1/* 2 * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM 3 * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM 4 * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp. 5 * Copyright (C) 2004 IBM Corporation 6 * 7 * Additional Author(s): 8 * Ryan S. Arnold <rsa@us.ibm.com> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; either version 2 of the License, or 13 * (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 23 */ 24 25#include <linux/console.h> 26#include <linux/cpumask.h> 27#include <linux/init.h> 28#include <linux/kbd_kern.h> 29#include <linux/kernel.h> 30#include <linux/kthread.h> 31#include <linux/list.h> 32#include <linux/module.h> 33#include <linux/major.h> 34#include <linux/sysrq.h> 35#include <linux/tty.h> 36#include <linux/tty_flip.h> 37#include <linux/sched.h> 38#include <linux/spinlock.h> 39#include <linux/delay.h> 40#include <linux/freezer.h> 41#include <linux/slab.h> 42 43#include <asm/uaccess.h> 44 45#include "hvc_console.h" 46 47#define HVC_MAJOR 229 48#define HVC_MINOR 0 49 50/* 51 * Wait this long per iteration while trying to push buffered data to the 52 * hypervisor before allowing the tty to complete a close operation. 53 */ 54#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ 55 56/* 57 * These sizes are most efficient for vio, because they are the 58 * native transfer size. We could make them selectable in the 59 * future to better deal with backends that want other buffer sizes. 60 */ 61#define N_OUTBUF 16 62#define N_INBUF 16 63 64#define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) 65 66static struct tty_driver *hvc_driver; 67static struct task_struct *hvc_task; 68 69/* Picks up late kicks after list walk but before schedule() */ 70static int hvc_kicked; 71 72static int hvc_init(void); 73 74#ifdef CONFIG_MAGIC_SYSRQ 75static int sysrq_pressed; 76#endif 77 78/* dynamic list of hvc_struct instances */ 79static LIST_HEAD(hvc_structs); 80 81/* 82 * Protect the list of hvc_struct instances from inserts and removals during 83 * list traversal. 84 */ 85static DEFINE_SPINLOCK(hvc_structs_lock); 86 87/* 88 * This value is used to assign a tty->index value to a hvc_struct based 89 * upon order of exposure via hvc_probe(), when we can not match it to 90 * a console candidate registered with hvc_instantiate(). 91 */ 92static int last_hvc = -1; 93 94/* 95 * Do not call this function with either the hvc_structs_lock or the hvc_struct 96 * lock held. If successful, this function increments the kref reference 97 * count against the target hvc_struct so it should be released when finished. 98 */ 99static struct hvc_struct *hvc_get_by_index(int index) 100{ 101 struct hvc_struct *hp; 102 unsigned long flags; 103 104 spin_lock(&hvc_structs_lock); 105 106 list_for_each_entry(hp, &hvc_structs, next) { 107 spin_lock_irqsave(&hp->lock, flags); 108 if (hp->index == index) { 109 kref_get(&hp->kref); 110 spin_unlock_irqrestore(&hp->lock, flags); 111 spin_unlock(&hvc_structs_lock); 112 return hp; 113 } 114 spin_unlock_irqrestore(&hp->lock, flags); 115 } 116 hp = NULL; 117 118 spin_unlock(&hvc_structs_lock); 119 return hp; 120} 121 122 123/* 124 * Initial console vtermnos for console API usage prior to full console 125 * initialization. Any vty adapter outside this range will not have usable 126 * console interfaces but can still be used as a tty device. This has to be 127 * static because kmalloc will not work during early console init. 128 */ 129static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES]; 130static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] = 131 {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1}; 132 133/* 134 * Console APIs, NOT TTY. These APIs are available immediately when 135 * hvc_console_setup() finds adapters. 