Linux Audio

Check our new training course

Embedded Linux Audio

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

Bootlin logo

Elixir Cross Referencer

Loading...
   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
// SPDX-License-Identifier: GPL-2.0
/* sunzilog.c: Zilog serial driver for Sparc systems.
 *
 * Driver for Zilog serial chips found on Sun workstations and
 * servers.  This driver could actually be made more generic.
 *
 * This is based on the old drivers/sbus/char/zs.c code.  A lot
 * of code has been simply moved over directly from there but
 * much has been rewritten.  Credits therefore go out to Eddie
 * C. Dost, Pete Zaitcev, Ted Ts'o and Alex Buell for their
 * work there.
 *
 * Copyright (C) 2002, 2006, 2007 David S. Miller (davem@davemloft.net)
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/circ_buf.h>
#include <linux/serial.h>
#include <linux/sysrq.h>
#include <linux/console.h>
#include <linux/spinlock.h>
#ifdef CONFIG_SERIO
#include <linux/serio.h>
#endif
#include <linux/init.h>
#include <linux/of_device.h>

#include <linux/io.h>
#include <asm/irq.h>
#include <asm/prom.h>
#include <asm/setup.h>

#include <linux/serial_core.h>
#include <linux/sunserialcore.h>

#include "sunzilog.h"

/* On 32-bit sparcs we need to delay after register accesses
 * to accommodate sun4 systems, but we do not need to flush writes.
 * On 64-bit sparc we only need to flush single writes to ensure
 * completion.
 */
#ifndef CONFIG_SPARC64
#define ZSDELAY()		udelay(5)
#define ZSDELAY_LONG()		udelay(20)
#define ZS_WSYNC(channel)	do { } while (0)
#else
#define ZSDELAY()
#define ZSDELAY_LONG()
#define ZS_WSYNC(__channel) \
	readb(&((__channel)->control))
#endif

#define ZS_CLOCK		4915200 /* Zilog input clock rate. */
#define ZS_CLOCK_DIVISOR	16      /* Divisor this driver uses. */

/*
 * We wrap our port structure around the generic uart_port.
 */
struct uart_sunzilog_port {
	struct uart_port		port;

	/* IRQ servicing chain.  */
	struct uart_sunzilog_port	*next;

	/* Current values of Zilog write registers.  */
	unsigned char			curregs[NUM_ZSREGS];

	unsigned int			flags;
#define SUNZILOG_FLAG_CONS_KEYB		0x00000001
#define SUNZILOG_FLAG_CONS_MOUSE	0x00000002
#define SUNZILOG_FLAG_IS_CONS		0x00000004
#define SUNZILOG_FLAG_IS_KGDB		0x00000008
#define SUNZILOG_FLAG_MODEM_STATUS	0x00000010
#define SUNZILOG_FLAG_IS_CHANNEL_A	0x00000020
#define SUNZILOG_FLAG_REGS_HELD		0x00000040
#define SUNZILOG_FLAG_TX_STOPPED	0x00000080
#define SUNZILOG_FLAG_TX_ACTIVE		0x00000100
#define SUNZILOG_FLAG_ESCC		0x00000200
#define SUNZILOG_FLAG_ISR_HANDLER	0x00000400

	unsigned int cflag;

	unsigned char			parity_mask;
	unsigned char			prev_status;

#ifdef CONFIG_SERIO
	struct serio			serio;
	int				serio_open;
#endif
};

static void sunzilog_putchar(struct uart_port *port, unsigned char ch);

#define ZILOG_CHANNEL_FROM_PORT(PORT)	((struct zilog_channel __iomem *)((PORT)->membase))
#define UART_ZILOG(PORT)		((struct uart_sunzilog_port *)(PORT))

#define ZS_IS_KEYB(UP)	((UP)->flags & SUNZILOG_FLAG_CONS_KEYB)
#define ZS_IS_MOUSE(UP)	((UP)->flags & SUNZILOG_FLAG_CONS_MOUSE)
#define ZS_IS_CONS(UP)	((UP)->flags & SUNZILOG_FLAG_IS_CONS)
#define ZS_IS_KGDB(UP)	((UP)->flags & SUNZILOG_FLAG_IS_KGDB)
#define ZS_WANTS_MODEM_STATUS(UP)	((UP)->flags & SUNZILOG_FLAG_MODEM_STATUS)
#define ZS_IS_CHANNEL_A(UP)	((UP)->flags & SUNZILOG_FLAG_IS_CHANNEL_A)
#define ZS_REGS_HELD(UP)	((UP)->flags & SUNZILOG_FLAG_REGS_HELD)
#define ZS_TX_STOPPED(UP)	((UP)->flags & SUNZILOG_FLAG_TX_STOPPED)
#define ZS_TX_ACTIVE(UP)	((UP)->flags & SUNZILOG_FLAG_TX_ACTIVE)

/* Reading and writing Zilog8530 registers.  The delays are to make this
 * driver work on the Sun4 which needs a settling delay after each chip
 * register access, other machines handle this in hardware via auxiliary
 * flip-flops which implement the settle time we do in software.
 *
 * The port lock must be held and local IRQs must be disabled
 * when {read,write}_zsreg is invoked.
 */
static unsigned char read_zsreg(struct zilog_channel __iomem *channel,
				unsigned char reg)
{
	unsigned char retval;

	writeb(reg, &channel->control);
	ZSDELAY();
	retval = readb(&channel->control);
	ZSDELAY();

	return retval;
}

static void write_zsreg(struct zilog_channel __iomem *channel,
			unsigned char reg, unsigned char value)
{
	writeb(reg, &channel->control);
	ZSDELAY();
	writeb(value, &channel->control);
	ZSDELAY();
}

static void sunzilog_clear_fifo(struct zilog_channel __iomem *channel)
{
	int i;

	for (i = 0; i < 32; i++) {
		unsigned char regval;

		regval = readb(&channel->control);
		ZSDELAY();
		if (regval & Rx_CH_AV)
			break;

		regval = read_zsreg(channel, R1);
		readb(&channel->data);
		ZSDELAY();

		if (regval & (PAR_ERR | Rx_OVR | CRC_ERR)) {
			writeb(ERR_RES, &channel->control);
			ZSDELAY();
			ZS_WSYNC(channel);
		}
	}
}

/* This function must only be called when the TX is not busy.  The UART
 * port lock must be held and local interrupts disabled.
 */
static int __load_zsregs(struct zilog_channel __iomem *channel, unsigned char *regs)
{
	int i;
	int escc;
	unsigned char r15;

