summaryrefslogtreecommitdiff
path: root/drivers/usb/misc/auerswald.c
blob: 1fef36e71c573ed10dc05b2de5240816e87fa0c5 (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
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
/*****************************************************************************/
/*
 *      auerswald.c  --  Auerswald PBX/System Telephone usb driver.
 *
 *      Copyright (C) 2001  Wolfgang Mües (wolfgang@iksw-muees.de)
 *
 *      Very much code of this driver is borrowed from dabusb.c (Deti Fliegl)
 *      and from the USB Skeleton driver (Greg Kroah-Hartman). Thank you.
 *
 *      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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
 /*****************************************************************************/

/* Standard Linux module include files */
#include <asm/uaccess.h>
#include <asm/byteorder.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/usb.h>

/*-------------------------------------------------------------------*/
/* Debug support 						     */
#ifdef DEBUG
#define dump( adr, len) \
do {			\
	unsigned int u;	\
	printk (KERN_DEBUG); \
	for (u = 0; u < len; u++) \
		printk (" %02X", adr[u] & 0xFF); \
	printk ("\n"); \
} while (0)
#else
#define dump( adr, len)
#endif

/*-------------------------------------------------------------------*/
/* Version Information */
#define DRIVER_VERSION "0.9.11"
#define DRIVER_AUTHOR  "Wolfgang Mües <wolfgang@iksw-muees.de>"
#define DRIVER_DESC    "Auerswald PBX/System Telephone usb driver"

/*-------------------------------------------------------------------*/
/* Private declarations for Auerswald USB driver                     */

/* Auerswald Vendor ID */
#define ID_AUERSWALD  	0x09BF

#define AUER_MINOR_BASE	112	/* auerswald driver minor number */

/* we can have up to this number of device plugged in at once */
#define AUER_MAX_DEVICES 16


/* Number of read buffers for each device */
#define AU_RBUFFERS     10

/* Number of chain elements for each control chain */
#define AUCH_ELEMENTS   20

/* Number of retries in communication */
#define AU_RETRIES	10

/*-------------------------------------------------------------------*/
/* vendor specific protocol                                          */
/* Header Byte */
#define AUH_INDIRMASK   0x80    /* mask for direct/indirect bit */
#define AUH_DIRECT      0x00    /* data is for USB device */
#define AUH_INDIRECT    0x80    /* USB device is relay */

#define AUH_SPLITMASK   0x40    /* mask for split bit */
#define AUH_UNSPLIT     0x00    /* data block is full-size */
#define AUH_SPLIT       0x40    /* data block is part of a larger one,
                                   split-byte follows */

#define AUH_TYPEMASK    0x3F    /* mask for type of data transfer */
#define AUH_TYPESIZE    0x40    /* different types */
#define AUH_DCHANNEL    0x00    /* D channel data */
#define AUH_B1CHANNEL   0x01    /* B1 channel transparent */
#define AUH_B2CHANNEL   0x02    /* B2 channel transparent */
/*                0x03..0x0F       reserved for driver internal use */
#define AUH_COMMAND     0x10    /* Command channel */
#define AUH_BPROT       0x11    /* Configuration block protocol */
#define AUH_DPROTANA    0x12    /* D channel protocol analyzer */
#define AUH_TAPI        0x13    /* telephone api data (ATD) */
/*                0x14..0x3F       reserved for other protocols */
#define AUH_UNASSIGNED  0xFF    /* if char device has no assigned service */
#define AUH_FIRSTUSERCH 0x11    /* first channel which is available for driver users */

#define AUH_SIZE	1 	/* Size of Header Byte */

/* Split Byte. Only present if split bit in header byte set.*/
#define AUS_STARTMASK   0x80    /* mask for first block of splitted frame */
#define AUS_FIRST       0x80    /* first block */
#define AUS_FOLLOW      0x00    /* following block */

#define AUS_ENDMASK     0x40    /* mask for last block of splitted frame */
#define AUS_END         0x40    /* last block */
#define AUS_NOEND       0x00    /* not the last block */

#define AUS_LENMASK     0x3F    /* mask for block length information */

/* Request types */
#define AUT_RREQ        (USB_DIR_IN  | USB_TYPE_VENDOR | USB_RECIP_OTHER)   /* Read Request */
#define AUT_WREQ        (USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER)   /* Write Request */

/* Vendor Requests */
#define AUV_GETINFO     0x00    /* GetDeviceInfo */
#define AUV_WBLOCK      0x01    /* Write Block */
#define AUV_RBLOCK      0x02    /* Read Block */
#define AUV_CHANNELCTL  0x03    /* Channel Control */
#define AUV_DUMMY	0x04	/* Dummy Out for retry */

/* Device Info Types */
#define AUDI_NUMBCH     0x0000  /* Number of supported B channels */
#define AUDI_OUTFSIZE   0x0001  /* Size of OUT B channel fifos */
#define AUDI_MBCTRANS   0x0002  /* max. Blocklength of control transfer */

/* Interrupt endpoint definitions */
#define AU_IRQENDP      1       /* Endpoint number */
#define AU_IRQCMDID     16      /* Command-block ID */
#define AU_BLOCKRDY     0       /* Command: Block data ready on ctl endpoint */
#define AU_IRQMINSIZE	5	/* Nr. of bytes decoded in this driver */

/* Device String Descriptors */
#define AUSI_VENDOR   	1	/* "Auerswald GmbH & Co. KG" */
#define AUSI_DEVICE   	2	/* Name of the Device */
#define AUSI_SERIALNR 	3	/* Serial Number */
#define AUSI_MSN      	4	/* "MSN ..." (first) Multiple Subscriber Number */

#define AUSI_DLEN	100	/* Max. Length of Device Description */

#define AUV_RETRY	0x101	/* First Firmware version which can do control retries */

/*-------------------------------------------------------------------*/
/* External data structures / Interface                              */
typedef struct
{
	char __user *buf;	/* return buffer for string contents */
	unsigned int bsize;	/* size of return buffer */
} audevinfo_t,*paudevinfo_t;

/* IO controls */
#define IOCTL_AU_SLEN	  _IOR( 'U', 0xF0, int)         /* return the max. string descriptor length */
#define IOCTL_AU_DEVINFO  _IOWR('U', 0xF1, audevinfo_t) /* get name of a specific device */
#define IOCTL_AU_SERVREQ  _IOW( 'U', 0xF2, int) 	/* request a service channel */
#define IOCTL_AU_BUFLEN	  _IOR( 'U', 0xF3, int)         /* return the max. buffer length for the device */
#define IOCTL_AU_RXAVAIL  _IOR( 'U', 0xF4, int)         /* return != 0 if Receive Data available */
#define IOCTL_AU_CONNECT  _IOR( 'U', 0xF5, int)         /* return != 0 if connected to a service channel */
#define IOCTL_AU_TXREADY  _IOR( 'U', 0xF6, int)         /* return != 0 if Transmitt channel ready to send */
/*                              'U'  0xF7..0xFF reseved */

/*-------------------------------------------------------------------*/
/* Internal data structures                                          */

/* ..................................................................*/
/* urb chain element */
struct  auerchain;                      /* forward for circular reference */
typedef struct
{
        struct auerchain *chain;        /* pointer to the chain to which this element belongs */
        struct urb * urbp;                   /* pointer to attached urb */
        void *context;                  /* saved URB context */
        usb_complete_t complete;        /* saved URB completion function */
        struct list_head list;          /* to include element into a list */
} auerchainelement_t,*pauerchainelement_t;

/* urb chain */
typedef struct auerchain
{
        pauerchainelement_t active;     /* element which is submitted to urb */
	spinlock_t lock;                /* protection agains interrupts */
        struct list_head waiting_list;  /* list of waiting elements */
        struct list_head free_list;     /* list of available elements */
} auerchain_t,*pauerchain_t;

/* urb blocking completion helper struct */
typedef struct
{
	wait_queue_head_t wqh;    	/* wait for completion */
	unsigned int done;		/* completion flag */
} auerchain_chs_t,*pauerchain_chs_t;

/* ...................................................................*/
/* buffer element */
struct  auerbufctl;                     /* forward */
typedef struct
{
        char *bufp;                     /* reference to allocated data buffer */
        unsigned int len;               /* number of characters in data buffer */
	unsigned int retries;		/* for urb retries */
        struct usb_ctrlrequest *dr;	/* for setup data in control messages */
        struct urb * urbp;                   /* USB urb */
        struct auerbufctl *list;        /* pointer to list */
        struct list_head buff_list;     /* reference to next buffer in list */
} auerbuf_t,*pauerbuf_t;

/* buffer list control block */
typedef struct auerbufctl
{
        spinlock_t lock;                /* protection in interrupt */
        struct list_head free_buff_list;/* free buffers */
        struct list_head rec_buff_list; /* buffers with receive data */
} auerbufctl_t,*pauerbufctl_t;

