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         struct tty_struct *tty;
 118         unsigned long flags;
 119         void *page;
 120
 121         do {
 122                 /* Put buffer back to list of empty buffers */
 123                 page = request->sclp_req.sccb;
 124                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 125                 /* Move request from outqueue to empty queue */
 126                 list_del(&request->list);
 127                 list_add_tail((struct list_head *) page, &sclp_vt220_empty);
 128                 /* Check if there is a pending buffer on the out queue. */
 129                 request = NULL;
 130                 if (!list_empty(&sclp_vt220_outqueue))
 131                         request = list_entry(sclp_vt220_outqueue.next,
 132                                              struct sclp_vt220_request, list);
 133                 if (!request || sclp_vt220_suspended) {
 134                         sclp_vt220_queue_running = 0;
 135                         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 136                         break;
 137                 }
 138                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 139         } while (__sclp_vt220_emit(request));
 140         if (request == NULL && sclp_vt220_flush_later)
 141                 sclp_vt220_emit_current();
 142         /* Check if the tty needs a wake up call */
 143         tty = tty_port_tty_get(&sclp_vt220_port);
 144         if (tty) {
 145                 tty_wakeup(tty);
 146                 tty_kref_put(tty);
 147         }
 148 }
 149
 150 #define SCLP_BUFFER_MAX_RETRY           1
 151
 152 /*
 153  * Callback through which the result of a write request is reported by the
 154  * SCLP.
 155  */
 156 static void
 157 sclp_vt220_callback(struct sclp_req *request, void *data)
 158 {
 159         struct sclp_vt220_request *vt220_request;
 160         struct sclp_vt220_sccb *sccb;
 161
 162         vt220_request = (struct sclp_vt220_request *) data;
 163         if (request->status == SCLP_REQ_FAILED) {
 164                 sclp_vt220_process_queue(vt220_request);
 165                 return;
 166         }
 167         sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb;
 168
 169         /* Check SCLP response code and choose suitable action  */
 170         switch (sccb->header.response_code) {
 171         case 0x0020 :
 172                 break;
 173
 174         case 0x05f0: /* Target resource in improper state */
 175                 break;
 176
 177         case 0x0340: /* Contained SCLP equipment check */
 178                 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
 179                         break;
 180                 /* Remove processed buffers and requeue rest */
 181                 if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
 182                         /* Not all buffers were processed */
 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                 }
 188                 break;
 189
 190         case 0x0040: /* SCLP equipment check */
 191                 if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY)
 192                         break;
 193                 sccb->header.response_code = 0x0000;
 194                 vt220_request->sclp_req.status = SCLP_REQ_FILLED;
 195                 if (sclp_add_request(request) == 0)
 196                         return;
 197                 break;
 198
 199         default:
 200                 break;
 201         }
 202         sclp_vt220_process_queue(vt220_request);
 203 }
 204
 205 /*
 206  * Emit vt220 request buffer to SCLP. Return zero on success, non-zero
 207  * otherwise.
 208  */
 209 static int
 210 __sclp_vt220_emit(struct sclp_vt220_request *request)
 211 {
 212         if (!(sclp_vt220_register.sclp_receive_mask & EVTYP_VT220MSG_MASK)) {
 213                 request->sclp_req.status = SCLP_REQ_FAILED;
 214                 return -EIO;
 215         }
 216         request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
 217         request->sclp_req.status = SCLP_REQ_FILLED;
 218         request->sclp_req.callback = sclp_vt220_callback;
 219         request->sclp_req.callback_data = (void *) request;
 220
 221         return sclp_add_request(&request->sclp_req);
 222 }
 223
 224 /*
 225  * Queue and emit current request.
