1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Garmin GPS driver
   4 *
   5 * Copyright (C) 2006-2011 Hermann Kneissel herkne@gmx.de
   6 *
   7 * The latest version of the driver can be found at
   8 * http://sourceforge.net/projects/garmin-gps/
   9 *
  10 * This driver has been derived from v2.1 of the visor driver.
  11 */
  12
  13#include <linux/kernel.h>
  14#include <linux/errno.h>
  15#include <linux/slab.h>
  16#include <linux/timer.h>
  17#include <linux/tty.h>
  18#include <linux/tty_driver.h>
  19#include <linux/tty_flip.h>
  20#include <linux/module.h>
  21#include <linux/spinlock.h>
  22#include <linux/uaccess.h>
  23#include <linux/atomic.h>
  24#include <linux/usb.h>
  25#include <linux/usb/serial.h>
  26
  27/* the mode to be set when the port ist opened */
  28static int initial_mode = 1;
  29
  30#define GARMIN_VENDOR_ID             0x091E
  31
  32/*
  33 * Version Information
  34 */
  35
  36#define VERSION_MAJOR	0
  37#define VERSION_MINOR	36
  38
  39#define _STR(s) #s
  40#define _DRIVER_VERSION(a, b) "v" _STR(a) "." _STR(b)
  41#define DRIVER_VERSION _DRIVER_VERSION(VERSION_MAJOR, VERSION_MINOR)
  42#define DRIVER_AUTHOR "hermann kneissel"
  43#define DRIVER_DESC "garmin gps driver"
  44
  45/* error codes returned by the driver */
  46#define EINVPKT	1000	/* invalid packet structure */
  47
  48
  49/* size of the header of a packet using the usb protocol */
  50#define GARMIN_PKTHDR_LENGTH	12
  51
  52/* max. possible size of a packet using the serial protocol */
  53#define MAX_SERIAL_PKT_SIZ (3 + 255 + 3)
  54
  55/*  max. possible size of a packet with worst case stuffing */
  56#define MAX_SERIAL_PKT_SIZ_STUFFED (MAX_SERIAL_PKT_SIZ + 256)
  57
  58/* size of a buffer able to hold a complete (no stuffing) packet
  59 * (the document protocol does not contain packets with a larger
  60 *  size, but in theory a packet may be 64k+12 bytes - if in
  61 *  later protocol versions larger packet sizes occur, this value
  62 *  should be increased accordingly, so the input buffer is always
  63 *  large enough the store a complete packet inclusive header) */
  64#define GPS_IN_BUFSIZ  (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ)
  65
  66/* size of a buffer able to hold a complete (incl. stuffing) packet */
  67#define GPS_OUT_BUFSIZ (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ_STUFFED)
  68
  69/* where to place the packet id of a serial packet, so we can
  70 * prepend the usb-packet header without the need to move the
  71 * packets data */
  72#define GSP_INITIAL_OFFSET (GARMIN_PKTHDR_LENGTH-2)
  73
  74/* max. size of incoming private packets (header+1 param) */
  75#define PRIVPKTSIZ (GARMIN_PKTHDR_LENGTH+4)
  76
  77#define GARMIN_LAYERID_TRANSPORT  0
  78#define GARMIN_LAYERID_APPL      20
  79/* our own layer-id to use for some control mechanisms */
  80#define GARMIN_LAYERID_PRIVATE	0x01106E4B
  81
  82#define GARMIN_PKTID_PVT_DATA	51
  83#define GARMIN_PKTID_L001_COMMAND_DATA 10
  84
  85#define CMND_ABORT_TRANSFER 0
  86
  87/* packet ids used in private layer */
  88#define PRIV_PKTID_SET_DEBUG	1
  89#define PRIV_PKTID_SET_MODE	2
  90#define PRIV_PKTID_INFO_REQ	3
  91#define PRIV_PKTID_INFO_RESP	4
  92#define PRIV_PKTID_RESET_REQ	5
  93#define PRIV_PKTID_SET_DEF_MODE	6
  94
  95
  96#define ETX	0x03
  97#define DLE	0x10
  98#define ACK	0x06
  99#define NAK	0x15
 100
 101/* structure used to queue incoming packets */
 102struct garmin_packet {
 103	struct list_head  list;
 104	int               seq;
 105	/* the real size of the data array, always > 0 */
 106	int               size;
 107	__u8              data[];
 108};
 109
 110/* structure used to keep the current state of the driver */
 111struct garmin_data {
 112	__u8   state;
 113	__u16  flags;
 114	__u8   mode;
 115	__u8   count;
 116	__u8   pkt_id;
 117	__u32  serial_num;
 118	struct timer_list timer;
 119	struct usb_serial_port *port;
 120	int    seq_counter;
 121	int    insize;
 122	int    outsize;
 123	__u8   inbuffer [GPS_IN_BUFSIZ];  /* tty -> usb */
 124	__u8   outbuffer[GPS_OUT_BUFSIZ]; /* usb -> tty */
 125	__u8   privpkt[4*6];
 126	spinlock_t lock;
 127	struct list_head pktlist;
 128	struct usb_anchor write_urbs;
 129};
 130
 131
 132#define STATE_NEW            0
 133#define STATE_INITIAL_DELAY  1
 134#define STATE_TIMEOUT        2
 135#define STATE_SESSION_REQ1   3
 136#define STATE_SESSION_REQ2   4
 137#define STATE_ACTIVE         5
 138
 139#define STATE_RESET	     8
 140#define STATE_DISCONNECTED   9
 141#define STATE_WAIT_TTY_ACK  10
 142#define STATE_GSP_WAIT_DATA 11
 143
 144#define MODE_NATIVE          0
 145#define MODE_GARMIN_SERIAL   1
 146
 147/* Flags used in garmin_data.flags: */
 148#define FLAGS_SESSION_REPLY_MASK  0x00C0
 149#define FLAGS_SESSION_REPLY1_SEEN 0x0080
 150#define FLAGS_SESSION_REPLY2_SEEN 0x0040
 151#define FLAGS_BULK_IN_ACTIVE      0x0020
 152#define FLAGS_BULK_IN_RESTART     0x0010
 153#define FLAGS_THROTTLED           0x0008
 154#define APP_REQ_SEEN              0x0004
 155#define APP_RESP_SEEN             0x0002
 156#define CLEAR_HALT_REQUIRED       0x0001
 157
 158#define FLAGS_QUEUING             0x0100
 159#define FLAGS_DROP_DATA           0x0800
 160
 161#define FLAGS_GSP_SKIP            0x1000
 162#define FLAGS_GSP_DLESEEN         0x2000
 163
 164
 165
 166
 167
 168
 169/* function prototypes */
 170static int gsp_next_packet(struct garmin_data *garmin_data_p);
 171static int garmin_write_bulk(struct usb_serial_port *port,
 172			     const unsigned char *buf, int count,
 173			     int dismiss_ack);
 174
 175/* some special packets to be send or received */
 176static unsigned char const GARMIN_START_SESSION_REQ[]
 177	= { 0, 0, 0, 0,  5, 0, 0, 0, 0, 0, 0, 0 };
 178static unsigned char const GARMIN_START_SESSION_REPLY[]
 179	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
 180static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
