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 spinlock_t sclp_vt220_lock;
  65
  66 /* List of empty pages to be used as write request buffers */
  67 static struct list_head sclp_vt220_empty;
  68
  69 /* List of pending requests */
  70 static struct list_head sclp_vt220_outqueue;
  71
  72 /* 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(unsigned long data)
 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.function = sclp_vt220_timeout;
 458                 sclp_vt220_timer.data = 0UL;
 459                 sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
 460                 add_timer(&sclp_vt220_timer);
 461         }
 462 out:
 463         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 464         return overall_written;
 465 }
 466
 467 /*
 468  * This routine is called by the kernel to write a series of
 469  * characters to the tty device.  The characters may come from
 470  * user space or kernel space.  This routine will return the
 471  * number of characters actually accepted for writing.
 472  */
 473 static int
 474 sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
 475 {
 476         return __sclp_vt220_write(buf, count, 1, 0, 1);
 477 }
 478
 479 #define SCLP_VT220_SESSION_ENDED        0x01
 480 #define SCLP_VT220_SESSION_STARTED      0x80
 481 #define SCLP_VT220_SESSION_DATA         0x00
 482
 483 #ifdef CONFIG_MAGIC_SYSRQ
 484
 485 static int sysrq_pressed;
 486 static struct sysrq_work sysrq;
 487
 488 static void sclp_vt220_reset_session(void)
 489 {
 490         sysrq_pressed = 0;
 491 }
 492
 493 static void sclp_vt220_handle_input(const char *buffer, unsigned int count)
 494 {
 495         int i;
 496
 497         for (i = 0; i < count; i++) {
 498                 /* Handle magic sys request */
 499                 if (buffer[i] == ('O' ^ 0100)) { /* CTRL-O */
 500                         /*
 501                          * If pressed again, reset sysrq_pressed
 502                          * and flip CTRL-O character
 503                          */
 504                         sysrq_pressed = !sysrq_pressed;
 505                         if (sysrq_pressed)
 506                                 continue;
 507                 } else if (sysrq_pressed) {
 508                         sysrq.key = buffer[i];
 509                         schedule_sysrq_work(&sysrq);
 510                         sysrq_pressed = 0;
 511                         continue;
 512                 }
 513                 tty_insert_flip_char(&sclp_vt220_port, buffer[i], 0);
 514         }
 515 }
 516
 517 #else
 518
 519 static void sclp_vt220_reset_session(void)
 520 {
 521 }
 522
 523 static void sclp_vt220_handle_input(const char *buffer, unsigned int count)
 524 {
 525         tty_insert_flip_string(&sclp_vt220_port, buffer, count);
 526 }
 527
 528 #endif
 529
 530 /*
 531  * Called by the SCLP to report incoming event buffers.
 532  */
 533 static void
 534 sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
 535 {
 536         char *buffer;
 537         unsigned int count;
 538
 539         buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header));
 540         count = evbuf->length - sizeof(struct evbuf_header);
 541
 542         switch (*buffer) {
 543         case SCLP_VT220_SESSION_ENDED:
 544         case SCLP_VT220_SESSION_STARTED:
 545                 sclp_vt220_reset_session();
 546                 break;
 547         case SCLP_VT220_SESSION_DATA:
 548                 /* Send input to line discipline */
 549                 buffer++;
 550                 count--;
 551                 sclp_vt220_handle_input(buffer, count);
 552                 tty_flip_buffer_push(&sclp_vt220_port);
 553                 break;
 554         }
 555 }
 556
 557 /*
 558  * This routine is called when a particular tty device is opened.
 559  */
 560 static int
 561 sclp_vt220_open(struct tty_struct *tty, struct file *filp)
 562 {
 563         if (tty->count == 1) {
 564                 tty_port_tty_set(&sclp_vt220_port, tty);
 565                 sclp_vt220_port.low_latency = 0;
 566                 if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
 567                         tty->winsize.ws_row = 24;
 568                         tty->winsize.ws_col = 80;
 569                 }
 570         }
 571         return 0;
 572 }
 573
 574 /*
 575  * This routine is called when a particular tty device is closed.
 576  */
 577 static void
 578 sclp_vt220_close(struct tty_struct *tty, struct file *filp)
 579 {
 580         if (tty->count == 1)
 581                 tty_port_tty_set(&sclp_vt220_port, NULL);
 582 }
 583
 584 /*
 585  * This routine is called by the kernel to write a single
 586  * character to the tty device.  If the kernel uses this routine,
 587  * it must call the flush_chars() routine (if defined) when it is
 588  * done stuffing characters into the driver.
 589  */
 590 static int
 591 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
 592 {
 593         return __sclp_vt220_write(&ch, 1, 0, 0, 1);
 594 }
 595
 596 /*
 597  * This routine is called by the kernel after it has written a
 598  * series of characters to the tty device using put_char().
 599  */
 600 static void
 601 sclp_vt220_flush_chars(struct tty_struct *tty)
 602 {
 603         if (!sclp_vt220_queue_running)
 604                 sclp_vt220_emit_current();
 605         else
 606                 sclp_vt220_flush_later = 1;
 607 }
 608
 609 /*
 610  * This routine returns the numbers of characters the tty driver
 611  * will accept for queuing to be written.  This number is subject
 612  * to change as output buffers get emptied, or if the output flow
 613  * control is acted.
