xref: /linux/drivers/usb/serial/garmin_gps.c (revision 3a20ac2c52b1317f5a5f0bd9cd3cbe8495ddd026)
1 /*
2  * Garmin GPS driver
3  *
4  * Copyright (C) 2006,2007 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	31
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   ignorePkts;
133 	__u8   count;
134 	__u8   pkt_id;
135 	__u32  serial_num;
136 	struct timer_list timer;
137 	struct usb_serial_port *port;
138 	int    seq_counter;
139 	int    insize;
140 	int    outsize;
141 	__u8   inbuffer [GPS_IN_BUFSIZ];  /* tty -> usb */
142 	__u8   outbuffer[GPS_OUT_BUFSIZ]; /* usb -> tty */
143 	__u8   privpkt[4*6];
144 	atomic_t req_count;
145 	atomic_t resp_count;
146 	spinlock_t lock;
147 	struct list_head pktlist;
148 };
149 
150 
151 #define STATE_NEW            0
152 #define STATE_INITIAL_DELAY  1
153 #define STATE_TIMEOUT        2
154 #define STATE_SESSION_REQ1   3
155 #define STATE_SESSION_REQ2   4
156 #define STATE_ACTIVE         5
157 
158 #define STATE_RESET	     8
159 #define STATE_DISCONNECTED   9
160 #define STATE_WAIT_TTY_ACK  10
161 #define STATE_GSP_WAIT_DATA 11
162 
163 #define MODE_NATIVE          0
164 #define MODE_GARMIN_SERIAL   1
165 
166 /* Flags used in garmin_data.flags: */
167 #define FLAGS_SESSION_REPLY_MASK  0x00C0
168 #define FLAGS_SESSION_REPLY1_SEEN 0x0080
169 #define FLAGS_SESSION_REPLY2_SEEN 0x0040
170 #define FLAGS_BULK_IN_ACTIVE      0x0020
171 #define FLAGS_BULK_IN_RESTART     0x0010
172 #define FLAGS_THROTTLED           0x0008
173 #define CLEAR_HALT_REQUIRED       0x0001
174 
175 #define FLAGS_QUEUING             0x0100
176 #define FLAGS_DROP_DATA           0x0800
177 
178 #define FLAGS_GSP_SKIP            0x1000
179 #define FLAGS_GSP_DLESEEN         0x2000
180 
181 
182 
183 
184 
185 
186 /* function prototypes */
187 static void gsp_next_packet(struct garmin_data *garmin_data_p);
188 static int  garmin_write_bulk(struct usb_serial_port *port,
189 			     const unsigned char *buf, int count,
190 			     int dismiss_ack);
191 
192 /* some special packets to be send or received */
193 static unsigned char const GARMIN_START_SESSION_REQ[]
194 	= { 0, 0, 0, 0,  5, 0, 0, 0, 0, 0, 0, 0 };
195 static unsigned char const GARMIN_START_SESSION_REQ2[]
196 	= { 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0 };
197 static unsigned char const GARMIN_START_SESSION_REPLY[]
198 	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
199 static unsigned char const GARMIN_SESSION_ACTIVE_REPLY[]
200 	= { 0, 0, 0, 0, 17, 0, 0, 0, 4, 0, 0, 0, 0, 16, 0, 0 };
201 static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
202 	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
203 static unsigned char const GARMIN_APP_LAYER_REPLY[]
204 	= { 0x14, 0, 0, 0 };
205 static unsigned char const GARMIN_START_PVT_REQ[]
206 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
207 static unsigned char const GARMIN_STOP_PVT_REQ[]
208 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
209 static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
210 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
211 static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
212 	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
213 static unsigned char const PRIVATE_REQ[]
214 	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };
215 
216 
217 
218 static struct usb_device_id id_table [] = {
219 	/* the same device id seems to be used by all
220 	   usb enabled GPS devices */
221 	{ USB_DEVICE(GARMIN_VENDOR_ID, 3) },
222 	{ }					/* Terminating entry */
223 };
224 
225 MODULE_DEVICE_TABLE(usb, id_table);
226 
227 static struct usb_driver garmin_driver = {
228 	.name =		"garmin_gps",
229 	.probe =	usb_serial_probe,
230 	.disconnect =	usb_serial_disconnect,
231 	.id_table =	id_table,
232 	.no_dynamic_id = 1,
233 };
234 
235 
236 static inline int noResponseFromAppLayer(struct garmin_data *garmin_data_p)
237 {
238 	return atomic_read(&garmin_data_p->req_count) ==
239 				atomic_read(&garmin_data_p->resp_count);
240 }
241 
242 
243 static inline int getLayerId(const __u8 *usbPacket)
244 {
245 	return __le32_to_cpup((__le32 *)(usbPacket));
246 }
247 
248 static inline int getPacketId(const __u8 *usbPacket)
249 {
250 	return __le32_to_cpup((__le32 *)(usbPacket+4));
251 }
252 
253 static inline int getDataLength(const __u8 *usbPacket)
254 {
255 	return __le32_to_cpup((__le32 *)(usbPacket+8));
256 }
257 
258 
259 /*
260  * check if the usb-packet in buf contains an abort-transfer command.