 181	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
 182static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
 183	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
 184static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
 185	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
 186
 187/* packets currently unused, left as documentation */
 188#if 0
 189static unsigned char const GARMIN_APP_LAYER_REPLY[]
 190	= { 0x14, 0, 0, 0 };
 191static unsigned char const GARMIN_START_PVT_REQ[]
 192	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
 193static unsigned char const GARMIN_STOP_PVT_REQ[]
 194	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
 195static unsigned char const PRIVATE_REQ[]
 196	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };
 197#endif
 198
 199
 200static const struct usb_device_id id_table[] = {
 201	/* the same device id seems to be used by all
 202	   usb enabled GPS devices */
 203	{ USB_DEVICE(GARMIN_VENDOR_ID, 3) },
 204	{ }					/* Terminating entry */
 205};
 206MODULE_DEVICE_TABLE(usb, id_table);
 207
 208
 209static inline int getLayerId(const __u8 *usbPacket)
 210{
 211	return __le32_to_cpup((__le32 *)(usbPacket));
 212}
 213
 214static inline int getPacketId(const __u8 *usbPacket)
 215{
 216	return __le32_to_cpup((__le32 *)(usbPacket+4));
 217}
 218
 219static inline int getDataLength(const __u8 *usbPacket)
 220{
 221	return __le32_to_cpup((__le32 *)(usbPacket+8));
 222}
 223
 224
 225/*
 226 * check if the usb-packet in buf contains an abort-transfer command.
 227 * (if yes, all queued data will be dropped)
 228 */
 229static inline int isAbortTrfCmnd(const unsigned char *buf)
 230{
 231	if (memcmp(buf, GARMIN_STOP_TRANSFER_REQ,
 232			sizeof(GARMIN_STOP_TRANSFER_REQ)) == 0 ||
 233	    memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2,
 234			sizeof(GARMIN_STOP_TRANSFER_REQ_V2)) == 0)
 235		return 1;
 236	else
 237		return 0;
 238}
 239
 240
 241
 242static void send_to_tty(struct usb_serial_port *port,
 243			char *data, unsigned int actual_length)
 244{
 245	if (actual_length) {
 246		usb_serial_debug_data(&port->dev, __func__, actual_length, data);
 247		tty_insert_flip_string(&port->port, data, actual_length);
 248		tty_flip_buffer_push(&port->port);
 249	}
 250}
 251
 252
 253/******************************************************************************
 254 * packet queue handling
 255 ******************************************************************************/
 256
 257/*
 258 * queue a received (usb-)packet for later processing
 259 */
 260static int pkt_add(struct garmin_data *garmin_data_p,
 261		   unsigned char *data, unsigned int data_length)
 262{
 263	int state = 0;
 264	int result = 0;
 265	unsigned long flags;
 266	struct garmin_packet *pkt;
 267
 268	/* process only packets containing data ... */
 269	if (data_length) {
 270		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
 271								GFP_ATOMIC);
 272		if (!pkt)
 273			return 0;
 274
 275		pkt->size = data_length;
 276		memcpy(pkt->data, data, data_length);
 277
 278		spin_lock_irqsave(&garmin_data_p->lock, flags);
 279		garmin_data_p->flags |= FLAGS_QUEUING;
 280		result = list_empty(&garmin_data_p->pktlist);
 281		pkt->seq = garmin_data_p->seq_counter++;
 282		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
 283		state = garmin_data_p->state;
 284		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 285
 286		dev_dbg(&garmin_data_p->port->dev,
 287			"%s - added: pkt: %d - %d bytes\n", __func__,
 288			pkt->seq, data_length);
 289
 290		/* in serial mode, if someone is waiting for data from
 291		   the device, convert and send the next packet to tty. */
 292		if (result && (state == STATE_GSP_WAIT_DATA))
 293			gsp_next_packet(garmin_data_p);
 294	}
 295	return result;
 296}
 297
 298
 299/* get the next pending packet */
 300static struct garmin_packet *pkt_pop(struct garmin_data *garmin_data_p)
 301{
 302	unsigned long flags;
 303	struct garmin_packet *result = NULL;
 304
 305	spin_lock_irqsave(&garmin_data_p->lock, flags);
 306	if (!list_empty(&garmin_data_p->pktlist)) {
 307		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
 308		list_del(&result->list);
 309	}
 310	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 311	return result;
 312}
 313
 314
 315/* free up all queued data */
 316static void pkt_clear(struct garmin_data *garmin_data_p)
 317{
 318	unsigned long flags;
 319	struct garmin_packet *result = NULL;
 320
 321	spin_lock_irqsave(&garmin_data_p->lock, flags);
 322	while (!list_empty(&garmin_data_p->pktlist)) {
 323		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
 324		list_del(&result->list);
 325		kfree(result);
 326	}
 327	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 328}
 329
 330
 331/******************************************************************************
 332 * garmin serial protocol handling handling
 333 ******************************************************************************/
 334
 335/* send an ack packet back to the tty */
 336static int gsp_send_ack(struct garmin_data *garmin_data_p, __u8 pkt_id)
 337{
 338	__u8 pkt[10];
 339	__u8 cksum = 0;
 340	__u8 *ptr = pkt;
 341	unsigned  l = 0;
 342
 343	dev_dbg(&garmin_data_p->port->dev, "%s - pkt-id: 0x%X.\n", __func__,
 344			pkt_id);
 345
 346	*ptr++ = DLE;
 347	*ptr++ = ACK;
 348	cksum += ACK;
 349
 350	*ptr++ = 2;
 351	cksum += 2;
 352
 353	*ptr++ = pkt_id;
 354	cksum += pkt_id;
 355
 356	if (pkt_id == DLE)
 357		*ptr++ = DLE;
 358
 359	*ptr++ = 0;
 360	*ptr++ = (-cksum) & 0xFF;
 361	*ptr++ = DLE;
 362	*ptr++ = ETX;
 363
 364	l = ptr-pkt;
 365
 366	send_to_tty(garmin_data_p->port, pkt, l);
 367	return 0;
 368}
 369
 370
 371
 372/*
 373 * called for a complete packet received from tty layer
 374 *
 375 * the complete packet (pktid ... cksum) is in garmin_data_p->inbuf starting
 376 * at GSP_INITIAL_OFFSET.
