1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM 4 * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM 5 * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp. 6 * Copyright (C) 2004 IBM Corporation 7 * 8 * Additional Author(s): 9 * Ryan S. Arnold <rsa@us.ibm.com> 10 */ 11 12 #include <linux/console.h> 13 #include <linux/cpumask.h> 14 #include <linux/init.h> 15 #include <linux/kbd_kern.h> 16 #include <linux/kernel.h> 17 #include <linux/kthread.h> 18 #include <linux/list.h> 19 #include <linux/major.h> 20 #include <linux/atomic.h> 21 #include <linux/sysrq.h> 22 #include <linux/tty.h> 23 #include <linux/tty_flip.h> 24 #include <linux/sched.h> 25 #include <linux/spinlock.h> 26 #include <linux/delay.h> 27 #include <linux/freezer.h> 28 #include <linux/slab.h> 29 #include <linux/serial_core.h> 30 31 #include <linux/uaccess.h> 32 33 #include "hvc_console.h" 34 35 #define HVC_MAJOR 229 36 #define HVC_MINOR 0 37 38 /* 39 * Wait this long per iteration while trying to push buffered data to the 40 * hypervisor before allowing the tty to complete a close operation. 41 */ 42 #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ 43 44 /* 45 * These sizes are most efficient for vio, because they are the 46 * native transfer size. We could make them selectable in the 47 * future to better deal with backends that want other buffer sizes. 48 */ 49 #define N_OUTBUF 16 50 #define N_INBUF 16 51 52 #define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) 53 54 static struct tty_driver *hvc_driver; 55 static struct task_struct *hvc_task; 56 57 /* Picks up late kicks after list walk but before schedule() */ 58 static int hvc_kicked; 59 60 /* hvc_init is triggered from hvc_alloc, i.e. only when actually used */ 61 static atomic_t hvc_needs_init __read_mostly = ATOMIC_INIT(-1); 62 63 static int hvc_init(void); 64 65 #ifdef CONFIG_MAGIC_SYSRQ 66 static int sysrq_pressed; 67 #endif 68 69 /* dynamic list of hvc_struct instances */ 70 static LIST_HEAD(hvc_structs); 71 72 /* 73 * Protect the list of hvc_struct instances from inserts and removals during 74 * list traversal. 75 */ 76 static DEFINE_SPINLOCK(hvc_structs_lock); 77 78 /* 79 * This value is used to assign a tty->index value to a hvc_struct based 80 * upon order of exposure via hvc_probe(), when we can not match it to 81 * a console candidate registered with hvc_instantiate(). 82 */ 83 static int last_hvc = -1; 84 85 /* 86 * Do not call this function with either the hvc_structs_lock or the hvc_struct 87 * lock held. If successful, this function increments the kref reference 88 * count against the target hvc_struct so it should be released when finished. 89 */ 90 static struct hvc_struct *hvc_get_by_index(int index) 91 { 92 struct hvc_struct *hp; 93 unsigned long flags; 94 95 spin_lock(&hvc_structs_lock); 96 97 list_for_each_entry(hp, &hvc_structs, next) { 98 spin_lock_irqsave(&hp->lock, flags); 99 if (hp->index == index) { 100 tty_port_get(&hp->port); 101 spin_unlock_irqrestore(&hp->lock, flags); 102 spin_unlock(&hvc_structs_lock); 103 return hp; 104 } 105 spin_unlock_irqrestore(&hp->lock, flags); 106 } 107 hp = NULL; 108 109 spin_unlock(&hvc_structs_lock); 110 return hp; 111 } 112 113 114 /* 115 * Initial console vtermnos for console API usage prior to full console 116 * initialization. Any vty adapter outside this range will not have usable 117 * console interfaces but can still be used as a tty device. This has to be 118 * static because kmalloc will not work during early console init. 119 */ 120 static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES]; 121 static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] = 122 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1}; 123 124 /* 125 * Console APIs, NOT TTY. These APIs are available immediately when 126 * hvc_console_setup() finds adapters. 127 */ 128 129 static void hvc_console_print(struct console *co, const char *b, 130 unsigned count) 131 { 132 char c[N_OUTBUF] __ALIGNED__; 133 unsigned i = 0, n = 0; 134 int r, donecr = 0, index = co->index; 135 136 /* Console access attempt outside of acceptable console range. */ 137 if (index >= MAX_NR_HVC_CONSOLES) 138 return; 139 140 /* This console adapter was removed so it is not usable. */ 141 if (vtermnos[index] == -1) 142 return; 143 144 while (count > 0 || i > 0) { 145 if (count > 0 && i < sizeof(c)) { 146 if (b[n] == '\n' && !donecr) { 147 c[i++] = '\r'; 148 donecr = 1; 149 } else { 150 c[i++] = b[n++]; 151 donecr = 0; 152 --count; 153 } 154 } else { 155 r = cons_ops[index]->put_chars(vtermnos[index], c, i); 156 if (r <= 0) { 157 /* throw away characters on error 158 * but spin in case of -EAGAIN */ 159 if (r != -EAGAIN) 160 i = 0; 161 } else if (r > 0) { 162 i -= r; 163 if (i > 0) 164 memmove(c, c+r, i); 165 } 166 } 167 } 168 } 169 170 static struct tty_driver *hvc_console_device(struct console *c, int *index) 171 { 172 if (vtermnos[c->index] == -1) 173 return NULL; 174 175 *index = c->index; 176 return hvc_driver; 177 } 178 179 static int hvc_console_setup(struct console *co, char *options) 180 { 181 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES) 182 return -ENODEV; 183 184 if (vtermnos[co->index] == -1) 185 return -ENODEV; 186 187 return 0; 188 } 189 190 static struct console hvc_console = { 191 .name = "hvc", 192 .write = hvc_console_print, 193 .device = hvc_console_device, 194 .setup = hvc_console_setup, 195 .flags = CON_PRINTBUFFER, 196 .index = -1, 197 }; 198 199 /* 200 * Early console initialization. Precedes driver initialization. 201 * 202 * (1) we are first, and the user specified another driver 203 * -- index will remain -1 204 * (2) we are first and the user specified no driver 205 * -- index will be set to 0, then we will fail setup. 206 * (3) we are first and the user specified our driver 207 * -- index will be set to user specified driver, and we will fail 208 * (4) we are after driver, and this initcall will register us 209 * -- if the user didn't specify a driver then the console will match 210 * 211 * Note that for cases 2 and 3, we will match later when the io driver 212 * calls hvc_instantiate() and call register again. 