aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/s390/char/sclp_tty.c
blob: 90536f60bf502f0410c13607d0b0555c494ae374 (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
/*
 *  drivers/s390/char/sclp_tty.c
 *    SCLP line mode terminal driver.
 *
 *  S390 version
 *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Peschke <mpeschke@de.ibm.com>
 *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#include <linux/module.h>
#include <linux/kmod.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>

#include "ctrlchar.h"
#include "sclp.h"
#include "sclp_rw.h"
#include "sclp_tty.h"

#define SCLP_TTY_PRINT_HEADER "sclp tty driver: "

/*
 * size of a buffer that collects single characters coming in
 * via sclp_tty_put_char()
 */
#define SCLP_TTY_BUF_SIZE 512

/*
 * There is exactly one SCLP terminal, so we can keep things simple
 * and allocate all variables statically.
 */

/* Lock to guard over changes to global variables. */
static spinlock_t sclp_tty_lock;
/* List of free pages that can be used for console output buffering. */
static struct list_head sclp_tty_pages;
/* List of full struct sclp_buffer structures ready for output. */
static struct list_head sclp_tty_outqueue;
/* Counter how many buffers are emitted. */
static int sclp_tty_buffer_count;
/* Pointer to current console buffer. */
static struct sclp_buffer *sclp_ttybuf;
/* Timer for delayed output of console messages. */
static struct timer_list sclp_tty_timer;
/* Waitqueue to wait for buffers to get empty. */
static wait_queue_head_t sclp_tty_waitq;

static struct tty_struct *sclp_tty;
static unsigned char sclp_tty_chars[SCLP_TTY_BUF_SIZE];
static unsigned short int sclp_tty_chars_count;

struct tty_driver *sclp_tty_driver;

static struct sclp_ioctls sclp_ioctls;
static struct sclp_ioctls sclp_ioctls_init =
{
	8,			/* 1 hor. tab. = 8 spaces */
	0,			/* no echo of input by this driver */
	80,			/* 80 characters/line */
	1,			/* write after 1/10 s without final new line */
	MAX_KMEM_PAGES,		/* quick fix: avoid __alloc_pages */
	MAX_KMEM_PAGES,		/* take 32/64 pages from kernel memory, */
	0,			/* do not convert to lower case */
	0x6c			/* to seprate upper and lower case */
				/* ('%' in EBCDIC) */
};

/* This routine is called whenever we try to open a SCLP terminal. */
static int
sclp_tty_open(struct tty_struct *tty, struct file *filp)
{
	sclp_tty = tty;
	tty->driver_data = NULL;
	tty->low_latency = 0;
	return 0;
}

/* This routine is called when the SCLP terminal is closed. */
static void
sclp_tty_close(struct tty_struct *tty, struct file *filp)
{
	if (tty->count > 1)
		return;
	sclp_tty = NULL;
}

/* execute commands to control the i/o behaviour of the SCLP tty at runtime */
static int
sclp_tty_ioctl(struct tty_struct *tty, struct file * file,
	       unsigned int cmd, unsigned long arg)
{
	unsigned long flags;
	unsigned int obuf;
	int check;
	int rc;

