kernel/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 SCLP output event buffers */
 101 static struct sclp_register sclp_vt220_register = {
 102         .send_mask              = EVTYP_VT220MSG_MASK,
 103         .pm_event_fn            = sclp_vt220_pm_event_fn,
 104 };
 105
 106 /* Registration structure for SCLP input event buffers */
 107 static struct sclp_register sclp_vt220_register_input = {
 108         .receive_mask           = EVTYP_VT220MSG_MASK,
 109         .receiver_fn            = sclp_vt220_receiver_fn,
 110 };
 111
 112
 113 /*
 114  * Put provided request buffer back into queue and check emit pending
 115  * buffers if necessary.
 116  */
 117 static void
 118 sclp_vt220_process_queue(struct sclp_vt220_request *request)
 119 {
 120         unsigned long flags;
 121         void *page;
 122
 123         do {
 124                 /* Put buffer back to list of empty buffers */
 125                 page = request->sclp_req.sccb;
 126                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 127                 /* Move request from outqueue to empty queue */
 128                 list_del(&request->list);
 129                 list_add_tail((struct list_head *) page, &sclp_vt220_empty);
 130                 /* Check if there is a pending buffer on the out queue. */
 131                 request = NULL;
 132                 if (!list_empty(&sclp_vt220_outqueue))
 133                         request = list_entry(sclp_vt220_outqueue.next,
 134                                              struct sclp_vt220_request, list);
 135                 if (!request || sclp_vt220_suspended) {
 136                         sclp_vt220_queue_running = 0;
 137                         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 138                         break;
 139                 }
 140                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 141         } while (__sclp_vt220_emit(request));
 142         if (request == NULL && sclp_vt220_flush_later)
 143                 sclp_vt220_emit_current();
 144         tty_port_tty_wakeup(&sclp_vt220_port);
 145 }
 146
 147 #define SCLP_BUFFER_MAX_RETRY           1
 148
 149 /*
 150  * Callback through which the result of a write request is reported by the
 151  * SCLP.
 152  */
 153 static void
 154 sclp_vt220_callback(struct sclp_req *request, void *data)
 155 {
 156         struct sclp_vt220_request *vt220_request;
 157         struct sclp_vt220_sccb *sccb;
 158
 159         vt220_request = (struct sclp_vt220_request *) data;
 160         if (request->status == SCLP_REQ_FAILED) {
 161                 sclp_vt220_process_queue(vt220_request);
 162                 return;
 163         }
 164         sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
 165
 166         /* Check SCLP response code and choose suitable action  */
 167         switch (sccb->header.response_code) {
 168         case 0x0020 :
 169                 break;
 170
 171         case 0x05f0: /* Target resource in improper state */
 172                 break;
 173
 174         case 0x0340: /* Contained SCLP equipment check */
 175                 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
 176                         break;
 177                 /* Remove processed buffers and requeue rest */
 178                 if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
 179                         /* Not all buffers were processed */
 180                         sccb->header.response_code = 0x0000;
 181                         vt220_request->sclp_req.status = SCLP_REQ_FILLED;
 182                         if (sclp_add_request(request) == 0)
 183                                 return;
 184                 }
 185                 break;
 186
 187         case 0x0040: /* SCLP equipment check */
 188                 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
 189                         break;
 190                 sccb->header.response_code = 0x0000;
 191                 vt220_request->sclp_req.status = SCLP_REQ_FILLED;
 192                 if (sclp_add_request(request) == 0)
 193                         return;
 194                 break;
 195
 196         default:
 197                 break;
 198         }
 199         sclp_vt220_process_queue(vt220_request);
 200 }
 201
 202 /*
 203  * Emit vt220 request buffer to SCLP. Return zero on success, non-zero
 204  * otherwise.
 205  */
 206 static int
 207 __sclp_vt220_emit(struct sclp_vt220_request *request)
 208 {
 209         request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
 210         request->sclp_req.status = SCLP_REQ_FILLED;
 211         request->sclp_req.callback = sclp_vt220_callback;
 212         request->sclp_req.callback_data = (void *) request;
 213
 214         return sclp_add_request(&request->sclp_req);
 215 }
 216
 217 /*
 218  * Queue and emit current request.