261  * (if yes, all queued data will be dropped)
262  */
263 static inline int isAbortTrfCmnd(const unsigned char *buf)
264 {
265 	if (0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ,
266 					sizeof(GARMIN_STOP_TRANSFER_REQ)) ||
267 	    0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2,
268 					sizeof(GARMIN_STOP_TRANSFER_REQ_V2)))
269 		return 1;
270 	else
271 		return 0;
272 }
273 
274 
275 
276 static void send_to_tty(struct usb_serial_port *port,
277 			char *data, unsigned int actual_length)
278 {
279 	struct tty_struct *tty = tty_port_tty_get(&port->port);
280 
281 	if (tty && actual_length) {
282 
283 		usb_serial_debug_data(debug, &port->dev,
284 					__func__, actual_length, data);
285 
286 		tty_buffer_request_room(tty, actual_length);
287 		tty_insert_flip_string(tty, data, actual_length);
288 		tty_flip_buffer_push(tty);
289 	}
290 	tty_kref_put(tty);
291 }
292 
293 
294 /******************************************************************************
295  * packet queue handling
296  ******************************************************************************/
297 
298 /*
299  * queue a received (usb-)packet for later processing
300  */
301 static int pkt_add(struct garmin_data *garmin_data_p,
302 		   unsigned char *data, unsigned int data_length)
303 {
304 	int state = 0;
305 	int result = 0;
306 	unsigned long flags;
307 	struct garmin_packet *pkt;
308 
309 	/* process only packets containg data ... */
310 	if (data_length) {
311 		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
312 								GFP_ATOMIC);
313 		if (pkt == NULL) {
314 			dev_err(&garmin_data_p->port->dev, "out of memory\n");
315 			return 0;
316 		}
317 		pkt->size = data_length;
318 		memcpy(pkt->data, data, data_length);
319 
320 		spin_lock_irqsave(&garmin_data_p->lock, flags);
321 		garmin_data_p->flags |= FLAGS_QUEUING;
322 		result = list_empty(&garmin_data_p->pktlist);
323 		pkt->seq = garmin_data_p->seq_counter++;
324 		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
325 		state = garmin_data_p->state;
326 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
327 
328 		/* in serial mode, if someone is waiting for data from
329 		   the device, iconvert and send the next packet to tty. */
330 		if (result && (state == STATE_GSP_WAIT_DATA))
331 			gsp_next_packet(garmin_data_p);
332 	}
333 	return result;
334 }
335 
336 
337 /* get the next pending packet */
338 static struct garmin_packet *pkt_pop(struct garmin_data *garmin_data_p)
339 {
340 	unsigned long flags;
341 	struct garmin_packet *result = NULL;
342 
343 	spin_lock_irqsave(&garmin_data_p->lock, flags);
344 	if (!list_empty(&garmin_data_p->pktlist)) {
345 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
346 		list_del(&result->list);
347 	}
348 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
349 	return result;
350 }
351 
352 
353 /* free up all queued data */
354 static void pkt_clear(struct garmin_data *garmin_data_p)
355 {
356 	unsigned long flags;
357 	struct garmin_packet *result = NULL;
358 
359 	dbg("%s", __func__);
360 
361 	spin_lock_irqsave(&garmin_data_p->lock, flags);
362 	while (!list_empty(&garmin_data_p->pktlist)) {
363 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
364 		list_del(&result->list);
365 		kfree(result);
366 	}
367 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
368 }
369 
370 
371 /******************************************************************************
372  * garmin serial protocol handling handling
373  ******************************************************************************/
374 
375 /* send an ack packet back to the tty */
376 static int gsp_send_ack(struct garmin_data *garmin_data_p, __u8 pkt_id)
377 {
378 	__u8 pkt[10];
379 	__u8 cksum = 0;
380 	__u8 *ptr = pkt;
381 	unsigned  l = 0;
382 
383 	dbg("%s - pkt-id: 0x%X.", __func__, 0xFF & pkt_id);
384 
385 	*ptr++ = DLE;
386 	*ptr++ = ACK;
387 	cksum += ACK;
388 
389 	*ptr++ = 2;
390 	cksum += 2;
391 
392 	*ptr++ = pkt_id;
393 	cksum += pkt_id;
394 
395 	if (pkt_id == DLE)
396 		*ptr++ = DLE;
397 
398 	*ptr++ = 0;
399 	*ptr++ = 0xFF & (-cksum);
400 	*ptr++ = DLE;
401 	*ptr++ = ETX;
402 
403 	l = ptr-pkt;
404 
405 	send_to_tty(garmin_data_p->port, pkt, l);
406 	return 0;
407 }
408 
409 
410 
411 /*
412  * called for a complete packet received from tty layer
413  *
414  * the complete packet (pkzid ... cksum) is in garmin_data_p->inbuf starting
415  * at GSP_INITIAL_OFFSET.
416  *
417  * count - number of bytes in the input buffer including space reserved for
418  *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet
419  *         (including pkt-id, data-length a. cksum)
420  */
421 static int gsp_rec_packet(struct garmin_data *garmin_data_p, int count)
422 {
423 	const __u8 *recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
424 	__le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;
425 
426 	int cksum = 0;
427 	int n = 0;
428 	int pktid = recpkt[0];
429 	int size = recpkt[1];
430 
431 	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
432 			       __func__, count-GSP_INITIAL_OFFSET, recpkt);
433 
434 	if (size != (count-GSP_INITIAL_OFFSET-3)) {
435 		dbg("%s - invalid size, expected %d bytes, got %d",
436 			__func__, size, (count-GSP_INITIAL_OFFSET-3));
437 		return -EINVPKT;
438 	}
439 
440 	cksum += *recpkt++;
441 	cksum += *recpkt++;
442 
443 	/* sanity check, remove after test ... */
444 	if ((__u8 *)&(usbdata[3]) != recpkt) {
445 		dbg("%s - ptr mismatch %p - %p",
446 			__func__, &(usbdata[4]), recpkt);
447 		return -EINVPKT;
448 	}
449 
450 	while (n < size) {
451 		cksum += *recpkt++;
452 		n++;
453 	}
454 
455 	if ((0xff & (cksum + *recpkt)) != 0) {
456 		dbg("%s - invalid checksum, expected %02x, got %02x",
457 			__func__, 0xff & -cksum, 0xff & *recpkt);
458 		return -EINVPKT;
459 	}
460 
461 	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
462 	usbdata[1] = __cpu_to_le32(pktid);
463 	usbdata[2] = __cpu_to_le32(size);
464 
465 	garmin_write_bulk(garmin_data_p->port, garmin_data_p->inbuffer,
466 			   GARMIN_PKTHDR_LENGTH+size, 0);
467 
468 	/* if this was an abort-transfer command, flush all
469 	   queued data. */
470 	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
471 		garmin_data_p->flags |= FLAGS_DROP_DATA;
472 		pkt_clear(garmin_data_p);
473 	}
474 
475 	return count;
476 }
477 
478 
479 
480 /*
481  * Called for data received from tty
482  *
483  * buf contains the data read, it may span more than one packet or even
484  * incomplete packets
485  *
486  * input record should be a serial-record, but it may not be complete.
487  * Copy it into our local buffer, until an etx is seen (or an error
488  * occurs).
