summaryrefslogtreecommitdiffstats
path: root/drivers/s390/char/sclp_rw.c
blob: 91b26df5227d7b69ec7f82be9bbb807d7e9770e4 (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
/*
 * driver: reading from and writing to system console on S/390 via SCLP
 *
 * Copyright IBM Corp. 1999, 2009
 *
 * Author(s): Martin Peschke <mpeschke@de.ibm.com>
 *	      Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#include <linux/kmod.h>
#include <linux/types.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/spinlock.h>
#include <linux/ctype.h>
#include <linux/uaccess.h>

#include "sclp.h"
#include "sclp_rw.h"

/*
 * The room for the SCCB (only for writing) is not equal to a pages size
 * (as it is specified as the maximum size in the SCLP documentation)
 * because of the additional data structure described above.
 */
#define MAX_SCCB_ROOM (PAGE_SIZE - sizeof(struct sclp_buffer))

static void sclp_rw_pm_event(struct sclp_register *reg,
			     enum sclp_pm_event sclp_pm_event)
{
	sclp_console_pm_event(sclp_pm_event);
}

/* Event type structure for write message and write priority message */
static struct sclp_register sclp_rw_event = {
	.send_mask = EVTYP_MSG_MASK,
	.pm_event_fn = sclp_rw_pm_event,
};

/*
 * Setup a sclp write buffer. Gets a page as input (4K) and returns
 * a pointer to a struct sclp_buffer structure that is located at the
 * end of the input page. This reduces the buffer space by a few
 * bytes but simplifies things.
 */
struct sclp_buffer *
sclp_make_buffer(void *page, unsigned short columns, unsigned short htab)
{
	struct sclp_buffer *buffer;
	struct sccb_header *sccb;

	sccb = (struct sccb_header *) page;
	/*
	 * We keep the struct sclp_buffer structure at the end
	 * of the sccb page.
	 */
	buffer = ((struct sclp_buffer *) ((addr_t) sccb + PAGE_SIZE)) - 1;
	buffer->sccb = sccb;
	buffer->retry_count = 0;
	buffer->messages = 0;
	buffer->char_sum = 0;
	buffer->current_line = NULL;
	buffer->current_length = 0;
	buffer->columns = columns;
	buffer->htab = htab;

	/* initialize sccb */
	memset(sccb, 0, sizeof(struct sccb_header));
	sccb->length = sizeof(struct sccb_header);

	return buffer;
}

/*
 * Return a pointer to the original page that has been used to create
 * the buffer.
 */
void *
sclp_unmake_buffer(struct sclp_buffer *buffer)
{
	return buffer->sccb;
}

/*
 * Initialize a new message the end of the provided buffer with
 * enough room for max_len characters. Return 0 on success.
 */
static int
sclp_initialize_mto(struct sclp_buffer *buffer, int max_len)
{
	struct sccb_header *sccb;
	struct msg_buf *msg;
	struct mdb *mdb;
	struct go *go;
	struct mto *mto;
	int msg_size;

	/* max size of new message including message text  */
	msg_size = sizeof(struct msg_buf) + max_len;

	/* check if current buffer sccb can contain the mto */
	sccb = buffer->sccb;
	if ((MAX_SCCB_ROOM - sccb->length) < msg_size)
		return -ENOMEM;

	msg = (struct msg_buf *)((addr_t) sccb + sccb->length);
	memset(msg, 0, sizeof(struct msg_buf));
	msg->header.length = sizeof(struct msg_buf);
	msg->header.type = EVTYP_MSG;

	mdb = &msg->mdb;
	mdb->header.length = sizeof(struct mdb);
	mdb->header.type = 1;
	mdb->header.tag = 0xD4C4C240;	/* ebcdic "MDB " */
	mdb->header.revision_code = 1;

	go = &mdb->go;
	go->length = sizeof(struct go);
	go->type = 1;

	mto = &mdb->mto;
	mto->length = sizeof(struct mto);
	mto->type = 4;	/* message text object */
	mto->line_type_flags = LNTPFLGS_ENDTEXT; /* end text */

	/* set pointer to first byte after struct mto. */
	buffer->current_msg = msg;
	buffer->current_line = (char *) (mto + 1);
	buffer->current_length = 0;

	return 0;
}

/*
 * Finalize message initialized by sclp_initialize_mto(),
 * updating the sizes of MTO, enclosing MDB, event buffer and SCCB.
 */
static void
sclp_finalize_mto(struct sclp_buffer *buffer)
{
	struct sccb_header *sccb;
	struct msg_buf *msg;

	/*
	 * update values of sizes
	 * (SCCB, Event(Message) Buffer, Message Data Block)
	 */
	sccb = buffer->sccb;
	msg = buffer->current_msg;
	msg->header.length += buffer->current_length;
	msg->mdb.header.length += buffer->current_length;
	msg->mdb.mto.length += buffer->current_length;
	sccb->length += msg->header.length;

