xref: /linux/drivers/usb/serial/garmin_gps.c (revision 5026bb07be87ef5892742e6853ae6efa0f41961f)
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 /* debug flag */
45 static bool debug;
46 
47 #define GARMIN_VENDOR_ID             0x091E
48 
49 /*
50  * Version Information
51  */
52 
53 #define VERSION_MAJOR	0
54 #define VERSION_MINOR	36
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 const 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 	.disconnect =	usb_serial_disconnect,
225 	.id_table =	id_table,
226 };
227 
228 
229 static inline int getLayerId(const __u8 *usbPacket)
230 {
231 	return __le32_to_cpup((__le32 *)(usbPacket));
232 }
233 
234 static inline int getPacketId(const __u8 *usbPacket)
235 {
236 	return __le32_to_cpup((__le32 *)(usbPacket+4));
237 }
238 
239 static inline int getDataLength(const __u8 *usbPacket)
240 {
241 	return __le32_to_cpup((__le32 *)(usbPacket+8));
242 }
243 
244 
245 /*
246  * check if the usb-packet in buf contains an abort-transfer command.
247  * (if yes, all queued data will be dropped)
248  */
249 static inline int isAbortTrfCmnd(const unsigned char *buf)
250 {
251 	if (0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ,
252 					sizeof(GARMIN_STOP_TRANSFER_REQ)) ||
253 	    0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2,
254 					sizeof(GARMIN_STOP_TRANSFER_REQ_V2)))
255 		return 1;
256 	else
257 		return 0;
258 }
259 
260 
261 
262 static void send_to_tty(struct usb_serial_port *port,
263 			char *data, unsigned int actual_length)
264 {
265 	struct tty_struct *tty = tty_port_tty_get(&port->port);
266 
267 	if (tty && actual_length) {
268 
269 		usb_serial_debug_data(debug, &port->dev,
270 					__func__, actual_length, data);
271 
272 		tty_insert_flip_string(tty, data, actual_length);
273 		tty_flip_buffer_push(tty);
274 	}
275 	tty_kref_put(tty);
276 }
277 
278 
279 /******************************************************************************
280  * packet queue handling
281  ******************************************************************************/
282 
283 /*
284  * queue a received (usb-)packet for later processing
285  */
286 static int pkt_add(struct garmin_data *garmin_data_p,
287 		   unsigned char *data, unsigned int data_length)
288 {
289 	int state = 0;
290 	int result = 0;
291 	unsigned long flags;
292 	struct garmin_packet *pkt;
293 
294 	/* process only packets containg data ... */
295 	if (data_length) {
296 		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
297 								GFP_ATOMIC);
298 		if (pkt == NULL) {
299 			dev_err(&garmin_data_p->port->dev, "out of memory\n");
300 			return 0;
301 		}
302 		pkt->size = data_length;
303 		memcpy(pkt->data, data, data_length);
304 
305 		spin_lock_irqsave(&garmin_data_p->lock, flags);
306 		garmin_data_p->flags |= FLAGS_QUEUING;
307 		result = list_empty(&garmin_data_p->pktlist);
308 		pkt->seq = garmin_data_p->seq_counter++;
309 		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
310 		state = garmin_data_p->state;
311 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
312 
313 		dbg("%s - added: pkt: %d - %d bytes",
314 			__func__, pkt->seq, data_length);
315 
316 		/* in serial mode, if someone is waiting for data from
317 		   the device, convert and send the next packet to tty. */
318 		if (result && (state == STATE_GSP_WAIT_DATA))
319 			gsp_next_packet(garmin_data_p);
320 	}
321 	return result;
322 }
323 
324 
325 /* get the next pending packet */
326 static struct garmin_packet *pkt_pop(struct garmin_data *garmin_data_p)
327 {
328 	unsigned long flags;
329 	struct garmin_packet *result = NULL;
330 
331 	spin_lock_irqsave(&garmin_data_p->lock, flags);
332 	if (!list_empty(&garmin_data_p->pktlist)) {
333 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
334 		list_del(&result->list);
335 	}
336 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
337 	return result;
338 }
339 
340 
341 /* free up all queued data */
342 static void pkt_clear(struct garmin_data *garmin_data_p)
343 {
344 	unsigned long flags;
345 	struct garmin_packet *result = NULL;
346 
347 	spin_lock_irqsave(&garmin_data_p->lock, flags);
348 	while (!list_empty(&garmin_data_p->pktlist)) {
349 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
350 		list_del(&result->list);
351 		kfree(result);
352 	}
353 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
354 }
355 
356 
357 /******************************************************************************
358  * garmin serial protocol handling handling
359  ******************************************************************************/
360 
361 /* send an ack packet back to the tty */
362 static int gsp_send_ack(struct garmin_data *garmin_data_p, __u8 pkt_id)
363 {
364 	__u8 pkt[10];
365 	__u8 cksum = 0;
366 	__u8 *ptr = pkt;
367 	unsigned  l = 0;
368 
369 	dbg("%s - pkt-id: 0x%X.", __func__, 0xFF & pkt_id);
370 
371 	*ptr++ = DLE;
372 	*ptr++ = ACK;
373 	cksum += ACK;
374 
375 	*ptr++ = 2;
376 	cksum += 2;
377 
378 	*ptr++ = pkt_id;
379 	cksum += pkt_id;
380 
381 	if (pkt_id == DLE)
382 		*ptr++ = DLE;
383 
384 	*ptr++ = 0;
385 	*ptr++ = 0xFF & (-cksum);
386 	*ptr++ = DLE;
387 	*ptr++ = ETX;
388 
389 	l = ptr-pkt;
390 
391 	send_to_tty(garmin_data_p->port, pkt, l);
392 	return 0;
393 }
394 
395 
396 
397 /*
398  * called for a complete packet received from tty layer
399  *
400  * the complete packet (pktid ... cksum) is in garmin_data_p->inbuf starting
401  * at GSP_INITIAL_OFFSET.
