1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SCLP VT220 terminal driver.
4 *
5 * Copyright IBM Corp. 2003, 2009
6 *
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/panic_notifier.h>
13#include <linux/list.h>
14#include <linux/wait.h>
15#include <linux/timer.h>
16#include <linux/kernel.h>
17#include <linux/sysrq.h>
18#include <linux/tty.h>
19#include <linux/tty_driver.h>
20#include <linux/tty_flip.h>
21#include <linux/errno.h>
22#include <linux/mm.h>
23#include <linux/major.h>
24#include <linux/console.h>
25#include <linux/kdev_t.h>
26#include <linux/interrupt.h>
27#include <linux/init.h>
28#include <linux/reboot.h>
29#include <linux/slab.h>
30
31#include <linux/uaccess.h>
32#include "sclp.h"
33#include "ctrlchar.h"
34
35#define SCLP_VT220_MAJOR TTY_MAJOR
36#define SCLP_VT220_MINOR 65
37#define SCLP_VT220_DRIVER_NAME "sclp_vt220"
38#define SCLP_VT220_DEVICE_NAME "ttysclp"
39#define SCLP_VT220_CONSOLE_NAME "ttysclp"
40#define SCLP_VT220_CONSOLE_INDEX 0 /* console=ttysclp0 */
41
42/* Representation of a single write request */
43struct sclp_vt220_request {
44 struct list_head list;
45 struct sclp_req sclp_req;
46 int retry_count;
47};
48
49/* VT220 SCCB */
50struct sclp_vt220_sccb {
51 struct sccb_header header;
52 struct evbuf_header evbuf;
53};
54
55#define SCLP_VT220_MAX_CHARS_PER_BUFFER (PAGE_SIZE - \
56 sizeof(struct sclp_vt220_request) - \
57 sizeof(struct sclp_vt220_sccb))
58
59/* Structures and data needed to register tty driver */
60static struct tty_driver *sclp_vt220_driver;
61
62static struct tty_port sclp_vt220_port;
63
64/* Lock to protect internal data from concurrent access */
65static DEFINE_SPINLOCK(sclp_vt220_lock);
66
67/* List of empty pages to be used as write request buffers */
68static LIST_HEAD(sclp_vt220_empty);
69
70/* List of pending requests */
71static LIST_HEAD(sclp_vt220_outqueue);
72
73/* Flag that output queue is currently running */
74static int sclp_vt220_queue_running;
75
76/* Timer used for delaying write requests to merge subsequent messages into
77 * a single buffer */
78static struct timer_list sclp_vt220_timer;
79
80/* Pointer to current request buffer which has been partially filled but not
81 * yet sent */
82static struct sclp_vt220_request *sclp_vt220_current_request;
83
84/* Number of characters in current request buffer */
85static int sclp_vt220_buffered_chars;
86
87/* Counter controlling core driver initialization. */
88static int __initdata sclp_vt220_init_count;
89
90/* Flag indicating that sclp_vt220_current_request should really
91 * have been already queued but wasn't because the SCLP was processing
92 * another buffer */
93static int sclp_vt220_flush_later;
94
95static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
96static int __sclp_vt220_emit(struct sclp_vt220_request *request);
97static void sclp_vt220_emit_current(void);
98
99/* Registration structure for SCLP output event buffers */
100static struct sclp_register sclp_vt220_register = {
101 .send_mask = EVTYP_VT220MSG_MASK,
102};
103
104/* Registration structure for SCLP input event buffers */
105static struct sclp_register sclp_vt220_register_input = {
106 .receive_mask = EVTYP_VT220MSG_MASK,
107 .receiver_fn = sclp_vt220_receiver_fn,
108};
109
110
111/*
112 * Put provided request buffer back into queue and check emit pending
113 * buffers if necessary.
