drivers/s390/char/sclp_vt220.c

   1 /*
   2  * SCLP VT220 terminal driver.
   3  *
   4  * Copyright IBM Corp. 2003, 2009
   5  *
   6  * Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/list.h>
  12 #include <linux/wait.h>
  13 #include <linux/timer.h>
  14 #include <linux/kernel.h>
  15 #include <linux/tty.h>
  16 #include <linux/tty_driver.h>
  17 #include <linux/tty_flip.h>
  18 #include <linux/errno.h>
  19 #include <linux/mm.h>
  20 #include <linux/major.h>
  21 #include <linux/console.h>
  22 #include <linux/kdev_t.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/init.h>
  25 #include <linux/reboot.h>
  26 #include <linux/slab.h>
  27
  28 #include <asm/uaccess.h>
  29 #include "sclp.h"
  30
  31 #define SCLP_VT220_MAJOR                TTY_MAJOR
  32 #define SCLP_VT220_MINOR                65
  33 #define SCLP_VT220_DRIVER_NAME          "sclp_vt220"
  34 #define SCLP_VT220_DEVICE_NAME          "ttysclp"
  35 #define SCLP_VT220_CONSOLE_NAME         "ttyS"
  36 #define SCLP_VT220_CONSOLE_INDEX        1       /* console=ttyS1 */
  37
  38 /* Representation of a single write request */
  39 struct sclp_vt220_request {
  40         struct list_head list;
  41         struct sclp_req sclp_req;
  42         int retry_count;
  43 };
  44
  45 /* VT220 SCCB */
  46 struct sclp_vt220_sccb {
  47         struct sccb_header header;
  48         struct evbuf_header evbuf;
  49 };
  50
  51 #define SCLP_VT220_MAX_CHARS_PER_BUFFER (PAGE_SIZE - \
  52                                          sizeof(struct sclp_vt220_request) - \
  53                                          sizeof(struct sclp_vt220_sccb))
  54
  55 /* Structures and data needed to register tty driver */
  56 static struct tty_driver *sclp_vt220_driver;
  57
  58 static struct tty_port sclp_vt220_port;
  59
  60 /* Lock to protect internal data from concurrent access */
  61 static spinlock_t sclp_vt220_lock;
  62
  63 /* List of empty pages to be used as write request buffers */
  64 static struct list_head sclp_vt220_empty;
  65
  66 /* List of pending requests */
  67 static struct list_head sclp_vt220_outqueue;
  68
  69 /* Suspend mode flag */
  70 static int sclp_vt220_suspended;
  71
  72 /* Flag that output queue is currently running */
  73 static int sclp_vt220_queue_running;
  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 void sclp_vt220_pm_event_fn(struct sclp_register *reg,
  96                                    enum sclp_pm_event sclp_pm_event);
  97 static int __sclp_vt220_emit(struct sclp_vt220_request *request);
  98 static void sclp_vt220_emit_current(void);
  99
 100 /* Registration structure for our interest in SCLP event buffers */
 101 static struct sclp_register sclp_vt220_register = {
 102         .send_mask              = EVTYP_VT220MSG_MASK,
 103         .receive_mask           = EVTYP_VT220MSG_MASK,
 104         .state_change_fn        = NULL,
 105         .receiver_fn            = sclp_vt220_receiver_fn,
 106         .pm_event_fn            = sclp_vt220_pm_event_fn,
 107 };
 108
 109
 110 /*
 111  * Put provided request buffer back into queue and check emit pending
 112  * buffers if necessary.
