Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux...
[linux-2.6] / drivers / s390 / char / sclp_tty.c
1 /*
2  *  drivers/s390/char/sclp_tty.c
3  *    SCLP line mode terminal driver.
4  *
5  *  S390 version
6  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
7  *    Author(s): Martin Peschke <mpeschke@de.ibm.com>
8  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
9  */
10
11 #include <linux/module.h>
12 #include <linux/kmod.h>
13 #include <linux/tty.h>
14 #include <linux/tty_driver.h>
15 #include <linux/tty_flip.h>
16 #include <linux/slab.h>
17 #include <linux/err.h>
18 #include <linux/init.h>
19 #include <linux/interrupt.h>
20 #include <asm/uaccess.h>
21
22 #include "ctrlchar.h"
23 #include "sclp.h"
24 #include "sclp_rw.h"
25 #include "sclp_tty.h"
26
27 /*
28  * size of a buffer that collects single characters coming in
29  * via sclp_tty_put_char()
30  */
31 #define SCLP_TTY_BUF_SIZE 512
32
33 /*
34  * There is exactly one SCLP terminal, so we can keep things simple
35  * and allocate all variables statically.
36  */
37
38 /* Lock to guard over changes to global variables. */
39 static spinlock_t sclp_tty_lock;
40 /* List of free pages that can be used for console output buffering. */
41 static struct list_head sclp_tty_pages;
42 /* List of full struct sclp_buffer structures ready for output. */
43 static struct list_head sclp_tty_outqueue;
44 /* Counter how many buffers are emitted. */
45 static int sclp_tty_buffer_count;
46 /* Pointer to current console buffer. */
47 static struct sclp_buffer *sclp_ttybuf;
48 /* Timer for delayed output of console messages. */
49 static struct timer_list sclp_tty_timer;
50
51 static struct tty_struct *sclp_tty;
52 static unsigned char sclp_tty_chars[SCLP_TTY_BUF_SIZE];
53 static unsigned short int sclp_tty_chars_count;
54
55 struct tty_driver *sclp_tty_driver;
56
57 static int sclp_tty_tolower;
58 static int sclp_tty_columns = 80;
59
60 #define SPACES_PER_TAB 8
61 #define CASE_DELIMITER 0x6c /* to separate upper and lower case (% in EBCDIC) */
62
63 /* This routine is called whenever we try to open a SCLP terminal. */
64 static int
65 sclp_tty_open(struct tty_struct *tty, struct file *filp)
66 {
67         sclp_tty = tty;
68         tty->driver_data = NULL;
69         tty->low_latency = 0;
70         return 0;
71 }
72
73 /* This routine is called when the SCLP terminal is closed. */
74 static void
75 sclp_tty_close(struct tty_struct *tty, struct file *filp)
76 {
77         if (tty->count > 1)
78                 return;
79         sclp_tty = NULL;
80 }
81
82 /*
83  * This routine returns the numbers of characters the tty driver
84  * will accept for queuing to be written.  This number is subject
85  * to change as output buffers get emptied, or if the output flow
86  * control is acted. This is not an exact number because not every
87  * character needs the same space in the sccb. The worst case is
88  * a string of newlines. Every newlines creates a new mto which
89  * needs 8 bytes.
