summaryrefslogtreecommitdiffstats
path: root/drivers/usb/serial/mos7720.c
blob: 4554ee49e635d5d4c3d283caf983555630d1b84c (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
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
/*
 * mos7720.c
 *   Controls the Moschip 7720 usb to dual port serial convertor
 *
 * Copyright 2006 Moschip Semiconductor Tech. Ltd.
 *
 * 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, version 2 of the License.
 *
 * Developed by:
 * 	Vijaya Kumar <vijaykumar.gn@gmail.com>
 *	Ajay Kumar <naanuajay@yahoo.com>
 *	Gurudeva <ngurudeva@yahoo.com>
 *
 * Cleaned up from the original by:
 *	Greg Kroah-Hartman <gregkh@suse.de>
 *
 * Originally based on drivers/usb/serial/io_edgeport.c which is:
 *	Copyright (C) 2000 Inside Out Networks, All rights reserved.
 *	Copyright (C) 2001-2002 Greg Kroah-Hartman <greg@kroah.com>
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/serial.h>
#include <linux/serial_reg.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/uaccess.h>
#include <linux/parport.h>

/*
 * Version Information
 */
#define DRIVER_VERSION "2.1"
#define DRIVER_AUTHOR "Aspire Communications pvt Ltd."
#define DRIVER_DESC "Moschip USB Serial Driver"

/* default urb timeout */
#define MOS_WDR_TIMEOUT	(HZ * 5)

#define MOS_MAX_PORT	0x02
#define MOS_WRITE	0x0E
#define MOS_READ	0x0D

/* Interrupt Rotinue Defines	*/
#define SERIAL_IIR_RLS	0x06
#define SERIAL_IIR_RDA	0x04
#define SERIAL_IIR_CTI	0x0c
#define SERIAL_IIR_THR	0x02
#define SERIAL_IIR_MS	0x00

#define NUM_URBS			16	/* URB Count */
#define URB_TRANSFER_BUFFER_SIZE	32	/* URB Size */

/* This structure holds all of the local serial port information */
struct moschip_port {
	__u8	shadowLCR;		/* last LCR value received */
	__u8	shadowMCR;		/* last MCR value received */
	__u8	shadowMSR;		/* last MSR value received */
	char			open;
	struct async_icount	icount;
	struct usb_serial_port	*port;	/* loop back to the owner */
	struct urb		*write_urb_pool[NUM_URBS];
};

static bool debug;

static struct usb_serial_driver moschip7720_2port_driver;

#define USB_VENDOR_ID_MOSCHIP		0x9710
#define MOSCHIP_DEVICE_ID_7720		0x7720
#define MOSCHIP_DEVICE_ID_7715		0x7715

static const struct usb_device_id moschip_port_id_table[] = {
	{ USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7720) },
	{ USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7715) },
	{ } /* terminating entry */
};
MODULE_DEVICE_TABLE(usb, moschip_port_id_table);

#ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT

/* initial values for parport regs */
#define DCR_INIT_VAL       0x0c	/* SLCTIN, nINIT */
#define ECR_INIT_VAL       0x00	/* SPP mode */

struct urbtracker {
	struct mos7715_parport  *mos_parport;
	struct list_head        urblist_entry;
	struct kref             ref_count;
	struct urb              *urb;
};

enum mos7715_pp_modes {
	SPP = 0<<5,
	PS2 = 1<<5,      /* moschip calls this 'NIBBLE' mode */
	PPF = 2<<5,	 /* moschip calls this 'CB-FIFO mode */
};

struct mos7715_parport {
	struct parport          *pp;	       /* back to containing struct */
	struct kref             ref_count;     /* to instance of this struct */
	struct list_head        deferred_urbs; /* list deferred async urbs */
	struct list_head        active_urbs;   /* list async urbs in flight */
	spinlock_t              listlock;      /* protects list access */
	bool                    msg_pending;   /* usb sync call pending */
	struct completion       syncmsg_compl; /* usb sync call completed */
	struct tasklet_struct   urb_tasklet;   /* for sending deferred urbs */
	struct usb_serial       *serial;       /* back to containing struct */
	__u8	                shadowECR;     /* parallel port regs... */
	__u8	                shadowDCR;
	atomic_t                shadowDSR;     /* updated in int-in callback */
};

/* lock guards against dereferencing NULL ptr in parport ops callbacks */
static DEFINE_SPINLOCK(release_lock);

#endif	/* CONFIG_USB_SERIAL_MOS7715_PARPORT */

static const unsigned int dummy; /* for clarity in register access fns */

enum mos_regs {
	THR,	          /* serial port regs */
	RHR,
	IER,
	FCR,
	ISR,
	LCR,
	MCR,
	LSR,
	MSR,
	SPR,
	DLL,
	DLM,
	DPR,              /* parallel port regs */
	DSR,
	DCR,
	ECR,
	SP1_REG,          /* device control regs */
	SP2_REG,          /* serial port 2 (7720 only) */
	PP_REG,
	SP_CONTROL_REG,
};

/*
 * Return the correct value for the Windex field of the setup packet
 * for a control endpoint message.  See the 7715 datasheet.
 */
static inline __u16 get_reg_index(enum mos_regs reg)
{
	static const __u16 mos7715_index_lookup_table[] = {
		0x00,		/* THR */
		0x00,		/* RHR */
		0x01,		/* IER */
		0x02,		/* FCR */
		0x02,		/* ISR */
		0x03,		/* LCR */
		0x04,		/* MCR */
		0x05,		/* LSR */
		0x06,		/* MSR */
		0x07,		/* SPR */
		0x00,		/* DLL */
		0x01,		/* DLM */
		0x00,		/* DPR */
		0x01,		/* DSR */
		0x02,		/* DCR */
		0x0a,		/* ECR */
		0x01,		/* SP1_REG */
		0x02,		/* SP2_REG (7720 only) */
		0x04,		/* PP_REG (7715 only) */
		0x08,		/* SP_CONTROL_REG */
	};
	return mos7715_index_lookup_table[reg];
}

/*
 * Return the correct value for the upper byte of the Wvalue field of
 * the setup packet for a control endpoint message.
 */
static inline __u16 get_reg_value(enum mos_regs reg,
				  unsigned int serial_portnum)
{
	if (reg >= SP1_REG)	      /* control reg */
		return 0x0000;

	else if (reg >= DPR)	      /* parallel port reg (7715 only) */
		return 0x0100;

	else			      /* serial port reg */
		return (serial_portnum + 2) << 8;
}

/*
 * Write data byte to the specified device register.  The data is embedded in
 * the value field of the setup packet. serial_portnum is ignored for registers
 * not specific to a particular serial port.
 */
static int write_mos_reg(struct usb_serial *serial, unsigned int serial_portnum,
			 enum mos_regs reg, __u8 data)
{
	struct usb_device *usbdev = serial->dev;
	unsigned int pipe = usb_sndctrlpipe(usbdev, 0);
	__u8 request = (__u8)0x0e;
	__u8 requesttype = (__u8)0x40;
	__u16 index = get_reg_index(reg);
	__u16 value = get_reg_value(reg, serial_portnum) + data;
	int status = usb_control_msg(usbdev, pipe, request, requesttype, value,
				     index, NULL, 0, MOS_WDR_TIMEOUT);
	if (status < 0)
		dev_err(&usbdev->dev,
			"mos7720: usb_control_msg() failed: %d", status);
	return status;
}

/*
 * Read data byte from the specified device register.  The data returned by the
 * device is embedded in the value field of the setup packet.  serial_portnum is
 * ignored for registers that are not specific to a particular serial port.
 */
static int read_mos_reg(struct usb_serial *serial, unsigned int serial_portnum,
			enum mos_regs reg, __u8 *data)
{
	struct usb_device *usbdev = serial->dev;
	unsigned int pipe = usb_rcvctrlpipe(usbdev, 0);
	__u8 request = (__u8)0x0d;
	__u8 requesttype = (__u8)0xc0;
	__u16 index = get_reg_index(reg);
	__u16 value = get_reg_value(reg, serial_portnum);
	int status = usb_control_msg(usbdev, pipe, request, requesttype, value,
				     index, data, 1, MOS_WDR_TIMEOUT);
	if (status < 0)
		dev_err(&usbdev->dev,
			"mos7720: usb_control_msg() failed: %d", status);
	return status;
}

#ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT

static inline int mos7715_change_mode(struct mos7715_parport *mos_parport,
				      enum mos7715_pp_modes mode)
{
	mos_parport->shadowECR = mode;
	write_mos_reg(mos_parport->serial, dummy, ECR, mos_parport->shadowECR);
	return 0;
}

static void destroy_mos_parport(struct kref *kref)
{
	struct mos7715_parport *mos_parport =
		container_of(kref, struct mos7715_parport, ref_count);

	dbg("%s called", __func__);
	kfree(mos_parport);
}

static void destroy_urbtracker(struct kref *kref)
{
	struct urbtracker *urbtrack =
		container_of(kref, struct urbtracker, ref_count);
	struct mos7715_parport *mos_parport = urbtrack->mos_parport;
	dbg("%s called", __func__);
	usb_free_urb(urbtrack->urb);
	kfree(urbtrack);
	kref_put(&mos_parport->ref_count, destroy_mos_parport);
}