 113  */
 114 static void
 115 sclp_vt220_process_queue(struct sclp_vt220_request *request)
 116 {
 117         unsigned long flags;
 118         void *page;
 119
 120         do {
 121                 /* Put buffer back to list of empty buffers */
 122                 page = request->sclp_req.sccb;
 123                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 124                 /* Move request from outqueue to empty queue */
 125                 list_del(&request->list);
 126                 list_add_tail((struct list_head *) page, &sclp_vt220_empty);
 127                 /* Check if there is a pending buffer on the out queue. */
 128                 request = NULL;
 129                 if (!list_empty(&sclp_vt220_outqueue))
 130                         request = list_entry(sclp_vt220_outqueue.next,
 131                                              struct sclp_vt220_request, list);
 132                 if (!request || sclp_vt220_suspended) {
 133                         sclp_vt220_queue_running = 0;
 134                         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 135                         break;
 136                 }
 137                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 138         } while (__sclp_vt220_emit(request));
 139         if (request == NULL && sclp_vt220_flush_later)
 140                 sclp_vt220_emit_current();
 141         tty_port_tty_wakeup(&sclp_vt220_port);
 142 }
 143
 144 #define SCLP_BUFFER_MAX_RETRY           1
 145
 146 /*
 147  * Callback through which the result of a write request is reported by the
 148  * SCLP.
 149  */
 150 static void
 151 sclp_vt220_callback(struct sclp_req *request, void *data)
 152 {
 153         struct sclp_vt220_request *vt220_request;
 154         struct sclp_vt220_sccb *sccb;
 155
 156         vt220_request = (struct sclp_vt220_request *) data;
 157         if (request->status == SCLP_REQ_FAILED) {
 158                 sclp_vt220_process_queue(vt220_request);
 159                 return;
 160         }
 161         sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
 162
 163         /* Check SCLP response code and choose suitable action  */
 164         switch (sccb->header.response_code) {
 165         case 0x0020 :
 166                 break;
 167
 168         case 0x05f0: /* Target resource in improper state */
 169                 break;
 170
 171         case 0x0340: /* Contained SCLP equipment check */
 172                 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
 173                         break;
 174                 /* Remove processed buffers and requeue rest */
 175                 if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
 176                         /* Not all buffers were processed */
 177                         sccb->header.response_code = 0x0000;
 178                         vt220_request->sclp_req.status = SCLP_REQ_FILLED;
 179                         if (sclp_add_request(request) == 0)
 180                                 return;
 181                 }
 182                 break;
 183
 184         case 0x0040: /* SCLP equipment check */
 185                 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
 186                         break;
 187                 sccb->header.response_code = 0x0000;
 188                 vt220_request->sclp_req.status = SCLP_REQ_FILLED;
 189                 if (sclp_add_request(request) == 0)
 190                         return;
 191                 break;
 192
 193         default:
 194                 break;
 195         }
 196         sclp_vt220_process_queue(vt220_request);
 197 }
 198
 199 /*
 200  * Emit vt220 request buffer to SCLP. Return zero on success, non-zero
 201  * otherwise.
 202  */
 203 static int
 204 __sclp_vt220_emit(struct sclp_vt220_request *request)
 205 {
 206         if (!(sclp_vt220_register.sclp_receive_mask & EVTYP_VT220MSG_MASK)) {
 207                 request->sclp_req.status = SCLP_REQ_FAILED;
 208                 return -EIO;
 209         }
 210         request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
 211         request->sclp_req.status = SCLP_REQ_FILLED;
 212         request->sclp_req.callback = sclp_vt220_callback;
 213         request->sclp_req.callback_data = (void *) request;
 214
 215         return sclp_add_request(&request->sclp_req);
 216 }
 217
 218 /*
 219  * Queue and emit current request.
 220  */
 221 static void
 222 sclp_vt220_emit_current(void)
 223 {
 224         unsigned long flags;
 225         struct sclp_vt220_request *request;
 226         struct sclp_vt220_sccb *sccb;
 227
 228         spin_lock_irqsave(&sclp_vt220_lock, flags);
 229         if (sclp_vt220_current_request) {
 230                 sccb = (struct sclp_vt220_sccb *)
 231                                 sclp_vt220_current_request->sclp_req.sccb;
 232                 /* Only emit buffers with content */
 233                 if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
 234                         list_add_tail(&sclp_vt220_current_request->list,
 235                                       &sclp_vt220_outqueue);
 236                         sclp_vt220_current_request = NULL;
 237                         if (timer_pending(&sclp_vt220_timer))
 238                                 del_timer(&sclp_vt220_timer);
 239                 }
 240                 sclp_vt220_flush_later = 0;
 241         }
 242         if (sclp_vt220_queue_running || sclp_vt220_suspended)
 243                 goto out_unlock;
 244         if (list_empty(&sclp_vt220_outqueue))
 245                 goto out_unlock;
 246         request = list_first_entry(&sclp_vt220_outqueue,
 247                                    struct sclp_vt220_request, list);
 248         sclp_vt220_queue_running = 1;
 249         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 250
 251         if (__sclp_vt220_emit(request))
 252                 sclp_vt220_process_queue(request);
 253         return;
 254 out_unlock:
 255         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 256 }
 257
 258 #define SCLP_NORMAL_WRITE       0x00
 259
 260 /*
 261  * Helper function to initialize a page with the sclp request structure.
