Merge phase #3 (IOMMU) of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux...
[linux-2.6] / 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 IBM Corp. 2003,2008
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/errno.h>
20 #include <linux/mm.h>
21 #include <linux/major.h>
22 #include <linux/console.h>
23 #include <linux/kdev_t.h>
24 #include <linux/bootmem.h>
25 #include <linux/interrupt.h>
26 #include <linux/init.h>
27 #include <linux/reboot.h>
28
29 #include <asm/uaccess.h>
30 #include "sclp.h"
31
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 /* Timer used for delaying write requests to merge subsequent messages into
76  * a single buffer */
77 static struct timer_list sclp_vt220_timer;
78
79 /* Pointer to current request buffer which has been partially filled but not
80  * yet sent */
81 static struct sclp_vt220_request *sclp_vt220_current_request;
82
83 /* Number of characters in current request buffer */
84 static int sclp_vt220_buffered_chars;
85
86 /* Counter controlling core driver initialization. */
87 static 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 */
92 static int sclp_vt220_flush_later;
93
94 static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
95 static int __sclp_vt220_emit(struct sclp_vt220_request *request);
96 static void sclp_vt220_emit_current(void);
97
98 /* Registration structure for our interest in SCLP event buffers */
99 static struct sclp_register sclp_vt220_register = {
100         .send_mask              = EVTYP_VT220MSG_MASK,
101         .receive_mask           = EVTYP_VT220MSG_MASK,
102         .state_change_fn        = NULL,
103         .receiver_fn            = sclp_vt220_receiver_fn
104 };
105
106
107 /*
108  * Put provided request buffer back into queue and check emit pending
109  * buffers if necessary.
110  */
111 static void
112 sclp_vt220_process_queue(struct sclp_vt220_request *request)
113 {
114         unsigned long flags;
115         void *page;
116
117         do {
118                 /* Put buffer back to list of empty buffers */
119                 page = request->sclp_req.sccb;
120                 spin_lock_irqsave(&sclp_vt220_lock, flags);
121                 /* Move request from outqueue to empty queue */
122                 list_del(&request->list);
123                 sclp_vt220_outqueue_count--;
124                 list_add_tail((struct list_head *) page, &sclp_vt220_empty);
125                 /* Check if there is a pending buffer on the out queue. */
126                 request = NULL;
127                 if (!list_empty(&sclp_vt220_outqueue))
128                         request = list_entry(sclp_vt220_outqueue.next,
129                                              struct sclp_vt220_request, list);
130                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
131         } while (request && __sclp_vt220_emit(request));
132         if (request == NULL && sclp_vt220_flush_later)
133                 sclp_vt220_emit_current();
134         /* Check if the tty needs a wake up call */
135         if (sclp_vt220_tty != NULL) {
136                 tty_wakeup(sclp_vt220_tty);
137         }
138 }
139
140 #define SCLP_BUFFER_MAX_RETRY           1
141
142 /*
143  * Callback through which the result of a write request is reported by the
144  * SCLP.
145  */
146 static void
147 sclp_vt220_callback(struct sclp_req *request, void *data)
148 {
149         struct sclp_vt220_request *vt220_request;
150         struct sclp_vt220_sccb *sccb;
151
152         vt220_request = (struct sclp_vt220_request *) data;
153         if (request->status == SCLP_REQ_FAILED) {
154                 sclp_vt220_process_queue(vt220_request);
155                 return;
156         }
157         sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
158
159         /* Check SCLP response code and choose suitable action  */
160         switch (sccb->header.response_code) {
161         case 0x0020 :
162                 break;
163
164         case 0x05f0: /* Target resource in improper state */
165                 break;
166
167         case 0x0340: /* Contained SCLP equipment check */
168                 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
169                         break;
170                 /* Remove processed buffers and requeue rest */
171                 if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
172                         /* Not all buffers were processed */
173                         sccb->header.response_code = 0x0000;
174                         vt220_request->sclp_req.status = SCLP_REQ_FILLED;
175                         if (sclp_add_request(request) == 0)
176                                 return;
177                 }
178                 break;
179
180         case 0x0040: /* SCLP equipment check */
181                 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
182                         break;
183                 sccb->header.response_code = 0x0000;
184                 vt220_request->sclp_req.status = SCLP_REQ_FILLED;
185                 if (sclp_add_request(request) == 0)
186                         return;
187                 break;
188
189         default:
190                 break;
191         }
192         sclp_vt220_process_queue(vt220_request);
193 }
194
195 /*
196  * Emit vt220 request buffer to SCLP. Return zero on success, non-zero
197  * otherwise.
