summaryrefslogtreecommitdiffstats
path: root/drivers/s390/char/sclp_tty.c
blob: e66a75b3822cbf24f09c0824c87b7f0c81089749 (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
/*
 *  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/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/gfp.h>
#include <asm/uaccess.h>

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

/*
 * 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;

static struct tty_port sclp_port;
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 int sclp_tty_tolower;
static int sclp_tty_columns = 80;

#define SPACES_PER_TAB 8
#define CASE_DELIMITER 0x6c /* to separate 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)
{
	tty_port_tty_set(&sclp_port, 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;
	tty_port_tty_set(&sclp_port, NULL);
}

/*
 * 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)
{
	struct tty_struct *tty;
	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));
	/* check if the tty needs a wake up call */
	tty = tty_port_tty_get(&sclp_port);
	if (tty != NULL) {
		tty_wakeup(tty);
		tty_kref_put(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 int sclp_tty_write_string(const unsigned char *str, int count, int may_fail)
{
	unsigned long flags;
	void *page;
	int written;
	int overall_written;
	struct sclp_buffer *buf;

	if (count <= 0)
		return 0;
	overall_written = 0;
	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 (may_fail)
					goto out;
				else
					sclp_sync_wait();
				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_tty_columns,
						       SPACES_PER_TAB);
		}
		/* try to write the string to the current output buffer */
		written = sclp_write(sclp_ttybuf, str, count);
		overall_written += written;
		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_ttybuf && sclp_chars_in_buffer(sclp_ttybuf) &&
	    !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);
	}
	spin_unlock_irqrestore(&sclp_tty_lock, flags);
out:
	return overall_written;
}

/*
 * 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, 0);
		sclp_tty_chars_count = 0;
	}
	return sclp_tty_write_string(buf, count, 1);
}

/*
 * 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 int
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, 0);
		sclp_tty_chars_count = 0;
	}
	return 1;
}

/*
 * 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, 0);
		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, 0);
		sclp_tty_chars_count = 0;
	}
}

/*
 * push input to tty
 */
static void
sclp_tty_input(unsigned char* buf, unsigned int count)
{
	struct tty_struct *tty = tty_port_tty_get(&sclp_port);
	unsigned int cchar;

	/*
	 * If this tty driver is currently closed
	 * then throw the received input away.
	 */
	if (tty == NULL)
		return;
	cchar = ctrlchar_handle(buf, count, tty);
	switch (cchar & CTRLCHAR_MASK) {
	case CTRLCHAR_SYSRQ:
		break;
	case CTRLCHAR_CTRL:
		tty_insert_flip_char(tty, cchar, TTY_NORMAL);
		tty_flip_buffer_push(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(tty, buf, count);
			tty_insert_flip_char(tty, '\n', TTY_NORMAL);
		} else
			tty_insert_flip_string(tty, buf, count - 2);
		tty_flip_buffer_push(tty);
		break;
	}
	tty_kref_put(tty);
}

/*
 * 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 *ip, *op;
	int toggle;

	/* initially changing case is off */
	toggle = 0;
	ip = op = buf;
	while (count-- > 0) {
		/* compare with special character */
		if (*ip == CASE_DELIMITER) {
			/* followed by another special character? */
			if (count && ip[1] == CASE_DELIMITER) {
				/*
				 * ... 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 (sclp_tty_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(struct gds_subvector *sv)
{
	unsigned char *str;
	int count;

	str = (unsigned char *) (sv + 1);
	count = sv->length - sizeof(*sv);
	if (sclp_tty_tolower)
		EBC_TOLOWER(str, count);
	count = sclp_switch_cases(str, count);
	/* convert EBCDIC to ASCII (modify original input in SCCB) */
	sclp_ebcasc_str(str, count);

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

static inline void sclp_eval_selfdeftextmsg(struct gds_subvector *sv)
{
	void *end;

	end = (void *) sv + sv->length;
	for (sv = sv + 1; (void *) sv < end; sv = (void *) sv + sv->length)
		if (sv->key == 0x30)
			sclp_get_input(sv);
}

static inline void sclp_eval_textcmd(struct gds_vector *v)
{
	struct gds_subvector *sv;
	void *end;

	end = (void *) v + v->length;
	for (sv = (struct gds_subvector *) (v + 1);
	     (void *) sv < end; sv = (void *) sv + sv->length)
		if (sv->key == GDS_KEY_SELFDEFTEXTMSG)
			sclp_eval_selfdeftextmsg(sv);

}

static inline void sclp_eval_cpmsu(struct gds_vector *v)
{
	void *end;

	end = (void *) v + v->length;
	for (v = v + 1; (void *) v < end; v = (void *) v + v->length)
		if (v->gds_id == GDS_ID_TEXTCMD)
			sclp_eval_textcmd(v);
}


static inline void sclp_eval_mdsmu(struct gds_vector *v)
{
	v = sclp_find_gds_vector(v + 1, (void *) v + v->length, GDS_ID_CPMSU);
	if (v)
		sclp_eval_cpmsu(v);
}

static void sclp_tty_receiver(struct evbuf_header *evbuf)
{
	struct gds_vector *v;

	v = sclp_find_gds_vector(evbuf + 1, (void *) evbuf + evbuf->length,
				 GDS_ID_MDSMU);
	if (v)
		sclp_eval_mdsmu(v);
}

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,
};

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) {
		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_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_tty_columns = 76;
		/* case input lines to lowercase */
		sclp_tty_tolower = 1;
	}
	sclp_tty_chars_count = 0;
	tty_port_init(&sclp_port);

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

	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) {
		put_tty_driver(driver);
		return rc;
	}
	sclp_tty_driver = driver;
	return 0;
}
module_init(sclp_tty_init);