402  *
403  * count - number of bytes in the input buffer including space reserved for
404  *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet
405  *         (including pkt-id, data-length a. cksum)
406  */
407 static int gsp_rec_packet(struct garmin_data *garmin_data_p, int count)
408 {
409 	unsigned long flags;
410 	const __u8 *recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
411 	__le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;
412 
413 	int cksum = 0;
414 	int n = 0;
415 	int pktid = recpkt[0];
416 	int size = recpkt[1];
417 
418 	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
419 			       __func__, count-GSP_INITIAL_OFFSET, recpkt);
420 
421 	if (size != (count-GSP_INITIAL_OFFSET-3)) {
422 		dbg("%s - invalid size, expected %d bytes, got %d",
423 			__func__, size, (count-GSP_INITIAL_OFFSET-3));
424 		return -EINVPKT;
425 	}
426 
427 	cksum += *recpkt++;
428 	cksum += *recpkt++;
429 
430 	/* sanity check, remove after test ... */
431 	if ((__u8 *)&(usbdata[3]) != recpkt) {
432 		dbg("%s - ptr mismatch %p - %p",
433 			__func__, &(usbdata[4]), recpkt);
434 		return -EINVPKT;
435 	}
436 
437 	while (n < size) {
438 		cksum += *recpkt++;
439 		n++;
440 	}
441 
442 	if ((0xff & (cksum + *recpkt)) != 0) {
443 		dbg("%s - invalid checksum, expected %02x, got %02x",
444 			__func__, 0xff & -cksum, 0xff & *recpkt);
445 		return -EINVPKT;
446 	}
447 
448 	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
449 	usbdata[1] = __cpu_to_le32(pktid);
450 	usbdata[2] = __cpu_to_le32(size);
451 
452 	garmin_write_bulk(garmin_data_p->port, garmin_data_p->inbuffer,
453 			   GARMIN_PKTHDR_LENGTH+size, 0);
454 
455 	/* if this was an abort-transfer command, flush all
456 	   queued data. */
457 	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
458 		spin_lock_irqsave(&garmin_data_p->lock, flags);
459 		garmin_data_p->flags |= FLAGS_DROP_DATA;
460 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
461 		pkt_clear(garmin_data_p);
462 	}
463 
464 	return count;
465 }
466 
467 
468 
469 /*
470  * Called for data received from tty
471  *
472  * buf contains the data read, it may span more than one packet or even
473  * incomplete packets
474  *
475  * input record should be a serial-record, but it may not be complete.
476  * Copy it into our local buffer, until an etx is seen (or an error
477  * occurs).
478  * Once the record is complete, convert into a usb packet and send it
479  * to the bulk pipe, send an ack back to the tty.
480  *
481  * If the input is an ack, just send the last queued packet to the
482  * tty layer.
483  *
484  * if the input is an abort command, drop all queued data.
485  */
486 
487 static int gsp_receive(struct garmin_data *garmin_data_p,
488 		       const unsigned char *buf, int count)
489 {
490 	unsigned long flags;
491 	int offs = 0;
492 	int ack_or_nak_seen = 0;
493 	__u8 *dest;
494 	int size;
495 	/* dleSeen: set if last byte read was a DLE */
496 	int dleSeen;
497 	/* skip: if set, skip incoming data until possible start of
498 	 *       new packet
499 	 */
500 	int skip;
501 	__u8 data;
502 
503 	spin_lock_irqsave(&garmin_data_p->lock, flags);
504 	dest = garmin_data_p->inbuffer;
505 	size = garmin_data_p->insize;
506 	dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
507 	skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
508 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
509 
510 	/* dbg("%s - dle=%d skip=%d size=%d count=%d",
511 		__func__, dleSeen, skip, size, count); */
512 
513 	if (size == 0)
514 		size = GSP_INITIAL_OFFSET;
515 
516 	while (offs < count) {
517 
518 		data = *(buf+offs);
519 		offs++;
520 
521 		if (data == DLE) {
522 			if (skip) { /* start of a new pkt */
523 				skip = 0;
524 				size = GSP_INITIAL_OFFSET;
525 				dleSeen = 1;
526 			} else if (dleSeen) {
527 				dest[size++] = data;
528 				dleSeen = 0;
529 			} else {
530 				dleSeen = 1;
531 			}
532 		} else if (data == ETX) {
533 			if (dleSeen) {
534 				/* packet complete */
535 
536 				data = dest[GSP_INITIAL_OFFSET];
537 
538 				if (data == ACK) {
539 					ack_or_nak_seen = ACK;
540 					dbg("ACK packet complete.");
541 				} else if (data == NAK) {
542 					ack_or_nak_seen = NAK;
543 					dbg("NAK packet complete.");
544 				} else {
545 					dbg("packet complete - id=0x%X.",
546 						0xFF & data);
547 					gsp_rec_packet(garmin_data_p, size);
548 				}
549 
550 				skip = 1;
551 				size = GSP_INITIAL_OFFSET;
552 				dleSeen = 0;
553 			} else {
554 				dest[size++] = data;
555 			}
556 		} else if (!skip) {
557 
558 			if (dleSeen) {
559 				size = GSP_INITIAL_OFFSET;
560 				dleSeen = 0;
561 			}
562 
563 			dest[size++] = data;
564 		}
565 
566 		if (size >= GPS_IN_BUFSIZ) {
