xref: /linux/drivers/usb/serial/garmin_gps.c (revision 59d33f2fc2d63796296b1b76143e039d6e7cf532)
1 /*
2  * Garmin GPS driver
3  *
4  * Copyright (C) 2006-2011 Hermann Kneissel herkne@gmx.de
5  *
6  * The latest version of the driver can be found at
7  * http://sourceforge.net/projects/garmin-gps/
8  *
9  * This driver has been derived from v2.1 of the visor driver.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111 USA
24  */
25 
26 #include <linux/kernel.h>
27 #include <linux/errno.h>
28 #include <linux/init.h>
29 #include <linux/slab.h>
30 #include <linux/timer.h>
31 #include <linux/tty.h>
32 #include <linux/tty_driver.h>
33 #include <linux/tty_flip.h>
34 #include <linux/module.h>
35 #include <linux/spinlock.h>
36 #include <linux/uaccess.h>
37 #include <linux/atomic.h>
38 #include <linux/usb.h>
39 #include <linux/usb/serial.h>
40 
41 /* the mode to be set when the port ist opened */
42 static int initial_mode = 1;
43 
44 /* debug flag */
45 static bool debug;
46 
47 #define GARMIN_VENDOR_ID             0x091E
48 
49 /*
50  * Version Information
51  */
52 
53 #define VERSION_MAJOR	0
54 #define VERSION_MINOR	36
55 
56 #define _STR(s) #s
57 #define _DRIVER_VERSION(a, b) "v" _STR(a) "." _STR(b)
58 #define DRIVER_VERSION _DRIVER_VERSION(VERSION_MAJOR, VERSION_MINOR)
59 #define DRIVER_AUTHOR "hermann kneissel"
60 #define DRIVER_DESC "garmin gps driver"
61 
62 /* error codes returned by the driver */
63 #define EINVPKT	1000	/* invalid packet structure */
64 
65 
66 /* size of the header of a packet using the usb protocol */
67 #define GARMIN_PKTHDR_LENGTH	12
68 
69 /* max. possible size of a packet using the serial protocol */
70 #define MAX_SERIAL_PKT_SIZ (3 + 255 + 3)
71 
72 /*  max. possible size of a packet with worst case stuffing */
73 #define MAX_SERIAL_PKT_SIZ_STUFFED (MAX_SERIAL_PKT_SIZ + 256)
74 
75 /* size of a buffer able to hold a complete (no stuffing) packet
76  * (the document protocol does not contain packets with a larger
77  *  size, but in theory a packet may be 64k+12 bytes - if in
78  *  later protocol versions larger packet sizes occur, this value
79  *  should be increased accordingly, so the input buffer is always
80  *  large enough the store a complete packet inclusive header) */
81 #define GPS_IN_BUFSIZ  (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ)
82 
83 /* size of a buffer able to hold a complete (incl. stuffing) packet */
84 #define GPS_OUT_BUFSIZ (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ_STUFFED)
85 
86 /* where to place the packet id of a serial packet, so we can
87  * prepend the usb-packet header without the need to move the
88  * packets data */
89 #define GSP_INITIAL_OFFSET (GARMIN_PKTHDR_LENGTH-2)
90 
91 /* max. size of incoming private packets (header+1 param) */
92 #define PRIVPKTSIZ (GARMIN_PKTHDR_LENGTH+4)
93 
94 #define GARMIN_LAYERID_TRANSPORT  0
95 #define GARMIN_LAYERID_APPL      20
96 /* our own layer-id to use for some control mechanisms */
97 #define GARMIN_LAYERID_PRIVATE	0x01106E4B
98 
99 #define GARMIN_PKTID_PVT_DATA	51
100 #define GARMIN_PKTID_L001_COMMAND_DATA 10
101 
102 #define CMND_ABORT_TRANSFER 0
103 
104 /* packet ids used in private layer */
105 #define PRIV_PKTID_SET_DEBUG	1
106 #define PRIV_PKTID_SET_MODE	2
107 #define PRIV_PKTID_INFO_REQ	3
108 #define PRIV_PKTID_INFO_RESP	4
109 #define PRIV_PKTID_RESET_REQ	5
110 #define PRIV_PKTID_SET_DEF_MODE	6
111 
112 
113 #define ETX	0x03
114 #define DLE	0x10
115 #define ACK	0x06
116 #define NAK	0x15
117 
118 /* structure used to queue incoming packets */
119 struct garmin_packet {
120 	struct list_head  list;
121 	int               seq;
122 	/* the real size of the data array, always > 0 */
123 	int               size;
124 	__u8              data[1];
125 };
126 
127 /* structure used to keep the current state of the driver */
128 struct garmin_data {
129 	__u8   state;
130 	__u16  flags;
131 	__u8   mode;
132 	__u8   count;
133 	__u8   pkt_id;
134 	__u32  serial_num;
135 	struct timer_list timer;
136 	struct usb_serial_port *port;
137 	int    seq_counter;
138 	int    insize;
139 	int    outsize;
140 	__u8   inbuffer [GPS_IN_BUFSIZ];  /* tty -> usb */
141 	__u8   outbuffer[GPS_OUT_BUFSIZ]; /* usb -> tty */
142 	__u8   privpkt[4*6];
143 	spinlock_t lock;
144 	struct list_head pktlist;
145 };
146 
147 
148 #define STATE_NEW            0
149 #define STATE_INITIAL_DELAY  1
150 #define STATE_TIMEOUT        2
151 #define STATE_SESSION_REQ1   3
152 #define STATE_SESSION_REQ2   4
153 #define STATE_ACTIVE         5
154 
155 #define STATE_RESET	     8
156 #define STATE_DISCONNECTED   9
157 #define STATE_WAIT_TTY_ACK  10
158 #define STATE_GSP_WAIT_DATA 11
159 
160 #define MODE_NATIVE          0
161 #define MODE_GARMIN_SERIAL   1
162 
163 /* Flags used in garmin_data.flags: */
164 #define FLAGS_SESSION_REPLY_MASK  0x00C0
165 #define FLAGS_SESSION_REPLY1_SEEN 0x0080
166 #define FLAGS_SESSION_REPLY2_SEEN 0x0040
167 #define FLAGS_BULK_IN_ACTIVE      0x0020
168 #define FLAGS_BULK_IN_RESTART     0x0010
169 #define FLAGS_THROTTLED           0x0008
170 #define APP_REQ_SEEN              0x0004
171 #define APP_RESP_SEEN             0x0002
172 #define CLEAR_HALT_REQUIRED       0x0001
173 
174 #define FLAGS_QUEUING             0x0100
175 #define FLAGS_DROP_DATA           0x0800
176 
177 #define FLAGS_GSP_SKIP            0x1000
178 #define FLAGS_GSP_DLESEEN         0x2000
179 
180 
181 
182 
183 
184 
185 /* function prototypes */
186 static int gsp_next_packet(struct garmin_data *garmin_data_p);
187 static int garmin_write_bulk(struct usb_serial_port *port,
188 			     const unsigned char *buf, int count,
189 			     int dismiss_ack);
190 
191 /* some special packets to be send or received */
192 static unsigned char const GARMIN_START_SESSION_REQ[]
193 	= { 0, 0, 0, 0,  5, 0, 0, 0, 0, 0, 0, 0 };
194 static unsigned char const GARMIN_START_SESSION_REPLY[]
195 	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
196 static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
