sclp_vt220.c revision 6ab3d5624e172c553004ecc862bfeac16d9d68b7 
1/*
2 *  drivers/s390/char/sclp_vt220.c
3 *    SCLP VT220 terminal driver.
4 *
5 *  S390 version
6 *    Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
7 *    Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
8 */
9
10#include <linux/module.h>
11#include <linux/spinlock.h>
12#include <linux/list.h>
13#include <linux/wait.h>
14#include <linux/timer.h>
15#include <linux/kernel.h>
16#include <linux/tty.h>
17#include <linux/tty_driver.h>
18#include <linux/tty_flip.h>
19#include <linux/sched.h>
20#include <linux/errno.h>
21#include <linux/mm.h>
22#include <linux/major.h>
23#include <linux/console.h>
24#include <linux/kdev_t.h>
25#include <linux/bootmem.h>
26#include <linux/interrupt.h>
27#include <linux/init.h>
28#include <asm/uaccess.h>
29#include "sclp.h"
30
31#define SCLP_VT220_PRINT_HEADER 	"sclp vt220 tty driver: "
32#define SCLP_VT220_MAJOR		TTY_MAJOR
33#define SCLP_VT220_MINOR		65
34#define SCLP_VT220_DRIVER_NAME		"sclp_vt220"
35#define SCLP_VT220_DEVICE_NAME		"ttysclp"
36#define SCLP_VT220_CONSOLE_NAME		"ttyS"
37#define SCLP_VT220_CONSOLE_INDEX	1	/* console=ttyS1 */
38#define SCLP_VT220_BUF_SIZE		80
39
40/* Representation of a single write request */
41struct sclp_vt220_request {
42	struct list_head list;
43	struct sclp_req sclp_req;
44	int retry_count;
45};
46
47/* VT220 SCCB */
48struct sclp_vt220_sccb {
49	struct sccb_header header;
50	struct evbuf_header evbuf;
51};
52
53#define SCLP_VT220_MAX_CHARS_PER_BUFFER	(PAGE_SIZE - \
54					 sizeof(struct sclp_vt220_request) - \
55					 sizeof(struct sclp_vt220_sccb))
56
57/* Structures and data needed to register tty driver */
58static struct tty_driver *sclp_vt220_driver;
59
60/* The tty_struct that the kernel associated with us */
61static struct tty_struct *sclp_vt220_tty;
62
63/* Lock to protect internal data from concurrent access */
64static spinlock_t sclp_vt220_lock;
65
66/* List of empty pages to be used as write request buffers */
67static struct list_head sclp_vt220_empty;
68
69/* List of pending requests */
70static struct list_head sclp_vt220_outqueue;
71
72/* Number of requests in outqueue */
73static int sclp_vt220_outqueue_count;
74
75/* Wait queue used to delay write requests while we've run out of buffers */
76static wait_queue_head_t sclp_vt220_waitq;
77
78/* Timer used for delaying write requests to merge subsequent messages into
79 * a single buffer */
80static struct timer_list sclp_vt220_timer;
81
82/* Pointer to current request buffer which has been partially filled but not
83 * yet sent */
84static struct sclp_vt220_request *sclp_vt220_current_request;
85
86/* Number of characters in current request buffer */
87static int sclp_vt220_buffered_chars;
88
89/* Flag indicating whether this driver has already been initialized */
90static int sclp_vt220_initialized = 0;
91
92/* Flag indicating that sclp_vt220_current_request should really
93 * have been already queued but wasn't because the SCLP was processing
94 * another buffer */
95static int sclp_vt220_flush_later;
96
97static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
98static int __sclp_vt220_emit(struct sclp_vt220_request *request);
99static void sclp_vt220_emit_current(void);
100
101/* Registration structure for our interest in SCLP event buffers */
102static struct sclp_register sclp_vt220_register = {
103	.send_mask		= EvTyp_VT220Msg_Mask,
104	.receive_mask		= EvTyp_VT220Msg_Mask,
105	.state_change_fn	= NULL,
106	.receiver_fn		= sclp_vt220_receiver_fn
107};
108
109
110/*
111 * Put provided request buffer back into queue and check emit pending
112 * buffers if necessary.