/* ...................................................................*/
/* service context */
struct  auerscon;                       /* forward */
typedef void (*auer_dispatch_t)(struct auerscon*, pauerbuf_t);
typedef void (*auer_disconn_t) (struct auerscon*);
typedef struct auerscon
{
        unsigned int id;                /* protocol service id AUH_xxxx */
        auer_dispatch_t dispatch;       /* dispatch read buffer */
	auer_disconn_t disconnect;	/* disconnect from device, wake up all char readers */
} auerscon_t,*pauerscon_t;

/* ...................................................................*/
/* USB device context */
typedef struct
{
	struct semaphore 	mutex;         	    /* protection in user context */
	char 			name[20];	    /* name of the /dev/usb entry */
	unsigned int		dtindex;	    /* index in the device table */
	struct usb_device *	usbdev;      	    /* USB device handle */
	int			open_count;	    /* count the number of open character channels */
        char 			dev_desc[AUSI_DLEN];/* for storing a textual description */
        unsigned int 		maxControlLength;   /* max. Length of control paket (without header) */
        struct urb * 		inturbp;            /* interrupt urb */
        char *			intbufp;            /* data buffer for interrupt urb */
	unsigned int 		irqsize;	    /* size of interrupt endpoint 1 */
        struct auerchain 	controlchain;  	    /* for chaining of control messages */
	auerbufctl_t 		bufctl;             /* Buffer control for control transfers */
        pauerscon_t 	     	services[AUH_TYPESIZE];/* context pointers for each service */
	unsigned int		version;	    /* Version of the device */
	wait_queue_head_t 	bufferwait;         /* wait for a control buffer */
} auerswald_t,*pauerswald_t;

/* ................................................................... */
/* character device context */
typedef struct
{
	struct semaphore mutex;         /* protection in user context */
	pauerswald_t auerdev;           /* context pointer of assigned device */
        auerbufctl_t bufctl;            /* controls the buffer chain */
        auerscon_t scontext;            /* service context */
	wait_queue_head_t readwait;     /* for synchronous reading */
	struct semaphore readmutex;     /* protection against multiple reads */
	pauerbuf_t readbuf;		/* buffer held for partial reading */
	unsigned int readoffset;	/* current offset in readbuf */
	unsigned int removed;		/* is != 0 if device is removed */
} auerchar_t,*pauerchar_t;


/*-------------------------------------------------------------------*/
/* Forwards */
static void auerswald_ctrlread_complete (struct urb * urb, struct pt_regs *regs);
static void auerswald_removeservice (pauerswald_t cp, pauerscon_t scp);
static struct usb_driver auerswald_driver;


/*-------------------------------------------------------------------*/
/* USB chain helper functions                                        */
/* --------------------------                                        */

/* completion function for chained urbs */
static void auerchain_complete (struct urb * urb, struct pt_regs *regs)
{
	unsigned long flags;
        int result;

        /* get pointer to element and to chain */
        pauerchainelement_t acep = (pauerchainelement_t) urb->context;
        pauerchain_t         acp = acep->chain;

        /* restore original entries in urb */
        urb->context  = acep->context;
        urb->complete = acep->complete;

        dbg ("auerchain_complete called");

        /* call original completion function
           NOTE: this function may lead to more urbs submitted into the chain.
                 (no chain lock at calling complete()!)
                 acp->active != NULL is protecting us against recursion.*/
        urb->complete (urb, regs);

        /* detach element from chain data structure */
	spin_lock_irqsave (&acp->lock, flags);
        if (acp->active != acep) /* paranoia debug check */
	        dbg ("auerchain_complete: completion on non-active element called!");
        else
                acp->active = NULL;

        /* add the used chain element to the list of free elements */
	list_add_tail (&acep->list, &acp->free_list);
        acep = NULL;

        /* is there a new element waiting in the chain? */
        if (!acp->active && !list_empty (&acp->waiting_list)) {
                /* yes: get the entry */
                struct list_head *tmp = acp->waiting_list.next;
                list_del (tmp);
                acep = list_entry (tmp, auerchainelement_t, list);
                acp->active = acep;
        }
        spin_unlock_irqrestore (&acp->lock, flags);

        /* submit the new urb */
        if (acep) {
                urb    = acep->urbp;
                dbg ("auerchain_complete: submitting next urb from chain");
		urb->status = 0;	/* needed! */
		result = usb_submit_urb(urb, GFP_ATOMIC);

                /* check for submit errors */
                if (result) {
                        urb->status = result;
                        dbg("auerchain_complete: usb_submit_urb with error code %d", result);
                        /* and do error handling via *this* completion function (recursive) */
                        auerchain_complete( urb, NULL);
                }
        } else {
                /* simple return without submitting a new urb.
                   The empty chain is detected with acp->active == NULL. */
        };
}


/* submit function for chained urbs
   this function may be called from completion context or from user space!
   early = 1 -> submit in front of chain
*/
static int auerchain_submit_urb_list (pauerchain_t acp, struct urb * urb, int early)
{
        int result;
        unsigned long flags;
        pauerchainelement_t acep = NULL;

        dbg ("auerchain_submit_urb called");

        /* try to get a chain element */
        spin_lock_irqsave (&acp->lock, flags);
        if (!list_empty (&acp->free_list)) {
                /* yes: get the entry */
                struct list_head *tmp = acp->free_list.next;
                list_del (tmp);
                acep = list_entry (tmp, auerchainelement_t, list);
        }
        spin_unlock_irqrestore (&acp->lock, flags);

        /* if no chain element available: return with error */
        if (!acep) {
                return -ENOMEM;
        }

        /* fill in the new chain element values */
        acep->chain    = acp;
        acep->context  = urb->context;
        acep->complete = urb->complete;
        acep->urbp     = urb;
        INIT_LIST_HEAD (&acep->list);

        /* modify urb */
        urb->context   = acep;
        urb->complete  = auerchain_complete;
        urb->status    = -EINPROGRESS;    /* usb_submit_urb does this, too */

        /* add element to chain - or start it immediately */
        spin_lock_irqsave (&acp->lock, flags);
        if (acp->active) {
                /* there is traffic in the chain, simple add element to chain */
		if (early) {
			dbg ("adding new urb to head of chain");
			list_add (&acep->list, &acp->waiting_list);
		} else {
			dbg ("adding new urb to end of chain");
			list_add_tail (&acep->list, &acp->waiting_list);
		}
		acep = NULL;
        } else {
                /* the chain is empty. Prepare restart */
                acp->active = acep;
        }
        /* Spin has to be removed before usb_submit_urb! */
        spin_unlock_irqrestore (&acp->lock, flags);

        /* Submit urb if immediate restart */
        if (acep) {
                dbg("submitting urb immediate");
		urb->status = 0;	/* needed! */
                result = usb_submit_urb(urb, GFP_ATOMIC);
                /* check for submit errors */
                if (result) {
                        urb->status = result;
                        dbg("auerchain_submit_urb: usb_submit_urb with error code %d", result);
                        /* and do error handling via completion function */
                        auerchain_complete( urb, NULL);
                }
        }

        return 0;
}

/* submit function for chained urbs
   this function may be called from completion context or from user space!
*/
static int auerchain_submit_urb (pauerchain_t acp, struct urb * urb)
{
	return auerchain_submit_urb_list (acp, urb, 0);
}

/* cancel an urb which is submitted to the chain
   the result is 0 if the urb is cancelled, or -EINPROGRESS if
   the function is successfully started.
*/
static int auerchain_unlink_urb (pauerchain_t acp, struct urb * urb)
{
	unsigned long flags;
        struct urb * urbp;
        pauerchainelement_t acep;
        struct list_head *tmp;

        dbg ("auerchain_unlink_urb called");

        /* search the chain of waiting elements */
        spin_lock_irqsave (&acp->lock, flags);
        list_for_each (tmp, &acp->waiting_list) {
                acep = list_entry (tmp, auerchainelement_t, list);
                if (acep->urbp == urb) {
                        list_del (tmp);
                        urb->context = acep->context;
                        urb->complete = acep->complete;
                        list_add_tail (&acep->list, &acp->free_list);
                        spin_unlock_irqrestore (&acp->lock, flags);
                        dbg ("unlink waiting urb");
                        urb->status = -ENOENT;
                        urb->complete (urb, NULL);
                        return 0;
                }
        }
        /* not found. */
        spin_unlock_irqrestore (&acp->lock, flags);

        /* get the active urb */
        acep = acp->active;
        if (acep) {
                urbp = acep->urbp;

                /* check if we have to cancel the active urb */
                if (urbp == urb) {
                        /* note that there is a race condition between the check above
                           and the unlink() call because of no lock. This race is harmless,
                           because the usb module will detect the unlink() after completion.
                           We can't use the acp->lock here because the completion function
                           wants to grab it.
			*/
                        dbg ("unlink active urb");
                        return usb_unlink_urb (urbp);
                }
        }

        /* not found anyway
           ... is some kind of success
	*/
        dbg ("urb to unlink not found in chain");
        return 0;
}

/* cancel all urbs which are in the chain.
   this function must not be called from interrupt or completion handler.
*/
static void auerchain_unlink_all (pauerchain_t acp)
{
	unsigned long flags;
        struct urb * urbp;
        pauerchainelement_t acep;

        dbg ("auerchain_unlink_all called");

