Bootlin logo

Elixir Cross Referencer

   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
/*
 * 3215 line mode terminal driver.
 *
 * Copyright IBM Corp. 1999, 2009
 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 *
 * Updated:
 *  Aug-2000: Added tab support
 *	      Dan Morrison, IBM Corporation <dmorriso@cse.buffalo.edu>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kdev_t.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/vt_kern.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/reboot.h>
#include <linux/serial.h> /* ASYNC_* flags */
#include <linux/slab.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/io.h>
#include <asm/ebcdic.h>
#include <asm/uaccess.h>
#include <asm/delay.h>
#include <asm/cpcmd.h>
#include <asm/setup.h>

#include "ctrlchar.h"

#define NR_3215		    1
#define NR_3215_REQ	    (4*NR_3215)
#define RAW3215_BUFFER_SIZE 65536     /* output buffer size */
#define RAW3215_INBUF_SIZE  256	      /* input buffer size */
#define RAW3215_MIN_SPACE   128	      /* minimum free space for wakeup */
#define RAW3215_MIN_WRITE   1024      /* min. length for immediate output */
#define RAW3215_MAX_BYTES   3968      /* max. bytes to write with one ssch */
#define RAW3215_MAX_NEWLINE 50	      /* max. lines to write with one ssch */
#define RAW3215_NR_CCWS	    3
#define RAW3215_TIMEOUT	    HZ/10     /* time for delayed output */

#define RAW3215_FIXED	    1	      /* 3215 console device is not be freed */
#define RAW3215_WORKING	    4	      /* set if a request is being worked on */
#define RAW3215_THROTTLED   8	      /* set if reading is disabled */
#define RAW3215_STOPPED	    16	      /* set if writing is disabled */
#define RAW3215_TIMER_RUNS  64	      /* set if the output delay timer is on */
#define RAW3215_FLUSHING    128	      /* set to flush buffer (no delay) */

#define TAB_STOP_SIZE	    8	      /* tab stop size */

/*
 * Request types for a 3215 device
 */
enum raw3215_type {
	RAW3215_FREE, RAW3215_READ, RAW3215_WRITE
};

/*
 * Request structure for a 3215 device
 */
struct raw3215_req {
	enum raw3215_type type;	      /* type of the request */
	int start, len;		      /* start index & len in output buffer */
	int delayable;		      /* indication to wait for more data */
	int residual;		      /* residual count for read request */
	struct ccw1 ccws[RAW3215_NR_CCWS]; /* space for the channel program */
	struct raw3215_info *info;    /* pointer to main structure */
	struct raw3215_req *next;     /* pointer to next request */
} __attribute__ ((aligned(8)));

struct raw3215_info {
	struct tty_port port;
	struct ccw_device *cdev;      /* device for tty driver */
	spinlock_t *lock;	      /* pointer to irq lock */
	int flags;		      /* state flags */
	char *buffer;		      /* pointer to output buffer */
	char *inbuf;		      /* pointer to input buffer */
	int head;		      /* first free byte in output buffer */
	int count;		      /* number of bytes in output buffer */
	int written;		      /* number of bytes in write requests */
	struct raw3215_req *queued_read; /* pointer to queued read requests */
	struct raw3215_req *queued_write;/* pointer to queued write requests */
	struct tasklet_struct tlet;   /* tasklet to invoke tty_wakeup */
	wait_queue_head_t empty_wait; /* wait queue for flushing */
	struct timer_list timer;      /* timer for delayed output */
	int line_pos;		      /* position on the line (for tabs) */
	char ubuffer[80];	      /* copy_from_user buffer */
};

/* array of 3215 devices structures */
static struct raw3215_info *raw3215[NR_3215];
/* spinlock to protect the raw3215 array */
static DEFINE_SPINLOCK(raw3215_device_lock);
/* list of free request structures */
static struct raw3215_req *raw3215_freelist;
/* spinlock to protect free list */
static spinlock_t raw3215_freelist_lock;

static struct tty_driver *tty3215_driver;

/*
 * Get a request structure from the free list
 */
static inline struct raw3215_req *raw3215_alloc_req(void)
{
	struct raw3215_req *req;
	unsigned long flags;

	spin_lock_irqsave(&raw3215_freelist_lock, flags);
	req = raw3215_freelist;
	raw3215_freelist = req->next;
	spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
	return req;
}

/*
 * Put a request structure back to the free list
 */
static inline void raw3215_free_req(struct raw3215_req *req)
{
	unsigned long flags;

	if (req->type == RAW3215_FREE)
		return;		/* don't free a free request */
	req->type = RAW3215_FREE;
	spin_lock_irqsave(&raw3215_freelist_lock, flags);
	req->next = raw3215_freelist;
	raw3215_freelist = req;
	spin_unlock_irqrestore(&raw3215_freelist_lock, flags);
}

