drivers/char/hvc_console.c

   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/kobject.h>
  31 #include <linux/kthread.h>
  32 #include <linux/list.h>
  33 #include <linux/module.h>
  34 #include <linux/major.h>
  35 #include <linux/sysrq.h>
  36 #include <linux/tty.h>
  37 #include <linux/tty_flip.h>
  38 #include <linux/sched.h>
  39 #include <linux/spinlock.h>
  40 #include <linux/delay.h>
  41 #include <asm/uaccess.h>
  42 #include <asm/hvconsole.h>
  43 #include <asm/vio.h>
  44
  45 #define HVC_MAJOR       229
  46 #define HVC_MINOR       0
  47
  48 #define TIMEOUT         (10)
  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  * The Linux TTY code does not support dynamic addition of tty derived devices
  58  * so we need to know how many tty devices we might need when space is allocated
  59  * for the tty device.  Since this driver supports hotplug of vty adapters we
  60  * need to make sure we have enough allocated.
  61  */
  62 #define HVC_ALLOC_TTY_ADAPTERS  8
  63
  64 #define N_OUTBUF        16
  65 #define N_INBUF         16
  66
  67 #define __ALIGNED__     __attribute__((__aligned__(8)))
  68
  69 static struct tty_driver *hvc_driver;
  70 static struct task_struct *hvc_task;
  71
  72 /* Picks up late kicks after list walk but before schedule() */
  73 static int hvc_kicked;
  74
  75 #ifdef CONFIG_MAGIC_SYSRQ
  76 static int sysrq_pressed;
  77 #endif
  78
  79 struct hvc_struct {
  80         spinlock_t lock;
  81         int index;
  82         struct tty_struct *tty;
  83         unsigned int count;
  84         int do_wakeup;
  85         char outbuf[N_OUTBUF] __ALIGNED__;
  86         int n_outbuf;
  87         uint32_t vtermno;
  88         int irq_requested;
  89         int irq;
  90         struct list_head next;
  91         struct kobject kobj; /* ref count & hvc_struct lifetime */
  92         struct vio_dev *vdev;
  93 };
  94
  95 /* dynamic list of hvc_struct instances */
  96 static struct list_head hvc_structs = LIST_HEAD_INIT(hvc_structs);
  97
  98 /*
  99  * Protect the list of hvc_struct instances from inserts and removals during
 100  * list traversal.
 101  */
 102 static DEFINE_SPINLOCK(hvc_structs_lock);
 103
 104 /*
 105  * This value is used to associate a tty->index value to a hvc_struct based
 106  * upon order of exposure via hvc_probe().
 107  */
 108 static int hvc_count = -1;
 109
 110 /*
 111  * Do not call this function with either the hvc_strucst_lock or the hvc_struct
 112  * lock held.  If successful, this function increments the kobject reference
 113  * count against the target hvc_struct so it should be released when finished.
 114  */
 115 struct hvc_struct *hvc_get_by_index(int index)
 116 {
 117         struct hvc_struct *hp;
 118         unsigned long flags;
 119
 120         spin_lock(&hvc_structs_lock);
 121
 122         list_for_each_entry(hp, &hvc_structs, next) {
 123                 spin_lock_irqsave(&hp->lock, flags);
 124                 if (hp->index == index) {
 125                         kobject_get(&hp->kobj);
 126                         spin_unlock_irqrestore(&hp->lock, flags);
 127                         spin_unlock(&hvc_structs_lock);
 128                         return hp;
 129                 }
 130                 spin_unlock_irqrestore(&hp->lock, flags);
 131         }
 132         hp = NULL;
 133
 134         spin_unlock(&hvc_structs_lock);
 135         return hp;
 136 }
 137
 138
 139 /*
 140  * Initial console vtermnos for console API usage prior to full console
 141  * initialization.  Any vty adapter outside this range will not have usable
 142  * console interfaces but can still be used as a tty device.  This has to be
 143  * static because kmalloc will not work during early console init.