567 			dbg("%s - packet too large.", __func__);
568 			skip = 1;
569 			size = GSP_INITIAL_OFFSET;
570 			dleSeen = 0;
571 		}
572 	}
573 
574 	spin_lock_irqsave(&garmin_data_p->lock, flags);
575 
576 	garmin_data_p->insize = size;
577 
578 	/* copy flags back to structure */
579 	if (skip)
580 		garmin_data_p->flags |= FLAGS_GSP_SKIP;
581 	else
582 		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;
583 
584 	if (dleSeen)
585 		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
586 	else
587 		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;
588 
589 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
590 
591 	if (ack_or_nak_seen) {
592 		if (gsp_next_packet(garmin_data_p) > 0)
593 			garmin_data_p->state = STATE_ACTIVE;
594 		else
595 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
596 	}
597 	return count;
598 }
599 
600 
601 
602 /*
603  * Sends a usb packet to the tty
604  *
605  * Assumes, that all packages and at an usb-packet boundary.
606  *
607  * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
608  */
609 static int gsp_send(struct garmin_data *garmin_data_p,
610 		    const unsigned char *buf, int count)
611 {
612 	const unsigned char *src;
613 	unsigned char *dst;
614 	int pktid = 0;
615 	int datalen = 0;
616 	int cksum = 0;
617 	int i = 0;
618 	int k;
619 
620 	dbg("%s - state %d - %d bytes.", __func__,
621 					garmin_data_p->state, count);
622 
623 	k = garmin_data_p->outsize;
624 	if ((k+count) > GPS_OUT_BUFSIZ) {
625 		dbg("packet too large");
626 		garmin_data_p->outsize = 0;
627 		return -4;
628 	}
629 
630 	memcpy(garmin_data_p->outbuffer+k, buf, count);
631 	k += count;
632 	garmin_data_p->outsize = k;
633 
634 	if (k >= GARMIN_PKTHDR_LENGTH) {
635 		pktid  = getPacketId(garmin_data_p->outbuffer);
636 		datalen = getDataLength(garmin_data_p->outbuffer);
637 		i = GARMIN_PKTHDR_LENGTH + datalen;
638 		if (k < i)
639 			return 0;
640 	} else {
641 		return 0;
642 	}
643 
644 	dbg("%s - %d bytes in buffer, %d bytes in pkt.", __func__, k, i);
645 
646 	/* garmin_data_p->outbuffer now contains a complete packet */
647 
648 	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
649 				__func__, k, garmin_data_p->outbuffer);
650 
651 	garmin_data_p->outsize = 0;
652 
653 	if (GARMIN_LAYERID_APPL != getLayerId(garmin_data_p->outbuffer)) {
654 		dbg("not an application packet (%d)",
655 				getLayerId(garmin_data_p->outbuffer));
656 		return -1;
657 	}
658 
659 	if (pktid > 255) {
660 		dbg("packet-id %d too large", pktid);
661 		return -2;
662 	}
663 
664 	if (datalen > 255) {
665 		dbg("packet-size %d too large", datalen);
666 		return -3;
667 	}
668 
669 	/* the serial protocol should be able to handle this packet */
670 
671 	k = 0;
672 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
673 	for (i = 0; i < datalen; i++) {
674 		if (*src++ == DLE)
675 			k++;
676 	}
677 
678 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
679 	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
680 		/* can't add stuffing DLEs in place, move data to end
681 		   of buffer ... */
682 		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
683 		memcpy(dst, src, datalen);
684 		src = dst;
685 	}
686 
687 	dst = garmin_data_p->outbuffer;
688 
689 	*dst++ = DLE;
690 	*dst++ = pktid;
691 	cksum += pktid;
692 	*dst++ = datalen;
693 	cksum += datalen;
694 	if (datalen == DLE)
695 		*dst++ = DLE;
696 
697 	for (i = 0; i < datalen; i++) {
698 		__u8 c = *src++;
699 		*dst++ = c;
700 		cksum += c;
701 		if (c == DLE)
702 			*dst++ = DLE;
703 	}
704 
705 	cksum = 0xFF & -cksum;
706 	*dst++ = cksum;
707 	if (cksum == DLE)
708 		*dst++ = DLE;
709 	*dst++ = DLE;
710 	*dst++ = ETX;
711 
712 	i = dst-garmin_data_p->outbuffer;
713 
714 	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);
715 
716 	garmin_data_p->pkt_id = pktid;
717 	garmin_data_p->state  = STATE_WAIT_TTY_ACK;
718 
719 	return i;
720 }
721 
722 
723 /*
724  * Process the next pending data packet - if there is one
725  */
726 static int gsp_next_packet(struct garmin_data *garmin_data_p)
727 {
728 	int result = 0;
729 	struct garmin_packet *pkt = NULL;
730 
731 	while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
732 		dbg("%s - next pkt: %d", __func__, pkt->seq);
733 		result = gsp_send(garmin_data_p, pkt->data, pkt->size);
734 		if (result > 0) {
735 			kfree(pkt);
736 			return result;
737 		}
738 		kfree(pkt);
739 	}
740 	return result;
741 }
742 
743 
744 
745 /******************************************************************************
746  * garmin native mode
747  ******************************************************************************/
748 
749 
750 /*
751  * Called for data received from tty
752  *
753  * The input data is expected to be in garmin usb-packet format.
