summaryrefslogtreecommitdiffstats
path: root/drivers/usb/serial/garmin_gps.c
blob: 8e6a66e38db27ecd3fd7e97ffdbce4e80e79eff1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
/*
 * Garmin GPS driver
 *
 * Copyright (C) 2006,2007 Hermann Kneissel herkne@users.sourceforge.net
 *
 * The latest version of the driver can be found at
 * http://sourceforge.net/projects/garmin-gps/
 *
 * This driver has been derived from v2.1 of the visor driver.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111 USA
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <asm/atomic.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>

/* the mode to be set when the port ist opened */
static int initial_mode = 1;

/* debug flag */
static int debug;

#define GARMIN_VENDOR_ID             0x091E

/*
 * Version Information
 */

#define VERSION_MAJOR	0
#define VERSION_MINOR	31

#define _STR(s) #s
#define _DRIVER_VERSION(a, b) "v" _STR(a) "." _STR(b)
#define DRIVER_VERSION _DRIVER_VERSION(VERSION_MAJOR, VERSION_MINOR)
#define DRIVER_AUTHOR "hermann kneissel"
#define DRIVER_DESC "garmin gps driver"

/* error codes returned by the driver */
#define EINVPKT	1000	/* invalid packet structure */


/* size of the header of a packet using the usb protocol */
#define GARMIN_PKTHDR_LENGTH	12

/* max. possible size of a packet using the serial protocol */
#define MAX_SERIAL_PKT_SIZ (3 + 255 + 3)

/*  max. possible size of a packet with worst case stuffing */
#define MAX_SERIAL_PKT_SIZ_STUFFED (MAX_SERIAL_PKT_SIZ + 256)

/* size of a buffer able to hold a complete (no stuffing) packet
 * (the document protocol does not contain packets with a larger
 *  size, but in theory a packet may be 64k+12 bytes - if in
 *  later protocol versions larger packet sizes occur, this value
 *  should be increased accordingly, so the input buffer is always
 *  large enough the store a complete packet inclusive header) */
#define GPS_IN_BUFSIZ  (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ)

/* size of a buffer able to hold a complete (incl. stuffing) packet */
#define GPS_OUT_BUFSIZ (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ_STUFFED)

/* where to place the packet id of a serial packet, so we can
 * prepend the usb-packet header without the need to move the
 * packets data */
#define GSP_INITIAL_OFFSET (GARMIN_PKTHDR_LENGTH-2)

/* max. size of incoming private packets (header+1 param) */
#define PRIVPKTSIZ (GARMIN_PKTHDR_LENGTH+4)

#define GARMIN_LAYERID_TRANSPORT  0
#define GARMIN_LAYERID_APPL      20
/* our own layer-id to use for some control mechanisms */
#define GARMIN_LAYERID_PRIVATE	0x01106E4B

#define GARMIN_PKTID_PVT_DATA	51
#define GARMIN_PKTID_L001_COMMAND_DATA 10

#define CMND_ABORT_TRANSFER 0

/* packet ids used in private layer */
#define PRIV_PKTID_SET_DEBUG	1
#define PRIV_PKTID_SET_MODE	2
#define PRIV_PKTID_INFO_REQ	3
#define PRIV_PKTID_INFO_RESP	4
#define PRIV_PKTID_RESET_REQ	5
#define PRIV_PKTID_SET_DEF_MODE	6


#define ETX	0x03
#define DLE	0x10
#define ACK	0x06
#define NAK	0x15

/* structure used to queue incoming packets */
struct garmin_packet {
	struct list_head  list;
	int               seq;
	/* the real size of the data array, always > 0 */
	int               size;
	__u8              data[1];
};

/* structure used to keep the current state of the driver */
struct garmin_data {
	__u8   state;
	__u16  flags;
	__u8   mode;
	__u8   ignorePkts;
	__u8   count;
	__u8   pkt_id;
	__u32  serial_num;
	struct timer_list timer;
	struct usb_serial_port *port;
	int    seq_counter;
	int    insize;
	int    outsize;
	__u8   inbuffer [GPS_IN_BUFSIZ];  /* tty -> usb */
	__u8   outbuffer[GPS_OUT_BUFSIZ]; /* usb -> tty */
	__u8   privpkt[4*6];
	atomic_t req_count;
	atomic_t resp_count;
	spinlock_t lock;
	struct list_head pktlist;
};


#define STATE_NEW            0
#define STATE_INITIAL_DELAY  1
#define STATE_TIMEOUT        2
#define STATE_SESSION_REQ1   3
#define STATE_SESSION_REQ2   4
#define STATE_ACTIVE         5

#define STATE_RESET	     8
#define STATE_DISCONNECTED   9
#define STATE_WAIT_TTY_ACK  10
#define STATE_GSP_WAIT_DATA 11

#define MODE_NATIVE          0
#define MODE_GARMIN_SERIAL   1

/* Flags used in garmin_data.flags: */
#define FLAGS_SESSION_REPLY_MASK  0x00C0
#define FLAGS_SESSION_REPLY1_SEEN 0x0080
#define FLAGS_SESSION_REPLY2_SEEN 0x0040
#define FLAGS_BULK_IN_ACTIVE      0x0020
#define FLAGS_BULK_IN_RESTART     0x0010
#define FLAGS_THROTTLED           0x0008
#define CLEAR_HALT_REQUIRED       0x0001

#define FLAGS_QUEUING             0x0100
#define FLAGS_DROP_DATA           0x0800

#define FLAGS_GSP_SKIP            0x1000
#define FLAGS_GSP_DLESEEN         0x2000






/* function prototypes */
static void gsp_next_packet(struct garmin_data *garmin_data_p);
static int  garmin_write_bulk(struct usb_serial_port *port,
			     const unsigned char *buf, int count,
			     int dismiss_ack);

