drivers/tty/vcc.c

   1 /* vcc.c: sun4v virtual channel concentrator
   2  *
   3  * Copyright (C) 2017 Oracle. All rights reserved.
   4  */
   5
   6 #include <linux/delay.h>
   7 #include <linux/interrupt.h>
   8 #include <linux/module.h>
   9 #include <linux/slab.h>
  10 #include <linux/sysfs.h>
  11 #include <linux/tty.h>
  12 #include <linux/tty_flip.h>
  13 #include <asm/vio.h>
  14 #include <asm/ldc.h>
  15
  16 #define DRV_MODULE_NAME         "vcc"
  17 #define DRV_MODULE_VERSION      "1.1"
  18 #define DRV_MODULE_RELDATE      "July 1, 2017"
  19
  20 static char version[] =
  21         DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")";
  22
  23 MODULE_DESCRIPTION("Sun LDOM virtual console concentrator driver");
  24 MODULE_LICENSE("GPL");
  25 MODULE_VERSION(DRV_MODULE_VERSION);
  26
  27 struct vcc_port {
  28         struct vio_driver_state vio;
  29
  30         spinlock_t lock;
  31         char *domain;
  32         struct tty_struct *tty; /* only populated while dev is open */
  33         unsigned long index;    /* index into the vcc_table */
  34
  35         u64 refcnt;
  36         bool excl_locked;
  37
  38         bool removed;
  39
  40         /* This buffer is required to support the tty write_room interface
  41          * and guarantee that any characters that the driver accepts will
  42          * be eventually sent, either immediately or later.
  43          */
  44         int chars_in_buffer;
  45         struct vio_vcc buffer;
  46
  47         struct timer_list rx_timer;
  48         struct timer_list tx_timer;
  49 };
  50
  51 /* Microseconds that thread will delay waiting for a vcc port ref */
  52 #define VCC_REF_DELAY           100
  53
  54 #define VCC_MAX_PORTS           1024
  55 #define VCC_MINOR_START         0       /* must be zero */
  56 #define VCC_BUFF_LEN            VIO_VCC_MTU_SIZE
  57
  58 #define VCC_CTL_BREAK           -1
  59 #define VCC_CTL_HUP             -2
  60
  61 static const char vcc_driver_name[] = "vcc";
  62 static const char vcc_device_node[] = "vcc";
  63 static struct tty_driver *vcc_tty_driver;
  64
  65 static struct vcc_port *vcc_table[VCC_MAX_PORTS];
  66 static DEFINE_SPINLOCK(vcc_table_lock);
  67
  68 int vcc_dbg;
  69 int vcc_dbg_ldc;
  70 int vcc_dbg_vio;
  71
  72 module_param(vcc_dbg, uint, 0664);
  73 module_param(vcc_dbg_ldc, uint, 0664);
  74 module_param(vcc_dbg_vio, uint, 0664);
  75
  76 #define VCC_DBG_DRV     0x1
  77 #define VCC_DBG_LDC     0x2
  78 #define VCC_DBG_PKT     0x4
  79
  80 #define vccdbg(f, a...)                                         \
  81         do {                                                    \
  82                 if (vcc_dbg & VCC_DBG_DRV)                      \
  83                         pr_info(f, ## a);                       \
  84         } while (0)                                             \
  85
  86 #define vccdbgl(l)                                              \
  87         do {                                                    \
  88                 if (vcc_dbg & VCC_DBG_LDC)                      \
  89                         ldc_print(l);                           \
  90         } while (0)                                             \
  91
  92 #define vccdbgp(pkt)                                            \
  93         do {                                                    \
  94                 if (vcc_dbg & VCC_DBG_PKT) {                    \
  95                         int i;                                  \
  96                         for (i = 0; i < pkt.tag.stype; i++)     \
  97                                 pr_info("[%c]", pkt.data[i]);   \
  98                 }                                               \
  99         } while (0)                                             \
 100
 101 /* Note: Be careful when adding flags to this line discipline.  Don't
 102  * add anything that will cause echoing or we'll go into recursive
 103  * loop echoing chars back and forth with the console drivers.
