xref: /linux/drivers/usb/serial/garmin_gps.c (revision 4237c09a63906b980741725da63f85e454caec02)
1 /*
2  * Garmin GPS driver
3  *
4  * Copyright (C) 2006-2011 Hermann Kneissel herkne@gmx.de
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 <linux/uaccess.h>
37 #include <linux/atomic.h>
38 #include <linux/usb.h>
39 #include <linux/usb/serial.h>
40 
41 /* the mode to be set when the port ist opened */
42 static int initial_mode = 1;
43 
44 #define GARMIN_VENDOR_ID             0x091E
45 
46 /*
47  * Version Information
48  */
49 
50 #define VERSION_MAJOR	0
51 #define VERSION_MINOR	36
52 
53 #define _STR(s) #s
54 #define _DRIVER_VERSION(a, b) "v" _STR(a) "." _STR(b)
55 #define DRIVER_VERSION _DRIVER_VERSION(VERSION_MAJOR, VERSION_MINOR)
56 #define DRIVER_AUTHOR "hermann kneissel"
57 #define DRIVER_DESC "garmin gps driver"
58 
59 /* error codes returned by the driver */
60 #define EINVPKT	1000	/* invalid packet structure */
61 
62 
63 /* size of the header of a packet using the usb protocol */
64 #define GARMIN_PKTHDR_LENGTH	12
65 
66 /* max. possible size of a packet using the serial protocol */
67 #define MAX_SERIAL_PKT_SIZ (3 + 255 + 3)
68 
69 /*  max. possible size of a packet with worst case stuffing */
70 #define MAX_SERIAL_PKT_SIZ_STUFFED (MAX_SERIAL_PKT_SIZ + 256)
71 
72 /* size of a buffer able to hold a complete (no stuffing) packet
73  * (the document protocol does not contain packets with a larger
74  *  size, but in theory a packet may be 64k+12 bytes - if in
75  *  later protocol versions larger packet sizes occur, this value
76  *  should be increased accordingly, so the input buffer is always
77  *  large enough the store a complete packet inclusive header) */
78 #define GPS_IN_BUFSIZ  (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ)
79 
80 /* size of a buffer able to hold a complete (incl. stuffing) packet */
81 #define GPS_OUT_BUFSIZ (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ_STUFFED)
82 
83 /* where to place the packet id of a serial packet, so we can
84  * prepend the usb-packet header without the need to move the
85  * packets data */
86 #define GSP_INITIAL_OFFSET (GARMIN_PKTHDR_LENGTH-2)
87 
88 /* max. size of incoming private packets (header+1 param) */
89 #define PRIVPKTSIZ (GARMIN_PKTHDR_LENGTH+4)
90 
91 #define GARMIN_LAYERID_TRANSPORT  0
92 #define GARMIN_LAYERID_APPL      20
93 /* our own layer-id to use for some control mechanisms */
94 #define GARMIN_LAYERID_PRIVATE	0x01106E4B
95 
96 #define GARMIN_PKTID_PVT_DATA	51
97 #define GARMIN_PKTID_L001_COMMAND_DATA 10
98 
99 #define CMND_ABORT_TRANSFER 0
100 
101 /* packet ids used in private layer */
102 #define PRIV_PKTID_SET_DEBUG	1
103 #define PRIV_PKTID_SET_MODE	2
104 #define PRIV_PKTID_INFO_REQ	3
105 #define PRIV_PKTID_INFO_RESP	4
106 #define PRIV_PKTID_RESET_REQ	5
107 #define PRIV_PKTID_SET_DEF_MODE	6
108 
109 
110 #define ETX	0x03
111 #define DLE	0x10
112 #define ACK	0x06
113 #define NAK	0x15
114 
115 /* structure used to queue incoming packets */
116 struct garmin_packet {
117 	struct list_head  list;
118 	int               seq;
119 	/* the real size of the data array, always > 0 */
120 	int               size;
121 	__u8              data[1];
122 };
123 
124 /* structure used to keep the current state of the driver */
125 struct garmin_data {
126 	__u8   state;
127 	__u16  flags;
128 	__u8   mode;
129 	__u8   count;
130 	__u8   pkt_id;
131 	__u32  serial_num;
132 	struct timer_list timer;
133 	struct usb_serial_port *port;
134 	int    seq_counter;
135 	int    insize;
136 	int    outsize;
137 	__u8   inbuffer [GPS_IN_BUFSIZ];  /* tty -> usb */
138 	__u8   outbuffer[GPS_OUT_BUFSIZ]; /* usb -> tty */
139 	__u8   privpkt[4*6];
140 	spinlock_t lock;
141 	struct list_head pktlist;
142 };
143 
144 
145 #define STATE_NEW            0
146 #define STATE_INITIAL_DELAY  1
147 #define STATE_TIMEOUT        2
148 #define STATE_SESSION_REQ1   3
149 #define STATE_SESSION_REQ2   4
150 #define STATE_ACTIVE         5
151 
152 #define STATE_RESET	     8
153 #define STATE_DISCONNECTED   9
154 #define STATE_WAIT_TTY_ACK  10
155 #define STATE_GSP_WAIT_DATA 11
156 
157 #define MODE_NATIVE          0
158 #define MODE_GARMIN_SERIAL   1
159 
160 /* Flags used in garmin_data.flags: */
161 #define FLAGS_SESSION_REPLY_MASK  0x00C0
162 #define FLAGS_SESSION_REPLY1_SEEN 0x0080
163 #define FLAGS_SESSION_REPLY2_SEEN 0x0040
164 #define FLAGS_BULK_IN_ACTIVE      0x0020
165 #define FLAGS_BULK_IN_RESTART     0x0010
166 #define FLAGS_THROTTLED           0x0008
167 #define APP_REQ_SEEN              0x0004
168 #define APP_RESP_SEEN             0x0002
169 #define CLEAR_HALT_REQUIRED       0x0001
170 
171 #define FLAGS_QUEUING             0x0100
172 #define FLAGS_DROP_DATA           0x0800
173 
174 #define FLAGS_GSP_SKIP            0x1000
175 #define FLAGS_GSP_DLESEEN         0x2000
176 
177 
178 
179 
180 
181 
182 /* function prototypes */
183 static int gsp_next_packet(struct garmin_data *garmin_data_p);
184 static int garmin_write_bulk(struct usb_serial_port *port,
185 			     const unsigned char *buf, int count,
186 			     int dismiss_ack);
187 
188 /* some special packets to be send or received */
189 static unsigned char const GARMIN_START_SESSION_REQ[]
190 	= { 0, 0, 0, 0,  5, 0, 0, 0, 0, 0, 0, 0 };
191 static unsigned char const GARMIN_START_SESSION_REPLY[]
192 	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
193 static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
194 	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
195 static unsigned char const GARMIN_APP_LAYER_REPLY[]
196 	= { 0x14, 0, 0, 0 };
197 static unsigned char const GARMIN_START_PVT_REQ[]
198 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
