xref: /linux/drivers/usb/serial/garmin_gps.c (revision 7ac9da10af7ffd94cfd07e097b93d588bbd32b75)
1 /*
2  * Garmin GPS driver
3  *
4  * Copyright (C) 2006 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/kernel.h>
27 #include <linux/errno.h>
28 #include <linux/init.h>
29 #include <linux/slab.h>
30 #include <linux/timer.h>
31 #include <linux/tty.h>
32 #include <linux/tty_driver.h>
33 #include <linux/tty_flip.h>
34 #include <linux/module.h>
35 #include <linux/spinlock.h>
36 #include <asm/uaccess.h>
37 #include <linux/usb.h>
38 #include <linux/usb/serial.h>
39 
40 #include <linux/version.h>
41 
42 /* the mode to be set when the port ist opened */
43 static int initial_mode = 1;
44 
45 /* debug flag */
46 static int debug = 0;
47 
48 #define GARMIN_VENDOR_ID             0x091E
49 
50 /*
51  * Version Information
52  */
53 
54 #define VERSION_MAJOR	0
55 #define VERSION_MINOR	28
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_BULK_IN_RESTART     0x0010
170 #define FLAGS_THROTTLED           0x0008
171 #define CLEAR_HALT_REQUIRED       0x0001
172 
173 #define FLAGS_QUEUING             0x0100
174 #define FLAGS_APP_RESP_SEEN       0x0200
175 #define FLAGS_APP_REQ_SEEN        0x0400
176 #define FLAGS_DROP_DATA           0x0800
177 
178 #define FLAGS_GSP_SKIP            0x1000
179 #define FLAGS_GSP_DLESEEN         0x2000
180 
181 
182 
183 
184 
185 
186 /* function prototypes */
187 static void gsp_next_packet(struct garmin_data * garmin_data_p);
188 static int  garmin_write_bulk(struct usb_serial_port *port,
189 			     const unsigned char *buf, int count);
190 
191 /* some special packets to be send or received */
192 static unsigned char const GARMIN_START_SESSION_REQ[]
193 	= { 0, 0, 0, 0,  5, 0, 0, 0, 0, 0, 0, 0 };
194 static unsigned char const GARMIN_START_SESSION_REQ2[]
195 	= { 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0 };
196 static unsigned char const GARMIN_START_SESSION_REPLY[]
197 	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
198 static unsigned char const GARMIN_SESSION_ACTIVE_REPLY[]
199 	= { 0, 0, 0, 0, 17, 0, 0, 0, 4, 0, 0, 0, 0, 16, 0, 0 };
200 static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
201 	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
202 static unsigned char const GARMIN_APP_LAYER_REPLY[]
203 	= { 0x14, 0, 0, 0 };
204 static unsigned char const GARMIN_START_PVT_REQ[]
205 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
206 static unsigned char const GARMIN_STOP_PVT_REQ[]
207 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
208 static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
209 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
210 static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
211 	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
212 static unsigned char const PRIVATE_REQ[]
213 	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };
214 
215 
216 
217 static struct usb_device_id id_table [] = {
218 	/* the same device id seems to be used by all usb enabled gps devices */
219 	{ USB_DEVICE(GARMIN_VENDOR_ID, 3 ) },
220 	{ }					/* Terminating entry */
221 };
222 
223 MODULE_DEVICE_TABLE (usb, id_table);
224 
225 static struct usb_driver garmin_driver = {
226 	.name =		"garmin_gps",
227 	.probe =	usb_serial_probe,
228 	.disconnect =	usb_serial_disconnect,
229 	.id_table =	id_table,
230 	.no_dynamic_id = 1,
231 };
232 
233 
234 static inline int noResponseFromAppLayer(struct garmin_data * garmin_data_p)
235 {
236 	return ((garmin_data_p->flags
237 				& (FLAGS_APP_REQ_SEEN|FLAGS_APP_RESP_SEEN))
238 	        == FLAGS_APP_REQ_SEEN);
239 }
240 
241 
242 static inline int getLayerId(const __u8 *usbPacket)
243 {
244 	return __le32_to_cpup((__le32 *)(usbPacket));
245 }
246 
247 static inline int getPacketId(const __u8 *usbPacket)
248 {
249 	return __le32_to_cpup((__le32 *)(usbPacket+4));
250 }
251 
252 static inline int getDataLength(const __u8 *usbPacket)
253 {
254 	return __le32_to_cpup((__le32 *)(usbPacket+8));
255 }
256 
257 
258 /*
259  * check if the usb-packet in buf contains an abort-transfer command.