114 */
115static void
116sclp_vt220_process_queue(struct sclp_vt220_request *request)
117{
118 unsigned long flags;
119 void *page;
120
121 do {
122 /* Put buffer back to list of empty buffers */
123 page = request->sclp_req.sccb;
124 spin_lock_irqsave(&sclp_vt220_lock, flags);
125 /* Move request from outqueue to empty queue */
126 list_del(entry: &request->list);
127 list_add_tail(new: (struct list_head *) page, head: &sclp_vt220_empty);
128 /* Check if there is a pending buffer on the out queue. */
129 request = NULL;
130 if (!list_empty(head: &sclp_vt220_outqueue))
131 request = list_entry(sclp_vt220_outqueue.next,
132 struct sclp_vt220_request, list);
133 if (!request) {
134 sclp_vt220_queue_running = 0;
135 spin_unlock_irqrestore(lock: &sclp_vt220_lock, flags);
136 break;
137 }
138 spin_unlock_irqrestore(lock: &sclp_vt220_lock, flags);
139 } while (__sclp_vt220_emit(request));
140 if (request == NULL && sclp_vt220_flush_later)
141 sclp_vt220_emit_current();
142 tty_port_tty_wakeup(port: &sclp_vt220_port);
143}
144
145#define SCLP_BUFFER_MAX_RETRY 1
146
147/*
148 * Callback through which the result of a write request is reported by the
149 * SCLP.
150 */
151static void
152sclp_vt220_callback(struct sclp_req *request, void *data)
153{
154 struct sclp_vt220_request *vt220_request;
155 struct sclp_vt220_sccb *sccb;
156
157 vt220_request = (struct sclp_vt220_request *) data;
158 if (request->status == SCLP_REQ_FAILED) {
159 sclp_vt220_process_queue(request: vt220_request);
160 return;
161 }
162 sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
163
164 /* Check SCLP response code and choose suitable action */
165 switch (sccb->header.response_code) {
166 case 0x0020 :
167 break;
168
169 case 0x05f0: /* Target resource in improper state */
170 break;
171
172 case 0x0340: /* Contained SCLP equipment check */
173 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
174 break;
175 /* Remove processed buffers and requeue rest */
176 if (sclp_remove_processed(sccb: (struct sccb_header *) sccb) > 0) {
177 /* Not all buffers were processed */
178 sccb->header.response_code = 0x0000;
179 vt220_request->sclp_req.status = SCLP_REQ_FILLED;
180 if (sclp_add_request(req: request) == 0)
181 return;
182 }
183 break;
184
185 case 0x0040: /* SCLP equipment check */
186 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
187 break;
188 sccb->header.response_code = 0x0000;
189 vt220_request->sclp_req.status = SCLP_REQ_FILLED;
190 if (sclp_add_request(req: request) == 0)
191 return;
192 break;
193
194 default:
195 break;
196 }
197 sclp_vt220_process_queue(request: vt220_request);
198}
199
200/*
201 * Emit vt220 request buffer to SCLP. Return zero on success, non-zero
202 * otherwise.
203 */
204static int
205__sclp_vt220_emit(struct sclp_vt220_request *request)
206{
207 request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
208 request->sclp_req.status = SCLP_REQ_FILLED;
209 request->sclp_req.callback = sclp_vt220_callback;
210 request->sclp_req.callback_data = (void *) request;
211
212 return sclp_add_request(req: &request->sclp_req);
213}
214
215/*
216 * Queue and emit current request.
