xref: /linux/drivers/usb/serial/garmin_gps.c (revision c1a357b68614620c976a94260749a979f9c46d29)
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/slab.h>
29 #include <linux/timer.h>
30 #include <linux/tty.h>
31 #include <linux/tty_driver.h>
32 #include <linux/tty_flip.h>
33 #include <linux/module.h>
34 #include <linux/spinlock.h>
35 #include <linux/uaccess.h>
36 #include <linux/atomic.h>
37 #include <linux/usb.h>
38 #include <linux/usb/serial.h>
39 
40 /* the mode to be set when the port ist opened */
41 static int initial_mode = 1;
42 
43 #define GARMIN_VENDOR_ID             0x091E
44 
45 /*
46  * Version Information
47  */
48 
49 #define VERSION_MAJOR	0
50 #define VERSION_MINOR	36
51 
52 #define _STR(s) #s
53 #define _DRIVER_VERSION(a, b) "v" _STR(a) "." _STR(b)
54 #define DRIVER_VERSION _DRIVER_VERSION(VERSION_MAJOR, VERSION_MINOR)
55 #define DRIVER_AUTHOR "hermann kneissel"
56 #define DRIVER_DESC "garmin gps driver"
57 
58 /* error codes returned by the driver */
59 #define EINVPKT	1000	/* invalid packet structure */
60 
61 
62 /* size of the header of a packet using the usb protocol */
63 #define GARMIN_PKTHDR_LENGTH	12
64 
65 /* max. possible size of a packet using the serial protocol */
66 #define MAX_SERIAL_PKT_SIZ (3 + 255 + 3)
67 
68 /*  max. possible size of a packet with worst case stuffing */
69 #define MAX_SERIAL_PKT_SIZ_STUFFED (MAX_SERIAL_PKT_SIZ + 256)
70 
71 /* size of a buffer able to hold a complete (no stuffing) packet
72  * (the document protocol does not contain packets with a larger
73  *  size, but in theory a packet may be 64k+12 bytes - if in
74  *  later protocol versions larger packet sizes occur, this value
75  *  should be increased accordingly, so the input buffer is always
76  *  large enough the store a complete packet inclusive header) */
77 #define GPS_IN_BUFSIZ  (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ)
78 
79 /* size of a buffer able to hold a complete (incl. stuffing) packet */
80 #define GPS_OUT_BUFSIZ (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ_STUFFED)
81 
82 /* where to place the packet id of a serial packet, so we can
83  * prepend the usb-packet header without the need to move the
84  * packets data */
85 #define GSP_INITIAL_OFFSET (GARMIN_PKTHDR_LENGTH-2)
86 
87 /* max. size of incoming private packets (header+1 param) */
88 #define PRIVPKTSIZ (GARMIN_PKTHDR_LENGTH+4)
89 
90 #define GARMIN_LAYERID_TRANSPORT  0
91 #define GARMIN_LAYERID_APPL      20
92 /* our own layer-id to use for some control mechanisms */
93 #define GARMIN_LAYERID_PRIVATE	0x01106E4B
94 
95 #define GARMIN_PKTID_PVT_DATA	51
96 #define GARMIN_PKTID_L001_COMMAND_DATA 10
97 
98 #define CMND_ABORT_TRANSFER 0
99 
100 /* packet ids used in private layer */
101 #define PRIV_PKTID_SET_DEBUG	1
102 #define PRIV_PKTID_SET_MODE	2
103 #define PRIV_PKTID_INFO_REQ	3
104 #define PRIV_PKTID_INFO_RESP	4
105 #define PRIV_PKTID_RESET_REQ	5
106 #define PRIV_PKTID_SET_DEF_MODE	6
107 
108 
109 #define ETX	0x03
110 #define DLE	0x10
111 #define ACK	0x06
112 #define NAK	0x15
113 
114 /* structure used to queue incoming packets */
115 struct garmin_packet {
116 	struct list_head  list;
117 	int               seq;
118 	/* the real size of the data array, always > 0 */
119 	int               size;
120 	__u8              data[1];
121 };
122 
123 /* structure used to keep the current state of the driver */
124 struct garmin_data {
125 	__u8   state;
126 	__u16  flags;
127 	__u8   mode;
128 	__u8   count;
129 	__u8   pkt_id;
130 	__u32  serial_num;
131 	struct timer_list timer;
132 	struct usb_serial_port *port;
133 	int    seq_counter;
134 	int    insize;
135 	int    outsize;
136 	__u8   inbuffer [GPS_IN_BUFSIZ];  /* tty -> usb */
137 	__u8   outbuffer[GPS_OUT_BUFSIZ]; /* usb -> tty */
138 	__u8   privpkt[4*6];
139 	spinlock_t lock;
140 	struct list_head pktlist;
141 	struct usb_anchor write_urbs;
142 };
143 
144 
145 #define STATE_NEW            0
146 #define STATE_INITIAL_DELAY  1
147 #define STATE_TIMEOUT        2
148 #define STATE_SESSION_REQ1   3
149 #define STATE_SESSION_REQ2   4
150 #define STATE_ACTIVE         5
151 
152 #define STATE_RESET	     8
153 #define STATE_DISCONNECTED   9
154 #define STATE_WAIT_TTY_ACK  10
155 #define STATE_GSP_WAIT_DATA 11
156 
157 #define MODE_NATIVE          0
158 #define MODE_GARMIN_SERIAL   1
159 
160 /* Flags used in garmin_data.flags: */
161 #define FLAGS_SESSION_REPLY_MASK  0x00C0
162 #define FLAGS_SESSION_REPLY1_SEEN 0x0080
163 #define FLAGS_SESSION_REPLY2_SEEN 0x0040
164 #define FLAGS_BULK_IN_ACTIVE      0x0020
165 #define FLAGS_BULK_IN_RESTART     0x0010
166 #define FLAGS_THROTTLED           0x0008
167 #define APP_REQ_SEEN              0x0004
168 #define APP_RESP_SEEN             0x0002
169 #define CLEAR_HALT_REQUIRED       0x0001
170 
171 #define FLAGS_QUEUING             0x0100
172 #define FLAGS_DROP_DATA           0x0800
173 
174 #define FLAGS_GSP_SKIP            0x1000
175 #define FLAGS_GSP_DLESEEN         0x2000
176 
177 
178 
179 
180 
181 
182 /* function prototypes */
183 static int gsp_next_packet(struct garmin_data *garmin_data_p);
184 static int garmin_write_bulk(struct usb_serial_port *port,
185 			     const unsigned char *buf, int count,
186 			     int dismiss_ack);
187 
188 /* some special packets to be send or received */
189 static unsigned char const GARMIN_START_SESSION_REQ[]
190 	= { 0, 0, 0, 0,  5, 0, 0, 0, 0, 0, 0, 0 };
191 static unsigned char const GARMIN_START_SESSION_REPLY[]
192 	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
193 static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
194 	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
