xff & -cksum, 0xff & *recpkt);
455                 return -EINVPKT;
456         }
457 
458 	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
459 	usbdata[1] = __cpu_to_le32(pktid);
460 	usbdata[2] = __cpu_to_le32(size);
461 
462 	garmin_write_bulk (garmin_data_p->port, garmin_data_p->inbuffer,
463 			   GARMIN_PKTHDR_LENGTH+size);
464 
465 	/* if this was an abort-transfer command, flush all
466 	   queued data. */
467 	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
468 		garmin_data_p->flags |= FLAGS_DROP_DATA;
469 		pkt_clear(garmin_data_p);
470 	}
471 
472 	return count;
473 }
474 
475 
476 
477 /*
478  * Called for data received from tty
479  *
480  * buf contains the data read, it may span more than one packet or even
481  * incomplete packets
482  *
483  * input record should be a serial-record, but it may not be complete.
484  * Copy it into our local buffer, until an etx is seen (or an error
485  * occurs).
486  * Once the record is complete, convert into a usb packet and send it
487  * to the bulk pipe, send an ack back to the tty.
488  *
489  * If the input is an ack, just send the last queued packet to the
490  * tty layer.
491  *
492  * if the input is an abort command, drop all queued data.
493  */
494 
495 static int gsp_receive(struct garmin_data * garmin_data_p,
496                        const unsigned char *buf, int count)
497 {
498 	int offs = 0;
499 	int ack_or_nak_seen = 0;
500 	int i = 0;
501 	__u8 *dest = garmin_data_p->inbuffer;
502 	int size = garmin_data_p->insize;
503 	// dleSeen: set if last byte read was a DLE
504 	int dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
505 	// skip: if set, skip incoming data until possible start of
506 	//       new packet
507 	int skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
508 	__u8 data;
509 
510 	dbg("%s - dle=%d skip=%d size=%d count=%d",
511 		__FUNCTION__, dleSeen, skip, size, count);
512 
513 	if (size == 0) {
514 		size = GSP_INITIAL_OFFSET;
515 	}
516 
517 	while (offs < count) {
518 
519 		data = *(buf+offs);
520 		offs ++;
521 
522 		if (data == DLE) {
523 			if (skip) { /* start of a new pkt */
524 				skip = 0;
525 				size = GSP_INITIAL_OFFSET;
526 				dleSeen = 1;
527 			} else if (dleSeen) {
528 				dest[size++] = data;
529 				dleSeen = 0;
530 			} else {
531 				dleSeen = 1;
532 			}
533 		} else if (data == ETX) {
534 			if (dleSeen) {
535 				/* packet complete */
536 
537 				data = dest[GSP_INITIAL_OFFSET];
538 
539 				if (data == ACK) {
540 					ack_or_nak_seen = ACK;
541 					dbg("ACK packet complete.");
542 				} else if (data == NAK) {
543 					ack_or_nak_seen = NAK;
544 					dbg("NAK packet complete.");
545 				} else {
546 					dbg("packet complete "
547 						        "- id=0x%X.",
548 						        0xFF & data);
549 					gsp_rec_packet(garmin_data_p, size);
550 				}
551 
552 				skip = 1;
553 				size = GSP_INITIAL_OFFSET;
554 				dleSeen = 0;
555 			} else {
556 				dest[size++] = data;
557 			}
558 		} else if (!skip) {
559 
560 			if (dleSeen) {
561 				dbg("non-masked DLE at %d - restarting", i);
562 				size = GSP_INITIAL_OFFSET;
563 				dleSeen = 0;
564 			}
565 
566 			dest[size++] = data;
567 		}
568 
569 		if (size >= GPS_IN_BUFSIZ) {
570 			dbg("%s - packet too large.", __FUNCTION__);
571 			skip = 1;
572 			size = GSP_INITIAL_OFFSET;
573 			dleSeen = 0;
574 		}
575 	}
576 
577 	garmin_data_p->insize = size;
578 
579 	// copy flags back to structure
580 	if (skip)
581 		garmin_data_p->flags |= FLAGS_GSP_SKIP;
582 	else
583 		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;
584 
585 	if (dleSeen)
586 		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
587 	else
588 		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;
589 
590 	if (ack_or_nak_seen) {
591 		garmin_data_p->state = STATE_GSP_WAIT_DATA;
592 		gsp_next_packet(garmin_data_p);
593 	}
594 
595 	return count;
596 }
597 
598 
599 
600 
601 /*
602  * Sends a usb packet to the tty
603  *
604  * Assumes, that all packages and at an usb-packet boundary.