 614  */
 615 static int
 616 sclp_vt220_write_room(struct tty_struct *tty)
 617 {
 618         unsigned long flags;
 619         struct list_head *l;
 620         int count;
 621
 622         spin_lock_irqsave(&sclp_vt220_lock, flags);
 623         count = 0;
 624         if (sclp_vt220_current_request != NULL)
 625                 count = sclp_vt220_space_left(sclp_vt220_current_request);
 626         list_for_each(l, &sclp_vt220_empty)
 627                 count += SCLP_VT220_MAX_CHARS_PER_BUFFER;
 628         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 629         return count;
 630 }
 631
 632 /*
 633  * Return number of buffered chars.
 634  */
 635 static int
 636 sclp_vt220_chars_in_buffer(struct tty_struct *tty)
 637 {
 638         unsigned long flags;
 639         struct list_head *l;
 640         struct sclp_vt220_request *r;
 641         int count;
 642
 643         spin_lock_irqsave(&sclp_vt220_lock, flags);
 644         count = 0;
 645         if (sclp_vt220_current_request != NULL)
 646                 count = sclp_vt220_chars_stored(sclp_vt220_current_request);
 647         list_for_each(l, &sclp_vt220_outqueue) {
 648                 r = list_entry(l, struct sclp_vt220_request, list);
 649                 count += sclp_vt220_chars_stored(r);
 650         }
 651         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 652         return count;
 653 }
 654
 655 /*
 656  * Pass on all buffers to the hardware. Return only when there are no more
 657  * buffers pending.
 658  */
 659 static void
 660 sclp_vt220_flush_buffer(struct tty_struct *tty)
 661 {
 662         sclp_vt220_emit_current();
 663 }
 664
 665 /* Release allocated pages. */
 666 static void __init __sclp_vt220_free_pages(void)
 667 {
 668         struct list_head *page, *p;
 669
 670         list_for_each_safe(page, p, &sclp_vt220_empty) {
 671                 list_del(page);
 672                 free_page((unsigned long) page);
 673         }
 674 }
 675
 676 /* Release memory and unregister from sclp core. Controlled by init counting -
 677  * only the last invoker will actually perform these actions. */
 678 static void __init __sclp_vt220_cleanup(void)
 679 {
 680         sclp_vt220_init_count--;
 681         if (sclp_vt220_init_count != 0)
 682                 return;
 683         sclp_unregister(&sclp_vt220_register);
 684         __sclp_vt220_free_pages();
 685         tty_port_destroy(&sclp_vt220_port);
 686 }
 687
 688 /* Allocate buffer pages and register with sclp core. Controlled by init
 689  * counting - only the first invoker will actually perform these actions. */
 690 static int __init __sclp_vt220_init(int num_pages)
 691 {
 692         void *page;
 693         int i;
 694         int rc;
 695
 696         sclp_vt220_init_count++;
 697         if (sclp_vt220_init_count != 1)
 698                 return 0;
 699         spin_lock_init(&sclp_vt220_lock);
 700         INIT_LIST_HEAD(&sclp_vt220_empty);
 701         INIT_LIST_HEAD(&sclp_vt220_outqueue);
 702         init_timer(&sclp_vt220_timer);
 703         tty_port_init(&sclp_vt220_port);
 704         sclp_vt220_current_request = NULL;
 705         sclp_vt220_buffered_chars = 0;
 706         sclp_vt220_flush_later = 0;
 707
 708         /* Allocate pages for output buffering */
 709         rc = -ENOMEM;
 710         for (i = 0; i < num_pages; i++) {
 711                 page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 712                 if (!page)
 713                         goto out;
 714                 list_add_tail(page, &sclp_vt220_empty);
 715         }
 716         rc = sclp_register(&sclp_vt220_register);
 717 out:
 718         if (rc) {
 719                 __sclp_vt220_free_pages();
 720                 sclp_vt220_init_count--;
 721                 tty_port_destroy(&sclp_vt220_port);
 722         }
 723         return rc;
 724 }
 725
 726 static const struct tty_operations sclp_vt220_ops = {
 727         .open = sclp_vt220_open,
 728         .close = sclp_vt220_close,
 729         .write = sclp_vt220_write,
 730         .put_char = sclp_vt220_put_char,
 731         .flush_chars = sclp_vt220_flush_chars,
 732         .write_room = sclp_vt220_write_room,
 733         .chars_in_buffer = sclp_vt220_chars_in_buffer,
 734         .flush_buffer = sclp_vt220_flush_buffer,
 735 };
 736
 737 /*
 738  * Register driver with SCLP and Linux and initialize internal tty structures.