	if (tty->flags & (1 << TTY_IO_ERROR))
		return -EIO;
	rc = 0;
	check = 0;
	switch (cmd) {
	case TIOCSCLPSHTAB:
		/* set width of horizontal tab	*/
		if (get_user(sclp_ioctls.htab, (unsigned short __user *) arg))
			rc = -EFAULT;
		else
			check = 1;
		break;
	case TIOCSCLPGHTAB:
		/* get width of horizontal tab	*/
		if (put_user(sclp_ioctls.htab, (unsigned short __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPSECHO:
		/* enable/disable echo of input */
		if (get_user(sclp_ioctls.echo, (unsigned char __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPGECHO:
		/* Is echo of input enabled ?  */
		if (put_user(sclp_ioctls.echo, (unsigned char __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPSCOLS:
		/* set number of columns for output  */
		if (get_user(sclp_ioctls.columns, (unsigned short __user *) arg))
			rc = -EFAULT;
		else
			check = 1;
		break;
	case TIOCSCLPGCOLS:
		/* get number of columns for output  */
		if (put_user(sclp_ioctls.columns, (unsigned short __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPSNL:
		/* enable/disable writing without final new line character  */
		if (get_user(sclp_ioctls.final_nl, (signed char __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPGNL:
		/* Is writing without final new line character enabled ?  */
		if (put_user(sclp_ioctls.final_nl, (signed char __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPSOBUF:
		/*
		 * set the maximum buffers size for output, will be rounded
		 * up to next 4kB boundary and stored as number of SCCBs
		 * (4kB Buffers) limitation: 256 x 4kB
		 */
		if (get_user(obuf, (unsigned int __user *) arg) == 0) {
			if (obuf & 0xFFF)
				sclp_ioctls.max_sccb = (obuf >> 12) + 1;
			else
				sclp_ioctls.max_sccb = (obuf >> 12);
		} else
			rc = -EFAULT;
		break;
	case TIOCSCLPGOBUF:
		/* get the maximum buffers size for output  */
		obuf = sclp_ioctls.max_sccb << 12;
		if (put_user(obuf, (unsigned int __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPGKBUF:
		/* get the number of buffers got from kernel at startup */
		if (put_user(sclp_ioctls.kmem_sccb, (unsigned short __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPSCASE:
		/* enable/disable conversion from upper to lower case */
		if (get_user(sclp_ioctls.tolower, (unsigned char __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPGCASE:
		/* Is conversion from upper to lower case of input enabled? */
		if (put_user(sclp_ioctls.tolower, (unsigned char __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPSDELIM:
		/*
		 * set special character used for separating upper and
		 * lower case, 0x00 disables this feature
		 */
		if (get_user(sclp_ioctls.delim, (unsigned char __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPGDELIM:
		/*
		 * get special character used for separating upper and
		 * lower case, 0x00 disables this feature
		 */
		if (put_user(sclp_ioctls.delim, (unsigned char __user *) arg))
			rc = -EFAULT;
		break;
	case TIOCSCLPSINIT:
		/* set initial (default) sclp ioctls  */
		sclp_ioctls = sclp_ioctls_init;
		check = 1;
		break;
	default:
		rc = -ENOIOCTLCMD;
		break;
	}
	if (check) {
		spin_lock_irqsave(&sclp_tty_lock, flags);
		if (sclp_ttybuf != NULL) {
			sclp_set_htab(sclp_ttybuf, sclp_ioctls.htab);
			sclp_set_columns(sclp_ttybuf, sclp_ioctls.columns);
		}
		spin_unlock_irqrestore(&sclp_tty_lock, flags);
	}
	return rc;
}

/*
 * This routine returns the numbers of characters the tty driver
 * will accept for queuing to be written.  This number is subject
 * to change as output buffers get emptied, or if the output flow
 * control is acted. This is not an exact number because not every
 * character needs the same space in the sccb. The worst case is
 * a string of newlines. Every newlines creates a new mto which
 * needs 8 bytes.
 */
static int
sclp_tty_write_room (struct tty_struct *tty)
{
	unsigned long flags;
	struct list_head *l;
	int count;

	spin_lock_irqsave(&sclp_tty_lock, flags);
	count = 0;
	if (sclp_ttybuf != NULL)
		count = sclp_buffer_space(sclp_ttybuf) / sizeof(struct mto);
	list_for_each(l, &sclp_tty_pages)
		count += NR_EMPTY_MTO_PER_SCCB;
	spin_unlock_irqrestore(&sclp_tty_lock, flags);
	return count;
}

static void
sclp_ttybuf_callback(struct sclp_buffer *buffer, int rc)
{
	unsigned long flags;
	void *page;

	do {
		page = sclp_unmake_buffer(buffer);
		spin_lock_irqsave(&sclp_tty_lock, flags);
		/* Remove buffer from outqueue */
		list_del(&buffer->list);
		sclp_tty_buffer_count--;
		list_add_tail((struct list_head *) page, &sclp_tty_pages);
		/* Check if there is a pending buffer on the out queue. */
		buffer = NULL;
		if (!list_empty(&sclp_tty_outqueue))
			buffer = list_entry(sclp_tty_outqueue.next,
					    struct sclp_buffer, list);
		spin_unlock_irqrestore(&sclp_tty_lock, flags);
	} while (buffer && sclp_emit_buffer(buffer, sclp_ttybuf_callback));
	wake_up(&sclp_tty_waitq);
	/* check if the tty needs a wake up call */
	if (sclp_tty != NULL) {
		tty_wakeup(sclp_tty);
	}
}