605  *
606  * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
607  */
608 static int gsp_send(struct garmin_data * garmin_data_p,
609 		    const unsigned char *buf, int count)
610 {
611 	const unsigned char *src;
612 	unsigned char *dst;
613 	int pktid = 0;
614 	int datalen = 0;
615 	int cksum = 0;
616 	int i=0;
617 	int k;
618 
619 	dbg("%s - state %d - %d bytes.", __FUNCTION__,
620 	         garmin_data_p->state, count);
621 
622 	k = garmin_data_p->outsize;
623 	if ((k+count) > GPS_OUT_BUFSIZ) {
624 		dbg("packet too large");
625 		garmin_data_p->outsize = 0;
626 		return -4;
627 	}
628 
629 	memcpy(garmin_data_p->outbuffer+k, buf, count);
630 	k += count;
631 	garmin_data_p->outsize = k;
632 
633 	if (k >= GARMIN_PKTHDR_LENGTH) {
634 		pktid  = getPacketId(garmin_data_p->outbuffer);
635 		datalen= getDataLength(garmin_data_p->outbuffer);
636 		i = GARMIN_PKTHDR_LENGTH + datalen;
637 		if (k < i)
638 			return 0;
639 	} else {
640 		return 0;
641 	}
642 
643 	dbg("%s - %d bytes in buffer, %d bytes in pkt.", __FUNCTION__,
644 	         k, i);
645 
646 	/* garmin_data_p->outbuffer now contains a complete packet */
647 
648 	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
649 		                   __FUNCTION__, k, garmin_data_p->outbuffer);
650 
651 	garmin_data_p->outsize = 0;
652 
653 	if (GARMIN_LAYERID_APPL != getLayerId(garmin_data_p->outbuffer)) {
654 		dbg("not an application packet (%d)",
655 		        getLayerId(garmin_data_p->outbuffer));
656 		return -1;
657 	}
658 
659 	if (pktid > 255) {
660 		dbg("packet-id %d too large", pktid);
661 		return -2;
662 	}
663 
664 	if (datalen > 255) {
665 		dbg("packet-size %d too large", datalen);
666 		return -3;
667 	}
668 
669 	/* the serial protocol should be able to handle this packet */
670 
671 	k = 0;
672 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
673 	for (i=0; i<datalen; i++) {
674 		if (*src++ == DLE)
675 			k++;
676 	}
677 
678 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
679 	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
680 		/* can't add stuffing DLEs in place, move data to end
681                    of buffer ... */
682 		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
683 		memcpy(dst, src, datalen);
684 		src = dst;
685 	}
686 
687 	dst = garmin_data_p->outbuffer;
688 
689 	*dst++ = DLE;
690 	*dst++ = pktid;
691 	cksum += pktid;
692 	*dst++ = datalen;
693 	cksum += datalen;
694 	if (datalen == DLE)
695 		*dst++ = DLE;
696 
697 	for (i=0; i<datalen; i++) {
698 		__u8 c = *src++;
699 		*dst++ = c;
700 		cksum += c;
701 		if (c == DLE)
702 			*dst++ = DLE;
703 	}
704 
705 	cksum = 0xFF & -cksum;
706 	*dst++ = cksum;
707 	if (cksum == DLE)
708 		*dst++ = DLE;
709 	*dst++ = DLE;
710 	*dst++ = ETX;
711 
712 	i = dst-garmin_data_p->outbuffer;
713 
714 	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);
715 
716 	garmin_data_p->pkt_id = pktid;
717 	garmin_data_p->state  = STATE_WAIT_TTY_ACK;
718 
719 	return i;
720 }
721 
722 
723 
724 
725 
726 /*
727  * Process the next pending data packet - if there is one
728  */
729 static void gsp_next_packet(struct garmin_data * garmin_data_p)
730 {
731 	struct garmin_packet *pkt = NULL;
732 
733 	while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
734 		dbg("%s - next pkt: %d", __FUNCTION__, pkt->seq);
735 		if (gsp_send(garmin_data_p, pkt->data, pkt->size) > 0) {
736 			kfree(pkt);
737 			return;
738 		}
739 		kfree(pkt);
740 	}
741 }
742 
743 
744 
745 
746 /******************************************************************************
747  * garmin native mode
748  ******************************************************************************/
749 
750 
751 /*
752  * Called for data received from tty
753  *
754  * The input data is expected to be in garmin usb-packet format.
