drivers/tty/vcc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* vcc.c: sun4v virtual channel concentrator
   3  *
   4  * Copyright (C) 2017 Oracle. All rights reserved.
   5  */
   6
   7 #include <linux/delay.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/sysfs.h>
  12 #include <linux/tty.h>
  13 #include <linux/tty_flip.h>
  14 #include <asm/vio.h>
  15 #include <asm/ldc.h>
  16
  17 #define DRV_MODULE_NAME         "vcc"
  18 #define DRV_MODULE_VERSION      "1.1"
  19 #define DRV_MODULE_RELDATE      "July 1, 2017"
  20
  21 static char version[] =
  22         DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")";
  23
  24 MODULE_DESCRIPTION("Sun LDOM virtual console concentrator driver");
  25 MODULE_LICENSE("GPL");
  26 MODULE_VERSION(DRV_MODULE_VERSION);
  27
  28 struct vcc_port {
  29         struct vio_driver_state vio;
  30
  31         spinlock_t lock;
  32         char *domain;
  33         struct tty_struct *tty; /* only populated while dev is open */
  34         unsigned long index;    /* index into the vcc_table */
  35
  36         u64 refcnt;
  37         bool excl_locked;
  38
  39         bool removed;
  40
  41         /* This buffer is required to support the tty write_room interface
  42          * and guarantee that any characters that the driver accepts will
  43          * be eventually sent, either immediately or later.
  44          */
  45         int chars_in_buffer;
  46         struct vio_vcc buffer;
  47
  48         struct timer_list rx_timer;
  49         struct timer_list tx_timer;
  50 };
  51
  52 /* Microseconds that thread will delay waiting for a vcc port ref */
  53 #define VCC_REF_DELAY           100
  54
  55 #define VCC_MAX_PORTS           1024
  56 #define VCC_MINOR_START         0       /* must be zero */
  57 #define VCC_BUFF_LEN            VIO_VCC_MTU_SIZE
  58
  59 #define VCC_CTL_BREAK           -1
  60 #define VCC_CTL_HUP             -2
  61
  62 static const char vcc_driver_name[] = "vcc";
  63 static const char vcc_device_node[] = "vcc";
  64 static struct tty_driver *vcc_tty_driver;
  65
  66 static struct vcc_port *vcc_table[VCC_MAX_PORTS];
  67 static DEFINE_SPINLOCK(vcc_table_lock);
  68
  69 int vcc_dbg;
  70 int vcc_dbg_ldc;
  71 int vcc_dbg_vio;
  72
  73 module_param(vcc_dbg, uint, 0664);
  74 module_param(vcc_dbg_ldc, uint, 0664);
  75 module_param(vcc_dbg_vio, uint, 0664);
  76
  77 #define VCC_DBG_DRV     0x1
  78 #define VCC_DBG_LDC     0x2
  79 #define VCC_DBG_PKT     0x4
  80
  81 #define vccdbg(f, a...)                                         \
  82         do {                                                    \
  83                 if (vcc_dbg & VCC_DBG_DRV)                      \
  84                         pr_info(f, ## a);                       \
  85         } while (0)                                             \
  86
  87 #define vccdbgl(l)                                              \
  88         do {                                                    \
  89                 if (vcc_dbg & VCC_DBG_LDC)                      \
  90                         ldc_print(l);                           \
  91         } while (0)                                             \
  92
  93 #define vccdbgp(pkt)                                            \
  94         do {                                                    \
  95                 if (vcc_dbg & VCC_DBG_PKT) {                    \
  96                         int i;                                  \
  97                         for (i = 0; i < pkt.tag.stype; i++)     \
  98                                 pr_info("[%c]", pkt.data[i]);   \
  99                 }                                               \
 100         } while (0)                                             \
 101
 102 /* Note: Be careful when adding flags to this line discipline.  Don't
 103  * add anything that will cause echoing or we'll go into recursive
 104  * loop echoing chars back and forth with the console drivers.
