1/*
2 * SCLP VT220 terminal driver.
3 *
4 * Copyright IBM Corp. 2003, 2009
5 *
6 * Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
7 */
8
9#include <linux/module.h>
10#include <linux/spinlock.h>
11#include <linux/list.h>
12#include <linux/wait.h>
13#include <linux/timer.h>
14#include <linux/kernel.h>
15#include <linux/tty.h>
16#include <linux/tty_driver.h>
17#include <linux/tty_flip.h>
18#include <linux/errno.h>
19#include <linux/mm.h>
20#include <linux/major.h>
21#include <linux/console.h>
22#include <linux/kdev_t.h>
23#include <linux/interrupt.h>
24#include <linux/init.h>
25#include <linux/reboot.h>
26#include <linux/slab.h>
27
28#include <asm/uaccess.h>
29#include "sclp.h"
30
31#define SCLP_VT220_MAJOR		TTY_MAJOR
32#define SCLP_VT220_MINOR		65
33#define SCLP_VT220_DRIVER_NAME		"sclp_vt220"
34#define SCLP_VT220_DEVICE_NAME		"ttysclp"
35#define SCLP_VT220_CONSOLE_NAME		"ttyS"
36#define SCLP_VT220_CONSOLE_INDEX	1	/* console=ttyS1 */
37
38/* Representation of a single write request */
39struct sclp_vt220_request {
40	struct list_head list;
41	struct sclp_req sclp_req;
42	int retry_count;
43};
44
45/* VT220 SCCB */
46struct sclp_vt220_sccb {
47	struct sccb_header header;
48	struct evbuf_header evbuf;
49};
50
51#define SCLP_VT220_MAX_CHARS_PER_BUFFER	(PAGE_SIZE - \
52					 sizeof(struct sclp_vt220_request) - \
53					 sizeof(struct sclp_vt220_sccb))
54
55/* Structures and data needed to register tty driver */
56static struct tty_driver *sclp_vt220_driver;
57
58static struct tty_port sclp_vt220_port;
59
60/* Lock to protect internal data from concurrent access */
61static spinlock_t sclp_vt220_lock;
62
63/* List of empty pages to be used as write request buffers */
64static struct list_head sclp_vt220_empty;
65
66/* List of pending requests */
67static struct list_head sclp_vt220_outqueue;
68
69/* Suspend mode flag */
70static int sclp_vt220_suspended;
71
72/* Flag that output queue is currently running */
73static int sclp_vt220_queue_running;
74
75/* Timer used for delaying write requests to merge subsequent messages into
76 * a single buffer */
77static struct timer_list sclp_vt220_timer;
78
79/* Pointer to current request buffer which has been partially filled but not
80 * yet sent */
81static struct sclp_vt220_request *sclp_vt220_current_request;
82
83/* Number of characters in current request buffer */
84static int sclp_vt220_buffered_chars;
85
86/* Counter controlling core driver initialization. */
87static int __initdata sclp_vt220_init_count;
88
89/* Flag indicating that sclp_vt220_current_request should really
90 * have been already queued but wasn't because the SCLP was processing
91 * another buffer */
92static int sclp_vt220_flush_later;
93
94static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
95static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
96				   enum sclp_pm_event sclp_pm_event);
97static int __sclp_vt220_emit(struct sclp_vt220_request *request);
98static void sclp_vt220_emit_current(void);
99
100/* Registration structure for SCLP output event buffers */
101static struct sclp_register sclp_vt220_register = {
102	.send_mask		= EVTYP_VT220MSG_MASK,
103	.pm_event_fn		= sclp_vt220_pm_event_fn,
104};
105
106/* Registration structure for SCLP input event buffers */
107static struct sclp_register sclp_vt220_register_input = {
108	.receive_mask		= EVTYP_VT220MSG_MASK,
109	.receiver_fn		= sclp_vt220_receiver_fn,
110};
111
112
113/*
114 * Put provided request buffer back into queue and check emit pending
115 * buffers if necessary.