 219  */
 220 static void
 221 sclp_vt220_emit_current(void)
 222 {
 223         unsigned long flags;
 224         struct sclp_vt220_request *request;
 225         struct sclp_vt220_sccb *sccb;
 226
 227         spin_lock_irqsave(&sclp_vt220_lock, flags);
 228         if (sclp_vt220_current_request) {
 229                 sccb = (struct sclp_vt220_sccb *)
 230                                 sclp_vt220_current_request->sclp_req.sccb;
 231                 /* Only emit buffers with content */
 232                 if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
 233                         list_add_tail(&sclp_vt220_current_request->list,
 234                                       &sclp_vt220_outqueue);
 235                         sclp_vt220_current_request = NULL;
 236                         if (timer_pending(&sclp_vt220_timer))
 237                                 del_timer(&sclp_vt220_timer);
 238                 }
 239                 sclp_vt220_flush_later = 0;
 240         }
 241         if (sclp_vt220_queue_running || sclp_vt220_suspended)
 242                 goto out_unlock;
 243         if (list_empty(&sclp_vt220_outqueue))
 244                 goto out_unlock;
 245         request = list_first_entry(&sclp_vt220_outqueue,
 246                                    struct sclp_vt220_request, list);
 247         sclp_vt220_queue_running = 1;
 248         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 249
 250         if (__sclp_vt220_emit(request))
 251                 sclp_vt220_process_queue(request);
 252         return;
 253 out_unlock:
 254         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 255 }
 256
 257 #define SCLP_NORMAL_WRITE       0x00
 258
 259 /*
 260  * Helper function to initialize a page with the sclp request structure.
 261  */
 262 static struct sclp_vt220_request *
 263 sclp_vt220_initialize_page(void *page)
 264 {
 265         struct sclp_vt220_request *request;
 266         struct sclp_vt220_sccb *sccb;
 267
 268         /* Place request structure at end of page */
 269         request = ((struct sclp_vt220_request *)
 270                         ((addr_t) page + PAGE_SIZE)) - 1;
 271         request->retry_count = 0;
 272         request->sclp_req.sccb = page;
 273         /* SCCB goes at start of page */
 274         sccb = (struct sclp_vt220_sccb *) page;
 275         memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
 276         sccb->header.length = sizeof(struct sclp_vt220_sccb);
 277         sccb->header.function_code = SCLP_NORMAL_WRITE;
 278         sccb->header.response_code = 0x0000;
 279         sccb->evbuf.type = EVTYP_VT220MSG;
 280         sccb->evbuf.length = sizeof(struct evbuf_header);
 281
 282         return request;
 283 }
 284
 285 static inline unsigned int
 286 sclp_vt220_space_left(struct sclp_vt220_request *request)
 287 {
 288         struct sclp_vt220_sccb *sccb;
 289         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 290         return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
 291                sccb->header.length;
 292 }
 293
 294 static inline unsigned int
 295 sclp_vt220_chars_stored(struct sclp_vt220_request *request)
 296 {
 297         struct sclp_vt220_sccb *sccb;
 298         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 299         return sccb->evbuf.length - sizeof(struct evbuf_header);
 300 }
 301
 302 /*
 303  * Add msg to buffer associated with request. Return the number of characters
 304  * added.
 305  */
 306 static int
 307 sclp_vt220_add_msg(struct sclp_vt220_request *request,
 308                    const unsigned char *msg, int count, int convertlf)
 309 {
 310         struct sclp_vt220_sccb *sccb;
 311         void *buffer;
 312         unsigned char c;
 313         int from;
 314         int to;
 315
 316         if (count > sclp_vt220_space_left(request))
 317                 count = sclp_vt220_space_left(request);
 318         if (count <= 0)
 319                 return 0;
 320
 321         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 322         buffer = (void *) ((addr_t) sccb + sccb->header.length);
 323
 324         if (convertlf) {
 325                 /* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
 326                 for (from=0, to=0;
 327                      (from < count) && (to < sclp_vt220_space_left(request));
 328                      from++) {
 329                         /* Retrieve character */
 330                         c = msg[from];
 331                         /* Perform conversion */
 332                         if (c == 0x0a) {
 333                                 if (to + 1 < sclp_vt220_space_left(request)) {
 334                                         ((unsigned char *) buffer)[to++] = c;
 335                                         ((unsigned char *) buffer)[to++] = 0x0d;
 336                                 } else
 337                                         break;
 338
 339                         } else
 340                                 ((unsigned char *) buffer)[to++] = c;
 341                 }
 342                 sccb->header.length += to;
 343                 sccb->evbuf.length += to;
 344                 return from;
 345         } else {
 346                 memcpy(buffer, (const void *) msg, count);
 347                 sccb->header.length += count;
 348                 sccb->evbuf.length += count;
 349                 return count;
 350         }
 351 }
 352
 353 /*
 354  * Emit buffer after having waited long enough for more data to arrive.