260  * (if yes, all queued data will be dropped)
261  */
262 static inline int isAbortTrfCmnd(const unsigned char *buf)
263 {
264 	if (0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ,
265 	                sizeof(GARMIN_STOP_TRANSFER_REQ)) ||
266 	    0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2,
267 	                sizeof(GARMIN_STOP_TRANSFER_REQ_V2)))
268 		return 1;
269 	else
270 		return 0;
271 }
272 
273 
274 
275 static void send_to_tty(struct usb_serial_port *port,
276 			char *data, unsigned int actual_length)
277 {
278 	struct tty_struct *tty = port->tty;
279 
280 	if (tty && actual_length) {
281 
282 		usb_serial_debug_data(debug, &port->dev,
283 					__FUNCTION__, actual_length, data);
284 
285 		tty_buffer_request_room(tty, actual_length);
286 		tty_insert_flip_string(tty, data, actual_length);
287 		tty_flip_buffer_push(tty);
288 	}
289 }
290 
291 
292 /******************************************************************************
293  * packet queue handling
294  ******************************************************************************/
295 
296 /*
297  * queue a received (usb-)packet for later processing
298  */
299 static int pkt_add(struct garmin_data * garmin_data_p,
300 		   unsigned char *data, unsigned int data_length)
301 {
302 	int state = 0;
303 	int result = 0;
304 	unsigned long flags;
305 	struct garmin_packet *pkt;
306 
307 	/* process only packets containg data ... */
308 	if (data_length) {
309 		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
310 		              GFP_ATOMIC);
311 		if (pkt == NULL) {
312 			dev_err(&garmin_data_p->port->dev, "out of memory\n");
313 			return 0;
314 		}
315 		pkt->size = data_length;
316 		memcpy(pkt->data, data, data_length);
317 
318 		spin_lock_irqsave(&garmin_data_p->lock, flags);
319 		garmin_data_p->flags |= FLAGS_QUEUING;
320 		result = list_empty(&garmin_data_p->pktlist);
321 		pkt->seq = garmin_data_p->seq_counter++;
322 		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
323 		state = garmin_data_p->state;
324 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
325 
326 		/* in serial mode, if someone is waiting for data from
327 		   the device, iconvert and send the next packet to tty. */
328 		if (result && (state == STATE_GSP_WAIT_DATA)) {
329 			gsp_next_packet(garmin_data_p);
330 		}
331 	}
332 	return result;
333 }
334 
335 
336 /* get the next pending packet */
337 static struct garmin_packet *pkt_pop(struct garmin_data * garmin_data_p)
338 {
339 	unsigned long flags;
340 	struct garmin_packet *result = NULL;
341 
342 	spin_lock_irqsave(&garmin_data_p->lock, flags);
343 	if (!list_empty(&garmin_data_p->pktlist)) {
344 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
345 		list_del(&result->list);
346 	}
347 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
348 	return result;
349 }
350 
351 
352 /* free up all queued data */
353 static void pkt_clear(struct garmin_data * garmin_data_p)
354 {
355 	unsigned long flags;
356 	struct garmin_packet *result = NULL;
357 
358 	dbg("%s", __FUNCTION__);
359 
360 	spin_lock_irqsave(&garmin_data_p->lock, flags);
361 	while (!list_empty(&garmin_data_p->pktlist)) {
362 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
363 		list_del(&result->list);
364 		kfree(result);
365 	}
366 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
367 }
368 
369 
370 /******************************************************************************
371  * garmin serial protocol handling handling
372  ******************************************************************************/
373 
374 /* send an ack packet back to the tty */
375 static int gsp_send_ack(struct garmin_data * garmin_data_p, __u8 pkt_id)
376 {
377 	__u8 pkt[10];
378 	__u8 cksum = 0;
379 	__u8 *ptr = pkt;
380 	unsigned  l = 0;
381 
382 	dbg("%s - pkt-id: 0x%X.", __FUNCTION__, 0xFF & pkt_id);
383 
384 	*ptr++ = DLE;
385 	*ptr++ = ACK;
386 	cksum += ACK;
387 
388 	*ptr++ = 2;
389 	cksum += 2;
390 
391 	*ptr++ = pkt_id;
392 	cksum += pkt_id;
393 
394 	if (pkt_id == DLE) {
395 		*ptr++ = DLE;
396 	}
397 
398 	*ptr++ = 0;
399 	*ptr++ = 0xFF & (-cksum);
400 	*ptr++ = DLE;
401 	*ptr++ = ETX;
402 
403 	l = ptr-pkt;
404 
405 	send_to_tty(garmin_data_p->port, pkt, l);
406 	return 0;
407 }
408 
409 
410 
411 /*
412  * called for a complete packet received from tty layer
413  *
414  * the complete packet (pkzid ... cksum) is in garmin_data_p->inbuf starting
415  * at GSP_INITIAL_OFFSET.
416  *
417  * count - number of bytes in the input buffer including space reserved for
418  *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet
419  *         (including pkt-id, data-length a. cksum)
420  */
421 static int gsp_rec_packet(struct garmin_data * garmin_data_p, int count)
422 {
423 	const __u8* recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
424 	__le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;
425 
426 	int cksum = 0;
427 	int n = 0;
428 	int pktid = recpkt[0];
429 	int size = recpkt[1];
430 
431 	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
432 			       __FUNCTION__, count-GSP_INITIAL_OFFSET, recpkt);
433 
434 	if (size != (count-GSP_INITIAL_OFFSET-3)) {
435 		dbg("%s - invalid size, expected %d bytes, got %d",
436 			__FUNCTION__, size, (count-GSP_INITIAL_OFFSET-3));
437 		return -EINVPKT;
438 	}
439 
440 	cksum += *recpkt++;
441 	cksum += *recpkt++;
442 
443 	// sanity check, remove after test ...
444 	if ((__u8*)&(usbdata[3]) != recpkt) {
445 		dbg("%s - ptr mismatch %p - %p",
446 			__FUNCTION__, &(usbdata[4]), recpkt);
447 		return -EINVPKT;
448 	}
449 
450 	while (n < size) {
451 		cksum += *recpkt++;
452 		n++;
453 	}
454 
455 	if ((0xff & (cksum + *recpkt)) != 0) {
456 		dbg("%s - invalid checksum, expected %02x, got %02x",
457 			__FUNCTION__, 0xff & -cksum, 0xff & *recpkt);
458 		return -EINVPKT;
459 	}
460 
461 	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
462 	usbdata[1] = __cpu_to_le32(pktid);
463 	usbdata[2] = __cpu_to_le32(size);
464 
465 	garmin_write_bulk (garmin_data_p->port, garmin_data_p->inbuffer,
466 			   GARMIN_PKTHDR_LENGTH+size);
467 
468 	/* if this was an abort-transfer command, flush all
469 	   queued data. */
470 	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
471 		garmin_data_p->flags |= FLAGS_DROP_DATA;
472 		pkt_clear(garmin_data_p);
473 	}
474 
475 	return count;
476 }
477 
478 
479 
480 /*
481  * Called for data received from tty
482  *
483  * buf contains the data read, it may span more than one packet or even
484  * incomplete packets
485  *
486  * input record should be a serial-record, but it may not be complete.
487  * Copy it into our local buffer, until an etx is seen (or an error
488  * occurs).
489  * Once the record is complete, convert into a usb packet and send it
490  * to the bulk pipe, send an ack back to the tty.
491  *
492  * If the input is an ack, just send the last queued packet to the
493  * tty layer.
494  *
495  * if the input is an abort command, drop all queued data.
