drivers/s390/char/sclp_vt220.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SCLP VT220 terminal driver.
   4  *
   5  * Copyright IBM Corp. 2003, 2009
   6  *
   7  * Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/list.h>
  13 #include <linux/wait.h>
  14 #include <linux/timer.h>
  15 #include <linux/kernel.h>
  16 #include <linux/sysrq.h>
  17 #include <linux/tty.h>
  18 #include <linux/tty_driver.h>
  19 #include <linux/tty_flip.h>
  20 #include <linux/errno.h>
  21 #include <linux/mm.h>
  22 #include <linux/major.h>
  23 #include <linux/console.h>
  24 #include <linux/kdev_t.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/init.h>
  27 #include <linux/reboot.h>
  28 #include <linux/slab.h>
  29
  30 #include <linux/uaccess.h>
  31 #include "sclp.h"
  32 #include "ctrlchar.h"
  33
  34 #define SCLP_VT220_MAJOR                TTY_MAJOR
  35 #define SCLP_VT220_MINOR                65
  36 #define SCLP_VT220_DRIVER_NAME          "sclp_vt220"
  37 #define SCLP_VT220_DEVICE_NAME          "ttysclp"
  38 #define SCLP_VT220_CONSOLE_NAME         "ttyS"
  39 #define SCLP_VT220_CONSOLE_INDEX        1       /* console=ttyS1 */
  40
  41 /* Representation of a single write request */
  42 struct sclp_vt220_request {
  43         struct list_head list;
  44         struct sclp_req sclp_req;
  45         int retry_count;
  46 };
  47
  48 /* VT220 SCCB */
  49 struct sclp_vt220_sccb {
  50         struct sccb_header header;
  51         struct evbuf_header evbuf;
  52 };
  53
  54 #define SCLP_VT220_MAX_CHARS_PER_BUFFER (PAGE_SIZE - \
  55                                          sizeof(struct sclp_vt220_request) - \
  56                                          sizeof(struct sclp_vt220_sccb))
  57
  58 /* Structures and data needed to register tty driver */
  59 static struct tty_driver *sclp_vt220_driver;
  60
  61 static struct tty_port sclp_vt220_port;
  62
  63 /* Lock to protect internal data from concurrent access */
  64 static DEFINE_SPINLOCK(sclp_vt220_lock);
  65
  66 /* List of empty pages to be used as write request buffers */
  67 static LIST_HEAD(sclp_vt220_empty);
  68
  69 /* List of pending requests */
  70 static LIST_HEAD(sclp_vt220_outqueue);
  71
  72 /* Suspend mode flag */
  73 static int sclp_vt220_suspended;
  74
  75 /* Flag that output queue is currently running */
  76 static int sclp_vt220_queue_running;
  77
  78 /* Timer used for delaying write requests to merge subsequent messages into
  79  * a single buffer */
  80 static struct timer_list sclp_vt220_timer;
  81
  82 /* Pointer to current request buffer which has been partially filled but not
  83  * yet sent */
  84 static struct sclp_vt220_request *sclp_vt220_current_request;
  85
  86 /* Number of characters in current request buffer */
  87 static int sclp_vt220_buffered_chars;
  88
  89 /* Counter controlling core driver initialization. */
  90 static int __initdata sclp_vt220_init_count;
  91
  92 /* Flag indicating that sclp_vt220_current_request should really
  93  * have been already queued but wasn't because the SCLP was processing
  94  * another buffer */
  95 static int sclp_vt220_flush_later;
  96
  97 static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
  98 static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
  99                                    enum sclp_pm_event sclp_pm_event);
 100 static int __sclp_vt220_emit(struct sclp_vt220_request *request);
 101 static void sclp_vt220_emit_current(void);
 102
 103 /* Registration structure for SCLP output event buffers */
 104 static struct sclp_register sclp_vt220_register = {
 105         .send_mask              = EVTYP_VT220MSG_MASK,
 106         .pm_event_fn            = sclp_vt220_pm_event_fn,
 107 };
 108
 109 /* Registration structure for SCLP input event buffers */
 110 static struct sclp_register sclp_vt220_register_input = {
 111         .receive_mask           = EVTYP_VT220MSG_MASK,
 112         .receiver_fn            = sclp_vt220_receiver_fn,
 113 };
 114
 115
 116 /*
 117  * Put provided request buffer back into queue and check emit pending
 118  * buffers if necessary.