/*
 * Set up a read request that reads up to 160 byte from the 3215 device.
 * If there is a queued read request it is used, but that shouldn't happen
 * because a 3215 terminal won't accept a new read before the old one is
 * completed.
 */
static void raw3215_mk_read_req(struct raw3215_info *raw)
{
	struct raw3215_req *req;
	struct ccw1 *ccw;

	/* there can only be ONE read request at a time */
	req = raw->queued_read;
	if (req == NULL) {
		/* no queued read request, use new req structure */
		req = raw3215_alloc_req();
		req->type = RAW3215_READ;
		req->info = raw;
		raw->queued_read = req;
	}

	ccw = req->ccws;
	ccw->cmd_code = 0x0A; /* read inquiry */
	ccw->flags = 0x20;    /* ignore incorrect length */
	ccw->count = 160;
	ccw->cda = (__u32) __pa(raw->inbuf);
}

/*
 * Set up a write request with the information from the main structure.
 * A ccw chain is created that writes as much as possible from the output
 * buffer to the 3215 device. If a queued write exists it is replaced by
 * the new, probably lengthened request.
 */
static void raw3215_mk_write_req(struct raw3215_info *raw)
{
	struct raw3215_req *req;
	struct ccw1 *ccw;
	int len, count, ix, lines;

	if (raw->count <= raw->written)
		return;
	/* check if there is a queued write request */
	req = raw->queued_write;
	if (req == NULL) {
		/* no queued write request, use new req structure */
		req = raw3215_alloc_req();
		req->type = RAW3215_WRITE;
		req->info = raw;
		raw->queued_write = req;
	} else {
		raw->written -= req->len;
	}

	ccw = req->ccws;
	req->start = (raw->head - raw->count + raw->written) &
		     (RAW3215_BUFFER_SIZE - 1);
	/*
	 * now we have to count newlines. We can at max accept
	 * RAW3215_MAX_NEWLINE newlines in a single ssch due to
	 * a restriction in VM
	 */
	lines = 0;
	ix = req->start;
	while (lines < RAW3215_MAX_NEWLINE && ix != raw->head) {
		if (raw->buffer[ix] == 0x15)
			lines++;
		ix = (ix + 1) & (RAW3215_BUFFER_SIZE - 1);
	}
	len = ((ix - 1 - req->start) & (RAW3215_BUFFER_SIZE - 1)) + 1;
	if (len > RAW3215_MAX_BYTES)
		len = RAW3215_MAX_BYTES;
	req->len = len;
	raw->written += len;

	/* set the indication if we should try to enlarge this request */
	req->delayable = (ix == raw->head) && (len < RAW3215_MIN_WRITE);

	ix = req->start;
	while (len > 0) {
		if (ccw > req->ccws)
			ccw[-1].flags |= 0x40; /* use command chaining */
		ccw->cmd_code = 0x01; /* write, auto carrier return */
		ccw->flags = 0x20;    /* ignore incorrect length ind.  */
		ccw->cda =
			(__u32) __pa(raw->buffer + ix);
		count = len;
		if (ix + count > RAW3215_BUFFER_SIZE)
			count = RAW3215_BUFFER_SIZE - ix;
		ccw->count = count;
		len -= count;
		ix = (ix + count) & (RAW3215_BUFFER_SIZE - 1);
		ccw++;
	}
	/*
	 * Add a NOP to the channel program. 3215 devices are purely
	 * emulated and its much better to avoid the channel end
	 * interrupt in this case.
	 */
	if (ccw > req->ccws)
		ccw[-1].flags |= 0x40; /* use command chaining */
	ccw->cmd_code = 0x03; /* NOP */
	ccw->flags = 0;
	ccw->cda = 0;
	ccw->count = 1;
}

/*
 * Start a read or a write request
 */
static void raw3215_start_io(struct raw3215_info *raw)
{
	struct raw3215_req *req;
	int res;

	req = raw->queued_read;
	if (req != NULL &&
	    !(raw->flags & (RAW3215_WORKING | RAW3215_THROTTLED))) {
		/* dequeue request */
		raw->queued_read = NULL;
		res = ccw_device_start(raw->cdev, req->ccws,
				       (unsigned long) req, 0, 0);
		if (res != 0) {
			/* do_IO failed, put request back to queue */
			raw->queued_read = req;
		} else {
			raw->flags |= RAW3215_WORKING;
		}
	}
	req = raw->queued_write;
	if (req != NULL &&
	    !(raw->flags & (RAW3215_WORKING | RAW3215_STOPPED))) {
		/* dequeue request */
		raw->queued_write = NULL;
		res = ccw_device_start(raw->cdev, req->ccws,
				       (unsigned long) req, 0, 0);
		if (res != 0) {
			/* do_IO failed, put request back to queue */
			raw->queued_write = req;
		} else {
			raw->flags |= RAW3215_WORKING;
		}
	}
}