755  *
756  * buf contains the data read, it may span more than one packet
757  * or even incomplete packets
758  */
759 static int nat_receive(struct garmin_data * garmin_data_p,
760                        const unsigned char *buf, int count)
761 {
762 	__u8 * dest;
763 	int offs = 0;
764 	int result = count;
765 	int len;
766 
767 	while (offs < count) {
768 		// if buffer contains header, copy rest of data
769 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
770 			len = GARMIN_PKTHDR_LENGTH
771 			      +getDataLength(garmin_data_p->inbuffer);
772 		else
773 			len = GARMIN_PKTHDR_LENGTH;
774 
775 		if (len >= GPS_IN_BUFSIZ) {
776 			/* seem to be an invalid packet, ignore rest of input */
777 			dbg("%s - packet size too large: %d",
778 			        __FUNCTION__, len);
779 			garmin_data_p->insize = 0;
780 			count = 0;
781 			result = -EINVPKT;
782 		} else {
783 			len -= garmin_data_p->insize;
784 			if (len > (count-offs))
785 				len = (count-offs);
786 			if (len > 0) {
787 				dest = garmin_data_p->inbuffer
788 				       	+garmin_data_p->insize;
789 				memcpy(dest, buf+offs, len);
790 				garmin_data_p->insize += len;
791 				offs += len;
792 			}
793 		}
794 
795 		/* do we have a complete packet ? */
796 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
797 			len = GARMIN_PKTHDR_LENGTH+
798 			   getDataLength(garmin_data_p->inbuffer);
799 			if (garmin_data_p->insize >= len) {
800 				garmin_write_bulk (garmin_data_p->port,
801 				                   garmin_data_p->inbuffer,
802 				                   len);
803 				garmin_data_p->insize = 0;
804 
805 				/* if this was an abort-transfer command,
806 				   flush all queued data. */
807 				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
808 					garmin_data_p->flags |= FLAGS_DROP_DATA;
809 					pkt_clear(garmin_data_p);
810 				}
811 			}
812 		}
813 	}
814 	return result;
815 }
816 
817 
818 /******************************************************************************
819  * private packets
820  ******************************************************************************/
821 
822 static void priv_status_resp(struct usb_serial_port *port)
823 {
824 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
825 	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;
826 
827 	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
828 	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
829 	pkt[2] = __cpu_to_le32(12);
830 	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
831 	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
832 	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);
833 
834 	send_to_tty(port, (__u8*)pkt, 6*4);
835 }
836 
837 
838 /******************************************************************************
839  * Garmin specific driver functions
840  ******************************************************************************/
841 
842 static int process_resetdev_request(struct usb_serial_port *port)
843 {
844 	int status;
845 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
846 
847 	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
848 	garmin_data_p->state = STATE_RESET;
849 	garmin_data_p->serial_num = 0;
850 
851 	usb_kill_urb (port->interrupt_in_urb);
852 	dbg("%s - usb_reset_device", __FUNCTION__ );
853 	status = usb_reset_device(port->serial->dev);
854 	if (status)
855 		dbg("%s - usb_reset_device failed: %d",
856 			__FUNCTION__, status);
857 	return status;
858 }
859 
860 
861 
862 /*
863  * clear all cached data
864  */
865 static int garmin_clear(struct garmin_data * garmin_data_p)
866 {
867 	int status = 0;
868 
869 	struct usb_serial_port *port = garmin_data_p->port;
870 
871 	if (port != NULL && garmin_data_p->flags & FLAGS_APP_RESP_SEEN) {
872 		/* send a terminate command */
873 		status = garmin_write_bulk(port, GARMIN_STOP_TRANSFER_REQ,
874 		                           sizeof(GARMIN_STOP_TRANSFER_REQ));
875 	}
876 
877 	/* flush all queued data */
878 	pkt_clear(garmin_data_p);
879 
880 	garmin_data_p->insize = 0;
881 	garmin_data_p->outsize = 0;
882 
883 	return status;
884 }
885 
886 
887 
888 
889 
890 