198  */
199 static int
200 __sclp_vt220_emit(struct sclp_vt220_request *request)
201 {
202         if (!(sclp_vt220_register.sclp_receive_mask & EVTYP_VT220MSG_MASK)) {
203                 request->sclp_req.status = SCLP_REQ_FAILED;
204                 return -EIO;
205         }
206         request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
207         request->sclp_req.status = SCLP_REQ_FILLED;
208         request->sclp_req.callback = sclp_vt220_callback;
209         request->sclp_req.callback_data = (void *) request;
210
211         return sclp_add_request(&request->sclp_req);
212 }
213
214 /*
215  * Queue and emit given request.
216  */
217 static void
218 sclp_vt220_emit(struct sclp_vt220_request *request)
219 {
220         unsigned long flags;
221         int count;
222
223         spin_lock_irqsave(&sclp_vt220_lock, flags);
224         list_add_tail(&request->list, &sclp_vt220_outqueue);
225         count = sclp_vt220_outqueue_count++;
226         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
227         /* Emit only the first buffer immediately - callback takes care of
228          * the rest */
229         if (count == 0 && __sclp_vt220_emit(request))
230                 sclp_vt220_process_queue(request);
231 }
232
233 /*
234  * Queue and emit current request. Return zero on success, non-zero otherwise.
235  */
236 static void
237 sclp_vt220_emit_current(void)
238 {
239         unsigned long flags;
240         struct sclp_vt220_request *request;
241         struct sclp_vt220_sccb *sccb;
242
243         spin_lock_irqsave(&sclp_vt220_lock, flags);
244         request = NULL;
245         if (sclp_vt220_current_request != NULL) {
246                 sccb = (struct sclp_vt220_sccb *) 
247                                 sclp_vt220_current_request->sclp_req.sccb;
248                 /* Only emit buffers with content */
249                 if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
250                         request = sclp_vt220_current_request;
251                         sclp_vt220_current_request = NULL;
252                         if (timer_pending(&sclp_vt220_timer))
253                                 del_timer(&sclp_vt220_timer);
254                 }
255                 sclp_vt220_flush_later = 0;
256         }
257         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
258         if (request != NULL)
259                 sclp_vt220_emit(request);
260 }
261
262 #define SCLP_NORMAL_WRITE       0x00
263
264 /*
265  * Helper function to initialize a page with the sclp request structure.
266  */
267 static struct sclp_vt220_request *
268 sclp_vt220_initialize_page(void *page)
269 {
270         struct sclp_vt220_request *request;
271         struct sclp_vt220_sccb *sccb;
272
273         /* Place request structure at end of page */
274         request = ((struct sclp_vt220_request *)
275                         ((addr_t) page + PAGE_SIZE)) - 1;
276         request->retry_count = 0;
277         request->sclp_req.sccb = page;
278         /* SCCB goes at start of page */
279         sccb = (struct sclp_vt220_sccb *) page;
280         memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
281         sccb->header.length = sizeof(struct sclp_vt220_sccb);
282         sccb->header.function_code = SCLP_NORMAL_WRITE;
283         sccb->header.response_code = 0x0000;
284         sccb->evbuf.type = EVTYP_VT220MSG;
285         sccb->evbuf.length = sizeof(struct evbuf_header);
286
287         return request;
288 }
289
290 static inline unsigned int
291 sclp_vt220_space_left(struct sclp_vt220_request *request)
292 {
293         struct sclp_vt220_sccb *sccb;
294         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
295         return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
296                sccb->header.length;
297 }
298
299 static inline unsigned int
300 sclp_vt220_chars_stored(struct sclp_vt220_request *request)
301 {
302         struct sclp_vt220_sccb *sccb;
303         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
304         return sccb->evbuf.length - sizeof(struct evbuf_header);
305 }
306
307 /*
308  * Add msg to buffer associated with request. Return the number of characters
309  * added.