 119  */
 120 static void
 121 sclp_vt220_process_queue(struct sclp_vt220_request *request)
 122 {
 123         unsigned long flags;
 124         void *page;
 125
 126         do {
 127                 /* Put buffer back to list of empty buffers */
 128                 page = request->sclp_req.sccb;
 129                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 130                 /* Move request from outqueue to empty queue */
 131                 list_del(&request->list);
 132                 list_add_tail((struct list_head *) page, &sclp_vt220_empty);
 133                 /* Check if there is a pending buffer on the out queue. */
 134                 request = NULL;
 135                 if (!list_empty(&sclp_vt220_outqueue))
 136                         request = list_entry(sclp_vt220_outqueue.next,
 137                                              struct sclp_vt220_request, list);
 138                 if (!request || sclp_vt220_suspended) {
 139                         sclp_vt220_queue_running = 0;
 140                         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 141                         break;
 142                 }
 143                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 144         } while (__sclp_vt220_emit(request));
 145         if (request == NULL && sclp_vt220_flush_later)
 146                 sclp_vt220_emit_current();
 147         tty_port_tty_wakeup(&sclp_vt220_port);
 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         request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
 213         request->sclp_req.status = SCLP_REQ_FILLED;
 214         request->sclp_req.callback = sclp_vt220_callback;
 215         request->sclp_req.callback_data = (void *) request;
 216
 217         return sclp_add_request(&request->sclp_req);
 218 }
 219
 220 /*
 221  * Queue and emit current request.
 222  */
 223 static void
 224 sclp_vt220_emit_current(void)
 225 {
 226         unsigned long flags;
 227         struct sclp_vt220_request *request;
 228         struct sclp_vt220_sccb *sccb;
 229
 230         spin_lock_irqsave(&sclp_vt220_lock, flags);
 231         if (sclp_vt220_current_request) {
 232                 sccb = (struct sclp_vt220_sccb *)
 233                                 sclp_vt220_current_request->sclp_req.sccb;
 234                 /* Only emit buffers with content */
 235                 if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) {
 236                         list_add_tail(&sclp_vt220_current_request->list,
 237                                       &sclp_vt220_outqueue);
 238                         sclp_vt220_current_request = NULL;
 239                         if (timer_pending(&sclp_vt220_timer))
 240                                 del_timer(&sclp_vt220_timer);
 241                 }
 242                 sclp_vt220_flush_later = 0;
 243         }
 244         if (sclp_vt220_queue_running || sclp_vt220_suspended)
 245                 goto out_unlock;
 246         if (list_empty(&sclp_vt220_outqueue))
 247                 goto out_unlock;
 248         request = list_first_entry(&sclp_vt220_outqueue,
 249                                    struct sclp_vt220_request, list);
 250         sclp_vt220_queue_running = 1;
 251         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 252
 253         if (__sclp_vt220_emit(request))
 254                 sclp_vt220_process_queue(request);
 255         return;
 256 out_unlock:
 257         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 258 }
 259
 260 #define SCLP_NORMAL_WRITE       0x00
 261
 262 /*
 263  * Helper function to initialize a page with the sclp request structure.