113 */
114static void
115sclp_vt220_process_queue(struct sclp_vt220_request *request)
116{
117	unsigned long flags;
118	void *page;
119
120	do {
121		/* Put buffer back to list of empty buffers */
122		page = request->sclp_req.sccb;
123		spin_lock_irqsave(&sclp_vt220_lock, flags);
124		/* Move request from outqueue to empty queue */
125		list_del(&request->list);
126		sclp_vt220_outqueue_count--;
127		list_add_tail((struct list_head *) page, &sclp_vt220_empty);
128		/* Check if there is a pending buffer on the out queue. */
129		request = NULL;
130		if (!list_empty(&sclp_vt220_outqueue))
131			request = list_entry(sclp_vt220_outqueue.next,
132					     struct sclp_vt220_request, list);
133		spin_unlock_irqrestore(&sclp_vt220_lock, flags);
134	} while (request && __sclp_vt220_emit(request));
135	if (request == NULL && sclp_vt220_flush_later)
136		sclp_vt220_emit_current();
137	wake_up(&sclp_vt220_waitq);
138	/* Check if the tty needs a wake up call */
139	if (sclp_vt220_tty != NULL) {
140		tty_wakeup(sclp_vt220_tty);
141	}
142}
143
144#define SCLP_BUFFER_MAX_RETRY		1
145
146/*
147 * Callback through which the result of a write request is reported by the
148 * SCLP.
149 */
150static void
151sclp_vt220_callback(struct sclp_req *request, void *data)
152{
153	struct sclp_vt220_request *vt220_request;
154	struct sclp_vt220_sccb *sccb;
155
156	vt220_request = (struct sclp_vt220_request *) data;
157	if (request->status == SCLP_REQ_FAILED) {
158		sclp_vt220_process_queue(vt220_request);
159		return;
160	}
161	sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
162
163	/* Check SCLP response code and choose suitable action	*/
164	switch (sccb->header.response_code) {
165	case 0x0020 :
166		break;
167
168	case 0x05f0: /* Target resource in improper state */
169		break;
170
171	case 0x0340: /* Contained SCLP equipment check */
172		if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
173			break;
174		/* Remove processed buffers and requeue rest */
175		if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
176			/* Not all buffers were processed */
177			sccb->header.response_code = 0x0000;
178			vt220_request->sclp_req.status = SCLP_REQ_FILLED;
179			if (sclp_add_request(request) == 0)
180				return;
181		}
182		break;
183
184	case 0x0040: /* SCLP equipment check */
185		if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
186			break;
187		sccb->header.response_code = 0x0000;
188		vt220_request->sclp_req.status = SCLP_REQ_FILLED;
189		if (sclp_add_request(request) == 0)
190			return;
191		break;
192
193	default:
194		break;
195	}
196	sclp_vt220_process_queue(vt220_request);
197}
198
199/*
200 * Emit vt220 request buffer to SCLP. Return zero on success, non-zero
201 * otherwise.
202 */
203static int
204__sclp_vt220_emit(struct sclp_vt220_request *request)
205{
206	if (!(sclp_vt220_register.sclp_send_mask & EvTyp_VT220Msg_Mask)) {
207		request->sclp_req.status = SCLP_REQ_FAILED;
208		return -EIO;
209	}
210	request->sclp_req.command = SCLP_CMDW_WRITEDATA;
211	request->sclp_req.status = SCLP_REQ_FILLED;
212	request->sclp_req.callback = sclp_vt220_callback;
213	request->sclp_req.callback_data = (void *) request;
214
215	return sclp_add_request(&request->sclp_req);
216}
217
218/*
219 * Queue and emit given request.
220 */
221static void
222sclp_vt220_emit(struct sclp_vt220_request *request)
223{
224	unsigned long flags;
225	int count;
226
227	spin_lock_irqsave(&sclp_vt220_lock, flags);
228	list_add_tail(&request->list, &sclp_vt220_outqueue);
229	count = sclp_vt220_outqueue_count++;
230	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
231	/* Emit only the first buffer immediately - callback takes care of
232	 * the rest */
233	if (count == 0 && __sclp_vt220_emit(request))
234		sclp_vt220_process_queue(request);
235}
236
237/*
238 * Queue and emit current request. Return zero on success, non-zero otherwise.