496  */
497 
498 static int gsp_receive(struct garmin_data * garmin_data_p,
499 		       const unsigned char *buf, int count)
500 {
501 	unsigned long flags;
502 	int offs = 0;
503 	int ack_or_nak_seen = 0;
504 	int i = 0;
505 	__u8 *dest;
506 	int size;
507 	// dleSeen: set if last byte read was a DLE
508 	int dleSeen;
509 	// skip: if set, skip incoming data until possible start of
510 	//       new packet
511 	int skip;
512 	__u8 data;
513 
514 	spin_lock_irqsave(&garmin_data_p->lock, flags);
515 	dest = garmin_data_p->inbuffer;
516 	size = garmin_data_p->insize;
517 	dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
518 	skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
519 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
520 
521 	dbg("%s - dle=%d skip=%d size=%d count=%d",
522 		__FUNCTION__, dleSeen, skip, size, count);
523 
524 	if (size == 0) {
525 		size = GSP_INITIAL_OFFSET;
526 	}
527 
528 	while (offs < count) {
529 
530 		data = *(buf+offs);
531 		offs ++;
532 
533 		if (data == DLE) {
534 			if (skip) { /* start of a new pkt */
535 				skip = 0;
536 				size = GSP_INITIAL_OFFSET;
537 				dleSeen = 1;
538 			} else if (dleSeen) {
539 				dest[size++] = data;
540 				dleSeen = 0;
541 			} else {
542 				dleSeen = 1;
543 			}
544 		} else if (data == ETX) {
545 			if (dleSeen) {
546 				/* packet complete */
547 
548 				data = dest[GSP_INITIAL_OFFSET];
549 
550 				if (data == ACK) {
551 					ack_or_nak_seen = ACK;
552 					dbg("ACK packet complete.");
553 				} else if (data == NAK) {
554 					ack_or_nak_seen = NAK;
555 					dbg("NAK packet complete.");
556 				} else {
557 					dbg("packet complete "
558 						        "- id=0x%X.",
559 						        0xFF & data);
560 					gsp_rec_packet(garmin_data_p, size);
561 				}
562 
563 				skip = 1;
564 				size = GSP_INITIAL_OFFSET;
565 				dleSeen = 0;
566 			} else {
567 				dest[size++] = data;
568 			}
569 		} else if (!skip) {
570 
571 			if (dleSeen) {
572 				dbg("non-masked DLE at %d - restarting", i);
573 				size = GSP_INITIAL_OFFSET;
574 				dleSeen = 0;
575 			}
576 
577 			dest[size++] = data;
578 		}
579 
580 		if (size >= GPS_IN_BUFSIZ) {
581 			dbg("%s - packet too large.", __FUNCTION__);
582 			skip = 1;
583 			size = GSP_INITIAL_OFFSET;
584 			dleSeen = 0;
585 		}
586 	}
587 
588 	spin_lock_irqsave(&garmin_data_p->lock, flags);
589 
590 	garmin_data_p->insize = size;
591 
592 	// copy flags back to structure
593 	if (skip)
594 		garmin_data_p->flags |= FLAGS_GSP_SKIP;
595 	else
596 		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;
597 
598 	if (dleSeen)
599 		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
600 	else
601 		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;
602 
603 	if (ack_or_nak_seen) {
604 		garmin_data_p->state = STATE_GSP_WAIT_DATA;
605 	}
606 
607 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
608 
609 	if (ack_or_nak_seen) {
610 		gsp_next_packet(garmin_data_p);
611 	}
612 
613 	return count;
614 }
615 
616 
617 
618 
619 /*
620  * Sends a usb packet to the tty
621  *
622  * Assumes, that all packages and at an usb-packet boundary.
623  *
624  * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
625  */
626 static int gsp_send(struct garmin_data * garmin_data_p,
627 		    const unsigned char *buf, int count)
628 {
629 	const unsigned char *src;
630 	unsigned char *dst;
631 	int pktid = 0;
632 	int datalen = 0;
633 	int cksum = 0;
634 	int i=0;
635 	int k;
636 
637 	dbg("%s - state %d - %d bytes.", __FUNCTION__,
638 	         garmin_data_p->state, count);
639 
640 	k = garmin_data_p->outsize;
641 	if ((k+count) > GPS_OUT_BUFSIZ) {
642 		dbg("packet too large");
643 		garmin_data_p->outsize = 0;
644 		return -4;
645 	}
646 
647 	memcpy(garmin_data_p->outbuffer+k, buf, count);
648 	k += count;
649 	garmin_data_p->outsize = k;
650 
651 	if (k >= GARMIN_PKTHDR_LENGTH) {
652 		pktid  = getPacketId(garmin_data_p->outbuffer);
653 		datalen= getDataLength(garmin_data_p->outbuffer);
654 		i = GARMIN_PKTHDR_LENGTH + datalen;
655 		if (k < i)
656 			return 0;
657 	} else {
658 		return 0;
659 	}
660 
661 	dbg("%s - %d bytes in buffer, %d bytes in pkt.", __FUNCTION__,
662 	         k, i);
663 
664 	/* garmin_data_p->outbuffer now contains a complete packet */
665 
666 	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
667 		                   __FUNCTION__, k, garmin_data_p->outbuffer);
668 
669 	garmin_data_p->outsize = 0;
670 
671 	if (GARMIN_LAYERID_APPL != getLayerId(garmin_data_p->outbuffer)) {
672 		dbg("not an application packet (%d)",
673 		        getLayerId(garmin_data_p->outbuffer));
674 		return -1;
675 	}
676 
677 	if (pktid > 255) {
678 		dbg("packet-id %d too large", pktid);
679 		return -2;
680 	}
681 
682 	if (datalen > 255) {
683 		dbg("packet-size %d too large", datalen);
684 		return -3;
685 	}
686 
687 	/* the serial protocol should be able to handle this packet */
688 
689 	k = 0;
690 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
691 	for (i=0; i<datalen; i++) {
692 		if (*src++ == DLE)
693 			k++;
694 	}
695 
696 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
697 	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
698 		/* can't add stuffing DLEs in place, move data to end
699 		   of buffer ... */
700 		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
701 		memcpy(dst, src, datalen);
702 		src = dst;
703 	}
704 
705 	dst = garmin_data_p->outbuffer;
706 
707 	*dst++ = DLE;
708 	*dst++ = pktid;
709 	cksum += pktid;
710 	*dst++ = datalen;
711 	cksum += datalen;
712 	if (datalen == DLE)
713 		*dst++ = DLE;
714 
715 	for (i=0; i<datalen; i++) {
716 		__u8 c = *src++;
717 		*dst++ = c;
718 		cksum += c;
719 		if (c == DLE)
720 			*dst++ = DLE;
721 	}
722 
723 	cksum = 0xFF & -cksum;
724 	*dst++ = cksum;
725 	if (cksum == DLE)
726 		*dst++ = DLE;
727 	*dst++ = DLE;
728 	*dst++ = ETX;
729 
730 	i = dst-garmin_data_p->outbuffer;
731 
732 	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);
733 
734 	garmin_data_p->pkt_id = pktid;
735 	garmin_data_p->state  = STATE_WAIT_TTY_ACK;
736 
737 	return i;
738 }
739 
740 
741 
742 
743 
744 /*
745  * Process the next pending data packet - if there is one
746  */
747 static void gsp_next_packet(struct garmin_data * garmin_data_p)
748 {
749 	struct garmin_packet *pkt = NULL;
750 
751 	while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
752 		dbg("%s - next pkt: %d", __FUNCTION__, pkt->seq);
753 		if (gsp_send(garmin_data_p, pkt->data, pkt->size) > 0) {
754 			kfree(pkt);
755 			return;
756 		}
757 		kfree(pkt);
758 	}
759 }
760 
761 
762 
763 
764 /******************************************************************************
765  * garmin native mode
766  ******************************************************************************/
767 
768 
769 /*
770  * Called for data received from tty
771  *
772  * The input data is expected to be in garmin usb-packet format.