 264  */
 265 static struct sclp_vt220_request *
 266 sclp_vt220_initialize_page(void *page)
 267 {
 268         struct sclp_vt220_request *request;
 269         struct sclp_vt220_sccb *sccb;
 270
 271         /* Place request structure at end of page */
 272         request = ((struct sclp_vt220_request *)
 273                         ((addr_t) page + PAGE_SIZE)) - 1;
 274         request->retry_count = 0;
 275         request->sclp_req.sccb = page;
 276         /* SCCB goes at start of page */
 277         sccb = (struct sclp_vt220_sccb *) page;
 278         memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb));
 279         sccb->header.length = sizeof(struct sclp_vt220_sccb);
 280         sccb->header.function_code = SCLP_NORMAL_WRITE;
 281         sccb->header.response_code = 0x0000;
 282         sccb->evbuf.type = EVTYP_VT220MSG;
 283         sccb->evbuf.length = sizeof(struct evbuf_header);
 284
 285         return request;
 286 }
 287
 288 static inline unsigned int
 289 sclp_vt220_space_left(struct sclp_vt220_request *request)
 290 {
 291         struct sclp_vt220_sccb *sccb;
 292         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 293         return PAGE_SIZE - sizeof(struct sclp_vt220_request) -
 294                sccb->header.length;
 295 }
 296
 297 static inline unsigned int
 298 sclp_vt220_chars_stored(struct sclp_vt220_request *request)
 299 {
 300         struct sclp_vt220_sccb *sccb;
 301         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 302         return sccb->evbuf.length - sizeof(struct evbuf_header);
 303 }
 304
 305 /*
 306  * Add msg to buffer associated with request. Return the number of characters
 307  * added.
 308  */
 309 static int
 310 sclp_vt220_add_msg(struct sclp_vt220_request *request,
 311                    const unsigned char *msg, int count, int convertlf)
 312 {
 313         struct sclp_vt220_sccb *sccb;
 314         void *buffer;
 315         unsigned char c;
 316         int from;
 317         int to;
 318
 319         if (count > sclp_vt220_space_left(request))
 320                 count = sclp_vt220_space_left(request);
 321         if (count <= 0)
 322                 return 0;
 323
 324         sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb;
 325         buffer = (void *) ((addr_t) sccb + sccb->header.length);
 326
 327         if (convertlf) {
 328                 /* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
 329                 for (from=0, to=0;
 330                      (from < count) && (to < sclp_vt220_space_left(request));
 331                      from++) {
 332                         /* Retrieve character */
 333                         c = msg[from];
 334                         /* Perform conversion */
 335                         if (c == 0x0a) {
 336                                 if (to + 1 < sclp_vt220_space_left(request)) {
 337                                         ((unsigned char *) buffer)[to++] = c;
 338                                         ((unsigned char *) buffer)[to++] = 0x0d;
 339                                 } else
 340                                         break;
 341
 342                         } else
 343                                 ((unsigned char *) buffer)[to++] = c;
 344                 }
 345                 sccb->header.length += to;
 346                 sccb->evbuf.length += to;
 347                 return from;
 348         } else {
 349                 memcpy(buffer, (const void *) msg, count);
 350                 sccb->header.length += count;
 351                 sccb->evbuf.length += count;
 352                 return count;
 353         }
 354 }
 355
 356 /*
 357  * Emit buffer after having waited long enough for more data to arrive.
 358  */
 359 static void
 360 sclp_vt220_timeout(struct timer_list *unused)
 361 {
 362         sclp_vt220_emit_current();
 363 }
 364
 365 #define BUFFER_MAX_DELAY        HZ/20
 366
 367 /*
 368  * Drop oldest console buffer if sclp_con_drop is set
 369  */
 370 static int
 371 sclp_vt220_drop_buffer(void)
 372 {
 373         struct list_head *list;
 374         struct sclp_vt220_request *request;
 375         void *page;
 376
 377         if (!sclp_console_drop)
 378                 return 0;
 379         list = sclp_vt220_outqueue.next;
 380         if (sclp_vt220_queue_running)
 381                 /* The first element is in I/O */
 382                 list = list->next;
 383         if (list == &sclp_vt220_outqueue)
 384                 return 0;
 385         list_del(list);
 386         request = list_entry(list, struct sclp_vt220_request, list);
 387         page = request->sclp_req.sccb;
 388         list_add_tail((struct list_head *) page, &sclp_vt220_empty);
 389         return 1;
 390 }
 391
 392 /*
 393  * Internal implementation of the write function. Write COUNT bytes of data
 394  * from memory at BUF
 395  * to the SCLP interface. In case that the data does not fit into the current
 396  * write buffer, emit the current one and allocate a new one. If there are no
 397  * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE
 398  * is non-zero, the buffer will be scheduled for emitting after a timeout -
 399  * otherwise the user has to explicitly call the flush function.