	/* Let pending transmits finish.  */
	for (i = 0; i < 1000; i++) {
		unsigned char stat = read_zsreg(channel, R1);
		if (stat & ALL_SNT)
			break;
		udelay(100);
	}

	writeb(ERR_RES, &channel->control);
	ZSDELAY();
	ZS_WSYNC(channel);

	sunzilog_clear_fifo(channel);

	/* Disable all interrupts.  */
	write_zsreg(channel, R1,
		    regs[R1] & ~(RxINT_MASK | TxINT_ENAB | EXT_INT_ENAB));

	/* Set parity, sync config, stop bits, and clock divisor.  */
	write_zsreg(channel, R4, regs[R4]);

	/* Set misc. TX/RX control bits.  */
	write_zsreg(channel, R10, regs[R10]);

	/* Set TX/RX controls sans the enable bits.  */
	write_zsreg(channel, R3, regs[R3] & ~RxENAB);
	write_zsreg(channel, R5, regs[R5] & ~TxENAB);

	/* Synchronous mode config.  */
	write_zsreg(channel, R6, regs[R6]);
	write_zsreg(channel, R7, regs[R7]);

	/* Don't mess with the interrupt vector (R2, unused by us) and
	 * master interrupt control (R9).  We make sure this is setup
	 * properly at probe time then never touch it again.
	 */

	/* Disable baud generator.  */
	write_zsreg(channel, R14, regs[R14] & ~BRENAB);

	/* Clock mode control.  */
	write_zsreg(channel, R11, regs[R11]);

	/* Lower and upper byte of baud rate generator divisor.  */
	write_zsreg(channel, R12, regs[R12]);
	write_zsreg(channel, R13, regs[R13]);
	
	/* Now rewrite R14, with BRENAB (if set).  */
	write_zsreg(channel, R14, regs[R14]);

	/* External status interrupt control.  */
	write_zsreg(channel, R15, (regs[R15] | WR7pEN) & ~FIFOEN);

	/* ESCC Extension Register */
	r15 = read_zsreg(channel, R15);
	if (r15 & 0x01)	{
		write_zsreg(channel, R7,  regs[R7p]);

		/* External status interrupt and FIFO control.  */
		write_zsreg(channel, R15, regs[R15] & ~WR7pEN);
		escc = 1;
	} else {
		 /* Clear FIFO bit case it is an issue */
		regs[R15] &= ~FIFOEN;
		escc = 0;
	}

	/* Reset external status interrupts.  */
	write_zsreg(channel, R0, RES_EXT_INT); /* First Latch  */
	write_zsreg(channel, R0, RES_EXT_INT); /* Second Latch */

	/* Rewrite R3/R5, this time without enables masked.  */
	write_zsreg(channel, R3, regs[R3]);
	write_zsreg(channel, R5, regs[R5]);

	/* Rewrite R1, this time without IRQ enabled masked.  */
	write_zsreg(channel, R1, regs[R1]);

	return escc;
}

/* Reprogram the Zilog channel HW registers with the copies found in the
 * software state struct.  If the transmitter is busy, we defer this update
 * until the next TX complete interrupt.  Else, we do it right now.
 *
 * The UART port lock must be held and local interrupts disabled.
 */
static void sunzilog_maybe_update_regs(struct uart_sunzilog_port *up,
				       struct zilog_channel __iomem *channel)
{
	if (!ZS_REGS_HELD(up)) {
		if (ZS_TX_ACTIVE(up)) {
			up->flags |= SUNZILOG_FLAG_REGS_HELD;
		} else {
			__load_zsregs(channel, up->curregs);
		}
	}
}

static void sunzilog_change_mouse_baud(struct uart_sunzilog_port *up)
{
	unsigned int cur_cflag = up->cflag;
	int brg, new_baud;

	up->cflag &= ~CBAUD;
	up->cflag |= suncore_mouse_baud_cflag_next(cur_cflag, &new_baud);

	brg = BPS_TO_BRG(new_baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
	up->curregs[R12] = (brg & 0xff);
	up->curregs[R13] = (brg >> 8) & 0xff;
	sunzilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(&up->port));
}

static void sunzilog_kbdms_receive_chars(struct uart_sunzilog_port *up,
					 unsigned char ch, int is_break)
{
	if (ZS_IS_KEYB(up)) {
		/* Stop-A is handled by drivers/char/keyboard.c now. */
#ifdef CONFIG_SERIO
		if (up->serio_open)
			serio_interrupt(&up->serio, ch, 0);
#endif
	} else if (ZS_IS_MOUSE(up)) {
		int ret = suncore_mouse_baud_detection(ch, is_break);

		switch (ret) {
		case 2:
			sunzilog_change_mouse_baud(up);
			fallthrough;
		case 1:
			break;

		case 0:
#ifdef CONFIG_SERIO
			if (up->serio_open)
				serio_interrupt(&up->serio, ch, 0);
#endif
			break;
		}
	}
}

static struct tty_port *
sunzilog_receive_chars(struct uart_sunzilog_port *up,
		       struct zilog_channel __iomem *channel)
{
	struct tty_port *port = NULL;
	unsigned char ch, r1, flag;

	if (up->port.state != NULL)		/* Unopened serial console */
		port = &up->port.state->port;

	for (;;) {

		r1 = read_zsreg(channel, R1);
		if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
			writeb(ERR_RES, &channel->control);
			ZSDELAY();
			ZS_WSYNC(channel);
		}

		ch = readb(&channel->control);
		ZSDELAY();

		/* This funny hack depends upon BRK_ABRT not interfering
		 * with the other bits we care about in R1.
		 */
		if (ch & BRK_ABRT)
			r1 |= BRK_ABRT;

		if (!(ch & Rx_CH_AV))
			break;

		ch = readb(&channel->data);
		ZSDELAY();

		ch &= up->parity_mask;

		if (unlikely(ZS_IS_KEYB(up)) || unlikely(ZS_IS_MOUSE(up))) {
			sunzilog_kbdms_receive_chars(up, ch, 0);
			continue;
		}

