Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
   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
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
/*
 * cdc-acm.c
 *
 * Copyright (c) 1999 Armin Fuerst	<fuerst@in.tum.de>
 * Copyright (c) 1999 Pavel Machek	<pavel@ucw.cz>
 * Copyright (c) 1999 Johannes Erdfelt	<johannes@erdfelt.com>
 * Copyright (c) 2000 Vojtech Pavlik	<vojtech@suse.cz>
 * Copyright (c) 2004 Oliver Neukum	<oliver@neukum.name>
 * Copyright (c) 2005 David Kubicek	<dave@awk.cz>
 * Copyright (c) 2011 Johan Hovold	<jhovold@gmail.com>
 *
 * USB Abstract Control Model driver for USB modems and ISDN adapters
 *
 * Sponsored by SuSE
 *
 * 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 02111-1307 USA
 */

#undef DEBUG
#undef VERBOSE_DEBUG

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/serial.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/cdc.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
#include <linux/list.h>

#include "cdc-acm.h"


#define DRIVER_AUTHOR "Armin Fuerst, Pavel Machek, Johannes Erdfelt, Vojtech Pavlik, David Kubicek, Johan Hovold"
#define DRIVER_DESC "USB Abstract Control Model driver for USB modems and ISDN adapters"

static struct usb_driver acm_driver;
static struct tty_driver *acm_tty_driver;
static struct acm *acm_table[ACM_TTY_MINORS];

static DEFINE_MUTEX(acm_table_lock);

/*
 * acm_table accessors
 */

/*
 * Look up an ACM structure by index. If found and not disconnected, increment
 * its refcount and return it with its mutex held.
 */
static struct acm *acm_get_by_index(unsigned index)
{
	struct acm *acm;

	mutex_lock(&acm_table_lock);
	acm = acm_table[index];
	if (acm) {
		mutex_lock(&acm->mutex);
		if (acm->disconnected) {
			mutex_unlock(&acm->mutex);
			acm = NULL;
		} else {
			tty_port_get(&acm->port);
			mutex_unlock(&acm->mutex);
		}
	}
	mutex_unlock(&acm_table_lock);
	return acm;
}

/*
 * Try to find an available minor number and if found, associate it with 'acm'.
 */
static int acm_alloc_minor(struct acm *acm)
{
	int minor;

	mutex_lock(&acm_table_lock);
	for (minor = 0; minor < ACM_TTY_MINORS; minor++) {
		if (!acm_table[minor]) {
			acm_table[minor] = acm;
			break;
		}
	}
	mutex_unlock(&acm_table_lock);

	return minor;
}

/* Release the minor number associated with 'acm'.  */
static void acm_release_minor(struct acm *acm)
{
	mutex_lock(&acm_table_lock);
	acm_table[acm->minor] = NULL;
	mutex_unlock(&acm_table_lock);
}

/*
 * Functions for ACM control messages.
 */

static int acm_ctrl_msg(struct acm *acm, int request, int value,
							void *buf, int len)
{
	int retval = usb_control_msg(acm->dev, usb_sndctrlpipe(acm->dev, 0),
		request, USB_RT_ACM, value,
		acm->control->altsetting[0].desc.bInterfaceNumber,
		buf, len, 5000);
	dev_dbg(&acm->control->dev,
			"%s - rq 0x%02x, val %#x, len %#x, result %d\n",
			__func__, request, value, len, retval);
	return retval < 0 ? retval : 0;
}

/* devices aren't required to support these requests.
 * the cdc acm descriptor tells whether they do...
 */
#define acm_set_control(acm, control) \
	acm_ctrl_msg(acm, USB_CDC_REQ_SET_CONTROL_LINE_STATE, control, NULL, 0)
#define acm_set_line(acm, line) \
	acm_ctrl_msg(acm, USB_CDC_REQ_SET_LINE_CODING, 0, line, sizeof *(line))
#define acm_send_break(acm, ms) \
	acm_ctrl_msg(acm, USB_CDC_REQ_SEND_BREAK, ms, NULL, 0)

/*
 * Write buffer management.
 * All of these assume proper locks taken by the caller.
 */

static int acm_wb_alloc(struct acm *acm)
{
	int i, wbn;
	struct acm_wb *wb;

	wbn = 0;
	i = 0;
	for (;;) {
		wb = &acm->wb[wbn];
		if (!wb->use) {
			wb->use = 1;
			return wbn;
		}
		wbn = (wbn + 1) % ACM_NW;
		if (++i >= ACM_NW)
			return -1;
	}
}

static int acm_wb_is_avail(struct acm *acm)
{
	int i, n;
	unsigned long flags;

	n = ACM_NW;
	spin_lock_irqsave(&acm->write_lock, flags);
	for (i = 0; i < ACM_NW; i++)
		n -= acm->wb[i].use;
	spin_unlock_irqrestore(&acm->write_lock, flags);
	return n;
}

/*
 * Finish write. Caller must hold acm->write_lock
 */
static void acm_write_done(struct acm *acm, struct acm_wb *wb)
{
	wb->use = 0;
	acm->transmitting--;
	usb_autopm_put_interface_async(acm->control);
}

/*
 * Poke write.
 *
 * the caller is responsible for locking
 */

static int acm_start_wb(struct acm *acm, struct acm_wb *wb)
{
	int rc;

	acm->transmitting++;

	wb->urb->transfer_buffer = wb->buf;
	wb->urb->transfer_dma = wb->dmah;
	wb->urb->transfer_buffer_length = wb->len;
	wb->urb->dev = acm->dev;

	rc = usb_submit_urb(wb->urb, GFP_ATOMIC);
	if (rc < 0) {
		dev_err(&acm->data->dev,
			"%s - usb_submit_urb(write bulk) failed: %d\n",
			__func__, rc);
		acm_write_done(acm, wb);
	}
	return rc;
}

static int acm_write_start(struct acm *acm, int wbn)
{
	unsigned long flags;
	struct acm_wb *wb = &acm->wb[wbn];
	int rc;

	spin_lock_irqsave(&acm->write_lock, flags);
	if (!acm->dev) {
		wb->use = 0;
		spin_unlock_irqrestore(&acm->write_lock, flags);
		return -ENODEV;
	}

	dev_vdbg(&acm->data->dev, "%s - susp_count %d\n", __func__,
							acm->susp_count);
	usb_autopm_get_interface_async(acm->control);
	if (acm->susp_count) {
		if (!acm->delayed_wb)
			acm->delayed_wb = wb;
		else
			usb_autopm_put_interface_async(acm->control);
		spin_unlock_irqrestore(&acm->write_lock, flags);
		return 0;	/* A white lie */
	}
	usb_mark_last_busy(acm->dev);

	rc = acm_start_wb(acm, wb);
	spin_unlock_irqrestore(&acm->write_lock, flags);

	return rc;

}
/*
 * attributes exported through sysfs
 */
static ssize_t show_caps
(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct acm *acm = usb_get_intfdata(intf);

	return sprintf(buf, "%d", acm->ctrl_caps);
}
static DEVICE_ATTR(bmCapabilities, S_IRUGO, show_caps, NULL);

static ssize_t show_country_codes
(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct acm *acm = usb_get_intfdata(intf);

	memcpy(buf, acm->country_codes, acm->country_code_size);
	return acm->country_code_size;
}

static DEVICE_ATTR(wCountryCodes, S_IRUGO, show_country_codes, NULL);

static ssize_t show_country_rel_date
(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct acm *acm = usb_get_intfdata(intf);

	return sprintf(buf, "%d", acm->country_rel_date);
}

static DEVICE_ATTR(iCountryCodeRelDate, S_IRUGO, show_country_rel_date, NULL);
/*
 * Interrupt handlers for various ACM device responses
 */

