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(unsigned long index)
 365 {
 366         struct vio_driver_state *vio;
 367         struct vcc_port *port;
 368         unsigned long flags;
 369         int rv;
 370
 371         port = vcc_get_ne(index);
 372         if (!port)
 373                 return;
 374
 375         spin_lock_irqsave(&port->lock, flags);
 376         port->rx_timer.expires = 0;
 377
 378         vio = &port->vio;
 379
 380         enable_irq(vio->vdev->rx_irq);
 381
 382         if (!port->tty || port->removed)
 383                 goto done;
 384
 385         rv = vcc_ldc_read(port);
 386         if (rv == -ECONNRESET)
 387                 vio_conn_reset(vio);
 388
 389 done:
 390         spin_unlock_irqrestore(&port->lock, flags);
 391         vcc_put(port, false);
 392 }
 393
 394 static void vcc_tx_timer(unsigned long index)
 395 {
 396         struct vcc_port *port;
 397         struct vio_vcc *pkt;
 398         unsigned long flags;
 399         int tosend = 0;
 400         int rv;
 401
 402         port = vcc_get_ne(index);
 403         if (!port)
 404                 return;
 405
 406         spin_lock_irqsave(&port->lock, flags);
 407         port->tx_timer.expires = 0;
 408
 409         if (!port->tty || port->removed)
 410                 goto done;
 411
 412         tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
 413         if (!tosend)
 414                 goto done;
 415
 416         pkt = &port->buffer;
 417         pkt->tag.type = VIO_TYPE_DATA;
 418         pkt->tag.stype = tosend;
 419         vccdbgl(port->vio.lp);
 420
 421         rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 422         WARN_ON(!rv);
 423
 424         if (rv < 0) {
 425                 vccdbg("VCC: ldc_write()=%d\n", rv);
 426                 vcc_kick_tx(port);
 427         } else {
 428                 struct tty_struct *tty = port->tty;
 429
 430                 port->chars_in_buffer = 0;
 431                 if (tty)
 432                         tty_wakeup(tty);
 433         }
 434
 435 done:
 436         spin_unlock_irqrestore(&port->lock, flags);
 437         vcc_put(port, false);
 438 }
 439
 440 /**
 441  * vcc_event() - LDC event processing engine
 442  * @arg: VCC private data
 443  * @event: LDC event
 444  *
 445  * Handles LDC events for VCC
 446  */
 447 static void vcc_event(void *arg, int event)
 448 {
 449         struct vio_driver_state *vio;
 450         struct vcc_port *port;
 451         unsigned long flags;
 452         int rv;
 453
 454         port = arg;
 455         vio = &port->vio;
 456
 457         spin_lock_irqsave(&port->lock, flags);
 458
 459         switch (event) {
 460         case LDC_EVENT_RESET:
 461         case LDC_EVENT_UP:
 462                 vio_link_state_change(vio, event);
 463                 break;
 464
 465         case LDC_EVENT_DATA_READY:
 466                 rv = vcc_ldc_read(port);
 467                 if (rv == -ECONNRESET)
 468                         vio_conn_reset(vio);
 469                 break;
 470
 471         default:
 472                 pr_err("VCC: unexpected LDC event(%d)\n", event);
 473         }
 474
 475         spin_unlock_irqrestore(&port->lock, flags);
 476 }
 477
 478 static struct ldc_channel_config vcc_ldc_cfg = {
 479         .event          = vcc_event,
 480         .mtu            = VIO_VCC_MTU_SIZE,
 481         .mode           = LDC_MODE_RAW,
 482         .debug          = 0,
 483 };
 484
 485 /* Ordered from largest major to lowest */
 486 static struct vio_version vcc_versions[] = {
 487         { .major = 1, .minor = 0 },
 488 };
 489
 490 static struct tty_port_operations vcc_port_ops = { 0 };
 491
 492 static ssize_t vcc_sysfs_domain_show(struct device *dev,
 493                                      struct device_attribute *attr,
 494                                      char *buf)
 495 {
 496         struct vcc_port *port;
 497         int rv;
 498
 499         port = dev_get_drvdata(dev);
 500         if (!port)
 501                 return -ENODEV;
 502
 503         rv = scnprintf(buf, PAGE_SIZE, "%s\n", port->domain);
 504
 505         return rv;
 506 }
 507
 508 static int vcc_send_ctl(struct vcc_port *port, int ctl)
 509 {
 510         struct vio_vcc pkt;
 511         int rv;
 512
 513         pkt.tag.type = VIO_TYPE_CTRL;
 514         pkt.tag.sid = ctl;
 515         pkt.tag.stype = 0;
 516
 517         rv = ldc_write(port->vio.lp, &pkt, sizeof(pkt.tag));
 518         WARN_ON(!rv);