 400  * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message
 401  * buffer should be converted to 0x0a 0x0d. After completion, return the number
 402  * of bytes written.
 403  */
 404 static int
 405 __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
 406                    int convertlf, int may_fail)
 407 {
 408         unsigned long flags;
 409         void *page;
 410         int written;
 411         int overall_written;
 412
 413         if (count <= 0)
 414                 return 0;
 415         overall_written = 0;
 416         spin_lock_irqsave(&sclp_vt220_lock, flags);
 417         do {
 418                 /* Create an sclp output buffer if none exists yet */
 419                 if (sclp_vt220_current_request == NULL) {
 420                         if (list_empty(&sclp_vt220_empty))
 421                                 sclp_console_full++;
 422                         while (list_empty(&sclp_vt220_empty)) {
 423                                 if (may_fail || sclp_vt220_suspended)
 424                                         goto out;
 425                                 if (sclp_vt220_drop_buffer())
 426                                         break;
 427                                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 428
 429                                 sclp_sync_wait();
 430                                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 431                         }
 432                         page = (void *) sclp_vt220_empty.next;
 433                         list_del((struct list_head *) page);
 434                         sclp_vt220_current_request =
 435                                 sclp_vt220_initialize_page(page);
 436                 }
 437                 /* Try to write the string to the current request buffer */
 438                 written = sclp_vt220_add_msg(sclp_vt220_current_request,
 439                                              buf, count, convertlf);
 440                 overall_written += written;
 441                 if (written == count)
 442                         break;
 443                 /*
 444                  * Not all characters could be written to the current
 445                  * output buffer. Emit the buffer, create a new buffer
 446                  * and then output the rest of the string.
 447                  */
 448                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 449                 sclp_vt220_emit_current();
 450                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 451                 buf += written;
 452                 count -= written;
 453         } while (count > 0);
 454         /* Setup timer to output current console buffer after some time */
 455         if (sclp_vt220_current_request != NULL &&
 456             !timer_pending(&sclp_vt220_timer) && do_schedule) {
 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 #ifdef CONFIG_MAGIC_SYSRQ
 482
 483 static int sysrq_pressed;
 484 static struct sysrq_work sysrq;
 485
 486 static void sclp_vt220_reset_session(void)
 487 {
 488         sysrq_pressed = 0;
 489 }
 490
 491 static void sclp_vt220_handle_input(const char *buffer, unsigned int count)
 492 {
 493         int i;
 494
 495         for (i = 0; i < count; i++) {
 496                 /* Handle magic sys request */
 497                 if (buffer[i] == ('O' ^ 0100)) { /* CTRL-O */
 498                         /*
 499                          * If pressed again, reset sysrq_pressed
 500                          * and flip CTRL-O character
 501                          */
 502                         sysrq_pressed = !sysrq_pressed;
 503                         if (sysrq_pressed)
 504                                 continue;
 505                 } else if (sysrq_pressed) {
 506                         sysrq.key = buffer[i];
 507                         schedule_sysrq_work(&sysrq);
 508                         sysrq_pressed = 0;
 509                         continue;
 510                 }
 511                 tty_insert_flip_char(&sclp_vt220_port, buffer[i], 0);
 512         }
 513 }
 514
 515 #else
 516
 517 static void sclp_vt220_reset_session(void)
 518 {
 519 }
 520
 521 static void sclp_vt220_handle_input(const char *buffer, unsigned int count)
 522 {
 523         tty_insert_flip_string(&sclp_vt220_port, buffer, count);
 524 }
 525
 526 #endif
 527
 528 /*
 529  * Called by the SCLP to report incoming event buffers.
