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   1 /*
   2  *  drivers/s390/char/sclp_vt220.c
   3  *    SCLP VT220 terminal driver.
   4  *
   5  *  S390 version
   6  *    Copyright IBM Corp. 2003,2008
   7  *    Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/list.h>
  13 #include <linux/wait.h>
  14 #include <linux/timer.h>
  15 #include <linux/kernel.h>
  16 #include <linux/tty.h>
  17 #include <linux/tty_driver.h>
  18 #include <linux/tty_flip.h>
  19 #include <linux/errno.h>
  20 #include <linux/mm.h>
  21 #include <linux/major.h>
  22 #include <linux/console.h>
  23 #include <linux/kdev_t.h>
  24 #include <linux/bootmem.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/init.h>
  27 #include <linux/reboot.h>
  28
  29 #include <asm/uaccess.h>
  30 #include "sclp.h"
  31
  32 #define SCLP_VT220_MAJOR                TTY_MAJOR
  33 #define SCLP_VT220_MINOR                65
  34 #define SCLP_VT220_DRIVER_NAME          "sclp_vt220"
  35 #define SCLP_VT220_DEVICE_NAME          "ttysclp"
  36 #define SCLP_VT220_CONSOLE_NAME         "ttyS"
  37 #define SCLP_VT220_CONSOLE_INDEX        1       /* console=ttyS1 */
  38 #define SCLP_VT220_BUF_SIZE             80
  39
  40 /* Representation of a single write request */
  41 struct sclp_vt220_request {
  42         struct list_head list;
  43         struct sclp_req sclp_req;
  44         int retry_count;
  45 };
  46
  47 /* VT220 SCCB */
  48 struct sclp_vt220_sccb {
  49         struct sccb_header header;
  50         struct evbuf_header evbuf;
  51 };
  52
  53 #define SCLP_VT220_MAX_CHARS_PER_BUFFER (PAGE_SIZE - \
  54                                          sizeof(struct sclp_vt220_request) - \
  55                                          sizeof(struct sclp_vt220_sccb))
  56
  57 /* Structures and data needed to register tty driver */
  58 static struct tty_driver *sclp_vt220_driver;
  59
  60 /* The tty_struct that the kernel associated with us */
  61 static struct tty_struct *sclp_vt220_tty;
  62
  63 /* Lock to protect internal data from concurrent access */
  64 static spinlock_t sclp_vt220_lock;
  65
  66 /* List of empty pages to be used as write request buffers */
  67 static struct list_head sclp_vt220_empty;
  68
  69 /* List of pending requests */
  70 static struct list_head sclp_vt220_outqueue;
  71
  72 /* Number of requests in outqueue */
  73 static int sclp_vt220_outqueue_count;
  74
  75 /* Timer used for delaying write requests to merge subsequent messages into
  76  * a single buffer */
  77 static struct timer_list sclp_vt220_timer;
  78
  79 /* Pointer to current request buffer which has been partially filled but not
  80  * yet sent */
  81 static struct sclp_vt220_request *sclp_vt220_current_request;
  82
  83 /* Number of characters in current request buffer */
  84 static int sclp_vt220_buffered_chars;
  85
  86 /* Counter controlling core driver initialization. */
  87 static int __initdata sclp_vt220_init_count;
  88
  89 /* Flag indicating that sclp_vt220_current_request should really
  90  * have been already queued but wasn't because the SCLP was processing
  91  * another buffer */
  92 static int sclp_vt220_flush_later;
  93
  94 static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
  95 static int __sclp_vt220_emit(struct sclp_vt220_request *request);
  96 static void sclp_vt220_emit_current(void);
  97
  98 /* Registration structure for our interest in SCLP event buffers */
  99 static struct sclp_register sclp_vt220_register = {
 100         .send_mask              = EVTYP_VT220MSG_MASK,
 101         .receive_mask           = EVTYP_VT220MSG_MASK,
 102         .state_change_fn        = NULL,
 103         .receiver_fn            = sclp_vt220_receiver_fn
 104 };
 105
 106
 107 /*
 108  * Put provided request buffer back into queue and check emit pending
 109  * buffers if necessary.