489  * Once the record is complete, convert into a usb packet and send it
490  * to the bulk pipe, send an ack back to the tty.
491  *
492  * If the input is an ack, just send the last queued packet to the
493  * tty layer.
494  *
495  * if the input is an abort command, drop all queued data.
496  */
497 
498 static int gsp_receive(struct garmin_data *garmin_data_p,
499 		       const unsigned char *buf, int count)
500 {
501 	unsigned long flags;
502 	int offs = 0;
503 	int ack_or_nak_seen = 0;
504 	int i = 0;
505 	__u8 *dest;
506 	int size;
507 	/* dleSeen: set if last byte read was a DLE */
508 	int dleSeen;
509 	/* skip: if set, skip incoming data until possible start of
510 	 *       new packet
511 	 */
512 	int skip;
513 	__u8 data;
514 
515 	spin_lock_irqsave(&garmin_data_p->lock, flags);
516 	dest = garmin_data_p->inbuffer;
517 	size = garmin_data_p->insize;
518 	dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
519 	skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
520 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
521 
522 	dbg("%s - dle=%d skip=%d size=%d count=%d",
523 		__func__, dleSeen, skip, size, count);
524 
525 	if (size == 0)
526 		size = GSP_INITIAL_OFFSET;
527 
528 	while (offs < count) {
529 
530 		data = *(buf+offs);
531 		offs++;
532 
533 		if (data == DLE) {
534 			if (skip) { /* start of a new pkt */
535 				skip = 0;
536 				size = GSP_INITIAL_OFFSET;
537 				dleSeen = 1;
538 			} else if (dleSeen) {
539 				dest[size++] = data;
540 				dleSeen = 0;
541 			} else {
542 				dleSeen = 1;
543 			}
544 		} else if (data == ETX) {
545 			if (dleSeen) {
546 				/* packet complete */
547 
548 				data = dest[GSP_INITIAL_OFFSET];
549 
550 				if (data == ACK) {
551 					ack_or_nak_seen = ACK;
552 					dbg("ACK packet complete.");
553 				} else if (data == NAK) {
554 					ack_or_nak_seen = NAK;
555 					dbg("NAK packet complete.");
556 				} else {
557 					dbg("packet complete - id=0x%X.",
558 						0xFF & data);
559 					gsp_rec_packet(garmin_data_p, size);
560 				}
561 
562 				skip = 1;
563 				size = GSP_INITIAL_OFFSET;
564 				dleSeen = 0;
565 			} else {
566 				dest[size++] = data;
567 			}
568 		} else if (!skip) {
569 
570 			if (dleSeen) {
571 				dbg("non-masked DLE at %d - restarting", i);
572 				size = GSP_INITIAL_OFFSET;
573 				dleSeen = 0;
574 			}
575 
576 			dest[size++] = data;
577 		}
578 
579 		if (size >= GPS_IN_BUFSIZ) {
580 			dbg("%s - packet too large.", __func__);
581 			skip = 1;
582 			size = GSP_INITIAL_OFFSET;
583 			dleSeen = 0;
584 		}
585 	}
586 
587 	spin_lock_irqsave(&garmin_data_p->lock, flags);
588 
589 	garmin_data_p->insize = size;
590 
591 	/* copy flags back to structure */
592 	if (skip)
593 		garmin_data_p->flags |= FLAGS_GSP_SKIP;
594 	else
595 		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;
596 
597 	if (dleSeen)
598 		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
599 	else
600 		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;
601 
602 	if (ack_or_nak_seen)
603 		garmin_data_p->state = STATE_GSP_WAIT_DATA;
604 
605 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
606 
607 	if (ack_or_nak_seen)
608 		gsp_next_packet(garmin_data_p);
609 	return count;
610 }
611 
612 
613 
614 
615 /*
616  * Sends a usb packet to the tty
617  *
618  * Assumes, that all packages and at an usb-packet boundary.
619  *
620  * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
621  */
622 static int gsp_send(struct garmin_data *garmin_data_p,
623 		    const unsigned char *buf, int count)
624 {
625 	const unsigned char *src;
626 	unsigned char *dst;
627 	int pktid = 0;
628 	int datalen = 0;
629 	int cksum = 0;
630 	int i = 0;
631 	int k;
632 
633 	dbg("%s - state %d - %d bytes.", __func__,
634 					garmin_data_p->state, count);
635 
636 	k = garmin_data_p->outsize;
637 	if ((k+count) > GPS_OUT_BUFSIZ) {
638 		dbg("packet too large");
639 		garmin_data_p->outsize = 0;
640 		return -4;
641 	}
642 
643 	memcpy(garmin_data_p->outbuffer+k, buf, count);
644 	k += count;
645 	garmin_data_p->outsize = k;
646 
647 	if (k >= GARMIN_PKTHDR_LENGTH) {
648 		pktid  = getPacketId(garmin_data_p->outbuffer);
649 		datalen = getDataLength(garmin_data_p->outbuffer);
650 		i = GARMIN_PKTHDR_LENGTH + datalen;
651 		if (k < i)
652 			return 0;
653 	} else {
654 		return 0;
655 	}
656 
657 	dbg("%s - %d bytes in buffer, %d bytes in pkt.", __func__, k, i);
658 
659 	/* garmin_data_p->outbuffer now contains a complete packet */
660 
661 	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
662 				__func__, k, garmin_data_p->outbuffer);
663 
664 	garmin_data_p->outsize = 0;
665 
666 	if (GARMIN_LAYERID_APPL != getLayerId(garmin_data_p->outbuffer)) {
667 		dbg("not an application packet (%d)",
668 				getLayerId(garmin_data_p->outbuffer));
669 		return -1;
670 	}
671 
672 	if (pktid > 255) {
673 		dbg("packet-id %d too large", pktid);
674 		return -2;
675 	}
676 
677 	if (datalen > 255) {
678 		dbg("packet-size %d too large", datalen);
679 		return -3;
680 	}
681 
682 	/* the serial protocol should be able to handle this packet */
683 
684 	k = 0;
685 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
686 	for (i = 0; i < datalen; i++) {