 530  */
 531 static void
 532 sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
 533 {
 534         char *buffer;
 535         unsigned int count;
 536
 537         buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
 538         count = evbuf->length - sizeof(struct evbuf_header);
 539
 540         switch (*buffer) {
 541         case SCLP_VT220_SESSION_ENDED:
 542         case SCLP_VT220_SESSION_STARTED:
 543                 sclp_vt220_reset_session();
 544                 break;
 545         case SCLP_VT220_SESSION_DATA:
 546                 /* Send input to line discipline */
 547                 buffer++;
 548                 count--;
 549                 sclp_vt220_handle_input(buffer, count);
 550                 tty_flip_buffer_push(&sclp_vt220_port);
 551                 break;
 552         }
 553 }
 554
 555 /*
 556  * This routine is called when a particular tty device is opened.
 557  */
 558 static int
 559 sclp_vt220_open(struct tty_struct *tty, struct file *filp)
 560 {
 561         if (tty->count == 1) {
 562                 tty_port_tty_set(&sclp_vt220_port, tty);
 563                 if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
 564                         tty->winsize.ws_row = 24;
 565                         tty->winsize.ws_col = 80;
 566                 }
 567         }
 568         return 0;
 569 }
 570
 571 /*
 572  * This routine is called when a particular tty device is closed.
 573  */
 574 static void
 575 sclp_vt220_close(struct tty_struct *tty, struct file *filp)
 576 {
 577         if (tty->count == 1)
 578                 tty_port_tty_set(&sclp_vt220_port, NULL);
 579 }
 580
 581 /*
 582  * This routine is called by the kernel to write a single
 583  * character to the tty device.  If the kernel uses this routine,
 584  * it must call the flush_chars() routine (if defined) when it is
 585  * done stuffing characters into the driver.
 586  */
 587 static int
 588 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
 589 {
 590         return __sclp_vt220_write(&ch, 1, 0, 0, 1);
 591 }
 592
 593 /*
 594  * This routine is called by the kernel after it has written a
 595  * series of characters to the tty device using put_char().
 596  */
 597 static void
 598 sclp_vt220_flush_chars(struct tty_struct *tty)
 599 {
 600         if (!sclp_vt220_queue_running)
 601                 sclp_vt220_emit_current();
 602         else
 603                 sclp_vt220_flush_later = 1;
 604 }
 605
 606 /*
 607  * This routine returns the numbers of characters the tty driver
 608  * will accept for queuing to be written.  This number is subject
 609  * to change as output buffers get emptied, or if the output flow
 610  * control is acted.
 611  */
 612 static int
 613 sclp_vt220_write_room(struct tty_struct *tty)
 614 {
 615         unsigned long flags;
 616         struct list_head *l;
 617         int count;
 618
 619         spin_lock_irqsave(&sclp_vt220_lock, flags);
 620         count = 0;
 621         if (sclp_vt220_current_request != NULL)
 622                 count = sclp_vt220_space_left(sclp_vt220_current_request);
 623         list_for_each(l, &sclp_vt220_empty)
 624                 count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
 625         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 626         return count;
 627 }
 628
 629 /*
 630  * Return number of buffered chars.
 631  */
 632 static int
 633 sclp_vt220_chars_in_buffer(struct tty_struct *tty)
 634 {
 635         unsigned long flags;
 636         struct list_head *l;
 637         struct sclp_vt220_request *r;
 638         int count;
 639
 640         spin_lock_irqsave(&sclp_vt220_lock, flags);
 641         count = 0;
 642         if (sclp_vt220_current_request != NULL)
 643                 count = sclp_vt220_chars_stored(sclp_vt220_current_request);
 644         list_for_each(l, &sclp_vt220_outqueue) {
 645                 r = list_entry(l, struct sclp_vt220_request, list);
 646                 count += sclp_vt220_chars_stored(r);
 647         }
 648         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 649         return count;
 650 }
 651
 652 /*
 653  * Pass on all buffers to the hardware. Return only when there are no more
 654  * buffers pending.