/* some special packets to be send or received */
static unsigned char const GARMIN_START_SESSION_REQ[]
	= { 0, 0, 0, 0,  5, 0, 0, 0, 0, 0, 0, 0 };
static unsigned char const GARMIN_START_SESSION_REQ2[]
	= { 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0 };
static unsigned char const GARMIN_START_SESSION_REPLY[]
	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
static unsigned char const GARMIN_SESSION_ACTIVE_REPLY[]
	= { 0, 0, 0, 0, 17, 0, 0, 0, 4, 0, 0, 0, 0, 16, 0, 0 };
static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
static unsigned char const GARMIN_APP_LAYER_REPLY[]
	= { 0x14, 0, 0, 0 };
static unsigned char const GARMIN_START_PVT_REQ[]
	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
static unsigned char const GARMIN_STOP_PVT_REQ[]
	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
static unsigned char const PRIVATE_REQ[]
	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };



static struct usb_device_id id_table [] = {
	/* the same device id seems to be used by all
	   usb enabled GPS devices */
	{ USB_DEVICE(GARMIN_VENDOR_ID, 3) },
	{ }					/* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, id_table);

static struct usb_driver garmin_driver = {
	.name =		"garmin_gps",
	.probe =	usb_serial_probe,
	.disconnect =	usb_serial_disconnect,
	.id_table =	id_table,
	.no_dynamic_id = 1,
};


static inline int noResponseFromAppLayer(struct garmin_data *garmin_data_p)
{
	return atomic_read(&garmin_data_p->req_count) ==
				atomic_read(&garmin_data_p->resp_count);
}


static inline int getLayerId(const __u8 *usbPacket)
{
	return __le32_to_cpup((__le32 *)(usbPacket));
}

static inline int getPacketId(const __u8 *usbPacket)
{
	return __le32_to_cpup((__le32 *)(usbPacket+4));
}

static inline int getDataLength(const __u8 *usbPacket)
{
	return __le32_to_cpup((__le32 *)(usbPacket+8));
}


/*
 * check if the usb-packet in buf contains an abort-transfer command.
 * (if yes, all queued data will be dropped)
 */
static inline int isAbortTrfCmnd(const unsigned char *buf)
{
	if (0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ,
					sizeof(GARMIN_STOP_TRANSFER_REQ)) ||
	    0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2,
					sizeof(GARMIN_STOP_TRANSFER_REQ_V2)))
		return 1;
	else
		return 0;
}



static void send_to_tty(struct usb_serial_port *port,
			char *data, unsigned int actual_length)
{
	struct tty_struct *tty = tty_port_tty_get(&port->port);

	if (tty && actual_length) {

		usb_serial_debug_data(debug, &port->dev,
					__func__, actual_length, data);

		tty_buffer_request_room(tty, actual_length);
		tty_insert_flip_string(tty, data, actual_length);
		tty_flip_buffer_push(tty);
	}
	tty_kref_put(tty);
}


/******************************************************************************
 * packet queue handling
 ******************************************************************************/

/*
 * queue a received (usb-)packet for later processing
 */
static int pkt_add(struct garmin_data *garmin_data_p,
		   unsigned char *data, unsigned int data_length)
{
	int state = 0;
	int result = 0;
	unsigned long flags;
	struct garmin_packet *pkt;

	/* process only packets containg data ... */
	if (data_length) {
		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
								GFP_ATOMIC);
		if (pkt == NULL) {
			dev_err(&garmin_data_p->port->dev, "out of memory\n");
			return 0;
		}
		pkt->size = data_length;
		memcpy(pkt->data, data, data_length);

		spin_lock_irqsave(&garmin_data_p->lock, flags);
		garmin_data_p->flags |= FLAGS_QUEUING;
		result = list_empty(&garmin_data_p->pktlist);
		pkt->seq = garmin_data_p->seq_counter++;
		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
		state = garmin_data_p->state;
		spin_unlock_irqrestore(&garmin_data_p->lock, flags);

		/* in serial mode, if someone is waiting for data from
		   the device, iconvert and send the next packet to tty. */
		if (result && (state == STATE_GSP_WAIT_DATA))
			gsp_next_packet(garmin_data_p);
	}
	return result;
}


/* get the next pending packet */
static struct garmin_packet *pkt_pop(struct garmin_data *garmin_data_p)
{
	unsigned long flags;
	struct garmin_packet *result = NULL;

	spin_lock_irqsave(&garmin_data_p->lock, flags);
	if (!list_empty(&garmin_data_p->pktlist)) {
		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
		list_del(&result->list);
	}
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
	return result;
}


/* free up all queued data */
static void pkt_clear(struct garmin_data *garmin_data_p)
{
	unsigned long flags;
	struct garmin_packet *result = NULL;

	dbg("%s", __func__);

	spin_lock_irqsave(&garmin_data_p->lock, flags);
	while (!list_empty(&garmin_data_p->pktlist)) {
		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
		list_del(&result->list);
		kfree(result);
	}
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
}


/******************************************************************************
 * garmin serial protocol handling handling
 ******************************************************************************/

/* send an ack packet back to the tty */
static int gsp_send_ack(struct garmin_data *garmin_data_p, __u8 pkt_id)
{
	__u8 pkt[10];
	__u8 cksum = 0;
	__u8 *ptr = pkt;
	unsigned  l = 0;

	dbg("%s - pkt-id: 0x%X.", __func__, 0xFF & pkt_id);

	*ptr++ = DLE;
	*ptr++ = ACK;
	cksum += ACK;

	*ptr++ = 2;
	cksum += 2;

	*ptr++ = pkt_id;
	cksum += pkt_id;

	if (pkt_id == DLE)
		*ptr++ = DLE;

