drivers/tty/vcc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* vcc.c: sun4v virtual channel concentrator
   3  *
   4  * Copyright (C) 2017 Oracle. All rights reserved.
   5  */
   6
   7 #include <linux/delay.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/sysfs.h>
  12 #include <linux/tty.h>
  13 #include <linux/tty_flip.h>
  14 #include <linux/termios_internal.h>
  15 #include <asm/vio.h>
  16 #include <asm/ldc.h>
  17
  18 MODULE_DESCRIPTION("Sun LDOM virtual console concentrator driver");
  19 MODULE_LICENSE("GPL");
  20 MODULE_VERSION("1.1");
  21
  22 struct vcc_port {
  23         struct vio_driver_state vio;
  24
  25         spinlock_t lock;
  26         char *domain;
  27         struct tty_struct *tty; /* only populated while dev is open */
  28         unsigned long index;    /* index into the vcc_table */
  29
  30         u64 refcnt;
  31         bool excl_locked;
  32
  33         bool removed;
  34
  35         /* This buffer is required to support the tty write_room interface
  36          * and guarantee that any characters that the driver accepts will
  37          * be eventually sent, either immediately or later.
  38          */
  39         size_t chars_in_buffer;
  40         struct vio_vcc buffer;
  41
  42         struct timer_list rx_timer;
  43         struct timer_list tx_timer;
  44 };
  45
  46 /* Microseconds that thread will delay waiting for a vcc port ref */
  47 #define VCC_REF_DELAY           100
  48
  49 #define VCC_MAX_PORTS           1024
  50 #define VCC_MINOR_START         0       /* must be zero */
  51 #define VCC_BUFF_LEN            VIO_VCC_MTU_SIZE
  52
  53 #define VCC_CTL_BREAK           -1
  54 #define VCC_CTL_HUP             -2
  55
  56 static struct tty_driver *vcc_tty_driver;
  57
  58 static struct vcc_port *vcc_table[VCC_MAX_PORTS];
  59 static DEFINE_SPINLOCK(vcc_table_lock);
  60
  61 static unsigned int vcc_dbg;
  62 static unsigned int vcc_dbg_ldc;
  63 static unsigned int vcc_dbg_vio;
  64
  65 module_param(vcc_dbg, uint, 0664);
  66 module_param(vcc_dbg_ldc, uint, 0664);
  67 module_param(vcc_dbg_vio, uint, 0664);
  68
  69 #define VCC_DBG_DRV     0x1
  70 #define VCC_DBG_LDC     0x2
  71 #define VCC_DBG_PKT     0x4
  72
  73 #define vccdbg(f, a...)                                         \
  74         do {                                                    \
  75                 if (vcc_dbg & VCC_DBG_DRV)                      \
  76                         pr_info(f, ## a);                       \
  77         } while (0)                                             \
  78
  79 #define vccdbgl(l)                                              \
  80         do {                                                    \
  81                 if (vcc_dbg & VCC_DBG_LDC)                      \
  82                         ldc_print(l);                           \
  83         } while (0)                                             \
  84
  85 #define vccdbgp(pkt)                                            \
  86         do {                                                    \
  87                 if (vcc_dbg & VCC_DBG_PKT) {                    \
  88                         int i;                                  \
  89                         for (i = 0; i < pkt.tag.stype; i++)     \
  90                                 pr_info("[%c]", pkt.data[i]);   \
  91                 }                                               \
  92         } while (0)                                             \
  93
  94 /* Note: Be careful when adding flags to this line discipline.  Don't
  95  * add anything that will cause echoing or we'll go into recursive
  96  * loop echoing chars back and forth with the console drivers.
