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