754  *
755  * buf contains the data read, it may span more than one packet
756  * or even incomplete packets
757  */
758 static int nat_receive(struct garmin_data *garmin_data_p,
759 		       const unsigned char *buf, int count)
760 {
761 	unsigned long flags;
762 	__u8 *dest;
763 	int offs = 0;
764 	int result = count;
765 	int len;
766 
767 	while (offs < count) {
768 		/* if buffer contains header, copy rest of data */
769 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
770 			len = GARMIN_PKTHDR_LENGTH
771 			      +getDataLength(garmin_data_p->inbuffer);
772 		else
773 			len = GARMIN_PKTHDR_LENGTH;
774 
775 		if (len >= GPS_IN_BUFSIZ) {
776 			/* seems to be an invalid packet, ignore rest
777 			   of input */
778 			dbg("%s - packet size too large: %d", __func__, len);
779 			garmin_data_p->insize = 0;
780 			count = 0;
781 			result = -EINVPKT;
782 		} else {
783 			len -= garmin_data_p->insize;
784 			if (len > (count-offs))
785 				len = (count-offs);
786 			if (len > 0) {
787 				dest = garmin_data_p->inbuffer
788 						+ garmin_data_p->insize;
789 				memcpy(dest, buf+offs, len);
790 				garmin_data_p->insize += len;
791 				offs += len;
792 			}
793 		}
794 
795 		/* do we have a complete packet ? */
796 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
797 			len = GARMIN_PKTHDR_LENGTH+
798 			   getDataLength(garmin_data_p->inbuffer);
799 			if (garmin_data_p->insize >= len) {
800 				garmin_write_bulk(garmin_data_p->port,
801 						   garmin_data_p->inbuffer,
802 						   len, 0);
803 				garmin_data_p->insize = 0;
804 
805 				/* if this was an abort-transfer command,
806 				   flush all queued data. */
807 				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
808 					spin_lock_irqsave(&garmin_data_p->lock,
809 									flags);
810 					garmin_data_p->flags |= FLAGS_DROP_DATA;
811 					spin_unlock_irqrestore(
812 						&garmin_data_p->lock, flags);
813 					pkt_clear(garmin_data_p);
814 				}
815 			}
816 		}
817 	}
818 	return result;
819 }
820 
821 
822 /******************************************************************************
823  * private packets
824  ******************************************************************************/
825 
826 static void priv_status_resp(struct usb_serial_port *port)
827 {
828 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
829 	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;
830 
831 	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
832 	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
833 	pkt[2] = __cpu_to_le32(12);
834 	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
835 	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
836 	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);
837 
838 	send_to_tty(port, (__u8 *)pkt, 6 * 4);
839 }
840 
841 
842 /******************************************************************************
843  * Garmin specific driver functions
844  ******************************************************************************/
845 
846 static int process_resetdev_request(struct usb_serial_port *port)
847 {
848 	unsigned long flags;
849 	int status;
850 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
851 
852 	spin_lock_irqsave(&garmin_data_p->lock, flags);
853 	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
854 	garmin_data_p->state = STATE_RESET;
855 	garmin_data_p->serial_num = 0;
856 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
857 
858 	usb_kill_urb(port->interrupt_in_urb);
859 	dbg("%s - usb_reset_device", __func__);
860 	status = usb_reset_device(port->serial->dev);
861 	if (status)
862 		dbg("%s - usb_reset_device failed: %d",
863 			__func__, status);
864 	return status;
865 }
866 
867 
868 
869 /*
870  * clear all cached data
871  */
872 static int garmin_clear(struct garmin_data *garmin_data_p)
873 {
874 	unsigned long flags;
875 	int status = 0;
876 
877 	/* flush all queued data */
878 	pkt_clear(garmin_data_p);
879 
880 	spin_lock_irqsave(&garmin_data_p->lock, flags);
881 	garmin_data_p->insize = 0;
882 	garmin_data_p->outsize = 0;
883 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
884 
885 	return status;
886 }
887 
888 
889 static int garmin_init_session(struct usb_serial_port *port)
890 {
891 	struct usb_serial *serial = port->serial;
892 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
893 	int status = 0;
894 	int i = 0;
895 
896 	if (status == 0) {
897 		usb_kill_urb(port->interrupt_in_urb);
898 
899 		dbg("%s - adding interrupt input", __func__);
900 		status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
901 		if (status)
902 			dev_err(&serial->dev->dev,
