xref: /linux/drivers/usb/serial/garmin_gps.c (revision 838632438145ac6863377eb12d8b8eef9c55d288)
1 /*
2  * Garmin GPS driver
3  *
4  * Copyright (C) 2006-2009 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 <linux/uaccess.h>
37 #include <asm/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 /* debug flag */
45 static int debug;
46 
47 #define GARMIN_VENDOR_ID             0x091E
48 
49 /*
50  * Version Information
51  */
52 
53 #define VERSION_MAJOR	0
54 #define VERSION_MINOR	33
55 
56 #define _STR(s) #s
57 #define _DRIVER_VERSION(a, b) "v" _STR(a) "." _STR(b)
58 #define DRIVER_VERSION _DRIVER_VERSION(VERSION_MAJOR, VERSION_MINOR)
59 #define DRIVER_AUTHOR "hermann kneissel"
60 #define DRIVER_DESC "garmin gps driver"
61 
62 /* error codes returned by the driver */
63 #define EINVPKT	1000	/* invalid packet structure */
64 
65 
66 /* size of the header of a packet using the usb protocol */
67 #define GARMIN_PKTHDR_LENGTH	12
68 
69 /* max. possible size of a packet using the serial protocol */
70 #define MAX_SERIAL_PKT_SIZ (3 + 255 + 3)
71 
72 /*  max. possible size of a packet with worst case stuffing */
73 #define MAX_SERIAL_PKT_SIZ_STUFFED (MAX_SERIAL_PKT_SIZ + 256)
74 
75 /* size of a buffer able to hold a complete (no stuffing) packet
76  * (the document protocol does not contain packets with a larger
77  *  size, but in theory a packet may be 64k+12 bytes - if in
78  *  later protocol versions larger packet sizes occur, this value
79  *  should be increased accordingly, so the input buffer is always
80  *  large enough the store a complete packet inclusive header) */
81 #define GPS_IN_BUFSIZ  (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ)
82 
83 /* size of a buffer able to hold a complete (incl. stuffing) packet */
84 #define GPS_OUT_BUFSIZ (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ_STUFFED)
85 
86 /* where to place the packet id of a serial packet, so we can
87  * prepend the usb-packet header without the need to move the
88  * packets data */
89 #define GSP_INITIAL_OFFSET (GARMIN_PKTHDR_LENGTH-2)
90 
91 /* max. size of incoming private packets (header+1 param) */
92 #define PRIVPKTSIZ (GARMIN_PKTHDR_LENGTH+4)
93 
94 #define GARMIN_LAYERID_TRANSPORT  0
95 #define GARMIN_LAYERID_APPL      20
96 /* our own layer-id to use for some control mechanisms */
97 #define GARMIN_LAYERID_PRIVATE	0x01106E4B
98 
99 #define GARMIN_PKTID_PVT_DATA	51
100 #define GARMIN_PKTID_L001_COMMAND_DATA 10
101 
102 #define CMND_ABORT_TRANSFER 0
103 
104 /* packet ids used in private layer */
105 #define PRIV_PKTID_SET_DEBUG	1
106 #define PRIV_PKTID_SET_MODE	2
107 #define PRIV_PKTID_INFO_REQ	3
108 #define PRIV_PKTID_INFO_RESP	4
109 #define PRIV_PKTID_RESET_REQ	5
110 #define PRIV_PKTID_SET_DEF_MODE	6
111 
112 
113 #define ETX	0x03
114 #define DLE	0x10
115 #define ACK	0x06
116 #define NAK	0x15
117 
118 /* structure used to queue incoming packets */
119 struct garmin_packet {
120 	struct list_head  list;
121 	int               seq;
122 	/* the real size of the data array, always > 0 */
123 	int               size;
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   count;
133 	__u8   pkt_id;
134 	__u32  serial_num;
135 	struct timer_list timer;
136 	struct usb_serial_port *port;
137 	int    seq_counter;
138 	int    insize;
139 	int    outsize;
140 	__u8   inbuffer [GPS_IN_BUFSIZ];  /* tty -> usb */
141 	__u8   outbuffer[GPS_OUT_BUFSIZ]; /* usb -> tty */
142 	__u8   privpkt[4*6];
143 	spinlock_t lock;
144 	struct list_head pktlist;
145 };
146 
147 
148 #define STATE_NEW            0
149 #define STATE_INITIAL_DELAY  1
150 #define STATE_TIMEOUT        2
151 #define STATE_SESSION_REQ1   3
152 #define STATE_SESSION_REQ2   4
153 #define STATE_ACTIVE         5
154 
155 #define STATE_RESET	     8
156 #define STATE_DISCONNECTED   9
157 #define STATE_WAIT_TTY_ACK  10
158 #define STATE_GSP_WAIT_DATA 11
159 
160 #define MODE_NATIVE          0
161 #define MODE_GARMIN_SERIAL   1
162 
163 /* Flags used in garmin_data.flags: */
164 #define FLAGS_SESSION_REPLY_MASK  0x00C0
165 #define FLAGS_SESSION_REPLY1_SEEN 0x0080
166 #define FLAGS_SESSION_REPLY2_SEEN 0x0040
167 #define FLAGS_BULK_IN_ACTIVE      0x0020
168 #define FLAGS_BULK_IN_RESTART     0x0010
169 #define FLAGS_THROTTLED           0x0008
170 #define APP_REQ_SEEN              0x0004
171 #define APP_RESP_SEEN             0x0002
172 #define CLEAR_HALT_REQUIRED       0x0001
173 
174 #define FLAGS_QUEUING             0x0100
175 #define FLAGS_DROP_DATA           0x0800
176 
177 #define FLAGS_GSP_SKIP            0x1000
178 #define FLAGS_GSP_DLESEEN         0x2000
179 
180 
181 
182 
183 
184 
185 /* function prototypes */
186 static int gsp_next_packet(struct garmin_data *garmin_data_p);
187 static int garmin_write_bulk(struct usb_serial_port *port,
188 			     const unsigned char *buf, int count,
189 			     int dismiss_ack);
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_REPLY[]
195 	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
196 static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
197 	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
198 static unsigned char const GARMIN_APP_LAYER_REPLY[]
199 	= { 0x14, 0, 0, 0 };
200 static unsigned char const GARMIN_START_PVT_REQ[]
201 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
202 static unsigned char const GARMIN_STOP_PVT_REQ[]
203 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
204 static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
205 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
206 static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
207 	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
208 static unsigned char const PRIVATE_REQ[]
209 	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };
210 
211 
212 
213 static struct usb_device_id id_table [] = {
214 	/* the same device id seems to be used by all
215 	   usb enabled GPS devices */
216 	{ USB_DEVICE(GARMIN_VENDOR_ID, 3) },
217 	{ }					/* Terminating entry */
218 };
219 
220 MODULE_DEVICE_TABLE(usb, id_table);
221 
222 static struct usb_driver garmin_driver = {
223 	.name =		"garmin_gps",
224 	.probe =	usb_serial_probe,
225 	.disconnect =	usb_serial_disconnect,
226 	.id_table =	id_table,
227 	.no_dynamic_id = 1,
228 };
229 
230 
231 static inline int getLayerId(const __u8 *usbPacket)
232 {
233 	return __le32_to_cpup((__le32 *)(usbPacket));
234 }
235 
236 static inline int getPacketId(const __u8 *usbPacket)
237 {
238 	return __le32_to_cpup((__le32 *)(usbPacket+4));
239 }
240 
241 static inline int getDataLength(const __u8 *usbPacket)
242 {
243 	return __le32_to_cpup((__le32 *)(usbPacket+8));
244 }
245 
246 
247 /*
248  * check if the usb-packet in buf contains an abort-transfer command.
