summaryrefslogtreecommitdiff
path: root/drivers/usb/serial/usb-serial.c
blob: e7e29c797824fc3b93c97cccb0643604ed31f651 (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
/*
 * USB Serial Converter driver
 *
 * Copyright (C) 2009 - 2013 Johan Hovold (jhovold@gmail.com)
 * Copyright (C) 1999 - 2012 Greg Kroah-Hartman (greg@kroah.com)
 * Copyright (C) 2000 Peter Berger (pberger@brimson.com)
 * Copyright (C) 2000 Al Borchers (borchers@steinerpoint.com)
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License version
 *	2 as published by the Free Software Foundation.
 *
 * This driver was originally based on the ACM driver by Armin Fuerst (which was
 * based on a driver by Brad Keryan)
 *
 * See Documentation/usb/usb-serial.txt for more information on using this
 * driver
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/uaccess.h>
#include <linux/serial.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/kfifo.h>
#include <linux/idr.h>
#include "pl2303.h"

#define DRIVER_AUTHOR "Greg Kroah-Hartman <gregkh@linuxfoundation.org>"
#define DRIVER_DESC "USB Serial Driver core"

#define USB_SERIAL_TTY_MAJOR	188
#define USB_SERIAL_TTY_MINORS	512	/* should be enough for a while */

/* There is no MODULE_DEVICE_TABLE for usbserial.c.  Instead
   the MODULE_DEVICE_TABLE declarations in each serial driver
   cause the "hotplug" program to pull in whatever module is necessary
   via modprobe, and modprobe will load usbserial because the serial
   drivers depend on it.
*/

static DEFINE_IDR(serial_minors);
static DEFINE_MUTEX(table_lock);
static LIST_HEAD(usb_serial_driver_list);

/*
 * Look up the serial port structure.  If it is found and it hasn't been
 * disconnected, return with the parent usb_serial structure's disc_mutex held
 * and its refcount incremented.  Otherwise return NULL.
 */
struct usb_serial_port *usb_serial_port_get_by_minor(unsigned minor)
{
	struct usb_serial *serial;
	struct usb_serial_port *port;

	mutex_lock(&table_lock);
	port = idr_find(&serial_minors, minor);
	if (!port)
		goto exit;

	serial = port->serial;
	mutex_lock(&serial->disc_mutex);
	if (serial->disconnected) {
		mutex_unlock(&serial->disc_mutex);
		port = NULL;
	} else {
		kref_get(&serial->kref);
	}
exit:
	mutex_unlock(&table_lock);
	return port;
}

static int allocate_minors(struct usb_serial *serial, int num_ports)
{
	struct usb_serial_port *port;
	unsigned int i, j;
	int minor;

	dev_dbg(&serial->interface->dev, "%s %d\n", __func__, num_ports);

	mutex_lock(&table_lock);
	for (i = 0; i < num_ports; ++i) {
		port = serial->port[i];
		minor = idr_alloc(&serial_minors, port, 0, 0, GFP_KERNEL);
		if (minor < 0)
			goto error;
		port->minor = minor;
		port->port_number = i;
	}
	serial->minors_reserved = 1;
	mutex_unlock(&table_lock);
	return 0;
error:
	/* unwind the already allocated minors */
	for (j = 0; j < i; ++j)
		idr_remove(&serial_minors, serial->port[j]->minor);
	mutex_unlock(&table_lock);
	return minor;
}

static void release_minors(struct usb_serial *serial)
{
	int i;

	mutex_lock(&table_lock);
	for (i = 0; i < serial->num_ports; ++i)
		idr_remove(&serial_minors, serial->port[i]->minor);
	mutex_unlock(&table_lock);
	serial->minors_reserved = 0;
}

static void destroy_serial(struct kref *kref)
{
	struct usb_serial *serial;
	struct usb_serial_port *port;
	int i;

	serial = to_usb_serial(kref);

	/* return the minor range that this device had */
	if (serial->minors_reserved)
		release_minors(serial);

	if (serial->attached && serial->type->release)
		serial->type->release(serial);

	/* Now that nothing is using the ports, they can be freed */
	for (i = 0; i < serial->num_port_pointers; ++i) {
		port = serial->port[i];
		if (port) {
			port->serial = NULL;
			put_device(&port->dev);
		}
	}

	usb_put_intf(serial->interface);
	usb_put_dev(serial->dev);
	kfree(serial);
}

void usb_serial_put(struct usb_serial *serial)
{
	kref_put(&serial->kref, destroy_serial);
}

/*****************************************************************************
 * Driver tty interface functions
 *****************************************************************************/

/**
 * serial_install - install tty
 * @driver: the driver (USB in our case)
 * @tty: the tty being created
 *
 * Create the termios objects for this tty.  We use the default
 * USB serial settings but permit them to be overridden by
 * serial->type->init_termios.
 *
 * This is the first place a new tty gets used.  Hence this is where we
 * acquire references to the usb_serial structure and the driver module,
 * where we store a pointer to the port, and where we do an autoresume.
 * All these actions are reversed in serial_cleanup().
 */
static int serial_install(struct tty_driver *driver, struct tty_struct *tty)
{
	int idx = tty->index;
	struct usb_serial *serial;
	struct usb_serial_port *port;
	int retval = -ENODEV;

	port = usb_serial_port_get_by_minor(idx);
	if (!port)
		return retval;

	serial = port->serial;
	if (!try_module_get(serial->type->driver.owner))
		goto error_module_get;

	retval = usb_autopm_get_interface(serial->interface);
	if (retval)
		goto error_get_interface;

	retval = tty_port_install(&port->port, driver, tty);
	if (retval)
		goto error_init_termios;

	mutex_unlock(&serial->disc_mutex);