773  *
774  * buf contains the data read, it may span more than one packet
775  * or even incomplete packets
776  */
777 static int nat_receive(struct garmin_data * garmin_data_p,
778 		       const unsigned char *buf, int count)
779 {
780 	unsigned long flags;
781 	__u8 * dest;
782 	int offs = 0;
783 	int result = count;
784 	int len;
785 
786 	while (offs < count) {
787 		// if buffer contains header, copy rest of data
788 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
789 			len = GARMIN_PKTHDR_LENGTH
790 			      +getDataLength(garmin_data_p->inbuffer);
791 		else
792 			len = GARMIN_PKTHDR_LENGTH;
793 
794 		if (len >= GPS_IN_BUFSIZ) {
795 			/* seem to be an invalid packet, ignore rest of input */
796 			dbg("%s - packet size too large: %d",
797 			        __FUNCTION__, len);
798 			garmin_data_p->insize = 0;
799 			count = 0;
800 			result = -EINVPKT;
801 		} else {
802 			len -= garmin_data_p->insize;
803 			if (len > (count-offs))
804 				len = (count-offs);
805 			if (len > 0) {
806 				dest = garmin_data_p->inbuffer
807 				       	+garmin_data_p->insize;
808 				memcpy(dest, buf+offs, len);
809 				garmin_data_p->insize += len;
810 				offs += len;
811 			}
812 		}
813 
814 		/* do we have a complete packet ? */
815 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
816 			len = GARMIN_PKTHDR_LENGTH+
817 			   getDataLength(garmin_data_p->inbuffer);
818 			if (garmin_data_p->insize >= len) {
819 				garmin_write_bulk (garmin_data_p->port,
820 				                   garmin_data_p->inbuffer,
821 				                   len);
822 				garmin_data_p->insize = 0;
823 
824 				/* if this was an abort-transfer command,
825 				   flush all queued data. */
826 				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
827 					spin_lock_irqsave(&garmin_data_p->lock, flags);
828 					garmin_data_p->flags |= FLAGS_DROP_DATA;
829 					spin_unlock_irqrestore(&garmin_data_p->lock, flags);
830 					pkt_clear(garmin_data_p);
831 				}
832 			}
833 		}
834 	}
835 	return result;
836 }
837 
838 
839 /******************************************************************************
840  * private packets
841  ******************************************************************************/
842 
843 static void priv_status_resp(struct usb_serial_port *port)
844 {
845 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
846 	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;
847 
848 	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
849 	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
850 	pkt[2] = __cpu_to_le32(12);
851 	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
852 	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
853 	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);
854 
855 	send_to_tty(port, (__u8*)pkt, 6*4);
856 }
857 
858 
859 /******************************************************************************
860  * Garmin specific driver functions
861  ******************************************************************************/
862 
863 static int process_resetdev_request(struct usb_serial_port *port)
864 {
865 	unsigned long flags;
866 	int status;
867 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
868 
869 	spin_lock_irqsave(&garmin_data_p->lock, flags);
870 	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
871 	garmin_data_p->state = STATE_RESET;
872 	garmin_data_p->serial_num = 0;
873 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
874 
875 	usb_kill_urb (port->interrupt_in_urb);
876 	dbg("%s - usb_reset_device", __FUNCTION__ );
877 	status = usb_reset_device(port->serial->dev);
878 	if (status)
879 		dbg("%s - usb_reset_device failed: %d",
880 			__FUNCTION__, status);
881 	return status;
882 }
883 
884 
885 
886 /*
887  * clear all cached data
888  */
889 static int garmin_clear(struct garmin_data * garmin_data_p)
890 {
891 	unsigned long flags;
892 	int status = 0;
893 
894 	struct usb_serial_port *port = garmin_data_p->port;
895 
896 	if (port != NULL && garmin_data_p->flags & FLAGS_APP_RESP_SEEN) {
897 		/* send a terminate command */
898 		status = garmin_write_bulk(port, GARMIN_STOP_TRANSFER_REQ,
899 		                           sizeof(GARMIN_STOP_TRANSFER_REQ));
900 	}
901 
902 	/* flush all queued data */
903 	pkt_clear(garmin_data_p);
904 
905 	spin_lock_irqsave(&garmin_data_p->lock, flags);
906 	garmin_data_p->insize = 0;
907 	garmin_data_p->outsize = 0;
908 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
909 
910 	return status;
911 }
912 
913 
914 
915 
916 
917 
918 static int garmin_init_session(struct usb_serial_port *port)
919 {
920 	unsigned long flags;
921 	struct usb_serial *serial = port->serial;
922 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
923 	int status = 0;
924 
925 	if (status == 0) {
926 		usb_kill_urb (port->interrupt_in_urb);
927 
928 		dbg("%s - adding interrupt input", __FUNCTION__);
929 		port->interrupt_in_urb->dev = serial->dev;
930 		status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
931 		if (status)
932 			dev_err(&serial->dev->dev,
933 			        "%s - failed submitting interrupt urb,"
934 				" error %d\n",
935 			        __FUNCTION__, status);
936 	}
937 
938 	if (status == 0) {
939 		dbg("%s - starting session ...", __FUNCTION__);
940 		garmin_data_p->state = STATE_ACTIVE;
941 		status = garmin_write_bulk(port, GARMIN_START_SESSION_REQ,