 104  */
 105 static const struct ktermios vcc_tty_termios = {
 106         .c_iflag = IGNBRK | IGNPAR,
 107         .c_oflag = OPOST,
 108         .c_cflag = B38400 | CS8 | CREAD | HUPCL,
 109         .c_cc = INIT_C_CC,
 110         .c_ispeed = 38400,
 111         .c_ospeed = 38400
 112 };
 113
 114 /**
 115  * vcc_table_add() - Add VCC port to the VCC table
 116  * @port: pointer to the VCC port
 117  *
 118  * Return: index of the port in the VCC table on success,
 119  *         -1 on failure
 120  */
 121 static int vcc_table_add(struct vcc_port *port)
 122 {
 123         unsigned long flags;
 124         int i;
 125
 126         spin_lock_irqsave(&vcc_table_lock, flags);
 127         for (i = VCC_MINOR_START; i < VCC_MAX_PORTS; i++) {
 128                 if (!vcc_table[i]) {
 129                         vcc_table[i] = port;
 130                         break;
 131                 }
 132         }
 133         spin_unlock_irqrestore(&vcc_table_lock, flags);
 134
 135         if (i < VCC_MAX_PORTS)
 136                 return i;
 137         else
 138                 return -1;
 139 }
 140
 141 /**
 142  * vcc_table_remove() - Removes a VCC port from the VCC table
 143  * @index: Index into the VCC table
 144  */
 145 static void vcc_table_remove(unsigned long index)
 146 {
 147         unsigned long flags;
 148
 149         if (WARN_ON(index >= VCC_MAX_PORTS))
 150                 return;
 151
 152         spin_lock_irqsave(&vcc_table_lock, flags);
 153         vcc_table[index] = NULL;
 154         spin_unlock_irqrestore(&vcc_table_lock, flags);
 155 }
 156
 157 /**
 158  * vcc_get() - Gets a reference to VCC port
 159  * @index: Index into the VCC table
 160  * @excl: Indicates if an exclusive access is requested
 161  *
 162  * Return: reference to the VCC port, if found
 163  *         NULL, if port not found
 164  */
 165 static struct vcc_port *vcc_get(unsigned long index, bool excl)
 166 {
 167         struct vcc_port *port;
 168         unsigned long flags;
 169
 170 try_again:
 171         spin_lock_irqsave(&vcc_table_lock, flags);
 172
 173         port = vcc_table[index];
 174         if (!port) {
 175                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 176                 return NULL;
 177         }
 178
 179         if (!excl) {
 180                 if (port->excl_locked) {
 181                         spin_unlock_irqrestore(&vcc_table_lock, flags);
 182                         udelay(VCC_REF_DELAY);
 183                         goto try_again;
 184                 }
 185                 port->refcnt++;
 186                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 187                 return port;
 188         }
 189
 190         if (port->refcnt) {
 191                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 192                 /* Threads wanting exclusive access will wait half the time,
 193                  * probably giving them higher priority in the case of
 194                  * multiple waiters.
 195                  */
 196                 udelay(VCC_REF_DELAY/2);
 197                 goto try_again;
 198         }
 199
 200         port->refcnt++;
 201         port->excl_locked = true;
 202         spin_unlock_irqrestore(&vcc_table_lock, flags);
 203
 204         return port;
 205 }
 206
 207 /**
 208  * vcc_put() - Returns a reference to VCC port
 209  * @port: pointer to VCC port
 210  * @excl: Indicates if the returned reference is an exclusive reference
 211  *
 212  * Note: It's the caller's responsibility to ensure the correct value
 213  *       for the excl flag
 214  */
 215 static void vcc_put(struct vcc_port *port, bool excl)
 216 {
 217         unsigned long flags;
 218
 219         if (!port)
 220                 return;
 221
 222         spin_lock_irqsave(&vcc_table_lock, flags);
 223
 224         /* check if caller attempted to put with the wrong flags */
 225         if (WARN_ON((excl && !port->excl_locked) ||
 226                     (!excl && port->excl_locked)))
 227                 goto done;
 228
 229         port->refcnt--;
 230
 231         if (excl)
 232                 port->excl_locked = false;
 233
 234 done:
 235         spin_unlock_irqrestore(&vcc_table_lock, flags);
 236 }
 237
 238 /**
 239  * vcc_get_ne() - Get a non-exclusive reference to VCC port
 240  * @index: Index into the VCC table
 241  *
 242  * Gets a non-exclusive reference to VCC port, if it's not removed
 243  *
 244  * Return: pointer to the VCC port, if found
 245  *         NULL, if port not found
 246  */
 247 static struct vcc_port *vcc_get_ne(unsigned long index)
 248 {
 249         struct vcc_port *port;
 250
 251         port = vcc_get(index, false);
 252
 253         if (port && port->removed) {
 254                 vcc_put(port, false);
