summaryrefslogtreecommitdiffstats
path: root/drivers/net/usb/usbnet.c
blob: 3a6770a65d7836ace177cff2bb45c925b474a84a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
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
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
/*
 * USB Network driver infrastructure
 * Copyright (C) 2000-2005 by David Brownell
 * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

/*
 * This is a generic "USB networking" framework that works with several
 * kinds of full and high speed networking devices:  host-to-host cables,
 * smart usb peripherals, and actual Ethernet adapters.
 *
 * These devices usually differ in terms of control protocols (if they
 * even have one!) and sometimes they define new framing to wrap or batch
 * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
 * so interface (un)binding, endpoint I/O queues, fault handling, and other
 * issues can usefully be addressed by this framework.
 */

// #define	DEBUG			// error path messages, extra info
// #define	VERBOSE			// more; success messages

#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ctype.h>
#include <linux/ethtool.h>
#include <linux/workqueue.h>
#include <linux/mii.h>
#include <linux/usb.h>
#include <linux/usb/usbnet.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/pm_runtime.h>

#define DRIVER_VERSION		"22-Aug-2005"


/*-------------------------------------------------------------------------*/

/*
 * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
 * Several dozen bytes of IPv4 data can fit in two such transactions.
 * One maximum size Ethernet packet takes twenty four of them.
 * For high speed, each frame comfortably fits almost 36 max size
 * Ethernet packets (so queues should be bigger).
 *
 * The goal is to let the USB host controller be busy for 5msec or
 * more before an irq is required, under load.  Jumbograms change
 * the equation.
 */
#define	MAX_QUEUE_MEMORY	(60 * 1518)
#define	RX_QLEN(dev)		((dev)->rx_qlen)
#define	TX_QLEN(dev)		((dev)->tx_qlen)

// reawaken network queue this soon after stopping; else watchdog barks
#define TX_TIMEOUT_JIFFIES	(5*HZ)

/* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
 * us (it polls at HZ/4 usually) before we report too many false errors.
 */
#define THROTTLE_JIFFIES	(HZ/8)

// between wakeups
#define UNLINK_TIMEOUT_MS	3

/*-------------------------------------------------------------------------*/

// randomly generated ethernet address
static u8	node_id [ETH_ALEN];

static const char driver_name [] = "usbnet";

/* use ethtool to change the level for any given device */
static int msg_level = -1;
module_param (msg_level, int, 0);
MODULE_PARM_DESC (msg_level, "Override default message level");

/*-------------------------------------------------------------------------*/

/* handles CDC Ethernet and many other network "bulk data" interfaces */
int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
{
	int				tmp;
	struct usb_host_interface	*alt = NULL;
	struct usb_host_endpoint	*in = NULL, *out = NULL;
	struct usb_host_endpoint	*status = NULL;

	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
		unsigned	ep;

		in = out = status = NULL;
		alt = intf->altsetting + tmp;

		/* take the first altsetting with in-bulk + out-bulk;
		 * remember any status endpoint, just in case;
		 * ignore other endpoints and altsettings.
		 */
		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
			struct usb_host_endpoint	*e;
			int				intr = 0;

			e = alt->endpoint + ep;
			switch (e->desc.bmAttributes) {
			case USB_ENDPOINT_XFER_INT:
				if (!usb_endpoint_dir_in(&e->desc))
					continue;
				intr = 1;
				/* FALLTHROUGH */
			case USB_ENDPOINT_XFER_BULK:
				break;
			default:
				continue;
			}
			if (usb_endpoint_dir_in(&e->desc)) {
				if (!intr && !in)
					in = e;
				else if (intr && !status)
					status = e;
			} else {
				if (!out)
					out = e;
			}
		}
		if (in && out)
			break;
	}
	if (!alt || !in || !out)
		return -EINVAL;

	if (alt->desc.bAlternateSetting != 0 ||
	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
				alt->desc.bAlternateSetting);
		if (tmp < 0)
			return tmp;
	}

	dev->in = usb_rcvbulkpipe (dev->udev,
			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	dev->out = usb_sndbulkpipe (dev->udev,
			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	dev->status = status;
	return 0;
}
EXPORT_SYMBOL_GPL(usbnet_get_endpoints);

int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
{
	int 		tmp, i;
	unsigned char	buf [13];

	tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
	if (tmp != 12) {
		dev_dbg(&dev->udev->dev,
			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
		if (tmp >= 0)
			tmp = -EINVAL;
		return tmp;
	}
	for (i = tmp = 0; i < 6; i++, tmp += 2)
		dev->net->dev_addr [i] =
			(hex_to_bin(buf[tmp]) << 4) + hex_to_bin(buf[tmp + 1]);
	return 0;
}
EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);

static void intr_complete (struct urb *urb)
{
	struct usbnet	*dev = urb->context;
	int		status = urb->status;

	switch (status) {
	/* success */
	case 0:
		dev->driver_info->status(dev, urb);
		break;

	/* software-driven interface shutdown */
	case -ENOENT:		/* urb killed */
	case -ESHUTDOWN:	/* hardware gone */
		netif_dbg(dev, ifdown, dev->net,
			  "intr shutdown, code %d\n", status);
		return;

	/* NOTE:  not throttling like RX/TX, since this endpoint
	 * already polls infrequently
	 */
	default:
		netdev_dbg(dev->net, "intr status %d\n", status);
		break;
	}

	status = usb_submit_urb (urb, GFP_ATOMIC);
	if (status != 0)
		netif_err(dev, timer, dev->net,
			  "intr resubmit --> %d\n", status);
}

static int init_status (struct usbnet *dev, struct usb_interface *intf)
{
	char		*buf = NULL;
	unsigned	pipe = 0;
	unsigned	maxp;
	unsigned	period;

	if (!dev->driver_info->status)
		return 0;

	pipe = usb_rcvintpipe (dev->udev,
			dev->status->desc.bEndpointAddress
				& USB_ENDPOINT_NUMBER_MASK);
	maxp = usb_maxpacket (dev->udev, pipe, 0);

	/* avoid 1 msec chatter:  min 8 msec poll rate */
	period = max ((int) dev->status->desc.bInterval,
		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);

	buf = kmalloc (maxp, GFP_KERNEL);
	if (buf) {
		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
		if (!dev->interrupt) {
			kfree (buf);
			return -ENOMEM;
		} else {
			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
				buf, maxp, intr_complete, dev, period);
			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
			dev_dbg(&intf->dev,
				"status ep%din, %d bytes period %d\n",
				usb_pipeendpoint(pipe), maxp, period);
		}
	}
	return 0;
}

/* Submit the interrupt URB if not previously submitted, increasing refcount */
int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
{
	int ret = 0;

	WARN_ON_ONCE(dev->interrupt == NULL);
	if (dev->interrupt) {
		mutex_lock(&dev->interrupt_mutex);

		if (++dev->interrupt_count == 1)
			ret = usb_submit_urb(dev->interrupt, mem_flags);

		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
			dev->interrupt_count);
		mutex_unlock(&dev->interrupt_mutex);
	}
	return ret;
}
EXPORT_SYMBOL_GPL(usbnet_status_start);