/* control interface reports status changes with "interrupt" transfers */
static void acm_ctrl_irq(struct urb *urb)
{
	struct acm *acm = urb->context;
	struct usb_cdc_notification *dr = urb->transfer_buffer;
	struct tty_struct *tty;
	unsigned char *data;
	int newctrl;
	int retval;
	int status = urb->status;

	switch (status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dev_dbg(&acm->control->dev,
				"%s - urb shutting down with status: %d\n",
				__func__, status);
		return;
	default:
		dev_dbg(&acm->control->dev,
				"%s - nonzero urb status received: %d\n",
				__func__, status);
		goto exit;
	}

	usb_mark_last_busy(acm->dev);

	data = (unsigned char *)(dr + 1);
	switch (dr->bNotificationType) {
	case USB_CDC_NOTIFY_NETWORK_CONNECTION:
		dev_dbg(&acm->control->dev, "%s - network connection: %d\n",
							__func__, dr->wValue);
		break;

	case USB_CDC_NOTIFY_SERIAL_STATE:
		tty = tty_port_tty_get(&acm->port);
		newctrl = get_unaligned_le16(data);

		if (tty) {
			if (!acm->clocal &&
				(acm->ctrlin & ~newctrl & ACM_CTRL_DCD)) {
				dev_dbg(&acm->control->dev,
					"%s - calling hangup\n", __func__);
				tty_hangup(tty);
			}
			tty_kref_put(tty);
		}

		acm->ctrlin = newctrl;

		dev_dbg(&acm->control->dev,
			"%s - input control lines: dcd%c dsr%c break%c "
			"ring%c framing%c parity%c overrun%c\n",
			__func__,
			acm->ctrlin & ACM_CTRL_DCD ? '+' : '-',
			acm->ctrlin & ACM_CTRL_DSR ? '+' : '-',
			acm->ctrlin & ACM_CTRL_BRK ? '+' : '-',
			acm->ctrlin & ACM_CTRL_RI  ? '+' : '-',
			acm->ctrlin & ACM_CTRL_FRAMING ? '+' : '-',
			acm->ctrlin & ACM_CTRL_PARITY ? '+' : '-',
			acm->ctrlin & ACM_CTRL_OVERRUN ? '+' : '-');
			break;

	default:
		dev_dbg(&acm->control->dev,
			"%s - unknown notification %d received: index %d "
			"len %d data0 %d data1 %d\n",
			__func__,
			dr->bNotificationType, dr->wIndex,
			dr->wLength, data[0], data[1]);
		break;
	}
exit:
	retval = usb_submit_urb(urb, GFP_ATOMIC);
	if (retval)
		dev_err(&acm->control->dev, "%s - usb_submit_urb failed: %d\n",
							__func__, retval);
}

static int acm_submit_read_urb(struct acm *acm, int index, gfp_t mem_flags)
{
	int res;

	if (!test_and_clear_bit(index, &acm->read_urbs_free))
		return 0;

	dev_vdbg(&acm->data->dev, "%s - urb %d\n", __func__, index);

	res = usb_submit_urb(acm->read_urbs[index], mem_flags);
	if (res) {
		if (res != -EPERM) {
			dev_err(&acm->data->dev,
					"%s - usb_submit_urb failed: %d\n",
					__func__, res);
		}
		set_bit(index, &acm->read_urbs_free);
		return res;
	}

	return 0;
}

static int acm_submit_read_urbs(struct acm *acm, gfp_t mem_flags)
{
	int res;
	int i;

	for (i = 0; i < acm->rx_buflimit; ++i) {
		res = acm_submit_read_urb(acm, i, mem_flags);
		if (res)
			return res;
	}

	return 0;
}

static void acm_process_read_urb(struct acm *acm, struct urb *urb)
{
	struct tty_struct *tty;

	if (!urb->actual_length)
		return;

	tty = tty_port_tty_get(&acm->port);
	if (!tty)
		return;

	tty_insert_flip_string(tty, urb->transfer_buffer, urb->actual_length);
	tty_flip_buffer_push(tty);

	tty_kref_put(tty);
}

static void acm_read_bulk_callback(struct urb *urb)
{
	struct acm_rb *rb = urb->context;
	struct acm *acm = rb->instance;
	unsigned long flags;

	dev_vdbg(&acm->data->dev, "%s - urb %d, len %d\n", __func__,
					rb->index, urb->actual_length);
	set_bit(rb->index, &acm->read_urbs_free);

	if (!acm->dev) {
		dev_dbg(&acm->data->dev, "%s - disconnected\n", __func__);
		return;
	}
	usb_mark_last_busy(acm->dev);

	if (urb->status) {
		dev_dbg(&acm->data->dev, "%s - non-zero urb status: %d\n",
							__func__, urb->status);
		return;
	}
	acm_process_read_urb(acm, urb);

	/* throttle device if requested by tty */
	spin_lock_irqsave(&acm->read_lock, flags);
	acm->throttled = acm->throttle_req;
	if (!acm->throttled && !acm->susp_count) {
		spin_unlock_irqrestore(&acm->read_lock, flags);
		acm_submit_read_urb(acm, rb->index, GFP_ATOMIC);
	} else {
		spin_unlock_irqrestore(&acm->read_lock, flags);
	}
}

/* data interface wrote those outgoing bytes */
static void acm_write_bulk(struct urb *urb)
{
	struct acm_wb *wb = urb->context;
	struct acm *acm = wb->instance;
	unsigned long flags;

	if (urb->status	|| (urb->actual_length != urb->transfer_buffer_length))
		dev_vdbg(&acm->data->dev, "%s - len %d/%d, status %d\n",
			__func__,
			urb->actual_length,
			urb->transfer_buffer_length,
			urb->status);

	spin_lock_irqsave(&acm->write_lock, flags);
	acm_write_done(acm, wb);
	spin_unlock_irqrestore(&acm->write_lock, flags);
	schedule_work(&acm->work);
}

static void acm_softint(struct work_struct *work)
{
	struct acm *acm = container_of(work, struct acm, work);
	struct tty_struct *tty;

	dev_vdbg(&acm->data->dev, "%s\n", __func__);

	tty = tty_port_tty_get(&acm->port);
	if (!tty)
		return;
	tty_wakeup(tty);
	tty_kref_put(tty);
}

/*
 * TTY handlers
 */

static int acm_tty_install(struct tty_driver *driver, struct tty_struct *tty)
{
	struct acm *acm;
	int retval;

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

	acm = acm_get_by_index(tty->index);
	if (!acm)
		return -ENODEV;

	retval = tty_init_termios(tty);
	if (retval)
		goto error_init_termios;

	tty->driver_data = acm;

	/* Final install (we use the default method) */
	tty_driver_kref_get(driver);
	tty->count++;
	driver->ttys[tty->index] = tty;

	return 0;

error_init_termios:
	tty_port_put(&acm->port);
	return retval;
}

static int acm_tty_open(struct tty_struct *tty, struct file *filp)
{
	struct acm *acm = tty->driver_data;