 255                 return NULL;
 256         }
 257
 258         return port;
 259 }
 260
 261 static void vcc_kick_rx(struct vcc_port *port)
 262 {
 263         struct vio_driver_state *vio = &port->vio;
 264
 265         assert_spin_locked(&port->lock);
 266
 267         if (!timer_pending(&port->rx_timer) && !port->removed) {
 268                 disable_irq_nosync(vio->vdev->rx_irq);
 269                 port->rx_timer.expires = (jiffies + 1);
 270                 add_timer(&port->rx_timer);
 271         }
 272 }
 273
 274 static void vcc_kick_tx(struct vcc_port *port)
 275 {
 276         assert_spin_locked(&port->lock);
 277
 278         if (!timer_pending(&port->tx_timer) && !port->removed) {
 279                 port->tx_timer.expires = (jiffies + 1);
 280                 add_timer(&port->tx_timer);
 281         }
 282 }
 283
 284 static int vcc_rx_check(struct tty_struct *tty, int size)
 285 {
 286         if (WARN_ON(!tty || !tty->port))
 287                 return 1;
 288
 289         /* tty_buffer_request_room won't sleep because it uses
 290          * GFP_ATOMIC flag to allocate buffer
 291          */
 292         if (test_bit(TTY_THROTTLED, &tty->flags) ||
 293             (tty_buffer_request_room(tty->port, VCC_BUFF_LEN) < VCC_BUFF_LEN))
 294                 return 0;
 295
 296         return 1;
 297 }
 298
 299 static int vcc_rx(struct tty_struct *tty, char *buf, int size)
 300 {
 301         int len = 0;
 302
 303         if (WARN_ON(!tty || !tty->port))
 304                 return len;
 305
 306         len = tty_insert_flip_string(tty->port, buf, size);
 307         if (len)
 308                 tty_flip_buffer_push(tty->port);
 309
 310         return len;
 311 }
 312
 313 static int vcc_ldc_read(struct vcc_port *port)
 314 {
 315         struct vio_driver_state *vio = &port->vio;
 316         struct tty_struct *tty;
 317         struct vio_vcc pkt;
 318         int rv = 0;
 319
 320         tty = port->tty;
 321         if (!tty) {
 322                 rv = ldc_rx_reset(vio->lp);
 323                 vccdbg("VCC: reset rx q: rv=%d\n", rv);
 324                 goto done;
 325         }
 326
 327         /* Read as long as LDC has incoming data. */
 328         while (1) {
 329                 if (!vcc_rx_check(tty, VIO_VCC_MTU_SIZE)) {
 330                         vcc_kick_rx(port);
 331                         break;
 332                 }
 333
 334                 vccdbgl(vio->lp);
 335
 336                 rv = ldc_read(vio->lp, &pkt, sizeof(pkt));
 337                 if (rv <= 0)
 338                         break;
 339
 340                 vccdbg("VCC: ldc_read()=%d\n", rv);
 341                 vccdbg("TAG [%02x:%02x:%04x:%08x]\n",
 342                        pkt.tag.type, pkt.tag.stype,
 343                        pkt.tag.stype_env, pkt.tag.sid);
 344
 345                 if (pkt.tag.type == VIO_TYPE_DATA) {
 346                         vccdbgp(pkt);
 347                         /* vcc_rx_check ensures memory availability */
 348                         vcc_rx(tty, pkt.data, pkt.tag.stype);
 349                 } else {
 350                         pr_err("VCC: unknown msg [%02x:%02x:%04x:%08x]\n",
 351                                pkt.tag.type, pkt.tag.stype,
 352                                pkt.tag.stype_env, pkt.tag.sid);
 353                         rv = -ECONNRESET;
 354                         break;
 355                 }
 356
 357                 WARN_ON(rv != LDC_PACKET_SIZE);
 358         }
 359
 360 done:
 361         return rv;
 362 }
 363
 364 static void vcc_rx_timer(struct timer_list *t)
 365 {
 366         struct vcc_port *port = from_timer(port, t, rx_timer);
 367         struct vio_driver_state *vio;
 368         unsigned long flags;
 369         int rv;
 370
 371         spin_lock_irqsave(&port->lock, flags);
 372         port->rx_timer.expires = 0;
 373
 374         vio = &port->vio;
 375
 376         enable_irq(vio->vdev->rx_irq);
 377
 378         if (!port->tty || port->removed)
 379                 goto done;
 380
 381         rv = vcc_ldc_read(port);
 382         if (rv == -ECONNRESET)
 383                 vio_conn_reset(vio);
 384
 385 done:
 386         spin_unlock_irqrestore(&port->lock, flags);
 387         vcc_put(port, false);
 388 }
 389
 390 static void vcc_tx_timer(struct timer_list *t)
 391 {
 392         struct vcc_port *port = from_timer(port, t, tx_timer);
 393         struct vio_vcc *pkt;
 394         unsigned long flags;
 395         int tosend = 0;
 396         int rv;
 397
 398         spin_lock_irqsave(&port->lock, flags);
 399         port->tx_timer.expires = 0;
 400
 401         if (!port->tty || port->removed)
 402                 goto done;
 403
 404         tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
 405         if (!tosend)