116 */
117static void
118sclp_vt220_process_queue(struct sclp_vt220_request *request)
119{
120	unsigned long flags;
121	void *page;
122
123	do {
124		/* Put buffer back to list of empty buffers */
125		page = request->sclp_req.sccb;
126		spin_lock_irqsave(&sclp_vt220_lock, flags);
127		/* Move request from outqueue to empty queue */
128		list_del(&request->list);
129		list_add_tail((struct list_head *) page, &sclp_vt220_empty);
130		/* Check if there is a pending buffer on the out queue. */
131		request = NULL;
132		if (!list_empty(&sclp_vt220_outqueue))
133			request = list_entry(sclp_vt220_outqueue.next,
134					     struct sclp_vt220_request, list);
135		if (!request || sclp_vt220_suspended) {
136			sclp_vt220_queue_running = 0;
137			spin_unlock_irqrestore(&sclp_vt220_lock, flags);
138			break;
139		}
140		spin_unlock_irqrestore(&sclp_vt220_lock, flags);
141	} while (__sclp_vt220_emit(request));
142	if (request == NULL && sclp_vt220_flush_later)
143		sclp_vt220_emit_current();
144	tty_port_tty_wakeup(&sclp_vt220_port);
145}
146
147#define SCLP_BUFFER_MAX_RETRY		1
148
149/*
150 * Callback through which the result of a write request is reported by the
151 * SCLP.
152 */
153static void
154sclp_vt220_callback(struct sclp_req *request, void *data)
155{
156	struct sclp_vt220_request *vt220_request;
157	struct sclp_vt220_sccb *sccb;
158
159	vt220_request = (struct sclp_vt220_request *) data;
160	if (request->status == SCLP_REQ_FAILED) {
161		sclp_vt220_process_queue(vt220_request);
162		return;
163	}
164	sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
165
166	/* Check SCLP response code and choose suitable action	*/
167	switch (sccb->header.response_code) {
168	case 0x0020 :
169		break;
170
171	case 0x05f0: /* Target resource in improper state */
172		break;
173
174	case 0x0340: /* Contained SCLP equipment check */
175		if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
176			break;
177		/* Remove processed buffers and requeue rest */
178		if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
179			/* Not all buffers were processed */
180			sccb->header.response_code = 0x0000;
181			vt220_request->sclp_req.status = SCLP_REQ_FILLED;
182			if (sclp_add_request(request) == 0)
183				return;
184		}
185		break;
186
187	case 0x0040: /* SCLP equipment check */
188		if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
189			break;
190		sccb->header.response_code = 0x0000;
191		vt220_request->sclp_req.status = SCLP_REQ_FILLED;
192		if (sclp_add_request(request) == 0)
193			return;
194		break;
195
196	default:
197		break;
198	}
199	sclp_vt220_process_queue(vt220_request);
200}
201
202/*
203 * Emit vt220 request buffer to SCLP. Return zero on success, non-zero
204 * otherwise.
205 */
206static int
207__sclp_vt220_emit(struct sclp_vt220_request *request)
208{
209	request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
210	request->sclp_req.status = SCLP_REQ_FILLED;
211	request->sclp_req.callback = sclp_vt220_callback;
212	request->sclp_req.callback_data = (void *) request;
213
214	return sclp_add_request(&request->sclp_req);
215}
216
217/*
218 * Queue and emit current request.