310  */
311 static int
312 sclp_vt220_add_msg(struct sclp_vt220_request *request,
313                    const unsigned char *msg, int count, int convertlf)
314 {
315         struct sclp_vt220_sccb *sccb;
316         void *buffer;
317         unsigned char c;
318         int from;
319         int to;
320
321         if (count > sclp_vt220_space_left(request))
322                 count = sclp_vt220_space_left(request);
323         if (count <= 0)
324                 return 0;
325
326         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
327         buffer = (void *) ((addr_t) sccb + sccb->header.length);
328
329         if (convertlf) {
330                 /* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
331                 for (from=0, to=0;
332                      (from < count) && (to < sclp_vt220_space_left(request));
333                      from++) {
334                         /* Retrieve character */
335                         c = msg[from];
336                         /* Perform conversion */
337                         if (c == 0x0a) {
338                                 if (to + 1 < sclp_vt220_space_left(request)) {
339                                         ((unsigned char *) buffer)[to++] = c;
340                                         ((unsigned char *) buffer)[to++] = 0x0d;
341                                 } else
342                                         break;
343
344                         } else
345                                 ((unsigned char *) buffer)[to++] = c;
346                 }
347                 sccb->header.length += to;
348                 sccb->evbuf.length += to;
349                 return from;
350         } else {
351                 memcpy(buffer, (const void *) msg, count);
352                 sccb->header.length += count;
353                 sccb->evbuf.length += count;
354                 return count;
355         }
356 }
357
358 /*
359  * Emit buffer after having waited long enough for more data to arrive.
360  */
361 static void
362 sclp_vt220_timeout(unsigned long data)
363 {
364         sclp_vt220_emit_current();
365 }
366
367 #define BUFFER_MAX_DELAY        HZ/20
368
369 /* 
370  * Internal implementation of the write function. Write COUNT bytes of data
371  * from memory at BUF
372  * to the SCLP interface. In case that the data does not fit into the current
373  * write buffer, emit the current one and allocate a new one. If there are no
374  * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
375  * is non-zero, the buffer will be scheduled for emitting after a timeout -
376  * otherwise the user has to explicitly call the flush function.
377  * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
378  * buffer should be converted to 0x0a 0x0d. After completion, return the number
379  * of bytes written.
380  */
381 static int
382 __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
383                    int convertlf, int may_fail)
384 {
385         unsigned long flags;
386         void *page;
387         int written;
388         int overall_written;
389
390         if (count <= 0)
391                 return 0;
392         overall_written = 0;
393         spin_lock_irqsave(&sclp_vt220_lock, flags);
394         do {
395                 /* Create an sclp output buffer if none exists yet */
396                 if (sclp_vt220_current_request == NULL) {
397                         while (list_empty(&sclp_vt220_empty)) {
398                                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
399                                 if (may_fail)
400                                         goto out;
401                                 else
402                                         sclp_sync_wait();
403                                 spin_lock_irqsave(&sclp_vt220_lock, flags);
404                         }
405                         page = (void *) sclp_vt220_empty.next;
406                         list_del((struct list_head *) page);
407                         sclp_vt220_current_request =
408                                 sclp_vt220_initialize_page(page);
409                 }
410                 /* Try to write the string to the current request buffer */
411                 written = sclp_vt220_add_msg(sclp_vt220_current_request,
412                                              buf, count, convertlf);
413                 overall_written += written;
414                 if (written == count)
415                         break;
416                 /*
417                  * Not all characters could be written to the current
418                  * output buffer. Emit the buffer, create a new buffer
419                  * and then output the rest of the string.