 655  */
 656 static void
 657 sclp_vt220_flush_buffer(struct tty_struct *tty)
 658 {
 659         sclp_vt220_emit_current();
 660 }
 661
 662 /* Release allocated pages. */
 663 static void __init __sclp_vt220_free_pages(void)
 664 {
 665         struct list_head *page, *p;
 666
 667         list_for_each_safe(page, p, &sclp_vt220_empty) {
 668                 list_del(page);
 669                 free_page((unsigned long) page);
 670         }
 671 }
 672
 673 /* Release memory and unregister from sclp core. Controlled by init counting -
 674  * only the last invoker will actually perform these actions. */
 675 static void __init __sclp_vt220_cleanup(void)
 676 {
 677         sclp_vt220_init_count--;
 678         if (sclp_vt220_init_count != 0)
 679                 return;
 680         sclp_unregister(&sclp_vt220_register);
 681         __sclp_vt220_free_pages();
 682         tty_port_destroy(&sclp_vt220_port);
 683 }
 684
 685 /* Allocate buffer pages and register with sclp core. Controlled by init
 686  * counting - only the first invoker will actually perform these actions. */
 687 static int __init __sclp_vt220_init(int num_pages)
 688 {
 689         void *page;
 690         int i;
 691         int rc;
 692
 693         sclp_vt220_init_count++;
 694         if (sclp_vt220_init_count != 1)
 695                 return 0;
 696         timer_setup(&sclp_vt220_timer, sclp_vt220_timeout, 0);
 697         tty_port_init(&sclp_vt220_port);
 698         sclp_vt220_current_request = NULL;
 699         sclp_vt220_buffered_chars = 0;
 700         sclp_vt220_flush_later = 0;
 701
 702         /* Allocate pages for output buffering */
 703         rc = -ENOMEM;
 704         for (i = 0; i < num_pages; i++) {
 705                 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 706                 if (!page)
 707                         goto out;
 708                 list_add_tail(page, &sclp_vt220_empty);
 709         }
 710         rc = sclp_register(&sclp_vt220_register);
 711 out:
 712         if (rc) {
 713                 __sclp_vt220_free_pages();
 714                 sclp_vt220_init_count--;
 715                 tty_port_destroy(&sclp_vt220_port);
 716         }
 717         return rc;
 718 }
 719
 720 static const struct tty_operations sclp_vt220_ops = {
 721         .open = sclp_vt220_open,
 722         .close = sclp_vt220_close,
 723         .write = sclp_vt220_write,
 724         .put_char = sclp_vt220_put_char,
 725         .flush_chars = sclp_vt220_flush_chars,
 726         .write_room = sclp_vt220_write_room,
 727         .chars_in_buffer = sclp_vt220_chars_in_buffer,
 728         .flush_buffer = sclp_vt220_flush_buffer,
 729 };
 730
 731 /*
 732  * Register driver with SCLP and Linux and initialize internal tty structures.
 733  */
 734 static int __init sclp_vt220_tty_init(void)
 735 {
 736         struct tty_driver *driver;
 737         int rc;
 738
 739         /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
 740          * symmetry between VM and LPAR systems regarding ttyS1. */
 741         driver = alloc_tty_driver(1);
 742         if (!driver)
 743                 return -ENOMEM;
 744         rc = __sclp_vt220_init(MAX_KMEM_PAGES);
 745         if (rc)
 746                 goto out_driver;
 747
 748         driver->driver_name = SCLP_VT220_DRIVER_NAME;
 749         driver->name = SCLP_VT220_DEVICE_NAME;
 750         driver->major = SCLP_VT220_MAJOR;
 751         driver->minor_start = SCLP_VT220_MINOR;
 752         driver->type = TTY_DRIVER_TYPE_SYSTEM;
 753         driver->subtype = SYSTEM_TYPE_TTY;
 754         driver->init_termios = tty_std_termios;
 755         driver->flags = TTY_DRIVER_REAL_RAW;
 756         tty_set_operations(driver, &sclp_vt220_ops);
 757         tty_port_link_device(&sclp_vt220_port, driver, 0);
 758
 759         rc = tty_register_driver(driver);
 760         if (rc)
 761                 goto out_init;
 762         rc = sclp_register(&sclp_vt220_register_input);
 763         if (rc)
 764                 goto out_reg;
 765         sclp_vt220_driver = driver;
 766         return 0;
 767
 768 out_reg:
 769         tty_unregister_driver(driver);
 770 out_init:
 771         __sclp_vt220_cleanup();
 772 out_driver:
 773         put_tty_driver(driver);
 774         return rc;
 775 }
 776 __initcall(sclp_vt220_tty_init);
 777
 778 static void __sclp_vt220_flush_buffer(void)
 779 {
 780         unsigned long flags;
 781
 782         sclp_vt220_emit_current();
 783         spin_lock_irqsave(&sclp_vt220_lock, flags);
 784         if (timer_pending(&sclp_vt220_timer))
 785                 del_timer(&sclp_vt220_timer);
 786         while (sclp_vt220_queue_running) {
 787                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 788                 sclp_sync_wait();
 789                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 790         }
 791         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 792 }
 793
 794 /*
 795  * Resume console: If there are cached messages, emit them.