197 	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
198 static unsigned char const GARMIN_APP_LAYER_REPLY[]
199 	= { 0x14, 0, 0, 0 };
200 static unsigned char const GARMIN_START_PVT_REQ[]
201 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
202 static unsigned char const GARMIN_STOP_PVT_REQ[]
203 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
204 static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
205 	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
206 static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
207 	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
208 static unsigned char const PRIVATE_REQ[]
209 	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };
210 
211 
212 
213 static const struct usb_device_id id_table[] = {
214 	/* the same device id seems to be used by all
215 	   usb enabled GPS devices */
216 	{ USB_DEVICE(GARMIN_VENDOR_ID, 3) },
217 	{ }					/* Terminating entry */
218 };
219 MODULE_DEVICE_TABLE(usb, id_table);
220 
221 
222 static inline int getLayerId(const __u8 *usbPacket)
223 {
224 	return __le32_to_cpup((__le32 *)(usbPacket));
225 }
226 
227 static inline int getPacketId(const __u8 *usbPacket)
228 {
229 	return __le32_to_cpup((__le32 *)(usbPacket+4));
230 }
231 
232 static inline int getDataLength(const __u8 *usbPacket)
233 {
234 	return __le32_to_cpup((__le32 *)(usbPacket+8));
235 }
236 
237 
238 /*
239  * check if the usb-packet in buf contains an abort-transfer command.
240  * (if yes, all queued data will be dropped)
241  */
242 static inline int isAbortTrfCmnd(const unsigned char *buf)
243 {
244 	if (0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ,
245 					sizeof(GARMIN_STOP_TRANSFER_REQ)) ||
246 	    0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2,
247 					sizeof(GARMIN_STOP_TRANSFER_REQ_V2)))
248 		return 1;
249 	else
250 		return 0;
251 }
252 
253 
254 
255 static void send_to_tty(struct usb_serial_port *port,
256 			char *data, unsigned int actual_length)
257 {
258 	struct tty_struct *tty = tty_port_tty_get(&port->port);
259 
260 	if (tty && actual_length) {
261 		usb_serial_debug_data(&port->dev, __func__, actual_length, data);
262 		tty_insert_flip_string(tty, data, actual_length);
263 		tty_flip_buffer_push(tty);
264 	}
265 	tty_kref_put(tty);
266 }
267 
268 
269 /******************************************************************************
270  * packet queue handling
271  ******************************************************************************/
272 
273 /*
274  * queue a received (usb-)packet for later processing
275  */
276 static int pkt_add(struct garmin_data *garmin_data_p,
277 		   unsigned char *data, unsigned int data_length)
278 {
279 	int state = 0;
280 	int result = 0;
281 	unsigned long flags;
282 	struct garmin_packet *pkt;
283 
284 	/* process only packets containg data ... */
285 	if (data_length) {
286 		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
287 								GFP_ATOMIC);
288 		if (pkt == NULL) {
289 			dev_err(&garmin_data_p->port->dev, "out of memory\n");
290 			return 0;
291 		}
292 		pkt->size = data_length;
293 		memcpy(pkt->data, data, data_length);
294 
295 		spin_lock_irqsave(&garmin_data_p->lock, flags);
296 		garmin_data_p->flags |= FLAGS_QUEUING;
297 		result = list_empty(&garmin_data_p->pktlist);
298 		pkt->seq = garmin_data_p->seq_counter++;
299 		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
300 		state = garmin_data_p->state;
301 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
302 
303 		dev_dbg(&garmin_data_p->port->dev,
304 			"%s - added: pkt: %d - %d bytes\n", __func__,
305 			pkt->seq, data_length);
306 
307 		/* in serial mode, if someone is waiting for data from
308 		   the device, convert and send the next packet to tty. */
309 		if (result && (state == STATE_GSP_WAIT_DATA))
310 			gsp_next_packet(garmin_data_p);
311 	}
312 	return result;
313 }
314 
315 
316 /* get the next pending packet */
317 static struct garmin_packet *pkt_pop(struct garmin_data *garmin_data_p)
318 {
319 	unsigned long flags;
320 	struct garmin_packet *result = NULL;
321 
322 	spin_lock_irqsave(&garmin_data_p->lock, flags);
323 	if (!list_empty(&garmin_data_p->pktlist)) {
324 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
325 		list_del(&result->list);
326 	}
327 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
328 	return result;
329 }
330 
331 
332 /* free up all queued data */
333 static void pkt_clear(struct garmin_data *garmin_data_p)
334 {
335 	unsigned long flags;
336 	struct garmin_packet *result = NULL;
337 
338 	spin_lock_irqsave(&garmin_data_p->lock, flags);
339 	while (!list_empty(&garmin_data_p->pktlist)) {
340 		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
341 		list_del(&result->list);
342 		kfree(result);
343 	}
344 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
345 }
346 
347 
348 /******************************************************************************
349  * garmin serial protocol handling handling
350  ******************************************************************************/
351 
352 /* send an ack packet back to the tty */
353 static int gsp_send_ack(struct garmin_data *garmin_data_p, __u8 pkt_id)
354 {
355 	__u8 pkt[10];
356 	__u8 cksum = 0;
357 	__u8 *ptr = pkt;
358 	unsigned  l = 0;
359 
360 	dev_dbg(&garmin_data_p->port->dev, "%s - pkt-id: 0x%X.\n", __func__,
361 		0xFF & pkt_id);
362 
363 	*ptr++ = DLE;
364 	*ptr++ = ACK;
365 	cksum += ACK;
366 
367 	*ptr++ = 2;
368 	cksum += 2;
369 
370 	*ptr++ = pkt_id;
371 	cksum += pkt_id;
372 
373 	if (pkt_id == DLE)
374 		*ptr++ = DLE;
375 
376 	*ptr++ = 0;
377 	*ptr++ = 0xFF & (-cksum);
378 	*ptr++ = DLE;
379 	*ptr++ = ETX;
380 
381 	l = ptr-pkt;
382 
383 	send_to_tty(garmin_data_p->port, pkt, l);
384 	return 0;
385 }
386 
387 
388 
389 /*
390  * called for a complete packet received from tty layer
391  *
392  * the complete packet (pktid ... cksum) is in garmin_data_p->inbuf starting
393  * at GSP_INITIAL_OFFSET.