 262  */
 263 static struct sclp_vt220_request *
 264 sclp_vt220_initialize_page(void *page)
 265 {
 266         struct sclp_vt220_request *request;
 267         struct sclp_vt220_sccb *sccb;
 268
 269         /* Place request structure at end of page */
 270         request = ((struct sclp_vt220_request *)
 271                         ((addr_t) page + PAGE_SIZE)) - 1;
 272         request->retry_count = 0;
 273         request->sclp_req.sccb = page;
 274         /* SCCB goes at start of page */
 275         sccb = (struct sclp_vt220_sccb *) page;
 276         memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
 277         sccb->header.length = sizeof(struct sclp_vt220_sccb);
 278         sccb->header.function_code = SCLP_NORMAL_WRITE;
 279         sccb->header.response_code = 0x0000;
 280         sccb->evbuf.type = EVTYP_VT220MSG;
 281         sccb->evbuf.length = sizeof(struct evbuf_header);
 282
 283         return request;
 284 }
 285
 286 static inline unsigned int
 287 sclp_vt220_space_left(struct sclp_vt220_request *request)
 288 {
 289         struct sclp_vt220_sccb *sccb;
 290         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 291         return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
 292                sccb->header.length;
 293 }
 294
 295 static inline unsigned int
 296 sclp_vt220_chars_stored(struct sclp_vt220_request *request)
 297 {
 298         struct sclp_vt220_sccb *sccb;
 299         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 300         return sccb->evbuf.length - sizeof(struct evbuf_header);
 301 }
 302
 303 /*
 304  * Add msg to buffer associated with request. Return the number of characters
 305  * added.
 306  */
 307 static int
 308 sclp_vt220_add_msg(struct sclp_vt220_request *request,
 309                    const unsigned char *msg, int count, int convertlf)
 310 {
 311         struct sclp_vt220_sccb *sccb;
 312         void *buffer;
 313         unsigned char c;
 314         int from;
 315         int to;
 316
 317         if (count > sclp_vt220_space_left(request))
 318                 count = sclp_vt220_space_left(request);
 319         if (count <= 0)
 320                 return 0;
 321
 322         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 323         buffer = (void *) ((addr_t) sccb + sccb->header.length);
 324
 325         if (convertlf) {
 326                 /* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
 327                 for (from=0, to=0;
 328                      (from < count) && (to < sclp_vt220_space_left(request));
 329                      from++) {
 330                         /* Retrieve character */
 331                         c = msg[from];
 332                         /* Perform conversion */
 333                         if (c == 0x0a) {
 334                                 if (to + 1 < sclp_vt220_space_left(request)) {
 335                                         ((unsigned char *) buffer)[to++] = c;
 336                                         ((unsigned char *) buffer)[to++] = 0x0d;
 337                                 } else
 338                                         break;
 339
 340                         } else
 341                                 ((unsigned char *) buffer)[to++] = c;
 342                 }
 343                 sccb->header.length += to;
 344                 sccb->evbuf.length += to;
 345                 return from;
 346         } else {
 347                 memcpy(buffer, (const void *) msg, count);
 348                 sccb->header.length += count;
 349                 sccb->evbuf.length += count;
 350                 return count;
 351         }
 352 }
 353
 354 /*
 355  * Emit buffer after having waited long enough for more data to arrive.