217 */
218static void
219sclp_vt220_emit_current(void)
220{
221 unsigned long flags;
222 struct sclp_vt220_request *request;
223 struct sclp_vt220_sccb *sccb;
224
225 spin_lock_irqsave(&sclp_vt220_lock, flags);
226 if (sclp_vt220_current_request) {
227 sccb = (struct sclp_vt220_sccb *)
228 sclp_vt220_current_request->sclp_req.sccb;
229 /* Only emit buffers with content */
230 if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
231 list_add_tail(new: &sclp_vt220_current_request->list,
232 head: &sclp_vt220_outqueue);
233 sclp_vt220_current_request = NULL;
234 timer_delete(timer: &sclp_vt220_timer);
235 }
236 sclp_vt220_flush_later = 0;
237 }
238 if (sclp_vt220_queue_running)
239 goto out_unlock;
240 if (list_empty(head: &sclp_vt220_outqueue))
241 goto out_unlock;
242 request = list_first_entry(&sclp_vt220_outqueue,
243 struct sclp_vt220_request, list);
244 sclp_vt220_queue_running = 1;
245 spin_unlock_irqrestore(lock: &sclp_vt220_lock, flags);
246
247 if (__sclp_vt220_emit(request))
248 sclp_vt220_process_queue(request);
249 return;
250out_unlock:
251 spin_unlock_irqrestore(lock: &sclp_vt220_lock, flags);
252}
253
254#define SCLP_NORMAL_WRITE 0x00
255
256/*
257 * Helper function to initialize a page with the sclp request structure.
258 */
259static struct sclp_vt220_request *
260sclp_vt220_initialize_page(void *page)
261{
262 struct sclp_vt220_request *request;
263 struct sclp_vt220_sccb *sccb;
264
265 /* Place request structure at end of page */
266 request = ((struct sclp_vt220_request *)
267 ((addr_t) page + PAGE_SIZE)) - 1;
268 request->retry_count = 0;
269 request->sclp_req.sccb = page;
270 /* SCCB goes at start of page */
271 sccb = (struct sclp_vt220_sccb *) page;
272 memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
273 sccb->header.length = sizeof(struct sclp_vt220_sccb);
274 sccb->header.function_code = SCLP_NORMAL_WRITE;
275 sccb->header.response_code = 0x0000;
276 sccb->evbuf.type = EVTYP_VT220MSG;
277 sccb->evbuf.length = sizeof(struct evbuf_header);
278
279 return request;
280}
281
282static inline unsigned int
283sclp_vt220_space_left(struct sclp_vt220_request *request)
284{
285 struct sclp_vt220_sccb *sccb;
286 sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
287 return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
288 sccb->header.length;
289}
290
291static inline unsigned int
292sclp_vt220_chars_stored(struct sclp_vt220_request *request)
293{
294 struct sclp_vt220_sccb *sccb;
295 sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
296 return sccb->evbuf.length - sizeof(struct evbuf_header);
297}
298
299/*
300 * Add msg to buffer associated with request. Return the number of characters
301 * added.
302 */
303static int
304sclp_vt220_add_msg(struct sclp_vt220_request *request,
305 const unsigned char *msg, int count, int convertlf)
306{
307 struct sclp_vt220_sccb *sccb;
308 void *buffer;
309 unsigned char c;
310 int from;
311 int to;
312
313 if (count > sclp_vt220_space_left(request))
314 count = sclp_vt220_space_left(request);
315 if (count <= 0)
316 return 0;
317
318 sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
319 buffer = (void *) ((addr_t) sccb + sccb->header.length);
320
321 if (convertlf) {
322 /* Perform Linefeed conversion (0x0a -> 0x0d 0x0a)*/
323 for (from=0, to=0;
324 (from < count) && (to < sclp_vt220_space_left(request));
325 from++) {
326 /* Retrieve character */
327 c = msg[from];
328 /* Perform conversion */
329 if (c == 0x0a) {
330 if (to + 1 < sclp_vt220_space_left(request)) {
331 ((unsigned char *) buffer)[to++] = 0x0d;
332 ((unsigned char *) buffer)[to++] = c;
333 } else
334 break;
335
336 } else
337 ((unsigned char *) buffer)[to++] = c;
338 }
339 sccb->header.length += to;
340 sccb->evbuf.length += to;
341 return from;
342 } else {
343 memcpy(buffer, (const void *) msg, count);
344 sccb->header.length += count;
345 sccb->evbuf.length += count;
346 return count;
347 }
348}
349
350/*
351 * Emit buffer after having waited long enough for more data to arrive.