/* For resume; submit interrupt URB if previously submitted */
static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
{
	int ret = 0;

	mutex_lock(&dev->interrupt_mutex);
	if (dev->interrupt_count) {
		ret = usb_submit_urb(dev->interrupt, mem_flags);
		dev_dbg(&dev->udev->dev,
			"submitted interrupt URB for resume\n");
	}
	mutex_unlock(&dev->interrupt_mutex);
	return ret;
}

/* Kill the interrupt URB if all submitters want it killed */
void usbnet_status_stop(struct usbnet *dev)
{
	if (dev->interrupt) {
		mutex_lock(&dev->interrupt_mutex);
		WARN_ON(dev->interrupt_count == 0);

		if (dev->interrupt_count && --dev->interrupt_count == 0)
			usb_kill_urb(dev->interrupt);

		dev_dbg(&dev->udev->dev,
			"decremented interrupt URB count to %d\n",
			dev->interrupt_count);
		mutex_unlock(&dev->interrupt_mutex);
	}
}
EXPORT_SYMBOL_GPL(usbnet_status_stop);

/* For suspend; always kill interrupt URB */
static void __usbnet_status_stop_force(struct usbnet *dev)
{
	if (dev->interrupt) {
		mutex_lock(&dev->interrupt_mutex);
		usb_kill_urb(dev->interrupt);
		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
		mutex_unlock(&dev->interrupt_mutex);
	}
}

/* Passes this packet up the stack, updating its accounting.
 * Some link protocols batch packets, so their rx_fixup paths
 * can return clones as well as just modify the original skb.
 */
void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
{
	int	status;

	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
		skb_queue_tail(&dev->rxq_pause, skb);
		return;
	}

	skb->protocol = eth_type_trans (skb, dev->net);
	dev->net->stats.rx_packets++;
	dev->net->stats.rx_bytes += skb->len;

	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
		  skb->len + sizeof (struct ethhdr), skb->protocol);
	memset (skb->cb, 0, sizeof (struct skb_data));

	if (skb_defer_rx_timestamp(skb))
		return;

	status = netif_rx (skb);
	if (status != NET_RX_SUCCESS)
		netif_dbg(dev, rx_err, dev->net,
			  "netif_rx status %d\n", status);
}
EXPORT_SYMBOL_GPL(usbnet_skb_return);

/* must be called if hard_mtu or rx_urb_size changed */
void usbnet_update_max_qlen(struct usbnet *dev)
{
	enum usb_device_speed speed = dev->udev->speed;

	switch (speed) {
	case USB_SPEED_HIGH:
		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
		break;
	case USB_SPEED_SUPER:
		/*
		 * Not take default 5ms qlen for super speed HC to
		 * save memory, and iperf tests show 2.5ms qlen can
		 * work well
		 */
		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
		break;
	default:
		dev->rx_qlen = dev->tx_qlen = 4;
	}
}
EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);


/*-------------------------------------------------------------------------
 *
 * Network Device Driver (peer link to "Host Device", from USB host)
 *
 *-------------------------------------------------------------------------*/

int usbnet_change_mtu (struct net_device *net, int new_mtu)
{
	struct usbnet	*dev = netdev_priv(net);
	int		ll_mtu = new_mtu + net->hard_header_len;
	int		old_hard_mtu = dev->hard_mtu;
	int		old_rx_urb_size = dev->rx_urb_size;

	if (new_mtu <= 0)
		return -EINVAL;
	// no second zero-length packet read wanted after mtu-sized packets
	if ((ll_mtu % dev->maxpacket) == 0)
		return -EDOM;
	net->mtu = new_mtu;

	dev->hard_mtu = net->mtu + net->hard_header_len;
	if (dev->rx_urb_size == old_hard_mtu) {
		dev->rx_urb_size = dev->hard_mtu;
		if (dev->rx_urb_size > old_rx_urb_size)
			usbnet_unlink_rx_urbs(dev);
	}

	/* max qlen depend on hard_mtu and rx_urb_size */
	usbnet_update_max_qlen(dev);

	return 0;
}
EXPORT_SYMBOL_GPL(usbnet_change_mtu);

/* The caller must hold list->lock */
static void __usbnet_queue_skb(struct sk_buff_head *list,
			struct sk_buff *newsk, enum skb_state state)
{
	struct skb_data *entry = (struct skb_data *) newsk->cb;

	__skb_queue_tail(list, newsk);
	entry->state = state;
}

/*-------------------------------------------------------------------------*/

/* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
 * completion callbacks.  2.5 should have fixed those bugs...
 */

static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
		struct sk_buff_head *list, enum skb_state state)
{
	unsigned long		flags;
	enum skb_state 		old_state;
	struct skb_data *entry = (struct skb_data *) skb->cb;

	spin_lock_irqsave(&list->lock, flags);
	old_state = entry->state;
	entry->state = state;
	__skb_unlink(skb, list);
	spin_unlock(&list->lock);
	spin_lock(&dev->done.lock);
	__skb_queue_tail(&dev->done, skb);
	if (dev->done.qlen == 1)
		tasklet_schedule(&dev->bh);
	spin_unlock_irqrestore(&dev->done.lock, flags);
	return old_state;
}

/* some work can't be done in tasklets, so we use keventd
 *
 * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
 * but tasklet_schedule() doesn't.  hope the failure is rare.
 */
void usbnet_defer_kevent (struct usbnet *dev, int work)
{
	set_bit (work, &dev->flags);
	if (!schedule_work (&dev->kevent)) {
		if (net_ratelimit())
			netdev_err(dev->net, "kevent %d may have been dropped\n", work);
	} else {
		netdev_dbg(dev->net, "kevent %d scheduled\n", work);
	}
}
EXPORT_SYMBOL_GPL(usbnet_defer_kevent);

/*-------------------------------------------------------------------------*/

static void rx_complete (struct urb *urb);

static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
{
	struct sk_buff		*skb;
	struct skb_data		*entry;
	int			retval = 0;
	unsigned long		lockflags;
	size_t			size = dev->rx_urb_size;

	/* prevent rx skb allocation when error ratio is high */
	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
		usb_free_urb(urb);
		return -ENOLINK;
	}

	skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
	if (!skb) {
		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
		usb_free_urb (urb);
		return -ENOMEM;
	}

	entry = (struct skb_data *) skb->cb;
	entry->urb = urb;
	entry->dev = dev;
	entry->length = 0;

	usb_fill_bulk_urb (urb, dev->udev, dev->in,
		skb->data, size, rx_complete, skb);

	spin_lock_irqsave (&dev->rxq.lock, lockflags);

	if (netif_running (dev->net) &&
	    netif_device_present (dev->net) &&
	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
		case -EPIPE:
			usbnet_defer_kevent (dev, EVENT_RX_HALT);
			break;
		case -ENOMEM:
			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
			break;
		case -ENODEV:
			netif_dbg(dev, ifdown, dev->net, "device gone\n");
			netif_device_detach (dev->net);
			break;
		case -EHOSTUNREACH:
			retval = -ENOLINK;
			break;
		default:
			netif_dbg(dev, rx_err, dev->net,
				  "rx submit, %d\n", retval);
			tasklet_schedule (&dev->bh);
			break;
		case 0:
			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
		}
	} else {
		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
		retval = -ENOLINK;
	}
	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
	if (retval) {
		dev_kfree_skb_any (skb);
		usb_free_urb (urb);
	}
	return retval;
}