239 */
240static void
241sclp_vt220_emit_current(void)
242{
243	unsigned long flags;
244	struct sclp_vt220_request *request;
245	struct sclp_vt220_sccb *sccb;
246
247	spin_lock_irqsave(&sclp_vt220_lock, flags);
248	request = NULL;
249	if (sclp_vt220_current_request != NULL) {
250		sccb = (struct sclp_vt220_sccb *)
251				sclp_vt220_current_request->sclp_req.sccb;
252		/* Only emit buffers with content */
253		if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
254			request = sclp_vt220_current_request;
255			sclp_vt220_current_request = NULL;
256			if (timer_pending(&sclp_vt220_timer))
257				del_timer(&sclp_vt220_timer);
258		}
259		sclp_vt220_flush_later = 0;
260	}
261	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
262	if (request != NULL)
263		sclp_vt220_emit(request);
264}
265
266#define SCLP_NORMAL_WRITE	0x00
267
268/*
269 * Helper function to initialize a page with the sclp request structure.
270 */
271static struct sclp_vt220_request *
272sclp_vt220_initialize_page(void *page)
273{
274	struct sclp_vt220_request *request;
275	struct sclp_vt220_sccb *sccb;
276
277	/* Place request structure at end of page */
278	request = ((struct sclp_vt220_request *)
279			((addr_t) page + PAGE_SIZE)) - 1;
280	request->retry_count = 0;
281	request->sclp_req.sccb = page;
282	/* SCCB goes at start of page */
283	sccb = (struct sclp_vt220_sccb *) page;
284	memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
285	sccb->header.length = sizeof(struct sclp_vt220_sccb);
286	sccb->header.function_code = SCLP_NORMAL_WRITE;
287	sccb->header.response_code = 0x0000;
288	sccb->evbuf.type = EvTyp_VT220Msg;
289	sccb->evbuf.length = sizeof(struct evbuf_header);
290
291	return request;
292}
293
294static inline unsigned int
295sclp_vt220_space_left(struct sclp_vt220_request *request)
296{
297	struct sclp_vt220_sccb *sccb;
298	sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
299	return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
300	       sccb->header.length;
301}
302
303static inline unsigned int
304sclp_vt220_chars_stored(struct sclp_vt220_request *request)
305{
306	struct sclp_vt220_sccb *sccb;
307	sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
308	return sccb->evbuf.length - sizeof(struct evbuf_header);
309}
310
311/*
312 * Add msg to buffer associated with request. Return the number of characters
313 * added.
314 */
315static int
316sclp_vt220_add_msg(struct sclp_vt220_request *request,
317		   const unsigned char *msg, int count, int convertlf)
318{
319	struct sclp_vt220_sccb *sccb;
320	void *buffer;
321	unsigned char c;
322	int from;
323	int to;
324
325	if (count > sclp_vt220_space_left(request))
326		count = sclp_vt220_space_left(request);
327	if (count <= 0)
328		return 0;
329
330	sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
331	buffer = (void *) ((addr_t) sccb + sccb->header.length);
332
333	if (convertlf) {
334		/* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
335		for (from=0, to=0;
336		     (from < count) && (to < sclp_vt220_space_left(request));
337		     from++) {
338			/* Retrieve character */
339			c = msg[from];
340			/* Perform conversion */
341			if (c == 0x0a) {
342				if (to + 1 < sclp_vt220_space_left(request)) {
343					((unsigned char *) buffer)[to++] = c;
344					((unsigned char *) buffer)[to++] = 0x0d;
345				} else
346					break;
347
348			} else
349				((unsigned char *) buffer)[to++] = c;
350		}
351		sccb->header.length += to;
352		sccb->evbuf.length += to;
353		return from;
354	} else {
355		memcpy(buffer, (const void *) msg, count);
356		sccb->header.length += count;
357		sccb->evbuf.length += count;
358		return count;
359	}
360}
361
362/*
363 * Emit buffer after having waited long enough for more data to arrive.
364 */
365static void
366sclp_vt220_timeout(unsigned long data)
367{
368	sclp_vt220_emit_current();
369}
370
371#define BUFFER_MAX_DELAY	HZ/2
372
373/*
374 * Internal implementation of the write function. Write COUNT bytes of data
375 * from memory at BUF
376 * to the SCLP interface. In case that the data does not fit into the current
377 * write buffer, emit the current one and allocate a new one. If there are no
378 * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
379 * is non-zero, the buffer will be scheduled for emitting after a timeout -
380 * otherwise the user has to explicitly call the flush function.