 519         vccdbg("VCC: ldc_write(%ld)=%d\n", sizeof(pkt.tag), rv);
 520
 521         return rv;
 522 }
 523
 524 static ssize_t vcc_sysfs_break_store(struct device *dev,
 525                                      struct device_attribute *attr,
 526                                      const char *buf, size_t count)
 527 {
 528         struct vcc_port *port;
 529         unsigned long flags;
 530         int rv = count;
 531         int brk;
 532
 533         port = dev_get_drvdata(dev);
 534         if (!port)
 535                 return -ENODEV;
 536
 537         spin_lock_irqsave(&port->lock, flags);
 538
 539         if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
 540                 rv = -EINVAL;
 541         else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 542                 vcc_kick_tx(port);
 543
 544         spin_unlock_irqrestore(&port->lock, flags);
 545
 546         return rv;
 547 }
 548
 549 static DEVICE_ATTR(domain, 0400, vcc_sysfs_domain_show, NULL);
 550 static DEVICE_ATTR(break, 0200, NULL, vcc_sysfs_break_store);
 551
 552 static struct attribute *vcc_sysfs_entries[] = {
 553         &dev_attr_domain.attr,
 554         &dev_attr_break.attr,
 555         NULL
 556 };
 557
 558 static struct attribute_group vcc_attribute_group = {
 559         .name = NULL,
 560         .attrs = vcc_sysfs_entries,
 561 };
 562
 563 /**
 564  * vcc_probe() - Initialize VCC port
 565  * @vdev: Pointer to VIO device of the new VCC port
 566  * @id: VIO device ID
 567  *
 568  * Initializes a VCC port to receive serial console data from
 569  * the guest domain. Sets up a TTY end point on the control
 570  * domain. Sets up VIO/LDC link between the guest & control
 571  * domain endpoints.
 572  *
 573  * Return: status of the probe
 574  */
 575 static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 576 {
 577         struct mdesc_handle *hp;
 578         struct vcc_port *port;
 579         struct device *dev;
 580         const char *domain;
 581         char *name;
 582         u64 node;
 583         int rv;
 584
 585         vccdbg("VCC: name=%s\n", dev_name(&vdev->dev));
 586
 587         if (!vcc_tty_driver) {
 588                 pr_err("VCC: TTY driver not registered\n");
 589                 return -ENODEV;
 590         }
 591
 592         port = kzalloc(sizeof(struct vcc_port), GFP_KERNEL);
 593         if (!port)
 594                 return -ENOMEM;
 595
 596         name = kstrdup(dev_name(&vdev->dev), GFP_KERNEL);
 597
 598         rv = vio_driver_init(&port->vio, vdev, VDEV_CONSOLE_CON, vcc_versions,
 599                              ARRAY_SIZE(vcc_versions), NULL, name);
 600         if (rv)
 601                 goto free_port;
 602
 603         port->vio.debug = vcc_dbg_vio;
 604         vcc_ldc_cfg.debug = vcc_dbg_ldc;
 605
 606         rv = vio_ldc_alloc(&port->vio, &vcc_ldc_cfg, port);
 607         if (rv)
 608                 goto free_port;
 609
 610         spin_lock_init(&port->lock);
 611
 612         port->index = vcc_table_add(port);
 613         if (port->index == -1) {
 614                 pr_err("VCC: no more TTY indices left for allocation\n");
 615                 goto free_ldc;
 616         }
 617
 618         /* Register the device using VCC table index as TTY index */
 619         dev = tty_register_device(vcc_tty_driver, port->index, &vdev->dev);
 620         if (IS_ERR(dev)) {
 621                 rv = PTR_ERR(dev);
 622                 goto free_table;
 623         }
 624
 625         hp = mdesc_grab();
 626
 627         node = vio_vdev_node(hp, vdev);
 628         if (node == MDESC_NODE_NULL) {
 629                 rv = -ENXIO;
 630                 mdesc_release(hp);
 631                 goto unreg_tty;
 632         }
 633
 634         domain = mdesc_get_property(hp, node, "vcc-domain-name", NULL);
 635         if (!domain) {
 636                 rv = -ENXIO;
 637                 mdesc_release(hp);
 638                 goto unreg_tty;
 639         }
 640         port->domain = kstrdup(domain, GFP_KERNEL);
 641
 642         mdesc_release(hp);
 643
 644         rv = sysfs_create_group(&vdev->dev.kobj, &vcc_attribute_group);
 645         if (rv)
 646                 goto free_domain;
 647
 648         setup_timer(&port->rx_timer, vcc_rx_timer, port->index);
 649         setup_timer(&port->tx_timer, vcc_tx_timer, port->index);
 650
 651         dev_set_drvdata(&vdev->dev, port);
 652
 653         /* It's possible to receive IRQs in the middle of vio_port_up. Disable
 654          * IRQs until the port is up.