		/* A real serial line, record the character and status.  */
		flag = TTY_NORMAL;
		up->port.icount.rx++;
		if (r1 & (BRK_ABRT | PAR_ERR | Rx_OVR | CRC_ERR)) {
			if (r1 & BRK_ABRT) {
				r1 &= ~(PAR_ERR | CRC_ERR);
				up->port.icount.brk++;
				if (uart_handle_break(&up->port))
					continue;
			}
			else if (r1 & PAR_ERR)
				up->port.icount.parity++;
			else if (r1 & CRC_ERR)
				up->port.icount.frame++;
			if (r1 & Rx_OVR)
				up->port.icount.overrun++;
			r1 &= up->port.read_status_mask;
			if (r1 & BRK_ABRT)
				flag = TTY_BREAK;
			else if (r1 & PAR_ERR)
				flag = TTY_PARITY;
			else if (r1 & CRC_ERR)
				flag = TTY_FRAME;
		}
		if (uart_handle_sysrq_char(&up->port, ch) || !port)
			continue;

		if (up->port.ignore_status_mask == 0xff ||
		    (r1 & up->port.ignore_status_mask) == 0) {
		    	tty_insert_flip_char(port, ch, flag);
		}
		if (r1 & Rx_OVR)
			tty_insert_flip_char(port, 0, TTY_OVERRUN);
	}

	return port;
}

static void sunzilog_status_handle(struct uart_sunzilog_port *up,
				   struct zilog_channel __iomem *channel)
{
	unsigned char status;

	status = readb(&channel->control);
	ZSDELAY();

	writeb(RES_EXT_INT, &channel->control);
	ZSDELAY();
	ZS_WSYNC(channel);

	if (status & BRK_ABRT) {
		if (ZS_IS_MOUSE(up))
			sunzilog_kbdms_receive_chars(up, 0, 1);
		if (ZS_IS_CONS(up)) {
			/* Wait for BREAK to deassert to avoid potentially
			 * confusing the PROM.
			 */
			while (1) {
				status = readb(&channel->control);
				ZSDELAY();
				if (!(status & BRK_ABRT))
					break;
			}
			sun_do_break();
			return;
		}
	}

	if (ZS_WANTS_MODEM_STATUS(up)) {
		if (status & SYNC)
			up->port.icount.dsr++;

		/* The Zilog just gives us an interrupt when DCD/CTS/etc. change.
		 * But it does not tell us which bit has changed, we have to keep
		 * track of this ourselves.
		 */
		if ((status ^ up->prev_status) ^ DCD)
			uart_handle_dcd_change(&up->port,
					       (status & DCD));
		if ((status ^ up->prev_status) ^ CTS)
			uart_handle_cts_change(&up->port,
					       (status & CTS));

		wake_up_interruptible(&up->port.state->port.delta_msr_wait);
	}

	up->prev_status = status;
}

static void sunzilog_transmit_chars(struct uart_sunzilog_port *up,
				    struct zilog_channel __iomem *channel)
{
	struct circ_buf *xmit;

	if (ZS_IS_CONS(up)) {
		unsigned char status = readb(&channel->control);
		ZSDELAY();

		/* TX still busy?  Just wait for the next TX done interrupt.
		 *
		 * It can occur because of how we do serial console writes.  It would
		 * be nice to transmit console writes just like we normally would for
		 * a TTY line. (ie. buffered and TX interrupt driven).  That is not
		 * easy because console writes cannot sleep.  One solution might be
		 * to poll on enough port->xmit space becoming free.  -DaveM
		 */
		if (!(status & Tx_BUF_EMP))
			return;
	}

	up->flags &= ~SUNZILOG_FLAG_TX_ACTIVE;

	if (ZS_REGS_HELD(up)) {
		__load_zsregs(channel, up->curregs);
		up->flags &= ~SUNZILOG_FLAG_REGS_HELD;
	}

	if (ZS_TX_STOPPED(up)) {
		up->flags &= ~SUNZILOG_FLAG_TX_STOPPED;
		goto ack_tx_int;
	}

	if (up->port.x_char) {
		up->flags |= SUNZILOG_FLAG_TX_ACTIVE;
		writeb(up->port.x_char, &channel->data);
		ZSDELAY();
		ZS_WSYNC(channel);

		up->port.icount.tx++;
		up->port.x_char = 0;
		return;
	}

	if (up->port.state == NULL)
		goto ack_tx_int;
	xmit = &up->port.state->xmit;
	if (uart_circ_empty(xmit))
		goto ack_tx_int;

	if (uart_tx_stopped(&up->port))
		goto ack_tx_int;

	up->flags |= SUNZILOG_FLAG_TX_ACTIVE;
	writeb(xmit->buf[xmit->tail], &channel->data);
	ZSDELAY();
	ZS_WSYNC(channel);

	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
	up->port.icount.tx++;

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(&up->port);

	return;

ack_tx_int:
	writeb(RES_Tx_P, &channel->control);
	ZSDELAY();
	ZS_WSYNC(channel);
}

static irqreturn_t sunzilog_interrupt(int irq, void *dev_id)
{
	struct uart_sunzilog_port *up = dev_id;

	while (up) {
		struct zilog_channel __iomem *channel
			= ZILOG_CHANNEL_FROM_PORT(&up->port);
		struct tty_port *port;
		unsigned char r3;

		spin_lock(&up->port.lock);
		r3 = read_zsreg(channel, R3);

		/* Channel A */
		port = NULL;
		if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
			writeb(RES_H_IUS, &channel->control);
			ZSDELAY();
			ZS_WSYNC(channel);

			if (r3 & CHARxIP)
				port = sunzilog_receive_chars(up, channel);
			if (r3 & CHAEXT)
				sunzilog_status_handle(up, channel);
			if (r3 & CHATxIP)
				sunzilog_transmit_chars(up, channel);
		}
		spin_unlock(&up->port.lock);

		if (port)
			tty_flip_buffer_push(port);

		/* Channel B */
		up = up->next;
		channel = ZILOG_CHANNEL_FROM_PORT(&up->port);

		spin_lock(&up->port.lock);
		port = NULL;
		if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
			writeb(RES_H_IUS, &channel->control);
			ZSDELAY();
			ZS_WSYNC(channel);

			if (r3 & CHBRxIP)
				port = sunzilog_receive_chars(up, channel);
			if (r3 & CHBEXT)
				sunzilog_status_handle(up, channel);
			if (r3 & CHBTxIP)
				sunzilog_transmit_chars(up, channel);
		}
		spin_unlock(&up->port.lock);

		if (port)
			tty_flip_buffer_push(port);

		up = up->next;
	}

	return IRQ_HANDLED;
}

/* A convenient way to quickly get R0 status.  The caller must _not_ hold the
 * port lock, it is acquired here.
 */
static __inline__ unsigned char sunzilog_read_channel_status(struct uart_port *port)
{
	struct zilog_channel __iomem *channel;
	unsigned char status;

	channel = ZILOG_CHANNEL_FROM_PORT(port);
	status = readb(&channel->control);
	ZSDELAY();

	return status;
}

/* The port lock is not held.  */
static unsigned int sunzilog_tx_empty(struct uart_port *port)
{
	unsigned long flags;
	unsigned char status;
	unsigned int ret;

	spin_lock_irqsave(&port->lock, flags);

	status = sunzilog_read_channel_status(port);

	spin_unlock_irqrestore(&port->lock, flags);