219 */
220static void
221sclp_vt220_emit_current(void)
222{
223	unsigned long flags;
224	struct sclp_vt220_request *request;
225	struct sclp_vt220_sccb *sccb;
226
227	spin_lock_irqsave(&sclp_vt220_lock, flags);
228	if (sclp_vt220_current_request) {
229		sccb = (struct sclp_vt220_sccb *)
230				sclp_vt220_current_request->sclp_req.sccb;
231		/* Only emit buffers with content */
232		if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
233			list_add_tail(&sclp_vt220_current_request->list,
234				      &sclp_vt220_outqueue);
235			sclp_vt220_current_request = NULL;
236			if (timer_pending(&sclp_vt220_timer))
237				del_timer(&sclp_vt220_timer);
238		}
239		sclp_vt220_flush_later = 0;
240	}
241	if (sclp_vt220_queue_running || sclp_vt220_suspended)
242		goto out_unlock;
243	if (list_empty(&sclp_vt220_outqueue))
244		goto out_unlock;
245	request = list_first_entry(&sclp_vt220_outqueue,
246				   struct sclp_vt220_request, list);
247	sclp_vt220_queue_running = 1;
248	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
249
250	if (__sclp_vt220_emit(request))
251		sclp_vt220_process_queue(request);
252	return;
253out_unlock:
254	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
255}
256
257#define SCLP_NORMAL_WRITE	0x00
258
259/*
260 * Helper function to initialize a page with the sclp request structure.
261 */
262static struct sclp_vt220_request *
263sclp_vt220_initialize_page(void *page)
264{
265	struct sclp_vt220_request *request;
266	struct sclp_vt220_sccb *sccb;
267
268	/* Place request structure at end of page */
269	request = ((struct sclp_vt220_request *)
270			((addr_t) page + PAGE_SIZE)) - 1;
271	request->retry_count = 0;
272	request->sclp_req.sccb = page;
273	/* SCCB goes at start of page */
274	sccb = (struct sclp_vt220_sccb *) page;
275	memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
276	sccb->header.length = sizeof(struct sclp_vt220_sccb);
277	sccb->header.function_code = SCLP_NORMAL_WRITE;
278	sccb->header.response_code = 0x0000;
279	sccb->evbuf.type = EVTYP_VT220MSG;
280	sccb->evbuf.length = sizeof(struct evbuf_header);
281
282	return request;
283}
284
285static inline unsigned int
286sclp_vt220_space_left(struct sclp_vt220_request *request)
287{
288	struct sclp_vt220_sccb *sccb;
289	sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
290	return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
291	       sccb->header.length;
292}
293
294static inline unsigned int
295sclp_vt220_chars_stored(struct sclp_vt220_request *request)
296{
297	struct sclp_vt220_sccb *sccb;
298	sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
299	return sccb->evbuf.length - sizeof(struct evbuf_header);
300}
301
302/*
303 * Add msg to buffer associated with request. Return the number of characters
304 * added.
305 */
306static int
307sclp_vt220_add_msg(struct sclp_vt220_request *request,
308		   const unsigned char *msg, int count, int convertlf)
309{
310	struct sclp_vt220_sccb *sccb;
311	void *buffer;
312	unsigned char c;
313	int from;
314	int to;
315
316	if (count > sclp_vt220_space_left(request))
317		count = sclp_vt220_space_left(request);
318	if (count <= 0)
319		return 0;
320
321	sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
322	buffer = (void *) ((addr_t) sccb + sccb->header.length);
323
324	if (convertlf) {
325		/* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
326		for (from=0, to=0;
327		     (from < count) && (to < sclp_vt220_space_left(request));
328		     from++) {
329			/* Retrieve character */
330			c = msg[from];
331			/* Perform conversion */
332			if (c == 0x0a) {
333				if (to + 1 < sclp_vt220_space_left(request)) {
334					((unsigned char *) buffer)[to++] = c;
335					((unsigned char *) buffer)[to++] = 0x0d;
336				} else
337					break;
338
339			} else
340				((unsigned char *) buffer)[to++] = c;
341		}
342		sccb->header.length += to;
343		sccb->evbuf.length += to;
344		return from;
345	} else {
346		memcpy(buffer, (const void *) msg, count);
347		sccb->header.length += count;
348		sccb->evbuf.length += count;
349		return count;
350	}
351}
352
353/*
354 * Emit buffer after having waited long enough for more data to arrive.