static inline void
__sclp_ttybuf_emit(struct sclp_buffer *buffer)
{
	unsigned long flags;
	int count;
	int rc;

	spin_lock_irqsave(&sclp_tty_lock, flags);
	list_add_tail(&buffer->list, &sclp_tty_outqueue);
	count = sclp_tty_buffer_count++;
	spin_unlock_irqrestore(&sclp_tty_lock, flags);
	if (count)
		return;
	rc = sclp_emit_buffer(buffer, sclp_ttybuf_callback);
	if (rc)
		sclp_ttybuf_callback(buffer, rc);
}

/*
 * When this routine is called from the timer then we flush the
 * temporary write buffer.
 */
static void
sclp_tty_timeout(unsigned long data)
{
	unsigned long flags;
	struct sclp_buffer *buf;

	spin_lock_irqsave(&sclp_tty_lock, flags);
	buf = sclp_ttybuf;
	sclp_ttybuf = NULL;
	spin_unlock_irqrestore(&sclp_tty_lock, flags);

	if (buf != NULL) {
		__sclp_ttybuf_emit(buf);
	}
}

/*
 * Write a string to the sclp tty.
 */
static void
sclp_tty_write_string(const unsigned char *str, int count)
{
	unsigned long flags;
	void *page;
	int written;
	struct sclp_buffer *buf;

	if (count <= 0)
		return;
	spin_lock_irqsave(&sclp_tty_lock, flags);
	do {
		/* Create a sclp output buffer if none exists yet */
		if (sclp_ttybuf == NULL) {
			while (list_empty(&sclp_tty_pages)) {
				spin_unlock_irqrestore(&sclp_tty_lock, flags);
				if (in_interrupt())
					sclp_sync_wait();
				else
					wait_event(sclp_tty_waitq,
						!list_empty(&sclp_tty_pages));
				spin_lock_irqsave(&sclp_tty_lock, flags);
			}
			page = sclp_tty_pages.next;
			list_del((struct list_head *) page);
			sclp_ttybuf = sclp_make_buffer(page,
						       sclp_ioctls.columns,
						       sclp_ioctls.htab);
		}
		/* try to write the string to the current output buffer */
		written = sclp_write(sclp_ttybuf, str, count);
		if (written == count)
			break;
		/*
		 * Not all characters could be written to the current
		 * output buffer. Emit the buffer, create a new buffer
		 * and then output the rest of the string.
		 */
		buf = sclp_ttybuf;
		sclp_ttybuf = NULL;
		spin_unlock_irqrestore(&sclp_tty_lock, flags);
		__sclp_ttybuf_emit(buf);
		spin_lock_irqsave(&sclp_tty_lock, flags);
		str += written;
		count -= written;
	} while (count > 0);
	/* Setup timer to output current console buffer after 1/10 second */
	if (sclp_ioctls.final_nl) {
		if (sclp_ttybuf != NULL &&
		    sclp_chars_in_buffer(sclp_ttybuf) != 0 &&
		    !timer_pending(&sclp_tty_timer)) {
			init_timer(&sclp_tty_timer);
			sclp_tty_timer.function = sclp_tty_timeout;
			sclp_tty_timer.data = 0UL;
			sclp_tty_timer.expires = jiffies + HZ/10;
			add_timer(&sclp_tty_timer);
		}
	} else {
		if (sclp_ttybuf != NULL &&
		    sclp_chars_in_buffer(sclp_ttybuf) != 0) {
			buf = sclp_ttybuf;
			sclp_ttybuf = NULL;
			spin_unlock_irqrestore(&sclp_tty_lock, flags);
			__sclp_ttybuf_emit(buf);
			spin_lock_irqsave(&sclp_tty_lock, flags);
		}
	}
	spin_unlock_irqrestore(&sclp_tty_lock, flags);
}