	if (status & Tx_BUF_EMP)
		ret = TIOCSER_TEMT;
	else
		ret = 0;

	return ret;
}

/* The port lock is held and interrupts are disabled.  */
static unsigned int sunzilog_get_mctrl(struct uart_port *port)
{
	unsigned char status;
	unsigned int ret;

	status = sunzilog_read_channel_status(port);

	ret = 0;
	if (status & DCD)
		ret |= TIOCM_CAR;
	if (status & SYNC)
		ret |= TIOCM_DSR;
	if (status & CTS)
		ret |= TIOCM_CTS;

	return ret;
}

/* The port lock is held and interrupts are disabled.  */
static void sunzilog_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	struct uart_sunzilog_port *up =
		container_of(port, struct uart_sunzilog_port, port);
	struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
	unsigned char set_bits, clear_bits;

	set_bits = clear_bits = 0;

	if (mctrl & TIOCM_RTS)
		set_bits |= RTS;
	else
		clear_bits |= RTS;
	if (mctrl & TIOCM_DTR)
		set_bits |= DTR;
	else
		clear_bits |= DTR;

	/* NOTE: Not subject to 'transmitter active' rule.  */ 
	up->curregs[R5] |= set_bits;
	up->curregs[R5] &= ~clear_bits;
	write_zsreg(channel, R5, up->curregs[R5]);
}

/* The port lock is held and interrupts are disabled.  */
static void sunzilog_stop_tx(struct uart_port *port)
{
	struct uart_sunzilog_port *up =
		container_of(port, struct uart_sunzilog_port, port);

	up->flags |= SUNZILOG_FLAG_TX_STOPPED;
}

/* The port lock is held and interrupts are disabled.  */
static void sunzilog_start_tx(struct uart_port *port)
{
	struct uart_sunzilog_port *up =
		container_of(port, struct uart_sunzilog_port, port);
	struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
	unsigned char status;

	up->flags |= SUNZILOG_FLAG_TX_ACTIVE;
	up->flags &= ~SUNZILOG_FLAG_TX_STOPPED;

	status = readb(&channel->control);
	ZSDELAY();

	/* TX busy?  Just wait for the TX done interrupt.  */
	if (!(status & Tx_BUF_EMP))
		return;

	/* Send the first character to jump-start the TX done
	 * IRQ sending engine.
	 */
	if (port->x_char) {
		writeb(port->x_char, &channel->data);
		ZSDELAY();
		ZS_WSYNC(channel);

		port->icount.tx++;
		port->x_char = 0;
	} else {
		struct circ_buf *xmit = &port->state->xmit;

		if (uart_circ_empty(xmit))
			return;
		writeb(xmit->buf[xmit->tail], &channel->data);
		ZSDELAY();
		ZS_WSYNC(channel);

		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;

		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
			uart_write_wakeup(&up->port);
	}
}

/* The port lock is held.  */
static void sunzilog_stop_rx(struct uart_port *port)
{
	struct uart_sunzilog_port *up = UART_ZILOG(port);
	struct zilog_channel __iomem *channel;

	if (ZS_IS_CONS(up))
		return;

	channel = ZILOG_CHANNEL_FROM_PORT(port);

	/* Disable all RX interrupts.  */
	up->curregs[R1] &= ~RxINT_MASK;
	sunzilog_maybe_update_regs(up, channel);
}

/* The port lock is held.  */
static void sunzilog_enable_ms(struct uart_port *port)
{
	struct uart_sunzilog_port *up =
		container_of(port, struct uart_sunzilog_port, port);
	struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
	unsigned char new_reg;

	new_reg = up->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
	if (new_reg != up->curregs[R15]) {
		up->curregs[R15] = new_reg;

		/* NOTE: Not subject to 'transmitter active' rule.  */ 
		write_zsreg(channel, R15, up->curregs[R15] & ~WR7pEN);
	}
}

/* The port lock is not held.  */
static void sunzilog_break_ctl(struct uart_port *port, int break_state)
{
	struct uart_sunzilog_port *up =
		container_of(port, struct uart_sunzilog_port, port);
	struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
	unsigned char set_bits, clear_bits, new_reg;
	unsigned long flags;

	set_bits = clear_bits = 0;

	if (break_state)
		set_bits |= SND_BRK;
	else
		clear_bits |= SND_BRK;

	spin_lock_irqsave(&port->lock, flags);

	new_reg = (up->curregs[R5] | set_bits) & ~clear_bits;
	if (new_reg != up->curregs[R5]) {
		up->curregs[R5] = new_reg;

		/* NOTE: Not subject to 'transmitter active' rule.  */ 
		write_zsreg(channel, R5, up->curregs[R5]);
	}

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

static void __sunzilog_startup(struct uart_sunzilog_port *up)
{
	struct zilog_channel __iomem *channel;

	channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
	up->prev_status = readb(&channel->control);

	/* Enable receiver and transmitter.  */
	up->curregs[R3] |= RxENAB;
	up->curregs[R5] |= TxENAB;

	up->curregs[R1] |= EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
	sunzilog_maybe_update_regs(up, channel);
}

static int sunzilog_startup(struct uart_port *port)
{
	struct uart_sunzilog_port *up = UART_ZILOG(port);
	unsigned long flags;

	if (ZS_IS_CONS(up))
		return 0;

	spin_lock_irqsave(&port->lock, flags);
	__sunzilog_startup(up);
	spin_unlock_irqrestore(&port->lock, flags);
	return 0;
}

/*
 * The test for ZS_IS_CONS is explained by the following e-mail:
 *****
 * From: Russell King <rmk@arm.linux.org.uk>
 * Date: Sun, 8 Dec 2002 10:18:38 +0000
 *
 * On Sun, Dec 08, 2002 at 02:43:36AM -0500, Pete Zaitcev wrote:
 * > I boot my 2.5 boxes using "console=ttyS0,9600" argument,
 * > and I noticed that something is not right with reference
 * > counting in this case. It seems that when the console
 * > is open by kernel initially, this is not accounted
 * > as an open, and uart_startup is not called.
 *
 * That is correct.  We are unable to call uart_startup when the serial
 * console is initialised because it may need to allocate memory (as
 * request_irq does) and the memory allocators may not have been
 * initialised.
 *
 * 1. initialise the port into a state where it can send characters in the
 *    console write method.
 *
 * 2. don't do the actual hardware shutdown in your shutdown() method (but
 *    do the normal software shutdown - ie, free irqs etc)
 *****
 */
static void sunzilog_shutdown(struct uart_port *port)
{
	struct uart_sunzilog_port *up = UART_ZILOG(port);
	struct zilog_channel __iomem *channel;
	unsigned long flags;

	if (ZS_IS_CONS(up))
		return;

	spin_lock_irqsave(&port->lock, flags);

	channel = ZILOG_CHANNEL_FROM_PORT(port);