891 static int garmin_init_session(struct usb_serial_port *port)
892 {
893 	struct usb_serial *serial = port->serial;
894 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
895 	int status = 0;
896 
897 	if (status == 0) {
898 		usb_kill_urb (port->interrupt_in_urb);
899 
900 		dbg("%s - adding interrupt input", __FUNCTION__);
901 		port->interrupt_in_urb->dev = serial->dev;
902 		status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
903 		if (status)
904 			dev_err(&serial->dev->dev,
905 			        "%s - failed submitting interrupt urb,"
906 				" error %d\n",
907 			        __FUNCTION__, status);
908 	}
909 
910 	if (status == 0) {
911 		dbg("%s - starting session ...", __FUNCTION__);
912 		garmin_data_p->state = STATE_ACTIVE;
913 		status = garmin_write_bulk(port, GARMIN_START_SESSION_REQ,
914 		                           sizeof(GARMIN_START_SESSION_REQ));
915 
916 		if (status >= 0) {
917 
918 			garmin_data_p->ignorePkts++;
919 
920 			/* not needed, but the win32 driver does it too ... */
921 			status = garmin_write_bulk(port,
922 						   GARMIN_START_SESSION_REQ2,
923 			                           sizeof(GARMIN_START_SESSION_REQ2));
924 			if (status >= 0) {
925 				status = 0;
926 				garmin_data_p->ignorePkts++;
927 			}
928 		}
929 	}
930 
931 	return status;
932 }
933 
934 
935 
936 
937 
938 static int garmin_open (struct usb_serial_port *port, struct file *filp)
939 {
940 	int status = 0;
941 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
942 
943 	dbg("%s - port %d", __FUNCTION__, port->number);
944 
945 	/*
946 	 * Force low_latency on so that our tty_push actually forces the data
947 	 * through, otherwise it is scheduled, and with high data rates (like
948 	 * with OHCI) data can get lost.
949 	 */
950 	if (port->tty)
951 		port->tty->low_latency = 1;
952 
953 	garmin_data_p->mode  = initial_mode;
954 	garmin_data_p->count = 0;
955 	garmin_data_p->flags = 0;
956 
957 	/* shutdown any bulk reads that might be going on */
958 	usb_kill_urb (port->write_urb);
959 	usb_kill_urb (port->read_urb);
960 
961 	if (garmin_data_p->state == STATE_RESET) {
962 		status = garmin_init_session(port);
963 	}
964 
965 	garmin_data_p->state = STATE_ACTIVE;
966 
967 	return status;
968 }
969 
970 
971 static void garmin_close (struct usb_serial_port *port, struct file * filp)
972 {
973 	struct usb_serial *serial = port->serial;
974 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
975 
976 	dbg("%s - port %d - mode=%d state=%d flags=0x%X", __FUNCTION__,
977 		port->number, garmin_data_p->mode,
978 		garmin_data_p->state, garmin_data_p->flags);
979 
980 	if (!serial)
981 		return;
982 
983 	garmin_clear(garmin_data_p);
984 
985 	/* shutdown our urbs */
986 	usb_kill_urb (port->read_urb);
987 	usb_kill_urb (port->write_urb);
988 
989 	if (noResponseFromAppLayer(garmin_data_p) ||
990 	    ((garmin_data_p->flags & CLEAR_HALT_REQUIRED) != 0)) {
991 		process_resetdev_request(port);
992 		garmin_data_p->state = STATE_RESET;
993 	} else {
994 		garmin_data_p->state = STATE_DISCONNECTED;
995 	}
996 }
997 
998 
999 static void garmin_write_bulk_callback (struct urb *urb, struct pt_regs *regs)
1000 {
1001 	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
1002 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1003 
1004 	/* free up the transfer buffer, as usb_free_urb() does not do this */
1005 	kfree (urb->transfer_buffer);
1006 
1007 	dbg("%s - port %d", __FUNCTION__, port->number);
1008 
1009 	if (urb->status) {
1010 		dbg("%s - nonzero write bulk status received: %d",
1011 			__FUNCTION__, urb->status);
1012 		garmin_data_p->flags |= CLEAR_HALT_REQUIRED;
1013 	}
1014 
1015 	schedule_work(&port->work);
1016 }
1017 
1018 
1019 static int garmin_write_bulk (struct usb_serial_port *port,
1020                               const unsigned char *buf, int count)
1021 {
1022 	struct usb_serial *serial = port->serial;
1023 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1024 	struct urb *urb;
1025 	unsigned char *buffer;
1026 	int status;
1027 
1028 	dbg("%s - port %d, state %d", __FUNCTION__, port->number,
1029 		garmin_data_p->state);
1030 
