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                 rv = -ENOMEM;
 616                 goto free_ldc;
 617         }
 618
 619         /* Register the device using VCC table index as TTY index */
 620         dev = tty_register_device(vcc_tty_driver, port->index, &vdev->dev);
 621         if (IS_ERR(dev)) {
 622                 rv = PTR_ERR(dev);
 623                 goto free_table;
 624         }
 625
 626         hp = mdesc_grab();
 627
 628         node = vio_vdev_node(hp, vdev);
 629         if (node == MDESC_NODE_NULL) {
 630                 rv = -ENXIO;
 631                 mdesc_release(hp);
 632                 goto unreg_tty;
 633         }
 634
 635         domain = mdesc_get_property(hp, node, "vcc-domain-name", NULL);
 636         if (!domain) {
 637                 rv = -ENXIO;
 638                 mdesc_release(hp);
 639                 goto unreg_tty;
 640         }
 641         port->domain = kstrdup(domain, GFP_KERNEL);
 642
 643         mdesc_release(hp);
 644
 645         rv = sysfs_create_group(&vdev->dev.kobj, &vcc_attribute_group);
 646         if (rv)
 647                 goto free_domain;
 648
 649         init_timer(&port->rx_timer);
 650         port->rx_timer.function = vcc_rx_timer;
 651         port->rx_timer.data = port->index;
 652
 653         init_timer(&port->tx_timer);
 654         port->tx_timer.function = vcc_tx_timer;
 655         port->tx_timer.data = port->index;
 656
 657         dev_set_drvdata(&vdev->dev, port);
 658
 659         /* It's possible to receive IRQs in the middle of vio_port_up. Disable
 660          * IRQs until the port is up.
 661          */
 662         disable_irq_nosync(vdev->rx_irq);
 663         vio_port_up(&port->vio);
 664         enable_irq(vdev->rx_irq);
 665
 666         return 0;
 667
 668 free_domain:
 669         kfree(port->domain);
 670 unreg_tty:
 671         tty_unregister_device(vcc_tty_driver, port->index);
 672 free_table:
 673         vcc_table_remove(port->index);
 674 free_ldc:
 675         vio_ldc_free(&port->vio);
 676 free_port:
 677         kfree(name);
 678         kfree(port);
 679
 680         return rv;
 681 }
 682
 683 /**
 684  * vcc_remove() - Terminate a VCC port
 685  * @vdev: Pointer to VIO device of the VCC port
 686  *
 687  * Terminates a VCC port. Sets up the teardown of TTY and
 688  * VIO/LDC link between guest and primary domains.
 689  *
 690  * Return: status of removal
 691  */
 692 static int vcc_remove(struct vio_dev *vdev)
 693 {
 694         struct vcc_port *port = dev_get_drvdata(&vdev->dev);
 695
 696         if (!port)
 697                 return -ENODEV;
 698
 699         del_timer_sync(&port->rx_timer);
 700         del_timer_sync(&port->tx_timer);
 701
 702         /* If there's a process with the device open, do a synchronous
 703          * hangup of the TTY. This *may* cause the process to call close
 704          * asynchronously, but it's not guaranteed.