	/* Disable receiver and transmitter.  */
	up->curregs[R3] &= ~RxENAB;
	up->curregs[R5] &= ~TxENAB;

	/* Disable all interrupts and BRK assertion.  */
	up->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
	up->curregs[R5] &= ~SND_BRK;
	sunzilog_maybe_update_regs(up, channel);

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

/* Shared by TTY driver and serial console setup.  The port lock is held
 * and local interrupts are disabled.
 */
static void
sunzilog_convert_to_zs(struct uart_sunzilog_port *up, unsigned int cflag,
		       unsigned int iflag, int brg)
{

	up->curregs[R10] = NRZ;
	up->curregs[R11] = TCBR | RCBR;

	/* Program BAUD and clock source. */
	up->curregs[R4] &= ~XCLK_MASK;
	up->curregs[R4] |= X16CLK;
	up->curregs[R12] = brg & 0xff;
	up->curregs[R13] = (brg >> 8) & 0xff;
	up->curregs[R14] = BRSRC | BRENAB;

	/* Character size, stop bits, and parity. */
	up->curregs[R3] &= ~RxN_MASK;
	up->curregs[R5] &= ~TxN_MASK;
	switch (cflag & CSIZE) {
	case CS5:
		up->curregs[R3] |= Rx5;
		up->curregs[R5] |= Tx5;
		up->parity_mask = 0x1f;
		break;
	case CS6:
		up->curregs[R3] |= Rx6;
		up->curregs[R5] |= Tx6;
		up->parity_mask = 0x3f;
		break;
	case CS7:
		up->curregs[R3] |= Rx7;
		up->curregs[R5] |= Tx7;
		up->parity_mask = 0x7f;
		break;
	case CS8:
	default:
		up->curregs[R3] |= Rx8;
		up->curregs[R5] |= Tx8;
		up->parity_mask = 0xff;
		break;
	}
	up->curregs[R4] &= ~0x0c;
	if (cflag & CSTOPB)
		up->curregs[R4] |= SB2;
	else
		up->curregs[R4] |= SB1;
	if (cflag & PARENB)
		up->curregs[R4] |= PAR_ENAB;
	else
		up->curregs[R4] &= ~PAR_ENAB;
	if (!(cflag & PARODD))
		up->curregs[R4] |= PAR_EVEN;
	else
		up->curregs[R4] &= ~PAR_EVEN;

	up->port.read_status_mask = Rx_OVR;
	if (iflag & INPCK)
		up->port.read_status_mask |= CRC_ERR | PAR_ERR;
	if (iflag & (IGNBRK | BRKINT | PARMRK))
		up->port.read_status_mask |= BRK_ABRT;

	up->port.ignore_status_mask = 0;
	if (iflag & IGNPAR)
		up->port.ignore_status_mask |= CRC_ERR | PAR_ERR;
	if (iflag & IGNBRK) {
		up->port.ignore_status_mask |= BRK_ABRT;
		if (iflag & IGNPAR)
			up->port.ignore_status_mask |= Rx_OVR;
	}

	if ((cflag & CREAD) == 0)
		up->port.ignore_status_mask = 0xff;
}

/* The port lock is not held.  */
static void
sunzilog_set_termios(struct uart_port *port, struct ktermios *termios,
		     const struct ktermios *old)
{
	struct uart_sunzilog_port *up =
		container_of(port, struct uart_sunzilog_port, port);
	unsigned long flags;
	int baud, brg;

	baud = uart_get_baud_rate(port, termios, old, 1200, 76800);

	spin_lock_irqsave(&up->port.lock, flags);

	brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);

	sunzilog_convert_to_zs(up, termios->c_cflag, termios->c_iflag, brg);

	if (UART_ENABLE_MS(&up->port, termios->c_cflag))
		up->flags |= SUNZILOG_FLAG_MODEM_STATUS;
	else
		up->flags &= ~SUNZILOG_FLAG_MODEM_STATUS;

	up->cflag = termios->c_cflag;

	sunzilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port));

	uart_update_timeout(port, termios->c_cflag, baud);

	spin_unlock_irqrestore(&up->port.lock, flags);
}

static const char *sunzilog_type(struct uart_port *port)
{
	struct uart_sunzilog_port *up = UART_ZILOG(port);

	return (up->flags & SUNZILOG_FLAG_ESCC) ? "zs (ESCC)" : "zs";
}

/* We do not request/release mappings of the registers here, this
 * happens at early serial probe time.
 */
static void sunzilog_release_port(struct uart_port *port)
{
}

static int sunzilog_request_port(struct uart_port *port)
{
	return 0;
}

/* These do not need to do anything interesting either.  */
static void sunzilog_config_port(struct uart_port *port, int flags)
{
}

/* We do not support letting the user mess with the divisor, IRQ, etc. */
static int sunzilog_verify_port(struct uart_port *port, struct serial_struct *ser)
{
	return -EINVAL;
}

#ifdef CONFIG_CONSOLE_POLL
static int sunzilog_get_poll_char(struct uart_port *port)
{
	unsigned char ch, r1;
	struct uart_sunzilog_port *up =
		container_of(port, struct uart_sunzilog_port, port);
	struct zilog_channel __iomem *channel
		= ZILOG_CHANNEL_FROM_PORT(&up->port);


	r1 = read_zsreg(channel, R1);
	if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
		writeb(ERR_RES, &channel->control);
		ZSDELAY();
		ZS_WSYNC(channel);
	}

	ch = readb(&channel->control);
	ZSDELAY();

	/* This funny hack depends upon BRK_ABRT not interfering
	 * with the other bits we care about in R1.
	 */
	if (ch & BRK_ABRT)
		r1 |= BRK_ABRT;

	if (!(ch & Rx_CH_AV))
		return NO_POLL_CHAR;

	ch = readb(&channel->data);
	ZSDELAY();

	ch &= up->parity_mask;
	return ch;
}

static void sunzilog_put_poll_char(struct uart_port *port,
			unsigned char ch)
{
	struct uart_sunzilog_port *up =
		container_of(port, struct uart_sunzilog_port, port);