199 static unsigned char const GARMIN_STOP_PVT_REQ[]
200 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
201 static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
202 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
203 static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
204 	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
205 static unsigned char const PRIVATE_REQ[]
206 	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };
207 
208 
209 
210 static const struct usb_device_id id_table[] = {
211 	/* the same device id seems to be used by all
212 	   usb enabled GPS devices */
213 	{ USB_DEVICE(GARMIN_VENDOR_ID, 3) },
214 	{ }					/* Terminating entry */
215 };
216 MODULE_DEVICE_TABLE(usb, id_table);
217 
218 
219 static inline int getLayerId(const __u8 *usbPacket)
220 {
221 	return __le32_to_cpup((__le32 *)(usbPacket));
222 }
223 
224 static inline int getPacketId(const __u8 *usbPacket)
225 {
226 	return __le32_to_cpup((__le32 *)(usbPacket+4));
227 }
228 
229 static inline int getDataLength(const __u8 *usbPacket)
230 {
231 	return __le32_to_cpup((__le32 *)(usbPacket+8));
232 }
233 
234 
235 /*
236  * check if the usb-packet in buf contains an abort-transfer command.
237  * (if yes, all queued data will be dropped)
238  */
239 static inline int isAbortTrfCmnd(const unsigned char *buf)
240 {
241 	if (0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ,
242 					sizeof(GARMIN_STOP_TRANSFER_REQ)) ||
243 	    0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2,
244 					sizeof(GARMIN_STOP_TRANSFER_REQ_V2)))
245 		return 1;
246 	else
247 		return 0;
248 }
249 
250 
251 
252 static void send_to_tty(struct usb_serial_port *port,
253 			char *data, unsigned int actual_length)
254 {
255 	if (actual_length) {
256 		usb_serial_debug_data(&port->dev, __func__, actual_length, data);
257 		tty_insert_flip_string(&port->port, data, actual_length);
258 		tty_flip_buffer_push(&port->port);
259 	}
260 }
261 
262 
263 /******************************************************************************
264  * packet queue handling
265  ******************************************************************************/
266 
267 /*
268  * queue a received (usb-)packet for later processing
269  */
270 static int pkt_add(struct garmin_data *garmin_data_p,
271 		   unsigned char *data, unsigned int data_length)
272 {
273 	int state = 0;
274 	int result = 0;
275 	unsigned long flags;
276 	struct garmin_packet *pkt;
277 
278 	/* process only packets containg data ... */
279 	if (data_length) {
280 		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
281 								GFP_ATOMIC);
282 		if (pkt == NULL) {
283 			dev_err(&garmin_data_p->port->dev, "out of memory\n");
284 			return 0;
285 		}
286 		pkt->size = data_length;
287 		memcpy(pkt->data, data, data_length);
288 
289 		spin_lock_irqsave(&garmin_data_p->lock, flags);
290 		garmin_data_p->flags |= FLAGS_QUEUING;
291 		result = list_empty(&garmin_data_p->pktlist);
292 		pkt->seq = garmin_data_p->seq_counter++;
293 		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
294 		state = garmin_data_p->state;
295 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
296 
297 		dev_dbg(&garmin_data_p->port->dev,
298 			"%s - added: pkt: %d - %d bytes\n", __func__,
299 			pkt->seq, data_length);
300 
301 		/* in serial mode, if someone is waiting for data from
302 		   the device, convert and send the next packet to tty. */
303 		if (result && (state == STATE_GSP_WAIT_DATA))
304 			gsp_next_packet(garmin_data_p);
305 	}
306 	return result;
307 }
308 
309 
310 /* get the next pending packet */
311 static struct garmin_packet *pkt_pop(struct garmin_data *garmin_data_p)
312 {
313 	unsigned long flags;
314 	struct garmin_packet *result = NULL;
315 
316 	spin_lock_irqsave(&garmin_data_p->lock, flags);
317 	if (!list_empty(&garmin_data_p->pktlist)) {
318 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
319 		list_del(&result->list);
320 	}
321 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
322 	return result;
323 }
324 
325 
326 /* free up all queued data */
327 static void pkt_clear(struct garmin_data *garmin_data_p)
328 {
329 	unsigned long flags;
330 	struct garmin_packet *result = NULL;
331 
332 	spin_lock_irqsave(&garmin_data_p->lock, flags);
333 	while (!list_empty(&garmin_data_p->pktlist)) {
334 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
335 		list_del(&result->list);
336 		kfree(result);
337 	}
338 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
339 }
340 
341 
342 /******************************************************************************
343  * garmin serial protocol handling handling
344  ******************************************************************************/
345 
346 /* send an ack packet back to the tty */
347 static int gsp_send_ack(struct garmin_data *garmin_data_p, __u8 pkt_id)
348 {
349 	__u8 pkt[10];
350 	__u8 cksum = 0;
351 	__u8 *ptr = pkt;
352 	unsigned  l = 0;
353 
354 	dev_dbg(&garmin_data_p->port->dev, "%s - pkt-id: 0x%X.\n", __func__,
355 		0xFF & pkt_id);
356 
357 	*ptr++ = DLE;
358 	*ptr++ = ACK;
359 	cksum += ACK;
360 
361 	*ptr++ = 2;
362 	cksum += 2;
363 
364 	*ptr++ = pkt_id;
365 	cksum += pkt_id;
366 
367 	if (pkt_id == DLE)
368 		*ptr++ = DLE;
369 
370 	*ptr++ = 0;
371 	*ptr++ = 0xFF & (-cksum);
372 	*ptr++ = DLE;
373 	*ptr++ = ETX;
374 
375 	l = ptr-pkt;
376 
377 	send_to_tty(garmin_data_p->port, pkt, l);
378 	return 0;
379 }
380 
381 
382 
383 /*
384  * called for a complete packet received from tty layer
385  *
386  * the complete packet (pktid ... cksum) is in garmin_data_p->inbuf starting
387  * at GSP_INITIAL_OFFSET.