  97  */
  98 static const struct ktermios vcc_tty_termios = {
  99         .c_iflag = IGNBRK | IGNPAR,
 100         .c_oflag = OPOST,
 101         .c_cflag = B38400 | CS8 | CREAD | HUPCL,
 102         .c_cc = INIT_C_CC,
 103         .c_ispeed = 38400,
 104         .c_ospeed = 38400
 105 };
 106
 107 /**
 108  * vcc_table_add() - Add VCC port to the VCC table
 109  * @port: pointer to the VCC port
 110  *
 111  * Return: index of the port in the VCC table on success,
 112  *         -1 on failure
 113  */
 114 static int vcc_table_add(struct vcc_port *port)
 115 {
 116         unsigned long flags;
 117         int i;
 118
 119         spin_lock_irqsave(&vcc_table_lock, flags);
 120         for (i = VCC_MINOR_START; i < VCC_MAX_PORTS; i++) {
 121                 if (!vcc_table[i]) {
 122                         vcc_table[i] = port;
 123                         break;
 124                 }
 125         }
 126         spin_unlock_irqrestore(&vcc_table_lock, flags);
 127
 128         if (i < VCC_MAX_PORTS)
 129                 return i;
 130         else
 131                 return -1;
 132 }
 133
 134 /**
 135  * vcc_table_remove() - Removes a VCC port from the VCC table
 136  * @index: Index into the VCC table
 137  */
 138 static void vcc_table_remove(unsigned long index)
 139 {
 140         unsigned long flags;
 141
 142         if (WARN_ON(index >= VCC_MAX_PORTS))
 143                 return;
 144
 145         spin_lock_irqsave(&vcc_table_lock, flags);
 146         vcc_table[index] = NULL;
 147         spin_unlock_irqrestore(&vcc_table_lock, flags);
 148 }
 149
 150 /**
 151  * vcc_get() - Gets a reference to VCC port
 152  * @index: Index into the VCC table
 153  * @excl: Indicates if an exclusive access is requested
 154  *
 155  * Return: reference to the VCC port, if found
 156  *         NULL, if port not found
 157  */
 158 static struct vcc_port *vcc_get(unsigned long index, bool excl)
 159 {
 160         struct vcc_port *port;
 161         unsigned long flags;
 162
 163 try_again:
 164         spin_lock_irqsave(&vcc_table_lock, flags);
 165
 166         port = vcc_table[index];
 167         if (!port) {
 168                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 169                 return NULL;
 170         }
 171
 172         if (!excl) {
 173                 if (port->excl_locked) {
 174                         spin_unlock_irqrestore(&vcc_table_lock, flags);
 175                         udelay(VCC_REF_DELAY);
 176                         goto try_again;
 177                 }
 178                 port->refcnt++;
 179                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 180                 return port;
 181         }
 182
 183         if (port->refcnt) {
 184                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 185                 /* Threads wanting exclusive access will wait half the time,
 186                  * probably giving them higher priority in the case of
 187                  * multiple waiters.
 188                  */
 189                 udelay(VCC_REF_DELAY/2);
 190                 goto try_again;
 191         }
 192
 193         port->refcnt++;
 194         port->excl_locked = true;
 195         spin_unlock_irqrestore(&vcc_table_lock, flags);
 196
 197         return port;
 198 }
 199
 200 /**
 201  * vcc_put() - Returns a reference to VCC port
 202  * @port: pointer to VCC port
 203  * @excl: Indicates if the returned reference is an exclusive reference
 204  *
 205  * Note: It's the caller's responsibility to ensure the correct value
 206  *       for the excl flag
 207  */
 208 static void vcc_put(struct vcc_port *port, bool excl)
 209 {
 210         unsigned long flags;
 211
 212         if (!port)
 213                 return;
 214
 215         spin_lock_irqsave(&vcc_table_lock, flags);
 216
 217         /* check if caller attempted to put with the wrong flags */
 218         if (WARN_ON((excl && !port->excl_locked) ||
 219                     (!excl && port->excl_locked)))
 220                 goto done;
 221
 222         port->refcnt--;
 223
 224         if (excl)
 225                 port->excl_locked = false;
 226
 227 done:
 228         spin_unlock_irqrestore(&vcc_table_lock, flags);
 229 }
 230
 231 /**
 232  * vcc_get_ne() - Get a non-exclusive reference to VCC port
 233  * @index: Index into the VCC table
 234  *
 235  * Gets a non-exclusive reference to VCC port, if it's not removed
 236  *
 237  * Return: pointer to the VCC port, if found
 238  *         NULL, if port not found
 239  */
 240 static struct vcc_port *vcc_get_ne(unsigned long index)
 241 {
 242         struct vcc_port *port;
 243
 244         port = vcc_get(index, false);
 245
 246         if (port && port->removed) {