 105  */
 106 static const struct ktermios vcc_tty_termios = {
 107         .c_iflag = IGNBRK | IGNPAR,
 108         .c_oflag = OPOST,
 109         .c_cflag = B38400 | CS8 | CREAD | HUPCL,
 110         .c_cc = INIT_C_CC,
 111         .c_ispeed = 38400,
 112         .c_ospeed = 38400
 113 };
 114
 115 /**
 116  * vcc_table_add() - Add VCC port to the VCC table
 117  * @port: pointer to the VCC port
 118  *
 119  * Return: index of the port in the VCC table on success,
 120  *         -1 on failure
 121  */
 122 static int vcc_table_add(struct vcc_port *port)
 123 {
 124         unsigned long flags;
 125         int i;
 126
 127         spin_lock_irqsave(&vcc_table_lock, flags);
 128         for (i = VCC_MINOR_START; i < VCC_MAX_PORTS; i++) {
 129                 if (!vcc_table[i]) {
 130                         vcc_table[i] = port;
 131                         break;
 132                 }
 133         }
 134         spin_unlock_irqrestore(&vcc_table_lock, flags);
 135
 136         if (i < VCC_MAX_PORTS)
 137                 return i;
 138         else
 139                 return -1;
 140 }
 141
 142 /**
 143  * vcc_table_remove() - Removes a VCC port from the VCC table
 144  * @index: Index into the VCC table
 145  */
 146 static void vcc_table_remove(unsigned long index)
 147 {
 148         unsigned long flags;
 149
 150         if (WARN_ON(index >= VCC_MAX_PORTS))
 151                 return;
 152
 153         spin_lock_irqsave(&vcc_table_lock, flags);
 154         vcc_table[index] = NULL;
 155         spin_unlock_irqrestore(&vcc_table_lock, flags);
 156 }
 157
 158 /**
 159  * vcc_get() - Gets a reference to VCC port
 160  * @index: Index into the VCC table
 161  * @excl: Indicates if an exclusive access is requested
 162  *
 163  * Return: reference to the VCC port, if found
 164  *         NULL, if port not found
 165  */
 166 static struct vcc_port *vcc_get(unsigned long index, bool excl)
 167 {
 168         struct vcc_port *port;
 169         unsigned long flags;
 170
 171 try_again:
 172         spin_lock_irqsave(&vcc_table_lock, flags);
 173
 174         port = vcc_table[index];
 175         if (!port) {
 176                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 177                 return NULL;
 178         }
 179
 180         if (!excl) {
 181                 if (port->excl_locked) {
 182                         spin_unlock_irqrestore(&vcc_table_lock, flags);
 183                         udelay(VCC_REF_DELAY);
 184                         goto try_again;
 185                 }
 186                 port->refcnt++;
 187                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 188                 return port;
 189         }
 190
 191         if (port->refcnt) {
 192                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 193                 /* Threads wanting exclusive access will wait half the time,
 194                  * probably giving them higher priority in the case of
 195                  * multiple waiters.
 196                  */
 197                 udelay(VCC_REF_DELAY/2);
 198                 goto try_again;
 199         }
 200
 201         port->refcnt++;
 202         port->excl_locked = true;
 203         spin_unlock_irqrestore(&vcc_table_lock, flags);
 204
 205         return port;
 206 }
 207
 208 /**
 209  * vcc_put() - Returns a reference to VCC port
 210  * @port: pointer to VCC port
 211  * @excl: Indicates if the returned reference is an exclusive reference
 212  *
 213  * Note: It's the caller's responsibility to ensure the correct value
 214  *       for the excl flag
 215  */
 216 static void vcc_put(struct vcc_port *port, bool excl)
 217 {
 218         unsigned long flags;
 219
 220         if (!port)
 221                 return;
 222
 223         spin_lock_irqsave(&vcc_table_lock, flags);
 224
 225         /* check if caller attempted to put with the wrong flags */
 226         if (WARN_ON((excl && !port->excl_locked) ||
 227                     (!excl && port->excl_locked)))
 228                 goto done;
 229
 230         port->refcnt--;
 231
 232         if (excl)
 233                 port->excl_locked = false;
 234
 235 done:
 236         spin_unlock_irqrestore(&vcc_table_lock, flags);
 237 }
 238
 239 /**
 240  * vcc_get_ne() - Get a non-exclusive reference to VCC port
 241  * @index: Index into the VCC table
 242  *
 243  * Gets a non-exclusive reference to VCC port, if it's not removed
 244  *
 245  * Return: pointer to the VCC port, if found
 246  *         NULL, if port not found
 247  */
 248 static struct vcc_port *vcc_get_ne(unsigned long index)
 249 {
 250         struct vcc_port *port;
 251
 252         port = vcc_get(index, false);
 253
 254         if (port && port->removed) {
 255                 vcc_put(port, false);