213 */ 214 static int __init hvc_console_init(void) 215 { 216 register_console(&hvc_console); 217 return 0; 218 } 219 console_initcall(hvc_console_init); 220 221 /* callback when the kboject ref count reaches zero. */ 222 static void hvc_port_destruct(struct tty_port *port) 223 { 224 struct hvc_struct *hp = container_of(port, struct hvc_struct, port); 225 unsigned long flags; 226 227 spin_lock(&hvc_structs_lock); 228 229 spin_lock_irqsave(&hp->lock, flags); 230 list_del(&(hp->next)); 231 spin_unlock_irqrestore(&hp->lock, flags); 232 233 spin_unlock(&hvc_structs_lock); 234 235 kfree(hp); 236 } 237 238 static void hvc_check_console(int index) 239 { 240 /* Already enabled, bail out */ 241 if (hvc_console.flags & CON_ENABLED) 242 return; 243 244 /* If this index is what the user requested, then register 245 * now (setup won't fail at this point). It's ok to just 246 * call register again if previously .setup failed. 247 */ 248 if (index == hvc_console.index) 249 register_console(&hvc_console); 250 } 251 252 /* 253 * hvc_instantiate() is an early console discovery method which locates 254 * consoles * prior to the vio subsystem discovering them. Hotplugged 255 * vty adapters do NOT get an hvc_instantiate() callback since they 256 * appear after early console init. 257 */ 258 int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops) 259 { 260 struct hvc_struct *hp; 261 262 if (index < 0 || index >= MAX_NR_HVC_CONSOLES) 263 return -1; 264 265 if (vtermnos[index] != -1) 266 return -1; 267 268 /* make sure no no tty has been registered in this index */ 269 hp = hvc_get_by_index(index); 270 if (hp) { 271 tty_port_put(&hp->port); 272 return -1; 273 } 274 275 vtermnos[index] = vtermno; 276 cons_ops[index] = ops; 277 278 /* reserve all indices up to and including this index */ 279 if (last_hvc < index) 280 last_hvc = index; 281 282 /* check if we need to re-register the kernel console */ 283 hvc_check_console(index); 284 285 return 0; 286 } 287 EXPORT_SYMBOL_GPL(hvc_instantiate); 288 289 /* Wake the sleeping khvcd */ 290 void hvc_kick(void) 291 { 292 hvc_kicked = 1; 293 wake_up_process(hvc_task); 294 } 295 EXPORT_SYMBOL_GPL(hvc_kick); 296 297 static void hvc_unthrottle(struct tty_struct *tty) 298 { 299 hvc_kick(); 300 } 301 302 static int hvc_install(struct tty_driver *driver, struct tty_struct *tty) 303 { 304 struct hvc_struct *hp; 305 int rc; 306 307 /* Auto increments kref reference if found. */ 308 hp = hvc_get_by_index(tty->index); 309 if (!hp) 310 return -ENODEV; 311 312 tty->driver_data = hp; 313 314 rc = tty_port_install(&hp->port, driver, tty); 315 if (rc) 316 tty_port_put(&hp->port); 317 return rc; 318 } 319 320 /* 321 * The TTY interface won't be used until after the vio layer has exposed the vty 322 * adapter to the kernel. 323 */ 324 static int hvc_open(struct tty_struct *tty, struct file * filp) 325 { 326 struct hvc_struct *hp = tty->driver_data; 327 unsigned long flags; 328 int rc = 0; 329 330 spin_lock_irqsave(&hp->port.lock, flags); 331 /* Check and then increment for fast path open. */ 332 if (hp->port.count++ > 0) { 333 spin_unlock_irqrestore(&hp->port.lock, flags); 334 hvc_kick(); 335 return 0; 336 } /* else count == 0 */ 337 spin_unlock_irqrestore(&hp->port.lock, flags); 338 339 tty_port_tty_set(&hp->port, tty); 340 341 if (hp->ops->notifier_add) 342 rc = hp->ops->notifier_add(hp, hp->data); 343 344 /* 345 * If the notifier fails we return an error. The tty layer 346 * will call hvc_close() after a failed open but we don't want to clean 347 * up there so we'll clean up here and clear out the previously set 348 * tty fields and return the kref reference. 