/*
 * Function to start a delayed output after RAW3215_TIMEOUT seconds
 */
static void raw3215_timeout(unsigned long __data)
{
	struct raw3215_info *raw = (struct raw3215_info *) __data;
	unsigned long flags;

	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
	raw->flags &= ~RAW3215_TIMER_RUNS;
	if (!(raw->port.flags & ASYNC_SUSPENDED)) {
		raw3215_mk_write_req(raw);
		raw3215_start_io(raw);
		if ((raw->queued_read || raw->queued_write) &&
		    !(raw->flags & RAW3215_WORKING) &&
		    !(raw->flags & RAW3215_TIMER_RUNS)) {
			raw->timer.expires = RAW3215_TIMEOUT + jiffies;
			add_timer(&raw->timer);
			raw->flags |= RAW3215_TIMER_RUNS;
		}
	}
	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

/*
 * Function to conditionally start an IO. A read is started immediately,
 * a write is only started immediately if the flush flag is on or the
 * amount of data is bigger than RAW3215_MIN_WRITE. If a write is not
 * done immediately a timer is started with a delay of RAW3215_TIMEOUT.
 */
static inline void raw3215_try_io(struct raw3215_info *raw)
{
	if (!(raw->port.flags & ASYNC_INITIALIZED) ||
			(raw->port.flags & ASYNC_SUSPENDED))
		return;
	if (raw->queued_read != NULL)
		raw3215_start_io(raw);
	else if (raw->queued_write != NULL) {
		if ((raw->queued_write->delayable == 0) ||
		    (raw->flags & RAW3215_FLUSHING)) {
			/* execute write requests bigger than minimum size */
			raw3215_start_io(raw);
		}
	}
	if ((raw->queued_read || raw->queued_write) &&
	    !(raw->flags & RAW3215_WORKING) &&
	    !(raw->flags & RAW3215_TIMER_RUNS)) {
		raw->timer.expires = RAW3215_TIMEOUT + jiffies;
		add_timer(&raw->timer);
		raw->flags |= RAW3215_TIMER_RUNS;
	}
}

/*
 * Call tty_wakeup from tasklet context
 */
static void raw3215_wakeup(unsigned long data)
{
	struct raw3215_info *raw = (struct raw3215_info *) data;
	struct tty_struct *tty;

	tty = tty_port_tty_get(&raw->port);
	if (tty) {
		tty_wakeup(tty);
		tty_kref_put(tty);
	}
}

/*
 * Try to start the next IO and wake up processes waiting on the tty.
 */
static void raw3215_next_io(struct raw3215_info *raw, struct tty_struct *tty)
{
	raw3215_mk_write_req(raw);
	raw3215_try_io(raw);
	if (tty && RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE)
		tasklet_schedule(&raw->tlet);
}

/*
 * Interrupt routine, called from common io layer
 */
static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,
			struct irb *irb)
{
	struct raw3215_info *raw;
	struct raw3215_req *req;
	struct tty_struct *tty;
	int cstat, dstat;
	int count;

	raw = dev_get_drvdata(&cdev->dev);
	req = (struct raw3215_req *) intparm;
	tty = tty_port_tty_get(&raw->port);
	cstat = irb->scsw.cmd.cstat;
	dstat = irb->scsw.cmd.dstat;
	if (cstat != 0)
		raw3215_next_io(raw, tty);
	if (dstat & 0x01) { /* we got a unit exception */
		dstat &= ~0x01;	 /* we can ignore it */
	}
	switch (dstat) {
	case 0x80:
		if (cstat != 0)
			break;
		/* Attention interrupt, someone hit the enter key */
		raw3215_mk_read_req(raw);
		raw3215_next_io(raw, tty);
		break;
	case 0x08:
	case 0x0C:
		/* Channel end interrupt. */
		if ((raw = req->info) == NULL)
			goto put_tty;	     /* That shouldn't happen ... */
		if (req->type == RAW3215_READ) {
			/* store residual count, then wait for device end */
			req->residual = irb->scsw.cmd.count;
		}
		if (dstat == 0x08)
			break;
	case 0x04:
		/* Device end interrupt. */
		if ((raw = req->info) == NULL)
			goto put_tty;	     /* That shouldn't happen ... */
		if (req->type == RAW3215_READ && tty != NULL) {
			unsigned int cchar;