	sunzilog_putchar(&up->port, ch);
}
#endif /* CONFIG_CONSOLE_POLL */

static const struct uart_ops sunzilog_pops = {
	.tx_empty	=	sunzilog_tx_empty,
	.set_mctrl	=	sunzilog_set_mctrl,
	.get_mctrl	=	sunzilog_get_mctrl,
	.stop_tx	=	sunzilog_stop_tx,
	.start_tx	=	sunzilog_start_tx,
	.stop_rx	=	sunzilog_stop_rx,
	.enable_ms	=	sunzilog_enable_ms,
	.break_ctl	=	sunzilog_break_ctl,
	.startup	=	sunzilog_startup,
	.shutdown	=	sunzilog_shutdown,
	.set_termios	=	sunzilog_set_termios,
	.type		=	sunzilog_type,
	.release_port	=	sunzilog_release_port,
	.request_port	=	sunzilog_request_port,
	.config_port	=	sunzilog_config_port,
	.verify_port	=	sunzilog_verify_port,
#ifdef CONFIG_CONSOLE_POLL
	.poll_get_char	=	sunzilog_get_poll_char,
	.poll_put_char	=	sunzilog_put_poll_char,
#endif
};

static int uart_chip_count;
static struct uart_sunzilog_port *sunzilog_port_table;
static struct zilog_layout __iomem **sunzilog_chip_regs;

static struct uart_sunzilog_port *sunzilog_irq_chain;

static struct uart_driver sunzilog_reg = {
	.owner		=	THIS_MODULE,
	.driver_name	=	"sunzilog",
	.dev_name	=	"ttyS",
	.major		=	TTY_MAJOR,
};

static int __init sunzilog_alloc_tables(int num_sunzilog)
{
	struct uart_sunzilog_port *up;
	unsigned long size;
	int num_channels = num_sunzilog * 2;
	int i;

	size = num_channels * sizeof(struct uart_sunzilog_port);
	sunzilog_port_table = kzalloc(size, GFP_KERNEL);
	if (!sunzilog_port_table)
		return -ENOMEM;

	for (i = 0; i < num_channels; i++) {
		up = &sunzilog_port_table[i];

		spin_lock_init(&up->port.lock);

		if (i == 0)
			sunzilog_irq_chain = up;

		if (i < num_channels - 1)
			up->next = up + 1;
		else
			up->next = NULL;
	}

	size = num_sunzilog * sizeof(struct zilog_layout __iomem *);
	sunzilog_chip_regs = kzalloc(size, GFP_KERNEL);
	if (!sunzilog_chip_regs) {
		kfree(sunzilog_port_table);
		sunzilog_irq_chain = NULL;
		return -ENOMEM;
	}

	return 0;
}

static void sunzilog_free_tables(void)
{
	kfree(sunzilog_port_table);
	sunzilog_irq_chain = NULL;
	kfree(sunzilog_chip_regs);
}

#define ZS_PUT_CHAR_MAX_DELAY	2000	/* 10 ms */

static void __maybe_unused sunzilog_putchar(struct uart_port *port, unsigned char ch)
{
	struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
	int loops = ZS_PUT_CHAR_MAX_DELAY;

	/* This is a timed polling loop so do not switch the explicit
	 * udelay with ZSDELAY as that is a NOP on some platforms.  -DaveM
	 */
	do {
		unsigned char val = readb(&channel->control);
		if (val & Tx_BUF_EMP) {
			ZSDELAY();
			break;
		}
		udelay(5);
	} while (--loops);

	writeb(ch, &channel->data);
	ZSDELAY();
	ZS_WSYNC(channel);
}

#ifdef CONFIG_SERIO

static DEFINE_SPINLOCK(sunzilog_serio_lock);

static int sunzilog_serio_write(struct serio *serio, unsigned char ch)
{
	struct uart_sunzilog_port *up = serio->port_data;
	unsigned long flags;

	spin_lock_irqsave(&sunzilog_serio_lock, flags);

	sunzilog_putchar(&up->port, ch);

	spin_unlock_irqrestore(&sunzilog_serio_lock, flags);

	return 0;
}

static int sunzilog_serio_open(struct serio *serio)
{
	struct uart_sunzilog_port *up = serio->port_data;
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&sunzilog_serio_lock, flags);
	if (!up->serio_open) {
		up->serio_open = 1;
		ret = 0;
	} else
		ret = -EBUSY;
	spin_unlock_irqrestore(&sunzilog_serio_lock, flags);

	return ret;
}

static void sunzilog_serio_close(struct serio *serio)
{
	struct uart_sunzilog_port *up = serio->port_data;
	unsigned long flags;

	spin_lock_irqsave(&sunzilog_serio_lock, flags);
	up->serio_open = 0;
	spin_unlock_irqrestore(&sunzilog_serio_lock, flags);
}

#endif /* CONFIG_SERIO */

#ifdef CONFIG_SERIAL_SUNZILOG_CONSOLE
static void
sunzilog_console_write(struct console *con, const char *s, unsigned int count)
{
	struct uart_sunzilog_port *up = &sunzilog_port_table[con->index];
	unsigned long flags;
	int locked = 1;

	if (up->port.sysrq || oops_in_progress)
		locked = spin_trylock_irqsave(&up->port.lock, flags);
	else
		spin_lock_irqsave(&up->port.lock, flags);

	uart_console_write(&up->port, s, count, sunzilog_putchar);
	udelay(2);

	if (locked)
		spin_unlock_irqrestore(&up->port.lock, flags);
}

static int __init sunzilog_console_setup(struct console *con, char *options)
{
	struct uart_sunzilog_port *up = &sunzilog_port_table[con->index];
	unsigned long flags;
	int baud, brg;

	if (up->port.type != PORT_SUNZILOG)
		return -EINVAL;

	printk(KERN_INFO "Console: ttyS%d (SunZilog zs%d)\n",
	       (sunzilog_reg.minor - 64) + con->index, con->index);

	/* Get firmware console settings.  */
	sunserial_console_termios(con, up->port.dev->of_node);

	/* Firmware console speed is limited to 150-->38400 baud so
	 * this hackish cflag thing is OK.
	 */
	switch (con->cflag & CBAUD) {
	case B150: baud = 150; break;
	case B300: baud = 300; break;
	case B600: baud = 600; break;
	case B1200: baud = 1200; break;
	case B2400: baud = 2400; break;
	case B4800: baud = 4800; break;
	default: case B9600: baud = 9600; break;
	case B19200: baud = 19200; break;
	case B38400: baud = 38400; break;
	}

	brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);

	spin_lock_irqsave(&up->port.lock, flags);

	up->curregs[R15] |= BRKIE;
	sunzilog_convert_to_zs(up, con->cflag, 0, brg);

	sunzilog_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS);
	__sunzilog_startup(up);

	spin_unlock_irqrestore(&up->port.lock, flags);

	return 0;
}

static struct console sunzilog_console_ops = {
	.name	=	"ttyS",
	.write	=	sunzilog_console_write,
	.device	=	uart_console_device,
	.setup	=	sunzilog_console_setup,
	.flags	=	CON_PRINTBUFFER,
	.index	=	-1,
	.data   =	&sunzilog_reg,
};

static inline struct console *SUNZILOG_CONSOLE(void)
{
	return &sunzilog_console_ops;
}

