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);