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/err.h>
  17 #include <linux/init.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/gfp.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_port sclp_port;
  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         tty_port_tty_set(&sclp_port, 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         tty_port_tty_set(&sclp_port, 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         struct tty_struct *tty;
 112         unsigned long flags;
 113         void *page;
 114
 115         do {
 116                 page = sclp_unmake_buffer(buffer);
 117                 spin_lock_irqsave(&sclp_tty_lock, flags);
 118                 /* Remove buffer from outqueue */
 119                 list_del(&buffer->list);
 120                 sclp_tty_buffer_count--;
 121                 list_add_tail((struct list_head *) page, &sclp_tty_pages);
 122                 /* Check if there is a pending buffer on the out queue. */
 123                 buffer = NULL;
 124                 if (!list_empty(&sclp_tty_outqueue))
 125                         buffer = list_entry(sclp_tty_outqueue.next,
 126                                             struct sclp_buffer, list);
 127                 spin_unlock_irqrestore(&sclp_tty_lock, flags);
 128         } while (buffer && sclp_emit_buffer(buffer, sclp_ttybuf_callback));
 129         /* check if the tty needs a wake up call */
 130         tty = tty_port_tty_get(&sclp_port);
 131         if (tty != NULL) {
 132                 tty_wakeup(tty);
 133                 tty_kref_put(tty);
 134         }
 135 }
 136
 137 static inline void
 138 __sclp_ttybuf_emit(struct sclp_buffer *buffer)
 139 {
 140         unsigned long flags;
 141         int count;
 142         int rc;
 143
 144         spin_lock_irqsave(&sclp_tty_lock, flags);
 145         list_add_tail(&buffer->list, &sclp_tty_outqueue);
 146         count = sclp_tty_buffer_count++;
 147         spin_unlock_irqrestore(&sclp_tty_lock, flags);
 148         if (count)
 149                 return;
 150         rc = sclp_emit_buffer(buffer, sclp_ttybuf_callback);
 151         if (rc)
 152                 sclp_ttybuf_callback(buffer, rc);
 153 }
 154
 155 /*
 156  * When this routine is called from the timer then we flush the
 157  * temporary write buffer.
 158  */
 159 static void
 160 sclp_tty_timeout(unsigned long data)
 161 {
 162         unsigned long flags;
 163         struct sclp_buffer *buf;
 164
 165         spin_lock_irqsave(&sclp_tty_lock, flags);
 166         buf = sclp_ttybuf;
 167         sclp_ttybuf = NULL;
 168         spin_unlock_irqrestore(&sclp_tty_lock, flags);
 169
 170         if (buf != NULL) {
 171                 __sclp_ttybuf_emit(buf);
 172         }
 173 }
 174
 175 /*
 176  * Write a string to the sclp tty.
 177  */
 178 static int sclp_tty_write_string(const unsigned char *str, int count, int may_fail)
 179 {
 180         unsigned long flags;
 181         void *page;
 182         int written;
 183         int overall_written;
 184         struct sclp_buffer *buf;
 185
 186         if (count <= 0)
 187                 return 0;
 188         overall_written = 0;
 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 (may_fail)
 196                                         goto out;
 197                                 else
 198                                         sclp_sync_wait();
 199                                 spin_lock_irqsave(&sclp_tty_lock, flags);
 200                         }
 201                         page = sclp_tty_pages.next;
 202                         list_del((struct list_head *) page);
 203                         sclp_ttybuf = sclp_make_buffer(page, sclp_tty_columns,
 204                                                        SPACES_PER_TAB);
 205                 }
 206                 /* try to write the string to the current output buffer */
 207                 written = sclp_write(sclp_ttybuf, str, count);
 208                 overall_written += written;
 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 out:
 235         return overall_written;
 236 }
 237
 238 /*
 239  * This routine is called by the kernel to write a series of characters to the
 240  * tty device. The characters may come from user space or kernel space. This
 241  * routine will return the number of characters actually accepted for writing.