249  * (if yes, all queued data will be dropped)
250  */
251 static inline int isAbortTrfCmnd(const unsigned char *buf)
252 {
253 	if (0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ,
254 					sizeof(GARMIN_STOP_TRANSFER_REQ)) ||
255 	    0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2,
256 					sizeof(GARMIN_STOP_TRANSFER_REQ_V2)))
257 		return 1;
258 	else
259 		return 0;
260 }
261 
262 
263 
264 static void send_to_tty(struct usb_serial_port *port,
265 			char *data, unsigned int actual_length)
266 {
267 	struct tty_struct *tty = tty_port_tty_get(&port->port);
268 
269 	if (tty && actual_length) {
270 
271 		usb_serial_debug_data(debug, &port->dev,
272 					__func__, actual_length, data);
273 
274 		tty_buffer_request_room(tty, actual_length);
275 		tty_insert_flip_string(tty, data, actual_length);
276 		tty_flip_buffer_push(tty);
277 	}
278 	tty_kref_put(tty);
279 }
280 
281 
282 /******************************************************************************
283  * packet queue handling
284  ******************************************************************************/
285 
286 /*
287  * queue a received (usb-)packet for later processing
288  */
289 static int pkt_add(struct garmin_data *garmin_data_p,
290 		   unsigned char *data, unsigned int data_length)
291 {
292 	int state = 0;
293 	int result = 0;
294 	unsigned long flags;
295 	struct garmin_packet *pkt;
296 
297 	/* process only packets containg data ... */
298 	if (data_length) {
299 		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
300 								GFP_ATOMIC);
301 		if (pkt == NULL) {
302 			dev_err(&garmin_data_p->port->dev, "out of memory\n");
303 			return 0;
304 		}
305 		pkt->size = data_length;
306 		memcpy(pkt->data, data, data_length);
307 
308 		spin_lock_irqsave(&garmin_data_p->lock, flags);
309 		garmin_data_p->flags |= FLAGS_QUEUING;
310 		result = list_empty(&garmin_data_p->pktlist);
311 		pkt->seq = garmin_data_p->seq_counter++;
312 		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
313 		state = garmin_data_p->state;
314 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
315 
316 		dbg("%s - added: pkt: %d - %d bytes",
317 			__func__, pkt->seq, data_length);
318 
319 		/* in serial mode, if someone is waiting for data from
320 		   the device, convert and send the next packet to tty. */
321 		if (result && (state == STATE_GSP_WAIT_DATA))
322 			gsp_next_packet(garmin_data_p);
323 	}
324 	return result;
325 }
326 
327 
328 /* get the next pending packet */
329 static struct garmin_packet *pkt_pop(struct garmin_data *garmin_data_p)
330 {
331 	unsigned long flags;
332 	struct garmin_packet *result = NULL;
333 
334 	spin_lock_irqsave(&garmin_data_p->lock, flags);
335 	if (!list_empty(&garmin_data_p->pktlist)) {
336 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
337 		list_del(&result->list);
338 	}
339 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
340 	return result;
341 }
342 
343 
344 /* free up all queued data */
345 static void pkt_clear(struct garmin_data *garmin_data_p)
346 {
347 	unsigned long flags;
348 	struct garmin_packet *result = NULL;
349 
350 	dbg("%s", __func__);
351 
352 	spin_lock_irqsave(&garmin_data_p->lock, flags);
353 	while (!list_empty(&garmin_data_p->pktlist)) {
354 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
355 		list_del(&result->list);
356 		kfree(result);
357 	}
358 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
359 }
360 
361 
362 /******************************************************************************
363  * garmin serial protocol handling handling
364  ******************************************************************************/
365 
366 /* send an ack packet back to the tty */
367 static int gsp_send_ack(struct garmin_data *garmin_data_p, __u8 pkt_id)
368 {
369 	__u8 pkt[10];
370 	__u8 cksum = 0;
371 	__u8 *ptr = pkt;
372 	unsigned  l = 0;
373 
374 	dbg("%s - pkt-id: 0x%X.", __func__, 0xFF & pkt_id);
375 
376 	*ptr++ = DLE;
377 	*ptr++ = ACK;
378 	cksum += ACK;
379 
380 	*ptr++ = 2;
381 	cksum += 2;
382 
383 	*ptr++ = pkt_id;
384 	cksum += pkt_id;
385 
386 	if (pkt_id == DLE)
387 		*ptr++ = DLE;
388 
389 	*ptr++ = 0;
390 	*ptr++ = 0xFF & (-cksum);
391 	*ptr++ = DLE;
392 	*ptr++ = ETX;
393 
394 	l = ptr-pkt;
395 
396 	send_to_tty(garmin_data_p->port, pkt, l);
397 	return 0;
398 }
399 
400 
401 
402 /*
403  * called for a complete packet received from tty layer
404  *
405  * the complete packet (pktid ... cksum) is in garmin_data_p->inbuf starting
406  * at GSP_INITIAL_OFFSET.