	*ptr++ = 0;
	*ptr++ = 0xFF & (-cksum);
	*ptr++ = DLE;
	*ptr++ = ETX;

	l = ptr-pkt;

	send_to_tty(garmin_data_p->port, pkt, l);
	return 0;
}



/*
 * called for a complete packet received from tty layer
 *
 * the complete packet (pkzid ... cksum) is in garmin_data_p->inbuf starting
 * at GSP_INITIAL_OFFSET.
 *
 * count - number of bytes in the input buffer including space reserved for
 *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet
 *         (including pkt-id, data-length a. cksum)
 */
static int gsp_rec_packet(struct garmin_data *garmin_data_p, int count)
{
	const __u8 *recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
	__le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;

	int cksum = 0;
	int n = 0;
	int pktid = recpkt[0];
	int size = recpkt[1];

	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
			       __func__, count-GSP_INITIAL_OFFSET, recpkt);

	if (size != (count-GSP_INITIAL_OFFSET-3)) {
		dbg("%s - invalid size, expected %d bytes, got %d",
			__func__, size, (count-GSP_INITIAL_OFFSET-3));
		return -EINVPKT;
	}

	cksum += *recpkt++;
	cksum += *recpkt++;

	/* sanity check, remove after test ... */
	if ((__u8 *)&(usbdata[3]) != recpkt) {
		dbg("%s - ptr mismatch %p - %p",
			__func__, &(usbdata[4]), recpkt);
		return -EINVPKT;
	}

	while (n < size) {
		cksum += *recpkt++;
		n++;
	}

	if ((0xff & (cksum + *recpkt)) != 0) {
		dbg("%s - invalid checksum, expected %02x, got %02x",
			__func__, 0xff & -cksum, 0xff & *recpkt);
		return -EINVPKT;
	}

	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
	usbdata[1] = __cpu_to_le32(pktid);
	usbdata[2] = __cpu_to_le32(size);

	garmin_write_bulk(garmin_data_p->port, garmin_data_p->inbuffer,
			   GARMIN_PKTHDR_LENGTH+size, 0);

	/* if this was an abort-transfer command, flush all
	   queued data. */
	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
		garmin_data_p->flags |= FLAGS_DROP_DATA;
		pkt_clear(garmin_data_p);
	}

	return count;
}



/*
 * Called for data received from tty
 *
 * buf contains the data read, it may span more than one packet or even
 * incomplete packets
 *
 * input record should be a serial-record, but it may not be complete.
 * Copy it into our local buffer, until an etx is seen (or an error
 * occurs).
 * Once the record is complete, convert into a usb packet and send it
 * to the bulk pipe, send an ack back to the tty.
 *
 * If the input is an ack, just send the last queued packet to the
 * tty layer.
 *
 * if the input is an abort command, drop all queued data.
 */

static int gsp_receive(struct garmin_data *garmin_data_p,
		       const unsigned char *buf, int count)
{
	unsigned long flags;
	int offs = 0;
	int ack_or_nak_seen = 0;
	int i = 0;
	__u8 *dest;
	int size;
	/* dleSeen: set if last byte read was a DLE */
	int dleSeen;
	/* skip: if set, skip incoming data until possible start of
	 *       new packet
	 */
	int skip;
	__u8 data;

	spin_lock_irqsave(&garmin_data_p->lock, flags);
	dest = garmin_data_p->inbuffer;
	size = garmin_data_p->insize;
	dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
	skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);

	dbg("%s - dle=%d skip=%d size=%d count=%d",
		__func__, dleSeen, skip, size, count);

	if (size == 0)
		size = GSP_INITIAL_OFFSET;

	while (offs < count) {

		data = *(buf+offs);
		offs++;

		if (data == DLE) {
			if (skip) { /* start of a new pkt */
				skip = 0;
				size = GSP_INITIAL_OFFSET;
				dleSeen = 1;
			} else if (dleSeen) {
				dest[size++] = data;
				dleSeen = 0;
			} else {
				dleSeen = 1;
			}
		} else if (data == ETX) {
			if (dleSeen) {
				/* packet complete */

				data = dest[GSP_INITIAL_OFFSET];

				if (data == ACK) {
					ack_or_nak_seen = ACK;
					dbg("ACK packet complete.");
				} else if (data == NAK) {
					ack_or_nak_seen = NAK;
					dbg("NAK packet complete.");
				} else {
					dbg("packet complete - id=0x%X.",
						0xFF & data);
					gsp_rec_packet(garmin_data_p, size);
				}

				skip = 1;
				size = GSP_INITIAL_OFFSET;
				dleSeen = 0;
			} else {
				dest[size++] = data;
			}
		} else if (!skip) {

			if (dleSeen) {
				dbg("non-masked DLE at %d - restarting", i);
				size = GSP_INITIAL_OFFSET;
				dleSeen = 0;
			}

			dest[size++] = data;
		}

		if (size >= GPS_IN_BUFSIZ) {
			dbg("%s - packet too large.", __func__);
			skip = 1;
			size = GSP_INITIAL_OFFSET;
			dleSeen = 0;
		}
	}

	spin_lock_irqsave(&garmin_data_p->lock, flags);

	garmin_data_p->insize = size;

	/* copy flags back to structure */
	if (skip)
		garmin_data_p->flags |= FLAGS_GSP_SKIP;
	else
		garmin_data_p->flags &= ~FLAGS_GSP_SKIP;

	if (dleSeen)
		garmin_data_p->flags |= FLAGS_GSP_DLESEEN;
	else
		garmin_data_p->flags &= ~FLAGS_GSP_DLESEEN;

	if (ack_or_nak_seen)
		garmin_data_p->state = STATE_GSP_WAIT_DATA;

	spin_unlock_irqrestore(&garmin_data_p->lock, flags);

	if (ack_or_nak_seen)
		gsp_next_packet(garmin_data_p);
	return count;
}




/*
 * Sends a usb packet to the tty
 *
 * Assumes, that all packages and at an usb-packet boundary.
 *
 * return <0 on error, 0 if packet is incomplete or > 0 if packet was sent
 */
static int gsp_send(struct garmin_data *garmin_data_p,
		    const unsigned char *buf, int count)
{
	const unsigned char *src;
	unsigned char *dst;
	int pktid = 0;
	int datalen = 0;
	int cksum = 0;
	int i = 0;
	int k;