 242  */
 243 static int
 244 sclp_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
 245 {
 246         if (sclp_tty_chars_count > 0) {
 247                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);
 248                 sclp_tty_chars_count = 0;
 249         }
 250         return sclp_tty_write_string(buf, count, 1);
 251 }
 252
 253 /*
 254  * This routine is called by the kernel to write a single character to the tty
 255  * device. If the kernel uses this routine, it must call the flush_chars()
 256  * routine (if defined) when it is done stuffing characters into the driver.
 257  *
 258  * Characters provided to sclp_tty_put_char() are buffered by the SCLP driver.
 259  * If the given character is a '\n' the contents of the SCLP write buffer
 260  * - including previous characters from sclp_tty_put_char() and strings from
 261  * sclp_write() without final '\n' - will be written.
 262  */
 263 static int
 264 sclp_tty_put_char(struct tty_struct *tty, unsigned char ch)
 265 {
 266         sclp_tty_chars[sclp_tty_chars_count++] = ch;
 267         if (ch == '\n' || sclp_tty_chars_count >= SCLP_TTY_BUF_SIZE) {
 268                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);
 269                 sclp_tty_chars_count = 0;
 270         }
 271         return 1;
 272 }
 273
 274 /*
 275  * This routine is called by the kernel after it has written a series of
 276  * characters to the tty device using put_char().
 277  */
 278 static void
 279 sclp_tty_flush_chars(struct tty_struct *tty)
 280 {
 281         if (sclp_tty_chars_count > 0) {
 282                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);
 283                 sclp_tty_chars_count = 0;
 284         }
 285 }
 286
 287 /*
 288  * This routine returns the number of characters in the write buffer of the
 289  * SCLP driver. The provided number includes all characters that are stored
 290  * in the SCCB (will be written next time the SCLP is not busy) as well as
 291  * characters in the write buffer (will not be written as long as there is a
 292  * final line feed missing).
 293  */
 294 static int
 295 sclp_tty_chars_in_buffer(struct tty_struct *tty)
 296 {
 297         unsigned long flags;
 298         struct list_head *l;
 299         struct sclp_buffer *t;
 300         int count;
 301
 302         spin_lock_irqsave(&sclp_tty_lock, flags);
 303         count = 0;
 304         if (sclp_ttybuf != NULL)
 305                 count = sclp_chars_in_buffer(sclp_ttybuf);
 306         list_for_each(l, &sclp_tty_outqueue) {
 307                 t = list_entry(l, struct sclp_buffer, list);
 308                 count += sclp_chars_in_buffer(t);
 309         }
 310         spin_unlock_irqrestore(&sclp_tty_lock, flags);
 311         return count;
 312 }
 313
 314 /*
 315  * removes all content from buffers of low level driver
 316  */
 317 static void
 318 sclp_tty_flush_buffer(struct tty_struct *tty)
 319 {
 320         if (sclp_tty_chars_count > 0) {
 321                 sclp_tty_write_string(sclp_tty_chars, sclp_tty_chars_count, 0);
 322                 sclp_tty_chars_count = 0;
 323         }
 324 }
 325
 326 /*
 327  * push input to tty
 328  */
 329 static void
 330 sclp_tty_input(unsigned char* buf, unsigned int count)
 331 {
 332         struct tty_struct *tty = tty_port_tty_get(&sclp_port);
 333         unsigned int cchar;
 334
 335         /*
 336          * If this tty driver is currently closed
 337          * then throw the received input away.