        /* clear the chain of waiting elements */
        spin_lock_irqsave (&acp->lock, flags);
        while (!list_empty (&acp->waiting_list)) {
                /* get the next entry */
                struct list_head *tmp = acp->waiting_list.next;
                list_del (tmp);
                acep = list_entry (tmp, auerchainelement_t, list);
                urbp = acep->urbp;
                urbp->context = acep->context;
                urbp->complete = acep->complete;
                list_add_tail (&acep->list, &acp->free_list);
                spin_unlock_irqrestore (&acp->lock, flags);
                dbg ("unlink waiting urb");
                urbp->status = -ENOENT;
                urbp->complete (urbp, NULL);
                spin_lock_irqsave (&acp->lock, flags);
        }
        spin_unlock_irqrestore (&acp->lock, flags);

        /* clear the active urb */
        acep = acp->active;
        if (acep) {
                urbp = acep->urbp;
                dbg ("unlink active urb");
                usb_kill_urb (urbp);
        }
}


/* free the chain.
   this function must not be called from interrupt or completion handler.
*/
static void auerchain_free (pauerchain_t acp)
{
	unsigned long flags;
        pauerchainelement_t acep;

        dbg ("auerchain_free called");

        /* first, cancel all pending urbs */
        auerchain_unlink_all (acp);

        /* free the elements */
        spin_lock_irqsave (&acp->lock, flags);
        while (!list_empty (&acp->free_list)) {
                /* get the next entry */
                struct list_head *tmp = acp->free_list.next;
                list_del (tmp);
                spin_unlock_irqrestore (&acp->lock, flags);
		acep = list_entry (tmp, auerchainelement_t, list);
                kfree (acep);
	        spin_lock_irqsave (&acp->lock, flags);
	}
        spin_unlock_irqrestore (&acp->lock, flags);
}


/* Init the chain control structure */
static void auerchain_init (pauerchain_t acp)
{
        /* init the chain data structure */
        acp->active = NULL;
	spin_lock_init (&acp->lock);
        INIT_LIST_HEAD (&acp->waiting_list);
        INIT_LIST_HEAD (&acp->free_list);
}

/* setup a chain.
   It is assumed that there is no concurrency while setting up the chain
   requirement: auerchain_init()
*/
static int auerchain_setup (pauerchain_t acp, unsigned int numElements)
{
        pauerchainelement_t acep;

        dbg ("auerchain_setup called with %d elements", numElements);

        /* fill the list of free elements */
        for (;numElements; numElements--) {
                acep = kzalloc(sizeof(auerchainelement_t), GFP_KERNEL);
                if (!acep)
			goto ac_fail;
                INIT_LIST_HEAD (&acep->list);
                list_add_tail (&acep->list, &acp->free_list);
        }
        return 0;

ac_fail:/* free the elements */
        while (!list_empty (&acp->free_list)) {
                /* get the next entry */
                struct list_head *tmp = acp->free_list.next;
                list_del (tmp);
                acep = list_entry (tmp, auerchainelement_t, list);
                kfree (acep);
        }
        return -ENOMEM;
}


/* completion handler for synchronous chained URBs */
static void auerchain_blocking_completion (struct urb *urb, struct pt_regs *regs)
{
	pauerchain_chs_t pchs = (pauerchain_chs_t)urb->context;
	pchs->done = 1;
	wmb();
	wake_up (&pchs->wqh);
}


/* Starts chained urb and waits for completion or timeout */
static int auerchain_start_wait_urb (pauerchain_t acp, struct urb *urb, int timeout, int* actual_length)
{
	auerchain_chs_t chs;
	int status;

	dbg ("auerchain_start_wait_urb called");
	init_waitqueue_head (&chs.wqh);
	chs.done = 0;

	urb->context = &chs;
	status = auerchain_submit_urb (acp, urb);
	if (status)
		/* something went wrong */
		return status;

	timeout = wait_event_timeout(chs.wqh, chs.done, timeout);

	if (!timeout && !chs.done) {
		if (urb->status != -EINPROGRESS) {	/* No callback?!! */
			dbg ("auerchain_start_wait_urb: raced timeout");
			status = urb->status;
		} else {
			dbg ("auerchain_start_wait_urb: timeout");
			auerchain_unlink_urb (acp, urb);  /* remove urb safely */
			status = -ETIMEDOUT;
		}
	} else
		status = urb->status;

	if (actual_length)
		*actual_length = urb->actual_length;

  	return status;
}


/* auerchain_control_msg - Builds a control urb, sends it off and waits for completion
   acp: pointer to the auerchain
   dev: pointer to the usb device to send the message to
   pipe: endpoint "pipe" to send the message to
   request: USB message request value
   requesttype: USB message request type value
   value: USB message value
   index: USB message index value
   data: pointer to the data to send
   size: length in bytes of the data to send
   timeout: time to wait for the message to complete before timing out (if 0 the wait is forever)

   This function sends a simple control message to a specified endpoint
   and waits for the message to complete, or timeout.

   If successful, it returns the transferred length, otherwise a negative error number.

   Don't use this function from within an interrupt context, like a
   bottom half handler.  If you need an asynchronous message, or need to send
   a message from within interrupt context, use auerchain_submit_urb()
*/
static int auerchain_control_msg (pauerchain_t acp, struct usb_device *dev, unsigned int pipe, __u8 request, __u8 requesttype,
			          __u16 value, __u16 index, void *data, __u16 size, int timeout)
{
	int ret;
	struct usb_ctrlrequest *dr;
	struct urb *urb;
        int length;

        dbg ("auerchain_control_msg");
        dr = kmalloc (sizeof (struct usb_ctrlrequest), GFP_KERNEL);
	if (!dr)
		return -ENOMEM;
	urb = usb_alloc_urb (0, GFP_KERNEL);
	if (!urb) {
        	kfree (dr);
		return -ENOMEM;
        }

	dr->bRequestType = requesttype;
	dr->bRequest = request;
	dr->wValue  = cpu_to_le16 (value);
	dr->wIndex  = cpu_to_le16 (index);
	dr->wLength = cpu_to_le16 (size);

	usb_fill_control_urb (urb, dev, pipe, (unsigned char*)dr, data, size,    /* build urb */
		          auerchain_blocking_completion, NULL);
	ret = auerchain_start_wait_urb (acp, urb, timeout, &length);

	usb_free_urb (urb);
	kfree (dr);

        if (ret < 0)
		return ret;
	else
		return length;
}


/*-------------------------------------------------------------------*/
/* Buffer List helper functions                                      */

/* free a single auerbuf */
static void auerbuf_free (pauerbuf_t bp)
{
	kfree(bp->bufp);
	kfree(bp->dr);
	if (bp->urbp) {
		usb_free_urb(bp->urbp);
	}
	kfree(bp);
}

/* free the buffers from an auerbuf list */
static void auerbuf_free_list (struct list_head *q)
{
        struct list_head *tmp;
	struct list_head *p;
	pauerbuf_t bp;

	dbg ("auerbuf_free_list");
	for (p = q->next; p != q;) {
		bp = list_entry (p, auerbuf_t, buff_list);
		tmp = p->next;
		list_del (p);
		p = tmp;
		auerbuf_free (bp);
	}
}

/* init the members of a list control block */
static void auerbuf_init (pauerbufctl_t bcp)
{
	dbg ("auerbuf_init");
	spin_lock_init (&bcp->lock);
        INIT_LIST_HEAD (&bcp->free_buff_list);
        INIT_LIST_HEAD (&bcp->rec_buff_list);
}

/* free all buffers from an auerbuf chain */
static void auerbuf_free_buffers (pauerbufctl_t bcp)
{
	unsigned long flags;
	dbg ("auerbuf_free_buffers");

        spin_lock_irqsave (&bcp->lock, flags);

	auerbuf_free_list (&bcp->free_buff_list);
	auerbuf_free_list (&bcp->rec_buff_list);

        spin_unlock_irqrestore (&bcp->lock, flags);
}

/* setup a list of buffers */
/* requirement: auerbuf_init() */
static int auerbuf_setup (pauerbufctl_t bcp, unsigned int numElements, unsigned int bufsize)
{
        pauerbuf_t bep = NULL;

        dbg ("auerbuf_setup called with %d elements of %d bytes", numElements, bufsize);

        /* fill the list of free elements */
        for (;numElements; numElements--) {
                bep = kzalloc(sizeof(auerbuf_t), GFP_KERNEL);
                if (!bep)
			goto bl_fail;
                bep->list = bcp;
                INIT_LIST_HEAD (&bep->buff_list);
                bep->bufp = kmalloc (bufsize, GFP_KERNEL);
                if (!bep->bufp)
			goto bl_fail;
                bep->dr = (struct usb_ctrlrequest *) kmalloc (sizeof (struct usb_ctrlrequest), GFP_KERNEL);
                if (!bep->dr)
			goto bl_fail;
                bep->urbp = usb_alloc_urb (0, GFP_KERNEL);
                if (!bep->urbp)
			goto bl_fail;
                list_add_tail (&bep->buff_list, &bcp->free_buff_list);
        }
        return 0;

bl_fail:/* not enough memory. Free allocated elements */
        dbg ("auerbuf_setup: no more memory");
	kfree(bep);
        auerbuf_free_buffers (bcp);
        return -ENOMEM;
}