942 		                           sizeof(GARMIN_START_SESSION_REQ));
943 
944 		if (status >= 0) {
945 
946 			spin_lock_irqsave(&garmin_data_p->lock, flags);
947 			garmin_data_p->ignorePkts++;
948 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
949 
950 			/* not needed, but the win32 driver does it too ... */
951 			status = garmin_write_bulk(port,
952 						   GARMIN_START_SESSION_REQ2,
953 			                           sizeof(GARMIN_START_SESSION_REQ2));
954 			if (status >= 0) {
955 				status = 0;
956 				spin_lock_irqsave(&garmin_data_p->lock, flags);
957 				garmin_data_p->ignorePkts++;
958 				spin_unlock_irqrestore(&garmin_data_p->lock, flags);
959 			}
960 		}
961 	}
962 
963 	return status;
964 }
965 
966 
967 
968 
969 
970 static int garmin_open (struct usb_serial_port *port, struct file *filp)
971 {
972 	unsigned long flags;
973 	int status = 0;
974 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
975 
976 	dbg("%s - port %d", __FUNCTION__, port->number);
977 
978 	/*
979 	 * Force low_latency on so that our tty_push actually forces the data
980 	 * through, otherwise it is scheduled, and with high data rates (like
981 	 * with OHCI) data can get lost.
982 	 */
983 	if (port->tty)
984 		port->tty->low_latency = 1;
985 
986 	spin_lock_irqsave(&garmin_data_p->lock, flags);
987 	garmin_data_p->mode  = initial_mode;
988 	garmin_data_p->count = 0;
989 	garmin_data_p->flags = 0;
990 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
991 
992 	/* shutdown any bulk reads that might be going on */
993 	usb_kill_urb (port->write_urb);
994 	usb_kill_urb (port->read_urb);
995 
996 	if (garmin_data_p->state == STATE_RESET) {
997 		status = garmin_init_session(port);
998 	}
999 
1000 	garmin_data_p->state = STATE_ACTIVE;
1001 
1002 	return status;
1003 }
1004 
1005 
1006 static void garmin_close (struct usb_serial_port *port, struct file * filp)
1007 {
1008 	struct usb_serial *serial = port->serial;
1009 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1010 
1011 	dbg("%s - port %d - mode=%d state=%d flags=0x%X", __FUNCTION__,
1012 		port->number, garmin_data_p->mode,
1013 		garmin_data_p->state, garmin_data_p->flags);
1014 
1015 	if (!serial)
1016 		return;
1017 
1018 	garmin_clear(garmin_data_p);
1019 
1020 	/* shutdown our urbs */
1021 	usb_kill_urb (port->read_urb);
1022 	usb_kill_urb (port->write_urb);
1023 
1024 	if (noResponseFromAppLayer(garmin_data_p) ||
1025 	    ((garmin_data_p->flags & CLEAR_HALT_REQUIRED) != 0)) {
1026 		process_resetdev_request(port);
1027 		garmin_data_p->state = STATE_RESET;
1028 	} else {
1029 		garmin_data_p->state = STATE_DISCONNECTED;
1030 	}
1031 }
1032 
1033 
1034 static void garmin_write_bulk_callback (struct urb *urb)
1035 {
1036 	unsigned long flags;
1037 	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
1038 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1039 
1040 	/* free up the transfer buffer, as usb_free_urb() does not do this */
1041 	kfree (urb->transfer_buffer);
1042 
1043 	dbg("%s - port %d", __FUNCTION__, port->number);
1044 
1045 	if (urb->status) {
1046 		dbg("%s - nonzero write bulk status received: %d",
1047 			__FUNCTION__, urb->status);
1048 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1049 		garmin_data_p->flags |= CLEAR_HALT_REQUIRED;
1050 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1051 	}
1052 
1053 	usb_serial_port_softint(port);
1054 }
1055 
1056 
1057 static int garmin_write_bulk (struct usb_serial_port *port,
1058 			      const unsigned char *buf, int count)
1059 {
1060 	unsigned long flags;
1061 	struct usb_serial *serial = port->serial;
1062 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1063 	struct urb *urb;
1064 	unsigned char *buffer;
1065 	int status;
1066 
1067 	dbg("%s - port %d, state %d", __FUNCTION__, port->number,
1068 		garmin_data_p->state);
1069 
1070 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1071 	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
1072 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1073 
1074 	buffer = kmalloc (count, GFP_ATOMIC);
1075 	if (!buffer) {
1076 		dev_err(&port->dev, "out of memory\n");
1077 		return -ENOMEM;
1078 	}
1079 
1080 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1081 	if (!urb) {
1082 		dev_err(&port->dev, "no more free urbs\n");
1083 		kfree (buffer);
1084 		return -ENOMEM;
1085 	}
1086 
1087 	memcpy (buffer, buf, count);
1088 
1089 	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, buffer);
1090 
1091 	usb_fill_bulk_urb (urb, serial->dev,
1092 			 	usb_sndbulkpipe (serial->dev,
1093 				port->bulk_out_endpointAddress),
1094 				buffer, count,
1095 				garmin_write_bulk_callback, port);
1096 	urb->transfer_flags |= URB_ZERO_PACKET;
1097 
1098 	if (GARMIN_LAYERID_APPL == getLayerId(buffer)) {
1099 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1100 		garmin_data_p->flags |= FLAGS_APP_REQ_SEEN;
1101 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1102 		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
1103 			pkt_clear(garmin_data_p);
1104 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
1105 		}
1106 	}
1107 
1108 	/* send it down the pipe */
1109 	status = usb_submit_urb(urb, GFP_ATOMIC);
1110 	if (status) {
1111 		dev_err(&port->dev,
1112 		        "%s - usb_submit_urb(write bulk) "
1113 		        "failed with status = %d\n",
1114 				__FUNCTION__, status);
1115 		count = status;
1116 	} else {
1117 