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

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

static int acm_port_activate(struct tty_port *port, struct tty_struct *tty)
{
	struct acm *acm = container_of(port, struct acm, port);
	int retval = -ENODEV;

	dev_dbg(&acm->control->dev, "%s\n", __func__);

	mutex_lock(&acm->mutex);
	if (acm->disconnected)
		goto disconnected;

	retval = usb_autopm_get_interface(acm->control);
	if (retval)
		goto error_get_interface;

	/*
	 * FIXME: Why do we need this? Allocating 64K of physically contiguous
	 * memory is really nasty...
	 */
	set_bit(TTY_NO_WRITE_SPLIT, &tty->flags);
	acm->control->needs_remote_wakeup = 1;

	acm->ctrlurb->dev = acm->dev;
	if (usb_submit_urb(acm->ctrlurb, GFP_KERNEL)) {
		dev_err(&acm->control->dev,
			"%s - usb_submit_urb(ctrl irq) failed\n", __func__);
		goto error_submit_urb;
	}

	acm->ctrlout = ACM_CTRL_DTR | ACM_CTRL_RTS;
	if (acm_set_control(acm, acm->ctrlout) < 0 &&
	    (acm->ctrl_caps & USB_CDC_CAP_LINE))
		goto error_set_control;

	usb_autopm_put_interface(acm->control);

	if (acm_submit_read_urbs(acm, GFP_KERNEL))
		goto error_submit_read_urbs;

	mutex_unlock(&acm->mutex);

	return 0;

error_submit_read_urbs:
	acm->ctrlout = 0;
	acm_set_control(acm, acm->ctrlout);
error_set_control:
	usb_kill_urb(acm->ctrlurb);
error_submit_urb:
	usb_autopm_put_interface(acm->control);
error_get_interface:
disconnected:
	mutex_unlock(&acm->mutex);
	return retval;
}

static void acm_port_destruct(struct tty_port *port)
{
	struct acm *acm = container_of(port, struct acm, port);

	dev_dbg(&acm->control->dev, "%s\n", __func__);

	tty_unregister_device(acm_tty_driver, acm->minor);
	acm_release_minor(acm);
	usb_put_intf(acm->control);
	kfree(acm->country_codes);
	kfree(acm);
}

static void acm_port_shutdown(struct tty_port *port)
{
	struct acm *acm = container_of(port, struct acm, port);
	int i;

	dev_dbg(&acm->control->dev, "%s\n", __func__);

	mutex_lock(&acm->mutex);
	if (!acm->disconnected) {
		usb_autopm_get_interface(acm->control);
		acm_set_control(acm, acm->ctrlout = 0);
		usb_kill_urb(acm->ctrlurb);
		for (i = 0; i < ACM_NW; i++)
			usb_kill_urb(acm->wb[i].urb);
		for (i = 0; i < acm->rx_buflimit; i++)
			usb_kill_urb(acm->read_urbs[i]);
		acm->control->needs_remote_wakeup = 0;
		usb_autopm_put_interface(acm->control);
	}
	mutex_unlock(&acm->mutex);
}

static void acm_tty_cleanup(struct tty_struct *tty)
{
	struct acm *acm = tty->driver_data;
	dev_dbg(&acm->control->dev, "%s\n", __func__);
	tty_port_put(&acm->port);
}

static void acm_tty_hangup(struct tty_struct *tty)
{
	struct acm *acm = tty->driver_data;
	dev_dbg(&acm->control->dev, "%s\n", __func__);
	tty_port_hangup(&acm->port);
}

static void acm_tty_close(struct tty_struct *tty, struct file *filp)
{
	struct acm *acm = tty->driver_data;
	dev_dbg(&acm->control->dev, "%s\n", __func__);
	tty_port_close(&acm->port, tty, filp);
}

static int acm_tty_write(struct tty_struct *tty,
					const unsigned char *buf, int count)
{
	struct acm *acm = tty->driver_data;
	int stat;
	unsigned long flags;
	int wbn;
	struct acm_wb *wb;

	if (!count)
		return 0;

	dev_vdbg(&acm->data->dev, "%s - count %d\n", __func__, count);

	spin_lock_irqsave(&acm->write_lock, flags);
	wbn = acm_wb_alloc(acm);
	if (wbn < 0) {
		spin_unlock_irqrestore(&acm->write_lock, flags);
		return 0;
	}
	wb = &acm->wb[wbn];

	count = (count > acm->writesize) ? acm->writesize : count;
	dev_vdbg(&acm->data->dev, "%s - write %d\n", __func__, count);
	memcpy(wb->buf, buf, count);
	wb->len = count;
	spin_unlock_irqrestore(&acm->write_lock, flags);

	stat = acm_write_start(acm, wbn);
	if (stat < 0)
		return stat;
	return count;
}

static int acm_tty_write_room(struct tty_struct *tty)
{
	struct acm *acm = tty->driver_data;
	/*
	 * Do not let the line discipline to know that we have a reserve,
	 * or it might get too enthusiastic.
	 */
	return acm_wb_is_avail(acm) ? acm->writesize : 0;
}

static int acm_tty_chars_in_buffer(struct tty_struct *tty)
{
	struct acm *acm = tty->driver_data;
	/*
	 * if the device was unplugged then any remaining characters fell out
	 * of the connector ;)
	 */
	if (acm->disconnected)
		return 0;
	/*
	 * This is inaccurate (overcounts), but it works.
	 */
	return (ACM_NW - acm_wb_is_avail(acm)) * acm->writesize;
}

static void acm_tty_throttle(struct tty_struct *tty)
{
	struct acm *acm = tty->driver_data;

	spin_lock_irq(&acm->read_lock);
	acm->throttle_req = 1;
	spin_unlock_irq(&acm->read_lock);
}

static void acm_tty_unthrottle(struct tty_struct *tty)
{
	struct acm *acm = tty->driver_data;
	unsigned int was_throttled;

	spin_lock_irq(&acm->read_lock);
	was_throttled = acm->throttled;
	acm->throttled = 0;
	acm->throttle_req = 0;
	spin_unlock_irq(&acm->read_lock);

	if (was_throttled)
		acm_submit_read_urbs(acm, GFP_KERNEL);
}

static int acm_tty_break_ctl(struct tty_struct *tty, int state)
{
	struct acm *acm = tty->driver_data;
	int retval;

	retval = acm_send_break(acm, state ? 0xffff : 0);
	if (retval < 0)
		dev_dbg(&acm->control->dev, "%s - send break failed\n",
								__func__);
	return retval;
}

static int acm_tty_tiocmget(struct tty_struct *tty)
{
	struct acm *acm = tty->driver_data;

	return (acm->ctrlout & ACM_CTRL_DTR ? TIOCM_DTR : 0) |
	       (acm->ctrlout & ACM_CTRL_RTS ? TIOCM_RTS : 0) |
	       (acm->ctrlin  & ACM_CTRL_DSR ? TIOCM_DSR : 0) |
	       (acm->ctrlin  & ACM_CTRL_RI  ? TIOCM_RI  : 0) |
	       (acm->ctrlin  & ACM_CTRL_DCD ? TIOCM_CD  : 0) |
	       TIOCM_CTS;
}

static int acm_tty_tiocmset(struct tty_struct *tty,
			    unsigned int set, unsigned int clear)
{
	struct acm *acm = tty->driver_data;
	unsigned int newctrl;

	newctrl = acm->ctrlout;
	set = (set & TIOCM_DTR ? ACM_CTRL_DTR : 0) |
					(set & TIOCM_RTS ? ACM_CTRL_RTS : 0);
	clear = (clear & TIOCM_DTR ? ACM_CTRL_DTR : 0) |
					(clear & TIOCM_RTS ? ACM_CTRL_RTS : 0);