 256                 return NULL;
 257         }
 258
 259         return port;
 260 }
 261
 262 static void vcc_kick_rx(struct vcc_port *port)
 263 {
 264         struct vio_driver_state *vio = &port->vio;
 265
 266         assert_spin_locked(&port->lock);
 267
 268         if (!timer_pending(&port->rx_timer) && !port->removed) {
 269                 disable_irq_nosync(vio->vdev->rx_irq);
 270                 port->rx_timer.expires = (jiffies + 1);
 271                 add_timer(&port->rx_timer);
 272         }
 273 }
 274
 275 static void vcc_kick_tx(struct vcc_port *port)
 276 {
 277         assert_spin_locked(&port->lock);
 278
 279         if (!timer_pending(&port->tx_timer) && !port->removed) {
 280                 port->tx_timer.expires = (jiffies + 1);
 281                 add_timer(&port->tx_timer);
 282         }
 283 }
 284
 285 static int vcc_rx_check(struct tty_struct *tty, int size)
 286 {
 287         if (WARN_ON(!tty || !tty->port))
 288                 return 1;
 289
 290         /* tty_buffer_request_room won't sleep because it uses
 291          * GFP_ATOMIC flag to allocate buffer
 292          */
 293         if (test_bit(TTY_THROTTLED, &tty->flags) ||
 294             (tty_buffer_request_room(tty->port, VCC_BUFF_LEN) < VCC_BUFF_LEN))
 295                 return 0;
 296
 297         return 1;
 298 }
 299
 300 static int vcc_rx(struct tty_struct *tty, char *buf, int size)
 301 {
 302         int len = 0;
 303
 304         if (WARN_ON(!tty || !tty->port))
 305                 return len;
 306
 307         len = tty_insert_flip_string(tty->port, buf, size);
 308         if (len)
 309                 tty_flip_buffer_push(tty->port);
 310
 311         return len;
 312 }
 313
 314 static int vcc_ldc_read(struct vcc_port *port)
 315 {
 316         struct vio_driver_state *vio = &port->vio;
 317         struct tty_struct *tty;
 318         struct vio_vcc pkt;
 319         int rv = 0;
 320
 321         tty = port->tty;
 322         if (!tty) {
 323                 rv = ldc_rx_reset(vio->lp);
 324                 vccdbg("VCC: reset rx q: rv=%d\n", rv);
 325                 goto done;
 326         }
 327
 328         /* Read as long as LDC has incoming data. */
 329         while (1) {
 330                 if (!vcc_rx_check(tty, VIO_VCC_MTU_SIZE)) {
 331                         vcc_kick_rx(port);
 332                         break;
 333                 }
 334
 335                 vccdbgl(vio->lp);
 336
 337                 rv = ldc_read(vio->lp, &pkt, sizeof(pkt));
 338                 if (rv <= 0)
 339                         break;
 340
 341                 vccdbg("VCC: ldc_read()=%d\n", rv);
 342                 vccdbg("TAG [%02x:%02x:%04x:%08x]\n",
 343                        pkt.tag.type, pkt.tag.stype,
 344                        pkt.tag.stype_env, pkt.tag.sid);
 345
 346                 if (pkt.tag.type == VIO_TYPE_DATA) {
 347                         vccdbgp(pkt);
 348                         /* vcc_rx_check ensures memory availability */
 349                         vcc_rx(tty, pkt.data, pkt.tag.stype);
 350                 } else {
 351                         pr_err("VCC: unknown msg [%02x:%02x:%04x:%08x]\n",
 352                                pkt.tag.type, pkt.tag.stype,
 353                                pkt.tag.stype_env, pkt.tag.sid);
 354                         rv = -ECONNRESET;
 355                         break;
 356                 }
 357
 358                 WARN_ON(rv != LDC_PACKET_SIZE);
 359         }
 360
 361 done:
 362         return rv;
 363 }
 364
 365 static void vcc_rx_timer(struct timer_list *t)
 366 {
 367         struct vcc_port *port = from_timer(port, t, rx_timer);
 368         struct vio_driver_state *vio;
 369         unsigned long flags;
 370         int rv;
 371
 372         spin_lock_irqsave(&port->lock, flags);
 373         port->rx_timer.expires = 0;
 374
 375         vio = &port->vio;
 376
 377         enable_irq(vio->vdev->rx_irq);
 378
 379         if (!port->tty || port->removed)
 380                 goto done;
 381
 382         rv = vcc_ldc_read(port);
 383         if (rv == -ECONNRESET)
 384                 vio_conn_reset(vio);
 385
 386 done:
 387         spin_unlock_irqrestore(&port->lock, flags);
 388         vcc_put(port, false);
 389 }
 390
 391 static void vcc_tx_timer(struct timer_list *t)
 392 {
 393         struct vcc_port *port = from_timer(port, t, tx_timer);
 394         struct vio_vcc *pkt;
 395         unsigned long flags;
 396         int tosend = 0;
 397         int rv;
 398
 399         spin_lock_irqsave(&port->lock, flags);
 400         port->tx_timer.expires = 0;
 401
 402         if (!port->tty || port->removed)
 403                 goto done;
 404
 405         tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
 406         if (!tosend)