355 */
356static void
357sclp_vt220_timeout(unsigned long data)
358{
359	sclp_vt220_emit_current();
360}
361
362#define BUFFER_MAX_DELAY	HZ/20
363
364/*
365 * Drop oldest console buffer if sclp_con_drop is set
366 */
367static int
368sclp_vt220_drop_buffer(void)
369{
370	struct list_head *list;
371	struct sclp_vt220_request *request;
372	void *page;
373
374	if (!sclp_console_drop)
375		return 0;
376	list = sclp_vt220_outqueue.next;
377	if (sclp_vt220_queue_running)
378		/* The first element is in I/O */
379		list = list->next;
380	if (list == &sclp_vt220_outqueue)
381		return 0;
382	list_del(list);
383	request = list_entry(list, struct sclp_vt220_request, list);
384	page = request->sclp_req.sccb;
385	list_add_tail((struct list_head *) page, &sclp_vt220_empty);
386	return 1;
387}
388
389/*
390 * Internal implementation of the write function. Write COUNT bytes of data
391 * from memory at BUF
392 * to the SCLP interface. In case that the data does not fit into the current
393 * write buffer, emit the current one and allocate a new one. If there are no
394 * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
395 * is non-zero, the buffer will be scheduled for emitting after a timeout -
396 * otherwise the user has to explicitly call the flush function.
397 * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
398 * buffer should be converted to 0x0a 0x0d. After completion, return the number
399 * of bytes written.
400 */
401static int
402__sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
403		   int convertlf, int may_fail)
404{
405	unsigned long flags;
406	void *page;
407	int written;
408	int overall_written;
409
410	if (count <= 0)
411		return 0;
412	overall_written = 0;
413	spin_lock_irqsave(&sclp_vt220_lock, flags);
414	do {
415		/* Create an sclp output buffer if none exists yet */
416		if (sclp_vt220_current_request == NULL) {
417			if (list_empty(&sclp_vt220_empty))
418				sclp_console_full++;
419			while (list_empty(&sclp_vt220_empty)) {
420				if (may_fail || sclp_vt220_suspended)
421					goto out;
422				if (sclp_vt220_drop_buffer())
423					break;
424				spin_unlock_irqrestore(&sclp_vt220_lock, flags);
425
426				sclp_sync_wait();
427				spin_lock_irqsave(&sclp_vt220_lock, flags);
428			}
429			page = (void *) sclp_vt220_empty.next;
430			list_del((struct list_head *) page);
431			sclp_vt220_current_request =
432				sclp_vt220_initialize_page(page);
433		}
434		/* Try to write the string to the current request buffer */
435		written = sclp_vt220_add_msg(sclp_vt220_current_request,
436					     buf, count, convertlf);
437		overall_written += written;
438		if (written == count)
439			break;
440		/*
441		 * Not all characters could be written to the current
442		 * output buffer. Emit the buffer, create a new buffer
443		 * and then output the rest of the string.
444		 */
445		spin_unlock_irqrestore(&sclp_vt220_lock, flags);
446		sclp_vt220_emit_current();
447		spin_lock_irqsave(&sclp_vt220_lock, flags);
448		buf += written;
449		count -= written;
450	} while (count > 0);
451	/* Setup timer to output current console buffer after some time */
452	if (sclp_vt220_current_request != NULL &&
453	    !timer_pending(&sclp_vt220_timer) && do_schedule) {
454		sclp_vt220_timer.function = sclp_vt220_timeout;
455		sclp_vt220_timer.data = 0UL;
456		sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
457		add_timer(&sclp_vt220_timer);
458	}
459out:
460	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
461	return overall_written;
462}
463
464/*
465 * This routine is called by the kernel to write a series of
466 * characters to the tty device.  The characters may come from
467 * user space or kernel space.  This routine will return the
468 * number of characters actually accepted for writing.
