SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 assign a tty->index value to a hvc_struct based
 106  * upon order of exposure via hvc_probe(), when we can not match it to
 107  * a console canidate registered with hvc_instantiate().
 108  */
 109 static int last_hvc = -1;
 110
 111 /*
 112  * Do not call this function with either the hvc_strucst_lock or the hvc_struct
 113  * lock held.  If successful, this function increments the kobject reference
 114  * count against the target hvc_struct so it should be released when finished.
 115  */
 116 struct hvc_struct *hvc_get_by_index(int index)
 117 {
 118         struct hvc_struct *hp;
 119         unsigned long flags;
 120
 121         spin_lock(&hvc_structs_lock);
 122
 123         list_for_each_entry(hp, &hvc_structs, next) {
 124                 spin_lock_irqsave(&hp->lock, flags);
 125                 if (hp->index == index) {
 126                         kobject_get(&hp->kobj);
 127                         spin_unlock_irqrestore(&hp->lock, flags);
 128                         spin_unlock(&hvc_structs_lock);
 129                         return hp;
 130                 }
 131                 spin_unlock_irqrestore(&hp->lock, flags);
 132         }
 133         hp = NULL;
 134
 135         spin_unlock(&hvc_structs_lock);
 136         return hp;
 137 }
 138
 139
 140 /*
 141  * Initial console vtermnos for console API usage prior to full console
 142  * initialization.  Any vty adapter outside this range will not have usable
 143  * console interfaces but can still be used as a tty device.  This has to be
 144  * static because kmalloc will not work during early console init.
 145  */
 146 static uint32_t vtermnos[MAX_NR_HVC_CONSOLES];
 147
 148 /* Used for accounting purposes */
 149 static int num_vterms = 0;
 150
 151 /*
 152  * Console APIs, NOT TTY.  These APIs are available immediately when
 153  * hvc_console_setup() finds adapters.
 154  */
 155
 156 void hvc_console_print(struct console *co, const char *b, unsigned count)
 157 {
 158         char c[16] __ALIGNED__;
 159         unsigned i = 0, n = 0;
 160         int r, donecr = 0;
 161
 162         /* Console access attempt outside of acceptable console range. */
 163         if (co->index >= MAX_NR_HVC_CONSOLES)
 164                 return;
 165
 166         /* This console adapter was removed so it is not useable. */
 167         if (vtermnos[co->index] < 0)
 168                 return;
 169
 170         while (count > 0 || i > 0) {
 171                 if (count > 0 && i < sizeof(c)) {
 172                         if (b[n] == '\n' && !donecr) {
 173                                 c[i++] = '\r';
 174                                 donecr = 1;
 175                         } else {
 176                                 c[i++] = b[n++];
 177                                 donecr = 0;
 178                                 --count;
 179                         }
 180                 } else {
 181                         r = hvc_put_chars(vtermnos[co->index], c, i);
 182                         if (r < 0) {
 183                                 /* throw away chars on error */
 184                                 i = 0;
 185                         } else if (r > 0) {
 186                                 i -= r;
 187                                 if (i > 0)
 188                                         memmove(c, c+r, i);
 189                         }
 190                 }
 191         }
 192 }
 193
 194 static struct tty_driver *hvc_console_device(struct console *c, int *index)
 195 {
 196         *index = c->index;
 197         return hvc_driver;
 198 }
 199
 200 static int __init hvc_console_setup(struct console *co, char *options)
 201 {
 202         return 0;
 203 }
 204
 205 struct console hvc_con_driver = {
 206         .name           = "hvc",
 207         .write          = hvc_console_print,
 208         .device         = hvc_console_device,
 209         .setup          = hvc_console_setup,
 210         .flags          = CON_PRINTBUFFER,
 211         .index          = -1,
 212 };
 213
 214 /* Early console initialization.  Preceeds driver initialization. */
 215 static int __init hvc_console_init(void)
 216 {
 217         int i;
 218
 219         for (i=0; i<MAX_NR_HVC_CONSOLES; i++)
 220                 vtermnos[i] = -1;
 221         num_vterms = hvc_find_vtys();
 222         register_console(&hvc_con_driver);
 223         return 0;
 224 }
 225 console_initcall(hvc_console_init);
 226
 227 /*
 228  * hvc_instantiate() is an early console discovery method which locates
 229  * consoles * prior to the vio subsystem discovering them.  Hotplugged
 230  * vty adapters do NOT get an hvc_instantiate() callback since they
 231  * appear after early console init.