 144  */
 145 static uint32_t vtermnos[MAX_NR_HVC_CONSOLES];
 146
 147 /* Used for accounting purposes */
 148 static int num_vterms = 0;
 149
 150 /*
 151  * Console APIs, NOT TTY.  These APIs are available immediately when
 152  * hvc_console_setup() finds adapters.
 153  */
 154
 155 void hvc_console_print(struct console *co, const char *b, unsigned count)
 156 {
 157         char c[16] __ALIGNED__;
 158         unsigned i = 0, n = 0;
 159         int r, donecr = 0;
 160
 161         /* Console access attempt outside of acceptable console range. */
 162         if (co->index >= MAX_NR_HVC_CONSOLES)
 163                 return;
 164
 165         /* This console adapter was removed so it is not useable. */
 166         if (vtermnos[co->index] < 0)
 167                 return;
 168
 169         while (count > 0 || i > 0) {
 170                 if (count > 0 && i < sizeof(c)) {
 171                         if (b[n] == '\n' && !donecr) {
 172                                 c[i++] = '\r';
 173                                 donecr = 1;
 174                         } else {
 175                                 c[i++] = b[n++];
 176                                 donecr = 0;
 177                                 --count;
 178                         }
 179                 } else {
 180                         r = hvc_put_chars(vtermnos[co->index], c, i);
 181                         if (r < 0) {
 182                                 /* throw away chars on error */
 183                                 i = 0;
 184                         } else if (r > 0) {
 185                                 i -= r;
 186                                 if (i > 0)
 187                                         memmove(c, c+r, i);
 188                         }
 189                 }
 190         }
 191 }
 192
 193 static struct tty_driver *hvc_console_device(struct console *c, int *index)
 194 {
 195         *index = c->index;
 196         return hvc_driver;
 197 }
 198
 199 static int __init hvc_console_setup(struct console *co, char *options)
 200 {
 201         return 0;
 202 }
 203
 204 struct console hvc_con_driver = {
 205         .name           = "hvc",
 206         .write          = hvc_console_print,
 207         .device         = hvc_console_device,
 208         .setup          = hvc_console_setup,
 209         .flags          = CON_PRINTBUFFER,
 210         .index          = -1,
 211 };
 212
 213 /* Early console initialization.  Preceeds driver initialization. */
 214 static int __init hvc_console_init(void)
 215 {
 216         int i;
 217
 218         for (i=0; i<MAX_NR_HVC_CONSOLES; i++)
 219                 vtermnos[i] = -1;
 220         num_vterms = hvc_find_vtys();
 221         register_console(&hvc_con_driver);
 222         return 0;
 223 }
 224 console_initcall(hvc_console_init);
 225
 226 /*
 227  * hvc_instantiate() is an early console discovery method which locates consoles
 228  * prior to the vio subsystem discovering them.  Hotplugged vty adapters do NOT
 229  * get an hvc_instantiate() callback since the appear after early console init.
 230  */
 231 int hvc_instantiate(uint32_t vtermno, int index)
 232 {
 233         if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
 234                 return -1;
 235
 236         if (vtermnos[index] != -1)
 237                 return -1;
 238
 239         vtermnos[index] = vtermno;
 240         return 0;
 241 }
 242
 243 /* Wake the sleeping khvcd */
 244 static void hvc_kick(void)
 245 {
 246         hvc_kicked = 1;
 247         wake_up_process(hvc_task);
 248 }
 249
 250 /*
 251  * NOTE: This API isn't used if the console adapter doesn't support interrupts.
 252  * In this case the console is poll driven.
 253  */
 254 static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
 255 {
 256         hvc_kick();
 257         return IRQ_HANDLED;
 258 }
 259
 260 static void hvc_unthrottle(struct tty_struct *tty)
 261 {
 262         hvc_kick();
 263 }
 264
 265 /*
 266  * The TTY interface won't be used until after the vio layer has exposed the vty
 267  * adapter to the kernel.