 406                 goto done;
 407
 408         pkt = &port->buffer;
 409         pkt->tag.type = VIO_TYPE_DATA;
 410         pkt->tag.stype = tosend;
 411         vccdbgl(port->vio.lp);
 412
 413         rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 414         WARN_ON(!rv);
 415
 416         if (rv < 0) {
 417                 vccdbg("VCC: ldc_write()=%d\n", rv);
 418                 vcc_kick_tx(port);
 419         } else {
 420                 struct tty_struct *tty = port->tty;
 421
 422                 port->chars_in_buffer = 0;
 423                 if (tty)
 424                         tty_wakeup(tty);
 425         }
 426
 427 done:
 428         spin_unlock_irqrestore(&port->lock, flags);
 429         vcc_put(port, false);
 430 }
 431
 432 /**
 433  * vcc_event() - LDC event processing engine
 434  * @arg: VCC private data
 435  * @event: LDC event
 436  *
 437  * Handles LDC events for VCC
 438  */
 439 static void vcc_event(void *arg, int event)
 440 {
 441         struct vio_driver_state *vio;
 442         struct vcc_port *port;
 443         unsigned long flags;
 444         int rv;
 445
 446         port = arg;
 447         vio = &port->vio;
 448
 449         spin_lock_irqsave(&port->lock, flags);
 450
 451         switch (event) {
 452         case LDC_EVENT_RESET:
 453         case LDC_EVENT_UP:
 454                 vio_link_state_change(vio, event);
 455                 break;
 456
 457         case LDC_EVENT_DATA_READY:
 458                 rv = vcc_ldc_read(port);
 459                 if (rv == -ECONNRESET)
 460                         vio_conn_reset(vio);
 461                 break;
 462
 463         default:
 464                 pr_err("VCC: unexpected LDC event(%d)\n", event);
 465         }
 466
 467         spin_unlock_irqrestore(&port->lock, flags);
 468 }
 469
 470 static struct ldc_channel_config vcc_ldc_cfg = {
 471         .event          = vcc_event,
 472         .mtu            = VIO_VCC_MTU_SIZE,
 473         .mode           = LDC_MODE_RAW,
 474         .debug          = 0,
 475 };
 476
 477 /* Ordered from largest major to lowest */
 478 static struct vio_version vcc_versions[] = {
 479         { .major = 1, .minor = 0 },
 480 };
 481
 482 static struct tty_port_operations vcc_port_ops = { 0 };
 483
 484 static ssize_t vcc_sysfs_domain_show(struct device *dev,
 485                                      struct device_attribute *attr,
 486                                      char *buf)
 487 {
 488         struct vcc_port *port;
 489         int rv;
 490
 491         port = dev_get_drvdata(dev);
 492         if (!port)
 493                 return -ENODEV;
 494
 495         rv = scnprintf(buf, PAGE_SIZE, "%s\n", port->domain);
 496
 497         return rv;
 498 }
 499
 500 static int vcc_send_ctl(struct vcc_port *port, int ctl)
 501 {
 502         struct vio_vcc pkt;
 503         int rv;
 504
 505         pkt.tag.type = VIO_TYPE_CTRL;
 506         pkt.tag.sid = ctl;
 507         pkt.tag.stype = 0;
 508
 509         rv = ldc_write(port->vio.lp, &pkt, sizeof(pkt.tag));
 510         WARN_ON(!rv);
 511         vccdbg("VCC: ldc_write(%ld)=%d\n", sizeof(pkt.tag), rv);
 512
 513         return rv;
 514 }
 515
 516 static ssize_t vcc_sysfs_break_store(struct device *dev,
 517                                      struct device_attribute *attr,
 518                                      const char *buf, size_t count)
 519 {
 520         struct vcc_port *port;
 521         unsigned long flags;
 522         int rv = count;
 523         int brk;
 524
 525         port = dev_get_drvdata(dev);
 526         if (!port)
 527                 return -ENODEV;
 528
 529         spin_lock_irqsave(&port->lock, flags);
 530
 531         if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
 532                 rv = -EINVAL;
 533         else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 534                 vcc_kick_tx(port);
 535
 536         spin_unlock_irqrestore(&port->lock, flags);
 537
 538         return rv;
 539 }
 540
 541 static DEVICE_ATTR(domain, 0400, vcc_sysfs_domain_show, NULL);
 542 static DEVICE_ATTR(break, 0200, NULL, vcc_sysfs_break_store);
 543
 544 static struct attribute *vcc_sysfs_entries[] = {
 545         &dev_attr_domain.attr,
 546         &dev_attr_break.attr,
 547         NULL
 548 };
 549
 550 static struct attribute_group vcc_attribute_group = {
 551         .name = NULL,
 552         .attrs = vcc_sysfs_entries,
 553 };
 554
 555 /**
 556  * vcc_probe() - Initialize VCC port
 557  * @vdev: Pointer to VIO device of the new VCC port
 558  * @id: VIO device ID
 559  *
 560  * Initializes a VCC port to receive serial console data from
 561  * the guest domain. Sets up a TTY end point on the control
 562  * domain. Sets up VIO/LDC link between the guest & control
 563  * domain endpoints.