349 */ 350 if (rc) { 351 tty_port_tty_set(&hp->port, NULL); 352 tty->driver_data = NULL; 353 tty_port_put(&hp->port); 354 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); 355 } else 356 /* We are ready... raise DTR/RTS */ 357 if (C_BAUD(tty)) 358 if (hp->ops->dtr_rts) 359 hp->ops->dtr_rts(hp, 1); 360 361 /* Force wakeup of the polling thread */ 362 hvc_kick(); 363 364 return rc; 365 } 366 367 static void hvc_close(struct tty_struct *tty, struct file * filp) 368 { 369 struct hvc_struct *hp; 370 unsigned long flags; 371 372 if (tty_hung_up_p(filp)) 373 return; 374 375 /* 376 * No driver_data means that this close was issued after a failed 377 * hvc_open by the tty layer's release_dev() function and we can just 378 * exit cleanly because the kref reference wasn't made. 379 */ 380 if (!tty->driver_data) 381 return; 382 383 hp = tty->driver_data; 384 385 spin_lock_irqsave(&hp->port.lock, flags); 386 387 if (--hp->port.count == 0) { 388 spin_unlock_irqrestore(&hp->port.lock, flags); 389 /* We are done with the tty pointer now. */ 390 tty_port_tty_set(&hp->port, NULL); 391 392 if (C_HUPCL(tty)) 393 if (hp->ops->dtr_rts) 394 hp->ops->dtr_rts(hp, 0); 395 396 if (hp->ops->notifier_del) 397 hp->ops->notifier_del(hp, hp->data); 398 399 /* cancel pending tty resize work */ 400 cancel_work_sync(&hp->tty_resize); 401 402 /* 403 * Chain calls chars_in_buffer() and returns immediately if 404 * there is no buffered data otherwise sleeps on a wait queue 405 * waking periodically to check chars_in_buffer(). 406 */ 407 tty_wait_until_sent(tty, HVC_CLOSE_WAIT); 408 } else { 409 if (hp->port.count < 0) 410 printk(KERN_ERR "hvc_close %X: oops, count is %d\n", 411 hp->vtermno, hp->port.count); 412 spin_unlock_irqrestore(&hp->port.lock, flags); 413 } 414 } 415 416 static void hvc_cleanup(struct tty_struct *tty) 417 { 418 struct hvc_struct *hp = tty->driver_data; 419 420 tty_port_put(&hp->port); 421 } 422 423 static void hvc_hangup(struct tty_struct *tty) 424 { 425 struct hvc_struct *hp = tty->driver_data; 426 unsigned long flags; 427 428 if (!hp) 429 return; 430 431 /* cancel pending tty resize work */ 432 cancel_work_sync(&hp->tty_resize); 433 434 spin_lock_irqsave(&hp->port.lock, flags); 435 436 /* 437 * The N_TTY line discipline has problems such that in a close vs 438 * open->hangup case this can be called after the final close so prevent 439 * that from happening for now. 440 */ 441 if (hp->port.count <= 0) { 442 spin_unlock_irqrestore(&hp->port.lock, flags); 443 return; 444 } 445 446 hp->port.count = 0; 447 spin_unlock_irqrestore(&hp->port.lock, flags); 448 tty_port_tty_set(&hp->port, NULL); 449 450 hp->n_outbuf = 0; 451 452 if (hp->ops->notifier_hangup) 453 hp->ops->notifier_hangup(hp, hp->data); 454 } 455 456 /* 457 * Push buffered characters whether they were just recently buffered or waiting 458 * on a blocked hypervisor. Call this function with hp->lock held. 459 */ 460 static int hvc_push(struct hvc_struct *hp) 461 { 462 int n; 463 464 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); 465 if (n <= 0) { 466 if (n == 0 || n == -EAGAIN) { 467 hp->do_wakeup = 1; 468 return 0; 469 } 470 /* throw away output on error; this happens when 471 there is no session connected to the vterm. */ 472 hp->n_outbuf = 0; 473 } else 474 hp->n_outbuf -= n; 475 if (hp->n_outbuf > 0) 476 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); 