/*
 * This routine is called by the kernel to write a series of characters to the
 * tty device. The characters may come from user space or kernel space. This
 * routine will return the number of characters actually accepted for writing.
 */
static int
sclp_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
	if (sclp_tty_chars_count > 0) {
		sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
		sclp_tty_chars_count = 0;
	}
	sclp_tty_write_string(buf, count);
	return count;
}

/*
 * This routine is called by the kernel to write a single character to the tty
 * device. If the kernel uses this routine, it must call the flush_chars()
 * routine (if defined) when it is done stuffing characters into the driver.
 *
 * Characters provided to sclp_tty_put_char() are buffered by the SCLP driver.
 * If the given character is a '\n' the contents of the SCLP write buffer
 * - including previous characters from sclp_tty_put_char() and strings from
 * sclp_write() without final '\n' - will be written.
 */
static void
sclp_tty_put_char(struct tty_struct *tty, unsigned char ch)
{
	sclp_tty_chars[sclp_tty_chars_count++] = ch;
	if (ch == '\n' || sclp_tty_chars_count >= SCLP_TTY_BUF_SIZE) {
		sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
		sclp_tty_chars_count = 0;
	}
}

/*
 * This routine is called by the kernel after it has written a series of
 * characters to the tty device using put_char().
 */
static void
sclp_tty_flush_chars(struct tty_struct *tty)
{
	if (sclp_tty_chars_count > 0) {
		sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
		sclp_tty_chars_count = 0;
	}
}

/*
 * This routine returns the number of characters in the write buffer of the
 * SCLP driver. The provided number includes all characters that are stored
 * in the SCCB (will be written next time the SCLP is not busy) as well as
 * characters in the write buffer (will not be written as long as there is a
 * final line feed missing).
 */
static int
sclp_tty_chars_in_buffer(struct tty_struct *tty)
{
	unsigned long flags;
	struct list_head *l;
	struct sclp_buffer *t;
	int count;

	spin_lock_irqsave(&sclp_tty_lock, flags);
	count = 0;
	if (sclp_ttybuf != NULL)
		count = sclp_chars_in_buffer(sclp_ttybuf);
	list_for_each(l, &sclp_tty_outqueue) {
		t = list_entry(l, struct sclp_buffer, list);
		count += sclp_chars_in_buffer(t);
	}
	spin_unlock_irqrestore(&sclp_tty_lock, flags);
	return count;
}

/*
 * removes all content from buffers of low level driver
 */
static void
sclp_tty_flush_buffer(struct tty_struct *tty)
{
	if (sclp_tty_chars_count > 0) {
		sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
		sclp_tty_chars_count = 0;
	}
}

/*
 * push input to tty
 */
static void
sclp_tty_input(unsigned char* buf, unsigned int count)
{
	unsigned int cchar;

	/*
	 * If this tty driver is currently closed
	 * then throw the received input away.
	 */
	if (sclp_tty == NULL)
		return;
	cchar = ctrlchar_handle(buf, count, sclp_tty);
	switch (cchar & CTRLCHAR_MASK) {
	case CTRLCHAR_SYSRQ:
		break;
	case CTRLCHAR_CTRL:
		tty_insert_flip_char(sclp_tty, cchar, TTY_NORMAL);
		tty_flip_buffer_push(sclp_tty);
		break;
	case CTRLCHAR_NONE:
		/* send (normal) input to line discipline */
		if (count < 2 ||
		    (strncmp((const char *) buf + count - 2, "^n", 2) &&
		     strncmp((const char *) buf + count - 2, "\252n", 2))) {
			/* add the auto \n */
			tty_insert_flip_string(sclp_tty, buf, count);
			tty_insert_flip_char(sclp_tty, '\n', TTY_NORMAL);
		} else
			tty_insert_flip_string(sclp_tty, buf, count - 2);
		tty_flip_buffer_push(sclp_tty);
		break;
	}
}