	/* allow the driver to update the settings */
	if (serial->type->init_termios)
		serial->type->init_termios(tty);

	tty->driver_data = port;

	return retval;

 error_init_termios:
	usb_autopm_put_interface(serial->interface);
 error_get_interface:
	module_put(serial->type->driver.owner);
 error_module_get:
	usb_serial_put(serial);
	mutex_unlock(&serial->disc_mutex);
	return retval;
}

static int serial_port_activate(struct tty_port *tport, struct tty_struct *tty)
{
	struct usb_serial_port *port =
		container_of(tport, struct usb_serial_port, port);
	struct usb_serial *serial = port->serial;
	int retval;

	mutex_lock(&serial->disc_mutex);
	if (serial->disconnected)
		retval = -ENODEV;
	else
		retval = port->serial->type->open(tty, port);
	mutex_unlock(&serial->disc_mutex);

	if (retval < 0)
		retval = usb_translate_errors(retval);

	return retval;
}

static int serial_open(struct tty_struct *tty, struct file *filp)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	return tty_port_open(&port->port, tty, filp);
}

/**
 * serial_port_shutdown - shut down hardware
 * @tport: tty port to shut down
 *
 * Shut down a USB serial port. Serialized against activate by the
 * tport mutex and kept to matching open/close pairs
 * of calls by the ASYNCB_INITIALIZED flag.
 *
 * Not called if tty is console.
 */
static void serial_port_shutdown(struct tty_port *tport)
{
	struct usb_serial_port *port =
		container_of(tport, struct usb_serial_port, port);
	struct usb_serial_driver *drv = port->serial->type;

	if (drv->close)
		drv->close(port);
}

static void serial_hangup(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	tty_port_hangup(&port->port);
}

static void serial_close(struct tty_struct *tty, struct file *filp)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	tty_port_close(&port->port, tty, filp);
}

/**
 * serial_cleanup - free resources post close/hangup
 * @port: port to free up
 *
 * Do the resource freeing and refcount dropping for the port.
 * Avoid freeing the console.
 *
 * Called asynchronously after the last tty kref is dropped.
 */
static void serial_cleanup(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct usb_serial *serial;
	struct module *owner;

	dev_dbg(tty->dev, "%s\n", __func__);

	/* The console is magical.  Do not hang up the console hardware
	 * or there will be tears.
	 */
	if (port->port.console)
		return;

	tty->driver_data = NULL;

	serial = port->serial;
	owner = serial->type->driver.owner;

	mutex_lock(&serial->disc_mutex);
	if (!serial->disconnected)
		usb_autopm_put_interface(serial->interface);
	mutex_unlock(&serial->disc_mutex);

	usb_serial_put(serial);
	module_put(owner);
}

static int serial_write(struct tty_struct *tty, const unsigned char *buf,
								int count)
{
	struct usb_serial_port *port = tty->driver_data;
	int retval = -ENODEV;

	if (port->serial->dev->state == USB_STATE_NOTATTACHED)
		goto exit;

	dev_dbg(tty->dev, "%s - %d byte(s)\n", __func__, count);

	retval = port->serial->type->write(tty, port, buf, count);
	if (retval < 0)
		retval = usb_translate_errors(retval);
exit:
	return retval;
}

static int serial_write_room(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	return port->serial->type->write_room(tty);
}

static int serial_chars_in_buffer(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct usb_serial *serial = port->serial;

	dev_dbg(tty->dev, "%s\n", __func__);

	if (serial->disconnected)
		return 0;

	return serial->type->chars_in_buffer(tty);
}

static void serial_wait_until_sent(struct tty_struct *tty, int timeout)
{
	struct usb_serial_port *port = tty->driver_data;
	struct usb_serial *serial = port->serial;

	dev_dbg(tty->dev, "%s\n", __func__);

	if (!port->serial->type->wait_until_sent)
		return;

	mutex_lock(&serial->disc_mutex);
	if (!serial->disconnected)
		port->serial->type->wait_until_sent(tty, timeout);
	mutex_unlock(&serial->disc_mutex);
}

static void serial_throttle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	if (port->serial->type->throttle)
		port->serial->type->throttle(tty);
}

static void serial_unthrottle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	if (port->serial->type->unthrottle)
		port->serial->type->unthrottle(tty);
}

static int serial_ioctl(struct tty_struct *tty,
					unsigned int cmd, unsigned long arg)
{
	struct usb_serial_port *port = tty->driver_data;
	int retval = -ENOIOCTLCMD;

	dev_dbg(tty->dev, "%s - cmd 0x%04x\n", __func__, cmd);

	switch (cmd) {
	case TIOCMIWAIT:
		if (port->serial->type->tiocmiwait)
			retval = port->serial->type->tiocmiwait(tty, arg);
		break;
	default:
		if (port->serial->type->ioctl)
			retval = port->serial->type->ioctl(tty, cmd, arg);
	}

	return retval;
}

static void serial_set_termios(struct tty_struct *tty, struct ktermios *old)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	if (port->serial->type->set_termios)
		port->serial->type->set_termios(tty, port, old);
	else
		tty_termios_copy_hw(&tty->termios, old);
}

static int serial_break(struct tty_struct *tty, int break_state)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	if (port->serial->type->break_ctl)
		port->serial->type->break_ctl(tty, break_state);

	return 0;
}

static int serial_proc_show(struct seq_file *m, void *v)
{
	struct usb_serial *serial;
	struct usb_serial_port *port;
	int i;
	char tmp[40];

	seq_puts(m, "usbserinfo:1.0 driver:2.0\n");
	for (i = 0; i < USB_SERIAL_TTY_MINORS; ++i) {
		port = usb_serial_port_get_by_minor(i);
		if (port == NULL)
			continue;
		serial = port->serial;