195 static unsigned char const GARMIN_APP_LAYER_REPLY[]
196 	= { 0x14, 0, 0, 0 };
197 static unsigned char const GARMIN_START_PVT_REQ[]
198 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
199 static unsigned char const GARMIN_STOP_PVT_REQ[]
200 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
201 static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
202 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
203 static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
204 	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
205 static unsigned char const PRIVATE_REQ[]
206 	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };
207 
208 
209 
210 static const struct usb_device_id id_table[] = {
211 	/* the same device id seems to be used by all
212 	   usb enabled GPS devices */
213 	{ USB_DEVICE(GARMIN_VENDOR_ID, 3) },
214 	{ }					/* Terminating entry */
215 };
216 MODULE_DEVICE_TABLE(usb, id_table);
217 
218 
219 static inline int getLayerId(const __u8 *usbPacket)
220 {
221 	return __le32_to_cpup((__le32 *)(usbPacket));
222 }
223 
224 static inline int getPacketId(const __u8 *usbPacket)
225 {
226 	return __le32_to_cpup((__le32 *)(usbPacket+4));
227 }
228 
229 static inline int getDataLength(const __u8 *usbPacket)
230 {
231 	return __le32_to_cpup((__le32 *)(usbPacket+8));
232 }
233 
234 
235 /*
236  * check if the usb-packet in buf contains an abort-transfer command.
237  * (if yes, all queued data will be dropped)
238  */
239 static inline int isAbortTrfCmnd(const unsigned char *buf)
240 {
241 	if (memcmp(buf, GARMIN_STOP_TRANSFER_REQ,
242 			sizeof(GARMIN_STOP_TRANSFER_REQ)) == 0 ||
243 	    memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2,
244 			sizeof(GARMIN_STOP_TRANSFER_REQ_V2)) == 0)
245 		return 1;
246 	else
247 		return 0;
248 }
249 
250 
251 
252 static void send_to_tty(struct usb_serial_port *port,
253 			char *data, unsigned int actual_length)
254 {
255 	if (actual_length) {
256 		usb_serial_debug_data(&port->dev, __func__, actual_length, data);
257 		tty_insert_flip_string(&port->port, data, actual_length);
258 		tty_flip_buffer_push(&port->port);
259 	}
260 }
261 
262 
263 /******************************************************************************
264  * packet queue handling
265  ******************************************************************************/
266 
267 /*
268  * queue a received (usb-)packet for later processing
269  */
270 static int pkt_add(struct garmin_data *garmin_data_p,
271 		   unsigned char *data, unsigned int data_length)
272 {
273 	int state = 0;
274 	int result = 0;
275 	unsigned long flags;
276 	struct garmin_packet *pkt;
277 
278 	/* process only packets containing data ... */
279 	if (data_length) {
280 		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
281 								GFP_ATOMIC);
282 		if (!pkt)
283 			return 0;
284 
285 		pkt->size = data_length;
286 		memcpy(pkt->data, data, data_length);
287 
288 		spin_lock_irqsave(&garmin_data_p->lock, flags);
289 		garmin_data_p->flags |= FLAGS_QUEUING;
290 		result = list_empty(&garmin_data_p->pktlist);
291 		pkt->seq = garmin_data_p->seq_counter++;
292 		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
293 		state = garmin_data_p->state;
294 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
295 
296 		dev_dbg(&garmin_data_p->port->dev,
297 			"%s - added: pkt: %d - %d bytes\n", __func__,
298 			pkt->seq, data_length);
299 
300 		/* in serial mode, if someone is waiting for data from
301 		   the device, convert and send the next packet to tty. */
302 		if (result && (state == STATE_GSP_WAIT_DATA))
303 			gsp_next_packet(garmin_data_p);
304 	}
305 	return result;
306 }
307 
308 
309 /* get the next pending packet */
310 static struct garmin_packet *pkt_pop(struct garmin_data *garmin_data_p)
311 {
312 	unsigned long flags;
313 	struct garmin_packet *result = NULL;
314 
315 	spin_lock_irqsave(&garmin_data_p->lock, flags);
316 	if (!list_empty(&garmin_data_p->pktlist)) {
317 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
318 		list_del(&result->list);
319 	}
320 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
321 	return result;
322 }
323 
324 
325 /* free up all queued data */
326 static void pkt_clear(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 	while (!list_empty(&garmin_data_p->pktlist)) {
333 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
334 		list_del(&result->list);
335 		kfree(result);
336 	}
337 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
338 }
339 
340 
341 /******************************************************************************
342  * garmin serial protocol handling handling
343  ******************************************************************************/
344 
345 /* send an ack packet back to the tty */
346 static int gsp_send_ack(struct garmin_data *garmin_data_p, __u8 pkt_id)
347 {
348 	__u8 pkt[10];
349 	__u8 cksum = 0;
350 	__u8 *ptr = pkt;
351 	unsigned  l = 0;
352 
353 	dev_dbg(&garmin_data_p->port->dev, "%s - pkt-id: 0x%X.\n", __func__,
354 			pkt_id);
355 
356 	*ptr++ = DLE;
357 	*ptr++ = ACK;
358 	cksum += ACK;
359 
360 	*ptr++ = 2;
361 	cksum += 2;
362 
363 	*ptr++ = pkt_id;
364 	cksum += pkt_id;
365 
366 	if (pkt_id == DLE)
367 		*ptr++ = DLE;
368 
369 	*ptr++ = 0;
370 	*ptr++ = (-cksum) & 0xFF;
371 	*ptr++ = DLE;
372 	*ptr++ = ETX;
373 
374 	l = ptr-pkt;
375 
376 	send_to_tty(garmin_data_p->port, pkt, l);
377 	return 0;
378 }
379 
380 
381 
382 /*
383  * called for a complete packet received from tty layer
384  *
385  * the complete packet (pktid ... cksum) is in garmin_data_p->inbuf starting
386  * at GSP_INITIAL_OFFSET.