 232  */
 233 int hvc_instantiate(uint32_t vtermno, int index)
 234 {
 235         if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
 236                 return -1;
 237
 238         if (vtermnos[index] != -1)
 239                 return -1;
 240
 241         vtermnos[index] = vtermno;
 242
 243         /* reserve all indices upto and including this index */
 244         if (last_hvc < index)
 245                 last_hvc = index;
 246
 247         return 0;
 248 }
 249
 250 /* Wake the sleeping khvcd */
 251 static void hvc_kick(void)
 252 {
 253         hvc_kicked = 1;
 254         wake_up_process(hvc_task);
 255 }
 256
 257 static int hvc_poll(struct hvc_struct *hp);
 258
 259 /*
 260  * NOTE: This API isn't used if the console adapter doesn't support interrupts.
 261  * In this case the console is poll driven.
 262  */
 263 static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
 264 {
 265         /* if hvc_poll request a repoll, then kick the hvcd thread */
 266         if (hvc_poll(dev_instance))
 267                 hvc_kick();
 268         return IRQ_HANDLED;
 269 }
 270
 271 static void hvc_unthrottle(struct tty_struct *tty)
 272 {
 273         hvc_kick();
 274 }
 275
 276 /*
 277  * The TTY interface won't be used until after the vio layer has exposed the vty
 278  * adapter to the kernel.
 279  */
 280 static int hvc_open(struct tty_struct *tty, struct file * filp)
 281 {
 282         struct hvc_struct *hp;
 283         unsigned long flags;
 284         int irq = NO_IRQ;
 285         int rc = 0;
 286         struct kobject *kobjp;
 287
 288         /* Auto increments kobject reference if found. */
 289         if (!(hp = hvc_get_by_index(tty->index))) {
 290                 printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n");
 291                 return -ENODEV;
 292         }
 293
 294         spin_lock_irqsave(&hp->lock, flags);
 295         /* Check and then increment for fast path open. */
 296         if (hp->count++ > 0) {
 297                 spin_unlock_irqrestore(&hp->lock, flags);
 298                 hvc_kick();
 299                 return 0;
 300         } /* else count == 0 */
 301
 302         tty->driver_data = hp;
 303         hp->tty = tty;
 304         /* Save for request_irq outside of spin_lock. */
 305         irq = hp->irq;
 306         if (irq != NO_IRQ)
 307                 hp->irq_requested = 1;
 308
 309         kobjp = &hp->kobj;
 310
 311         spin_unlock_irqrestore(&hp->lock, flags);
 312         /* check error, fallback to non-irq */
 313         if (irq != NO_IRQ)
 314                 rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp);
 315
 316         /*
 317          * If the request_irq() fails and we return an error.  The tty layer
 318          * will call hvc_close() after a failed open but we don't want to clean
 319          * up there so we'll clean up here and clear out the previously set
 320          * tty fields and return the kobject reference.
 321          */
 322         if (rc) {
 323                 spin_lock_irqsave(&hp->lock, flags);
 324                 hp->tty = NULL;
 325                 hp->irq_requested = 0;
 326                 spin_unlock_irqrestore(&hp->lock, flags);
 327                 tty->driver_data = NULL;
 328                 kobject_put(kobjp);
 329                 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
 330         }
 331         /* Force wakeup of the polling thread */
 332         hvc_kick();
 333
 334         return rc;
 335 }
 336
 337 static void hvc_close(struct tty_struct *tty, struct file * filp)
 338 {
 339         struct hvc_struct *hp;
 340         struct kobject *kobjp;
 341         int irq = NO_IRQ;
 342         unsigned long flags;
 343
 344         if (tty_hung_up_p(filp))
 345                 return;
 346
 347         /*
 348          * No driver_data means that this close was issued after a failed
 349          * hvc_open by the tty layer's release_dev() function and we can just
 350          * exit cleanly because the kobject reference wasn't made.