			count = 160 - req->residual;
			EBCASC(raw->inbuf, count);
			cchar = ctrlchar_handle(raw->inbuf, count, tty);
			switch (cchar & CTRLCHAR_MASK) {
			case CTRLCHAR_SYSRQ:
				break;

			case CTRLCHAR_CTRL:
				tty_insert_flip_char(&raw->port, cchar,
						TTY_NORMAL);
				tty_flip_buffer_push(&raw->port);
				break;

			case CTRLCHAR_NONE:
				if (count < 2 ||
				    (strncmp(raw->inbuf+count-2, "\252n", 2) &&
				     strncmp(raw->inbuf+count-2, "^n", 2)) ) {
					/* add the auto \n */
					raw->inbuf[count] = '\n';
					count++;
				} else
					count -= 2;
				tty_insert_flip_string(&raw->port, raw->inbuf,
						count);
				tty_flip_buffer_push(&raw->port);
				break;
			}
		} else if (req->type == RAW3215_WRITE) {
			raw->count -= req->len;
			raw->written -= req->len;
		}
		raw->flags &= ~RAW3215_WORKING;
		raw3215_free_req(req);
		/* check for empty wait */
		if (waitqueue_active(&raw->empty_wait) &&
		    raw->queued_write == NULL &&
		    raw->queued_read == NULL) {
			wake_up_interruptible(&raw->empty_wait);
		}
		raw3215_next_io(raw, tty);
		break;
	default:
		/* Strange interrupt, I'll do my best to clean up */
		if (req != NULL && req->type != RAW3215_FREE) {
			if (req->type == RAW3215_WRITE) {
				raw->count -= req->len;
				raw->written -= req->len;
			}
			raw->flags &= ~RAW3215_WORKING;
			raw3215_free_req(req);
		}
		raw3215_next_io(raw, tty);
	}
put_tty:
	tty_kref_put(tty);
}

/*
 * Drop the oldest line from the output buffer.
 */
static void raw3215_drop_line(struct raw3215_info *raw)
{
	int ix;
	char ch;

	BUG_ON(raw->written != 0);
	ix = (raw->head - raw->count) & (RAW3215_BUFFER_SIZE - 1);
	while (raw->count > 0) {
		ch = raw->buffer[ix];
		ix = (ix + 1) & (RAW3215_BUFFER_SIZE - 1);
		raw->count--;
		if (ch == 0x15)
			break;
	}
	raw->head = ix;
}

/*
 * Wait until length bytes are available int the output buffer.
 * Has to be called with the s390irq lock held. Can be called
 * disabled.
 */
static void raw3215_make_room(struct raw3215_info *raw, unsigned int length)
{
	while (RAW3215_BUFFER_SIZE - raw->count < length) {
		/* While console is frozen for suspend we have no other
		 * choice but to drop message from the buffer to make
		 * room for even more messages. */
		if (raw->port.flags & ASYNC_SUSPENDED) {
			raw3215_drop_line(raw);
			continue;
		}
		/* there might be a request pending */
		raw->flags |= RAW3215_FLUSHING;
		raw3215_mk_write_req(raw);
		raw3215_try_io(raw);
		raw->flags &= ~RAW3215_FLUSHING;
#ifdef CONFIG_TN3215_CONSOLE
		ccw_device_wait_idle(raw->cdev);
#endif
		/* Enough room freed up ? */
		if (RAW3215_BUFFER_SIZE - raw->count >= length)
			break;
		/* there might be another cpu waiting for the lock */
		spin_unlock(get_ccwdev_lock(raw->cdev));
		udelay(100);
		spin_lock(get_ccwdev_lock(raw->cdev));
	}
}

/*
 * String write routine for 3215 devices
 */
static void raw3215_write(struct raw3215_info *raw, const char *str,
			  unsigned int length)
{
	unsigned long flags;
	int c, count;

	while (length > 0) {
		spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
		count = (length > RAW3215_BUFFER_SIZE) ?
					     RAW3215_BUFFER_SIZE : length;
		length -= count;

		raw3215_make_room(raw, count);

		/* copy string to output buffer and convert it to EBCDIC */
		while (1) {
			c = min_t(int, count,
				  min(RAW3215_BUFFER_SIZE - raw->count,
				      RAW3215_BUFFER_SIZE - raw->head));
			if (c <= 0)
				break;
			memcpy(raw->buffer + raw->head, str, c);
			ASCEBC(raw->buffer + raw->head, c);
			raw->head = (raw->head + c) & (RAW3215_BUFFER_SIZE - 1);
			raw->count += c;
			raw->line_pos += c;
			str += c;
			count -= c;
		}
		if (!(raw->flags & RAW3215_WORKING)) {
			raw3215_mk_write_req(raw);
			/* start or queue request */
			raw3215_try_io(raw);
		}
		spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
	}
}