407  *
408  * count - number of bytes in the input buffer including space reserved for
409  *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet
410  *         (including pkt-id, data-length a. cksum)
411  */
412 static int gsp_rec_packet(struct garmin_data *garmin_data_p, int count)
413 {
414 	const __u8 *recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
415 	__le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;
416 
417 	int cksum = 0;
418 	int n = 0;
419 	int pktid = recpkt[0];
420 	int size = recpkt[1];
421 
422 	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
423 			       __func__, count-GSP_INITIAL_OFFSET, recpkt);
424 
425 	if (size != (count-GSP_INITIAL_OFFSET-3)) {
426 		dbg("%s - invalid size, expected %d bytes, got %d",
427 			__func__, size, (count-GSP_INITIAL_OFFSET-3));
428 		return -EINVPKT;
429 	}
430 
431 	cksum += *recpkt++;
432 	cksum += *recpkt++;
433 
434 	/* sanity check, remove after test ... */
435 	if ((__u8 *)&(usbdata[3]) != recpkt) {
436 		dbg("%s - ptr mismatch %p - %p",
437 			__func__, &(usbdata[4]), recpkt);
438 		return -EINVPKT;
439 	}
440 
441 	while (n < size) {
442 		cksum += *recpkt++;
443 		n++;
444 	}
445 
446 	if ((0xff & (cksum + *recpkt)) != 0) {
447 		dbg("%s - invalid checksum, expected %02x, got %02x",
448 			__func__, 0xff & -cksum, 0xff & *recpkt);
449 		return -EINVPKT;
450 	}
451 
452 	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
453 	usbdata[1] = __cpu_to_le32(pktid);
454 	usbdata[2] = __cpu_to_le32(size);
455 
456 	garmin_write_bulk(garmin_data_p->port, garmin_data_p->inbuffer,
457 			   GARMIN_PKTHDR_LENGTH+size, 0);
458 
459 	/* if this was an abort-transfer command, flush all
460 	   queued data. */
461 	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
462 		garmin_data_p->flags |= FLAGS_DROP_DATA;
463 		pkt_clear(garmin_data_p);
464 	}
465 
466 	return count;
467 }
468 
469 
470 
471 /*
472  * Called for data received from tty
473  *
474  * buf contains the data read, it may span more than one packet or even
475  * incomplete packets
476  *
477  * input record should be a serial-record, but it may not be complete.
478  * Copy it into our local buffer, until an etx is seen (or an error
479  * occurs).
480  * Once the record is complete, convert into a usb packet and send it
481  * to the bulk pipe, send an ack back to the tty.
482  *
483  * If the input is an ack, just send the last queued packet to the
484  * tty layer.
485  *
486  * if the input is an abort command, drop all queued data.
487  */
488 
489 static int gsp_receive(struct garmin_data *garmin_data_p,
490 		       const unsigned char *buf, int count)
491 {
492 	unsigned long flags;
493 	int offs = 0;
494 	int ack_or_nak_seen = 0;
495 	__u8 *dest;
496 	int size;
497 	/* dleSeen: set if last byte read was a DLE */
498 	int dleSeen;
499 	/* skip: if set, skip incoming data until possible start of
500 	 *       new packet
501 	 */
502 	int skip;
503 	__u8 data;
504 
505 	spin_lock_irqsave(&garmin_data_p->lock, flags);
506 	dest = garmin_data_p->inbuffer;
507 	size = garmin_data_p->insize;
508 	dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
509 	skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
510 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
511 
512 	/* dbg("%s - dle=%d skip=%d size=%d count=%d",
513 		__func__, dleSeen, skip, size, count); */
514 
515 	if (size == 0)
516 		size = GSP_INITIAL_OFFSET;
517 
518 	while (offs < count) {
519 
520 		data = *(buf+offs);
521 		offs++;
522 
523 		if (data == DLE) {
524 			if (skip) { /* start of a new pkt */
525 				skip = 0;
526 				size = GSP_INITIAL_OFFSET;
527 				dleSeen = 1;
528 			} else if (dleSeen) {
529 				dest[size++] = data;
530 				dleSeen = 0;
531 			} else {
532 				dleSeen = 1;
533 			}
534 		} else if (data == ETX) {
535 			if (dleSeen) {
536 				/* packet complete */
537 
538 				data = dest[GSP_INITIAL_OFFSET];
539 
540 				if (data == ACK) {
541 					ack_or_nak_seen = ACK;
542 					dbg("ACK packet complete.");
543 				} else if (data == NAK) {
544 					ack_or_nak_seen = NAK;
545 					dbg("NAK packet complete.");
546 				} else {
547 					dbg("packet complete - id=0x%X.",
548 						0xFF & data);
549 					gsp_rec_packet(garmin_data_p, size);
550 				}
551 
552 				skip = 1;
553 				size = GSP_INITIAL_OFFSET;
554 				dleSeen = 0;
555 			} else {
556 				dest[size++] = data;
557 			}
558 		} else if (!skip) {
559 
560 			if (dleSeen) {
561 				size = GSP_INITIAL_OFFSET;
562 				dleSeen = 0;
563 			}
564 
565 			dest[size++] = data;
566 		}
567 
568 		if (size >= GPS_IN_BUFSIZ) {
569 			dbg("%s - packet too large.", __func__);
570 			skip = 1;
571 			size = GSP_INITIAL_OFFSET;
572 			dleSeen = 0;
573 		}
574 	}
575 
576 	spin_lock_irqsave(&garmin_data_p->lock, flags);
577 
578 	garmin_data_p->insize = size;
579 
580 	/* copy flags back to structure */
581 	if (skip)
582 		garmin_data_p->flags |= FLAGS_GSP_SKIP;
583 	else
584 		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;
585 
586 	if (dleSeen)
587 		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
588 	else
589 		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;
590 
591 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
592 
593 	if (ack_or_nak_seen) {
594 		if (gsp_next_packet(garmin_data_p) > 0)
595 			garmin_data_p->state = STATE_ACTIVE;
596 		else
597 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
598 	}
599 	return count;
600 }
601 
602 
603 
604 /*
605  * Sends a usb packet to the tty
606  *
607  * Assumes, that all packages and at an usb-packet boundary.