352 */
353static void
354sclp_vt220_timeout(struct timer_list *unused)
355{
356 sclp_vt220_emit_current();
357}
358
359#define BUFFER_MAX_DELAY HZ/20
360
361/*
362 * Drop oldest console buffer if sclp_con_drop is set
363 */
364static int
365sclp_vt220_drop_buffer(void)
366{
367 struct list_head *list;
368 struct sclp_vt220_request *request;
369 void *page;
370
371 if (!sclp_console_drop)
372 return 0;
373 list = sclp_vt220_outqueue.next;
374 if (sclp_vt220_queue_running)
375 /* The first element is in I/O */
376 list = list->next;
377 if (list == &sclp_vt220_outqueue)
378 return 0;
379 list_del(entry: list);
380 request = list_entry(list, struct sclp_vt220_request, list);
381 page = request->sclp_req.sccb;
382 list_add_tail(new: (struct list_head *) page, head: &sclp_vt220_empty);
383 return 1;
384}
385
386/*
387 * Internal implementation of the write function. Write COUNT bytes of data
388 * from memory at BUF
389 * to the SCLP interface. In case that the data does not fit into the current
390 * write buffer, emit the current one and allocate a new one. If there are no
391 * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
392 * is non-zero, the buffer will be scheduled for emitting after a timeout -
393 * otherwise the user has to explicitly call the flush function.
394 * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
395 * buffer should be converted to 0x0a 0x0d. After completion, return the number
396 * of bytes written.
397 */
398static int
399__sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
400 int convertlf, int may_fail)
401{
402 unsigned long flags;
403 void *page;
404 int written;
405 int overall_written;
406
407 if (count <= 0)
408 return 0;
409 overall_written = 0;
410 spin_lock_irqsave(&sclp_vt220_lock, flags);
411 do {
412 /* Create an sclp output buffer if none exists yet */
413 if (sclp_vt220_current_request == NULL) {
414 if (list_empty(head: &sclp_vt220_empty))
415 sclp_console_full++;
416 while (list_empty(head: &sclp_vt220_empty)) {
417 if (may_fail)
418 goto out;
419 if (sclp_vt220_drop_buffer())
420 break;
421 spin_unlock_irqrestore(lock: &sclp_vt220_lock, flags);
422
423 sclp_sync_wait();
424 spin_lock_irqsave(&sclp_vt220_lock, flags);
425 }
426 page = (void *) sclp_vt220_empty.next;
427 list_del(entry: (struct list_head *) page);
428 sclp_vt220_current_request =
429 sclp_vt220_initialize_page(page);
430 }
431 /* Try to write the string to the current request buffer */
432 written = sclp_vt220_add_msg(request: sclp_vt220_current_request,
433 msg: buf, count, convertlf);
434 overall_written += written;
435 if (written == count)
436 break;
437 /*
438 * Not all characters could be written to the current
439 * output buffer. Emit the buffer, create a new buffer
440 * and then output the rest of the string.
441 */
442 spin_unlock_irqrestore(lock: &sclp_vt220_lock, flags);
443 sclp_vt220_emit_current();
444 spin_lock_irqsave(&sclp_vt220_lock, flags);
445 buf += written;
446 count -= written;
447 } while (count > 0);
448 /* Setup timer to output current console buffer after some time */
449 if (sclp_vt220_current_request != NULL &&
450 !timer_pending(timer: &sclp_vt220_timer) && do_schedule) {
451 sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
452 add_timer(timer: &sclp_vt220_timer);
453 }
454out:
455 spin_unlock_irqrestore(lock: &sclp_vt220_lock, flags);
456 return overall_written;
457}
458
459/*
460 * This routine is called by the kernel to write a series of
461 * characters to the tty device. The characters may come from
462 * user space or kernel space. This routine will return the
463 * number of characters actually accepted for writing.