394  *
395  * count - number of bytes in the input buffer including space reserved for
396  *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet
397  *         (including pkt-id, data-length a. cksum)
398  */
399 static int gsp_rec_packet(struct garmin_data *garmin_data_p, int count)
400 {
401 	struct device *dev = &garmin_data_p->port->dev;
402 	unsigned long flags;
403 	const __u8 *recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
404 	__le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;
405 	int cksum = 0;
406 	int n = 0;
407 	int pktid = recpkt[0];
408 	int size = recpkt[1];
409 
410 	usb_serial_debug_data(&garmin_data_p->port->dev, __func__,
411 			      count-GSP_INITIAL_OFFSET, recpkt);
412 
413 	if (size != (count-GSP_INITIAL_OFFSET-3)) {
414 		dev_dbg(dev, "%s - invalid size, expected %d bytes, got %d\n",
415 			__func__, size, (count-GSP_INITIAL_OFFSET-3));
416 		return -EINVPKT;
417 	}
418 
419 	cksum += *recpkt++;
420 	cksum += *recpkt++;
421 
422 	/* sanity check, remove after test ... */
423 	if ((__u8 *)&(usbdata[3]) != recpkt) {
424 		dev_dbg(dev, "%s - ptr mismatch %p - %p\n", __func__,
425 			&(usbdata[4]), recpkt);
426 		return -EINVPKT;
427 	}
428 
429 	while (n < size) {
430 		cksum += *recpkt++;
431 		n++;
432 	}
433 
434 	if ((0xff & (cksum + *recpkt)) != 0) {
435 		dev_dbg(dev, "%s - invalid checksum, expected %02x, got %02x\n",
436 			__func__, 0xff & -cksum, 0xff & *recpkt);
437 		return -EINVPKT;
438 	}
439 
440 	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
441 	usbdata[1] = __cpu_to_le32(pktid);
442 	usbdata[2] = __cpu_to_le32(size);
443 
444 	garmin_write_bulk(garmin_data_p->port, garmin_data_p->inbuffer,
445 			   GARMIN_PKTHDR_LENGTH+size, 0);
446 
447 	/* if this was an abort-transfer command, flush all
448 	   queued data. */
449 	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
450 		spin_lock_irqsave(&garmin_data_p->lock, flags);
451 		garmin_data_p->flags |= FLAGS_DROP_DATA;
452 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
453 		pkt_clear(garmin_data_p);
454 	}
455 
456 	return count;
457 }
458 
459 
460 
461 /*
462  * Called for data received from tty
463  *
464  * buf contains the data read, it may span more than one packet or even
465  * incomplete packets
466  *
467  * input record should be a serial-record, but it may not be complete.
468  * Copy it into our local buffer, until an etx is seen (or an error
469  * occurs).
470  * Once the record is complete, convert into a usb packet and send it
471  * to the bulk pipe, send an ack back to the tty.
472  *
473  * If the input is an ack, just send the last queued packet to the
474  * tty layer.
475  *
476  * if the input is an abort command, drop all queued data.
477  */
478 
479 static int gsp_receive(struct garmin_data *garmin_data_p,
480 		       const unsigned char *buf, int count)
481 {
482 	struct device *dev = &garmin_data_p->port->dev;
483 	unsigned long flags;
484 	int offs = 0;
485 	int ack_or_nak_seen = 0;
486 	__u8 *dest;
487 	int size;
488 	/* dleSeen: set if last byte read was a DLE */
489 	int dleSeen;
490 	/* skip: if set, skip incoming data until possible start of
491 	 *       new packet
492 	 */
493 	int skip;
494 	__u8 data;
495 
496 	spin_lock_irqsave(&garmin_data_p->lock, flags);
497 	dest = garmin_data_p->inbuffer;
498 	size = garmin_data_p->insize;
499 	dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
500 	skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
501 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
502 
503 	/* dev_dbg(dev, "%s - dle=%d skip=%d size=%d count=%d\n",
504 		__func__, dleSeen, skip, size, count); */
505 
506 	if (size == 0)
507 		size = GSP_INITIAL_OFFSET;
508 
509 	while (offs < count) {
510 
511 		data = *(buf+offs);
512 		offs++;
513 
514 		if (data == DLE) {
515 			if (skip) { /* start of a new pkt */
516 				skip = 0;
517 				size = GSP_INITIAL_OFFSET;
518 				dleSeen = 1;
519 			} else if (dleSeen) {
520 				dest[size++] = data;
521 				dleSeen = 0;
522 			} else {
523 				dleSeen = 1;
524 			}
525 		} else if (data == ETX) {
526 			if (dleSeen) {
527 				/* packet complete */
528 
529 				data = dest[GSP_INITIAL_OFFSET];
530 
531 				if (data == ACK) {
532 					ack_or_nak_seen = ACK;
533 					dev_dbg(dev, "ACK packet complete.\n");
534 				} else if (data == NAK) {
535 					ack_or_nak_seen = NAK;
536 					dev_dbg(dev, "NAK packet complete.\n");
537 				} else {
538 					dev_dbg(dev, "packet complete - id=0x%X.\n",
539 						0xFF & data);
540 					gsp_rec_packet(garmin_data_p, size);
541 				}
542 
543 				skip = 1;
544 				size = GSP_INITIAL_OFFSET;
545 				dleSeen = 0;
546 			} else {
547 				dest[size++] = data;
548 			}
549 		} else if (!skip) {
550 
551 			if (dleSeen) {
552 				size = GSP_INITIAL_OFFSET;
553 				dleSeen = 0;
554 			}
555 
556 			dest[size++] = data;
557 		}
558 
559 		if (size >= GPS_IN_BUFSIZ) {
560 			dev_dbg(dev, "%s - packet too large.\n", __func__);
561 			skip = 1;
562 			size = GSP_INITIAL_OFFSET;
563 			dleSeen = 0;
564 		}
565 	}
566 
567 	spin_lock_irqsave(&garmin_data_p->lock, flags);
568 
569 	garmin_data_p->insize = size;
570 
571 	/* copy flags back to structure */
572 	if (skip)
573 		garmin_data_p->flags |= FLAGS_GSP_SKIP;
574 	else
575 		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;
576 
577 	if (dleSeen)
578 		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
579 	else
580 		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;
581 
582 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
583 
584 	if (ack_or_nak_seen) {
585 		if (gsp_next_packet(garmin_data_p) > 0)
586 			garmin_data_p->state = STATE_ACTIVE;
587 		else
588 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
589 	}
590 	return count;
591 }
592 
593 
594 
595 /*
596  * Sends a usb packet to the tty
597  *
598  * Assumes, that all packages and at an usb-packet boundary.