 110  */
 111 static void
 112 sclp_vt220_process_queue(struct sclp_vt220_request *request)
 113 {
 114         unsigned long flags;
 115         void *page;
 116
 117         do {
 118                 /* Put buffer back to list of empty buffers */
 119                 page = request->sclp_req.sccb;
 120                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 121                 /* Move request from outqueue to empty queue */
 122                 list_del(&request->list);
 123                 sclp_vt220_outqueue_count--;
 124                 list_add_tail((struct list_head *) page, &sclp_vt220_empty);
 125                 /* Check if there is a pending buffer on the out queue. */
 126                 request = NULL;
 127                 if (!list_empty(&sclp_vt220_outqueue))
 128                         request = list_entry(sclp_vt220_outqueue.next,
 129                                              struct sclp_vt220_request, list);
 130                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 131         } while (request && __sclp_vt220_emit(request));
 132         if (request == NULL && sclp_vt220_flush_later)
 133                 sclp_vt220_emit_current();
 134         /* Check if the tty needs a wake up call */
 135         if (sclp_vt220_tty != NULL) {
 136                 tty_wakeup(sclp_vt220_tty);
 137         }
 138 }
 139
 140 #define SCLP_BUFFER_MAX_RETRY           1
 141
 142 /*
 143  * Callback through which the result of a write request is reported by the
 144  * SCLP.
 145  */
 146 static void
 147 sclp_vt220_callback(struct sclp_req *request, void *data)
 148 {
 149         struct sclp_vt220_request *vt220_request;
 150         struct sclp_vt220_sccb *sccb;
 151
 152         vt220_request = (struct sclp_vt220_request *) data;
 153         if (request->status == SCLP_REQ_FAILED) {
 154                 sclp_vt220_process_queue(vt220_request);
 155                 return;
 156         }
 157         sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
 158
 159         /* Check SCLP response code and choose suitable action  */
 160         switch (sccb->header.response_code) {
 161         case 0x0020 :
 162                 break;
 163
 164         case 0x05f0: /* Target resource in improper state */
 165                 break;
 166
 167         case 0x0340: /* Contained SCLP equipment check */
 168                 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
 169                         break;
 170                 /* Remove processed buffers and requeue rest */
 171                 if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
 172                         /* Not all buffers were processed */
 173                         sccb->header.response_code = 0x0000;
 174                         vt220_request->sclp_req.status = SCLP_REQ_FILLED;
 175                         if (sclp_add_request(request) == 0)
 176                                 return;
 177                 }
 178                 break;
 179
 180         case 0x0040: /* SCLP equipment check */
 181                 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
 182                         break;
 183                 sccb->header.response_code = 0x0000;
 184                 vt220_request->sclp_req.status = SCLP_REQ_FILLED;
 185                 if (sclp_add_request(request) == 0)
 186                         return;
 187                 break;
 188
 189         default:
 190                 break;
 191         }
 192         sclp_vt220_process_queue(vt220_request);
 193 }
 194
 195 /*
 196  * Emit vt220 request buffer to SCLP. Return zero on success, non-zero
 197  * otherwise.
 198  */
 199 static int
 200 __sclp_vt220_emit(struct sclp_vt220_request *request)
 201 {
 202         if (!(sclp_vt220_register.sclp_receive_mask & EVTYP_VT220MSG_MASK)) {
 203                 request->sclp_req.status = SCLP_REQ_FAILED;
 204                 return -EIO;
 205         }
 206         request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
 207         request->sclp_req.status = SCLP_REQ_FILLED;
 208         request->sclp_req.callback = sclp_vt220_callback;
 209         request->sclp_req.callback_data = (void *) request;
 210
 211         return sclp_add_request(&request->sclp_req);
 212 }
 213
 214 /*
 215  * Queue and emit given request.