 268  */
 269 static int hvc_open(struct tty_struct *tty, struct file * filp)
 270 {
 271         struct hvc_struct *hp;
 272         unsigned long flags;
 273         int irq = NO_IRQ;
 274         int rc = 0;
 275         struct kobject *kobjp;
 276
 277         /* Auto increments kobject reference if found. */
 278         if (!(hp = hvc_get_by_index(tty->index))) {
 279                 printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n");
 280                 return -ENODEV;
 281         }
 282
 283         spin_lock_irqsave(&hp->lock, flags);
 284         /* Check and then increment for fast path open. */
 285         if (hp->count++ > 0) {
 286                 spin_unlock_irqrestore(&hp->lock, flags);
 287                 hvc_kick();
 288                 return 0;
 289         } /* else count == 0 */
 290
 291         tty->driver_data = hp;
 292         hp->tty = tty;
 293         /* Save for request_irq outside of spin_lock. */
 294         irq = hp->irq;
 295         if (irq != NO_IRQ)
 296                 hp->irq_requested = 1;
 297
 298         kobjp = &hp->kobj;
 299
 300         spin_unlock_irqrestore(&hp->lock, flags);
 301         /* check error, fallback to non-irq */
 302         if (irq != NO_IRQ)
 303                 rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp);
 304
 305         /*
 306          * If the request_irq() fails and we return an error.  The tty layer
 307          * will call hvc_close() after a failed open but we don't want to clean
 308          * up there so we'll clean up here and clear out the previously set
 309          * tty fields and return the kobject reference.
 310          */
 311         if (rc) {
 312                 spin_lock_irqsave(&hp->lock, flags);
 313                 hp->tty = NULL;
 314                 hp->irq_requested = 0;
 315                 spin_unlock_irqrestore(&hp->lock, flags);
 316                 tty->driver_data = NULL;
 317                 kobject_put(kobjp);
 318                 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
 319         }
 320         /* Force wakeup of the polling thread */
 321         hvc_kick();
 322
 323         return rc;
 324 }
 325
 326 static void hvc_close(struct tty_struct *tty, struct file * filp)
 327 {
 328         struct hvc_struct *hp;
 329         struct kobject *kobjp;
 330         int irq = NO_IRQ;
 331         unsigned long flags;
 332
 333         if (tty_hung_up_p(filp))
 334                 return;
 335
 336         /*
 337          * No driver_data means that this close was issued after a failed
 338          * hvc_open by the tty layer's release_dev() function and we can just
 339          * exit cleanly because the kobject reference wasn't made.
 340          */
 341         if (!tty->driver_data)
 342                 return;
 343
 344         hp = tty->driver_data;
 345         spin_lock_irqsave(&hp->lock, flags);
 346
 347         kobjp = &hp->kobj;
 348         if (--hp->count == 0) {
 349                 if (hp->irq_requested)
 350                         irq = hp->irq;
 351                 hp->irq_requested = 0;
 352
 353                 /* We are done with the tty pointer now. */
 354                 hp->tty = NULL;
 355                 spin_unlock_irqrestore(&hp->lock, flags);
 356
 357                 /*
 358                  * Chain calls chars_in_buffer() and returns immediately if
 359                  * there is no buffered data otherwise sleeps on a wait queue
 360                  * waking periodically to check chars_in_buffer().
 361                  */
 362                 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
 363
 364                 if (irq != NO_IRQ)
 365                         free_irq(irq, hp);
 366
 367         } else {
 368                 if (hp->count < 0)
 369                         printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
 370                                 hp->vtermno, hp->count);
 371                 spin_unlock_irqrestore(&hp->lock, flags);
 372         }
 373
 374         kobject_put(kobjp);
 375 }
 376
 377 static void hvc_hangup(struct tty_struct *tty)
 378 {
 379         struct hvc_struct *hp = tty->driver_data;
 380         unsigned long flags;
 381         int irq = NO_IRQ;
 382         int temp_open_count;
 383         struct kobject *kobjp;
 384
 385         if (!hp)
 386                 return;
 387
 388         spin_lock_irqsave(&hp->lock, flags);
 389
 390         /*
 391          * The N_TTY line discipline has problems such that in a close vs
 392          * open->hangup case this can be called after the final close so prevent
 393          * that from happening for now.