 247                 vcc_put(port, false);
 248                 return NULL;
 249         }
 250
 251         return port;
 252 }
 253
 254 static void vcc_kick_rx(struct vcc_port *port)
 255 {
 256         struct vio_driver_state *vio = &port->vio;
 257
 258         assert_spin_locked(&port->lock);
 259
 260         if (!timer_pending(&port->rx_timer) && !port->removed) {
 261                 disable_irq_nosync(vio->vdev->rx_irq);
 262                 port->rx_timer.expires = (jiffies + 1);
 263                 add_timer(&port->rx_timer);
 264         }
 265 }
 266
 267 static void vcc_kick_tx(struct vcc_port *port)
 268 {
 269         assert_spin_locked(&port->lock);
 270
 271         if (!timer_pending(&port->tx_timer) && !port->removed) {
 272                 port->tx_timer.expires = (jiffies + 1);
 273                 add_timer(&port->tx_timer);
 274         }
 275 }
 276
 277 static int vcc_rx_check(struct tty_struct *tty, int size)
 278 {
 279         if (WARN_ON(!tty || !tty->port))
 280                 return 1;
 281
 282         /* tty_buffer_request_room won't sleep because it uses
 283          * GFP_ATOMIC flag to allocate buffer
 284          */
 285         if (test_bit(TTY_THROTTLED, &tty->flags) ||
 286             (tty_buffer_request_room(tty->port, VCC_BUFF_LEN) < VCC_BUFF_LEN))
 287                 return 0;
 288
 289         return 1;
 290 }
 291
 292 static int vcc_rx(struct tty_struct *tty, char *buf, int size)
 293 {
 294         int len = 0;
 295
 296         if (WARN_ON(!tty || !tty->port))
 297                 return len;
 298
 299         len = tty_insert_flip_string(tty->port, buf, size);
 300         if (len)
 301                 tty_flip_buffer_push(tty->port);
 302
 303         return len;
 304 }
 305
 306 static int vcc_ldc_read(struct vcc_port *port)
 307 {
 308         struct vio_driver_state *vio = &port->vio;
 309         struct tty_struct *tty;
 310         struct vio_vcc pkt;
 311         int rv = 0;
 312
 313         tty = port->tty;
 314         if (!tty) {
 315                 rv = ldc_rx_reset(vio->lp);
 316                 vccdbg("VCC: reset rx q: rv=%d\n", rv);
 317                 goto done;
 318         }
 319
 320         /* Read as long as LDC has incoming data. */
 321         while (1) {
 322                 if (!vcc_rx_check(tty, VIO_VCC_MTU_SIZE)) {
 323                         vcc_kick_rx(port);
 324                         break;
 325                 }
 326
 327                 vccdbgl(vio->lp);
 328
 329                 rv = ldc_read(vio->lp, &pkt, sizeof(pkt));
 330                 if (rv <= 0)
 331                         break;
 332
 333                 vccdbg("VCC: ldc_read()=%d\n", rv);
 334                 vccdbg("TAG [%02x:%02x:%04x:%08x]\n",
 335                        pkt.tag.type, pkt.tag.stype,
 336                        pkt.tag.stype_env, pkt.tag.sid);
 337
 338                 if (pkt.tag.type == VIO_TYPE_DATA) {
 339                         vccdbgp(pkt);
 340                         /* vcc_rx_check ensures memory availability */
 341                         vcc_rx(tty, pkt.data, pkt.tag.stype);
 342                 } else {
 343                         pr_err("VCC: unknown msg [%02x:%02x:%04x:%08x]\n",
 344                                pkt.tag.type, pkt.tag.stype,
 345                                pkt.tag.stype_env, pkt.tag.sid);
 346                         rv = -ECONNRESET;
 347                         break;
 348                 }
 349
 350                 WARN_ON(rv != LDC_PACKET_SIZE);
 351         }
 352
 353 done:
 354         return rv;
 355 }
 356
 357 static void vcc_rx_timer(struct timer_list *t)
 358 {
 359         struct vcc_port *port = from_timer(port, t, rx_timer);
 360         struct vio_driver_state *vio;
 361         unsigned long flags;
 362         int rv;
 363
 364         spin_lock_irqsave(&port->lock, flags);
 365         port->rx_timer.expires = 0;
 366
 367         vio = &port->vio;
 368
 369         enable_irq(vio->vdev->rx_irq);
 370
 371         if (!port->tty || port->removed)
 372                 goto done;
 373
 374         rv = vcc_ldc_read(port);
 375         if (rv == -ECONNRESET)
 376                 vio_conn_reset(vio);
 377
 378 done:
 379         spin_unlock_irqrestore(&port->lock, flags);
 380         vcc_put(port, false);
 381 }
 382
 383 static void vcc_tx_timer(struct timer_list *t)
 384 {
 385         struct vcc_port *port = from_timer(port, t, tx_timer);
 386         struct vio_vcc *pkt;
 387         unsigned long flags;
 388         size_t tosend = 0;
 389         int rv;
 390
 391         spin_lock_irqsave(&port->lock, flags);
 392         port->tx_timer.expires = 0;
 393
 394         if (!port->tty || port->removed)
 395                 goto done;
 396