388  *
389  * count - number of bytes in the input buffer including space reserved for
390  *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet
391  *         (including pkt-id, data-length a. cksum)
392  */
393 static int gsp_rec_packet(struct garmin_data *garmin_data_p, int count)
394 {
395 	struct device *dev = &garmin_data_p->port->dev;
396 	unsigned long flags;
397 	const __u8 *recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
398 	__le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;
399 	int cksum = 0;
400 	int n = 0;
401 	int pktid = recpkt[0];
402 	int size = recpkt[1];
403 
404 	usb_serial_debug_data(&garmin_data_p->port->dev, __func__,
405 			      count-GSP_INITIAL_OFFSET, recpkt);
406 
407 	if (size != (count-GSP_INITIAL_OFFSET-3)) {
408 		dev_dbg(dev, "%s - invalid size, expected %d bytes, got %d\n",
409 			__func__, size, (count-GSP_INITIAL_OFFSET-3));
410 		return -EINVPKT;
411 	}
412 
413 	cksum += *recpkt++;
414 	cksum += *recpkt++;
415 
416 	/* sanity check, remove after test ... */
417 	if ((__u8 *)&(usbdata[3]) != recpkt) {
418 		dev_dbg(dev, "%s - ptr mismatch %p - %p\n", __func__,
419 			&(usbdata[4]), recpkt);
420 		return -EINVPKT;
421 	}
422 
423 	while (n < size) {
424 		cksum += *recpkt++;
425 		n++;
426 	}
427 
428 	if ((0xff & (cksum + *recpkt)) != 0) {
429 		dev_dbg(dev, "%s - invalid checksum, expected %02x, got %02x\n",
430 			__func__, 0xff & -cksum, 0xff & *recpkt);
431 		return -EINVPKT;
432 	}
433 
434 	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
435 	usbdata[1] = __cpu_to_le32(pktid);
436 	usbdata[2] = __cpu_to_le32(size);
437 
438 	garmin_write_bulk(garmin_data_p->port, garmin_data_p->inbuffer,
439 			   GARMIN_PKTHDR_LENGTH+size, 0);
440 
441 	/* if this was an abort-transfer command, flush all
442 	   queued data. */
443 	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
444 		spin_lock_irqsave(&garmin_data_p->lock, flags);
445 		garmin_data_p->flags |= FLAGS_DROP_DATA;
446 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
447 		pkt_clear(garmin_data_p);
448 	}
449 
450 	return count;
451 }
452 
453 
454 
455 /*
456  * Called for data received from tty
457  *
458  * buf contains the data read, it may span more than one packet or even
459  * incomplete packets
460  *
461  * input record should be a serial-record, but it may not be complete.
462  * Copy it into our local buffer, until an etx is seen (or an error
463  * occurs).
464  * Once the record is complete, convert into a usb packet and send it
465  * to the bulk pipe, send an ack back to the tty.
466  *
467  * If the input is an ack, just send the last queued packet to the
468  * tty layer.
469  *
470  * if the input is an abort command, drop all queued data.
471  */
472 
473 static int gsp_receive(struct garmin_data *garmin_data_p,
474 		       const unsigned char *buf, int count)
475 {
476 	struct device *dev = &garmin_data_p->port->dev;
477 	unsigned long flags;
478 	int offs = 0;
479 	int ack_or_nak_seen = 0;
480 	__u8 *dest;
481 	int size;
482 	/* dleSeen: set if last byte read was a DLE */
483 	int dleSeen;
484 	/* skip: if set, skip incoming data until possible start of
485 	 *       new packet
486 	 */
487 	int skip;
488 	__u8 data;
489 
490 	spin_lock_irqsave(&garmin_data_p->lock, flags);
491 	dest = garmin_data_p->inbuffer;
492 	size = garmin_data_p->insize;
493 	dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
494 	skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
495 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
496 
497 	/* dev_dbg(dev, "%s - dle=%d skip=%d size=%d count=%d\n",
498 		__func__, dleSeen, skip, size, count); */
499 
500 	if (size == 0)
501 		size = GSP_INITIAL_OFFSET;
502 
503 	while (offs < count) {
504 
505 		data = *(buf+offs);
506 		offs++;
507 
508 		if (data == DLE) {
509 			if (skip) { /* start of a new pkt */
510 				skip = 0;
511 				size = GSP_INITIAL_OFFSET;
512 				dleSeen = 1;
513 			} else if (dleSeen) {
514 				dest[size++] = data;
515 				dleSeen = 0;
516 			} else {
517 				dleSeen = 1;
518 			}
519 		} else if (data == ETX) {
520 			if (dleSeen) {
521 				/* packet complete */
522 
523 				data = dest[GSP_INITIAL_OFFSET];
524 
525 				if (data == ACK) {
526 					ack_or_nak_seen = ACK;
527 					dev_dbg(dev, "ACK packet complete.\n");
528 				} else if (data == NAK) {
529 					ack_or_nak_seen = NAK;
530 					dev_dbg(dev, "NAK packet complete.\n");
531 				} else {
532 					dev_dbg(dev, "packet complete - id=0x%X.\n",
533 						0xFF & data);
534 					gsp_rec_packet(garmin_data_p, size);
535 				}
536 
537 				skip = 1;
538 				size = GSP_INITIAL_OFFSET;
539 				dleSeen = 0;
540 			} else {
541 				dest[size++] = data;
542 			}
543 		} else if (!skip) {
544 
545 			if (dleSeen) {
546 				size = GSP_INITIAL_OFFSET;
547 				dleSeen = 0;
548 			}
549 
550 			dest[size++] = data;
551 		}
552 
553 		if (size >= GPS_IN_BUFSIZ) {
554 			dev_dbg(dev, "%s - packet too large.\n", __func__);
555 			skip = 1;
556 			size = GSP_INITIAL_OFFSET;
557 			dleSeen = 0;
558 		}
559 	}
560 
561 	spin_lock_irqsave(&garmin_data_p->lock, flags);
562 
563 	garmin_data_p->insize = size;
564 
565 	/* copy flags back to structure */
566 	if (skip)
567 		garmin_data_p->flags |= FLAGS_GSP_SKIP;
568 	else
569 		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;
570 
571 	if (dleSeen)
572 		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
573 	else
574 		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;
575 
576 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
577 
578 	if (ack_or_nak_seen) {
579 		if (gsp_next_packet(garmin_data_p) > 0)
580 			garmin_data_p->state = STATE_ACTIVE;
581 		else
582 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
583 	}
584 	return count;
585 }
586 
587 
588 
589 /*
590  * Sends a usb packet to the tty
591  *
592  * Assumes, that all packages and at an usb-packet boundary.