464 */
465static ssize_t
466sclp_vt220_write(struct tty_struct *tty, const u8 *buf, size_t count)
467{
468 return __sclp_vt220_write(buf, count, do_schedule: 1, convertlf: 0, may_fail: 1);
469}
470
471#define SCLP_VT220_SESSION_ENDED 0x01
472#define SCLP_VT220_SESSION_STARTED 0x80
473#define SCLP_VT220_SESSION_DATA 0x00
474
475#ifdef CONFIG_MAGIC_SYSRQ
476
477static int sysrq_pressed;
478static struct sysrq_work sysrq;
479
480static void sclp_vt220_reset_session(void)
481{
482 sysrq_pressed = 0;
483}
484
485static void sclp_vt220_handle_input(const char *buffer, unsigned int count)
486{
487 int i;
488
489 for (i = 0; i < count; i++) {
490 /* Handle magic sys request */
491 if (buffer[i] == ('O' ^ 0100)) { /* CTRL-O */
492 /*
493 * If pressed again, reset sysrq_pressed
494 * and flip CTRL-O character
495 */
496 sysrq_pressed = !sysrq_pressed;
497 if (sysrq_pressed)
498 continue;
499 } else if (sysrq_pressed) {
500 sysrq.key = buffer[i];
501 schedule_sysrq_work(sw: &sysrq);
502 sysrq_pressed = 0;
503 continue;
504 }
505 tty_insert_flip_char(port: &sclp_vt220_port, ch: buffer[i], flag: 0);
506 }
507}
508
509#else
510
511static void sclp_vt220_reset_session(void)
512{
513}
514
515static void sclp_vt220_handle_input(const char *buffer, unsigned int count)
516{
517 tty_insert_flip_string(&sclp_vt220_port, buffer, count);
518}
519
520#endif
521
522/*
523 * Called by the SCLP to report incoming event buffers.
524 */
525static void
526sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
527{
528 char *buffer;
529 unsigned int count;
530
531 buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
532 count = evbuf->length - sizeof(struct evbuf_header);
533
534 switch (*buffer) {
535 case SCLP_VT220_SESSION_ENDED:
536 case SCLP_VT220_SESSION_STARTED:
537 sclp_vt220_reset_session();
538 break;
539 case SCLP_VT220_SESSION_DATA:
540 /* Send input to line discipline */
541 buffer++;
542 count--;
543 sclp_vt220_handle_input(buffer, count);
544 tty_flip_buffer_push(port: &sclp_vt220_port);
545 break;
546 }
547}
548
549/*
550 * This routine is called when a particular tty device is opened.
551 */
552static int
553sclp_vt220_open(struct tty_struct *tty, struct file *filp)
554{
555 if (tty->count == 1) {
556 tty_port_tty_set(port: &sclp_vt220_port, tty);
557 if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
558 tty->winsize.ws_row = 24;
559 tty->winsize.ws_col = 80;
560 }
561 }
562 return 0;
563}
564
565/*
566 * This routine is called when a particular tty device is closed.
567 */
568static void
569sclp_vt220_close(struct tty_struct *tty, struct file *filp)
570{
571 if (tty->count == 1)
572 tty_port_tty_set(port: &sclp_vt220_port, NULL);
573}
574
575/*
576 * This routine is called by the kernel to write a single
577 * character to the tty device. If the kernel uses this routine,
578 * it must call the flush_chars() routine (if defined) when it is
579 * done stuffing characters into the driver.
580 */
581static int
582sclp_vt220_put_char(struct tty_struct *tty, u8 ch)
583{
584 return __sclp_vt220_write(buf: &ch, count: 1, do_schedule: 0, convertlf: 0, may_fail: 1);
585}
586
587/*
588 * This routine is called by the kernel after it has written a
589 * series of characters to the tty device using put_char().