599  *
600  * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
601  */
602 static int gsp_send(struct garmin_data *garmin_data_p,
603 		    const unsigned char *buf, int count)
604 {
605 	struct device *dev = &garmin_data_p->port->dev;
606 	const unsigned char *src;
607 	unsigned char *dst;
608 	int pktid = 0;
609 	int datalen = 0;
610 	int cksum = 0;
611 	int i = 0;
612 	int k;
613 
614 	dev_dbg(dev, "%s - state %d - %d bytes.\n", __func__,
615 		garmin_data_p->state, count);
616 
617 	k = garmin_data_p->outsize;
618 	if ((k+count) > GPS_OUT_BUFSIZ) {
619 		dev_dbg(dev, "packet too large\n");
620 		garmin_data_p->outsize = 0;
621 		return -4;
622 	}
623 
624 	memcpy(garmin_data_p->outbuffer+k, buf, count);
625 	k += count;
626 	garmin_data_p->outsize = k;
627 
628 	if (k >= GARMIN_PKTHDR_LENGTH) {
629 		pktid  = getPacketId(garmin_data_p->outbuffer);
630 		datalen = getDataLength(garmin_data_p->outbuffer);
631 		i = GARMIN_PKTHDR_LENGTH + datalen;
632 		if (k < i)
633 			return 0;
634 	} else {
635 		return 0;
636 	}
637 
638 	dev_dbg(dev, "%s - %d bytes in buffer, %d bytes in pkt.\n", __func__, k, i);
639 
640 	/* garmin_data_p->outbuffer now contains a complete packet */
641 
642 	usb_serial_debug_data(&garmin_data_p->port->dev, __func__, k,
643 			      garmin_data_p->outbuffer);
644 
645 	garmin_data_p->outsize = 0;
646 
647 	if (GARMIN_LAYERID_APPL != getLayerId(garmin_data_p->outbuffer)) {
648 		dev_dbg(dev, "not an application packet (%d)\n",
649 				getLayerId(garmin_data_p->outbuffer));
650 		return -1;
651 	}
652 
653 	if (pktid > 255) {
654 		dev_dbg(dev, "packet-id %d too large\n", pktid);
655 		return -2;
656 	}
657 
658 	if (datalen > 255) {
659 		dev_dbg(dev, "packet-size %d too large\n", datalen);
660 		return -3;
661 	}
662 
663 	/* the serial protocol should be able to handle this packet */
664 
665 	k = 0;
666 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
667 	for (i = 0; i < datalen; i++) {
668 		if (*src++ == DLE)
669 			k++;
670 	}
671 
672 	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
673 	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
674 		/* can't add stuffing DLEs in place, move data to end
675 		   of buffer ... */
676 		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
677 		memcpy(dst, src, datalen);
678 		src = dst;
679 	}
680 
681 	dst = garmin_data_p->outbuffer;
682 
683 	*dst++ = DLE;
684 	*dst++ = pktid;
685 	cksum += pktid;
686 	*dst++ = datalen;
687 	cksum += datalen;
688 	if (datalen == DLE)
689 		*dst++ = DLE;
690 
691 	for (i = 0; i < datalen; i++) {
692 		__u8 c = *src++;
693 		*dst++ = c;
694 		cksum += c;
695 		if (c == DLE)
696 			*dst++ = DLE;
697 	}
698 
699 	cksum = 0xFF & -cksum;
700 	*dst++ = cksum;
701 	if (cksum == DLE)
702 		*dst++ = DLE;
703 	*dst++ = DLE;
704 	*dst++ = ETX;
705 
706 	i = dst-garmin_data_p->outbuffer;
707 
708 	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);
709 
710 	garmin_data_p->pkt_id = pktid;
711 	garmin_data_p->state  = STATE_WAIT_TTY_ACK;
712 
713 	return i;
714 }
715 
716 
717 /*
718  * Process the next pending data packet - if there is one
719  */
720 static int gsp_next_packet(struct garmin_data *garmin_data_p)
721 {
722 	int result = 0;
723 	struct garmin_packet *pkt = NULL;
724 
725 	while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
726 		dev_dbg(&garmin_data_p->port->dev, "%s - next pkt: %d\n", __func__, pkt->seq);
727 		result = gsp_send(garmin_data_p, pkt->data, pkt->size);
728 		if (result > 0) {
729 			kfree(pkt);
730 			return result;
731 		}
732 		kfree(pkt);
733 	}
734 	return result;
735 }
736 
737 
738 
739 /******************************************************************************
740  * garmin native mode
741  ******************************************************************************/
742 
743 
744 /*
745  * Called for data received from tty
746  *
747  * The input data is expected to be in garmin usb-packet format.