 377 *
 378 * count - number of bytes in the input buffer including space reserved for
 379 *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet
 380 *         (including pkt-id, data-length a. cksum)
 381 */
 382static int gsp_rec_packet(struct garmin_data *garmin_data_p, int count)
 383{
 384	struct device *dev = &garmin_data_p->port->dev;
 385	unsigned long flags;
 386	const __u8 *recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
 387	__le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;
 388	int cksum = 0;
 389	int n = 0;
 390	int pktid = recpkt[0];
 391	int size = recpkt[1];
 392
 393	usb_serial_debug_data(&garmin_data_p->port->dev, __func__,
 394			      count-GSP_INITIAL_OFFSET, recpkt);
 395
 396	if (size != (count-GSP_INITIAL_OFFSET-3)) {
 397		dev_dbg(dev, "%s - invalid size, expected %d bytes, got %d\n",
 398			__func__, size, (count-GSP_INITIAL_OFFSET-3));
 399		return -EINVPKT;
 400	}
 401
 402	cksum += *recpkt++;
 403	cksum += *recpkt++;
 404
 405	/* sanity check, remove after test ... */
 406	if ((__u8 *)&(usbdata[3]) != recpkt) {
 407		dev_dbg(dev, "%s - ptr mismatch %p - %p\n", __func__,
 408			&(usbdata[4]), recpkt);
 409		return -EINVPKT;
 410	}
 411
 412	while (n < size) {
 413		cksum += *recpkt++;
 414		n++;
 415	}
 416
 417	if (((cksum + *recpkt) & 0xff) != 0) {
 418		dev_dbg(dev, "%s - invalid checksum, expected %02x, got %02x\n",
 419			__func__, -cksum & 0xff, *recpkt);
 420		return -EINVPKT;
 421	}
 422
 423	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
 424	usbdata[1] = __cpu_to_le32(pktid);
 425	usbdata[2] = __cpu_to_le32(size);
 426
 427	garmin_write_bulk(garmin_data_p->port, garmin_data_p->inbuffer,
 428			   GARMIN_PKTHDR_LENGTH+size, 0);
 429
 430	/* if this was an abort-transfer command, flush all
 431	   queued data. */
 432	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
 433		spin_lock_irqsave(&garmin_data_p->lock, flags);
 434		garmin_data_p->flags |= FLAGS_DROP_DATA;
 435		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 436		pkt_clear(garmin_data_p);
 437	}
 438
 439	return count;
 440}
 441
 442
 443
 444/*
 445 * Called for data received from tty
 446 *
 447 * buf contains the data read, it may span more than one packet or even
 448 * incomplete packets
 449 *
 450 * input record should be a serial-record, but it may not be complete.
 451 * Copy it into our local buffer, until an etx is seen (or an error
 452 * occurs).
 453 * Once the record is complete, convert into a usb packet and send it
 454 * to the bulk pipe, send an ack back to the tty.
 455 *
 456 * If the input is an ack, just send the last queued packet to the
 457 * tty layer.
 458 *
 459 * if the input is an abort command, drop all queued data.