 655          */
 656         disable_irq_nosync(vdev->rx_irq);
 657         vio_port_up(&port->vio);
 658         enable_irq(vdev->rx_irq);
 659
 660         return 0;
 661
 662 free_domain:
 663         kfree(port->domain);
 664 unreg_tty:
 665         tty_unregister_device(vcc_tty_driver, port->index);
 666 free_table:
 667         vcc_table_remove(port->index);
 668 free_ldc:
 669         vio_ldc_free(&port->vio);
 670 free_port:
 671         kfree(name);
 672         kfree(port);
 673
 674         return rv;
 675 }
 676
 677 /**
 678  * vcc_remove() - Terminate a VCC port
 679  * @vdev: Pointer to VIO device of the VCC port
 680  *
 681  * Terminates a VCC port. Sets up the teardown of TTY and
 682  * VIO/LDC link between guest and primary domains.
 683  *
 684  * Return: status of removal
 685  */
 686 static int vcc_remove(struct vio_dev *vdev)
 687 {
 688         struct vcc_port *port = dev_get_drvdata(&vdev->dev);
 689
 690         if (!port)
 691                 return -ENODEV;
 692
 693         del_timer_sync(&port->rx_timer);
 694         del_timer_sync(&port->tx_timer);
 695
 696         /* If there's a process with the device open, do a synchronous
 697          * hangup of the TTY. This *may* cause the process to call close
 698          * asynchronously, but it's not guaranteed.
 699          */
 700         if (port->tty)
 701                 tty_vhangup(port->tty);
 702
 703         /* Get exclusive reference to VCC, ensures that there are no other
 704          * clients to this port
 705          */
 706         port = vcc_get(port->index, true);
 707
 708         if (WARN_ON(!port))
 709                 return -ENODEV;
 710
 711         tty_unregister_device(vcc_tty_driver, port->index);
 712
 713         del_timer_sync(&port->vio.timer);
 714         vio_ldc_free(&port->vio);
 715         sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
 716         dev_set_drvdata(&vdev->dev, NULL);
 717         if (port->tty) {
 718                 port->removed = true;
 719                 vcc_put(port, true);
 720         } else {
 721                 vcc_table_remove(port->index);
 722
 723                 kfree(port->vio.name);
 724                 kfree(port->domain);
 725                 kfree(port);
 726         }
 727
 728         return 0;
 729 }
 730
 731 static const struct vio_device_id vcc_match[] = {
 732         {
 733                 .type = "vcc-port",
 734         },
 735         {},
 736 };
 737 MODULE_DEVICE_TABLE(vio, vcc_match);
 738
 739 static struct vio_driver vcc_driver = {
 740         .id_table       = vcc_match,
 741         .probe          = vcc_probe,
 742         .remove         = vcc_remove,
 743         .name           = "vcc",
 744 };
 745
 746 static int vcc_open(struct tty_struct *tty, struct file *vcc_file)
 747 {
 748         struct vcc_port *port;
 749
 750         if (unlikely(!tty)) {
 751                 pr_err("VCC: open: Invalid TTY handle\n");
 752                 return -ENXIO;
 753         }
 754
 755         if (tty->count > 1)
 756                 return -EBUSY;
 757
 758         port = vcc_get_ne(tty->index);
 759         if (unlikely(!port)) {
 760                 pr_err("VCC: open: Failed to find VCC port\n");
 761                 return -ENODEV;
 762         }
 763
 764         if (unlikely(!port->vio.lp)) {
 765                 pr_err("VCC: open: LDC channel not configured\n");
 766                 vcc_put(port, false);
 767                 return -EPIPE;
 768         }
 769         vccdbgl(port->vio.lp);
 770
 771         vcc_put(port, false);
 772
 773         if (unlikely(!tty->port)) {
 774                 pr_err("VCC: open: TTY port not found\n");
 775                 return -ENXIO;