/*-------------------------------------------------------------------------*/

static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
{
	if (dev->driver_info->rx_fixup &&
	    !dev->driver_info->rx_fixup (dev, skb)) {
		/* With RX_ASSEMBLE, rx_fixup() must update counters */
		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
			dev->net->stats.rx_errors++;
		goto done;
	}
	// else network stack removes extra byte if we forced a short packet

	/* all data was already cloned from skb inside the driver */
	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
		goto done;

	if (skb->len < ETH_HLEN) {
		dev->net->stats.rx_errors++;
		dev->net->stats.rx_length_errors++;
		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
	} else {
		usbnet_skb_return(dev, skb);
		return;
	}

done:
	skb_queue_tail(&dev->done, skb);
}

/*-------------------------------------------------------------------------*/

static void rx_complete (struct urb *urb)
{
	struct sk_buff		*skb = (struct sk_buff *) urb->context;
	struct skb_data		*entry = (struct skb_data *) skb->cb;
	struct usbnet		*dev = entry->dev;
	int			urb_status = urb->status;
	enum skb_state		state;

	skb_put (skb, urb->actual_length);
	state = rx_done;
	entry->urb = NULL;

	switch (urb_status) {
	/* success */
	case 0:
		break;

	/* stalls need manual reset. this is rare ... except that
	 * when going through USB 2.0 TTs, unplug appears this way.
	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
	 * storm, recovering as needed.
	 */
	case -EPIPE:
		dev->net->stats.rx_errors++;
		usbnet_defer_kevent (dev, EVENT_RX_HALT);
		// FALLTHROUGH

	/* software-driven interface shutdown */
	case -ECONNRESET:		/* async unlink */
	case -ESHUTDOWN:		/* hardware gone */
		netif_dbg(dev, ifdown, dev->net,
			  "rx shutdown, code %d\n", urb_status);
		goto block;

	/* we get controller i/o faults during hub_wq disconnect() delays.
	 * throttle down resubmits, to avoid log floods; just temporarily,
	 * so we still recover when the fault isn't a hub_wq delay.
	 */
	case -EPROTO:
	case -ETIME:
	case -EILSEQ:
		dev->net->stats.rx_errors++;
		if (!timer_pending (&dev->delay)) {
			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
			netif_dbg(dev, link, dev->net,
				  "rx throttle %d\n", urb_status);
		}
block:
		state = rx_cleanup;
		entry->urb = urb;
		urb = NULL;
		break;

	/* data overrun ... flush fifo? */
	case -EOVERFLOW:
		dev->net->stats.rx_over_errors++;
		// FALLTHROUGH

	default:
		state = rx_cleanup;
		dev->net->stats.rx_errors++;
		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
		break;
	}

	/* stop rx if packet error rate is high */
	if (++dev->pkt_cnt > 30) {
		dev->pkt_cnt = 0;
		dev->pkt_err = 0;
	} else {
		if (state == rx_cleanup)
			dev->pkt_err++;
		if (dev->pkt_err > 20)
			set_bit(EVENT_RX_KILL, &dev->flags);
	}

	state = defer_bh(dev, skb, &dev->rxq, state);

	if (urb) {
		if (netif_running (dev->net) &&
		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
		    state != unlink_start) {
			rx_submit (dev, urb, GFP_ATOMIC);
			usb_mark_last_busy(dev->udev);
			return;
		}
		usb_free_urb (urb);
	}
	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
}

/*-------------------------------------------------------------------------*/
void usbnet_pause_rx(struct usbnet *dev)
{
	set_bit(EVENT_RX_PAUSED, &dev->flags);

	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
}
EXPORT_SYMBOL_GPL(usbnet_pause_rx);

void usbnet_resume_rx(struct usbnet *dev)
{
	struct sk_buff *skb;
	int num = 0;

	clear_bit(EVENT_RX_PAUSED, &dev->flags);

	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
		usbnet_skb_return(dev, skb);
		num++;
	}

	tasklet_schedule(&dev->bh);

	netif_dbg(dev, rx_status, dev->net,
		  "paused rx queue disabled, %d skbs requeued\n", num);
}
EXPORT_SYMBOL_GPL(usbnet_resume_rx);

void usbnet_purge_paused_rxq(struct usbnet *dev)
{
	skb_queue_purge(&dev->rxq_pause);
}
EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);

/*-------------------------------------------------------------------------*/

// unlink pending rx/tx; completion handlers do all other cleanup

static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
{
	unsigned long		flags;
	struct sk_buff		*skb;
	int			count = 0;

	spin_lock_irqsave (&q->lock, flags);
	while (!skb_queue_empty(q)) {
		struct skb_data		*entry;
		struct urb		*urb;
		int			retval;

		skb_queue_walk(q, skb) {
			entry = (struct skb_data *) skb->cb;
			if (entry->state != unlink_start)
				goto found;
		}
		break;
found:
		entry->state = unlink_start;
		urb = entry->urb;

		/*
		 * Get reference count of the URB to avoid it to be
		 * freed during usb_unlink_urb, which may trigger
		 * use-after-free problem inside usb_unlink_urb since
		 * usb_unlink_urb is always racing with .complete
		 * handler(include defer_bh).
		 */
		usb_get_urb(urb);
		spin_unlock_irqrestore(&q->lock, flags);
		// during some PM-driven resume scenarios,
		// these (async) unlinks complete immediately
		retval = usb_unlink_urb (urb);
		if (retval != -EINPROGRESS && retval != 0)
			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
		else
			count++;
		usb_put_urb(urb);
		spin_lock_irqsave(&q->lock, flags);
	}
	spin_unlock_irqrestore (&q->lock, flags);
	return count;
}

// Flush all pending rx urbs
// minidrivers may need to do this when the MTU changes

void usbnet_unlink_rx_urbs(struct usbnet *dev)
{
	if (netif_running(dev->net)) {
		(void) unlink_urbs (dev, &dev->rxq);
		tasklet_schedule(&dev->bh);
	}
}
EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);

/*-------------------------------------------------------------------------*/

// precondition: never called in_interrupt
static void usbnet_terminate_urbs(struct usbnet *dev)
{
	DECLARE_WAITQUEUE(wait, current);
	int temp;

	/* ensure there are no more active urbs */
	add_wait_queue(&dev->wait, &wait);
	set_current_state(TASK_UNINTERRUPTIBLE);
	temp = unlink_urbs(dev, &dev->txq) +
		unlink_urbs(dev, &dev->rxq);

	/* maybe wait for deletions to finish. */
	while (!skb_queue_empty(&dev->rxq)
		&& !skb_queue_empty(&dev->txq)
		&& !skb_queue_empty(&dev->done)) {
			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
			set_current_state(TASK_UNINTERRUPTIBLE);
			netif_dbg(dev, ifdown, dev->net,
				  "waited for %d urb completions\n", temp);
	}
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&dev->wait, &wait);
}

int usbnet_stop (struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);
	struct driver_info	*info = dev->driver_info;
	int			retval, pm;

	clear_bit(EVENT_DEV_OPEN, &dev->flags);
	netif_stop_queue (net);

	netif_info(dev, ifdown, dev->net,
		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
		   net->stats.rx_packets, net->stats.tx_packets,
		   net->stats.rx_errors, net->stats.tx_errors);