 460 */
 461
 462static int gsp_receive(struct garmin_data *garmin_data_p,
 463		       const unsigned char *buf, int count)
 464{
 465	struct device *dev = &garmin_data_p->port->dev;
 466	unsigned long flags;
 467	int offs = 0;
 468	int ack_or_nak_seen = 0;
 469	__u8 *dest;
 470	int size;
 471	/* dleSeen: set if last byte read was a DLE */
 472	int dleSeen;
 473	/* skip: if set, skip incoming data until possible start of
 474	 *       new packet
 475	 */
 476	int skip;
 477	__u8 data;
 478
 479	spin_lock_irqsave(&garmin_data_p->lock, flags);
 480	dest = garmin_data_p->inbuffer;
 481	size = garmin_data_p->insize;
 482	dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
 483	skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
 484	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 485
 486	/* dev_dbg(dev, "%s - dle=%d skip=%d size=%d count=%d\n",
 487		__func__, dleSeen, skip, size, count); */
 488
 489	if (size == 0)
 490		size = GSP_INITIAL_OFFSET;
 491
 492	while (offs < count) {
 493
 494		data = *(buf+offs);
 495		offs++;
 496
 497		if (data == DLE) {
 498			if (skip) { /* start of a new pkt */
 499				skip = 0;
 500				size = GSP_INITIAL_OFFSET;
 501				dleSeen = 1;
 502			} else if (dleSeen) {
 503				dest[size++] = data;
 504				dleSeen = 0;
 505			} else {
 506				dleSeen = 1;
 507			}
 508		} else if (data == ETX) {
 509			if (dleSeen) {
 510				/* packet complete */
 511
 512				data = dest[GSP_INITIAL_OFFSET];
 513
 514				if (data == ACK) {
 515					ack_or_nak_seen = ACK;
 516					dev_dbg(dev, "ACK packet complete.\n");
 517				} else if (data == NAK) {
 518					ack_or_nak_seen = NAK;
 519					dev_dbg(dev, "NAK packet complete.\n");
 520				} else {
 521					dev_dbg(dev, "packet complete - id=0x%X.\n",
 522							data);
 523					gsp_rec_packet(garmin_data_p, size);
 524				}
 525
 526				skip = 1;
 527				size = GSP_INITIAL_OFFSET;
 528				dleSeen = 0;
 529			} else {
 530				dest[size++] = data;
 531			}
 532		} else if (!skip) {
 533
 534			if (dleSeen) {
 535				size = GSP_INITIAL_OFFSET;
 536				dleSeen = 0;
 537			}
 538
 539			dest[size++] = data;
 540		}
 541
 542		if (size >= GPS_IN_BUFSIZ) {
 543			dev_dbg(dev, "%s - packet too large.\n", __func__);
 544			skip = 1;
 545			size = GSP_INITIAL_OFFSET;
 546			dleSeen = 0;
 547		}
 548	}
 549
 550	spin_lock_irqsave(&garmin_data_p->lock, flags);
 551
 552	garmin_data_p->insize = size;
 553
 554	/* copy flags back to structure */
 555	if (skip)
 556		garmin_data_p->flags |= FLAGS_GSP_SKIP;
 557	else
 558		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;
 559
 560	if (dleSeen)
 561		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
 562	else
 563		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;
 564
 565	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 566
 567	if (ack_or_nak_seen) {
 568		if (gsp_next_packet(garmin_data_p) > 0)
 569			garmin_data_p->state = STATE_ACTIVE;
 570		else
 571			garmin_data_p->state = STATE_GSP_WAIT_DATA;
 572	}
 573	return count;
 574}
 575
 576
 577
 578/*
 579 * Sends a usb packet to the tty
 580 *
 581 * Assumes, that all packages and at an usb-packet boundary.
 582 *
 583 * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
 584 */
 585static int gsp_send(struct garmin_data *garmin_data_p,
 586		    const unsigned char *buf, int count)
 587{
 588	struct device *dev = &garmin_data_p->port->dev;
 589	const unsigned char *src;
 590	unsigned char *dst;
 591	int pktid = 0;
 592	int datalen = 0;
 593	int cksum = 0;
 594	int i = 0;
 595	int k;
 596
 597	dev_dbg(dev, "%s - state %d - %d bytes.\n", __func__,
 598		garmin_data_p->state, count);
 599
 600	k = garmin_data_p->outsize;
 601	if ((k+count) > GPS_OUT_BUFSIZ) {
 602		dev_dbg(dev, "packet too large\n");
 603		garmin_data_p->outsize = 0;
 604		return -4;
 605	}
 606
 607	memcpy(garmin_data_p->outbuffer+k, buf, count);
 608	k += count;
 609	garmin_data_p->outsize = k;
 610
 611	if (k >= GARMIN_PKTHDR_LENGTH) {
 612		pktid  = getPacketId(garmin_data_p->outbuffer);
 613		datalen = getDataLength(garmin_data_p->outbuffer);
 614		i = GARMIN_PKTHDR_LENGTH + datalen;
 615		if (k < i)
 616			return 0;
 617	} else {
 618		return 0;
 619	}
 620
 621	dev_dbg(dev, "%s - %d bytes in buffer, %d bytes in pkt.\n", __func__, k, i);
 622
 623	/* garmin_data_p->outbuffer now contains a complete packet */
 624
 625	usb_serial_debug_data(&garmin_data_p->port->dev, __func__, k,
 626			      garmin_data_p->outbuffer);
 627
 628	garmin_data_p->outsize = 0;
 629
 630	if (getLayerId(garmin_data_p->outbuffer) != GARMIN_LAYERID_APPL) {
 631		dev_dbg(dev, "not an application packet (%d)\n",
 632				getLayerId(garmin_data_p->outbuffer));
 633		return -1;
 634	}
 635
 636	if (pktid > 255) {
 637		dev_dbg(dev, "packet-id %d too large\n", pktid);
 638		return -2;
 639	}
 640
 641	if (datalen > 255) {
 642		dev_dbg(dev, "packet-size %d too large\n", datalen);
 643		return -3;
 644	}
 645
 646	/* the serial protocol should be able to handle this packet */
 647
 648	k = 0;
 649	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
 650	for (i = 0; i < datalen; i++) {
 651		if (*src++ == DLE)
 652			k++;
 653	}
 654
 655	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
 656	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
 657		/* can't add stuffing DLEs in place, move data to end
 658		   of buffer ... */
 659		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
 660		memcpy(dst, src, datalen);
 661		src = dst;
 662	}
 663
 664	dst = garmin_data_p->outbuffer;
 665
 666	*dst++ = DLE;
 667	*dst++ = pktid;
 668	cksum += pktid;
 669	*dst++ = datalen;
 670	cksum += datalen;
 671	if (datalen == DLE)
 672		*dst++ = DLE;
 673
 674	for (i = 0; i < datalen; i++) {
 675		__u8 c = *src++;
 676		*dst++ = c;
 677		cksum += c;
 678		if (c == DLE)
 679			*dst++ = DLE;
 680	}
 681
 682	cksum = -cksum & 0xFF;
 683	*dst++ = cksum;
 684	if (cksum == DLE)
 685		*dst++ = DLE;
 686	*dst++ = DLE;
 687	*dst++ = ETX;
 688
 689	i = dst-garmin_data_p->outbuffer;
 690
 691	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);
 692
 693	garmin_data_p->pkt_id = pktid;
 694	garmin_data_p->state  = STATE_WAIT_TTY_ACK;
 695
 696	return i;
 697}
 698
 699
 700/*
 701 * Process the next pending data packet - if there is one
 702 */
 703static int gsp_next_packet(struct garmin_data *garmin_data_p)
 704{
 705	int result = 0;
 706	struct garmin_packet *pkt = NULL;
 707
 708	while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
 709		dev_dbg(&garmin_data_p->port->dev, "%s - next pkt: %d\n", __func__, pkt->seq);
 710		result = gsp_send(garmin_data_p, pkt->data, pkt->size);
 711		if (result > 0) {
 712			kfree(pkt);
 713			return result;
 714		}
 715		kfree(pkt);
 716	}
 717	return result;
 718}
 719
 720
 721
 722/******************************************************************************
 723 * garmin native mode
 724 ******************************************************************************/
 725
 726
 727/*
 728 * Called for data received from tty
 729 *
 730 * The input data is expected to be in garmin usb-packet format.