 564  *
 565  * Return: status of the probe
 566  */
 567 static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 568 {
 569         struct mdesc_handle *hp;
 570         struct vcc_port *port;
 571         struct device *dev;
 572         const char *domain;
 573         char *name;
 574         u64 node;
 575         int rv;
 576
 577         vccdbg("VCC: name=%s\n", dev_name(&vdev->dev));
 578
 579         if (!vcc_tty_driver) {
 580                 pr_err("VCC: TTY driver not registered\n");
 581                 return -ENODEV;
 582         }
 583
 584         port = kzalloc(sizeof(struct vcc_port), GFP_KERNEL);
 585         if (!port)
 586                 return -ENOMEM;
 587
 588         name = kstrdup(dev_name(&vdev->dev), GFP_KERNEL);
 589
 590         rv = vio_driver_init(&port->vio, vdev, VDEV_CONSOLE_CON, vcc_versions,
 591                              ARRAY_SIZE(vcc_versions), NULL, name);
 592         if (rv)
 593                 goto free_port;
 594
 595         port->vio.debug = vcc_dbg_vio;
 596         vcc_ldc_cfg.debug = vcc_dbg_ldc;
 597
 598         rv = vio_ldc_alloc(&port->vio, &vcc_ldc_cfg, port);
 599         if (rv)
 600                 goto free_port;
 601
 602         spin_lock_init(&port->lock);
 603
 604         port->index = vcc_table_add(port);
 605         if (port->index == -1) {
 606                 pr_err("VCC: no more TTY indices left for allocation\n");
 607                 goto free_ldc;
 608         }
 609
 610         /* Register the device using VCC table index as TTY index */
 611         dev = tty_register_device(vcc_tty_driver, port->index, &vdev->dev);
 612         if (IS_ERR(dev)) {
 613                 rv = PTR_ERR(dev);
 614                 goto free_table;
 615         }
 616
 617         hp = mdesc_grab();
 618
 619         node = vio_vdev_node(hp, vdev);
 620         if (node == MDESC_NODE_NULL) {
 621                 rv = -ENXIO;
 622                 mdesc_release(hp);
 623                 goto unreg_tty;
 624         }
 625
 626         domain = mdesc_get_property(hp, node, "vcc-domain-name", NULL);
 627         if (!domain) {
 628                 rv = -ENXIO;
 629                 mdesc_release(hp);
 630                 goto unreg_tty;
 631         }
 632         port->domain = kstrdup(domain, GFP_KERNEL);
 633
 634         mdesc_release(hp);
 635
 636         rv = sysfs_create_group(&vdev->dev.kobj, &vcc_attribute_group);
 637         if (rv)
 638                 goto free_domain;
 639
 640         timer_setup(&port->rx_timer, vcc_rx_timer, 0);
 641         timer_setup(&port->tx_timer, vcc_tx_timer, 0);
 642
 643         dev_set_drvdata(&vdev->dev, port);
 644
 645         /* It's possible to receive IRQs in the middle of vio_port_up. Disable
 646          * IRQs until the port is up.
 647          */
 648         disable_irq_nosync(vdev->rx_irq);
 649         vio_port_up(&port->vio);
 650         enable_irq(vdev->rx_irq);
 651
 652         return 0;
 653
 654 free_domain:
 655         kfree(port->domain);
 656 unreg_tty:
 657         tty_unregister_device(vcc_tty_driver, port->index);
 658 free_table:
 659         vcc_table_remove(port->index);
 660 free_ldc:
 661         vio_ldc_free(&port->vio);
 662 free_port:
 663         kfree(name);
 664         kfree(port);
 665
 666         return rv;
 667 }
 668
 669 /**
 670  * vcc_remove() - Terminate a VCC port
 671  * @vdev: Pointer to VIO device of the VCC port
 672  *
 673  * Terminates a VCC port. Sets up the teardown of TTY and
 674  * VIO/LDC link between guest and primary domains.
 675  *
 676  * Return: status of removal
 677  */
 678 static int vcc_remove(struct vio_dev *vdev)
 679 {
 680         struct vcc_port *port = dev_get_drvdata(&vdev->dev);
 681
 682         if (!port)
 683                 return -ENODEV;
 684
 685         del_timer_sync(&port->rx_timer);
 686         del_timer_sync(&port->tx_timer);
 687
 688         /* If there's a process with the device open, do a synchronous
 689          * hangup of the TTY. This *may* cause the process to call close
 690          * asynchronously, but it's not guaranteed.
