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/wait.h>
  17 #include <linux/slab.h>
  18 #include <linux/err.h>
  19 #include <linux/init.h>
  20 #include <linux/interrupt.h>
  21 #include <asm/uaccess.h>
  22
  23 #include "ctrlchar.h"
  24 #include "sclp.h"
  25 #include "sclp_rw.h"
  26 #include "sclp_tty.h"
  27
  28 /*
  29  * size of a buffer that collects single characters coming in
  30  * via sclp_tty_put_char()
  31  */
  32 #define SCLP_TTY_BUF_SIZE 512
  33
  34 /*
  35  * There is exactly one SCLP terminal, so we can keep things simple
  36  * and allocate all variables statically.
  37  */
  38
  39 /* Lock to guard over changes to global variables. */
  40 static spinlock_t sclp_tty_lock;
  41 /* List of free pages that can be used for console output buffering. */
  42 static struct list_head sclp_tty_pages;
  43 /* List of full struct sclp_buffer structures ready for output. */
  44 static struct list_head sclp_tty_outqueue;
  45 /* Counter how many buffers are emitted. */
  46 static int sclp_tty_buffer_count;
  47 /* Pointer to current console buffer. */
  48 static struct sclp_buffer *sclp_ttybuf;
  49 /* Timer for delayed output of console messages. */
  50 static struct timer_list sclp_tty_timer;
  51 /* Waitqueue to wait for buffers to get empty. */
  52 static wait_queue_head_t sclp_tty_waitq;
  53
  54 static struct tty_struct *sclp_tty;
  55 static unsigned char sclp_tty_chars[SCLP_TTY_BUF_SIZE];
  56 static unsigned short int sclp_tty_chars_count;
  57
  58 struct tty_driver *sclp_tty_driver;
  59
  60 static int sclp_tty_tolower;
  61 static int sclp_tty_columns = 80;
  62
  63 #define SPACES_PER_TAB 8
  64 #define CASE_DELIMITER 0x6c /* to separate upper and lower case (% in EBCDIC) */
  65
  66 /* This routine is called whenever we try to open a SCLP terminal. */
  67 static int
  68 sclp_tty_open(struct tty_struct *tty, struct file *filp)
  69 {
  70         sclp_tty = tty;
  71         tty->driver_data = NULL;
  72         tty->low_latency = 0;
  73         return 0;
  74 }
  75
  76 /* This routine is called when the SCLP terminal is closed. */
  77 static void
  78 sclp_tty_close(struct tty_struct *tty, struct file *filp)
  79 {
  80         if (tty->count > 1)
  81                 return;
  82         sclp_tty = NULL;
  83 }
  84
  85 /*
  86  * This routine returns the numbers of characters the tty driver
  87  * will accept for queuing to be written.  This number is subject
  88  * to change as output buffers get emptied, or if the output flow
  89  * control is acted. This is not an exact number because not every
  90  * character needs the same space in the sccb. The worst case is
  91  * a string of newlines. Every newlines creates a new mto which
  92  * needs 8 bytes.
  93  */
  94 static int
  95 sclp_tty_write_room (struct tty_struct *tty)
  96 {
  97         unsigned long flags;
  98         struct list_head *l;
  99         int count;
 100
 101         spin_lock_irqsave(&sclp_tty_lock, flags);
 102         count = 0;
 103         if (sclp_ttybuf != NULL)
 104                 count = sclp_buffer_space(sclp_ttybuf) / sizeof(struct mto);
 105         list_for_each(l, &sclp_tty_pages)
 106                 count += NR_EMPTY_MTO_PER_SCCB;
 107         spin_unlock_irqrestore(&sclp_tty_lock, flags);
 108         return count;
 109 }
 110
 111 static void
 112 sclp_ttybuf_callback(struct sclp_buffer *buffer, int rc)
 113 {
 114         unsigned long flags;
 115         void *page;
 116
 117         do {
 118                 page = sclp_unmake_buffer(buffer);
 119                 spin_lock_irqsave(&sclp_tty_lock, flags);
 120                 /* Remove buffer from outqueue */
 121                 list_del(&buffer->list);
 122                 sclp_tty_buffer_count--;
 123                 list_add_tail((struct list_head *) page, &sclp_tty_pages);
 124                 /* Check if there is a pending buffer on the out queue. */
 125                 buffer = NULL;
 126                 if (!list_empty(&sclp_tty_outqueue))
 127                         buffer = list_entry(sclp_tty_outqueue.next,
 128                                             struct sclp_buffer, list);
 129                 spin_unlock_irqrestore(&sclp_tty_lock, flags);
 130         } while (buffer && sclp_emit_buffer(buffer, sclp_ttybuf_callback));
 131         wake_up(&sclp_tty_waitq);
 132         /* check if the tty needs a wake up call */
 133         if (sclp_tty != NULL) {
 134                 tty_wakeup(sclp_tty);
 135         }
 136 }
 137
 138 static inline void
 139 __sclp_ttybuf_emit(struct sclp_buffer *buffer)
 140 {
 141         unsigned long flags;
 142         int count;
 143         int rc;
 144
 145         spin_lock_irqsave(&sclp_tty_lock, flags);
 146         list_add_tail(&buffer->list, &sclp_tty_outqueue);
 147         count = sclp_tty_buffer_count++;
 148         spin_unlock_irqrestore(&sclp_tty_lock, flags);
 149         if (count)
 150                 return;
 151         rc = sclp_emit_buffer(buffer, sclp_ttybuf_callback);
 152         if (rc)
 153                 sclp_ttybuf_callback(buffer, rc);
 154 }
 155
 156 /*
 157  * When this routine is called from the timer then we flush the
 158  * temporary write buffer.