 705          */
 706         if (port->tty)
 707                 tty_vhangup(port->tty);
 708
 709         /* Get exclusive reference to VCC, ensures that there are no other
 710          * clients to this port
 711          */
 712         port = vcc_get(port->index, true);
 713
 714         if (WARN_ON(!port))
 715                 return -ENODEV;
 716
 717         tty_unregister_device(vcc_tty_driver, port->index);
 718
 719         del_timer_sync(&port->vio.timer);
 720         vio_ldc_free(&port->vio);
 721         sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
 722         dev_set_drvdata(&vdev->dev, NULL);
 723         if (port->tty) {
 724                 port->removed = true;
 725                 vcc_put(port, true);
 726         } else {
 727                 vcc_table_remove(port->index);
 728
 729                 kfree(port->vio.name);
 730                 kfree(port->domain);
 731                 kfree(port);
 732         }
 733
 734         return 0;
 735 }
 736
 737 static const struct vio_device_id vcc_match[] = {
 738         {
 739                 .type = "vcc-port",
 740         },
 741         {},
 742 };
 743 MODULE_DEVICE_TABLE(vio, vcc_match);
 744
 745 static struct vio_driver vcc_driver = {
 746         .id_table       = vcc_match,
 747         .probe          = vcc_probe,
 748         .remove         = vcc_remove,
 749         .name           = "vcc",
 750 };
 751
 752 static int vcc_open(struct tty_struct *tty, struct file *vcc_file)
 753 {
 754         struct vcc_port *port;
 755
 756         if (unlikely(!tty)) {
 757                 pr_err("VCC: open: Invalid TTY handle\n");
 758                 return -ENXIO;
 759         }
 760
 761         if (tty->count > 1)
 762                 return -EBUSY;
 763
 764         port = vcc_get_ne(tty->index);
 765         if (unlikely(!port)) {
 766                 pr_err("VCC: open: Failed to find VCC port\n");
 767                 return -ENODEV;
 768         }
 769
 770         if (unlikely(!port->vio.lp)) {
 771                 pr_err("VCC: open: LDC channel not configured\n");
 772                 vcc_put(port, false);
 773                 return -EPIPE;
 774         }
 775         vccdbgl(port->vio.lp);
 776
 777         vcc_put(port, false);
 778
 779         if (unlikely(!tty->port)) {
 780                 pr_err("VCC: open: TTY port not found\n");
 781                 return -ENXIO;
 782         }
 783
 784         if (unlikely(!tty->port->ops)) {
 785                 pr_err("VCC: open: TTY ops not defined\n");
 786                 return -ENXIO;
 787         }
 788
 789         return tty_port_open(tty->port, tty, vcc_file);
 790 }
 791
 792 static void vcc_close(struct tty_struct *tty, struct file *vcc_file)
 793 {
 794         if (unlikely(!tty)) {
 795                 pr_err("VCC: close: Invalid TTY handle\n");
 796                 return;
 797         }
 798
 799         if (unlikely(tty->count > 1))
 800                 return;
 801
 802         if (unlikely(!tty->port)) {
 803                 pr_err("VCC: close: TTY port not found\n");
 804                 return;
 805         }
 806
 807         tty_port_close(tty->port, tty, vcc_file);
 808 }
 809
 810 static void vcc_ldc_hup(struct vcc_port *port)
 811 {
 812         unsigned long flags;
 813
 814         spin_lock_irqsave(&port->lock, flags);
 815
 816         if (vcc_send_ctl(port, VCC_CTL_HUP) < 0)
 817                 vcc_kick_tx(port);
 818
 819         spin_unlock_irqrestore(&port->lock, flags);
 820 }
 821
 822 static void vcc_hangup(struct tty_struct *tty)
 823 {
 824         struct vcc_port *port;
 825
 826         if (unlikely(!tty)) {
 827                 pr_err("VCC: hangup: Invalid TTY handle\n");
 828                 return;
 829         }
 830
 831         port = vcc_get_ne(tty->index);
 832         if (unlikely(!port)) {
 833                 pr_err("VCC: hangup: Failed to find VCC port\n");
 834                 return;
 835         }
 836
 837         if (unlikely(!tty->port)) {
 838                 pr_err("VCC: hangup: TTY port not found\n");
 839                 vcc_put(port, false);
 840                 return;
 841         }
 842
 843         vcc_ldc_hup(port);
 844
 845         vcc_put(port, false);
 846
 847         tty_port_hangup(tty->port);
 848 }
 849
 850 static int vcc_write(struct tty_struct *tty, const unsigned char *buf,
 851                      int count)
 852 {
 853         struct vcc_port *port;
 854         struct vio_vcc *pkt;
 855         unsigned long flags;
 856         int total_sent = 0;
 857         int tosend = 0;
 858         int rv = -EINVAL;
 859
 860         if (unlikely(!tty)) {
 861                 pr_err("VCC: write: Invalid TTY handle\n");
 862                 return -ENXIO;
 863         }
 864
 865         port = vcc_get_ne(tty->index);
 866         if (unlikely(!port)) {
 867                 pr_err("VCC: write: Failed to find VCC port");
 868                 return -ENODEV;
 869         }
 870
 871         spin_lock_irqsave(&port->lock, flags);
 872
 873         pkt = &port->buffer;
 874         pkt->tag.type = VIO_TYPE_DATA;
 875
 876         while (count > 0) {
 877                 /* Minimum of data to write and space available */
 878                 tosend = min(count, (VCC_BUFF_LEN - port->chars_in_buffer));
 879
 880                 if (!tosend)
 881                         break;
 882
 883                 memcpy(&pkt->data[port->chars_in_buffer], &buf[total_sent],
 884                        tosend);
 885                 port->chars_in_buffer += tosend;
 886                 pkt->tag.stype = tosend;
 887
 888                 vccdbg("TAG [%02x:%02x:%04x:%08x]\n", pkt->tag.type,
 889                        pkt->tag.stype, pkt->tag.stype_env, pkt->tag.sid);
 890                 vccdbg("DATA [%s]\n", pkt->data);
 891                 vccdbgl(port->vio.lp);
 892
 893                 /* Since we know we have enough room in VCC buffer for tosend
 894                  * we record that it was sent regardless of whether the
 895                  * hypervisor actually took it because we have it buffered.