 691          */
 692         if (port->tty)
 693                 tty_vhangup(port->tty);
 694
 695         /* Get exclusive reference to VCC, ensures that there are no other
 696          * clients to this port
 697          */
 698         port = vcc_get(port->index, true);
 699
 700         if (WARN_ON(!port))
 701                 return -ENODEV;
 702
 703         tty_unregister_device(vcc_tty_driver, port->index);
 704
 705         del_timer_sync(&port->vio.timer);
 706         vio_ldc_free(&port->vio);
 707         sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
 708         dev_set_drvdata(&vdev->dev, NULL);
 709         if (port->tty) {
 710                 port->removed = true;
 711                 vcc_put(port, true);
 712         } else {
 713                 vcc_table_remove(port->index);
 714
 715                 kfree(port->vio.name);
 716                 kfree(port->domain);
 717                 kfree(port);
 718         }
 719
 720         return 0;
 721 }
 722
 723 static const struct vio_device_id vcc_match[] = {
 724         {
 725                 .type = "vcc-port",
 726         },
 727         {},
 728 };
 729 MODULE_DEVICE_TABLE(vio, vcc_match);
 730
 731 static struct vio_driver vcc_driver = {
 732         .id_table       = vcc_match,
 733         .probe          = vcc_probe,
 734         .remove         = vcc_remove,
 735         .name           = "vcc",
 736 };
 737
 738 static int vcc_open(struct tty_struct *tty, struct file *vcc_file)
 739 {
 740         struct vcc_port *port;
 741
 742         if (unlikely(!tty)) {
 743                 pr_err("VCC: open: Invalid TTY handle\n");
 744                 return -ENXIO;
 745         }
 746
 747         if (tty->count > 1)
 748                 return -EBUSY;
 749
 750         port = vcc_get_ne(tty->index);
 751         if (unlikely(!port)) {
 752                 pr_err("VCC: open: Failed to find VCC port\n");
 753                 return -ENODEV;
 754         }
 755
 756         if (unlikely(!port->vio.lp)) {
 757                 pr_err("VCC: open: LDC channel not configured\n");
 758                 vcc_put(port, false);
 759                 return -EPIPE;
 760         }
 761         vccdbgl(port->vio.lp);
 762
 763         vcc_put(port, false);
 764
 765         if (unlikely(!tty->port)) {
 766                 pr_err("VCC: open: TTY port not found\n");
 767                 return -ENXIO;
 768         }
 769
 770         if (unlikely(!tty->port->ops)) {
 771                 pr_err("VCC: open: TTY ops not defined\n");
 772                 return -ENXIO;
 773         }
 774
 775         return tty_port_open(tty->port, tty, vcc_file);
 776 }
 777
 778 static void vcc_close(struct tty_struct *tty, struct file *vcc_file)
 779 {
 780         if (unlikely(!tty)) {
 781                 pr_err("VCC: close: Invalid TTY handle\n");
 782                 return;
 783         }
 784
 785         if (unlikely(tty->count > 1))
 786                 return;
 787
 788         if (unlikely(!tty->port)) {
 789                 pr_err("VCC: close: TTY port not found\n");
 790                 return;
 791         }
 792
 793         tty_port_close(tty->port, tty, vcc_file);
 794 }
 795
 796 static void vcc_ldc_hup(struct vcc_port *port)
 797 {
 798         unsigned long flags;
 799
 800         spin_lock_irqsave(&port->lock, flags);
 801
 802         if (vcc_send_ctl(port, VCC_CTL_HUP) < 0)
 803                 vcc_kick_tx(port);
 804
 805         spin_unlock_irqrestore(&port->lock, flags);
 806 }
 807
 808 static void vcc_hangup(struct tty_struct *tty)
 809 {
 810         struct vcc_port *port;
 811
 812         if (unlikely(!tty)) {
 813                 pr_err("VCC: hangup: Invalid TTY handle\n");
 814                 return;
 815         }
 816
 817         port = vcc_get_ne(tty->index);
 818         if (unlikely(!port)) {
 819                 pr_err("VCC: hangup: Failed to find VCC port\n");
 820                 return;
 821         }
 822
 823         if (unlikely(!tty->port)) {
 824                 pr_err("VCC: hangup: TTY port not found\n");
 825                 vcc_put(port, false);
 826                 return;
 827         }
 828
 829         vcc_ldc_hup(port);
 830
 831         vcc_put(port, false);
 832
 833         tty_port_hangup(tty->port);
 834 }
 835
 836 static int vcc_write(struct tty_struct *tty, const unsigned char *buf,
 837                      int count)
 838 {
 839         struct vcc_port *port;
 840         struct vio_vcc *pkt;
 841         unsigned long flags;
 842         int total_sent = 0;
 843         int tosend = 0;
 844         int rv = -EINVAL;
 845
 846         if (unlikely(!tty)) {
 847                 pr_err("VCC: write: Invalid TTY handle\n");
 848                 return -ENXIO;
 849         }
 850
 851         port = vcc_get_ne(tty->index);
 852         if (unlikely(!port)) {
 853                 pr_err("VCC: write: Failed to find VCC port");
 854                 return -ENODEV;
 855         }
 856
 857         spin_lock_irqsave(&port->lock, flags);
 858
 859         pkt = &port->buffer;
 860         pkt->tag.type = VIO_TYPE_DATA;
 861
 862         while (count > 0) {
 863                 /* Minimum of data to write and space available */
 864                 tosend = min(count, (VCC_BUFF_LEN - port->chars_in_buffer));
 865
 866                 if (!tosend)
 867                         break;
 868
 869                 memcpy(&pkt->data[port->chars_in_buffer], &buf[total_sent],
 870                        tosend);
 871                 port->chars_in_buffer += tosend;
 872                 pkt->tag.stype = tosend;
 873
 874                 vccdbg("TAG [%02x:%02x:%04x:%08x]\n", pkt->tag.type,
 875                        pkt->tag.stype, pkt->tag.stype_env, pkt->tag.sid);
 876                 vccdbg("DATA [%s]\n", pkt->data);
 877                 vccdbgl(port->vio.lp);
 878
 879                 /* Since we know we have enough room in VCC buffer for tosend
 880                  * we record that it was sent regardless of whether the
 881                  * hypervisor actually took it because we have it buffered.