	/* to not race resume */
	pm = usb_autopm_get_interface(dev->intf);
	/* allow minidriver to stop correctly (wireless devices to turn off
	 * radio etc) */
	if (info->stop) {
		retval = info->stop(dev);
		if (retval < 0)
			netif_info(dev, ifdown, dev->net,
				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
				   retval,
				   dev->udev->bus->bus_name, dev->udev->devpath,
				   info->description);
	}

	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
		usbnet_terminate_urbs(dev);

	usbnet_status_stop(dev);

	usbnet_purge_paused_rxq(dev);

	/* deferred work (task, timer, softirq) must also stop.
	 * can't flush_scheduled_work() until we drop rtnl (later),
	 * else workers could deadlock; so make workers a NOP.
	 */
	dev->flags = 0;
	del_timer_sync (&dev->delay);
	tasklet_kill (&dev->bh);
	if (!pm)
		usb_autopm_put_interface(dev->intf);

	if (info->manage_power &&
	    !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags))
		info->manage_power(dev, 0);
	else
		usb_autopm_put_interface(dev->intf);

	return 0;
}
EXPORT_SYMBOL_GPL(usbnet_stop);

/*-------------------------------------------------------------------------*/

// posts reads, and enables write queuing

// precondition: never called in_interrupt

int usbnet_open (struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);
	int			retval;
	struct driver_info	*info = dev->driver_info;

	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
		netif_info(dev, ifup, dev->net,
			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
			   retval,
			   dev->udev->bus->bus_name,
			   dev->udev->devpath,
			   info->description);
		goto done_nopm;
	}

	// put into "known safe" state
	if (info->reset && (retval = info->reset (dev)) < 0) {
		netif_info(dev, ifup, dev->net,
			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
			   retval,
			   dev->udev->bus->bus_name,
			   dev->udev->devpath,
			   info->description);
		goto done;
	}

	/* hard_mtu or rx_urb_size may change in reset() */
	usbnet_update_max_qlen(dev);

	// insist peer be connected
	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
		goto done;
	}

	/* start any status interrupt transfer */
	if (dev->interrupt) {
		retval = usbnet_status_start(dev, GFP_KERNEL);
		if (retval < 0) {
			netif_err(dev, ifup, dev->net,
				  "intr submit %d\n", retval);
			goto done;
		}
	}

	set_bit(EVENT_DEV_OPEN, &dev->flags);
	netif_start_queue (net);
	netif_info(dev, ifup, dev->net,
		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
		   dev->net->mtu,
		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
		   "simple");

	/* reset rx error state */
	dev->pkt_cnt = 0;
	dev->pkt_err = 0;
	clear_bit(EVENT_RX_KILL, &dev->flags);

	// delay posting reads until we're fully open
	tasklet_schedule (&dev->bh);
	if (info->manage_power) {
		retval = info->manage_power(dev, 1);
		if (retval < 0) {
			retval = 0;
			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
		} else {
			usb_autopm_put_interface(dev->intf);
		}
	}
	return retval;
done:
	usb_autopm_put_interface(dev->intf);
done_nopm:
	return retval;
}
EXPORT_SYMBOL_GPL(usbnet_open);

/*-------------------------------------------------------------------------*/

/* ethtool methods; minidrivers may need to add some more, but
 * they'll probably want to use this base set.
 */

int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
{
	struct usbnet *dev = netdev_priv(net);

	if (!dev->mii.mdio_read)
		return -EOPNOTSUPP;

	return mii_ethtool_gset(&dev->mii, cmd);
}
EXPORT_SYMBOL_GPL(usbnet_get_settings);

int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
{
	struct usbnet *dev = netdev_priv(net);
	int retval;

	if (!dev->mii.mdio_write)
		return -EOPNOTSUPP;

	retval = mii_ethtool_sset(&dev->mii, cmd);

	/* link speed/duplex might have changed */
	if (dev->driver_info->link_reset)
		dev->driver_info->link_reset(dev);

	/* hard_mtu or rx_urb_size may change in link_reset() */
	usbnet_update_max_qlen(dev);

	return retval;

}
EXPORT_SYMBOL_GPL(usbnet_set_settings);

u32 usbnet_get_link (struct net_device *net)
{
	struct usbnet *dev = netdev_priv(net);

	/* If a check_connect is defined, return its result */
	if (dev->driver_info->check_connect)
		return dev->driver_info->check_connect (dev) == 0;

	/* if the device has mii operations, use those */
	if (dev->mii.mdio_read)
		return mii_link_ok(&dev->mii);

	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
	return ethtool_op_get_link(net);
}
EXPORT_SYMBOL_GPL(usbnet_get_link);

int usbnet_nway_reset(struct net_device *net)
{
	struct usbnet *dev = netdev_priv(net);

	if (!dev->mii.mdio_write)
		return -EOPNOTSUPP;

	return mii_nway_restart(&dev->mii);
}
EXPORT_SYMBOL_GPL(usbnet_nway_reset);

void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
{
	struct usbnet *dev = netdev_priv(net);

	strlcpy (info->driver, dev->driver_name, sizeof info->driver);
	strlcpy (info->version, DRIVER_VERSION, sizeof info->version);
	strlcpy (info->fw_version, dev->driver_info->description,
		sizeof info->fw_version);
	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
}
EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);

u32 usbnet_get_msglevel (struct net_device *net)
{
	struct usbnet *dev = netdev_priv(net);

	return dev->msg_enable;
}
EXPORT_SYMBOL_GPL(usbnet_get_msglevel);

void usbnet_set_msglevel (struct net_device *net, u32 level)
{
	struct usbnet *dev = netdev_priv(net);

	dev->msg_enable = level;
}
EXPORT_SYMBOL_GPL(usbnet_set_msglevel);

/* drivers may override default ethtool_ops in their bind() routine */
static const struct ethtool_ops usbnet_ethtool_ops = {
	.get_settings		= usbnet_get_settings,
	.set_settings		= usbnet_set_settings,
	.get_link		= usbnet_get_link,
	.nway_reset		= usbnet_nway_reset,
	.get_drvinfo		= usbnet_get_drvinfo,
	.get_msglevel		= usbnet_get_msglevel,
	.set_msglevel		= usbnet_set_msglevel,
	.get_ts_info		= ethtool_op_get_ts_info,
};

/*-------------------------------------------------------------------------*/

static void __handle_link_change(struct usbnet *dev)
{
	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
		return;

	if (!netif_carrier_ok(dev->net)) {
		/* kill URBs for reading packets to save bus bandwidth */
		unlink_urbs(dev, &dev->rxq);

		/*
		 * tx_timeout will unlink URBs for sending packets and
		 * tx queue is stopped by netcore after link becomes off
		 */
	} else {
		/* submitting URBs for reading packets */
		tasklet_schedule(&dev->bh);
	}