90  */
91 static int
92 sclp_tty_write_room (struct tty_struct *tty)
93 {
94         unsigned long flags;
95         struct list_head *l;
96         int count;
97
98         spin_lock_irqsave(&sclp_tty_lock, flags);
99         count = 0;
100         if (sclp_ttybuf != NULL)
101                 count = sclp_buffer_space(sclp_ttybuf) / sizeof(struct mto);
102         list_for_each(l, &sclp_tty_pages)
103                 count += NR_EMPTY_MTO_PER_SCCB;
104         spin_unlock_irqrestore(&sclp_tty_lock, flags);
105         return count;
106 }
107
108 static void
109 sclp_ttybuf_callback(struct sclp_buffer *buffer, int rc)
110 {
111         unsigned long flags;
112         void *page;
113
114         do {
115                 page = sclp_unmake_buffer(buffer);
116                 spin_lock_irqsave(&sclp_tty_lock, flags);
117                 /* Remove buffer from outqueue */
118                 list_del(&buffer->list);
119                 sclp_tty_buffer_count--;
120                 list_add_tail((struct list_head *) page, &sclp_tty_pages);
121                 /* Check if there is a pending buffer on the out queue. */
122                 buffer = NULL;
123                 if (!list_empty(&sclp_tty_outqueue))
124                         buffer = list_entry(sclp_tty_outqueue.next,
125                                             struct sclp_buffer, list);
126                 spin_unlock_irqrestore(&sclp_tty_lock, flags);
127         } while (buffer && sclp_emit_buffer(buffer, sclp_ttybuf_callback));
128         /* check if the tty needs a wake up call */
129         if (sclp_tty != NULL) {
130                 tty_wakeup(sclp_tty);
131         }
132 }
133
134 static inline void
135 __sclp_ttybuf_emit(struct sclp_buffer *buffer)
136 {
137         unsigned long flags;
138         int count;
139         int rc;
140
141         spin_lock_irqsave(&sclp_tty_lock, flags);
142         list_add_tail(&buffer->list, &sclp_tty_outqueue);
143         count = sclp_tty_buffer_count++;
144         spin_unlock_irqrestore(&sclp_tty_lock, flags);
145         if (count)
146                 return;
147         rc = sclp_emit_buffer(buffer, sclp_ttybuf_callback);
148         if (rc)
149                 sclp_ttybuf_callback(buffer, rc);
150 }
151
152 /*
153  * When this routine is called from the timer then we flush the
154  * temporary write buffer.
155  */
156 static void
157 sclp_tty_timeout(unsigned long data)
158 {
159         unsigned long flags;
160         struct sclp_buffer *buf;
161
162         spin_lock_irqsave(&sclp_tty_lock, flags);
163         buf = sclp_ttybuf;
164         sclp_ttybuf = NULL;
165         spin_unlock_irqrestore(&sclp_tty_lock, flags);
166
167         if (buf != NULL) {
168                 __sclp_ttybuf_emit(buf);
169         }
170 }
171
172 /*
173  * Write a string to the sclp tty.
174  */
175 static int sclp_tty_write_string(const unsigned char *str, int count, int may_fail)
176 {
177         unsigned long flags;
178         void *page;
179         int written;
180         int overall_written;
181         struct sclp_buffer *buf;
182
183         if (count <= 0)
184                 return 0;
185         overall_written = 0;
186         spin_lock_irqsave(&sclp_tty_lock, flags);
187         do {
188                 /* Create a sclp output buffer if none exists yet */
189                 if (sclp_ttybuf == NULL) {
190                         while (list_empty(&sclp_tty_pages)) {
191                                 spin_unlock_irqrestore(&sclp_tty_lock, flags);
192                                 if (may_fail)
193                                         goto out;
194                                 else
195                                         sclp_sync_wait();
196                                 spin_lock_irqsave(&sclp_tty_lock, flags);
197                         }
198                         page = sclp_tty_pages.next;
199                         list_del((struct list_head *) page);
200                         sclp_ttybuf = sclp_make_buffer(page, sclp_tty_columns,
201                                                        SPACES_PER_TAB);
202                 }
203                 /* try to write the string to the current output buffer */
204                 written = sclp_write(sclp_ttybuf, str, count);
205                 overall_written += written;
206                 if (written == count)
207                         break;
208                 /*
209                  * Not all characters could be written to the current
210                  * output buffer. Emit the buffer, create a new buffer
211                  * and then output the rest of the string.
212                  */
213                 buf = sclp_ttybuf;
214                 sclp_ttybuf = NULL;
215                 spin_unlock_irqrestore(&sclp_tty_lock, flags);
216                 __sclp_ttybuf_emit(buf);
217                 spin_lock_irqsave(&sclp_tty_lock, flags);
218                 str += written;
219                 count -= written;
220         } while (count > 0);
221         /* Setup timer to output current console buffer after 1/10 second */
222         if (sclp_ttybuf && sclp_chars_in_buffer(sclp_ttybuf) &&
223             !timer_pending(&sclp_tty_timer)) {
224                 init_timer(&sclp_tty_timer);
225                 sclp_tty_timer.function = sclp_tty_timeout;
226                 sclp_tty_timer.data = 0UL;
227                 sclp_tty_timer.expires = jiffies + HZ/10;
228                 add_timer(&sclp_tty_timer);
229         }
230         spin_unlock_irqrestore(&sclp_tty_lock, flags);
231 out:
232         return overall_written;
233 }
234
235 /*
236  * This routine is called by the kernel to write a series of characters to the
237  * tty device. The characters may come from user space or kernel space. This
238  * routine will return the number of characters actually accepted for writing.
