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