687 		if (*src++ == DLE)
688 			k++;
689 	}
690 
691 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
692 	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
693 		/* can't add stuffing DLEs in place, move data to end
694 		   of buffer ... */
695 		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
696 		memcpy(dst, src, datalen);
697 		src = dst;
698 	}
699 
700 	dst = garmin_data_p->outbuffer;
701 
702 	*dst++ = DLE;
703 	*dst++ = pktid;
704 	cksum += pktid;
705 	*dst++ = datalen;
706 	cksum += datalen;
707 	if (datalen == DLE)
708 		*dst++ = DLE;
709 
710 	for (i = 0; i < datalen; i++) {
711 		__u8 c = *src++;
712 		*dst++ = c;
713 		cksum += c;
714 		if (c == DLE)
715 			*dst++ = DLE;
716 	}
717 
718 	cksum = 0xFF & -cksum;
719 	*dst++ = cksum;
720 	if (cksum == DLE)
721 		*dst++ = DLE;
722 	*dst++ = DLE;
723 	*dst++ = ETX;
724 
725 	i = dst-garmin_data_p->outbuffer;
726 
727 	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);
728 
729 	garmin_data_p->pkt_id = pktid;
730 	garmin_data_p->state  = STATE_WAIT_TTY_ACK;
731 
732 	return i;
733 }
734 
735 
736 
737 
738 
739 /*
740  * Process the next pending data packet - if there is one
741  */
742 static void gsp_next_packet(struct garmin_data *garmin_data_p)
743 {
744 	struct garmin_packet *pkt = NULL;
745 
746 	while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
747 		dbg("%s - next pkt: %d", __func__, pkt->seq);
748 		if (gsp_send(garmin_data_p, pkt->data, pkt->size) > 0) {
749 			kfree(pkt);
750 			return;
751 		}
752 		kfree(pkt);
753 	}
754 }
755 
756 
757 
758 
759 /******************************************************************************
760  * garmin native mode
761  ******************************************************************************/
762 
763 
764 /*
765  * Called for data received from tty
766  *
767  * The input data is expected to be in garmin usb-packet format.
768  *
769  * buf contains the data read, it may span more than one packet
770  * or even incomplete packets
771  */
772 static int nat_receive(struct garmin_data *garmin_data_p,
773 		       const unsigned char *buf, int count)
774 {
775 	unsigned long flags;
776 	__u8 *dest;
777 	int offs = 0;
778 	int result = count;
779 	int len;
780 
781 	while (offs < count) {
782 		/* if buffer contains header, copy rest of data */
783 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
784 			len = GARMIN_PKTHDR_LENGTH
785 			      +getDataLength(garmin_data_p->inbuffer);
786 		else
787 			len = GARMIN_PKTHDR_LENGTH;
788 
789 		if (len >= GPS_IN_BUFSIZ) {
790 			/* seems to be an invalid packet, ignore rest
791 			   of input */
792 			dbg("%s - packet size too large: %d", __func__, len);
793 			garmin_data_p->insize = 0;
794 			count = 0;
795 			result = -EINVPKT;
796 		} else {
797 			len -= garmin_data_p->insize;
798 			if (len > (count-offs))
799 				len = (count-offs);
800 			if (len > 0) {
801 				dest = garmin_data_p->inbuffer
802 						+ garmin_data_p->insize;
803 				memcpy(dest, buf+offs, len);
804 				garmin_data_p->insize += len;
805 				offs += len;
806 			}
807 		}
808 
809 		/* do we have a complete packet ? */
810 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
811 			len = GARMIN_PKTHDR_LENGTH+
812 			   getDataLength(garmin_data_p->inbuffer);
813 			if (garmin_data_p->insize >= len) {
814 				garmin_write_bulk(garmin_data_p->port,
815 						   garmin_data_p->inbuffer,
816 						   len, 0);
817 				garmin_data_p->insize = 0;
818 
819 				/* if this was an abort-transfer command,
820 				   flush all queued data. */
821 				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
822 					spin_lock_irqsave(&garmin_data_p->lock,
823 									flags);
824 					garmin_data_p->flags |= FLAGS_DROP_DATA;
825 					spin_unlock_irqrestore(
826 						&garmin_data_p->lock, flags);
827 					pkt_clear(garmin_data_p);
828 				}
829 			}
830 		}
831 	}
832 	return result;
833 }
834 
835 
836 /******************************************************************************
837  * private packets
838  ******************************************************************************/
839 
840 static void priv_status_resp(struct usb_serial_port *port)
841 {
842 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
843 	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;
844 
845 	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
846 	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
847 	pkt[2] = __cpu_to_le32(12);
848 	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
849 	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
850 	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);
851 
852 	send_to_tty(port, (__u8 *)pkt, 6 * 4);
853 }
854 
855 
856 /******************************************************************************
857  * Garmin specific driver functions
858  ******************************************************************************/
859 
860 static int process_resetdev_request(struct usb_serial_port *port)
861 {
862 	unsigned long flags;
863 	int status;
864 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
865 
866 	spin_lock_irqsave(&garmin_data_p->lock, flags);
867 	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