1031 	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
1032 
1033 	buffer = kmalloc (count, GFP_ATOMIC);
1034 	if (!buffer) {
1035 		dev_err(&port->dev, "out of memory\n");
1036 		return -ENOMEM;
1037 	}
1038 
1039 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1040 	if (!urb) {
1041 		dev_err(&port->dev, "no more free urbs\n");
1042 		kfree (buffer);
1043 		return -ENOMEM;
1044 	}
1045 
1046 	memcpy (buffer, buf, count);
1047 
1048 	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, buffer);
1049 
1050 	usb_fill_bulk_urb (urb, serial->dev,
1051 			 	usb_sndbulkpipe (serial->dev,
1052 				port->bulk_out_endpointAddress),
1053 				buffer, count,
1054 				garmin_write_bulk_callback, port);
1055 	urb->transfer_flags |= URB_ZERO_PACKET;
1056 
1057 	if (GARMIN_LAYERID_APPL == getLayerId(buffer)) {
1058 		garmin_data_p->flags |= FLAGS_APP_REQ_SEEN;
1059 		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
1060 			pkt_clear(garmin_data_p);
1061 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
1062 		}
1063 	}
1064 
1065 	/* send it down the pipe */
1066 	status = usb_submit_urb(urb, GFP_ATOMIC);
1067 	if (status) {
1068 		dev_err(&port->dev,
1069 		        "%s - usb_submit_urb(write bulk) "
1070 		        "failed with status = %d\n",
1071 				__FUNCTION__, status);
1072 		count = status;
1073 	} else {
1074 
1075 		if (GARMIN_LAYERID_APPL == getLayerId(buffer)
1076 		    && (garmin_data_p->mode == MODE_GARMIN_SERIAL))  {
1077 
1078 			gsp_send_ack(garmin_data_p, buffer[4]);
1079 		}
1080 	}
1081 
1082 	/* we are done with this urb, so let the host driver
1083 	 * really free it when it is finished with it */
1084 	usb_free_urb (urb);
1085 
1086 	return count;
1087 }
1088 
1089 
1090 
1091 static int garmin_write (struct usb_serial_port *port,
1092                          const unsigned char *buf, int count)
1093 {
1094 	int pktid, pktsiz, len;
1095 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1096 	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;
1097 
1098 	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, buf);
1099 
1100 	/* check for our private packets */
1101 	if (count >= GARMIN_PKTHDR_LENGTH) {
1102 
1103 		len = PRIVPKTSIZ;
1104 		if (count < len)
1105 			len = count;
1106 
1107 		memcpy(garmin_data_p->privpkt, buf, len);
1108 
1109 		pktsiz = getDataLength(garmin_data_p->privpkt);
1110 		pktid  = getPacketId(garmin_data_p->privpkt);
1111 
1112 		if (count == (GARMIN_PKTHDR_LENGTH+pktsiz)
1113 		    && GARMIN_LAYERID_PRIVATE == getLayerId(garmin_data_p->privpkt)) {
1114 
1115 			dbg("%s - processing private request %d",
1116 				__FUNCTION__, pktid);
1117 
1118 			// drop all unfinished transfers
1119 			garmin_clear(garmin_data_p);
1120 
1121 			switch(pktid) {
1122 
1123 			case PRIV_PKTID_SET_DEBUG:
1124 				if (pktsiz != 4)
1125 					return -EINVPKT;
1126 				debug = __le32_to_cpu(privpkt[3]);
1127 				dbg("%s - debug level set to 0x%X",
1128 					__FUNCTION__, debug);
1129 				break;
1130 
1131 			case PRIV_PKTID_SET_MODE:
1132 				if (pktsiz != 4)
1133 					return -EINVPKT;
1134 				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
1135 				dbg("%s - mode set to %d",
1136 					__FUNCTION__, garmin_data_p->mode);
1137 				break;
1138 
1139 			case PRIV_PKTID_INFO_REQ:
1140 				priv_status_resp(port);
1141 				break;
1142 
1143 			case PRIV_PKTID_RESET_REQ:
1144 				garmin_data_p->flags |= FLAGS_APP_REQ_SEEN;
1145 				break;
1146 
1147 			case PRIV_PKTID_SET_DEF_MODE:
1148 				if (pktsiz != 4)
1149 					return -EINVPKT;
1150 				initial_mode = __le32_to_cpu(privpkt[3]);
1151 				dbg("%s - initial_mode set to %d",
1152 					__FUNCTION__,
1153 					garmin_data_p->mode);
1154 				break;
1155 			}
1156 			return count;
1157 		}
1158 	}
1159 
1160 	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1161 		return gsp_receive(garmin_data_p, buf, count);
1162 	} else {	/* MODE_NATIVE */
1163 		return nat_receive(garmin_data_p, buf, count);
1164 	}
1165 }
1166 
1167 
1168 static int garmin_write_room (struct usb_serial_port *port)
1169 {
1170 	/*
1171 	 * Report back the bytes currently available in the output buffer.