903 			  "%s - failed submitting interrupt urb, error %d\n",
904 							__func__, status);
905 	}
906 
907 	/*
908 	 * using the initialization method from gpsbabel. See comments in
909 	 * gpsbabel/jeeps/gpslibusb.c gusb_reset_toggles()
910 	 */
911 	if (status == 0) {
912 		dbg("%s - starting session ...", __func__);
913 		garmin_data_p->state = STATE_ACTIVE;
914 
915 		for (i = 0; i < 3; i++) {
916 			status = garmin_write_bulk(port,
917 					GARMIN_START_SESSION_REQ,
918 					sizeof(GARMIN_START_SESSION_REQ), 0);
919 
920 			if (status < 0)
921 				break;
922 		}
923 
924 		if (status > 0)
925 			status = 0;
926 	}
927 
928 	return status;
929 }
930 
931 
932 
933 static int garmin_open(struct tty_struct *tty, struct usb_serial_port *port)
934 {
935 	unsigned long flags;
936 	int status = 0;
937 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
938 
939 	spin_lock_irqsave(&garmin_data_p->lock, flags);
940 	garmin_data_p->mode  = initial_mode;
941 	garmin_data_p->count = 0;
942 	garmin_data_p->flags &= FLAGS_SESSION_REPLY1_SEEN;
943 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
944 
945 	/* shutdown any bulk reads that might be going on */
946 	usb_kill_urb(port->write_urb);
947 	usb_kill_urb(port->read_urb);
948 
949 	if (garmin_data_p->state == STATE_RESET)
950 		status = garmin_init_session(port);
951 
952 	garmin_data_p->state = STATE_ACTIVE;
953 	return status;
954 }
955 
956 
957 static void garmin_close(struct usb_serial_port *port)
958 {
959 	struct usb_serial *serial = port->serial;
960 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
961 
962 	dbg("%s - port %d - mode=%d state=%d flags=0x%X", __func__,
963 		port->number, garmin_data_p->mode,
964 		garmin_data_p->state, garmin_data_p->flags);
965 
966 	if (!serial)
967 		return;
968 
969 	mutex_lock(&port->serial->disc_mutex);
970 
971 	if (!port->serial->disconnected)
972 		garmin_clear(garmin_data_p);
973 
974 	/* shutdown our urbs */
975 	usb_kill_urb(port->read_urb);
976 	usb_kill_urb(port->write_urb);
977 
978 	/* keep reset state so we know that we must start a new session */
979 	if (garmin_data_p->state != STATE_RESET)
980 		garmin_data_p->state = STATE_DISCONNECTED;
981 
982 	mutex_unlock(&port->serial->disc_mutex);
983 }
984 
985 
986 static void garmin_write_bulk_callback(struct urb *urb)
987 {
988 	struct usb_serial_port *port = urb->context;
989 
990 	if (port) {
991 		struct garmin_data *garmin_data_p =
992 					usb_get_serial_port_data(port);
993 
994 		if (GARMIN_LAYERID_APPL == getLayerId(urb->transfer_buffer)) {
995 
996 			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
997 				gsp_send_ack(garmin_data_p,
998 					((__u8 *)urb->transfer_buffer)[4]);
999 			}
1000 		}
1001 		usb_serial_port_softint(port);
1002 	}
1003 
1004 	/* Ignore errors that resulted from garmin_write_bulk with
1005 	   dismiss_ack = 1 */
1006 
1007 	/* free up the transfer buffer, as usb_free_urb() does not do this */
1008 	kfree(urb->transfer_buffer);
1009 }
1010 
1011 
1012 static int garmin_write_bulk(struct usb_serial_port *port,
1013 			      const unsigned char *buf, int count,
1014 			      int dismiss_ack)
1015 {
1016 	unsigned long flags;
1017 	struct usb_serial *serial = port->serial;
1018 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1019 	struct urb *urb;
1020 	unsigned char *buffer;
1021 	int status;
1022 
1023 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1024 	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
1025 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1026 
1027 	buffer = kmalloc(count, GFP_ATOMIC);
1028 	if (!buffer) {
1029 		dev_err(&port->dev, "out of memory\n");
1030 		return -ENOMEM;
1031 	}
1032 
1033 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1034 	if (!urb) {
1035 		dev_err(&port->dev, "no more free urbs\n");
1036 		kfree(buffer);
1037 		return -ENOMEM;
1038 	}
1039 
1040 	memcpy(buffer, buf, count);
1041 
1042 	usb_serial_debug_data(debug, &port->dev, __func__, count, buffer);
1043 
1044 	usb_fill_bulk_urb(urb, serial->dev,
1045 				usb_sndbulkpipe(serial->dev,
1046 					port->bulk_out_endpointAddress),
1047 				buffer, count,
1048 				garmin_write_bulk_callback,
1049 				dismiss_ack ? NULL : port);
1050 	urb->transfer_flags |= URB_ZERO_PACKET;
1051 
1052 	if (GARMIN_LAYERID_APPL == getLayerId(buffer)) {
1053 
1054 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1055 		garmin_data_p->flags |= APP_REQ_SEEN;
1056 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1057 
1058 		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
1059 			pkt_clear(garmin_data_p);