/* insert a used buffer into the free list */
static void auerbuf_releasebuf( pauerbuf_t bp)
{
        unsigned long flags;
        pauerbufctl_t bcp = bp->list;
	bp->retries = 0;

        dbg ("auerbuf_releasebuf called");
        spin_lock_irqsave (&bcp->lock, flags);
	list_add_tail (&bp->buff_list, &bcp->free_buff_list);
        spin_unlock_irqrestore (&bcp->lock, flags);
}


/*-------------------------------------------------------------------*/
/* Completion handlers */

/* Values of urb->status or results of usb_submit_urb():
0		Initial, OK
-EINPROGRESS	during submission until end
-ENOENT		if urb is unlinked
-ETIMEDOUT	Transfer timed out, NAK
-ENOMEM		Memory Overflow
-ENODEV		Specified USB-device or bus doesn't exist
-ENXIO		URB already queued
-EINVAL		a) Invalid transfer type specified (or not supported)
		b) Invalid interrupt interval (0n256)
-EAGAIN		a) Specified ISO start frame too early
		b) (using ISO-ASAP) Too much scheduled for the future wait some time and try again.
-EFBIG		Too much ISO frames requested (currently uhci900)
-EPIPE		Specified pipe-handle/Endpoint is already stalled
-EMSGSIZE	Endpoint message size is zero, do interface/alternate setting
-EPROTO		a) Bitstuff error
		b) Unknown USB error
-EILSEQ		CRC mismatch
-ENOSR		Buffer error
-EREMOTEIO	Short packet detected
-EXDEV		ISO transfer only partially completed look at individual frame status for details
-EINVAL		ISO madness, if this happens: Log off and go home
-EOVERFLOW	babble
*/

/* check if a status code allows a retry */
static int auerswald_status_retry (int status)
{
	switch (status) {
	case 0:
	case -ETIMEDOUT:
	case -EOVERFLOW:
	case -EAGAIN:
	case -EPIPE:
	case -EPROTO:
	case -EILSEQ:
	case -ENOSR:
	case -EREMOTEIO:
		return 1; /* do a retry */
	}
	return 0;	/* no retry possible */
}

/* Completion of asynchronous write block */
static void auerchar_ctrlwrite_complete (struct urb * urb, struct pt_regs *regs)
{
	pauerbuf_t bp = (pauerbuf_t) urb->context;
	pauerswald_t cp = ((pauerswald_t)((char *)(bp->list)-(unsigned long)(&((pauerswald_t)0)->bufctl)));
	dbg ("auerchar_ctrlwrite_complete called");

	/* reuse the buffer */
	auerbuf_releasebuf (bp);
	/* Wake up all processes waiting for a buffer */
	wake_up (&cp->bufferwait);
}

/* Completion handler for dummy retry packet */
static void auerswald_ctrlread_wretcomplete (struct urb * urb, struct pt_regs *regs)
{
        pauerbuf_t bp = (pauerbuf_t) urb->context;
        pauerswald_t cp;
	int ret;
        dbg ("auerswald_ctrlread_wretcomplete called");
        dbg ("complete with status: %d", urb->status);
	cp = ((pauerswald_t)((char *)(bp->list)-(unsigned long)(&((pauerswald_t)0)->bufctl)));

	/* check if it is possible to advance */
	if (!auerswald_status_retry (urb->status) || !cp->usbdev) {
		/* reuse the buffer */
		err ("control dummy: transmission error %d, can not retry", urb->status);
		auerbuf_releasebuf (bp);
		/* Wake up all processes waiting for a buffer */
		wake_up (&cp->bufferwait);
		return;
	}

	/* fill the control message */
	bp->dr->bRequestType = AUT_RREQ;
	bp->dr->bRequest     = AUV_RBLOCK;
	bp->dr->wLength      = bp->dr->wValue;	/* temporary stored */
	bp->dr->wValue       = cpu_to_le16 (1);	/* Retry Flag */
	/* bp->dr->index    = channel id;          remains */
	usb_fill_control_urb (bp->urbp, cp->usbdev, usb_rcvctrlpipe (cp->usbdev, 0),
                          (unsigned char*)bp->dr, bp->bufp, le16_to_cpu (bp->dr->wLength),
		          auerswald_ctrlread_complete,bp);

	/* submit the control msg as next paket */
	ret = auerchain_submit_urb_list (&cp->controlchain, bp->urbp, 1);
        if (ret) {
        	dbg ("auerswald_ctrlread_complete: nonzero result of auerchain_submit_urb_list %d", ret);
        	bp->urbp->status = ret;
        	auerswald_ctrlread_complete (bp->urbp, NULL);
    	}
}

/* completion handler for receiving of control messages */
static void auerswald_ctrlread_complete (struct urb * urb, struct pt_regs *regs)
{
        unsigned int  serviceid;
        pauerswald_t  cp;
        pauerscon_t   scp;
        pauerbuf_t    bp  = (pauerbuf_t) urb->context;
	int ret;
        dbg ("auerswald_ctrlread_complete called");

	cp = ((pauerswald_t)((char *)(bp->list)-(unsigned long)(&((pauerswald_t)0)->bufctl)));

	/* check if there is valid data in this urb */
        if (urb->status) {
		dbg ("complete with non-zero status: %d", urb->status);
		/* should we do a retry? */
		if (!auerswald_status_retry (urb->status)
		 || !cp->usbdev
		 || (cp->version < AUV_RETRY)
                 || (bp->retries >= AU_RETRIES)) {
			/* reuse the buffer */
			err ("control read: transmission error %d, can not retry", urb->status);
			auerbuf_releasebuf (bp);
			/* Wake up all processes waiting for a buffer */
			wake_up (&cp->bufferwait);
			return;
		}
		bp->retries++;
		dbg ("Retry count = %d", bp->retries);
		/* send a long dummy control-write-message to allow device firmware to react */
		bp->dr->bRequestType = AUT_WREQ;
		bp->dr->bRequest     = AUV_DUMMY;
		bp->dr->wValue       = bp->dr->wLength; /* temporary storage */
		// bp->dr->wIndex    channel ID remains
		bp->dr->wLength      = cpu_to_le16 (32); /* >= 8 bytes */
		usb_fill_control_urb (bp->urbp, cp->usbdev, usb_sndctrlpipe (cp->usbdev, 0),
  			(unsigned char*)bp->dr, bp->bufp, 32,
	   		auerswald_ctrlread_wretcomplete,bp);

		/* submit the control msg as next paket */
       		ret = auerchain_submit_urb_list (&cp->controlchain, bp->urbp, 1);
       		if (ret) {
               		dbg ("auerswald_ctrlread_complete: nonzero result of auerchain_submit_urb_list %d", ret);
               		bp->urbp->status = ret;
               		auerswald_ctrlread_wretcomplete (bp->urbp, regs);
		}
                return;
        }

        /* get the actual bytecount (incl. headerbyte) */
        bp->len = urb->actual_length;
        serviceid = bp->bufp[0] & AUH_TYPEMASK;
        dbg ("Paket with serviceid %d and %d bytes received", serviceid, bp->len);

        /* dispatch the paket */
        scp = cp->services[serviceid];
        if (scp) {
                /* look, Ma, a listener! */
                scp->dispatch (scp, bp);
        }

        /* release the paket */
        auerbuf_releasebuf (bp);
	/* Wake up all processes waiting for a buffer */
	wake_up (&cp->bufferwait);
}

/*-------------------------------------------------------------------*/
/* Handling of Interrupt Endpoint                                    */
/* This interrupt Endpoint is used to inform the host about waiting
   messages from the USB device.
*/
/* int completion handler. */
static void auerswald_int_complete (struct urb * urb, struct pt_regs *regs)
{
        unsigned long flags;
        unsigned  int channelid;
        unsigned  int bytecount;
        int ret;
        pauerbuf_t   bp = NULL;
        pauerswald_t cp = (pauerswald_t) urb->context;

        dbg ("%s called", __FUNCTION__);

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

        /* check if all needed data was received */
	if (urb->actual_length < AU_IRQMINSIZE) {
                dbg ("invalid data length received: %d bytes", urb->actual_length);
		goto exit;
        }

        /* check the command code */
        if (cp->intbufp[0] != AU_IRQCMDID) {
                dbg ("invalid command received: %d", cp->intbufp[0]);
		goto exit;
        }

        /* check the command type */
        if (cp->intbufp[1] != AU_BLOCKRDY) {
                dbg ("invalid command type received: %d", cp->intbufp[1]);
		goto exit;
        }

        /* now extract the information */
        channelid = cp->intbufp[2];
        bytecount = (unsigned char)cp->intbufp[3];
        bytecount |= (unsigned char)cp->intbufp[4] << 8;

        /* check the channel id */
        if (channelid >= AUH_TYPESIZE) {
                dbg ("invalid channel id received: %d", channelid);
		goto exit;
        }