608  *
609  * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
610  */
611 static int gsp_send(struct garmin_data *garmin_data_p,
612 		    const unsigned char *buf, int count)
613 {
614 	const unsigned char *src;
615 	unsigned char *dst;
616 	int pktid = 0;
617 	int datalen = 0;
618 	int cksum = 0;
619 	int i = 0;
620 	int k;
621 
622 	dbg("%s - state %d - %d bytes.", __func__,
623 					garmin_data_p->state, count);
624 
625 	k = garmin_data_p->outsize;
626 	if ((k+count) > GPS_OUT_BUFSIZ) {
627 		dbg("packet too large");
628 		garmin_data_p->outsize = 0;
629 		return -4;
630 	}
631 
632 	memcpy(garmin_data_p->outbuffer+k, buf, count);
633 	k += count;
634 	garmin_data_p->outsize = k;
635 
636 	if (k >= GARMIN_PKTHDR_LENGTH) {
637 		pktid  = getPacketId(garmin_data_p->outbuffer);
638 		datalen = getDataLength(garmin_data_p->outbuffer);
639 		i = GARMIN_PKTHDR_LENGTH + datalen;
640 		if (k < i)
641 			return 0;
642 	} else {
643 		return 0;
644 	}
645 
646 	dbg("%s - %d bytes in buffer, %d bytes in pkt.", __func__, k, i);
647 
648 	/* garmin_data_p->outbuffer now contains a complete packet */
649 
650 	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
651 				__func__, k, garmin_data_p->outbuffer);
652 
653 	garmin_data_p->outsize = 0;
654 
655 	if (GARMIN_LAYERID_APPL != getLayerId(garmin_data_p->outbuffer)) {
656 		dbg("not an application packet (%d)",
657 				getLayerId(garmin_data_p->outbuffer));
658 		return -1;
659 	}
660 
661 	if (pktid > 255) {
662 		dbg("packet-id %d too large", pktid);
663 		return -2;
664 	}
665 
666 	if (datalen > 255) {
667 		dbg("packet-size %d too large", datalen);
668 		return -3;
669 	}
670 
671 	/* the serial protocol should be able to handle this packet */
672 
673 	k = 0;
674 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
675 	for (i = 0; i < datalen; i++) {
676 		if (*src++ == DLE)
677 			k++;
678 	}
679 
680 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
681 	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
682 		/* can't add stuffing DLEs in place, move data to end
683 		   of buffer ... */
684 		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
685 		memcpy(dst, src, datalen);
686 		src = dst;
687 	}
688 
689 	dst = garmin_data_p->outbuffer;
690 
691 	*dst++ = DLE;
692 	*dst++ = pktid;
693 	cksum += pktid;
694 	*dst++ = datalen;
695 	cksum += datalen;
696 	if (datalen == DLE)
697 		*dst++ = DLE;
698 
699 	for (i = 0; i < datalen; i++) {
700 		__u8 c = *src++;
701 		*dst++ = c;
702 		cksum += c;
703 		if (c == DLE)
704 			*dst++ = DLE;
705 	}
706 
707 	cksum = 0xFF & -cksum;
708 	*dst++ = cksum;
709 	if (cksum == DLE)
710 		*dst++ = DLE;
711 	*dst++ = DLE;
712 	*dst++ = ETX;
713 
714 	i = dst-garmin_data_p->outbuffer;
715 
716 	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);
717 
718 	garmin_data_p->pkt_id = pktid;
719 	garmin_data_p->state  = STATE_WAIT_TTY_ACK;
720 
721 	return i;
722 }
723 
724 
725 /*
726  * Process the next pending data packet - if there is one
727  */
728 static int gsp_next_packet(struct garmin_data *garmin_data_p)
729 {
730 	int result = 0;
731 	struct garmin_packet *pkt = NULL;
732 
733 	while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
734 		dbg("%s - next pkt: %d", __func__, pkt->seq);
735 		result = gsp_send(garmin_data_p, pkt->data, pkt->size);
736 		if (result > 0) {
737 			kfree(pkt);
738 			return result;
739 		}
740 		kfree(pkt);
741 	}
742 	return result;
743 }
744 
745 
746 
747 /******************************************************************************
748  * garmin native mode
749  ******************************************************************************/
750 
751 
752 /*
753  * Called for data received from tty
754  *
755  * The input data is expected to be in garmin usb-packet format.
756  *
757  * buf contains the data read, it may span more than one packet
758  * or even incomplete packets
759  */
760 static int nat_receive(struct garmin_data *garmin_data_p,
761 		       const unsigned char *buf, int count)
762 {
763 	unsigned long flags;
764 	__u8 *dest;
765 	int offs = 0;
766 	int result = count;
767 	int len;
768 
769 	while (offs < count) {
770 		/* if buffer contains header, copy rest of data */
771 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
772 			len = GARMIN_PKTHDR_LENGTH
773 			      +getDataLength(garmin_data_p->inbuffer);
774 		else
775 			len = GARMIN_PKTHDR_LENGTH;
776 
777 		if (len >= GPS_IN_BUFSIZ) {
778 			/* seems to be an invalid packet, ignore rest
779 			   of input */
780 			dbg("%s - packet size too large: %d", __func__, len);
781 			garmin_data_p->insize = 0;
782 			count = 0;
783 			result = -EINVPKT;
784 		} else {
785 			len -= garmin_data_p->insize;
786 			if (len > (count-offs))
787 				len = (count-offs);
788 			if (len > 0) {
789 				dest = garmin_data_p->inbuffer
790 						+ garmin_data_p->insize;
791 				memcpy(dest, buf+offs, len);
792 				garmin_data_p->insize += len;
793 				offs += len;
794 			}
795 		}
796 
797 		/* do we have a complete packet ? */
798 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
799 			len = GARMIN_PKTHDR_LENGTH+
800 			   getDataLength(garmin_data_p->inbuffer);
801 			if (garmin_data_p->insize >= len) {
802 				garmin_write_bulk(garmin_data_p->port,
803 						   garmin_data_p->inbuffer,
804 						   len, 0);
805 				garmin_data_p->insize = 0;
806 
807 				/* if this was an abort-transfer command,
808 				   flush all queued data. */