 338          */
 339         if (tty == NULL)
 340                 return;
 341         cchar = ctrlchar_handle(buf, count, tty);
 342         switch (cchar & CTRLCHAR_MASK) {
 343         case CTRLCHAR_SYSRQ:
 344                 break;
 345         case CTRLCHAR_CTRL:
 346                 tty_insert_flip_char(tty, cchar, TTY_NORMAL);
 347                 tty_flip_buffer_push(tty);
 348                 break;
 349         case CTRLCHAR_NONE:
 350                 /* send (normal) input to line discipline */
 351                 if (count < 2 ||
 352                     (strncmp((const char *) buf + count - 2, "^n", 2) &&
 353                      strncmp((const char *) buf + count - 2, "\252n", 2))) {
 354                         /* add the auto \n */
 355                         tty_insert_flip_string(tty, buf, count);
 356                         tty_insert_flip_char(tty, '\n', TTY_NORMAL);
 357                 } else
 358                         tty_insert_flip_string(tty, buf, count - 2);
 359                 tty_flip_buffer_push(tty);
 360                 break;
 361         }
 362         tty_kref_put(tty);
 363 }
 364
 365 /*
 366  * get a EBCDIC string in upper/lower case,
 367  * find out characters in lower/upper case separated by a special character,
 368  * modifiy original string,
 369  * returns length of resulting string
 370  */
 371 static int sclp_switch_cases(unsigned char *buf, int count)
 372 {
 373         unsigned char *ip, *op;
 374         int toggle;
 375
 376         /* initially changing case is off */
 377         toggle = 0;
 378         ip = op = buf;
 379         while (count-- > 0) {
 380                 /* compare with special character */
 381                 if (*ip == CASE_DELIMITER) {
 382                         /* followed by another special character? */
 383                         if (count && ip[1] == CASE_DELIMITER) {
 384                                 /*
 385                                  * ... then put a single copy of the special
 386                                  * character to the output string
 387                                  */
 388                                 *op++ = *ip++;
 389                                 count--;
 390                         } else
 391                                 /*
 392                                  * ... special character follower by a normal
 393                                  * character toggles the case change behaviour
 394                                  */
 395                                 toggle = ~toggle;
 396                         /* skip special character */
 397                         ip++;
 398                 } else
 399                         /* not the special character */
 400                         if (toggle)
 401                                 /* but case switching is on */
 402                                 if (sclp_tty_tolower)
 403                                         /* switch to uppercase */
 404                                         *op++ = _ebc_toupper[(int) *ip++];
 405                                 else
 406                                         /* switch to lowercase */
 407                                         *op++ = _ebc_tolower[(int) *ip++];
 408                         else
 409                                 /* no case switching, copy the character */
 410                                 *op++ = *ip++;
 411         }
 412         /* return length of reformatted string. */
 413         return op - buf;
 414 }
 415
 416 static void sclp_get_input(struct gds_subvector *sv)
 417 {
 418         unsigned char *str;
 419         int count;
 420
 421         str = (unsigned char *) (sv + 1);
 422         count = sv->length - sizeof(*sv);
 423         if (sclp_tty_tolower)
 424                 EBC_TOLOWER(str, count);
 425         count = sclp_switch_cases(str, count);
 426         /* convert EBCDIC to ASCII (modify original input in SCCB) */
 427         sclp_ebcasc_str(str, count);
 428
 429         /* transfer input to high level driver */
 430         sclp_tty_input(str, count);
 431 }
 432
 433 static inline void sclp_eval_selfdeftextmsg(struct gds_subvector *sv)
 434 {
 435         void *end;
 436
 437         end = (void *) sv + sv->length;
 438         for (sv = sv + 1; (void *) sv < end; sv = (void *) sv + sv->length)
 439                 if (sv->key == 0x30)
 440                         sclp_get_input(sv);
 441 }
 442
 443 static inline void sclp_eval_textcmd(struct gds_vector *v)
 444 {
 445         struct gds_subvector *sv;
 446         void *end;
 447