 731 *
 732 * buf contains the data read, it may span more than one packet
 733 * or even incomplete packets
 734 */
 735static int nat_receive(struct garmin_data *garmin_data_p,
 736		       const unsigned char *buf, int count)
 737{
 738	unsigned long flags;
 739	__u8 *dest;
 740	int offs = 0;
 741	int result = count;
 742	int len;
 743
 744	while (offs < count) {
 745		/* if buffer contains header, copy rest of data */
 746		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
 747			len = GARMIN_PKTHDR_LENGTH
 748			      +getDataLength(garmin_data_p->inbuffer);
 749		else
 750			len = GARMIN_PKTHDR_LENGTH;
 751
 752		if (len >= GPS_IN_BUFSIZ) {
 753			/* seems to be an invalid packet, ignore rest
 754			   of input */
 755			dev_dbg(&garmin_data_p->port->dev,
 756				"%s - packet size too large: %d\n",
 757				__func__, len);
 758			garmin_data_p->insize = 0;
 759			count = 0;
 760			result = -EINVPKT;
 761		} else {
 762			len -= garmin_data_p->insize;
 763			if (len > (count-offs))
 764				len = (count-offs);
 765			if (len > 0) {
 766				dest = garmin_data_p->inbuffer
 767						+ garmin_data_p->insize;
 768				memcpy(dest, buf+offs, len);
 769				garmin_data_p->insize += len;
 770				offs += len;
 771			}
 772		}
 773
 774		/* do we have a complete packet ? */
 775		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
 776			len = GARMIN_PKTHDR_LENGTH+
 777			   getDataLength(garmin_data_p->inbuffer);
 778			if (garmin_data_p->insize >= len) {
 779				garmin_write_bulk(garmin_data_p->port,
 780						   garmin_data_p->inbuffer,
 781						   len, 0);
 782				garmin_data_p->insize = 0;
 783
 784				/* if this was an abort-transfer command,
 785				   flush all queued data. */
 786				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
 787					spin_lock_irqsave(&garmin_data_p->lock,
 788									flags);
 789					garmin_data_p->flags |= FLAGS_DROP_DATA;
 790					spin_unlock_irqrestore(
 791						&garmin_data_p->lock, flags);
 792					pkt_clear(garmin_data_p);
 793				}
 794			}
 795		}
 796	}
 797	return result;
 798}
 799
 800
 801/******************************************************************************
 802 * private packets
 803 ******************************************************************************/
 804
 805static void priv_status_resp(struct usb_serial_port *port)
 806{
 807	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
 808	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;
 809
 810	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
 811	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
 812	pkt[2] = __cpu_to_le32(12);
 813	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
 814	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
 815	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);
 816
 817	send_to_tty(port, (__u8 *)pkt, 6 * 4);
 818}
 819
 820
 821/******************************************************************************
 822 * Garmin specific driver functions
 823 ******************************************************************************/
 824
 825static int process_resetdev_request(struct usb_serial_port *port)
 826{
 827	unsigned long flags;
 828	int status;
 829	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
 830
 831	spin_lock_irqsave(&garmin_data_p->lock, flags);
 832	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
 833	garmin_data_p->state = STATE_RESET;
 834	garmin_data_p->serial_num = 0;
 835	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 836
 837	usb_kill_urb(port->interrupt_in_urb);
 838	dev_dbg(&port->dev, "%s - usb_reset_device\n", __func__);
 839	status = usb_reset_device(port->serial->dev);
 840	if (status)
 841		dev_dbg(&port->dev, "%s - usb_reset_device failed: %d\n",
 842			__func__, status);
 843	return status;
 844}
 845
 846
 847
 848/*
 849 * clear all cached data
 850 */
 851static int garmin_clear(struct garmin_data *garmin_data_p)
 852{
 853	unsigned long flags;
 854
 855	/* flush all queued data */
 856	pkt_clear(garmin_data_p);
 857
 858	spin_lock_irqsave(&garmin_data_p->lock, flags);
 859	garmin_data_p->insize = 0;
 860	garmin_data_p->outsize = 0;
 861	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 862
 863	return 0;
 864}
 865
 866
 867static int garmin_init_session(struct usb_serial_port *port)
 868{
 869	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
 870	int status;
 871	int i;
 872
 873	usb_kill_urb(port->interrupt_in_urb);
 874
 875	status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 876	if (status) {
 877		dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
 878				status);
 879		return status;
 880	}
 881
 882	/*
 883	 * using the initialization method from gpsbabel. See comments in
 884	 * gpsbabel/jeeps/gpslibusb.c gusb_reset_toggles()
 885	 */
 886	dev_dbg(&port->dev, "%s - starting session ...\n", __func__);
 887	garmin_data_p->state = STATE_ACTIVE;
 888
 889	for (i = 0; i < 3; i++) {
 890		status = garmin_write_bulk(port, GARMIN_START_SESSION_REQ,
 891				sizeof(GARMIN_START_SESSION_REQ), 0);
 892		if (status < 0)
 893			goto err_kill_urbs;
 894	}
 895
 896	return 0;
 897
 898err_kill_urbs:
 899	usb_kill_anchored_urbs(&garmin_data_p->write_urbs);
 900	usb_kill_urb(port->interrupt_in_urb);
 901
 902	return status;
 903}
 904
 905
 906
 907static int garmin_open(struct tty_struct *tty, struct usb_serial_port *port)
 908{
 909	unsigned long flags;
 910	int status = 0;
 911	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
 912
 913	spin_lock_irqsave(&garmin_data_p->lock, flags);
 914	garmin_data_p->mode  = initial_mode;
 915	garmin_data_p->count = 0;
 916	garmin_data_p->flags &= FLAGS_SESSION_REPLY1_SEEN;
 917	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 918
 919	/* shutdown any bulk reads that might be going on */
 920	usb_kill_urb(port->read_urb);