 397         tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
 398         if (!tosend)
 399                 goto done;
 400
 401         pkt = &port->buffer;
 402         pkt->tag.type = VIO_TYPE_DATA;
 403         pkt->tag.stype = tosend;
 404         vccdbgl(port->vio.lp);
 405
 406         rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 407         WARN_ON(!rv);
 408
 409         if (rv < 0) {
 410                 vccdbg("VCC: ldc_write()=%d\n", rv);
 411                 vcc_kick_tx(port);
 412         } else {
 413                 struct tty_struct *tty = port->tty;
 414
 415                 port->chars_in_buffer = 0;
 416                 if (tty)
 417                         tty_wakeup(tty);
 418         }
 419
 420 done:
 421         spin_unlock_irqrestore(&port->lock, flags);
 422         vcc_put(port, false);
 423 }
 424
 425 /**
 426  * vcc_event() - LDC event processing engine
 427  * @arg: VCC private data
 428  * @event: LDC event
 429  *
 430  * Handles LDC events for VCC
 431  */
 432 static void vcc_event(void *arg, int event)
 433 {
 434         struct vio_driver_state *vio;
 435         struct vcc_port *port;
 436         unsigned long flags;
 437         int rv;
 438
 439         port = arg;
 440         vio = &port->vio;
 441
 442         spin_lock_irqsave(&port->lock, flags);
 443
 444         switch (event) {
 445         case LDC_EVENT_RESET:
 446         case LDC_EVENT_UP:
 447                 vio_link_state_change(vio, event);
 448                 break;
 449
 450         case LDC_EVENT_DATA_READY:
 451                 rv = vcc_ldc_read(port);
 452                 if (rv == -ECONNRESET)
 453                         vio_conn_reset(vio);
 454                 break;
 455
 456         default:
 457                 pr_err("VCC: unexpected LDC event(%d)\n", event);
 458         }
 459
 460         spin_unlock_irqrestore(&port->lock, flags);
 461 }
 462
 463 static struct ldc_channel_config vcc_ldc_cfg = {
 464         .event          = vcc_event,
 465         .mtu            = VIO_VCC_MTU_SIZE,
 466         .mode           = LDC_MODE_RAW,
 467         .debug          = 0,
 468 };
 469
 470 /* Ordered from largest major to lowest */
 471 static struct vio_version vcc_versions[] = {
 472         { .major = 1, .minor = 0 },
 473 };
 474
 475 static struct tty_port_operations vcc_port_ops = { 0 };
 476
 477 static ssize_t domain_show(struct device *dev,
 478                            struct device_attribute *attr,
 479                            char *buf)
 480 {
 481         struct vcc_port *port;
 482         int rv;
 483
 484         port = dev_get_drvdata(dev);
 485         if (!port)
 486                 return -ENODEV;
 487
 488         rv = scnprintf(buf, PAGE_SIZE, "%s\n", port->domain);
 489
 490         return rv;
 491 }
 492
 493 static int vcc_send_ctl(struct vcc_port *port, int ctl)
 494 {
 495         struct vio_vcc pkt;
 496         int rv;
 497
 498         pkt.tag.type = VIO_TYPE_CTRL;
 499         pkt.tag.sid = ctl;
 500         pkt.tag.stype = 0;
 501
 502         rv = ldc_write(port->vio.lp, &pkt, sizeof(pkt.tag));
 503         WARN_ON(!rv);
 504         vccdbg("VCC: ldc_write(%ld)=%d\n", sizeof(pkt.tag), rv);
 505
 506         return rv;
 507 }
 508
 509 static ssize_t break_store(struct device *dev,
 510                            struct device_attribute *attr,
 511                            const char *buf, size_t count)
 512 {
 513         struct vcc_port *port;
 514         unsigned long flags;
 515         int rv = count;
 516         int brk;
 517
 518         port = dev_get_drvdata(dev);
 519         if (!port)
 520                 return -ENODEV;
 521
 522         spin_lock_irqsave(&port->lock, flags);
 523
 524         if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
 525                 rv = -EINVAL;
 526         else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 527                 vcc_kick_tx(port);
 528
 529         spin_unlock_irqrestore(&port->lock, flags);
 530
 531         return rv;
 532 }
 533
 534 static DEVICE_ATTR_ADMIN_RO(domain);
 535 static DEVICE_ATTR_WO(break);
 536
 537 static struct attribute *vcc_sysfs_entries[] = {
 538         &dev_attr_domain.attr,
 539         &dev_attr_break.attr,
 540         NULL
 541 };
 542
 543 static struct attribute_group vcc_attribute_group = {
 544         .name = NULL,
 545         .attrs = vcc_sysfs_entries,
 546 };
 547
 548 /**
 549  * vcc_probe() - Initialize VCC port
 550  * @vdev: Pointer to VIO device of the new VCC port
 551  * @id: VIO device ID
 552  *
 553  * Initializes a VCC port to receive serial console data from
 554  * the guest domain. Sets up a TTY end point on the control
 555  * domain. Sets up VIO/LDC link between the guest & control
 556  * domain endpoints.