	/* hard_mtu or rx_urb_size may change during link change */
	usbnet_update_max_qlen(dev);

	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
}

static void usbnet_set_rx_mode(struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);

	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
}

static void __handle_set_rx_mode(struct usbnet *dev)
{
	if (dev->driver_info->set_rx_mode)
		(dev->driver_info->set_rx_mode)(dev);

	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
}

/* work that cannot be done in interrupt context uses keventd.
 *
 * NOTE:  with 2.5 we could do more of this using completion callbacks,
 * especially now that control transfers can be queued.
 */
static void
kevent (struct work_struct *work)
{
	struct usbnet		*dev =
		container_of(work, struct usbnet, kevent);
	int			status;

	/* usb_clear_halt() needs a thread context */
	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
		unlink_urbs (dev, &dev->txq);
		status = usb_autopm_get_interface(dev->intf);
		if (status < 0)
			goto fail_pipe;
		status = usb_clear_halt (dev->udev, dev->out);
		usb_autopm_put_interface(dev->intf);
		if (status < 0 &&
		    status != -EPIPE &&
		    status != -ESHUTDOWN) {
			if (netif_msg_tx_err (dev))
fail_pipe:
				netdev_err(dev->net, "can't clear tx halt, status %d\n",
					   status);
		} else {
			clear_bit (EVENT_TX_HALT, &dev->flags);
			if (status != -ESHUTDOWN)
				netif_wake_queue (dev->net);
		}
	}
	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
		unlink_urbs (dev, &dev->rxq);
		status = usb_autopm_get_interface(dev->intf);
		if (status < 0)
			goto fail_halt;
		status = usb_clear_halt (dev->udev, dev->in);
		usb_autopm_put_interface(dev->intf);
		if (status < 0 &&
		    status != -EPIPE &&
		    status != -ESHUTDOWN) {
			if (netif_msg_rx_err (dev))
fail_halt:
				netdev_err(dev->net, "can't clear rx halt, status %d\n",
					   status);
		} else {
			clear_bit (EVENT_RX_HALT, &dev->flags);
			tasklet_schedule (&dev->bh);
		}
	}

	/* tasklet could resubmit itself forever if memory is tight */
	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
		struct urb	*urb = NULL;
		int resched = 1;

		if (netif_running (dev->net))
			urb = usb_alloc_urb (0, GFP_KERNEL);
		else
			clear_bit (EVENT_RX_MEMORY, &dev->flags);
		if (urb != NULL) {
			clear_bit (EVENT_RX_MEMORY, &dev->flags);
			status = usb_autopm_get_interface(dev->intf);
			if (status < 0) {
				usb_free_urb(urb);
				goto fail_lowmem;
			}
			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
				resched = 0;
			usb_autopm_put_interface(dev->intf);
fail_lowmem:
			if (resched)
				tasklet_schedule (&dev->bh);
		}
	}

	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
		struct driver_info	*info = dev->driver_info;
		int			retval = 0;

		clear_bit (EVENT_LINK_RESET, &dev->flags);
		status = usb_autopm_get_interface(dev->intf);
		if (status < 0)
			goto skip_reset;
		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
			usb_autopm_put_interface(dev->intf);
skip_reset:
			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
				    retval,
				    dev->udev->bus->bus_name,
				    dev->udev->devpath,
				    info->description);
		} else {
			usb_autopm_put_interface(dev->intf);
		}

		/* handle link change from link resetting */
		__handle_link_change(dev);
	}

	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
		__handle_link_change(dev);

	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
		__handle_set_rx_mode(dev);


	if (dev->flags)
		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
}

/*-------------------------------------------------------------------------*/

static void tx_complete (struct urb *urb)
{
	struct sk_buff		*skb = (struct sk_buff *) urb->context;
	struct skb_data		*entry = (struct skb_data *) skb->cb;
	struct usbnet		*dev = entry->dev;

	if (urb->status == 0) {
		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
			dev->net->stats.tx_packets++;
		dev->net->stats.tx_bytes += entry->length;
	} else {
		dev->net->stats.tx_errors++;

		switch (urb->status) {
		case -EPIPE:
			usbnet_defer_kevent (dev, EVENT_TX_HALT);
			break;

		/* software-driven interface shutdown */
		case -ECONNRESET:		// async unlink
		case -ESHUTDOWN:		// hardware gone
			break;

		/* like rx, tx gets controller i/o faults during hub_wq
		 * delays and so it uses the same throttling mechanism.
		 */
		case -EPROTO:
		case -ETIME:
		case -EILSEQ:
			usb_mark_last_busy(dev->udev);
			if (!timer_pending (&dev->delay)) {
				mod_timer (&dev->delay,
					jiffies + THROTTLE_JIFFIES);
				netif_dbg(dev, link, dev->net,
					  "tx throttle %d\n", urb->status);
			}
			netif_stop_queue (dev->net);
			break;
		default:
			netif_dbg(dev, tx_err, dev->net,
				  "tx err %d\n", entry->urb->status);
			break;
		}
	}

	usb_autopm_put_interface_async(dev->intf);
	(void) defer_bh(dev, skb, &dev->txq, tx_done);
}

/*-------------------------------------------------------------------------*/

void usbnet_tx_timeout (struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);

	unlink_urbs (dev, &dev->txq);
	tasklet_schedule (&dev->bh);
	/* this needs to be handled individually because the generic layer
	 * doesn't know what is sufficient and could not restore private
	 * information if a remedy of an unconditional reset were used.
	 */
	if (dev->driver_info->recover)
		(dev->driver_info->recover)(dev);
}
EXPORT_SYMBOL_GPL(usbnet_tx_timeout);

/*-------------------------------------------------------------------------*/

static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
{
	unsigned num_sgs, total_len = 0;
	int i, s = 0;

	num_sgs = skb_shinfo(skb)->nr_frags + 1;
	if (num_sgs == 1)
		return 0;

	/* reserve one for zero packet */
	urb->sg = kmalloc((num_sgs + 1) * sizeof(struct scatterlist),
			  GFP_ATOMIC);
	if (!urb->sg)
		return -ENOMEM;

	urb->num_sgs = num_sgs;
	sg_init_table(urb->sg, urb->num_sgs + 1);

	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
	total_len += skb_headlen(skb);

	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
		struct skb_frag_struct *f = &skb_shinfo(skb)->frags[i];

		total_len += skb_frag_size(f);
		sg_set_page(&urb->sg[i + s], f->page.p, f->size,
				f->page_offset);
	}
	urb->transfer_buffer_length = total_len;

	return 1;
}

netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
				     struct net_device *net)
{
	struct usbnet		*dev = netdev_priv(net);
	int			length;
	struct urb		*urb = NULL;
	struct skb_data		*entry;
	struct driver_info	*info = dev->driver_info;
	unsigned long		flags;
	int retval;

	if (skb)
		skb_tx_timestamp(skb);

	// some devices want funky USB-level framing, for
	// win32 driver (usually) and/or hardware quirks
	if (info->tx_fixup) {
		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
		if (!skb) {
			/* packet collected; minidriver waiting for more */
			if (info->flags & FLAG_MULTI_PACKET)
				goto not_drop;
			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
			goto drop;
		}
	}