809 				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
810 					spin_lock_irqsave(&garmin_data_p->lock,
811 									flags);
812 					garmin_data_p->flags |= FLAGS_DROP_DATA;
813 					spin_unlock_irqrestore(
814 						&garmin_data_p->lock, flags);
815 					pkt_clear(garmin_data_p);
816 				}
817 			}
818 		}
819 	}
820 	return result;
821 }
822 
823 
824 /******************************************************************************
825  * private packets
826  ******************************************************************************/
827 
828 static void priv_status_resp(struct usb_serial_port *port)
829 {
830 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
831 	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;
832 
833 	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
834 	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
835 	pkt[2] = __cpu_to_le32(12);
836 	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
837 	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
838 	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);
839 
840 	send_to_tty(port, (__u8 *)pkt, 6 * 4);
841 }
842 
843 
844 /******************************************************************************
845  * Garmin specific driver functions
846  ******************************************************************************/
847 
848 static int process_resetdev_request(struct usb_serial_port *port)
849 {
850 	unsigned long flags;
851 	int status;
852 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
853 
854 	spin_lock_irqsave(&garmin_data_p->lock, flags);
855 	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
856 	garmin_data_p->state = STATE_RESET;
857 	garmin_data_p->serial_num = 0;
858 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
859 
860 	usb_kill_urb(port->interrupt_in_urb);
861 	dbg("%s - usb_reset_device", __func__);
862 	status = usb_reset_device(port->serial->dev);
863 	if (status)
864 		dbg("%s - usb_reset_device failed: %d",
865 			__func__, status);
866 	return status;
867 }
868 
869 
870 
871 /*
872  * clear all cached data
873  */
874 static int garmin_clear(struct garmin_data *garmin_data_p)
875 {
876 	unsigned long flags;
877 	int status = 0;
878 
879 	/* flush all queued data */
880 	pkt_clear(garmin_data_p);
881 
882 	spin_lock_irqsave(&garmin_data_p->lock, flags);
883 	garmin_data_p->insize = 0;
884 	garmin_data_p->outsize = 0;
885 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
886 
887 	return status;
888 }
889 
890 
891 static int garmin_init_session(struct usb_serial_port *port)
892 {
893 	struct usb_serial *serial = port->serial;
894 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
895 	int status = 0;
896 	int i = 0;
897 
898 	if (status == 0) {
899 		usb_kill_urb(port->interrupt_in_urb);
900 
901 		dbg("%s - adding interrupt input", __func__);
902 		port->interrupt_in_urb->dev = serial->dev;
903 		status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
904 		if (status)
905 			dev_err(&serial->dev->dev,
906 			  "%s - failed submitting interrupt urb, error %d\n",
907 							__func__, status);
908 	}
909 
910 	/*
911 	 * using the initialization method from gpsbabel. See comments in
912 	 * gpsbabel/jeeps/gpslibusb.c gusb_reset_toggles()
913 	 */
914 	if (status == 0) {
915 		dbg("%s - starting session ...", __func__);
916 		garmin_data_p->state = STATE_ACTIVE;
917 
918 		for (i = 0; i < 3; i++) {
919 			status = garmin_write_bulk(port,
920 					GARMIN_START_SESSION_REQ,
921 					sizeof(GARMIN_START_SESSION_REQ), 0);
922 
923 			if (status < 0)
924 				break;
925 		}
926 
927 		if (status > 0)
928 			status = 0;
929 	}
930 
931 	return status;
932 }
933 
934 
935 
936 static int garmin_open(struct tty_struct *tty, struct usb_serial_port *port)
937 {
938 	unsigned long flags;
939 	int status = 0;
940 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
941 
942 	dbg("%s - port %d", __func__, port->number);
943 
944 	spin_lock_irqsave(&garmin_data_p->lock, flags);
945 	garmin_data_p->mode  = initial_mode;
946 	garmin_data_p->count = 0;
947 	garmin_data_p->flags = 0;
948 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
949 
950 	/* shutdown any bulk reads that might be going on */
951 	usb_kill_urb(port->write_urb);
952 	usb_kill_urb(port->read_urb);
953 
954 	if (garmin_data_p->state == STATE_RESET)
955 		status = garmin_init_session(port);
956 
957 	garmin_data_p->state = STATE_ACTIVE;
958 	return status;
959 }
960 
961 
962 static void garmin_close(struct usb_serial_port *port)
963 {
964 	struct usb_serial *serial = port->serial;
965 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
966 
967 	dbg("%s - port %d - mode=%d state=%d flags=0x%X", __func__,
968 		port->number, garmin_data_p->mode,
969 		garmin_data_p->state, garmin_data_p->flags);
970 
971 	if (!serial)
972 		return;
973 
974 	mutex_lock(&port->serial->disc_mutex);
975 
976 	if (!port->serial->disconnected)
977 		garmin_clear(garmin_data_p);
978 
979 	/* shutdown our urbs */
980 	usb_kill_urb(port->read_urb);
981 	usb_kill_urb(port->write_urb);
982 
983 	/* keep reset state so we know that we must start a new session */
984 	if (garmin_data_p->state != STATE_RESET)
985 		garmin_data_p->state = STATE_DISCONNECTED;
986 
987 	mutex_unlock(&port->serial->disc_mutex);
988 }
989 
990 
991 static void garmin_write_bulk_callback(struct urb *urb)
992 {
993 	struct usb_serial_port *port = urb->context;