593  *
594  * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
595  */
596 static int gsp_send(struct garmin_data *garmin_data_p,
597 		    const unsigned char *buf, int count)
598 {
599 	struct device *dev = &garmin_data_p->port->dev;
600 	const unsigned char *src;
601 	unsigned char *dst;
602 	int pktid = 0;
603 	int datalen = 0;
604 	int cksum = 0;
605 	int i = 0;
606 	int k;
607 
608 	dev_dbg(dev, "%s - state %d - %d bytes.\n", __func__,
609 		garmin_data_p->state, count);
610 
611 	k = garmin_data_p->outsize;
612 	if ((k+count) > GPS_OUT_BUFSIZ) {
613 		dev_dbg(dev, "packet too large\n");
614 		garmin_data_p->outsize = 0;
615 		return -4;
616 	}
617 
618 	memcpy(garmin_data_p->outbuffer+k, buf, count);
619 	k += count;
620 	garmin_data_p->outsize = k;
621 
622 	if (k >= GARMIN_PKTHDR_LENGTH) {
623 		pktid  = getPacketId(garmin_data_p->outbuffer);
624 		datalen = getDataLength(garmin_data_p->outbuffer);
625 		i = GARMIN_PKTHDR_LENGTH + datalen;
626 		if (k < i)
627 			return 0;
628 	} else {
629 		return 0;
630 	}
631 
632 	dev_dbg(dev, "%s - %d bytes in buffer, %d bytes in pkt.\n", __func__, k, i);
633 
634 	/* garmin_data_p->outbuffer now contains a complete packet */
635 
636 	usb_serial_debug_data(&garmin_data_p->port->dev, __func__, k,
637 			      garmin_data_p->outbuffer);
638 
639 	garmin_data_p->outsize = 0;
640 
641 	if (GARMIN_LAYERID_APPL != getLayerId(garmin_data_p->outbuffer)) {
642 		dev_dbg(dev, "not an application packet (%d)\n",
643 				getLayerId(garmin_data_p->outbuffer));
644 		return -1;
645 	}
646 
647 	if (pktid > 255) {
648 		dev_dbg(dev, "packet-id %d too large\n", pktid);
649 		return -2;
650 	}
651 
652 	if (datalen > 255) {
653 		dev_dbg(dev, "packet-size %d too large\n", datalen);
654 		return -3;
655 	}
656 
657 	/* the serial protocol should be able to handle this packet */
658 
659 	k = 0;
660 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
661 	for (i = 0; i < datalen; i++) {
662 		if (*src++ == DLE)
663 			k++;
664 	}
665 
666 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
667 	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
668 		/* can't add stuffing DLEs in place, move data to end
669 		   of buffer ... */
670 		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
671 		memcpy(dst, src, datalen);
672 		src = dst;
673 	}
674 
675 	dst = garmin_data_p->outbuffer;
676 
677 	*dst++ = DLE;
678 	*dst++ = pktid;
679 	cksum += pktid;
680 	*dst++ = datalen;
681 	cksum += datalen;
682 	if (datalen == DLE)
683 		*dst++ = DLE;
684 
685 	for (i = 0; i < datalen; i++) {
686 		__u8 c = *src++;
687 		*dst++ = c;
688 		cksum += c;
689 		if (c == DLE)
690 			*dst++ = DLE;
691 	}
692 
693 	cksum = 0xFF & -cksum;
694 	*dst++ = cksum;
695 	if (cksum == DLE)
696 		*dst++ = DLE;
697 	*dst++ = DLE;
698 	*dst++ = ETX;
699 
700 	i = dst-garmin_data_p->outbuffer;
701 
702 	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);
703 
704 	garmin_data_p->pkt_id = pktid;
705 	garmin_data_p->state  = STATE_WAIT_TTY_ACK;
706 
707 	return i;
708 }
709 
710 
711 /*
712  * Process the next pending data packet - if there is one
713  */
714 static int gsp_next_packet(struct garmin_data *garmin_data_p)
715 {
716 	int result = 0;
717 	struct garmin_packet *pkt = NULL;
718 
719 	while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
720 		dev_dbg(&garmin_data_p->port->dev, "%s - next pkt: %d\n", __func__, pkt->seq);
721 		result = gsp_send(garmin_data_p, pkt->data, pkt->size);
722 		if (result > 0) {
723 			kfree(pkt);
724 			return result;
725 		}
726 		kfree(pkt);
727 	}
728 	return result;
729 }
730 
731 
732 
733 /******************************************************************************
734  * garmin native mode
735  ******************************************************************************/
736 
737 
738 /*
739  * Called for data received from tty
740  *
741  * The input data is expected to be in garmin usb-packet format.