		seq_printf(m, "%d:", i);
		if (serial->type->driver.owner)
			seq_printf(m, " module:%s",
				module_name(serial->type->driver.owner));
		seq_printf(m, " name:\"%s\"",
				serial->type->description);
		seq_printf(m, " vendor:%04x product:%04x",
			le16_to_cpu(serial->dev->descriptor.idVendor),
			le16_to_cpu(serial->dev->descriptor.idProduct));
		seq_printf(m, " num_ports:%d", serial->num_ports);
		seq_printf(m, " port:%d", port->port_number);
		usb_make_path(serial->dev, tmp, sizeof(tmp));
		seq_printf(m, " path:%s", tmp);

		seq_putc(m, '\n');
		usb_serial_put(serial);
		mutex_unlock(&serial->disc_mutex);
	}
	return 0;
}

static int serial_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, serial_proc_show, NULL);
}

static const struct file_operations serial_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= serial_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static int serial_tiocmget(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	if (port->serial->type->tiocmget)
		return port->serial->type->tiocmget(tty);
	return -EINVAL;
}

static int serial_tiocmset(struct tty_struct *tty,
			    unsigned int set, unsigned int clear)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	if (port->serial->type->tiocmset)
		return port->serial->type->tiocmset(tty, set, clear);
	return -EINVAL;
}

static int serial_get_icount(struct tty_struct *tty,
				struct serial_icounter_struct *icount)
{
	struct usb_serial_port *port = tty->driver_data;

	dev_dbg(tty->dev, "%s\n", __func__);

	if (port->serial->type->get_icount)
		return port->serial->type->get_icount(tty, icount);
	return -EINVAL;
}

/*
 * We would be calling tty_wakeup here, but unfortunately some line
 * disciplines have an annoying habit of calling tty->write from
 * the write wakeup callback (e.g. n_hdlc.c).
 */
void usb_serial_port_softint(struct usb_serial_port *port)
{
	schedule_work(&port->work);
}
EXPORT_SYMBOL_GPL(usb_serial_port_softint);

static void usb_serial_port_work(struct work_struct *work)
{
	struct usb_serial_port *port =
		container_of(work, struct usb_serial_port, work);

	tty_port_tty_wakeup(&port->port);
}

static void usb_serial_port_poison_urbs(struct usb_serial_port *port)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
		usb_poison_urb(port->read_urbs[i]);
	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
		usb_poison_urb(port->write_urbs[i]);

	usb_poison_urb(port->interrupt_in_urb);
	usb_poison_urb(port->interrupt_out_urb);
}

static void usb_serial_port_unpoison_urbs(struct usb_serial_port *port)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
		usb_unpoison_urb(port->read_urbs[i]);
	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
		usb_unpoison_urb(port->write_urbs[i]);

	usb_unpoison_urb(port->interrupt_in_urb);
	usb_unpoison_urb(port->interrupt_out_urb);
}

static void usb_serial_port_release(struct device *dev)
{
	struct usb_serial_port *port = to_usb_serial_port(dev);
	int i;

	dev_dbg(dev, "%s\n", __func__);

	usb_free_urb(port->interrupt_in_urb);
	usb_free_urb(port->interrupt_out_urb);
	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
		usb_free_urb(port->read_urbs[i]);
		kfree(port->bulk_in_buffers[i]);
	}
	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) {
		usb_free_urb(port->write_urbs[i]);
		kfree(port->bulk_out_buffers[i]);
	}
	kfifo_free(&port->write_fifo);
	kfree(port->interrupt_in_buffer);
	kfree(port->interrupt_out_buffer);
	tty_port_destroy(&port->port);
	kfree(port);
}

static struct usb_serial *create_serial(struct usb_device *dev,
					struct usb_interface *interface,
					struct usb_serial_driver *driver)
{
	struct usb_serial *serial;

	serial = kzalloc(sizeof(*serial), GFP_KERNEL);
	if (!serial)
		return NULL;
	serial->dev = usb_get_dev(dev);
	serial->type = driver;
	serial->interface = usb_get_intf(interface);
	kref_init(&serial->kref);
	mutex_init(&serial->disc_mutex);
	serial->minors_reserved = 0;

	return serial;
}

static const struct usb_device_id *match_dynamic_id(struct usb_interface *intf,
					    struct usb_serial_driver *drv)
{
	struct usb_dynid *dynid;

	spin_lock(&drv->dynids.lock);
	list_for_each_entry(dynid, &drv->dynids.list, node) {
		if (usb_match_one_id(intf, &dynid->id)) {
			spin_unlock(&drv->dynids.lock);
			return &dynid->id;
		}
	}
	spin_unlock(&drv->dynids.lock);
	return NULL;
}

static const struct usb_device_id *get_iface_id(struct usb_serial_driver *drv,
						struct usb_interface *intf)
{
	const struct usb_device_id *id;

	id = usb_match_id(intf, drv->id_table);
	if (id) {
		dev_dbg(&intf->dev, "static descriptor matches\n");
		goto exit;
	}
	id = match_dynamic_id(intf, drv);
	if (id)
		dev_dbg(&intf->dev, "dynamic descriptor matches\n");
exit:
	return id;
}

/* Caller must hold table_lock */
static struct usb_serial_driver *search_serial_device(
					struct usb_interface *iface)
{
	const struct usb_device_id *id = NULL;
	struct usb_serial_driver *drv;
	struct usb_driver *driver = to_usb_driver(iface->dev.driver);

