arch/ppc64/kernel/viopath.c

   1 /* -*- linux-c -*-
   2  *  arch/ppc64/kernel/viopath.c
   3  *
   4  *  iSeries Virtual I/O Message Path code
   5  *
   6  *  Authors: Dave Boutcher <boutcher@us.ibm.com>
   7  *           Ryan Arnold <ryanarn@us.ibm.com>
   8  *           Colin Devilbiss <devilbis@us.ibm.com>
   9  *
  10  * (C) Copyright 2000-2003 IBM Corporation
  11  *
  12  * This code is used by the iSeries virtual disk, cd,
  13  * tape, and console to communicate with OS/400 in another
  14  * partition.
  15  *
  16  * This program is free software;  you can redistribute it and/or
  17  * modify it under the terms of the GNU General Public License as
  18  * published by the Free Software Foundation; either version 2 of the
  19  * License, or (at your option) anyu later version.
  20  *
  21  * This program is distributed in the hope that it will be useful, but
  22  * WITHOUT ANY WARRANTY; without even the implied warranty of
  23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  24  * General Public License for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License
  27  * along with this program; if not, write to the Free Software Foundation,
  28  * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  29  *
  30  */
  31 #include <linux/module.h>
  32 #include <linux/kernel.h>
  33 #include <linux/errno.h>
  34 #include <linux/vmalloc.h>
  35 #include <linux/string.h>
  36 #include <linux/proc_fs.h>
  37 #include <linux/dma-mapping.h>
  38 #include <linux/wait.h>
  39 #include <linux/seq_file.h>
  40
  41 #include <asm/hardirq.h>
  42 #include <asm/uaccess.h>
  43 #include <asm/iSeries/LparData.h>
  44 #include <asm/iSeries/HvLpEvent.h>
  45 #include <asm/iSeries/HvLpConfig.h>
  46 #include <asm/iSeries/HvCallCfg.h>
  47 #include <asm/iSeries/mf.h>
  48 #include <asm/iSeries/iSeries_proc.h>
  49 #include <asm/iSeries/vio.h>
  50
  51 /* Status of the path to each other partition in the system.
  52  * This is overkill, since we will only ever establish connections
  53  * to our hosting partition and the primary partition on the system.
  54  * But this allows for other support in the future.
  55  */
  56 static struct viopathStatus {
  57         int isOpen:1;           /* Did we open the path?            */
  58         int isActive:1;         /* Do we have a mon msg outstanding */
  59         int users[VIO_MAX_SUBTYPES];
  60         HvLpInstanceId mSourceInst;
  61         HvLpInstanceId mTargetInst;
  62         int numberAllocated;
  63 } viopathStatus[HVMAXARCHITECTEDLPS];
  64
  65 static spinlock_t statuslock = SPIN_LOCK_UNLOCKED;
  66
  67 /*
  68  * For each kind of event we allocate a buffer that is
  69  * guaranteed not to cross a page boundary
  70  */
  71 static unsigned char event_buffer[VIO_MAX_SUBTYPES * 256] __page_aligned;
  72 static atomic_t event_buffer_available[VIO_MAX_SUBTYPES];
  73 static int event_buffer_initialised;
  74
  75 static void handleMonitorEvent(struct HvLpEvent *event);
  76
  77 /*
  78  * We use this structure to handle asynchronous responses.  The caller
  79  * blocks on the semaphore and the handler posts the semaphore.  However,
  80  * if in_atomic() is true in the caller, then wait_atomic is used ...
  81  */
  82 struct doneAllocParms_t {
  83         struct semaphore *sem;
  84         int number;
  85         atomic_t *wait_atomic;
  86         int used_wait_atomic;
  87 };
  88
  89 /* Put a sequence number in each mon msg.  The value is not
  90  * important.  Start at something other than 0 just for
  91  * readability.  wrapping this is ok.
  92  */
  93 static u8 viomonseq = 22;
  94
  95 /* Our hosting logical partition.  We get this at startup
  96  * time, and different modules access this variable directly.