 796  */
 797 static void sclp_vt220_resume(void)
 798 {
 799         unsigned long flags;
 800
 801         spin_lock_irqsave(&sclp_vt220_lock, flags);
 802         sclp_vt220_suspended = 0;
 803         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 804         sclp_vt220_emit_current();
 805 }
 806
 807 /*
 808  * Suspend console: Set suspend flag and flush console
 809  */
 810 static void sclp_vt220_suspend(void)
 811 {
 812         unsigned long flags;
 813
 814         spin_lock_irqsave(&sclp_vt220_lock, flags);
 815         sclp_vt220_suspended = 1;
 816         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 817         __sclp_vt220_flush_buffer();
 818 }
 819
 820 static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
 821                                    enum sclp_pm_event sclp_pm_event)
 822 {
 823         switch (sclp_pm_event) {
 824         case SCLP_PM_EVENT_FREEZE:
 825                 sclp_vt220_suspend();
 826                 break;
 827         case SCLP_PM_EVENT_RESTORE:
 828         case SCLP_PM_EVENT_THAW:
 829                 sclp_vt220_resume();
 830                 break;
 831         }
 832 }
 833
 834 #ifdef CONFIG_SCLP_VT220_CONSOLE
 835
 836 static void
 837 sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
 838 {
 839         __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
 840 }
 841
 842 static struct tty_driver *
 843 sclp_vt220_con_device(struct console *c, int *index)
 844 {
 845         *index = 0;
 846         return sclp_vt220_driver;
 847 }
 848
 849 static int
 850 sclp_vt220_notify(struct notifier_block *self,
 851                           unsigned long event, void *data)
 852 {
 853         __sclp_vt220_flush_buffer();
 854         return NOTIFY_OK;
 855 }
 856
 857 static struct notifier_block on_panic_nb = {
 858         .notifier_call = sclp_vt220_notify,
 859         .priority = 1,
 860 };
 861
 862 static struct notifier_block on_reboot_nb = {
 863         .notifier_call = sclp_vt220_notify,
 864         .priority = 1,
 865 };
 866
 867 /* Structure needed to register with printk */
 868 static struct console sclp_vt220_console =
 869 {
 870         .name = SCLP_VT220_CONSOLE_NAME,
 871         .write = sclp_vt220_con_write,
 872         .device = sclp_vt220_con_device,
 873         .flags = CON_PRINTBUFFER,
 874         .index = SCLP_VT220_CONSOLE_INDEX
 875 };
 876
 877 static int __init
 878 sclp_vt220_con_init(void)
 879 {
 880         int rc;
 881
 882         rc = __sclp_vt220_init(sclp_console_pages);
 883         if (rc)
 884                 return rc;
 885         /* Attach linux console */
 886         atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
 887         register_reboot_notifier(&on_reboot_nb);
 888         register_console(&sclp_vt220_console);
 889         return 0;
 890 }
 891
 892 console_initcall(sclp_vt220_con_init);
 893 #endif /* CONFIG_SCLP_VT220_CONSOLE */
 894