868 	garmin_data_p->state = STATE_RESET;
869 	garmin_data_p->serial_num = 0;
870 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
871 
872 	usb_kill_urb(port->interrupt_in_urb);
873 	dbg("%s - usb_reset_device", __func__);
874 	status = usb_reset_device(port->serial->dev);
875 	if (status)
876 		dbg("%s - usb_reset_device failed: %d",
877 			__func__, status);
878 	return status;
879 }
880 
881 
882 
883 /*
884  * clear all cached data
885  */
886 static int garmin_clear(struct garmin_data *garmin_data_p)
887 {
888 	unsigned long flags;
889 	int status = 0;
890 
891 	struct usb_serial_port *port = garmin_data_p->port;
892 
893 	if (port != NULL && atomic_read(&garmin_data_p->resp_count)) {
894 		/* send a terminate command */
895 		status = garmin_write_bulk(port, GARMIN_STOP_TRANSFER_REQ,
896 					sizeof(GARMIN_STOP_TRANSFER_REQ), 1);
897 	}
898 
899 	/* flush all queued data */
900 	pkt_clear(garmin_data_p);
901 
902 	spin_lock_irqsave(&garmin_data_p->lock, flags);
903 	garmin_data_p->insize = 0;
904 	garmin_data_p->outsize = 0;
905 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
906 
907 	return status;
908 }
909 
910 
911 
912 
913 
914 
915 static int garmin_init_session(struct usb_serial_port *port)
916 {
917 	unsigned long flags;
918 	struct usb_serial *serial = port->serial;
919 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
920 	int status = 0;
921 
922 	if (status == 0) {
923 		usb_kill_urb(port->interrupt_in_urb);
924 
925 		dbg("%s - adding interrupt input", __func__);
926 		port->interrupt_in_urb->dev = serial->dev;
927 		status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
928 		if (status)
929 			dev_err(&serial->dev->dev,
930 			  "%s - failed submitting interrupt urb, error %d\n",
931 							__func__, status);
932 	}
933 
934 	if (status == 0) {
935 		dbg("%s - starting session ...", __func__);
936 		garmin_data_p->state = STATE_ACTIVE;
937 		status = garmin_write_bulk(port, GARMIN_START_SESSION_REQ,
938 					sizeof(GARMIN_START_SESSION_REQ), 0);
939 
940 		if (status >= 0) {
941 
942 			spin_lock_irqsave(&garmin_data_p->lock, flags);
943 			garmin_data_p->ignorePkts++;
944 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
945 
946 			/* not needed, but the win32 driver does it too ... */
947 			status = garmin_write_bulk(port,
948 					GARMIN_START_SESSION_REQ2,
949 					sizeof(GARMIN_START_SESSION_REQ2), 0);
950 			if (status >= 0) {
951 				status = 0;
952 				spin_lock_irqsave(&garmin_data_p->lock, flags);
953 				garmin_data_p->ignorePkts++;
954 				spin_unlock_irqrestore(&garmin_data_p->lock,
955 									flags);
956 			}
957 		}
958 	}
959 
960 	return status;
961 }
962 
963 
964 
965 
966 
967 static int garmin_open(struct tty_struct *tty,
968 			struct usb_serial_port *port, struct file *filp)
969 {
970 	unsigned long flags;
971 	int status = 0;
972 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
973 
974 	dbg("%s - port %d", __func__, port->number);
975 
976 	spin_lock_irqsave(&garmin_data_p->lock, flags);
977 	garmin_data_p->mode  = initial_mode;
978 	garmin_data_p->count = 0;
979 	garmin_data_p->flags = 0;
980 	atomic_set(&garmin_data_p->req_count, 0);
981 	atomic_set(&garmin_data_p->resp_count, 0);
982 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
983 
984 	/* shutdown any bulk reads that might be going on */
985 	usb_kill_urb(port->write_urb);
986 	usb_kill_urb(port->read_urb);
987 
988 	if (garmin_data_p->state == STATE_RESET)
989 		status = garmin_init_session(port);
990 
991 	garmin_data_p->state = STATE_ACTIVE;
992 	return status;
993 }
994 
995 
996 static void garmin_close(struct tty_struct *tty,
997 			struct usb_serial_port *port, struct file *filp)
998 {
999 	struct usb_serial *serial = port->serial;
1000 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1001 
1002 	dbg("%s - port %d - mode=%d state=%d flags=0x%X", __func__,
1003 		port->number, garmin_data_p->mode,
1004 		garmin_data_p->state, garmin_data_p->flags);
1005 
1006 	if (!serial)
1007 		return;
1008 
1009 	mutex_lock(&port->serial->disc_mutex);
1010 	if (!port->serial->disconnected)
1011 		garmin_clear(garmin_data_p);
1012 
1013 	/* shutdown our urbs */
1014 	usb_kill_urb(port->read_urb);
1015 	usb_kill_urb(port->write_urb);
1016 
1017 	if (!port->serial->disconnected) {
1018 		if (noResponseFromAppLayer(garmin_data_p) ||
1019 		    ((garmin_data_p->flags & CLEAR_HALT_REQUIRED) != 0)) {
1020 			process_resetdev_request(port);
1021 			garmin_data_p->state = STATE_RESET;
1022 		} else {
1023 			garmin_data_p->state = STATE_DISCONNECTED;
1024 		}
1025 	} else {
1026 		garmin_data_p->state = STATE_DISCONNECTED;
1027 	}
1028 	mutex_unlock(&port->serial->disc_mutex);
1029 }
1030 
1031 static void garmin_write_bulk_callback(struct urb *urb)
1032 {
1033 	unsigned long flags;
1034 	struct usb_serial_port *port = urb->context;
1035 	int status = urb->status;
1036 
1037 	if (port) {
1038 		struct garmin_data *garmin_data_p =
1039 					usb_get_serial_port_data(port);
1040 
1041 		dbg("%s - port %d", __func__, port->number);
1042 
1043 		if (GARMIN_LAYERID_APPL == getLayerId(urb->transfer_buffer)
1044 		    && (garmin_data_p->mode == MODE_GARMIN_SERIAL))  {
1045 			gsp_send_ack(garmin_data_p,