742  *
743  * buf contains the data read, it may span more than one packet
744  * or even incomplete packets
745  */
746 static int nat_receive(struct garmin_data *garmin_data_p,
747 		       const unsigned char *buf, int count)
748 {
749 	unsigned long flags;
750 	__u8 *dest;
751 	int offs = 0;
752 	int result = count;
753 	int len;
754 
755 	while (offs < count) {
756 		/* if buffer contains header, copy rest of data */
757 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
758 			len = GARMIN_PKTHDR_LENGTH
759 			      +getDataLength(garmin_data_p->inbuffer);
760 		else
761 			len = GARMIN_PKTHDR_LENGTH;
762 
763 		if (len >= GPS_IN_BUFSIZ) {
764 			/* seems to be an invalid packet, ignore rest
765 			   of input */
766 			dev_dbg(&garmin_data_p->port->dev,
767 				"%s - packet size too large: %d\n",
768 				__func__, len);
769 			garmin_data_p->insize = 0;
770 			count = 0;
771 			result = -EINVPKT;
772 		} else {
773 			len -= garmin_data_p->insize;
774 			if (len > (count-offs))
775 				len = (count-offs);
776 			if (len > 0) {
777 				dest = garmin_data_p->inbuffer
778 						+ garmin_data_p->insize;
779 				memcpy(dest, buf+offs, len);
780 				garmin_data_p->insize += len;
781 				offs += len;
782 			}
783 		}
784 
785 		/* do we have a complete packet ? */
786 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
787 			len = GARMIN_PKTHDR_LENGTH+
788 			   getDataLength(garmin_data_p->inbuffer);
789 			if (garmin_data_p->insize >= len) {
790 				garmin_write_bulk(garmin_data_p->port,
791 						   garmin_data_p->inbuffer,
792 						   len, 0);
793 				garmin_data_p->insize = 0;
794 
795 				/* if this was an abort-transfer command,
796 				   flush all queued data. */
797 				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
798 					spin_lock_irqsave(&garmin_data_p->lock,
799 									flags);
800 					garmin_data_p->flags |= FLAGS_DROP_DATA;
801 					spin_unlock_irqrestore(
802 						&garmin_data_p->lock, flags);
803 					pkt_clear(garmin_data_p);
804 				}
805 			}
806 		}
807 	}
808 	return result;
809 }
810 
811 
812 /******************************************************************************
813  * private packets
814  ******************************************************************************/
815 
816 static void priv_status_resp(struct usb_serial_port *port)
817 {
818 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
819 	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;
820 
821 	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
822 	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
823 	pkt[2] = __cpu_to_le32(12);
824 	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
825 	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
826 	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);
827 
828 	send_to_tty(port, (__u8 *)pkt, 6 * 4);
829 }
830 
831 
832 /******************************************************************************
833  * Garmin specific driver functions
834  ******************************************************************************/
835 
836 static int process_resetdev_request(struct usb_serial_port *port)
837 {
838 	unsigned long flags;
839 	int status;
840 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
841 
842 	spin_lock_irqsave(&garmin_data_p->lock, flags);
843 	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
844 	garmin_data_p->state = STATE_RESET;
845 	garmin_data_p->serial_num = 0;
846 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
847 
848 	usb_kill_urb(port->interrupt_in_urb);
849 	dev_dbg(&port->dev, "%s - usb_reset_device\n", __func__);
850 	status = usb_reset_device(port->serial->dev);
851 	if (status)
852 		dev_dbg(&port->dev, "%s - usb_reset_device failed: %d\n",
853 			__func__, status);
854 	return status;
855 }
856 
857 
858 
859 /*
860  * clear all cached data
861  */
862 static int garmin_clear(struct garmin_data *garmin_data_p)
863 {
864 	unsigned long flags;
865 	int status = 0;
866 
867 	/* flush all queued data */
868 	pkt_clear(garmin_data_p);
869 
870 	spin_lock_irqsave(&garmin_data_p->lock, flags);
871 	garmin_data_p->insize = 0;
872 	garmin_data_p->outsize = 0;
873 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
874 
875 	return status;
876 }
877 
878 
879 static int garmin_init_session(struct usb_serial_port *port)
880 {
881 	struct usb_serial *serial = port->serial;
882 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
883 	int status = 0;
884 	int i = 0;
885 
886 	if (status == 0) {
887 		usb_kill_urb(port->interrupt_in_urb);
888 
889 		dev_dbg(&serial->dev->dev, "%s - adding interrupt input\n", __func__);
890 		status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
891 		if (status)
892 			dev_err(&serial->dev->dev,
893 			  "%s - failed submitting interrupt urb, error %d\n",
894 							__func__, status);
895 	}
896 
897 	/*
898 	 * using the initialization method from gpsbabel. See comments in
899 	 * gpsbabel/jeeps/gpslibusb.c gusb_reset_toggles()
900 	 */
901 	if (status == 0) {
902 		dev_dbg(&serial->dev->dev, "%s - starting session ...\n", __func__);
903 		garmin_data_p->state = STATE_ACTIVE;
904 
905 		for (i = 0; i < 3; i++) {
906 			status = garmin_write_bulk(port,
907 					GARMIN_START_SESSION_REQ,
908 					sizeof(GARMIN_START_SESSION_REQ), 0);
909 
910 			if (status < 0)
911 				break;
912 		}
913 
914 		if (status > 0)
915 			status = 0;
916 	}
917 
918 	return status;
919 }
920 
921 
922 
923 static int garmin_open(struct tty_struct *tty, struct usb_serial_port *port)
924 {
925 	unsigned long flags;
926 	int status = 0;
927 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
928 
929 	spin_lock_irqsave(&garmin_data_p->lock, flags);
930 	garmin_data_p->mode  = initial_mode;
931 	garmin_data_p->count = 0;
932 	garmin_data_p->flags &= FLAGS_SESSION_REPLY1_SEEN;
933 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
934 
935 	/* shutdown any bulk reads that might be going on */
936 	usb_kill_urb(port->write_urb);
937 	usb_kill_urb(port->read_urb);