748  *
749  * buf contains the data read, it may span more than one packet
750  * or even incomplete packets
751  */
752 static int nat_receive(struct garmin_data *garmin_data_p,
753 		       const unsigned char *buf, int count)
754 {
755 	unsigned long flags;
756 	__u8 *dest;
757 	int offs = 0;
758 	int result = count;
759 	int len;
760 
761 	while (offs < count) {
762 		/* if buffer contains header, copy rest of data */
763 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
764 			len = GARMIN_PKTHDR_LENGTH
765 			      +getDataLength(garmin_data_p->inbuffer);
766 		else
767 			len = GARMIN_PKTHDR_LENGTH;
768 
769 		if (len >= GPS_IN_BUFSIZ) {
770 			/* seems to be an invalid packet, ignore rest
771 			   of input */
772 			dev_dbg(&garmin_data_p->port->dev,
773 				"%s - packet size too large: %d\n",
774 				__func__, len);
775 			garmin_data_p->insize = 0;
776 			count = 0;
777 			result = -EINVPKT;
778 		} else {
779 			len -= garmin_data_p->insize;
780 			if (len > (count-offs))
781 				len = (count-offs);
782 			if (len > 0) {
783 				dest = garmin_data_p->inbuffer
784 						+ garmin_data_p->insize;
785 				memcpy(dest, buf+offs, len);
786 				garmin_data_p->insize += len;
787 				offs += len;
788 			}
789 		}
790 
791 		/* do we have a complete packet ? */
792 		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
793 			len = GARMIN_PKTHDR_LENGTH+
794 			   getDataLength(garmin_data_p->inbuffer);
795 			if (garmin_data_p->insize >= len) {
796 				garmin_write_bulk(garmin_data_p->port,
797 						   garmin_data_p->inbuffer,
798 						   len, 0);
799 				garmin_data_p->insize = 0;
800 
801 				/* if this was an abort-transfer command,
802 				   flush all queued data. */
803 				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
804 					spin_lock_irqsave(&garmin_data_p->lock,
805 									flags);
806 					garmin_data_p->flags |= FLAGS_DROP_DATA;
807 					spin_unlock_irqrestore(
808 						&garmin_data_p->lock, flags);
809 					pkt_clear(garmin_data_p);
810 				}
811 			}
812 		}
813 	}
814 	return result;
815 }
816 
817 
818 /******************************************************************************
819  * private packets
820  ******************************************************************************/
821 
822 static void priv_status_resp(struct usb_serial_port *port)
823 {
824 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
825 	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;
826 
827 	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
828 	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
829 	pkt[2] = __cpu_to_le32(12);
830 	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
831 	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
832 	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);
833 
834 	send_to_tty(port, (__u8 *)pkt, 6 * 4);
835 }
836 
837 
838 /******************************************************************************
839  * Garmin specific driver functions
840  ******************************************************************************/
841 
842 static int process_resetdev_request(struct usb_serial_port *port)
843 {
844 	unsigned long flags;
845 	int status;
846 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
847 
848 	spin_lock_irqsave(&garmin_data_p->lock, flags);
849 	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
850 	garmin_data_p->state = STATE_RESET;
851 	garmin_data_p->serial_num = 0;
852 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
853 
854 	usb_kill_urb(port->interrupt_in_urb);
855 	dev_dbg(&port->dev, "%s - usb_reset_device\n", __func__);
856 	status = usb_reset_device(port->serial->dev);
857 	if (status)
858 		dev_dbg(&port->dev, "%s - usb_reset_device failed: %d\n",
859 			__func__, status);
860 	return status;
861 }
862 
863 
864 
865 /*
866  * clear all cached data
867  */
868 static int garmin_clear(struct garmin_data *garmin_data_p)
869 {
870 	unsigned long flags;
871 	int status = 0;
872 
873 	/* flush all queued data */
874 	pkt_clear(garmin_data_p);
875 
876 	spin_lock_irqsave(&garmin_data_p->lock, flags);
877 	garmin_data_p->insize = 0;
878 	garmin_data_p->outsize = 0;
879 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
880 
881 	return status;
882 }
883 
884 
885 static int garmin_init_session(struct usb_serial_port *port)
886 {
887 	struct usb_serial *serial = port->serial;
888 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
889 	int status = 0;
890 	int i = 0;
891 
892 	if (status == 0) {
893 		usb_kill_urb(port->interrupt_in_urb);
894 
895 		dev_dbg(&serial->dev->dev, "%s - adding interrupt input\n", __func__);
896 		status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
897 		if (status)
898 			dev_err(&serial->dev->dev,
899 			  "%s - failed submitting interrupt urb, error %d\n",
900 							__func__, status);
901 	}
902 
903 	/*
904 	 * using the initialization method from gpsbabel. See comments in
905 	 * gpsbabel/jeeps/gpslibusb.c gusb_reset_toggles()
906 	 */
907 	if (status == 0) {
908 		dev_dbg(&serial->dev->dev, "%s - starting session ...\n", __func__);
909 		garmin_data_p->state = STATE_ACTIVE;
910 
911 		for (i = 0; i < 3; i++) {
912 			status = garmin_write_bulk(port,
913 					GARMIN_START_SESSION_REQ,
914 					sizeof(GARMIN_START_SESSION_REQ), 0);
915 
916 			if (status < 0)
917 				break;
918 		}
919 
920 		if (status > 0)
921 			status = 0;
922 	}
923 
924 	return status;
925 }
926 
927 
928 
929 static int garmin_open(struct tty_struct *tty, struct usb_serial_port *port)
930 {
931 	unsigned long flags;
932 	int status = 0;
933 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
934 
935 	spin_lock_irqsave(&garmin_data_p->lock, flags);
936 	garmin_data_p->mode  = initial_mode;
937 	garmin_data_p->count = 0;
938 	garmin_data_p->flags &= FLAGS_SESSION_REPLY1_SEEN;
939 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
940 
941 	/* shutdown any bulk reads that might be going on */
942 	usb_kill_urb(port->write_urb);
943 	usb_kill_urb(port->read_urb);
944 
945 	if (garmin_data_p->state == STATE_RESET)
946 		status = garmin_init_session(port);
947 
948 	garmin_data_p->state = STATE_ACTIVE;
949 	return status;
950 }
951 
952 
953 static void garmin_close(struct usb_serial_port *port)