 356  */
 357 static void
 358 sclp_vt220_timeout(unsigned long data)
 359 {
 360         sclp_vt220_emit_current();
 361 }
 362
 363 #define BUFFER_MAX_DELAY        HZ/20
 364
 365 /*
 366  * Drop oldest console buffer if sclp_con_drop is set
 367  */
 368 static int
 369 sclp_vt220_drop_buffer(void)
 370 {
 371         struct list_head *list;
 372         struct sclp_vt220_request *request;
 373         void *page;
 374
 375         if (!sclp_console_drop)
 376                 return 0;
 377         list = sclp_vt220_outqueue.next;
 378         if (sclp_vt220_queue_running)
 379                 /* The first element is in I/O */
 380                 list = list->next;
 381         if (list == &sclp_vt220_outqueue)
 382                 return 0;
 383         list_del(list);
 384         request = list_entry(list, struct sclp_vt220_request, list);
 385         page = request->sclp_req.sccb;
 386         list_add_tail((struct list_head *) page, &sclp_vt220_empty);
 387         return 1;
 388 }
 389
 390 /*
 391  * Internal implementation of the write function. Write COUNT bytes of data
 392  * from memory at BUF
 393  * to the SCLP interface. In case that the data does not fit into the current
 394  * write buffer, emit the current one and allocate a new one. If there are no
 395  * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
 396  * is non-zero, the buffer will be scheduled for emitting after a timeout -
 397  * otherwise the user has to explicitly call the flush function.
 398  * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
 399  * buffer should be converted to 0x0a 0x0d. After completion, return the number
 400  * of bytes written.
 401  */
 402 static int
 403 __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
 404                    int convertlf, int may_fail)
 405 {
 406         unsigned long flags;
 407         void *page;
 408         int written;
 409         int overall_written;
 410
 411         if (count <= 0)
 412                 return 0;
 413         overall_written = 0;
 414         spin_lock_irqsave(&sclp_vt220_lock, flags);
 415         do {
 416                 /* Create an sclp output buffer if none exists yet */
 417                 if (sclp_vt220_current_request == NULL) {
 418                         if (list_empty(&sclp_vt220_empty))
 419                                 sclp_console_full++;
 420                         while (list_empty(&sclp_vt220_empty)) {
 421                                 if (may_fail || sclp_vt220_suspended)
 422                                         goto out;
 423                                 if (sclp_vt220_drop_buffer())
 424                                         break;
 425                                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 426
 427                                 sclp_sync_wait();
 428                                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 429                         }
 430                         page = (void *) sclp_vt220_empty.next;
 431                         list_del((struct list_head *) page);
 432                         sclp_vt220_current_request =
 433                                 sclp_vt220_initialize_page(page);
 434                 }
 435                 /* Try to write the string to the current request buffer */
 436                 written = sclp_vt220_add_msg(sclp_vt220_current_request,
 437                                              buf, count, convertlf);
 438                 overall_written += written;
 439                 if (written == count)
 440                         break;
 441                 /*
 442                  * Not all characters could be written to the current
 443                  * output buffer. Emit the buffer, create a new buffer
 444                  * and then output the rest of the string.
 445                  */
 446                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 447                 sclp_vt220_emit_current();
 448                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 449                 buf += written;
 450                 count -= written;
 451         } while (count > 0);
 452         /* Setup timer to output current console buffer after some time */
 453         if (sclp_vt220_current_request != NULL &&
 454             !timer_pending(&sclp_vt220_timer) && do_schedule) {
 455                 sclp_vt220_timer.function = sclp_vt220_timeout;
 456                 sclp_vt220_timer.data = 0UL;
 457                 sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
 458                 add_timer(&sclp_vt220_timer);
 459         }
 460 out:
 461         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 462         return overall_written;
 463 }
 464
 465 /*
 466  * This routine is called by the kernel to write a series of
 467  * characters to the tty device.  The characters may come from
 468  * user space or kernel space.  This routine will return the
 469  * number of characters actually accepted for writing.