 226  */
 227 static void
 228 sclp_vt220_emit_current(void)
 229 {
 230         unsigned long flags;
 231         struct sclp_vt220_request *request;
 232         struct sclp_vt220_sccb *sccb;
 233
 234         spin_lock_irqsave(&sclp_vt220_lock, flags);
 235         if (sclp_vt220_current_request) {
 236                 sccb = (struct sclp_vt220_sccb *)
 237                                 sclp_vt220_current_request->sclp_req.sccb;
 238                 /* Only emit buffers with content */
 239                 if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
 240                         list_add_tail(&sclp_vt220_current_request->list,
 241                                       &sclp_vt220_outqueue);
 242                         sclp_vt220_current_request = NULL;
 243                         if (timer_pending(&sclp_vt220_timer))
 244                                 del_timer(&sclp_vt220_timer);
 245                 }
 246                 sclp_vt220_flush_later = 0;
 247         }
 248         if (sclp_vt220_queue_running || sclp_vt220_suspended)
 249                 goto out_unlock;
 250         if (list_empty(&sclp_vt220_outqueue))
 251                 goto out_unlock;
 252         request = list_first_entry(&sclp_vt220_outqueue,
 253                                    struct sclp_vt220_request, list);
 254         sclp_vt220_queue_running = 1;
 255         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 256
 257         if (__sclp_vt220_emit(request))
 258                 sclp_vt220_process_queue(request);
 259         return;
 260 out_unlock:
 261         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 262 }
 263
 264 #define SCLP_NORMAL_WRITE       0x00
 265
 266 /*
 267  * Helper function to initialize a page with the sclp request structure.
 268  */
 269 static struct sclp_vt220_request *
 270 sclp_vt220_initialize_page(void *page)
 271 {
 272         struct sclp_vt220_request *request;
 273         struct sclp_vt220_sccb *sccb;
 274
 275         /* Place request structure at end of page */
 276         request = ((struct sclp_vt220_request *)
 277                         ((addr_t) page + PAGE_SIZE)) - 1;
 278         request->retry_count = 0;
 279         request->sclp_req.sccb = page;
 280         /* SCCB goes at start of page */
 281         sccb = (struct sclp_vt220_sccb *) page;
 282         memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
 283         sccb->header.length = sizeof(struct sclp_vt220_sccb);
 284         sccb->header.function_code = SCLP_NORMAL_WRITE;
 285         sccb->header.response_code = 0x0000;
 286         sccb->evbuf.type = EVTYP_VT220MSG;
 287         sccb->evbuf.length = sizeof(struct evbuf_header);
 288
 289         return request;
 290 }
 291
 292 static inline unsigned int
 293 sclp_vt220_space_left(struct sclp_vt220_request *request)
 294 {
 295         struct sclp_vt220_sccb *sccb;
 296         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 297         return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
 298                sccb->header.length;
 299 }
 300
 301 static inline unsigned int
 302 sclp_vt220_chars_stored(struct sclp_vt220_request *request)
 303 {
 304         struct sclp_vt220_sccb *sccb;
 305         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 306         return sccb->evbuf.length - sizeof(struct evbuf_header);
 307 }
 308
 309 /*
 310  * Add msg to buffer associated with request. Return the number of characters
 311  * added.
 312  */
 313 static int
 314 sclp_vt220_add_msg(struct sclp_vt220_request *request,
 315                    const unsigned char *msg, int count, int convertlf)
 316 {
 317         struct sclp_vt220_sccb *sccb;
 318         void *buffer;
 319         unsigned char c;
 320         int from;
 321         int to;
 322
 323         if (count > sclp_vt220_space_left(request))
 324                 count = sclp_vt220_space_left(request);
 325         if (count <= 0)
 326                 return 0;
 327
 328         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 329         buffer = (void *) ((addr_t) sccb + sccb->header.length);
 330
 331         if (convertlf) {
 332                 /* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
 333                 for (from=0, to=0;
 334                      (from < count) && (to < sclp_vt220_space_left(request));
 335                      from++) {
 336                         /* Retrieve character */
 337                         c = msg[from];
 338                         /* Perform conversion */
 339                         if (c == 0x0a) {
 340                                 if (to + 1 < sclp_vt220_space_left(request)) {
 341                                         ((unsigned char *) buffer)[to++] = c;
 342                                         ((unsigned char *) buffer)[to++] = 0x0d;
 343                                 } else
 344                                         break;
 345
 346                         } else
 347                                 ((unsigned char *) buffer)[to++] = c;
 348                 }
 349                 sccb->header.length += to;
 350                 sccb->evbuf.length += to;
 351                 return from;
 352         } else {
 353                 memcpy(buffer, (const void *) msg, count);
 354                 sccb->header.length += count;
 355                 sccb->evbuf.length += count;
 356                 return count;
 357         }
 358 }
 359
 360 /*
 361  * Emit buffer after having waited long enough for more data to arrive.