477 else 478 hp->do_wakeup = 1; 479 480 return n; 481 } 482 483 static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) 484 { 485 struct hvc_struct *hp = tty->driver_data; 486 unsigned long flags; 487 int rsize, written = 0; 488 489 /* This write was probably executed during a tty close. */ 490 if (!hp) 491 return -EPIPE; 492 493 /* FIXME what's this (unprotected) check for? */ 494 if (hp->port.count <= 0) 495 return -EIO; 496 497 spin_lock_irqsave(&hp->lock, flags); 498 499 /* Push pending writes */ 500 if (hp->n_outbuf > 0) 501 hvc_push(hp); 502 503 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) { 504 if (rsize > count) 505 rsize = count; 506 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); 507 count -= rsize; 508 buf += rsize; 509 hp->n_outbuf += rsize; 510 written += rsize; 511 hvc_push(hp); 512 } 513 spin_unlock_irqrestore(&hp->lock, flags); 514 515 /* 516 * Racy, but harmless, kick thread if there is still pending data. 517 */ 518 if (hp->n_outbuf) 519 hvc_kick(); 520 521 return written; 522 } 523 524 /** 525 * hvc_set_winsz() - Resize the hvc tty terminal window. 526 * @work: work structure. 527 * 528 * The routine shall not be called within an atomic context because it 529 * might sleep. 530 * 531 * Locking: hp->lock 532 */ 533 static void hvc_set_winsz(struct work_struct *work) 534 { 535 struct hvc_struct *hp; 536 unsigned long hvc_flags; 537 struct tty_struct *tty; 538 struct winsize ws; 539 540 hp = container_of(work, struct hvc_struct, tty_resize); 541 542 tty = tty_port_tty_get(&hp->port); 543 if (!tty) 544 return; 545 546 spin_lock_irqsave(&hp->lock, hvc_flags); 547 ws = hp->ws; 548 spin_unlock_irqrestore(&hp->lock, hvc_flags); 549 550 tty_do_resize(tty, &ws); 551 tty_kref_put(tty); 552 } 553 554 /* 555 * This is actually a contract between the driver and the tty layer outlining 556 * how much write room the driver can guarantee will be sent OR BUFFERED. This 557 * driver MUST honor the return value. 558 */ 559 static int hvc_write_room(struct tty_struct *tty) 560 { 561 struct hvc_struct *hp = tty->driver_data; 562 563 if (!hp) 564 return 0; 565 566 return hp->outbuf_size - hp->n_outbuf; 567 } 568 569 static int hvc_chars_in_buffer(struct tty_struct *tty) 570 { 571 struct hvc_struct *hp = tty->driver_data; 572 573 if (!hp) 574 return 0; 575 return hp->n_outbuf; 576 } 577 578 /* 579 * timeout will vary between the MIN and MAX values defined here. By default 580 * and during console activity we will use a default MIN_TIMEOUT of 10. When 581 * the console is idle, we increase the timeout value on each pass through 582 * msleep until we reach the max. This may be noticeable as a brief (average 583 * one second) delay on the console before the console responds to input when 584 * there has been no input for some time. 585 */ 586 #define MIN_TIMEOUT (10) 587 #define MAX_TIMEOUT (2000) 588 static u32 timeout = MIN_TIMEOUT; 589 590 #define HVC_POLL_READ 0x00000001 591 #define HVC_POLL_WRITE 0x00000002 592 593 int hvc_poll(struct hvc_struct *hp) 594 { 595 struct tty_struct *tty; 596 int i, n, poll_mask = 0; 597 char buf[N_INBUF] __ALIGNED__; 598 unsigned long flags; 599 int read_total = 0; 600 int written_total = 0; 601 602 spin_lock_irqsave(&hp->lock, flags); 603 604 /* Push pending writes */ 605 if (hp->n_outbuf > 0) 606 written_total = hvc_push(hp); 607 608 /* Reschedule us if still some write pending */ 609 if (hp->n_outbuf > 0) { 610 poll_mask |= HVC_POLL_WRITE; 611 /* If hvc_push() was not able to write, sleep a few msecs */ 612 timeout = (written_total) ? 