 159  */
 160 static void
 161 sclp_tty_timeout(unsigned long data)
 162 {
 163         unsigned long flags;
 164         struct sclp_buffer *buf;
 165
 166         spin_lock_irqsave(&sclp_tty_lock, flags);
 167         buf = sclp_ttybuf;
 168         sclp_ttybuf = NULL;
 169         spin_unlock_irqrestore(&sclp_tty_lock, flags);
 170
 171         if (buf != NULL) {
 172                 __sclp_ttybuf_emit(buf);
 173         }
 174 }
 175
 176 /*
 177  * Write a string to the sclp tty.
 178  */
 179 static void
 180 sclp_tty_write_string(const unsigned char *str, int count)
 181 {
 182         unsigned long flags;
 183         void *page;
 184         int written;
 185         struct sclp_buffer *buf;
 186
 187         if (count <= 0)
 188                 return;
 189         spin_lock_irqsave(&sclp_tty_lock, flags);
 190         do {
 191                 /* Create a sclp output buffer if none exists yet */
 192                 if (sclp_ttybuf == NULL) {
 193                         while (list_empty(&sclp_tty_pages)) {
 194                                 spin_unlock_irqrestore(&sclp_tty_lock, flags);
 195                                 if (in_interrupt())
 196                                         sclp_sync_wait();
 197                                 else
 198                                         wait_event(sclp_tty_waitq,
 199                                                 !list_empty(&sclp_tty_pages));
 200                                 spin_lock_irqsave(&sclp_tty_lock, flags);
 201                         }
 202                         page = sclp_tty_pages.next;
 203                         list_del((struct list_head *) page);
 204                         sclp_ttybuf = sclp_make_buffer(page, sclp_tty_columns,
 205                                                        SPACES_PER_TAB);
 206                 }
 207                 /* try to write the string to the current output buffer */
 208                 written = sclp_write(sclp_ttybuf, str, count);
 209                 if (written == count)
 210                         break;
 211                 /*
 212                  * Not all characters could be written to the current
 213                  * output buffer. Emit the buffer, create a new buffer
 214                  * and then output the rest of the string.
 215                  */
 216                 buf = sclp_ttybuf;
 217                 sclp_ttybuf = NULL;
 218                 spin_unlock_irqrestore(&sclp_tty_lock, flags);
 219                 __sclp_ttybuf_emit(buf);
 220                 spin_lock_irqsave(&sclp_tty_lock, flags);
 221                 str += written;
 222                 count -= written;
 223         } while (count > 0);
 224         /* Setup timer to output current console buffer after 1/10 second */
 225         if (sclp_ttybuf && sclp_chars_in_buffer(sclp_ttybuf) &&
 226             !timer_pending(&sclp_tty_timer)) {
 227                 init_timer(&sclp_tty_timer);
 228                 sclp_tty_timer.function = sclp_tty_timeout;
 229                 sclp_tty_timer.data = 0UL;
 230                 sclp_tty_timer.expires = jiffies + HZ/10;
 231                 add_timer(&sclp_tty_timer);
 232         }
 233         spin_unlock_irqrestore(&sclp_tty_lock, flags);
 234 }
 235
 236 /*
 237  * This routine is called by the kernel to write a series of characters to the
 238  * tty device. The characters may come from user space or kernel space. This
 239  * routine will return the number of characters actually accepted for writing.