 470  */
 471 static int
 472 sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
 473 {
 474         return __sclp_vt220_write(buf, count, 1, 0, 1);
 475 }
 476
 477 #define SCLP_VT220_SESSION_ENDED        0x01
 478 #define SCLP_VT220_SESSION_STARTED      0x80
 479 #define SCLP_VT220_SESSION_DATA         0x00
 480
 481 /*
 482  * Called by the SCLP to report incoming event buffers.
 483  */
 484 static void
 485 sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
 486 {
 487         char *buffer;
 488         unsigned int count;
 489
 490         buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
 491         count = evbuf->length - sizeof(struct evbuf_header);
 492
 493         switch (*buffer) {
 494         case SCLP_VT220_SESSION_ENDED:
 495         case SCLP_VT220_SESSION_STARTED:
 496                 break;
 497         case SCLP_VT220_SESSION_DATA:
 498                 /* Send input to line discipline */
 499                 buffer++;
 500                 count--;
 501                 tty_insert_flip_string(&sclp_vt220_port, buffer, count);
 502                 tty_flip_buffer_push(&sclp_vt220_port);
 503                 break;
 504         }
 505 }
 506
 507 /*
 508  * This routine is called when a particular tty device is opened.
 509  */
 510 static int
 511 sclp_vt220_open(struct tty_struct *tty, struct file *filp)
 512 {
 513         if (tty->count == 1) {
 514                 tty_port_tty_set(&sclp_vt220_port, tty);
 515                 sclp_vt220_port.low_latency = 0;
 516                 if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
 517                         tty->winsize.ws_row = 24;
 518                         tty->winsize.ws_col = 80;
 519                 }
 520         }
 521         return 0;
 522 }
 523
 524 /*
 525  * This routine is called when a particular tty device is closed.
 526  */
 527 static void
 528 sclp_vt220_close(struct tty_struct *tty, struct file *filp)
 529 {
 530         if (tty->count == 1)
 531                 tty_port_tty_set(&sclp_vt220_port, NULL);
 532 }
 533
 534 /*
 535  * This routine is called by the kernel to write a single
 536  * character to the tty device.  If the kernel uses this routine,
 537  * it must call the flush_chars() routine (if defined) when it is
 538  * done stuffing characters into the driver.
 539  */
 540 static int
 541 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
 542 {
 543         return __sclp_vt220_write(&ch, 1, 0, 0, 1);
 544 }
 545
 546 /*
 547  * This routine is called by the kernel after it has written a
 548  * series of characters to the tty device using put_char().
 549  */
 550 static void
 551 sclp_vt220_flush_chars(struct tty_struct *tty)
 552 {
 553         if (!sclp_vt220_queue_running)
 554                 sclp_vt220_emit_current();
 555         else
 556                 sclp_vt220_flush_later = 1;
 557 }
 558
 559 /*
 560  * This routine returns the numbers of characters the tty driver
 561  * will accept for queuing to be written.  This number is subject
 562  * to change as output buffers get emptied, or if the output flow
 563  * control is acted.
 564  */
 565 static int
 566 sclp_vt220_write_room(struct tty_struct *tty)
 567 {
 568         unsigned long flags;
 569         struct list_head *l;
 570         int count;
 571
 572         spin_lock_irqsave(&sclp_vt220_lock, flags);
 573         count = 0;
 574         if (sclp_vt220_current_request != NULL)
 575                 count = sclp_vt220_space_left(sclp_vt220_current_request);
 576         list_for_each(l, &sclp_vt220_empty)
 577                 count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
 578         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 579         return count;
 580 }
 581
 582 /*
 583  * Return number of buffered chars.