 739  */
 740 static int __init sclp_vt220_tty_init(void)
 741 {
 742         struct tty_driver *driver;
 743         int rc;
 744
 745         /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
 746          * symmetry between VM and LPAR systems regarding ttyS1. */
 747         driver = alloc_tty_driver(1);
 748         if (!driver)
 749                 return -ENOMEM;
 750         rc = __sclp_vt220_init(MAX_KMEM_PAGES);
 751         if (rc)
 752                 goto out_driver;
 753
 754         driver->driver_name = SCLP_VT220_DRIVER_NAME;
 755         driver->name = SCLP_VT220_DEVICE_NAME;
 756         driver->major = SCLP_VT220_MAJOR;
 757         driver->minor_start = SCLP_VT220_MINOR;
 758         driver->type = TTY_DRIVER_TYPE_SYSTEM;
 759         driver->subtype = SYSTEM_TYPE_TTY;
 760         driver->init_termios = tty_std_termios;
 761         driver->flags = TTY_DRIVER_REAL_RAW;
 762         tty_set_operations(driver, &sclp_vt220_ops);
 763         tty_port_link_device(&sclp_vt220_port, driver, 0);
 764
 765         rc = tty_register_driver(driver);
 766         if (rc)
 767                 goto out_init;
 768         rc = sclp_register(&sclp_vt220_register_input);
 769         if (rc)
 770                 goto out_reg;
 771         sclp_vt220_driver = driver;
 772         return 0;
 773
 774 out_reg:
 775         tty_unregister_driver(driver);
 776 out_init:
 777         __sclp_vt220_cleanup();
 778 out_driver:
 779         put_tty_driver(driver);
 780         return rc;
 781 }
 782 __initcall(sclp_vt220_tty_init);
 783
 784 static void __sclp_vt220_flush_buffer(void)
 785 {
 786         unsigned long flags;
 787
 788         sclp_vt220_emit_current();
 789         spin_lock_irqsave(&sclp_vt220_lock, flags);
 790         if (timer_pending(&sclp_vt220_timer))
 791                 del_timer(&sclp_vt220_timer);
 792         while (sclp_vt220_queue_running) {
 793                 spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 794                 sclp_sync_wait();
 795                 spin_lock_irqsave(&sclp_vt220_lock, flags);
 796         }
 797         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 798 }
 799
 800 /*
 801  * Resume console: If there are cached messages, emit them.
 802  */
 803 static void sclp_vt220_resume(void)
 804 {
 805         unsigned long flags;
 806
 807         spin_lock_irqsave(&sclp_vt220_lock, flags);
 808         sclp_vt220_suspended = 0;
 809         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 810         sclp_vt220_emit_current();
 811 }
 812
 813 /*
 814  * Suspend console: Set suspend flag and flush console
 815  */
 816 static void sclp_vt220_suspend(void)
 817 {
 818         unsigned long flags;
 819
 820         spin_lock_irqsave(&sclp_vt220_lock, flags);
 821         sclp_vt220_suspended = 1;
 822         spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 823         __sclp_vt220_flush_buffer();
 824 }
 825
 826 static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
 827                                    enum sclp_pm_event sclp_pm_event)
 828 {
 829         switch (sclp_pm_event) {
 830         case SCLP_PM_EVENT_FREEZE:
 831                 sclp_vt220_suspend();
 832                 break;
 833         case SCLP_PM_EVENT_RESTORE:
 834         case SCLP_PM_EVENT_THAW:
 835                 sclp_vt220_resume();
 836                 break;
 837         }
 838 }
 839
 840 #ifdef CONFIG_SCLP_VT220_CONSOLE
 841
 842 static void
 843 sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count)
 844 {
 845         __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0);
 846 }
 847
 848 static struct tty_driver *
 849 sclp_vt220_con_device(struct console *c, int *index)
 850 {
 851         *index = 0;
 852         return sclp_vt220_driver;
 853 }
 854
 855 static int
 856 sclp_vt220_notify(struct notifier_block *self,
 857                           unsigned long event, void *data)
 858 {
 859         __sclp_vt220_flush_buffer();
 860         return NOTIFY_OK;
 861 }
 862
 863 static struct notifier_block on_panic_nb = {
 864         .notifier_call = sclp_vt220_notify,
 865         .priority = 1,
 866 };
 867
 868 static struct notifier_block on_reboot_nb = {
 869         .notifier_call = sclp_vt220_notify,
 870         .priority = 1,
 871 };
 872
 873 /* Structure needed to register with printk */
 874 static struct console sclp_vt220_console =
 875 {
 876         .name = SCLP_VT220_CONSOLE_NAME,
 877         .write = sclp_vt220_con_write,
 878         .device = sclp_vt220_con_device,
 879         .flags = CON_PRINTBUFFER,
 880         .index = SCLP_VT220_CONSOLE_INDEX
 881 };
 882
 883 static int __init
 884 sclp_vt220_con_init(void)
 885 {
 886         int rc;
 887
 888         rc = __sclp_vt220_init(sclp_console_pages);
 889         if (rc)
 890                 return rc;
 891         /* Attach linux console */
 892         atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
 893         register_reboot_notifier(&on_reboot_nb);
 894         register_console(&sclp_vt220_console);
 895         return 0;
 896 }
 897
 898 console_initcall(sclp_vt220_con_init);
 899 #endif /* CONFIG_SCLP_VT220_CONSOLE */
 900