1172 	 */
1173 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1174 	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
1175 }
1176 
1177 
1178 static int garmin_chars_in_buffer (struct usb_serial_port *port)
1179 {
1180 	/*
1181 	 * Report back the number of bytes currently in our input buffer.
1182          * Will this lock up the driver - the buffer contains an incomplete
1183          * package which will not be written to the device until it
1184          * has been completed ?
1185          */
1186 	//struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1187 	//return garmin_data_p->insize;
1188 	return 0;
1189 }
1190 
1191 
1192 static void garmin_read_process(struct garmin_data * garmin_data_p,
1193 				 unsigned char *data, unsigned data_length)
1194 {
1195 	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
1196 		/* abort-transfer cmd is actice */
1197 		dbg("%s - pkt dropped", __FUNCTION__);
1198 	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
1199 	           garmin_data_p->state != STATE_RESET ) {
1200 
1201 		/* remember any appl.layer packets, so we know
1202 		   if a reset is required or not when closing
1203 		   the device */
1204 		if (0 == memcmp(data, GARMIN_APP_LAYER_REPLY,
1205 		                sizeof(GARMIN_APP_LAYER_REPLY)))
1206 			garmin_data_p->flags |= FLAGS_APP_RESP_SEEN;
1207 
1208 		/* if throttling is active or postprecessing is required
1209 		   put the received data in th input queue, otherwise
1210 		   send it directly to the tty port */
1211 		if (garmin_data_p->flags & FLAGS_QUEUING) {
1212 			pkt_add(garmin_data_p, data, data_length);
1213 		} else if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1214 			if (getLayerId(data) == GARMIN_LAYERID_APPL) {
1215 				pkt_add(garmin_data_p, data, data_length);
1216 			}
1217 		} else {
1218 			send_to_tty(garmin_data_p->port, data, data_length);
1219 		}
1220 	}
1221 }
1222 
1223 
1224 static void garmin_read_bulk_callback (struct urb *urb, struct pt_regs *regs)
1225 {
1226 	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
1227 	struct usb_serial *serial =  port->serial;
1228 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1229 	unsigned char *data = urb->transfer_buffer;
1230 	int status;
1231 
1232 	dbg("%s - port %d", __FUNCTION__, port->number);
1233 
1234 	if (!serial) {
1235 		dbg("%s - bad serial pointer, exiting", __FUNCTION__);
1236 		return;
1237 	}
1238 
1239 	if (urb->status) {
1240 		dbg("%s - nonzero read bulk status received: %d",
1241 			__FUNCTION__, urb->status);
1242 		return;
1243 	}
1244 
1245 	usb_serial_debug_data(debug, &port->dev,
1246 				__FUNCTION__, urb->actual_length, data);
1247 
1248 	garmin_read_process(garmin_data_p, data, urb->actual_length);
1249 
1250 	/* Continue trying to read until nothing more is received  */
1251 	if (urb->actual_length > 0) {
1252 		usb_fill_bulk_urb (port->read_urb, serial->dev,
1253 			   usb_rcvbulkpipe (serial->dev,
1254 					    port->bulk_in_endpointAddress),
1255 			   port->read_urb->transfer_buffer,
1256 			   port->read_urb->transfer_buffer_length,
1257 			   garmin_read_bulk_callback, port);
1258 		status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1259 		if (status)
1260 			dev_err(&port->dev,
1261 				"%s - failed resubmitting read urb, error %d\n",
1262 			        __FUNCTION__, status);
1263 	}
1264 	return;
1265 }
1266 
1267 
1268 static void garmin_read_int_callback (struct urb *urb, struct pt_regs *regs)
1269 {
1270 	int status;
1271 	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
1272 	struct usb_serial *serial = port->serial;
1273 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1274 	unsigned char *data = urb->transfer_buffer;
1275 
1276 	switch (urb->status) {
1277 	case 0:
1278 		/* success */
1279 		break;
1280 	case -ECONNRESET:
1281 	case -ENOENT:
1282 	case -ESHUTDOWN:
1283 		/* this urb is terminated, clean up */