 362  */
 363 static void
 364 sclp_vt220_timeout(unsigned long data)
 365 {
 366         sclp_vt220_emit_current();
 367 }
 368
 369 #define BUFFER_MAX_DELAY        HZ/20
 370
 371 /*
 372  * Internal implementation of the write function. Write COUNT bytes of data
 373  * from memory at BUF
 374  * to the SCLP interface. In case that the data does not fit into the current
 375  * write buffer, emit the current one and allocate a new one. If there are no
 376  * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
 377  * is non-zero, the buffer will be scheduled for emitting after a timeout -
 378  * otherwise the user has to explicitly call the flush function.
 379  * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
 380  * buffer should be converted to 0x0a 0x0d. After completion, return the number
 381  * of bytes written.
 382  */
 383 static int
 384 __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
 385                    int convertlf, int may_fail)
 386 {
 387         unsigned long flags;
 388         void *page;
 389         int written;
 390         int overall_written;
 391
 392         if (count <= 0)
 393                 return 0;
 394         overall_written = 0;
 395         spin_lock_irqsave(&sclp_vt220_lock, flags);
 396         do {
 397                 /* Create an sclp output buffer if none exists yet */
 398                 if (sclp_vt220_current_request == NULL) {
 399                         while (list_empty(&sclp_vt220_empty)) {
 400                                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 401                                 if (may_fail || sclp_vt220_suspended)
 402                                         goto out;
 403                                 else
 404                                         sclp_sync_wait();
 405                                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 406                         }
 407                         page = (void *) sclp_vt220_empty.next;
 408                         list_del((struct list_head *) page);
 409                         sclp_vt220_current_request =
 410                                 sclp_vt220_initialize_page(page);
 411                 }
 412                 /* Try to write the string to the current request buffer */
 413                 written = sclp_vt220_add_msg(sclp_vt220_current_request,
 414                                              buf, count, convertlf);
 415                 overall_written += written;
 416                 if (written == count)
 417                         break;
 418                 /*
 419                  * Not all characters could be written to the current
 420                  * output buffer. Emit the buffer, create a new buffer
 421                  * and then output the rest of the string.
 422                  */
 423                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 424                 sclp_vt220_emit_current();
 425                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 426                 buf += written;
 427                 count -= written;
 428         } while (count > 0);
 429         /* Setup timer to output current console buffer after some time */
 430         if (sclp_vt220_current_request != NULL &&
 431             !timer_pending(&sclp_vt220_timer) && do_schedule) {
 432                 sclp_vt220_timer.function = sclp_vt220_timeout;
 433                 sclp_vt220_timer.data = 0UL;
 434                 sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
 435                 add_timer(&sclp_vt220_timer);
 436         }
 437         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 438 out:
 439         return overall_written;
 440 }
 441
 442 /*
 443  * This routine is called by the kernel to write a series of
 444  * characters to the tty device.  The characters may come from
 445  * user space or kernel space.  This routine will return the
 446  * number of characters actually accepted for writing.
 447  */
 448 static int
 449 sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
 450 {
 451         return __sclp_vt220_write(buf, count, 1, 0, 1);
 452 }
 453
 454 #define SCLP_VT220_SESSION_ENDED        0x01
 455 #define SCLP_VT220_SESSION_STARTED      0x80
 456 #define SCLP_VT220_SESSION_DATA         0x00
 457
 458 /*
 459  * Called by the SCLP to report incoming event buffers.