1060 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
1061 		}
1062 	}
1063 
1064 	/* send it down the pipe */
1065 	status = usb_submit_urb(urb, GFP_ATOMIC);
1066 	if (status) {
1067 		dev_err(&port->dev,
1068 		   "%s - usb_submit_urb(write bulk) failed with status = %d\n",
1069 				__func__, status);
1070 		count = status;
1071 	}
1072 
1073 	/* we are done with this urb, so let the host driver
1074 	 * really free it when it is finished with it */
1075 	usb_free_urb(urb);
1076 
1077 	return count;
1078 }
1079 
1080 static int garmin_write(struct tty_struct *tty, struct usb_serial_port *port,
1081 					 const unsigned char *buf, int count)
1082 {
1083 	int pktid, pktsiz, len;
1084 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1085 	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;
1086 
1087 	usb_serial_debug_data(debug, &port->dev, __func__, count, buf);
1088 
1089 	if (garmin_data_p->state == STATE_RESET)
1090 		return -EIO;
1091 
1092 	/* check for our private packets */
1093 	if (count >= GARMIN_PKTHDR_LENGTH) {
1094 		len = PRIVPKTSIZ;
1095 		if (count < len)
1096 			len = count;
1097 
1098 		memcpy(garmin_data_p->privpkt, buf, len);
1099 
1100 		pktsiz = getDataLength(garmin_data_p->privpkt);
1101 		pktid  = getPacketId(garmin_data_p->privpkt);
1102 
1103 		if (count == (GARMIN_PKTHDR_LENGTH+pktsiz)
1104 		    && GARMIN_LAYERID_PRIVATE ==
1105 				getLayerId(garmin_data_p->privpkt)) {
1106 
1107 			dbg("%s - processing private request %d",
1108 				__func__, pktid);
1109 
1110 			/* drop all unfinished transfers */
1111 			garmin_clear(garmin_data_p);
1112 
1113 			switch (pktid) {
1114 
1115 			case PRIV_PKTID_SET_DEBUG:
1116 				if (pktsiz != 4)
1117 					return -EINVPKT;
1118 				debug = __le32_to_cpu(privpkt[3]);
1119 				dbg("%s - debug level set to 0x%X",
1120 					__func__, debug);
1121 				break;
1122 
1123 			case PRIV_PKTID_SET_MODE:
1124 				if (pktsiz != 4)
1125 					return -EINVPKT;
1126 				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
1127 				dbg("%s - mode set to %d",
1128 					__func__, garmin_data_p->mode);
1129 				break;
1130 
1131 			case PRIV_PKTID_INFO_REQ:
1132 				priv_status_resp(port);
1133 				break;
1134 
1135 			case PRIV_PKTID_RESET_REQ:
1136 				process_resetdev_request(port);
1137 				break;
1138 
1139 			case PRIV_PKTID_SET_DEF_MODE:
1140 				if (pktsiz != 4)
1141 					return -EINVPKT;
1142 				initial_mode = __le32_to_cpu(privpkt[3]);
1143 				dbg("%s - initial_mode set to %d",
1144 					__func__,
1145 					garmin_data_p->mode);
1146 				break;
1147 			}
1148 			return count;
1149 		}
1150 	}
1151 
1152 	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1153 		return gsp_receive(garmin_data_p, buf, count);
1154 	} else {	/* MODE_NATIVE */
1155 		return nat_receive(garmin_data_p, buf, count);
1156 	}
1157 }
1158 
1159 
1160 static int garmin_write_room(struct tty_struct *tty)
1161 {
1162 	struct usb_serial_port *port = tty->driver_data;
1163 	/*
1164 	 * Report back the bytes currently available in the output buffer.
1165 	 */
1166 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1167 	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
1168 }
1169 
1170 
1171 static void garmin_read_process(struct garmin_data *garmin_data_p,
1172 				 unsigned char *data, unsigned data_length,
1173 				 int bulk_data)
1174 {
1175 	unsigned long flags;
1176 
1177 	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
1178 		/* abort-transfer cmd is actice */
1179 		dbg("%s - pkt dropped", __func__);
1180 	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
1181 		garmin_data_p->state != STATE_RESET) {
1182 
1183 		/* if throttling is active or postprecessing is required
1184 		   put the received data in the input queue, otherwise
1185 		   send it directly to the tty port */
1186 		if (garmin_data_p->flags & FLAGS_QUEUING) {
1187 			pkt_add(garmin_data_p, data, data_length);
1188 		} else if (bulk_data ||
1189 			   getLayerId(data) == GARMIN_LAYERID_APPL) {
1190 
1191 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1192 			garmin_data_p->flags |= APP_RESP_SEEN;
1193 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1194 
1195 			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1196 				pkt_add(garmin_data_p, data, data_length);
1197 			} else {
1198 				send_to_tty(garmin_data_p->port, data,
1199 						data_length);
1200 			}
1201 		}
1202 		/* ignore system layer packets ... */
1203 	}
1204 }
1205 
1206 
1207 static void garmin_read_bulk_callback(struct urb *urb)
1208 {
1209 	unsigned long flags;
1210 	struct usb_serial_port *port = urb->context;