 584  */
 585 static int
 586 sclp_vt220_chars_in_buffer(struct tty_struct *tty)
 587 {
 588         unsigned long flags;
 589         struct list_head *l;
 590         struct sclp_vt220_request *r;
 591         int count;
 592
 593         spin_lock_irqsave(&sclp_vt220_lock, flags);
 594         count = 0;
 595         if (sclp_vt220_current_request != NULL)
 596                 count = sclp_vt220_chars_stored(sclp_vt220_current_request);
 597         list_for_each(l, &sclp_vt220_outqueue) {
 598                 r = list_entry(l, struct sclp_vt220_request, list);
 599                 count += sclp_vt220_chars_stored(r);
 600         }
 601         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 602         return count;
 603 }
 604
 605 /*
 606  * Pass on all buffers to the hardware. Return only when there are no more
 607  * buffers pending.
 608  */
 609 static void
 610 sclp_vt220_flush_buffer(struct tty_struct *tty)
 611 {
 612         sclp_vt220_emit_current();
 613 }
 614
 615 /* Release allocated pages. */
 616 static void __init __sclp_vt220_free_pages(void)
 617 {
 618         struct list_head *page, *p;
 619
 620         list_for_each_safe(page, p, &sclp_vt220_empty) {
 621                 list_del(page);
 622                 free_page((unsigned long) page);
 623         }
 624 }
 625
 626 /* Release memory and unregister from sclp core. Controlled by init counting -
 627  * only the last invoker will actually perform these actions. */
 628 static void __init __sclp_vt220_cleanup(void)
 629 {
 630         sclp_vt220_init_count--;
 631         if (sclp_vt220_init_count != 0)
 632                 return;
 633         sclp_unregister(&sclp_vt220_register);
 634         __sclp_vt220_free_pages();
 635         tty_port_destroy(&sclp_vt220_port);
 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         tty_port_init(&sclp_vt220_port);
 654         sclp_vt220_current_request = NULL;
 655         sclp_vt220_buffered_chars = 0;
 656         sclp_vt220_flush_later = 0;
 657
 658         /* Allocate pages for output buffering */
 659         rc = -ENOMEM;
 660         for (i = 0; i < num_pages; i++) {
 661                 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 662                 if (!page)
 663                         goto out;
 664                 list_add_tail(page, &sclp_vt220_empty);
 665         }
 666         rc = sclp_register(&sclp_vt220_register);
 667 out:
 668         if (rc) {
 669                 __sclp_vt220_free_pages();
 670                 sclp_vt220_init_count--;
 671                 tty_port_destroy(&sclp_vt220_port);
 672         }
 673         return rc;
 674 }
 675
 676 static const struct tty_operations sclp_vt220_ops = {
 677         .open = sclp_vt220_open,
 678         .close = sclp_vt220_close,
 679         .write = sclp_vt220_write,
 680         .put_char = sclp_vt220_put_char,
 681         .flush_chars = sclp_vt220_flush_chars,
 682         .write_room = sclp_vt220_write_room,
 683         .chars_in_buffer = sclp_vt220_chars_in_buffer,
 684         .flush_buffer = sclp_vt220_flush_buffer,
 685 };
 686
 687 /*
 688  * Register driver with SCLP and Linux and initialize internal tty structures.
 689  */
 690 static int __init sclp_vt220_tty_init(void)
 691 {
 692         struct tty_driver *driver;
 693         int rc;
 694
 695         /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
 696          * symmetry between VM and LPAR systems regarding ttyS1. */
 697         driver = alloc_tty_driver(1);
 698         if (!driver)
 699                 return -ENOMEM;
 700         rc = __sclp_vt220_init(MAX_KMEM_PAGES);
 701         if (rc)
 702                 goto out_driver;
 703
 704         driver->driver_name = SCLP_VT220_DRIVER_NAME;
 705         driver->name = SCLP_VT220_DEVICE_NAME;
 706         driver->major = SCLP_VT220_MAJOR;
 707         driver->minor_start = SCLP_VT220_MINOR;
 708         driver->type = TTY_DRIVER_TYPE_SYSTEM;
 709         driver->subtype = SYSTEM_TYPE_TTY;
 710         driver->init_termios = tty_std_termios;
 711         driver->flags = TTY_DRIVER_REAL_RAW;
 712         tty_set_operations(driver, &sclp_vt220_ops);
 713         tty_port_link_device(&sclp_vt220_port, driver, 0);
 714
 715         rc = tty_register_driver(driver);
 716         if (rc)
 717                 goto out_init;
 718         sclp_vt220_driver = driver;
 719         return 0;
 720
 721 out_init:
 722         __sclp_vt220_cleanup();
 723 out_driver:
 724         put_tty_driver(driver);
 725         return rc;
 726 }
 727 __initcall(sclp_vt220_tty_init);
 728
 729 static void __sclp_vt220_flush_buffer(void)
 730 {
 731         unsigned long flags;
 732
 733         sclp_vt220_emit_current();
 734         spin_lock_irqsave(&sclp_vt220_lock, flags);
 735         if (timer_pending(&sclp_vt220_timer))
 736                 del_timer(&sclp_vt220_timer);
 737         while (sclp_vt220_queue_running) {
 738                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 739                 sclp_sync_wait();
 740                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 741         }
 742         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 743 }
 744
 745 /*
 746  * Resume console: If there are cached messages, emit them.