1046 					((__u8 *)urb->transfer_buffer)[4]);
1047 		}
1048 
1049 		if (status) {
1050 			dbg("%s - nonzero write bulk status received: %d",
1051 			    __func__, status);
1052 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1053 			garmin_data_p->flags |= CLEAR_HALT_REQUIRED;
1054 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1055 		}
1056 
1057 		usb_serial_port_softint(port);
1058 	}
1059 
1060 	/* Ignore errors that resulted from garmin_write_bulk with
1061 	   dismiss_ack = 1 */
1062 
1063 	/* free up the transfer buffer, as usb_free_urb() does not do this */
1064 	kfree(urb->transfer_buffer);
1065 }
1066 
1067 
1068 static int garmin_write_bulk(struct usb_serial_port *port,
1069 			      const unsigned char *buf, int count,
1070 			      int dismiss_ack)
1071 {
1072 	unsigned long flags;
1073 	struct usb_serial *serial = port->serial;
1074 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1075 	struct urb *urb;
1076 	unsigned char *buffer;
1077 	int status;
1078 
1079 	dbg("%s - port %d, state %d", __func__, port->number,
1080 		garmin_data_p->state);
1081 
1082 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1083 	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
1084 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1085 
1086 	buffer = kmalloc(count, GFP_ATOMIC);
1087 	if (!buffer) {
1088 		dev_err(&port->dev, "out of memory\n");
1089 		return -ENOMEM;
1090 	}
1091 
1092 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1093 	if (!urb) {
1094 		dev_err(&port->dev, "no more free urbs\n");
1095 		kfree(buffer);
1096 		return -ENOMEM;
1097 	}
1098 
1099 	memcpy(buffer, buf, count);
1100 
1101 	usb_serial_debug_data(debug, &port->dev, __func__, count, buffer);
1102 
1103 	usb_fill_bulk_urb(urb, serial->dev,
1104 				usb_sndbulkpipe(serial->dev,
1105 					port->bulk_out_endpointAddress),
1106 				buffer, count,
1107 				garmin_write_bulk_callback,
1108 				dismiss_ack ? NULL : port);
1109 	urb->transfer_flags |= URB_ZERO_PACKET;
1110 
1111 	if (GARMIN_LAYERID_APPL == getLayerId(buffer)) {
1112 		atomic_inc(&garmin_data_p->req_count);
1113 		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
1114 			pkt_clear(garmin_data_p);
1115 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
1116 		}
1117 	}
1118 
1119 	/* send it down the pipe */
1120 	status = usb_submit_urb(urb, GFP_ATOMIC);
1121 	if (status) {
1122 		dev_err(&port->dev,
1123 		   "%s - usb_submit_urb(write bulk) failed with status = %d\n",
1124 				__func__, status);
1125 		count = status;
1126 	}
1127 
1128 	/* we are done with this urb, so let the host driver
1129 	 * really free it when it is finished with it */
1130 	usb_free_urb(urb);
1131 
1132 	return count;
1133 }
1134 
1135 static int garmin_write(struct tty_struct *tty, struct usb_serial_port *port,
1136 					 const unsigned char *buf, int count)
1137 {
1138 	int pktid, pktsiz, len;
1139 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1140 	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;
1141 
1142 	usb_serial_debug_data(debug, &port->dev, __func__, count, buf);
1143 
1144 	/* check for our private packets */
1145 	if (count >= GARMIN_PKTHDR_LENGTH) {
1146 		len = PRIVPKTSIZ;
1147 		if (count < len)
1148 			len = count;
1149 
1150 		memcpy(garmin_data_p->privpkt, buf, len);
1151 
1152 		pktsiz = getDataLength(garmin_data_p->privpkt);
1153 		pktid  = getPacketId(garmin_data_p->privpkt);
1154 
1155 		if (count == (GARMIN_PKTHDR_LENGTH+pktsiz)
1156 		    && GARMIN_LAYERID_PRIVATE ==
1157 				getLayerId(garmin_data_p->privpkt)) {
1158 
1159 			dbg("%s - processing private request %d",
1160 				__func__, pktid);
1161 
1162 			/* drop all unfinished transfers */
1163 			garmin_clear(garmin_data_p);
1164 
1165 			switch (pktid) {
1166 
1167 			case PRIV_PKTID_SET_DEBUG:
1168 				if (pktsiz != 4)
1169 					return -EINVPKT;
1170 				debug = __le32_to_cpu(privpkt[3]);
1171 				dbg("%s - debug level set to 0x%X",
1172 					__func__, debug);
1173 				break;
1174 
1175 			case PRIV_PKTID_SET_MODE:
1176 				if (pktsiz != 4)
1177 					return -EINVPKT;
1178 				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
1179 				dbg("%s - mode set to %d",
1180 					__func__, garmin_data_p->mode);
1181 				break;
1182 
1183 			case PRIV_PKTID_INFO_REQ:
1184 				priv_status_resp(port);
1185 				break;
1186 
1187 			case PRIV_PKTID_RESET_REQ:
1188 				atomic_inc(&garmin_data_p->req_count);
1189 				break;
1190 
1191 			case PRIV_PKTID_SET_DEF_MODE:
1192 				if (pktsiz != 4)
1193 					return -EINVPKT;
1194 				initial_mode = __le32_to_cpu(privpkt[3]);
1195 				dbg("%s - initial_mode set to %d",
1196 					__func__,
1197 					garmin_data_p->mode);
1198 				break;
1199 			}
1200 			return count;
1201 		}
1202 	}
1203 
1204 	garmin_data_p->ignorePkts = 0;
1205 
1206 	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1207 		return gsp_receive(garmin_data_p, buf, count);
1208 	} else {	/* MODE_NATIVE */
1209 		return nat_receive(garmin_data_p, buf, count);
1210 	}
1211 }
1212 
1213 
1214 static int garmin_write_room(struct tty_struct *tty)
1215 {
1216 	struct usb_serial_port *port = tty->driver_data;
1217 	/*
1218 	 * Report back the bytes currently available in the output buffer.