/*
 * This runs as a tasklet when sending an urb in a non-blocking parallel
 * port callback had to be deferred because the disconnect mutex could not be
 * obtained at the time.
 */
static void send_deferred_urbs(unsigned long _mos_parport)
{
	int ret_val;
	unsigned long flags;
	struct mos7715_parport *mos_parport = (void *)_mos_parport;
	struct urbtracker *urbtrack;
	struct list_head *cursor, *next;

	dbg("%s called", __func__);

	/* if release function ran, game over */
	if (unlikely(mos_parport->serial == NULL))
		return;

	/* try again to get the mutex */
	if (!mutex_trylock(&mos_parport->serial->disc_mutex)) {
		dbg("%s: rescheduling tasklet", __func__);
		tasklet_schedule(&mos_parport->urb_tasklet);
		return;
	}

	/* if device disconnected, game over */
	if (unlikely(mos_parport->serial->disconnected)) {
		mutex_unlock(&mos_parport->serial->disc_mutex);
		return;
	}

	spin_lock_irqsave(&mos_parport->listlock, flags);
	if (list_empty(&mos_parport->deferred_urbs)) {
		spin_unlock_irqrestore(&mos_parport->listlock, flags);
		mutex_unlock(&mos_parport->serial->disc_mutex);
		dbg("%s: deferred_urbs list empty", __func__);
		return;
	}

	/* move contents of deferred_urbs list to active_urbs list and submit */
	list_for_each_safe(cursor, next, &mos_parport->deferred_urbs)
		list_move_tail(cursor, &mos_parport->active_urbs);
	list_for_each_entry(urbtrack, &mos_parport->active_urbs,
			    urblist_entry) {
		ret_val = usb_submit_urb(urbtrack->urb, GFP_ATOMIC);
		dbg("%s: urb submitted", __func__);
		if (ret_val) {
			dev_err(&mos_parport->serial->dev->dev,
				"usb_submit_urb() failed: %d", ret_val);
			list_del(&urbtrack->urblist_entry);
			kref_put(&urbtrack->ref_count, destroy_urbtracker);
		}
	}
	spin_unlock_irqrestore(&mos_parport->listlock, flags);
	mutex_unlock(&mos_parport->serial->disc_mutex);
}

/* callback for parallel port control urbs submitted asynchronously */
static void async_complete(struct urb *urb)
{
	struct urbtracker *urbtrack = urb->context;
	int status = urb->status;
	dbg("%s called", __func__);
	if (unlikely(status))
		dbg("%s - nonzero urb status received: %d", __func__, status);

	/* remove the urbtracker from the active_urbs list */
	spin_lock(&urbtrack->mos_parport->listlock);
	list_del(&urbtrack->urblist_entry);
	spin_unlock(&urbtrack->mos_parport->listlock);
	kref_put(&urbtrack->ref_count, destroy_urbtracker);
}

static int write_parport_reg_nonblock(struct mos7715_parport *mos_parport,
				      enum mos_regs reg, __u8 data)
{
	struct urbtracker *urbtrack;
	int ret_val;
	unsigned long flags;
	struct usb_ctrlrequest setup;
	struct usb_serial *serial = mos_parport->serial;
	struct usb_device *usbdev = serial->dev;
	dbg("%s called", __func__);

	/* create and initialize the control urb and containing urbtracker */
	urbtrack = kmalloc(sizeof(struct urbtracker), GFP_ATOMIC);
	if (urbtrack == NULL) {
		dev_err(&usbdev->dev, "out of memory");
		return -ENOMEM;
	}
	kref_get(&mos_parport->ref_count);
	urbtrack->mos_parport = mos_parport;
	urbtrack->urb = usb_alloc_urb(0, GFP_ATOMIC);
	if (urbtrack->urb == NULL) {
		dev_err(&usbdev->dev, "out of urbs");
		kfree(urbtrack);
		return -ENOMEM;
	}
	setup.bRequestType = (__u8)0x40;
	setup.bRequest = (__u8)0x0e;
	setup.wValue = get_reg_value(reg, dummy);
	setup.wIndex = get_reg_index(reg);
	setup.wLength = 0;
	usb_fill_control_urb(urbtrack->urb, usbdev,
			     usb_sndctrlpipe(usbdev, 0),
			     (unsigned char *)&setup,
			     NULL, 0, async_complete, urbtrack);
	kref_init(&urbtrack->ref_count);
	INIT_LIST_HEAD(&urbtrack->urblist_entry);

	/*
	 * get the disconnect mutex, or add tracker to the deferred_urbs list
	 * and schedule a tasklet to try again later
	 */
	if (!mutex_trylock(&serial->disc_mutex)) {
		spin_lock_irqsave(&mos_parport->listlock, flags);
		list_add_tail(&urbtrack->urblist_entry,
			      &mos_parport->deferred_urbs);
		spin_unlock_irqrestore(&mos_parport->listlock, flags);
		tasklet_schedule(&mos_parport->urb_tasklet);
		dbg("tasklet scheduled");
		return 0;
	}

	/* bail if device disconnected */
	if (serial->disconnected) {
		kref_put(&urbtrack->ref_count, destroy_urbtracker);
		mutex_unlock(&serial->disc_mutex);
		return -ENODEV;
	}

	/* add the tracker to the active_urbs list and submit */
	spin_lock_irqsave(&mos_parport->listlock, flags);
	list_add_tail(&urbtrack->urblist_entry, &mos_parport->active_urbs);
	spin_unlock_irqrestore(&mos_parport->listlock, flags);
	ret_val = usb_submit_urb(urbtrack->urb, GFP_ATOMIC);
	mutex_unlock(&serial->disc_mutex);
	if (ret_val) {
		dev_err(&usbdev->dev,
			"%s: submit_urb() failed: %d", __func__, ret_val);
		spin_lock_irqsave(&mos_parport->listlock, flags);
		list_del(&urbtrack->urblist_entry);
		spin_unlock_irqrestore(&mos_parport->listlock, flags);
		kref_put(&urbtrack->ref_count, destroy_urbtracker);
		return ret_val;
	}
	return 0;
}

/*
 * This is the the common top part of all parallel port callback operations that
 * send synchronous messages to the device.  This implements convoluted locking
 * that avoids two scenarios: (1) a port operation is called after usbserial
 * has called our release function, at which point struct mos7715_parport has
 * been destroyed, and (2) the device has been disconnected, but usbserial has
 * not called the release function yet because someone has a serial port open.
 * The shared release_lock prevents the first, and the mutex and disconnected
 * flag maintained by usbserial covers the second.  We also use the msg_pending
 * flag to ensure that all synchronous usb messgage calls have completed before
 * our release function can return.
 */
static int parport_prologue(struct parport *pp)
{
	struct mos7715_parport *mos_parport;

	spin_lock(&release_lock);
	mos_parport = pp->private_data;
	if (unlikely(mos_parport == NULL)) {
		/* release fn called, port struct destroyed */
		spin_unlock(&release_lock);
		return -1;
	}
	mos_parport->msg_pending = true;   /* synch usb call pending */
	INIT_COMPLETION(mos_parport->syncmsg_compl);
	spin_unlock(&release_lock);

	mutex_lock(&mos_parport->serial->disc_mutex);
	if (mos_parport->serial->disconnected) {
		/* device disconnected */
		mutex_unlock(&mos_parport->serial->disc_mutex);
		mos_parport->msg_pending = false;
		complete(&mos_parport->syncmsg_compl);
		return -1;
	}

	return 0;
}

/*
 * This is the the common bottom part of all parallel port functions that send
 * synchronous messages to the device.
 */
static inline void parport_epilogue(struct parport *pp)
{
	struct mos7715_parport *mos_parport = pp->private_data;
	mutex_unlock(&mos_parport->serial->disc_mutex);
	mos_parport->msg_pending = false;
	complete(&mos_parport->syncmsg_compl);
}

static void parport_mos7715_write_data(struct parport *pp, unsigned char d)
{
	struct mos7715_parport *mos_parport = pp->private_data;
	dbg("%s called: %2.2x", __func__, d);
	if (parport_prologue(pp) < 0)
		return;
	mos7715_change_mode(mos_parport, SPP);
	write_mos_reg(mos_parport->serial, dummy, DPR, (__u8)d);
	parport_epilogue(pp);
}

static unsigned char parport_mos7715_read_data(struct parport *pp)
{
	struct mos7715_parport *mos_parport = pp->private_data;
	unsigned char d;
	dbg("%s called", __func__);
	if (parport_prologue(pp) < 0)
		return 0;
	read_mos_reg(mos_parport->serial, dummy, DPR, &d);
	parport_epilogue(pp);
	return d;
}