/*
 * Put character routine for 3215 devices
 */
static void raw3215_putchar(struct raw3215_info *raw, unsigned char ch)
{
	unsigned long flags;
	unsigned int length, i;

	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
	if (ch == '\t') {
		length = TAB_STOP_SIZE - (raw->line_pos%TAB_STOP_SIZE);
		raw->line_pos += length;
		ch = ' ';
	} else if (ch == '\n') {
		length = 1;
		raw->line_pos = 0;
	} else {
		length = 1;
		raw->line_pos++;
	}
	raw3215_make_room(raw, length);

	for (i = 0; i < length; i++) {
		raw->buffer[raw->head] = (char) _ascebc[(int) ch];
		raw->head = (raw->head + 1) & (RAW3215_BUFFER_SIZE - 1);
		raw->count++;
	}
	if (!(raw->flags & RAW3215_WORKING)) {
		raw3215_mk_write_req(raw);
		/* start or queue request */
		raw3215_try_io(raw);
	}
	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

/*
 * Flush routine, it simply sets the flush flag and tries to start
 * pending IO.
 */
static void raw3215_flush_buffer(struct raw3215_info *raw)
{
	unsigned long flags;

	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
	if (raw->count > 0) {
		raw->flags |= RAW3215_FLUSHING;
		raw3215_try_io(raw);
		raw->flags &= ~RAW3215_FLUSHING;
	}
	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

/*
 * Fire up a 3215 device.
 */
static int raw3215_startup(struct raw3215_info *raw)
{
	unsigned long flags;

	if (raw->port.flags & ASYNC_INITIALIZED)
		return 0;
	raw->line_pos = 0;
	raw->port.flags |= ASYNC_INITIALIZED;
	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
	raw3215_try_io(raw);
	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);

	return 0;
}

/*
 * Shutdown a 3215 device.
 */
static void raw3215_shutdown(struct raw3215_info *raw)
{
	DECLARE_WAITQUEUE(wait, current);
	unsigned long flags;

	if (!(raw->port.flags & ASYNC_INITIALIZED) ||
	    (raw->flags & RAW3215_FIXED))
		return;
	/* Wait for outstanding requests, then free irq */
	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
	if ((raw->flags & RAW3215_WORKING) ||
	    raw->queued_write != NULL ||
	    raw->queued_read != NULL) {
		raw->port.flags |= ASYNC_CLOSING;
		add_wait_queue(&raw->empty_wait, &wait);
		set_current_state(TASK_INTERRUPTIBLE);
		spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
		schedule();
		spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
		remove_wait_queue(&raw->empty_wait, &wait);
		set_current_state(TASK_RUNNING);
		raw->port.flags &= ~(ASYNC_INITIALIZED | ASYNC_CLOSING);
	}
	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

static struct raw3215_info *raw3215_alloc_info(void)
{
	struct raw3215_info *info;

	info = kzalloc(sizeof(struct raw3215_info), GFP_KERNEL | GFP_DMA);
	if (!info)
		return NULL;

	info->buffer = kzalloc(RAW3215_BUFFER_SIZE, GFP_KERNEL | GFP_DMA);
	info->inbuf = kzalloc(RAW3215_INBUF_SIZE, GFP_KERNEL | GFP_DMA);
	if (!info->buffer || !info->inbuf) {
		kfree(info->inbuf);
		kfree(info->buffer);
		kfree(info);
		return NULL;
	}

	setup_timer(&info->timer, raw3215_timeout, (unsigned long)info);
	init_waitqueue_head(&info->empty_wait);
	tasklet_init(&info->tlet, raw3215_wakeup, (unsigned long)info);
	tty_port_init(&info->port);

	return info;
}

static void raw3215_free_info(struct raw3215_info *raw)
{
	kfree(raw->inbuf);
	kfree(raw->buffer);
	tty_port_destroy(&raw->port);
	kfree(raw);
}

static int raw3215_probe (struct ccw_device *cdev)
{
	struct raw3215_info *raw;
	int line;