136 */ 137 138static void hvc_console_print(struct console *co, const char *b, 139 unsigned count) 140{ 141 char c[N_OUTBUF] __ALIGNED__; 142 unsigned i = 0, n = 0; 143 int r, donecr = 0, index = co->index; 144 145 /* Console access attempt outside of acceptable console range. */ 146 if (index >= MAX_NR_HVC_CONSOLES) 147 return; 148 149 /* This console adapter was removed so it is not usable. */ 150 if (vtermnos[index] == -1) 151 return; 152 153 while (count > 0 || i > 0) { 154 if (count > 0 && i < sizeof(c)) { 155 if (b[n] == '\n' && !donecr) { 156 c[i++] = '\r'; 157 donecr = 1; 158 } else { 159 c[i++] = b[n++]; 160 donecr = 0; 161 --count; 162 } 163 } else { 164 r = cons_ops[index]->put_chars(vtermnos[index], c, i); 165 if (r <= 0) { 166 /* throw away chars on error */ 167 i = 0; 168 } else if (r > 0) { 169 i -= r; 170 if (i > 0) 171 memmove(c, c+r, i); 172 } 173 } 174 } 175} 176 177static struct tty_driver *hvc_console_device(struct console *c, int *index) 178{ 179 if (vtermnos[c->index] == -1) 180 return NULL; 181 182 *index = c->index; 183 return hvc_driver; 184} 185 186static int __init hvc_console_setup(struct console *co, char *options) 187{ 188 if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES) 189 return -ENODEV; 190 191 if (vtermnos[co->index] == -1) 192 return -ENODEV; 193 194 return 0; 195} 196 197static struct console hvc_console = { 198 .name = "hvc", 199 .write = hvc_console_print, 200 .device = hvc_console_device, 201 .setup = hvc_console_setup, 202 .flags = CON_PRINTBUFFER, 203 .index = -1, 204}; 205 206/* 207 * Early console initialization. Precedes driver initialization. 208 * 209 * (1) we are first, and the user specified another driver 210 * -- index will remain -1 211 * (2) we are first and the user specified no driver 212 * -- index will be set to 0, then we will fail setup. 213 * (3) we are first and the user specified our driver 214 * -- index will be set to user specified driver, and we will fail 215 * (4) we are after driver, and this initcall will register us 216 * -- if the user didn't specify a driver then the console will match 217 * 218 * Note that for cases 2 and 3, we will match later when the io driver 219 * calls hvc_instantiate() and call register again. 220 */ 221static int __init hvc_console_init(void) 222{ 223 register_console(&hvc_console); 224 return 0; 225} 226console_initcall(hvc_console_init); 227 228/* callback when the kboject ref count reaches zero. */ 229static void destroy_hvc_struct(struct kref *kref) 230{ 231 struct hvc_struct *hp = container_of(kref, struct hvc_struct, kref); 232 unsigned long flags; 233 234 spin_lock(&hvc_structs_lock); 235 236 spin_lock_irqsave(&hp->lock, flags); 237 list_del(&(hp->next)); 238 spin_unlock_irqrestore(&hp->lock, flags); 239 240 spin_unlock(&hvc_structs_lock); 241 242 kfree(hp); 243} 244 245/* 246 * hvc_instantiate() is an early console discovery method which locates 247 * consoles * prior to the vio subsystem discovering them. Hotplugged 248 * vty adapters do NOT get an hvc_instantiate() callback since they 249 * appear after early console init. 250 */ 251int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops) 252{ 253 struct hvc_struct *hp; 254 255 if (index < 0 || index >= MAX_NR_HVC_CONSOLES) 256 return -1; 257 258 if (vtermnos[index] != -1) 259 return -1; 260 261 /* make sure no no tty has been registered in this index */ 262 hp = hvc_get_by_index(index); 263 if (hp) { 264 kref_put(&hp->kref, destroy_hvc_struct); 265 return -1; 266 } 267 268 vtermnos[index] = vtermno; 269 cons_ops[index] = ops; 270 271 /* reserve all indices up to and including this index */ 272 if (last_hvc < index) 273 last_hvc = index; 274 275 /* if this index is what the user requested, then register 276 * now (setup won't fail at this point). It's ok to just 277 * call register again if previously .setup failed. 278 */ 279 if (index == hvc_console.index) 280 register_console(&hvc_console); 281 282 return 0; 283} 284EXPORT_SYMBOL_GPL(hvc_instantiate); 285 286/* Wake the sleeping khvcd */ 287void hvc_kick(void) 288{ 289 hvc_kicked = 1; 290 wake_up_process(hvc_task); 291} 292EXPORT_SYMBOL_GPL(hvc_kick); 293 294static void hvc_unthrottle(struct tty_struct *tty) 295{ 296 hvc_kick(); 297} 298 299/* 300 * The TTY interface won't be used until after the vio layer has exposed the vty 301 * adapter to the kernel. 302 */ 303static int hvc_open(struct tty_struct *tty, struct file * filp) 304{ 305 struct hvc_struct *hp; 306 unsigned long flags; 307 int rc = 0; 308 309 /* Auto increments kref reference if found. */ 310 if (!(hp = hvc_get_by_index(tty->index))) 311 return -ENODEV; 312 313 spin_lock_irqsave(&hp->lock, flags); 314 /* Check and then increment for fast path open. */ 315 if (hp->count++ > 0) { 316 tty_kref_get(tty); 317 spin_unlock_irqrestore(&hp->lock, flags); 318 hvc_kick(); 319 return 0; 320 } /* else count == 0 */ 321 322 tty->driver_data = hp; 323 324 hp->tty = tty_kref_get(tty); 325 326 spin_unlock_irqrestore(&hp->lock, flags); 327 328 if (hp->ops->notifier_add) 329 rc = hp->ops->notifier_add(hp, hp->data); 330 331 /* 332 * If the notifier fails we return an error. The tty layer 333 * will call hvc_close() after a failed open but we don't want to clean 334 * up there so we'll clean up here and clear out the previously set 335 * tty fields and return the kref reference. 336 */ 337 if (rc) { 338 spin_lock_irqsave(&hp->lock, flags); 339 hp->tty = NULL; 340 spin_unlock_irqrestore(&hp->lock, flags); 341 tty_kref_put(tty); 342 tty->driver_data = NULL; 343 kref_put(&hp->kref, destroy_hvc_struct); 344 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); 345 } 346 /* Force wakeup of the polling thread */ 347 hvc_kick(); 348 349 return rc; 350} 351 352static void hvc_close(struct tty_struct *tty, struct file * filp) 353{ 354 struct hvc_struct *hp; 355 unsigned long flags; 356 357 if (tty_hung_up_p(filp)) 358 return; 359 360 /* 361 * No driver_data means that this close was issued after a failed 362 * hvc_open by the tty layer's release_dev() function and we can just 363 * exit cleanly because the kref reference wasn't made. 364 */ 365 if (!tty->driver_data) 366 return; 367 368 hp = tty->driver_data; 369 370 spin_lock_irqsave(&hp->lock, flags); 371 372 if (--hp->count == 0) { 373 /* We are done with the tty pointer now. */ 374 hp->tty = NULL; 375 spin_unlock_irqrestore(&hp->lock, flags); 376 377 if (hp->ops->notifier_del) 378 hp->ops->notifier_del(hp, hp->data); 379 380 /* cancel pending tty resize work */ 381 cancel_work_sync(&hp->tty_resize); 382 383 /* 384 * Chain calls chars_in_buffer() and returns immediately if 385 * there is no buffered data otherwise sleeps on a wait queue 386 * waking periodically to check chars_in_buffer(). 