387  *
388  * count - number of bytes in the input buffer including space reserved for
389  *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet
390  *         (including pkt-id, data-length a. cksum)
391  */
392 static int gsp_rec_packet(struct garmin_data *garmin_data_p, int count)
393 {
394 	struct device *dev = &garmin_data_p->port->dev;
395 	unsigned long flags;
396 	const __u8 *recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
397 	__le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;
398 	int cksum = 0;
399 	int n = 0;
400 	int pktid = recpkt[0];
401 	int size = recpkt[1];
402 
403 	usb_serial_debug_data(&garmin_data_p->port->dev, __func__,
404 			      count-GSP_INITIAL_OFFSET, recpkt);
405 
406 	if (size != (count-GSP_INITIAL_OFFSET-3)) {
407 		dev_dbg(dev, "%s - invalid size, expected %d bytes, got %d\n",
408 			__func__, size, (count-GSP_INITIAL_OFFSET-3));
409 		return -EINVPKT;
410 	}
411 
412 	cksum += *recpkt++;
413 	cksum += *recpkt++;
414 
415 	/* sanity check, remove after test ... */
416 	if ((__u8 *)&(usbdata[3]) != recpkt) {
417 		dev_dbg(dev, "%s - ptr mismatch %p - %p\n", __func__,
418 			&(usbdata[4]), recpkt);
419 		return -EINVPKT;
420 	}
421 
422 	while (n < size) {
423 		cksum += *recpkt++;
424 		n++;
425 	}
426 
427 	if (((cksum + *recpkt) & 0xff) != 0) {
428 		dev_dbg(dev, "%s - invalid checksum, expected %02x, got %02x\n",
429 			__func__, -cksum & 0xff, *recpkt);
430 		return -EINVPKT;
431 	}
432 
433 	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
434 	usbdata[1] = __cpu_to_le32(pktid);
435 	usbdata[2] = __cpu_to_le32(size);
436 
437 	garmin_write_bulk(garmin_data_p->port, garmin_data_p->inbuffer,
438 			   GARMIN_PKTHDR_LENGTH+size, 0);
439 
440 	/* if this was an abort-transfer command, flush all
441 	   queued data. */
442 	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
443 		spin_lock_irqsave(&garmin_data_p->lock, flags);
444 		garmin_data_p->flags |= FLAGS_DROP_DATA;
445 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
446 		pkt_clear(garmin_data_p);
447 	}
448 
449 	return count;
450 }
451 
452 
453 
454 /*
455  * Called for data received from tty
456  *
457  * buf contains the data read, it may span more than one packet or even
458  * incomplete packets
459  *
460  * input record should be a serial-record, but it may not be complete.
461  * Copy it into our local buffer, until an etx is seen (or an error
462  * occurs).
463  * Once the record is complete, convert into a usb packet and send it
464  * to the bulk pipe, send an ack back to the tty.
465  *
466  * If the input is an ack, just send the last queued packet to the
467  * tty layer.
468  *
469  * if the input is an abort command, drop all queued data.
470  */
471 
472 static int gsp_receive(struct garmin_data *garmin_data_p,
473 		       const unsigned char *buf, int count)
474 {
475 	struct device *dev = &garmin_data_p->port->dev;
476 	unsigned long flags;
477 	int offs = 0;
478 	int ack_or_nak_seen = 0;
479 	__u8 *dest;
480 	int size;
481 	/* dleSeen: set if last byte read was a DLE */
482 	int dleSeen;
483 	/* skip: if set, skip incoming data until possible start of
484 	 *       new packet
485 	 */
486 	int skip;
487 	__u8 data;
488 
489 	spin_lock_irqsave(&garmin_data_p->lock, flags);
490 	dest = garmin_data_p->inbuffer;
491 	size = garmin_data_p->insize;
492 	dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
493 	skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
494 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
495 
496 	/* dev_dbg(dev, "%s - dle=%d skip=%d size=%d count=%d\n",
497 		__func__, dleSeen, skip, size, count); */
498 
499 	if (size == 0)
500 		size = GSP_INITIAL_OFFSET;
501 
502 	while (offs < count) {
503 
504 		data = *(buf+offs);
505 		offs++;
506 
507 		if (data == DLE) {
508 			if (skip) { /* start of a new pkt */
509 				skip = 0;
510 				size = GSP_INITIAL_OFFSET;
511 				dleSeen = 1;
512 			} else if (dleSeen) {
513 				dest[size++] = data;
514 				dleSeen = 0;
515 			} else {
516 				dleSeen = 1;
517 			}
518 		} else if (data == ETX) {
519 			if (dleSeen) {
520 				/* packet complete */
521 
522 				data = dest[GSP_INITIAL_OFFSET];
523 
524 				if (data == ACK) {
525 					ack_or_nak_seen = ACK;
526 					dev_dbg(dev, "ACK packet complete.\n");
527 				} else if (data == NAK) {
528 					ack_or_nak_seen = NAK;
529 					dev_dbg(dev, "NAK packet complete.\n");
530 				} else {
531 					dev_dbg(dev, "packet complete - id=0x%X.\n",
532 							data);
533 					gsp_rec_packet(garmin_data_p, size);
534 				}
535 
536 				skip = 1;
537 				size = GSP_INITIAL_OFFSET;
538 				dleSeen = 0;
539 			} else {
540 				dest[size++] = data;
541 			}
542 		} else if (!skip) {
543 
544 			if (dleSeen) {
545 				size = GSP_INITIAL_OFFSET;
546 				dleSeen = 0;
547 			}
548 
549 			dest[size++] = data;
550 		}
551 
552 		if (size >= GPS_IN_BUFSIZ) {
553 			dev_dbg(dev, "%s - packet too large.\n", __func__);
554 			skip = 1;
555 			size = GSP_INITIAL_OFFSET;
556 			dleSeen = 0;
557 		}
558 	}
559 
560 	spin_lock_irqsave(&garmin_data_p->lock, flags);
561 
562 	garmin_data_p->insize = size;
563 
564 	/* copy flags back to structure */
565 	if (skip)
566 		garmin_data_p->flags |= FLAGS_GSP_SKIP;
567 	else
568 		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;
569 
570 	if (dleSeen)
571 		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
572 	else
573 		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;
574 
575 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
576 
577 	if (ack_or_nak_seen) {
578 		if (gsp_next_packet(garmin_data_p) > 0)
579 			garmin_data_p->state = STATE_ACTIVE;
580 		else
581 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
582 	}
583 	return count;
584 }
585 
586 
587 
588 /*
589  * Sends a usb packet to the tty
590  *
591  * Assumes, that all packages and at an usb-packet boundary.
