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