590 */
591static void
592sclp_vt220_flush_chars(struct tty_struct *tty)
593{
594 if (!sclp_vt220_queue_running)
595 sclp_vt220_emit_current();
596 else
597 sclp_vt220_flush_later = 1;
598}
599
600/*
601 * This routine returns the numbers of characters the tty driver
602 * will accept for queuing to be written. This number is subject
603 * to change as output buffers get emptied, or if the output flow
604 * control is acted.
605 */
606static unsigned int
607sclp_vt220_write_room(struct tty_struct *tty)
608{
609 unsigned long flags;
610 struct list_head *l;
611 unsigned int count;
612
613 spin_lock_irqsave(&sclp_vt220_lock, flags);
614 count = 0;
615 if (sclp_vt220_current_request != NULL)
616 count = sclp_vt220_space_left(request: sclp_vt220_current_request);
617 list_for_each(l, &sclp_vt220_empty)
618 count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
619 spin_unlock_irqrestore(lock: &sclp_vt220_lock, flags);
620 return count;
621}
622
623/*
624 * Return number of buffered chars.
625 */
626static unsigned int
627sclp_vt220_chars_in_buffer(struct tty_struct *tty)
628{
629 unsigned long flags;
630 struct list_head *l;
631 struct sclp_vt220_request *r;
632 unsigned int count = 0;
633
634 spin_lock_irqsave(&sclp_vt220_lock, flags);
635 if (sclp_vt220_current_request != NULL)
636 count = sclp_vt220_chars_stored(request: sclp_vt220_current_request);
637 list_for_each(l, &sclp_vt220_outqueue) {
638 r = list_entry(l, struct sclp_vt220_request, list);
639 count += sclp_vt220_chars_stored(request: r);
640 }
641 spin_unlock_irqrestore(lock: &sclp_vt220_lock, flags);
642 return count;
643}
644
645/*
646 * Pass on all buffers to the hardware. Return only when there are no more
647 * buffers pending.
648 */
649static void
650sclp_vt220_flush_buffer(struct tty_struct *tty)
651{
652 sclp_vt220_emit_current();
653}
654
655/* Release allocated pages. */
656static void __init __sclp_vt220_free_pages(void)
657{
658 struct list_head *page, *p;
659
660 list_for_each_safe(page, p, &sclp_vt220_empty) {
661 list_del(entry: page);
662 free_page((unsigned long) page);
663 }
664}
665
666/* Release memory and unregister from sclp core. Controlled by init counting -
667 * only the last invoker will actually perform these actions. */
668static void __init __sclp_vt220_cleanup(void)
669{
670 sclp_vt220_init_count--;
671 if (sclp_vt220_init_count != 0)
672 return;
673 sclp_unregister(reg: &sclp_vt220_register);
674 __sclp_vt220_free_pages();
675 tty_port_destroy(port: &sclp_vt220_port);
676}
677
678/* Allocate buffer pages and register with sclp core. Controlled by init
679 * counting - only the first invoker will actually perform these actions. */
680static int __init __sclp_vt220_init(int num_pages)
681{
682 void *page;
683 int i;
684 int rc;
685
686 sclp_vt220_init_count++;
687 if (sclp_vt220_init_count != 1)
688 return 0;
689 timer_setup(&sclp_vt220_timer, sclp_vt220_timeout, 0);
690 tty_port_init(port: &sclp_vt220_port);
691 sclp_vt220_current_request = NULL;
692 sclp_vt220_buffered_chars = 0;
693 sclp_vt220_flush_later = 0;
694
695 /* Allocate pages for output buffering */
696 rc = -ENOMEM;
697 for (i = 0; i < num_pages; i++) {
698 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
699 if (!page)
700 goto out;
701 list_add_tail(new: page, head: &sclp_vt220_empty);
702 }
703 rc = sclp_register(reg: &sclp_vt220_register);
704out:
705 if (rc) {
706 __sclp_vt220_free_pages();
707 sclp_vt220_init_count--;
708 tty_port_destroy(port: &sclp_vt220_port);
709 }
710 return rc;
711}
712
713static const struct tty_operations sclp_vt220_ops = {
714 .open = sclp_vt220_open,
715 .close = sclp_vt220_close,
716 .write = sclp_vt220_write,
717 .put_char = sclp_vt220_put_char,
718 .flush_chars = sclp_vt220_flush_chars,
719 .write_room = sclp_vt220_write_room,
720 .chars_in_buffer = sclp_vt220_chars_in_buffer,
721 .flush_buffer = sclp_vt220_flush_buffer,
722};
723
724/*
725 * Register driver with SCLP and Linux and initialize internal tty structures.