 557  *
 558  * Return: status of the probe
 559  */
 560 static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 561 {
 562         struct mdesc_handle *hp;
 563         struct vcc_port *port;
 564         struct device *dev;
 565         const char *domain;
 566         char *name;
 567         u64 node;
 568         int rv;
 569
 570         vccdbg("VCC: name=%s\n", dev_name(&vdev->dev));
 571
 572         if (!vcc_tty_driver) {
 573                 pr_err("VCC: TTY driver not registered\n");
 574                 return -ENODEV;
 575         }
 576
 577         port = kzalloc(sizeof(struct vcc_port), GFP_KERNEL);
 578         if (!port)
 579                 return -ENOMEM;
 580
 581         name = kstrdup(dev_name(&vdev->dev), GFP_KERNEL);
 582
 583         rv = vio_driver_init(&port->vio, vdev, VDEV_CONSOLE_CON, vcc_versions,
 584                              ARRAY_SIZE(vcc_versions), NULL, name);
 585         if (rv)
 586                 goto free_port;
 587
 588         port->vio.debug = vcc_dbg_vio;
 589         vcc_ldc_cfg.debug = vcc_dbg_ldc;
 590
 591         rv = vio_ldc_alloc(&port->vio, &vcc_ldc_cfg, port);
 592         if (rv)
 593                 goto free_port;
 594
 595         spin_lock_init(&port->lock);
 596
 597         port->index = vcc_table_add(port);
 598         if (port->index == -1) {
 599                 pr_err("VCC: no more TTY indices left for allocation\n");
 600                 rv = -ENOMEM;
 601                 goto free_ldc;
 602         }
 603
 604         /* Register the device using VCC table index as TTY index */
 605         dev = tty_register_device(vcc_tty_driver, port->index, &vdev->dev);
 606         if (IS_ERR(dev)) {
 607                 rv = PTR_ERR(dev);
 608                 goto free_table;
 609         }
 610
 611         hp = mdesc_grab();
 612
 613         node = vio_vdev_node(hp, vdev);
 614         if (node == MDESC_NODE_NULL) {
 615                 rv = -ENXIO;
 616                 mdesc_release(hp);
 617                 goto unreg_tty;
 618         }
 619
 620         domain = mdesc_get_property(hp, node, "vcc-domain-name", NULL);
 621         if (!domain) {
 622                 rv = -ENXIO;
 623                 mdesc_release(hp);
 624                 goto unreg_tty;
 625         }
 626         port->domain = kstrdup(domain, GFP_KERNEL);
 627
 628         mdesc_release(hp);
 629
 630         rv = sysfs_create_group(&vdev->dev.kobj, &vcc_attribute_group);
 631         if (rv)
 632                 goto free_domain;
 633
 634         timer_setup(&port->rx_timer, vcc_rx_timer, 0);
 635         timer_setup(&port->tx_timer, vcc_tx_timer, 0);
 636
 637         dev_set_drvdata(&vdev->dev, port);
 638
 639         /* It's possible to receive IRQs in the middle of vio_port_up. Disable
 640          * IRQs until the port is up.
 641          */
 642         disable_irq_nosync(vdev->rx_irq);
 643         vio_port_up(&port->vio);
 644         enable_irq(vdev->rx_irq);
 645
 646         return 0;
 647
 648 free_domain:
 649         kfree(port->domain);
 650 unreg_tty:
 651         tty_unregister_device(vcc_tty_driver, port->index);
 652 free_table:
 653         vcc_table_remove(port->index);
 654 free_ldc:
 655         vio_ldc_free(&port->vio);
 656 free_port:
 657         kfree(name);
 658         kfree(port);
 659
 660         return rv;
 661 }
 662
 663 /**
 664  * vcc_remove() - Terminate a VCC port
 665  * @vdev: Pointer to VIO device of the VCC port
 666  *
 667  * Terminates a VCC port. Sets up the teardown of TTY and
 668  * VIO/LDC link between guest and primary domains.