592  *
593  * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
594  */
595 static int gsp_send(struct garmin_data *garmin_data_p,
596 		    const unsigned char *buf, int count)
597 {
598 	struct device *dev = &garmin_data_p->port->dev;
599 	const unsigned char *src;
600 	unsigned char *dst;
601 	int pktid = 0;
602 	int datalen = 0;
603 	int cksum = 0;
604 	int i = 0;
605 	int k;
606 
607 	dev_dbg(dev, "%s - state %d - %d bytes.\n", __func__,
608 		garmin_data_p->state, count);
609 
610 	k = garmin_data_p->outsize;
611 	if ((k+count) > GPS_OUT_BUFSIZ) {
612 		dev_dbg(dev, "packet too large\n");
613 		garmin_data_p->outsize = 0;
614 		return -4;
615 	}
616 
617 	memcpy(garmin_data_p->outbuffer+k, buf, count);
618 	k += count;
619 	garmin_data_p->outsize = k;
620 
621 	if (k >= GARMIN_PKTHDR_LENGTH) {
622 		pktid  = getPacketId(garmin_data_p->outbuffer);
623 		datalen = getDataLength(garmin_data_p->outbuffer);
624 		i = GARMIN_PKTHDR_LENGTH + datalen;
625 		if (k < i)
626 			return 0;
627 	} else {
628 		return 0;
629 	}
630 
631 	dev_dbg(dev, "%s - %d bytes in buffer, %d bytes in pkt.\n", __func__, k, i);
632 
633 	/* garmin_data_p->outbuffer now contains a complete packet */
634 
635 	usb_serial_debug_data(&garmin_data_p->port->dev, __func__, k,
636 			      garmin_data_p->outbuffer);
637 
638 	garmin_data_p->outsize = 0;
639 
640 	if (getLayerId(garmin_data_p->outbuffer) != GARMIN_LAYERID_APPL) {
641 		dev_dbg(dev, "not an application packet (%d)\n",
642 				getLayerId(garmin_data_p->outbuffer));
643 		return -1;
644 	}
645 
646 	if (pktid > 255) {
647 		dev_dbg(dev, "packet-id %d too large\n", pktid);
648 		return -2;
649 	}
650 
651 	if (datalen > 255) {
652 		dev_dbg(dev, "packet-size %d too large\n", datalen);
653 		return -3;
654 	}
655 
656 	/* the serial protocol should be able to handle this packet */
657 
658 	k = 0;
659 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
660 	for (i = 0; i < datalen; i++) {
661 		if (*src++ == DLE)
662 			k++;
663 	}
664 
665 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
666 	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
667 		/* can't add stuffing DLEs in place, move data to end
668 		   of buffer ... */
669 		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
670 		memcpy(dst, src, datalen);
671 		src = dst;
672 	}
673 
674 	dst = garmin_data_p->outbuffer;
675 
676 	*dst++ = DLE;
677 	*dst++ = pktid;
678 	cksum += pktid;
679 	*dst++ = datalen;
680 	cksum += datalen;
681 	if (datalen == DLE)
682 		*dst++ = DLE;
683 
684 	for (i = 0; i < datalen; i++) {
685 		__u8 c = *src++;
686 		*dst++ = c;
687 		cksum += c;
688 		if (c == DLE)
689 			*dst++ = DLE;
690 	}
691 
692 	cksum = -cksum & 0xFF;
693 	*dst++ = cksum;
694 	if (cksum == DLE)
695 		*dst++ = DLE;
696 	*dst++ = DLE;
697 	*dst++ = ETX;
698 
699 	i = dst-garmin_data_p->outbuffer;
700 
701 	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);
702 
703 	garmin_data_p->pkt_id = pktid;
704 	garmin_data_p->state  = STATE_WAIT_TTY_ACK;
705 
706 	return i;
707 }
708 
709 
710 /*
711  * Process the next pending data packet - if there is one
712  */
713 static int gsp_next_packet(struct garmin_data *garmin_data_p)
714 {
715 	int result = 0;
716 	struct garmin_packet *pkt = NULL;
717 
718 	while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
719 		dev_dbg(&garmin_data_p->port->dev, "%s - next pkt: %d\n", __func__, pkt->seq);
720 		result = gsp_send(garmin_data_p, pkt->data, pkt->size);
721 		if (result > 0) {
722 			kfree(pkt);
723 			return result;
724 		}
725 		kfree(pkt);
726 	}
727 	return result;
728 }
729 
730 
731 
732 /******************************************************************************
733  * garmin native mode
734  ******************************************************************************/
735 
736 
737 /*
738  * Called for data received from tty
739  *
740  * The input data is expected to be in garmin usb-packet format.