 747  */
 748 static void sclp_vt220_resume(void)
 749 {
 750         unsigned long flags;
 751
 752         spin_lock_irqsave(&sclp_vt220_lock, flags);
 753         sclp_vt220_suspended = 0;
 754         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 755         sclp_vt220_emit_current();
 756 }
 757
 758 /*
 759  * Suspend console: Set suspend flag and flush console
 760  */
 761 static void sclp_vt220_suspend(void)
 762 {
 763         unsigned long flags;
 764
 765         spin_lock_irqsave(&sclp_vt220_lock, flags);
 766         sclp_vt220_suspended = 1;
 767         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 768         __sclp_vt220_flush_buffer();
 769 }
 770
 771 static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
 772                                    enum sclp_pm_event sclp_pm_event)
 773 {
 774         switch (sclp_pm_event) {
 775         case SCLP_PM_EVENT_FREEZE:
 776                 sclp_vt220_suspend();
 777                 break;
 778         case SCLP_PM_EVENT_RESTORE:
 779         case SCLP_PM_EVENT_THAW:
 780                 sclp_vt220_resume();
 781                 break;
 782         }
 783 }
 784
 785 #ifdef CONFIG_SCLP_VT220_CONSOLE
 786
 787 static void
 788 sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
 789 {
 790         __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
 791 }
 792
 793 static struct tty_driver *
 794 sclp_vt220_con_device(struct console *c, int *index)
 795 {
 796         *index = 0;
 797         return sclp_vt220_driver;
 798 }
 799
 800 static int
 801 sclp_vt220_notify(struct notifier_block *self,
 802                           unsigned long event, void *data)
 803 {
 804         __sclp_vt220_flush_buffer();
 805         return NOTIFY_OK;
 806 }
 807
 808 static struct notifier_block on_panic_nb = {
 809         .notifier_call = sclp_vt220_notify,
 810         .priority = 1,
 811 };
 812
 813 static struct notifier_block on_reboot_nb = {
 814         .notifier_call = sclp_vt220_notify,
 815         .priority = 1,
 816 };
 817
 818 /* Structure needed to register with printk */
 819 static struct console sclp_vt220_console =
 820 {
 821         .name = SCLP_VT220_CONSOLE_NAME,
 822         .write = sclp_vt220_con_write,
 823         .device = sclp_vt220_con_device,
 824         .flags = CON_PRINTBUFFER,
 825         .index = SCLP_VT220_CONSOLE_INDEX
 826 };
 827
 828 static int __init
 829 sclp_vt220_con_init(void)
 830 {
 831         int rc;
 832
 833         if (!CONSOLE_IS_SCLP)
 834                 return 0;
 835         rc = __sclp_vt220_init(sclp_console_pages);
 836         if (rc)
 837                 return rc;
 838         /* Attach linux console */
 839         atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
 840         register_reboot_notifier(&on_reboot_nb);
 841         register_console(&sclp_vt220_console);
 842         return 0;
 843 }
 844
 845 console_initcall(sclp_vt220_con_init);
 846 #endif /* CONFIG_SCLP_VT220_CONSOLE */
 847