 460  */
 461 static void
 462 sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
 463 {
 464         struct tty_struct *tty = tty_port_tty_get(&sclp_vt220_port);
 465         char *buffer;
 466         unsigned int count;
 467
 468         /* Ignore input if device is not open */
 469         if (tty == NULL)
 470                 return;
 471
 472         buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
 473         count = evbuf->length - sizeof(struct evbuf_header);
 474
 475         switch (*buffer) {
 476         case SCLP_VT220_SESSION_ENDED:
 477         case SCLP_VT220_SESSION_STARTED:
 478                 break;
 479         case SCLP_VT220_SESSION_DATA:
 480                 /* Send input to line discipline */
 481                 buffer++;
 482                 count--;
 483                 tty_insert_flip_string(tty, buffer, count);
 484                 tty_flip_buffer_push(tty);
 485                 break;
 486         }
 487         tty_kref_put(tty);
 488 }
 489
 490 /*
 491  * This routine is called when a particular tty device is opened.
 492  */
 493 static int
 494 sclp_vt220_open(struct tty_struct *tty, struct file *filp)
 495 {
 496         if (tty->count == 1) {
 497                 tty_port_tty_set(&sclp_vt220_port, tty);
 498                 tty->low_latency = 0;
 499                 if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
 500                         tty->winsize.ws_row = 24;
 501                         tty->winsize.ws_col = 80;
 502                 }
 503         }
 504         return 0;
 505 }
 506
 507 /*
 508  * This routine is called when a particular tty device is closed.
 509  */
 510 static void
 511 sclp_vt220_close(struct tty_struct *tty, struct file *filp)
 512 {
 513         if (tty->count == 1)
 514                 tty_port_tty_set(&sclp_vt220_port, NULL);
 515 }
 516
 517 /*
 518  * This routine is called by the kernel to write a single
 519  * character to the tty device.  If the kernel uses this routine,
 520  * it must call the flush_chars() routine (if defined) when it is
 521  * done stuffing characters into the driver.
 522  */
 523 static int
 524 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
 525 {
 526         return __sclp_vt220_write(&ch, 1, 0, 0, 1);
 527 }
 528
 529 /*
 530  * This routine is called by the kernel after it has written a
 531  * series of characters to the tty device using put_char().
 532  */
 533 static void
 534 sclp_vt220_flush_chars(struct tty_struct *tty)
 535 {
 536         if (!sclp_vt220_queue_running)
 537                 sclp_vt220_emit_current();
 538         else
 539                 sclp_vt220_flush_later = 1;
 540 }
 541
 542 /*
 543  * This routine returns the numbers of characters the tty driver
 544  * will accept for queuing to be written.  This number is subject
 545  * to change as output buffers get emptied, or if the output flow
 546  * control is acted.
 547  */
 548 static int
 549 sclp_vt220_write_room(struct tty_struct *tty)
 550 {
 551         unsigned long flags;
 552         struct list_head *l;
 553         int count;
 554
 555         spin_lock_irqsave(&sclp_vt220_lock, flags);
 556         count = 0;
 557         if (sclp_vt220_current_request != NULL)
 558                 count = sclp_vt220_space_left(sclp_vt220_current_request);
 559         list_for_each(l, &sclp_vt220_empty)
 560                 count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
 561         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 562         return count;
 563 }
 564
 565 /*
 566  * Return number of buffered chars.
 567  */
 568 static int
 569 sclp_vt220_chars_in_buffer(struct tty_struct *tty)
 570 {
 571         unsigned long flags;
 572         struct list_head *l;
 573         struct sclp_vt220_request *r;
 574         int count;
 575
 576         spin_lock_irqsave(&sclp_vt220_lock, flags);
 577         count = 0;
 578         if (sclp_vt220_current_request != NULL)
 579                 count = sclp_vt220_chars_stored(sclp_vt220_current_request);
 580         list_for_each(l, &sclp_vt220_outqueue) {
 581                 r = list_entry(l, struct sclp_vt220_request, list);
 582                 count += sclp_vt220_chars_stored(r);
 583         }
 584         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 585         return count;
 586 }
 587
 588 /*
 589  * Pass on all buffers to the hardware. Return only when there are no more
 590  * buffers pending.