 921
 922	if (garmin_data_p->state == STATE_RESET)
 923		status = garmin_init_session(port);
 924
 925	garmin_data_p->state = STATE_ACTIVE;
 926	return status;
 927}
 928
 929
 930static void garmin_close(struct usb_serial_port *port)
 931{
 932	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
 933
 934	dev_dbg(&port->dev, "%s - mode=%d state=%d flags=0x%X\n",
 935		__func__, garmin_data_p->mode, garmin_data_p->state,
 936		garmin_data_p->flags);
 937
 938	garmin_clear(garmin_data_p);
 939
 940	/* shutdown our urbs */
 941	usb_kill_urb(port->read_urb);
 942	usb_kill_anchored_urbs(&garmin_data_p->write_urbs);
 943
 944	/* keep reset state so we know that we must start a new session */
 945	if (garmin_data_p->state != STATE_RESET)
 946		garmin_data_p->state = STATE_DISCONNECTED;
 947}
 948
 949
 950static void garmin_write_bulk_callback(struct urb *urb)
 951{
 952	struct usb_serial_port *port = urb->context;
 953
 954	if (port) {
 955		struct garmin_data *garmin_data_p =
 956					usb_get_serial_port_data(port);
 957
 958		if (getLayerId(urb->transfer_buffer) == GARMIN_LAYERID_APPL) {
 959
 960			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
 961				gsp_send_ack(garmin_data_p,
 962					((__u8 *)urb->transfer_buffer)[4]);
 963			}
 964		}
 965		usb_serial_port_softint(port);
 966	}
 967
 968	/* Ignore errors that resulted from garmin_write_bulk with
 969	   dismiss_ack = 1 */
 970
 971	/* free up the transfer buffer, as usb_free_urb() does not do this */
 972	kfree(urb->transfer_buffer);
 973}
 974
 975
 976static int garmin_write_bulk(struct usb_serial_port *port,
 977			      const unsigned char *buf, int count,
 978			      int dismiss_ack)
 979{
 980	unsigned long flags;
 981	struct usb_serial *serial = port->serial;
 982	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
 983	struct urb *urb;
 984	unsigned char *buffer;
 985	int status;
 986
 987	spin_lock_irqsave(&garmin_data_p->lock, flags);
 988	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
 989	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
 990
 991	buffer = kmemdup(buf, count, GFP_ATOMIC);
 992	if (!buffer)
 993		return -ENOMEM;
 994
 995	urb = usb_alloc_urb(0, GFP_ATOMIC);
 996	if (!urb) {
 997		kfree(buffer);
 998		return -ENOMEM;
 999	}
1000
1001	usb_serial_debug_data(&port->dev, __func__, count, buffer);
1002
1003	usb_fill_bulk_urb(urb, serial->dev,
1004				usb_sndbulkpipe(serial->dev,
1005					port->bulk_out_endpointAddress),
1006				buffer, count,
1007				garmin_write_bulk_callback,
1008				dismiss_ack ? NULL : port);
1009	urb->transfer_flags |= URB_ZERO_PACKET;
1010
1011	if (getLayerId(buffer) == GARMIN_LAYERID_APPL) {
1012
1013		spin_lock_irqsave(&garmin_data_p->lock, flags);
1014		garmin_data_p->flags |= APP_REQ_SEEN;
1015		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1016
1017		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
1018			pkt_clear(garmin_data_p);
1019			garmin_data_p->state = STATE_GSP_WAIT_DATA;
1020		}
1021	}
1022
1023	/* send it down the pipe */
1024	usb_anchor_urb(urb, &garmin_data_p->write_urbs);
1025	status = usb_submit_urb(urb, GFP_ATOMIC);
1026	if (status) {
1027		dev_err(&port->dev,
1028		   "%s - usb_submit_urb(write bulk) failed with status = %d\n",
1029				__func__, status);
1030		count = status;
1031		usb_unanchor_urb(urb);
1032		kfree(buffer);
1033	}
1034
1035	/* we are done with this urb, so let the host driver
1036	 * really free it when it is finished with it */
1037	usb_free_urb(urb);
1038
1039	return count;
1040}
1041
1042static int garmin_write(struct tty_struct *tty, struct usb_serial_port *port,
1043					 const unsigned char *buf, int count)
1044{
1045	struct device *dev = &port->dev;
1046	int pktid, pktsiz, len;
1047	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1048	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;
1049
1050	usb_serial_debug_data(dev, __func__, count, buf);
1051
1052	if (garmin_data_p->state == STATE_RESET)
1053		return -EIO;
1054
1055	/* check for our private packets */
1056	if (count >= GARMIN_PKTHDR_LENGTH) {
1057		len = PRIVPKTSIZ;
1058		if (count < len)
1059			len = count;
1060
1061		memcpy(garmin_data_p->privpkt, buf, len);
1062
1063		pktsiz = getDataLength(garmin_data_p->privpkt);
1064		pktid  = getPacketId(garmin_data_p->privpkt);
1065
1066		if (count == (GARMIN_PKTHDR_LENGTH + pktsiz) &&
1067				getLayerId(garmin_data_p->privpkt) ==
1068						GARMIN_LAYERID_PRIVATE) {
1069
1070			dev_dbg(dev, "%s - processing private request %d\n",
1071				__func__, pktid);
1072
1073			/* drop all unfinished transfers */
1074			garmin_clear(garmin_data_p);
1075
1076			switch (pktid) {
1077			case PRIV_PKTID_SET_MODE:
1078				if (pktsiz != 4)
1079					return -EINVPKT;
1080				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
1081				dev_dbg(dev, "%s - mode set to %d\n",
1082					__func__, garmin_data_p->mode);
1083				break;
1084
1085			case PRIV_PKTID_INFO_REQ:
1086				priv_status_resp(port);
1087				break;
1088
1089			case PRIV_PKTID_RESET_REQ:
1090				process_resetdev_request(port);
1091				break;
1092
1093			case PRIV_PKTID_SET_DEF_MODE:
1094				if (pktsiz != 4)
1095					return -EINVPKT;
1096				initial_mode = __le32_to_cpu(privpkt[3]);
1097				dev_dbg(dev, "%s - initial_mode set to %d\n",
1098					__func__,
1099					garmin_data_p->mode);
1100				break;
1101			}
1102			return count;
1103		}
1104	}
1105
1106	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1107		return gsp_receive(garmin_data_p, buf, count);
1108	} else {	/* MODE_NATIVE */
1109		return nat_receive(garmin_data_p, buf, count);
1110	}
1111}
1112
1113
1114static unsigned int garmin_write_room(struct tty_struct *tty)
1115{
1116	struct usb_serial_port *port = tty->driver_data;
1117	/*
1118	 * Report back the bytes currently available in the output buffer.