	/* Check if the usb id matches a known device */
	list_for_each_entry(drv, &usb_serial_driver_list, driver_list) {
		if (drv->usb_driver == driver)
			id = get_iface_id(drv, iface);
		if (id)
			return drv;
	}

	return NULL;
}

static int serial_port_carrier_raised(struct tty_port *port)
{
	struct usb_serial_port *p = container_of(port, struct usb_serial_port, port);
	struct usb_serial_driver *drv = p->serial->type;

	if (drv->carrier_raised)
		return drv->carrier_raised(p);
	/* No carrier control - don't block */
	return 1;
}

static void serial_port_dtr_rts(struct tty_port *port, int on)
{
	struct usb_serial_port *p = container_of(port, struct usb_serial_port, port);
	struct usb_serial_driver *drv = p->serial->type;

	if (drv->dtr_rts)
		drv->dtr_rts(p, on);
}

static ssize_t port_number_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct usb_serial_port *port = to_usb_serial_port(dev);

	return sprintf(buf, "%u\n", port->port_number);
}
static DEVICE_ATTR_RO(port_number);

static struct attribute *usb_serial_port_attrs[] = {
	&dev_attr_port_number.attr,
	NULL
};
ATTRIBUTE_GROUPS(usb_serial_port);

static const struct tty_port_operations serial_port_ops = {
	.carrier_raised		= serial_port_carrier_raised,
	.dtr_rts		= serial_port_dtr_rts,
	.activate		= serial_port_activate,
	.shutdown		= serial_port_shutdown,
};

static int usb_serial_probe(struct usb_interface *interface,
			       const struct usb_device_id *id)
{
	struct device *ddev = &interface->dev;
	struct usb_device *dev = interface_to_usbdev(interface);
	struct usb_serial *serial = NULL;
	struct usb_serial_port *port;
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	struct usb_endpoint_descriptor *interrupt_in_endpoint[MAX_NUM_PORTS];
	struct usb_endpoint_descriptor *interrupt_out_endpoint[MAX_NUM_PORTS];
	struct usb_endpoint_descriptor *bulk_in_endpoint[MAX_NUM_PORTS];
	struct usb_endpoint_descriptor *bulk_out_endpoint[MAX_NUM_PORTS];
	struct usb_serial_driver *type = NULL;
	int retval;
	int buffer_size;
	int i;
	int j;
	int num_interrupt_in = 0;
	int num_interrupt_out = 0;
	int num_bulk_in = 0;
	int num_bulk_out = 0;
	int num_ports = 0;
	int max_endpoints;

	mutex_lock(&table_lock);
	type = search_serial_device(interface);
	if (!type) {
		mutex_unlock(&table_lock);
		dev_dbg(ddev, "none matched\n");
		return -ENODEV;
	}

	if (!try_module_get(type->driver.owner)) {
		mutex_unlock(&table_lock);
		dev_err(ddev, "module get failed, exiting\n");
		return -EIO;
	}
	mutex_unlock(&table_lock);

	serial = create_serial(dev, interface, type);
	if (!serial) {
		module_put(type->driver.owner);
		return -ENOMEM;
	}

	/* if this device type has a probe function, call it */
	if (type->probe) {
		const struct usb_device_id *id;

		id = get_iface_id(type, interface);
		retval = type->probe(serial, id);

		if (retval) {
			dev_dbg(ddev, "sub driver rejected device\n");
			usb_serial_put(serial);
			module_put(type->driver.owner);
			return retval;
		}
	}

	/* descriptor matches, let's find the endpoints needed */
	/* check out the endpoints */
	iface_desc = interface->cur_altsetting;
	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
		endpoint = &iface_desc->endpoint[i].desc;

		if (usb_endpoint_is_bulk_in(endpoint)) {
			/* we found a bulk in endpoint */
			dev_dbg(ddev, "found bulk in on endpoint %d\n", i);
			if (num_bulk_in < MAX_NUM_PORTS) {
				bulk_in_endpoint[num_bulk_in] = endpoint;
				++num_bulk_in;
			}
		}

		if (usb_endpoint_is_bulk_out(endpoint)) {
			/* we found a bulk out endpoint */
			dev_dbg(ddev, "found bulk out on endpoint %d\n", i);
			if (num_bulk_out < MAX_NUM_PORTS) {
				bulk_out_endpoint[num_bulk_out] = endpoint;
				++num_bulk_out;
			}
		}

		if (usb_endpoint_is_int_in(endpoint)) {
			/* we found a interrupt in endpoint */
			dev_dbg(ddev, "found interrupt in on endpoint %d\n", i);
			if (num_interrupt_in < MAX_NUM_PORTS) {
				interrupt_in_endpoint[num_interrupt_in] =
						endpoint;
				++num_interrupt_in;
			}
		}

		if (usb_endpoint_is_int_out(endpoint)) {
			/* we found an interrupt out endpoint */
			dev_dbg(ddev, "found interrupt out on endpoint %d\n", i);
			if (num_interrupt_out < MAX_NUM_PORTS) {
				interrupt_out_endpoint[num_interrupt_out] =
						endpoint;
				++num_interrupt_out;
			}
		}
	}