	/* Console is special. */
	if (raw3215[0] && (raw3215[0] == dev_get_drvdata(&cdev->dev)))
		return 0;

	raw = raw3215_alloc_info();
	if (raw == NULL)
		return -ENOMEM;

	raw->cdev = cdev;
	dev_set_drvdata(&cdev->dev, raw);
	cdev->handler = raw3215_irq;

	spin_lock(&raw3215_device_lock);
	for (line = 0; line < NR_3215; line++) {
		if (!raw3215[line]) {
			raw3215[line] = raw;
			break;
		}
	}
	spin_unlock(&raw3215_device_lock);
	if (line == NR_3215) {
		raw3215_free_info(raw);
		return -ENODEV;
	}

	return 0;
}

static void raw3215_remove (struct ccw_device *cdev)
{
	struct raw3215_info *raw;
	unsigned int line;

	ccw_device_set_offline(cdev);
	raw = dev_get_drvdata(&cdev->dev);
	if (raw) {
		spin_lock(&raw3215_device_lock);
		for (line = 0; line < NR_3215; line++)
			if (raw3215[line] == raw)
				break;
		raw3215[line] = NULL;
		spin_unlock(&raw3215_device_lock);
		dev_set_drvdata(&cdev->dev, NULL);
		raw3215_free_info(raw);
	}
}

static int raw3215_set_online (struct ccw_device *cdev)
{
	struct raw3215_info *raw;

	raw = dev_get_drvdata(&cdev->dev);
	if (!raw)
		return -ENODEV;

	return raw3215_startup(raw);
}

static int raw3215_set_offline (struct ccw_device *cdev)
{
	struct raw3215_info *raw;

	raw = dev_get_drvdata(&cdev->dev);
	if (!raw)
		return -ENODEV;

	raw3215_shutdown(raw);

	return 0;
}

static int raw3215_pm_stop(struct ccw_device *cdev)
{
	struct raw3215_info *raw;
	unsigned long flags;

	/* Empty the output buffer, then prevent new I/O. */
	raw = dev_get_drvdata(&cdev->dev);
	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
	raw3215_make_room(raw, RAW3215_BUFFER_SIZE);
	raw->port.flags |= ASYNC_SUSPENDED;
	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
	return 0;
}

static int raw3215_pm_start(struct ccw_device *cdev)
{
	struct raw3215_info *raw;
	unsigned long flags;

	/* Allow I/O again and flush output buffer. */
	raw = dev_get_drvdata(&cdev->dev);
	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
	raw->port.flags &= ~ASYNC_SUSPENDED;
	raw->flags |= RAW3215_FLUSHING;
	raw3215_try_io(raw);
	raw->flags &= ~RAW3215_FLUSHING;
	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
	return 0;
}

static struct ccw_device_id raw3215_id[] = {
	{ CCW_DEVICE(0x3215, 0) },
	{ /* end of list */ },
};

static struct ccw_driver raw3215_ccw_driver = {
	.driver = {
		.name	= "3215",
		.owner	= THIS_MODULE,
	},
	.ids		= raw3215_id,
	.probe		= &raw3215_probe,
	.remove		= &raw3215_remove,
	.set_online	= &raw3215_set_online,
	.set_offline	= &raw3215_set_offline,
	.freeze		= &raw3215_pm_stop,
	.thaw		= &raw3215_pm_start,
	.restore	= &raw3215_pm_start,
	.int_class	= IRQIO_C15,
};

#ifdef CONFIG_TN3215_CONSOLE
/*
 * Write a string to the 3215 console
 */
static void con3215_write(struct console *co, const char *str,
			  unsigned int count)
{
	struct raw3215_info *raw;
	int i;

	if (count <= 0)
		return;
	raw = raw3215[0];	/* console 3215 is the first one */
	while (count > 0) {
		for (i = 0; i < count; i++)
			if (str[i] == '\t' || str[i] == '\n')
				break;
		raw3215_write(raw, str, i);
		count -= i;
		str += i;
		if (count > 0) {
			raw3215_putchar(raw, *str);
			count--;
			str++;
		}
	}
}

static struct tty_driver *con3215_device(struct console *c, int *index)
{
	*index = c->index;
	return tty3215_driver;
}

/*
 * panic() calls con3215_flush through a panic_notifier
 * before the system enters a disabled, endless loop.
 */
static void con3215_flush(void)
{
	struct raw3215_info *raw;
	unsigned long flags;

	raw = raw3215[0];  /* console 3215 is the first one */
	if (raw->port.flags & ASYNC_SUSPENDED)
		/* The console is still frozen for suspend. */
		if (ccw_device_force_console(raw->cdev))
			/* Forcing didn't work, no panic message .. */
			return;
	spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
	raw3215_make_room(raw, RAW3215_BUFFER_SIZE);
	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
}

static int con3215_notify(struct notifier_block *self,
			  unsigned long event, void *data)
{
	con3215_flush();
	return NOTIFY_OK;
}

static struct notifier_block on_panic_nb = {
	.notifier_call = con3215_notify,
	.priority = 0,
};

static struct notifier_block on_reboot_nb = {
	.notifier_call = con3215_notify,
	.priority = 0,
};