 776         }
 777
 778         if (unlikely(!tty->port->ops)) {
 779                 pr_err("VCC: open: TTY ops not defined\n");
 780                 return -ENXIO;
 781         }
 782
 783         return tty_port_open(tty->port, tty, vcc_file);
 784 }
 785
 786 static void vcc_close(struct tty_struct *tty, struct file *vcc_file)
 787 {
 788         if (unlikely(!tty)) {
 789                 pr_err("VCC: close: Invalid TTY handle\n");
 790                 return;
 791         }
 792
 793         if (unlikely(tty->count > 1))
 794                 return;
 795
 796         if (unlikely(!tty->port)) {
 797                 pr_err("VCC: close: TTY port not found\n");
 798                 return;
 799         }
 800
 801         tty_port_close(tty->port, tty, vcc_file);
 802 }
 803
 804 static void vcc_ldc_hup(struct vcc_port *port)
 805 {
 806         unsigned long flags;
 807
 808         spin_lock_irqsave(&port->lock, flags);
 809
 810         if (vcc_send_ctl(port, VCC_CTL_HUP) < 0)
 811                 vcc_kick_tx(port);
 812
 813         spin_unlock_irqrestore(&port->lock, flags);
 814 }
 815
 816 static void vcc_hangup(struct tty_struct *tty)
 817 {
 818         struct vcc_port *port;
 819
 820         if (unlikely(!tty)) {
 821                 pr_err("VCC: hangup: Invalid TTY handle\n");
 822                 return;
 823         }
 824
 825         port = vcc_get_ne(tty->index);
 826         if (unlikely(!port)) {
 827                 pr_err("VCC: hangup: Failed to find VCC port\n");
 828                 return;
 829         }
 830
 831         if (unlikely(!tty->port)) {
 832                 pr_err("VCC: hangup: TTY port not found\n");
 833                 vcc_put(port, false);
 834                 return;
 835         }
 836
 837         vcc_ldc_hup(port);
 838
 839         vcc_put(port, false);
 840
 841         tty_port_hangup(tty->port);
 842 }
 843
 844 static int vcc_write(struct tty_struct *tty, const unsigned char *buf,
 845                      int count)
 846 {
 847         struct vcc_port *port;
 848         struct vio_vcc *pkt;
 849         unsigned long flags;
 850         int total_sent = 0;
 851         int tosend = 0;
 852         int rv = -EINVAL;
 853
 854         if (unlikely(!tty)) {
 855                 pr_err("VCC: write: Invalid TTY handle\n");
 856                 return -ENXIO;
 857         }
 858
 859         port = vcc_get_ne(tty->index);
 860         if (unlikely(!port)) {
 861                 pr_err("VCC: write: Failed to find VCC port");
 862                 return -ENODEV;
 863         }
 864
 865         spin_lock_irqsave(&port->lock, flags);
 866
 867         pkt = &port->buffer;
 868         pkt->tag.type = VIO_TYPE_DATA;
 869
 870         while (count > 0) {
 871                 /* Minimum of data to write and space available */
 872                 tosend = min(count, (VCC_BUFF_LEN - port->chars_in_buffer));
 873
 874                 if (!tosend)
 875                         break;
 876
 877                 memcpy(&pkt->data[port->chars_in_buffer], &buf[total_sent],
 878                        tosend);
 879                 port->chars_in_buffer += tosend;
 880                 pkt->tag.stype = tosend;
 881
 882                 vccdbg("TAG [%02x:%02x:%04x:%08x]\n", pkt->tag.type,
 883                        pkt->tag.stype, pkt->tag.stype_env, pkt->tag.sid);
 884                 vccdbg("DATA [%s]\n", pkt->data);
 885                 vccdbgl(port->vio.lp);
 886
 887                 /* Since we know we have enough room in VCC buffer for tosend
 888                  * we record that it was sent regardless of whether the
 889                  * hypervisor actually took it because we have it buffered.