 355  */
 356 static void
 357 sclp_vt220_timeout(unsigned long data)
 358 {
 359         sclp_vt220_emit_current();
 360 }
 361
 362 #define BUFFER_MAX_DELAY        HZ/20
 363
 364 /*
 365  * Drop oldest console buffer if sclp_con_drop is set
 366  */
 367 static int
 368 sclp_vt220_drop_buffer(void)
 369 {
 370         struct list_head *list;
 371         struct sclp_vt220_request *request;
 372         void *page;
 373
 374         if (!sclp_console_drop)
 375                 return 0;
 376         list = sclp_vt220_outqueue.next;
 377         if (sclp_vt220_queue_running)
 378                 /* The first element is in I/O */
 379                 list = list->next;
 380         if (list == &sclp_vt220_outqueue)
 381                 return 0;
 382         list_del(list);
 383         request = list_entry(list, struct sclp_vt220_request, list);
 384         page = request->sclp_req.sccb;
 385         list_add_tail((struct list_head *) page, &sclp_vt220_empty);
 386         return 1;
 387 }
 388
 389 /*
 390  * Internal implementation of the write function. Write COUNT bytes of data
 391  * from memory at BUF
 392  * to the SCLP interface. In case that the data does not fit into the current
 393  * write buffer, emit the current one and allocate a new one. If there are no
 394  * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
 395  * is non-zero, the buffer will be scheduled for emitting after a timeout -
 396  * otherwise the user has to explicitly call the flush function.
 397  * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
 398  * buffer should be converted to 0x0a 0x0d. After completion, return the number
 399  * of bytes written.
 400  */
 401 static int
 402 __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
 403                    int convertlf, int may_fail)
 404 {
 405         unsigned long flags;
 406         void *page;
 407         int written;
 408         int overall_written;
 409
 410         if (count <= 0)
 411                 return 0;
 412         overall_written = 0;
 413         spin_lock_irqsave(&sclp_vt220_lock, flags);
 414         do {
 415                 /* Create an sclp output buffer if none exists yet */
 416                 if (sclp_vt220_current_request == NULL) {
 417                         if (list_empty(&sclp_vt220_empty))
 418                                 sclp_console_full++;
 419                         while (list_empty(&sclp_vt220_empty)) {
 420                                 if (may_fail || sclp_vt220_suspended)
 421                                         goto out;
 422                                 if (sclp_vt220_drop_buffer())
 423                                         break;
 424                                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 425
 426                                 sclp_sync_wait();
 427                                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 428                         }
 429                         page = (void *) sclp_vt220_empty.next;
 430                         list_del((struct list_head *) page);
 431                         sclp_vt220_current_request =
 432                                 sclp_vt220_initialize_page(page);
 433                 }
 434                 /* Try to write the string to the current request buffer */
 435                 written = sclp_vt220_add_msg(sclp_vt220_current_request,
 436                                              buf, count, convertlf);
 437                 overall_written += written;
 438                 if (written == count)
 439                         break;
 440                 /*
 441                  * Not all characters could be written to the current
 442                  * output buffer. Emit the buffer, create a new buffer
 443                  * and then output the rest of the string.
 444                  */
 445                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 446                 sclp_vt220_emit_current();
 447                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 448                 buf += written;
 449                 count -= written;
 450         } while (count > 0);
 451         /* Setup timer to output current console buffer after some time */
 452         if (sclp_vt220_current_request != NULL &&
 453             !timer_pending(&sclp_vt220_timer) && do_schedule) {
 454                 sclp_vt220_timer.function = sclp_vt220_timeout;
 455                 sclp_vt220_timer.data = 0UL;
 456                 sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
 457                 add_timer(&sclp_vt220_timer);
 458         }
 459 out:
 460         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 461         return overall_written;
 462 }
 463
 464 /*
 465  * This routine is called by the kernel to write a series of
 466  * characters to the tty device.  The characters may come from
 467  * user space or kernel space.  This routine will return the
 468  * number of characters actually accepted for writing.