0 : MIN_TIMEOUT; 613 } 614 615 /* No tty attached, just skip */ 616 tty = tty_port_tty_get(&hp->port); 617 if (tty == NULL) 618 goto bail; 619 620 /* Now check if we can get data (are we throttled ?) */ 621 if (tty_throttled(tty)) 622 goto throttled; 623 624 /* If we aren't notifier driven and aren't throttled, we always 625 * request a reschedule 626 */ 627 if (!hp->irq_requested) 628 poll_mask |= HVC_POLL_READ; 629 630 /* Read data if any */ 631 for (;;) { 632 int count = tty_buffer_request_room(&hp->port, N_INBUF); 633 634 /* If flip is full, just reschedule a later read */ 635 if (count == 0) { 636 poll_mask |= HVC_POLL_READ; 637 break; 638 } 639 640 n = hp->ops->get_chars(hp->vtermno, buf, count); 641 if (n <= 0) { 642 /* Hangup the tty when disconnected from host */ 643 if (n == -EPIPE) { 644 spin_unlock_irqrestore(&hp->lock, flags); 645 tty_hangup(tty); 646 spin_lock_irqsave(&hp->lock, flags); 647 } else if ( n == -EAGAIN ) { 648 /* 649 * Some back-ends can only ensure a certain min 650 * num of bytes read, which may be > 'count'. 651 * Let the tty clear the flip buff to make room. 652 */ 653 poll_mask |= HVC_POLL_READ; 654 } 655 break; 656 } 657 for (i = 0; i < n; ++i) { 658 #ifdef CONFIG_MAGIC_SYSRQ 659 if (hp->index == hvc_console.index) { 660 /* Handle the SysRq Hack */ 661 /* XXX should support a sequence */ 662 if (buf[i] == '\x0f') { /* ^O */ 663 /* if ^O is pressed again, reset 664 * sysrq_pressed and flip ^O char */ 665 sysrq_pressed = !sysrq_pressed; 666 if (sysrq_pressed) 667 continue; 668 } else if (sysrq_pressed) { 669 handle_sysrq(buf[i]); 670 sysrq_pressed = 0; 671 continue; 672 } 673 } 674 #endif /* CONFIG_MAGIC_SYSRQ */ 675 tty_insert_flip_char(&hp->port, buf[i], 0); 676 } 677 678 read_total += n; 679 } 680 throttled: 681 /* Wakeup write queue if necessary */ 682 if (hp->do_wakeup) { 683 hp->do_wakeup = 0; 684 tty_wakeup(tty); 685 } 686 bail: 687 spin_unlock_irqrestore(&hp->lock, flags); 688 689 if (read_total) { 690 /* Activity is occurring, so reset the polling backoff value to 691 a minimum for performance. */ 692 timeout = MIN_TIMEOUT; 693 694 tty_flip_buffer_push(&hp->port); 695 } 696 tty_kref_put(tty); 697 698 return poll_mask; 699 } 700 EXPORT_SYMBOL_GPL(hvc_poll); 701 702 /** 703 * __hvc_resize() - Update terminal window size information. 704 * @hp: HVC console pointer 705 * @ws: Terminal window size structure 706 * 707 * Stores the specified window size information in the hvc structure of @hp. 708 * The function schedule the tty resize update. 709 * 710 * Locking: Locking free; the function MUST be called holding hp->lock 711 */ 712 void __hvc_resize(struct hvc_struct *hp, struct winsize ws) 713 { 714 hp->ws = ws; 715 schedule_work(&hp->tty_resize); 716 } 717 EXPORT_SYMBOL_GPL(__hvc_resize); 718 719 /* 720 * This kthread is either polling or interrupt driven. This is determined by 721 * calling hvc_poll() who determines whether a console adapter support 722 * interrupts. 