994 
995 	if (port) {
996 		struct garmin_data *garmin_data_p =
997 					usb_get_serial_port_data(port);
998 
999 		dbg("%s - port %d", __func__, port->number);
1000 
1001 		if (GARMIN_LAYERID_APPL == getLayerId(urb->transfer_buffer)) {
1002 
1003 			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1004 				gsp_send_ack(garmin_data_p,
1005 					((__u8 *)urb->transfer_buffer)[4]);
1006 			}
1007 		}
1008 		usb_serial_port_softint(port);
1009 	}
1010 
1011 	/* Ignore errors that resulted from garmin_write_bulk with
1012 	   dismiss_ack = 1 */
1013 
1014 	/* free up the transfer buffer, as usb_free_urb() does not do this */
1015 	kfree(urb->transfer_buffer);
1016 }
1017 
1018 
1019 static int garmin_write_bulk(struct usb_serial_port *port,
1020 			      const unsigned char *buf, int count,
1021 			      int dismiss_ack)
1022 {
1023 	unsigned long flags;
1024 	struct usb_serial *serial = port->serial;
1025 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1026 	struct urb *urb;
1027 	unsigned char *buffer;
1028 	int status;
1029 
1030 	dbg("%s - port %d, state %d", __func__, port->number,
1031 		garmin_data_p->state);
1032 
1033 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1034 	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
1035 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1036 
1037 	buffer = kmalloc(count, GFP_ATOMIC);
1038 	if (!buffer) {
1039 		dev_err(&port->dev, "out of memory\n");
1040 		return -ENOMEM;
1041 	}
1042 
1043 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1044 	if (!urb) {
1045 		dev_err(&port->dev, "no more free urbs\n");
1046 		kfree(buffer);
1047 		return -ENOMEM;
1048 	}
1049 
1050 	memcpy(buffer, buf, count);
1051 
1052 	usb_serial_debug_data(debug, &port->dev, __func__, count, buffer);
1053 
1054 	usb_fill_bulk_urb(urb, serial->dev,
1055 				usb_sndbulkpipe(serial->dev,
1056 					port->bulk_out_endpointAddress),
1057 				buffer, count,
1058 				garmin_write_bulk_callback,
1059 				dismiss_ack ? NULL : port);
1060 	urb->transfer_flags |= URB_ZERO_PACKET;
1061 
1062 	if (GARMIN_LAYERID_APPL == getLayerId(buffer)) {
1063 
1064 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1065 		garmin_data_p->flags |= APP_REQ_SEEN;
1066 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1067 
1068 		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
1069 			pkt_clear(garmin_data_p);
1070 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
1071 		}
1072 	}
1073 
1074 	/* send it down the pipe */
1075 	status = usb_submit_urb(urb, GFP_ATOMIC);
1076 	if (status) {
1077 		dev_err(&port->dev,
1078 		   "%s - usb_submit_urb(write bulk) failed with status = %d\n",
1079 				__func__, status);
1080 		count = status;
1081 	}
1082 
1083 	/* we are done with this urb, so let the host driver
1084 	 * really free it when it is finished with it */
1085 	usb_free_urb(urb);
1086 
1087 	return count;
1088 }
1089 
1090 static int garmin_write(struct tty_struct *tty, struct usb_serial_port *port,
1091 					 const unsigned char *buf, int count)
1092 {
1093 	int pktid, pktsiz, len;
1094 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1095 	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;
1096 
1097 	usb_serial_debug_data(debug, &port->dev, __func__, count, buf);
1098 
1099 	if (garmin_data_p->state == STATE_RESET)
1100 		return -EIO;
1101 
1102 	/* check for our private packets */
1103 	if (count >= GARMIN_PKTHDR_LENGTH) {
1104 		len = PRIVPKTSIZ;
1105 		if (count < len)
1106 			len = count;
1107 
1108 		memcpy(garmin_data_p->privpkt, buf, len);
1109 
1110 		pktsiz = getDataLength(garmin_data_p->privpkt);
1111 		pktid  = getPacketId(garmin_data_p->privpkt);
1112 
1113 		if (count == (GARMIN_PKTHDR_LENGTH+pktsiz)
1114 		    && GARMIN_LAYERID_PRIVATE ==
1115 				getLayerId(garmin_data_p->privpkt)) {
1116 
1117 			dbg("%s - processing private request %d",
1118 				__func__, pktid);
1119 
1120 			/* drop all unfinished transfers */
1121 			garmin_clear(garmin_data_p);
1122 
1123 			switch (pktid) {
1124 
1125 			case PRIV_PKTID_SET_DEBUG:
1126 				if (pktsiz != 4)
1127 					return -EINVPKT;
1128 				debug = __le32_to_cpu(privpkt[3]);
1129 				dbg("%s - debug level set to 0x%X",
1130 					__func__, debug);
1131 				break;
1132 
1133 			case PRIV_PKTID_SET_MODE:
1134 				if (pktsiz != 4)
1135 					return -EINVPKT;
1136 				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
1137 				dbg("%s - mode set to %d",
1138 					__func__, garmin_data_p->mode);
1139 				break;
1140 
1141 			case PRIV_PKTID_INFO_REQ:
1142 				priv_status_resp(port);
1143 				break;
1144 
1145 			case PRIV_PKTID_RESET_REQ:
1146 				process_resetdev_request(port);
1147 				break;
1148 
1149 			case PRIV_PKTID_SET_DEF_MODE:
1150 				if (pktsiz != 4)
1151 					return -EINVPKT;
1152 				initial_mode = __le32_to_cpu(privpkt[3]);
1153 				dbg("%s - initial_mode set to %d",
1154 					__func__,
1155 					garmin_data_p->mode);
1156 				break;
1157 			}
1158 			return count;
1159 		}
1160 	}
1161 
1162 	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1163 		return gsp_receive(garmin_data_p, buf, count);
1164 	} else {	/* MODE_NATIVE */
1165 		return nat_receive(garmin_data_p, buf, count);
1166 	}
1167 }
1168 
1169 
1170 static int garmin_write_room(struct tty_struct *tty)
1171 {
1172 	struct usb_serial_port *port = tty->driver_data;
1173 	/*
1174 	 * Report back the bytes currently available in the output buffer.