	dbg("%s - state %d - %d bytes.", __func__,
					garmin_data_p->state, count);

	k = garmin_data_p->outsize;
	if ((k+count) > GPS_OUT_BUFSIZ) {
		dbg("packet too large");
		garmin_data_p->outsize = 0;
		return -4;
	}

	memcpy(garmin_data_p->outbuffer+k, buf, count);
	k += count;
	garmin_data_p->outsize = k;

	if (k >= GARMIN_PKTHDR_LENGTH) {
		pktid  = getPacketId(garmin_data_p->outbuffer);
		datalen = getDataLength(garmin_data_p->outbuffer);
		i = GARMIN_PKTHDR_LENGTH + datalen;
		if (k < i)
			return 0;
	} else {
		return 0;
	}

	dbg("%s - %d bytes in buffer, %d bytes in pkt.", __func__, k, i);

	/* garmin_data_p->outbuffer now contains a complete packet */

	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
				__func__, k, garmin_data_p->outbuffer);

	garmin_data_p->outsize = 0;

	if (GARMIN_LAYERID_APPL != getLayerId(garmin_data_p->outbuffer)) {
		dbg("not an application packet (%d)",
				getLayerId(garmin_data_p->outbuffer));
		return -1;
	}

	if (pktid > 255) {
		dbg("packet-id %d too large", pktid);
		return -2;
	}

	if (datalen > 255) {
		dbg("packet-size %d too large", datalen);
		return -3;
	}

	/* the serial protocol should be able to handle this packet */

	k = 0;
	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
	for (i = 0; i < datalen; i++) {
		if (*src++ == DLE)
			k++;
	}

	src = garmin_data_p->outbuffer+GARMIN_PKTHDR_LENGTH;
	if (k > (GARMIN_PKTHDR_LENGTH-2)) {
		/* can't add stuffing DLEs in place, move data to end
		   of buffer ... */
		dst = garmin_data_p->outbuffer+GPS_OUT_BUFSIZ-datalen;
		memcpy(dst, src, datalen);
		src = dst;
	}

	dst = garmin_data_p->outbuffer;

	*dst++ = DLE;
	*dst++ = pktid;
	cksum += pktid;
	*dst++ = datalen;
	cksum += datalen;
	if (datalen == DLE)
		*dst++ = DLE;

	for (i = 0; i < datalen; i++) {
		__u8 c = *src++;
		*dst++ = c;
		cksum += c;
		if (c == DLE)
			*dst++ = DLE;
	}

	cksum = 0xFF & -cksum;
	*dst++ = cksum;
	if (cksum == DLE)
		*dst++ = DLE;
	*dst++ = DLE;
	*dst++ = ETX;

	i = dst-garmin_data_p->outbuffer;

	send_to_tty(garmin_data_p->port, garmin_data_p->outbuffer, i);

	garmin_data_p->pkt_id = pktid;
	garmin_data_p->state  = STATE_WAIT_TTY_ACK;

	return i;
}





/*
 * Process the next pending data packet - if there is one
 */
static void gsp_next_packet(struct garmin_data *garmin_data_p)
{
	struct garmin_packet *pkt = NULL;

	while ((pkt = pkt_pop(garmin_data_p)) != NULL) {
		dbg("%s - next pkt: %d", __func__, pkt->seq);
		if (gsp_send(garmin_data_p, pkt->data, pkt->size) > 0) {
			kfree(pkt);
			return;
		}
		kfree(pkt);
	}
}




/******************************************************************************
 * garmin native mode
 ******************************************************************************/


/*
 * Called for data received from tty
 *
 * The input data is expected to be in garmin usb-packet format.
 *
 * buf contains the data read, it may span more than one packet
 * or even incomplete packets
 */
static int nat_receive(struct garmin_data *garmin_data_p,
		       const unsigned char *buf, int count)
{
	unsigned long flags;
	__u8 *dest;
	int offs = 0;
	int result = count;
	int len;

	while (offs < count) {
		/* if buffer contains header, copy rest of data */
		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH)
			len = GARMIN_PKTHDR_LENGTH
			      +getDataLength(garmin_data_p->inbuffer);
		else
			len = GARMIN_PKTHDR_LENGTH;

		if (len >= GPS_IN_BUFSIZ) {
			/* seems to be an invalid packet, ignore rest
			   of input */
			dbg("%s - packet size too large: %d", __func__, len);
			garmin_data_p->insize = 0;
			count = 0;
			result = -EINVPKT;
		} else {
			len -= garmin_data_p->insize;
			if (len > (count-offs))
				len = (count-offs);
			if (len > 0) {
				dest = garmin_data_p->inbuffer
						+ garmin_data_p->insize;
				memcpy(dest, buf+offs, len);
				garmin_data_p->insize += len;
				offs += len;
			}
		}

		/* do we have a complete packet ? */
		if (garmin_data_p->insize >= GARMIN_PKTHDR_LENGTH) {
			len = GARMIN_PKTHDR_LENGTH+
			   getDataLength(garmin_data_p->inbuffer);
			if (garmin_data_p->insize >= len) {
				garmin_write_bulk(garmin_data_p->port,
						   garmin_data_p->inbuffer,
						   len, 0);
				garmin_data_p->insize = 0;

				/* if this was an abort-transfer command,
				   flush all queued data. */
				if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
					spin_lock_irqsave(&garmin_data_p->lock,
									flags);
					garmin_data_p->flags |= FLAGS_DROP_DATA;
					spin_unlock_irqrestore(
						&garmin_data_p->lock, flags);
					pkt_clear(garmin_data_p);
				}
			}
		}
	}
	return result;
}