        /* check the byte count */
        if (bytecount > (cp->maxControlLength+AUH_SIZE)) {
                dbg ("invalid byte count received: %d", bytecount);
		goto exit;
        }
        dbg ("Service Channel = %d", channelid);
        dbg ("Byte Count = %d", bytecount);

        /* get a buffer for the next data paket */
        spin_lock_irqsave (&cp->bufctl.lock, flags);
        if (!list_empty (&cp->bufctl.free_buff_list)) {
                /* yes: get the entry */
                struct list_head *tmp = cp->bufctl.free_buff_list.next;
                list_del (tmp);
                bp = list_entry (tmp, auerbuf_t, buff_list);
        }
        spin_unlock_irqrestore (&cp->bufctl.lock, flags);

        /* if no buffer available: skip it */
        if (!bp) {
                dbg ("auerswald_int_complete: no data buffer available");
                /* can we do something more?
		   This is a big problem: if this int packet is ignored, the
		   device will wait forever and not signal any more data.
		   The only real solution is: having enough buffers!
		   Or perhaps temporary disabling the int endpoint?
		*/
		goto exit;
        }

	/* fill the control message */
        bp->dr->bRequestType = AUT_RREQ;
	bp->dr->bRequest     = AUV_RBLOCK;
	bp->dr->wValue       = cpu_to_le16 (0);
	bp->dr->wIndex       = cpu_to_le16 (channelid | AUH_DIRECT | AUH_UNSPLIT);
	bp->dr->wLength      = cpu_to_le16 (bytecount);
	usb_fill_control_urb (bp->urbp, cp->usbdev, usb_rcvctrlpipe (cp->usbdev, 0),
                          (unsigned char*)bp->dr, bp->bufp, bytecount,
		          auerswald_ctrlread_complete,bp);

        /* submit the control msg */
        ret = auerchain_submit_urb (&cp->controlchain, bp->urbp);
        if (ret) {
                dbg ("auerswald_int_complete: nonzero result of auerchain_submit_urb %d", ret);
                bp->urbp->status = ret;
                auerswald_ctrlread_complete( bp->urbp, NULL);
		/* here applies the same problem as above: device locking! */
        }
exit:
	ret = usb_submit_urb (urb, GFP_ATOMIC);
	if (ret)
		err ("%s - usb_submit_urb failed with result %d",
		     __FUNCTION__, ret);
}

/* int memory deallocation
   NOTE: no mutex please!
*/
static void auerswald_int_free (pauerswald_t cp)
{
	if (cp->inturbp) {
		usb_free_urb(cp->inturbp);
		cp->inturbp = NULL;
	}
	kfree(cp->intbufp);
	cp->intbufp = NULL;
}

/* This function is called to activate the interrupt
   endpoint. This function returns 0 if successful or an error code.
   NOTE: no mutex please!
*/
static int auerswald_int_open (pauerswald_t cp)
{
        int ret;
	struct usb_host_endpoint *ep;
	int irqsize;
	dbg ("auerswald_int_open");

	ep = cp->usbdev->ep_in[AU_IRQENDP];
	if (!ep) {
		ret = -EFAULT;
  		goto intoend;
    	}
	irqsize = le16_to_cpu(ep->desc.wMaxPacketSize);
	cp->irqsize = irqsize;

	/* allocate the urb and data buffer */
        if (!cp->inturbp) {
                cp->inturbp = usb_alloc_urb (0, GFP_KERNEL);
                if (!cp->inturbp) {
                        ret = -ENOMEM;
                        goto intoend;
                }
        }
        if (!cp->intbufp) {
                cp->intbufp = kmalloc (irqsize, GFP_KERNEL);
                if (!cp->intbufp) {
                        ret = -ENOMEM;
                        goto intoend;
                }
        }
        /* setup urb */
        usb_fill_int_urb (cp->inturbp, cp->usbdev,
			usb_rcvintpipe (cp->usbdev,AU_IRQENDP), cp->intbufp,
			irqsize, auerswald_int_complete, cp, ep->desc.bInterval);
        /* start the urb */
	cp->inturbp->status = 0;	/* needed! */
	ret = usb_submit_urb (cp->inturbp, GFP_KERNEL);

intoend:
        if (ret < 0) {
                /* activation of interrupt endpoint has failed. Now clean up. */
                dbg ("auerswald_int_open: activation of int endpoint failed");

                /* deallocate memory */
                auerswald_int_free (cp);
        }
        return ret;
}

/* This function is called to deactivate the interrupt
   endpoint. This function returns 0 if successful or an error code.
   NOTE: no mutex please!
*/
static void auerswald_int_release (pauerswald_t cp)
{
        dbg ("auerswald_int_release");

        /* stop the int endpoint */
        if (cp->inturbp)
                usb_kill_urb (cp->inturbp);

        /* deallocate memory */
        auerswald_int_free (cp);
}

/* --------------------------------------------------------------------- */
/* Helper functions                                                      */

/* wake up waiting readers */
static void auerchar_disconnect (pauerscon_t scp)
{
        pauerchar_t ccp = ((pauerchar_t)((char *)(scp)-(unsigned long)(&((pauerchar_t)0)->scontext)));
	dbg ("auerchar_disconnect called");
	ccp->removed = 1;
	wake_up (&ccp->readwait);
}


/* dispatch a read paket to a waiting character device */
static void auerchar_ctrlread_dispatch (pauerscon_t scp, pauerbuf_t bp)
{
	unsigned long flags;
        pauerchar_t ccp;
        pauerbuf_t newbp = NULL;
        char * charp;
        dbg ("auerchar_ctrlread_dispatch called");
        ccp = ((pauerchar_t)((char *)(scp)-(unsigned long)(&((pauerchar_t)0)->scontext)));

        /* get a read buffer from character device context */
        spin_lock_irqsave (&ccp->bufctl.lock, flags);
        if (!list_empty (&ccp->bufctl.free_buff_list)) {
                /* yes: get the entry */
                struct list_head *tmp = ccp->bufctl.free_buff_list.next;
                list_del (tmp);
                newbp = list_entry (tmp, auerbuf_t, buff_list);
        }
        spin_unlock_irqrestore (&ccp->bufctl.lock, flags);

        if (!newbp) {
                dbg ("No read buffer available, discard paket!");
                return;     /* no buffer, no dispatch */
        }

        /* copy information to new buffer element
           (all buffers have the same length) */
        charp = newbp->bufp;
        newbp->bufp = bp->bufp;
        bp->bufp = charp;
        newbp->len = bp->len;

        /* insert new buffer in read list */
        spin_lock_irqsave (&ccp->bufctl.lock, flags);
	list_add_tail (&newbp->buff_list, &ccp->bufctl.rec_buff_list);
        spin_unlock_irqrestore (&ccp->bufctl.lock, flags);
        dbg ("read buffer appended to rec_list");

        /* wake up pending synchronous reads */
	wake_up (&ccp->readwait);
}


/* Delete an auerswald driver context */
static void auerswald_delete( pauerswald_t cp)
{
	dbg( "auerswald_delete");
	if (cp == NULL)
		return;

	/* Wake up all processes waiting for a buffer */
	wake_up (&cp->bufferwait);

	/* Cleaning up */
	auerswald_int_release (cp);
	auerchain_free (&cp->controlchain);
	auerbuf_free_buffers (&cp->bufctl);

	/* release the memory */
	kfree( cp);
}


/* Delete an auerswald character context */
static void auerchar_delete( pauerchar_t ccp)
{
	dbg ("auerchar_delete");
	if (ccp == NULL)
		return;

        /* wake up pending synchronous reads */
	ccp->removed = 1;
	wake_up (&ccp->readwait);

	/* remove the read buffer */
	if (ccp->readbuf) {
		auerbuf_releasebuf (ccp->readbuf);
		ccp->readbuf = NULL;
	}

	/* remove the character buffers */
	auerbuf_free_buffers (&ccp->bufctl);

	/* release the memory */
	kfree( ccp);
}


/* add a new service to the device
   scp->id must be set!
   return: 0 if OK, else error code
*/
static int auerswald_addservice (pauerswald_t cp, pauerscon_t scp)
{
	int ret;

	/* is the device available? */
	if (!cp->usbdev) {
		dbg ("usbdev == NULL");
		return -EIO;	/*no: can not add a service, sorry*/
	}

	/* is the service available? */
	if (cp->services[scp->id]) {
		dbg ("service is busy");
                return -EBUSY;
	}

	/* device is available, service is free */
	cp->services[scp->id] = scp;

	/* register service in device */
	ret = auerchain_control_msg(
		&cp->controlchain,                      /* pointer to control chain */
		cp->usbdev,                             /* pointer to device */
		usb_sndctrlpipe (cp->usbdev, 0),        /* pipe to control endpoint */
		AUV_CHANNELCTL,                         /* USB message request value */
		AUT_WREQ,                               /* USB message request type value */
		0x01,              /* open                 USB message value */
		scp->id,            		        /* USB message index value */
		NULL,                                   /* pointer to the data to send */
		0,                                      /* length in bytes of the data to send */
		HZ * 2);                                /* time to wait for the message to complete before timing out */
	if (ret < 0) {
		dbg ("auerswald_addservice: auerchain_control_msg returned error code %d", ret);
		/* undo above actions */
		cp->services[scp->id] = NULL;
		return ret;
	}

	dbg ("auerswald_addservice: channel open OK");
	return 0;
}


/* remove a service from the the device
   scp->id must be set! */
static void auerswald_removeservice (pauerswald_t cp, pauerscon_t scp)
{
	dbg ("auerswald_removeservice called");