381 * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
382 * buffer should be converted to 0x0a 0x0d. After completion, return the number
383 * of bytes written.
384 */
385static int
386__sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
387		   int convertlf)
388{
389	unsigned long flags;
390	void *page;
391	int written;
392	int overall_written;
393
394	if (count <= 0)
395		return 0;
396	overall_written = 0;
397	spin_lock_irqsave(&sclp_vt220_lock, flags);
398	do {
399		/* Create a sclp output buffer if none exists yet */
400		if (sclp_vt220_current_request == NULL) {
401			while (list_empty(&sclp_vt220_empty)) {
402				spin_unlock_irqrestore(&sclp_vt220_lock,
403						       flags);
404				if (in_interrupt())
405					sclp_sync_wait();
406				else
407					wait_event(sclp_vt220_waitq,
408						!list_empty(&sclp_vt220_empty));
409				spin_lock_irqsave(&sclp_vt220_lock, flags);
410			}
411			page = (void *) sclp_vt220_empty.next;
412			list_del((struct list_head *) page);
413			sclp_vt220_current_request =
414				sclp_vt220_initialize_page(page);
415		}
416		/* Try to write the string to the current request buffer */
417		written = sclp_vt220_add_msg(sclp_vt220_current_request,
418					     buf, count, convertlf);
419		overall_written += written;
420		if (written == count)
421			break;
422		/*
423		 * Not all characters could be written to the current
424		 * output buffer. Emit the buffer, create a new buffer
425		 * and then output the rest of the string.
426		 */
427		spin_unlock_irqrestore(&sclp_vt220_lock, flags);
428		sclp_vt220_emit_current();
429		spin_lock_irqsave(&sclp_vt220_lock, flags);
430		buf += written;
431		count -= written;
432	} while (count > 0);
433	/* Setup timer to output current console buffer after some time */
434	if (sclp_vt220_current_request != NULL &&
435	    !timer_pending(&sclp_vt220_timer) && do_schedule) {
436		sclp_vt220_timer.function = sclp_vt220_timeout;
437		sclp_vt220_timer.data = 0UL;
438		sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
439		add_timer(&sclp_vt220_timer);
440	}
441	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
442	return overall_written;
443}
444
445/*
446 * This routine is called by the kernel to write a series of
447 * characters to the tty device.  The characters may come from
448 * user space or kernel space.  This routine will return the
449 * number of characters actually accepted for writing.
450 */
451static int
452sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
453{
454	return __sclp_vt220_write(buf, count, 1, 0);
455}
456
457#define SCLP_VT220_SESSION_ENDED	0x01
458#define	SCLP_VT220_SESSION_STARTED	0x80
459#define SCLP_VT220_SESSION_DATA		0x00
460
461/*
462 * Called by the SCLP to report incoming event buffers.
463 */
464static void
465sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
466{
467	char *buffer;
468	unsigned int count;
469
470	/* Ignore input if device is not open */
471	if (sclp_vt220_tty == NULL)
472		return;
473
474	buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
475	count = evbuf->length - sizeof(struct evbuf_header);
476
477	switch (*buffer) {
478	case SCLP_VT220_SESSION_ENDED:
479	case SCLP_VT220_SESSION_STARTED:
480		break;
481	case SCLP_VT220_SESSION_DATA:
482		/* Send input to line discipline */
483		buffer++;
484		count--;
485		tty_insert_flip_string(sclp_vt220_tty, buffer, count);
486		tty_flip_buffer_push(sclp_vt220_tty);
487		break;
488	}
489}
490
491/*
492 * This routine is called when a particular tty device is opened.
493 */
494static int
495sclp_vt220_open(struct tty_struct *tty, struct file *filp)
496{
497	if (tty->count == 1) {
498		sclp_vt220_tty = tty;
499		tty->driver_data = kmalloc(SCLP_VT220_BUF_SIZE, GFP_KERNEL);
500		if (tty->driver_data == NULL)
501			return -ENOMEM;
502		tty->low_latency = 0;
503	}
504	return 0;
505}
506
507/*
508 * This routine is called when a particular tty device is closed.