	/*
	 * count number of buffered messages (= number of Message Text
	 * Objects) and number of buffered characters
	 * for the SCCB currently used for buffering and at all
	 */
	buffer->messages++;
	buffer->char_sum += buffer->current_length;

	buffer->current_line = NULL;
	buffer->current_length = 0;
	buffer->current_msg = NULL;
}

/*
 * processing of a message including escape characters,
 * returns number of characters written to the output sccb
 * ("processed" means that is not guaranteed that the character have already
 *  been sent to the SCLP but that it will be done at least next time the SCLP
 *  is not busy)
 */
int
sclp_write(struct sclp_buffer *buffer, const unsigned char *msg, int count)
{
	int spaces, i_msg;
	int rc;

	/*
	 * parse msg for escape sequences (\t,\v ...) and put formated
	 * msg into an mto (created by sclp_initialize_mto).
	 *
	 * We have to do this work ourselfs because there is no support for
	 * these characters on the native machine and only partial support
	 * under VM (Why does VM interpret \n but the native machine doesn't ?)
	 *
	 * Depending on i/o-control setting the message is always written
	 * immediately or we wait for a final new line maybe coming with the
	 * next message. Besides we avoid a buffer overrun by writing its
	 * content.
	 *
	 * RESTRICTIONS:
	 *
	 * \r and \b work within one line because we are not able to modify
	 * previous output that have already been accepted by the SCLP.
	 *
	 * \t combined with following \r is not correctly represented because
	 * \t is expanded to some spaces but \r does not know about a
	 * previous \t and decreases the current position by one column.
	 * This is in order to a slim and quick implementation.
	 */
	for (i_msg = 0; i_msg < count; i_msg++) {
		switch (msg[i_msg]) {
		case '\n':	/* new line, line feed (ASCII)	*/
			/* check if new mto needs to be created */
			if (buffer->current_line == NULL) {
				rc = sclp_initialize_mto(buffer, 0);
				if (rc)
					return i_msg;
			}
			sclp_finalize_mto(buffer);
			break;
		case '\a':	/* bell, one for several times	*/
			/* set SCLP sound alarm bit in General Object */
			if (buffer->current_line == NULL) {
				rc = sclp_initialize_mto(buffer,
							 buffer->columns);
				if (rc)
					return i_msg;
			}
			buffer->current_msg->mdb.go.general_msg_flags |=
				GNRLMSGFLGS_SNDALRM;
			break;
		case '\t':	/* horizontal tabulator	 */
			/* check if new mto needs to be created */
			if (buffer->current_line == NULL) {
				rc = sclp_initialize_mto(buffer,
							 buffer->columns);
				if (rc)
					return i_msg;
			}
			/* "go to (next htab-boundary + 1, same line)" */
			do {
				if (buffer->current_length >= buffer->columns)
					break;
				/* ok, add a blank */
				*buffer->current_line++ = 0x40;
				buffer->current_length++;
			} while (buffer->current_length % buffer->htab);
			break;
		case '\f':	/* form feed  */
		case '\v':	/* vertical tabulator  */
			/* "go to (actual column, actual line + 1)" */
			/* = new line, leading spaces */
			if (buffer->current_line != NULL) {
				spaces = buffer->current_length;
				sclp_finalize_mto(buffer);
				rc = sclp_initialize_mto(buffer,
							 buffer->columns);
				if (rc)
					return i_msg;
				memset(buffer->current_line, 0x40, spaces);
				buffer->current_line += spaces;
				buffer->current_length = spaces;
			} else {
				/* one an empty line this is the same as \n */
				rc = sclp_initialize_mto(buffer,
							 buffer->columns);
				if (rc)
					return i_msg;
				sclp_finalize_mto(buffer);
			}
			break;
		case '\b':	/* backspace  */
			/* "go to (actual column - 1, actual line)" */
			/* decrement counter indicating position, */
			/* do not remove last character */
			if (buffer->current_line != NULL &&
			    buffer->current_length > 0) {
				buffer->current_length--;
				buffer->current_line--;
			}
			break;
		case 0x00:	/* end of string  */
			/* transfer current line to SCCB */
			if (buffer->current_line != NULL)
				sclp_finalize_mto(buffer);
			/* skip the rest of the message including the 0 byte */
			i_msg = count - 1;
			break;
		default:	/* no escape character	*/
			/* do not output unprintable characters */
			if (!isprint(msg[i_msg]))
				break;
			/* check if new mto needs to be created */
			if (buffer->current_line == NULL) {
				rc = sclp_initialize_mto(buffer,
							 buffer->columns);
				if (rc)
					return i_msg;
			}
			*buffer->current_line++ = sclp_ascebc(msg[i_msg]);
			buffer->current_length++;
			break;
		}
		/* check if current mto is full */
		if (buffer->current_line != NULL &&
		    buffer->current_length >= buffer->columns)
			sclp_finalize_mto(buffer);
	}