954 {
955 	struct usb_serial *serial = port->serial;
956 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
957 
958 	dev_dbg(&port->dev, "%s - port %d - mode=%d state=%d flags=0x%X\n",
959 		__func__, port->number, garmin_data_p->mode,
960 		garmin_data_p->state, garmin_data_p->flags);
961 
962 	if (!serial)
963 		return;
964 
965 	mutex_lock(&port->serial->disc_mutex);
966 
967 	if (!port->serial->disconnected)
968 		garmin_clear(garmin_data_p);
969 
970 	/* shutdown our urbs */
971 	usb_kill_urb(port->read_urb);
972 	usb_kill_urb(port->write_urb);
973 
974 	/* keep reset state so we know that we must start a new session */
975 	if (garmin_data_p->state != STATE_RESET)
976 		garmin_data_p->state = STATE_DISCONNECTED;
977 
978 	mutex_unlock(&port->serial->disc_mutex);
979 }
980 
981 
982 static void garmin_write_bulk_callback(struct urb *urb)
983 {
984 	struct usb_serial_port *port = urb->context;
985 
986 	if (port) {
987 		struct garmin_data *garmin_data_p =
988 					usb_get_serial_port_data(port);
989 
990 		if (GARMIN_LAYERID_APPL == getLayerId(urb->transfer_buffer)) {
991 
992 			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
993 				gsp_send_ack(garmin_data_p,
994 					((__u8 *)urb->transfer_buffer)[4]);
995 			}
996 		}
997 		usb_serial_port_softint(port);
998 	}
999 
1000 	/* Ignore errors that resulted from garmin_write_bulk with
1001 	   dismiss_ack = 1 */
1002 
1003 	/* free up the transfer buffer, as usb_free_urb() does not do this */
1004 	kfree(urb->transfer_buffer);
1005 }
1006 
1007 
1008 static int garmin_write_bulk(struct usb_serial_port *port,
1009 			      const unsigned char *buf, int count,
1010 			      int dismiss_ack)
1011 {
1012 	unsigned long flags;
1013 	struct usb_serial *serial = port->serial;
1014 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1015 	struct urb *urb;
1016 	unsigned char *buffer;
1017 	int status;
1018 
1019 	spin_lock_irqsave(&garmin_data_p->lock, flags);
1020 	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
1021 	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1022 
1023 	buffer = kmalloc(count, GFP_ATOMIC);
1024 	if (!buffer) {
1025 		dev_err(&port->dev, "out of memory\n");
1026 		return -ENOMEM;
1027 	}
1028 
1029 	urb = usb_alloc_urb(0, GFP_ATOMIC);
1030 	if (!urb) {
1031 		dev_err(&port->dev, "no more free urbs\n");
1032 		kfree(buffer);
1033 		return -ENOMEM;
1034 	}
1035 
1036 	memcpy(buffer, buf, count);
1037 
1038 	usb_serial_debug_data(&port->dev, __func__, count, buffer);
1039 
1040 	usb_fill_bulk_urb(urb, serial->dev,
1041 				usb_sndbulkpipe(serial->dev,
1042 					port->bulk_out_endpointAddress),
1043 				buffer, count,
1044 				garmin_write_bulk_callback,
1045 				dismiss_ack ? NULL : port);
1046 	urb->transfer_flags |= URB_ZERO_PACKET;
1047 
1048 	if (GARMIN_LAYERID_APPL == getLayerId(buffer)) {
1049 
1050 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1051 		garmin_data_p->flags |= APP_REQ_SEEN;
1052 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1053 
1054 		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
1055 			pkt_clear(garmin_data_p);
1056 			garmin_data_p->state = STATE_GSP_WAIT_DATA;
1057 		}
1058 	}
1059 
1060 	/* send it down the pipe */
1061 	status = usb_submit_urb(urb, GFP_ATOMIC);
1062 	if (status) {
1063 		dev_err(&port->dev,
1064 		   "%s - usb_submit_urb(write bulk) failed with status = %d\n",
1065 				__func__, status);
1066 		count = status;
1067 	}
1068 
1069 	/* we are done with this urb, so let the host driver
1070 	 * really free it when it is finished with it */
1071 	usb_free_urb(urb);
1072 
1073 	return count;
1074 }
1075 
1076 static int garmin_write(struct tty_struct *tty, struct usb_serial_port *port,
1077 					 const unsigned char *buf, int count)
1078 {
1079 	struct device *dev = &port->dev;
1080 	int pktid, pktsiz, len;
1081 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1082 	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;
1083 
1084 	usb_serial_debug_data(dev, __func__, count, buf);
1085 
1086 	if (garmin_data_p->state == STATE_RESET)
1087 		return -EIO;
1088 
1089 	/* check for our private packets */
1090 	if (count >= GARMIN_PKTHDR_LENGTH) {
1091 		len = PRIVPKTSIZ;
1092 		if (count < len)
1093 			len = count;
1094 
1095 		memcpy(garmin_data_p->privpkt, buf, len);
1096 
1097 		pktsiz = getDataLength(garmin_data_p->privpkt);
1098 		pktid  = getPacketId(garmin_data_p->privpkt);
1099 
1100 		if (count == (GARMIN_PKTHDR_LENGTH+pktsiz)
1101 		    && GARMIN_LAYERID_PRIVATE ==
1102 				getLayerId(garmin_data_p->privpkt)) {
1103 
1104 			dev_dbg(dev, "%s - processing private request %d\n",
1105 				__func__, pktid);
1106 
1107 			/* drop all unfinished transfers */
1108 			garmin_clear(garmin_data_p);
1109 
1110 			switch (pktid) {
1111 
1112 			case PRIV_PKTID_SET_DEBUG:
1113 				if (pktsiz != 4)
1114 					return -EINVPKT;
1115 				debug = __le32_to_cpu(privpkt[3]);
1116 				dev_dbg(dev, "%s - debug level set to 0x%X\n",
1117 					__func__, debug);
1118 				break;
1119 
1120 			case PRIV_PKTID_SET_MODE:
1121 				if (pktsiz != 4)
1122 					return -EINVPKT;
1123 				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
1124 				dev_dbg(dev, "%s - mode set to %d\n",
1125 					__func__, garmin_data_p->mode);
1126 				break;
1127 
1128 			case PRIV_PKTID_INFO_REQ:
1129 				priv_status_resp(port);
1130 				break;
1131 
1132 			case PRIV_PKTID_RESET_REQ:
1133 				process_resetdev_request(port);
1134 				break;
1135 
1136 			case PRIV_PKTID_SET_DEF_MODE:
1137 				if (pktsiz != 4)
1138 					return -EINVPKT;
1139 				initial_mode = __le32_to_cpu(privpkt[3]);
1140 				dev_dbg(dev, "%s - initial_mode set to %d\n",
1141 					__func__,
1142 					garmin_data_p->mode);
1143 				break;
1144 			}
1145 			return count;
1146 		}
1147 	}
1148 
1149 	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1150 		return gsp_receive(garmin_data_p, buf, count);
1151 	} else {	/* MODE_NATIVE */
1152 		return nat_receive(garmin_data_p, buf, count);
1153 	}
1154 }
1155 
1156 
1157 static int garmin_write_room(struct tty_struct *tty)
1158 {
1159 	struct usb_serial_port *port = tty->driver_data;
1160 	/*
1161 	 * Report back the bytes currently available in the output buffer.