#if defined(CONFIG_USB_SERIAL_PL2303) || defined(CONFIG_USB_SERIAL_PL2303_MODULE)
	/* BEGIN HORRIBLE HACK FOR PL2303 */
	/* this is needed due to the looney way its endpoints are set up */
	if (((le16_to_cpu(dev->descriptor.idVendor) == PL2303_VENDOR_ID) &&
	     (le16_to_cpu(dev->descriptor.idProduct) == PL2303_PRODUCT_ID)) ||
	    ((le16_to_cpu(dev->descriptor.idVendor) == ATEN_VENDOR_ID) &&
	     (le16_to_cpu(dev->descriptor.idProduct) == ATEN_PRODUCT_ID)) ||
	    ((le16_to_cpu(dev->descriptor.idVendor) == ALCOR_VENDOR_ID) &&
	     (le16_to_cpu(dev->descriptor.idProduct) == ALCOR_PRODUCT_ID)) ||
	    ((le16_to_cpu(dev->descriptor.idVendor) == SIEMENS_VENDOR_ID) &&
	     (le16_to_cpu(dev->descriptor.idProduct) == SIEMENS_PRODUCT_ID_EF81))) {
		if (interface != dev->actconfig->interface[0]) {
			/* check out the endpoints of the other interface*/
			iface_desc = dev->actconfig->interface[0]->cur_altsetting;
			for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
				endpoint = &iface_desc->endpoint[i].desc;
				if (usb_endpoint_is_int_in(endpoint)) {
					/* we found a interrupt in endpoint */
					dev_dbg(ddev, "found interrupt in for Prolific device on separate interface\n");
					if (num_interrupt_in < MAX_NUM_PORTS) {
						interrupt_in_endpoint[num_interrupt_in] = endpoint;
						++num_interrupt_in;
					}
				}
			}
		}

		/* Now make sure the PL-2303 is configured correctly.
		 * If not, give up now and hope this hack will work
		 * properly during a later invocation of usb_serial_probe
		 */
		if (num_bulk_in == 0 || num_bulk_out == 0) {
			dev_info(ddev, "PL-2303 hack: descriptors matched but endpoints did not\n");
			usb_serial_put(serial);
			module_put(type->driver.owner);
			return -ENODEV;
		}
	}
	/* END HORRIBLE HACK FOR PL2303 */
#endif

#ifdef CONFIG_USB_SERIAL_GENERIC
	if (type == &usb_serial_generic_device) {
		num_ports = num_bulk_out;
		if (num_ports == 0) {
			dev_err(ddev, "Generic device with no bulk out, not allowed.\n");
			usb_serial_put(serial);
			module_put(type->driver.owner);
			return -EIO;
		}
		dev_info(ddev, "The \"generic\" usb-serial driver is only for testing and one-off prototypes.\n");
		dev_info(ddev, "Tell linux-usb@vger.kernel.org to add your device to a proper driver.\n");
	}
#endif
	if (!num_ports) {
		/* if this device type has a calc_num_ports function, call it */
		if (type->calc_num_ports)
			num_ports = type->calc_num_ports(serial);
		if (!num_ports)
			num_ports = type->num_ports;
	}

	if (num_ports > MAX_NUM_PORTS) {
		dev_warn(ddev, "too many ports requested: %d\n", num_ports);
		num_ports = MAX_NUM_PORTS;
	}

	serial->num_ports = num_ports;
	serial->num_bulk_in = num_bulk_in;
	serial->num_bulk_out = num_bulk_out;
	serial->num_interrupt_in = num_interrupt_in;
	serial->num_interrupt_out = num_interrupt_out;

	/* found all that we need */
	dev_info(ddev, "%s converter detected\n", type->description);

	/* create our ports, we need as many as the max endpoints */
	/* we don't use num_ports here because some devices have more
	   endpoint pairs than ports */
	max_endpoints = max(num_bulk_in, num_bulk_out);
	max_endpoints = max(max_endpoints, num_interrupt_in);
	max_endpoints = max(max_endpoints, num_interrupt_out);
	max_endpoints = max(max_endpoints, (int)serial->num_ports);
	serial->num_port_pointers = max_endpoints;

	dev_dbg(ddev, "setting up %d port structure(s)\n", max_endpoints);
	for (i = 0; i < max_endpoints; ++i) {
		port = kzalloc(sizeof(struct usb_serial_port), GFP_KERNEL);
		if (!port)
			goto probe_error;
		tty_port_init(&port->port);
		port->port.ops = &serial_port_ops;
		port->serial = serial;
		spin_lock_init(&port->lock);
		/* Keep this for private driver use for the moment but
		   should probably go away */
		INIT_WORK(&port->work, usb_serial_port_work);
		serial->port[i] = port;
		port->dev.parent = &interface->dev;
		port->dev.driver = NULL;
		port->dev.bus = &usb_serial_bus_type;
		port->dev.release = &usb_serial_port_release;
		port->dev.groups = usb_serial_port_groups;
		device_initialize(&port->dev);
	}

	/* set up the endpoint information */
	for (i = 0; i < num_bulk_in; ++i) {
		endpoint = bulk_in_endpoint[i];
		port = serial->port[i];
		buffer_size = max_t(int, serial->type->bulk_in_size,
				usb_endpoint_maxp(endpoint));
		port->bulk_in_size = buffer_size;
		port->bulk_in_endpointAddress = endpoint->bEndpointAddress;

		for (j = 0; j < ARRAY_SIZE(port->read_urbs); ++j) {
			set_bit(j, &port->read_urbs_free);
			port->read_urbs[j] = usb_alloc_urb(0, GFP_KERNEL);
			if (!port->read_urbs[j])
				goto probe_error;
			port->bulk_in_buffers[j] = kmalloc(buffer_size,
								GFP_KERNEL);
			if (!port->bulk_in_buffers[j])
				goto probe_error;
			usb_fill_bulk_urb(port->read_urbs[j], dev,
					usb_rcvbulkpipe(dev,
						endpoint->bEndpointAddress),
					port->bulk_in_buffers[j], buffer_size,
					serial->type->read_bulk_callback,
					port);
		}

		port->read_urb = port->read_urbs[0];
		port->bulk_in_buffer = port->bulk_in_buffers[0];
	}