 469  */
 470 static int
 471 sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
 472 {
 473         return __sclp_vt220_write(buf, count, 1, 0, 1);
 474 }
 475
 476 #define SCLP_VT220_SESSION_ENDED        0x01
 477 #define SCLP_VT220_SESSION_STARTED      0x80
 478 #define SCLP_VT220_SESSION_DATA         0x00
 479
 480 /*
 481  * Called by the SCLP to report incoming event buffers.
 482  */
 483 static void
 484 sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
 485 {
 486         char *buffer;
 487         unsigned int count;
 488
 489         buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
 490         count = evbuf->length - sizeof(struct evbuf_header);
 491
 492         switch (*buffer) {
 493         case SCLP_VT220_SESSION_ENDED:
 494         case SCLP_VT220_SESSION_STARTED:
 495                 break;
 496         case SCLP_VT220_SESSION_DATA:
 497                 /* Send input to line discipline */
 498                 buffer++;
 499                 count--;
 500                 tty_insert_flip_string(&sclp_vt220_port, buffer, count);
 501                 tty_flip_buffer_push(&sclp_vt220_port);
 502                 break;
 503         }
 504 }
 505
 506 /*
 507  * This routine is called when a particular tty device is opened.
 508  */
 509 static int
 510 sclp_vt220_open(struct tty_struct *tty, struct file *filp)
 511 {
 512         if (tty->count == 1) {
 513                 tty_port_tty_set(&sclp_vt220_port, tty);
 514                 sclp_vt220_port.low_latency = 0;
 515                 if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
 516                         tty->winsize.ws_row = 24;
 517                         tty->winsize.ws_col = 80;
 518                 }
 519         }
 520         return 0;
 521 }
 522
 523 /*
 524  * This routine is called when a particular tty device is closed.
 525  */
 526 static void
 527 sclp_vt220_close(struct tty_struct *tty, struct file *filp)
 528 {
 529         if (tty->count == 1)
 530                 tty_port_tty_set(&sclp_vt220_port, NULL);
 531 }
 532
 533 /*
 534  * This routine is called by the kernel to write a single
 535  * character to the tty device.  If the kernel uses this routine,
 536  * it must call the flush_chars() routine (if defined) when it is
 537  * done stuffing characters into the driver.
 538  */
 539 static int
 540 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
 541 {
 542         return __sclp_vt220_write(&ch, 1, 0, 0, 1);
 543 }
 544
 545 /*
 546  * This routine is called by the kernel after it has written a
 547  * series of characters to the tty device using put_char().
 548  */
 549 static void
 550 sclp_vt220_flush_chars(struct tty_struct *tty)
 551 {
 552         if (!sclp_vt220_queue_running)
 553                 sclp_vt220_emit_current();
 554         else
 555                 sclp_vt220_flush_later = 1;
 556 }
 557
 558 /*
 559  * This routine returns the numbers of characters the tty driver
 560  * will accept for queuing to be written.  This number is subject
 561  * to change as output buffers get emptied, or if the output flow
 562  * control is acted.
 563  */
 564 static int
 565 sclp_vt220_write_room(struct tty_struct *tty)
 566 {
 567         unsigned long flags;
 568         struct list_head *l;
 569         int count;
 570
 571         spin_lock_irqsave(&sclp_vt220_lock, flags);
 572         count = 0;
 573         if (sclp_vt220_current_request != NULL)
 574                 count = sclp_vt220_space_left(sclp_vt220_current_request);
 575         list_for_each(l, &sclp_vt220_empty)
 576                 count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
 577         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 578         return count;
 579 }
 580
 581 /*
 582  * Return number of buffered chars.
 583  */
 584 static int
 585 sclp_vt220_chars_in_buffer(struct tty_struct *tty)
 586 {
 587         unsigned long flags;
 588         struct list_head *l;
 589         struct sclp_vt220_request *r;
 590         int count;
 591
 592         spin_lock_irqsave(&sclp_vt220_lock, flags);
 593         count = 0;
 594         if (sclp_vt220_current_request != NULL)
 595                 count = sclp_vt220_chars_stored(sclp_vt220_current_request);
 596         list_for_each(l, &sclp_vt220_outqueue) {
 597                 r = list_entry(l, struct sclp_vt220_request, list);
 598                 count += sclp_vt220_chars_stored(r);
 599         }
 600         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 601         return count;
 602 }
 603
 604 /*
 605  * Pass on all buffers to the hardware. Return only when there are no more
 606  * buffers pending.