387 */ 388 tty_wait_until_sent(tty, HVC_CLOSE_WAIT); 389 } else { 390 if (hp->count < 0) 391 printk(KERN_ERR "hvc_close %X: oops, count is %d\n", 392 hp->vtermno, hp->count); 393 spin_unlock_irqrestore(&hp->lock, flags); 394 } 395 396 tty_kref_put(tty); 397 kref_put(&hp->kref, destroy_hvc_struct); 398} 399 400static void hvc_hangup(struct tty_struct *tty) 401{ 402 struct hvc_struct *hp = tty->driver_data; 403 unsigned long flags; 404 int temp_open_count; 405 406 if (!hp) 407 return; 408 409 /* cancel pending tty resize work */ 410 cancel_work_sync(&hp->tty_resize); 411 412 spin_lock_irqsave(&hp->lock, flags); 413 414 /* 415 * The N_TTY line discipline has problems such that in a close vs 416 * open->hangup case this can be called after the final close so prevent 417 * that from happening for now. 418 */ 419 if (hp->count <= 0) { 420 spin_unlock_irqrestore(&hp->lock, flags); 421 return; 422 } 423 424 temp_open_count = hp->count; 425 hp->count = 0; 426 hp->n_outbuf = 0; 427 hp->tty = NULL; 428 429 spin_unlock_irqrestore(&hp->lock, flags); 430 431 if (hp->ops->notifier_hangup) 432 hp->ops->notifier_hangup(hp, hp->data); 433 434 while(temp_open_count) { 435 --temp_open_count; 436 tty_kref_put(tty); 437 kref_put(&hp->kref, destroy_hvc_struct); 438 } 439} 440 441/* 442 * Push buffered characters whether they were just recently buffered or waiting 443 * on a blocked hypervisor. Call this function with hp->lock held. 444 */ 445static int hvc_push(struct hvc_struct *hp) 446{ 447 int n; 448 449 n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); 450 if (n <= 0) { 451 if (n == 0) { 452 hp->do_wakeup = 1; 453 return 0; 454 } 455 /* throw away output on error; this happens when 456 there is no session connected to the vterm. */ 457 hp->n_outbuf = 0; 458 } else 459 hp->n_outbuf -= n; 460 if (hp->n_outbuf > 0) 461 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); 462 else 463 hp->do_wakeup = 1; 464 465 return n; 466} 467 468static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) 469{ 470 struct hvc_struct *hp = tty->driver_data; 471 unsigned long flags; 472 int rsize, written = 0; 473 474 /* This write was probably executed during a tty close. */ 475 if (!hp) 476 return -EPIPE; 477 478 if (hp->count <= 0) 479 return -EIO; 480 481 spin_lock_irqsave(&hp->lock, flags); 482 483 /* Push pending writes */ 484 if (hp->n_outbuf > 0) 485 hvc_push(hp); 486 487 while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) { 488 if (rsize > count) 489 rsize = count; 490 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); 491 count -= rsize; 492 buf += rsize; 493 hp->n_outbuf += rsize; 494 written += rsize; 495 hvc_push(hp); 496 } 497 spin_unlock_irqrestore(&hp->lock, flags); 498 499 /* 500 * Racy, but harmless, kick thread if there is still pending data. 501 */ 502 if (hp->n_outbuf) 503 hvc_kick(); 504 505 return written; 506} 507 508/** 509 * hvc_set_winsz() - Resize the hvc tty terminal window. 510 * @work: work structure. 511 * 512 * The routine shall not be called within an atomic context because it 513 * might sleep. 