1211 	struct usb_serial *serial =  port->serial;
1212 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1213 	unsigned char *data = urb->transfer_buffer;
1214 	int status = urb->status;
1215 	int retval;
1216 
1217 	if (!serial) {
1218 		dbg("%s - bad serial pointer, exiting", __func__);
1219 		return;
1220 	}
1221 
1222 	if (status) {
1223 		dbg("%s - nonzero read bulk status received: %d",
1224 			__func__, status);
1225 		return;
1226 	}
1227 
1228 	usb_serial_debug_data(debug, &port->dev,
1229 				__func__, urb->actual_length, data);
1230 
1231 	garmin_read_process(garmin_data_p, data, urb->actual_length, 1);
1232 
1233 	if (urb->actual_length == 0 &&
1234 			0 != (garmin_data_p->flags & FLAGS_BULK_IN_RESTART)) {
1235 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1236 		garmin_data_p->flags &= ~FLAGS_BULK_IN_RESTART;
1237 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1238 		retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1239 		if (retval)
1240 			dev_err(&port->dev,
1241 				"%s - failed resubmitting read urb, error %d\n",
1242 				__func__, retval);
1243 	} else if (urb->actual_length > 0) {
1244 		/* Continue trying to read until nothing more is received  */
1245 		if (0 == (garmin_data_p->flags & FLAGS_THROTTLED)) {
1246 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1247 			if (retval)
1248 				dev_err(&port->dev,
1249 					"%s - failed resubmitting read urb, "
1250 					"error %d\n", __func__, retval);
1251 		}
1252 	} else {
1253 		dbg("%s - end of bulk data", __func__);
1254 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1255 		garmin_data_p->flags &= ~FLAGS_BULK_IN_ACTIVE;
1256 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1257 	}
1258 }
1259 
1260 
1261 static void garmin_read_int_callback(struct urb *urb)
1262 {
1263 	unsigned long flags;
1264 	int retval;
1265 	struct usb_serial_port *port = urb->context;
1266 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1267 	unsigned char *data = urb->transfer_buffer;
1268 	int status = urb->status;
1269 
1270 	switch (status) {
1271 	case 0:
1272 		/* success */
1273 		break;
1274 	case -ECONNRESET:
1275 	case -ENOENT:
1276 	case -ESHUTDOWN:
1277 		/* this urb is terminated, clean up */
1278 		dbg("%s - urb shutting down with status: %d",
1279 			__func__, status);
1280 		return;
1281 	default:
1282 		dbg("%s - nonzero urb status received: %d",
1283 			__func__, status);
1284 		return;
1285 	}
1286 
1287 	usb_serial_debug_data(debug, &port->dev, __func__,
1288 				urb->actual_length, urb->transfer_buffer);
1289 
1290 	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
1291 	    0 == memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
1292 				sizeof(GARMIN_BULK_IN_AVAIL_REPLY))) {
1293 
1294 		dbg("%s - bulk data available.", __func__);
1295 
1296 		if (0 == (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1297 
1298 			/* bulk data available */
1299 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1300 			if (retval) {
1301 				dev_err(&port->dev,
1302 				 "%s - failed submitting read urb, error %d\n",
1303 							__func__, retval);
1304 			} else {
1305 				spin_lock_irqsave(&garmin_data_p->lock, flags);
1306 				garmin_data_p->flags |= FLAGS_BULK_IN_ACTIVE;
1307 				spin_unlock_irqrestore(&garmin_data_p->lock,
1308 									flags);
1309 			}
1310 		} else {
1311 			/* bulk-in transfer still active */
1312 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1313 			garmin_data_p->flags |= FLAGS_BULK_IN_RESTART;
1314 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1315 		}
1316 
1317 	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
1318 			 && 0 == memcmp(data, GARMIN_START_SESSION_REPLY,
1319 					sizeof(GARMIN_START_SESSION_REPLY))) {
1320 
1321 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1322 		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
1323 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1324 
1325 		/* save the serial number */
1326 		garmin_data_p->serial_num = __le32_to_cpup(
1327 					(__le32 *)(data+GARMIN_PKTHDR_LENGTH));
1328 
1329 		dbg("%s - start-of-session reply seen - serial %u.",
1330 			__func__, garmin_data_p->serial_num);
1331 	}
1332 
1333 	garmin_read_process(garmin_data_p, data, urb->actual_length, 0);
1334 
1335 	retval = usb_submit_urb(urb, GFP_ATOMIC);
1336 	if (retval)
1337 		dev_err(&urb->dev->dev,
1338 			"%s - Error %d submitting interrupt urb\n",
1339 			__func__, retval);
1340 }
1341 
1342 
1343 /*
1344  * Sends the next queued packt to the tty port (garmin native mode only)
1345  * and then sets a timer to call itself again until all queued data
1346  * is sent.