	/* check if we have a service allocated */
	if (scp->id == AUH_UNASSIGNED)
		return;

	/* If there is a device: close the channel */
	if (cp->usbdev) {
		/* Close the service channel inside the device */
		int ret = auerchain_control_msg(
		&cp->controlchain,            		/* pointer to control chain */
		cp->usbdev,         		        /* pointer to device */
		usb_sndctrlpipe (cp->usbdev, 0),	/* pipe to control endpoint */
		AUV_CHANNELCTL,                         /* USB message request value */
		AUT_WREQ,                               /* USB message request type value */
		0x00,              // close             /* USB message value */
		scp->id,            		        /* USB message index value */
		NULL,                                   /* pointer to the data to send */
		0,                                      /* length in bytes of the data to send */
		HZ * 2);                                /* time to wait for the message to complete before timing out */
		if (ret < 0) {
			dbg ("auerswald_removeservice: auerchain_control_msg returned error code %d", ret);
		}
		else {
			dbg ("auerswald_removeservice: channel close OK");
		}
	}

	/* remove the service from the device */
	cp->services[scp->id] = NULL;
	scp->id = AUH_UNASSIGNED;
}


/* --------------------------------------------------------------------- */
/* Char device functions                                                 */

/* Open a new character device */
static int auerchar_open (struct inode *inode, struct file *file)
{
	int dtindex = iminor(inode);
	pauerswald_t cp = NULL;
	pauerchar_t ccp = NULL;
	struct usb_interface *intf;
        int ret;

        /* minor number in range? */
	if (dtindex < 0) {
		return -ENODEV;
        }
	intf = usb_find_interface(&auerswald_driver, dtindex);
	if (!intf) {
		return -ENODEV;
	}

	/* usb device available? */
	cp = usb_get_intfdata (intf);
	if (cp == NULL) {
		return -ENODEV;
	}
	if (down_interruptible (&cp->mutex)) {
		return -ERESTARTSYS;
	}

	/* we have access to the device. Now lets allocate memory */
	ccp = (pauerchar_t) kmalloc(sizeof(auerchar_t), GFP_KERNEL);
	if (ccp == NULL) {
		err ("out of memory");
		ret = -ENOMEM;
		goto ofail;
	}

	/* Initialize device descriptor */
	memset( ccp, 0, sizeof(auerchar_t));
	init_MUTEX( &ccp->mutex);
	init_MUTEX( &ccp->readmutex);
        auerbuf_init (&ccp->bufctl);
        ccp->scontext.id = AUH_UNASSIGNED;
        ccp->scontext.dispatch = auerchar_ctrlread_dispatch;
	ccp->scontext.disconnect = auerchar_disconnect;
	init_waitqueue_head (&ccp->readwait);

	ret = auerbuf_setup (&ccp->bufctl, AU_RBUFFERS, cp->maxControlLength+AUH_SIZE);
       	if (ret) {
		goto ofail;
	}

	cp->open_count++;
	ccp->auerdev = cp;
	dbg("open %s as /dev/%s", cp->dev_desc, cp->name);
	up (&cp->mutex);

	/* file IO stuff */
	file->f_pos = 0;
	file->private_data = ccp;
	return nonseekable_open(inode, file);

	/* Error exit */
ofail:	up (&cp->mutex);
	auerchar_delete (ccp);
	return ret;
}


/* IOCTL functions */
static int auerchar_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
	pauerchar_t ccp = (pauerchar_t) file->private_data;
	int ret = 0;
        audevinfo_t devinfo;
        pauerswald_t cp = NULL;
	unsigned int u;
	unsigned int __user *user_arg = (unsigned int __user *)arg;

        dbg ("ioctl");

	/* get the mutexes */
	if (down_interruptible (&ccp->mutex)) {
		return -ERESTARTSYS;
	}
	cp = ccp->auerdev;
	if (!cp) {
		up (&ccp->mutex);
                return -ENODEV;
	}
	if (down_interruptible (&cp->mutex)) {
		up(&ccp->mutex);
		return -ERESTARTSYS;
	}

	/* Check for removal */
	if (!cp->usbdev) {
		up(&cp->mutex);
		up(&ccp->mutex);
                return -ENODEV;
	}

	switch (cmd) {

	/* return != 0 if Transmitt channel ready to send */
	case IOCTL_AU_TXREADY:
		dbg ("IOCTL_AU_TXREADY");
		u   = ccp->auerdev
		   && (ccp->scontext.id != AUH_UNASSIGNED)
		   && !list_empty (&cp->bufctl.free_buff_list);
	        ret = put_user (u, user_arg);
		break;

	/* return != 0 if connected to a service channel */
	case IOCTL_AU_CONNECT:
		dbg ("IOCTL_AU_CONNECT");
		u = (ccp->scontext.id != AUH_UNASSIGNED);
	        ret = put_user (u, user_arg);
		break;

	/* return != 0 if Receive Data available */
	case IOCTL_AU_RXAVAIL:
		dbg ("IOCTL_AU_RXAVAIL");
		if (ccp->scontext.id == AUH_UNASSIGNED) {
                        ret = -EIO;
                        break;
                }
		u = 0;	/* no data */
		if (ccp->readbuf) {
			int restlen = ccp->readbuf->len - ccp->readoffset;
			if (restlen > 0)
				u = 1;
		}
		if (!u) {
        		if (!list_empty (&ccp->bufctl.rec_buff_list)) {
				u = 1;
			}
		}
	        ret = put_user (u, user_arg);
		break;

	/* return the max. buffer length for the device */
	case IOCTL_AU_BUFLEN:
		dbg ("IOCTL_AU_BUFLEN");
		u = cp->maxControlLength;
	        ret = put_user (u, user_arg);
		break;

	/* requesting a service channel */
        case IOCTL_AU_SERVREQ:
		dbg ("IOCTL_AU_SERVREQ");
                /* requesting a service means: release the previous one first */
		auerswald_removeservice (cp, &ccp->scontext);
		/* get the channel number */
		ret = get_user (u, user_arg);
		if (ret) {
			break;
		}
		if ((u < AUH_FIRSTUSERCH) || (u >= AUH_TYPESIZE)) {
                        ret = -EIO;
                        break;
                }
                dbg ("auerchar service request parameters are ok");
		ccp->scontext.id = u;

		/* request the service now */
		ret = auerswald_addservice (cp, &ccp->scontext);
		if (ret) {
			/* no: revert service entry */
                	ccp->scontext.id = AUH_UNASSIGNED;
		}
		break;

	/* get a string descriptor for the device */
	case IOCTL_AU_DEVINFO:
		dbg ("IOCTL_AU_DEVINFO");
                if (copy_from_user (&devinfo, (void __user *) arg, sizeof (audevinfo_t))) {
        		ret = -EFAULT;
	        	break;
                }
		u = strlen(cp->dev_desc)+1;
		if (u > devinfo.bsize) {
			u = devinfo.bsize;
		}
		ret = copy_to_user(devinfo.buf, cp->dev_desc, u) ? -EFAULT : 0;
		break;

	/* get the max. string descriptor length */
        case IOCTL_AU_SLEN:
		dbg ("IOCTL_AU_SLEN");
		u = AUSI_DLEN;
	        ret = put_user (u, user_arg);
		break;

	default:
		dbg ("IOCTL_AU_UNKNOWN");
		ret = -ENOIOCTLCMD;
		break;
        }
	/* release the mutexes */
	up(&cp->mutex);
	up(&ccp->mutex);
	return ret;
}

/* Read data from the device */
static ssize_t auerchar_read (struct file *file, char __user *buf, size_t count, loff_t * ppos)
{
        unsigned long flags;
	pauerchar_t ccp = (pauerchar_t) file->private_data;
        pauerbuf_t   bp = NULL;
	wait_queue_t wait;

        dbg ("auerchar_read");

	/* Error checking */
	if (!ccp)
		return -EIO;
	if (*ppos)
 		return -ESPIPE;
        if (count == 0)
		return 0;

	/* get the mutex */
	if (down_interruptible (&ccp->mutex))
		return -ERESTARTSYS;

	/* Can we expect to read something? */
	if (ccp->scontext.id == AUH_UNASSIGNED) {
		up (&ccp->mutex);
                return -EIO;
	}

	/* only one reader per device allowed */
	if (down_interruptible (&ccp->readmutex)) {
		up (&ccp->mutex);
		return -ERESTARTSYS;
	}

