[PATCH] const struct tty_operations
[linux-3.10.git] / drivers / s390 / char / sclp_vt220.c
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 */
41 struct sclp_vt220_request {
42         struct list_head list;
43         struct sclp_req sclp_req;
44         int retry_count;
45 };
46
47 /* VT220 SCCB */
48 struct 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 */
58 static struct tty_driver *sclp_vt220_driver;
59
60 /* The tty_struct that the kernel associated with us */
61 static struct tty_struct *sclp_vt220_tty;
62
63 /* Lock to protect internal data from concurrent access */
64 static spinlock_t sclp_vt220_lock;
65
66 /* List of empty pages to be used as write request buffers */
67 static struct list_head sclp_vt220_empty;
68
69 /* List of pending requests */
70 static struct list_head sclp_vt220_outqueue;
71
72 /* Number of requests in outqueue */
73 static int sclp_vt220_outqueue_count;
74
75 /* Wait queue used to delay write requests while we've run out of buffers */
76 static wait_queue_head_t sclp_vt220_waitq;
77
78 /* Timer used for delaying write requests to merge subsequent messages into
79  * a single buffer */
80 static struct timer_list sclp_vt220_timer;
81
82 /* Pointer to current request buffer which has been partially filled but not
83  * yet sent */
84 static struct sclp_vt220_request *sclp_vt220_current_request;
85
86 /* Number of characters in current request buffer */
87 static int sclp_vt220_buffered_chars;
88
89 /* Flag indicating whether this driver has already been initialized */
90 static 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 */
95 static int sclp_vt220_flush_later;
96
97 static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
98 static int __sclp_vt220_emit(struct sclp_vt220_request *request);
99 static void sclp_vt220_emit_current(void);
100
101 /* Registration structure for our interest in SCLP event buffers */
102 static 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  */
114 static void
115 sclp_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  */
150 static void
151 sclp_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  */
203 static 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  */
221 static void
222 sclp_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  */
240 static void
241 sclp_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  */
271 static struct sclp_vt220_request *
272 sclp_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
294 static inline unsigned int
295 sclp_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
303 static inline unsigned int
304 sclp_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  */
315 static int
316 sclp_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  */
365 static void
366 sclp_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  */
385 static 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  */
451 static int
452 sclp_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  */
464 static void
465 sclp_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  */
494 static int
495 sclp_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  */
510 static void
511 sclp_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  */
530 static void
531 sclp_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  */
540 static void
541 sclp_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  */
555 static int
556 sclp_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  */
575 static int
576 sclp_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
595 static 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  */
616 static void
617 sclp_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  */
625 static 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
658 static const 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  */
672 int __init
673 sclp_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
720 module_init(sclp_vt220_tty_init);
721
722 #ifdef CONFIG_SCLP_VT220_CONSOLE
723
724 static void
725 sclp_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
730 static struct tty_driver *
731 sclp_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  */
742 static void
743 sclp_vt220_con_unblank(void)
744 {
745         __sclp_vt220_flush_buffer();
746 }
747
748 /* Structure needed to register with printk */
749 static 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
759 static int __init
760 sclp_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
774 console_initcall(sclp_vt220_con_init);
775 #endif /* CONFIG_SCLP_VT220_CONSOLE */
776