1118 		if (GARMIN_LAYERID_APPL == getLayerId(buffer)
1119 		    && (garmin_data_p->mode == MODE_GARMIN_SERIAL))  {
1120 
1121 			gsp_send_ack(garmin_data_p, buffer[4]);
1122 		}
1123 	}
1124 
1125 	/* we are done with this urb, so let the host driver
1126 	 * really free it when it is finished with it */
1127 	usb_free_urb (urb);
1128 
1129 	return count;
1130 }
1131 
1132 
1133 
1134 static int garmin_write (struct usb_serial_port *port,
1135 			 const unsigned char *buf, int count)
1136 {
1137 	unsigned long flags;
1138 	int pktid, pktsiz, len;
1139 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1140 	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;
1141 
1142 	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, buf);
1143 
1144 	/* check for our private packets */
1145 	if (count >= GARMIN_PKTHDR_LENGTH) {
1146 
1147 		len = PRIVPKTSIZ;
1148 		if (count < len)
1149 			len = count;
1150 
1151 		memcpy(garmin_data_p->privpkt, buf, len);
1152 
1153 		pktsiz = getDataLength(garmin_data_p->privpkt);
1154 		pktid  = getPacketId(garmin_data_p->privpkt);
1155 
1156 		if (count == (GARMIN_PKTHDR_LENGTH+pktsiz)
1157 		    && GARMIN_LAYERID_PRIVATE == getLayerId(garmin_data_p->privpkt)) {
1158 
1159 			dbg("%s - processing private request %d",
1160 				__FUNCTION__, pktid);
1161 
1162 			// drop all unfinished transfers
1163 			garmin_clear(garmin_data_p);
1164 
1165 			switch(pktid) {
1166 
1167 			case PRIV_PKTID_SET_DEBUG:
1168 				if (pktsiz != 4)
1169 					return -EINVPKT;
1170 				debug = __le32_to_cpu(privpkt[3]);
1171 				dbg("%s - debug level set to 0x%X",
1172 					__FUNCTION__, debug);
1173 				break;
1174 
1175 			case PRIV_PKTID_SET_MODE:
1176 				if (pktsiz != 4)
1177 					return -EINVPKT;
1178 				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
1179 				dbg("%s - mode set to %d",
1180 					__FUNCTION__, garmin_data_p->mode);
1181 				break;
1182 
1183 			case PRIV_PKTID_INFO_REQ:
1184 				priv_status_resp(port);
1185 				break;
1186 
1187 			case PRIV_PKTID_RESET_REQ:
1188 				spin_lock_irqsave(&garmin_data_p->lock, flags);
1189 				garmin_data_p->flags |= FLAGS_APP_REQ_SEEN;
1190 				spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1191 				break;
1192 
1193 			case PRIV_PKTID_SET_DEF_MODE:
1194 				if (pktsiz != 4)
1195 					return -EINVPKT;
1196 				initial_mode = __le32_to_cpu(privpkt[3]);
1197 				dbg("%s - initial_mode set to %d",
1198 					__FUNCTION__,
1199 					garmin_data_p->mode);
1200 				break;
1201 			}
1202 			return count;
1203 		}
1204 	}
1205 
1206 	garmin_data_p->ignorePkts = 0;
1207 
1208 	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1209 		return gsp_receive(garmin_data_p, buf, count);
1210 	} else {	/* MODE_NATIVE */
1211 		return nat_receive(garmin_data_p, buf, count);
1212 	}
1213 }
1214 
1215 
1216 static int garmin_write_room (struct usb_serial_port *port)
1217 {
1218 	/*
1219 	 * Report back the bytes currently available in the output buffer.
1220 	 */
1221 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1222 	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
1223 }
1224 
1225 
1226 static int garmin_chars_in_buffer (struct usb_serial_port *port)
1227 {
1228 	/*
1229 	 * Report back the number of bytes currently in our input buffer.
1230 	 * Will this lock up the driver - the buffer contains an incomplete
1231 	 * package which will not be written to the device until it
1232 	 * has been completed ?
1233 	 */
1234 	//struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1235 	//return garmin_data_p->insize;
1236 	return 0;
1237 }
1238 
1239 
1240 static void garmin_read_process(struct garmin_data * garmin_data_p,
1241 				 unsigned char *data, unsigned data_length)
1242 {
1243 	unsigned long flags;
1244 
1245 	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
1246 		/* abort-transfer cmd is actice */
1247 		dbg("%s - pkt dropped", __FUNCTION__);
1248 	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
1249 	           garmin_data_p->state != STATE_RESET ) {
1250 
1251 		/* remember any appl.layer packets, so we know
1252 		   if a reset is required or not when closing
1253 		   the device */
1254 		if (0 == memcmp(data, GARMIN_APP_LAYER_REPLY,
1255 		                sizeof(GARMIN_APP_LAYER_REPLY))) {
1256 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1257 			garmin_data_p->flags |= FLAGS_APP_RESP_SEEN;
1258 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1259 		}
1260 
1261 		/* if throttling is active or postprecessing is required
1262 		   put the received data in the input queue, otherwise
1263 		   send it directly to the tty port */
1264 		if (garmin_data_p->flags & FLAGS_QUEUING) {
1265 			pkt_add(garmin_data_p, data, data_length);
1266 		} else if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1267 			if (getLayerId(data) == GARMIN_LAYERID_APPL) {
1268 				pkt_add(garmin_data_p, data, data_length);
1269 			}
1270 		} else {
1271 			send_to_tty(garmin_data_p->port, data, data_length);
1272 		}
1273 	}
1274 }
1275 
1276 
1277 static void garmin_read_bulk_callback (struct urb *urb)
1278 {
1279 	unsigned long flags;
1280 	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
1281 	struct usb_serial *serial =  port->serial;
1282 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1283 	unsigned char *data = urb->transfer_buffer;
1284 	int status;
1285 
1286 	dbg("%s - port %d", __FUNCTION__, port->number);