	for (i = 0; i < num_bulk_out; ++i) {
		endpoint = bulk_out_endpoint[i];
		port = serial->port[i];
		if (kfifo_alloc(&port->write_fifo, PAGE_SIZE, GFP_KERNEL))
			goto probe_error;
		buffer_size = serial->type->bulk_out_size;
		if (!buffer_size)
			buffer_size = usb_endpoint_maxp(endpoint);
		port->bulk_out_size = buffer_size;
		port->bulk_out_endpointAddress = endpoint->bEndpointAddress;

		for (j = 0; j < ARRAY_SIZE(port->write_urbs); ++j) {
			set_bit(j, &port->write_urbs_free);
			port->write_urbs[j] = usb_alloc_urb(0, GFP_KERNEL);
			if (!port->write_urbs[j])
				goto probe_error;
			port->bulk_out_buffers[j] = kmalloc(buffer_size,
								GFP_KERNEL);
			if (!port->bulk_out_buffers[j])
				goto probe_error;
			usb_fill_bulk_urb(port->write_urbs[j], dev,
					usb_sndbulkpipe(dev,
						endpoint->bEndpointAddress),
					port->bulk_out_buffers[j], buffer_size,
					serial->type->write_bulk_callback,
					port);
		}

		port->write_urb = port->write_urbs[0];
		port->bulk_out_buffer = port->bulk_out_buffers[0];
	}

	if (serial->type->read_int_callback) {
		for (i = 0; i < num_interrupt_in; ++i) {
			endpoint = interrupt_in_endpoint[i];
			port = serial->port[i];
			port->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
			if (!port->interrupt_in_urb)
				goto probe_error;
			buffer_size = usb_endpoint_maxp(endpoint);
			port->interrupt_in_endpointAddress =
						endpoint->bEndpointAddress;
			port->interrupt_in_buffer = kmalloc(buffer_size,
								GFP_KERNEL);
			if (!port->interrupt_in_buffer)
				goto probe_error;
			usb_fill_int_urb(port->interrupt_in_urb, dev,
				usb_rcvintpipe(dev,
						endpoint->bEndpointAddress),
				port->interrupt_in_buffer, buffer_size,
				serial->type->read_int_callback, port,
				endpoint->bInterval);
		}
	} else if (num_interrupt_in) {
		dev_dbg(ddev, "The device claims to support interrupt in transfers, but read_int_callback is not defined\n");
	}

	if (serial->type->write_int_callback) {
		for (i = 0; i < num_interrupt_out; ++i) {
			endpoint = interrupt_out_endpoint[i];
			port = serial->port[i];
			port->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
			if (!port->interrupt_out_urb)
				goto probe_error;
			buffer_size = usb_endpoint_maxp(endpoint);
			port->interrupt_out_size = buffer_size;
			port->interrupt_out_endpointAddress =
						endpoint->bEndpointAddress;
			port->interrupt_out_buffer = kmalloc(buffer_size,
								GFP_KERNEL);
			if (!port->interrupt_out_buffer)
				goto probe_error;
			usb_fill_int_urb(port->interrupt_out_urb, dev,
				usb_sndintpipe(dev,
						  endpoint->bEndpointAddress),
				port->interrupt_out_buffer, buffer_size,
				serial->type->write_int_callback, port,
				endpoint->bInterval);
		}
	} else if (num_interrupt_out) {
		dev_dbg(ddev, "The device claims to support interrupt out transfers, but write_int_callback is not defined\n");
	}

	usb_set_intfdata(interface, serial);

	/* if this device type has an attach function, call it */
	if (type->attach) {
		retval = type->attach(serial);
		if (retval < 0)
			goto probe_error;
		serial->attached = 1;
		if (retval > 0) {
			/* quietly accept this device, but don't bind to a
			   serial port as it's about to disappear */
			serial->num_ports = 0;
			goto exit;
		}
	} else {
		serial->attached = 1;
	}

	/* Avoid race with tty_open and serial_install by setting the
	 * disconnected flag and not clearing it until all ports have been
	 * registered.
	 */
	serial->disconnected = 1;

	if (allocate_minors(serial, num_ports)) {
		dev_err(ddev, "No more free serial minor numbers\n");
		goto probe_error;
	}

	/* register all of the individual ports with the driver core */
	for (i = 0; i < num_ports; ++i) {
		port = serial->port[i];
		dev_set_name(&port->dev, "ttyUSB%d", port->minor);
		dev_dbg(ddev, "registering %s\n", dev_name(&port->dev));
		device_enable_async_suspend(&port->dev);

		retval = device_add(&port->dev);
		if (retval)
			dev_err(ddev, "Error registering port device, continuing\n");
	}

	serial->disconnected = 0;

	if (num_ports > 0)
		usb_serial_console_init(serial->port[0]->minor);
exit:
	module_put(type->driver.owner);
	return 0;

probe_error:
	usb_serial_put(serial);
	module_put(type->driver.owner);
	return -EIO;
}

static void usb_serial_disconnect(struct usb_interface *interface)
{
	int i;
	struct usb_serial *serial = usb_get_intfdata(interface);
	struct device *dev = &interface->dev;
	struct usb_serial_port *port;
	struct tty_struct *tty;

	usb_serial_console_disconnect(serial);

	mutex_lock(&serial->disc_mutex);
	/* must set a flag, to signal subdrivers */
	serial->disconnected = 1;
	mutex_unlock(&serial->disc_mutex);

	for (i = 0; i < serial->num_ports; ++i) {
		port = serial->port[i];
		tty = tty_port_tty_get(&port->port);
		if (tty) {
			tty_vhangup(tty);
			tty_kref_put(tty);
		}
		usb_serial_port_poison_urbs(port);
		wake_up_interruptible(&port->port.delta_msr_wait);
		cancel_work_sync(&port->work);
		if (device_is_registered(&port->dev))
			device_del(&port->dev);
	}
	if (serial->type->disconnect)
		serial->type->disconnect(serial);