#else
#define SUNZILOG_CONSOLE()	(NULL)
#endif

static void sunzilog_init_kbdms(struct uart_sunzilog_port *up)
{
	int baud, brg;

	if (up->flags & SUNZILOG_FLAG_CONS_KEYB) {
		up->cflag = B1200 | CS8 | CLOCAL | CREAD;
		baud = 1200;
	} else {
		up->cflag = B4800 | CS8 | CLOCAL | CREAD;
		baud = 4800;
	}

	up->curregs[R15] |= BRKIE;
	brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
	sunzilog_convert_to_zs(up, up->cflag, 0, brg);
	sunzilog_set_mctrl(&up->port, TIOCM_DTR | TIOCM_RTS);
	__sunzilog_startup(up);
}

#ifdef CONFIG_SERIO
static void sunzilog_register_serio(struct uart_sunzilog_port *up)
{
	struct serio *serio = &up->serio;

	serio->port_data = up;

	serio->id.type = SERIO_RS232;
	if (up->flags & SUNZILOG_FLAG_CONS_KEYB) {
		serio->id.proto = SERIO_SUNKBD;
		strscpy(serio->name, "zskbd", sizeof(serio->name));
	} else {
		serio->id.proto = SERIO_SUN;
		serio->id.extra = 1;
		strscpy(serio->name, "zsms", sizeof(serio->name));
	}
	strscpy(serio->phys,
		((up->flags & SUNZILOG_FLAG_CONS_KEYB) ?
		 "zs/serio0" : "zs/serio1"),
		sizeof(serio->phys));

	serio->write = sunzilog_serio_write;
	serio->open = sunzilog_serio_open;
	serio->close = sunzilog_serio_close;
	serio->dev.parent = up->port.dev;

	serio_register_port(serio);
}
#endif

static void sunzilog_init_hw(struct uart_sunzilog_port *up)
{
	struct zilog_channel __iomem *channel;
	unsigned long flags;
	int baud, brg;

	channel = ZILOG_CHANNEL_FROM_PORT(&up->port);

	spin_lock_irqsave(&up->port.lock, flags);
	if (ZS_IS_CHANNEL_A(up)) {
		write_zsreg(channel, R9, FHWRES);
		ZSDELAY_LONG();
		(void) read_zsreg(channel, R0);
	}

	if (up->flags & (SUNZILOG_FLAG_CONS_KEYB |
			 SUNZILOG_FLAG_CONS_MOUSE)) {
		up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
		up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
		up->curregs[R3] = RxENAB | Rx8;
		up->curregs[R5] = TxENAB | Tx8;
		up->curregs[R6] = 0x00; /* SDLC Address */
		up->curregs[R7] = 0x7E; /* SDLC Flag    */
		up->curregs[R9] = NV;
		up->curregs[R7p] = 0x00;
		sunzilog_init_kbdms(up);
		/* Only enable interrupts if an ISR handler available */
		if (up->flags & SUNZILOG_FLAG_ISR_HANDLER)
			up->curregs[R9] |= MIE;
		write_zsreg(channel, R9, up->curregs[R9]);
	} else {
		/* Normal serial TTY. */
		up->parity_mask = 0xff;
		up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
		up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
		up->curregs[R3] = RxENAB | Rx8;
		up->curregs[R5] = TxENAB | Tx8;
		up->curregs[R6] = 0x00; /* SDLC Address */
		up->curregs[R7] = 0x7E; /* SDLC Flag    */
		up->curregs[R9] = NV;
		up->curregs[R10] = NRZ;
		up->curregs[R11] = TCBR | RCBR;
		baud = 9600;
		brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
		up->curregs[R12] = (brg & 0xff);
		up->curregs[R13] = (brg >> 8) & 0xff;
		up->curregs[R14] = BRSRC | BRENAB;
		up->curregs[R15] = FIFOEN; /* Use FIFO if on ESCC */
		up->curregs[R7p] = TxFIFO_LVL | RxFIFO_LVL;
		if (__load_zsregs(channel, up->curregs)) {
			up->flags |= SUNZILOG_FLAG_ESCC;
		}
		/* Only enable interrupts if an ISR handler available */
		if (up->flags & SUNZILOG_FLAG_ISR_HANDLER)
			up->curregs[R9] |= MIE;
		write_zsreg(channel, R9, up->curregs[R9]);
	}

	spin_unlock_irqrestore(&up->port.lock, flags);

#ifdef CONFIG_SERIO
	if (up->flags & (SUNZILOG_FLAG_CONS_KEYB |
			 SUNZILOG_FLAG_CONS_MOUSE))
		sunzilog_register_serio(up);
#endif
}

static int zilog_irq;

static int zs_probe(struct platform_device *op)
{
	static int kbm_inst, uart_inst;
	int inst;
	struct uart_sunzilog_port *up;
	struct zilog_layout __iomem *rp;
	int keyboard_mouse = 0;
	int err;

	if (of_find_property(op->dev.of_node, "keyboard", NULL))
		keyboard_mouse = 1;

	/* uarts must come before keyboards/mice */
	if (keyboard_mouse)
		inst = uart_chip_count + kbm_inst;
	else
		inst = uart_inst;

	sunzilog_chip_regs[inst] = of_ioremap(&op->resource[0], 0,
					      sizeof(struct zilog_layout),
					      "zs");
	if (!sunzilog_chip_regs[inst])
		return -ENOMEM;

	rp = sunzilog_chip_regs[inst];

	if (!zilog_irq)
		zilog_irq = op->archdata.irqs[0];

	up = &sunzilog_port_table[inst * 2];

	/* Channel A */
	up[0].port.mapbase = op->resource[0].start + 0x00;
	up[0].port.membase = (void __iomem *) &rp->channelA;
	up[0].port.iotype = UPIO_MEM;
	up[0].port.irq = op->archdata.irqs[0];
	up[0].port.uartclk = ZS_CLOCK;
	up[0].port.fifosize = 1;
	up[0].port.ops = &sunzilog_pops;
	up[0].port.type = PORT_SUNZILOG;
	up[0].port.flags = 0;
	up[0].port.line = (inst * 2) + 0;
	up[0].port.dev = &op->dev;
	up[0].flags |= SUNZILOG_FLAG_IS_CHANNEL_A;
	up[0].port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_SUNZILOG_CONSOLE);
	if (keyboard_mouse)
		up[0].flags |= SUNZILOG_FLAG_CONS_KEYB;
	sunzilog_init_hw(&up[0]);