1287 
1288 	if (!serial) {
1289 		dbg("%s - bad serial pointer, exiting", __FUNCTION__);
1290 		return;
1291 	}
1292 
1293 	if (urb->status) {
1294 		dbg("%s - nonzero read bulk status received: %d",
1295 			__FUNCTION__, urb->status);
1296 		return;
1297 	}
1298 
1299 	usb_serial_debug_data(debug, &port->dev,
1300 				__FUNCTION__, urb->actual_length, data);
1301 
1302 	garmin_read_process(garmin_data_p, data, urb->actual_length);
1303 
1304 	if (urb->actual_length == 0 &&
1305 			0 != (garmin_data_p->flags & FLAGS_BULK_IN_RESTART)) {
1306 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1307 		garmin_data_p->flags &= ~FLAGS_BULK_IN_RESTART;
1308 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1309 		status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1310 		if (status)
1311 			dev_err(&port->dev,
1312 				"%s - failed resubmitting read urb, error %d\n",
1313 			        __FUNCTION__, status);
1314 	} else if (urb->actual_length > 0) {
1315 		/* Continue trying to read until nothing more is received  */
1316 		if (0 == (garmin_data_p->flags & FLAGS_THROTTLED)) {
1317 			status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1318 			if (status)
1319 				dev_err(&port->dev,
1320 					"%s - failed resubmitting read urb, error %d\n",
1321 			        	__FUNCTION__, status);
1322 		}
1323 	} else {
1324 		dbg("%s - end of bulk data", __FUNCTION__);
1325 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1326 		garmin_data_p->flags &= ~FLAGS_BULK_IN_ACTIVE;
1327 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1328 	}
1329 	return;
1330 }
1331 
1332 
1333 static void garmin_read_int_callback (struct urb *urb)
1334 {
1335 	unsigned long flags;
1336 	int status;
1337 	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
1338 	struct usb_serial *serial = port->serial;
1339 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1340 	unsigned char *data = urb->transfer_buffer;
1341 
1342 	switch (urb->status) {
1343 	case 0:
1344 		/* success */
1345 		break;
1346 	case -ECONNRESET:
1347 	case -ENOENT:
1348 	case -ESHUTDOWN:
1349 		/* this urb is terminated, clean up */
1350 		dbg("%s - urb shutting down with status: %d",
1351 			__FUNCTION__, urb->status);
1352 		return;
1353 	default:
1354 		dbg("%s - nonzero urb status received: %d",
1355 			__FUNCTION__, urb->status);
1356 		return;
1357 	}
1358 
1359 	usb_serial_debug_data(debug, &port->dev, __FUNCTION__,
1360 				urb->actual_length, urb->transfer_buffer);
1361 
1362 	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
1363 	    0 == memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
1364 		        sizeof(GARMIN_BULK_IN_AVAIL_REPLY))) {
1365 
1366 		dbg("%s - bulk data available.", __FUNCTION__);
1367 
1368 		if (0 == (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1369 
1370 			/* bulk data available */
1371 			usb_fill_bulk_urb (port->read_urb, serial->dev,
1372 					usb_rcvbulkpipe (serial->dev,
1373 					port->bulk_in_endpointAddress),
1374 					port->read_urb->transfer_buffer,
1375 					port->read_urb->transfer_buffer_length,
1376 					garmin_read_bulk_callback, port);
1377 			status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1378 			if (status) {
1379 				dev_err(&port->dev,
1380 					"%s - failed submitting read urb, error %d\n",
1381 				__FUNCTION__, status);
1382 			} else {
1383 				spin_lock_irqsave(&garmin_data_p->lock, flags);
1384 				garmin_data_p->flags |= FLAGS_BULK_IN_ACTIVE;
1385 				/* do not send this packet to the user */
1386 				garmin_data_p->ignorePkts = 1;
1387 				spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1388 			}
1389 		} else {
1390 			/* bulk-in transfer still active */
1391 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1392 			garmin_data_p->flags |= FLAGS_BULK_IN_RESTART;
1393 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1394 		}
1395 
1396 	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
1397 			 && 0 == memcmp(data, GARMIN_START_SESSION_REPLY,
1398 			                sizeof(GARMIN_START_SESSION_REPLY))) {
1399 
1400 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1401 		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
1402 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1403 
1404 		/* save the serial number */
1405 		garmin_data_p->serial_num
1406 			= __le32_to_cpup((__le32*)(data+GARMIN_PKTHDR_LENGTH));
1407 
1408 		dbg("%s - start-of-session reply seen - serial %u.",
1409 			__FUNCTION__, garmin_data_p->serial_num);
1410 	}
1411 
1412 	if (garmin_data_p->ignorePkts) {
1413 		/* this reply belongs to a request generated by the driver,
1414 		   ignore it. */
1415 		dbg("%s - pkt ignored (%d)",
1416 			__FUNCTION__, garmin_data_p->ignorePkts);
1417 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1418 		garmin_data_p->ignorePkts--;
1419 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1420 	} else {
1421 		garmin_read_process(garmin_data_p, data, urb->actual_length);
1422 	}
1423 
1424 	port->interrupt_in_urb->dev = port->serial->dev;
1425 	status = usb_submit_urb (urb, GFP_ATOMIC);
1426 	if (status)
1427 		dev_err(&urb->dev->dev,
1428 			"%s - Error %d submitting interrupt urb\n",
1429 			__FUNCTION__, status);
1430 }
1431 
1432 
1433 /*
1434  * Sends the next queued packt to the tty port (garmin native mode only)
1435  * and then sets a timer to call itself again until all queued data
1436  * is sent.