 591  */
 592 static void
 593 sclp_vt220_flush_buffer(struct tty_struct *tty)
 594 {
 595         sclp_vt220_emit_current();
 596 }
 597
 598 /* Release allocated pages. */
 599 static void __init __sclp_vt220_free_pages(void)
 600 {
 601         struct list_head *page, *p;
 602
 603         list_for_each_safe(page, p, &sclp_vt220_empty) {
 604                 list_del(page);
 605                 free_page((unsigned long) page);
 606         }
 607 }
 608
 609 /* Release memory and unregister from sclp core. Controlled by init counting -
 610  * only the last invoker will actually perform these actions. */
 611 static void __init __sclp_vt220_cleanup(void)
 612 {
 613         sclp_vt220_init_count--;
 614         if (sclp_vt220_init_count != 0)
 615                 return;
 616         sclp_unregister(&sclp_vt220_register);
 617         __sclp_vt220_free_pages();
 618         tty_port_destroy(&sclp_vt220_port);
 619 }
 620
 621 /* Allocate buffer pages and register with sclp core. Controlled by init
 622  * counting - only the first invoker will actually perform these actions. */
 623 static int __init __sclp_vt220_init(int num_pages)
 624 {
 625         void *page;
 626         int i;
 627         int rc;
 628
 629         sclp_vt220_init_count++;
 630         if (sclp_vt220_init_count != 1)
 631                 return 0;
 632         spin_lock_init(&sclp_vt220_lock);
 633         INIT_LIST_HEAD(&sclp_vt220_empty);
 634         INIT_LIST_HEAD(&sclp_vt220_outqueue);
 635         init_timer(&sclp_vt220_timer);
 636         tty_port_init(&sclp_vt220_port);
 637         sclp_vt220_current_request = NULL;
 638         sclp_vt220_buffered_chars = 0;
 639         sclp_vt220_flush_later = 0;
 640
 641         /* Allocate pages for output buffering */
 642         rc = -ENOMEM;
 643         for (i = 0; i < num_pages; i++) {
 644                 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 645                 if (!page)
 646                         goto out;
 647                 list_add_tail(page, &sclp_vt220_empty);
 648         }
 649         rc = sclp_register(&sclp_vt220_register);
 650 out:
 651         if (rc) {
 652                 __sclp_vt220_free_pages();
 653                 sclp_vt220_init_count--;
 654                 tty_port_destroy(&sclp_vt220_port);
 655         }
 656         return rc;
 657 }
 658
 659 static const struct tty_operations sclp_vt220_ops = {
 660         .open = sclp_vt220_open,
 661         .close = sclp_vt220_close,
 662         .write = sclp_vt220_write,
 663         .put_char = sclp_vt220_put_char,
 664         .flush_chars = sclp_vt220_flush_chars,
 665         .write_room = sclp_vt220_write_room,
 666         .chars_in_buffer = sclp_vt220_chars_in_buffer,
 667         .flush_buffer = sclp_vt220_flush_buffer,
 668 };
 669
 670 /*
 671  * Register driver with SCLP and Linux and initialize internal tty structures.
 672  */
 673 static int __init sclp_vt220_tty_init(void)
 674 {
 675         struct tty_driver *driver;
 676         int rc;
 677
 678         /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
 679          * symmetry between VM and LPAR systems regarding ttyS1. */
 680         driver = alloc_tty_driver(1);
 681         if (!driver)
 682                 return -ENOMEM;
 683         rc = __sclp_vt220_init(MAX_KMEM_PAGES);
 684         if (rc)
 685                 goto out_driver;
 686
 687         driver->driver_name = SCLP_VT220_DRIVER_NAME;
 688         driver->name = SCLP_VT220_DEVICE_NAME;
 689         driver->major = SCLP_VT220_MAJOR;
 690         driver->minor_start = SCLP_VT220_MINOR;
 691         driver->type = TTY_DRIVER_TYPE_SYSTEM;
 692         driver->subtype = SYSTEM_TYPE_TTY;
 693         driver->init_termios = tty_std_termios;
 694         driver->flags = TTY_DRIVER_REAL_RAW;
 695         tty_set_operations(driver, &sclp_vt220_ops);
 696         tty_port_link_device(&sclp_vt220_port, driver, 0);
 697
 698         rc = tty_register_driver(driver);
 699         if (rc)
 700                 goto out_init;
 701         sclp_vt220_driver = driver;
 702         return 0;
 703
 704 out_init:
 705         __sclp_vt220_cleanup();
 706 out_driver:
 707         put_tty_driver(driver);
 708         return rc;
 709 }
 710 __initcall(sclp_vt220_tty_init);
 711
 712 static void __sclp_vt220_flush_buffer(void)
 713 {
 714         unsigned long flags;
 715
 716         sclp_vt220_emit_current();
 717         spin_lock_irqsave(&sclp_vt220_lock, flags);
 718         if (timer_pending(&sclp_vt220_timer))
 719                 del_timer(&sclp_vt220_timer);
 720         while (sclp_vt220_queue_running) {
 721                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 722                 sclp_sync_wait();
 723                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 724         }
 725         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 726 }
 727
 728 /*
 729  * Resume console: If there are cached messages, emit them.