938 
939 	if (garmin_data_p->state == STATE_RESET)
940 		status = garmin_init_session(port);
941 
942 	garmin_data_p->state = STATE_ACTIVE;
943 	return status;
944 }
945 
946 
947 static void garmin_close(struct usb_serial_port *port)
948 {
949 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
950 
951 	dev_dbg(&port->dev, "%s - port %d - mode=%d state=%d flags=0x%X\n",
952 		__func__, port->number, garmin_data_p->mode,
953 		garmin_data_p->state, garmin_data_p->flags);
954 
955 	garmin_clear(garmin_data_p);
956 
957 	/* shutdown our urbs */
958 	usb_kill_urb(port->read_urb);
959 	usb_kill_urb(port->write_urb);
960 
961 	/* keep reset state so we know that we must start a new session */
962 	if (garmin_data_p->state != STATE_RESET)
963 		garmin_data_p->state = STATE_DISCONNECTED;
964 }
965 
966 
967 static void garmin_write_bulk_callback(struct urb *urb)
968 {
969 	struct usb_serial_port *port = urb->context;
970 
971 	if (port) {
972 		struct garmin_data *garmin_data_p =
973 					usb_get_serial_port_data(port);
974 
975 		if (GARMIN_LAYERID_APPL == getLayerId(urb->transfer_buffer)) {
976 
977 			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
978 				gsp_send_ack(garmin_data_p,
979 					((__u8 *)urb->transfer_buffer)[4]);
980 			}
981 		}
982 		usb_serial_port_softint(port);
983 	}
984 
985 	/* Ignore errors that resulted from garmin_write_bulk with
986 	   dismiss_ack = 1 */
987 
988 	/* free up the transfer buffer, as usb_free_urb() does not do this */
989 	kfree(urb->transfer_buffer);
990 }
991 
992 
993 static int garmin_write_bulk(struct usb_serial_port *port,
994 			      const unsigned char *buf, int count,
995 			      int dismiss_ack)
996 {
997 	unsigned long flags;
998 	struct usb_serial *serial = port->serial;
999 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1000 	struct urb *urb;
1001 	unsigned char *buffer;
1002 	int status;
1003 
1004 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1005 	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
1006 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1007 
1008 	buffer = kmalloc(count, GFP_ATOMIC);
1009 	if (!buffer) {
1010 		dev_err(&port->dev, "out of memory\n");
1011 		return -ENOMEM;
1012 	}
1013 
1014 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1015 	if (!urb) {
1016 		dev_err(&port->dev, "no more free urbs\n");
1017 		kfree(buffer);
1018 		return -ENOMEM;
1019 	}
1020 
1021 	memcpy(buffer, buf, count);
1022 
1023 	usb_serial_debug_data(&port->dev, __func__, count, buffer);
1024 
1025 	usb_fill_bulk_urb(urb, serial->dev,
1026 				usb_sndbulkpipe(serial->dev,
1027 					port->bulk_out_endpointAddress),
1028 				buffer, count,
1029 				garmin_write_bulk_callback,
1030 				dismiss_ack ? NULL : port);
1031 	urb->transfer_flags |= URB_ZERO_PACKET;
1032 
1033 	if (GARMIN_LAYERID_APPL == getLayerId(buffer)) {
1034 
1035 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1036 		garmin_data_p->flags |= APP_REQ_SEEN;
1037 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1038 
1039 		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
1040 			pkt_clear(garmin_data_p);
1041 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
1042 		}
1043 	}
1044 
1045 	/* send it down the pipe */
1046 	status = usb_submit_urb(urb, GFP_ATOMIC);
1047 	if (status) {
1048 		dev_err(&port->dev,
1049 		   "%s - usb_submit_urb(write bulk) failed with status = %d\n",
1050 				__func__, status);
1051 		count = status;
1052 	}
1053 
1054 	/* we are done with this urb, so let the host driver
1055 	 * really free it when it is finished with it */
1056 	usb_free_urb(urb);
1057 
1058 	return count;
1059 }
1060 
1061 static int garmin_write(struct tty_struct *tty, struct usb_serial_port *port,
1062 					 const unsigned char *buf, int count)
1063 {
1064 	struct device *dev = &port->dev;
1065 	int pktid, pktsiz, len;
1066 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1067 	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;
1068 
1069 	usb_serial_debug_data(dev, __func__, count, buf);
1070 
1071 	if (garmin_data_p->state == STATE_RESET)
1072 		return -EIO;
1073 
1074 	/* check for our private packets */
1075 	if (count >= GARMIN_PKTHDR_LENGTH) {
1076 		len = PRIVPKTSIZ;
1077 		if (count < len)
1078 			len = count;
1079 
1080 		memcpy(garmin_data_p->privpkt, buf, len);
1081 
1082 		pktsiz = getDataLength(garmin_data_p->privpkt);
1083 		pktid  = getPacketId(garmin_data_p->privpkt);
1084 
1085 		if (count == (GARMIN_PKTHDR_LENGTH+pktsiz)
1086 		    && GARMIN_LAYERID_PRIVATE ==
1087 				getLayerId(garmin_data_p->privpkt)) {
1088 
1089 			dev_dbg(dev, "%s - processing private request %d\n",
1090 				__func__, pktid);
1091 
1092 			/* drop all unfinished transfers */
1093 			garmin_clear(garmin_data_p);
1094 
1095 			switch (pktid) {
1096 			case PRIV_PKTID_SET_MODE:
1097 				if (pktsiz != 4)
1098 					return -EINVPKT;
1099 				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
1100 				dev_dbg(dev, "%s - mode set to %d\n",
1101 					__func__, garmin_data_p->mode);
1102 				break;
1103 
1104 			case PRIV_PKTID_INFO_REQ:
1105 				priv_status_resp(port);
1106 				break;
1107 
1108 			case PRIV_PKTID_RESET_REQ:
1109 				process_resetdev_request(port);
1110 				break;
1111 
1112 			case PRIV_PKTID_SET_DEF_MODE:
1113 				if (pktsiz != 4)
1114 					return -EINVPKT;
1115 				initial_mode = __le32_to_cpu(privpkt[3]);
1116 				dev_dbg(dev, "%s - initial_mode set to %d\n",
1117 					__func__,
1118 					garmin_data_p->mode);
1119 				break;
1120 			}
1121 			return count;
1122 		}
1123 	}
1124 
1125 	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1126 		return gsp_receive(garmin_data_p, buf, count);
1127 	} else {	/* MODE_NATIVE */
1128 		return nat_receive(garmin_data_p, buf, count);
1129 	}
1130 }
1131 
1132 
1133 static int garmin_write_room(struct tty_struct *tty)
1134 {
1135 	struct usb_serial_port *port = tty->driver_data;
1136 	/*
1137 	 * Report back the bytes currently available in the output buffer.