1119	 */
1120	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1121	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
1122}
1123
1124
1125static void garmin_read_process(struct garmin_data *garmin_data_p,
1126				 unsigned char *data, unsigned data_length,
1127				 int bulk_data)
1128{
1129	unsigned long flags;
1130
1131	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
1132		/* abort-transfer cmd is active */
1133		dev_dbg(&garmin_data_p->port->dev, "%s - pkt dropped\n", __func__);
1134	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
1135		garmin_data_p->state != STATE_RESET) {
1136
1137		/* if throttling is active or postprecessing is required
1138		   put the received data in the input queue, otherwise
1139		   send it directly to the tty port */
1140		if (garmin_data_p->flags & FLAGS_QUEUING) {
1141			pkt_add(garmin_data_p, data, data_length);
1142		} else if (bulk_data || (data_length >= sizeof(u32) &&
1143				getLayerId(data) == GARMIN_LAYERID_APPL)) {
1144
1145			spin_lock_irqsave(&garmin_data_p->lock, flags);
1146			garmin_data_p->flags |= APP_RESP_SEEN;
1147			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1148
1149			if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
1150				pkt_add(garmin_data_p, data, data_length);
1151			} else {
1152				send_to_tty(garmin_data_p->port, data,
1153						data_length);
1154			}
1155		}
1156		/* ignore system layer packets ... */
1157	}
1158}
1159
1160
1161static void garmin_read_bulk_callback(struct urb *urb)
1162{
1163	unsigned long flags;
1164	struct usb_serial_port *port = urb->context;
1165	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1166	unsigned char *data = urb->transfer_buffer;
1167	int status = urb->status;
1168	int retval;
1169
1170	if (status) {
1171		dev_dbg(&urb->dev->dev, "%s - nonzero read bulk status received: %d\n",
1172			__func__, status);
1173		return;
1174	}
1175
1176	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
1177
1178	garmin_read_process(garmin_data_p, data, urb->actual_length, 1);
1179
1180	if (urb->actual_length == 0 &&
1181			(garmin_data_p->flags & FLAGS_BULK_IN_RESTART) != 0) {
1182		spin_lock_irqsave(&garmin_data_p->lock, flags);
1183		garmin_data_p->flags &= ~FLAGS_BULK_IN_RESTART;
1184		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1185		retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1186		if (retval)
1187			dev_err(&port->dev,
1188				"%s - failed resubmitting read urb, error %d\n",
1189				__func__, retval);
1190	} else if (urb->actual_length > 0) {
1191		/* Continue trying to read until nothing more is received  */
1192		if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1193			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1194			if (retval)
1195				dev_err(&port->dev,
1196					"%s - failed resubmitting read urb, error %d\n",
1197					__func__, retval);
1198		}
1199	} else {
1200		dev_dbg(&port->dev, "%s - end of bulk data\n", __func__);
1201		spin_lock_irqsave(&garmin_data_p->lock, flags);
1202		garmin_data_p->flags &= ~FLAGS_BULK_IN_ACTIVE;
1203		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1204	}
1205}
1206
1207
1208static void garmin_read_int_callback(struct urb *urb)
1209{
1210	unsigned long flags;
1211	int retval;
1212	struct usb_serial_port *port = urb->context;
1213	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1214	unsigned char *data = urb->transfer_buffer;
1215	int status = urb->status;
1216
1217	switch (status) {
1218	case 0:
1219		/* success */
1220		break;
1221	case -ECONNRESET:
1222	case -ENOENT:
1223	case -ESHUTDOWN:
1224		/* this urb is terminated, clean up */
1225		dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
1226			__func__, status);
1227		return;
1228	default:
1229		dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
1230			__func__, status);
1231		return;
1232	}
1233
1234	usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
1235			      urb->transfer_buffer);
1236
1237	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
1238		memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
1239				sizeof(GARMIN_BULK_IN_AVAIL_REPLY)) == 0) {
1240
1241		dev_dbg(&port->dev, "%s - bulk data available.\n", __func__);
1242
1243		if ((garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE) == 0) {
1244
1245			/* bulk data available */
1246			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
1247			if (retval) {
1248				dev_err(&port->dev,
1249				 "%s - failed submitting read urb, error %d\n",
1250							__func__, retval);
1251			} else {
1252				spin_lock_irqsave(&garmin_data_p->lock, flags);
1253				garmin_data_p->flags |= FLAGS_BULK_IN_ACTIVE;
1254				spin_unlock_irqrestore(&garmin_data_p->lock,
1255									flags);
1256			}
1257		} else {
1258			/* bulk-in transfer still active */
1259			spin_lock_irqsave(&garmin_data_p->lock, flags);
1260			garmin_data_p->flags |= FLAGS_BULK_IN_RESTART;
1261			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1262		}
1263
1264	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
1265			 && memcmp(data, GARMIN_START_SESSION_REPLY,
1266				 sizeof(GARMIN_START_SESSION_REPLY)) == 0) {
1267
1268		spin_lock_irqsave(&garmin_data_p->lock, flags);
1269		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
1270		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1271
1272		/* save the serial number */
1273		garmin_data_p->serial_num = __le32_to_cpup(
1274					(__le32 *)(data+GARMIN_PKTHDR_LENGTH));
1275
1276		dev_dbg(&port->dev, "%s - start-of-session reply seen - serial %u.\n",
1277			__func__, garmin_data_p->serial_num);
1278	}
1279
1280	garmin_read_process(garmin_data_p, data, urb->actual_length, 0);
1281
1282	retval = usb_submit_urb(urb, GFP_ATOMIC);
1283	if (retval)
1284		dev_err(&urb->dev->dev,
1285			"%s - Error %d submitting interrupt urb\n",
1286			__func__, retval);
1287}
1288
1289
1290/*
1291 * Sends the next queued packt to the tty port (garmin native mode only)
1292 * and then sets a timer to call itself again until all queued data
1293 * is sent.