1284 		dbg("%s - urb shutting down with status: %d",
1285 			__FUNCTION__, urb->status);
1286 		return;
1287 	default:
1288 		dbg("%s - nonzero urb status received: %d",
1289 			__FUNCTION__, urb->status);
1290 		return;
1291 	}
1292 
1293 	usb_serial_debug_data(debug, &port->dev, __FUNCTION__,
1294 				urb->actual_length, urb->transfer_buffer);
1295 
1296 	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
1297 	    0 == memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
1298 		        sizeof(GARMIN_BULK_IN_AVAIL_REPLY))) {
1299 
1300 		dbg("%s - bulk data available.", __FUNCTION__);
1301 
1302 		/* bulk data available */
1303 		usb_fill_bulk_urb (port->read_urb, serial->dev,
1304 				usb_rcvbulkpipe (serial->dev,
1305 				port->bulk_in_endpointAddress),
1306 				port->read_urb->transfer_buffer,
1307 				port->read_urb->transfer_buffer_length,
1308 				garmin_read_bulk_callback, port);
1309 		status = usb_submit_urb(port->read_urb, GFP_KERNEL);
1310 		if (status) {
1311 			dev_err(&port->dev,
1312 				"%s - failed submitting read urb, error %d\n",
1313 			__FUNCTION__, status);
1314 		}
1315 
1316 	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
1317 			 && 0 == memcmp(data, GARMIN_START_SESSION_REPLY,
1318 			                sizeof(GARMIN_START_SESSION_REPLY))) {
1319 
1320 		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
1321 
1322 		/* save the serial number */
1323 		garmin_data_p->serial_num
1324 			= __le32_to_cpup((__le32*)(data+GARMIN_PKTHDR_LENGTH));
1325 
1326 		dbg("%s - start-of-session reply seen - serial %u.",
1327 			__FUNCTION__, garmin_data_p->serial_num);
1328 	}
1329 
1330 	if (garmin_data_p->ignorePkts) {
1331 		/* this reply belongs to a request generated by the driver,
1332 		   ignore it. */
1333 		dbg("%s - pkt ignored (%d)",
1334 			__FUNCTION__, garmin_data_p->ignorePkts);
1335 		garmin_data_p->ignorePkts--;
1336 	} else {
1337 		garmin_read_process(garmin_data_p, data, urb->actual_length);
1338 	}
1339 
1340 	port->interrupt_in_urb->dev = port->serial->dev;
1341 	status = usb_submit_urb (urb, GFP_ATOMIC);
1342 	if (status)
1343 		dev_err(&urb->dev->dev,
1344 			"%s - Error %d submitting interrupt urb\n",
1345 			__FUNCTION__, status);
1346 }
1347 
1348 
1349 /*
1350  * Sends the next queued packt to the tty port (garmin native mode only)
1351  * and then sets a timer to call itself again until all queued data
1352  * is sent.
1353  */
1354 static int garmin_flush_queue(struct garmin_data * garmin_data_p)
1355 {
1356 	struct garmin_packet *pkt;
1357 
1358 	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1359 		pkt = pkt_pop(garmin_data_p);
1360 		if (pkt != NULL) {
1361 
1362 			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
1363 			kfree(pkt);
1364 			mod_timer(&garmin_data_p->timer, (1)+jiffies);
1365 
1366 		} else {
1367 			garmin_data_p->flags &= ~FLAGS_QUEUING;
1368 		}
1369 	}
1370 	return 0;
1371 }
1372 
1373 
1374 static void garmin_throttle (struct usb_serial_port *port)
1375 {
1376 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1377 
1378 	dbg("%s - port %d", __FUNCTION__, port->number);
1379 	/* set flag, data received will be put into a queue
1380 	   for later processing */
1381 	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
1382 }
1383 
1384 
1385 static void garmin_unthrottle (struct usb_serial_port *port)
1386 {
1387 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1388 
1389 	dbg("%s - port %d", __FUNCTION__, port->number);
1390 	garmin_data_p->flags &= ~FLAGS_THROTTLED;
1391 
1392 	/* in native mode send queued data to tty, in
1393 	   serial mode nothing needs to be done here */
1394 	if (garmin_data_p->mode == MODE_NATIVE)
1395 		garmin_flush_queue(garmin_data_p);
1396 }
1397 
1398 
1399 
1400 /*
1401  * The timer is currently only used to send queued packets to
1402  * the tty in cases where the protocol provides no own handshaking
1403  * to initiate the transfer.