static void parport_mos7715_write_control(struct parport *pp, unsigned char d)
{
	struct mos7715_parport *mos_parport = pp->private_data;
	__u8 data;
	dbg("%s called: %2.2x", __func__, d);
	if (parport_prologue(pp) < 0)
		return;
	data = ((__u8)d & 0x0f) | (mos_parport->shadowDCR & 0xf0);
	write_mos_reg(mos_parport->serial, dummy, DCR, data);
	mos_parport->shadowDCR = data;
	parport_epilogue(pp);
}

static unsigned char parport_mos7715_read_control(struct parport *pp)
{
	struct mos7715_parport *mos_parport = pp->private_data;
	__u8 dcr;
	dbg("%s called", __func__);
	spin_lock(&release_lock);
	mos_parport = pp->private_data;
	if (unlikely(mos_parport == NULL)) {
		spin_unlock(&release_lock);
		return 0;
	}
	dcr = mos_parport->shadowDCR & 0x0f;
	spin_unlock(&release_lock);
	return dcr;
}

static unsigned char parport_mos7715_frob_control(struct parport *pp,
						  unsigned char mask,
						  unsigned char val)
{
	struct mos7715_parport *mos_parport = pp->private_data;
	__u8 dcr;
	dbg("%s called", __func__);
	mask &= 0x0f;
	val &= 0x0f;
	if (parport_prologue(pp) < 0)
		return 0;
	mos_parport->shadowDCR = (mos_parport->shadowDCR & (~mask)) ^ val;
	write_mos_reg(mos_parport->serial, dummy, DCR, mos_parport->shadowDCR);
	dcr = mos_parport->shadowDCR & 0x0f;
	parport_epilogue(pp);
	return dcr;
}

static unsigned char parport_mos7715_read_status(struct parport *pp)
{
	unsigned char status;
	struct mos7715_parport *mos_parport = pp->private_data;
	dbg("%s called", __func__);
	spin_lock(&release_lock);
	mos_parport = pp->private_data;
	if (unlikely(mos_parport == NULL)) {	/* release called */
		spin_unlock(&release_lock);
		return 0;
	}
	status = atomic_read(&mos_parport->shadowDSR) & 0xf8;
	spin_unlock(&release_lock);
	return status;
}

static void parport_mos7715_enable_irq(struct parport *pp)
{
	dbg("%s called", __func__);
}
static void parport_mos7715_disable_irq(struct parport *pp)
{
	dbg("%s called", __func__);
}

static void parport_mos7715_data_forward(struct parport *pp)
{
	struct mos7715_parport *mos_parport = pp->private_data;
	dbg("%s called", __func__);
	if (parport_prologue(pp) < 0)
		return;
	mos7715_change_mode(mos_parport, PS2);
	mos_parport->shadowDCR &=  ~0x20;
	write_mos_reg(mos_parport->serial, dummy, DCR, mos_parport->shadowDCR);
	parport_epilogue(pp);
}

static void parport_mos7715_data_reverse(struct parport *pp)
{
	struct mos7715_parport *mos_parport = pp->private_data;
	dbg("%s called", __func__);
	if (parport_prologue(pp) < 0)
		return;
	mos7715_change_mode(mos_parport, PS2);
	mos_parport->shadowDCR |= 0x20;
	write_mos_reg(mos_parport->serial, dummy, DCR, mos_parport->shadowDCR);
	parport_epilogue(pp);
}

static void parport_mos7715_init_state(struct pardevice *dev,
				       struct parport_state *s)
{
	dbg("%s called", __func__);
	s->u.pc.ctr = DCR_INIT_VAL;
	s->u.pc.ecr = ECR_INIT_VAL;
}

/* N.B. Parport core code requires that this function not block */
static void parport_mos7715_save_state(struct parport *pp,
				       struct parport_state *s)
{
	struct mos7715_parport *mos_parport;
	dbg("%s called", __func__);
	spin_lock(&release_lock);
	mos_parport = pp->private_data;
	if (unlikely(mos_parport == NULL)) {	/* release called */
		spin_unlock(&release_lock);
		return;
	}
	s->u.pc.ctr = mos_parport->shadowDCR;
	s->u.pc.ecr = mos_parport->shadowECR;
	spin_unlock(&release_lock);
}

/* N.B. Parport core code requires that this function not block */
static void parport_mos7715_restore_state(struct parport *pp,
					  struct parport_state *s)
{
	struct mos7715_parport *mos_parport;
	dbg("%s called", __func__);
	spin_lock(&release_lock);
	mos_parport = pp->private_data;
	if (unlikely(mos_parport == NULL)) {	/* release called */
		spin_unlock(&release_lock);
		return;
	}
	write_parport_reg_nonblock(mos_parport, DCR, mos_parport->shadowDCR);
	write_parport_reg_nonblock(mos_parport, ECR, mos_parport->shadowECR);
	spin_unlock(&release_lock);
}

static size_t parport_mos7715_write_compat(struct parport *pp,
					   const void *buffer,
					   size_t len, int flags)
{
	int retval;
	struct mos7715_parport *mos_parport = pp->private_data;
	int actual_len;
	dbg("%s called: %u chars", __func__, (unsigned int)len);
	if (parport_prologue(pp) < 0)
		return 0;
	mos7715_change_mode(mos_parport, PPF);
	retval = usb_bulk_msg(mos_parport->serial->dev,
			      usb_sndbulkpipe(mos_parport->serial->dev, 2),
			      (void *)buffer, len, &actual_len,
			      MOS_WDR_TIMEOUT);
	parport_epilogue(pp);
	if (retval) {
		dev_err(&mos_parport->serial->dev->dev,
			"mos7720: usb_bulk_msg() failed: %d", retval);
		return 0;
	}
	return actual_len;
}

static struct parport_operations parport_mos7715_ops = {
	.owner =		THIS_MODULE,
	.write_data =		parport_mos7715_write_data,
	.read_data =		parport_mos7715_read_data,

	.write_control =	parport_mos7715_write_control,
	.read_control =		parport_mos7715_read_control,
	.frob_control =		parport_mos7715_frob_control,

	.read_status =		parport_mos7715_read_status,

	.enable_irq =		parport_mos7715_enable_irq,
	.disable_irq =		parport_mos7715_disable_irq,

	.data_forward =		parport_mos7715_data_forward,
	.data_reverse =		parport_mos7715_data_reverse,

	.init_state =		parport_mos7715_init_state,
	.save_state =		parport_mos7715_save_state,
	.restore_state =	parport_mos7715_restore_state,

	.compat_write_data =	parport_mos7715_write_compat,

	.nibble_read_data =	parport_ieee1284_read_nibble,
	.byte_read_data =	parport_ieee1284_read_byte,
};

/*
 * Allocate and initialize parallel port control struct, initialize
 * the parallel port hardware device, and register with the parport subsystem.
 */
static int mos7715_parport_init(struct usb_serial *serial)
{
	struct mos7715_parport *mos_parport;

	/* allocate and initialize parallel port control struct */
	mos_parport = kzalloc(sizeof(struct mos7715_parport), GFP_KERNEL);
	if (mos_parport == NULL) {
		dbg("mos7715_parport_init: kzalloc failed");
		return -ENOMEM;
	}
	mos_parport->msg_pending = false;
	kref_init(&mos_parport->ref_count);
	spin_lock_init(&mos_parport->listlock);
	INIT_LIST_HEAD(&mos_parport->active_urbs);
	INIT_LIST_HEAD(&mos_parport->deferred_urbs);
	usb_set_serial_data(serial, mos_parport); /* hijack private pointer */
	mos_parport->serial = serial;
	tasklet_init(&mos_parport->urb_tasklet, send_deferred_urbs,
		     (unsigned long) mos_parport);
	init_completion(&mos_parport->syncmsg_compl);

	/* cycle parallel port reset bit */
	write_mos_reg(mos_parport->serial, dummy, PP_REG, (__u8)0x80);
	write_mos_reg(mos_parport->serial, dummy, PP_REG, (__u8)0x00);

	/* initialize device registers */
	mos_parport->shadowDCR = DCR_INIT_VAL;
	write_mos_reg(mos_parport->serial, dummy, DCR, mos_parport->shadowDCR);
	mos_parport->shadowECR = ECR_INIT_VAL;
	write_mos_reg(mos_parport->serial, dummy, ECR, mos_parport->shadowECR);

	/* register with parport core */
	mos_parport->pp = parport_register_port(0, PARPORT_IRQ_NONE,
						PARPORT_DMA_NONE,
						&parport_mos7715_ops);
	if (mos_parport->pp == NULL) {
		dev_err(&serial->interface->dev,
			"Could not register parport\n");
		kref_put(&mos_parport->ref_count, destroy_mos_parport);
		return -EIO;
	}
	mos_parport->pp->private_data = mos_parport;
	mos_parport->pp->modes = PARPORT_MODE_COMPAT | PARPORT_MODE_PCSPP;
	mos_parport->pp->dev = &serial->interface->dev;
	parport_announce_port(mos_parport->pp);

	return 0;
}
#endif	/* CONFIG_USB_SERIAL_MOS7715_PARPORT */

/*
 * mos7720_interrupt_callback
 *	this is the callback function for when we have received data on the
 *	interrupt endpoint.
 */
static void mos7720_interrupt_callback(struct urb *urb)
{
	int result;
	int length;
	int status = urb->status;
	__u8 *data;
	__u8 sp1;
	__u8 sp2;

