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         u16 vlanMap;
 194         dma_addr_t handle;
 195         HvLpEvent_Rc hvrc;
 196         DECLARE_MUTEX_LOCKED(Semaphore);
 197
 198         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 199         if (!buf)
 200                 return 0;
 201         memset(buf, 0, PAGE_SIZE);
 202
 203         handle = dma_map_single(iSeries_vio_dev, buf, PAGE_SIZE,
 204                                 DMA_FROM_DEVICE);
 205
 206         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 207                         HvLpEvent_Type_VirtualIo,
 208                         viomajorsubtype_config | vioconfigget,
 209                         HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
 210                         viopath_sourceinst(viopath_hostLp),
 211                         viopath_targetinst(viopath_hostLp),
 212                         (u64)(unsigned long)&Semaphore, VIOVERSION << 16,
 213                         ((u64)handle) << 32, PAGE_SIZE, 0, 0);
 214
 215         if (hvrc != HvLpEvent_Rc_Good)
 216                 printk(VIOPATH_KERN_WARN "hv error on op %d\n", (int)hvrc);
 217
 218         down(&Semaphore);
 219
 220         vlanMap = HvLpConfig_getVirtualLanIndexMap();
 221
 222         buf[PAGE_SIZE-1] = '\0';
 223         seq_printf(m, "%s", buf);
 224         seq_printf(m, "AVAILABLE_VETH=%x\n", vlanMap);
 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         dma_unmap_single(iSeries_vio_dev, handle, PAGE_SIZE, DMA_FROM_DEVICE);
 235         kfree(buf);
 236
 237         return 0;
 238 }
 239
 240 static int proc_viopath_open(struct inode *inode, struct file *file)
 241 {
 242         return single_open(file, proc_viopath_show, NULL);
 243 }
 244
 245 static struct file_operations proc_viopath_operations = {
 246         .open           = proc_viopath_open,
 247         .read           = seq_read,
 248         .llseek         = seq_lseek,
 249         .release        = single_release,
 250 };
 251
 252 static int __init vio_proc_init(void)
 253 {
 254         struct proc_dir_entry *e;
 255
 256         e = create_proc_entry("iSeries/config", 0, NULL);
 257         if (e)
 258                 e->proc_fops = &proc_viopath_operations;
 259
 260         return 0;
 261 }
 262 __initcall(vio_proc_init);
 263
 264 /* See if a given LP is active.  Allow for invalid lps to be passed in
 265  * and just return invalid
 266  */
 267 int viopath_isactive(HvLpIndex lp)
 268 {
 269         if (lp == HvLpIndexInvalid)
 270                 return 0;
 271         if (lp < HVMAXARCHITECTEDLPS)
 272                 return viopathStatus[lp].isActive;
 273         else
 274                 return 0;
 275 }
 276 EXPORT_SYMBOL(viopath_isactive);
 277
 278 /*
 279  * We cache the source and target instance ids for each
 280  * partition.
 281  */
 282 HvLpInstanceId viopath_sourceinst(HvLpIndex lp)
 283 {
 284         return viopathStatus[lp].mSourceInst;
 285 }
 286 EXPORT_SYMBOL(viopath_sourceinst);
 287
 288 HvLpInstanceId viopath_targetinst(HvLpIndex lp)
 289 {
 290         return viopathStatus[lp].mTargetInst;
 291 }
 292 EXPORT_SYMBOL(viopath_targetinst);
 293
 294 /*
 295  * Send a monitor message.  This is a message with the acknowledge
 296  * bit on that the other side will NOT explicitly acknowledge.  When
 297  * the other side goes down, the hypervisor will acknowledge any
 298  * outstanding messages....so we will know when the other side dies.
 299  */
 300 static void sendMonMsg(HvLpIndex remoteLp)
 301 {
 302         HvLpEvent_Rc hvrc;
 303
 304         viopathStatus[remoteLp].mSourceInst =
 305                 HvCallEvent_getSourceLpInstanceId(remoteLp,
 306                                 HvLpEvent_Type_VirtualIo);
 307         viopathStatus[remoteLp].mTargetInst =
 308                 HvCallEvent_getTargetLpInstanceId(remoteLp,
 309                                 HvLpEvent_Type_VirtualIo);
 310
 311         /*
 312          * Deliberately ignore the return code here.  if we call this
 313          * more than once, we don't care.