	/* Channel B */
	up[1].port.mapbase = op->resource[0].start + 0x04;
	up[1].port.membase = (void __iomem *) &rp->channelB;
	up[1].port.iotype = UPIO_MEM;
	up[1].port.irq = op->archdata.irqs[0];
	up[1].port.uartclk = ZS_CLOCK;
	up[1].port.fifosize = 1;
	up[1].port.ops = &sunzilog_pops;
	up[1].port.type = PORT_SUNZILOG;
	up[1].port.flags = 0;
	up[1].port.line = (inst * 2) + 1;
	up[1].port.dev = &op->dev;
	up[1].flags |= 0;
	up[1].port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_SUNZILOG_CONSOLE);
	if (keyboard_mouse)
		up[1].flags |= SUNZILOG_FLAG_CONS_MOUSE;
	sunzilog_init_hw(&up[1]);

	if (!keyboard_mouse) {
		if (sunserial_console_match(SUNZILOG_CONSOLE(), op->dev.of_node,
					    &sunzilog_reg, up[0].port.line,
					    false))
			up->flags |= SUNZILOG_FLAG_IS_CONS;
		err = uart_add_one_port(&sunzilog_reg, &up[0].port);
		if (err) {
			of_iounmap(&op->resource[0],
				   rp, sizeof(struct zilog_layout));
			return err;
		}
		if (sunserial_console_match(SUNZILOG_CONSOLE(), op->dev.of_node,
					    &sunzilog_reg, up[1].port.line,
					    false))
			up->flags |= SUNZILOG_FLAG_IS_CONS;
		err = uart_add_one_port(&sunzilog_reg, &up[1].port);
		if (err) {
			uart_remove_one_port(&sunzilog_reg, &up[0].port);
			of_iounmap(&op->resource[0],
				   rp, sizeof(struct zilog_layout));
			return err;
		}
		uart_inst++;
	} else {
		printk(KERN_INFO "%s: Keyboard at MMIO 0x%llx (irq = %d) "
		       "is a %s\n",
		       dev_name(&op->dev),
		       (unsigned long long) up[0].port.mapbase,
		       op->archdata.irqs[0], sunzilog_type(&up[0].port));
		printk(KERN_INFO "%s: Mouse at MMIO 0x%llx (irq = %d) "
		       "is a %s\n",
		       dev_name(&op->dev),
		       (unsigned long long) up[1].port.mapbase,
		       op->archdata.irqs[0], sunzilog_type(&up[1].port));
		kbm_inst++;
	}

	platform_set_drvdata(op, &up[0]);

	return 0;
}

static void zs_remove_one(struct uart_sunzilog_port *up)
{
	if (ZS_IS_KEYB(up) || ZS_IS_MOUSE(up)) {
#ifdef CONFIG_SERIO
		serio_unregister_port(&up->serio);
#endif
	} else
		uart_remove_one_port(&sunzilog_reg, &up->port);
}

static int zs_remove(struct platform_device *op)
{
	struct uart_sunzilog_port *up = platform_get_drvdata(op);
	struct zilog_layout __iomem *regs;

	zs_remove_one(&up[0]);
	zs_remove_one(&up[1]);

	regs = sunzilog_chip_regs[up[0].port.line / 2];
	of_iounmap(&op->resource[0], regs, sizeof(struct zilog_layout));

	return 0;
}

static const struct of_device_id zs_match[] = {
	{
		.name = "zs",
	},
	{},
};
MODULE_DEVICE_TABLE(of, zs_match);

static struct platform_driver zs_driver = {
	.driver = {
		.name = "zs",
		.of_match_table = zs_match,
	},
	.probe		= zs_probe,
	.remove		= zs_remove,
};

static int __init sunzilog_init(void)
{
	struct device_node *dp;
	int err;
	int num_keybms = 0;
	int num_sunzilog = 0;

	for_each_node_by_name(dp, "zs") {
		num_sunzilog++;
		if (of_find_property(dp, "keyboard", NULL))
			num_keybms++;
	}

	if (num_sunzilog) {
		err = sunzilog_alloc_tables(num_sunzilog);
		if (err)
			goto out;

		uart_chip_count = num_sunzilog - num_keybms;

		err = sunserial_register_minors(&sunzilog_reg,
						uart_chip_count * 2);
		if (err)
			goto out_free_tables;
	}

	err = platform_driver_register(&zs_driver);
	if (err)
		goto out_unregister_uart;

	if (zilog_irq) {
		struct uart_sunzilog_port *up = sunzilog_irq_chain;
		err = request_irq(zilog_irq, sunzilog_interrupt, IRQF_SHARED,
				  "zs", sunzilog_irq_chain);
		if (err)
			goto out_unregister_driver;

		/* Enable Interrupts */
		while (up) {
			struct zilog_channel __iomem *channel;

			/* printk (KERN_INFO "Enable IRQ for ZILOG Hardware %p\n", up); */
			channel          = ZILOG_CHANNEL_FROM_PORT(&up->port);
			up->flags       |= SUNZILOG_FLAG_ISR_HANDLER;
			up->curregs[R9] |= MIE;
			write_zsreg(channel, R9, up->curregs[R9]);
			up = up->next;
		}
	}

out:
	return err;

out_unregister_driver:
	platform_driver_unregister(&zs_driver);

out_unregister_uart:
	if (num_sunzilog) {
		sunserial_unregister_minors(&sunzilog_reg, num_sunzilog);
		sunzilog_reg.cons = NULL;
	}

out_free_tables:
	sunzilog_free_tables();
	goto out;
}

static void __exit sunzilog_exit(void)
{
	platform_driver_unregister(&zs_driver);

	if (zilog_irq) {
		struct uart_sunzilog_port *up = sunzilog_irq_chain;

		/* Disable Interrupts */
		while (up) {
			struct zilog_channel __iomem *channel;

			/* printk (KERN_INFO "Disable IRQ for ZILOG Hardware %p\n", up); */
			channel          = ZILOG_CHANNEL_FROM_PORT(&up->port);
			up->flags       &= ~SUNZILOG_FLAG_ISR_HANDLER;
			up->curregs[R9] &= ~MIE;
			write_zsreg(channel, R9, up->curregs[R9]);
			up = up->next;
		}

		free_irq(zilog_irq, sunzilog_irq_chain);
		zilog_irq = 0;
	}

	if (sunzilog_reg.nr) {
		sunserial_unregister_minors(&sunzilog_reg, sunzilog_reg.nr);
		sunzilog_free_tables();
	}
}

module_init(sunzilog_init);
module_exit(sunzilog_exit);

MODULE_AUTHOR("David S. Miller");
MODULE_DESCRIPTION("Sun Zilog serial port driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");