1347  */
1348 static int garmin_flush_queue(struct garmin_data *garmin_data_p)
1349 {
1350 	unsigned long flags;
1351 	struct garmin_packet *pkt;
1352 
1353 	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1354 		pkt = pkt_pop(garmin_data_p);
1355 		if (pkt != NULL) {
1356 			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
1357 			kfree(pkt);
1358 			mod_timer(&garmin_data_p->timer, (1)+jiffies);
1359 
1360 		} else {
1361 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1362 			garmin_data_p->flags &= ~FLAGS_QUEUING;
1363 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1364 		}
1365 	}
1366 	return 0;
1367 }
1368 
1369 
1370 static void garmin_throttle(struct tty_struct *tty)
1371 {
1372 	struct usb_serial_port *port = tty->driver_data;
1373 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1374 
1375 	/* set flag, data received will be put into a queue
1376 	   for later processing */
1377 	spin_lock_irq(&garmin_data_p->lock);
1378 	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
1379 	spin_unlock_irq(&garmin_data_p->lock);
1380 }
1381 
1382 
1383 static void garmin_unthrottle(struct tty_struct *tty)
1384 {
1385 	struct usb_serial_port *port = tty->driver_data;
1386 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1387 	int status;
1388 
1389 	spin_lock_irq(&garmin_data_p->lock);
1390 	garmin_data_p->flags &= ~FLAGS_THROTTLED;
1391 	spin_unlock_irq(&garmin_data_p->lock);
1392 
1393 	/* in native mode send queued data to tty, in
1394 	   serial mode nothing needs to be done here */
1395 	if (garmin_data_p->mode == MODE_NATIVE)
1396 		garmin_flush_queue(garmin_data_p);
1397 
1398 	if (0 != (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1399 		status = usb_submit_urb(port->read_urb, GFP_KERNEL);
1400 		if (status)
1401 			dev_err(&port->dev,
1402 				"%s - failed resubmitting read urb, error %d\n",
1403 				__func__, status);
1404 	}
1405 }
1406 
1407 /*
1408  * The timer is currently only used to send queued packets to
1409  * the tty in cases where the protocol provides no own handshaking
1410  * to initiate the transfer.
1411  */
1412 static void timeout_handler(unsigned long data)
1413 {
1414 	struct garmin_data *garmin_data_p = (struct garmin_data *) data;
1415 
1416 	/* send the next queued packet to the tty port */
1417 	if (garmin_data_p->mode == MODE_NATIVE)
1418 		if (garmin_data_p->flags & FLAGS_QUEUING)
1419 			garmin_flush_queue(garmin_data_p);
1420 }
1421 
1422 
1423 
1424 static int garmin_attach(struct usb_serial *serial)
1425 {
1426 	int status = 0;
1427 	struct usb_serial_port *port = serial->port[0];
1428 	struct garmin_data *garmin_data_p = NULL;
1429 
1430 	garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
1431 	if (garmin_data_p == NULL) {
1432 		dev_err(&port->dev, "%s - Out of memory\n", __func__);
1433 		return -ENOMEM;
1434 	}
1435 	init_timer(&garmin_data_p->timer);
1436 	spin_lock_init(&garmin_data_p->lock);
1437 	INIT_LIST_HEAD(&garmin_data_p->pktlist);
1438 	/* garmin_data_p->timer.expires = jiffies + session_timeout; */
1439 	garmin_data_p->timer.data = (unsigned long)garmin_data_p;
1440 	garmin_data_p->timer.function = timeout_handler;
1441 	garmin_data_p->port = port;
1442 	garmin_data_p->state = 0;
1443 	garmin_data_p->flags = 0;
1444 	garmin_data_p->count = 0;
1445 	usb_set_serial_port_data(port, garmin_data_p);
1446 
1447 	status = garmin_init_session(port);
1448 
1449 	return status;
1450 }
1451 
1452 
1453 static void garmin_disconnect(struct usb_serial *serial)
1454 {
1455 	struct usb_serial_port *port = serial->port[0];
1456 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1457 
1458 	usb_kill_urb(port->interrupt_in_urb);
1459 	del_timer_sync(&garmin_data_p->timer);
1460 }
1461 
1462 
1463 static void garmin_release(struct usb_serial *serial)
1464 {
1465 	struct usb_serial_port *port = serial->port[0];
1466 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1467 
1468 	kfree(garmin_data_p);
1469 }
1470 
1471 
1472 /* All of the device info needed */
1473 static struct usb_serial_driver garmin_device = {
1474 	.driver = {
1475 		.owner       = THIS_MODULE,
1476 		.name        = "garmin_gps",
1477 	},
1478 	.description         = "Garmin GPS usb/tty",
1479 	.id_table            = id_table,
1480 	.num_ports           = 1,
1481 	.open                = garmin_open,
1482 	.close               = garmin_close,
1483 	.throttle            = garmin_throttle,
1484 	.unthrottle          = garmin_unthrottle,
1485 	.attach              = garmin_attach,
1486 	.disconnect          = garmin_disconnect,
1487 	.release             = garmin_release,
1488 	.write               = garmin_write,
1489 	.write_room          = garmin_write_room,
1490 	.write_bulk_callback = garmin_write_bulk_callback,
1491 	.read_bulk_callback  = garmin_read_bulk_callback,
1492 	.read_int_callback   = garmin_read_int_callback,
1493 };
1494 
1495 static struct usb_serial_driver * const serial_drivers[] = {
1496 	&garmin_device, NULL
1497 };
1498 
1499 module_usb_serial_driver(garmin_driver, serial_drivers);
1500 
1501 MODULE_AUTHOR(DRIVER_AUTHOR);
1502 MODULE_DESCRIPTION(DRIVER_DESC);
1503 MODULE_LICENSE("GPL");
1504 
1505 module_param(debug, bool, S_IWUSR | S_IRUGO);
1506 MODULE_PARM_DESC(debug, "Debug enabled or not");
1507 module_param(initial_mode, int, S_IRUGO);
1508 MODULE_PARM_DESC(initial_mode, "Initial mode");
1509