 314          */
 315         vio_setHandler(viomajorsubtype_monitor, handleMonitorEvent);
 316
 317         hvrc = HvCallEvent_signalLpEventFast(remoteLp, HvLpEvent_Type_VirtualIo,
 318                         viomajorsubtype_monitor, HvLpEvent_AckInd_DoAck,
 319                         HvLpEvent_AckType_DeferredAck,
 320                         viopathStatus[remoteLp].mSourceInst,
 321                         viopathStatus[remoteLp].mTargetInst,
 322                         viomonseq++, 0, 0, 0, 0, 0);
 323
 324         if (hvrc == HvLpEvent_Rc_Good)
 325                 viopathStatus[remoteLp].isActive = 1;
 326         else {
 327                 printk(VIOPATH_KERN_WARN "could not connect to partition %d\n",
 328                                 remoteLp);
 329                 viopathStatus[remoteLp].isActive = 0;
 330         }
 331 }
 332
 333 static void handleMonitorEvent(struct HvLpEvent *event)
 334 {
 335         HvLpIndex remoteLp;
 336         int i;
 337
 338         /*
 339          * This handler is _also_ called as part of the loop
 340          * at the end of this routine, so it must be able to
 341          * ignore NULL events...
 342          */
 343         if (!event)
 344                 return;
 345
 346         /*
 347          * First see if this is just a normal monitor message from the
 348          * other partition
 349          */
 350         if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
 351                 remoteLp = event->xSourceLp;
 352                 if (!viopathStatus[remoteLp].isActive)
 353                         sendMonMsg(remoteLp);
 354                 return;
 355         }
 356
 357         /*
 358          * This path is for an acknowledgement; the other partition
 359          * died
 360          */
 361         remoteLp = event->xTargetLp;
 362         if ((event->xSourceInstanceId != viopathStatus[remoteLp].mSourceInst) ||
 363             (event->xTargetInstanceId != viopathStatus[remoteLp].mTargetInst)) {
 364                 printk(VIOPATH_KERN_WARN "ignoring ack....mismatched instances\n");
 365                 return;
 366         }
 367
 368         printk(VIOPATH_KERN_WARN "partition %d ended\n", remoteLp);
 369
 370         viopathStatus[remoteLp].isActive = 0;
 371
 372         /*
 373          * For each active handler, pass them a NULL
 374          * message to indicate that the other partition
 375          * died
 376          */
 377         for (i = 0; i < VIO_MAX_SUBTYPES; i++) {
 378                 if (vio_handler[i] != NULL)
 379                         (*vio_handler[i])(NULL);
 380         }
 381 }
 382
 383 int vio_setHandler(int subtype, vio_event_handler_t *beh)
 384 {
 385         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 386         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 387                 return -EINVAL;
 388         if (vio_handler[subtype] != NULL)
 389                 return -EBUSY;
 390         vio_handler[subtype] = beh;
 391         return 0;
 392 }
 393 EXPORT_SYMBOL(vio_setHandler);
 394
 395 int vio_clearHandler(int subtype)
 396 {
 397         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 398         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 399                 return -EINVAL;
 400         if (vio_handler[subtype] == NULL)
 401                 return -EAGAIN;
 402         vio_handler[subtype] = NULL;
 403         return 0;
 404 }
 405 EXPORT_SYMBOL(vio_clearHandler);
 406
 407 static void handleConfig(struct HvLpEvent *event)
 408 {
 409         if (!event)
 410                 return;
 411         if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
 412                 printk(VIOPATH_KERN_WARN
 413                        "unexpected config request from partition %d",
 414                        event->xSourceLp);
 415
 416                 if ((event->xFlags.xFunction == HvLpEvent_Function_Int) &&
 417                     (event->xFlags.xAckInd == HvLpEvent_AckInd_DoAck)) {
 418                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
 419                         HvCallEvent_ackLpEvent(event);
 420                 }
 421                 return;
 422         }
 423
 424         up((struct semaphore *)event->xCorrelationToken);
 425 }
 426
 427 /*
 428  * Initialization of the hosting partition
 429  */
 430 void vio_set_hostlp(void)
 431 {
 432         /*
 433          * If this has already been set then we DON'T want to either change
 434          * it or re-register the proc file system
 435          */
 436         if (viopath_hostLp != HvLpIndexInvalid)
 437                 return;
 438
 439         /*
 440          * Figure out our hosting partition.  This isn't allowed to change
 441          * while we're active
 442          */
 443         viopath_ourLp = HvLpConfig_getLpIndex();
 444         viopath_hostLp = HvCallCfg_getHostingLpIndex(viopath_ourLp);
 445
 446         if (viopath_hostLp != HvLpIndexInvalid)
 447                 vio_setHandler(viomajorsubtype_config, handleConfig);
 448 }
 449 EXPORT_SYMBOL(vio_set_hostlp);
 450
 451 static void vio_handleEvent(struct HvLpEvent *event, struct pt_regs *regs)
 452 {
 453         HvLpIndex remoteLp;
 454         int subtype = (event->xSubtype & VIOMAJOR_SUBTYPE_MASK)
 455                 >> VIOMAJOR_SUBTYPE_SHIFT;
 456
 457         if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
 458                 remoteLp = event->xSourceLp;
 459                 /*
 460                  * The isActive is checked because if the hosting partition
 461                  * went down and came back up it would not be active but it
 462                  * would have different source and target instances, in which
 463                  * case we'd want to reset them.  This case really protects
 464                  * against an unauthorized active partition sending interrupts
 465                  * or acks to this linux partition.