 407                 goto done;
 408
 409         pkt = &port->buffer;
 410         pkt->tag.type = VIO_TYPE_DATA;
 411         pkt->tag.stype = tosend;
 412         vccdbgl(port->vio.lp);
 413
 414         rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 415         WARN_ON(!rv);
 416
 417         if (rv < 0) {
 418                 vccdbg("VCC: ldc_write()=%d\n", rv);
 419                 vcc_kick_tx(port);
 420         } else {
 421                 struct tty_struct *tty = port->tty;
 422
 423                 port->chars_in_buffer = 0;
 424                 if (tty)
 425                         tty_wakeup(tty);
 426         }
 427
 428 done:
 429         spin_unlock_irqrestore(&port->lock, flags);
 430         vcc_put(port, false);
 431 }
 432
 433 /**
 434  * vcc_event() - LDC event processing engine
 435  * @arg: VCC private data
 436  * @event: LDC event
 437  *
 438  * Handles LDC events for VCC
 439  */
 440 static void vcc_event(void *arg, int event)
 441 {
 442         struct vio_driver_state *vio;
 443         struct vcc_port *port;
 444         unsigned long flags;
 445         int rv;
 446
 447         port = arg;
 448         vio = &port->vio;
 449
 450         spin_lock_irqsave(&port->lock, flags);
 451
 452         switch (event) {
 453         case LDC_EVENT_RESET:
 454         case LDC_EVENT_UP:
 455                 vio_link_state_change(vio, event);
 456                 break;
 457
 458         case LDC_EVENT_DATA_READY:
 459                 rv = vcc_ldc_read(port);
 460                 if (rv == -ECONNRESET)
 461                         vio_conn_reset(vio);
 462                 break;
 463
 464         default:
 465                 pr_err("VCC: unexpected LDC event(%d)\n", event);
 466         }
 467
 468         spin_unlock_irqrestore(&port->lock, flags);
 469 }
 470
 471 static struct ldc_channel_config vcc_ldc_cfg = {
 472         .event          = vcc_event,
 473         .mtu            = VIO_VCC_MTU_SIZE,
 474         .mode           = LDC_MODE_RAW,
 475         .debug          = 0,
 476 };
 477
 478 /* Ordered from largest major to lowest */
 479 static struct vio_version vcc_versions[] = {
 480         { .major = 1, .minor = 0 },
 481 };
 482
 483 static struct tty_port_operations vcc_port_ops = { 0 };
 484
 485 static ssize_t vcc_sysfs_domain_show(struct device *dev,
 486                                      struct device_attribute *attr,
 487                                      char *buf)
 488 {
 489         struct vcc_port *port;
 490         int rv;
 491
 492         port = dev_get_drvdata(dev);
 493         if (!port)
 494                 return -ENODEV;
 495
 496         rv = scnprintf(buf, PAGE_SIZE, "%s\n", port->domain);
 497
 498         return rv;
 499 }
 500
 501 static int vcc_send_ctl(struct vcc_port *port, int ctl)
 502 {
 503         struct vio_vcc pkt;
 504         int rv;
 505
 506         pkt.tag.type = VIO_TYPE_CTRL;
 507         pkt.tag.sid = ctl;
 508         pkt.tag.stype = 0;
 509
 510         rv = ldc_write(port->vio.lp, &pkt, sizeof(pkt.tag));
 511         WARN_ON(!rv);
 512         vccdbg("VCC: ldc_write(%ld)=%d\n", sizeof(pkt.tag), rv);
 513
 514         return rv;
 515 }
 516
 517 static ssize_t vcc_sysfs_break_store(struct device *dev,
 518                                      struct device_attribute *attr,
 519                                      const char *buf, size_t count)
 520 {
 521         struct vcc_port *port;
 522         unsigned long flags;
 523         int rv = count;
 524         int brk;
 525
 526         port = dev_get_drvdata(dev);
 527         if (!port)
 528                 return -ENODEV;
 529
 530         spin_lock_irqsave(&port->lock, flags);
 531
 532         if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
 533                 rv = -EINVAL;
 534         else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 535                 vcc_kick_tx(port);
 536
 537         spin_unlock_irqrestore(&port->lock, flags);
 538
 539         return rv;
 540 }
 541
 542 static DEVICE_ATTR(domain, 0400, vcc_sysfs_domain_show, NULL);
 543 static DEVICE_ATTR(break, 0200, NULL, vcc_sysfs_break_store);
 544
 545 static struct attribute *vcc_sysfs_entries[] = {
 546         &dev_attr_domain.attr,
 547         &dev_attr_break.attr,
 548         NULL
 549 };
 550
 551 static struct attribute_group vcc_attribute_group = {
 552         .name = NULL,
 553         .attrs = vcc_sysfs_entries,
 554 };
 555
 556 /**
 557  * vcc_probe() - Initialize VCC port
 558  * @vdev: Pointer to VIO device of the new VCC port
 559  * @id: VIO device ID
 560  *
 561  * Initializes a VCC port to receive serial console data from
 562  * the guest domain. Sets up a TTY end point on the control
 563  * domain. Sets up VIO/LDC link between the guest & control
 564  * domain endpoints.