509 */
510static void
511sclp_vt220_close(struct tty_struct *tty, struct file *filp)
512{
513	if (tty->count == 1) {
514		sclp_vt220_tty = NULL;
515		kfree(tty->driver_data);
516		tty->driver_data = NULL;
517	}
518}
519
520/*
521 * This routine is called by the kernel to write a single
522 * character to the tty device.  If the kernel uses this routine,
523 * it must call the flush_chars() routine (if defined) when it is
524 * done stuffing characters into the driver.
525 *
526 * NOTE: include/linux/tty_driver.h specifies that a character should be
527 * ignored if there is no room in the queue. This driver implements a different
528 * semantic in that it will block when there is no more room left.
529 */
530static void
531sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
532{
533	__sclp_vt220_write(&ch, 1, 0, 0);
534}
535
536/*
537 * This routine is called by the kernel after it has written a
538 * series of characters to the tty device using put_char().
539 */
540static void
541sclp_vt220_flush_chars(struct tty_struct *tty)
542{
543	if (sclp_vt220_outqueue_count == 0)
544		sclp_vt220_emit_current();
545	else
546		sclp_vt220_flush_later = 1;
547}
548
549/*
550 * This routine returns the numbers of characters the tty driver
551 * will accept for queuing to be written.  This number is subject
552 * to change as output buffers get emptied, or if the output flow
553 * control is acted.
554 */
555static int
556sclp_vt220_write_room(struct tty_struct *tty)
557{
558	unsigned long flags;
559	struct list_head *l;
560	int count;
561
562	spin_lock_irqsave(&sclp_vt220_lock, flags);
563	count = 0;
564	if (sclp_vt220_current_request != NULL)
565		count = sclp_vt220_space_left(sclp_vt220_current_request);
566	list_for_each(l, &sclp_vt220_empty)
567		count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
568	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
569	return count;
570}
571
572/*
573 * Return number of buffered chars.
574 */
575static int
576sclp_vt220_chars_in_buffer(struct tty_struct *tty)
577{
578	unsigned long flags;
579	struct list_head *l;
580	struct sclp_vt220_request *r;
581	int count;
582
583	spin_lock_irqsave(&sclp_vt220_lock, flags);
584	count = 0;
585	if (sclp_vt220_current_request != NULL)
586		count = sclp_vt220_chars_stored(sclp_vt220_current_request);
587	list_for_each(l, &sclp_vt220_outqueue) {
588		r = list_entry(l, struct sclp_vt220_request, list);
589		count += sclp_vt220_chars_stored(r);
590	}
591	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
592	return count;
593}
594
595static void
596__sclp_vt220_flush_buffer(void)
597{
598	unsigned long flags;
599
600	sclp_vt220_emit_current();
601	spin_lock_irqsave(&sclp_vt220_lock, flags);
602	if (timer_pending(&sclp_vt220_timer))
603		del_timer(&sclp_vt220_timer);
604	while (sclp_vt220_outqueue_count > 0) {
605		spin_unlock_irqrestore(&sclp_vt220_lock, flags);
606		sclp_sync_wait();
607		spin_lock_irqsave(&sclp_vt220_lock, flags);
608	}
609	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
610}
611
612/*
613 * Pass on all buffers to the hardware. Return only when there are no more
614 * buffers pending.
615 */
616static void
617sclp_vt220_flush_buffer(struct tty_struct *tty)
618{
619	sclp_vt220_emit_current();
620}
621
622/*
623 * Initialize all relevant components and register driver with system.
624 */
625static int
626__sclp_vt220_init(int early)
627{
628	void *page;
629	int i;
630
631	if (sclp_vt220_initialized)
632		return 0;
633	sclp_vt220_initialized = 1;
634	spin_lock_init(&sclp_vt220_lock);
635	INIT_LIST_HEAD(&sclp_vt220_empty);
636	INIT_LIST_HEAD(&sclp_vt220_outqueue);
637	init_waitqueue_head(&sclp_vt220_waitq);
638	init_timer(&sclp_vt220_timer);
639	sclp_vt220_current_request = NULL;
640	sclp_vt220_buffered_chars = 0;
641	sclp_vt220_outqueue_count = 0;
642	sclp_vt220_tty = NULL;
643	sclp_vt220_flush_later = 0;
644
645	/* Allocate pages for output buffering */
646	for (i = 0; i < (early ? MAX_CONSOLE_PAGES : MAX_KMEM_PAGES); i++) {
647		if (early)
648			page = alloc_bootmem_low_pages(PAGE_SIZE);
649		else
650			page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
651		if (!page)
652			return -ENOMEM;
653		list_add_tail((struct list_head *) page, &sclp_vt220_empty);
654	}
655	return 0;
656}
657
658static struct tty_operations sclp_vt220_ops = {
659	.open = sclp_vt220_open,
660	.close = sclp_vt220_close,
661	.write = sclp_vt220_write,
662	.put_char = sclp_vt220_put_char,
663	.flush_chars = sclp_vt220_flush_chars,
664	.write_room = sclp_vt220_write_room,
665	.chars_in_buffer = sclp_vt220_chars_in_buffer,
666	.flush_buffer = sclp_vt220_flush_buffer
667};
668
669/*
670 * Register driver with SCLP and Linux and initialize internal tty structures.