	newctrl = (newctrl & ~clear) | set;

	if (acm->ctrlout == newctrl)
		return 0;
	return acm_set_control(acm, acm->ctrlout = newctrl);
}

static int acm_tty_ioctl(struct tty_struct *tty,
					unsigned int cmd, unsigned long arg)
{
	return -ENOIOCTLCMD;
}

static const __u32 acm_tty_speed[] = {
	0, 50, 75, 110, 134, 150, 200, 300, 600,
	1200, 1800, 2400, 4800, 9600, 19200, 38400,
	57600, 115200, 230400, 460800, 500000, 576000,
	921600, 1000000, 1152000, 1500000, 2000000,
	2500000, 3000000, 3500000, 4000000
};

static const __u8 acm_tty_size[] = {
	5, 6, 7, 8
};

static void acm_tty_set_termios(struct tty_struct *tty,
						struct ktermios *termios_old)
{
	struct acm *acm = tty->driver_data;
	struct ktermios *termios = tty->termios;
	struct usb_cdc_line_coding newline;
	int newctrl = acm->ctrlout;

	newline.dwDTERate = cpu_to_le32(tty_get_baud_rate(tty));
	newline.bCharFormat = termios->c_cflag & CSTOPB ? 2 : 0;
	newline.bParityType = termios->c_cflag & PARENB ?
				(termios->c_cflag & PARODD ? 1 : 2) +
				(termios->c_cflag & CMSPAR ? 2 : 0) : 0;
	newline.bDataBits = acm_tty_size[(termios->c_cflag & CSIZE) >> 4];
	/* FIXME: Needs to clear unsupported bits in the termios */
	acm->clocal = ((termios->c_cflag & CLOCAL) != 0);

	if (!newline.dwDTERate) {
		newline.dwDTERate = acm->line.dwDTERate;
		newctrl &= ~ACM_CTRL_DTR;
	} else
		newctrl |=  ACM_CTRL_DTR;

	if (newctrl != acm->ctrlout)
		acm_set_control(acm, acm->ctrlout = newctrl);

	if (memcmp(&acm->line, &newline, sizeof newline)) {
		memcpy(&acm->line, &newline, sizeof newline);
		dev_dbg(&acm->control->dev, "%s - set line: %d %d %d %d\n",
			__func__,
			le32_to_cpu(newline.dwDTERate),
			newline.bCharFormat, newline.bParityType,
			newline.bDataBits);
		acm_set_line(acm, &acm->line);
	}
}

static const struct tty_port_operations acm_port_ops = {
	.shutdown = acm_port_shutdown,
	.activate = acm_port_activate,
	.destruct = acm_port_destruct,
};

/*
 * USB probe and disconnect routines.
 */

/* Little helpers: write/read buffers free */
static void acm_write_buffers_free(struct acm *acm)
{
	int i;
	struct acm_wb *wb;
	struct usb_device *usb_dev = interface_to_usbdev(acm->control);

	for (wb = &acm->wb[0], i = 0; i < ACM_NW; i++, wb++)
		usb_free_coherent(usb_dev, acm->writesize, wb->buf, wb->dmah);
}

static void acm_read_buffers_free(struct acm *acm)
{
	struct usb_device *usb_dev = interface_to_usbdev(acm->control);
	int i;

	for (i = 0; i < acm->rx_buflimit; i++)
		usb_free_coherent(usb_dev, acm->readsize,
			  acm->read_buffers[i].base, acm->read_buffers[i].dma);
}

/* Little helper: write buffers allocate */
static int acm_write_buffers_alloc(struct acm *acm)
{
	int i;
	struct acm_wb *wb;

	for (wb = &acm->wb[0], i = 0; i < ACM_NW; i++, wb++) {
		wb->buf = usb_alloc_coherent(acm->dev, acm->writesize, GFP_KERNEL,
		    &wb->dmah);
		if (!wb->buf) {
			while (i != 0) {
				--i;
				--wb;
				usb_free_coherent(acm->dev, acm->writesize,
				    wb->buf, wb->dmah);
			}
			return -ENOMEM;
		}
	}
	return 0;
}

static int acm_probe(struct usb_interface *intf,
		     const struct usb_device_id *id)
{
	struct usb_cdc_union_desc *union_header = NULL;
	struct usb_cdc_country_functional_desc *cfd = NULL;
	unsigned char *buffer = intf->altsetting->extra;
	int buflen = intf->altsetting->extralen;
	struct usb_interface *control_interface;
	struct usb_interface *data_interface;
	struct usb_endpoint_descriptor *epctrl = NULL;
	struct usb_endpoint_descriptor *epread = NULL;
	struct usb_endpoint_descriptor *epwrite = NULL;
	struct usb_device *usb_dev = interface_to_usbdev(intf);
	struct acm *acm;
	int minor;
	int ctrlsize, readsize;
	u8 *buf;
	u8 ac_management_function = 0;
	u8 call_management_function = 0;
	int call_interface_num = -1;
	int data_interface_num = -1;
	unsigned long quirks;
	int num_rx_buf;
	int i;
	int combined_interfaces = 0;

	/* normal quirks */
	quirks = (unsigned long)id->driver_info;
	num_rx_buf = (quirks == SINGLE_RX_URB) ? 1 : ACM_NR;

	/* handle quirks deadly to normal probing*/
	if (quirks == NO_UNION_NORMAL) {
		data_interface = usb_ifnum_to_if(usb_dev, 1);
		control_interface = usb_ifnum_to_if(usb_dev, 0);
		goto skip_normal_probe;
	}

	/* normal probing*/
	if (!buffer) {
		dev_err(&intf->dev, "Weird descriptor references\n");
		return -EINVAL;
	}

	if (!buflen) {
		if (intf->cur_altsetting->endpoint &&
				intf->cur_altsetting->endpoint->extralen &&
				intf->cur_altsetting->endpoint->extra) {
			dev_dbg(&intf->dev,
				"Seeking extra descriptors on endpoint\n");
			buflen = intf->cur_altsetting->endpoint->extralen;
			buffer = intf->cur_altsetting->endpoint->extra;
		} else {
			dev_err(&intf->dev,
				"Zero length descriptor references\n");
			return -EINVAL;
		}
	}

	while (buflen > 0) {
		if (buffer[1] != USB_DT_CS_INTERFACE) {
			dev_err(&intf->dev, "skipping garbage\n");
			goto next_desc;
		}

		switch (buffer[2]) {
		case USB_CDC_UNION_TYPE: /* we've found it */
			if (union_header) {
				dev_err(&intf->dev, "More than one "
					"union descriptor, skipping ...\n");
				goto next_desc;
			}
			union_header = (struct usb_cdc_union_desc *)buffer;
			break;
		case USB_CDC_COUNTRY_TYPE: /* export through sysfs*/
			cfd = (struct usb_cdc_country_functional_desc *)buffer;
			break;
		case USB_CDC_HEADER_TYPE: /* maybe check version */
			break; /* for now we ignore it */
		case USB_CDC_ACM_TYPE:
			ac_management_function = buffer[3];
			break;
		case USB_CDC_CALL_MANAGEMENT_TYPE:
			call_management_function = buffer[3];
			call_interface_num = buffer[4];
			if ( (quirks & NOT_A_MODEM) == 0 && (call_management_function & 3) != 3)
				dev_err(&intf->dev, "This device cannot do calls on its own. It is not a modem.\n");
			break;
		default:
			/* there are LOTS more CDC descriptors that
			 * could legitimately be found here.
			 */
			dev_dbg(&intf->dev, "Ignoring descriptor: "
					"type %02x, length %d\n",
					buffer[2], buffer[0]);
			break;
		}
next_desc:
		buflen -= buffer[0];
		buffer += buffer[0];
	}