239  */
240 static int
241 sclp_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
242 {
243         if (sclp_tty_chars_count > 0) {
244                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);
245                 sclp_tty_chars_count = 0;
246         }
247         return sclp_tty_write_string(buf, count, 1);
248 }
249
250 /*
251  * This routine is called by the kernel to write a single character to the tty
252  * device. If the kernel uses this routine, it must call the flush_chars()
253  * routine (if defined) when it is done stuffing characters into the driver.
254  *
255  * Characters provided to sclp_tty_put_char() are buffered by the SCLP driver.
256  * If the given character is a '\n' the contents of the SCLP write buffer
257  * - including previous characters from sclp_tty_put_char() and strings from
258  * sclp_write() without final '\n' - will be written.
259  */
260 static int
261 sclp_tty_put_char(struct tty_struct *tty, unsigned char ch)
262 {
263         sclp_tty_chars[sclp_tty_chars_count++] = ch;
264         if (ch == '\n' || sclp_tty_chars_count >= SCLP_TTY_BUF_SIZE) {
265                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);
266                 sclp_tty_chars_count = 0;
267         }
268         return 1;
269 }
270
271 /*
272  * This routine is called by the kernel after it has written a series of
273  * characters to the tty device using put_char().
274  */
275 static void
276 sclp_tty_flush_chars(struct tty_struct *tty)
277 {
278         if (sclp_tty_chars_count > 0) {
279                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);
280                 sclp_tty_chars_count = 0;
281         }
282 }
283
284 /*
285  * This routine returns the number of characters in the write buffer of the
286  * SCLP driver. The provided number includes all characters that are stored
287  * in the SCCB (will be written next time the SCLP is not busy) as well as
288  * characters in the write buffer (will not be written as long as there is a
289  * final line feed missing).
290  */
291 static int
292 sclp_tty_chars_in_buffer(struct tty_struct *tty)
293 {
294         unsigned long flags;
295         struct list_head *l;
296         struct sclp_buffer *t;
297         int count;
298
299         spin_lock_irqsave(&sclp_tty_lock, flags);
300         count = 0;
301         if (sclp_ttybuf != NULL)
302                 count = sclp_chars_in_buffer(sclp_ttybuf);
303         list_for_each(l, &sclp_tty_outqueue) {
304                 t = list_entry(l, struct sclp_buffer, list);
305                 count += sclp_chars_in_buffer(t);
306         }
307         spin_unlock_irqrestore(&sclp_tty_lock, flags);
308         return count;
309 }
310
311 /*
312  * removes all content from buffers of low level driver
313  */
314 static void
315 sclp_tty_flush_buffer(struct tty_struct *tty)
316 {
317         if (sclp_tty_chars_count > 0) {
318                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);
319                 sclp_tty_chars_count = 0;
320         }
321 }
322
323 /*
324  * push input to tty
325  */
326 static void
327 sclp_tty_input(unsigned char* buf, unsigned int count)
328 {
329         unsigned int cchar;
330
331         /*
332          * If this tty driver is currently closed
333          * then throw the received input away.