741  *
742  * buf contains the data read, it may span more than one packet
743  * or even incomplete packets
744  */
745 static int nat_receive(struct garmin_data *garmin_data_p,
746 		       const unsigned char *buf, int count)
747 {
748 	unsigned long flags;
749 	__u8 *dest;
750 	int offs = 0;
751 	int result = count;
752 	int len;
753 
754 	while (offs < count) {
755 		/* if buffer contains header, copy rest of data */
756 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
757 			len = GARMIN_PKTHDR_LENGTH
758 			      +getDataLength(garmin_data_p->inbuffer);
759 		else
760 			len = GARMIN_PKTHDR_LENGTH;
761 
762 		if (len >= GPS_IN_BUFSIZ) {
763 			/* seems to be an invalid packet, ignore rest
764 			   of input */
765 			dev_dbg(&garmin_data_p->port->dev,
766 				"%s - packet size too large: %d\n",
767 				__func__, len);
768 			garmin_data_p->insize = 0;
769 			count = 0;
770 			result = -EINVPKT;
771 		} else {
772 			len -= garmin_data_p->insize;
773 			if (len > (count-offs))
774 				len = (count-offs);
775 			if (len > 0) {
776 				dest = garmin_data_p->inbuffer
777 						+ garmin_data_p->insize;
778 				memcpy(dest, buf+offs, len);
779 				garmin_data_p->insize += len;
780 				offs += len;
781 			}
782 		}
783 
784 		/* do we have a complete packet ? */
785 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
786 			len = GARMIN_PKTHDR_LENGTH+
787 			   getDataLength(garmin_data_p->inbuffer);
788 			if (garmin_data_p->insize >= len) {
789 				garmin_write_bulk(garmin_data_p->port,
790 						   garmin_data_p->inbuffer,
791 						   len, 0);
792 				garmin_data_p->insize = 0;
793 
794 				/* if this was an abort-transfer command,
795 				   flush all queued data. */
796 				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
797 					spin_lock_irqsave(&garmin_data_p->lock,
798 									flags);
799 					garmin_data_p->flags |= FLAGS_DROP_DATA;
800 					spin_unlock_irqrestore(
801 						&garmin_data_p->lock, flags);
802 					pkt_clear(garmin_data_p);
803 				}
804 			}
805 		}
806 	}
807 	return result;
808 }
809 
810 
811 /******************************************************************************
812  * private packets
813  ******************************************************************************/
814 
815 static void priv_status_resp(struct usb_serial_port *port)
816 {
817 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
818 	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;
819 
820 	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
821 	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
822 	pkt[2] = __cpu_to_le32(12);
823 	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
824 	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
825 	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);
826 
827 	send_to_tty(port, (__u8 *)pkt, 6 * 4);
828 }
829 
830 
831 /******************************************************************************
832  * Garmin specific driver functions
833  ******************************************************************************/
834 
835 static int process_resetdev_request(struct usb_serial_port *port)
836 {
837 	unsigned long flags;
838 	int status;
839 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
840 
841 	spin_lock_irqsave(&garmin_data_p->lock, flags);
842 	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
843 	garmin_data_p->state = STATE_RESET;
844 	garmin_data_p->serial_num = 0;
845 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
846 
847 	usb_kill_urb(port->interrupt_in_urb);
848 	dev_dbg(&port->dev, "%s - usb_reset_device\n", __func__);
849 	status = usb_reset_device(port->serial->dev);
850 	if (status)
851 		dev_dbg(&port->dev, "%s - usb_reset_device failed: %d\n",
852 			__func__, status);
853 	return status;
854 }
855 
856 
857 
858 /*
859  * clear all cached data
860  */
861 static int garmin_clear(struct garmin_data *garmin_data_p)
862 {
863 	unsigned long flags;
864 
865 	/* flush all queued data */
866 	pkt_clear(garmin_data_p);
867 
868 	spin_lock_irqsave(&garmin_data_p->lock, flags);
869 	garmin_data_p->insize = 0;
870 	garmin_data_p->outsize = 0;
871 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
872 
873 	return 0;
874 }
875 
876 
877 static int garmin_init_session(struct usb_serial_port *port)
878 {
879 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
880 	int status = 0;
881 	int i = 0;
882 
883 	if (status == 0) {
884 		usb_kill_urb(port->interrupt_in_urb);
885 
886 		status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
887 		if (status) {
888 			dev_err(&port->dev,
889 					"failed to submit interrupt urb: %d\n",
890 					status);
891 		}
892 	}
893 
894 	/*
895 	 * using the initialization method from gpsbabel. See comments in
896 	 * gpsbabel/jeeps/gpslibusb.c gusb_reset_toggles()
897 	 */
898 	if (status == 0) {
899 		dev_dbg(&port->dev, "%s - starting session ...\n", __func__);
900 		garmin_data_p->state = STATE_ACTIVE;
901 
902 		for (i = 0; i < 3; i++) {
903 			status = garmin_write_bulk(port,
904 					GARMIN_START_SESSION_REQ,
905 					sizeof(GARMIN_START_SESSION_REQ), 0);
906 
907 			if (status < 0)
908 				goto err_kill_urbs;
909 		}
910 
911 		if (status > 0)
912 			status = 0;
913 	}
914 
915 	return status;
916 
917 err_kill_urbs:
918 	usb_kill_anchored_urbs(&garmin_data_p->write_urbs);
919 	usb_kill_urb(port->interrupt_in_urb);
920 
921 	return status;
922 }
923 
924 
925 
926 static int garmin_open(struct tty_struct *tty, struct usb_serial_port *port)
927 {
928 	unsigned long flags;
929 	int status = 0;
930 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
931 
932 	spin_lock_irqsave(&garmin_data_p->lock, flags);
933 	garmin_data_p->mode  = initial_mode;
934 	garmin_data_p->count = 0;
935 	garmin_data_p->flags &= FLAGS_SESSION_REPLY1_SEEN;
936 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
937 
938 	/* shutdown any bulk reads that might be going on */
939 	usb_kill_urb(port->read_urb);
940 