 896                  */
 897                 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 898                 vccdbg("VCC: write: ldc_write(%d)=%d\n",
 899                        (VIO_TAG_SIZE + tosend), rv);
 900
 901                 total_sent += tosend;
 902                 count -= tosend;
 903                 if (rv < 0) {
 904                         vcc_kick_tx(port);
 905                         break;
 906                 }
 907
 908                 port->chars_in_buffer = 0;
 909         }
 910
 911         spin_unlock_irqrestore(&port->lock, flags);
 912
 913         vcc_put(port, false);
 914
 915         vccdbg("VCC: write: total=%d rv=%d", total_sent, rv);
 916
 917         return total_sent ? total_sent : rv;
 918 }
 919
 920 static int vcc_write_room(struct tty_struct *tty)
 921 {
 922         struct vcc_port *port;
 923         u64 num;
 924
 925         if (unlikely(!tty)) {
 926                 pr_err("VCC: write_room: Invalid TTY handle\n");
 927                 return -ENXIO;
 928         }
 929
 930         port = vcc_get_ne(tty->index);
 931         if (unlikely(!port)) {
 932                 pr_err("VCC: write_room: Failed to find VCC port\n");
 933                 return -ENODEV;
 934         }
 935
 936         num = VCC_BUFF_LEN - port->chars_in_buffer;
 937
 938         vcc_put(port, false);
 939
 940         return num;
 941 }
 942
 943 static int vcc_chars_in_buffer(struct tty_struct *tty)
 944 {
 945         struct vcc_port *port;
 946         u64 num;
 947
 948         if (unlikely(!tty)) {
 949                 pr_err("VCC: chars_in_buffer: Invalid TTY handle\n");
 950                 return -ENXIO;
 951         }
 952
 953         port = vcc_get_ne(tty->index);
 954         if (unlikely(!port)) {
 955                 pr_err("VCC: chars_in_buffer: Failed to find VCC port\n");
 956                 return -ENODEV;
 957         }
 958
 959         num = port->chars_in_buffer;
 960
 961         vcc_put(port, false);
 962
 963         return num;
 964 }
 965
 966 static int vcc_break_ctl(struct tty_struct *tty, int state)
 967 {
 968         struct vcc_port *port;
 969         unsigned long flags;
 970
 971         if (unlikely(!tty)) {
 972                 pr_err("VCC: break_ctl: Invalid TTY handle\n");
 973                 return -ENXIO;
 974         }
 975
 976         port = vcc_get_ne(tty->index);
 977         if (unlikely(!port)) {
 978                 pr_err("VCC: break_ctl: Failed to find VCC port\n");
 979                 return -ENODEV;
 980         }
 981
 982         /* Turn off break */
 983         if (state == 0) {
 984                 vcc_put(port, false);
 985                 return 0;
 986         }
 987
 988         spin_lock_irqsave(&port->lock, flags);
 989
 990         if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 991                 vcc_kick_tx(port);
 992
 993         spin_unlock_irqrestore(&port->lock, flags);
 994
 995         vcc_put(port, false);
 996
 997         return 0;
 998 }
 999
1000 static int vcc_install(struct tty_driver *driver, struct tty_struct *tty)
1001 {
1002         struct vcc_port *port_vcc;
1003         struct tty_port *port_tty;
1004         int ret;
1005
1006         if (unlikely(!tty)) {
1007                 pr_err("VCC: install: Invalid TTY handle\n");
1008                 return -ENXIO;
1009         }
1010
1011         if (tty->index >= VCC_MAX_PORTS)
1012                 return -EINVAL;
1013
1014         ret = tty_standard_install(driver, tty);
1015         if (ret)
1016                 return ret;
1017
1018         port_tty = kzalloc(sizeof(struct tty_port), GFP_KERNEL);
1019         if (!port_tty)
1020                 return -ENOMEM;
1021
1022         port_vcc = vcc_get(tty->index, true);
1023         if (!port_vcc) {
1024                 pr_err("VCC: install: Failed to find VCC port\n");
1025                 tty->port = NULL;
1026                 kfree(port_tty);
1027                 return -ENODEV;