514 * 515 * Locking: hp->lock 516 */ 517static void hvc_set_winsz(struct work_struct *work) 518{ 519 struct hvc_struct *hp; 520 unsigned long hvc_flags; 521 struct tty_struct *tty; 522 struct winsize ws; 523 524 hp = container_of(work, struct hvc_struct, tty_resize); 525 526 spin_lock_irqsave(&hp->lock, hvc_flags); 527 if (!hp->tty) { 528 spin_unlock_irqrestore(&hp->lock, hvc_flags); 529 return; 530 } 531 ws = hp->ws; 532 tty = tty_kref_get(hp->tty); 533 spin_unlock_irqrestore(&hp->lock, hvc_flags); 534 535 tty_do_resize(tty, &ws); 536 tty_kref_put(tty); 537} 538 539/* 540 * This is actually a contract between the driver and the tty layer outlining 541 * how much write room the driver can guarantee will be sent OR BUFFERED. This 542 * driver MUST honor the return value. 543 */ 544static int hvc_write_room(struct tty_struct *tty) 545{ 546 struct hvc_struct *hp = tty->driver_data; 547 548 if (!hp) 549 return -1; 550 551 return hp->outbuf_size - hp->n_outbuf; 552} 553 554static int hvc_chars_in_buffer(struct tty_struct *tty) 555{ 556 struct hvc_struct *hp = tty->driver_data; 557 558 if (!hp) 559 return 0; 560 return hp->n_outbuf; 561} 562 563/* 564 * timeout will vary between the MIN and MAX values defined here. By default 565 * and during console activity we will use a default MIN_TIMEOUT of 10. When 566 * the console is idle, we increase the timeout value on each pass through 567 * msleep until we reach the max. This may be noticeable as a brief (average 568 * one second) delay on the console before the console responds to input when 569 * there has been no input for some time. 570 */ 571#define MIN_TIMEOUT (10) 572#define MAX_TIMEOUT (2000) 573static u32 timeout = MIN_TIMEOUT; 574 575#define HVC_POLL_READ 0x00000001 576#define HVC_POLL_WRITE 0x00000002 577 578int hvc_poll(struct hvc_struct *hp) 579{ 580 struct tty_struct *tty; 581 int i, n, poll_mask = 0; 582 char buf[N_INBUF] __ALIGNED__; 583 unsigned long flags; 584 int read_total = 0; 585 int written_total = 0; 586 587 spin_lock_irqsave(&hp->lock, flags); 588 589 /* Push pending writes */ 590 if (hp->n_outbuf > 0) 591 written_total = hvc_push(hp); 592 593 /* Reschedule us if still some write pending */ 594 if (hp->n_outbuf > 0) { 595 poll_mask |= HVC_POLL_WRITE; 596 /* If hvc_push() was not able to write, sleep a few msecs */ 597 timeout = (written_total) ? 0 : MIN_TIMEOUT; 598 } 599 600 /* No tty attached, just skip */ 601 tty = tty_kref_get(hp->tty); 602 if (tty == NULL) 603 goto bail; 604 605 /* Now check if we can get data (are we throttled ?) */ 606 if (test_bit(TTY_THROTTLED, &tty->flags)) 607 goto throttled; 608 609 /* If we aren't notifier driven and aren't throttled, we always 610 * request a reschedule 611 */ 612 if (!hp->irq_requested) 613 poll_mask |= HVC_POLL_READ; 614 615 /* Read data if any */ 616 for (;;) { 617 int count = tty_buffer_request_room(tty, N_INBUF); 618 619 /* If flip is full, just reschedule a later read */ 620 if (count == 0) { 621 poll_mask |= HVC_POLL_READ; 622 break; 623 } 624 625 n = hp->ops->get_chars(hp->vtermno, buf, count); 626 if (n <= 0) { 627 /* Hangup the tty when disconnected from host */ 628 if (n == -EPIPE) { 629 spin_unlock_irqrestore(&hp->lock, flags); 630 tty_hangup(tty); 631 spin_lock_irqsave(&hp->lock, flags); 632 } else if ( n == -EAGAIN ) { 633 /* 634 * Some back-ends can only ensure a certain min 635 * num of bytes read, which may be > 'count'. 