 394          */
 395         if (hp->count <= 0) {
 396                 spin_unlock_irqrestore(&hp->lock, flags);
 397                 return;
 398         }
 399
 400         kobjp = &hp->kobj;
 401         temp_open_count = hp->count;
 402         hp->count = 0;
 403         hp->n_outbuf = 0;
 404         hp->tty = NULL;
 405         if (hp->irq_requested)
 406                 /* Saved for use outside of spin_lock. */
 407                 irq = hp->irq;
 408         hp->irq_requested = 0;
 409         spin_unlock_irqrestore(&hp->lock, flags);
 410         if (irq != NO_IRQ)
 411                 free_irq(irq, hp);
 412         while(temp_open_count) {
 413                 --temp_open_count;
 414                 kobject_put(kobjp);
 415         }
 416 }
 417
 418 /*
 419  * Push buffered characters whether they were just recently buffered or waiting
 420  * on a blocked hypervisor.  Call this function with hp->lock held.
 421  */
 422 static void hvc_push(struct hvc_struct *hp)
 423 {
 424         int n;
 425
 426         n = hvc_put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
 427         if (n <= 0) {
 428                 if (n == 0)
 429                         return;
 430                 /* throw away output on error; this happens when
 431                    there is no session connected to the vterm. */
 432                 hp->n_outbuf = 0;
 433         } else
 434                 hp->n_outbuf -= n;
 435         if (hp->n_outbuf > 0)
 436                 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
 437         else
 438                 hp->do_wakeup = 1;
 439 }
 440
 441 static inline int __hvc_write_kernel(struct hvc_struct *hp,
 442                                    const unsigned char *buf, int count)
 443 {
 444         unsigned long flags;
 445         int rsize, written = 0;
 446
 447         spin_lock_irqsave(&hp->lock, flags);
 448
 449         /* Push pending writes */
 450         if (hp->n_outbuf > 0)
 451                 hvc_push(hp);
 452
 453         while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) {
 454                 if (rsize > count)
 455                         rsize = count;
 456                 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
 457                 count -= rsize;
 458                 buf += rsize;
 459                 hp->n_outbuf += rsize;
 460                 written += rsize;
 461                 hvc_push(hp);
 462         }
 463         spin_unlock_irqrestore(&hp->lock, flags);
 464
 465         return written;
 466 }
 467 static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
 468 {
 469         struct hvc_struct *hp = tty->driver_data;
 470         int written;
 471
 472         /* This write was probably executed during a tty close. */
 473         if (!hp)
 474                 return -EPIPE;
 475
 476         if (hp->count <= 0)
 477                 return -EIO;
 478
 479         written = __hvc_write_kernel(hp, buf, count);
 480
 481         /*
 482          * Racy, but harmless, kick thread if there is still pending data.
 483          * There really is nothing wrong with kicking the thread, even if there
 484          * is no buffered data.
 485          */
 486         if (hp->n_outbuf)
 487                 hvc_kick();
 488
 489         return written;
 490 }
 491
 492 /*
 493  * This is actually a contract between the driver and the tty layer outlining
 494  * how much write room the driver can guarentee will be sent OR BUFFERED.  This
 495  * driver MUST honor the return value.