1175 	 */
1176 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1177 	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
1178 }
1179 
1180 
1181 static void garmin_read_process(struct garmin_data *garmin_data_p,
1182 				 unsigned char *data, unsigned data_length)
1183 {
1184 	unsigned long flags;
1185 
1186 	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
1187 		/* abort-transfer cmd is actice */
1188 		dbg("%s - pkt dropped", __func__);
1189 	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
1190 		garmin_data_p->state != STATE_RESET) {
1191 
1192 		/* if throttling is active or postprecessing is required
1193 		   put the received data in the input queue, otherwise
1194 		   send it directly to the tty port */
1195 		if (garmin_data_p->flags & FLAGS_QUEUING) {
1196 			pkt_add(garmin_data_p, data, data_length);
1197 		} else if (getLayerId(data) == GARMIN_LAYERID_APPL) {
1198 
1199 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1200 			garmin_data_p->flags |= APP_RESP_SEEN;
1201 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1202 
1203 			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1204 				pkt_add(garmin_data_p, data, data_length);
1205 			} else {
1206 				send_to_tty(garmin_data_p->port, data,
1207 						data_length);
1208 			}
1209 		}
1210 		/* ignore system layer packets ... */
1211 	}
1212 }
1213 
1214 
1215 static void garmin_read_bulk_callback(struct urb *urb)
1216 {
1217 	unsigned long flags;
1218 	struct usb_serial_port *port = urb->context;
1219 	struct usb_serial *serial =  port->serial;
1220 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1221 	unsigned char *data = urb->transfer_buffer;
1222 	int status = urb->status;
1223 	int retval;
1224 
1225 	dbg("%s - port %d", __func__, port->number);
1226 
1227 	if (!serial) {
1228 		dbg("%s - bad serial pointer, exiting", __func__);
1229 		return;
1230 	}
1231 
1232 	if (status) {
1233 		dbg("%s - nonzero read bulk status received: %d",
1234 			__func__, status);
1235 		return;
1236 	}
1237 
1238 	usb_serial_debug_data(debug, &port->dev,
1239 				__func__, urb->actual_length, data);
1240 
1241 	garmin_read_process(garmin_data_p, data, urb->actual_length);
1242 
1243 	if (urb->actual_length == 0 &&
1244 			0 != (garmin_data_p->flags & FLAGS_BULK_IN_RESTART)) {
1245 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1246 		garmin_data_p->flags &= ~FLAGS_BULK_IN_RESTART;
1247 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1248 		retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1249 		if (retval)
1250 			dev_err(&port->dev,
1251 				"%s - failed resubmitting read urb, error %d\n",
1252 				__func__, retval);
1253 	} else if (urb->actual_length > 0) {
1254 		/* Continue trying to read until nothing more is received  */
1255 		if (0 == (garmin_data_p->flags & FLAGS_THROTTLED)) {
1256 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1257 			if (retval)
1258 				dev_err(&port->dev,
1259 					"%s - failed resubmitting read urb, "
1260 					"error %d\n", __func__, retval);
1261 		}
1262 	} else {
1263 		dbg("%s - end of bulk data", __func__);
1264 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1265 		garmin_data_p->flags &= ~FLAGS_BULK_IN_ACTIVE;
1266 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1267 	}
1268 	return;
1269 }
1270 
1271 
1272 static void garmin_read_int_callback(struct urb *urb)
1273 {
1274 	unsigned long flags;
1275 	int retval;
1276 	struct usb_serial_port *port = urb->context;
1277 	struct usb_serial *serial = port->serial;
1278 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1279 	unsigned char *data = urb->transfer_buffer;
1280 	int status = urb->status;
1281 
1282 	switch (status) {
1283 	case 0:
1284 		/* success */
1285 		break;
1286 	case -ECONNRESET:
1287 	case -ENOENT:
1288 	case -ESHUTDOWN:
1289 		/* this urb is terminated, clean up */
1290 		dbg("%s - urb shutting down with status: %d",
1291 			__func__, status);
1292 		return;
1293 	default:
1294 		dbg("%s - nonzero urb status received: %d",
1295 			__func__, status);
1296 		return;
1297 	}
1298 
1299 	usb_serial_debug_data(debug, &port->dev, __func__,
1300 				urb->actual_length, urb->transfer_buffer);
1301 
1302 	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
1303 	    0 == memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
1304 				sizeof(GARMIN_BULK_IN_AVAIL_REPLY))) {
1305 
1306 		dbg("%s - bulk data available.", __func__);
1307 
1308 		if (0 == (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1309 
1310 			/* bulk data available */
1311 			usb_fill_bulk_urb(port->read_urb, serial->dev,
1312 					usb_rcvbulkpipe(serial->dev,
1313 						port->bulk_in_endpointAddress),
1314 					port->read_urb->transfer_buffer,
1315 					port->read_urb->transfer_buffer_length,
1316 					garmin_read_bulk_callback, port);
1317 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1318 			if (retval) {
1319 				dev_err(&port->dev,
1320 				 "%s - failed submitting read urb, error %d\n",
1321 							__func__, retval);
1322 			} else {
1323 				spin_lock_irqsave(&garmin_data_p->lock, flags);
1324 				garmin_data_p->flags |= FLAGS_BULK_IN_ACTIVE;
1325 				spin_unlock_irqrestore(&garmin_data_p->lock,
1326 									flags);
1327 			}
1328 		} else {
1329 			/* bulk-in transfer still active */
1330 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1331 			garmin_data_p->flags |= FLAGS_BULK_IN_RESTART;
1332 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1333 		}
1334 
1335 	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
1336 			 && 0 == memcmp(data, GARMIN_START_SESSION_REPLY,
1337 					sizeof(GARMIN_START_SESSION_REPLY))) {
1338 
1339 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1340 		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
1341 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1342 
1343 		/* save the serial number */
1344 		garmin_data_p->serial_num = __le32_to_cpup(
1345 					(__le32 *)(data+GARMIN_PKTHDR_LENGTH));
1346 
1347 		dbg("%s - start-of-session reply seen - serial %u.",
1348 			__func__, garmin_data_p->serial_num);
1349 	}
1350 
1351 	garmin_read_process(garmin_data_p, data, urb->actual_length);
1352 
1353 	port->interrupt_in_urb->dev = port->serial->dev;
1354 	retval = usb_submit_urb(urb, GFP_ATOMIC);
1355 	if (retval)
1356 		dev_err(&urb->dev->dev,
1357 			"%s - Error %d submitting interrupt urb\n",
1358 			__func__, retval);
1359 }
1360 
1361 
1362 /*
1363  * Sends the next queued packt to the tty port (garmin native mode only)
1364  * and then sets a timer to call itself again until all queued data
1365  * is sent.