334          */
335         if (sclp_tty == NULL)
336                 return;
337         cchar = ctrlchar_handle(buf, count, sclp_tty);
338         switch (cchar & CTRLCHAR_MASK) {
339         case CTRLCHAR_SYSRQ:
340                 break;
341         case CTRLCHAR_CTRL:
342                 tty_insert_flip_char(sclp_tty, cchar, TTY_NORMAL);
343                 tty_flip_buffer_push(sclp_tty);
344                 break;
345         case CTRLCHAR_NONE:
346                 /* send (normal) input to line discipline */
347                 if (count < 2 ||
348                     (strncmp((const char *) buf + count - 2, "^n", 2) &&
349                      strncmp((const char *) buf + count - 2, "\252n", 2))) {
350                         /* add the auto \n */
351                         tty_insert_flip_string(sclp_tty, buf, count);
352                         tty_insert_flip_char(sclp_tty, '\n', TTY_NORMAL);
353                 } else
354                         tty_insert_flip_string(sclp_tty, buf, count - 2);
355                 tty_flip_buffer_push(sclp_tty);
356                 break;
357         }
358 }
359
360 /*
361  * get a EBCDIC string in upper/lower case,
362  * find out characters in lower/upper case separated by a special character,
363  * modifiy original string,
364  * returns length of resulting string
365  */
366 static int sclp_switch_cases(unsigned char *buf, int count)
367 {
368         unsigned char *ip, *op;
369         int toggle;
370
371         /* initially changing case is off */
372         toggle = 0;
373         ip = op = buf;
374         while (count-- > 0) {
375                 /* compare with special character */
376                 if (*ip == CASE_DELIMITER) {
377                         /* followed by another special character? */
378                         if (count && ip[1] == CASE_DELIMITER) {
379                                 /*
380                                  * ... then put a single copy of the special
381                                  * character to the output string
382                                  */
383                                 *op++ = *ip++;
384                                 count--;
385                         } else
386                                 /*
387                                  * ... special character follower by a normal
388                                  * character toggles the case change behaviour
389                                  */
390                                 toggle = ~toggle;
391                         /* skip special character */
392                         ip++;
393                 } else
394                         /* not the special character */
395                         if (toggle)
396                                 /* but case switching is on */
397                                 if (sclp_tty_tolower)
398                                         /* switch to uppercase */
399                                         *op++ = _ebc_toupper[(int) *ip++];
400                                 else
401                                         /* switch to lowercase */
402                                         *op++ = _ebc_tolower[(int) *ip++];
403                         else
404                                 /* no case switching, copy the character */
405                                 *op++ = *ip++;
406         }
407         /* return length of reformatted string. */
408         return op - buf;
409 }
410
411 static void
412 sclp_get_input(unsigned char *start, unsigned char *end)
413 {
414         int count;
415
416         count = end - start;
417         if (sclp_tty_tolower)
418                 EBC_TOLOWER(start, count);
419         count = sclp_switch_cases(start, count);
420         /* convert EBCDIC to ASCII (modify original input in SCCB) */
421         sclp_ebcasc_str(start, count);
422
423         /* transfer input to high level driver */
424         sclp_tty_input(start, count);
425 }
426
427 static inline struct gds_vector *
428 find_gds_vector(struct gds_vector *start, struct gds_vector *end, u16 id)
429 {
430         struct gds_vector *vec;
431
432         for (vec = start; vec < end; vec = (void *) vec + vec->length)
433                 if (vec->gds_id == id)
434                         return vec;
435         return NULL;
436 }
437
438 static inline struct gds_subvector *
439 find_gds_subvector(struct gds_subvector *start,
440                    struct gds_subvector *end, u8 key)
441 {
442         struct gds_subvector *subvec;
443
444         for (subvec = start; subvec < end;
445              subvec = (void *) subvec + subvec->length)
446                 if (subvec->key == key)
447                         return subvec;
448         return NULL;
449 }
450
451 static inline void
452 sclp_eval_selfdeftextmsg(struct gds_subvector *start,
453                          struct gds_subvector *end)
454 {
455         struct gds_subvector *subvec;
456
457         subvec = start;
458         while (subvec < end) {
459                 subvec = find_gds_subvector(subvec, end, 0x30);
460                 if (!subvec)
461                         break;
462                 sclp_get_input((unsigned char *)(subvec + 1),
463                                (unsigned char *) subvec + subvec->length);
464                 subvec = (void *) subvec + subvec->length;