 496  */
 497 static int hvc_write_room(struct tty_struct *tty)
 498 {
 499         struct hvc_struct *hp = tty->driver_data;
 500
 501         if (!hp)
 502                 return -1;
 503
 504         return N_OUTBUF - hp->n_outbuf;
 505 }
 506
 507 static int hvc_chars_in_buffer(struct tty_struct *tty)
 508 {
 509         struct hvc_struct *hp = tty->driver_data;
 510
 511         if (!hp)
 512                 return -1;
 513         return hp->n_outbuf;
 514 }
 515
 516 #define HVC_POLL_READ   0x00000001
 517 #define HVC_POLL_WRITE  0x00000002
 518 #define HVC_POLL_QUICK  0x00000004
 519
 520 static int hvc_poll(struct hvc_struct *hp)
 521 {
 522         struct tty_struct *tty;
 523         int i, n, poll_mask = 0;
 524         char buf[N_INBUF] __ALIGNED__;
 525         unsigned long flags;
 526         int read_total = 0;
 527
 528         spin_lock_irqsave(&hp->lock, flags);
 529
 530         /* Push pending writes */
 531         if (hp->n_outbuf > 0)
 532                 hvc_push(hp);
 533         /* Reschedule us if still some write pending */
 534         if (hp->n_outbuf > 0)
 535                 poll_mask |= HVC_POLL_WRITE;
 536
 537         /* No tty attached, just skip */
 538         tty = hp->tty;
 539         if (tty == NULL)
 540                 goto bail;
 541
 542         /* Now check if we can get data (are we throttled ?) */
 543         if (test_bit(TTY_THROTTLED, &tty->flags))
 544                 goto throttled;
 545
 546         /* If we aren't interrupt driven and aren't throttled, we always
 547          * request a reschedule
 548          */
 549         if (hp->irq == NO_IRQ)
 550                 poll_mask |= HVC_POLL_READ;
 551
 552         /* Read data if any */
 553         for (;;) {
 554                 int count = N_INBUF;
 555                 if (count > (TTY_FLIPBUF_SIZE - tty->flip.count))
 556                         count = TTY_FLIPBUF_SIZE - tty->flip.count;
 557
 558                 /* If flip is full, just reschedule a later read */
 559                 if (count == 0) {
 560                         poll_mask |= HVC_POLL_READ;
 561                         break;
 562                 }
 563
 564                 n = hvc_get_chars(hp->vtermno, buf, count);
 565                 if (n <= 0) {
 566                         /* Hangup the tty when disconnected from host */
 567                         if (n == -EPIPE) {
 568                                 spin_unlock_irqrestore(&hp->lock, flags);
 569                                 tty_hangup(tty);
 570                                 spin_lock_irqsave(&hp->lock, flags);
 571                         }
 572                         break;
 573                 }
 574                 for (i = 0; i < n; ++i) {
 575 #ifdef CONFIG_MAGIC_SYSRQ
 576                         /* Handle the SysRq Hack */
 577                         if (buf[i] == '\x0f') { /* ^O -- should support a sequence */
 578                                 sysrq_pressed = 1;
 579                                 continue;
 580                         } else if (sysrq_pressed) {
 581                                 handle_sysrq(buf[i], NULL, tty);
 582                                 sysrq_pressed = 0;
 583                                 continue;
 584                         }
 585 #endif /* CONFIG_MAGIC_SYSRQ */
 586                         tty_insert_flip_char(tty, buf[i], 0);
 587                 }
 588
 589                 if (tty->flip.count)
 590                         tty_schedule_flip(tty);
 591
 592                 /*
 593                  * Account for the total amount read in one loop, and if above
 594                  * 64 bytes, we do a quick schedule loop to let the tty grok the
 595                  * data and eventually throttle us.
 596                  */
 597                 read_total += n;
 598                 if (read_total >= 64) {
 599                         poll_mask |= HVC_POLL_QUICK;
 600                         break;
 601                 }
 602         }
 603  throttled:
 604         /* Wakeup write queue if necessary */
 605         if (hp->do_wakeup) {
 606                 hp->do_wakeup = 0;
 607                 tty_wakeup(tty);
 608         }
 609  bail:
 610         spin_unlock_irqrestore(&hp->lock, flags);
 611
 612         return poll_mask;
 613 }
 614
 615 #if defined(CONFIG_XMON) && defined(CONFIG_SMP)
 616 extern cpumask_t cpus_in_xmon;
 617 #else
 618 static const cpumask_t cpus_in_xmon = CPU_MASK_NONE;
 619 #endif
 620
 621 /*
 622  * This kthread is either polling or interrupt driven.  This is determined by
 623  * calling hvc_poll() who determines whether a console adapter support
 624  * interrupts.