 607  */
 608 static void
 609 sclp_vt220_flush_buffer(struct tty_struct *tty)
 610 {
 611         sclp_vt220_emit_current();
 612 }
 613
 614 /* Release allocated pages. */
 615 static void __init __sclp_vt220_free_pages(void)
 616 {
 617         struct list_head *page, *p;
 618
 619         list_for_each_safe(page, p, &sclp_vt220_empty) {
 620                 list_del(page);
 621                 free_page((unsigned long) page);
 622         }
 623 }
 624
 625 /* Release memory and unregister from sclp core. Controlled by init counting -
 626  * only the last invoker will actually perform these actions. */
 627 static void __init __sclp_vt220_cleanup(void)
 628 {
 629         sclp_vt220_init_count--;
 630         if (sclp_vt220_init_count != 0)
 631                 return;
 632         sclp_unregister(&sclp_vt220_register);
 633         __sclp_vt220_free_pages();
 634         tty_port_destroy(&sclp_vt220_port);
 635 }
 636
 637 /* Allocate buffer pages and register with sclp core. Controlled by init
 638  * counting - only the first invoker will actually perform these actions. */
 639 static int __init __sclp_vt220_init(int num_pages)
 640 {
 641         void *page;
 642         int i;
 643         int rc;
 644
 645         sclp_vt220_init_count++;
 646         if (sclp_vt220_init_count != 1)
 647                 return 0;
 648         spin_lock_init(&sclp_vt220_lock);
 649         INIT_LIST_HEAD(&sclp_vt220_empty);
 650         INIT_LIST_HEAD(&sclp_vt220_outqueue);
 651         init_timer(&sclp_vt220_timer);
 652         tty_port_init(&sclp_vt220_port);
 653         sclp_vt220_current_request = NULL;
 654         sclp_vt220_buffered_chars = 0;
 655         sclp_vt220_flush_later = 0;
 656
 657         /* Allocate pages for output buffering */
 658         rc = -ENOMEM;
 659         for (i = 0; i < num_pages; i++) {
 660                 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 661                 if (!page)
 662                         goto out;
 663                 list_add_tail(page, &sclp_vt220_empty);
 664         }
 665         rc = sclp_register(&sclp_vt220_register);
 666 out:
 667         if (rc) {
 668                 __sclp_vt220_free_pages();
 669                 sclp_vt220_init_count--;
 670                 tty_port_destroy(&sclp_vt220_port);
 671         }
 672         return rc;
 673 }
 674
 675 static const struct tty_operations sclp_vt220_ops = {
 676         .open = sclp_vt220_open,
 677         .close = sclp_vt220_close,
 678         .write = sclp_vt220_write,
 679         .put_char = sclp_vt220_put_char,
 680         .flush_chars = sclp_vt220_flush_chars,
 681         .write_room = sclp_vt220_write_room,
 682         .chars_in_buffer = sclp_vt220_chars_in_buffer,
 683         .flush_buffer = sclp_vt220_flush_buffer,
 684 };
 685
 686 /*
 687  * Register driver with SCLP and Linux and initialize internal tty structures.