420                  */
421                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
422                 sclp_vt220_emit_current();
423                 spin_lock_irqsave(&sclp_vt220_lock, flags);
424                 buf += written;
425                 count -= written;
426         } while (count > 0);
427         /* Setup timer to output current console buffer after some time */
428         if (sclp_vt220_current_request != NULL &&
429             !timer_pending(&sclp_vt220_timer) && do_schedule) {
430                 sclp_vt220_timer.function = sclp_vt220_timeout;
431                 sclp_vt220_timer.data = 0UL;
432                 sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
433                 add_timer(&sclp_vt220_timer);
434         }
435         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
436 out:
437         return overall_written;
438 }
439
440 /*
441  * This routine is called by the kernel to write a series of
442  * characters to the tty device.  The characters may come from
443  * user space or kernel space.  This routine will return the
444  * number of characters actually accepted for writing.
445  */
446 static int
447 sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
448 {
449         return __sclp_vt220_write(buf, count, 1, 0, 1);
450 }
451
452 #define SCLP_VT220_SESSION_ENDED        0x01
453 #define SCLP_VT220_SESSION_STARTED      0x80
454 #define SCLP_VT220_SESSION_DATA         0x00
455
456 /*
457  * Called by the SCLP to report incoming event buffers.
458  */
459 static void
460 sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
461 {
462         char *buffer;
463         unsigned int count;
464
465         /* Ignore input if device is not open */
466         if (sclp_vt220_tty == NULL)
467                 return;
468
469         buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
470         count = evbuf->length - sizeof(struct evbuf_header);
471
472         switch (*buffer) {
473         case SCLP_VT220_SESSION_ENDED:
474         case SCLP_VT220_SESSION_STARTED:
475                 break;
476         case SCLP_VT220_SESSION_DATA:
477                 /* Send input to line discipline */
478                 buffer++;
479                 count--;
480                 tty_insert_flip_string(sclp_vt220_tty, buffer, count);
481                 tty_flip_buffer_push(sclp_vt220_tty);
482                 break;
483         }
484 }
485
486 /*
487  * This routine is called when a particular tty device is opened.
488  */
489 static int
490 sclp_vt220_open(struct tty_struct *tty, struct file *filp)
491 {
492         if (tty->count == 1) {
493                 sclp_vt220_tty = tty;
494                 tty->driver_data = kmalloc(SCLP_VT220_BUF_SIZE, GFP_KERNEL);
495                 if (tty->driver_data == NULL)
496                         return -ENOMEM;
497                 tty->low_latency = 0;
498         }
499         return 0;
500 }
501
502 /*
503  * This routine is called when a particular tty device is closed.
504  */
505 static void
506 sclp_vt220_close(struct tty_struct *tty, struct file *filp)
507 {
508         if (tty->count == 1) {
509                 sclp_vt220_tty = NULL;
510                 kfree(tty->driver_data);
511                 tty->driver_data = NULL;
512         }
513 }
514
515 /*
516  * This routine is called by the kernel to write a single
517  * character to the tty device.  If the kernel uses this routine,
518  * it must call the flush_chars() routine (if defined) when it is
519  * done stuffing characters into the driver.
520  */
521 static int
522 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
523 {
524         return __sclp_vt220_write(&ch, 1, 0, 0, 1);
525 }
526
527 /*
528  * This routine is called by the kernel after it has written a
529  * series of characters to the tty device using put_char().  
530  */
531 static void
532 sclp_vt220_flush_chars(struct tty_struct *tty)
533 {
534         if (sclp_vt220_outqueue_count == 0)
535                 sclp_vt220_emit_current();
536         else
537                 sclp_vt220_flush_later = 1;
538 }
539
540 /*
541  * This routine returns the numbers of characters the tty driver
542  * will accept for queuing to be written.  This number is subject
543  * to change as output buffers get emptied, or if the output flow
544  * control is acted.