/******************************************************************************
 * private packets
 ******************************************************************************/

static void priv_status_resp(struct usb_serial_port *port)
{
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
	__le32 *pkt = (__le32 *)garmin_data_p->privpkt;

	pkt[0] = __cpu_to_le32(GARMIN_LAYERID_PRIVATE);
	pkt[1] = __cpu_to_le32(PRIV_PKTID_INFO_RESP);
	pkt[2] = __cpu_to_le32(12);
	pkt[3] = __cpu_to_le32(VERSION_MAJOR << 16 | VERSION_MINOR);
	pkt[4] = __cpu_to_le32(garmin_data_p->mode);
	pkt[5] = __cpu_to_le32(garmin_data_p->serial_num);

	send_to_tty(port, (__u8 *)pkt, 6 * 4);
}


/******************************************************************************
 * Garmin specific driver functions
 ******************************************************************************/

static int process_resetdev_request(struct usb_serial_port *port)
{
	unsigned long flags;
	int status;
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);

	spin_lock_irqsave(&garmin_data_p->lock, flags);
	garmin_data_p->flags &= ~(CLEAR_HALT_REQUIRED);
	garmin_data_p->state = STATE_RESET;
	garmin_data_p->serial_num = 0;
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);

	usb_kill_urb(port->interrupt_in_urb);
	dbg("%s - usb_reset_device", __func__);
	status = usb_reset_device(port->serial->dev);
	if (status)
		dbg("%s - usb_reset_device failed: %d",
			__func__, status);
	return status;
}



/*
 * clear all cached data
 */
static int garmin_clear(struct garmin_data *garmin_data_p)
{
	unsigned long flags;
	int status = 0;

	struct usb_serial_port *port = garmin_data_p->port;

	if (port != NULL && atomic_read(&garmin_data_p->resp_count)) {
		/* send a terminate command */
		status = garmin_write_bulk(port, GARMIN_STOP_TRANSFER_REQ,
					sizeof(GARMIN_STOP_TRANSFER_REQ), 1);
	}

	/* flush all queued data */
	pkt_clear(garmin_data_p);

	spin_lock_irqsave(&garmin_data_p->lock, flags);
	garmin_data_p->insize = 0;
	garmin_data_p->outsize = 0;
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);

	return status;
}






static int garmin_init_session(struct usb_serial_port *port)
{
	unsigned long flags;
	struct usb_serial *serial = port->serial;
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
	int status = 0;

	if (status == 0) {
		usb_kill_urb(port->interrupt_in_urb);

		dbg("%s - adding interrupt input", __func__);
		port->interrupt_in_urb->dev = serial->dev;
		status = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
		if (status)
			dev_err(&serial->dev->dev,
			  "%s - failed submitting interrupt urb, error %d\n",
							__func__, status);
	}

	if (status == 0) {
		dbg("%s - starting session ...", __func__);
		garmin_data_p->state = STATE_ACTIVE;
		status = garmin_write_bulk(port, GARMIN_START_SESSION_REQ,
					sizeof(GARMIN_START_SESSION_REQ), 0);

		if (status >= 0) {

			spin_lock_irqsave(&garmin_data_p->lock, flags);
			garmin_data_p->ignorePkts++;
			spin_unlock_irqrestore(&garmin_data_p->lock, flags);

			/* not needed, but the win32 driver does it too ... */
			status = garmin_write_bulk(port,
					GARMIN_START_SESSION_REQ2,
					sizeof(GARMIN_START_SESSION_REQ2), 0);
			if (status >= 0) {
				status = 0;
				spin_lock_irqsave(&garmin_data_p->lock, flags);
				garmin_data_p->ignorePkts++;
				spin_unlock_irqrestore(&garmin_data_p->lock,
									flags);
			}
		}
	}

	return status;
}





static int garmin_open(struct tty_struct *tty,
			struct usb_serial_port *port, struct file *filp)
{
	unsigned long flags;
	int status = 0;
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);

	dbg("%s - port %d", __func__, port->number);

	/*
	 * Force low_latency on so that our tty_push actually forces the data
	 * through, otherwise it is scheduled, and with high data rates (like
	 * with OHCI) data can get lost.
	 */
	if (tty)
		tty->low_latency = 1;

	spin_lock_irqsave(&garmin_data_p->lock, flags);
	garmin_data_p->mode  = initial_mode;
	garmin_data_p->count = 0;
	garmin_data_p->flags = 0;
	atomic_set(&garmin_data_p->req_count, 0);
	atomic_set(&garmin_data_p->resp_count, 0);
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);

	/* shutdown any bulk reads that might be going on */
	usb_kill_urb(port->write_urb);
	usb_kill_urb(port->read_urb);

	if (garmin_data_p->state == STATE_RESET)
		status = garmin_init_session(port);

	garmin_data_p->state = STATE_ACTIVE;
	return status;
}


static void garmin_close(struct tty_struct *tty,
			struct usb_serial_port *port, struct file *filp)
{
	struct usb_serial *serial = port->serial;
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);

	dbg("%s - port %d - mode=%d state=%d flags=0x%X", __func__,
		port->number, garmin_data_p->mode,
		garmin_data_p->state, garmin_data_p->flags);

	if (!serial)
		return;

	mutex_lock(&port->serial->disc_mutex);
	if (!port->serial->disconnected)
		garmin_clear(garmin_data_p);