636 * Let the tty clear the flip buff to make room. 637 */ 638 poll_mask |= HVC_POLL_READ; 639 } 640 break; 641 } 642 for (i = 0; i < n; ++i) { 643#ifdef CONFIG_MAGIC_SYSRQ 644 if (hp->index == hvc_console.index) { 645 /* Handle the SysRq Hack */ 646 if (buf[i] == '\x0f') { /* ^O */ 647 /* if ^O is pressed again, reset 648 * sysrq_pressed and flip ^O char */ 649 sysrq_pressed = !sysrq_pressed; 650 if (sysrq_pressed) 651 continue; 652 } else if (sysrq_pressed) { 653 handle_sysrq(buf[i]); 654 sysrq_pressed = 0; 655 continue; 656 } 657 } 658#endif /* CONFIG_MAGIC_SYSRQ */ 659 tty_insert_flip_char(tty, buf[i], 0); 660 } 661 662 read_total += n; 663 } 664 throttled: 665 /* Wakeup write queue if necessary */ 666 if (hp->do_wakeup) { 667 hp->do_wakeup = 0; 668 tty_wakeup(tty); 669 } 670 bail: 671 spin_unlock_irqrestore(&hp->lock, flags); 672 673 if (read_total) { 674 /* Activity is occurring, so reset the polling backoff value to 675 a minimum for performance. */ 676 timeout = MIN_TIMEOUT; 677 678 tty_flip_buffer_push(tty); 679 } 680 if (tty) 681 tty_kref_put(tty); 682 683 return poll_mask; 684} 685EXPORT_SYMBOL_GPL(hvc_poll); 686 687/** 688 * __hvc_resize() - Update terminal window size information. 689 * @hp: HVC console pointer 690 * @ws: Terminal window size structure 691 * 692 * Stores the specified window size information in the hvc structure of @hp. 693 * The function schedule the tty resize update. 694 * 695 * Locking: Locking free; the function MUST be called holding hp->lock 696 */ 697void __hvc_resize(struct hvc_struct *hp, struct winsize ws) 698{ 699 hp->ws = ws; 700 schedule_work(&hp->tty_resize); 701} 702EXPORT_SYMBOL_GPL(__hvc_resize); 703 704/* 705 * This kthread is either polling or interrupt driven. This is determined by 706 * calling hvc_poll() who determines whether a console adapter support 707 * interrupts. 708 */ 709static int khvcd(void *unused) 710{ 711 int poll_mask; 712 struct hvc_struct *hp; 713 714 set_freezable(); 715 __set_current_state(TASK_RUNNING); 716 do { 717 poll_mask = 0; 718 hvc_kicked = 0; 719 try_to_freeze(); 720 wmb(); 721 if (!cpus_are_in_xmon()) { 722 spin_lock(&hvc_structs_lock); 723 list_for_each_entry(hp, &hvc_structs, next) { 724 poll_mask |= hvc_poll(hp); 725 } 726 spin_unlock(&hvc_structs_lock); 727 } else 728 poll_mask |= HVC_POLL_READ; 729 if (hvc_kicked) 730 continue; 731 set_current_state(TASK_INTERRUPTIBLE); 732 if (!hvc_kicked) { 733 if (poll_mask == 0) 734 schedule(); 735 else { 736 if (timeout < MAX_TIMEOUT) 737 timeout += (timeout >> 6) + 1; 738 739 msleep_interruptible(timeout); 740 } 741 } 742 __set_current_state(TASK_RUNNING); 743 } while (!kthread_should_stop()); 744 745 return 0; 746} 747 748static const struct tty_operations hvc_ops = { 749 .open = hvc_open, 750 .close = hvc_close, 751 .write = hvc_write, 752 .hangup = hvc_hangup, 753 .unthrottle = hvc_unthrottle, 754 .write_room = hvc_write_room, 755 .chars_in_buffer = hvc_chars_in_buffer, 756}; 757 758struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, 759 const struct hv_ops *ops, 760 int outbuf_size) 761{ 762 struct hvc_struct *hp; 763 int i; 764 765 /* We wait until a driver actually comes along */ 766 if (!hvc_driver) { 767 int err = hvc_init(); 768 if (err) 769 return ERR_PTR(err); 770 } 771 772 hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, 773 GFP_KERNEL); 774 if (!hp) 775 return ERR_PTR(-ENOMEM); 776 777 hp->vtermno = vtermno; 778 hp->data = data; 779 hp->ops = ops; 780 hp->outbuf_size = outbuf_size; 781 hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; 782 783 kref_init(&hp->kref); 784 785 INIT_WORK(&hp->tty_resize, hvc_set_winsz); 786 spin_lock_init(&hp->lock); 787 spin_lock(&hvc_structs_lock); 788 789 /* 790 * find index to use: 791 * see if this vterm id matches one registered for console. 