 565  *
 566  * Return: status of the probe
 567  */
 568 static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 569 {
 570         struct mdesc_handle *hp;
 571         struct vcc_port *port;
 572         struct device *dev;
 573         const char *domain;
 574         char *name;
 575         u64 node;
 576         int rv;
 577
 578         vccdbg("VCC: name=%s\n", dev_name(&vdev->dev));
 579
 580         if (!vcc_tty_driver) {
 581                 pr_err("VCC: TTY driver not registered\n");
 582                 return -ENODEV;
 583         }
 584
 585         port = kzalloc(sizeof(struct vcc_port), GFP_KERNEL);
 586         if (!port)
 587                 return -ENOMEM;
 588
 589         name = kstrdup(dev_name(&vdev->dev), GFP_KERNEL);
 590
 591         rv = vio_driver_init(&port->vio, vdev, VDEV_CONSOLE_CON, vcc_versions,
 592                              ARRAY_SIZE(vcc_versions), NULL, name);
 593         if (rv)
 594                 goto free_port;
 595
 596         port->vio.debug = vcc_dbg_vio;
 597         vcc_ldc_cfg.debug = vcc_dbg_ldc;
 598
 599         rv = vio_ldc_alloc(&port->vio, &vcc_ldc_cfg, port);
 600         if (rv)
 601                 goto free_port;
 602
 603         spin_lock_init(&port->lock);
 604
 605         port->index = vcc_table_add(port);
 606         if (port->index == -1) {
 607                 pr_err("VCC: no more TTY indices left for allocation\n");
 608                 rv = -ENOMEM;
 609                 goto free_ldc;
 610         }
 611
 612         /* Register the device using VCC table index as TTY index */
 613         dev = tty_register_device(vcc_tty_driver, port->index, &vdev->dev);
 614         if (IS_ERR(dev)) {
 615                 rv = PTR_ERR(dev);
 616                 goto free_table;
 617         }
 618
 619         hp = mdesc_grab();
 620
 621         node = vio_vdev_node(hp, vdev);
 622         if (node == MDESC_NODE_NULL) {
 623                 rv = -ENXIO;
 624                 mdesc_release(hp);
 625                 goto unreg_tty;
 626         }
 627
 628         domain = mdesc_get_property(hp, node, "vcc-domain-name", NULL);
 629         if (!domain) {
 630                 rv = -ENXIO;
 631                 mdesc_release(hp);
 632                 goto unreg_tty;
 633         }
 634         port->domain = kstrdup(domain, GFP_KERNEL);
 635
 636         mdesc_release(hp);
 637
 638         rv = sysfs_create_group(&vdev->dev.kobj, &vcc_attribute_group);
 639         if (rv)
 640                 goto free_domain;
 641
 642         timer_setup(&port->rx_timer, vcc_rx_timer, 0);
 643         timer_setup(&port->tx_timer, vcc_tx_timer, 0);
 644
 645         dev_set_drvdata(&vdev->dev, port);
 646
 647         /* It's possible to receive IRQs in the middle of vio_port_up. Disable
 648          * IRQs until the port is up.
 649          */
 650         disable_irq_nosync(vdev->rx_irq);
 651         vio_port_up(&port->vio);
 652         enable_irq(vdev->rx_irq);
 653
 654         return 0;
 655
 656 free_domain:
 657         kfree(port->domain);
 658 unreg_tty:
 659         tty_unregister_device(vcc_tty_driver, port->index);
 660 free_table:
 661         vcc_table_remove(port->index);
 662 free_ldc:
 663         vio_ldc_free(&port->vio);
 664 free_port:
 665         kfree(name);
 666         kfree(port);
 667
 668         return rv;
 669 }
 670
 671 /**
 672  * vcc_remove() - Terminate a VCC port
 673  * @vdev: Pointer to VIO device of the VCC port
 674  *
 675  * Terminates a VCC port. Sets up the teardown of TTY and
 676  * VIO/LDC link between guest and primary domains.
 677  *
 678  * Return: status of removal
 679  */
 680 static int vcc_remove(struct vio_dev *vdev)
 681 {
 682         struct vcc_port *port = dev_get_drvdata(&vdev->dev);
 683
 684         del_timer_sync(&port->rx_timer);
 685         del_timer_sync(&port->tx_timer);
 686
 687         /* If there's a process with the device open, do a synchronous
 688          * hangup of the TTY. This *may* cause the process to call close
 689          * asynchronously, but it's not guaranteed.
 690          */
 691         if (port->tty)
 692                 tty_vhangup(port->tty);
 693
 694         /* Get exclusive reference to VCC, ensures that there are no other
 695          * clients to this port. This cannot fail.