 240  */
 241 static int
 242 sclp_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
 243 {
 244         if (sclp_tty_chars_count > 0) {
 245                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
 246                 sclp_tty_chars_count = 0;
 247         }
 248         sclp_tty_write_string(buf, count);
 249         return count;
 250 }
 251
 252 /*
 253  * This routine is called by the kernel to write a single character to the tty
 254  * device. If the kernel uses this routine, it must call the flush_chars()
 255  * routine (if defined) when it is done stuffing characters into the driver.
 256  *
 257  * Characters provided to sclp_tty_put_char() are buffered by the SCLP driver.
 258  * If the given character is a '\n' the contents of the SCLP write buffer
 259  * - including previous characters from sclp_tty_put_char() and strings from
 260  * sclp_write() without final '\n' - will be written.
 261  */
 262 static int
 263 sclp_tty_put_char(struct tty_struct *tty, unsigned char ch)
 264 {
 265         sclp_tty_chars[sclp_tty_chars_count++] = ch;
 266         if (ch == '\n' || sclp_tty_chars_count >= SCLP_TTY_BUF_SIZE) {
 267                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
 268                 sclp_tty_chars_count = 0;
 269         } return 1;
 270 }
 271
 272 /*
 273  * This routine is called by the kernel after it has written a series of
 274  * characters to the tty device using put_char().
 275  */
 276 static void
 277 sclp_tty_flush_chars(struct tty_struct *tty)
 278 {
 279         if (sclp_tty_chars_count > 0) {
 280                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
 281                 sclp_tty_chars_count = 0;
 282         }
 283 }
 284
 285 /*
 286  * This routine returns the number of characters in the write buffer of the
 287  * SCLP driver. The provided number includes all characters that are stored
 288  * in the SCCB (will be written next time the SCLP is not busy) as well as
 289  * characters in the write buffer (will not be written as long as there is a
 290  * final line feed missing).
 291  */
 292 static int
 293 sclp_tty_chars_in_buffer(struct tty_struct *tty)
 294 {
 295         unsigned long flags;
 296         struct list_head *l;
 297         struct sclp_buffer *t;
 298         int count;
 299
 300         spin_lock_irqsave(&sclp_tty_lock, flags);
 301         count = 0;
 302         if (sclp_ttybuf != NULL)
 303                 count = sclp_chars_in_buffer(sclp_ttybuf);
 304         list_for_each(l, &sclp_tty_outqueue) {
 305                 t = list_entry(l, struct sclp_buffer, list);
 306                 count += sclp_chars_in_buffer(t);
 307         }
 308         spin_unlock_irqrestore(&sclp_tty_lock, flags);
 309         return count;
 310 }
 311
 312 /*
 313  * removes all content from buffers of low level driver
 314  */
 315 static void
 316 sclp_tty_flush_buffer(struct tty_struct *tty)
 317 {
 318         if (sclp_tty_chars_count > 0) {
 319                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count);
 320                 sclp_tty_chars_count = 0;
 321         }
 322 }
 323
 324 /*
 325  * push input to tty
 326  */
 327 static void
 328 sclp_tty_input(unsigned char* buf, unsigned int count)
 329 {
 330         unsigned int cchar;
 331
 332         /*
 333          * If this tty driver is currently closed
 334          * then throw the received input away.
 335          */
 336         if (sclp_tty == NULL)
 337                 return;
 338         cchar = ctrlchar_handle(buf, count, sclp_tty);
 339         switch (cchar & CTRLCHAR_MASK) {
 340         case CTRLCHAR_SYSRQ:
 341                 break;
 342         case CTRLCHAR_CTRL:
 343                 tty_insert_flip_char(sclp_tty, cchar, TTY_NORMAL);
 344                 tty_flip_buffer_push(sclp_tty);
 345                 break;
 346         case CTRLCHAR_NONE:
 347                 /* send (normal) input to line discipline */
 348                 if (count < 2 ||
 349                     (strncmp((const char *) buf + count - 2, "^n", 2) &&
 350                      strncmp((const char *) buf + count - 2, "\252n", 2))) {
 351                         /* add the auto \n */
 352                         tty_insert_flip_string(sclp_tty, buf, count);
 353                         tty_insert_flip_char(sclp_tty, '\n', TTY_NORMAL);
 354                 } else
 355                         tty_insert_flip_string(sclp_tty, buf, count - 2);
 356                 tty_flip_buffer_push(sclp_tty);
 357                 break;
 358         }
 359 }
 360
 361 /*
 362  * get a EBCDIC string in upper/lower case,
 363  * find out characters in lower/upper case separated by a special character,
 364  * modifiy original string,
 365  * returns length of resulting string
 366  */