/*
 * get a EBCDIC string in upper/lower case,
 * find out characters in lower/upper case separated by a special character,
 * modifiy original string,
 * returns length of resulting string
 */
static int
sclp_switch_cases(unsigned char *buf, int count,
		  unsigned char delim, int tolower)
{
	unsigned char *ip, *op;
	int toggle;

	/* initially changing case is off */
	toggle = 0;
	ip = op = buf;
	while (count-- > 0) {
		/* compare with special character */
		if (*ip == delim) {
			/* followed by another special character? */
			if (count && ip[1] == delim) {
				/*
				 * ... then put a single copy of the special
				 * character to the output string
				 */
				*op++ = *ip++;
				count--;
			} else
				/*
				 * ... special character follower by a normal
				 * character toggles the case change behaviour
				 */
				toggle = ~toggle;
			/* skip special character */
			ip++;
		} else
			/* not the special character */
			if (toggle)
				/* but case switching is on */
				if (tolower)
					/* switch to uppercase */
					*op++ = _ebc_toupper[(int) *ip++];
				else
					/* switch to lowercase */
					*op++ = _ebc_tolower[(int) *ip++];
			else
				/* no case switching, copy the character */
				*op++ = *ip++;
	}
	/* return length of reformatted string. */
	return op - buf;
}

static void
sclp_get_input(unsigned char *start, unsigned char *end)
{
	int count;

	count = end - start;
	/*
	 * if set in ioctl convert EBCDIC to lower case
	 * (modify original input in SCCB)
	 */
	if (sclp_ioctls.tolower)
		EBC_TOLOWER(start, count);

	/*
	 * if set in ioctl find out characters in lower or upper case
	 * (depends on current case) separated by a special character,
	 * works on EBCDIC
	 */
	if (sclp_ioctls.delim)
		count = sclp_switch_cases(start, count,
					  sclp_ioctls.delim,
					  sclp_ioctls.tolower);

	/* convert EBCDIC to ASCII (modify original input in SCCB) */
	sclp_ebcasc_str(start, count);

	/* if set in ioctl write operators input to console  */
	if (sclp_ioctls.echo)
		sclp_tty_write(sclp_tty, start, count);

	/* transfer input to high level driver */
	sclp_tty_input(start, count);
}

static inline struct gds_vector *
find_gds_vector(struct gds_vector *start, struct gds_vector *end, u16 id)
{
	struct gds_vector *vec;

	for (vec = start; vec < end; vec = (void *) vec + vec->length)
		if (vec->gds_id == id)
			return vec;
	return NULL;
}

static inline struct gds_subvector *
find_gds_subvector(struct gds_subvector *start,
		   struct gds_subvector *end, u8 key)
{
	struct gds_subvector *subvec;

	for (subvec = start; subvec < end;
	     subvec = (void *) subvec + subvec->length)
		if (subvec->key == key)
			return subvec;
	return NULL;
}

static inline void
sclp_eval_selfdeftextmsg(struct gds_subvector *start,
			 struct gds_subvector *end)
{
	struct gds_subvector *subvec;

	subvec = start;
	while (subvec < end) {
		subvec = find_gds_subvector(subvec, end, 0x30);
		if (!subvec)
			break;
		sclp_get_input((unsigned char *)(subvec + 1),
			       (unsigned char *) subvec + subvec->length);
		subvec = (void *) subvec + subvec->length;
	}
}

static inline void
sclp_eval_textcmd(struct gds_subvector *start,
		  struct gds_subvector *end)
{
	struct gds_subvector *subvec;

	subvec = start;
	while (subvec < end) {
		subvec = find_gds_subvector(subvec, end,
					    GDS_KEY_SelfDefTextMsg);
		if (!subvec)
			break;
		sclp_eval_selfdeftextmsg((struct gds_subvector *)(subvec + 1),
					 (void *)subvec + subvec->length);
		subvec = (void *) subvec + subvec->length;
	}
}

static inline void
sclp_eval_cpmsu(struct gds_vector *start, struct gds_vector *end)
{
	struct gds_vector *vec;

	vec = start;
	while (vec < end) {
		vec = find_gds_vector(vec, end, GDS_ID_TextCmd);
		if (!vec)
			break;
		sclp_eval_textcmd((struct gds_subvector *)(vec + 1),
				  (void *) vec + vec->length);
		vec = (void *) vec + vec->length;
	}
}