1219 	 */
1220 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1221 	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
1222 }
1223 
1224 
1225 static void garmin_read_process(struct garmin_data *garmin_data_p,
1226 				 unsigned char *data, unsigned data_length)
1227 {
1228 	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
1229 		/* abort-transfer cmd is actice */
1230 		dbg("%s - pkt dropped", __func__);
1231 	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
1232 		garmin_data_p->state != STATE_RESET) {
1233 
1234 		/* remember any appl.layer packets, so we know
1235 		   if a reset is required or not when closing
1236 		   the device */
1237 		if (0 == memcmp(data, GARMIN_APP_LAYER_REPLY,
1238 				sizeof(GARMIN_APP_LAYER_REPLY))) {
1239 			atomic_inc(&garmin_data_p->resp_count);
1240 		}
1241 
1242 		/* if throttling is active or postprecessing is required
1243 		   put the received data in the input queue, otherwise
1244 		   send it directly to the tty port */
1245 		if (garmin_data_p->flags & FLAGS_QUEUING) {
1246 			pkt_add(garmin_data_p, data, data_length);
1247 		} else if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1248 			if (getLayerId(data) == GARMIN_LAYERID_APPL)
1249 				pkt_add(garmin_data_p, data, data_length);
1250 		} else {
1251 			send_to_tty(garmin_data_p->port, data, data_length);
1252 		}
1253 	}
1254 }
1255 
1256 
1257 static void garmin_read_bulk_callback(struct urb *urb)
1258 {
1259 	unsigned long flags;
1260 	struct usb_serial_port *port = urb->context;
1261 	struct usb_serial *serial =  port->serial;
1262 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1263 	unsigned char *data = urb->transfer_buffer;
1264 	int status = urb->status;
1265 	int retval;
1266 
1267 	dbg("%s - port %d", __func__, port->number);
1268 
1269 	if (!serial) {
1270 		dbg("%s - bad serial pointer, exiting", __func__);
1271 		return;
1272 	}
1273 
1274 	if (status) {
1275 		dbg("%s - nonzero read bulk status received: %d",
1276 			__func__, status);
1277 		return;
1278 	}
1279 
1280 	usb_serial_debug_data(debug, &port->dev,
1281 				__func__, urb->actual_length, data);
1282 
1283 	garmin_read_process(garmin_data_p, data, urb->actual_length);
1284 
1285 	if (urb->actual_length == 0 &&
1286 			0 != (garmin_data_p->flags & FLAGS_BULK_IN_RESTART)) {
1287 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1288 		garmin_data_p->flags &= ~FLAGS_BULK_IN_RESTART;
1289 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1290 		retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1291 		if (retval)
1292 			dev_err(&port->dev,
1293 				"%s - failed resubmitting read urb, error %d\n",
1294 				__func__, retval);
1295 	} else if (urb->actual_length > 0) {
1296 		/* Continue trying to read until nothing more is received  */
1297 		if (0 == (garmin_data_p->flags & FLAGS_THROTTLED)) {
1298 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1299 			if (retval)
1300 				dev_err(&port->dev,
1301 					"%s - failed resubmitting read urb, "
1302 					"error %d\n", __func__, retval);
1303 		}
1304 	} else {
1305 		dbg("%s - end of bulk data", __func__);
1306 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1307 		garmin_data_p->flags &= ~FLAGS_BULK_IN_ACTIVE;
1308 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1309 	}
1310 	return;
1311 }
1312 
1313 
1314 static void garmin_read_int_callback(struct urb *urb)
1315 {
1316 	unsigned long flags;
1317 	int retval;
1318 	struct usb_serial_port *port = urb->context;
1319 	struct usb_serial *serial = port->serial;
1320 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1321 	unsigned char *data = urb->transfer_buffer;
1322 	int status = urb->status;
1323 
1324 	switch (status) {
1325 	case 0:
1326 		/* success */
1327 		break;
1328 	case -ECONNRESET:
1329 	case -ENOENT:
1330 	case -ESHUTDOWN:
1331 		/* this urb is terminated, clean up */
1332 		dbg("%s - urb shutting down with status: %d",
1333 			__func__, status);
1334 		return;
1335 	default:
1336 		dbg("%s - nonzero urb status received: %d",
1337 			__func__, status);
1338 		return;
1339 	}
1340 
1341 	usb_serial_debug_data(debug, &port->dev, __func__,
1342 				urb->actual_length, urb->transfer_buffer);
1343 
1344 	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
1345 	    0 == memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
1346 				sizeof(GARMIN_BULK_IN_AVAIL_REPLY))) {
1347 
1348 		dbg("%s - bulk data available.", __func__);
1349 
1350 		if (0 == (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1351 
1352 			/* bulk data available */
1353 			usb_fill_bulk_urb(port->read_urb, serial->dev,
1354 					usb_rcvbulkpipe(serial->dev,
1355 						port->bulk_in_endpointAddress),
1356 					port->read_urb->transfer_buffer,
1357 					port->read_urb->transfer_buffer_length,
1358 					garmin_read_bulk_callback, port);
1359 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1360 			if (retval) {
1361 				dev_err(&port->dev,
1362 				 "%s - failed submitting read urb, error %d\n",
1363 							__func__, retval);
1364 			} else {
1365 				spin_lock_irqsave(&garmin_data_p->lock, flags);
1366 				garmin_data_p->flags |= FLAGS_BULK_IN_ACTIVE;
1367 				/* do not send this packet to the user */
1368 				garmin_data_p->ignorePkts = 1;
1369 				spin_unlock_irqrestore(&garmin_data_p->lock,
1370 									flags);
1371 			}
1372 		} else {
1373 			/* bulk-in transfer still active */
1374 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1375 			garmin_data_p->flags |= FLAGS_BULK_IN_RESTART;
1376 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1377 		}
1378 
1379 	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
1380 			 && 0 == memcmp(data, GARMIN_START_SESSION_REPLY,
1381 					sizeof(GARMIN_START_SESSION_REPLY))) {
1382 
1383 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1384 		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
1385 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1386 
1387 		/* save the serial number */
1388 		garmin_data_p->serial_num = __le32_to_cpup(
1389 					(__le32 *)(data+GARMIN_PKTHDR_LENGTH));
1390 
1391 		dbg("%s - start-of-session reply seen - serial %u.",
1392 			__func__, garmin_data_p->serial_num);
1393 	}
1394 
1395 	if (garmin_data_p->ignorePkts) {
1396 		/* this reply belongs to a request generated by the driver,
1397 		   ignore it. */
1398 		dbg("%s - pkt ignored (%d)",
1399 			__func__, garmin_data_p->ignorePkts);
1400 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1401 		garmin_data_p->ignorePkts--;
1402 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1403 	} else {
1404 		garmin_read_process(garmin_data_p, data, urb->actual_length);
1405 	}
1406 
1407 	port->interrupt_in_urb->dev = port->serial->dev;
1408 	retval = usb_submit_urb(urb, GFP_ATOMIC);
1409 	if (retval)
1410 		dev_err(&urb->dev->dev,
1411 			"%s - Error %d submitting interrupt urb\n",
1412 			__func__, retval);
1413 }
1414 
1415 
1416 /*
1417  * Sends the next queued packt to the tty port (garmin native mode only)
1418  * and then sets a timer to call itself again until all queued data
1419  * is sent.