1162 	 */
1163 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1164 	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
1165 }
1166 
1167 
1168 static void garmin_read_process(struct garmin_data *garmin_data_p,
1169 				 unsigned char *data, unsigned data_length,
1170 				 int bulk_data)
1171 {
1172 	unsigned long flags;
1173 
1174 	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
1175 		/* abort-transfer cmd is actice */
1176 		dev_dbg(&garmin_data_p->port->dev, "%s - pkt dropped\n", __func__);
1177 	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
1178 		garmin_data_p->state != STATE_RESET) {
1179 
1180 		/* if throttling is active or postprecessing is required
1181 		   put the received data in the input queue, otherwise
1182 		   send it directly to the tty port */
1183 		if (garmin_data_p->flags & FLAGS_QUEUING) {
1184 			pkt_add(garmin_data_p, data, data_length);
1185 		} else if (bulk_data ||
1186 			   getLayerId(data) == GARMIN_LAYERID_APPL) {
1187 
1188 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1189 			garmin_data_p->flags |= APP_RESP_SEEN;
1190 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1191 
1192 			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1193 				pkt_add(garmin_data_p, data, data_length);
1194 			} else {
1195 				send_to_tty(garmin_data_p->port, data,
1196 						data_length);
1197 			}
1198 		}
1199 		/* ignore system layer packets ... */
1200 	}
1201 }
1202 
1203 
1204 static void garmin_read_bulk_callback(struct urb *urb)
1205 {
1206 	unsigned long flags;
1207 	struct usb_serial_port *port = urb->context;
1208 	struct usb_serial *serial =  port->serial;
1209 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1210 	unsigned char *data = urb->transfer_buffer;
1211 	int status = urb->status;
1212 	int retval;
1213 
1214 	if (!serial) {
1215 		dev_dbg(&urb->dev->dev, "%s - bad serial pointer, exiting\n", __func__);
1216 		return;
1217 	}
1218 
1219 	if (status) {
1220 		dev_dbg(&urb->dev->dev, "%s - nonzero read bulk status received: %d\n",
1221 			__func__, status);
1222 		return;
1223 	}
1224 
1225 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
1226 
1227 	garmin_read_process(garmin_data_p, data, urb->actual_length, 1);
1228 
1229 	if (urb->actual_length == 0 &&
1230 			0 != (garmin_data_p->flags & FLAGS_BULK_IN_RESTART)) {
1231 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1232 		garmin_data_p->flags &= ~FLAGS_BULK_IN_RESTART;
1233 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1234 		retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1235 		if (retval)
1236 			dev_err(&port->dev,
1237 				"%s - failed resubmitting read urb, error %d\n",
1238 				__func__, retval);
1239 	} else if (urb->actual_length > 0) {
1240 		/* Continue trying to read until nothing more is received  */
1241 		if (0 == (garmin_data_p->flags & FLAGS_THROTTLED)) {
1242 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1243 			if (retval)
1244 				dev_err(&port->dev,
1245 					"%s - failed resubmitting read urb, error %d\n",
1246 					__func__, retval);
1247 		}
1248 	} else {
1249 		dev_dbg(&port->dev, "%s - end of bulk data\n", __func__);
1250 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1251 		garmin_data_p->flags &= ~FLAGS_BULK_IN_ACTIVE;
1252 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1253 	}
1254 }
1255 
1256 
1257 static void garmin_read_int_callback(struct urb *urb)
1258 {
1259 	unsigned long flags;
1260 	int retval;
1261 	struct usb_serial_port *port = urb->context;
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 
1266 	switch (status) {
1267 	case 0:
1268 		/* success */
1269 		break;
1270 	case -ECONNRESET:
1271 	case -ENOENT:
1272 	case -ESHUTDOWN:
1273 		/* this urb is terminated, clean up */
1274 		dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
1275 			__func__, status);
1276 		return;
1277 	default:
1278 		dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
1279 			__func__, status);
1280 		return;
1281 	}
1282 
1283 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
1284 			      urb->transfer_buffer);
1285 
1286 	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
1287 	    0 == memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
1288 				sizeof(GARMIN_BULK_IN_AVAIL_REPLY))) {
1289 
1290 		dev_dbg(&port->dev, "%s - bulk data available.\n", __func__);
1291 
1292 		if (0 == (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1293 
1294 			/* bulk data available */
1295 			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1296 			if (retval) {
1297 				dev_err(&port->dev,
1298 				 "%s - failed submitting read urb, error %d\n",
1299 							__func__, retval);
1300 			} else {
1301 				spin_lock_irqsave(&garmin_data_p->lock, flags);
1302 				garmin_data_p->flags |= FLAGS_BULK_IN_ACTIVE;
1303 				spin_unlock_irqrestore(&garmin_data_p->lock,
1304 									flags);
1305 			}
1306 		} else {
1307 			/* bulk-in transfer still active */
1308 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1309 			garmin_data_p->flags |= FLAGS_BULK_IN_RESTART;
1310 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1311 		}
1312 
1313 	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
1314 			 && 0 == memcmp(data, GARMIN_START_SESSION_REPLY,
1315 					sizeof(GARMIN_START_SESSION_REPLY))) {
1316 
1317 		spin_lock_irqsave(&garmin_data_p->lock, flags);
1318 		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
1319 		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1320 
1321 		/* save the serial number */
1322 		garmin_data_p->serial_num = __le32_to_cpup(
1323 					(__le32 *)(data+GARMIN_PKTHDR_LENGTH));
1324 
1325 		dev_dbg(&port->dev, "%s - start-of-session reply seen - serial %u.\n",
1326 			__func__, garmin_data_p->serial_num);
1327 	}
1328 
1329 	garmin_read_process(garmin_data_p, data, urb->actual_length, 0);
1330 
1331 	retval = usb_submit_urb(urb, GFP_ATOMIC);
1332 	if (retval)
1333 		dev_err(&urb->dev->dev,
1334 			"%s - Error %d submitting interrupt urb\n",
1335 			__func__, retval);
1336 }
1337 
1338 
1339 /*
1340  * Sends the next queued packt to the tty port (garmin native mode only)
1341  * and then sets a timer to call itself again until all queued data
1342  * is sent.