	/* shutdown our urbs */
	usb_kill_urb(port->read_urb);
	usb_kill_urb(port->write_urb);

	if (!port->serial->disconnected) {
		if (noResponseFromAppLayer(garmin_data_p) ||
		    ((garmin_data_p->flags & CLEAR_HALT_REQUIRED) != 0)) {
			process_resetdev_request(port);
			garmin_data_p->state = STATE_RESET;
		} else {
			garmin_data_p->state = STATE_DISCONNECTED;
		}
	} else {
		garmin_data_p->state = STATE_DISCONNECTED;
	}
	mutex_unlock(&port->serial->disc_mutex);
}

static void garmin_write_bulk_callback(struct urb *urb)
{
	unsigned long flags;
	struct usb_serial_port *port = urb->context;
	int status = urb->status;

	if (port) {
		struct garmin_data *garmin_data_p =
					usb_get_serial_port_data(port);

		dbg("%s - port %d", __func__, port->number);

		if (GARMIN_LAYERID_APPL == getLayerId(urb->transfer_buffer)
		    && (garmin_data_p->mode == MODE_GARMIN_SERIAL))  {
			gsp_send_ack(garmin_data_p,
					((__u8 *)urb->transfer_buffer)[4]);
		}

		if (status) {
			dbg("%s - nonzero write bulk status received: %d",
			    __func__, urb->status);
			spin_lock_irqsave(&garmin_data_p->lock, flags);
			garmin_data_p->flags |= CLEAR_HALT_REQUIRED;
			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
		}

		usb_serial_port_softint(port);
	}

	/* Ignore errors that resulted from garmin_write_bulk with
	   dismiss_ack = 1 */

	/* free up the transfer buffer, as usb_free_urb() does not do this */
	kfree(urb->transfer_buffer);
}


static int garmin_write_bulk(struct usb_serial_port *port,
			      const unsigned char *buf, int count,
			      int dismiss_ack)
{
	unsigned long flags;
	struct usb_serial *serial = port->serial;
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
	struct urb *urb;
	unsigned char *buffer;
	int status;

	dbg("%s - port %d, state %d", __func__, port->number,
		garmin_data_p->state);

	spin_lock_irqsave(&garmin_data_p->lock, flags);
	garmin_data_p->flags &= ~FLAGS_DROP_DATA;
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);

	buffer = kmalloc(count, GFP_ATOMIC);
	if (!buffer) {
		dev_err(&port->dev, "out of memory\n");
		return -ENOMEM;
	}

	urb = usb_alloc_urb(0, GFP_ATOMIC);
	if (!urb) {
		dev_err(&port->dev, "no more free urbs\n");
		kfree(buffer);
		return -ENOMEM;
	}

	memcpy(buffer, buf, count);

	usb_serial_debug_data(debug, &port->dev, __func__, count, buffer);

	usb_fill_bulk_urb(urb, serial->dev,
				usb_sndbulkpipe(serial->dev,
					port->bulk_out_endpointAddress),
				buffer, count,
				garmin_write_bulk_callback,
				dismiss_ack ? NULL : port);
	urb->transfer_flags |= URB_ZERO_PACKET;

	if (GARMIN_LAYERID_APPL == getLayerId(buffer)) {
		atomic_inc(&garmin_data_p->req_count);
		if (garmin_data_p->mode == MODE_GARMIN_SERIAL)  {
			pkt_clear(garmin_data_p);
			garmin_data_p->state = STATE_GSP_WAIT_DATA;
		}
	}

	/* send it down the pipe */
	status = usb_submit_urb(urb, GFP_ATOMIC);
	if (status) {
		dev_err(&port->dev,
		   "%s - usb_submit_urb(write bulk) failed with status = %d\n",
				__func__, status);
		count = status;
	}

	/* we are done with this urb, so let the host driver
	 * really free it when it is finished with it */
	usb_free_urb(urb);

	return count;
}

static int garmin_write(struct tty_struct *tty, struct usb_serial_port *port,
					 const unsigned char *buf, int count)
{
	int pktid, pktsiz, len;
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
	__le32 *privpkt = (__le32 *)garmin_data_p->privpkt;

	usb_serial_debug_data(debug, &port->dev, __func__, count, buf);

	/* check for our private packets */
	if (count >= GARMIN_PKTHDR_LENGTH) {
		len = PRIVPKTSIZ;
		if (count < len)
			len = count;

		memcpy(garmin_data_p->privpkt, buf, len);

		pktsiz = getDataLength(garmin_data_p->privpkt);
		pktid  = getPacketId(garmin_data_p->privpkt);

		if (count == (GARMIN_PKTHDR_LENGTH+pktsiz)
		    && GARMIN_LAYERID_PRIVATE ==
				getLayerId(garmin_data_p->privpkt)) {

			dbg("%s - processing private request %d",
				__func__, pktid);

			/* drop all unfinished transfers */
			garmin_clear(garmin_data_p);

			switch (pktid) {

			case PRIV_PKTID_SET_DEBUG:
				if (pktsiz != 4)
					return -EINVPKT;
				debug = __le32_to_cpu(privpkt[3]);
				dbg("%s - debug level set to 0x%X",
					__func__, debug);
				break;

			case PRIV_PKTID_SET_MODE:
				if (pktsiz != 4)
					return -EINVPKT;
				garmin_data_p->mode = __le32_to_cpu(privpkt[3]);
				dbg("%s - mode set to %d",
					__func__, garmin_data_p->mode);
				break;

			case PRIV_PKTID_INFO_REQ:
				priv_status_resp(port);
				break;

			case PRIV_PKTID_RESET_REQ:
				atomic_inc(&garmin_data_p->req_count);
				break;

			case PRIV_PKTID_SET_DEF_MODE:
				if (pktsiz != 4)
					return -EINVPKT;
				initial_mode = __le32_to_cpu(privpkt[3]);
				dbg("%s - initial_mode set to %d",
					__func__,
					garmin_data_p->mode);
				break;
			}
			return count;
		}
	}

	garmin_data_p->ignorePkts = 0;

	if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
		return gsp_receive(garmin_data_p, buf, count);
	} else {	/* MODE_NATIVE */
		return nat_receive(garmin_data_p, buf, count);
	}
}


static int garmin_write_room(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	/*
	 * Report back the bytes currently available in the output buffer.
	 */
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
	return GPS_OUT_BUFSIZ-garmin_data_p->outsize;
}


static void garmin_read_process(struct garmin_data *garmin_data_p,
				 unsigned char *data, unsigned data_length)
{
	if (garmin_data_p->flags & FLAGS_DROP_DATA) {
		/* abort-transfer cmd is actice */
		dbg("%s - pkt dropped", __func__);
	} else if (garmin_data_p->state != STATE_DISCONNECTED &&
		garmin_data_p->state != STATE_RESET) {