	/* return number of processed characters */
	return i_msg;
}

/*
 * Return the number of free bytes in the sccb
 */
int
sclp_buffer_space(struct sclp_buffer *buffer)
{
	struct sccb_header *sccb;
	int count;

	sccb = buffer->sccb;
	count = MAX_SCCB_ROOM - sccb->length;
	if (buffer->current_line != NULL)
		count -= sizeof(struct msg_buf) + buffer->current_length;
	return count;
}

/*
 * Return number of characters in buffer
 */
int
sclp_chars_in_buffer(struct sclp_buffer *buffer)
{
	int count;

	count = buffer->char_sum;
	if (buffer->current_line != NULL)
		count += buffer->current_length;
	return count;
}

/*
 * sets or provides some values that influence the drivers behaviour
 */
void
sclp_set_columns(struct sclp_buffer *buffer, unsigned short columns)
{
	buffer->columns = columns;
	if (buffer->current_line != NULL &&
	    buffer->current_length > buffer->columns)
		sclp_finalize_mto(buffer);
}

void
sclp_set_htab(struct sclp_buffer *buffer, unsigned short htab)
{
	buffer->htab = htab;
}

/*
 * called by sclp_console_init and/or sclp_tty_init
 */
int
sclp_rw_init(void)
{
	static int init_done = 0;
	int rc;

	if (init_done)
		return 0;

	rc = sclp_register(&sclp_rw_event);
	if (rc == 0)
		init_done = 1;
	return rc;
}

#define SCLP_BUFFER_MAX_RETRY		1

/*
 * second half of Write Event Data-function that has to be done after
 * interruption indicating completion of Service Call.
 */
static void
sclp_writedata_callback(struct sclp_req *request, void *data)
{
	int rc;
	struct sclp_buffer *buffer;
	struct sccb_header *sccb;

	buffer = (struct sclp_buffer *) data;
	sccb = buffer->sccb;

	if (request->status == SCLP_REQ_FAILED) {
		if (buffer->callback != NULL)
			buffer->callback(buffer, -EIO);
		return;
	}
	/* check SCLP response code and choose suitable action	*/
	switch (sccb->response_code) {
	case 0x0020 :
		/* Normal completion, buffer processed, message(s) sent */
		rc = 0;
		break;

	case 0x0340: /* Contained SCLP equipment check */
		if (++buffer->retry_count > SCLP_BUFFER_MAX_RETRY) {
			rc = -EIO;
			break;
		}
		/* remove processed buffers and requeue rest */
		if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
			/* not all buffers were processed */
			sccb->response_code = 0x0000;
			buffer->request.status = SCLP_REQ_FILLED;
			rc = sclp_add_request(request);
			if (rc == 0)
				return;
		} else
			rc = 0;
		break;

	case 0x0040: /* SCLP equipment check */
	case 0x05f0: /* Target resource in improper state */
		if (++buffer->retry_count > SCLP_BUFFER_MAX_RETRY) {
			rc = -EIO;
			break;
		}
		/* retry request */
		sccb->response_code = 0x0000;
		buffer->request.status = SCLP_REQ_FILLED;
		rc = sclp_add_request(request);
		if (rc == 0)
			return;
		break;
	default:
		if (sccb->response_code == 0x71f0)
			rc = -ENOMEM;
		else
			rc = -EINVAL;
		break;
	}
	if (buffer->callback != NULL)
		buffer->callback(buffer, rc);
}

/*
 * Setup the request structure in the struct sclp_buffer to do SCLP Write
 * Event Data and pass the request to the core SCLP loop. Return zero on
 * success, non-zero otherwise.
 */
int
sclp_emit_buffer(struct sclp_buffer *buffer,
		 void (*callback)(struct sclp_buffer *, int))
{
	/* add current line if there is one */
	if (buffer->current_line != NULL)
		sclp_finalize_mto(buffer);

	/* Are there messages in the output buffer ? */
	if (buffer->messages == 0)
		return -EIO;

	buffer->request.command = SCLP_CMDW_WRITE_EVENT_DATA;
	buffer->request.status = SCLP_REQ_FILLED;
	buffer->request.callback = sclp_writedata_callback;
	buffer->request.callback_data = buffer;
	buffer->request.sccb = buffer->sccb;
	buffer->callback = callback;
	return sclp_add_request(&buffer->request);
}
OpenPOWER on IntegriCloud