 688  */
 689 static int __init sclp_vt220_tty_init(void)
 690 {
 691         struct tty_driver *driver;
 692         int rc;
 693
 694         /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
 695          * symmetry between VM and LPAR systems regarding ttyS1. */
 696         driver = alloc_tty_driver(1);
 697         if (!driver)
 698                 return -ENOMEM;
 699         rc = __sclp_vt220_init(MAX_KMEM_PAGES);
 700         if (rc)
 701                 goto out_driver;
 702
 703         driver->driver_name = SCLP_VT220_DRIVER_NAME;
 704         driver->name = SCLP_VT220_DEVICE_NAME;
 705         driver->major = SCLP_VT220_MAJOR;
 706         driver->minor_start = SCLP_VT220_MINOR;
 707         driver->type = TTY_DRIVER_TYPE_SYSTEM;
 708         driver->subtype = SYSTEM_TYPE_TTY;
 709         driver->init_termios = tty_std_termios;
 710         driver->flags = TTY_DRIVER_REAL_RAW;
 711         tty_set_operations(driver, &sclp_vt220_ops);
 712         tty_port_link_device(&sclp_vt220_port, driver, 0);
 713
 714         rc = tty_register_driver(driver);
 715         if (rc)
 716                 goto out_init;
 717         rc = sclp_register(&sclp_vt220_register_input);
 718         if (rc)
 719                 goto out_reg;
 720         sclp_vt220_driver = driver;
 721         return 0;
 722
 723 out_reg:
 724         tty_unregister_driver(driver);
 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 static void __sclp_vt220_flush_buffer(void)
 734 {
 735         unsigned long flags;
 736
 737         sclp_vt220_emit_current();
 738         spin_lock_irqsave(&sclp_vt220_lock, flags);
 739         if (timer_pending(&sclp_vt220_timer))
 740                 del_timer(&sclp_vt220_timer);
 741         while (sclp_vt220_queue_running) {
 742                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 743                 sclp_sync_wait();
 744                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 745         }
 746         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 747 }
 748
 749 /*
 750  * Resume console: If there are cached messages, emit them.
 751  */
 752 static void sclp_vt220_resume(void)
 753 {
 754         unsigned long flags;
 755
 756         spin_lock_irqsave(&sclp_vt220_lock, flags);
 757         sclp_vt220_suspended = 0;
 758         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 759         sclp_vt220_emit_current();
 760 }
 761
 762 /*
 763  * Suspend console: Set suspend flag and flush console
 764  */
 765 static void sclp_vt220_suspend(void)
 766 {
 767         unsigned long flags;
 768
 769         spin_lock_irqsave(&sclp_vt220_lock, flags);
 770         sclp_vt220_suspended = 1;
 771         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 772         __sclp_vt220_flush_buffer();
 773 }
 774
 775 static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
 776                                    enum sclp_pm_event sclp_pm_event)
 777 {
 778         switch (sclp_pm_event) {
 779         case SCLP_PM_EVENT_FREEZE:
 780                 sclp_vt220_suspend();
 781                 break;
 782         case SCLP_PM_EVENT_RESTORE:
 783         case SCLP_PM_EVENT_THAW:
 784                 sclp_vt220_resume();
 785                 break;
 786         }
 787 }
 788
 789 #ifdef CONFIG_SCLP_VT220_CONSOLE
 790
 791 static void
 792 sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
 793 {
 794         __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
 795 }
 796
 797 static struct tty_driver *
 798 sclp_vt220_con_device(struct console *c, int *index)
 799 {
 800         *index = 0;
 801         return sclp_vt220_driver;
 802 }
 803
 804 static int
 805 sclp_vt220_notify(struct notifier_block *self,
 806                           unsigned long event, void *data)
 807 {
 808         __sclp_vt220_flush_buffer();
 809         return NOTIFY_OK;
 810 }
 811
 812 static struct notifier_block on_panic_nb = {
 813         .notifier_call = sclp_vt220_notify,
 814         .priority = 1,
 815 };
 816
 817 static struct notifier_block on_reboot_nb = {
 818         .notifier_call = sclp_vt220_notify,
 819         .priority = 1,
 820 };
 821
 822 /* Structure needed to register with printk */
 823 static struct console sclp_vt220_console =
 824 {
 825         .name = SCLP_VT220_CONSOLE_NAME,
 826         .write = sclp_vt220_con_write,
 827         .device = sclp_vt220_con_device,
 828         .flags = CON_PRINTBUFFER,
 829         .index = SCLP_VT220_CONSOLE_INDEX
 830 };
 831
 832 static int __init
 833 sclp_vt220_con_init(void)
 834 {
 835         int rc;
 836
 837         rc = __sclp_vt220_init(sclp_console_pages);
 838         if (rc)
 839                 return rc;
 840         /* Attach linux console */
 841         atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
 842         register_reboot_notifier(&on_reboot_nb);
 843         register_console(&sclp_vt220_console);
 844         return 0;
 845 }
 846
 847 console_initcall(sclp_vt220_con_init);
 848 #endif /* CONFIG_SCLP_VT220_CONSOLE */
 849