	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
		netif_dbg(dev, tx_err, dev->net, "no urb\n");
		goto drop;
	}

	entry = (struct skb_data *) skb->cb;
	entry->urb = urb;
	entry->dev = dev;

	usb_fill_bulk_urb (urb, dev->udev, dev->out,
			skb->data, skb->len, tx_complete, skb);
	if (dev->can_dma_sg) {
		if (build_dma_sg(skb, urb) < 0)
			goto drop;
	}
	length = urb->transfer_buffer_length;

	/* don't assume the hardware handles USB_ZERO_PACKET
	 * NOTE:  strictly conforming cdc-ether devices should expect
	 * the ZLP here, but ignore the one-byte packet.
	 * NOTE2: CDC NCM specification is different from CDC ECM when
	 * handling ZLP/short packets, so cdc_ncm driver will make short
	 * packet itself if needed.
	 */
	if (length % dev->maxpacket == 0) {
		if (!(info->flags & FLAG_SEND_ZLP)) {
			if (!(info->flags & FLAG_MULTI_PACKET)) {
				length++;
				if (skb_tailroom(skb) && !urb->num_sgs) {
					skb->data[skb->len] = 0;
					__skb_put(skb, 1);
				} else if (urb->num_sgs)
					sg_set_buf(&urb->sg[urb->num_sgs++],
							dev->padding_pkt, 1);
			}
		} else
			urb->transfer_flags |= URB_ZERO_PACKET;
	}
	entry->length = urb->transfer_buffer_length = length;

	spin_lock_irqsave(&dev->txq.lock, flags);
	retval = usb_autopm_get_interface_async(dev->intf);
	if (retval < 0) {
		spin_unlock_irqrestore(&dev->txq.lock, flags);
		goto drop;
	}

#ifdef CONFIG_PM
	/* if this triggers the device is still a sleep */
	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
		/* transmission will be done in resume */
		usb_anchor_urb(urb, &dev->deferred);
		/* no use to process more packets */
		netif_stop_queue(net);
		usb_put_urb(urb);
		spin_unlock_irqrestore(&dev->txq.lock, flags);
		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
		goto deferred;
	}
#endif

	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
	case -EPIPE:
		netif_stop_queue (net);
		usbnet_defer_kevent (dev, EVENT_TX_HALT);
		usb_autopm_put_interface_async(dev->intf);
		break;
	default:
		usb_autopm_put_interface_async(dev->intf);
		netif_dbg(dev, tx_err, dev->net,
			  "tx: submit urb err %d\n", retval);
		break;
	case 0:
		net->trans_start = jiffies;
		__usbnet_queue_skb(&dev->txq, skb, tx_start);
		if (dev->txq.qlen >= TX_QLEN (dev))
			netif_stop_queue (net);
	}
	spin_unlock_irqrestore (&dev->txq.lock, flags);

	if (retval) {
		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
drop:
		dev->net->stats.tx_dropped++;
not_drop:
		if (skb)
			dev_kfree_skb_any (skb);
		if (urb) {
			kfree(urb->sg);
			usb_free_urb(urb);
		}
	} else
		netif_dbg(dev, tx_queued, dev->net,
			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
#ifdef CONFIG_PM
deferred:
#endif
	return NETDEV_TX_OK;
}
EXPORT_SYMBOL_GPL(usbnet_start_xmit);

static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
{
	struct urb	*urb;
	int		i;
	int		ret = 0;

	/* don't refill the queue all at once */
	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
		urb = usb_alloc_urb(0, flags);
		if (urb != NULL) {
			ret = rx_submit(dev, urb, flags);
			if (ret)
				goto err;
		} else {
			ret = -ENOMEM;
			goto err;
		}
	}
err:
	return ret;
}

/*-------------------------------------------------------------------------*/

// tasklet (work deferred from completions, in_irq) or timer

static void usbnet_bh (unsigned long param)
{
	struct usbnet		*dev = (struct usbnet *) param;
	struct sk_buff		*skb;
	struct skb_data		*entry;

	while ((skb = skb_dequeue (&dev->done))) {
		entry = (struct skb_data *) skb->cb;
		switch (entry->state) {
		case rx_done:
			entry->state = rx_cleanup;
			rx_process (dev, skb);
			continue;
		case tx_done:
			kfree(entry->urb->sg);
		case rx_cleanup:
			usb_free_urb (entry->urb);
			dev_kfree_skb (skb);
			continue;
		default:
			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
		}
	}

	/* restart RX again after disabling due to high error rate */
	clear_bit(EVENT_RX_KILL, &dev->flags);

	/* waiting for all pending urbs to complete?
	 * only then can we forgo submitting anew
	 */
	if (waitqueue_active(&dev->wait)) {
		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
			wake_up_all(&dev->wait);

	// or are we maybe short a few urbs?
	} else if (netif_running (dev->net) &&
		   netif_device_present (dev->net) &&
		   netif_carrier_ok(dev->net) &&
		   !timer_pending (&dev->delay) &&
		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
		int	temp = dev->rxq.qlen;

		if (temp < RX_QLEN(dev)) {
			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
				return;
			if (temp != dev->rxq.qlen)
				netif_dbg(dev, link, dev->net,
					  "rxqlen %d --> %d\n",
					  temp, dev->rxq.qlen);
			if (dev->rxq.qlen < RX_QLEN(dev))
				tasklet_schedule (&dev->bh);
		}
		if (dev->txq.qlen < TX_QLEN (dev))
			netif_wake_queue (dev->net);
	}
}


/*-------------------------------------------------------------------------
 *
 * USB Device Driver support
 *
 *-------------------------------------------------------------------------*/

// precondition: never called in_interrupt

void usbnet_disconnect (struct usb_interface *intf)
{
	struct usbnet		*dev;
	struct usb_device	*xdev;
	struct net_device	*net;

	dev = usb_get_intfdata(intf);
	usb_set_intfdata(intf, NULL);
	if (!dev)
		return;

	xdev = interface_to_usbdev (intf);

	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
		   intf->dev.driver->name,
		   xdev->bus->bus_name, xdev->devpath,
		   dev->driver_info->description);

	net = dev->net;
	unregister_netdev (net);

	cancel_work_sync(&dev->kevent);

	usb_scuttle_anchored_urbs(&dev->deferred);

	if (dev->driver_info->unbind)
		dev->driver_info->unbind (dev, intf);

	usb_kill_urb(dev->interrupt);
	usb_free_urb(dev->interrupt);
	kfree(dev->padding_pkt);

	free_netdev(net);
}
EXPORT_SYMBOL_GPL(usbnet_disconnect);

static const struct net_device_ops usbnet_netdev_ops = {
	.ndo_open		= usbnet_open,
	.ndo_stop		= usbnet_stop,
	.ndo_start_xmit		= usbnet_start_xmit,
	.ndo_tx_timeout		= usbnet_tx_timeout,
	.ndo_set_rx_mode	= usbnet_set_rx_mode,
	.ndo_change_mtu		= usbnet_change_mtu,
	.ndo_set_mac_address 	= eth_mac_addr,
	.ndo_validate_addr	= eth_validate_addr,
};