	if (!union_header) {
		if (call_interface_num > 0) {
			dev_dbg(&intf->dev, "No union descriptor, using call management descriptor\n");
			/* quirks for Droids MuIn LCD */
			if (quirks & NO_DATA_INTERFACE)
				data_interface = usb_ifnum_to_if(usb_dev, 0);
			else
				data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = call_interface_num));
			control_interface = intf;
		} else {
			if (intf->cur_altsetting->desc.bNumEndpoints != 3) {
				dev_dbg(&intf->dev,"No union descriptor, giving up\n");
				return -ENODEV;
			} else {
				dev_warn(&intf->dev,"No union descriptor, testing for castrated device\n");
				combined_interfaces = 1;
				control_interface = data_interface = intf;
				goto look_for_collapsed_interface;
			}
		}
	} else {
		control_interface = usb_ifnum_to_if(usb_dev, union_header->bMasterInterface0);
		data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = union_header->bSlaveInterface0));
		if (!control_interface || !data_interface) {
			dev_dbg(&intf->dev, "no interfaces\n");
			return -ENODEV;
		}
	}

	if (data_interface_num != call_interface_num)
		dev_dbg(&intf->dev, "Separate call control interface. That is not fully supported.\n");

	if (control_interface == data_interface) {
		/* some broken devices designed for windows work this way */
		dev_warn(&intf->dev,"Control and data interfaces are not separated!\n");
		combined_interfaces = 1;
		/* a popular other OS doesn't use it */
		quirks |= NO_CAP_LINE;
		if (data_interface->cur_altsetting->desc.bNumEndpoints != 3) {
			dev_err(&intf->dev, "This needs exactly 3 endpoints\n");
			return -EINVAL;
		}
look_for_collapsed_interface:
		for (i = 0; i < 3; i++) {
			struct usb_endpoint_descriptor *ep;
			ep = &data_interface->cur_altsetting->endpoint[i].desc;

			if (usb_endpoint_is_int_in(ep))
				epctrl = ep;
			else if (usb_endpoint_is_bulk_out(ep))
				epwrite = ep;
			else if (usb_endpoint_is_bulk_in(ep))
				epread = ep;
			else
				return -EINVAL;
		}
		if (!epctrl || !epread || !epwrite)
			return -ENODEV;
		else
			goto made_compressed_probe;
	}

skip_normal_probe:

	/*workaround for switched interfaces */
	if (data_interface->cur_altsetting->desc.bInterfaceClass
						!= CDC_DATA_INTERFACE_TYPE) {
		if (control_interface->cur_altsetting->desc.bInterfaceClass
						== CDC_DATA_INTERFACE_TYPE) {
			struct usb_interface *t;
			dev_dbg(&intf->dev,
				"Your device has switched interfaces.\n");
			t = control_interface;
			control_interface = data_interface;
			data_interface = t;
		} else {
			return -EINVAL;
		}
	}

	/* Accept probe requests only for the control interface */
	if (!combined_interfaces && intf != control_interface)
		return -ENODEV;

	if (!combined_interfaces && usb_interface_claimed(data_interface)) {
		/* valid in this context */
		dev_dbg(&intf->dev, "The data interface isn't available\n");
		return -EBUSY;
	}


	if (data_interface->cur_altsetting->desc.bNumEndpoints < 2)
		return -EINVAL;

	epctrl = &control_interface->cur_altsetting->endpoint[0].desc;
	epread = &data_interface->cur_altsetting->endpoint[0].desc;
	epwrite = &data_interface->cur_altsetting->endpoint[1].desc;


	/* workaround for switched endpoints */
	if (!usb_endpoint_dir_in(epread)) {
		/* descriptors are swapped */
		struct usb_endpoint_descriptor *t;
		dev_dbg(&intf->dev,
			"The data interface has switched endpoints\n");
		t = epread;
		epread = epwrite;
		epwrite = t;
	}
made_compressed_probe:
	dev_dbg(&intf->dev, "interfaces are valid\n");

	acm = kzalloc(sizeof(struct acm), GFP_KERNEL);
	if (acm == NULL) {
		dev_err(&intf->dev, "out of memory (acm kzalloc)\n");
		goto alloc_fail;
	}

	minor = acm_alloc_minor(acm);
	if (minor == ACM_TTY_MINORS) {
		dev_err(&intf->dev, "no more free acm devices\n");
		kfree(acm);
		return -ENODEV;
	}

	ctrlsize = usb_endpoint_maxp(epctrl);
	readsize = usb_endpoint_maxp(epread) *
				(quirks == SINGLE_RX_URB ? 1 : 2);
	acm->combined_interfaces = combined_interfaces;
	acm->writesize = usb_endpoint_maxp(epwrite) * 20;
	acm->control = control_interface;
	acm->data = data_interface;
	acm->minor = minor;
	acm->dev = usb_dev;
	acm->ctrl_caps = ac_management_function;
	if (quirks & NO_CAP_LINE)
		acm->ctrl_caps &= ~USB_CDC_CAP_LINE;
	acm->ctrlsize = ctrlsize;
	acm->readsize = readsize;
	acm->rx_buflimit = num_rx_buf;
	INIT_WORK(&acm->work, acm_softint);
	spin_lock_init(&acm->write_lock);
	spin_lock_init(&acm->read_lock);
	mutex_init(&acm->mutex);
	acm->rx_endpoint = usb_rcvbulkpipe(usb_dev, epread->bEndpointAddress);
	acm->is_int_ep = usb_endpoint_xfer_int(epread);
	if (acm->is_int_ep)
		acm->bInterval = epread->bInterval;
	tty_port_init(&acm->port);
	acm->port.ops = &acm_port_ops;

	buf = usb_alloc_coherent(usb_dev, ctrlsize, GFP_KERNEL, &acm->ctrl_dma);
	if (!buf) {
		dev_err(&intf->dev, "out of memory (ctrl buffer alloc)\n");
		goto alloc_fail2;
	}
	acm->ctrl_buffer = buf;

	if (acm_write_buffers_alloc(acm) < 0) {
		dev_err(&intf->dev, "out of memory (write buffer alloc)\n");
		goto alloc_fail4;
	}

	acm->ctrlurb = usb_alloc_urb(0, GFP_KERNEL);
	if (!acm->ctrlurb) {
		dev_err(&intf->dev, "out of memory (ctrlurb kmalloc)\n");
		goto alloc_fail5;
	}
	for (i = 0; i < num_rx_buf; i++) {
		struct acm_rb *rb = &(acm->read_buffers[i]);
		struct urb *urb;

		rb->base = usb_alloc_coherent(acm->dev, readsize, GFP_KERNEL,
								&rb->dma);
		if (!rb->base) {
			dev_err(&intf->dev, "out of memory "
					"(read bufs usb_alloc_coherent)\n");
			goto alloc_fail6;
		}
		rb->index = i;
		rb->instance = acm;