 696          */
 697         vcc_get(port->index, true);
 698
 699         tty_unregister_device(vcc_tty_driver, port->index);
 700
 701         del_timer_sync(&port->vio.timer);
 702         vio_ldc_free(&port->vio);
 703         sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
 704         dev_set_drvdata(&vdev->dev, NULL);
 705         if (port->tty) {
 706                 port->removed = true;
 707                 vcc_put(port, true);
 708         } else {
 709                 vcc_table_remove(port->index);
 710
 711                 kfree(port->vio.name);
 712                 kfree(port->domain);
 713                 kfree(port);
 714         }
 715
 716         return 0;
 717 }
 718
 719 static const struct vio_device_id vcc_match[] = {
 720         {
 721                 .type = "vcc-port",
 722         },
 723         {},
 724 };
 725 MODULE_DEVICE_TABLE(vio, vcc_match);
 726
 727 static struct vio_driver vcc_driver = {
 728         .id_table       = vcc_match,
 729         .probe          = vcc_probe,
 730         .remove         = vcc_remove,
 731         .name           = "vcc",
 732 };
 733
 734 static int vcc_open(struct tty_struct *tty, struct file *vcc_file)
 735 {
 736         struct vcc_port *port;
 737
 738         if (unlikely(!tty)) {
 739                 pr_err("VCC: open: Invalid TTY handle\n");
 740                 return -ENXIO;
 741         }
 742
 743         if (tty->count > 1)
 744                 return -EBUSY;
 745
 746         port = vcc_get_ne(tty->index);
 747         if (unlikely(!port)) {
 748                 pr_err("VCC: open: Failed to find VCC port\n");
 749                 return -ENODEV;
 750         }
 751
 752         if (unlikely(!port->vio.lp)) {
 753                 pr_err("VCC: open: LDC channel not configured\n");
 754                 vcc_put(port, false);
 755                 return -EPIPE;
 756         }
 757         vccdbgl(port->vio.lp);
 758
 759         vcc_put(port, false);
 760
 761         if (unlikely(!tty->port)) {
 762                 pr_err("VCC: open: TTY port not found\n");
 763                 return -ENXIO;
 764         }
 765
 766         if (unlikely(!tty->port->ops)) {
 767                 pr_err("VCC: open: TTY ops not defined\n");
 768                 return -ENXIO;
 769         }
 770
 771         return tty_port_open(tty->port, tty, vcc_file);
 772 }
 773
 774 static void vcc_close(struct tty_struct *tty, struct file *vcc_file)
 775 {
 776         if (unlikely(!tty)) {
 777                 pr_err("VCC: close: Invalid TTY handle\n");
 778                 return;
 779         }
 780
 781         if (unlikely(tty->count > 1))
 782                 return;
 783
 784         if (unlikely(!tty->port)) {
 785                 pr_err("VCC: close: TTY port not found\n");
 786                 return;
 787         }
 788
 789         tty_port_close(tty->port, tty, vcc_file);
 790 }
 791
 792 static void vcc_ldc_hup(struct vcc_port *port)
 793 {
 794         unsigned long flags;
 795
 796         spin_lock_irqsave(&port->lock, flags);
 797
 798         if (vcc_send_ctl(port, VCC_CTL_HUP) < 0)
 799                 vcc_kick_tx(port);
 800
 801         spin_unlock_irqrestore(&port->lock, flags);
 802 }
 803
 804 static void vcc_hangup(struct tty_struct *tty)
 805 {
 806         struct vcc_port *port;
 807
 808         if (unlikely(!tty)) {
 809                 pr_err("VCC: hangup: Invalid TTY handle\n");
 810                 return;
 811         }
 812
 813         port = vcc_get_ne(tty->index);
 814         if (unlikely(!port)) {
 815                 pr_err("VCC: hangup: Failed to find VCC port\n");
 816                 return;
 817         }
 818
 819         if (unlikely(!tty->port)) {
 820                 pr_err("VCC: hangup: TTY port not found\n");
 821                 vcc_put(port, false);
 822                 return;
 823         }
 824
 825         vcc_ldc_hup(port);
 826
 827         vcc_put(port, false);
 828
 829         tty_port_hangup(tty->port);
 830 }
 831
 832 static int vcc_write(struct tty_struct *tty, const unsigned char *buf,
 833                      int count)
 834 {
 835         struct vcc_port *port;
 836         struct vio_vcc *pkt;
 837         unsigned long flags;
 838         int total_sent = 0;
 839         int tosend = 0;
 840         int rv = -EINVAL;
 841
 842         if (unlikely(!tty)) {
 843                 pr_err("VCC: write: Invalid TTY handle\n");
 844                 return -ENXIO;
 845         }
 846
 847         port = vcc_get_ne(tty->index);
 848         if (unlikely(!port)) {
 849                 pr_err("VCC: write: Failed to find VCC port");
 850                 return -ENODEV;
 851         }
 852
 853         spin_lock_irqsave(&port->lock, flags);
 854
 855         pkt = &port->buffer;
 856         pkt->tag.type = VIO_TYPE_DATA;
 857
 858         while (count > 0) {
 859                 /* Minimum of data to write and space available */
 860                 tosend = min(count, (VCC_BUFF_LEN - port->chars_in_buffer));
 861
 862                 if (!tosend)
 863                         break;
 864
 865                 memcpy(&pkt->data[port->chars_in_buffer], &buf[total_sent],
 866                        tosend);
 867                 port->chars_in_buffer += tosend;
 868                 pkt->tag.stype = tosend;
 869
 870                 vccdbg("TAG [%02x:%02x:%04x:%08x]\n", pkt->tag.type,
 871                        pkt->tag.stype, pkt->tag.stype_env, pkt->tag.sid);
 872                 vccdbg("DATA [%s]\n", pkt->data);
 873                 vccdbgl(port->vio.lp);
 874
 875                 /* Since we know we have enough room in VCC buffer for tosend
 876                  * we record that it was sent regardless of whether the
 877                  * hypervisor actually took it because we have it buffered.