 351          */
 352         if (!tty->driver_data)
 353                 return;
 354
 355         hp = tty->driver_data;
 356         spin_lock_irqsave(&hp->lock, flags);
 357
 358         kobjp = &hp->kobj;
 359         if (--hp->count == 0) {
 360                 if (hp->irq_requested)
 361                         irq = hp->irq;
 362                 hp->irq_requested = 0;
 363
 364                 /* We are done with the tty pointer now. */
 365                 hp->tty = NULL;
 366                 spin_unlock_irqrestore(&hp->lock, flags);
 367
 368                 /*
 369                  * Chain calls chars_in_buffer() and returns immediately if
 370                  * there is no buffered data otherwise sleeps on a wait queue
 371                  * waking periodically to check chars_in_buffer().
 372                  */
 373                 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
 374
 375                 if (irq != NO_IRQ)
 376                         free_irq(irq, hp);
 377
 378         } else {
 379                 if (hp->count < 0)
 380                         printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
 381                                 hp->vtermno, hp->count);
 382                 spin_unlock_irqrestore(&hp->lock, flags);
 383         }
 384
 385         kobject_put(kobjp);
 386 }
 387
 388 static void hvc_hangup(struct tty_struct *tty)
 389 {
 390         struct hvc_struct *hp = tty->driver_data;
 391         unsigned long flags;
 392         int irq = NO_IRQ;
 393         int temp_open_count;
 394         struct kobject *kobjp;
 395
 396         if (!hp)
 397                 return;
 398
 399         spin_lock_irqsave(&hp->lock, flags);
 400
 401         /*
 402          * The N_TTY line discipline has problems such that in a close vs
 403          * open->hangup case this can be called after the final close so prevent
 404          * that from happening for now.
 405          */
 406         if (hp->count <= 0) {
 407                 spin_unlock_irqrestore(&hp->lock, flags);
 408                 return;
 409         }
 410
 411         kobjp = &hp->kobj;
 412         temp_open_count = hp->count;
 413         hp->count = 0;
 414         hp->n_outbuf = 0;
 415         hp->tty = NULL;
 416         if (hp->irq_requested)
 417                 /* Saved for use outside of spin_lock. */
 418                 irq = hp->irq;
 419         hp->irq_requested = 0;
 420         spin_unlock_irqrestore(&hp->lock, flags);
 421         if (irq != NO_IRQ)
 422                 free_irq(irq, hp);
 423         while(temp_open_count) {
 424                 --temp_open_count;
 425                 kobject_put(kobjp);
 426         }
 427 }
 428
 429 /*
 430  * Push buffered characters whether they were just recently buffered or waiting
 431  * on a blocked hypervisor.  Call this function with hp->lock held.
 432  */
 433 static void hvc_push(struct hvc_struct *hp)
 434 {
 435         int n;
 436
 437         n = hvc_put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
 438         if (n <= 0) {
 439                 if (n == 0)
 440                         return;
 441                 /* throw away output on error; this happens when
 442                    there is no session connected to the vterm. */
 443                 hp->n_outbuf = 0;
 444         } else
 445                 hp->n_outbuf -= n;
 446         if (hp->n_outbuf > 0)
 447                 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
 448         else
 449                 hp->do_wakeup = 1;
 450 }
 451
 452 static inline int __hvc_write_kernel(struct hvc_struct *hp,
 453                                    const unsigned char *buf, int count)
 454 {
 455         unsigned long flags;
 456         int rsize, written = 0;
 457
 458         spin_lock_irqsave(&hp->lock, flags);
 459
 460         /* Push pending writes */
 461         if (hp->n_outbuf > 0)
 462                 hvc_push(hp);
 463
 464         while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) {
 465                 if (rsize > count)
 466                         rsize = count;
 467                 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
 468                 count -= rsize;
 469                 buf += rsize;
 470                 hp->n_outbuf += rsize;
 471                 written += rsize;
 472                 hvc_push(hp);
 473         }
 474         spin_unlock_irqrestore(&hp->lock, flags);
 475
 476         return written;
 477 }
 478 static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
 479 {
 480         struct hvc_struct *hp = tty->driver_data;
 481         int written;
 482
 483         /* This write was probably executed during a tty close. */
 484         if (!hp)
 485                 return -EPIPE;
 486
 487         if (hp->count <= 0)
 488                 return -EIO;
 489
 490         written = __hvc_write_kernel(hp, buf, count);
 491
 492         /*
 493          * Racy, but harmless, kick thread if there is still pending data.
 494          * There really is nothing wrong with kicking the thread, even if there
 495          * is no buffered data.