726 */
727static int __init sclp_vt220_tty_init(void)
728{
729 struct tty_driver *driver;
730 int rc;
731
732 /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
733 * symmetry between VM and LPAR systems regarding ttyS1. */
734 driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW);
735 if (IS_ERR(ptr: driver))
736 return PTR_ERR(ptr: driver);
737 rc = __sclp_vt220_init(MAX_KMEM_PAGES);
738 if (rc)
739 goto out_driver;
740
741 driver->driver_name = SCLP_VT220_DRIVER_NAME;
742 driver->name = SCLP_VT220_DEVICE_NAME;
743 driver->major = SCLP_VT220_MAJOR;
744 driver->minor_start = SCLP_VT220_MINOR;
745 driver->type = TTY_DRIVER_TYPE_SYSTEM;
746 driver->subtype = SYSTEM_TYPE_TTY;
747 driver->init_termios = tty_std_termios;
748 tty_set_operations(driver, op: &sclp_vt220_ops);
749 tty_port_link_device(port: &sclp_vt220_port, driver, index: 0);
750
751 rc = tty_register_driver(driver);
752 if (rc)
753 goto out_init;
754 rc = sclp_register(reg: &sclp_vt220_register_input);
755 if (rc)
756 goto out_reg;
757 sclp_vt220_driver = driver;
758 return 0;
759
760out_reg:
761 tty_unregister_driver(driver);
762out_init:
763 __sclp_vt220_cleanup();
764out_driver:
765 tty_driver_kref_put(driver);
766 return rc;
767}
768__initcall(sclp_vt220_tty_init);
769
770#ifdef CONFIG_SCLP_VT220_CONSOLE
771
772static void
773sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
774{
775 __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
776}
777
778static struct tty_driver *
779sclp_vt220_con_device(struct console *c, int *index)
780{
781 *index = 0;
782 return sclp_vt220_driver;
783}
784
785/*
786 * This panic/reboot notifier runs in atomic context, so
787 * locking restrictions apply to prevent potential lockups.
788 */
789static int
790sclp_vt220_notify(struct notifier_block *self,
791 unsigned long event, void *data)
792{
793 unsigned long flags;
794
795 if (spin_is_locked(&sclp_vt220_lock))
796 return NOTIFY_DONE;
797
798 sclp_vt220_emit_current();
799
800 spin_lock_irqsave(&sclp_vt220_lock, flags);
801 timer_delete(&sclp_vt220_timer);
802 while (sclp_vt220_queue_running) {
803 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
804 sclp_sync_wait();
805 spin_lock_irqsave(&sclp_vt220_lock, flags);
806 }
807 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
808
809 return NOTIFY_DONE;
810}
811
812static struct notifier_block on_panic_nb = {
813 .notifier_call = sclp_vt220_notify,
814 .priority = INT_MIN + 1, /* run the callback late */
815};
816
817static struct notifier_block on_reboot_nb = {
818 .notifier_call = sclp_vt220_notify,
819 .priority = INT_MIN + 1, /* run the callback late */
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

source code of linux/drivers/s390/char/sclp_vt220.c