/*-------------------------------------------------------------------------*/

// precondition: never called in_interrupt

static struct device_type wlan_type = {
	.name	= "wlan",
};

static struct device_type wwan_type = {
	.name	= "wwan",
};

int
usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
{
	struct usbnet			*dev;
	struct net_device		*net;
	struct usb_host_interface	*interface;
	struct driver_info		*info;
	struct usb_device		*xdev;
	int				status;
	const char			*name;
	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);

	/* usbnet already took usb runtime pm, so have to enable the feature
	 * for usb interface, otherwise usb_autopm_get_interface may return
	 * failure if RUNTIME_PM is enabled.
	 */
	if (!driver->supports_autosuspend) {
		driver->supports_autosuspend = 1;
		pm_runtime_enable(&udev->dev);
	}

	name = udev->dev.driver->name;
	info = (struct driver_info *) prod->driver_info;
	if (!info) {
		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
		return -ENODEV;
	}
	xdev = interface_to_usbdev (udev);
	interface = udev->cur_altsetting;

	status = -ENOMEM;

	// set up our own records
	net = alloc_etherdev(sizeof(*dev));
	if (!net)
		goto out;

	/* netdev_printk() needs this so do it as early as possible */
	SET_NETDEV_DEV(net, &udev->dev);

	dev = netdev_priv(net);
	dev->udev = xdev;
	dev->intf = udev;
	dev->driver_info = info;
	dev->driver_name = name;
	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
	init_waitqueue_head(&dev->wait);
	skb_queue_head_init (&dev->rxq);
	skb_queue_head_init (&dev->txq);
	skb_queue_head_init (&dev->done);
	skb_queue_head_init(&dev->rxq_pause);
	dev->bh.func = usbnet_bh;
	dev->bh.data = (unsigned long) dev;
	INIT_WORK (&dev->kevent, kevent);
	init_usb_anchor(&dev->deferred);
	dev->delay.function = usbnet_bh;
	dev->delay.data = (unsigned long) dev;
	init_timer (&dev->delay);
	mutex_init (&dev->phy_mutex);
	mutex_init(&dev->interrupt_mutex);
	dev->interrupt_count = 0;

	dev->net = net;
	strcpy (net->name, "usb%d");
	memcpy (net->dev_addr, node_id, sizeof node_id);

	/* rx and tx sides can use different message sizes;
	 * bind() should set rx_urb_size in that case.
	 */
	dev->hard_mtu = net->mtu + net->hard_header_len;
#if 0
// dma_supported() is deeply broken on almost all architectures
	// possible with some EHCI controllers
	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
		net->features |= NETIF_F_HIGHDMA;
#endif

	net->netdev_ops = &usbnet_netdev_ops;
	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
	net->ethtool_ops = &usbnet_ethtool_ops;

	// allow device-specific bind/init procedures
	// NOTE net->name still not usable ...
	if (info->bind) {
		status = info->bind (dev, udev);
		if (status < 0)
			goto out1;

		// heuristic:  "usb%d" for links we know are two-host,
		// else "eth%d" when there's reasonable doubt.  userspace
		// can rename the link if it knows better.
		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
		     (net->dev_addr [0] & 0x02) == 0))
			strcpy (net->name, "eth%d");
		/* WLAN devices should always be named "wlan%d" */
		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
			strcpy(net->name, "wlan%d");
		/* WWAN devices should always be named "wwan%d" */
		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
			strcpy(net->name, "wwan%d");

		/* devices that cannot do ARP */
		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
			net->flags |= IFF_NOARP;

		/* maybe the remote can't receive an Ethernet MTU */
		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
			net->mtu = dev->hard_mtu - net->hard_header_len;
	} else if (!info->in || !info->out)
		status = usbnet_get_endpoints (dev, udev);
	else {
		dev->in = usb_rcvbulkpipe (xdev, info->in);
		dev->out = usb_sndbulkpipe (xdev, info->out);
		if (!(info->flags & FLAG_NO_SETINT))
			status = usb_set_interface (xdev,
				interface->desc.bInterfaceNumber,
				interface->desc.bAlternateSetting);
		else
			status = 0;

	}
	if (status >= 0 && dev->status)
		status = init_status (dev, udev);
	if (status < 0)
		goto out3;

	if (!dev->rx_urb_size)
		dev->rx_urb_size = dev->hard_mtu;
	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);

	/* let userspace know we have a random address */
	if (ether_addr_equal(net->dev_addr, node_id))
		net->addr_assign_type = NET_ADDR_RANDOM;

	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
		SET_NETDEV_DEVTYPE(net, &wlan_type);
	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
		SET_NETDEV_DEVTYPE(net, &wwan_type);

	/* initialize max rx_qlen and tx_qlen */
	usbnet_update_max_qlen(dev);

	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
		!(info->flags & FLAG_MULTI_PACKET)) {
		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
		if (!dev->padding_pkt) {
			status = -ENOMEM;
			goto out4;
		}
	}

	status = register_netdev (net);
	if (status)
		goto out5;
	netif_info(dev, probe, dev->net,
		   "register '%s' at usb-%s-%s, %s, %pM\n",
		   udev->dev.driver->name,
		   xdev->bus->bus_name, xdev->devpath,
		   dev->driver_info->description,
		   net->dev_addr);

	// ok, it's ready to go.
	usb_set_intfdata (udev, dev);

	netif_device_attach (net);

	if (dev->driver_info->flags & FLAG_LINK_INTR)
		usbnet_link_change(dev, 0, 0);

	return 0;

out5:
	kfree(dev->padding_pkt);
out4:
	usb_free_urb(dev->interrupt);
out3:
	if (info->unbind)
		info->unbind (dev, udev);
out1:
	free_netdev(net);
out:
	return status;
}
EXPORT_SYMBOL_GPL(usbnet_probe);

/*-------------------------------------------------------------------------*/

/*
 * suspend the whole driver as soon as the first interface is suspended
 * resume only when the last interface is resumed
 */

int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
{
	struct usbnet		*dev = usb_get_intfdata(intf);

	if (!dev->suspend_count++) {
		spin_lock_irq(&dev->txq.lock);
		/* don't autosuspend while transmitting */
		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
			dev->suspend_count--;
			spin_unlock_irq(&dev->txq.lock);
			return -EBUSY;
		} else {
			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
			spin_unlock_irq(&dev->txq.lock);
		}
		/*
		 * accelerate emptying of the rx and queues, to avoid
		 * having everything error out.
		 */
		netif_device_detach (dev->net);
		usbnet_terminate_urbs(dev);
		__usbnet_status_stop_force(dev);

		/*
		 * reattach so runtime management can use and
		 * wake the device
		 */
		netif_device_attach (dev->net);
	}
	return 0;
}
EXPORT_SYMBOL_GPL(usbnet_suspend);

int usbnet_resume (struct usb_interface *intf)
{
	struct usbnet		*dev = usb_get_intfdata(intf);
	struct sk_buff          *skb;
	struct urb              *res;
	int                     retval;

	if (!--dev->suspend_count) {
		/* resume interrupt URB if it was previously submitted */
		__usbnet_status_start_force(dev, GFP_NOIO);

		spin_lock_irq(&dev->txq.lock);
		while ((res = usb_get_from_anchor(&dev->deferred))) {

			skb = (struct sk_buff *)res->context;
			retval = usb_submit_urb(res, GFP_ATOMIC);
			if (retval < 0) {
				dev_kfree_skb_any(skb);
				kfree(res->sg);
				usb_free_urb(res);
				usb_autopm_put_interface_async(dev->intf);
			} else {
				dev->net->trans_start = jiffies;
				__skb_queue_tail(&dev->txq, skb);
			}
		}

		smp_mb();
		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
		spin_unlock_irq(&dev->txq.lock);