 878                  */
 879                 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 880                 vccdbg("VCC: write: ldc_write(%d)=%d\n",
 881                        (VIO_TAG_SIZE + tosend), rv);
 882
 883                 total_sent += tosend;
 884                 count -= tosend;
 885                 if (rv < 0) {
 886                         vcc_kick_tx(port);
 887                         break;
 888                 }
 889
 890                 port->chars_in_buffer = 0;
 891         }
 892
 893         spin_unlock_irqrestore(&port->lock, flags);
 894
 895         vcc_put(port, false);
 896
 897         vccdbg("VCC: write: total=%d rv=%d", total_sent, rv);
 898
 899         return total_sent ? total_sent : rv;
 900 }
 901
 902 static int vcc_write_room(struct tty_struct *tty)
 903 {
 904         struct vcc_port *port;
 905         u64 num;
 906
 907         if (unlikely(!tty)) {
 908                 pr_err("VCC: write_room: Invalid TTY handle\n");
 909                 return -ENXIO;
 910         }
 911
 912         port = vcc_get_ne(tty->index);
 913         if (unlikely(!port)) {
 914                 pr_err("VCC: write_room: Failed to find VCC port\n");
 915                 return -ENODEV;
 916         }
 917
 918         num = VCC_BUFF_LEN - port->chars_in_buffer;
 919
 920         vcc_put(port, false);
 921
 922         return num;
 923 }
 924
 925 static int vcc_chars_in_buffer(struct tty_struct *tty)
 926 {
 927         struct vcc_port *port;
 928         u64 num;
 929
 930         if (unlikely(!tty)) {
 931                 pr_err("VCC: chars_in_buffer: Invalid TTY handle\n");
 932                 return -ENXIO;
 933         }
 934
 935         port = vcc_get_ne(tty->index);
 936         if (unlikely(!port)) {
 937                 pr_err("VCC: chars_in_buffer: Failed to find VCC port\n");
 938                 return -ENODEV;
 939         }
 940
 941         num = port->chars_in_buffer;
 942
 943         vcc_put(port, false);
 944
 945         return num;
 946 }
 947
 948 static int vcc_break_ctl(struct tty_struct *tty, int state)
 949 {
 950         struct vcc_port *port;
 951         unsigned long flags;
 952
 953         if (unlikely(!tty)) {
 954                 pr_err("VCC: break_ctl: Invalid TTY handle\n");
 955                 return -ENXIO;
 956         }
 957
 958         port = vcc_get_ne(tty->index);
 959         if (unlikely(!port)) {
 960                 pr_err("VCC: break_ctl: Failed to find VCC port\n");
 961                 return -ENODEV;
 962         }
 963
 964         /* Turn off break */
 965         if (state == 0) {
 966                 vcc_put(port, false);
 967                 return 0;
 968         }
 969
 970         spin_lock_irqsave(&port->lock, flags);
 971
 972         if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 973                 vcc_kick_tx(port);
 974
 975         spin_unlock_irqrestore(&port->lock, flags);
 976
 977         vcc_put(port, false);
 978
 979         return 0;
 980 }
 981
 982 static int vcc_install(struct tty_driver *driver, struct tty_struct *tty)
 983 {
 984         struct vcc_port *port_vcc;
 985         struct tty_port *port_tty;
 986         int ret;
 987
 988         if (unlikely(!tty)) {
 989                 pr_err("VCC: install: Invalid TTY handle\n");
 990                 return -ENXIO;
 991         }
 992
 993         if (tty->index >= VCC_MAX_PORTS)
 994                 return -EINVAL;
 995
 996         ret = tty_standard_install(driver, tty);
 997         if (ret)
 998                 return ret;
 999
1000         port_tty = kzalloc(sizeof(struct tty_port), GFP_KERNEL);
1001         if (!port_tty)
1002                 return -ENOMEM;
1003
1004         port_vcc = vcc_get(tty->index, true);
1005         if (!port_vcc) {
1006                 pr_err("VCC: install: Failed to find VCC port\n");
1007                 tty->port = NULL;
1008                 kfree(port_tty);
1009                 return -ENODEV;