 669  *
 670  * Return: status of removal
 671  */
 672 static void vcc_remove(struct vio_dev *vdev)
 673 {
 674         struct vcc_port *port = dev_get_drvdata(&vdev->dev);
 675
 676         del_timer_sync(&port->rx_timer);
 677         del_timer_sync(&port->tx_timer);
 678
 679         /* If there's a process with the device open, do a synchronous
 680          * hangup of the TTY. This *may* cause the process to call close
 681          * asynchronously, but it's not guaranteed.
 682          */
 683         if (port->tty)
 684                 tty_vhangup(port->tty);
 685
 686         /* Get exclusive reference to VCC, ensures that there are no other
 687          * clients to this port. This cannot fail.
 688          */
 689         vcc_get(port->index, true);
 690
 691         tty_unregister_device(vcc_tty_driver, port->index);
 692
 693         del_timer_sync(&port->vio.timer);
 694         vio_ldc_free(&port->vio);
 695         sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
 696         dev_set_drvdata(&vdev->dev, NULL);
 697         if (port->tty) {
 698                 port->removed = true;
 699                 vcc_put(port, true);
 700         } else {
 701                 vcc_table_remove(port->index);
 702
 703                 kfree(port->vio.name);
 704                 kfree(port->domain);
 705                 kfree(port);
 706         }
 707 }
 708
 709 static const struct vio_device_id vcc_match[] = {
 710         {
 711                 .type = "vcc-port",
 712         },
 713         {},
 714 };
 715 MODULE_DEVICE_TABLE(vio, vcc_match);
 716
 717 static struct vio_driver vcc_driver = {
 718         .id_table       = vcc_match,
 719         .probe          = vcc_probe,
 720         .remove         = vcc_remove,
 721         .name           = "vcc",
 722 };
 723
 724 static int vcc_open(struct tty_struct *tty, struct file *vcc_file)
 725 {
 726         struct vcc_port *port;
 727
 728         if (tty->count > 1)
 729                 return -EBUSY;
 730
 731         port = vcc_get_ne(tty->index);
 732         if (unlikely(!port)) {
 733                 pr_err("VCC: open: Failed to find VCC port\n");
 734                 return -ENODEV;
 735         }
 736
 737         if (unlikely(!port->vio.lp)) {
 738                 pr_err("VCC: open: LDC channel not configured\n");
 739                 vcc_put(port, false);
 740                 return -EPIPE;
 741         }
 742         vccdbgl(port->vio.lp);
 743
 744         vcc_put(port, false);
 745
 746         if (unlikely(!tty->port)) {
 747                 pr_err("VCC: open: TTY port not found\n");
 748                 return -ENXIO;
 749         }
 750
 751         if (unlikely(!tty->port->ops)) {
 752                 pr_err("VCC: open: TTY ops not defined\n");
 753                 return -ENXIO;
 754         }
 755
 756         return tty_port_open(tty->port, tty, vcc_file);
 757 }
 758
 759 static void vcc_close(struct tty_struct *tty, struct file *vcc_file)
 760 {
 761         if (unlikely(tty->count > 1))
 762                 return;
 763
 764         if (unlikely(!tty->port)) {
 765                 pr_err("VCC: close: TTY port not found\n");
 766                 return;
 767         }
 768
 769         tty_port_close(tty->port, tty, vcc_file);
 770 }
 771
 772 static void vcc_ldc_hup(struct vcc_port *port)
 773 {
 774         unsigned long flags;
 775
 776         spin_lock_irqsave(&port->lock, flags);
 777
 778         if (vcc_send_ctl(port, VCC_CTL_HUP) < 0)
 779                 vcc_kick_tx(port);
 780
 781         spin_unlock_irqrestore(&port->lock, flags);
 782 }
 783
 784 static void vcc_hangup(struct tty_struct *tty)
 785 {
 786         struct vcc_port *port;
 787
 788         port = vcc_get_ne(tty->index);
 789         if (unlikely(!port)) {
 790                 pr_err("VCC: hangup: Failed to find VCC port\n");
 791                 return;
 792         }
 793
 794         if (unlikely(!tty->port)) {
 795                 pr_err("VCC: hangup: TTY port not found\n");
 796                 vcc_put(port, false);
 797                 return;
 798         }
 799
 800         vcc_ldc_hup(port);
 801
 802         vcc_put(port, false);
 803
 804         tty_port_hangup(tty->port);
 805 }
 806
 807 static ssize_t vcc_write(struct tty_struct *tty, const u8 *buf, size_t count)
 808 {
 809         struct vcc_port *port;