 367 static int sclp_switch_cases(unsigned char *buf, int count)
 368 {
 369         unsigned char *ip, *op;
 370         int toggle;
 371
 372         /* initially changing case is off */
 373         toggle = 0;
 374         ip = op = buf;
 375         while (count-- > 0) {
 376                 /* compare with special character */
 377                 if (*ip == CASE_DELIMITER) {
 378                         /* followed by another special character? */
 379                         if (count && ip[1] == CASE_DELIMITER) {
 380                                 /*
 381                                  * ... then put a single copy of the special
 382                                  * character to the output string
 383                                  */
 384                                 *op++ = *ip++;
 385                                 count--;
 386                         } else
 387                                 /*
 388                                  * ... special character follower by a normal
 389                                  * character toggles the case change behaviour
 390                                  */
 391                                 toggle = ~toggle;
 392                         /* skip special character */
 393                         ip++;
 394                 } else
 395                         /* not the special character */
 396                         if (toggle)
 397                                 /* but case switching is on */
 398                                 if (sclp_tty_tolower)
 399                                         /* switch to uppercase */
 400                                         *op++ = _ebc_toupper[(int) *ip++];
 401                                 else
 402                                         /* switch to lowercase */
 403                                         *op++ = _ebc_tolower[(int) *ip++];
 404                         else
 405                                 /* no case switching, copy the character */
 406                                 *op++ = *ip++;
 407         }
 408         /* return length of reformatted string. */
 409         return op - buf;
 410 }
 411
 412 static void
 413 sclp_get_input(unsigned char *start, unsigned char *end)
 414 {
 415         int count;
 416
 417         count = end - start;
 418         if (sclp_tty_tolower)
 419                 EBC_TOLOWER(start, count);
 420         count = sclp_switch_cases(start, count);
 421         /* convert EBCDIC to ASCII (modify original input in SCCB) */
 422         sclp_ebcasc_str(start, count);
 423
 424         /* transfer input to high level driver */
 425         sclp_tty_input(start, count);
 426 }
 427
 428 static inline struct gds_vector *
 429 find_gds_vector(struct gds_vector *start, struct gds_vector *end, u16 id)
 430 {
 431         struct gds_vector *vec;
 432
 433         for (vec = start; vec < end; vec = (void *) vec + vec->length)
 434                 if (vec->gds_id == id)
 435                         return vec;
 436         return NULL;
 437 }
 438
 439 static inline struct gds_subvector *
 440 find_gds_subvector(struct gds_subvector *start,
 441                    struct gds_subvector *end, u8 key)
 442 {
 443         struct gds_subvector *subvec;
 444
 445         for (subvec = start; subvec < end;
 446              subvec = (void *) subvec + subvec->length)
 447                 if (subvec->key == key)
 448                         return subvec;
 449         return NULL;
 450 }
 451
 452 static inline void
 453 sclp_eval_selfdeftextmsg(struct gds_subvector *start,
 454                          struct gds_subvector *end)
 455 {
 456         struct gds_subvector *subvec;
 457
 458         subvec = start;
 459         while (subvec < end) {
 460                 subvec = find_gds_subvector(subvec, end, 0x30);
 461                 if (!subvec)
 462                         break;
 463                 sclp_get_input((unsigned char *)(subvec + 1),
 464                                (unsigned char *) subvec + subvec->length);
 465                 subvec = (void *) subvec + subvec->length;
 466         }
 467 }
 468
 469 static inline void
 470 sclp_eval_textcmd(struct gds_subvector *start,
 471                   struct gds_subvector *end)
 472 {
 473         struct gds_subvector *subvec;
 474
 475         subvec = start;
 476         while (subvec < end) {
 477                 subvec = find_gds_subvector(subvec, end,
 478                                             GDS_KEY_SELFDEFTEXTMSG);
 479                 if (!subvec)
 480                         break;
 481                 sclp_eval_selfdeftextmsg((struct gds_subvector *)(subvec + 1),
 482                                          (void *)subvec + subvec->length);
 483                 subvec = (void *) subvec + subvec->length;