941 	if (garmin_data_p->state == STATE_RESET)
942 		status = garmin_init_session(port);
943 
944 	garmin_data_p->state = STATE_ACTIVE;
945 	return status;
946 }
947 
948 
949 static void garmin_close(struct usb_serial_port *port)
950 {
951 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
952 
953 	dev_dbg(&port->dev, "%s - mode=%d state=%d flags=0x%X\n",
954 		__func__, garmin_data_p->mode, garmin_data_p->state,
955 		garmin_data_p->flags);
956 
957 	garmin_clear(garmin_data_p);
958 
959 	/* shutdown our urbs */
960 	usb_kill_urb(port->read_urb);
961 	usb_kill_anchored_urbs(&garmin_data_p->write_urbs);
962 
963 	/* keep reset state so we know that we must start a new session */
964 	if (garmin_data_p->state != STATE_RESET)
965 		garmin_data_p->state = STATE_DISCONNECTED;
966 }
967 
968 
969 static void garmin_write_bulk_callback(struct urb *urb)
970 {
971 	struct usb_serial_port *port = urb->context;
972 
973 	if (port) {
974 		struct garmin_data *garmin_data_p =
975 					usb_get_serial_port_data(port);
976 
977 		if (getLayerId(urb->transfer_buffer) == GARMIN_LAYERID_APPL) {
978 
979 			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
980 				gsp_send_ack(garmin_data_p,
981 					((__u8 *)urb->transfer_buffer)[4]);
982 			}
983 		}
984 		usb_serial_port_softint(port);
985 	}
986 
987 	/* Ignore errors that resulted from garmin_write_bulk with
988 	   dismiss_ack = 1 */
989 
990 	/* free up the transfer buffer, as usb_free_urb() does not do this */
991 	kfree(urb->transfer_buffer);
992 }
993 
994 
995 static int garmin_write_bulk(struct usb_serial_port *port,
996 			      const unsigned char *buf, int count,
997 			      int dismiss_ack)
998 {
999 	unsigned long flags;
1000 	struct usb_serial *serial = port->serial;
1001 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1002 	struct urb *urb;
1003 	unsigned char *buffer;
1004 	int status;
1005 
1006 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1007 	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
1008 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1009 
1010 	buffer = kmalloc(count, GFP_ATOMIC);
1011 	if (!buffer)
1012 		return -ENOMEM;
1013 
1014 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1015 	if (!urb) {
1016 		kfree(buffer);
1017 		return -ENOMEM;
1018 	}
1019 
1020 	memcpy(buffer, buf, count);
1021 
1022 	usb_serial_debug_data(&port->dev, __func__, count, buffer);
1023 
1024 	usb_fill_bulk_urb(urb, serial->dev,
1025 				usb_sndbulkpipe(serial->dev,
1026 					port->bulk_out_endpointAddress),
1027 				buffer, count,
1028 				garmin_write_bulk_callback,
1029 				dismiss_ack ? NULL : port);
1030 	urb->transfer_flags |= URB_ZERO_PACKET;
1031 
1032 	if (getLayerId(buffer) == GARMIN_LAYERID_APPL) {
1033 
1034 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1035 		garmin_data_p->flags |= APP_REQ_SEEN;
1036 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1037 
1038 		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
1039 			pkt_clear(garmin_data_p);
1040 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
1041 		}
1042 	}
1043 
1044 	/* send it down the pipe */
1045 	usb_anchor_urb(urb, &garmin_data_p->write_urbs);
1046 	status = usb_submit_urb(urb, GFP_ATOMIC);
1047 	if (status) {
1048 		dev_err(&port->dev,
1049 		   "%s - usb_submit_urb(write bulk) failed with status = %d\n",
1050 				__func__, status);
1051 		count = status;
1052 		usb_unanchor_urb(urb);
1053 		kfree(buffer);
1054 	}
1055 
1056 	/* we are done with this urb, so let the host driver
1057 	 * really free it when it is finished with it */
1058 	usb_free_urb(urb);
1059 
1060 	return count;
1061 }
1062 
1063 static int garmin_write(struct tty_struct *tty, struct usb_serial_port *port,
1064 					 const unsigned char *buf, int count)
1065 {
1066 	struct device *dev = &port->dev;
1067 	int pktid, pktsiz, len;
1068 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1069 	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;
1070 
1071 	usb_serial_debug_data(dev, __func__, count, buf);
1072 
1073 	if (garmin_data_p->state == STATE_RESET)
1074 		return -EIO;
1075 
1076 	/* check for our private packets */
1077 	if (count >= GARMIN_PKTHDR_LENGTH) {
1078 		len = PRIVPKTSIZ;
1079 		if (count < len)
1080 			len = count;
1081 
1082 		memcpy(garmin_data_p->privpkt, buf, len);
1083 
1084 		pktsiz = getDataLength(garmin_data_p->privpkt);
1085 		pktid  = getPacketId(garmin_data_p->privpkt);
1086 
1087 		if (count == (GARMIN_PKTHDR_LENGTH + pktsiz) &&
1088 				getLayerId(garmin_data_p->privpkt) ==
1089 						GARMIN_LAYERID_PRIVATE) {
1090 
1091 			dev_dbg(dev, "%s - processing private request %d\n",
1092 				__func__, pktid);
1093 
1094 			/* drop all unfinished transfers */
1095 			garmin_clear(garmin_data_p);
1096 
1097 			switch (pktid) {
1098 			case PRIV_PKTID_SET_MODE:
1099 				if (pktsiz != 4)
1100 					return -EINVPKT;
1101 				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
1102 				dev_dbg(dev, "%s - mode set to %d\n",
1103 					__func__, garmin_data_p->mode);
1104 				break;
1105 
1106 			case PRIV_PKTID_INFO_REQ:
1107 				priv_status_resp(port);
1108 				break;
1109 
1110 			case PRIV_PKTID_RESET_REQ:
1111 				process_resetdev_request(port);
1112 				break;
1113 
1114 			case PRIV_PKTID_SET_DEF_MODE:
1115 				if (pktsiz != 4)
1116 					return -EINVPKT;
1117 				initial_mode = __le32_to_cpu(privpkt[3]);
1118 				dev_dbg(dev, "%s - initial_mode set to %d\n",
1119 					__func__,
1120 					garmin_data_p->mode);
1121 				break;
1122 			}
1123 			return count;
1124 		}
1125 	}
1126 
1127 	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1128 		return gsp_receive(garmin_data_p, buf, count);
1129 	} else {	/* MODE_NATIVE */
1130 		return nat_receive(garmin_data_p, buf, count);
1131 	}
1132 }
1133 
1134 
1135 static int garmin_write_room(struct tty_struct *tty)
1136 {
1137 	struct usb_serial_port *port = tty->driver_data;
1138 	/*
1139 	 * Report back the bytes currently available in the output buffer.