	/* read data from readbuf, if available */
doreadbuf:
	bp = ccp->readbuf;
	if (bp) {
		/* read the maximum bytes */
		int restlen = bp->len - ccp->readoffset;
		if (restlen < 0)
			restlen = 0;
		if (count > restlen)
			count = restlen;
		if (count) {
			if (copy_to_user (buf, bp->bufp+ccp->readoffset, count)) {
				dbg ("auerswald_read: copy_to_user failed");
				up (&ccp->readmutex);
				up (&ccp->mutex);
				return -EFAULT;
			}
		}
		/* advance the read offset */
		ccp->readoffset += count;
		restlen -= count;
		// reuse the read buffer
		if (restlen <= 0) {
			auerbuf_releasebuf (bp);
			ccp->readbuf = NULL;
		}
		/* return with number of bytes read */
		if (count) {
			up (&ccp->readmutex);
			up (&ccp->mutex);
			return count;
		}
	}

	/* a read buffer is not available. Try to get the next data block. */
doreadlist:
	/* Preparing for sleep */
	init_waitqueue_entry (&wait, current);
	set_current_state (TASK_INTERRUPTIBLE);
	add_wait_queue (&ccp->readwait, &wait);

	bp = NULL;
	spin_lock_irqsave (&ccp->bufctl.lock, flags);
        if (!list_empty (&ccp->bufctl.rec_buff_list)) {
                /* yes: get the entry */
                struct list_head *tmp = ccp->bufctl.rec_buff_list.next;
                list_del (tmp);
                bp = list_entry (tmp, auerbuf_t, buff_list);
        }
        spin_unlock_irqrestore (&ccp->bufctl.lock, flags);

	/* have we got data? */
	if (bp) {
		ccp->readbuf = bp;
		ccp->readoffset = AUH_SIZE; /* for headerbyte */
		set_current_state (TASK_RUNNING);
		remove_wait_queue (&ccp->readwait, &wait);
		goto doreadbuf;		  /* now we can read! */
	}

	/* no data available. Should we wait? */
	if (file->f_flags & O_NONBLOCK) {
                dbg ("No read buffer available, returning -EAGAIN");
		set_current_state (TASK_RUNNING);
		remove_wait_queue (&ccp->readwait, &wait);
		up (&ccp->readmutex);
		up (&ccp->mutex);
		return -EAGAIN;  /* nonblocking, no data available */
        }

	/* yes, we should wait! */
	up (&ccp->mutex); /* allow other operations while we wait */
	schedule();
	remove_wait_queue (&ccp->readwait, &wait);
	if (signal_pending (current)) {
		/* waked up by a signal */
		up (&ccp->readmutex);
		return -ERESTARTSYS;
	}

	/* Anything left to read? */
	if ((ccp->scontext.id == AUH_UNASSIGNED) || ccp->removed) {
		up (&ccp->readmutex);
		return -EIO;
	}

	if (down_interruptible (&ccp->mutex)) {
		up (&ccp->readmutex);
		return -ERESTARTSYS;
	}

	/* try to read the incoming data again */
	goto doreadlist;
}


/* Write a data block into the right service channel of the device */
static ssize_t auerchar_write (struct file *file, const char __user *buf, size_t len, loff_t *ppos)
{
	pauerchar_t ccp = (pauerchar_t) file->private_data;
        pauerswald_t cp = NULL;
        pauerbuf_t bp;
        unsigned long flags;
	int ret;
	wait_queue_t wait;

        dbg ("auerchar_write %zd bytes", len);

	/* Error checking */
	if (!ccp)
		return -EIO;
        if (*ppos)
		return -ESPIPE;
        if (len == 0)
                return 0;

write_again:
	/* get the mutex */
	if (down_interruptible (&ccp->mutex))
		return -ERESTARTSYS;

	/* Can we expect to write something? */
	if (ccp->scontext.id == AUH_UNASSIGNED) {
		up (&ccp->mutex);
                return -EIO;
	}

	cp = ccp->auerdev;
	if (!cp) {
		up (&ccp->mutex);
		return -ERESTARTSYS;
	}
	if (down_interruptible (&cp->mutex)) {
		up (&ccp->mutex);
		return -ERESTARTSYS;
	}
	if (!cp->usbdev) {
		up (&cp->mutex);
		up (&ccp->mutex);
		return -EIO;
	}
	/* Prepare for sleep */
	init_waitqueue_entry (&wait, current);
	set_current_state (TASK_INTERRUPTIBLE);
	add_wait_queue (&cp->bufferwait, &wait);

	/* Try to get a buffer from the device pool.
	   We can't use a buffer from ccp->bufctl because the write
	   command will last beond a release() */
	bp = NULL;
	spin_lock_irqsave (&cp->bufctl.lock, flags);
        if (!list_empty (&cp->bufctl.free_buff_list)) {
                /* yes: get the entry */
                struct list_head *tmp = cp->bufctl.free_buff_list.next;
                list_del (tmp);
                bp = list_entry (tmp, auerbuf_t, buff_list);
        }
        spin_unlock_irqrestore (&cp->bufctl.lock, flags);

	/* are there any buffers left? */
	if (!bp) {
		up (&cp->mutex);
		up (&ccp->mutex);

		/* NONBLOCK: don't wait */
		if (file->f_flags & O_NONBLOCK) {
			set_current_state (TASK_RUNNING);
			remove_wait_queue (&cp->bufferwait, &wait);
			return -EAGAIN;
		}

		/* BLOCKING: wait */
		schedule();
		remove_wait_queue (&cp->bufferwait, &wait);
		if (signal_pending (current)) {
			/* waked up by a signal */
			return -ERESTARTSYS;
		}
		goto write_again;
	} else {
		set_current_state (TASK_RUNNING);
		remove_wait_queue (&cp->bufferwait, &wait);
	}

	/* protect against too big write requests */
	if (len > cp->maxControlLength)
		len = cp->maxControlLength;

	/* Fill the buffer */
	if (copy_from_user ( bp->bufp+AUH_SIZE, buf, len)) {
		dbg ("copy_from_user failed");
		auerbuf_releasebuf (bp);
		/* Wake up all processes waiting for a buffer */
		wake_up (&cp->bufferwait);
		up (&cp->mutex);
		up (&ccp->mutex);
		return -EFAULT;
	}

	/* set the header byte */
        *(bp->bufp) = ccp->scontext.id | AUH_DIRECT | AUH_UNSPLIT;

	/* Set the transfer Parameters */
	bp->len = len+AUH_SIZE;
        bp->dr->bRequestType = AUT_WREQ;
	bp->dr->bRequest     = AUV_WBLOCK;
	bp->dr->wValue       = cpu_to_le16 (0);
	bp->dr->wIndex       = cpu_to_le16 (ccp->scontext.id | AUH_DIRECT | AUH_UNSPLIT);
	bp->dr->wLength      = cpu_to_le16 (len+AUH_SIZE);
	usb_fill_control_urb (bp->urbp, cp->usbdev, usb_sndctrlpipe (cp->usbdev, 0),
                   (unsigned char*)bp->dr, bp->bufp, len+AUH_SIZE,
		    auerchar_ctrlwrite_complete, bp);
	/* up we go */
	ret = auerchain_submit_urb (&cp->controlchain, bp->urbp);
	up (&cp->mutex);
	if (ret) {
		dbg ("auerchar_write: nonzero result of auerchain_submit_urb %d", ret);
		auerbuf_releasebuf (bp);
		/* Wake up all processes waiting for a buffer */
		wake_up (&cp->bufferwait);
		up (&ccp->mutex);
		return -EIO;
	}
	else {
		dbg ("auerchar_write: Write OK");
		up (&ccp->mutex);
		return len;
	}
}


/* Close a character device */
static int auerchar_release (struct inode *inode, struct file *file)
{
	pauerchar_t ccp = (pauerchar_t) file->private_data;
	pauerswald_t cp;
	dbg("release");

	/* get the mutexes */
	if (down_interruptible (&ccp->mutex)) {
		return -ERESTARTSYS;
	}
	cp = ccp->auerdev;
	if (cp) {
		if (down_interruptible (&cp->mutex)) {
			up (&ccp->mutex);
			return -ERESTARTSYS;
		}
		/* remove an open service */
		auerswald_removeservice (cp, &ccp->scontext);
		/* detach from device */
		if ((--cp->open_count <= 0) && (cp->usbdev == NULL)) {
			/* usb device waits for removal */
			up (&cp->mutex);
			auerswald_delete (cp);
		} else {
			up (&cp->mutex);
		}
		cp = NULL;
		ccp->auerdev = NULL;
	}
	up (&ccp->mutex);
	auerchar_delete (ccp);

	return 0;
}


/*----------------------------------------------------------------------*/
/* File operation structure                                             */
static struct file_operations auerswald_fops =
{
	.owner =	THIS_MODULE,
	.llseek =	no_llseek,
	.read =		auerchar_read,
	.write =        auerchar_write,
	.ioctl =	auerchar_ioctl,
	.open =		auerchar_open,
	.release =	auerchar_release,
};

static struct usb_class_driver auerswald_class = {
	.name =		"auer%d",
	.fops =		&auerswald_fops,
	.minor_base =	AUER_MINOR_BASE,
};


/* --------------------------------------------------------------------- */
/* Special USB driver functions                                          */

/* Probe if this driver wants to serve an USB device

   This entry point is called whenever a new device is attached to the bus.
   Then the device driver has to create a new instance of its internal data
   structures for the new device.