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

	length = urb->actual_length;
	data = urb->transfer_buffer;

	/* Moschip get 4 bytes
	 * Byte 1 IIR Port 1 (port.number is 0)
	 * Byte 2 IIR Port 2 (port.number is 1)
	 * Byte 3 --------------
	 * Byte 4 FIFO status for both */

	/* the above description is inverted
	 * 	oneukum 2007-03-14 */

	if (unlikely(length != 4)) {
		dbg("Wrong data !!!");
		return;
	}

	sp1 = data[3];
	sp2 = data[2];

	if ((sp1 | sp2) & 0x01) {
		/* No Interrupt Pending in both the ports */
		dbg("No Interrupt !!!");
	} else {
		switch (sp1 & 0x0f) {
		case SERIAL_IIR_RLS:
			dbg("Serial Port 1: Receiver status error or address "
			    "bit detected in 9-bit mode\n");
			break;
		case SERIAL_IIR_CTI:
			dbg("Serial Port 1: Receiver time out");
			break;
		case SERIAL_IIR_MS:
			/* dbg("Serial Port 1: Modem status change"); */
			break;
		}

		switch (sp2 & 0x0f) {
		case SERIAL_IIR_RLS:
			dbg("Serial Port 2: Receiver status error or address "
			    "bit detected in 9-bit mode");
			break;
		case SERIAL_IIR_CTI:
			dbg("Serial Port 2: Receiver time out");
			break;
		case SERIAL_IIR_MS:
			/* dbg("Serial Port 2: Modem status change"); */
			break;
		}
	}

exit:
	result = usb_submit_urb(urb, GFP_ATOMIC);
	if (result)
		dev_err(&urb->dev->dev,
			"%s - Error %d submitting control urb\n",
			__func__, result);
}

/*
 * mos7715_interrupt_callback
 *	this is the 7715's callback function for when we have received data on
 *	the interrupt endpoint.
 */
static void mos7715_interrupt_callback(struct urb *urb)
{
	int result;
	int length;
	int status = urb->status;
	__u8 *data;
	__u8 iir;

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

	length = urb->actual_length;
	data = urb->transfer_buffer;

	/* Structure of data from 7715 device:
	 * Byte 1: IIR serial Port
	 * Byte 2: unused
	 * Byte 2: DSR parallel port
	 * Byte 4: FIFO status for both */

	if (unlikely(length != 4)) {
		dbg("Wrong data !!!");
		return;
	}

	iir = data[0];
	if (!(iir & 0x01)) {	/* serial port interrupt pending */
		switch (iir & 0x0f) {
		case SERIAL_IIR_RLS:
			dbg("Serial Port: Receiver status error or address "
			    "bit detected in 9-bit mode\n");
			break;
		case SERIAL_IIR_CTI:
			dbg("Serial Port: Receiver time out");
			break;
		case SERIAL_IIR_MS:
			/* dbg("Serial Port: Modem status change"); */
			break;
		}
	}

#ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT
	{       /* update local copy of DSR reg */
		struct usb_serial_port *port = urb->context;
		struct mos7715_parport *mos_parport = port->serial->private;
		if (unlikely(mos_parport == NULL))
			return;
		atomic_set(&mos_parport->shadowDSR, data[2]);
	}
#endif

exit:
	result = usb_submit_urb(urb, GFP_ATOMIC);
	if (result)
		dev_err(&urb->dev->dev,
			"%s - Error %d submitting control urb\n",
			__func__, result);
}

/*
 * mos7720_bulk_in_callback
 *	this is the callback function for when we have received data on the
 *	bulk in endpoint.
 */
static void mos7720_bulk_in_callback(struct urb *urb)
{
	int retval;
	unsigned char *data ;
	struct usb_serial_port *port;
	struct tty_struct *tty;
	int status = urb->status;

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

	port = urb->context;

	dbg("Entering...%s", __func__);

	data = urb->transfer_buffer;

	tty = tty_port_tty_get(&port->port);
	if (tty && urb->actual_length) {
		tty_insert_flip_string(tty, data, urb->actual_length);
		tty_flip_buffer_push(tty);
	}
	tty_kref_put(tty);

	if (port->read_urb->status != -EINPROGRESS) {
		retval = usb_submit_urb(port->read_urb, GFP_ATOMIC);
		if (retval)
			dbg("usb_submit_urb(read bulk) failed, retval = %d",
			    retval);
	}
}

/*
 * mos7720_bulk_out_data_callback
 *	this is the callback function for when we have finished sending serial
 *	data on the bulk out endpoint.
 */
static void mos7720_bulk_out_data_callback(struct urb *urb)
{
	struct moschip_port *mos7720_port;
	struct tty_struct *tty;
	int status = urb->status;

	if (status) {
		dbg("nonzero write bulk status received:%d", status);
		return;
	}

	mos7720_port = urb->context;
	if (!mos7720_port) {
		dbg("NULL mos7720_port pointer");
		return ;
	}

	tty = tty_port_tty_get(&mos7720_port->port->port);

	if (tty && mos7720_port->open)
		tty_wakeup(tty);
	tty_kref_put(tty);
}

/*
 * mos77xx_probe
 *	this function installs the appropriate read interrupt endpoint callback
 *	depending on whether the device is a 7720 or 7715, thus avoiding costly
 *	run-time checks in the high-frequency callback routine itself.
 */
static int mos77xx_probe(struct usb_serial *serial,
			 const struct usb_device_id *id)
{
	if (id->idProduct == MOSCHIP_DEVICE_ID_7715)
		moschip7720_2port_driver.read_int_callback =
			mos7715_interrupt_callback;
	else
		moschip7720_2port_driver.read_int_callback =
			mos7720_interrupt_callback;

	return 0;
}

static int mos77xx_calc_num_ports(struct usb_serial *serial)
{
	u16 product = le16_to_cpu(serial->dev->descriptor.idProduct);
	if (product == MOSCHIP_DEVICE_ID_7715)
		return 1;

	return 2;
}

static int mos7720_open(struct tty_struct *tty, struct usb_serial_port *port)
{
	struct usb_serial *serial;
	struct urb *urb;
	struct moschip_port *mos7720_port;
	int response;
	int port_number;
	__u8 data;
	int allocated_urbs = 0;
	int j;

	serial = port->serial;

	mos7720_port = usb_get_serial_port_data(port);
	if (mos7720_port == NULL)
		return -ENODEV;

	usb_clear_halt(serial->dev, port->write_urb->pipe);
	usb_clear_halt(serial->dev, port->read_urb->pipe);

	/* Initialising the write urb pool */
	for (j = 0; j < NUM_URBS; ++j) {
		urb = usb_alloc_urb(0, GFP_KERNEL);
		mos7720_port->write_urb_pool[j] = urb;

		if (urb == NULL) {
			dev_err(&port->dev, "No more urbs???\n");
			continue;
		}

		urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
					       GFP_KERNEL);
		if (!urb->transfer_buffer) {
			dev_err(&port->dev,
				"%s-out of memory for urb buffers.\n",
				__func__);
			usb_free_urb(mos7720_port->write_urb_pool[j]);
			mos7720_port->write_urb_pool[j] = NULL;
			continue;
		}
		allocated_urbs++;
	}

	if (!allocated_urbs)
		return -ENOMEM;

	 /* Initialize MCS7720 -- Write Init values to corresponding Registers
	  *
	  * Register Index
	  * 0 : THR/RHR
	  * 1 : IER
	  * 2 : FCR
	  * 3 : LCR
	  * 4 : MCR
	  * 5 : LSR
	  * 6 : MSR
	  * 7 : SPR
	  *
	  * 0x08 : SP1/2 Control Reg
	  */
	port_number = port->number - port->serial->minor;
	read_mos_reg(serial, port_number, LSR, &data);

	dbg("SS::%p LSR:%x", mos7720_port, data);

	dbg("Check:Sending Command ..........");

	write_mos_reg(serial, dummy, SP1_REG, 0x02);
	write_mos_reg(serial, dummy, SP2_REG, 0x02);

	write_mos_reg(serial, port_number, IER, 0x00);
	write_mos_reg(serial, port_number, FCR, 0x00);

	write_mos_reg(serial, port_number, FCR, 0xcf);
	mos7720_port->shadowLCR = 0x03;
	write_mos_reg(serial, port_number, LCR, mos7720_port->shadowLCR);
	mos7720_port->shadowMCR = 0x0b;
	write_mos_reg(serial, port_number, MCR, mos7720_port->shadowMCR);

	write_mos_reg(serial, port_number, SP_CONTROL_REG, 0x00);
	read_mos_reg(serial, dummy, SP_CONTROL_REG, &data);
	data = data | (port->number - port->serial->minor + 1);
	write_mos_reg(serial, dummy, SP_CONTROL_REG, data);
	mos7720_port->shadowLCR = 0x83;
	write_mos_reg(serial, port_number, LCR, mos7720_port->shadowLCR);
	write_mos_reg(serial, port_number, THR, 0x0c);
	write_mos_reg(serial, port_number, IER, 0x00);
	mos7720_port->shadowLCR = 0x03;
	write_mos_reg(serial, port_number, LCR, mos7720_port->shadowLCR);
	write_mos_reg(serial, port_number, IER, 0x0c);

	response = usb_submit_urb(port->read_urb, GFP_KERNEL);
	if (response)
		dev_err(&port->dev, "%s - Error %d submitting read urb\n",
							__func__, response);