		urb = usb_alloc_urb(0, GFP_KERNEL);
		if (!urb) {
			dev_err(&intf->dev,
				"out of memory (read urbs usb_alloc_urb)\n");
			goto alloc_fail6;
		}
		urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
		urb->transfer_dma = rb->dma;
		if (acm->is_int_ep) {
			usb_fill_int_urb(urb, acm->dev,
					 acm->rx_endpoint,
					 rb->base,
					 acm->readsize,
					 acm_read_bulk_callback, rb,
					 acm->bInterval);
		} else {
			usb_fill_bulk_urb(urb, acm->dev,
					  acm->rx_endpoint,
					  rb->base,
					  acm->readsize,
					  acm_read_bulk_callback, rb);
		}

		acm->read_urbs[i] = urb;
		__set_bit(i, &acm->read_urbs_free);
	}
	for (i = 0; i < ACM_NW; i++) {
		struct acm_wb *snd = &(acm->wb[i]);

		snd->urb = usb_alloc_urb(0, GFP_KERNEL);
		if (snd->urb == NULL) {
			dev_err(&intf->dev,
				"out of memory (write urbs usb_alloc_urb)\n");
			goto alloc_fail7;
		}

		if (usb_endpoint_xfer_int(epwrite))
			usb_fill_int_urb(snd->urb, usb_dev,
				usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),
				NULL, acm->writesize, acm_write_bulk, snd, epwrite->bInterval);
		else
			usb_fill_bulk_urb(snd->urb, usb_dev,
				usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),
				NULL, acm->writesize, acm_write_bulk, snd);
		snd->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
		snd->instance = acm;
	}

	usb_set_intfdata(intf, acm);

	i = device_create_file(&intf->dev, &dev_attr_bmCapabilities);
	if (i < 0)
		goto alloc_fail7;

	if (cfd) { /* export the country data */
		acm->country_codes = kmalloc(cfd->bLength - 4, GFP_KERNEL);
		if (!acm->country_codes)
			goto skip_countries;
		acm->country_code_size = cfd->bLength - 4;
		memcpy(acm->country_codes, (u8 *)&cfd->wCountyCode0,
							cfd->bLength - 4);
		acm->country_rel_date = cfd->iCountryCodeRelDate;

		i = device_create_file(&intf->dev, &dev_attr_wCountryCodes);
		if (i < 0) {
			kfree(acm->country_codes);
			acm->country_codes = NULL;
			acm->country_code_size = 0;
			goto skip_countries;
		}

		i = device_create_file(&intf->dev,
						&dev_attr_iCountryCodeRelDate);
		if (i < 0) {
			device_remove_file(&intf->dev, &dev_attr_wCountryCodes);
			kfree(acm->country_codes);
			acm->country_codes = NULL;
			acm->country_code_size = 0;
			goto skip_countries;
		}
	}

skip_countries:
	usb_fill_int_urb(acm->ctrlurb, usb_dev,
			 usb_rcvintpipe(usb_dev, epctrl->bEndpointAddress),
			 acm->ctrl_buffer, ctrlsize, acm_ctrl_irq, acm,
			 /* works around buggy devices */
			 epctrl->bInterval ? epctrl->bInterval : 0xff);
	acm->ctrlurb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
	acm->ctrlurb->transfer_dma = acm->ctrl_dma;

	dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);

	acm_set_control(acm, acm->ctrlout);

	acm->line.dwDTERate = cpu_to_le32(9600);
	acm->line.bDataBits = 8;
	acm_set_line(acm, &acm->line);

	usb_driver_claim_interface(&acm_driver, data_interface, acm);
	usb_set_intfdata(data_interface, acm);

	usb_get_intf(control_interface);
	tty_register_device(acm_tty_driver, minor, &control_interface->dev);

	return 0;
alloc_fail7:
	for (i = 0; i < ACM_NW; i++)
		usb_free_urb(acm->wb[i].urb);
alloc_fail6:
	for (i = 0; i < num_rx_buf; i++)
		usb_free_urb(acm->read_urbs[i]);
	acm_read_buffers_free(acm);
	usb_free_urb(acm->ctrlurb);
alloc_fail5:
	acm_write_buffers_free(acm);
alloc_fail4:
	usb_free_coherent(usb_dev, ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
alloc_fail2:
	acm_release_minor(acm);
	kfree(acm);
alloc_fail:
	return -ENOMEM;
}

static void stop_data_traffic(struct acm *acm)
{
	int i;

	dev_dbg(&acm->control->dev, "%s\n", __func__);

	usb_kill_urb(acm->ctrlurb);
	for (i = 0; i < ACM_NW; i++)
		usb_kill_urb(acm->wb[i].urb);
	for (i = 0; i < acm->rx_buflimit; i++)
		usb_kill_urb(acm->read_urbs[i]);

	cancel_work_sync(&acm->work);
}

static void acm_disconnect(struct usb_interface *intf)
{
	struct acm *acm = usb_get_intfdata(intf);
	struct usb_device *usb_dev = interface_to_usbdev(intf);
	struct tty_struct *tty;
	int i;

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

	/* sibling interface is already cleaning up */
	if (!acm)
		return;

	mutex_lock(&acm->mutex);
	acm->disconnected = true;
	if (acm->country_codes) {
		device_remove_file(&acm->control->dev,
				&dev_attr_wCountryCodes);
		device_remove_file(&acm->control->dev,
				&dev_attr_iCountryCodeRelDate);
	}
	device_remove_file(&acm->control->dev, &dev_attr_bmCapabilities);
	usb_set_intfdata(acm->control, NULL);
	usb_set_intfdata(acm->data, NULL);
	mutex_unlock(&acm->mutex);

	tty = tty_port_tty_get(&acm->port);
	if (tty) {
		tty_vhangup(tty);
		tty_kref_put(tty);
	}

	stop_data_traffic(acm);

	usb_free_urb(acm->ctrlurb);
	for (i = 0; i < ACM_NW; i++)
		usb_free_urb(acm->wb[i].urb);
	for (i = 0; i < acm->rx_buflimit; i++)
		usb_free_urb(acm->read_urbs[i]);
	acm_write_buffers_free(acm);
	usb_free_coherent(usb_dev, acm->ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
	acm_read_buffers_free(acm);

	if (!acm->combined_interfaces)
		usb_driver_release_interface(&acm_driver, intf == acm->control ?
					acm->data : acm->control);

	tty_port_put(&acm->port);
}

#ifdef CONFIG_PM
static int acm_suspend(struct usb_interface *intf, pm_message_t message)
{
	struct acm *acm = usb_get_intfdata(intf);
	int cnt;

	if (PMSG_IS_AUTO(message)) {
		int b;

		spin_lock_irq(&acm->write_lock);
		b = acm->transmitting;
		spin_unlock_irq(&acm->write_lock);
		if (b)
			return -EBUSY;
	}

	spin_lock_irq(&acm->read_lock);
	spin_lock(&acm->write_lock);
	cnt = acm->susp_count++;
	spin_unlock(&acm->write_lock);
	spin_unlock_irq(&acm->read_lock);

	if (cnt)
		return 0;

	if (test_bit(ASYNCB_INITIALIZED, &acm->port.flags))
		stop_data_traffic(acm);

	return 0;
}

static int acm_resume(struct usb_interface *intf)
{
	struct acm *acm = usb_get_intfdata(intf);
	struct acm_wb *wb;
	int rv = 0;
	int cnt;

	spin_lock_irq(&acm->read_lock);
	acm->susp_count -= 1;
	cnt = acm->susp_count;
	spin_unlock_irq(&acm->read_lock);

	if (cnt)
		return 0;

	if (test_bit(ASYNCB_INITIALIZED, &acm->port.flags)) {
		rv = usb_submit_urb(acm->ctrlurb, GFP_NOIO);

		spin_lock_irq(&acm->write_lock);
		if (acm->delayed_wb) {
			wb = acm->delayed_wb;
			acm->delayed_wb = NULL;
			spin_unlock_irq(&acm->write_lock);
			acm_start_wb(acm, wb);
		} else {
			spin_unlock_irq(&acm->write_lock);
		}