 810         struct vio_vcc *pkt;
 811         unsigned long flags;
 812         size_t total_sent = 0;
 813         size_t tosend = 0;
 814         int rv = -EINVAL;
 815
 816         port = vcc_get_ne(tty->index);
 817         if (unlikely(!port)) {
 818                 pr_err("VCC: write: Failed to find VCC port");
 819                 return -ENODEV;
 820         }
 821
 822         spin_lock_irqsave(&port->lock, flags);
 823
 824         pkt = &port->buffer;
 825         pkt->tag.type = VIO_TYPE_DATA;
 826
 827         while (count > 0) {
 828                 /* Minimum of data to write and space available */
 829                 tosend = min_t(size_t, count,
 830                                (VCC_BUFF_LEN - port->chars_in_buffer));
 831
 832                 if (!tosend)
 833                         break;
 834
 835                 memcpy(&pkt->data[port->chars_in_buffer], &buf[total_sent],
 836                        tosend);
 837                 port->chars_in_buffer += tosend;
 838                 pkt->tag.stype = tosend;
 839
 840                 vccdbg("TAG [%02x:%02x:%04x:%08x]\n", pkt->tag.type,
 841                        pkt->tag.stype, pkt->tag.stype_env, pkt->tag.sid);
 842                 vccdbg("DATA [%s]\n", pkt->data);
 843                 vccdbgl(port->vio.lp);
 844
 845                 /* Since we know we have enough room in VCC buffer for tosend
 846                  * we record that it was sent regardless of whether the
 847                  * hypervisor actually took it because we have it buffered.
 848                  */
 849                 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 850                 vccdbg("VCC: write: ldc_write(%zu)=%d\n",
 851                        (VIO_TAG_SIZE + tosend), rv);
 852
 853                 total_sent += tosend;
 854                 count -= tosend;
 855                 if (rv < 0) {
 856                         vcc_kick_tx(port);
 857                         break;
 858                 }
 859
 860                 port->chars_in_buffer = 0;
 861         }
 862
 863         spin_unlock_irqrestore(&port->lock, flags);
 864
 865         vcc_put(port, false);
 866
 867         vccdbg("VCC: write: total=%zu rv=%d", total_sent, rv);
 868
 869         return total_sent ? total_sent : rv;
 870 }
 871
 872 static unsigned int vcc_write_room(struct tty_struct *tty)
 873 {
 874         struct vcc_port *port;
 875         unsigned int num;
 876
 877         port = vcc_get_ne(tty->index);
 878         if (unlikely(!port)) {
 879                 pr_err("VCC: write_room: Failed to find VCC port\n");
 880                 return 0;
 881         }
 882
 883         num = VCC_BUFF_LEN - port->chars_in_buffer;
 884
 885         vcc_put(port, false);
 886
 887         return num;
 888 }
 889
 890 static unsigned int vcc_chars_in_buffer(struct tty_struct *tty)
 891 {
 892         struct vcc_port *port;
 893         unsigned int num;
 894
 895         port = vcc_get_ne(tty->index);
 896         if (unlikely(!port)) {
 897                 pr_err("VCC: chars_in_buffer: Failed to find VCC port\n");
 898                 return 0;
 899         }
 900
 901         num = port->chars_in_buffer;
 902
 903         vcc_put(port, false);
 904
 905         return num;
 906 }
 907
 908 static int vcc_break_ctl(struct tty_struct *tty, int state)
 909 {
 910         struct vcc_port *port;
 911         unsigned long flags;
 912
 913         port = vcc_get_ne(tty->index);
 914         if (unlikely(!port)) {
 915                 pr_err("VCC: break_ctl: Failed to find VCC port\n");
 916                 return -ENODEV;
 917         }
 918
 919         /* Turn off break */
 920         if (state == 0) {
 921                 vcc_put(port, false);
 922                 return 0;
 923         }
 924
 925         spin_lock_irqsave(&port->lock, flags);
 926
 927         if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 928                 vcc_kick_tx(port);
 929
 930         spin_unlock_irqrestore(&port->lock, flags);
 931
 932         vcc_put(port, false);
 933
 934         return 0;
 935 }
 936
 937 static int vcc_install(struct tty_driver *driver, struct tty_struct *tty)
 938 {
 939         struct vcc_port *port_vcc;
 940         struct tty_port *port_tty;
 941         int ret;
 942
 943         if (tty->index >= VCC_MAX_PORTS)