 448         end = (void *) v + v->length;
 449         for (sv = (struct gds_subvector *) (v + 1);
 450              (void *) sv < end; sv = (void *) sv + sv->length)
 451                 if (sv->key == GDS_KEY_SELFDEFTEXTMSG)
 452                         sclp_eval_selfdeftextmsg(sv);
 453
 454 }
 455
 456 static inline void sclp_eval_cpmsu(struct gds_vector *v)
 457 {
 458         void *end;
 459
 460         end = (void *) v + v->length;
 461         for (v = v + 1; (void *) v < end; v = (void *) v + v->length)
 462                 if (v->gds_id == GDS_ID_TEXTCMD)
 463                         sclp_eval_textcmd(v);
 464 }
 465
 466
 467 static inline void sclp_eval_mdsmu(struct gds_vector *v)
 468 {
 469         v = sclp_find_gds_vector(v + 1, (void *) v + v->length, GDS_ID_CPMSU);
 470         if (v)
 471                 sclp_eval_cpmsu(v);
 472 }
 473
 474 static void sclp_tty_receiver(struct evbuf_header *evbuf)
 475 {
 476         struct gds_vector *v;
 477
 478         v = sclp_find_gds_vector(evbuf + 1, (void *) evbuf + evbuf->length,
 479                                  GDS_ID_MDSMU);
 480         if (v)
 481                 sclp_eval_mdsmu(v);
 482 }
 483
 484 static void
 485 sclp_tty_state_change(struct sclp_register *reg)
 486 {
 487 }
 488
 489 static struct sclp_register sclp_input_event =
 490 {
 491         .receive_mask = EVTYP_OPCMD_MASK | EVTYP_PMSGCMD_MASK,
 492         .state_change_fn = sclp_tty_state_change,
 493         .receiver_fn = sclp_tty_receiver
 494 };
 495
 496 static const struct tty_operations sclp_ops = {
 497         .open = sclp_tty_open,
 498         .close = sclp_tty_close,
 499         .write = sclp_tty_write,
 500         .put_char = sclp_tty_put_char,
 501         .flush_chars = sclp_tty_flush_chars,
 502         .write_room = sclp_tty_write_room,
 503         .chars_in_buffer = sclp_tty_chars_in_buffer,
 504         .flush_buffer = sclp_tty_flush_buffer,
 505 };
 506
 507 static int __init
 508 sclp_tty_init(void)
 509 {
 510         struct tty_driver *driver;
 511         void *page;
 512         int i;
 513         int rc;
 514
 515         if (!CONSOLE_IS_SCLP)
 516                 return 0;
 517         driver = alloc_tty_driver(1);
 518         if (!driver)
 519                 return -ENOMEM;
 520
 521         rc = sclp_rw_init();
 522         if (rc) {
 523                 put_tty_driver(driver);
 524                 return rc;
 525         }
 526         /* Allocate pages for output buffering */
 527         INIT_LIST_HEAD(&sclp_tty_pages);
 528         for (i = 0; i < MAX_KMEM_PAGES; i++) {
 529                 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 530                 if (page == NULL) {
 531                         put_tty_driver(driver);
 532                         return -ENOMEM;
 533                 }
 534                 list_add_tail((struct list_head *) page, &sclp_tty_pages);
 535         }
 536         INIT_LIST_HEAD(&sclp_tty_outqueue);
 537         spin_lock_init(&sclp_tty_lock);
 538         init_timer(&sclp_tty_timer);
 539         sclp_ttybuf = NULL;
 540         sclp_tty_buffer_count = 0;
 541         if (MACHINE_IS_VM) {
 542                 /*
 543                  * save 4 characters for the CPU number
 544                  * written at start of each line by VM/CP
 545                  */
 546                 sclp_tty_columns = 76;
 547                 /* case input lines to lowercase */
 548                 sclp_tty_tolower = 1;
 549         }
 550         sclp_tty_chars_count = 0;
 551         tty_port_init(&sclp_port);
 552
 553         rc = sclp_register(&sclp_input_event);
 554         if (rc) {
 555                 put_tty_driver(driver);
 556                 return rc;
 557         }
 558
 559         driver->driver_name = "sclp_line";
 560         driver->name = "sclp_line";
 561         driver->major = TTY_MAJOR;
 562         driver->minor_start = 64;
 563         driver->type = TTY_DRIVER_TYPE_SYSTEM;
 564         driver->subtype = SYSTEM_TYPE_TTY;
 565         driver->init_termios = tty_std_termios;
 566         driver->init_termios.c_iflag = IGNBRK | IGNPAR;
 567         driver->init_termios.c_oflag = ONLCR | XTABS;
 568         driver->init_termios.c_lflag = ISIG | ECHO;
 569         driver->flags = TTY_DRIVER_REAL_RAW;
 570         tty_set_operations(driver, &sclp_ops);
 571         rc = tty_register_driver(driver);
 572         if (rc) {
 573                 put_tty_driver(driver);
 574                 return rc;
 575         }
 576         sclp_tty_driver = driver;
 577         return 0;
 578 }
 579 module_init(sclp_tty_init);