1437  */
1438 static int garmin_flush_queue(struct garmin_data * garmin_data_p)
1439 {
1440 	unsigned long flags;
1441 	struct garmin_packet *pkt;
1442 
1443 	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1444 		pkt = pkt_pop(garmin_data_p);
1445 		if (pkt != NULL) {
1446 			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
1447 			kfree(pkt);
1448 			mod_timer(&garmin_data_p->timer, (1)+jiffies);
1449 
1450 		} else {
1451 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1452 			garmin_data_p->flags &= ~FLAGS_QUEUING;
1453 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1454 		}
1455 	}
1456 	return 0;
1457 }
1458 
1459 
1460 static void garmin_throttle (struct usb_serial_port *port)
1461 {
1462 	unsigned long flags;
1463 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1464 
1465 	dbg("%s - port %d", __FUNCTION__, port->number);
1466 	/* set flag, data received will be put into a queue
1467 	   for later processing */
1468 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1469 	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
1470 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1471 }
1472 
1473 
1474 static void garmin_unthrottle (struct usb_serial_port *port)
1475 {
1476 	unsigned long flags;
1477 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1478 	int status;
1479 
1480 	dbg("%s - port %d", __FUNCTION__, port->number);
1481 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1482 	garmin_data_p->flags &= ~FLAGS_THROTTLED;
1483 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1484 
1485 	/* in native mode send queued data to tty, in
1486 	   serial mode nothing needs to be done here */
1487 	if (garmin_data_p->mode == MODE_NATIVE)
1488 		garmin_flush_queue(garmin_data_p);
1489 
1490 	if (0 != (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1491 		status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1492 		if (status)
1493 			dev_err(&port->dev,
1494 				"%s - failed resubmitting read urb, error %d\n",
1495 				__FUNCTION__, status);
1496 	}
1497 }
1498 
1499 
1500 
1501 /*
1502  * The timer is currently only used to send queued packets to
1503  * the tty in cases where the protocol provides no own handshaking
1504  * to initiate the transfer.
1505  */
1506 static void timeout_handler(unsigned long data)
1507 {
1508 	struct garmin_data *garmin_data_p = (struct garmin_data *) data;
1509 
1510 	/* send the next queued packet to the tty port */
1511 	if (garmin_data_p->mode == MODE_NATIVE)
1512 		if (garmin_data_p->flags & FLAGS_QUEUING)
1513 			garmin_flush_queue(garmin_data_p);
1514 }
1515 
1516 
1517 
1518 static int garmin_attach (struct usb_serial *serial)
1519 {
1520 	int status = 0;
1521 	struct usb_serial_port *port = serial->port[0];
1522 	struct garmin_data * garmin_data_p = NULL;
1523 
1524 	dbg("%s", __FUNCTION__);
1525 
1526 	garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
1527 	if (garmin_data_p == NULL) {
1528 		dev_err(&port->dev, "%s - Out of memory\n", __FUNCTION__);
1529 		return -ENOMEM;
1530 	}
1531 	init_timer(&garmin_data_p->timer);
1532 	spin_lock_init(&garmin_data_p->lock);
1533 	INIT_LIST_HEAD(&garmin_data_p->pktlist);
1534 	//garmin_data_p->timer.expires = jiffies + session_timeout;
1535 	garmin_data_p->timer.data = (unsigned long)garmin_data_p;
1536 	garmin_data_p->timer.function = timeout_handler;
1537 	garmin_data_p->port = port;
1538 	garmin_data_p->state = 0;
1539 	garmin_data_p->count = 0;
1540 	usb_set_serial_port_data(port, garmin_data_p);
1541 
1542 	status = garmin_init_session(port);
1543 
1544 	return status;
1545 }
1546 
1547 
1548 static void garmin_shutdown (struct usb_serial *serial)
1549 {
1550 	struct usb_serial_port *port = serial->port[0];
1551 	struct garmin_data * garmin_data_p = usb_get_serial_port_data(port);
1552 
1553 	dbg("%s", __FUNCTION__);
1554 
1555 	usb_kill_urb (port->interrupt_in_urb);
1556 	del_timer_sync(&garmin_data_p->timer);
1557 	kfree (garmin_data_p);
1558 	usb_set_serial_port_data(port, NULL);
1559 }
1560 
1561 
1562 /* All of the device info needed */
1563 static struct usb_serial_driver garmin_device = {
1564 	.driver = {
1565 		.owner       = THIS_MODULE,
1566 		.name        = "garmin_gps",
1567 	},
1568 	.description         = "Garmin GPS usb/tty",
1569 	.id_table            = id_table,
1570 	.num_interrupt_in    = 1,
1571 	.num_bulk_in         = 1,
1572 	.num_bulk_out        = 1,
1573 	.num_ports           = 1,
1574 	.open                = garmin_open,
1575 	.close               = garmin_close,
1576 	.throttle            = garmin_throttle,
1577 	.unthrottle          = garmin_unthrottle,
1578 	.attach              = garmin_attach,
1579 	.shutdown            = garmin_shutdown,
1580 	.write               = garmin_write,
1581 	.write_room          = garmin_write_room,
1582 	.chars_in_buffer     = garmin_chars_in_buffer,
1583 	.write_bulk_callback = garmin_write_bulk_callback,
1584 	.read_bulk_callback  = garmin_read_bulk_callback,
1585 	.read_int_callback   = garmin_read_int_callback,
1586 };
1587 
1588 
1589 
1590 static int __init garmin_init (void)
1591 {
1592 	int retval;
1593 
1594 	retval = usb_serial_register(&garmin_device);
1595 	if (retval)
1596 		goto failed_garmin_register;
1597 	retval = usb_register(&garmin_driver);
1598 	if (retval)
1599 		goto failed_usb_register;
1600 	info(DRIVER_DESC " " DRIVER_VERSION);
1601 
1602 	return 0;
1603 failed_usb_register:
1604 	usb_serial_deregister(&garmin_device);
1605 failed_garmin_register:
1606 	return retval;
1607 }
1608 
1609 
1610 static void __exit garmin_exit (void)
1611 {
1612 	usb_deregister (&garmin_driver);
1613 	usb_serial_deregister (&garmin_device);
1614 }
1615 
1616 
1617 
1618 
1619 module_init(garmin_init);
1620 module_exit(garmin_exit);
1621 
1622 MODULE_AUTHOR( DRIVER_AUTHOR );
1623 MODULE_DESCRIPTION( DRIVER_DESC );
1624 MODULE_LICENSE("GPL");
1625 
1626 module_param(debug, bool, S_IWUSR | S_IRUGO);
1627 MODULE_PARM_DESC(debug, "Debug enabled or not");
1628 module_param(initial_mode, int, S_IRUGO);
1629 MODULE_PARM_DESC(initial_mode, "Initial mode");
1630 
1631