 944                 return -EINVAL;
 945
 946         ret = tty_standard_install(driver, tty);
 947         if (ret)
 948                 return ret;
 949
 950         port_tty = kzalloc(sizeof(struct tty_port), GFP_KERNEL);
 951         if (!port_tty)
 952                 return -ENOMEM;
 953
 954         port_vcc = vcc_get(tty->index, true);
 955         if (!port_vcc) {
 956                 pr_err("VCC: install: Failed to find VCC port\n");
 957                 tty->port = NULL;
 958                 kfree(port_tty);
 959                 return -ENODEV;
 960         }
 961
 962         tty_port_init(port_tty);
 963         port_tty->ops = &vcc_port_ops;
 964         tty->port = port_tty;
 965
 966         port_vcc->tty = tty;
 967
 968         vcc_put(port_vcc, true);
 969
 970         return 0;
 971 }
 972
 973 static void vcc_cleanup(struct tty_struct *tty)
 974 {
 975         struct vcc_port *port;
 976
 977         port = vcc_get(tty->index, true);
 978         if (port) {
 979                 port->tty = NULL;
 980
 981                 if (port->removed) {
 982                         vcc_table_remove(tty->index);
 983                         kfree(port->vio.name);
 984                         kfree(port->domain);
 985                         kfree(port);
 986                 } else {
 987                         vcc_put(port, true);
 988                 }
 989         }
 990
 991         tty_port_destroy(tty->port);
 992         kfree(tty->port);
 993         tty->port = NULL;
 994 }
 995
 996 static const struct tty_operations vcc_ops = {
 997         .open                   = vcc_open,
 998         .close                  = vcc_close,
 999         .hangup                 = vcc_hangup,
1000         .write                  = vcc_write,
1001         .write_room             = vcc_write_room,
1002         .chars_in_buffer        = vcc_chars_in_buffer,
1003         .break_ctl              = vcc_break_ctl,
1004         .install                = vcc_install,
1005         .cleanup                = vcc_cleanup,
1006 };
1007
1008 #define VCC_TTY_FLAGS   (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
1009
1010 static int vcc_tty_init(void)
1011 {
1012         int rv;
1013
1014         vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
1015         if (IS_ERR(vcc_tty_driver)) {
1016                 pr_err("VCC: TTY driver alloc failed\n");
1017                 return PTR_ERR(vcc_tty_driver);
1018         }
1019
1020         vcc_tty_driver->driver_name = "vcc";
1021         vcc_tty_driver->name = "vcc";
1022
1023         vcc_tty_driver->minor_start = VCC_MINOR_START;
1024         vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1025         vcc_tty_driver->init_termios = vcc_tty_termios;
1026
1027         tty_set_operations(vcc_tty_driver, &vcc_ops);
1028
1029         rv = tty_register_driver(vcc_tty_driver);
1030         if (rv) {
1031                 pr_err("VCC: TTY driver registration failed\n");
1032                 tty_driver_kref_put(vcc_tty_driver);
1033                 vcc_tty_driver = NULL;
1034                 return rv;
1035         }
1036
1037         vccdbg("VCC: TTY driver registered\n");
1038
1039         return 0;
1040 }
1041
1042 static void vcc_tty_exit(void)
1043 {
1044         tty_unregister_driver(vcc_tty_driver);
1045         tty_driver_kref_put(vcc_tty_driver);
1046         vccdbg("VCC: TTY driver unregistered\n");
1047
1048         vcc_tty_driver = NULL;
1049 }
1050
1051 static int __init vcc_init(void)
1052 {
1053         int rv;
1054
1055         rv = vcc_tty_init();
1056         if (rv) {
1057                 pr_err("VCC: TTY init failed\n");
1058                 return rv;
1059         }
1060
1061         rv = vio_register_driver(&vcc_driver);
1062         if (rv) {
1063                 pr_err("VCC: VIO driver registration failed\n");
1064                 vcc_tty_exit();
1065         } else {
1066                 vccdbg("VCC: VIO driver registered successfully\n");
1067         }
1068
1069         return rv;
1070 }
1071
1072 static void __exit vcc_exit(void)
1073 {
1074         vio_unregister_driver(&vcc_driver);
1075         vccdbg("VCC: VIO driver unregistered\n");
1076         vcc_tty_exit();
1077         vccdbg("VCC: TTY driver unregistered\n");
1078 }
1079
1080 module_init(vcc_init);
1081 module_exit(vcc_exit);