	/* initialize our icount structure */
	memset(&(mos7720_port->icount), 0x00, sizeof(mos7720_port->icount));

	/* initialize our port settings */
	mos7720_port->shadowMCR = UART_MCR_OUT2; /* Must set to enable ints! */

	/* send a open port command */
	mos7720_port->open = 1;

	return 0;
}

/*
 * mos7720_chars_in_buffer
 *	this function is called by the tty driver when it wants to know how many
 *	bytes of data we currently have outstanding in the port (data that has
 *	been written, but hasn't made it out the port yet)
 *	If successful, we return the number of bytes left to be written in the
 *	system,
 *	Otherwise we return a negative error number.
 */
static int mos7720_chars_in_buffer(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	int i;
	int chars = 0;
	struct moschip_port *mos7720_port;

	dbg("%s:entering ...........", __func__);

	mos7720_port = usb_get_serial_port_data(port);
	if (mos7720_port == NULL) {
		dbg("%s:leaving ...........", __func__);
		return 0;
	}

	for (i = 0; i < NUM_URBS; ++i) {
		if (mos7720_port->write_urb_pool[i] &&
		    mos7720_port->write_urb_pool[i]->status == -EINPROGRESS)
			chars += URB_TRANSFER_BUFFER_SIZE;
	}
	dbg("%s - returns %d", __func__, chars);
	return chars;
}

static void mos7720_close(struct usb_serial_port *port)
{
	struct usb_serial *serial;
	struct moschip_port *mos7720_port;
	int j;

	dbg("mos7720_close:entering...");

	serial = port->serial;

	mos7720_port = usb_get_serial_port_data(port);
	if (mos7720_port == NULL)
		return;

	for (j = 0; j < NUM_URBS; ++j)
		usb_kill_urb(mos7720_port->write_urb_pool[j]);

	/* Freeing Write URBs */
	for (j = 0; j < NUM_URBS; ++j) {
		if (mos7720_port->write_urb_pool[j]) {
			kfree(mos7720_port->write_urb_pool[j]->transfer_buffer);
			usb_free_urb(mos7720_port->write_urb_pool[j]);
		}
	}

	/* While closing port, shutdown all bulk read, write  *
	 * and interrupt read if they exists, otherwise nop   */
	dbg("Shutdown bulk write");
	usb_kill_urb(port->write_urb);
	dbg("Shutdown bulk read");
	usb_kill_urb(port->read_urb);

	mutex_lock(&serial->disc_mutex);
	/* these commands must not be issued if the device has
	 * been disconnected */
	if (!serial->disconnected) {
		write_mos_reg(serial, port->number - port->serial->minor,
			      MCR, 0x00);
		write_mos_reg(serial, port->number - port->serial->minor,
			      IER, 0x00);
	}
	mutex_unlock(&serial->disc_mutex);
	mos7720_port->open = 0;

	dbg("Leaving %s", __func__);
}

static void mos7720_break(struct tty_struct *tty, int break_state)
{
	struct usb_serial_port *port = tty->driver_data;
	unsigned char data;
	struct usb_serial *serial;
	struct moschip_port *mos7720_port;

	dbg("Entering %s", __func__);

	serial = port->serial;

	mos7720_port = usb_get_serial_port_data(port);
	if (mos7720_port == NULL)
		return;

	if (break_state == -1)
		data = mos7720_port->shadowLCR | UART_LCR_SBC;
	else
		data = mos7720_port->shadowLCR & ~UART_LCR_SBC;

	mos7720_port->shadowLCR  = data;
	write_mos_reg(serial, port->number - port->serial->minor,
		      LCR, mos7720_port->shadowLCR);
}

/*
 * mos7720_write_room
 *	this function is called by the tty driver when it wants to know how many
 *	bytes of data we can accept for a specific port.
 *	If successful, we return the amount of room that we have for this port
 *	Otherwise we return a negative error number.
 */
static int mos7720_write_room(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct moschip_port *mos7720_port;
	int room = 0;
	int i;

	dbg("%s:entering ...........", __func__);

	mos7720_port = usb_get_serial_port_data(port);
	if (mos7720_port == NULL) {
		dbg("%s:leaving ...........", __func__);
		return -ENODEV;
	}

	/* FIXME: Locking */
	for (i = 0; i < NUM_URBS; ++i) {
		if (mos7720_port->write_urb_pool[i] &&
		    mos7720_port->write_urb_pool[i]->status != -EINPROGRESS)
			room += URB_TRANSFER_BUFFER_SIZE;
	}

	dbg("%s - returns %d", __func__, room);
	return room;
}

static int mos7720_write(struct tty_struct *tty, struct usb_serial_port *port,
				 const unsigned char *data, int count)
{
	int status;
	int i;
	int bytes_sent = 0;
	int transfer_size;

	struct moschip_port *mos7720_port;
	struct usb_serial *serial;
	struct urb    *urb;
	const unsigned char *current_position = data;

	dbg("%s:entering ...........", __func__);

	serial = port->serial;

	mos7720_port = usb_get_serial_port_data(port);
	if (mos7720_port == NULL) {
		dbg("mos7720_port is NULL");
		return -ENODEV;
	}

	/* try to find a free urb in the list */
	urb = NULL;

	for (i = 0; i < NUM_URBS; ++i) {
		if (mos7720_port->write_urb_pool[i] &&
		    mos7720_port->write_urb_pool[i]->status != -EINPROGRESS) {
			urb = mos7720_port->write_urb_pool[i];
			dbg("URB:%d", i);
			break;
		}
	}

	if (urb == NULL) {
		dbg("%s - no more free urbs", __func__);
		goto exit;
	}

	if (urb->transfer_buffer == NULL) {
		urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
					       GFP_KERNEL);
		if (urb->transfer_buffer == NULL) {
			dev_err(&port->dev, "%s no more kernel memory...\n",
				__func__);
			goto exit;
		}
	}
	transfer_size = min(count, URB_TRANSFER_BUFFER_SIZE);

	memcpy(urb->transfer_buffer, current_position, transfer_size);
	usb_serial_debug_data(debug, &port->dev, __func__, transfer_size,
			      urb->transfer_buffer);

	/* fill urb with data and submit  */
	usb_fill_bulk_urb(urb, serial->dev,
			  usb_sndbulkpipe(serial->dev,
					port->bulk_out_endpointAddress),
			  urb->transfer_buffer, transfer_size,
			  mos7720_bulk_out_data_callback, mos7720_port);

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

exit:
	return bytes_sent;
}

static void mos7720_throttle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct moschip_port *mos7720_port;
	int status;

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

	mos7720_port = usb_get_serial_port_data(port);

	if (mos7720_port == NULL)
		return;

	if (!mos7720_port->open) {
		dbg("port not opened");
		return;
	}

	dbg("%s: Entering ..........", __func__);

	/* if we are implementing XON/XOFF, send the stop character */
	if (I_IXOFF(tty)) {
		unsigned char stop_char = STOP_CHAR(tty);
		status = mos7720_write(tty, port, &stop_char, 1);
		if (status <= 0)
			return;
	}

	/* if we are implementing RTS/CTS, toggle that line */
	if (tty->termios->c_cflag & CRTSCTS) {
		mos7720_port->shadowMCR &= ~UART_MCR_RTS;
		write_mos_reg(port->serial, port->number - port->serial->minor,
			      MCR, mos7720_port->shadowMCR);
		if (status != 0)
			return;
	}
}

static void mos7720_unthrottle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct moschip_port *mos7720_port = usb_get_serial_port_data(port);
	int status;

	if (mos7720_port == NULL)
		return;

	if (!mos7720_port->open) {
		dbg("%s - port not opened", __func__);
		return;
	}

	dbg("%s: Entering ..........", __func__);

	/* if we are implementing XON/XOFF, send the start character */
	if (I_IXOFF(tty)) {
		unsigned char start_char = START_CHAR(tty);
		status = mos7720_write(tty, port, &start_char, 1);
		if (status <= 0)
			return;
	}

	/* if we are implementing RTS/CTS, toggle that line */
	if (tty->termios->c_cflag & CRTSCTS) {
		mos7720_port->shadowMCR |= UART_MCR_RTS;
		write_mos_reg(port->serial, port->number - port->serial->minor,
			      MCR, mos7720_port->shadowMCR);
		if (status != 0)
			return;
	}
}