1404  */
1405 static void timeout_handler(unsigned long data)
1406 {
1407 	struct garmin_data *garmin_data_p = (struct garmin_data *) data;
1408 
1409 	/* send the next queued packet to the tty port */
1410 	if (garmin_data_p->mode == MODE_NATIVE)
1411 		if (garmin_data_p->flags & FLAGS_QUEUING)
1412 			garmin_flush_queue(garmin_data_p);
1413 }
1414 
1415 
1416 
1417 static int garmin_attach (struct usb_serial *serial)
1418 {
1419 	int status = 0;
1420 	struct usb_serial_port *port = serial->port[0];
1421 	struct garmin_data * garmin_data_p = NULL;
1422 
1423 	dbg("%s", __FUNCTION__);
1424 
1425 	garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
1426 	if (garmin_data_p == NULL) {
1427 		dev_err(&port->dev, "%s - Out of memory\n", __FUNCTION__);
1428 		return -ENOMEM;
1429 	}
1430 	init_timer(&garmin_data_p->timer);
1431 	spin_lock_init(&garmin_data_p->lock);
1432 	INIT_LIST_HEAD(&garmin_data_p->pktlist);
1433 	//garmin_data_p->timer.expires = jiffies + session_timeout;
1434 	garmin_data_p->timer.data = (unsigned long)garmin_data_p;
1435 	garmin_data_p->timer.function = timeout_handler;
1436 	garmin_data_p->port = port;
1437 	garmin_data_p->state = 0;
1438 	garmin_data_p->count = 0;
1439 	usb_set_serial_port_data(port, garmin_data_p);
1440 
1441 	status = garmin_init_session(port);
1442 
1443 	return status;
1444 }
1445 
1446 
1447 static void garmin_shutdown (struct usb_serial *serial)
1448 {
1449 	struct usb_serial_port *port = serial->port[0];
1450 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1451 
1452 	dbg("%s", __FUNCTION__);
1453 
1454 	usb_kill_urb (port->interrupt_in_urb);
1455 	del_timer_sync(&garmin_data_p->timer);
1456 	kfree (garmin_data_p);
1457 	usb_set_serial_port_data(port, NULL);
1458 }
1459 
1460 
1461 /* All of the device info needed */
1462 static struct usb_serial_driver garmin_device = {
1463 	.driver = {
1464 		.owner =	THIS_MODULE,
1465 		.name =		"garmin_gps",
1466 	},
1467 	.description =		"Garmin GPS usb/tty",
1468 	.id_table            = id_table,
1469 	.num_interrupt_in    = 1,
1470 	.num_bulk_in         = 1,
1471 	.num_bulk_out        = 1,
1472 	.num_ports           = 1,
1473 	.open                = garmin_open,
1474 	.close               = garmin_close,
1475 	.throttle            = garmin_throttle,
1476 	.unthrottle          = garmin_unthrottle,
1477 	.attach              = garmin_attach,
1478 	.shutdown            = garmin_shutdown,
1479 	.write               = garmin_write,
1480 	.write_room          = garmin_write_room,
1481 	.chars_in_buffer     = garmin_chars_in_buffer,
1482 	.write_bulk_callback = garmin_write_bulk_callback,
1483 	.read_bulk_callback  = garmin_read_bulk_callback,
1484 	.read_int_callback   = garmin_read_int_callback,
1485 };
1486 
1487 
1488 static int __init garmin_init (void)
1489 {
1490 	int retval;
1491 
1492 	retval = usb_serial_register(&garmin_device);
1493 	if (retval)
1494 		goto failed_garmin_register;
1495 	retval = usb_register(&garmin_driver);
1496 	if (retval)
1497 		goto failed_usb_register;
1498 	info(DRIVER_DESC " " DRIVER_VERSION);
1499 
1500 	return 0;
1501 failed_usb_register:
1502 	usb_serial_deregister(&garmin_device);
1503 failed_garmin_register:
1504 	return retval;
1505 }
1506 
1507 
1508 static void __exit garmin_exit (void)
1509 {
1510 	usb_deregister (&garmin_driver);
1511 	usb_serial_deregister (&garmin_device);
1512 }
1513 
1514 
1515 
1516 
1517 module_init(garmin_init);
1518 module_exit(garmin_exit);
1519 
1520 MODULE_AUTHOR( DRIVER_AUTHOR );
1521 MODULE_DESCRIPTION( DRIVER_DESC );
1522 MODULE_LICENSE("GPL");
1523 
1524 module_param(debug, bool, S_IWUSR | S_IRUGO);
1525 MODULE_PARM_DESC(debug, "Debug enabled or not");
1526 module_param(initial_mode, int, S_IRUGO);
1527 MODULE_PARM_DESC(initial_mode, "Initial mode");
1528 
1529