 484         }
 485 }
 486
 487 static inline void
 488 sclp_eval_cpmsu(struct gds_vector *start, struct gds_vector *end)
 489 {
 490         struct gds_vector *vec;
 491
 492         vec = start;
 493         while (vec < end) {
 494                 vec = find_gds_vector(vec, end, GDS_ID_TEXTCMD);
 495                 if (!vec)
 496                         break;
 497                 sclp_eval_textcmd((struct gds_subvector *)(vec + 1),
 498                                   (void *) vec + vec->length);
 499                 vec = (void *) vec + vec->length;
 500         }
 501 }
 502
 503
 504 static inline void
 505 sclp_eval_mdsmu(struct gds_vector *start, void *end)
 506 {
 507         struct gds_vector *vec;
 508
 509         vec = find_gds_vector(start, end, GDS_ID_CPMSU);
 510         if (vec)
 511                 sclp_eval_cpmsu(vec + 1, (void *) vec + vec->length);
 512 }
 513
 514 static void
 515 sclp_tty_receiver(struct evbuf_header *evbuf)
 516 {
 517         struct gds_vector *start, *end, *vec;
 518
 519         start = (struct gds_vector *)(evbuf + 1);
 520         end = (void *) evbuf + evbuf->length;
 521         vec = find_gds_vector(start, end, GDS_ID_MDSMU);
 522         if (vec)
 523                 sclp_eval_mdsmu(vec + 1, (void *) vec + vec->length);
 524 }
 525
 526 static void
 527 sclp_tty_state_change(struct sclp_register *reg)
 528 {
 529 }
 530
 531 static struct sclp_register sclp_input_event =
 532 {
 533         .receive_mask = EVTYP_OPCMD_MASK | EVTYP_PMSGCMD_MASK,
 534         .state_change_fn = sclp_tty_state_change,
 535         .receiver_fn = sclp_tty_receiver
 536 };
 537
 538 static const struct tty_operations sclp_ops = {
 539         .open = sclp_tty_open,
 540         .close = sclp_tty_close,
 541         .write = sclp_tty_write,
 542         .put_char = sclp_tty_put_char,
 543         .flush_chars = sclp_tty_flush_chars,
 544         .write_room = sclp_tty_write_room,
 545         .chars_in_buffer = sclp_tty_chars_in_buffer,
 546         .flush_buffer = sclp_tty_flush_buffer,
 547 };
 548
 549 static int __init
 550 sclp_tty_init(void)
 551 {
 552         struct tty_driver *driver;
 553         void *page;
 554         int i;
 555         int rc;
 556
 557         if (!CONSOLE_IS_SCLP)
 558                 return 0;
 559         driver = alloc_tty_driver(1);
 560         if (!driver)
 561                 return -ENOMEM;
 562
 563         rc = sclp_rw_init();
 564         if (rc) {
 565                 put_tty_driver(driver);
 566                 return rc;
 567         }
 568         /* Allocate pages for output buffering */
 569         INIT_LIST_HEAD(&sclp_tty_pages);
 570         for (i = 0; i < MAX_KMEM_PAGES; i++) {
 571                 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 572                 if (page == NULL) {
 573                         put_tty_driver(driver);
 574                         return -ENOMEM;
 575                 }
 576                 list_add_tail((struct list_head *) page, &sclp_tty_pages);
 577         }
 578         INIT_LIST_HEAD(&sclp_tty_outqueue);
 579         spin_lock_init(&sclp_tty_lock);
 580         init_waitqueue_head(&sclp_tty_waitq);
 581         init_timer(&sclp_tty_timer);
 582         sclp_ttybuf = NULL;
 583         sclp_tty_buffer_count = 0;
 584         if (MACHINE_IS_VM) {
 585                 /*
 586                  * save 4 characters for the CPU number
 587                  * written at start of each line by VM/CP
 588                  */
 589                 sclp_tty_columns = 76;
 590                 /* case input lines to lowercase */
 591                 sclp_tty_tolower = 1;
 592         }
 593         sclp_tty_chars_count = 0;
 594         sclp_tty = NULL;
 595
 596         rc = sclp_register(&sclp_input_event);
 597         if (rc) {
 598                 put_tty_driver(driver);
 599                 return rc;
 600         }
 601
 602         driver->owner = THIS_MODULE;
 603         driver->driver_name = "sclp_line";
 604         driver->name = "sclp_line";
 605         driver->major = TTY_MAJOR;
 606         driver->minor_start = 64;
 607         driver->type = TTY_DRIVER_TYPE_SYSTEM;
 608         driver->subtype = SYSTEM_TYPE_TTY;
 609         driver->init_termios = tty_std_termios;
 610         driver->init_termios.c_iflag = IGNBRK | IGNPAR;
 611         driver->init_termios.c_oflag = ONLCR | XTABS;
 612         driver->init_termios.c_lflag = ISIG | ECHO;
 613         driver->flags = TTY_DRIVER_REAL_RAW;
 614         tty_set_operations(driver, &sclp_ops);
 615         rc = tty_register_driver(driver);
 616         if (rc) {
 617                 put_tty_driver(driver);
 618                 return rc;
 619         }
 620         sclp_tty_driver = driver;
 621         return 0;
 622 }
 623 module_init(sclp_tty_init);