 890                  */
 891                 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 892                 vccdbg("VCC: write: ldc_write(%d)=%d\n",
 893                        (VIO_TAG_SIZE + tosend), rv);
 894
 895                 total_sent += tosend;
 896                 count -= tosend;
 897                 if (rv < 0) {
 898                         vcc_kick_tx(port);
 899                         break;
 900                 }
 901
 902                 port->chars_in_buffer = 0;
 903         }
 904
 905         spin_unlock_irqrestore(&port->lock, flags);
 906
 907         vcc_put(port, false);
 908
 909         vccdbg("VCC: write: total=%d rv=%d", total_sent, rv);
 910
 911         return total_sent ? total_sent : rv;
 912 }
 913
 914 static int vcc_write_room(struct tty_struct *tty)
 915 {
 916         struct vcc_port *port;
 917         u64 num;
 918
 919         if (unlikely(!tty)) {
 920                 pr_err("VCC: write_room: Invalid TTY handle\n");
 921                 return -ENXIO;
 922         }
 923
 924         port = vcc_get_ne(tty->index);
 925         if (unlikely(!port)) {
 926                 pr_err("VCC: write_room: Failed to find VCC port\n");
 927                 return -ENODEV;
 928         }
 929
 930         num = VCC_BUFF_LEN - port->chars_in_buffer;
 931
 932         vcc_put(port, false);
 933
 934         return num;
 935 }
 936
 937 static int vcc_chars_in_buffer(struct tty_struct *tty)
 938 {
 939         struct vcc_port *port;
 940         u64 num;
 941
 942         if (unlikely(!tty)) {
 943                 pr_err("VCC: chars_in_buffer: Invalid TTY handle\n");
 944                 return -ENXIO;
 945         }
 946
 947         port = vcc_get_ne(tty->index);
 948         if (unlikely(!port)) {
 949                 pr_err("VCC: chars_in_buffer: Failed to find VCC port\n");
 950                 return -ENODEV;
 951         }
 952
 953         num = port->chars_in_buffer;
 954
 955         vcc_put(port, false);
 956
 957         return num;
 958 }
 959
 960 static int vcc_break_ctl(struct tty_struct *tty, int state)
 961 {
 962         struct vcc_port *port;
 963         unsigned long flags;
 964
 965         if (unlikely(!tty)) {
 966                 pr_err("VCC: break_ctl: Invalid TTY handle\n");
 967                 return -ENXIO;
 968         }
 969
 970         port = vcc_get_ne(tty->index);
 971         if (unlikely(!port)) {
 972                 pr_err("VCC: break_ctl: Failed to find VCC port\n");
 973                 return -ENODEV;
 974         }
 975
 976         /* Turn off break */
 977         if (state == 0) {
 978                 vcc_put(port, false);
 979                 return 0;
 980         }
 981
 982         spin_lock_irqsave(&port->lock, flags);
 983
 984         if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 985                 vcc_kick_tx(port);
 986
 987         spin_unlock_irqrestore(&port->lock, flags);
 988
 989         vcc_put(port, false);
 990
 991         return 0;
 992 }
 993
 994 static int vcc_install(struct tty_driver *driver, struct tty_struct *tty)
 995 {
 996         struct vcc_port *port_vcc;
 997         struct tty_port *port_tty;
 998         int ret;
 999
1000         if (unlikely(!tty)) {
1001                 pr_err("VCC: install: Invalid TTY handle\n");
1002                 return -ENXIO;
1003         }
1004
1005         if (tty->index >= VCC_MAX_PORTS)
1006                 return -EINVAL;
1007
1008         ret = tty_standard_install(driver, tty);
1009         if (ret)
1010                 return ret;
1011
1012         port_tty = kzalloc(sizeof(struct tty_port), GFP_KERNEL);
1013         if (!port_tty)
1014                 return -ENOMEM;
1015
1016         port_vcc = vcc_get(tty->index, true);
1017         if (!port_vcc) {
1018                 pr_err("VCC: install: Failed to find VCC port\n");
1019                 tty->port = NULL;
1020                 kfree(port_tty);
1021                 return -ENODEV;