		/* remember any appl.layer packets, so we know
		   if a reset is required or not when closing
		   the device */
		if (0 == memcmp(data, GARMIN_APP_LAYER_REPLY,
				sizeof(GARMIN_APP_LAYER_REPLY))) {
			atomic_inc(&garmin_data_p->resp_count);
		}

		/* if throttling is active or postprecessing is required
		   put the received data in the input queue, otherwise
		   send it directly to the tty port */
		if (garmin_data_p->flags & FLAGS_QUEUING) {
			pkt_add(garmin_data_p, data, data_length);
		} else if (garmin_data_p->mode == MODE_GARMIN_SERIAL) {
			if (getLayerId(data) == GARMIN_LAYERID_APPL)
				pkt_add(garmin_data_p, data, data_length);
		} else {
			send_to_tty(garmin_data_p->port, data, data_length);
		}
	}
}


static void garmin_read_bulk_callback(struct urb *urb)
{
	unsigned long flags;
	struct usb_serial_port *port = urb->context;
	struct usb_serial *serial =  port->serial;
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
	unsigned char *data = urb->transfer_buffer;
	int status = urb->status;
	int retval;

	dbg("%s - port %d", __func__, port->number);

	if (!serial) {
		dbg("%s - bad serial pointer, exiting", __func__);
		return;
	}

	if (status) {
		dbg("%s - nonzero read bulk status received: %d",
			__func__, status);
		return;
	}

	usb_serial_debug_data(debug, &port->dev,
				__func__, urb->actual_length, data);

	garmin_read_process(garmin_data_p, data, urb->actual_length);

	if (urb->actual_length == 0 &&
			0 != (garmin_data_p->flags & FLAGS_BULK_IN_RESTART)) {
		spin_lock_irqsave(&garmin_data_p->lock, flags);
		garmin_data_p->flags &= ~FLAGS_BULK_IN_RESTART;
		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
		retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
		if (retval)
			dev_err(&port->dev,
				"%s - failed resubmitting read urb, error %d\n",
				__func__, retval);
	} else if (urb->actual_length > 0) {
		/* Continue trying to read until nothing more is received  */
		if (0 == (garmin_data_p->flags & FLAGS_THROTTLED)) {
			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
			if (retval)
				dev_err(&port->dev,
					"%s - failed resubmitting read urb, "
					"error %d\n", __func__, retval);
		}
	} else {
		dbg("%s - end of bulk data", __func__);
		spin_lock_irqsave(&garmin_data_p->lock, flags);
		garmin_data_p->flags &= ~FLAGS_BULK_IN_ACTIVE;
		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
	}
	return;
}


static void garmin_read_int_callback(struct urb *urb)
{
	unsigned long flags;
	int retval;
	struct usb_serial_port *port = urb->context;
	struct usb_serial *serial = port->serial;
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
	unsigned char *data = urb->transfer_buffer;
	int status = urb->status;

	switch (status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dbg("%s - urb shutting down with status: %d",
			__func__, status);
		return;
	default:
		dbg("%s - nonzero urb status received: %d",
			__func__, status);
		return;
	}

	usb_serial_debug_data(debug, &port->dev, __func__,
				urb->actual_length, urb->transfer_buffer);

	if (urb->actual_length == sizeof(GARMIN_BULK_IN_AVAIL_REPLY) &&
	    0 == memcmp(data, GARMIN_BULK_IN_AVAIL_REPLY,
				sizeof(GARMIN_BULK_IN_AVAIL_REPLY))) {

		dbg("%s - bulk data available.", __func__);

		if (0 == (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {

			/* bulk data available */
			usb_fill_bulk_urb(port->read_urb, serial->dev,
					usb_rcvbulkpipe(serial->dev,
						port->bulk_in_endpointAddress),
					port->read_urb->transfer_buffer,
					port->read_urb->transfer_buffer_length,
					garmin_read_bulk_callback, port);
			retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
			if (retval) {
				dev_err(&port->dev,
				 "%s - failed submitting read urb, error %d\n",
							__func__, retval);
			} else {
				spin_lock_irqsave(&garmin_data_p->lock, flags);
				garmin_data_p->flags |= FLAGS_BULK_IN_ACTIVE;
				/* do not send this packet to the user */
				garmin_data_p->ignorePkts = 1;
				spin_unlock_irqrestore(&garmin_data_p->lock,
									flags);
			}
		} else {
			/* bulk-in transfer still active */
			spin_lock_irqsave(&garmin_data_p->lock, flags);
			garmin_data_p->flags |= FLAGS_BULK_IN_RESTART;
			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
		}

	} else if (urb->actual_length == (4+sizeof(GARMIN_START_SESSION_REPLY))
			 && 0 == memcmp(data, GARMIN_START_SESSION_REPLY,
					sizeof(GARMIN_START_SESSION_REPLY))) {

		spin_lock_irqsave(&garmin_data_p->lock, flags);
		garmin_data_p->flags |= FLAGS_SESSION_REPLY1_SEEN;
		spin_unlock_irqrestore(&garmin_data_p->lock, flags);

		/* save the serial number */
		garmin_data_p->serial_num = __le32_to_cpup(
					(__le32 *)(data+GARMIN_PKTHDR_LENGTH));

		dbg("%s - start-of-session reply seen - serial %u.",
			__func__, garmin_data_p->serial_num);
	}

	if (garmin_data_p->ignorePkts) {
		/* this reply belongs to a request generated by the driver,
		   ignore it. */
		dbg("%s - pkt ignored (%d)",
			__func__, garmin_data_p->ignorePkts);
		spin_lock_irqsave(&garmin_data_p->lock, flags);
		garmin_data_p->ignorePkts--;
		spin_unlock_irqrestore(&garmin_data_p->lock, flags);
	} else {
		garmin_read_process(garmin_data_p, data, urb->actual_length);
	}

	port->interrupt_in_urb->dev = port->serial->dev;
	retval = usb_submit_urb(urb, GFP_ATOMIC);
	if (retval)
		dev_err(&urb->dev->dev,
			"%s - Error %d submitting interrupt urb\n",
			__func__, retval);
}