/*
 *  The console structure for the 3215 console
 */
static struct console con3215 = {
	.name	 = "ttyS",
	.write	 = con3215_write,
	.device	 = con3215_device,
	.flags	 = CON_PRINTBUFFER,
};

/*
 * 3215 console initialization code called from console_init().
 */
static int __init con3215_init(void)
{
	struct ccw_device *cdev;
	struct raw3215_info *raw;
	struct raw3215_req *req;
	int i;

	/* Check if 3215 is to be the console */
	if (!CONSOLE_IS_3215)
		return -ENODEV;

	/* Set the console mode for VM */
	if (MACHINE_IS_VM) {
		cpcmd("TERM CONMODE 3215", NULL, 0, NULL);
		cpcmd("TERM AUTOCR OFF", NULL, 0, NULL);
	}

	/* allocate 3215 request structures */
	raw3215_freelist = NULL;
	spin_lock_init(&raw3215_freelist_lock);
	for (i = 0; i < NR_3215_REQ; i++) {
		req = kzalloc(sizeof(struct raw3215_req), GFP_KERNEL | GFP_DMA);
		req->next = raw3215_freelist;
		raw3215_freelist = req;
	}

	cdev = ccw_device_create_console(&raw3215_ccw_driver);
	if (IS_ERR(cdev))
		return -ENODEV;

	raw3215[0] = raw = raw3215_alloc_info();
	raw->cdev = cdev;
	dev_set_drvdata(&cdev->dev, raw);
	cdev->handler = raw3215_irq;

	raw->flags |= RAW3215_FIXED;
	if (ccw_device_enable_console(cdev)) {
		ccw_device_destroy_console(cdev);
		raw3215_free_info(raw);
		raw3215[0] = NULL;
		return -ENODEV;
	}

	/* Request the console irq */
	if (raw3215_startup(raw) != 0) {
		raw3215_free_info(raw);
		raw3215[0] = NULL;
		return -ENODEV;
	}
	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
	register_reboot_notifier(&on_reboot_nb);
	register_console(&con3215);
	return 0;
}
console_initcall(con3215_init);
#endif

static int tty3215_install(struct tty_driver *driver, struct tty_struct *tty)
{
	struct raw3215_info *raw;

	raw = raw3215[tty->index];
	if (raw == NULL)
		return -ENODEV;

	tty->driver_data = raw;

	return tty_port_install(&raw->port, driver, tty);
}

/*
 * tty3215_open
 *
 * This routine is called whenever a 3215 tty is opened.
 */
static int tty3215_open(struct tty_struct *tty, struct file * filp)
{
	struct raw3215_info *raw = tty->driver_data;
	int retval;

	tty_port_tty_set(&raw->port, tty);

	raw->port.low_latency = 0; /* don't use bottom half for pushing chars */
	/*
	 * Start up 3215 device
	 */
	retval = raw3215_startup(raw);
	if (retval)
		return retval;

	return 0;
}

/*
 * tty3215_close()
 *
 * This routine is called when the 3215 tty is closed. We wait
 * for the remaining request to be completed. Then we clean up.
 */
static void tty3215_close(struct tty_struct *tty, struct file * filp)
{
	struct raw3215_info *raw;

	raw = (struct raw3215_info *) tty->driver_data;
	if (raw == NULL || tty->count > 1)
		return;
	tty->closing = 1;
	/* Shutdown the terminal */
	raw3215_shutdown(raw);
	tasklet_kill(&raw->tlet);
	tty->closing = 0;
	tty_port_tty_set(&raw->port, NULL);
}

/*
 * Returns the amount of free space in the output buffer.
 */
static int tty3215_write_room(struct tty_struct *tty)
{
	struct raw3215_info *raw;

	raw = (struct raw3215_info *) tty->driver_data;

	/* Subtract TAB_STOP_SIZE to allow for a tab, 8 <<< 64K */
	if ((RAW3215_BUFFER_SIZE - raw->count - TAB_STOP_SIZE) >= 0)
		return RAW3215_BUFFER_SIZE - raw->count - TAB_STOP_SIZE;
	else
		return 0;
}

/*
 * String write routine for 3215 ttys
 */
static int tty3215_write(struct tty_struct * tty,
			 const unsigned char *buf, int count)
{
	struct raw3215_info *raw;
	int i, written;

	if (!tty)
		return 0;
	raw = (struct raw3215_info *) tty->driver_data;
	written = count;
	while (count > 0) {
		for (i = 0; i < count; i++)
			if (buf[i] == '\t' || buf[i] == '\n')
				break;
		raw3215_write(raw, buf, i);
		count -= i;
		buf += i;
		if (count > 0) {
			raw3215_putchar(raw, *buf);
			count--;
			buf++;
		}
	}
	return written;
}