 216  */
 217 static void
 218 sclp_vt220_emit(struct sclp_vt220_request *request)
 219 {
 220         unsigned long flags;
 221         int count;
 222
 223         spin_lock_irqsave(&sclp_vt220_lock, flags);
 224         list_add_tail(&request->list, &sclp_vt220_outqueue);
 225         count = sclp_vt220_outqueue_count++;
 226         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 227         /* Emit only the first buffer immediately - callback takes care of
 228          * the rest */
 229         if (count == 0 && __sclp_vt220_emit(request))
 230                 sclp_vt220_process_queue(request);
 231 }
 232
 233 /*
 234  * Queue and emit current request. Return zero on success, non-zero otherwise.
 235  */
 236 static void
 237 sclp_vt220_emit_current(void)
 238 {
 239         unsigned long flags;
 240         struct sclp_vt220_request *request;
 241         struct sclp_vt220_sccb *sccb;
 242
 243         spin_lock_irqsave(&sclp_vt220_lock, flags);
 244         request = NULL;
 245         if (sclp_vt220_current_request != NULL) {
 246                 sccb = (struct sclp_vt220_sccb *)
 247                                 sclp_vt220_current_request->sclp_req.sccb;
 248                 /* Only emit buffers with content */
 249                 if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
 250                         request = sclp_vt220_current_request;
 251                         sclp_vt220_current_request = NULL;
 252                         if (timer_pending(&sclp_vt220_timer))
 253                                 del_timer(&sclp_vt220_timer);
 254                 }
 255                 sclp_vt220_flush_later = 0;
 256         }
 257         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 258         if (request != NULL)
 259                 sclp_vt220_emit(request);
 260 }
 261
 262 #define SCLP_NORMAL_WRITE       0x00
 263
 264 /*
 265  * Helper function to initialize a page with the sclp request structure.
 266  */
 267 static struct sclp_vt220_request *
 268 sclp_vt220_initialize_page(void *page)
 269 {
 270         struct sclp_vt220_request *request;
 271         struct sclp_vt220_sccb *sccb;
 272
 273         /* Place request structure at end of page */
 274         request = ((struct sclp_vt220_request *)
 275                         ((addr_t) page + PAGE_SIZE)) - 1;
 276         request->retry_count = 0;
 277         request->sclp_req.sccb = page;
 278         /* SCCB goes at start of page */
 279         sccb = (struct sclp_vt220_sccb *) page;
 280         memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
 281         sccb->header.length = sizeof(struct sclp_vt220_sccb);
 282         sccb->header.function_code = SCLP_NORMAL_WRITE;
 283         sccb->header.response_code = 0x0000;
 284         sccb->evbuf.type = EVTYP_VT220MSG;
 285         sccb->evbuf.length = sizeof(struct evbuf_header);
 286
 287         return request;
 288 }
 289
 290 static inline unsigned int
 291 sclp_vt220_space_left(struct sclp_vt220_request *request)
 292 {
 293         struct sclp_vt220_sccb *sccb;
 294         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 295         return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
 296                sccb->header.length;
 297 }
 298
 299 static inline unsigned int
 300 sclp_vt220_chars_stored(struct sclp_vt220_request *request)
 301 {
 302         struct sclp_vt220_sccb *sccb;
 303         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 304         return sccb->evbuf.length - sizeof(struct evbuf_header);
 305 }
 306
 307 /*
 308  * Add msg to buffer associated with request. Return the number of characters
 309  * added.