1010         }
1011
1012         tty_port_init(port_tty);
1013         port_tty->ops = &vcc_port_ops;
1014         tty->port = port_tty;
1015
1016         port_vcc->tty = tty;
1017
1018         vcc_put(port_vcc, true);
1019
1020         return 0;
1021 }
1022
1023 static void vcc_cleanup(struct tty_struct *tty)
1024 {
1025         struct vcc_port *port;
1026
1027         if (unlikely(!tty)) {
1028                 pr_err("VCC: cleanup: Invalid TTY handle\n");
1029                 return;
1030         }
1031
1032         port = vcc_get(tty->index, true);
1033         if (port) {
1034                 port->tty = NULL;
1035
1036                 if (port->removed) {
1037                         vcc_table_remove(tty->index);
1038                         kfree(port->vio.name);
1039                         kfree(port->domain);
1040                         kfree(port);
1041                 } else {
1042                         vcc_put(port, true);
1043                 }
1044         }
1045
1046         tty_port_destroy(tty->port);
1047         kfree(tty->port);
1048         tty->port = NULL;
1049 }
1050
1051 static const struct tty_operations vcc_ops = {
1052         .open                   = vcc_open,
1053         .close                  = vcc_close,
1054         .hangup                 = vcc_hangup,
1055         .write                  = vcc_write,
1056         .write_room             = vcc_write_room,
1057         .chars_in_buffer        = vcc_chars_in_buffer,
1058         .break_ctl              = vcc_break_ctl,
1059         .install                = vcc_install,
1060         .cleanup                = vcc_cleanup,
1061 };
1062
1063 #define VCC_TTY_FLAGS   (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
1064
1065 static int vcc_tty_init(void)
1066 {
1067         int rv;
1068
1069         pr_info("VCC: %s\n", version);
1070
1071         vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
1072         if (IS_ERR(vcc_tty_driver)) {
1073                 pr_err("VCC: TTY driver alloc failed\n");
1074                 return PTR_ERR(vcc_tty_driver);
1075         }
1076
1077         vcc_tty_driver->driver_name = vcc_driver_name;
1078         vcc_tty_driver->name = vcc_device_node;
1079
1080         vcc_tty_driver->minor_start = VCC_MINOR_START;
1081         vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1082         vcc_tty_driver->init_termios = vcc_tty_termios;
1083
1084         tty_set_operations(vcc_tty_driver, &vcc_ops);
1085
1086         rv = tty_register_driver(vcc_tty_driver);
1087         if (rv) {
1088                 pr_err("VCC: TTY driver registration failed\n");
1089                 put_tty_driver(vcc_tty_driver);
1090                 vcc_tty_driver = NULL;
1091                 return rv;
1092         }
1093
1094         vccdbg("VCC: TTY driver registered\n");
1095
1096         return 0;
1097 }
1098
1099 static void vcc_tty_exit(void)
1100 {
1101         tty_unregister_driver(vcc_tty_driver);
1102         put_tty_driver(vcc_tty_driver);
1103         vccdbg("VCC: TTY driver unregistered\n");
1104
1105         vcc_tty_driver = NULL;
1106 }
1107
1108 static int __init vcc_init(void)
1109 {
1110         int rv;
1111
1112         rv = vcc_tty_init();
1113         if (rv) {
1114                 pr_err("VCC: TTY init failed\n");
1115                 return rv;
1116         }
1117
1118         rv = vio_register_driver(&vcc_driver);
1119         if (rv) {
1120                 pr_err("VCC: VIO driver registration failed\n");
1121                 vcc_tty_exit();
1122         } else {
1123                 vccdbg("VCC: VIO driver registered successfully\n");
1124         }
1125
1126         return rv;
1127 }
1128
1129 static void __exit vcc_exit(void)
1130 {
1131         vio_unregister_driver(&vcc_driver);
1132         vccdbg("VCC: VIO driver unregistered\n");
1133         vcc_tty_exit();
1134         vccdbg("VCC: TTY driver unregistered\n");
1135 }
1136
1137 module_init(vcc_init);
1138 module_exit(vcc_exit);