/* FIXME: this function does not work */
static int set_higher_rates(struct moschip_port *mos7720_port,
			    unsigned int baud)
{
	struct usb_serial_port *port;
	struct usb_serial *serial;
	int port_number;
	enum mos_regs sp_reg;
	if (mos7720_port == NULL)
		return -EINVAL;

	port = mos7720_port->port;
	serial = port->serial;

	 /***********************************************
	 *      Init Sequence for higher rates
	 ***********************************************/
	dbg("Sending Setting Commands ..........");
	port_number = port->number - port->serial->minor;

	write_mos_reg(serial, port_number, IER, 0x00);
	write_mos_reg(serial, port_number, FCR, 0x00);
	write_mos_reg(serial, port_number, FCR, 0xcf);
	mos7720_port->shadowMCR = 0x0b;
	write_mos_reg(serial, port_number, MCR, mos7720_port->shadowMCR);
	write_mos_reg(serial, dummy, SP_CONTROL_REG, 0x00);

	/***********************************************
	 *              Set for higher rates           *
	 ***********************************************/
	/* writing baud rate verbatum into uart clock field clearly not right */
	if (port_number == 0)
		sp_reg = SP1_REG;
	else
		sp_reg = SP2_REG;
	write_mos_reg(serial, dummy, sp_reg, baud * 0x10);
	write_mos_reg(serial, dummy, SP_CONTROL_REG, 0x03);
	mos7720_port->shadowMCR = 0x2b;
	write_mos_reg(serial, port_number, MCR, mos7720_port->shadowMCR);

	/***********************************************
	 *              Set DLL/DLM
	 ***********************************************/
	mos7720_port->shadowLCR = mos7720_port->shadowLCR | UART_LCR_DLAB;
	write_mos_reg(serial, port_number, LCR, mos7720_port->shadowLCR);
	write_mos_reg(serial, port_number, DLL, 0x01);
	write_mos_reg(serial, port_number, DLM, 0x00);
	mos7720_port->shadowLCR = mos7720_port->shadowLCR & ~UART_LCR_DLAB;
	write_mos_reg(serial, port_number, LCR, mos7720_port->shadowLCR);

	return 0;
}

/* baud rate information */
struct divisor_table_entry {
	__u32  baudrate;
	__u16  divisor;
};

/* Define table of divisors for moschip 7720 hardware	   *
 * These assume a 3.6864MHz crystal, the standard /16, and *
 * MCR.7 = 0.						   */
static struct divisor_table_entry divisor_table[] = {
	{   50,		2304},
	{   110,	1047},	/* 2094.545455 => 230450   => .0217 % over */
	{   134,	857},	/* 1713.011152 => 230398.5 => .00065% under */
	{   150,	768},
	{   300,	384},
	{   600,	192},
	{   1200,	96},
	{   1800,	64},
	{   2400,	48},
	{   4800,	24},
	{   7200,	16},
	{   9600,	12},
	{   19200,	6},
	{   38400,	3},
	{   57600,	2},
	{   115200,	1},
};

/*****************************************************************************
 * calc_baud_rate_divisor
 *	this function calculates the proper baud rate divisor for the specified
 *	baud rate.
 *****************************************************************************/
static int calc_baud_rate_divisor(int baudrate, int *divisor)
{
	int i;
	__u16 custom;
	__u16 round1;
	__u16 round;


	dbg("%s - %d", __func__, baudrate);

	for (i = 0; i < ARRAY_SIZE(divisor_table); i++) {
		if (divisor_table[i].baudrate == baudrate) {
			*divisor = divisor_table[i].divisor;
			return 0;
		}
	}

	/* After trying for all the standard baud rates    *
	 * Try calculating the divisor for this baud rate  */
	if (baudrate > 75 &&  baudrate < 230400) {
		/* get the divisor */
		custom = (__u16)(230400L  / baudrate);

		/* Check for round off */
		round1 = (__u16)(2304000L / baudrate);
		round = (__u16)(round1 - (custom * 10));
		if (round > 4)
			custom++;
		*divisor = custom;

		dbg("Baud %d = %d", baudrate, custom);
		return 0;
	}

	dbg("Baud calculation Failed...");
	return -EINVAL;
}

/*
 * send_cmd_write_baud_rate
 *	this function sends the proper command to change the baud rate of the
 *	specified port.
 */
static int send_cmd_write_baud_rate(struct moschip_port *mos7720_port,
				    int baudrate)
{
	struct usb_serial_port *port;
	struct usb_serial *serial;
	int divisor;
	int status;
	unsigned char number;

	if (mos7720_port == NULL)
		return -1;

	port = mos7720_port->port;
	serial = port->serial;

	dbg("%s: Entering ..........", __func__);

	number = port->number - port->serial->minor;
	dbg("%s - port = %d, baud = %d", __func__, port->number, baudrate);

	/* Calculate the Divisor */
	status = calc_baud_rate_divisor(baudrate, &divisor);
	if (status) {
		dev_err(&port->dev, "%s - bad baud rate\n", __func__);
		return status;
	}

	/* Enable access to divisor latch */
	mos7720_port->shadowLCR = mos7720_port->shadowLCR | UART_LCR_DLAB;
	write_mos_reg(serial, number, LCR, mos7720_port->shadowLCR);

	/* Write the divisor */
	write_mos_reg(serial, number, DLL, (__u8)(divisor & 0xff));
	write_mos_reg(serial, number, DLM, (__u8)((divisor & 0xff00) >> 8));

	/* Disable access to divisor latch */
	mos7720_port->shadowLCR = mos7720_port->shadowLCR & ~UART_LCR_DLAB;
	write_mos_reg(serial, number, LCR, mos7720_port->shadowLCR);

	return status;
}

/*
 * change_port_settings
 *	This routine is called to set the UART on the device to match
 *      the specified new settings.
 */
static void change_port_settings(struct tty_struct *tty,
				 struct moschip_port *mos7720_port,
				 struct ktermios *old_termios)
{
	struct usb_serial_port *port;
	struct usb_serial *serial;
	int baud;
	unsigned cflag;
	unsigned iflag;
	__u8 mask = 0xff;
	__u8 lData;
	__u8 lParity;
	__u8 lStop;
	int status;
	int port_number;

	if (mos7720_port == NULL)
		return ;

	port = mos7720_port->port;
	serial = port->serial;
	port_number = port->number - port->serial->minor;

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

	if (!mos7720_port->open) {
		dbg("%s - port not opened", __func__);
		return;
	}

	dbg("%s: Entering ..........", __func__);

	lData = UART_LCR_WLEN8;
	lStop = 0x00;	/* 1 stop bit */
	lParity = 0x00;	/* No parity */

	cflag = tty->termios->c_cflag;
	iflag = tty->termios->c_iflag;

	/* Change the number of bits */
	switch (cflag & CSIZE) {
	case CS5:
		lData = UART_LCR_WLEN5;
		mask = 0x1f;
		break;

	case CS6:
		lData = UART_LCR_WLEN6;
		mask = 0x3f;
		break;

	case CS7:
		lData = UART_LCR_WLEN7;
		mask = 0x7f;
		break;
	default:
	case CS8:
		lData = UART_LCR_WLEN8;
		break;
	}

	/* Change the Parity bit */
	if (cflag & PARENB) {
		if (cflag & PARODD) {
			lParity = UART_LCR_PARITY;
			dbg("%s - parity = odd", __func__);
		} else {
			lParity = (UART_LCR_EPAR | UART_LCR_PARITY);
			dbg("%s - parity = even", __func__);
		}

	} else {
		dbg("%s - parity = none", __func__);
	}

	if (cflag & CMSPAR)
		lParity = lParity | 0x20;

	/* Change the Stop bit */
	if (cflag & CSTOPB) {
		lStop = UART_LCR_STOP;
		dbg("%s - stop bits = 2", __func__);
	} else {
		lStop = 0x00;
		dbg("%s - stop bits = 1", __func__);
	}

#define LCR_BITS_MASK		0x03	/* Mask for bits/char field */
#define LCR_STOP_MASK		0x04	/* Mask for stop bits field */
#define LCR_PAR_MASK		0x38	/* Mask for parity field */

	/* Update the LCR with the correct value */
	mos7720_port->shadowLCR &=
		~(LCR_BITS_MASK | LCR_STOP_MASK | LCR_PAR_MASK);
	mos7720_port->shadowLCR |= (lData | lParity | lStop);


	/* Disable Interrupts */
	write_mos_reg(serial, port_number, IER, 0x00);
	write_mos_reg(serial, port_number, FCR, 0x00);
	write_mos_reg(serial, port_number, FCR, 0xcf);

	/* Send the updated LCR value to the mos7720 */
	write_mos_reg(serial, port_number, LCR, mos7720_port->shadowLCR);
	mos7720_port->shadowMCR = 0x0b;
	write_mos_reg(serial, port_number, MCR, mos7720_port->shadowMCR);