 882                  */
 883                 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 884                 vccdbg("VCC: write: ldc_write(%d)=%d\n",
 885                        (VIO_TAG_SIZE + tosend), rv);
 886
 887                 total_sent += tosend;
 888                 count -= tosend;
 889                 if (rv < 0) {
 890                         vcc_kick_tx(port);
 891                         break;
 892                 }
 893
 894                 port->chars_in_buffer = 0;
 895         }
 896
 897         spin_unlock_irqrestore(&port->lock, flags);
 898
 899         vcc_put(port, false);
 900
 901         vccdbg("VCC: write: total=%d rv=%d", total_sent, rv);
 902
 903         return total_sent ? total_sent : rv;
 904 }
 905
 906 static int vcc_write_room(struct tty_struct *tty)
 907 {
 908         struct vcc_port *port;
 909         u64 num;
 910
 911         if (unlikely(!tty)) {
 912                 pr_err("VCC: write_room: Invalid TTY handle\n");
 913                 return -ENXIO;
 914         }
 915
 916         port = vcc_get_ne(tty->index);
 917         if (unlikely(!port)) {
 918                 pr_err("VCC: write_room: Failed to find VCC port\n");
 919                 return -ENODEV;
 920         }
 921
 922         num = VCC_BUFF_LEN - port->chars_in_buffer;
 923
 924         vcc_put(port, false);
 925
 926         return num;
 927 }
 928
 929 static int vcc_chars_in_buffer(struct tty_struct *tty)
 930 {
 931         struct vcc_port *port;
 932         u64 num;
 933
 934         if (unlikely(!tty)) {
 935                 pr_err("VCC: chars_in_buffer: Invalid TTY handle\n");
 936                 return -ENXIO;
 937         }
 938
 939         port = vcc_get_ne(tty->index);
 940         if (unlikely(!port)) {
 941                 pr_err("VCC: chars_in_buffer: Failed to find VCC port\n");
 942                 return -ENODEV;
 943         }
 944
 945         num = port->chars_in_buffer;
 946
 947         vcc_put(port, false);
 948
 949         return num;
 950 }
 951
 952 static int vcc_break_ctl(struct tty_struct *tty, int state)
 953 {
 954         struct vcc_port *port;
 955         unsigned long flags;
 956
 957         if (unlikely(!tty)) {
 958                 pr_err("VCC: break_ctl: Invalid TTY handle\n");
 959                 return -ENXIO;
 960         }
 961
 962         port = vcc_get_ne(tty->index);
 963         if (unlikely(!port)) {
 964                 pr_err("VCC: break_ctl: Failed to find VCC port\n");
 965                 return -ENODEV;
 966         }
 967
 968         /* Turn off break */
 969         if (state == 0) {
 970                 vcc_put(port, false);
 971                 return 0;
 972         }
 973
 974         spin_lock_irqsave(&port->lock, flags);
 975
 976         if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 977                 vcc_kick_tx(port);
 978
 979         spin_unlock_irqrestore(&port->lock, flags);
 980
 981         vcc_put(port, false);
 982
 983         return 0;
 984 }
 985
 986 static int vcc_install(struct tty_driver *driver, struct tty_struct *tty)
 987 {
 988         struct vcc_port *port_vcc;
 989         struct tty_port *port_tty;
 990         int ret;
 991
 992         if (unlikely(!tty)) {
 993                 pr_err("VCC: install: Invalid TTY handle\n");
 994                 return -ENXIO;
 995         }
 996
 997         if (tty->index >= VCC_MAX_PORTS)
 998                 return -EINVAL;
 999
1000         ret = tty_standard_install(driver, tty);
1001         if (ret)
1002                 return ret;
1003
1004         port_tty = kzalloc(sizeof(struct tty_port), GFP_KERNEL);
1005         if (!port_tty)
1006                 return -ENOMEM;
1007
1008         port_vcc = vcc_get(tty->index, true);
1009         if (!port_vcc) {
1010                 pr_err("VCC: install: Failed to find VCC port\n");
1011                 tty->port = NULL;
1012                 kfree(port_tty);
1013                 return -ENODEV;