545  */
546 static int
547 sclp_vt220_write_room(struct tty_struct *tty)
548 {
549         unsigned long flags;
550         struct list_head *l;
551         int count;
552
553         spin_lock_irqsave(&sclp_vt220_lock, flags);
554         count = 0;
555         if (sclp_vt220_current_request != NULL)
556                 count = sclp_vt220_space_left(sclp_vt220_current_request);
557         list_for_each(l, &sclp_vt220_empty)
558                 count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
559         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
560         return count;
561 }
562
563 /*
564  * Return number of buffered chars.
565  */
566 static int
567 sclp_vt220_chars_in_buffer(struct tty_struct *tty)
568 {
569         unsigned long flags;
570         struct list_head *l;
571         struct sclp_vt220_request *r;
572         int count;
573
574         spin_lock_irqsave(&sclp_vt220_lock, flags);
575         count = 0;
576         if (sclp_vt220_current_request != NULL)
577                 count = sclp_vt220_chars_stored(sclp_vt220_current_request);
578         list_for_each(l, &sclp_vt220_outqueue) {
579                 r = list_entry(l, struct sclp_vt220_request, list);
580                 count += sclp_vt220_chars_stored(r);
581         }
582         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
583         return count;
584 }
585
586 static void
587 __sclp_vt220_flush_buffer(void)
588 {
589         unsigned long flags;
590
591         sclp_vt220_emit_current();
592         spin_lock_irqsave(&sclp_vt220_lock, flags);
593         if (timer_pending(&sclp_vt220_timer))
594                 del_timer(&sclp_vt220_timer);
595         while (sclp_vt220_outqueue_count > 0) {
596                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
597                 sclp_sync_wait();
598                 spin_lock_irqsave(&sclp_vt220_lock, flags);
599         }
600         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
601 }
602
603 /*
604  * Pass on all buffers to the hardware. Return only when there are no more
605  * buffers pending.
606  */
607 static void
608 sclp_vt220_flush_buffer(struct tty_struct *tty)
609 {
610         sclp_vt220_emit_current();
611 }
612
613 /* Release allocated pages. */
614 static void __init __sclp_vt220_free_pages(void)
615 {
616         struct list_head *page, *p;
617
618         list_for_each_safe(page, p, &sclp_vt220_empty) {
619                 list_del(page);
620                 if (slab_is_available())
621                         free_page((unsigned long) page);
622                 else
623                         free_bootmem((unsigned long) page, PAGE_SIZE);
624         }
625 }
626
627 /* Release memory and unregister from sclp core. Controlled by init counting -
628  * only the last invoker will actually perform these actions. */
629 static void __init __sclp_vt220_cleanup(void)
630 {
631         sclp_vt220_init_count--;
632         if (sclp_vt220_init_count != 0)
633                 return;
634         sclp_unregister(&sclp_vt220_register);
635         __sclp_vt220_free_pages();
636 }
637
638 /* Allocate buffer pages and register with sclp core. Controlled by init
639  * counting - only the first invoker will actually perform these actions. */
640 static int __init __sclp_vt220_init(int num_pages)
641 {
642         void *page;
643         int i;
644         int rc;
645
646         sclp_vt220_init_count++;
647         if (sclp_vt220_init_count != 1)
648                 return 0;
649         spin_lock_init(&sclp_vt220_lock);
650         INIT_LIST_HEAD(&sclp_vt220_empty);
651         INIT_LIST_HEAD(&sclp_vt220_outqueue);
652         init_timer(&sclp_vt220_timer);
653         sclp_vt220_current_request = NULL;
654         sclp_vt220_buffered_chars = 0;
655         sclp_vt220_outqueue_count = 0;
656         sclp_vt220_tty = NULL;
657         sclp_vt220_flush_later = 0;
658
659         /* Allocate pages for output buffering */
660         for (i = 0; i < num_pages; i++) {
661                 if (slab_is_available())
662                         page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
663                 else
664                         page = alloc_bootmem_low_pages(PAGE_SIZE);
665                 if (!page) {
666                         rc = -ENOMEM;
667                         goto out;
668                 }
669                 list_add_tail((struct list_head *) page, &sclp_vt220_empty);
670         }
671         rc = sclp_register(&sclp_vt220_register);
672 out:
673         if (rc) {
674                 __sclp_vt220_free_pages();
675                 sclp_vt220_init_count--;
676         }
677         return rc;
678 }
679
680 static const struct tty_operations sclp_vt220_ops = {
681         .open = sclp_vt220_open,
682         .close = sclp_vt220_close,
683         .write = sclp_vt220_write,
684         .put_char = sclp_vt220_put_char,
685         .flush_chars = sclp_vt220_flush_chars,
686         .write_room = sclp_vt220_write_room,
687         .chars_in_buffer = sclp_vt220_chars_in_buffer,
688         .flush_buffer = sclp_vt220_flush_buffer,
689 };
690
691 /*
692  * Register driver with SCLP and Linux and initialize internal tty structures.