 625  */
 626 int khvcd(void *unused)
 627 {
 628         int poll_mask;
 629         struct hvc_struct *hp;
 630
 631         __set_current_state(TASK_RUNNING);
 632         do {
 633                 poll_mask = 0;
 634                 hvc_kicked = 0;
 635                 wmb();
 636                 if (cpus_empty(cpus_in_xmon)) {
 637                         spin_lock(&hvc_structs_lock);
 638                         list_for_each_entry(hp, &hvc_structs, next) {
 639                                 /*hp = list_entry(node, struct hvc_struct, * next); */
 640                                 poll_mask |= hvc_poll(hp);
 641                         }
 642                         spin_unlock(&hvc_structs_lock);
 643                 } else
 644                         poll_mask |= HVC_POLL_READ;
 645                 if (hvc_kicked)
 646                         continue;
 647                 if (poll_mask & HVC_POLL_QUICK) {
 648                         yield();
 649                         continue;
 650                 }
 651                 set_current_state(TASK_INTERRUPTIBLE);
 652                 if (!hvc_kicked) {
 653                         if (poll_mask == 0)
 654                                 schedule();
 655                         else
 656                                 msleep_interruptible(TIMEOUT);
 657                 }
 658                 __set_current_state(TASK_RUNNING);
 659         } while (!kthread_should_stop());
 660
 661         return 0;
 662 }
 663
 664 static struct tty_operations hvc_ops = {
 665         .open = hvc_open,
 666         .close = hvc_close,
 667         .write = hvc_write,
 668         .hangup = hvc_hangup,
 669         .unthrottle = hvc_unthrottle,
 670         .write_room = hvc_write_room,
 671         .chars_in_buffer = hvc_chars_in_buffer,
 672 };
 673
 674 /* callback when the kboject ref count reaches zero. */
 675 static void destroy_hvc_struct(struct kobject *kobj)
 676 {
 677         struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj);
 678         unsigned long flags;
 679
 680         spin_lock(&hvc_structs_lock);
 681
 682         spin_lock_irqsave(&hp->lock, flags);
 683         list_del(&(hp->next));
 684         spin_unlock_irqrestore(&hp->lock, flags);
 685
 686         spin_unlock(&hvc_structs_lock);
 687
 688         kfree(hp);
 689 }
 690
 691 static struct kobj_type hvc_kobj_type = {
 692         .release = destroy_hvc_struct,
 693 };
 694
 695 static int __devinit hvc_probe(
 696                 struct vio_dev *dev,
 697                 const struct vio_device_id *id)
 698 {
 699         struct hvc_struct *hp;
 700
 701         /* probed with invalid parameters. */
 702         if (!dev || !id)
 703                 return -EPERM;
 704
 705         hp = kmalloc(sizeof(*hp), GFP_KERNEL);
 706         if (!hp)
 707                 return -ENOMEM;
 708
 709         memset(hp, 0x00, sizeof(*hp));
 710         hp->vtermno = dev->unit_address;
 711         hp->vdev = dev;
 712         hp->vdev->dev.driver_data = hp;
 713         hp->irq = dev->irq;
 714
 715         kobject_init(&hp->kobj);
 716         hp->kobj.ktype = &hvc_kobj_type;
 717
 718         spin_lock_init(&hp->lock);
 719         spin_lock(&hvc_structs_lock);
 720         hp->index = ++hvc_count;
 721         list_add_tail(&(hp->next), &hvc_structs);
 722         spin_unlock(&hvc_structs_lock);
 723
 724         return 0;
 725 }
 726
 727 static int __devexit hvc_remove(struct vio_dev *dev)
 728 {
 729         struct hvc_struct *hp = dev->dev.driver_data;
 730         unsigned long flags;
 731         struct kobject *kobjp;
 732         struct tty_struct *tty;
 733
 734         spin_lock_irqsave(&hp->lock, flags);
 735         tty = hp->tty;
 736         kobjp = &hp->kobj;
 737
 738         if (hp->index < MAX_NR_HVC_CONSOLES)
 739                 vtermnos[hp->index] = -1;
 740
 741         /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
 742
 743         spin_unlock_irqrestore(&hp->lock, flags);
 744
 745         /*
 746          * We 'put' the instance that was grabbed when the kobject instance
 747          * was intialized using kobject_init().  Let the last holder of this
 748          * kobject cause it to be removed, which will probably be the tty_hangup
 749          * below.