465         }
466 }
467
468 static inline void
469 sclp_eval_textcmd(struct gds_subvector *start,
470                   struct gds_subvector *end)
471 {
472         struct gds_subvector *subvec;
473
474         subvec = start;
475         while (subvec < end) {
476                 subvec = find_gds_subvector(subvec, end,
477                                             GDS_KEY_SELFDEFTEXTMSG);
478                 if (!subvec)
479                         break;
480                 sclp_eval_selfdeftextmsg((struct gds_subvector *)(subvec + 1),
481                                          (void *)subvec + subvec->length);
482                 subvec = (void *) subvec + subvec->length;
483         }
484 }
485
486 static inline void
487 sclp_eval_cpmsu(struct gds_vector *start, struct gds_vector *end)
488 {
489         struct gds_vector *vec;
490
491         vec = start;
492         while (vec < end) {
493                 vec = find_gds_vector(vec, end, GDS_ID_TEXTCMD);
494                 if (!vec)
495                         break;
496                 sclp_eval_textcmd((struct gds_subvector *)(vec + 1),
497                                   (void *) vec + vec->length);
498                 vec = (void *) vec + vec->length;
499         }
500 }
501
502
503 static inline void
504 sclp_eval_mdsmu(struct gds_vector *start, void *end)
505 {
506         struct gds_vector *vec;
507
508         vec = find_gds_vector(start, end, GDS_ID_CPMSU);
509         if (vec)
510                 sclp_eval_cpmsu(vec + 1, (void *) vec + vec->length);
511 }
512
513 static void
514 sclp_tty_receiver(struct evbuf_header *evbuf)
515 {
516         struct gds_vector *start, *end, *vec;
517
518         start = (struct gds_vector *)(evbuf + 1);
519         end = (void *) evbuf + evbuf->length;
520         vec = find_gds_vector(start, end, GDS_ID_MDSMU);
521         if (vec)
522                 sclp_eval_mdsmu(vec + 1, (void *) vec + vec->length);
523 }
524
525 static void
526 sclp_tty_state_change(struct sclp_register *reg)
527 {
528 }
529
530 static struct sclp_register sclp_input_event =
531 {
532         .receive_mask = EVTYP_OPCMD_MASK | EVTYP_PMSGCMD_MASK,
533         .state_change_fn = sclp_tty_state_change,
534         .receiver_fn = sclp_tty_receiver
535 };
536
537 static const struct tty_operations sclp_ops = {
538         .open = sclp_tty_open,
539         .close = sclp_tty_close,
540         .write = sclp_tty_write,
541         .put_char = sclp_tty_put_char,
542         .flush_chars = sclp_tty_flush_chars,
543         .write_room = sclp_tty_write_room,
544         .chars_in_buffer = sclp_tty_chars_in_buffer,
545         .flush_buffer = sclp_tty_flush_buffer,
546 };
547
548 static int __init
549 sclp_tty_init(void)
550 {
551         struct tty_driver *driver;
552         void *page;
553         int i;
554         int rc;
555
556         if (!CONSOLE_IS_SCLP)
557                 return 0;
558         driver = alloc_tty_driver(1);
559         if (!driver)
560                 return -ENOMEM;
561
562         rc = sclp_rw_init();
563         if (rc) {
564                 put_tty_driver(driver);
565                 return rc;
566         }
567         /* Allocate pages for output buffering */
568         INIT_LIST_HEAD(&sclp_tty_pages);
569         for (i = 0; i < MAX_KMEM_PAGES; i++) {
570                 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
571                 if (page == NULL) {
572                         put_tty_driver(driver);
573                         return -ENOMEM;
574                 }
575                 list_add_tail((struct list_head *) page, &sclp_tty_pages);
576         }
577         INIT_LIST_HEAD(&sclp_tty_outqueue);
578         spin_lock_init(&sclp_tty_lock);
579         init_timer(&sclp_tty_timer);
580         sclp_ttybuf = NULL;
581         sclp_tty_buffer_count = 0;
582         if (MACHINE_IS_VM) {
583                 /*
584                  * save 4 characters for the CPU number
585                  * written at start of each line by VM/CP
586                  */
587                 sclp_tty_columns = 76;
588                 /* case input lines to lowercase */
589                 sclp_tty_tolower = 1;
590         }
591         sclp_tty_chars_count = 0;
592         sclp_tty = NULL;
593
594         rc = sclp_register(&sclp_input_event);
595         if (rc) {
596                 put_tty_driver(driver);
597                 return rc;
598         }
599
600         driver->owner = THIS_MODULE;
601         driver->driver_name = "sclp_line";
602         driver->name = "sclp_line";
603         driver->major = TTY_MAJOR;
604         driver->minor_start = 64;
605         driver->type = TTY_DRIVER_TYPE_SYSTEM;
606         driver->subtype = SYSTEM_TYPE_TTY;
607         driver->init_termios = tty_std_termios;
608         driver->init_termios.c_iflag = IGNBRK | IGNPAR;
609         driver->init_termios.c_oflag = ONLCR | XTABS;
610         driver->init_termios.c_lflag = ISIG | ECHO;
611         driver->flags = TTY_DRIVER_REAL_RAW;
612         tty_set_operations(driver, &sclp_ops);
613         rc = tty_register_driver(driver);
614         if (rc) {
615                 put_tty_driver(driver);
616                 return rc;
617         }
618         sclp_tty_driver = driver;
619         return 0;
620 }
621 module_init(sclp_tty_init);