drivers/s390/char/sclp_tty.c

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