 310  */
 311 static int
 312 sclp_vt220_add_msg(struct sclp_vt220_request *request,
 313                    const unsigned char *msg, int count, int convertlf)
 314 {
 315         struct sclp_vt220_sccb *sccb;
 316         void *buffer;
 317         unsigned char c;
 318         int from;
 319         int to;
 320
 321         if (count > sclp_vt220_space_left(request))
 322                 count = sclp_vt220_space_left(request);
 323         if (count <= 0)
 324                 return 0;
 325
 326         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 327         buffer = (void *) ((addr_t) sccb + sccb->header.length);
 328
 329         if (convertlf) {
 330                 /* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
 331                 for (from=0, to=0;
 332                      (from < count) && (to < sclp_vt220_space_left(request));
 333                      from++) {
 334                         /* Retrieve character */
 335                         c = msg[from];
 336                         /* Perform conversion */
 337                         if (c == 0x0a) {
 338                                 if (to + 1 < sclp_vt220_space_left(request)) {
 339                                         ((unsigned char *) buffer)[to++] = c;
 340                                         ((unsigned char *) buffer)[to++] = 0x0d;
 341                                 } else
 342                                         break;
 343
 344                         } else
 345                                 ((unsigned char *) buffer)[to++] = c;
 346                 }
 347                 sccb->header.length += to;
 348                 sccb->evbuf.length += to;
 349                 return from;
 350         } else {
 351                 memcpy(buffer, (const void *) msg, count);
 352                 sccb->header.length += count;
 353                 sccb->evbuf.length += count;
 354                 return count;
 355         }
 356 }
 357
 358 /*
 359  * Emit buffer after having waited long enough for more data to arrive.
 360  */
 361 static void
 362 sclp_vt220_timeout(unsigned long data)
 363 {
 364         sclp_vt220_emit_current();
 365 }
 366
 367 #define BUFFER_MAX_DELAY        HZ/20
 368
 369 /*
 370  * Internal implementation of the write function. Write COUNT bytes of data
 371  * from memory at BUF
 372  * to the SCLP interface. In case that the data does not fit into the current
 373  * write buffer, emit the current one and allocate a new one. If there are no
 374  * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
 375  * is non-zero, the buffer will be scheduled for emitting after a timeout -
 376  * otherwise the user has to explicitly call the flush function.
 377  * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
 378  * buffer should be converted to 0x0a 0x0d. After completion, return the number
 379  * of bytes written.
 380  */
 381 static int
 382 __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
 383                    int convertlf, int may_fail)
 384 {
 385         unsigned long flags;
 386         void *page;
 387         int written;
 388         int overall_written;
 389
 390         if (count <= 0)
 391                 return 0;
 392         overall_written = 0;
 393         spin_lock_irqsave(&sclp_vt220_lock, flags);
 394         do {
 395                 /* Create an sclp output buffer if none exists yet */
 396                 if (sclp_vt220_current_request == NULL) {
 397                         while (list_empty(&sclp_vt220_empty)) {
 398                                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 399                                 if (may_fail)
 400                                         goto out;
 401                                 else
 402                                         sclp_sync_wait();
 403                                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 404                         }
 405                         page = (void *) sclp_vt220_empty.next;
 406                         list_del((struct list_head *) page);
 407                         sclp_vt220_current_request =
 408                                 sclp_vt220_initialize_page(page);
 409                 }
 410                 /* Try to write the string to the current request buffer */
 411                 written = sclp_vt220_add_msg(sclp_vt220_current_request,
 412                                              buf, count, convertlf);
 413                 overall_written += written;
 414                 if (written == count)
 415                         break;
 416                 /*
 417                  * Not all characters could be written to the current
 418                  * output buffer. Emit the buffer, create a new buffer
 419                  * and then output the rest of the string.
 420                  */
 421                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 422                 sclp_vt220_emit_current();
 423                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 424                 buf += written;
 425                 count -= written;
 426         } while (count > 0);
 427         /* Setup timer to output current console buffer after some time */
 428         if (sclp_vt220_current_request != NULL &&
 429             !timer_pending(&sclp_vt220_timer) && do_schedule) {
 430                 sclp_vt220_timer.function = sclp_vt220_timeout;
 431                 sclp_vt220_timer.data = 0UL;
 432                 sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
 433                 add_timer(&sclp_vt220_timer);
 434         }
 435         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 436 out:
 437         return overall_written;
 438 }
 439
 440 /*
 441  * This routine is called by the kernel to write a series of
 442  * characters to the tty device.  The characters may come from
 443  * user space or kernel space.  This routine will return the
 444  * number of characters actually accepted for writing.