static inline void
sclp_eval_mdsmu(struct gds_vector *start, void *end)
{
	struct gds_vector *vec;

	vec = find_gds_vector(start, end, GDS_ID_CPMSU);
	if (vec)
		sclp_eval_cpmsu(vec + 1, (void *) vec + vec->length);
}

static void
sclp_tty_receiver(struct evbuf_header *evbuf)
{
	struct gds_vector *start, *end, *vec;

	start = (struct gds_vector *)(evbuf + 1);
	end = (void *) evbuf + evbuf->length;
	vec = find_gds_vector(start, end, GDS_ID_MDSMU);
	if (vec)
		sclp_eval_mdsmu(vec + 1, (void *) vec + vec->length);
}

static void
sclp_tty_state_change(struct sclp_register *reg)
{
}

static struct sclp_register sclp_input_event =
{
	.receive_mask = EvTyp_OpCmd_Mask | EvTyp_PMsgCmd_Mask,
	.state_change_fn = sclp_tty_state_change,
	.receiver_fn = sclp_tty_receiver
};

static const struct tty_operations sclp_ops = {
	.open = sclp_tty_open,
	.close = sclp_tty_close,
	.write = sclp_tty_write,
	.put_char = sclp_tty_put_char,
	.flush_chars = sclp_tty_flush_chars,
	.write_room = sclp_tty_write_room,
	.chars_in_buffer = sclp_tty_chars_in_buffer,
	.flush_buffer = sclp_tty_flush_buffer,
	.ioctl = sclp_tty_ioctl,
};

static int __init
sclp_tty_init(void)
{
	struct tty_driver *driver;
	void *page;
	int i;
	int rc;

	if (!CONSOLE_IS_SCLP)
		return 0;
	driver = alloc_tty_driver(1);
	if (!driver)
		return -ENOMEM;

	rc = sclp_rw_init();
	if (rc) {
		printk(KERN_ERR SCLP_TTY_PRINT_HEADER
		       "could not register tty - "
		       "sclp_rw_init returned %d\n", rc);
		put_tty_driver(driver);
		return rc;
	}
	/* Allocate pages for output buffering */
	INIT_LIST_HEAD(&sclp_tty_pages);
	for (i = 0; i < MAX_KMEM_PAGES; i++) {
		page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
		if (page == NULL) {
			put_tty_driver(driver);
			return -ENOMEM;
		}
		list_add_tail((struct list_head *) page, &sclp_tty_pages);
	}
	INIT_LIST_HEAD(&sclp_tty_outqueue);
	spin_lock_init(&sclp_tty_lock);
	init_waitqueue_head(&sclp_tty_waitq);
	init_timer(&sclp_tty_timer);
	sclp_ttybuf = NULL;
	sclp_tty_buffer_count = 0;
	if (MACHINE_IS_VM) {
		/*
		 * save 4 characters for the CPU number
		 * written at start of each line by VM/CP
		 */
		sclp_ioctls_init.columns = 76;
		/* case input lines to lowercase */
		sclp_ioctls_init.tolower = 1;
	}
	sclp_ioctls = sclp_ioctls_init;
	sclp_tty_chars_count = 0;
	sclp_tty = NULL;

	rc = sclp_register(&sclp_input_event);
	if (rc) {
		put_tty_driver(driver);
		return rc;
	}

	driver->owner = THIS_MODULE;
	driver->driver_name = "sclp_line";
	driver->name = "sclp_line";
	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 | XTABS;
	driver->init_termios.c_lflag = ISIG | ECHO;
	driver->flags = TTY_DRIVER_REAL_RAW;
	tty_set_operations(driver, &sclp_ops);
	rc = tty_register_driver(driver);
	if (rc) {
		printk(KERN_ERR SCLP_TTY_PRINT_HEADER
		       "could not register tty - "
		       "tty_register_driver returned %d\n", rc);
		put_tty_driver(driver);
		return rc;
	}
	sclp_tty_driver = driver;
	return 0;
}
module_init(sclp_tty_init);