1140 	 */
1141 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1142 	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
1143 }
1144 
1145 
1146 static void garmin_read_process(struct garmin_data *garmin_data_p,
1147 				 unsigned char *data, unsigned data_length,
1148 				 int bulk_data)
1149 {
1150 	unsigned long flags;
1151 
1152 	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
1153 		/* abort-transfer cmd is active */
1154 		dev_dbg(&garmin_data_p->port->dev, "%s - pkt dropped\n", __func__);
1155 	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
1156 		garmin_data_p->state != STATE_RESET) {
1157 
1158 		/* if throttling is active or postprecessing is required
1159 		   put the received data in the input queue, otherwise
1160 		   send it directly to the tty port */
1161 		if (garmin_data_p->flags & FLAGS_QUEUING) {
1162 			pkt_add(garmin_data_p, data, data_length);
1163 		} else if (bulk_data ||
1164 			   getLayerId(data) == GARMIN_LAYERID_APPL) {
1165 
1166 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1167 			garmin_data_p->flags |= APP_RESP_SEEN;
1168 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1169 
1170 			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1171 				pkt_add(garmin_data_p, data, data_length);
1172 			} else {
1173 				send_to_tty(garmin_data_p->port, data,
1174 						data_length);
1175 			}
1176 		}
1177 		/* ignore system layer packets ... */
1178 	}
1179 }
1180 
1181 
1182 static void garmin_read_bulk_callback(struct urb *urb)
1183 {
1184 	unsigned long flags;
1185 	struct usb_serial_port *port = urb->context;
1186 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1187 	unsigned char *data = urb->transfer_buffer;
1188 	int status = urb->status;
1189 	int retval;
1190 
1191 	if (status) {
1192 		dev_dbg(&urb->dev->dev, "%s - nonzero read bulk status received: %d\n",
1193 			__func__, status);
1194 		return;
1195 	}
1196 
1197 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
1198 
1199 	garmin_read_process(garmin_data_p, data, urb->actual_length, 1);
1200 
1201 	if (urb->actual_length == 0 &&
1202 			(garmin_data_p->flags & FLAGS_BULK_IN_RESTART) != 0) {
1203 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1204 		garmin_data_p->flags &= ~FLAGS_BULK_IN_RESTART;
1205 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1206 		retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1207 		if (retval)
1208 			dev_err(&port->dev,
1209 				"%s - failed resubmitting read urb, error %d\n",
1210 				__func__, retval);
1211 	} else if (urb->actual_length > 0) {
1212 		/* Continue trying to read until nothing more is received  */
1213 		if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1214 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1215 			if (retval)
1216 				dev_err(&port->dev,
1217 					"%s - failed resubmitting read urb, error %d\n",
1218 					__func__, retval);
1219 		}
1220 	} else {
1221 		dev_dbg(&port->dev, "%s - end of bulk data\n", __func__);
1222 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1223 		garmin_data_p->flags &= ~FLAGS_BULK_IN_ACTIVE;
1224 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1225 	}
1226 }
1227 
1228 
1229 static void garmin_read_int_callback(struct urb *urb)
1230 {
1231 	unsigned long flags;
1232 	int retval;
1233 	struct usb_serial_port *port = urb->context;
1234 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1235 	unsigned char *data = urb->transfer_buffer;
1236 	int status = urb->status;
1237 
1238 	switch (status) {
1239 	case 0:
1240 		/* success */
1241 		break;
1242 	case -ECONNRESET:
1243 	case -ENOENT:
1244 	case -ESHUTDOWN:
1245 		/* this urb is terminated, clean up */
1246 		dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
1247 			__func__, status);
1248 		return;
1249 	default:
1250 		dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
1251 			__func__, status);
1252 		return;
1253 	}
1254 
1255 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
1256 			      urb->transfer_buffer);
1257 
1258 	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
1259 		memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
1260 				sizeof(GARMIN_BULK_IN_AVAIL_REPLY)) == 0) {
1261 
1262 		dev_dbg(&port->dev, "%s - bulk data available.\n", __func__);
1263 
1264 		if ((garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE) == 0) {
1265 
1266 			/* bulk data available */
1267 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1268 			if (retval) {
1269 				dev_err(&port->dev,
1270 				 "%s - failed submitting read urb, error %d\n",
1271 							__func__, retval);
1272 			} else {
1273 				spin_lock_irqsave(&garmin_data_p->lock, flags);
1274 				garmin_data_p->flags |= FLAGS_BULK_IN_ACTIVE;
1275 				spin_unlock_irqrestore(&garmin_data_p->lock,
1276 									flags);
1277 			}
1278 		} else {
1279 			/* bulk-in transfer still active */
1280 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1281 			garmin_data_p->flags |= FLAGS_BULK_IN_RESTART;
1282 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1283 		}
1284 
1285 	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
1286 			 && memcmp(data, GARMIN_START_SESSION_REPLY,
1287 				 sizeof(GARMIN_START_SESSION_REPLY)) == 0) {
1288 
1289 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1290 		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
1291 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1292 
1293 		/* save the serial number */
1294 		garmin_data_p->serial_num = __le32_to_cpup(
1295 					(__le32 *)(data+GARMIN_PKTHDR_LENGTH));
1296 
1297 		dev_dbg(&port->dev, "%s - start-of-session reply seen - serial %u.\n",
1298 			__func__, garmin_data_p->serial_num);
1299 	}
1300 
1301 	garmin_read_process(garmin_data_p, data, urb->actual_length, 0);
1302 
1303 	retval = usb_submit_urb(urb, GFP_ATOMIC);
1304 	if (retval)
1305 		dev_err(&urb->dev->dev,
1306 			"%s - Error %d submitting interrupt urb\n",
1307 			__func__, retval);
1308 }
1309 
1310 
1311 /*
1312  * Sends the next queued packt to the tty port (garmin native mode only)
1313  * and then sets a timer to call itself again until all queued data
1314  * is sent.