1343  */
1344 static int garmin_flush_queue(struct garmin_data *garmin_data_p)
1345 {
1346 	unsigned long flags;
1347 	struct garmin_packet *pkt;
1348 
1349 	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1350 		pkt = pkt_pop(garmin_data_p);
1351 		if (pkt != NULL) {
1352 			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
1353 			kfree(pkt);
1354 			mod_timer(&garmin_data_p->timer, (1)+jiffies);
1355 
1356 		} else {
1357 			spin_lock_irqsave(&garmin_data_p->lock, flags);
1358 			garmin_data_p->flags &= ~FLAGS_QUEUING;
1359 			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1360 		}
1361 	}
1362 	return 0;
1363 }
1364 
1365 
1366 static void garmin_throttle(struct tty_struct *tty)
1367 {
1368 	struct usb_serial_port *port = tty->driver_data;
1369 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1370 
1371 	/* set flag, data received will be put into a queue
1372 	   for later processing */
1373 	spin_lock_irq(&garmin_data_p->lock);
1374 	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
1375 	spin_unlock_irq(&garmin_data_p->lock);
1376 }
1377 
1378 
1379 static void garmin_unthrottle(struct tty_struct *tty)
1380 {
1381 	struct usb_serial_port *port = tty->driver_data;
1382 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1383 	int status;
1384 
1385 	spin_lock_irq(&garmin_data_p->lock);
1386 	garmin_data_p->flags &= ~FLAGS_THROTTLED;
1387 	spin_unlock_irq(&garmin_data_p->lock);
1388 
1389 	/* in native mode send queued data to tty, in
1390 	   serial mode nothing needs to be done here */
1391 	if (garmin_data_p->mode == MODE_NATIVE)
1392 		garmin_flush_queue(garmin_data_p);
1393 
1394 	if (0 != (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
1395 		status = usb_submit_urb(port->read_urb, GFP_KERNEL);
1396 		if (status)
1397 			dev_err(&port->dev,
1398 				"%s - failed resubmitting read urb, error %d\n",
1399 				__func__, status);
1400 	}
1401 }
1402 
1403 /*
1404  * The timer is currently only used to send queued packets to
1405  * the tty in cases where the protocol provides no own handshaking
1406  * to initiate the transfer.
1407  */
1408 static void timeout_handler(unsigned long data)
1409 {
1410 	struct garmin_data *garmin_data_p = (struct garmin_data *) data;
1411 
1412 	/* send the next queued packet to the tty port */
1413 	if (garmin_data_p->mode == MODE_NATIVE)
1414 		if (garmin_data_p->flags & FLAGS_QUEUING)
1415 			garmin_flush_queue(garmin_data_p);
1416 }
1417 
1418 
1419 
1420 static int garmin_attach(struct usb_serial *serial)
1421 {
1422 	int status = 0;
1423 	struct usb_serial_port *port = serial->port[0];
1424 	struct garmin_data *garmin_data_p = NULL;
1425 
1426 	garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
1427 	if (garmin_data_p == NULL) {
1428 		dev_err(&port->dev, "%s - Out of memory\n", __func__);
1429 		return -ENOMEM;
1430 	}
1431 	init_timer(&garmin_data_p->timer);
1432 	spin_lock_init(&garmin_data_p->lock);
1433 	INIT_LIST_HEAD(&garmin_data_p->pktlist);
1434 	/* garmin_data_p->timer.expires = jiffies + session_timeout; */
1435 	garmin_data_p->timer.data = (unsigned long)garmin_data_p;
1436 	garmin_data_p->timer.function = timeout_handler;
1437 	garmin_data_p->port = port;
1438 	garmin_data_p->state = 0;
1439 	garmin_data_p->flags = 0;
1440 	garmin_data_p->count = 0;
1441 	usb_set_serial_port_data(port, garmin_data_p);
1442 
1443 	status = garmin_init_session(port);
1444 
1445 	return status;
1446 }
1447 
1448 
1449 static void garmin_disconnect(struct usb_serial *serial)
1450 {
1451 	struct usb_serial_port *port = serial->port[0];
1452 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1453 
1454 	usb_kill_urb(port->interrupt_in_urb);
1455 	del_timer_sync(&garmin_data_p->timer);
1456 }
1457 
1458 
1459 static void garmin_release(struct usb_serial *serial)
1460 {
1461 	struct usb_serial_port *port = serial->port[0];
1462 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1463 
1464 	kfree(garmin_data_p);
1465 }
1466 
1467 
1468 /* All of the device info needed */
1469 static struct usb_serial_driver garmin_device = {
1470 	.driver = {
1471 		.owner       = THIS_MODULE,
1472 		.name        = "garmin_gps",
1473 	},
1474 	.description         = "Garmin GPS usb/tty",
1475 	.id_table            = id_table,
1476 	.num_ports           = 1,
1477 	.open                = garmin_open,
1478 	.close               = garmin_close,
1479 	.throttle            = garmin_throttle,
1480 	.unthrottle          = garmin_unthrottle,
1481 	.attach              = garmin_attach,
1482 	.disconnect          = garmin_disconnect,
1483 	.release             = garmin_release,
1484 	.write               = garmin_write,
1485 	.write_room          = garmin_write_room,
1486 	.write_bulk_callback = garmin_write_bulk_callback,
1487 	.read_bulk_callback  = garmin_read_bulk_callback,
1488 	.read_int_callback   = garmin_read_int_callback,
1489 };
1490 
1491 static struct usb_serial_driver * const serial_drivers[] = {
1492 	&garmin_device, NULL
1493 };
1494 
1495 module_usb_serial_driver(serial_drivers, id_table);
1496 
1497 MODULE_AUTHOR(DRIVER_AUTHOR);
1498 MODULE_DESCRIPTION(DRIVER_DESC);
1499 MODULE_LICENSE("GPL");
1500 
1501 module_param(debug, bool, S_IWUSR | S_IRUGO);
1502 MODULE_PARM_DESC(debug, "Debug enabled or not");
1503 module_param(initial_mode, int, S_IRUGO);
1504 MODULE_PARM_DESC(initial_mode, "Initial mode");
1505