/*
 * Put character routine for 3215 ttys
 */
static int tty3215_put_char(struct tty_struct *tty, unsigned char ch)
{
	struct raw3215_info *raw;

	if (!tty)
		return 0;
	raw = (struct raw3215_info *) tty->driver_data;
	raw3215_putchar(raw, ch);
	return 1;
}

static void tty3215_flush_chars(struct tty_struct *tty)
{
}

/*
 * Returns the number of characters in the output buffer
 */
static int tty3215_chars_in_buffer(struct tty_struct *tty)
{
	struct raw3215_info *raw;

	raw = (struct raw3215_info *) tty->driver_data;
	return raw->count;
}

static void tty3215_flush_buffer(struct tty_struct *tty)
{
	struct raw3215_info *raw;

	raw = (struct raw3215_info *) tty->driver_data;
	raw3215_flush_buffer(raw);
	tty_wakeup(tty);
}

/*
 * Disable reading from a 3215 tty
 */
static void tty3215_throttle(struct tty_struct * tty)
{
	struct raw3215_info *raw;

	raw = (struct raw3215_info *) tty->driver_data;
	raw->flags |= RAW3215_THROTTLED;
}

/*
 * Enable reading from a 3215 tty
 */
static void tty3215_unthrottle(struct tty_struct * tty)
{
	struct raw3215_info *raw;
	unsigned long flags;

	raw = (struct raw3215_info *) tty->driver_data;
	if (raw->flags & RAW3215_THROTTLED) {
		spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
		raw->flags &= ~RAW3215_THROTTLED;
		raw3215_try_io(raw);
		spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
	}
}

/*
 * Disable writing to a 3215 tty
 */
static void tty3215_stop(struct tty_struct *tty)
{
	struct raw3215_info *raw;

	raw = (struct raw3215_info *) tty->driver_data;
	raw->flags |= RAW3215_STOPPED;
}

/*
 * Enable writing to a 3215 tty
 */
static void tty3215_start(struct tty_struct *tty)
{
	struct raw3215_info *raw;
	unsigned long flags;

	raw = (struct raw3215_info *) tty->driver_data;
	if (raw->flags & RAW3215_STOPPED) {
		spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
		raw->flags &= ~RAW3215_STOPPED;
		raw3215_try_io(raw);
		spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
	}
}

static const struct tty_operations tty3215_ops = {
	.install = tty3215_install,
	.open = tty3215_open,
	.close = tty3215_close,
	.write = tty3215_write,
	.put_char = tty3215_put_char,
	.flush_chars = tty3215_flush_chars,
	.write_room = tty3215_write_room,
	.chars_in_buffer = tty3215_chars_in_buffer,
	.flush_buffer = tty3215_flush_buffer,
	.throttle = tty3215_throttle,
	.unthrottle = tty3215_unthrottle,
	.stop = tty3215_stop,
	.start = tty3215_start,
};

/*
 * 3215 tty registration code called from tty_init().
 * Most kernel services (incl. kmalloc) are available at this poimt.
 */
static int __init tty3215_init(void)
{
	struct tty_driver *driver;
	int ret;

	if (!CONSOLE_IS_3215)
		return 0;

	driver = alloc_tty_driver(NR_3215);
	if (!driver)
		return -ENOMEM;

	ret = ccw_driver_register(&raw3215_ccw_driver);
	if (ret) {
		put_tty_driver(driver);
		return ret;
	}
	/*
	 * Initialize the tty_driver structure
	 * Entries in tty3215_driver that are NOT initialized:
	 * proc_entry, set_termios, flush_buffer, set_ldisc, write_proc
	 */

	driver->driver_name = "tty3215";
	driver->name = "ttyS";
	driver->major = TTY_MAJOR;
	driver->minor_start = 64;
	driver->type = TTY_DRIVER_TYPE_SYSTEM;
	driver->subtype = SYSTEM_TYPE_TTY;
	driver->init_termios = tty_std_termios;
	driver->init_termios.c_iflag = IGNBRK | IGNPAR;
	driver->init_termios.c_oflag = ONLCR;
	driver->init_termios.c_lflag = ISIG;
	driver->flags = TTY_DRIVER_REAL_RAW;
	tty_set_operations(driver, &tty3215_ops);
	ret = tty_register_driver(driver);
	if (ret) {
		put_tty_driver(driver);
		return ret;
	}
	tty3215_driver = driver;
	return 0;
}

static void __exit tty3215_exit(void)
{
	tty_unregister_driver(tty3215_driver);
	put_tty_driver(tty3215_driver);
	ccw_driver_unregister(&raw3215_ccw_driver);
}

module_init(tty3215_init);
module_exit(tty3215_exit);