1138 	 */
1139 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1140 	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
1141 }
1142 
1143 
1144 static void garmin_read_process(struct garmin_data *garmin_data_p,
1145 				 unsigned char *data, unsigned data_length,
1146 				 int bulk_data)
1147 {
1148 	unsigned long flags;
1149 
1150 	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
1151 		/* abort-transfer cmd is actice */
1152 		dev_dbg(&garmin_data_p->port->dev, "%s - pkt dropped\n", __func__);
1153 	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
1154 		garmin_data_p->state != STATE_RESET) {
1155 
1156 		/* if throttling is active or postprecessing is required
1157 		   put the received data in the input queue, otherwise
1158 		   send it directly to the tty port */
1159 		if (garmin_data_p->flags & FLAGS_QUEUING) {
1160 			pkt_add(garmin_data_p, data, data_length);
1161 		} else if (bulk_data ||
1162 			   getLayerId(data) == GARMIN_LAYERID_APPL) {
1163 
1164 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1165 			garmin_data_p->flags |= APP_RESP_SEEN;
1166 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1167 
1168 			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1169 				pkt_add(garmin_data_p, data, data_length);
1170 			} else {
1171 				send_to_tty(garmin_data_p->port, data,
1172 						data_length);
1173 			}
1174 		}
1175 		/* ignore system layer packets ... */
1176 	}
1177 }
1178 
1179 
1180 static void garmin_read_bulk_callback(struct urb *urb)
1181 {
1182 	unsigned long flags;
1183 	struct usb_serial_port *port = urb->context;
1184 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1185 	unsigned char *data = urb->transfer_buffer;
1186 	int status = urb->status;
1187 	int retval;
1188 
1189 	if (status) {
1190 		dev_dbg(&urb->dev->dev, "%s - nonzero read bulk status received: %d\n",
1191 			__func__, status);
1192 		return;
1193 	}
1194 
1195 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
1196 
1197 	garmin_read_process(garmin_data_p, data, urb->actual_length, 1);
1198 
1199 	if (urb->actual_length == 0 &&
1200 			0 != (garmin_data_p->flags & FLAGS_BULK_IN_RESTART)) {
1201 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1202 		garmin_data_p->flags &= ~FLAGS_BULK_IN_RESTART;
1203 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1204 		retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1205 		if (retval)
1206 			dev_err(&port->dev,
1207 				"%s - failed resubmitting read urb, error %d\n",
1208 				__func__, retval);
1209 	} else if (urb->actual_length > 0) {
1210 		/* Continue trying to read until nothing more is received  */
1211 		if (0 == (garmin_data_p->flags & FLAGS_THROTTLED)) {
1212 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1213 			if (retval)
1214 				dev_err(&port->dev,
1215 					"%s - failed resubmitting read urb, error %d\n",
1216 					__func__, retval);
1217 		}
1218 	} else {
1219 		dev_dbg(&port->dev, "%s - end of bulk data\n", __func__);
1220 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1221 		garmin_data_p->flags &= ~FLAGS_BULK_IN_ACTIVE;
1222 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1223 	}
1224 }
1225 
1226 
1227 static void garmin_read_int_callback(struct urb *urb)
1228 {
1229 	unsigned long flags;
1230 	int retval;
1231 	struct usb_serial_port *port = urb->context;
1232 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1233 	unsigned char *data = urb->transfer_buffer;
1234 	int status = urb->status;
1235 
1236 	switch (status) {
1237 	case 0:
1238 		/* success */
1239 		break;
1240 	case -ECONNRESET:
1241 	case -ENOENT:
1242 	case -ESHUTDOWN:
1243 		/* this urb is terminated, clean up */
1244 		dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
1245 			__func__, status);
1246 		return;
1247 	default:
1248 		dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
1249 			__func__, status);
1250 		return;
1251 	}
1252 
1253 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
1254 			      urb->transfer_buffer);
1255 
1256 	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
1257 	    0 == memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
1258 				sizeof(GARMIN_BULK_IN_AVAIL_REPLY))) {
1259 
1260 		dev_dbg(&port->dev, "%s - bulk data available.\n", __func__);
1261 
1262 		if (0 == (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1263 
1264 			/* bulk data available */
1265 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1266 			if (retval) {
1267 				dev_err(&port->dev,
1268 				 "%s - failed submitting read urb, error %d\n",
1269 							__func__, retval);
1270 			} else {
1271 				spin_lock_irqsave(&garmin_data_p->lock, flags);
1272 				garmin_data_p->flags |= FLAGS_BULK_IN_ACTIVE;
1273 				spin_unlock_irqrestore(&garmin_data_p->lock,
1274 									flags);
1275 			}
1276 		} else {
1277 			/* bulk-in transfer still active */
1278 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1279 			garmin_data_p->flags |= FLAGS_BULK_IN_RESTART;
1280 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1281 		}
1282 
1283 	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
1284 			 && 0 == memcmp(data, GARMIN_START_SESSION_REPLY,
1285 					sizeof(GARMIN_START_SESSION_REPLY))) {
1286 
1287 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1288 		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
1289 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1290 
1291 		/* save the serial number */
1292 		garmin_data_p->serial_num = __le32_to_cpup(
1293 					(__le32 *)(data+GARMIN_PKTHDR_LENGTH));
1294 
1295 		dev_dbg(&port->dev, "%s - start-of-session reply seen - serial %u.\n",
1296 			__func__, garmin_data_p->serial_num);
1297 	}
1298 
1299 	garmin_read_process(garmin_data_p, data, urb->actual_length, 0);
1300 
1301 	retval = usb_submit_urb(urb, GFP_ATOMIC);
1302 	if (retval)
1303 		dev_err(&urb->dev->dev,
1304 			"%s - Error %d submitting interrupt urb\n",
1305 			__func__, retval);
1306 }
1307 
1308 
1309 /*
1310  * Sends the next queued packt to the tty port (garmin native mode only)
1311  * and then sets a timer to call itself again until all queued data
1312  * is sent.