1014         }
1015
1016         tty_port_init(port_tty);
1017         port_tty->ops = &vcc_port_ops;
1018         tty->port = port_tty;
1019
1020         port_vcc->tty = tty;
1021
1022         vcc_put(port_vcc, true);
1023
1024         return 0;
1025 }
1026
1027 static void vcc_cleanup(struct tty_struct *tty)
1028 {
1029         struct vcc_port *port;
1030
1031         if (unlikely(!tty)) {
1032                 pr_err("VCC: cleanup: Invalid TTY handle\n");
1033                 return;
1034         }
1035
1036         port = vcc_get(tty->index, true);
1037         if (port) {
1038                 port->tty = NULL;
1039
1040                 if (port->removed) {
1041                         vcc_table_remove(tty->index);
1042                         kfree(port->vio.name);
1043                         kfree(port->domain);
1044                         kfree(port);
1045                 } else {
1046                         vcc_put(port, true);
1047                 }
1048         }
1049
1050         tty_port_destroy(tty->port);
1051         kfree(tty->port);
1052         tty->port = NULL;
1053 }
1054
1055 static const struct tty_operations vcc_ops = {
1056         .open                   = vcc_open,
1057         .close                  = vcc_close,
1058         .hangup                 = vcc_hangup,
1059         .write                  = vcc_write,
1060         .write_room             = vcc_write_room,
1061         .chars_in_buffer        = vcc_chars_in_buffer,
1062         .break_ctl              = vcc_break_ctl,
1063         .install                = vcc_install,
1064         .cleanup                = vcc_cleanup,
1065 };
1066
1067 #define VCC_TTY_FLAGS   (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
1068
1069 static int vcc_tty_init(void)
1070 {
1071         int rv;
1072
1073         pr_info("VCC: %s\n", version);
1074
1075         vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
1076         if (IS_ERR(vcc_tty_driver)) {
1077                 pr_err("VCC: TTY driver alloc failed\n");
1078                 return PTR_ERR(vcc_tty_driver);
1079         }
1080
1081         vcc_tty_driver->driver_name = vcc_driver_name;
1082         vcc_tty_driver->name = vcc_device_node;
1083
1084         vcc_tty_driver->minor_start = VCC_MINOR_START;
1085         vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1086         vcc_tty_driver->init_termios = vcc_tty_termios;
1087
1088         tty_set_operations(vcc_tty_driver, &vcc_ops);
1089
1090         rv = tty_register_driver(vcc_tty_driver);
1091         if (rv) {
1092                 pr_err("VCC: TTY driver registration failed\n");
1093                 put_tty_driver(vcc_tty_driver);
1094                 vcc_tty_driver = NULL;
1095                 return rv;
1096         }
1097
1098         vccdbg("VCC: TTY driver registered\n");
1099
1100         return 0;
1101 }
1102
1103 static void vcc_tty_exit(void)
1104 {
1105         tty_unregister_driver(vcc_tty_driver);
1106         put_tty_driver(vcc_tty_driver);
1107         vccdbg("VCC: TTY driver unregistered\n");
1108
1109         vcc_tty_driver = NULL;
1110 }
1111
1112 static int __init vcc_init(void)
1113 {
1114         int rv;
1115
1116         rv = vcc_tty_init();
1117         if (rv) {
1118                 pr_err("VCC: TTY init failed\n");
1119                 return rv;
1120         }
1121
1122         rv = vio_register_driver(&vcc_driver);
1123         if (rv) {
1124                 pr_err("VCC: VIO driver registration failed\n");
1125                 vcc_tty_exit();
1126         } else {
1127                 vccdbg("VCC: VIO driver registered successfully\n");
1128         }
1129
1130         return rv;
1131 }
1132
1133 static void __exit vcc_exit(void)
1134 {
1135         vio_unregister_driver(&vcc_driver);
1136         vccdbg("VCC: VIO driver unregistered\n");
1137         vcc_tty_exit();
1138         vccdbg("VCC: TTY driver unregistered\n");
1139 }
1140
1141 module_init(vcc_init);
1142 module_exit(vcc_exit);