	/* set up the MCR register and send it to the mos7720 */
	mos7720_port->shadowMCR = UART_MCR_OUT2;
	if (cflag & CBAUD)
		mos7720_port->shadowMCR |= (UART_MCR_DTR | UART_MCR_RTS);

	if (cflag & CRTSCTS) {
		mos7720_port->shadowMCR |= (UART_MCR_XONANY);
		/* To set hardware flow control to the specified *
		 * serial port, in SP1/2_CONTROL_REG             */
		if (port->number)
			write_mos_reg(serial, dummy, SP_CONTROL_REG, 0x01);
		else
			write_mos_reg(serial, dummy, SP_CONTROL_REG, 0x02);

	} else
		mos7720_port->shadowMCR &= ~(UART_MCR_XONANY);

	write_mos_reg(serial, port_number, MCR, mos7720_port->shadowMCR);

	/* Determine divisor based on baud rate */
	baud = tty_get_baud_rate(tty);
	if (!baud) {
		/* pick a default, any default... */
		dbg("Picked default baud...");
		baud = 9600;
	}

	if (baud >= 230400) {
		set_higher_rates(mos7720_port, baud);
		/* Enable Interrupts */
		write_mos_reg(serial, port_number, IER, 0x0c);
		return;
	}

	dbg("%s - baud rate = %d", __func__, baud);
	status = send_cmd_write_baud_rate(mos7720_port, baud);
	/* FIXME: needs to write actual resulting baud back not just
	   blindly do so */
	if (cflag & CBAUD)
		tty_encode_baud_rate(tty, baud, baud);
	/* Enable Interrupts */
	write_mos_reg(serial, port_number, IER, 0x0c);

	if (port->read_urb->status != -EINPROGRESS) {
		status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
		if (status)
			dbg("usb_submit_urb(read bulk) failed, status = %d",
			    status);
	}
}

/*
 * mos7720_set_termios
 *	this function is called by the tty driver when it wants to change the
 *	termios structure.
 */
static void mos7720_set_termios(struct tty_struct *tty,
		struct usb_serial_port *port, struct ktermios *old_termios)
{
	int status;
	unsigned int cflag;
	struct usb_serial *serial;
	struct moschip_port *mos7720_port;

	serial = port->serial;

	mos7720_port = usb_get_serial_port_data(port);

	if (mos7720_port == NULL)
		return;

	if (!mos7720_port->open) {
		dbg("%s - port not opened", __func__);
		return;
	}

	dbg("%s\n", "setting termios - ASPIRE");

	cflag = tty->termios->c_cflag;

	dbg("%s - cflag %08x iflag %08x", __func__,
	    tty->termios->c_cflag,
	    RELEVANT_IFLAG(tty->termios->c_iflag));

	dbg("%s - old cflag %08x old iflag %08x", __func__,
	    old_termios->c_cflag,
	    RELEVANT_IFLAG(old_termios->c_iflag));

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

	/* change the port settings to the new ones specified */
	change_port_settings(tty, mos7720_port, old_termios);

	if (port->read_urb->status != -EINPROGRESS) {
		status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
		if (status)
			dbg("usb_submit_urb(read bulk) failed, status = %d",
			    status);
	}
}

/*
 * get_lsr_info - get line status register info
 *
 * Purpose: Let user call ioctl() to get info when the UART physically
 * 	    is emptied.  On bus types like RS485, the transmitter must
 * 	    release the bus after transmitting. This must be done when
 * 	    the transmit shift register is empty, not be done when the
 * 	    transmit holding register is empty.  This functionality
 * 	    allows an RS485 driver to be written in user space.
 */
static int get_lsr_info(struct tty_struct *tty,
		struct moschip_port *mos7720_port, unsigned int __user *value)
{
	struct usb_serial_port *port = tty->driver_data;
	unsigned int result = 0;
	unsigned char data = 0;
	int port_number = port->number - port->serial->minor;
	int count;

	count = mos7720_chars_in_buffer(tty);
	if (count == 0) {
		read_mos_reg(port->serial, port_number, LSR, &data);
		if ((data & (UART_LSR_TEMT | UART_LSR_THRE))
					== (UART_LSR_TEMT | UART_LSR_THRE)) {
			dbg("%s -- Empty", __func__);
			result = TIOCSER_TEMT;
		}
	}
	if (copy_to_user(value, &result, sizeof(int)))
		return -EFAULT;
	return 0;
}

static int mos7720_tiocmget(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct moschip_port *mos7720_port = usb_get_serial_port_data(port);
	unsigned int result = 0;
	unsigned int mcr ;
	unsigned int msr ;

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

	mcr = mos7720_port->shadowMCR;
	msr = mos7720_port->shadowMSR;

	result = ((mcr & UART_MCR_DTR)  ? TIOCM_DTR : 0)   /* 0x002 */
	  | ((mcr & UART_MCR_RTS)   ? TIOCM_RTS : 0)   /* 0x004 */
	  | ((msr & UART_MSR_CTS)   ? TIOCM_CTS : 0)   /* 0x020 */
	  | ((msr & UART_MSR_DCD)   ? TIOCM_CAR : 0)   /* 0x040 */
	  | ((msr & UART_MSR_RI)    ? TIOCM_RI :  0)   /* 0x080 */
	  | ((msr & UART_MSR_DSR)   ? TIOCM_DSR : 0);  /* 0x100 */

	dbg("%s -- %x", __func__, result);

	return result;
}

static int mos7720_tiocmset(struct tty_struct *tty,
			    unsigned int set, unsigned int clear)
{
	struct usb_serial_port *port = tty->driver_data;
	struct moschip_port *mos7720_port = usb_get_serial_port_data(port);
	unsigned int mcr ;
	dbg("%s - port %d", __func__, port->number);
	dbg("he was at tiocmset");

	mcr = mos7720_port->shadowMCR;

	if (set & TIOCM_RTS)
		mcr |= UART_MCR_RTS;
	if (set & TIOCM_DTR)
		mcr |= UART_MCR_DTR;
	if (set & TIOCM_LOOP)
		mcr |= UART_MCR_LOOP;

	if (clear & TIOCM_RTS)
		mcr &= ~UART_MCR_RTS;
	if (clear & TIOCM_DTR)
		mcr &= ~UART_MCR_DTR;
	if (clear & TIOCM_LOOP)
		mcr &= ~UART_MCR_LOOP;

	mos7720_port->shadowMCR = mcr;
	write_mos_reg(port->serial, port->number - port->serial->minor,
		      MCR, mos7720_port->shadowMCR);

	return 0;
}

static int mos7720_get_icount(struct tty_struct *tty,
				struct serial_icounter_struct *icount)
{
	struct usb_serial_port *port = tty->driver_data;
	struct moschip_port *mos7720_port;
	struct async_icount cnow;

	mos7720_port = usb_get_serial_port_data(port);
	cnow = mos7720_port->icount;

	icount->cts = cnow.cts;
	icount->dsr = cnow.dsr;
	icount->rng = cnow.rng;
	icount->dcd = cnow.dcd;
	icount->rx = cnow.rx;
	icount->tx = cnow.tx;
	icount->frame = cnow.frame;
	icount->overrun = cnow.overrun;
	icount->parity = cnow.parity;
	icount->brk = cnow.brk;
	icount->buf_overrun = cnow.buf_overrun;

	dbg("%s (%d) TIOCGICOUNT RX=%d, TX=%d", __func__,
		port->number, icount->rx, icount->tx);
	return 0;
}

static int set_modem_info(struct moschip_port *mos7720_port, unsigned int cmd,
			  unsigned int __user *value)
{
	unsigned int mcr;
	unsigned int arg;

	struct usb_serial_port *port;

	if (mos7720_port == NULL)
		return -1;

	port = (struct usb_serial_port *)mos7720_port->port;
	mcr = mos7720_port->shadowMCR;

	if (copy_from_user(&arg, value, sizeof(int)))
		return -EFAULT;

	switch (cmd) {
	case TIOCMBIS:
		if (arg & TIOCM_RTS)
			mcr |= UART_MCR_RTS;
		if (arg & TIOCM_DTR)
			mcr |= UART_MCR_RTS;
		if (arg & TIOCM_LOOP)
			mcr |= UART_MCR_LOOP;
		break;

	case TIOCMBIC:
		if (arg & TIOCM_RTS)
			mcr &= ~UART_MCR_RTS;
		if (arg & TIOCM_DTR)
			mcr &= ~UART_MCR_RTS;
		if (arg & TIOCM_LOOP)
			mcr &= ~UART_MCR_LOOP;
		break;

	}

	mos7720_port->shadowMCR = mcr;
	write_mos_reg(port->serial, port->number - port->serial->minor,
		      MCR, mos7720_port->shadowMCR);

	return 0;
}

static int get_serial_info(struct moschip_port *mos7720_port,
			   struct serial_struct __user *retinfo)
{
	struct serial_struct tmp;

	if (!retinfo)
		return -EFAULT;

	memset(&tmp, 0, sizeof(tmp));

	tmp.type		= PORT_16550A;
	tmp.line		= mos7720_port->port->serial->minor;
	tmp.port		= mos7720_port->port->number;
	tmp.irq			= 0;
	tmp.flags		= ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
	tmp.xmit_fifo_size	= NUM_URBS * URB_TRANSFER_BUFFER_SIZE;
	tmp.baud_base		= 9600;
	tmp.close_delay		= 5*HZ;
	tmp.closing_wait	= 30*HZ;