723 */ 724 static int khvcd(void *unused) 725 { 726 int poll_mask; 727 struct hvc_struct *hp; 728 729 set_freezable(); 730 do { 731 poll_mask = 0; 732 hvc_kicked = 0; 733 try_to_freeze(); 734 wmb(); 735 if (!cpus_are_in_xmon()) { 736 spin_lock(&hvc_structs_lock); 737 list_for_each_entry(hp, &hvc_structs, next) { 738 poll_mask |= hvc_poll(hp); 739 } 740 spin_unlock(&hvc_structs_lock); 741 } else 742 poll_mask |= HVC_POLL_READ; 743 if (hvc_kicked) 744 continue; 745 set_current_state(TASK_INTERRUPTIBLE); 746 if (!hvc_kicked) { 747 if (poll_mask == 0) 748 schedule(); 749 else { 750 unsigned long j_timeout; 751 752 if (timeout < MAX_TIMEOUT) 753 timeout += (timeout >> 6) + 1; 754 755 /* 756 * We don't use msleep_interruptible otherwise 757 * "kick" will fail to wake us up 758 */ 759 j_timeout = msecs_to_jiffies(timeout) + 1; 760 schedule_timeout_interruptible(j_timeout); 761 } 762 } 763 __set_current_state(TASK_RUNNING); 764 } while (!kthread_should_stop()); 765 766 return 0; 767 } 768 769 static int hvc_tiocmget(struct tty_struct *tty) 770 { 771 struct hvc_struct *hp = tty->driver_data; 772 773 if (!hp || !hp->ops->tiocmget) 774 return -EINVAL; 775 return hp->ops->tiocmget(hp); 776 } 777 778 static int hvc_tiocmset(struct tty_struct *tty, 779 unsigned int set, unsigned int clear) 780 { 781 struct hvc_struct *hp = tty->driver_data; 782 783 if (!hp || !hp->ops->tiocmset) 784 return -EINVAL; 785 return hp->ops->tiocmset(hp, set, clear); 786 } 787 788 #ifdef CONFIG_CONSOLE_POLL 789 static int hvc_poll_init(struct tty_driver *driver, int line, char *options) 790 { 791 return 0; 792 } 793 794 static int hvc_poll_get_char(struct tty_driver *driver, int line) 795 { 796 struct tty_struct *tty = driver->ttys[0]; 797 struct hvc_struct *hp = tty->driver_data; 798 int n; 799 char ch; 800 801 n = hp->ops->get_chars(hp->vtermno, &ch, 1); 802 803 if (n <= 0) 804 return NO_POLL_CHAR; 805 806 return ch; 807 } 808 809 static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch) 810 { 811 struct tty_struct *tty = driver->ttys[0]; 812 struct hvc_struct *hp = tty->driver_data; 813 int n; 814 815 do { 816 n = hp->ops->put_chars(hp->vtermno, &ch, 1); 817 } while (n <= 0); 818 } 819 #endif 820 821 static const struct tty_operations hvc_ops = { 822 .install = hvc_install, 823 .open = hvc_open, 824 .close = hvc_close, 825 .cleanup = hvc_cleanup, 826 .write = hvc_write, 827 .hangup = hvc_hangup, 828 .unthrottle = hvc_unthrottle, 829 .write_room = hvc_write_room, 830 .chars_in_buffer = hvc_chars_in_buffer, 831 .tiocmget = hvc_tiocmget, 832 .tiocmset = hvc_tiocmset, 833 #ifdef CONFIG_CONSOLE_POLL 834 .poll_init = hvc_poll_init, 835 .poll_get_char = hvc_poll_get_char, 836 .poll_put_char = hvc_poll_put_char, 837 #endif 838 }; 839 840 static const struct tty_port_operations hvc_port_ops = { 841 .destruct = hvc_port_destruct, 842 }; 843 844 struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, 845 const struct hv_ops *ops, 846 int outbuf_size) 847 { 848 struct hvc_struct *hp; 849 int i; 850 851 /* We wait until a driver actually comes along */ 852 if (atomic_inc_not_zero(&hvc_needs_init)) { 853 int err = hvc_init(); 854 if (err) 855 return ERR_PTR(err); 856 } 857 858 hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, 859 GFP_KERNEL); 860 if (!hp) 861 return ERR_PTR(-ENOMEM); 862 863 hp->vtermno = vtermno; 864 hp->data = data; 865 hp->ops = ops; 866 hp->outbuf_size = outbuf_size; 867 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; 868 869 tty_port_init(&hp->port); 870 hp->port.ops = &hvc_port_ops; 871 872 INIT_WORK(&hp->tty_resize, hvc_set_winsz); 873 spin_lock_init(&hp->lock); 874 spin_lock(&hvc_structs_lock); 875 876 /* 877 * find index to use: 878 * see if this vterm id matches one registered for console. 