		/*
		 * delayed error checking because we must
		 * do the write path at all cost
		 */
		if (rv < 0)
			goto err_out;

		rv = acm_submit_read_urbs(acm, GFP_NOIO);
	}

err_out:
	return rv;
}

static int acm_reset_resume(struct usb_interface *intf)
{
	struct acm *acm = usb_get_intfdata(intf);
	struct tty_struct *tty;

	if (test_bit(ASYNCB_INITIALIZED, &acm->port.flags)) {
		tty = tty_port_tty_get(&acm->port);
		if (tty) {
			tty_hangup(tty);
			tty_kref_put(tty);
		}
	}

	return acm_resume(intf);
}

#endif /* CONFIG_PM */

#define NOKIA_PCSUITE_ACM_INFO(x) \
		USB_DEVICE_AND_INTERFACE_INFO(0x0421, x, \
		USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM, \
		USB_CDC_ACM_PROTO_VENDOR)

#define SAMSUNG_PCSUITE_ACM_INFO(x) \
		USB_DEVICE_AND_INTERFACE_INFO(0x04e7, x, \
		USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM, \
		USB_CDC_ACM_PROTO_VENDOR)

/*
 * USB driver structure.
 */

static const struct usb_device_id acm_ids[] = {
	/* quirky and broken devices */
	{ USB_DEVICE(0x0870, 0x0001), /* Metricom GS Modem */
	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
	},
	{ USB_DEVICE(0x0e8d, 0x0003), /* FIREFLY, MediaTek Inc; andrey.arapov@gmail.com */
	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
	},
	{ USB_DEVICE(0x0e8d, 0x3329), /* MediaTek Inc GPS */
	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
	},
	{ USB_DEVICE(0x0482, 0x0203), /* KYOCERA AH-K3001V */
	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
	},
	{ USB_DEVICE(0x079b, 0x000f), /* BT On-Air USB MODEM */
	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
	},
	{ USB_DEVICE(0x0ace, 0x1602), /* ZyDAS 56K USB MODEM */
	.driver_info = SINGLE_RX_URB,
	},
	{ USB_DEVICE(0x0ace, 0x1608), /* ZyDAS 56K USB MODEM */
	.driver_info = SINGLE_RX_URB, /* firmware bug */
	},
	{ USB_DEVICE(0x0ace, 0x1611), /* ZyDAS 56K USB MODEM - new version */
	.driver_info = SINGLE_RX_URB, /* firmware bug */
	},
	{ USB_DEVICE(0x22b8, 0x7000), /* Motorola Q Phone */
	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
	},
	{ USB_DEVICE(0x0803, 0x3095), /* Zoom Telephonics Model 3095F USB MODEM */
	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
	},
	{ USB_DEVICE(0x0572, 0x1321), /* Conexant USB MODEM CX93010 */
	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
	},
	{ USB_DEVICE(0x0572, 0x1324), /* Conexant USB MODEM RD02-D400 */
	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
	},
	{ USB_DEVICE(0x0572, 0x1328), /* Shiro / Aztech USB MODEM UM-3100 */
	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
	},
	{ USB_DEVICE(0x22b8, 0x6425), /* Motorola MOTOMAGX phones */
	},
	/* Motorola H24 HSPA module: */
	{ USB_DEVICE(0x22b8, 0x2d91) }, /* modem                                */
	{ USB_DEVICE(0x22b8, 0x2d92) }, /* modem           + diagnostics        */
	{ USB_DEVICE(0x22b8, 0x2d93) }, /* modem + AT port                      */
	{ USB_DEVICE(0x22b8, 0x2d95) }, /* modem + AT port + diagnostics        */
	{ USB_DEVICE(0x22b8, 0x2d96) }, /* modem                         + NMEA */
	{ USB_DEVICE(0x22b8, 0x2d97) }, /* modem           + diagnostics + NMEA */
	{ USB_DEVICE(0x22b8, 0x2d99) }, /* modem + AT port               + NMEA */
	{ USB_DEVICE(0x22b8, 0x2d9a) }, /* modem + AT port + diagnostics + NMEA */

	{ USB_DEVICE(0x0572, 0x1329), /* Hummingbird huc56s (Conexant) */
	.driver_info = NO_UNION_NORMAL, /* union descriptor misplaced on
					   data interface instead of
					   communications interface.
					   Maybe we should define a new
					   quirk for this. */
	},
	{ USB_DEVICE(0x1bbb, 0x0003), /* Alcatel OT-I650 */
	.driver_info = NO_UNION_NORMAL, /* reports zero length descriptor */
	},
	{ USB_DEVICE(0x1576, 0x03b1), /* Maretron USB100 */
	.driver_info = NO_UNION_NORMAL, /* reports zero length descriptor */
	},