1022         }
1023
1024         tty_port_init(port_tty);
1025         port_tty->ops = &vcc_port_ops;
1026         tty->port = port_tty;
1027
1028         port_vcc->tty = tty;
1029
1030         vcc_put(port_vcc, true);
1031
1032         return 0;
1033 }
1034
1035 static void vcc_cleanup(struct tty_struct *tty)
1036 {
1037         struct vcc_port *port;
1038
1039         if (unlikely(!tty)) {
1040                 pr_err("VCC: cleanup: Invalid TTY handle\n");
1041                 return;
1042         }
1043
1044         port = vcc_get(tty->index, true);
1045         if (port) {
1046                 port->tty = NULL;
1047
1048                 if (port->removed) {
1049                         vcc_table_remove(tty->index);
1050                         kfree(port->vio.name);
1051                         kfree(port->domain);
1052                         kfree(port);
1053                 } else {
1054                         vcc_put(port, true);
1055                 }
1056         }
1057
1058         tty_port_destroy(tty->port);
1059         kfree(tty->port);
1060         tty->port = NULL;
1061 }
1062
1063 static const struct tty_operations vcc_ops = {
1064         .open                   = vcc_open,
1065         .close                  = vcc_close,
1066         .hangup                 = vcc_hangup,
1067         .write                  = vcc_write,
1068         .write_room             = vcc_write_room,
1069         .chars_in_buffer        = vcc_chars_in_buffer,
1070         .break_ctl              = vcc_break_ctl,
1071         .install                = vcc_install,
1072         .cleanup                = vcc_cleanup,
1073 };
1074
1075 #define VCC_TTY_FLAGS   (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
1076
1077 static int vcc_tty_init(void)
1078 {
1079         int rv;
1080
1081         pr_info("VCC: %s\n", version);
1082
1083         vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
1084         if (IS_ERR(vcc_tty_driver)) {
1085                 pr_err("VCC: TTY driver alloc failed\n");
1086                 return PTR_ERR(vcc_tty_driver);
1087         }
1088
1089         vcc_tty_driver->driver_name = vcc_driver_name;
1090         vcc_tty_driver->name = vcc_device_node;
1091
1092         vcc_tty_driver->minor_start = VCC_MINOR_START;
1093         vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1094         vcc_tty_driver->init_termios = vcc_tty_termios;
1095
1096         tty_set_operations(vcc_tty_driver, &vcc_ops);
1097
1098         rv = tty_register_driver(vcc_tty_driver);
1099         if (rv) {
1100                 pr_err("VCC: TTY driver registration failed\n");
1101                 put_tty_driver(vcc_tty_driver);
1102                 vcc_tty_driver = NULL;
1103                 return rv;
1104         }
1105
1106         vccdbg("VCC: TTY driver registered\n");
1107
1108         return 0;
1109 }
1110
1111 static void vcc_tty_exit(void)
1112 {
1113         tty_unregister_driver(vcc_tty_driver);
1114         put_tty_driver(vcc_tty_driver);
1115         vccdbg("VCC: TTY driver unregistered\n");
1116
1117         vcc_tty_driver = NULL;
1118 }
1119
1120 static int __init vcc_init(void)
1121 {
1122         int rv;
1123
1124         rv = vcc_tty_init();
1125         if (rv) {
1126                 pr_err("VCC: TTY init failed\n");
1127                 return rv;
1128         }
1129
1130         rv = vio_register_driver(&vcc_driver);
1131         if (rv) {
1132                 pr_err("VCC: VIO driver registration failed\n");
1133                 vcc_tty_exit();
1134         } else {
1135                 vccdbg("VCC: VIO driver registered successfully\n");
1136         }
1137
1138         return rv;
1139 }
1140
1141 static void __exit vcc_exit(void)
1142 {
1143         vio_unregister_driver(&vcc_driver);
1144         vccdbg("VCC: VIO driver unregistered\n");
1145         vcc_tty_exit();
1146         vccdbg("VCC: TTY driver unregistered\n");
1147 }
1148
1149 module_init(vcc_init);
1150 module_exit(vcc_exit);