	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
		return -EFAULT;
	return 0;
}

static int mos7720_ioctl(struct tty_struct *tty,
			 unsigned int cmd, unsigned long arg)
{
	struct usb_serial_port *port = tty->driver_data;
	struct moschip_port *mos7720_port;
	struct async_icount cnow;
	struct async_icount cprev;

	mos7720_port = usb_get_serial_port_data(port);
	if (mos7720_port == NULL)
		return -ENODEV;

	dbg("%s - port %d, cmd = 0x%x", __func__, port->number, cmd);

	switch (cmd) {
	case TIOCSERGETLSR:
		dbg("%s (%d) TIOCSERGETLSR", __func__,  port->number);
		return get_lsr_info(tty, mos7720_port,
					(unsigned int __user *)arg);

	/* FIXME: These should be using the mode methods */
	case TIOCMBIS:
	case TIOCMBIC:
		dbg("%s (%d) TIOCMSET/TIOCMBIC/TIOCMSET",
					__func__, port->number);
		return set_modem_info(mos7720_port, cmd,
				      (unsigned int __user *)arg);

	case TIOCGSERIAL:
		dbg("%s (%d) TIOCGSERIAL", __func__,  port->number);
		return get_serial_info(mos7720_port,
				       (struct serial_struct __user *)arg);

	case TIOCMIWAIT:
		dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);
		cprev = mos7720_port->icount;
		while (1) {
			if (signal_pending(current))
				return -ERESTARTSYS;
			cnow = mos7720_port->icount;
			if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
			    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
				return -EIO; /* no change => error */
			if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
			    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
			    ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
			    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
				return 0;
			}
			cprev = cnow;
		}
		/* NOTREACHED */
		break;
	}

	return -ENOIOCTLCMD;
}

static int mos7720_startup(struct usb_serial *serial)
{
	struct moschip_port *mos7720_port;
	struct usb_device *dev;
	int i;
	char data;
	u16 product;
	int ret_val;

	dbg("%s: Entering ..........", __func__);

	if (!serial) {
		dbg("Invalid Handler");
		return -ENODEV;
	}

	product = le16_to_cpu(serial->dev->descriptor.idProduct);
	dev = serial->dev;

	/*
	 * The 7715 uses the first bulk in/out endpoint pair for the parallel
	 * port, and the second for the serial port.  Because the usbserial core
	 * assumes both pairs are serial ports, we must engage in a bit of
	 * subterfuge and swap the pointers for ports 0 and 1 in order to make
	 * port 0 point to the serial port.  However, both moschip devices use a
	 * single interrupt-in endpoint for both ports (as mentioned a little
	 * further down), and this endpoint was assigned to port 0.  So after
	 * the swap, we must copy the interrupt endpoint elements from port 1
	 * (as newly assigned) to port 0, and null out port 1 pointers.
	 */
	if (product == MOSCHIP_DEVICE_ID_7715) {
		struct usb_serial_port *tmp = serial->port[0];
		serial->port[0] = serial->port[1];
		serial->port[1] = tmp;
		serial->port[0]->interrupt_in_urb = tmp->interrupt_in_urb;
		serial->port[0]->interrupt_in_buffer = tmp->interrupt_in_buffer;
		serial->port[0]->interrupt_in_endpointAddress =
			tmp->interrupt_in_endpointAddress;
		serial->port[1]->interrupt_in_urb = NULL;
		serial->port[1]->interrupt_in_buffer = NULL;
	}


	/* set up serial port private structures */
	for (i = 0; i < serial->num_ports; ++i) {
		mos7720_port = kzalloc(sizeof(struct moschip_port), GFP_KERNEL);
		if (mos7720_port == NULL) {
			dev_err(&dev->dev, "%s - Out of memory\n", __func__);
			return -ENOMEM;
		}

		/* Initialize all port interrupt end point to port 0 int
		 * endpoint.  Our device has only one interrupt endpoint
		 * common to all ports */
		serial->port[i]->interrupt_in_endpointAddress =
				serial->port[0]->interrupt_in_endpointAddress;

		mos7720_port->port = serial->port[i];
		usb_set_serial_port_data(serial->port[i], mos7720_port);

		dbg("port number is %d", serial->port[i]->number);
		dbg("serial number is %d", serial->minor);
	}


	/* setting configuration feature to one */
	usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
			(__u8)0x03, 0x00, 0x01, 0x00, NULL, 0x00, 5*HZ);

	/* start the interrupt urb */
	ret_val = usb_submit_urb(serial->port[0]->interrupt_in_urb, GFP_KERNEL);
	if (ret_val)
		dev_err(&dev->dev,
			"%s - Error %d submitting control urb\n",
			__func__, ret_val);

#ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT
	if (product == MOSCHIP_DEVICE_ID_7715) {
		ret_val = mos7715_parport_init(serial);
		if (ret_val < 0)
			return ret_val;
	}
#endif
	/* LSR For Port 1 */
	read_mos_reg(serial, 0, LSR, &data);
	dbg("LSR:%x", data);

	return 0;
}

static void mos7720_release(struct usb_serial *serial)
{
	int i;

#ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT
	/* close the parallel port */

	if (le16_to_cpu(serial->dev->descriptor.idProduct)
	    == MOSCHIP_DEVICE_ID_7715) {
		struct urbtracker *urbtrack;
		unsigned long flags;
		struct mos7715_parport *mos_parport =
			usb_get_serial_data(serial);

		/* prevent NULL ptr dereference in port callbacks */
		spin_lock(&release_lock);
		mos_parport->pp->private_data = NULL;
		spin_unlock(&release_lock);

		/* wait for synchronous usb calls to return */
		if (mos_parport->msg_pending)
			wait_for_completion_timeout(&mos_parport->syncmsg_compl,
						    MOS_WDR_TIMEOUT);

		parport_remove_port(mos_parport->pp);
		usb_set_serial_data(serial, NULL);
		mos_parport->serial = NULL;

		/* if tasklet currently scheduled, wait for it to complete */
		tasklet_kill(&mos_parport->urb_tasklet);

		/* unlink any urbs sent by the tasklet  */
		spin_lock_irqsave(&mos_parport->listlock, flags);
		list_for_each_entry(urbtrack,
				    &mos_parport->active_urbs,
				    urblist_entry)
			usb_unlink_urb(urbtrack->urb);
		spin_unlock_irqrestore(&mos_parport->listlock, flags);

		kref_put(&mos_parport->ref_count, destroy_mos_parport);
	}
#endif
	/* free private structure allocated for serial port */
	for (i = 0; i < serial->num_ports; ++i)
		kfree(usb_get_serial_port_data(serial->port[i]));
}

static struct usb_driver usb_driver = {
	.name =		"moschip7720",
	.probe =	usb_serial_probe,
	.disconnect =	usb_serial_disconnect,
	.id_table =	moschip_port_id_table,
	.no_dynamic_id =	1,
};

static struct usb_serial_driver moschip7720_2port_driver = {
	.driver = {
		.owner =	THIS_MODULE,
		.name =		"moschip7720",
	},
	.description		= "Moschip 2 port adapter",
	.usb_driver		= &usb_driver,
	.id_table		= moschip_port_id_table,
	.calc_num_ports		= mos77xx_calc_num_ports,
	.open			= mos7720_open,
	.close			= mos7720_close,
	.throttle		= mos7720_throttle,
	.unthrottle		= mos7720_unthrottle,
	.probe			= mos77xx_probe,
	.attach			= mos7720_startup,
	.release		= mos7720_release,
	.ioctl			= mos7720_ioctl,
	.tiocmget		= mos7720_tiocmget,
	.tiocmset		= mos7720_tiocmset,
	.get_icount		= mos7720_get_icount,
	.set_termios		= mos7720_set_termios,
	.write			= mos7720_write,
	.write_room		= mos7720_write_room,
	.chars_in_buffer	= mos7720_chars_in_buffer,
	.break_ctl		= mos7720_break,
	.read_bulk_callback	= mos7720_bulk_in_callback,
	.read_int_callback	= NULL  /* dynamically assigned in probe() */
};

static int __init moschip7720_init(void)
{
	int retval;

	dbg("%s: Entering ..........", __func__);

	/* Register with the usb serial */
	retval = usb_serial_register(&moschip7720_2port_driver);
	if (retval)
		goto failed_port_device_register;

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

	/* Register with the usb */
	retval = usb_register(&usb_driver);
	if (retval)
		goto failed_usb_register;

	return 0;

failed_usb_register:
	usb_serial_deregister(&moschip7720_2port_driver);

failed_port_device_register:
	return retval;
}

static void __exit moschip7720_exit(void)
{
	usb_deregister(&usb_driver);
	usb_serial_deregister(&moschip7720_2port_driver);
}

module_init(moschip7720_init);
module_exit(moschip7720_exit);

/* Module information */
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");
OpenPOWER on IntegriCloud