1294 */
1295static int garmin_flush_queue(struct garmin_data *garmin_data_p)
1296{
1297	unsigned long flags;
1298	struct garmin_packet *pkt;
1299
1300	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
1301		pkt = pkt_pop(garmin_data_p);
1302		if (pkt != NULL) {
1303			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
1304			kfree(pkt);
1305			mod_timer(&garmin_data_p->timer, (1)+jiffies);
1306
1307		} else {
1308			spin_lock_irqsave(&garmin_data_p->lock, flags);
1309			garmin_data_p->flags &= ~FLAGS_QUEUING;
1310			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
1311		}
1312	}
1313	return 0;
1314}
1315
1316
1317static void garmin_throttle(struct tty_struct *tty)
1318{
1319	struct usb_serial_port *port = tty->driver_data;
1320	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1321
1322	/* set flag, data received will be put into a queue
1323	   for later processing */
1324	spin_lock_irq(&garmin_data_p->lock);
1325	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
1326	spin_unlock_irq(&garmin_data_p->lock);
1327}
1328
1329
1330static void garmin_unthrottle(struct tty_struct *tty)
1331{
1332	struct usb_serial_port *port = tty->driver_data;
1333	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1334	int status;
1335
1336	spin_lock_irq(&garmin_data_p->lock);
1337	garmin_data_p->flags &= ~FLAGS_THROTTLED;
1338	spin_unlock_irq(&garmin_data_p->lock);
1339
1340	/* in native mode send queued data to tty, in
1341	   serial mode nothing needs to be done here */
1342	if (garmin_data_p->mode == MODE_NATIVE)
1343		garmin_flush_queue(garmin_data_p);
1344
1345	if ((garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE) != 0) {
1346		status = usb_submit_urb(port->read_urb, GFP_KERNEL);
1347		if (status)
1348			dev_err(&port->dev,
1349				"%s - failed resubmitting read urb, error %d\n",
1350				__func__, status);
1351	}
1352}
1353
1354/*
1355 * The timer is currently only used to send queued packets to
1356 * the tty in cases where the protocol provides no own handshaking
1357 * to initiate the transfer.
1358 */
1359static void timeout_handler(struct timer_list *t)
1360{
1361	struct garmin_data *garmin_data_p = from_timer(garmin_data_p, t, timer);
1362
1363	/* send the next queued packet to the tty port */
1364	if (garmin_data_p->mode == MODE_NATIVE)
1365		if (garmin_data_p->flags & FLAGS_QUEUING)
1366			garmin_flush_queue(garmin_data_p);
1367}
1368
1369
1370
1371static int garmin_port_probe(struct usb_serial_port *port)
1372{
1373	int status;
1374	struct garmin_data *garmin_data_p;
1375
1376	garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
1377	if (!garmin_data_p)
1378		return -ENOMEM;
1379
1380	timer_setup(&garmin_data_p->timer, timeout_handler, 0);
1381	spin_lock_init(&garmin_data_p->lock);
1382	INIT_LIST_HEAD(&garmin_data_p->pktlist);
1383	garmin_data_p->port = port;
1384	garmin_data_p->state = 0;
1385	garmin_data_p->flags = 0;
1386	garmin_data_p->count = 0;
1387	init_usb_anchor(&garmin_data_p->write_urbs);
1388	usb_set_serial_port_data(port, garmin_data_p);
1389
1390	status = garmin_init_session(port);
1391	if (status)
1392		goto err_free;
1393
1394	return 0;
1395err_free:
1396	kfree(garmin_data_p);
1397
1398	return status;
1399}
1400
1401
1402static void garmin_port_remove(struct usb_serial_port *port)
1403{
1404	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
1405
1406	usb_kill_anchored_urbs(&garmin_data_p->write_urbs);
1407	usb_kill_urb(port->interrupt_in_urb);
1408	timer_shutdown_sync(&garmin_data_p->timer);
1409	kfree(garmin_data_p);
1410}
1411
1412
1413/* All of the device info needed */
1414static struct usb_serial_driver garmin_device = {
1415	.driver = {
1416		.owner       = THIS_MODULE,
1417		.name        = "garmin_gps",
1418	},
1419	.description         = "Garmin GPS usb/tty",
1420	.id_table            = id_table,
1421	.num_ports           = 1,
1422	.open                = garmin_open,
1423	.close               = garmin_close,
1424	.throttle            = garmin_throttle,
1425	.unthrottle          = garmin_unthrottle,
1426	.port_probe		= garmin_port_probe,
1427	.port_remove		= garmin_port_remove,
1428	.write               = garmin_write,
1429	.write_room          = garmin_write_room,
1430	.write_bulk_callback = garmin_write_bulk_callback,
1431	.read_bulk_callback  = garmin_read_bulk_callback,
1432	.read_int_callback   = garmin_read_int_callback,
1433};
1434
1435static struct usb_serial_driver * const serial_drivers[] = {
1436	&garmin_device, NULL
1437};
1438
1439module_usb_serial_driver(serial_drivers, id_table);
1440
1441MODULE_AUTHOR(DRIVER_AUTHOR);
1442MODULE_DESCRIPTION(DRIVER_DESC);
1443MODULE_LICENSE("GPL");
1444
1445module_param(initial_mode, int, 0444);
1446MODULE_PARM_DESC(initial_mode, "Initial mode");