 730  */
 731 static void sclp_vt220_resume(void)
 732 {
 733         unsigned long flags;
 734
 735         spin_lock_irqsave(&sclp_vt220_lock, flags);
 736         sclp_vt220_suspended = 0;
 737         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 738         sclp_vt220_emit_current();
 739 }
 740
 741 /*
 742  * Suspend console: Set suspend flag and flush console
 743  */
 744 static void sclp_vt220_suspend(void)
 745 {
 746         unsigned long flags;
 747
 748         spin_lock_irqsave(&sclp_vt220_lock, flags);
 749         sclp_vt220_suspended = 1;
 750         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 751         __sclp_vt220_flush_buffer();
 752 }
 753
 754 static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
 755                                    enum sclp_pm_event sclp_pm_event)
 756 {
 757         switch (sclp_pm_event) {
 758         case SCLP_PM_EVENT_FREEZE:
 759                 sclp_vt220_suspend();
 760                 break;
 761         case SCLP_PM_EVENT_RESTORE:
 762         case SCLP_PM_EVENT_THAW:
 763                 sclp_vt220_resume();
 764                 break;
 765         }
 766 }
 767
 768 #ifdef CONFIG_SCLP_VT220_CONSOLE
 769
 770 static void
 771 sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
 772 {
 773         __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
 774 }
 775
 776 static struct tty_driver *
 777 sclp_vt220_con_device(struct console *c, int *index)
 778 {
 779         *index = 0;
 780         return sclp_vt220_driver;
 781 }
 782
 783 static int
 784 sclp_vt220_notify(struct notifier_block *self,
 785                           unsigned long event, void *data)
 786 {
 787         __sclp_vt220_flush_buffer();
 788         return NOTIFY_OK;
 789 }
 790
 791 static struct notifier_block on_panic_nb = {
 792         .notifier_call = sclp_vt220_notify,
 793         .priority = 1,
 794 };
 795
 796 static struct notifier_block on_reboot_nb = {
 797         .notifier_call = sclp_vt220_notify,
 798         .priority = 1,
 799 };
 800
 801 /* Structure needed to register with printk */
 802 static struct console sclp_vt220_console =
 803 {
 804         .name = SCLP_VT220_CONSOLE_NAME,
 805         .write = sclp_vt220_con_write,
 806         .device = sclp_vt220_con_device,
 807         .flags = CON_PRINTBUFFER,
 808         .index = SCLP_VT220_CONSOLE_INDEX
 809 };
 810
 811 static int __init
 812 sclp_vt220_con_init(void)
 813 {
 814         int rc;
 815
 816         if (!CONSOLE_IS_SCLP)
 817                 return 0;
 818         rc = __sclp_vt220_init(MAX_CONSOLE_PAGES);
 819         if (rc)
 820                 return rc;
 821         /* Attach linux console */
 822         atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
 823         register_reboot_notifier(&on_reboot_nb);
 824         register_console(&sclp_vt220_console);
 825         return 0;
 826 }
 827
 828 console_initcall(sclp_vt220_con_init);
 829 #endif /* CONFIG_SCLP_VT220_CONSOLE */
 830