671 */
672int __init
673sclp_vt220_tty_init(void)
674{
675	struct tty_driver *driver;
676	int rc;
677
678	/* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
679	 * symmetry between VM and LPAR systems regarding ttyS1. */
680	driver = alloc_tty_driver(1);
681	if (!driver)
682		return -ENOMEM;
683	rc = __sclp_vt220_init(0);
684	if (rc) {
685		put_tty_driver(driver);
686		return rc;
687	}
688	rc = sclp_register(&sclp_vt220_register);
689	if (rc) {
690		printk(KERN_ERR SCLP_VT220_PRINT_HEADER
691		       "could not register tty - "
692		       "sclp_register returned %d\n", rc);
693		put_tty_driver(driver);
694		return rc;
695	}
696
697	driver->owner = THIS_MODULE;
698	driver->driver_name = SCLP_VT220_DRIVER_NAME;
699	driver->name = SCLP_VT220_DEVICE_NAME;
700	driver->major = SCLP_VT220_MAJOR;
701	driver->minor_start = SCLP_VT220_MINOR;
702	driver->type = TTY_DRIVER_TYPE_SYSTEM;
703	driver->subtype = SYSTEM_TYPE_TTY;
704	driver->init_termios = tty_std_termios;
705	driver->flags = TTY_DRIVER_REAL_RAW;
706	tty_set_operations(driver, &sclp_vt220_ops);
707
708	rc = tty_register_driver(driver);
709	if (rc) {
710		printk(KERN_ERR SCLP_VT220_PRINT_HEADER
711		       "could not register tty - "
712		       "tty_register_driver returned %d\n", rc);
713		put_tty_driver(driver);
714		return rc;
715	}
716	sclp_vt220_driver = driver;
717	return 0;
718}
719
720module_init(sclp_vt220_tty_init);
721
722#ifdef CONFIG_SCLP_VT220_CONSOLE
723
724static void
725sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
726{
727	__sclp_vt220_write((const unsigned char *) buf, count, 1, 1);
728}
729
730static struct tty_driver *
731sclp_vt220_con_device(struct console *c, int *index)
732{
733	*index = 0;
734	return sclp_vt220_driver;
735}
736
737/*
738 * This routine is called from panic when the kernel is going to give up.
739 * We have to make sure that all buffers will be flushed to the SCLP.
740 * Note that this function may be called from within an interrupt context.
741 */
742static void
743sclp_vt220_con_unblank(void)
744{
745	__sclp_vt220_flush_buffer();
746}
747
748/* Structure needed to register with printk */
749static struct console sclp_vt220_console =
750{
751	.name = SCLP_VT220_CONSOLE_NAME,
752	.write = sclp_vt220_con_write,
753	.device = sclp_vt220_con_device,
754	.unblank = sclp_vt220_con_unblank,
755	.flags = CON_PRINTBUFFER,
756	.index = SCLP_VT220_CONSOLE_INDEX
757};
758
759static int __init
760sclp_vt220_con_init(void)
761{
762	int rc;
763
764	if (!CONSOLE_IS_SCLP)
765		return 0;
766	rc = __sclp_vt220_init(1);
767	if (rc)
768		return rc;
769	/* Attach linux console */
770	register_console(&sclp_vt220_console);
771	return 0;
772}
773
774console_initcall(sclp_vt220_con_init);
775#endif /* CONFIG_SCLP_VT220_CONSOLE */
776
777