1313  */
1314 static int garmin_flush_queue(struct garmin_data *garmin_data_p)
1315 {
1316 	unsigned long flags;
1317 	struct garmin_packet *pkt;
1318 
1319 	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1320 		pkt = pkt_pop(garmin_data_p);
1321 		if (pkt != NULL) {
1322 			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
1323 			kfree(pkt);
1324 			mod_timer(&garmin_data_p->timer, (1)+jiffies);
1325 
1326 		} else {
1327 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1328 			garmin_data_p->flags &= ~FLAGS_QUEUING;
1329 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1330 		}
1331 	}
1332 	return 0;
1333 }
1334 
1335 
1336 static void garmin_throttle(struct tty_struct *tty)
1337 {
1338 	struct usb_serial_port *port = tty->driver_data;
1339 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1340 
1341 	/* set flag, data received will be put into a queue
1342 	   for later processing */
1343 	spin_lock_irq(&garmin_data_p->lock);
1344 	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
1345 	spin_unlock_irq(&garmin_data_p->lock);
1346 }
1347 
1348 
1349 static void garmin_unthrottle(struct tty_struct *tty)
1350 {
1351 	struct usb_serial_port *port = tty->driver_data;
1352 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1353 	int status;
1354 
1355 	spin_lock_irq(&garmin_data_p->lock);
1356 	garmin_data_p->flags &= ~FLAGS_THROTTLED;
1357 	spin_unlock_irq(&garmin_data_p->lock);
1358 
1359 	/* in native mode send queued data to tty, in
1360 	   serial mode nothing needs to be done here */
1361 	if (garmin_data_p->mode == MODE_NATIVE)
1362 		garmin_flush_queue(garmin_data_p);
1363 
1364 	if (0 != (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1365 		status = usb_submit_urb(port->read_urb, GFP_KERNEL);
1366 		if (status)
1367 			dev_err(&port->dev,
1368 				"%s - failed resubmitting read urb, error %d\n",
1369 				__func__, status);
1370 	}
1371 }
1372 
1373 /*
1374  * The timer is currently only used to send queued packets to
1375  * the tty in cases where the protocol provides no own handshaking
1376  * to initiate the transfer.
1377  */
1378 static void timeout_handler(unsigned long data)
1379 {
1380 	struct garmin_data *garmin_data_p = (struct garmin_data *) data;
1381 
1382 	/* send the next queued packet to the tty port */
1383 	if (garmin_data_p->mode == MODE_NATIVE)
1384 		if (garmin_data_p->flags & FLAGS_QUEUING)
1385 			garmin_flush_queue(garmin_data_p);
1386 }
1387 
1388 
1389 
1390 static int garmin_port_probe(struct usb_serial_port *port)
1391 {
1392 	int status;
1393 	struct garmin_data *garmin_data_p;
1394 
1395 	garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
1396 	if (garmin_data_p == NULL) {
1397 		dev_err(&port->dev, "%s - Out of memory\n", __func__);
1398 		return -ENOMEM;
1399 	}
1400 	init_timer(&garmin_data_p->timer);
1401 	spin_lock_init(&garmin_data_p->lock);
1402 	INIT_LIST_HEAD(&garmin_data_p->pktlist);
1403 	/* garmin_data_p->timer.expires = jiffies + session_timeout; */
1404 	garmin_data_p->timer.data = (unsigned long)garmin_data_p;
1405 	garmin_data_p->timer.function = timeout_handler;
1406 	garmin_data_p->port = port;
1407 	garmin_data_p->state = 0;
1408 	garmin_data_p->flags = 0;
1409 	garmin_data_p->count = 0;
1410 	usb_set_serial_port_data(port, garmin_data_p);
1411 
1412 	status = garmin_init_session(port);
1413 
1414 	return status;
1415 }
1416 
1417 
1418 static int garmin_port_remove(struct usb_serial_port *port)
1419 {
1420 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1421 
1422 	usb_kill_urb(port->interrupt_in_urb);
1423 	del_timer_sync(&garmin_data_p->timer);
1424 	kfree(garmin_data_p);
1425 	return 0;
1426 }
1427 
1428 
1429 /* All of the device info needed */
1430 static struct usb_serial_driver garmin_device = {
1431 	.driver = {
1432 		.owner       = THIS_MODULE,
1433 		.name        = "garmin_gps",
1434 	},
1435 	.description         = "Garmin GPS usb/tty",
1436 	.id_table            = id_table,
1437 	.num_ports           = 1,
1438 	.open                = garmin_open,
1439 	.close               = garmin_close,
1440 	.throttle            = garmin_throttle,
1441 	.unthrottle          = garmin_unthrottle,
1442 	.port_probe		= garmin_port_probe,
1443 	.port_remove		= garmin_port_remove,
1444 	.write               = garmin_write,
1445 	.write_room          = garmin_write_room,
1446 	.write_bulk_callback = garmin_write_bulk_callback,
1447 	.read_bulk_callback  = garmin_read_bulk_callback,
1448 	.read_int_callback   = garmin_read_int_callback,
1449 };
1450 
1451 static struct usb_serial_driver * const serial_drivers[] = {
1452 	&garmin_device, NULL
1453 };
1454 
1455 module_usb_serial_driver(serial_drivers, id_table);
1456 
1457 MODULE_AUTHOR(DRIVER_AUTHOR);
1458 MODULE_DESCRIPTION(DRIVER_DESC);
1459 MODULE_LICENSE("GPL");
1460 
1461 module_param(initial_mode, int, S_IRUGO);
1462 MODULE_PARM_DESC(initial_mode, "Initial mode");
1463