1420  */
1421 static int garmin_flush_queue(struct garmin_data *garmin_data_p)
1422 {
1423 	unsigned long flags;
1424 	struct garmin_packet *pkt;
1425 
1426 	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1427 		pkt = pkt_pop(garmin_data_p);
1428 		if (pkt != NULL) {
1429 			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
1430 			kfree(pkt);
1431 			mod_timer(&garmin_data_p->timer, (1)+jiffies);
1432 
1433 		} else {
1434 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1435 			garmin_data_p->flags &= ~FLAGS_QUEUING;
1436 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1437 		}
1438 	}
1439 	return 0;
1440 }
1441 
1442 
1443 static void garmin_throttle(struct tty_struct *tty)
1444 {
1445 	struct usb_serial_port *port = tty->driver_data;
1446 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1447 	unsigned long flags;
1448 
1449 	dbg("%s - port %d", __func__, port->number);
1450 	/* set flag, data received will be put into a queue
1451 	   for later processing */
1452 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1453 	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
1454 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1455 }
1456 
1457 
1458 static void garmin_unthrottle(struct tty_struct *tty)
1459 {
1460 	struct usb_serial_port *port = tty->driver_data;
1461 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1462 	unsigned long flags;
1463 	int status;
1464 
1465 	dbg("%s - port %d", __func__, port->number);
1466 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1467 	garmin_data_p->flags &= ~FLAGS_THROTTLED;
1468 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1469 
1470 	/* in native mode send queued data to tty, in
1471 	   serial mode nothing needs to be done here */
1472 	if (garmin_data_p->mode == MODE_NATIVE)
1473 		garmin_flush_queue(garmin_data_p);
1474 
1475 	if (0 != (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1476 		status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1477 		if (status)
1478 			dev_err(&port->dev,
1479 				"%s - failed resubmitting read urb, error %d\n",
1480 				__func__, status);
1481 	}
1482 }
1483 
1484 /*
1485  * The timer is currently only used to send queued packets to
1486  * the tty in cases where the protocol provides no own handshaking
1487  * to initiate the transfer.
1488  */
1489 static void timeout_handler(unsigned long data)
1490 {
1491 	struct garmin_data *garmin_data_p = (struct garmin_data *) data;
1492 
1493 	/* send the next queued packet to the tty port */
1494 	if (garmin_data_p->mode == MODE_NATIVE)
1495 		if (garmin_data_p->flags & FLAGS_QUEUING)
1496 			garmin_flush_queue(garmin_data_p);
1497 }
1498 
1499 
1500 
1501 static int garmin_attach(struct usb_serial *serial)
1502 {
1503 	int status = 0;
1504 	struct usb_serial_port *port = serial->port[0];
1505 	struct garmin_data *garmin_data_p = NULL;
1506 
1507 	dbg("%s", __func__);
1508 
1509 	garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
1510 	if (garmin_data_p == NULL) {
1511 		dev_err(&port->dev, "%s - Out of memory\n", __func__);
1512 		return -ENOMEM;
1513 	}
1514 	init_timer(&garmin_data_p->timer);
1515 	spin_lock_init(&garmin_data_p->lock);
1516 	INIT_LIST_HEAD(&garmin_data_p->pktlist);
1517 	/* garmin_data_p->timer.expires = jiffies + session_timeout; */
1518 	garmin_data_p->timer.data = (unsigned long)garmin_data_p;
1519 	garmin_data_p->timer.function = timeout_handler;
1520 	garmin_data_p->port = port;
1521 	garmin_data_p->state = 0;
1522 	garmin_data_p->count = 0;
1523 	usb_set_serial_port_data(port, garmin_data_p);
1524 
1525 	status = garmin_init_session(port);
1526 
1527 	return status;
1528 }
1529 
1530 
1531 static void garmin_shutdown(struct usb_serial *serial)
1532 {
1533 	struct usb_serial_port *port = serial->port[0];
1534 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1535 
1536 	dbg("%s", __func__);
1537 
1538 	usb_kill_urb(port->interrupt_in_urb);
1539 	del_timer_sync(&garmin_data_p->timer);
1540 	kfree(garmin_data_p);
1541 	usb_set_serial_port_data(port, NULL);
1542 }
1543 
1544 
1545 /* All of the device info needed */
1546 static struct usb_serial_driver garmin_device = {
1547 	.driver = {
1548 		.owner       = THIS_MODULE,
1549 		.name        = "garmin_gps",
1550 	},
1551 	.description         = "Garmin GPS usb/tty",
1552 	.usb_driver          = &garmin_driver,
1553 	.id_table            = id_table,
1554 	.num_ports           = 1,
1555 	.open                = garmin_open,
1556 	.close               = garmin_close,
1557 	.throttle            = garmin_throttle,
1558 	.unthrottle          = garmin_unthrottle,
1559 	.attach              = garmin_attach,
1560 	.shutdown            = garmin_shutdown,
1561 	.write               = garmin_write,
1562 	.write_room          = garmin_write_room,
1563 	.write_bulk_callback = garmin_write_bulk_callback,
1564 	.read_bulk_callback  = garmin_read_bulk_callback,
1565 	.read_int_callback   = garmin_read_int_callback,
1566 };
1567 
1568 
1569 
1570 static int __init garmin_init(void)
1571 {
1572 	int retval;
1573 
1574 	retval = usb_serial_register(&garmin_device);
1575 	if (retval)
1576 		goto failed_garmin_register;
1577 	retval = usb_register(&garmin_driver);
1578 	if (retval)
1579 		goto failed_usb_register;
1580 	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
1581 	       DRIVER_DESC "\n");
1582 
1583 	return 0;
1584 failed_usb_register:
1585 	usb_serial_deregister(&garmin_device);
1586 failed_garmin_register:
1587 	return retval;
1588 }
1589 
1590 
1591 static void __exit garmin_exit(void)
1592 {
1593 	usb_deregister(&garmin_driver);
1594 	usb_serial_deregister(&garmin_device);
1595 }
1596 
1597 
1598 
1599 
1600 module_init(garmin_init);
1601 module_exit(garmin_exit);
1602 
1603 MODULE_AUTHOR(DRIVER_AUTHOR);
1604 MODULE_DESCRIPTION(DRIVER_DESC);
1605 MODULE_LICENSE("GPL");
1606 
1607 module_param(debug, bool, S_IWUSR | S_IRUGO);
1608 MODULE_PARM_DESC(debug, "Debug enabled or not");
1609 module_param(initial_mode, int, S_IRUGO);
1610 MODULE_PARM_DESC(initial_mode, "Initial mode");
1611 
1612