 445  */
 446 static int
 447 sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
 448 {
 449         return __sclp_vt220_write(buf, count, 1, 0, 1);
 450 }
 451
 452 #define SCLP_VT220_SESSION_ENDED        0x01
 453 #define SCLP_VT220_SESSION_STARTED      0x80
 454 #define SCLP_VT220_SESSION_DATA         0x00
 455
 456 /*
 457  * Called by the SCLP to report incoming event buffers.
 458  */
 459 static void
 460 sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
 461 {
 462         char *buffer;
 463         unsigned int count;
 464
 465         /* Ignore input if device is not open */
 466         if (sclp_vt220_tty == NULL)
 467                 return;
 468
 469         buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
 470         count = evbuf->length - sizeof(struct evbuf_header);
 471
 472         switch (*buffer) {
 473         case SCLP_VT220_SESSION_ENDED:
 474         case SCLP_VT220_SESSION_STARTED:
 475                 break;
 476         case SCLP_VT220_SESSION_DATA:
 477                 /* Send input to line discipline */
 478                 buffer++;
 479                 count--;
 480                 tty_insert_flip_string(sclp_vt220_tty, buffer, count);
 481                 tty_flip_buffer_push(sclp_vt220_tty);
 482                 break;
 483         }
 484 }
 485
 486 /*
 487  * This routine is called when a particular tty device is opened.
 488  */
 489 static int
 490 sclp_vt220_open(struct tty_struct *tty, struct file *filp)
 491 {
 492         if (tty->count == 1) {
 493                 sclp_vt220_tty = tty;
 494                 tty->driver_data = kmalloc(SCLP_VT220_BUF_SIZE, GFP_KERNEL);
 495                 if (tty->driver_data == NULL)
 496                         return -ENOMEM;
 497                 tty->low_latency = 0;
 498         }
 499         return 0;
 500 }
 501
 502 /*
 503  * This routine is called when a particular tty device is closed.
 504  */
 505 static void
 506 sclp_vt220_close(struct tty_struct *tty, struct file *filp)
 507 {
 508         if (tty->count == 1) {
 509                 sclp_vt220_tty = NULL;
 510                 kfree(tty->driver_data);
 511                 tty->driver_data = NULL;
 512         }
 513 }
 514
 515 /*
 516  * This routine is called by the kernel to write a single
 517  * character to the tty device.  If the kernel uses this routine,
 518  * it must call the flush_chars() routine (if defined) when it is
 519  * done stuffing characters into the driver.
 520  */
 521 static int
 522 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
 523 {
 524         return __sclp_vt220_write(&ch, 1, 0, 0, 1);
 525 }
 526
 527 /*
 528  * This routine is called by the kernel after it has written a
 529  * series of characters to the tty device using put_char().
 530  */
 531 static void
 532 sclp_vt220_flush_chars(struct tty_struct *tty)
 533 {
 534         if (sclp_vt220_outqueue_count == 0)
 535                 sclp_vt220_emit_current();
 536         else
 537                 sclp_vt220_flush_later = 1;
 538 }
 539
 540 /*
 541  * This routine returns the numbers of characters the tty driver
 542  * will accept for queuing to be written.  This number is subject
 543  * to change as output buffers get emptied, or if the output flow
 544  * control is acted.
 545  */
 546 static int
 547 sclp_vt220_write_room(struct tty_struct *tty)
 548 {
 549         unsigned long flags;
 550         struct list_head *l;
 551         int count;
 552
 553         spin_lock_irqsave(&sclp_vt220_lock, flags);
 554         count = 0;
 555         if (sclp_vt220_current_request != NULL)
 556                 count = sclp_vt220_space_left(sclp_vt220_current_request);
 557         list_for_each(l, &sclp_vt220_empty)
 558                 count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
 559         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 560         return count;
 561 }
 562
 563 /*
 564  * Return number of buffered chars.