469 */
470static int
471sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
472{
473	return __sclp_vt220_write(buf, count, 1, 0, 1);
474}
475
476#define SCLP_VT220_SESSION_ENDED	0x01
477#define	SCLP_VT220_SESSION_STARTED	0x80
478#define SCLP_VT220_SESSION_DATA		0x00
479
480/*
481 * Called by the SCLP to report incoming event buffers.
482 */
483static void
484sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
485{
486	char *buffer;
487	unsigned int count;
488
489	buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
490	count = evbuf->length - sizeof(struct evbuf_header);
491
492	switch (*buffer) {
493	case SCLP_VT220_SESSION_ENDED:
494	case SCLP_VT220_SESSION_STARTED:
495		break;
496	case SCLP_VT220_SESSION_DATA:
497		/* Send input to line discipline */
498		buffer++;
499		count--;
500		tty_insert_flip_string(&sclp_vt220_port, buffer, count);
501		tty_flip_buffer_push(&sclp_vt220_port);
502		break;
503	}
504}
505
506/*
507 * This routine is called when a particular tty device is opened.
508 */
509static int
510sclp_vt220_open(struct tty_struct *tty, struct file *filp)
511{
512	if (tty->count == 1) {
513		tty_port_tty_set(&sclp_vt220_port, tty);
514		sclp_vt220_port.low_latency = 0;
515		if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
516			tty->winsize.ws_row = 24;
517			tty->winsize.ws_col = 80;
518		}
519	}
520	return 0;
521}
522
523/*
524 * This routine is called when a particular tty device is closed.
525 */
526static void
527sclp_vt220_close(struct tty_struct *tty, struct file *filp)
528{
529	if (tty->count == 1)
530		tty_port_tty_set(&sclp_vt220_port, NULL);
531}
532
533/*
534 * This routine is called by the kernel to write a single
535 * character to the tty device.  If the kernel uses this routine,
536 * it must call the flush_chars() routine (if defined) when it is
537 * done stuffing characters into the driver.
538 */
539static int
540sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
541{
542	return __sclp_vt220_write(&ch, 1, 0, 0, 1);
543}
544
545/*
546 * This routine is called by the kernel after it has written a
547 * series of characters to the tty device using put_char().
548 */
549static void
550sclp_vt220_flush_chars(struct tty_struct *tty)
551{
552	if (!sclp_vt220_queue_running)
553		sclp_vt220_emit_current();
554	else
555		sclp_vt220_flush_later = 1;
556}
557
558/*
559 * This routine returns the numbers of characters the tty driver
560 * will accept for queuing to be written.  This number is subject
561 * to change as output buffers get emptied, or if the output flow
562 * control is acted.
563 */
564static int
565sclp_vt220_write_room(struct tty_struct *tty)
566{
567	unsigned long flags;
568	struct list_head *l;
569	int count;
570
571	spin_lock_irqsave(&sclp_vt220_lock, flags);
572	count = 0;
573	if (sclp_vt220_current_request != NULL)
574		count = sclp_vt220_space_left(sclp_vt220_current_request);
575	list_for_each(l, &sclp_vt220_empty)
576		count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
577	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
578	return count;
579}
580
581/*
582 * Return number of buffered chars.
583 */
584static int
585sclp_vt220_chars_in_buffer(struct tty_struct *tty)
586{
587	unsigned long flags;
588	struct list_head *l;
589	struct sclp_vt220_request *r;
590	int count;
591
592	spin_lock_irqsave(&sclp_vt220_lock, flags);
593	count = 0;
594	if (sclp_vt220_current_request != NULL)
595		count = sclp_vt220_chars_stored(sclp_vt220_current_request);
596	list_for_each(l, &sclp_vt220_outqueue) {
597		r = list_entry(l, struct sclp_vt220_request, list);
598		count += sclp_vt220_chars_stored(r);
599	}
600	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
601	return count;
602}
603
604/*
605 * Pass on all buffers to the hardware. Return only when there are no more
606 * buffers pending.