879 */ 880 for (i=0; i < MAX_NR_HVC_CONSOLES; i++) 881 if (vtermnos[i] == hp->vtermno && 882 cons_ops[i] == hp->ops) 883 break; 884 885 /* no matching slot, just use a counter */ 886 if (i >= MAX_NR_HVC_CONSOLES) 887 i = ++last_hvc; 888 889 hp->index = i; 890 cons_ops[i] = ops; 891 vtermnos[i] = vtermno; 892 893 list_add_tail(&(hp->next), &hvc_structs); 894 spin_unlock(&hvc_structs_lock); 895 896 /* check if we need to re-register the kernel console */ 897 hvc_check_console(i); 898 899 return hp; 900 } 901 EXPORT_SYMBOL_GPL(hvc_alloc); 902 903 int hvc_remove(struct hvc_struct *hp) 904 { 905 unsigned long flags; 906 struct tty_struct *tty; 907 908 tty = tty_port_tty_get(&hp->port); 909 910 console_lock(); 911 spin_lock_irqsave(&hp->lock, flags); 912 if (hp->index < MAX_NR_HVC_CONSOLES) { 913 vtermnos[hp->index] = -1; 914 cons_ops[hp->index] = NULL; 915 } 916 917 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ 918 919 spin_unlock_irqrestore(&hp->lock, flags); 920 console_unlock(); 921 922 /* 923 * We 'put' the instance that was grabbed when the kref instance 924 * was initialized using kref_init(). Let the last holder of this 925 * kref cause it to be removed, which will probably be the tty_vhangup 926 * below. 927 */ 928 tty_port_put(&hp->port); 929 930 /* 931 * This function call will auto chain call hvc_hangup. 932 */ 933 if (tty) { 934 tty_vhangup(tty); 935 tty_kref_put(tty); 936 } 937 return 0; 938 } 939 EXPORT_SYMBOL_GPL(hvc_remove); 940 941 /* Driver initialization: called as soon as someone uses hvc_alloc(). */ 942 static int hvc_init(void) 943 { 944 struct tty_driver *drv; 945 int err; 946 947 /* We need more than hvc_count adapters due to hotplug additions. */ 948 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); 949 if (!drv) { 950 err = -ENOMEM; 951 goto out; 952 } 953 954 drv->driver_name = "hvc"; 955 drv->name = "hvc"; 956 drv->major = HVC_MAJOR; 957 drv->minor_start = HVC_MINOR; 958 drv->type = TTY_DRIVER_TYPE_SYSTEM; 959 drv->init_termios = tty_std_termios; 960 drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS; 961 tty_set_operations(drv, &hvc_ops); 962 963 /* Always start the kthread because there can be hotplug vty adapters 964 * added later. */ 965 hvc_task = kthread_run(khvcd, NULL, "khvcd"); 966 if (IS_ERR(hvc_task)) { 967 printk(KERN_ERR "Couldn't create kthread for console.\n"); 968 err = PTR_ERR(hvc_task); 969 goto put_tty; 970 } 971 972 err = tty_register_driver(drv); 973 if (err) { 974 printk(KERN_ERR "Couldn't register hvc console driver\n"); 975 goto stop_thread; 976 } 977 978 /* 979 * Make sure tty is fully registered before allowing it to be 980 * found by hvc_console_device. 981 */ 982 smp_mb(); 983 hvc_driver = drv; 984 return 0; 985 986 stop_thread: 987 kthread_stop(hvc_task); 988 hvc_task = NULL; 989 put_tty: 990 put_tty_driver(drv); 991 out: 992 return err; 993 } 994