	/* Nokia S60 phones expose two ACM channels. The first is
	 * a modem and is picked up by the standard AT-command
	 * information below. The second is 'vendor-specific' but
	 * is treated as a serial device at the S60 end, so we want
	 * to expose it on Linux too. */
	{ NOKIA_PCSUITE_ACM_INFO(0x042D), }, /* Nokia 3250 */
	{ NOKIA_PCSUITE_ACM_INFO(0x04D8), }, /* Nokia 5500 Sport */
	{ NOKIA_PCSUITE_ACM_INFO(0x04C9), }, /* Nokia E50 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0419), }, /* Nokia E60 */
	{ NOKIA_PCSUITE_ACM_INFO(0x044D), }, /* Nokia E61 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0001), }, /* Nokia E61i */
	{ NOKIA_PCSUITE_ACM_INFO(0x0475), }, /* Nokia E62 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0508), }, /* Nokia E65 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0418), }, /* Nokia E70 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0425), }, /* Nokia N71 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0486), }, /* Nokia N73 */
	{ NOKIA_PCSUITE_ACM_INFO(0x04DF), }, /* Nokia N75 */
	{ NOKIA_PCSUITE_ACM_INFO(0x000e), }, /* Nokia N77 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0445), }, /* Nokia N80 */
	{ NOKIA_PCSUITE_ACM_INFO(0x042F), }, /* Nokia N91 & N91 8GB */
	{ NOKIA_PCSUITE_ACM_INFO(0x048E), }, /* Nokia N92 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0420), }, /* Nokia N93 */
	{ NOKIA_PCSUITE_ACM_INFO(0x04E6), }, /* Nokia N93i  */
	{ NOKIA_PCSUITE_ACM_INFO(0x04B2), }, /* Nokia 5700 XpressMusic */
	{ NOKIA_PCSUITE_ACM_INFO(0x0134), }, /* Nokia 6110 Navigator (China) */
	{ NOKIA_PCSUITE_ACM_INFO(0x046E), }, /* Nokia 6110 Navigator */
	{ NOKIA_PCSUITE_ACM_INFO(0x002f), }, /* Nokia 6120 classic &  */
	{ NOKIA_PCSUITE_ACM_INFO(0x0088), }, /* Nokia 6121 classic */
	{ NOKIA_PCSUITE_ACM_INFO(0x00fc), }, /* Nokia 6124 classic */
	{ NOKIA_PCSUITE_ACM_INFO(0x0042), }, /* Nokia E51 */
	{ NOKIA_PCSUITE_ACM_INFO(0x00b0), }, /* Nokia E66 */
	{ NOKIA_PCSUITE_ACM_INFO(0x00ab), }, /* Nokia E71 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0481), }, /* Nokia N76 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0007), }, /* Nokia N81 & N81 8GB */
	{ NOKIA_PCSUITE_ACM_INFO(0x0071), }, /* Nokia N82 */
	{ NOKIA_PCSUITE_ACM_INFO(0x04F0), }, /* Nokia N95 & N95-3 NAM */
	{ NOKIA_PCSUITE_ACM_INFO(0x0070), }, /* Nokia N95 8GB  */
	{ NOKIA_PCSUITE_ACM_INFO(0x00e9), }, /* Nokia 5320 XpressMusic */
	{ NOKIA_PCSUITE_ACM_INFO(0x0099), }, /* Nokia 6210 Navigator, RM-367 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0128), }, /* Nokia 6210 Navigator, RM-419 */
	{ NOKIA_PCSUITE_ACM_INFO(0x008f), }, /* Nokia 6220 Classic */
	{ NOKIA_PCSUITE_ACM_INFO(0x00a0), }, /* Nokia 6650 */
	{ NOKIA_PCSUITE_ACM_INFO(0x007b), }, /* Nokia N78 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0094), }, /* Nokia N85 */
	{ NOKIA_PCSUITE_ACM_INFO(0x003a), }, /* Nokia N96 & N96-3  */
	{ NOKIA_PCSUITE_ACM_INFO(0x00e9), }, /* Nokia 5320 XpressMusic */
	{ NOKIA_PCSUITE_ACM_INFO(0x0108), }, /* Nokia 5320 XpressMusic 2G */
	{ NOKIA_PCSUITE_ACM_INFO(0x01f5), }, /* Nokia N97, RM-505 */
	{ NOKIA_PCSUITE_ACM_INFO(0x02e3), }, /* Nokia 5230, RM-588 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0178), }, /* Nokia E63 */
	{ NOKIA_PCSUITE_ACM_INFO(0x010e), }, /* Nokia E75 */
	{ NOKIA_PCSUITE_ACM_INFO(0x02d9), }, /* Nokia 6760 Slide */
	{ NOKIA_PCSUITE_ACM_INFO(0x01d0), }, /* Nokia E52 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0223), }, /* Nokia E72 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0275), }, /* Nokia X6 */
	{ NOKIA_PCSUITE_ACM_INFO(0x026c), }, /* Nokia N97 Mini */
	{ NOKIA_PCSUITE_ACM_INFO(0x0154), }, /* Nokia 5800 XpressMusic */
	{ NOKIA_PCSUITE_ACM_INFO(0x04ce), }, /* Nokia E90 */
	{ NOKIA_PCSUITE_ACM_INFO(0x01d4), }, /* Nokia E55 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0302), }, /* Nokia N8 */
	{ NOKIA_PCSUITE_ACM_INFO(0x0335), }, /* Nokia E7 */
	{ NOKIA_PCSUITE_ACM_INFO(0x03cd), }, /* Nokia C7 */
	{ SAMSUNG_PCSUITE_ACM_INFO(0x6651), }, /* Samsung GTi8510 (INNOV8) */

	/* Support for Owen devices */
	{ USB_DEVICE(0x03eb, 0x0030), }, /* Owen SI30 */

	/* NOTE: non-Nokia COMM/ACM/0xff is likely MSFT RNDIS... NOT a modem! */

	/* Support Lego NXT using pbLua firmware */
	{ USB_DEVICE(0x0694, 0xff00),
	.driver_info = NOT_A_MODEM,
	},

	/* Support for Droids MuIn LCD */
	{ USB_DEVICE(0x04d8, 0x000b),
	.driver_info = NO_DATA_INTERFACE,
	},

	/* control interfaces without any protocol set */
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
		USB_CDC_PROTO_NONE) },

	/* control interfaces with various AT-command sets */
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
		USB_CDC_ACM_PROTO_AT_V25TER) },
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
		USB_CDC_ACM_PROTO_AT_PCCA101) },
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
		USB_CDC_ACM_PROTO_AT_PCCA101_WAKE) },
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
		USB_CDC_ACM_PROTO_AT_GSM) },
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
		USB_CDC_ACM_PROTO_AT_3G) },
	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
		USB_CDC_ACM_PROTO_AT_CDMA) },

	{ }
};

MODULE_DEVICE_TABLE(usb, acm_ids);

static struct usb_driver acm_driver = {
	.name =		"cdc_acm",
	.probe =	acm_probe,
	.disconnect =	acm_disconnect,
#ifdef CONFIG_PM
	.suspend =	acm_suspend,
	.resume =	acm_resume,
	.reset_resume =	acm_reset_resume,
#endif
	.id_table =	acm_ids,
#ifdef CONFIG_PM
	.supports_autosuspend = 1,
#endif
};

/*
 * TTY driver structures.
 */

static const struct tty_operations acm_ops = {
	.install =		acm_tty_install,
	.open =			acm_tty_open,
	.close =		acm_tty_close,
	.cleanup =		acm_tty_cleanup,
	.hangup =		acm_tty_hangup,
	.write =		acm_tty_write,
	.write_room =		acm_tty_write_room,
	.ioctl =		acm_tty_ioctl,
	.throttle =		acm_tty_throttle,
	.unthrottle =		acm_tty_unthrottle,
	.chars_in_buffer =	acm_tty_chars_in_buffer,
	.break_ctl =		acm_tty_break_ctl,
	.set_termios =		acm_tty_set_termios,
	.tiocmget =		acm_tty_tiocmget,
	.tiocmset =		acm_tty_tiocmset,
};

/*
 * Init / exit.
 */

static int __init acm_init(void)
{
	int retval;
	acm_tty_driver = alloc_tty_driver(ACM_TTY_MINORS);
	if (!acm_tty_driver)
		return -ENOMEM;
	acm_tty_driver->owner = THIS_MODULE,
	acm_tty_driver->driver_name = "acm",
	acm_tty_driver->name = "ttyACM",
	acm_tty_driver->major = ACM_TTY_MAJOR,
	acm_tty_driver->minor_start = 0,
	acm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL,
	acm_tty_driver->subtype = SERIAL_TYPE_NORMAL,
	acm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
	acm_tty_driver->init_termios = tty_std_termios;
	acm_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD |
								HUPCL | CLOCAL;
	tty_set_operations(acm_tty_driver, &acm_ops);

	retval = tty_register_driver(acm_tty_driver);
	if (retval) {
		put_tty_driver(acm_tty_driver);
		return retval;
	}

	retval = usb_register(&acm_driver);
	if (retval) {
		tty_unregister_driver(acm_tty_driver);
		put_tty_driver(acm_tty_driver);
		return retval;
	}

	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_DESC "\n");

	return 0;
}

static void __exit acm_exit(void)
{
	usb_deregister(&acm_driver);
	tty_unregister_driver(acm_tty_driver);
	put_tty_driver(acm_tty_driver);
}

module_init(acm_init);
module_exit(acm_exit);

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