 496          */
 497         if (hp->n_outbuf)
 498                 hvc_kick();
 499
 500         return written;
 501 }
 502
 503 /*
 504  * This is actually a contract between the driver and the tty layer outlining
 505  * how much write room the driver can guarentee will be sent OR BUFFERED.  This
 506  * driver MUST honor the return value.
 507  */
 508 static int hvc_write_room(struct tty_struct *tty)
 509 {
 510         struct hvc_struct *hp = tty->driver_data;
 511
 512         if (!hp)
 513                 return -1;
 514
 515         return N_OUTBUF - hp->n_outbuf;
 516 }
 517
 518 static int hvc_chars_in_buffer(struct tty_struct *tty)
 519 {
 520         struct hvc_struct *hp = tty->driver_data;
 521
 522         if (!hp)
 523                 return -1;
 524         return hp->n_outbuf;
 525 }
 526
 527 #define HVC_POLL_READ   0x00000001
 528 #define HVC_POLL_WRITE  0x00000002
 529 #define HVC_POLL_QUICK  0x00000004
 530
 531 static int hvc_poll(struct hvc_struct *hp)
 532 {
 533         struct tty_struct *tty;
 534         int i, n, poll_mask = 0;
 535         char buf[N_INBUF] __ALIGNED__;
 536         unsigned long flags;
 537         int read_total = 0;
 538
 539         spin_lock_irqsave(&hp->lock, flags);
 540
 541         /* Push pending writes */
 542         if (hp->n_outbuf > 0)
 543                 hvc_push(hp);
 544         /* Reschedule us if still some write pending */
 545         if (hp->n_outbuf > 0)
 546                 poll_mask |= HVC_POLL_WRITE;
 547
 548         /* No tty attached, just skip */
 549         tty = hp->tty;
 550         if (tty == NULL)
 551                 goto bail;
 552
 553         /* Now check if we can get data (are we throttled ?) */
 554         if (test_bit(TTY_THROTTLED, &tty->flags))
 555                 goto throttled;
 556
 557         /* If we aren't interrupt driven and aren't throttled, we always
 558          * request a reschedule
 559          */
 560         if (hp->irq == NO_IRQ)
 561                 poll_mask |= HVC_POLL_READ;
 562
 563         /* Read data if any */
 564         for (;;) {
 565                 int count = N_INBUF;
 566                 if (count > (TTY_FLIPBUF_SIZE - tty->flip.count))
 567                         count = TTY_FLIPBUF_SIZE - tty->flip.count;
 568
 569                 /* If flip is full, just reschedule a later read */
 570                 if (count == 0) {
 571                         poll_mask |= HVC_POLL_READ;
 572                         break;
 573                 }
 574
 575                 n = hvc_get_chars(hp->vtermno, buf, count);
 576                 if (n <= 0) {
 577                         /* Hangup the tty when disconnected from host */
 578                         if (n == -EPIPE) {
 579                                 spin_unlock_irqrestore(&hp->lock, flags);
 580                                 tty_hangup(tty);
 581                                 spin_lock_irqsave(&hp->lock, flags);
 582                         }
 583                         break;
 584                 }
 585                 for (i = 0; i < n; ++i) {
 586 #ifdef CONFIG_MAGIC_SYSRQ
 587                         if (hp->index == hvc_con_driver.index) {
 588                                 /* Handle the SysRq Hack */
 589                                 /* XXX should support a sequence */
 590                                 if (buf[i] == '\x0f') { /* ^O */
 591                                         sysrq_pressed = 1;
 592                                         continue;
 593                                 } else if (sysrq_pressed) {
 594                                         handle_sysrq(buf[i], NULL, tty);
 595                                         sysrq_pressed = 0;
 596                                         continue;
 597                                 }
 598                         }
 599 #endif /* CONFIG_MAGIC_SYSRQ */
 600                         tty_insert_flip_char(tty, buf[i], 0);
 601                 }
 602
 603                 if (tty->flip.count)
 604                         tty_schedule_flip(tty);
 605
 606                 /*
 607                  * Account for the total amount read in one loop, and if above
 608                  * 64 bytes, we do a quick schedule loop to let the tty grok
 609                  * the data and eventually throttle us.