 750          */
 751         kobject_put(kobjp);
 752
 753         /*
 754          * This function call will auto chain call hvc_hangup.  The tty should
 755          * always be valid at this time unless a simultaneous tty close already
 756          * cleaned up the hvc_struct.
 757          */
 758         if (tty)
 759                 tty_hangup(tty);
 760         return 0;
 761 }
 762
 763 char hvc_driver_name[] = "hvc_console";
 764
 765 static struct vio_device_id hvc_driver_table[] __devinitdata= {
 766         {"serial", "hvterm1"},
 767         { NULL, }
 768 };
 769 MODULE_DEVICE_TABLE(vio, hvc_driver_table);
 770
 771 static struct vio_driver hvc_vio_driver = {
 772         .name           = hvc_driver_name,
 773         .id_table       = hvc_driver_table,
 774         .probe          = hvc_probe,
 775         .remove         = hvc_remove,
 776 };
 777
 778 /* Driver initialization.  Follow console initialization.  This is where the TTY
 779  * interfaces start to become available. */
 780 int __init hvc_init(void)
 781 {
 782         int rc;
 783
 784         /* We need more than num_vterms adapters due to hotplug additions. */
 785         hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
 786         /* hvc_driver = alloc_tty_driver(num_vterms); */
 787         if (!hvc_driver)
 788                 return -ENOMEM;
 789
 790         hvc_driver->owner = THIS_MODULE;
 791         hvc_driver->devfs_name = "hvc/";
 792         hvc_driver->driver_name = "hvc";
 793         hvc_driver->name = "hvc";
 794         hvc_driver->major = HVC_MAJOR;
 795         hvc_driver->minor_start = HVC_MINOR;
 796         hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM;
 797         hvc_driver->init_termios = tty_std_termios;
 798         hvc_driver->flags = TTY_DRIVER_REAL_RAW;
 799         tty_set_operations(hvc_driver, &hvc_ops);
 800
 801         if (tty_register_driver(hvc_driver))
 802                 panic("Couldn't register hvc console driver\n");
 803
 804         /* Always start the kthread because there can be hotplug vty adapters
 805          * added later. */
 806         hvc_task = kthread_run(khvcd, NULL, "khvcd");
 807         if (IS_ERR(hvc_task)) {
 808                 panic("Couldn't create kthread for console.\n");
 809                 put_tty_driver(hvc_driver);
 810                 return -EIO;
 811         }
 812
 813         /* Register as a vio device to receive callbacks */
 814         rc = vio_register_driver(&hvc_vio_driver);
 815
 816         return rc;
 817 }
 818 module_init(hvc_init);
 819
 820 /* This isn't particularily necessary due to this being a console driver but it
 821  * is nice to be thorough */
 822 static void __exit hvc_exit(void)
 823 {
 824         kthread_stop(hvc_task);
 825
 826         vio_unregister_driver(&hvc_vio_driver);
 827         tty_unregister_driver(hvc_driver);
 828         /* return tty_struct instances allocated in hvc_init(). */
 829         put_tty_driver(hvc_driver);
 830 }
 831 module_exit(hvc_exit);