 565  */
 566 static int
 567 sclp_vt220_chars_in_buffer(struct tty_struct *tty)
 568 {
 569         unsigned long flags;
 570         struct list_head *l;
 571         struct sclp_vt220_request *r;
 572         int count;
 573
 574         spin_lock_irqsave(&sclp_vt220_lock, flags);
 575         count = 0;
 576         if (sclp_vt220_current_request != NULL)
 577                 count = sclp_vt220_chars_stored(sclp_vt220_current_request);
 578         list_for_each(l, &sclp_vt220_outqueue) {
 579                 r = list_entry(l, struct sclp_vt220_request, list);
 580                 count += sclp_vt220_chars_stored(r);
 581         }
 582         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 583         return count;
 584 }
 585
 586 static void
 587 __sclp_vt220_flush_buffer(void)
 588 {
 589         unsigned long flags;
 590
 591         sclp_vt220_emit_current();
 592         spin_lock_irqsave(&sclp_vt220_lock, flags);
 593         if (timer_pending(&sclp_vt220_timer))
 594                 del_timer(&sclp_vt220_timer);
 595         while (sclp_vt220_outqueue_count > 0) {
 596                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 597                 sclp_sync_wait();
 598                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 599         }
 600         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 601 }
 602
 603 /*
 604  * Pass on all buffers to the hardware. Return only when there are no more
 605  * buffers pending.
 606  */
 607 static void
 608 sclp_vt220_flush_buffer(struct tty_struct *tty)
 609 {
 610         sclp_vt220_emit_current();
 611 }
 612
 613 /* Release allocated pages. */
 614 static void __init __sclp_vt220_free_pages(void)
 615 {
 616         struct list_head *page, *p;
 617
 618         list_for_each_safe(page, p, &sclp_vt220_empty) {
 619                 list_del(page);
 620                 if (slab_is_available())
 621                         free_page((unsigned long) page);
 622                 else
 623                         free_bootmem((unsigned long) page, PAGE_SIZE);
 624         }
 625 }
 626
 627 /* Release memory and unregister from sclp core. Controlled by init counting -
 628  * only the last invoker will actually perform these actions. */
 629 static void __init __sclp_vt220_cleanup(void)
 630 {
 631         sclp_vt220_init_count--;
 632         if (sclp_vt220_init_count != 0)
 633                 return;
 634         sclp_unregister(&sclp_vt220_register);
 635         __sclp_vt220_free_pages();
 636 }
 637
 638 /* Allocate buffer pages and register with sclp core. Controlled by init
 639  * counting - only the first invoker will actually perform these actions. */
 640 static int __init __sclp_vt220_init(int num_pages)
 641 {
 642         void *page;
 643         int i;
 644         int rc;
 645
 646         sclp_vt220_init_count++;
 647         if (sclp_vt220_init_count != 1)
 648                 return 0;
 649         spin_lock_init(&sclp_vt220_lock);
 650         INIT_LIST_HEAD(&sclp_vt220_empty);
 651         INIT_LIST_HEAD(&sclp_vt220_outqueue);
 652         init_timer(&sclp_vt220_timer);
 653         sclp_vt220_current_request = NULL;
 654         sclp_vt220_buffered_chars = 0;
 655         sclp_vt220_outqueue_count = 0;
 656         sclp_vt220_tty = NULL;
 657         sclp_vt220_flush_later = 0;
 658
 659         /* Allocate pages for output buffering */
 660         for (i = 0; i < num_pages; i++) {
 661                 if (slab_is_available())
 662                         page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 663                 else
 664                         page = alloc_bootmem_low_pages(PAGE_SIZE);
 665                 if (!page) {
 666                         rc = -ENOMEM;
 667                         goto out;
 668                 }
 669                 list_add_tail((struct list_head *) page, &sclp_vt220_empty);
 670         }
 671         rc = sclp_register(&sclp_vt220_register);
 672 out:
 673         if (rc) {
 674                 __sclp_vt220_free_pages();
 675                 sclp_vt220_init_count--;
 676         }
 677         return rc;
 678 }
 679
 680 static const struct tty_operations sclp_vt220_ops = {
 681         .open = sclp_vt220_open,
 682         .close = sclp_vt220_close,
 683         .write = sclp_vt220_write,
 684         .put_char = sclp_vt220_put_char,
 685         .flush_chars = sclp_vt220_flush_chars,
 686         .write_room = sclp_vt220_write_room,
 687         .chars_in_buffer = sclp_vt220_chars_in_buffer,
 688         .flush_buffer = sclp_vt220_flush_buffer,
 689 };
 690
 691 /*
 692  * Register driver with SCLP and Linux and initialize internal tty structures.