1028         }
1029
1030         tty_port_init(port_tty);
1031         port_tty->ops = &vcc_port_ops;
1032         tty->port = port_tty;
1033
1034         port_vcc->tty = tty;
1035
1036         vcc_put(port_vcc, true);
1037
1038         return 0;
1039 }
1040
1041 static void vcc_cleanup(struct tty_struct *tty)
1042 {
1043         struct vcc_port *port;
1044
1045         if (unlikely(!tty)) {
1046                 pr_err("VCC: cleanup: Invalid TTY handle\n");
1047                 return;
1048         }
1049
1050         port = vcc_get(tty->index, true);
1051         if (port) {
1052                 port->tty = NULL;
1053
1054                 if (port->removed) {
1055                         vcc_table_remove(tty->index);
1056                         kfree(port->vio.name);
1057                         kfree(port->domain);
1058                         kfree(port);
1059                 } else {
1060                         vcc_put(port, true);
1061                 }
1062         }
1063
1064         tty_port_destroy(tty->port);
1065         kfree(tty->port);
1066         tty->port = NULL;
1067 }
1068
1069 static const struct tty_operations vcc_ops = {
1070         .open                   = vcc_open,
1071         .close                  = vcc_close,
1072         .hangup                 = vcc_hangup,
1073         .write                  = vcc_write,
1074         .write_room             = vcc_write_room,
1075         .chars_in_buffer        = vcc_chars_in_buffer,
1076         .break_ctl              = vcc_break_ctl,
1077         .install                = vcc_install,
1078         .cleanup                = vcc_cleanup,
1079 };
1080
1081 #define VCC_TTY_FLAGS   (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
1082
1083 static int vcc_tty_init(void)
1084 {
1085         int rv;
1086
1087         pr_info("VCC: %s\n", version);
1088
1089         vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
1090         if (IS_ERR(vcc_tty_driver)) {
1091                 pr_err("VCC: TTY driver alloc failed\n");
1092                 return PTR_ERR(vcc_tty_driver);
1093         }
1094
1095         vcc_tty_driver->driver_name = vcc_driver_name;
1096         vcc_tty_driver->name = vcc_device_node;
1097
1098         vcc_tty_driver->minor_start = VCC_MINOR_START;
1099         vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1100         vcc_tty_driver->init_termios = vcc_tty_termios;
1101
1102         tty_set_operations(vcc_tty_driver, &vcc_ops);
1103
1104         rv = tty_register_driver(vcc_tty_driver);
1105         if (rv) {
1106                 pr_err("VCC: TTY driver registration failed\n");
1107                 put_tty_driver(vcc_tty_driver);
1108                 vcc_tty_driver = NULL;
1109                 return rv;
1110         }
1111
1112         vccdbg("VCC: TTY driver registered\n");
1113
1114         return 0;
1115 }
1116
1117 static void vcc_tty_exit(void)
1118 {
1119         tty_unregister_driver(vcc_tty_driver);
1120         put_tty_driver(vcc_tty_driver);
1121         vccdbg("VCC: TTY driver unregistered\n");
1122
1123         vcc_tty_driver = NULL;
1124 }
1125
1126 static int __init vcc_init(void)
1127 {
1128         int rv;
1129
1130         rv = vcc_tty_init();
1131         if (rv) {
1132                 pr_err("VCC: TTY init failed\n");
1133                 return rv;
1134         }
1135
1136         rv = vio_register_driver(&vcc_driver);
1137         if (rv) {
1138                 pr_err("VCC: VIO driver registration failed\n");
1139                 vcc_tty_exit();
1140         } else {
1141                 vccdbg("VCC: VIO driver registered successfully\n");
1142         }
1143
1144         return rv;
1145 }
1146
1147 static void __exit vcc_exit(void)
1148 {
1149         vio_unregister_driver(&vcc_driver);
1150         vccdbg("VCC: VIO driver unregistered\n");
1151         vcc_tty_exit();
1152         vccdbg("VCC: TTY driver unregistered\n");
1153 }
1154
1155 module_init(vcc_init);
1156 module_exit(vcc_exit);