	/* let the last holder of this object cause it to be cleaned up */
	usb_serial_put(serial);
	dev_info(dev, "device disconnected\n");
}

int usb_serial_suspend(struct usb_interface *intf, pm_message_t message)
{
	struct usb_serial *serial = usb_get_intfdata(intf);
	int i, r = 0;

	serial->suspending = 1;

	/*
	 * serial->type->suspend() MUST return 0 in system sleep context,
	 * otherwise, the resume callback has to recover device from
	 * previous suspend failure.
	 */
	if (serial->type->suspend) {
		r = serial->type->suspend(serial, message);
		if (r < 0) {
			serial->suspending = 0;
			goto err_out;
		}
	}

	for (i = 0; i < serial->num_ports; ++i)
		usb_serial_port_poison_urbs(serial->port[i]);
err_out:
	return r;
}
EXPORT_SYMBOL(usb_serial_suspend);

static void usb_serial_unpoison_port_urbs(struct usb_serial *serial)
{
	int i;

	for (i = 0; i < serial->num_ports; ++i)
		usb_serial_port_unpoison_urbs(serial->port[i]);
}

int usb_serial_resume(struct usb_interface *intf)
{
	struct usb_serial *serial = usb_get_intfdata(intf);
	int rv;

	usb_serial_unpoison_port_urbs(serial);

	serial->suspending = 0;
	if (serial->type->resume)
		rv = serial->type->resume(serial);
	else
		rv = usb_serial_generic_resume(serial);

	return rv;
}
EXPORT_SYMBOL(usb_serial_resume);

static int usb_serial_reset_resume(struct usb_interface *intf)
{
	struct usb_serial *serial = usb_get_intfdata(intf);
	int rv;

	usb_serial_unpoison_port_urbs(serial);

	serial->suspending = 0;
	if (serial->type->reset_resume) {
		rv = serial->type->reset_resume(serial);
	} else {
		rv = -EOPNOTSUPP;
		intf->needs_binding = 1;
	}

	return rv;
}

static const struct tty_operations serial_ops = {
	.open =			serial_open,
	.close =		serial_close,
	.write =		serial_write,
	.hangup =		serial_hangup,
	.write_room =		serial_write_room,
	.ioctl =		serial_ioctl,
	.set_termios =		serial_set_termios,
	.throttle =		serial_throttle,
	.unthrottle =		serial_unthrottle,
	.break_ctl =		serial_break,
	.chars_in_buffer =	serial_chars_in_buffer,
	.wait_until_sent =	serial_wait_until_sent,
	.tiocmget =		serial_tiocmget,
	.tiocmset =		serial_tiocmset,
	.get_icount =		serial_get_icount,
	.cleanup =		serial_cleanup,
	.install =		serial_install,
	.proc_fops =		&serial_proc_fops,
};


struct tty_driver *usb_serial_tty_driver;

/* Driver structure we register with the USB core */
static struct usb_driver usb_serial_driver = {
	.name =		"usbserial",
	.probe =	usb_serial_probe,
	.disconnect =	usb_serial_disconnect,
	.suspend =	usb_serial_suspend,
	.resume =	usb_serial_resume,
	.no_dynamic_id =	1,
	.supports_autosuspend =	1,
};

static int __init usb_serial_init(void)
{
	int result;

	usb_serial_tty_driver = alloc_tty_driver(USB_SERIAL_TTY_MINORS);
	if (!usb_serial_tty_driver)
		return -ENOMEM;

	/* Initialize our global data */
	result = bus_register(&usb_serial_bus_type);
	if (result) {
		pr_err("%s - registering bus driver failed\n", __func__);
		goto exit_bus;
	}

	usb_serial_tty_driver->driver_name = "usbserial";
	usb_serial_tty_driver->name = "ttyUSB";
	usb_serial_tty_driver->major = USB_SERIAL_TTY_MAJOR;
	usb_serial_tty_driver->minor_start = 0;
	usb_serial_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
	usb_serial_tty_driver->subtype = SERIAL_TYPE_NORMAL;
	usb_serial_tty_driver->flags = TTY_DRIVER_REAL_RAW |
						TTY_DRIVER_DYNAMIC_DEV;
	usb_serial_tty_driver->init_termios = tty_std_termios;
	usb_serial_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD
							| HUPCL | CLOCAL;
	usb_serial_tty_driver->init_termios.c_ispeed = 9600;
	usb_serial_tty_driver->init_termios.c_ospeed = 9600;
	tty_set_operations(usb_serial_tty_driver, &serial_ops);
	result = tty_register_driver(usb_serial_tty_driver);
	if (result) {
		pr_err("%s - tty_register_driver failed\n", __func__);
		goto exit_reg_driver;
	}

	/* register the USB driver */
	result = usb_register(&usb_serial_driver);
	if (result < 0) {
		pr_err("%s - usb_register failed\n", __func__);
		goto exit_tty;
	}

	/* register the generic driver, if we should */
	result = usb_serial_generic_register();
	if (result < 0) {
		pr_err("%s - registering generic driver failed\n", __func__);
		goto exit_generic;
	}

	return result;

exit_generic:
	usb_deregister(&usb_serial_driver);

exit_tty:
	tty_unregister_driver(usb_serial_tty_driver);

exit_reg_driver:
	bus_unregister(&usb_serial_bus_type);

exit_bus:
	pr_err("%s - returning with error %d\n", __func__, result);
	put_tty_driver(usb_serial_tty_driver);
	return result;
}


static void __exit usb_serial_exit(void)
{
	usb_serial_console_exit();

	usb_serial_generic_deregister();

	usb_deregister(&usb_serial_driver);
	tty_unregister_driver(usb_serial_tty_driver);
	put_tty_driver(usb_serial_tty_driver);
	bus_unregister(&usb_serial_bus_type);
	idr_destroy(&serial_minors);
}


module_init(usb_serial_init);
module_exit(usb_serial_exit);