  97  */
  98 HvLpIndex viopath_hostLp = 0xff;        /* HvLpIndexInvalid */
  99 EXPORT_SYMBOL(viopath_hostLp);
 100 HvLpIndex viopath_ourLp = 0xff;
 101 EXPORT_SYMBOL(viopath_ourLp);
 102
 103 /* For each kind of incoming event we set a pointer to a
 104  * routine to call.
 105  */
 106 static vio_event_handler_t *vio_handler[VIO_MAX_SUBTYPES];
 107
 108 #define VIOPATH_KERN_WARN       KERN_WARNING "viopath: "
 109 #define VIOPATH_KERN_INFO       KERN_INFO "viopath: "
 110
 111 static unsigned char e2a(unsigned char x)
 112 {
 113         switch (x) {
 114         case 0xF0:
 115                 return '0';
 116         case 0xF1:
 117                 return '1';
 118         case 0xF2:
 119                 return '2';
 120         case 0xF3:
 121                 return '3';
 122         case 0xF4:
 123                 return '4';
 124         case 0xF5:
 125                 return '5';
 126         case 0xF6:
 127                 return '6';
 128         case 0xF7:
 129                 return '7';
 130         case 0xF8:
 131                 return '8';
 132         case 0xF9:
 133                 return '9';
 134         case 0xC1:
 135                 return 'A';
 136         case 0xC2:
 137                 return 'B';
 138         case 0xC3:
 139                 return 'C';
 140         case 0xC4:
 141                 return 'D';
 142         case 0xC5:
 143                 return 'E';
 144         case 0xC6:
 145                 return 'F';
 146         case 0xC7:
 147                 return 'G';
 148         case 0xC8:
 149                 return 'H';
 150         case 0xC9:
 151                 return 'I';
 152         case 0xD1:
 153                 return 'J';
 154         case 0xD2:
 155                 return 'K';
 156         case 0xD3:
 157                 return 'L';
 158         case 0xD4:
 159                 return 'M';
 160         case 0xD5:
 161                 return 'N';
 162         case 0xD6:
 163                 return 'O';
 164         case 0xD7:
 165                 return 'P';
 166         case 0xD8:
 167                 return 'Q';
 168         case 0xD9:
 169                 return 'R';
 170         case 0xE2:
 171                 return 'S';
 172         case 0xE3:
 173                 return 'T';
 174         case 0xE4:
 175                 return 'U';
 176         case 0xE5:
 177                 return 'V';
 178         case 0xE6:
 179                 return 'W';
 180         case 0xE7:
 181                 return 'X';
 182         case 0xE8:
 183                 return 'Y';
 184         case 0xE9:
 185                 return 'Z';
 186         }
 187         return ' ';
 188 }
 189
 190 static int proc_viopath_show(struct seq_file *m, void *v)
 191 {
 192         char *buf;
 193         dma_addr_t handle;
 194         HvLpEvent_Rc hvrc;
 195         DECLARE_MUTEX_LOCKED(Semaphore);
 196
 197         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 198         if (!buf)
 199                 return 0;
 200         memset(buf, 0, PAGE_SIZE);
 201
 202         handle = dma_map_single(iSeries_vio_dev, buf, PAGE_SIZE,
 203                                 DMA_FROM_DEVICE);
 204
 205         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 206                         HvLpEvent_Type_VirtualIo,
 207                         viomajorsubtype_config | vioconfigget,
 208                         HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
 209                         viopath_sourceinst(viopath_hostLp),
 210                         viopath_targetinst(viopath_hostLp),
 211                         (u64)(unsigned long)&Semaphore, VIOVERSION << 16,
 212                         ((u64)handle) << 32, PAGE_SIZE, 0, 0);
 213
 214         if (hvrc != HvLpEvent_Rc_Good)
 215                 printk(VIOPATH_KERN_WARN "hv error on op %d\n", (int)hvrc);
 216
 217         down(&Semaphore);
 218
 219         dma_unmap_single(iSeries_vio_dev, handle, PAGE_SIZE, DMA_FROM_DEVICE);
 220         kfree(buf);
 221
 222         buf[PAGE_SIZE] = '\0';
 223         seq_printf(m, "%s", buf);
 224
 225         seq_printf(m, "SRLNBR=%c%c%c%c%c%c%c\n",
 226                    e2a(xItExtVpdPanel.mfgID[2]),
 227                    e2a(xItExtVpdPanel.mfgID[3]),
 228                    e2a(xItExtVpdPanel.systemSerial[1]),
 229                    e2a(xItExtVpdPanel.systemSerial[2]),
 230                    e2a(xItExtVpdPanel.systemSerial[3]),
 231                    e2a(xItExtVpdPanel.systemSerial[4]),
 232                    e2a(xItExtVpdPanel.systemSerial[5]));
 233
 234         return 0;
 235 }
 236
 237 static int proc_viopath_open(struct inode *inode, struct file *file)
 238 {
 239         return single_open(file, proc_viopath_show, NULL);
 240 }
 241
 242 static struct file_operations proc_viopath_operations = {
 243         .open           = proc_viopath_open,
 244         .read           = seq_read,
 245         .llseek         = seq_lseek,
 246         .release        = single_release,
 247 };
 248
 249 static int __init vio_proc_init(void)
 250 {
 251         struct proc_dir_entry *e;
 252
 253         e = create_proc_entry("iSeries/config", 0, NULL);
 254         if (e)
 255                 e->proc_fops = &proc_viopath_operations;
 256
 257         return 0;
 258 }
 259 __initcall(vio_proc_init);
 260
 261 /* See if a given LP is active.  Allow for invalid lps to be passed in
 262  * and just return invalid
 263  */
 264 int viopath_isactive(HvLpIndex lp)
 265 {
 266         if (lp == HvLpIndexInvalid)
 267                 return 0;
 268         if (lp < HVMAXARCHITECTEDLPS)
 269                 return viopathStatus[lp].isActive;
 270         else
 271                 return 0;
 272 }
 273 EXPORT_SYMBOL(viopath_isactive);
 274
 275 /*
 276  * We cache the source and target instance ids for each
 277  * partition.
 278  */
 279 HvLpInstanceId viopath_sourceinst(HvLpIndex lp)
 280 {
 281         return viopathStatus[lp].mSourceInst;
 282 }
 283 EXPORT_SYMBOL(viopath_sourceinst);
 284
 285 HvLpInstanceId viopath_targetinst(HvLpIndex lp)
 286 {
 287         return viopathStatus[lp].mTargetInst;
 288 }
 289 EXPORT_SYMBOL(viopath_targetinst);
 290
 291 /*
 292  * Send a monitor message.  This is a message with the acknowledge
 293  * bit on that the other side will NOT explicitly acknowledge.  When
 294  * the other side goes down, the hypervisor will acknowledge any
 295  * outstanding messages....so we will know when the other side dies.
 296  */
 297 static void sendMonMsg(HvLpIndex remoteLp)
 298 {
 299         HvLpEvent_Rc hvrc;
 300
 301         viopathStatus[remoteLp].mSourceInst =
 302                 HvCallEvent_getSourceLpInstanceId(remoteLp,
 303                                 HvLpEvent_Type_VirtualIo);
 304         viopathStatus[remoteLp].mTargetInst =
 305                 HvCallEvent_getTargetLpInstanceId(remoteLp,
 306                                 HvLpEvent_Type_VirtualIo);
 307
 308         /*
 309          * Deliberately ignore the return code here.  if we call this
 310          * more than once, we don't care.
 311          */
 312         vio_setHandler(viomajorsubtype_monitor, handleMonitorEvent);
 313
 314         hvrc = HvCallEvent_signalLpEventFast(remoteLp, HvLpEvent_Type_VirtualIo,
 315                         viomajorsubtype_monitor, HvLpEvent_AckInd_DoAck,
 316                         HvLpEvent_AckType_DeferredAck,
 317                         viopathStatus[remoteLp].mSourceInst,
 318                         viopathStatus[remoteLp].mTargetInst,
 319                         viomonseq++, 0, 0, 0, 0, 0);
 320
 321         if (hvrc == HvLpEvent_Rc_Good)
 322                 viopathStatus[remoteLp].isActive = 1;
 323         else {
 324                 printk(VIOPATH_KERN_WARN "could not connect to partition %d\n",
 325                                 remoteLp);
 326                 viopathStatus[remoteLp].isActive = 0;
 327         }
 328 }
 329
 330 static void handleMonitorEvent(struct HvLpEvent *event)
 331 {
 332         HvLpIndex remoteLp;
 333         int i;
 334
 335         /*
 336          * This handler is _also_ called as part of the loop
 337          * at the end of this routine, so it must be able to
 338          * ignore NULL events...
 339          */
 340         if (!event)
 341                 return;
 342
 343         /*
 344          * First see if this is just a normal monitor message from the
 345          * other partition
 346          */
 347         if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
 348                 remoteLp = event->xSourceLp;
 349                 if (!viopathStatus[remoteLp].isActive)
 350                         sendMonMsg(remoteLp);
 351                 return;
 352         }
 353
 354         /*
 355          * This path is for an acknowledgement; the other partition
 356          * died
 357          */
 358         remoteLp = event->xTargetLp;
 359         if ((event->xSourceInstanceId != viopathStatus[remoteLp].mSourceInst) ||
 360             (event->xTargetInstanceId != viopathStatus[remoteLp].mTargetInst)) {
 361                 printk(VIOPATH_KERN_WARN "ignoring ack....mismatched instances\n");
 362                 return;
 363         }
 364
 365         printk(VIOPATH_KERN_WARN "partition %d ended\n", remoteLp);
 366
 367         viopathStatus[remoteLp].isActive = 0;
 368
 369         /*
 370          * For each active handler, pass them a NULL
 371          * message to indicate that the other partition
 372          * died
 373          */
 374         for (i = 0; i < VIO_MAX_SUBTYPES; i++) {
 375                 if (vio_handler[i] != NULL)
 376                         (*vio_handler[i])(NULL);
 377         }
 378 }
 379
 380 int vio_setHandler(int subtype, vio_event_handler_t *beh)
 381 {
 382         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 383         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 384                 return -EINVAL;
 385         if (vio_handler[subtype] != NULL)
 386                 return -EBUSY;
 387         vio_handler[subtype] = beh;
 388         return 0;
 389 }
 390 EXPORT_SYMBOL(vio_setHandler);
 391
 392 int vio_clearHandler(int subtype)
 393 {
 394         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 395         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 396                 return -EINVAL;
 397         if (vio_handler[subtype] == NULL)
 398                 return -EAGAIN;
 399         vio_handler[subtype] = NULL;
 400         return 0;
 401 }
 402 EXPORT_SYMBOL(vio_clearHandler);
 403
 404 static void handleConfig(struct HvLpEvent *event)
 405 {
 406         if (!event)
 407                 return;
 408         if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
 409                 printk(VIOPATH_KERN_WARN
 410                        "unexpected config request from partition %d",
 411                        event->xSourceLp);
 412
 413                 if ((event->xFlags.xFunction == HvLpEvent_Function_Int) &&
 414                     (event->xFlags.xAckInd == HvLpEvent_AckInd_DoAck)) {
 415                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
 416                         HvCallEvent_ackLpEvent(event);
 417                 }
 418                 return;
 419         }
 420
 421         up((struct semaphore *)event->xCorrelationToken);
 422 }
 423
 424 /*
 425  * Initialization of the hosting partition
 426  */
 427 void vio_set_hostlp(void)
 428 {
 429         /*
 430          * If this has already been set then we DON'T want to either change
 431          * it or re-register the proc file system
 432          */
 433         if (viopath_hostLp != HvLpIndexInvalid)
 434                 return;
 435
 436         /*
 437          * Figure out our hosting partition.  This isn't allowed to change
 438          * while we're active
 439          */
 440         viopath_ourLp = HvLpConfig_getLpIndex();
 441         viopath_hostLp = HvCallCfg_getHostingLpIndex(viopath_ourLp);
 442
 443         if (viopath_hostLp != HvLpIndexInvalid)
 444                 vio_setHandler(viomajorsubtype_config, handleConfig);
 445 }
 446 EXPORT_SYMBOL(vio_set_hostlp);
 447
 448 static void vio_handleEvent(struct HvLpEvent *event, struct pt_regs *regs)
 449 {
 450         HvLpIndex remoteLp;
 451         int subtype = (event->xSubtype & VIOMAJOR_SUBTYPE_MASK)
 452                 >> VIOMAJOR_SUBTYPE_SHIFT;
 453
 454         if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
 455                 remoteLp = event->xSourceLp;
 456                 /*
 457                  * The isActive is checked because if the hosting partition
 458                  * went down and came back up it would not be active but it
 459                  * would have different source and target instances, in which
 460                  * case we'd want to reset them.  This case really protects
 461                  * against an unauthorized active partition sending interrupts
 462                  * or acks to this linux partition.
 463                  */
 464                 if (viopathStatus[remoteLp].isActive
 465                     && (event->xSourceInstanceId !=
 466                         viopathStatus[remoteLp].mTargetInst)) {
 467                         printk(VIOPATH_KERN_WARN
 468                                "message from invalid partition. "
 469                                "int msg rcvd, source inst (%d) doesnt match (%d)\n",
 470                                viopathStatus[remoteLp].mTargetInst,
 471                                event->xSourceInstanceId);
 472                         return;
 473                 }
 474
 475                 if (viopathStatus[remoteLp].isActive
 476                     && (event->xTargetInstanceId !=
 477                         viopathStatus[remoteLp].mSourceInst)) {
 478                         printk(VIOPATH_KERN_WARN
 479                                "message from invalid partition. "
 480                                "int msg rcvd, target inst (%d) doesnt match (%d)\n",
 481                                viopathStatus[remoteLp].mSourceInst,
 482                                event->xTargetInstanceId);
 483                         return;
 484                 }
 485         } else {
 486                 remoteLp = event->xTargetLp;
 487                 if (event->xSourceInstanceId !=
 488                     viopathStatus[remoteLp].mSourceInst) {
 489                         printk(VIOPATH_KERN_WARN
 490                                "message from invalid partition. "
 491                                "ack msg rcvd, source inst (%d) doesnt match (%d)\n",
 492                                viopathStatus[remoteLp].mSourceInst,
 493                                event->xSourceInstanceId);
 494                         return;
 495                 }
 496
 497                 if (event->xTargetInstanceId !=
 498                     viopathStatus[remoteLp].mTargetInst) {
 499                         printk(VIOPATH_KERN_WARN
 500                                "message from invalid partition. "
 501                                "viopath: ack msg rcvd, target inst (%d) doesnt match (%d)\n",
 502                                viopathStatus[remoteLp].mTargetInst,
 503                                event->xTargetInstanceId);
 504                         return;
 505                 }
 506         }
 507
 508         if (vio_handler[subtype] == NULL) {
 509                 printk(VIOPATH_KERN_WARN
 510                        "unexpected virtual io event subtype %d from partition %d\n",
 511                        event->xSubtype, remoteLp);
 512                 /* No handler.  Ack if necessary */
 513                 if ((event->xFlags.xFunction == HvLpEvent_Function_Int) &&
 514                     (event->xFlags.xAckInd == HvLpEvent_AckInd_DoAck)) {
 515                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
 516                         HvCallEvent_ackLpEvent(event);
 517                 }
 518                 return;
 519         }
 520
 521         /* This innocuous little line is where all the real work happens */
 522         (*vio_handler[subtype])(event);
 523 }
 524
 525 static void viopath_donealloc(void *parm, int number)
 526 {
 527         struct doneAllocParms_t *parmsp = (struct doneAllocParms_t *)parm;
 528
 529         parmsp->number = number;
 530         if (parmsp->used_wait_atomic)
 531                 atomic_set(parmsp->wait_atomic, 0);
 532         else
 533                 up(parmsp->sem);
 534 }
 535
 536 static int allocateEvents(HvLpIndex remoteLp, int numEvents)
 537 {
 538         struct doneAllocParms_t parms;
 539         DECLARE_MUTEX_LOCKED(Semaphore);
 540         atomic_t wait_atomic;
 541
 542         if (in_atomic()) {
 543                 parms.used_wait_atomic = 1;
 544                 atomic_set(&wait_atomic, 1);
 545                 parms.wait_atomic = &wait_atomic;
 546         } else {
 547                 parms.used_wait_atomic = 0;
 548                 parms.sem = &Semaphore;
 549         }
 550         mf_allocateLpEvents(remoteLp, HvLpEvent_Type_VirtualIo, 250,    /* It would be nice to put a real number here! */
 551                             numEvents, &viopath_donealloc, &parms);
 552         if (in_atomic()) {
 553                 while (atomic_read(&wait_atomic))
 554                         mb();
 555         } else
 556                 down(&Semaphore);
 557         return parms.number;
 558 }
 559
 560 int viopath_open(HvLpIndex remoteLp, int subtype, int numReq)
 561 {
 562         int i;
 563         unsigned long flags;
 564         int tempNumAllocated;
 565
 566         if ((remoteLp >= HvMaxArchitectedLps) || (remoteLp == HvLpIndexInvalid))
 567                 return -EINVAL;
 568
 569         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 570         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 571                 return -EINVAL;
 572
 573         spin_lock_irqsave(&statuslock, flags);
 574
 575         if (!event_buffer_initialised) {
 576                 for (i = 0; i < VIO_MAX_SUBTYPES; i++)
 577                         atomic_set(&event_buffer_available[i], 1);
 578                 event_buffer_initialised = 1;
 579         }
 580
 581         viopathStatus[remoteLp].users[subtype]++;
 582
 583         if (!viopathStatus[remoteLp].isOpen) {
 584                 viopathStatus[remoteLp].isOpen = 1;
 585                 HvCallEvent_openLpEventPath(remoteLp, HvLpEvent_Type_VirtualIo);
 586
 587                 /*
 588                  * Don't hold the spinlock during an operation that
 589                  * can sleep.
 590                  */
 591                 spin_unlock_irqrestore(&statuslock, flags);
 592                 tempNumAllocated = allocateEvents(remoteLp, 1);
 593                 spin_lock_irqsave(&statuslock, flags);
 594
 595                 viopathStatus[remoteLp].numberAllocated += tempNumAllocated;
 596
 597                 if (viopathStatus[remoteLp].numberAllocated == 0) {
 598                         HvCallEvent_closeLpEventPath(remoteLp,
 599                                         HvLpEvent_Type_VirtualIo);
 600
 601                         spin_unlock_irqrestore(&statuslock, flags);
 602                         return -ENOMEM;
 603                 }
 604
 605                 viopathStatus[remoteLp].mSourceInst =
 606                         HvCallEvent_getSourceLpInstanceId(remoteLp,
 607                                         HvLpEvent_Type_VirtualIo);
 608                 viopathStatus[remoteLp].mTargetInst =
 609                         HvCallEvent_getTargetLpInstanceId(remoteLp,
 610                                         HvLpEvent_Type_VirtualIo);
 611                 HvLpEvent_registerHandler(HvLpEvent_Type_VirtualIo,
 612                                           &vio_handleEvent);
 613                 sendMonMsg(remoteLp);
 614                 printk(VIOPATH_KERN_INFO "opening connection to partition %d, "
 615                                 "setting sinst %d, tinst %d\n",
 616                                 remoteLp, viopathStatus[remoteLp].mSourceInst,
 617                                 viopathStatus[remoteLp].mTargetInst);
 618         }
 619
 620         spin_unlock_irqrestore(&statuslock, flags);
 621         tempNumAllocated = allocateEvents(remoteLp, numReq);
 622         spin_lock_irqsave(&statuslock, flags);
 623         viopathStatus[remoteLp].numberAllocated += tempNumAllocated;
 624         spin_unlock_irqrestore(&statuslock, flags);
 625
 626         return 0;
 627 }
 628 EXPORT_SYMBOL(viopath_open);
 629
 630 int viopath_close(HvLpIndex remoteLp, int subtype, int numReq)
 631 {
 632         unsigned long flags;
 633         int i;
 634         int numOpen;
 635         struct doneAllocParms_t doneAllocParms;
 636         DECLARE_MUTEX_LOCKED(Semaphore);
 637
 638         if ((remoteLp >= HvMaxArchitectedLps) || (remoteLp == HvLpIndexInvalid))
 639                 return -EINVAL;
 640
 641         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 642         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 643                 return -EINVAL;
 644
 645         spin_lock_irqsave(&statuslock, flags);
 646         /*
 647          * If the viopath_close somehow gets called before a
 648          * viopath_open it could decrement to -1 which is a non
 649          * recoverable state so we'll prevent this from
 650          * happening.
 651          */
 652         if (viopathStatus[remoteLp].users[subtype] > 0)
 653                 viopathStatus[remoteLp].users[subtype]--;
 654
 655         spin_unlock_irqrestore(&statuslock, flags);
 656
 657         doneAllocParms.used_wait_atomic = 0;
 658         doneAllocParms.sem = &Semaphore;
 659         mf_deallocateLpEvents(remoteLp, HvLpEvent_Type_VirtualIo,
 660                               numReq, &viopath_donealloc, &doneAllocParms);
 661         down(&Semaphore);
 662
 663         spin_lock_irqsave(&statuslock, flags);
 664         for (i = 0, numOpen = 0; i < VIO_MAX_SUBTYPES; i++)
 665                 numOpen += viopathStatus[remoteLp].users[i];
 666
 667         if ((viopathStatus[remoteLp].isOpen) && (numOpen == 0)) {
 668                 printk(VIOPATH_KERN_INFO "closing connection to partition %d",
 669                                 remoteLp);
 670
 671                 HvCallEvent_closeLpEventPath(remoteLp,
 672                                              HvLpEvent_Type_VirtualIo);
 673                 viopathStatus[remoteLp].isOpen = 0;
 674                 viopathStatus[remoteLp].isActive = 0;
 675
 676                 for (i = 0; i < VIO_MAX_SUBTYPES; i++)
 677                         atomic_set(&event_buffer_available[i], 0);
 678                 event_buffer_initialised = 0;
 679         }
 680         spin_unlock_irqrestore(&statuslock, flags);
 681         return 0;
 682 }
 683 EXPORT_SYMBOL(viopath_close);
 684
 685 void *vio_get_event_buffer(int subtype)
 686 {
 687         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 688         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 689                 return NULL;
 690
 691         if (atomic_dec_if_positive(&event_buffer_available[subtype]) == 0)
 692                 return &event_buffer[subtype * 256];
 693         else
 694                 return NULL;
 695 }
 696 EXPORT_SYMBOL(vio_get_event_buffer);
 697
 698 void vio_free_event_buffer(int subtype, void *buffer)
 699 {
 700         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 701         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES)) {
 702                 printk(VIOPATH_KERN_WARN
 703                        "unexpected subtype %d freeing event buffer\n", subtype);
 704                 return;
 705         }
 706
 707         if (atomic_read(&event_buffer_available[subtype]) != 0) {
 708                 printk(VIOPATH_KERN_WARN
 709                        "freeing unallocated event buffer, subtype %d\n",
 710                        subtype);
 711                 return;
 712         }
 713
 714         if (buffer != &event_buffer[subtype * 256]) {
 715                 printk(VIOPATH_KERN_WARN
 716                        "freeing invalid event buffer, subtype %d\n", subtype);
 717         }
 718
 719         atomic_set(&event_buffer_available[subtype], 1);
 720 }
 721 EXPORT_SYMBOL(vio_free_event_buffer);
 722
 723 static const struct vio_error_entry vio_no_error =
 724     { 0, 0, "Non-VIO Error" };
 725 static const struct vio_error_entry vio_unknown_error =
 726     { 0, EIO, "Unknown Error" };
 727
 728 static const struct vio_error_entry vio_default_errors[] = {
 729         {0x0001, EIO, "No Connection"},
 730         {0x0002, EIO, "No Receiver"},
 731         {0x0003, EIO, "No Buffer Available"},
 732         {0x0004, EBADRQC, "Invalid Message Type"},
 733         {0x0000, 0, NULL},
 734 };
 735
 736 const struct vio_error_entry *vio_lookup_rc(
 737                 const struct vio_error_entry *local_table, u16 rc)
 738 {
 739         const struct vio_error_entry *cur;
 740
 741         if (!rc)
 742                 return &vio_no_error;
 743         if (local_table)
 744                 for (cur = local_table; cur->rc; ++cur)
 745                         if (cur->rc == rc)
 746                                 return cur;
 747         for (cur = vio_default_errors; cur->rc; ++cur)
 748                 if (cur->rc == rc)
 749                         return cur;
 750         return &vio_unknown_error;
 751 }
 752 EXPORT_SYMBOL(vio_lookup_rc);