 466                  */
 467                 if (viopathStatus[remoteLp].isActive
 468                     && (event->xSourceInstanceId !=
 469                         viopathStatus[remoteLp].mTargetInst)) {
 470                         printk(VIOPATH_KERN_WARN
 471                                "message from invalid partition. "
 472                                "int msg rcvd, source inst (%d) doesnt match (%d)\n",
 473                                viopathStatus[remoteLp].mTargetInst,
 474                                event->xSourceInstanceId);
 475                         return;
 476                 }
 477
 478                 if (viopathStatus[remoteLp].isActive
 479                     && (event->xTargetInstanceId !=
 480                         viopathStatus[remoteLp].mSourceInst)) {
 481                         printk(VIOPATH_KERN_WARN
 482                                "message from invalid partition. "
 483                                "int msg rcvd, target inst (%d) doesnt match (%d)\n",
 484                                viopathStatus[remoteLp].mSourceInst,
 485                                event->xTargetInstanceId);
 486                         return;
 487                 }
 488         } else {
 489                 remoteLp = event->xTargetLp;
 490                 if (event->xSourceInstanceId !=
 491                     viopathStatus[remoteLp].mSourceInst) {
 492                         printk(VIOPATH_KERN_WARN
 493                                "message from invalid partition. "
 494                                "ack msg rcvd, source inst (%d) doesnt match (%d)\n",
 495                                viopathStatus[remoteLp].mSourceInst,
 496                                event->xSourceInstanceId);
 497                         return;
 498                 }
 499
 500                 if (event->xTargetInstanceId !=
 501                     viopathStatus[remoteLp].mTargetInst) {
 502                         printk(VIOPATH_KERN_WARN
 503                                "message from invalid partition. "
 504                                "viopath: ack msg rcvd, target inst (%d) doesnt match (%d)\n",
 505                                viopathStatus[remoteLp].mTargetInst,
 506                                event->xTargetInstanceId);
 507                         return;
 508                 }
 509         }
 510
 511         if (vio_handler[subtype] == NULL) {
 512                 printk(VIOPATH_KERN_WARN
 513                        "unexpected virtual io event subtype %d from partition %d\n",
 514                        event->xSubtype, remoteLp);
 515                 /* No handler.  Ack if necessary */
 516                 if ((event->xFlags.xFunction == HvLpEvent_Function_Int) &&
 517                     (event->xFlags.xAckInd == HvLpEvent_AckInd_DoAck)) {
 518                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
 519                         HvCallEvent_ackLpEvent(event);
 520                 }
 521                 return;
 522         }
 523
 524         /* This innocuous little line is where all the real work happens */
 525         (*vio_handler[subtype])(event);
 526 }
 527
 528 static void viopath_donealloc(void *parm, int number)
 529 {
 530         struct doneAllocParms_t *parmsp = (struct doneAllocParms_t *)parm;
 531
 532         parmsp->number = number;
 533         if (parmsp->used_wait_atomic)
 534                 atomic_set(parmsp->wait_atomic, 0);
 535         else
 536                 up(parmsp->sem);
 537 }
 538
 539 static int allocateEvents(HvLpIndex remoteLp, int numEvents)
 540 {
 541         struct doneAllocParms_t parms;
 542         DECLARE_MUTEX_LOCKED(Semaphore);
 543         atomic_t wait_atomic;
 544
 545         if (in_atomic()) {
 546                 parms.used_wait_atomic = 1;
 547                 atomic_set(&wait_atomic, 1);
 548                 parms.wait_atomic = &wait_atomic;
 549         } else {
 550                 parms.used_wait_atomic = 0;
 551                 parms.sem = &Semaphore;
 552         }
 553         mf_allocateLpEvents(remoteLp, HvLpEvent_Type_VirtualIo, 250,    /* It would be nice to put a real number here! */
 554                             numEvents, &viopath_donealloc, &parms);