#define set_to_generic_if_null(type, function)				\
	do {								\
		if (!type->function) {					\
			type->function = usb_serial_generic_##function;	\
			pr_debug("%s: using generic " #function	"\n",	\
						type->driver.name);	\
		}							\
	} while (0)

static void usb_serial_operations_init(struct usb_serial_driver *device)
{
	set_to_generic_if_null(device, open);
	set_to_generic_if_null(device, write);
	set_to_generic_if_null(device, close);
	set_to_generic_if_null(device, write_room);
	set_to_generic_if_null(device, chars_in_buffer);
	if (device->tx_empty)
		set_to_generic_if_null(device, wait_until_sent);
	set_to_generic_if_null(device, read_bulk_callback);
	set_to_generic_if_null(device, write_bulk_callback);
	set_to_generic_if_null(device, process_read_urb);
	set_to_generic_if_null(device, prepare_write_buffer);
}

static int usb_serial_register(struct usb_serial_driver *driver)
{
	int retval;

	if (usb_disabled())
		return -ENODEV;

	if (!driver->description)
		driver->description = driver->driver.name;
	if (!driver->usb_driver) {
		WARN(1, "Serial driver %s has no usb_driver\n",
				driver->description);
		return -EINVAL;
	}

	usb_serial_operations_init(driver);

	/* Add this device to our list of devices */
	mutex_lock(&table_lock);
	list_add(&driver->driver_list, &usb_serial_driver_list);

	retval = usb_serial_bus_register(driver);
	if (retval) {
		pr_err("problem %d when registering driver %s\n", retval, driver->description);
		list_del(&driver->driver_list);
	} else {
		pr_info("USB Serial support registered for %s\n", driver->description);
	}
	mutex_unlock(&table_lock);
	return retval;
}

static void usb_serial_deregister(struct usb_serial_driver *device)
{
	pr_info("USB Serial deregistering driver %s\n", device->description);

	mutex_lock(&table_lock);
	list_del(&device->driver_list);
	mutex_unlock(&table_lock);

	usb_serial_bus_deregister(device);
}

/**
 * usb_serial_register_drivers - register drivers for a usb-serial module
 * @serial_drivers: NULL-terminated array of pointers to drivers to be registered
 * @name: name of the usb_driver for this set of @serial_drivers
 * @id_table: list of all devices this @serial_drivers set binds to
 *
 * Registers all the drivers in the @serial_drivers array, and dynamically
 * creates a struct usb_driver with the name @name and id_table of @id_table.
 */
int usb_serial_register_drivers(struct usb_serial_driver *const serial_drivers[],
				const char *name,
				const struct usb_device_id *id_table)
{
	int rc;
	struct usb_driver *udriver;
	struct usb_serial_driver * const *sd;

	/*
	 * udriver must be registered before any of the serial drivers,
	 * because the store_new_id() routine for the serial drivers (in
	 * bus.c) probes udriver.
	 *
	 * Performance hack: We don't want udriver to be probed until
	 * the serial drivers are registered, because the probe would
	 * simply fail for lack of a matching serial driver.
	 * So we leave udriver's id_table set to NULL until we are all set.
	 *
	 * Suspend/resume support is implemented in the usb-serial core,
	 * so fill in the PM-related fields in udriver.
	 */
	udriver = kzalloc(sizeof(*udriver), GFP_KERNEL);
	if (!udriver)
		return -ENOMEM;

	udriver->name = name;
	udriver->no_dynamic_id = 1;
	udriver->supports_autosuspend = 1;
	udriver->suspend = usb_serial_suspend;
	udriver->resume = usb_serial_resume;
	udriver->probe = usb_serial_probe;
	udriver->disconnect = usb_serial_disconnect;

	/* we only set the reset_resume field if the serial_driver has one */
	for (sd = serial_drivers; *sd; ++sd) {
		if ((*sd)->reset_resume) {
			udriver->reset_resume = usb_serial_reset_resume;
			break;
		}
	}

	rc = usb_register(udriver);
	if (rc)
		goto failed_usb_register;

	for (sd = serial_drivers; *sd; ++sd) {
		(*sd)->usb_driver = udriver;
		rc = usb_serial_register(*sd);
		if (rc)
			goto failed;
	}

	/* Now set udriver's id_table and look for matches */
	udriver->id_table = id_table;
	rc = driver_attach(&udriver->drvwrap.driver);
	return 0;

 failed:
	while (sd-- > serial_drivers)
		usb_serial_deregister(*sd);
	usb_deregister(udriver);
failed_usb_register:
	kfree(udriver);
	return rc;
}
EXPORT_SYMBOL_GPL(usb_serial_register_drivers);

/**
 * usb_serial_deregister_drivers - deregister drivers for a usb-serial module
 * @serial_drivers: NULL-terminated array of pointers to drivers to be deregistered
 *
 * Deregisters all the drivers in the @serial_drivers array and deregisters and
 * frees the struct usb_driver that was created by the call to
 * usb_serial_register_drivers().
 */
void usb_serial_deregister_drivers(struct usb_serial_driver *const serial_drivers[])
{
	struct usb_driver *udriver = (*serial_drivers)->usb_driver;

	for (; *serial_drivers; ++serial_drivers)
		usb_serial_deregister(*serial_drivers);
	usb_deregister(udriver);
	kfree(udriver);
}
EXPORT_SYMBOL_GPL(usb_serial_deregister_drivers);

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