607 */
608static void
609sclp_vt220_flush_buffer(struct tty_struct *tty)
610{
611	sclp_vt220_emit_current();
612}
613
614/* Release allocated pages. */
615static void __init __sclp_vt220_free_pages(void)
616{
617	struct list_head *page, *p;
618
619	list_for_each_safe(page, p, &sclp_vt220_empty) {
620		list_del(page);
621		free_page((unsigned long) page);
622	}
623}
624
625/* Release memory and unregister from sclp core. Controlled by init counting -
626 * only the last invoker will actually perform these actions. */
627static void __init __sclp_vt220_cleanup(void)
628{
629	sclp_vt220_init_count--;
630	if (sclp_vt220_init_count != 0)
631		return;
632	sclp_unregister(&sclp_vt220_register);
633	__sclp_vt220_free_pages();
634	tty_port_destroy(&sclp_vt220_port);
635}
636
637/* Allocate buffer pages and register with sclp core. Controlled by init
638 * counting - only the first invoker will actually perform these actions. */
639static int __init __sclp_vt220_init(int num_pages)
640{
641	void *page;
642	int i;
643	int rc;
644
645	sclp_vt220_init_count++;
646	if (sclp_vt220_init_count != 1)
647		return 0;
648	spin_lock_init(&sclp_vt220_lock);
649	INIT_LIST_HEAD(&sclp_vt220_empty);
650	INIT_LIST_HEAD(&sclp_vt220_outqueue);
651	init_timer(&sclp_vt220_timer);
652	tty_port_init(&sclp_vt220_port);
653	sclp_vt220_current_request = NULL;
654	sclp_vt220_buffered_chars = 0;
655	sclp_vt220_flush_later = 0;
656
657	/* Allocate pages for output buffering */
658	rc = -ENOMEM;
659	for (i = 0; i < num_pages; i++) {
660		page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
661		if (!page)
662			goto out;
663		list_add_tail(page, &sclp_vt220_empty);
664	}
665	rc = sclp_register(&sclp_vt220_register);
666out:
667	if (rc) {
668		__sclp_vt220_free_pages();
669		sclp_vt220_init_count--;
670		tty_port_destroy(&sclp_vt220_port);
671	}
672	return rc;
673}
674
675static const struct tty_operations sclp_vt220_ops = {
676	.open = sclp_vt220_open,
677	.close = sclp_vt220_close,
678	.write = sclp_vt220_write,
679	.put_char = sclp_vt220_put_char,
680	.flush_chars = sclp_vt220_flush_chars,
681	.write_room = sclp_vt220_write_room,
682	.chars_in_buffer = sclp_vt220_chars_in_buffer,
683	.flush_buffer = sclp_vt220_flush_buffer,
684};
685
686/*
687 * Register driver with SCLP and Linux and initialize internal tty structures.