1366  */
1367 static int garmin_flush_queue(struct garmin_data *garmin_data_p)
1368 {
1369 	unsigned long flags;
1370 	struct garmin_packet *pkt;
1371 
1372 	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1373 		pkt = pkt_pop(garmin_data_p);
1374 		if (pkt != NULL) {
1375 			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
1376 			kfree(pkt);
1377 			mod_timer(&garmin_data_p->timer, (1)+jiffies);
1378 
1379 		} else {
1380 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1381 			garmin_data_p->flags &= ~FLAGS_QUEUING;
1382 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1383 		}
1384 	}
1385 	return 0;
1386 }
1387 
1388 
1389 static void garmin_throttle(struct tty_struct *tty)
1390 {
1391 	struct usb_serial_port *port = tty->driver_data;
1392 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1393 
1394 	dbg("%s - port %d", __func__, port->number);
1395 	/* set flag, data received will be put into a queue
1396 	   for later processing */
1397 	spin_lock_irq(&garmin_data_p->lock);
1398 	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
1399 	spin_unlock_irq(&garmin_data_p->lock);
1400 }
1401 
1402 
1403 static void garmin_unthrottle(struct tty_struct *tty)
1404 {
1405 	struct usb_serial_port *port = tty->driver_data;
1406 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1407 	int status;
1408 
1409 	dbg("%s - port %d", __func__, port->number);
1410 	spin_lock_irq(&garmin_data_p->lock);
1411 	garmin_data_p->flags &= ~FLAGS_THROTTLED;
1412 	spin_unlock_irq(&garmin_data_p->lock);
1413 
1414 	/* in native mode send queued data to tty, in
1415 	   serial mode nothing needs to be done here */
1416 	if (garmin_data_p->mode == MODE_NATIVE)
1417 		garmin_flush_queue(garmin_data_p);
1418 
1419 	if (0 != (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1420 		status = usb_submit_urb(port->read_urb, GFP_KERNEL);
1421 		if (status)
1422 			dev_err(&port->dev,
1423 				"%s - failed resubmitting read urb, error %d\n",
1424 				__func__, status);
1425 	}
1426 }
1427 
1428 /*
1429  * The timer is currently only used to send queued packets to
1430  * the tty in cases where the protocol provides no own handshaking
1431  * to initiate the transfer.
1432  */
1433 static void timeout_handler(unsigned long data)
1434 {
1435 	struct garmin_data *garmin_data_p = (struct garmin_data *) data;
1436 
1437 	/* send the next queued packet to the tty port */
1438 	if (garmin_data_p->mode == MODE_NATIVE)
1439 		if (garmin_data_p->flags & FLAGS_QUEUING)
1440 			garmin_flush_queue(garmin_data_p);
1441 }
1442 
1443 
1444 
1445 static int garmin_attach(struct usb_serial *serial)
1446 {
1447 	int status = 0;
1448 	struct usb_serial_port *port = serial->port[0];
1449 	struct garmin_data *garmin_data_p = NULL;
1450 
1451 	dbg("%s", __func__);
1452 
1453 	garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
1454 	if (garmin_data_p == NULL) {
1455 		dev_err(&port->dev, "%s - Out of memory\n", __func__);
1456 		return -ENOMEM;
1457 	}
1458 	init_timer(&garmin_data_p->timer);
1459 	spin_lock_init(&garmin_data_p->lock);
1460 	INIT_LIST_HEAD(&garmin_data_p->pktlist);
1461 	/* garmin_data_p->timer.expires = jiffies + session_timeout; */
1462 	garmin_data_p->timer.data = (unsigned long)garmin_data_p;
1463 	garmin_data_p->timer.function = timeout_handler;
1464 	garmin_data_p->port = port;
1465 	garmin_data_p->state = 0;
1466 	garmin_data_p->count = 0;
1467 	usb_set_serial_port_data(port, garmin_data_p);
1468 
1469 	status = garmin_init_session(port);
1470 
1471 	return status;
1472 }
1473 
1474 
1475 static void garmin_disconnect(struct usb_serial *serial)
1476 {
1477 	struct usb_serial_port *port = serial->port[0];
1478 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1479 
1480 	dbg("%s", __func__);
1481 
1482 	usb_kill_urb(port->interrupt_in_urb);
1483 	del_timer_sync(&garmin_data_p->timer);
1484 }
1485 
1486 
1487 static void garmin_release(struct usb_serial *serial)
1488 {
1489 	struct usb_serial_port *port = serial->port[0];
1490 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1491 
1492 	dbg("%s", __func__);
1493 
1494 	kfree(garmin_data_p);
1495 }
1496 
1497 
1498 /* All of the device info needed */
1499 static struct usb_serial_driver garmin_device = {
1500 	.driver = {
1501 		.owner       = THIS_MODULE,
1502 		.name        = "garmin_gps",
1503 	},
1504 	.description         = "Garmin GPS usb/tty",
1505 	.usb_driver          = &garmin_driver,
1506 	.id_table            = id_table,
1507 	.num_ports           = 1,
1508 	.open                = garmin_open,
1509 	.close               = garmin_close,
1510 	.throttle            = garmin_throttle,
1511 	.unthrottle          = garmin_unthrottle,
1512 	.attach              = garmin_attach,
1513 	.disconnect          = garmin_disconnect,
1514 	.release             = garmin_release,
1515 	.write               = garmin_write,
1516 	.write_room          = garmin_write_room,
1517 	.write_bulk_callback = garmin_write_bulk_callback,
1518 	.read_bulk_callback  = garmin_read_bulk_callback,
1519 	.read_int_callback   = garmin_read_int_callback,
1520 };
1521 
1522 
1523 
1524 static int __init garmin_init(void)
1525 {
1526 	int retval;
1527 
1528 	retval = usb_serial_register(&garmin_device);
1529 	if (retval)
1530 		goto failed_garmin_register;
1531 	retval = usb_register(&garmin_driver);
1532 	if (retval)
1533 		goto failed_usb_register;
1534 	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
1535 	       DRIVER_DESC "\n");
1536 
1537 	return 0;
1538 failed_usb_register:
1539 	usb_serial_deregister(&garmin_device);
1540 failed_garmin_register:
1541 	return retval;
1542 }
1543 
1544 
1545 static void __exit garmin_exit(void)
1546 {
1547 	usb_deregister(&garmin_driver);
1548 	usb_serial_deregister(&garmin_device);
1549 }
1550 
1551 
1552 
1553 
1554 module_init(garmin_init);
1555 module_exit(garmin_exit);
1556 
1557 MODULE_AUTHOR(DRIVER_AUTHOR);
1558 MODULE_DESCRIPTION(DRIVER_DESC);
1559 MODULE_LICENSE("GPL");
1560 
1561 module_param(debug, bool, S_IWUSR | S_IRUGO);
1562 MODULE_PARM_DESC(debug, "Debug enabled or not");
1563 module_param(initial_mode, int, S_IRUGO);
1564 MODULE_PARM_DESC(initial_mode, "Initial mode");
1565 
1566