 693  */
 694 static int __init sclp_vt220_tty_init(void)
 695 {
 696         struct tty_driver *driver;
 697         int rc;
 698
 699         /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
 700          * symmetry between VM and LPAR systems regarding ttyS1. */
 701         driver = alloc_tty_driver(1);
 702         if (!driver)
 703                 return -ENOMEM;
 704         rc = __sclp_vt220_init(MAX_KMEM_PAGES);
 705         if (rc)
 706                 goto out_driver;
 707
 708         driver->owner = THIS_MODULE;
 709         driver->driver_name = SCLP_VT220_DRIVER_NAME;
 710         driver->name = SCLP_VT220_DEVICE_NAME;
 711         driver->major = SCLP_VT220_MAJOR;
 712         driver->minor_start = SCLP_VT220_MINOR;
 713         driver->type = TTY_DRIVER_TYPE_SYSTEM;
 714         driver->subtype = SYSTEM_TYPE_TTY;
 715         driver->init_termios = tty_std_termios;
 716         driver->flags = TTY_DRIVER_REAL_RAW;
 717         tty_set_operations(driver, &sclp_vt220_ops);
 718
 719         rc = tty_register_driver(driver);
 720         if (rc)
 721                 goto out_init;
 722         sclp_vt220_driver = driver;
 723         return 0;
 724
 725 out_init:
 726         __sclp_vt220_cleanup();
 727 out_driver:
 728         put_tty_driver(driver);
 729         return rc;
 730 }
 731 __initcall(sclp_vt220_tty_init);
 732
 733 #ifdef CONFIG_SCLP_VT220_CONSOLE
 734
 735 static void
 736 sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
 737 {
 738         __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
 739 }
 740
 741 static struct tty_driver *
 742 sclp_vt220_con_device(struct console *c, int *index)
 743 {
 744         *index = 0;
 745         return sclp_vt220_driver;
 746 }
 747
 748 static int
 749 sclp_vt220_notify(struct notifier_block *self,
 750                           unsigned long event, void *data)
 751 {
 752         __sclp_vt220_flush_buffer();
 753         return NOTIFY_OK;
 754 }
 755
 756 static struct notifier_block on_panic_nb = {
 757         .notifier_call = sclp_vt220_notify,
 758         .priority = 1,
 759 };
 760
 761 static struct notifier_block on_reboot_nb = {
 762         .notifier_call = sclp_vt220_notify,
 763         .priority = 1,
 764 };
 765
 766 /* Structure needed to register with printk */
 767 static struct console sclp_vt220_console =
 768 {
 769         .name = SCLP_VT220_CONSOLE_NAME,
 770         .write = sclp_vt220_con_write,
 771         .device = sclp_vt220_con_device,
 772         .flags = CON_PRINTBUFFER,
 773         .index = SCLP_VT220_CONSOLE_INDEX
 774 };
 775
 776 static int __init
 777 sclp_vt220_con_init(void)
 778 {
 779         int rc;
 780
 781         if (!CONSOLE_IS_SCLP)
 782                 return 0;
 783         rc = __sclp_vt220_init(MAX_CONSOLE_PAGES);
 784         if (rc)
 785                 return rc;
 786         /* Attach linux console */
 787         atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
 788         register_reboot_notifier(&on_reboot_nb);
 789         register_console(&sclp_vt220_console);
 790         return 0;
 791 }
 792
 793 console_initcall(sclp_vt220_con_init);
 794 #endif /* CONFIG_SCLP_VT220_CONSOLE */
 795