/*
 * Sends the next queued packt to the tty port (garmin native mode only)
 * and then sets a timer to call itself again until all queued data
 * is sent.
 */
static int garmin_flush_queue(struct garmin_data *garmin_data_p)
{
	unsigned long flags;
	struct garmin_packet *pkt;

	if ((garmin_data_p->flags & FLAGS_THROTTLED) == 0) {
		pkt = pkt_pop(garmin_data_p);
		if (pkt != NULL) {
			send_to_tty(garmin_data_p->port, pkt->data, pkt->size);
			kfree(pkt);
			mod_timer(&garmin_data_p->timer, (1)+jiffies);

		} else {
			spin_lock_irqsave(&garmin_data_p->lock, flags);
			garmin_data_p->flags &= ~FLAGS_QUEUING;
			spin_unlock_irqrestore(&garmin_data_p->lock, flags);
		}
	}
	return 0;
}


static void garmin_throttle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
	unsigned long flags;

	dbg("%s - port %d", __func__, port->number);
	/* set flag, data received will be put into a queue
	   for later processing */
	spin_lock_irqsave(&garmin_data_p->lock, flags);
	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
}


static void garmin_unthrottle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
	unsigned long flags;
	int status;

	dbg("%s - port %d", __func__, port->number);
	spin_lock_irqsave(&garmin_data_p->lock, flags);
	garmin_data_p->flags &= ~FLAGS_THROTTLED;
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);

	/* in native mode send queued data to tty, in
	   serial mode nothing needs to be done here */
	if (garmin_data_p->mode == MODE_NATIVE)
		garmin_flush_queue(garmin_data_p);

	if (0 != (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
		status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
		if (status)
			dev_err(&port->dev,
				"%s - failed resubmitting read urb, error %d\n",
				__func__, status);
	}
}

/*
 * The timer is currently only used to send queued packets to
 * the tty in cases where the protocol provides no own handshaking
 * to initiate the transfer.
 */
static void timeout_handler(unsigned long data)
{
	struct garmin_data *garmin_data_p = (struct garmin_data *) data;

	/* send the next queued packet to the tty port */
	if (garmin_data_p->mode == MODE_NATIVE)
		if (garmin_data_p->flags & FLAGS_QUEUING)
			garmin_flush_queue(garmin_data_p);
}



static int garmin_attach(struct usb_serial *serial)
{
	int status = 0;
	struct usb_serial_port *port = serial->port[0];
	struct garmin_data *garmin_data_p = NULL;

	dbg("%s", __func__);

	garmin_data_p = kzalloc(sizeof(struct garmin_data), GFP_KERNEL);
	if (garmin_data_p == NULL) {
		dev_err(&port->dev, "%s - Out of memory\n", __func__);
		return -ENOMEM;
	}
	init_timer(&garmin_data_p->timer);
	spin_lock_init(&garmin_data_p->lock);
	INIT_LIST_HEAD(&garmin_data_p->pktlist);
	/* garmin_data_p->timer.expires = jiffies + session_timeout; */
	garmin_data_p->timer.data = (unsigned long)garmin_data_p;
	garmin_data_p->timer.function = timeout_handler;
	garmin_data_p->port = port;
	garmin_data_p->state = 0;
	garmin_data_p->count = 0;
	usb_set_serial_port_data(port, garmin_data_p);

	status = garmin_init_session(port);

	return status;
}


static void garmin_shutdown(struct usb_serial *serial)
{
	struct usb_serial_port *port = serial->port[0];
	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);

	dbg("%s", __func__);

	usb_kill_urb(port->interrupt_in_urb);
	del_timer_sync(&garmin_data_p->timer);
	kfree(garmin_data_p);
	usb_set_serial_port_data(port, NULL);
}


/* All of the device info needed */
static struct usb_serial_driver garmin_device = {
	.driver = {
		.owner       = THIS_MODULE,
		.name        = "garmin_gps",
	},
	.description         = "Garmin GPS usb/tty",
	.usb_driver          = &garmin_driver,
	.id_table            = id_table,
	.num_ports           = 1,
	.open                = garmin_open,
	.close               = garmin_close,
	.throttle            = garmin_throttle,
	.unthrottle          = garmin_unthrottle,
	.attach              = garmin_attach,
	.shutdown            = garmin_shutdown,
	.write               = garmin_write,
	.write_room          = garmin_write_room,
	.write_bulk_callback = garmin_write_bulk_callback,
	.read_bulk_callback  = garmin_read_bulk_callback,
	.read_int_callback   = garmin_read_int_callback,
};



static int __init garmin_init(void)
{
	int retval;

	retval = usb_serial_register(&garmin_device);
	if (retval)
		goto failed_garmin_register;
	retval = usb_register(&garmin_driver);
	if (retval)
		goto failed_usb_register;
	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
	       DRIVER_DESC "\n");

	return 0;
failed_usb_register:
	usb_serial_deregister(&garmin_device);
failed_garmin_register:
	return retval;
}


static void __exit garmin_exit(void)
{
	usb_deregister(&garmin_driver);
	usb_serial_deregister(&garmin_device);
}




module_init(garmin_init);
module_exit(garmin_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

module_param(debug, bool, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(debug, "Debug enabled or not");
module_param(initial_mode, int, S_IRUGO);
MODULE_PARM_DESC(initial_mode, "Initial mode");

OpenPOWER on IntegriCloud