		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
			/* handle remote wakeup ASAP
			 * we cannot race against stop
			 */
			if (netif_device_present(dev->net) &&
				!timer_pending(&dev->delay) &&
				!test_bit(EVENT_RX_HALT, &dev->flags))
					rx_alloc_submit(dev, GFP_NOIO);

			if (!(dev->txq.qlen >= TX_QLEN(dev)))
				netif_tx_wake_all_queues(dev->net);
			tasklet_schedule (&dev->bh);
		}
	}

	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
		usb_autopm_get_interface_no_resume(intf);

	return 0;
}
EXPORT_SYMBOL_GPL(usbnet_resume);

/*
 * Either a subdriver implements manage_power, then it is assumed to always
 * be ready to be suspended or it reports the readiness to be suspended
 * explicitly
 */
void usbnet_device_suggests_idle(struct usbnet *dev)
{
	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
		dev->intf->needs_remote_wakeup = 1;
		usb_autopm_put_interface_async(dev->intf);
	}
}
EXPORT_SYMBOL(usbnet_device_suggests_idle);

/*
 * For devices that can do without special commands
 */
int usbnet_manage_power(struct usbnet *dev, int on)
{
	dev->intf->needs_remote_wakeup = on;
	return 0;
}
EXPORT_SYMBOL(usbnet_manage_power);

void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
{
	/* update link after link is reseted */
	if (link && !need_reset)
		netif_carrier_on(dev->net);
	else
		netif_carrier_off(dev->net);

	if (need_reset && link)
		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
	else
		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
}
EXPORT_SYMBOL(usbnet_link_change);

/*-------------------------------------------------------------------------*/
static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
			     u16 value, u16 index, void *data, u16 size)
{
	void *buf = NULL;
	int err = -ENOMEM;

	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
		   " value=0x%04x index=0x%04x size=%d\n",
		   cmd, reqtype, value, index, size);

	if (data) {
		buf = kmalloc(size, GFP_KERNEL);
		if (!buf)
			goto out;
	}

	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
			      cmd, reqtype, value, index, buf, size,
			      USB_CTRL_GET_TIMEOUT);
	if (err > 0 && err <= size)
		memcpy(data, buf, err);
	kfree(buf);
out:
	return err;
}

static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
			      u16 value, u16 index, const void *data,
			      u16 size)
{
	void *buf = NULL;
	int err = -ENOMEM;

	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
		   " value=0x%04x index=0x%04x size=%d\n",
		   cmd, reqtype, value, index, size);

	if (data) {
		buf = kmemdup(data, size, GFP_KERNEL);
		if (!buf)
			goto out;
	}

	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
			      cmd, reqtype, value, index, buf, size,
			      USB_CTRL_SET_TIMEOUT);
	kfree(buf);

out:
	return err;
}

/*
 * The function can't be called inside suspend/resume callback,
 * otherwise deadlock will be caused.
 */
int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
		    u16 value, u16 index, void *data, u16 size)
{
	int ret;

	if (usb_autopm_get_interface(dev->intf) < 0)
		return -ENODEV;
	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
				data, size);
	usb_autopm_put_interface(dev->intf);
	return ret;
}
EXPORT_SYMBOL_GPL(usbnet_read_cmd);

/*
 * The function can't be called inside suspend/resume callback,
 * otherwise deadlock will be caused.
 */
int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
		     u16 value, u16 index, const void *data, u16 size)
{
	int ret;

	if (usb_autopm_get_interface(dev->intf) < 0)
		return -ENODEV;
	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
				 data, size);
	usb_autopm_put_interface(dev->intf);
	return ret;
}
EXPORT_SYMBOL_GPL(usbnet_write_cmd);

/*
 * The function can be called inside suspend/resume callback safely
 * and should only be called by suspend/resume callback generally.
 */
int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
			  u16 value, u16 index, void *data, u16 size)
{
	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
				 data, size);
}
EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);

/*
 * The function can be called inside suspend/resume callback safely
 * and should only be called by suspend/resume callback generally.
 */
int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
			  u16 value, u16 index, const void *data,
			  u16 size)
{
	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
				  data, size);
}
EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);

static void usbnet_async_cmd_cb(struct urb *urb)
{
	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
	int status = urb->status;

	if (status < 0)
		dev_dbg(&urb->dev->dev, "%s failed with %d",
			__func__, status);

	kfree(req);
	usb_free_urb(urb);
}

/*
 * The caller must make sure that device can't be put into suspend
 * state until the control URB completes.
 */
int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
			   u16 value, u16 index, const void *data, u16 size)
{
	struct usb_ctrlrequest *req = NULL;
	struct urb *urb;
	int err = -ENOMEM;
	void *buf = NULL;

	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
		   " value=0x%04x index=0x%04x size=%d\n",
		   cmd, reqtype, value, index, size);

	urb = usb_alloc_urb(0, GFP_ATOMIC);
	if (!urb) {
		netdev_err(dev->net, "Error allocating URB in"
			   " %s!\n", __func__);
		goto fail;
	}

	if (data) {
		buf = kmemdup(data, size, GFP_ATOMIC);
		if (!buf) {
			netdev_err(dev->net, "Error allocating buffer"
				   " in %s!\n", __func__);
			goto fail_free;
		}
	}

	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
	if (!req)
		goto fail_free_buf;

	req->bRequestType = reqtype;
	req->bRequest = cmd;
	req->wValue = cpu_to_le16(value);
	req->wIndex = cpu_to_le16(index);
	req->wLength = cpu_to_le16(size);

	usb_fill_control_urb(urb, dev->udev,
			     usb_sndctrlpipe(dev->udev, 0),
			     (void *)req, buf, size,
			     usbnet_async_cmd_cb, req);
	urb->transfer_flags |= URB_FREE_BUFFER;

	err = usb_submit_urb(urb, GFP_ATOMIC);
	if (err < 0) {
		netdev_err(dev->net, "Error submitting the control"
			   " message: status=%d\n", err);
		goto fail_free;
	}
	return 0;

fail_free_buf:
	kfree(buf);
fail_free:
	kfree(req);
	usb_free_urb(urb);
fail:
	return err;

}
EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
/*-------------------------------------------------------------------------*/

static int __init usbnet_init(void)
{
	/* Compiler should optimize this out. */
	BUILD_BUG_ON(
		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));

	eth_random_addr(node_id);
	return 0;
}
module_init(usbnet_init);

static void __exit usbnet_exit(void)
{
}
module_exit(usbnet_exit);

MODULE_AUTHOR("David Brownell");
MODULE_DESCRIPTION("USB network driver framework");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud