drivers/tty/vcc.c

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This source file includes following definitions.
vcc_table_add
vcc_table_remove
vcc_get
vcc_put
vcc_get_ne
vcc_kick_rx
vcc_kick_tx
vcc_rx_check
vcc_rx
vcc_ldc_read
vcc_rx_timer
vcc_tx_timer
vcc_event
vcc_sysfs_domain_show
vcc_send_ctl
vcc_sysfs_break_store
vcc_probe
vcc_remove
vcc_open
vcc_close
vcc_ldc_hup
vcc_hangup
vcc_write
vcc_write_room
vcc_chars_in_buffer
vcc_break_ctl
vcc_install
vcc_cleanup
vcc_tty_init
vcc_tty_exit
vcc_init
vcc_exit
   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 <asm/vio.h>
  15 #include <asm/ldc.h>
  16 
  17 #define DRV_MODULE_NAME         "vcc"
  18 #define DRV_MODULE_VERSION      "1.1"
  19 #define DRV_MODULE_RELDATE      "July 1, 2017"
  20 
  21 static char version[] =
  22         DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")";
  23 
  24 MODULE_DESCRIPTION("Sun LDOM virtual console concentrator driver");
  25 MODULE_LICENSE("GPL");
  26 MODULE_VERSION(DRV_MODULE_VERSION);
  27 
  28 struct vcc_port {
  29         struct vio_driver_state vio;
  30 
  31         spinlock_t lock;
  32         char *domain;
  33         struct tty_struct *tty; /* only populated while dev is open */
  34         unsigned long index;    /* index into the vcc_table */
  35 
  36         u64 refcnt;
  37         bool excl_locked;
  38 
  39         bool removed;
  40 
  41         /* This buffer is required to support the tty write_room interface
  42          * and guarantee that any characters that the driver accepts will
  43          * be eventually sent, either immediately or later.
  44          */
  45         int chars_in_buffer;
  46         struct vio_vcc buffer;
  47 
  48         struct timer_list rx_timer;
  49         struct timer_list tx_timer;
  50 };
  51 
  52 /* Microseconds that thread will delay waiting for a vcc port ref */
  53 #define VCC_REF_DELAY           100
  54 
  55 #define VCC_MAX_PORTS           1024
  56 #define VCC_MINOR_START         0       /* must be zero */
  57 #define VCC_BUFF_LEN            VIO_VCC_MTU_SIZE
  58 
  59 #define VCC_CTL_BREAK           -1
  60 #define VCC_CTL_HUP             -2
  61 
  62 static const char vcc_driver_name[] = "vcc";
  63 static const char vcc_device_node[] = "vcc";
  64 static struct tty_driver *vcc_tty_driver;
  65 
  66 static struct vcc_port *vcc_table[VCC_MAX_PORTS];
  67 static DEFINE_SPINLOCK(vcc_table_lock);
  68 
  69 int vcc_dbg;
  70 int vcc_dbg_ldc;
  71 int vcc_dbg_vio;
  72 
  73 module_param(vcc_dbg, uint, 0664);
  74 module_param(vcc_dbg_ldc, uint, 0664);
  75 module_param(vcc_dbg_vio, uint, 0664);
  76 
  77 #define VCC_DBG_DRV     0x1
  78 #define VCC_DBG_LDC     0x2
  79 #define VCC_DBG_PKT     0x4
  80 
  81 #define vccdbg(f, a...)                                         \
  82         do {                                                    \
  83                 if (vcc_dbg & VCC_DBG_DRV)                      \
  84                         pr_info(f, ## a);                       \
  85         } while (0)                                             \
  86 
  87 #define vccdbgl(l)                                              \
  88         do {                                                    \
  89                 if (vcc_dbg & VCC_DBG_LDC)                      \
  90                         ldc_print(l);                           \
  91         } while (0)                                             \
  92 
  93 #define vccdbgp(pkt)                                            \
  94         do {                                                    \
  95                 if (vcc_dbg & VCC_DBG_PKT) {                    \
  96                         int i;                                  \
  97                         for (i = 0; i < pkt.tag.stype; i++)     \
  98                                 pr_info("[%c]", pkt.data[i]);   \
  99                 }                                               \
 100         } while (0)                                             \
 101 
 102 /* Note: Be careful when adding flags to this line discipline.  Don't
 103  * add anything that will cause echoing or we'll go into recursive
 104  * loop echoing chars back and forth with the console drivers.
 105  */
 106 static const struct ktermios vcc_tty_termios = {
 107         .c_iflag = IGNBRK | IGNPAR,
 108         .c_oflag = OPOST,
 109         .c_cflag = B38400 | CS8 | CREAD | HUPCL,
 110         .c_cc = INIT_C_CC,
 111         .c_ispeed = 38400,
 112         .c_ospeed = 38400
 113 };
 114 
 115 /**
 116  * vcc_table_add() - Add VCC port to the VCC table
 117  * @port: pointer to the VCC port
 118  *
 119  * Return: index of the port in the VCC table on success,
 120  *         -1 on failure
 121  */
 122 static int vcc_table_add(struct vcc_port *port)
 123 {
 124         unsigned long flags;
 125         int i;
 126 
 127         spin_lock_irqsave(&vcc_table_lock, flags);
 128         for (i = VCC_MINOR_START; i < VCC_MAX_PORTS; i++) {
 129                 if (!vcc_table[i]) {
 130                         vcc_table[i] = port;
 131                         break;
 132                 }
 133         }
 134         spin_unlock_irqrestore(&vcc_table_lock, flags);
 135 
 136         if (i < VCC_MAX_PORTS)
 137                 return i;
 138         else
 139                 return -1;
 140 }
 141 
 142 /**
 143  * vcc_table_remove() - Removes a VCC port from the VCC table
 144  * @index: Index into the VCC table
 145  */
 146 static void vcc_table_remove(unsigned long index)
 147 {
 148         unsigned long flags;
 149 
 150         if (WARN_ON(index >= VCC_MAX_PORTS))
 151                 return;
 152 
 153         spin_lock_irqsave(&vcc_table_lock, flags);
 154         vcc_table[index] = NULL;
 155         spin_unlock_irqrestore(&vcc_table_lock, flags);
 156 }
 157 
 158 /**
 159  * vcc_get() - Gets a reference to VCC port
 160  * @index: Index into the VCC table
 161  * @excl: Indicates if an exclusive access is requested
 162  *
 163  * Return: reference to the VCC port, if found
 164  *         NULL, if port not found
 165  */
 166 static struct vcc_port *vcc_get(unsigned long index, bool excl)
 167 {
 168         struct vcc_port *port;
 169         unsigned long flags;
 170 
 171 try_again:
 172         spin_lock_irqsave(&vcc_table_lock, flags);
 173 
 174         port = vcc_table[index];
 175         if (!port) {
 176                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 177                 return NULL;
 178         }
 179 
 180         if (!excl) {
 181                 if (port->excl_locked) {
 182                         spin_unlock_irqrestore(&vcc_table_lock, flags);
 183                         udelay(VCC_REF_DELAY);
 184                         goto try_again;
 185                 }
 186                 port->refcnt++;
 187                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 188                 return port;
 189         }
 190 
 191         if (port->refcnt) {
 192                 spin_unlock_irqrestore(&vcc_table_lock, flags);
 193                 /* Threads wanting exclusive access will wait half the time,
 194                  * probably giving them higher priority in the case of
 195                  * multiple waiters.
 196                  */
 197                 udelay(VCC_REF_DELAY/2);
 198                 goto try_again;
 199         }
 200 
 201         port->refcnt++;
 202         port->excl_locked = true;
 203         spin_unlock_irqrestore(&vcc_table_lock, flags);
 204 
 205         return port;
 206 }
 207 
 208 /**
 209  * vcc_put() - Returns a reference to VCC port
 210  * @port: pointer to VCC port
 211  * @excl: Indicates if the returned reference is an exclusive reference
 212  *
 213  * Note: It's the caller's responsibility to ensure the correct value
 214  *       for the excl flag
 215  */
 216 static void vcc_put(struct vcc_port *port, bool excl)
 217 {
 218         unsigned long flags;
 219 
 220         if (!port)
 221                 return;
 222 
 223         spin_lock_irqsave(&vcc_table_lock, flags);
 224 
 225         /* check if caller attempted to put with the wrong flags */
 226         if (WARN_ON((excl && !port->excl_locked) ||
 227                     (!excl && port->excl_locked)))
 228                 goto done;
 229 
 230         port->refcnt--;
 231 
 232         if (excl)
 233                 port->excl_locked = false;
 234 
 235 done:
 236         spin_unlock_irqrestore(&vcc_table_lock, flags);
 237 }
 238 
 239 /**
 240  * vcc_get_ne() - Get a non-exclusive reference to VCC port
 241  * @index: Index into the VCC table
 242  *
 243  * Gets a non-exclusive reference to VCC port, if it's not removed
 244  *
 245  * Return: pointer to the VCC port, if found
 246  *         NULL, if port not found
 247  */
 248 static struct vcc_port *vcc_get_ne(unsigned long index)
 249 {
 250         struct vcc_port *port;
 251 
 252         port = vcc_get(index, false);
 253 
 254         if (port && port->removed) {
 255                 vcc_put(port, false);
 256                 return NULL;
 257         }
 258 
 259         return port;
 260 }
 261 
 262 static void vcc_kick_rx(struct vcc_port *port)
 263 {
 264         struct vio_driver_state *vio = &port->vio;
 265 
 266         assert_spin_locked(&port->lock);
 267 
 268         if (!timer_pending(&port->rx_timer) && !port->removed) {
 269                 disable_irq_nosync(vio->vdev->rx_irq);
 270                 port->rx_timer.expires = (jiffies + 1);
 271                 add_timer(&port->rx_timer);
 272         }
 273 }
 274 
 275 static void vcc_kick_tx(struct vcc_port *port)
 276 {
 277         assert_spin_locked(&port->lock);
 278 
 279         if (!timer_pending(&port->tx_timer) && !port->removed) {
 280                 port->tx_timer.expires = (jiffies + 1);
 281                 add_timer(&port->tx_timer);
 282         }
 283 }
 284 
 285 static int vcc_rx_check(struct tty_struct *tty, int size)
 286 {
 287         if (WARN_ON(!tty || !tty->port))
 288                 return 1;
 289 
 290         /* tty_buffer_request_room won't sleep because it uses
 291          * GFP_ATOMIC flag to allocate buffer
 292          */
 293         if (test_bit(TTY_THROTTLED, &tty->flags) ||
 294             (tty_buffer_request_room(tty->port, VCC_BUFF_LEN) < VCC_BUFF_LEN))
 295                 return 0;
 296 
 297         return 1;
 298 }
 299 
 300 static int vcc_rx(struct tty_struct *tty, char *buf, int size)
 301 {
 302         int len = 0;
 303 
 304         if (WARN_ON(!tty || !tty->port))
 305                 return len;
 306 
 307         len = tty_insert_flip_string(tty->port, buf, size);
 308         if (len)
 309                 tty_flip_buffer_push(tty->port);
 310 
 311         return len;
 312 }
 313 
 314 static int vcc_ldc_read(struct vcc_port *port)
 315 {
 316         struct vio_driver_state *vio = &port->vio;
 317         struct tty_struct *tty;
 318         struct vio_vcc pkt;
 319         int rv = 0;
 320 
 321         tty = port->tty;
 322         if (!tty) {
 323                 rv = ldc_rx_reset(vio->lp);
 324                 vccdbg("VCC: reset rx q: rv=%d\n", rv);
 325                 goto done;
 326         }
 327 
 328         /* Read as long as LDC has incoming data. */
 329         while (1) {
 330                 if (!vcc_rx_check(tty, VIO_VCC_MTU_SIZE)) {
 331                         vcc_kick_rx(port);
 332                         break;
 333                 }
 334 
 335                 vccdbgl(vio->lp);
 336 
 337                 rv = ldc_read(vio->lp, &pkt, sizeof(pkt));
 338                 if (rv <= 0)
 339                         break;
 340 
 341                 vccdbg("VCC: ldc_read()=%d\n", rv);
 342                 vccdbg("TAG [%02x:%02x:%04x:%08x]\n",
 343                        pkt.tag.type, pkt.tag.stype,
 344                        pkt.tag.stype_env, pkt.tag.sid);
 345 
 346                 if (pkt.tag.type == VIO_TYPE_DATA) {
 347                         vccdbgp(pkt);
 348                         /* vcc_rx_check ensures memory availability */
 349                         vcc_rx(tty, pkt.data, pkt.tag.stype);
 350                 } else {
 351                         pr_err("VCC: unknown msg [%02x:%02x:%04x:%08x]\n",
 352                                pkt.tag.type, pkt.tag.stype,
 353                                pkt.tag.stype_env, pkt.tag.sid);
 354                         rv = -ECONNRESET;
 355                         break;
 356                 }
 357 
 358                 WARN_ON(rv != LDC_PACKET_SIZE);
 359         }
 360 
 361 done:
 362         return rv;
 363 }
 364 
 365 static void vcc_rx_timer(struct timer_list *t)
 366 {
 367         struct vcc_port *port = from_timer(port, t, rx_timer);
 368         struct vio_driver_state *vio;
 369         unsigned long flags;
 370         int rv;
 371 
 372         spin_lock_irqsave(&port->lock, flags);
 373         port->rx_timer.expires = 0;
 374 
 375         vio = &port->vio;
 376 
 377         enable_irq(vio->vdev->rx_irq);
 378 
 379         if (!port->tty || port->removed)
 380                 goto done;
 381 
 382         rv = vcc_ldc_read(port);
 383         if (rv == -ECONNRESET)
 384                 vio_conn_reset(vio);
 385 
 386 done:
 387         spin_unlock_irqrestore(&port->lock, flags);
 388         vcc_put(port, false);
 389 }
 390 
 391 static void vcc_tx_timer(struct timer_list *t)
 392 {
 393         struct vcc_port *port = from_timer(port, t, tx_timer);
 394         struct vio_vcc *pkt;
 395         unsigned long flags;
 396         int tosend = 0;
 397         int rv;
 398 
 399         spin_lock_irqsave(&port->lock, flags);
 400         port->tx_timer.expires = 0;
 401 
 402         if (!port->tty || port->removed)
 403                 goto done;
 404 
 405         tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
 406         if (!tosend)
 407                 goto done;
 408 
 409         pkt = &port->buffer;
 410         pkt->tag.type = VIO_TYPE_DATA;
 411         pkt->tag.stype = tosend;
 412         vccdbgl(port->vio.lp);
 413 
 414         rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 415         WARN_ON(!rv);
 416 
 417         if (rv < 0) {
 418                 vccdbg("VCC: ldc_write()=%d\n", rv);
 419                 vcc_kick_tx(port);
 420         } else {
 421                 struct tty_struct *tty = port->tty;
 422 
 423                 port->chars_in_buffer = 0;
 424                 if (tty)
 425                         tty_wakeup(tty);
 426         }
 427 
 428 done:
 429         spin_unlock_irqrestore(&port->lock, flags);
 430         vcc_put(port, false);
 431 }
 432 
 433 /**
 434  * vcc_event() - LDC event processing engine
 435  * @arg: VCC private data
 436  * @event: LDC event
 437  *
 438  * Handles LDC events for VCC
 439  */
 440 static void vcc_event(void *arg, int event)
 441 {
 442         struct vio_driver_state *vio;
 443         struct vcc_port *port;
 444         unsigned long flags;
 445         int rv;
 446 
 447         port = arg;
 448         vio = &port->vio;
 449 
 450         spin_lock_irqsave(&port->lock, flags);
 451 
 452         switch (event) {
 453         case LDC_EVENT_RESET:
 454         case LDC_EVENT_UP:
 455                 vio_link_state_change(vio, event);
 456                 break;
 457 
 458         case LDC_EVENT_DATA_READY:
 459                 rv = vcc_ldc_read(port);
 460                 if (rv == -ECONNRESET)
 461                         vio_conn_reset(vio);
 462                 break;
 463 
 464         default:
 465                 pr_err("VCC: unexpected LDC event(%d)\n", event);
 466         }
 467 
 468         spin_unlock_irqrestore(&port->lock, flags);
 469 }
 470 
 471 static struct ldc_channel_config vcc_ldc_cfg = {
 472         .event          = vcc_event,
 473         .mtu            = VIO_VCC_MTU_SIZE,
 474         .mode           = LDC_MODE_RAW,
 475         .debug          = 0,
 476 };
 477 
 478 /* Ordered from largest major to lowest */
 479 static struct vio_version vcc_versions[] = {
 480         { .major = 1, .minor = 0 },
 481 };
 482 
 483 static struct tty_port_operations vcc_port_ops = { 0 };
 484 
 485 static ssize_t vcc_sysfs_domain_show(struct device *dev,
 486                                      struct device_attribute *attr,
 487                                      char *buf)
 488 {
 489         struct vcc_port *port;
 490         int rv;
 491 
 492         port = dev_get_drvdata(dev);
 493         if (!port)
 494                 return -ENODEV;
 495 
 496         rv = scnprintf(buf, PAGE_SIZE, "%s\n", port->domain);
 497 
 498         return rv;
 499 }
 500 
 501 static int vcc_send_ctl(struct vcc_port *port, int ctl)
 502 {
 503         struct vio_vcc pkt;
 504         int rv;
 505 
 506         pkt.tag.type = VIO_TYPE_CTRL;
 507         pkt.tag.sid = ctl;
 508         pkt.tag.stype = 0;
 509 
 510         rv = ldc_write(port->vio.lp, &pkt, sizeof(pkt.tag));
 511         WARN_ON(!rv);
 512         vccdbg("VCC: ldc_write(%ld)=%d\n", sizeof(pkt.tag), rv);
 513 
 514         return rv;
 515 }
 516 
 517 static ssize_t vcc_sysfs_break_store(struct device *dev,
 518                                      struct device_attribute *attr,
 519                                      const char *buf, size_t count)
 520 {
 521         struct vcc_port *port;
 522         unsigned long flags;
 523         int rv = count;
 524         int brk;
 525 
 526         port = dev_get_drvdata(dev);
 527         if (!port)
 528                 return -ENODEV;
 529 
 530         spin_lock_irqsave(&port->lock, flags);
 531 
 532         if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
 533                 rv = -EINVAL;
 534         else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 535                 vcc_kick_tx(port);
 536 
 537         spin_unlock_irqrestore(&port->lock, flags);
 538 
 539         return rv;
 540 }
 541 
 542 static DEVICE_ATTR(domain, 0400, vcc_sysfs_domain_show, NULL);
 543 static DEVICE_ATTR(break, 0200, NULL, vcc_sysfs_break_store);
 544 
 545 static struct attribute *vcc_sysfs_entries[] = {
 546         &dev_attr_domain.attr,
 547         &dev_attr_break.attr,
 548         NULL
 549 };
 550 
 551 static struct attribute_group vcc_attribute_group = {
 552         .name = NULL,
 553         .attrs = vcc_sysfs_entries,
 554 };
 555 
 556 /**
 557  * vcc_probe() - Initialize VCC port
 558  * @vdev: Pointer to VIO device of the new VCC port
 559  * @id: VIO device ID
 560  *
 561  * Initializes a VCC port to receive serial console data from
 562  * the guest domain. Sets up a TTY end point on the control
 563  * domain. Sets up VIO/LDC link between the guest & control
 564  * domain endpoints.
 565  *
 566  * Return: status of the probe
 567  */
 568 static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 569 {
 570         struct mdesc_handle *hp;
 571         struct vcc_port *port;
 572         struct device *dev;
 573         const char *domain;
 574         char *name;
 575         u64 node;
 576         int rv;
 577 
 578         vccdbg("VCC: name=%s\n", dev_name(&vdev->dev));
 579 
 580         if (!vcc_tty_driver) {
 581                 pr_err("VCC: TTY driver not registered\n");
 582                 return -ENODEV;
 583         }
 584 
 585         port = kzalloc(sizeof(struct vcc_port), GFP_KERNEL);
 586         if (!port)
 587                 return -ENOMEM;
 588 
 589         name = kstrdup(dev_name(&vdev->dev), GFP_KERNEL);
 590 
 591         rv = vio_driver_init(&port->vio, vdev, VDEV_CONSOLE_CON, vcc_versions,
 592                              ARRAY_SIZE(vcc_versions), NULL, name);
 593         if (rv)
 594                 goto free_port;
 595 
 596         port->vio.debug = vcc_dbg_vio;
 597         vcc_ldc_cfg.debug = vcc_dbg_ldc;
 598 
 599         rv = vio_ldc_alloc(&port->vio, &vcc_ldc_cfg, port);
 600         if (rv)
 601                 goto free_port;
 602 
 603         spin_lock_init(&port->lock);
 604 
 605         port->index = vcc_table_add(port);
 606         if (port->index == -1) {
 607                 pr_err("VCC: no more TTY indices left for allocation\n");
 608                 goto free_ldc;
 609         }
 610 
 611         /* Register the device using VCC table index as TTY index */
 612         dev = tty_register_device(vcc_tty_driver, port->index, &vdev->dev);
 613         if (IS_ERR(dev)) {
 614                 rv = PTR_ERR(dev);
 615                 goto free_table;
 616         }
 617 
 618         hp = mdesc_grab();
 619 
 620         node = vio_vdev_node(hp, vdev);
 621         if (node == MDESC_NODE_NULL) {
 622                 rv = -ENXIO;
 623                 mdesc_release(hp);
 624                 goto unreg_tty;
 625         }
 626 
 627         domain = mdesc_get_property(hp, node, "vcc-domain-name", NULL);
 628         if (!domain) {
 629                 rv = -ENXIO;
 630                 mdesc_release(hp);
 631                 goto unreg_tty;
 632         }
 633         port->domain = kstrdup(domain, GFP_KERNEL);
 634 
 635         mdesc_release(hp);
 636 
 637         rv = sysfs_create_group(&vdev->dev.kobj, &vcc_attribute_group);
 638         if (rv)
 639                 goto free_domain;
 640 
 641         timer_setup(&port->rx_timer, vcc_rx_timer, 0);
 642         timer_setup(&port->tx_timer, vcc_tx_timer, 0);
 643 
 644         dev_set_drvdata(&vdev->dev, port);
 645 
 646         /* It's possible to receive IRQs in the middle of vio_port_up. Disable
 647          * IRQs until the port is up.
 648          */
 649         disable_irq_nosync(vdev->rx_irq);
 650         vio_port_up(&port->vio);
 651         enable_irq(vdev->rx_irq);
 652 
 653         return 0;
 654 
 655 free_domain:
 656         kfree(port->domain);
 657 unreg_tty:
 658         tty_unregister_device(vcc_tty_driver, port->index);
 659 free_table:
 660         vcc_table_remove(port->index);
 661 free_ldc:
 662         vio_ldc_free(&port->vio);
 663 free_port:
 664         kfree(name);
 665         kfree(port);
 666 
 667         return rv;
 668 }
 669 
 670 /**
 671  * vcc_remove() - Terminate a VCC port
 672  * @vdev: Pointer to VIO device of the VCC port
 673  *
 674  * Terminates a VCC port. Sets up the teardown of TTY and
 675  * VIO/LDC link between guest and primary domains.
 676  *
 677  * Return: status of removal
 678  */
 679 static int vcc_remove(struct vio_dev *vdev)
 680 {
 681         struct vcc_port *port = dev_get_drvdata(&vdev->dev);
 682 
 683         if (!port)
 684                 return -ENODEV;
 685 
 686         del_timer_sync(&port->rx_timer);
 687         del_timer_sync(&port->tx_timer);
 688 
 689         /* If there's a process with the device open, do a synchronous
 690          * hangup of the TTY. This *may* cause the process to call close
 691          * asynchronously, but it's not guaranteed.
 692          */
 693         if (port->tty)
 694                 tty_vhangup(port->tty);
 695 
 696         /* Get exclusive reference to VCC, ensures that there are no other
 697          * clients to this port
 698          */
 699         port = vcc_get(port->index, true);
 700 
 701         if (WARN_ON(!port))
 702                 return -ENODEV;
 703 
 704         tty_unregister_device(vcc_tty_driver, port->index);
 705 
 706         del_timer_sync(&port->vio.timer);
 707         vio_ldc_free(&port->vio);
 708         sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
 709         dev_set_drvdata(&vdev->dev, NULL);
 710         if (port->tty) {
 711                 port->removed = true;
 712                 vcc_put(port, true);
 713         } else {
 714                 vcc_table_remove(port->index);
 715 
 716                 kfree(port->vio.name);
 717                 kfree(port->domain);
 718                 kfree(port);
 719         }
 720 
 721         return 0;
 722 }
 723 
 724 static const struct vio_device_id vcc_match[] = {
 725         {
 726                 .type = "vcc-port",
 727         },
 728         {},
 729 };
 730 MODULE_DEVICE_TABLE(vio, vcc_match);
 731 
 732 static struct vio_driver vcc_driver = {
 733         .id_table       = vcc_match,
 734         .probe          = vcc_probe,
 735         .remove         = vcc_remove,
 736         .name           = "vcc",
 737 };
 738 
 739 static int vcc_open(struct tty_struct *tty, struct file *vcc_file)
 740 {
 741         struct vcc_port *port;
 742 
 743         if (unlikely(!tty)) {
 744                 pr_err("VCC: open: Invalid TTY handle\n");
 745                 return -ENXIO;
 746         }
 747 
 748         if (tty->count > 1)
 749                 return -EBUSY;
 750 
 751         port = vcc_get_ne(tty->index);
 752         if (unlikely(!port)) {
 753                 pr_err("VCC: open: Failed to find VCC port\n");
 754                 return -ENODEV;
 755         }
 756 
 757         if (unlikely(!port->vio.lp)) {
 758                 pr_err("VCC: open: LDC channel not configured\n");
 759                 vcc_put(port, false);
 760                 return -EPIPE;
 761         }
 762         vccdbgl(port->vio.lp);
 763 
 764         vcc_put(port, false);
 765 
 766         if (unlikely(!tty->port)) {
 767                 pr_err("VCC: open: TTY port not found\n");
 768                 return -ENXIO;
 769         }
 770 
 771         if (unlikely(!tty->port->ops)) {
 772                 pr_err("VCC: open: TTY ops not defined\n");
 773                 return -ENXIO;
 774         }
 775 
 776         return tty_port_open(tty->port, tty, vcc_file);
 777 }
 778 
 779 static void vcc_close(struct tty_struct *tty, struct file *vcc_file)
 780 {
 781         if (unlikely(!tty)) {
 782                 pr_err("VCC: close: Invalid TTY handle\n");
 783                 return;
 784         }
 785 
 786         if (unlikely(tty->count > 1))
 787                 return;
 788 
 789         if (unlikely(!tty->port)) {
 790                 pr_err("VCC: close: TTY port not found\n");
 791                 return;
 792         }
 793 
 794         tty_port_close(tty->port, tty, vcc_file);
 795 }
 796 
 797 static void vcc_ldc_hup(struct vcc_port *port)
 798 {
 799         unsigned long flags;
 800 
 801         spin_lock_irqsave(&port->lock, flags);
 802 
 803         if (vcc_send_ctl(port, VCC_CTL_HUP) < 0)
 804                 vcc_kick_tx(port);
 805 
 806         spin_unlock_irqrestore(&port->lock, flags);
 807 }
 808 
 809 static void vcc_hangup(struct tty_struct *tty)
 810 {
 811         struct vcc_port *port;
 812 
 813         if (unlikely(!tty)) {
 814                 pr_err("VCC: hangup: Invalid TTY handle\n");
 815                 return;
 816         }
 817 
 818         port = vcc_get_ne(tty->index);
 819         if (unlikely(!port)) {
 820                 pr_err("VCC: hangup: Failed to find VCC port\n");
 821                 return;
 822         }
 823 
 824         if (unlikely(!tty->port)) {
 825                 pr_err("VCC: hangup: TTY port not found\n");
 826                 vcc_put(port, false);
 827                 return;
 828         }
 829 
 830         vcc_ldc_hup(port);
 831 
 832         vcc_put(port, false);
 833 
 834         tty_port_hangup(tty->port);
 835 }
 836 
 837 static int vcc_write(struct tty_struct *tty, const unsigned char *buf,
 838                      int count)
 839 {
 840         struct vcc_port *port;
 841         struct vio_vcc *pkt;
 842         unsigned long flags;
 843         int total_sent = 0;
 844         int tosend = 0;
 845         int rv = -EINVAL;
 846 
 847         if (unlikely(!tty)) {
 848                 pr_err("VCC: write: Invalid TTY handle\n");
 849                 return -ENXIO;
 850         }
 851 
 852         port = vcc_get_ne(tty->index);
 853         if (unlikely(!port)) {
 854                 pr_err("VCC: write: Failed to find VCC port");
 855                 return -ENODEV;
 856         }
 857 
 858         spin_lock_irqsave(&port->lock, flags);
 859 
 860         pkt = &port->buffer;
 861         pkt->tag.type = VIO_TYPE_DATA;
 862 
 863         while (count > 0) {
 864                 /* Minimum of data to write and space available */
 865                 tosend = min(count, (VCC_BUFF_LEN - port->chars_in_buffer));
 866 
 867                 if (!tosend)
 868                         break;
 869 
 870                 memcpy(&pkt->data[port->chars_in_buffer], &buf[total_sent],
 871                        tosend);
 872                 port->chars_in_buffer += tosend;
 873                 pkt->tag.stype = tosend;
 874 
 875                 vccdbg("TAG [%02x:%02x:%04x:%08x]\n", pkt->tag.type,
 876                        pkt->tag.stype, pkt->tag.stype_env, pkt->tag.sid);
 877                 vccdbg("DATA [%s]\n", pkt->data);
 878                 vccdbgl(port->vio.lp);
 879 
 880                 /* Since we know we have enough room in VCC buffer for tosend
 881                  * we record that it was sent regardless of whether the
 882                  * hypervisor actually took it because we have it buffered.
 883                  */
 884                 rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
 885                 vccdbg("VCC: write: ldc_write(%d)=%d\n",
 886                        (VIO_TAG_SIZE + tosend), rv);
 887 
 888                 total_sent += tosend;
 889                 count -= tosend;
 890                 if (rv < 0) {
 891                         vcc_kick_tx(port);
 892                         break;
 893                 }
 894 
 895                 port->chars_in_buffer = 0;
 896         }
 897 
 898         spin_unlock_irqrestore(&port->lock, flags);
 899 
 900         vcc_put(port, false);
 901 
 902         vccdbg("VCC: write: total=%d rv=%d", total_sent, rv);
 903 
 904         return total_sent ? total_sent : rv;
 905 }
 906 
 907 static int vcc_write_room(struct tty_struct *tty)
 908 {
 909         struct vcc_port *port;
 910         u64 num;
 911 
 912         if (unlikely(!tty)) {
 913                 pr_err("VCC: write_room: Invalid TTY handle\n");
 914                 return -ENXIO;
 915         }
 916 
 917         port = vcc_get_ne(tty->index);
 918         if (unlikely(!port)) {
 919                 pr_err("VCC: write_room: Failed to find VCC port\n");
 920                 return -ENODEV;
 921         }
 922 
 923         num = VCC_BUFF_LEN - port->chars_in_buffer;
 924 
 925         vcc_put(port, false);
 926 
 927         return num;
 928 }
 929 
 930 static int vcc_chars_in_buffer(struct tty_struct *tty)
 931 {
 932         struct vcc_port *port;
 933         u64 num;
 934 
 935         if (unlikely(!tty)) {
 936                 pr_err("VCC: chars_in_buffer: Invalid TTY handle\n");
 937                 return -ENXIO;
 938         }
 939 
 940         port = vcc_get_ne(tty->index);
 941         if (unlikely(!port)) {
 942                 pr_err("VCC: chars_in_buffer: Failed to find VCC port\n");
 943                 return -ENODEV;
 944         }
 945 
 946         num = port->chars_in_buffer;
 947 
 948         vcc_put(port, false);
 949 
 950         return num;
 951 }
 952 
 953 static int vcc_break_ctl(struct tty_struct *tty, int state)
 954 {
 955         struct vcc_port *port;
 956         unsigned long flags;
 957 
 958         if (unlikely(!tty)) {
 959                 pr_err("VCC: break_ctl: Invalid TTY handle\n");
 960                 return -ENXIO;
 961         }
 962 
 963         port = vcc_get_ne(tty->index);
 964         if (unlikely(!port)) {
 965                 pr_err("VCC: break_ctl: Failed to find VCC port\n");
 966                 return -ENODEV;
 967         }
 968 
 969         /* Turn off break */
 970         if (state == 0) {
 971                 vcc_put(port, false);
 972                 return 0;
 973         }
 974 
 975         spin_lock_irqsave(&port->lock, flags);
 976 
 977         if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
 978                 vcc_kick_tx(port);
 979 
 980         spin_unlock_irqrestore(&port->lock, flags);
 981 
 982         vcc_put(port, false);
 983 
 984         return 0;
 985 }
 986 
 987 static int vcc_install(struct tty_driver *driver, struct tty_struct *tty)
 988 {
 989         struct vcc_port *port_vcc;
 990         struct tty_port *port_tty;
 991         int ret;
 992 
 993         if (unlikely(!tty)) {
 994                 pr_err("VCC: install: Invalid TTY handle\n");
 995                 return -ENXIO;
 996         }
 997 
 998         if (tty->index >= VCC_MAX_PORTS)
 999                 return -EINVAL;
1000 
1001         ret = tty_standard_install(driver, tty);
1002         if (ret)
1003                 return ret;
1004 
1005         port_tty = kzalloc(sizeof(struct tty_port), GFP_KERNEL);
1006         if (!port_tty)
1007                 return -ENOMEM;
1008 
1009         port_vcc = vcc_get(tty->index, true);
1010         if (!port_vcc) {
1011                 pr_err("VCC: install: Failed to find VCC port\n");
1012                 tty->port = NULL;
1013                 kfree(port_tty);
1014                 return -ENODEV;
1015         }
1016 
1017         tty_port_init(port_tty);
1018         port_tty->ops = &vcc_port_ops;
1019         tty->port = port_tty;
1020 
1021         port_vcc->tty = tty;
1022 
1023         vcc_put(port_vcc, true);
1024 
1025         return 0;
1026 }
1027 
1028 static void vcc_cleanup(struct tty_struct *tty)
1029 {
1030         struct vcc_port *port;
1031 
1032         if (unlikely(!tty)) {
1033                 pr_err("VCC: cleanup: Invalid TTY handle\n");
1034                 return;
1035         }
1036 
1037         port = vcc_get(tty->index, true);
1038         if (port) {
1039                 port->tty = NULL;
1040 
1041                 if (port->removed) {
1042                         vcc_table_remove(tty->index);
1043                         kfree(port->vio.name);
1044                         kfree(port->domain);
1045                         kfree(port);
1046                 } else {
1047                         vcc_put(port, true);
1048                 }
1049         }
1050 
1051         tty_port_destroy(tty->port);
1052         kfree(tty->port);
1053         tty->port = NULL;
1054 }
1055 
1056 static const struct tty_operations vcc_ops = {
1057         .open                   = vcc_open,
1058         .close                  = vcc_close,
1059         .hangup                 = vcc_hangup,
1060         .write                  = vcc_write,
1061         .write_room             = vcc_write_room,
1062         .chars_in_buffer        = vcc_chars_in_buffer,
1063         .break_ctl              = vcc_break_ctl,
1064         .install                = vcc_install,
1065         .cleanup                = vcc_cleanup,
1066 };
1067 
1068 #define VCC_TTY_FLAGS   (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
1069 
1070 static int vcc_tty_init(void)
1071 {
1072         int rv;
1073 
1074         pr_info("VCC: %s\n", version);
1075 
1076         vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
1077         if (IS_ERR(vcc_tty_driver)) {
1078                 pr_err("VCC: TTY driver alloc failed\n");
1079                 return PTR_ERR(vcc_tty_driver);
1080         }
1081 
1082         vcc_tty_driver->driver_name = vcc_driver_name;
1083         vcc_tty_driver->name = vcc_device_node;
1084 
1085         vcc_tty_driver->minor_start = VCC_MINOR_START;
1086         vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1087         vcc_tty_driver->init_termios = vcc_tty_termios;
1088 
1089         tty_set_operations(vcc_tty_driver, &vcc_ops);
1090 
1091         rv = tty_register_driver(vcc_tty_driver);
1092         if (rv) {
1093                 pr_err("VCC: TTY driver registration failed\n");
1094                 put_tty_driver(vcc_tty_driver);
1095                 vcc_tty_driver = NULL;
1096                 return rv;
1097         }
1098 
1099         vccdbg("VCC: TTY driver registered\n");
1100 
1101         return 0;
1102 }
1103 
1104 static void vcc_tty_exit(void)
1105 {
1106         tty_unregister_driver(vcc_tty_driver);
1107         put_tty_driver(vcc_tty_driver);
1108         vccdbg("VCC: TTY driver unregistered\n");
1109 
1110         vcc_tty_driver = NULL;
1111 }
1112 
1113 static int __init vcc_init(void)
1114 {
1115         int rv;
1116 
1117         rv = vcc_tty_init();
1118         if (rv) {
1119                 pr_err("VCC: TTY init failed\n");
1120                 return rv;
1121         }
1122 
1123         rv = vio_register_driver(&vcc_driver);
1124         if (rv) {
1125                 pr_err("VCC: VIO driver registration failed\n");
1126                 vcc_tty_exit();
1127         } else {
1128                 vccdbg("VCC: VIO driver registered successfully\n");
1129         }
1130 
1131         return rv;
1132 }
1133 
1134 static void __exit vcc_exit(void)
1135 {
1136         vio_unregister_driver(&vcc_driver);
1137         vccdbg("VCC: VIO driver unregistered\n");
1138         vcc_tty_exit();
1139         vccdbg("VCC: TTY driver unregistered\n");
1140 }
1141 
1142 module_init(vcc_init);
1143 module_exit(vcc_exit);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/tty/vcc.c

DEFINITIONS