 610                  */
 611                 read_total += n;
 612                 if (read_total >= 64) {
 613                         poll_mask |= HVC_POLL_QUICK;
 614                         break;
 615                 }
 616         }
 617  throttled:
 618         /* Wakeup write queue if necessary */
 619         if (hp->do_wakeup) {
 620                 hp->do_wakeup = 0;
 621                 tty_wakeup(tty);
 622         }
 623  bail:
 624         spin_unlock_irqrestore(&hp->lock, flags);
 625
 626         return poll_mask;
 627 }
 628
 629 #if defined(CONFIG_XMON) && defined(CONFIG_SMP)
 630 extern cpumask_t cpus_in_xmon;
 631 #else
 632 static const cpumask_t cpus_in_xmon = CPU_MASK_NONE;
 633 #endif
 634
 635 /*
 636  * This kthread is either polling or interrupt driven.  This is determined by
 637  * calling hvc_poll() who determines whether a console adapter support
 638  * interrupts.
 639  */
 640 int khvcd(void *unused)
 641 {
 642         int poll_mask;
 643         struct hvc_struct *hp;
 644
 645         __set_current_state(TASK_RUNNING);
 646         do {
 647                 poll_mask = 0;
 648                 hvc_kicked = 0;
 649                 wmb();
 650                 if (cpus_empty(cpus_in_xmon)) {
 651                         spin_lock(&hvc_structs_lock);
 652                         list_for_each_entry(hp, &hvc_structs, next) {
 653                                 /*hp = list_entry(node, struct hvc_struct, * next); */
 654                                 poll_mask |= hvc_poll(hp);
 655                         }
 656                         spin_unlock(&hvc_structs_lock);
 657                 } else
 658                         poll_mask |= HVC_POLL_READ;
 659                 if (hvc_kicked)
 660                         continue;
 661                 if (poll_mask & HVC_POLL_QUICK) {
 662                         yield();
 663                         continue;
 664                 }
 665                 set_current_state(TASK_INTERRUPTIBLE);
 666                 if (!hvc_kicked) {
 667                         if (poll_mask == 0)
 668                                 schedule();
 669                         else
 670                                 msleep_interruptible(TIMEOUT);
 671                 }
 672                 __set_current_state(TASK_RUNNING);
 673         } while (!kthread_should_stop());
 674
 675         return 0;
 676 }
 677
 678 static struct tty_operations hvc_ops = {
 679         .open = hvc_open,
 680         .close = hvc_close,
 681         .write = hvc_write,
 682         .hangup = hvc_hangup,
 683         .unthrottle = hvc_unthrottle,
 684         .write_room = hvc_write_room,
 685         .chars_in_buffer = hvc_chars_in_buffer,
 686 };
 687
 688 /* callback when the kboject ref count reaches zero. */
 689 static void destroy_hvc_struct(struct kobject *kobj)
 690 {
 691         struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj);
 692         unsigned long flags;
 693
 694         spin_lock(&hvc_structs_lock);
 695
 696         spin_lock_irqsave(&hp->lock, flags);
 697         list_del(&(hp->next));
 698         spin_unlock_irqrestore(&hp->lock, flags);
 699
 700         spin_unlock(&hvc_structs_lock);
 701
 702         kfree(hp);
 703 }
 704
 705 static struct kobj_type hvc_kobj_type = {
 706         .release = destroy_hvc_struct,
 707 };
 708
 709 static int __devinit hvc_probe(
 710                 struct vio_dev *dev,
 711                 const struct vio_device_id *id)
 712 {
 713         struct hvc_struct *hp;
 714         int i;
 715
 716         /* probed with invalid parameters. */
 717         if (!dev || !id)
 718                 return -EPERM;
 719
 720         hp = kmalloc(sizeof(*hp), GFP_KERNEL);
 721         if (!hp)
 722                 return -ENOMEM;
 723
 724         memset(hp, 0x00, sizeof(*hp));
 725         hp->vtermno = dev->unit_address;
 726         hp->vdev = dev;
 727         hp->vdev->dev.driver_data = hp;
 728         hp->irq = dev->irq;
 729
 730         kobject_init(&hp->kobj);
 731         hp->kobj.ktype = &hvc_kobj_type;
 732
 733         spin_lock_init(&hp->lock);
 734         spin_lock(&hvc_structs_lock);
 735
 736         /*
 737          * find index to use:
 738          * see if this vterm id matches one registered for console.