693  */
694 static int __init sclp_vt220_tty_init(void)
695 {
696         struct tty_driver *driver;
697         int rc;
698
699         /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
700          * symmetry between VM and LPAR systems regarding ttyS1. */
701         driver = alloc_tty_driver(1);
702         if (!driver)
703                 return -ENOMEM;
704         rc = __sclp_vt220_init(MAX_KMEM_PAGES);
705         if (rc)
706                 goto out_driver;
707
708         driver->owner = THIS_MODULE;
709         driver->driver_name = SCLP_VT220_DRIVER_NAME;
710         driver->name = SCLP_VT220_DEVICE_NAME;
711         driver->major = SCLP_VT220_MAJOR;
712         driver->minor_start = SCLP_VT220_MINOR;
713         driver->type = TTY_DRIVER_TYPE_SYSTEM;
714         driver->subtype = SYSTEM_TYPE_TTY;
715         driver->init_termios = tty_std_termios;
716         driver->flags = TTY_DRIVER_REAL_RAW;
717         tty_set_operations(driver, &sclp_vt220_ops);
718
719         rc = tty_register_driver(driver);
720         if (rc)
721                 goto out_init;
722         sclp_vt220_driver = driver;
723         return 0;
724
725 out_init:
726         __sclp_vt220_cleanup();
727 out_driver:
728         put_tty_driver(driver);
729         return rc;
730 }
731 __initcall(sclp_vt220_tty_init);
732
733 #ifdef CONFIG_SCLP_VT220_CONSOLE
734
735 static void
736 sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
737 {
738         __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
739 }
740
741 static struct tty_driver *
742 sclp_vt220_con_device(struct console *c, int *index)
743 {
744         *index = 0;
745         return sclp_vt220_driver;
746 }
747
748 static int
749 sclp_vt220_notify(struct notifier_block *self,
750                           unsigned long event, void *data)
751 {
752         __sclp_vt220_flush_buffer();
753         return NOTIFY_OK;
754 }
755
756 static struct notifier_block on_panic_nb = {
757         .notifier_call = sclp_vt220_notify,
758         .priority = 1,
759 };
760
761 static struct notifier_block on_reboot_nb = {
762         .notifier_call = sclp_vt220_notify,
763         .priority = 1,
764 };
765
766 /* Structure needed to register with printk */
767 static struct console sclp_vt220_console =
768 {
769         .name = SCLP_VT220_CONSOLE_NAME,
770         .write = sclp_vt220_con_write,
771         .device = sclp_vt220_con_device,
772         .flags = CON_PRINTBUFFER,
773         .index = SCLP_VT220_CONSOLE_INDEX
774 };
775
776 static int __init
777 sclp_vt220_con_init(void)
778 {
779         int rc;
780
781         if (!CONSOLE_IS_SCLP)
782                 return 0;
783         rc = __sclp_vt220_init(MAX_CONSOLE_PAGES);
784         if (rc)
785                 return rc;
786         /* Attach linux console */
787         atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
788         register_reboot_notifier(&on_reboot_nb);
789         register_console(&sclp_vt220_console);
790         return 0;
791 }
792
793 console_initcall(sclp_vt220_con_init);
794 #endif /* CONFIG_SCLP_VT220_CONSOLE */
795