1315  */
1316 static int garmin_flush_queue(struct garmin_data *garmin_data_p)
1317 {
1318 	unsigned long flags;
1319 	struct garmin_packet *pkt;
1320 
1321 	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1322 		pkt = pkt_pop(garmin_data_p);
1323 		if (pkt != NULL) {
1324 			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
1325 			kfree(pkt);
1326 			mod_timer(&garmin_data_p->timer, (1)+jiffies);
1327 
1328 		} else {
1329 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1330 			garmin_data_p->flags &= ~FLAGS_QUEUING;
1331 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1332 		}
1333 	}
1334 	return 0;
1335 }
1336 
1337 
1338 static void garmin_throttle(struct tty_struct *tty)
1339 {
1340 	struct usb_serial_port *port = tty->driver_data;
1341 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1342 
1343 	/* set flag, data received will be put into a queue
1344 	   for later processing */
1345 	spin_lock_irq(&garmin_data_p->lock);
1346 	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
1347 	spin_unlock_irq(&garmin_data_p->lock);
1348 }
1349 
1350 
1351 static void garmin_unthrottle(struct tty_struct *tty)
1352 {
1353 	struct usb_serial_port *port = tty->driver_data;
1354 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1355 	int status;
1356 
1357 	spin_lock_irq(&garmin_data_p->lock);
1358 	garmin_data_p->flags &= ~FLAGS_THROTTLED;
1359 	spin_unlock_irq(&garmin_data_p->lock);
1360 
1361 	/* in native mode send queued data to tty, in
1362 	   serial mode nothing needs to be done here */
1363 	if (garmin_data_p->mode == MODE_NATIVE)
1364 		garmin_flush_queue(garmin_data_p);
1365 
1366 	if ((garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE) != 0) {
1367 		status = usb_submit_urb(port->read_urb, GFP_KERNEL);
1368 		if (status)
1369 			dev_err(&port->dev,
1370 				"%s - failed resubmitting read urb, error %d\n",
1371 				__func__, status);
1372 	}
1373 }
1374 
1375 /*
1376  * The timer is currently only used to send queued packets to
1377  * the tty in cases where the protocol provides no own handshaking
1378  * to initiate the transfer.
1379  */
1380 static void timeout_handler(struct timer_list *t)
1381 {
1382 	struct garmin_data *garmin_data_p = from_timer(garmin_data_p, t, timer);
1383 
1384 	/* send the next queued packet to the tty port */
1385 	if (garmin_data_p->mode == MODE_NATIVE)
1386 		if (garmin_data_p->flags & FLAGS_QUEUING)
1387 			garmin_flush_queue(garmin_data_p);
1388 }
1389 
1390 
1391 
1392 static int garmin_port_probe(struct usb_serial_port *port)
1393 {
1394 	int status;
1395 	struct garmin_data *garmin_data_p;
1396 
1397 	garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
1398 	if (!garmin_data_p)
1399 		return -ENOMEM;
1400 
1401 	timer_setup(&garmin_data_p->timer, timeout_handler, 0);
1402 	spin_lock_init(&garmin_data_p->lock);
1403 	INIT_LIST_HEAD(&garmin_data_p->pktlist);
1404 	garmin_data_p->port = port;
1405 	garmin_data_p->state = 0;
1406 	garmin_data_p->flags = 0;
1407 	garmin_data_p->count = 0;
1408 	init_usb_anchor(&garmin_data_p->write_urbs);
1409 	usb_set_serial_port_data(port, garmin_data_p);
1410 
1411 	status = garmin_init_session(port);
1412 	if (status)
1413 		goto err_free;
1414 
1415 	return 0;
1416 err_free:
1417 	kfree(garmin_data_p);
1418 
1419 	return status;
1420 }
1421 
1422 
1423 static int garmin_port_remove(struct usb_serial_port *port)
1424 {
1425 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1426 
1427 	usb_kill_anchored_urbs(&garmin_data_p->write_urbs);
1428 	usb_kill_urb(port->interrupt_in_urb);
1429 	del_timer_sync(&garmin_data_p->timer);
1430 	kfree(garmin_data_p);
1431 	return 0;
1432 }
1433 
1434 
1435 /* All of the device info needed */
1436 static struct usb_serial_driver garmin_device = {
1437 	.driver = {
1438 		.owner       = THIS_MODULE,
1439 		.name        = "garmin_gps",
1440 	},
1441 	.description         = "Garmin GPS usb/tty",
1442 	.id_table            = id_table,
1443 	.num_ports           = 1,
1444 	.open                = garmin_open,
1445 	.close               = garmin_close,
1446 	.throttle            = garmin_throttle,
1447 	.unthrottle          = garmin_unthrottle,
1448 	.port_probe		= garmin_port_probe,
1449 	.port_remove		= garmin_port_remove,
1450 	.write               = garmin_write,
1451 	.write_room          = garmin_write_room,
1452 	.write_bulk_callback = garmin_write_bulk_callback,
1453 	.read_bulk_callback  = garmin_read_bulk_callback,
1454 	.read_int_callback   = garmin_read_int_callback,
1455 };
1456 
1457 static struct usb_serial_driver * const serial_drivers[] = {
1458 	&garmin_device, NULL
1459 };
1460 
1461 module_usb_serial_driver(serial_drivers, id_table);
1462 
1463 MODULE_AUTHOR(DRIVER_AUTHOR);
1464 MODULE_DESCRIPTION(DRIVER_DESC);
1465 MODULE_LICENSE("GPL");
1466 
1467 module_param(initial_mode, int, S_IRUGO);
1468 MODULE_PARM_DESC(initial_mode, "Initial mode");
1469