 739          */
 740         for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
 741                 if (vtermnos[i] == hp->vtermno)
 742                         break;
 743
 744         /* no matching slot, just use a counter */
 745         if (i >= MAX_NR_HVC_CONSOLES)
 746                 i = ++last_hvc;
 747
 748         hp->index = i;
 749
 750         list_add_tail(&(hp->next), &hvc_structs);
 751         spin_unlock(&hvc_structs_lock);
 752
 753         return 0;
 754 }
 755
 756 static int __devexit hvc_remove(struct vio_dev *dev)
 757 {
 758         struct hvc_struct *hp = dev->dev.driver_data;
 759         unsigned long flags;
 760         struct kobject *kobjp;
 761         struct tty_struct *tty;
 762
 763         spin_lock_irqsave(&hp->lock, flags);
 764         tty = hp->tty;
 765         kobjp = &hp->kobj;
 766
 767         if (hp->index < MAX_NR_HVC_CONSOLES)
 768                 vtermnos[hp->index] = -1;
 769
 770         /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
 771
 772         spin_unlock_irqrestore(&hp->lock, flags);
 773
 774         /*
 775          * We 'put' the instance that was grabbed when the kobject instance
 776          * was intialized using kobject_init().  Let the last holder of this
 777          * kobject cause it to be removed, which will probably be the tty_hangup
 778          * below.
 779          */
 780         kobject_put(kobjp);
 781
 782         /*
 783          * This function call will auto chain call hvc_hangup.  The tty should
 784          * always be valid at this time unless a simultaneous tty close already
 785          * cleaned up the hvc_struct.
 786          */
 787         if (tty)
 788                 tty_hangup(tty);
 789         return 0;
 790 }
 791
 792 char hvc_driver_name[] = "hvc_console";
 793
 794 static struct vio_device_id hvc_driver_table[] __devinitdata= {
 795         {"serial", "hvterm1"},
 796         { NULL, }
 797 };
 798 MODULE_DEVICE_TABLE(vio, hvc_driver_table);
 799
 800 static struct vio_driver hvc_vio_driver = {
 801         .name           = hvc_driver_name,
 802         .id_table       = hvc_driver_table,
 803         .probe          = hvc_probe,
 804         .remove         = hvc_remove,
 805 };
 806
 807 /* Driver initialization.  Follow console initialization.  This is where the TTY
 808  * interfaces start to become available. */
 809 int __init hvc_init(void)
 810 {
 811         int rc;
 812
 813         /* We need more than num_vterms adapters due to hotplug additions. */
 814         hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
 815         /* hvc_driver = alloc_tty_driver(num_vterms); */
 816         if (!hvc_driver)
 817                 return -ENOMEM;
 818
 819         hvc_driver->owner = THIS_MODULE;
 820         hvc_driver->devfs_name = "hvc/";
 821         hvc_driver->driver_name = "hvc";
 822         hvc_driver->name = "hvc";
 823         hvc_driver->major = HVC_MAJOR;
 824         hvc_driver->minor_start = HVC_MINOR;
 825         hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM;
 826         hvc_driver->init_termios = tty_std_termios;
 827         hvc_driver->flags = TTY_DRIVER_REAL_RAW;
 828         tty_set_operations(hvc_driver, &hvc_ops);
 829
 830         if (tty_register_driver(hvc_driver))
 831                 panic("Couldn't register hvc console driver\n");
 832
 833         /* Always start the kthread because there can be hotplug vty adapters
 834          * added later. */
 835         hvc_task = kthread_run(khvcd, NULL, "khvcd");
 836         if (IS_ERR(hvc_task)) {
 837                 panic("Couldn't create kthread for console.\n");
 838                 put_tty_driver(hvc_driver);
 839                 return -EIO;
 840         }
 841
 842         /* Register as a vio device to receive callbacks */
 843         rc = vio_register_driver(&hvc_vio_driver);
 844
 845         return rc;
 846 }
 847 module_init(hvc_init);
 848
 849 /* This isn't particularily necessary due to this being a console driver but it
 850  * is nice to be thorough */
 851 static void __exit hvc_exit(void)
 852 {
 853         kthread_stop(hvc_task);
 854
 855         vio_unregister_driver(&hvc_vio_driver);
 856         tty_unregister_driver(hvc_driver);
 857         /* return tty_struct instances allocated in hvc_init(). */
 858         put_tty_driver(hvc_driver);
 859 }
 860 module_exit(hvc_exit);