792 */ 793 for (i=0; i < MAX_NR_HVC_CONSOLES; i++) 794 if (vtermnos[i] == hp->vtermno && 795 cons_ops[i] == hp->ops) 796 break; 797 798 /* no matching slot, just use a counter */ 799 if (i >= MAX_NR_HVC_CONSOLES) 800 i = ++last_hvc; 801 802 hp->index = i; 803 804 list_add_tail(&(hp->next), &hvc_structs); 805 spin_unlock(&hvc_structs_lock); 806 807 return hp; 808} 809EXPORT_SYMBOL_GPL(hvc_alloc); 810 811int hvc_remove(struct hvc_struct *hp) 812{ 813 unsigned long flags; 814 struct tty_struct *tty; 815 816 spin_lock_irqsave(&hp->lock, flags); 817 tty = tty_kref_get(hp->tty); 818 819 if (hp->index < MAX_NR_HVC_CONSOLES) 820 vtermnos[hp->index] = -1; 821 822 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ 823 824 spin_unlock_irqrestore(&hp->lock, flags); 825 826 /* 827 * We 'put' the instance that was grabbed when the kref instance 828 * was initialized using kref_init(). Let the last holder of this 829 * kref cause it to be removed, which will probably be the tty_vhangup 830 * below. 831 */ 832 kref_put(&hp->kref, destroy_hvc_struct); 833 834 /* 835 * This function call will auto chain call hvc_hangup. 836 */ 837 if (tty) { 838 tty_vhangup(tty); 839 tty_kref_put(tty); 840 } 841 return 0; 842} 843EXPORT_SYMBOL_GPL(hvc_remove); 844 845/* Driver initialization: called as soon as someone uses hvc_alloc(). */ 846static int hvc_init(void) 847{ 848 struct tty_driver *drv; 849 int err; 850 851 /* We need more than hvc_count adapters due to hotplug additions. */ 852 drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); 853 if (!drv) { 854 err = -ENOMEM; 855 goto out; 856 } 857 858 drv->owner = THIS_MODULE; 859 drv->driver_name = "hvc"; 860 drv->name = "hvc"; 861 drv->major = HVC_MAJOR; 862 drv->minor_start = HVC_MINOR; 863 drv->type = TTY_DRIVER_TYPE_SYSTEM; 864 drv->init_termios = tty_std_termios; 865 drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS; 866 tty_set_operations(drv, &hvc_ops); 867 868 /* Always start the kthread because there can be hotplug vty adapters 869 * added later. */ 870 hvc_task = kthread_run(khvcd, NULL, "khvcd"); 871 if (IS_ERR(hvc_task)) { 872 printk(KERN_ERR "Couldn't create kthread for console.\n"); 873 err = PTR_ERR(hvc_task); 874 goto put_tty; 875 } 876 877 err = tty_register_driver(drv); 878 if (err) { 879 printk(KERN_ERR "Couldn't register hvc console driver\n"); 880 goto stop_thread; 881 } 882 883 /* 884 * Make sure tty is fully registered before allowing it to be 885 * found by hvc_console_device. 886 */ 887 smp_mb(); 888 hvc_driver = drv; 889 return 0; 890 891stop_thread: 892 kthread_stop(hvc_task); 893 hvc_task = NULL; 894put_tty: 895 put_tty_driver(drv); 896out: 897 return err; 898} 899 900/* This isn't particularly necessary due to this being a console driver 901 * but it is nice to be thorough. 902 */ 903static void __exit hvc_exit(void) 904{ 905 if (hvc_driver) { 906 kthread_stop(hvc_task); 907 908 tty_unregister_driver(hvc_driver); 909 /* return tty_struct instances allocated in hvc_init(). */ 910 put_tty_driver(hvc_driver); 911 unregister_console(&hvc_console); 912 } 913} 914module_exit(hvc_exit); 915