   The  dev argument specifies the device context, which contains pointers
   to all USB descriptors. The  interface argument specifies the interface
   number. If a USB driver wants to bind itself to a particular device and
   interface it has to return a pointer. This pointer normally references
   the device driver's context structure.

   Probing normally is done by checking the vendor and product identifications
   or the class and subclass definitions. If they match the interface number
   is compared with the ones supported by the driver. When probing is done
   class based it might be necessary to parse some more USB descriptors because
   the device properties can differ in a wide range.
*/
static int auerswald_probe (struct usb_interface *intf,
			    const struct usb_device_id *id)
{
	struct usb_device *usbdev = interface_to_usbdev(intf);
	pauerswald_t cp = NULL;
	unsigned int u = 0;
	__le16 *pbuf;
	int ret;

	dbg ("probe: vendor id 0x%x, device id 0x%x",
	     le16_to_cpu(usbdev->descriptor.idVendor),
	     le16_to_cpu(usbdev->descriptor.idProduct));

        /* we use only the first -and only- interface */
        if (intf->altsetting->desc.bInterfaceNumber != 0)
		return -ENODEV;

	/* allocate memory for our device and initialize it */
	cp = kmalloc (sizeof(auerswald_t), GFP_KERNEL);
	if (cp == NULL) {
		err ("out of memory");
		goto pfail;
	}

	/* Initialize device descriptor */
	memset (cp, 0, sizeof(auerswald_t));
	init_MUTEX (&cp->mutex);
	cp->usbdev = usbdev;
	auerchain_init (&cp->controlchain);
        auerbuf_init (&cp->bufctl);
	init_waitqueue_head (&cp->bufferwait);

	ret = usb_register_dev(intf, &auerswald_class);
	if (ret) {
		err ("Not able to get a minor for this device.");
		goto pfail;
	}

	/* Give the device a name */
	sprintf (cp->name, "usb/auer%d", intf->minor);

	/* Store the index */
	cp->dtindex = intf->minor;

	/* Get the usb version of the device */
	cp->version = le16_to_cpu(cp->usbdev->descriptor.bcdDevice);
	dbg ("Version is %X", cp->version);

	/* allow some time to settle the device */
	msleep(334);

	/* Try to get a suitable textual description of the device */
	/* Device name:*/
	ret = usb_string( cp->usbdev, AUSI_DEVICE, cp->dev_desc, AUSI_DLEN-1);
	if (ret >= 0) {
		u += ret;
		/* Append Serial Number */
		memcpy(&cp->dev_desc[u], ",Ser# ", 6);
		u += 6;
		ret = usb_string( cp->usbdev, AUSI_SERIALNR, &cp->dev_desc[u], AUSI_DLEN-u-1);
		if (ret >= 0) {
			u += ret;
			/* Append subscriber number */
			memcpy(&cp->dev_desc[u], ", ", 2);
			u += 2;
			ret = usb_string( cp->usbdev, AUSI_MSN, &cp->dev_desc[u], AUSI_DLEN-u-1);
			if (ret >= 0) {
				u += ret;
			}
		}
	}
	cp->dev_desc[u] = '\0';
	info("device is a %s", cp->dev_desc);

        /* get the maximum allowed control transfer length */
        pbuf = (__le16 *) kmalloc (2, GFP_KERNEL);    /* use an allocated buffer because of urb target */
        if (!pbuf) {
		err( "out of memory");
		goto pfail;
	}
        ret = usb_control_msg(cp->usbdev,           /* pointer to device */
                usb_rcvctrlpipe( cp->usbdev, 0 ),   /* pipe to control endpoint */
                AUV_GETINFO,                        /* USB message request value */
                AUT_RREQ,                           /* USB message request type value */
                0,                                  /* USB message value */
                AUDI_MBCTRANS,                      /* USB message index value */
                pbuf,                               /* pointer to the receive buffer */
                2,                                  /* length of the buffer */
                2000);                            /* time to wait for the message to complete before timing out */
        if (ret == 2) {
	        cp->maxControlLength = le16_to_cpup(pbuf);
                kfree(pbuf);
                dbg("setup: max. allowed control transfersize is %d bytes", cp->maxControlLength);
        } else {
                kfree(pbuf);
                err("setup: getting max. allowed control transfer length failed with error %d", ret);
		goto pfail;
        }

	/* allocate a chain for the control messages */
        if (auerchain_setup (&cp->controlchain, AUCH_ELEMENTS)) {
		err ("out of memory");
		goto pfail;
	}

        /* allocate buffers for control messages */
	if (auerbuf_setup (&cp->bufctl, AU_RBUFFERS, cp->maxControlLength+AUH_SIZE)) {
		err ("out of memory");
		goto pfail;
	}

	/* start the interrupt endpoint */
	if (auerswald_int_open (cp)) {
		err ("int endpoint failed");
		goto pfail;
	}

	/* all OK */
	usb_set_intfdata (intf, cp);
	return 0;

	/* Error exit: clean up the memory */
pfail:	auerswald_delete (cp);
	return -EIO;
}


/* Disconnect driver from a served device

   This function is called whenever a device which was served by this driver
   is disconnected.

   The argument  dev specifies the device context and the  driver_context
   returns a pointer to the previously registered  driver_context of the
   probe function. After returning from the disconnect function the USB
   framework completely deallocates all data structures associated with
   this device. So especially the usb_device structure must not be used
   any longer by the usb driver.
*/
static void auerswald_disconnect (struct usb_interface *intf)
{
	pauerswald_t cp = usb_get_intfdata (intf);
	unsigned int u;

	usb_set_intfdata (intf, NULL);
	if (!cp)
		return;

	down (&cp->mutex);
	info ("device /dev/%s now disconnecting", cp->name);

	/* give back our USB minor number */
	usb_deregister_dev(intf, &auerswald_class);

	/* Stop the interrupt endpoint */
	auerswald_int_release (cp);

	/* remove the control chain allocated in auerswald_probe
	   This has the benefit of
	   a) all pending (a)synchronous urbs are unlinked
	   b) all buffers dealing with urbs are reclaimed
	*/
	auerchain_free (&cp->controlchain);

	if (cp->open_count == 0) {
		/* nobody is using this device. So we can clean up now */
		up (&cp->mutex);/* up() is possible here because no other task
				   can open the device (see above). I don't want
				   to kfree() a locked mutex. */
		auerswald_delete (cp);
	} else {
		/* device is used. Remove the pointer to the
		   usb device (it's not valid any more). The last
		   release() will do the clean up */
		cp->usbdev = NULL;
		up (&cp->mutex);
		/* Terminate waiting writers */
		wake_up (&cp->bufferwait);
		/* Inform all waiting readers */
		for ( u = 0; u < AUH_TYPESIZE; u++) {
			pauerscon_t scp = cp->services[u];
			if (scp)
				scp->disconnect( scp);
		}
	}
}

/* Descriptor for the devices which are served by this driver.
   NOTE: this struct is parsed by the usbmanager install scripts.
         Don't change without caution!
*/
static struct usb_device_id auerswald_ids [] = {
	{ USB_DEVICE (ID_AUERSWALD, 0x00C0) },          /* COMpact 2104 USB */
	{ USB_DEVICE (ID_AUERSWALD, 0x00DB) },          /* COMpact 4410/2206 USB */
	{ USB_DEVICE (ID_AUERSWALD, 0x00DC) }, /* COMpact 4406 DSL */
	{ USB_DEVICE (ID_AUERSWALD, 0x00DD) }, /* COMpact 2204 USB */
	{ USB_DEVICE (ID_AUERSWALD, 0x00F1) },          /* Comfort 2000 System Telephone */
	{ USB_DEVICE (ID_AUERSWALD, 0x00F2) },          /* Comfort 1200 System Telephone */
        { }			                        /* Terminating entry */
};

/* Standard module device table */
MODULE_DEVICE_TABLE (usb, auerswald_ids);

/* Standard usb driver struct */
static struct usb_driver auerswald_driver = {
	.name =		"auerswald",
	.probe =	auerswald_probe,
	.disconnect =	auerswald_disconnect,
	.id_table =	auerswald_ids,
};


/* --------------------------------------------------------------------- */
/* Module loading/unloading                                              */

/* Driver initialisation. Called after module loading.
   NOTE: there is no concurrency at _init
*/
static int __init auerswald_init (void)
{
	int result;
	dbg ("init");

	/* register driver at the USB subsystem */
	result = usb_register (&auerswald_driver);
	if (result < 0) {
		err ("driver could not be registered");
		return -1;
	}
	return 0;
}

/* Driver deinit. Called before module removal.
   NOTE: there is no concurrency at _cleanup
*/
static void __exit auerswald_cleanup (void)
{
	dbg ("cleanup");
	usb_deregister (&auerswald_driver);
}

/* --------------------------------------------------------------------- */
/* Linux device driver module description                                */

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

module_init (auerswald_init);
module_exit (auerswald_cleanup);

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