688 */
689static int __init sclp_vt220_tty_init(void)
690{
691	struct tty_driver *driver;
692	int rc;
693
694	/* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
695	 * symmetry between VM and LPAR systems regarding ttyS1. */
696	driver = alloc_tty_driver(1);
697	if (!driver)
698		return -ENOMEM;
699	rc = __sclp_vt220_init(MAX_KMEM_PAGES);
700	if (rc)
701		goto out_driver;
702
703	driver->driver_name = SCLP_VT220_DRIVER_NAME;
704	driver->name = SCLP_VT220_DEVICE_NAME;
705	driver->major = SCLP_VT220_MAJOR;
706	driver->minor_start = SCLP_VT220_MINOR;
707	driver->type = TTY_DRIVER_TYPE_SYSTEM;
708	driver->subtype = SYSTEM_TYPE_TTY;
709	driver->init_termios = tty_std_termios;
710	driver->flags = TTY_DRIVER_REAL_RAW;
711	tty_set_operations(driver, &sclp_vt220_ops);
712	tty_port_link_device(&sclp_vt220_port, driver, 0);
713
714	rc = tty_register_driver(driver);
715	if (rc)
716		goto out_init;
717	rc = sclp_register(&sclp_vt220_register_input);
718	if (rc)
719		goto out_reg;
720	sclp_vt220_driver = driver;
721	return 0;
722
723out_reg:
724	tty_unregister_driver(driver);
725out_init:
726	__sclp_vt220_cleanup();
727out_driver:
728	put_tty_driver(driver);
729	return rc;
730}
731__initcall(sclp_vt220_tty_init);
732
733static void __sclp_vt220_flush_buffer(void)
734{
735	unsigned long flags;
736
737	sclp_vt220_emit_current();
738	spin_lock_irqsave(&sclp_vt220_lock, flags);
739	if (timer_pending(&sclp_vt220_timer))
740		del_timer(&sclp_vt220_timer);
741	while (sclp_vt220_queue_running) {
742		spin_unlock_irqrestore(&sclp_vt220_lock, flags);
743		sclp_sync_wait();
744		spin_lock_irqsave(&sclp_vt220_lock, flags);
745	}
746	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
747}
748
749/*
750 * Resume console: If there are cached messages, emit them.
751 */
752static void sclp_vt220_resume(void)
753{
754	unsigned long flags;
755
756	spin_lock_irqsave(&sclp_vt220_lock, flags);
757	sclp_vt220_suspended = 0;
758	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
759	sclp_vt220_emit_current();
760}
761
762/*
763 * Suspend console: Set suspend flag and flush console
764 */
765static void sclp_vt220_suspend(void)
766{
767	unsigned long flags;
768
769	spin_lock_irqsave(&sclp_vt220_lock, flags);
770	sclp_vt220_suspended = 1;
771	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
772	__sclp_vt220_flush_buffer();
773}
774
775static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
776				   enum sclp_pm_event sclp_pm_event)
777{
778	switch (sclp_pm_event) {
779	case SCLP_PM_EVENT_FREEZE:
780		sclp_vt220_suspend();
781		break;
782	case SCLP_PM_EVENT_RESTORE:
783	case SCLP_PM_EVENT_THAW:
784		sclp_vt220_resume();
785		break;
786	}
787}
788
789#ifdef CONFIG_SCLP_VT220_CONSOLE
790
791static void
792sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
793{
794	__sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
795}
796
797static struct tty_driver *
798sclp_vt220_con_device(struct console *c, int *index)
799{
800	*index = 0;
801	return sclp_vt220_driver;
802}
803
804static int
805sclp_vt220_notify(struct notifier_block *self,
806			  unsigned long event, void *data)
807{
808	__sclp_vt220_flush_buffer();
809	return NOTIFY_OK;
810}
811
812static struct notifier_block on_panic_nb = {
813	.notifier_call = sclp_vt220_notify,
814	.priority = 1,
815};
816
817static struct notifier_block on_reboot_nb = {
818	.notifier_call = sclp_vt220_notify,
819	.priority = 1,
820};
821
822/* Structure needed to register with printk */
823static struct console sclp_vt220_console =
824{
825	.name = SCLP_VT220_CONSOLE_NAME,
826	.write = sclp_vt220_con_write,
827	.device = sclp_vt220_con_device,
828	.flags = CON_PRINTBUFFER,
829	.index = SCLP_VT220_CONSOLE_INDEX
830};
831
832static int __init
833sclp_vt220_con_init(void)
834{
835	int rc;
836
837	rc = __sclp_vt220_init(sclp_console_pages);
838	if (rc)
839		return rc;
840	/* Attach linux console */
841	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
842	register_reboot_notifier(&on_reboot_nb);
843	register_console(&sclp_vt220_console);
844	return 0;
845}
846
847console_initcall(sclp_vt220_con_init);
848#endif /* CONFIG_SCLP_VT220_CONSOLE */
849
850