 555         if (in_atomic()) {
 556                 while (atomic_read(&wait_atomic))
 557                         mb();
 558         } else
 559                 down(&Semaphore);
 560         return parms.number;
 561 }
 562
 563 int viopath_open(HvLpIndex remoteLp, int subtype, int numReq)
 564 {
 565         int i;
 566         unsigned long flags;
 567         int tempNumAllocated;
 568
 569         if ((remoteLp >= HvMaxArchitectedLps) || (remoteLp == HvLpIndexInvalid))
 570                 return -EINVAL;
 571
 572         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 573         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 574                 return -EINVAL;
 575
 576         spin_lock_irqsave(&statuslock, flags);
 577
 578         if (!event_buffer_initialised) {
 579                 for (i = 0; i < VIO_MAX_SUBTYPES; i++)
 580                         atomic_set(&event_buffer_available[i], 1);
 581                 event_buffer_initialised = 1;
 582         }
 583
 584         viopathStatus[remoteLp].users[subtype]++;
 585
 586         if (!viopathStatus[remoteLp].isOpen) {
 587                 viopathStatus[remoteLp].isOpen = 1;
 588                 HvCallEvent_openLpEventPath(remoteLp, HvLpEvent_Type_VirtualIo);
 589
 590                 /*
 591                  * Don't hold the spinlock during an operation that
 592                  * can sleep.
 593                  */
 594                 spin_unlock_irqrestore(&statuslock, flags);
 595                 tempNumAllocated = allocateEvents(remoteLp, 1);
 596                 spin_lock_irqsave(&statuslock, flags);
 597
 598                 viopathStatus[remoteLp].numberAllocated += tempNumAllocated;
 599
 600                 if (viopathStatus[remoteLp].numberAllocated == 0) {
 601                         HvCallEvent_closeLpEventPath(remoteLp,
 602                                         HvLpEvent_Type_VirtualIo);
 603
 604                         spin_unlock_irqrestore(&statuslock, flags);
 605                         return -ENOMEM;
 606                 }
 607
 608                 viopathStatus[remoteLp].mSourceInst =
 609                         HvCallEvent_getSourceLpInstanceId(remoteLp,
 610                                         HvLpEvent_Type_VirtualIo);
 611                 viopathStatus[remoteLp].mTargetInst =
 612                         HvCallEvent_getTargetLpInstanceId(remoteLp,
 613                                         HvLpEvent_Type_VirtualIo);
 614                 HvLpEvent_registerHandler(HvLpEvent_Type_VirtualIo,
 615                                           &vio_handleEvent);
 616                 sendMonMsg(remoteLp);
 617                 printk(VIOPATH_KERN_INFO "opening connection to partition %d, "
 618                                 "setting sinst %d, tinst %d\n",
 619                                 remoteLp, viopathStatus[remoteLp].mSourceInst,
 620                                 viopathStatus[remoteLp].mTargetInst);
 621         }
 622
 623         spin_unlock_irqrestore(&statuslock, flags);
 624         tempNumAllocated = allocateEvents(remoteLp, numReq);
 625         spin_lock_irqsave(&statuslock, flags);
 626         viopathStatus[remoteLp].numberAllocated += tempNumAllocated;
 627         spin_unlock_irqrestore(&statuslock, flags);
 628
 629         return 0;
 630 }
 631 EXPORT_SYMBOL(viopath_open);
 632
 633 int viopath_close(HvLpIndex remoteLp, int subtype, int numReq)
 634 {
 635         unsigned long flags;
 636         int i;
 637         int numOpen;
 638         struct doneAllocParms_t doneAllocParms;
 639         DECLARE_MUTEX_LOCKED(Semaphore);
 640
 641         if ((remoteLp >= HvMaxArchitectedLps) || (remoteLp == HvLpIndexInvalid))
 642                 return -EINVAL;
 643
 644         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 645         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 646                 return -EINVAL;
 647
 648         spin_lock_irqsave(&statuslock, flags);
 649         /*
 650          * If the viopath_close somehow gets called before a
 651          * viopath_open it could decrement to -1 which is a non
 652          * recoverable state so we'll prevent this from
 653          * happening.
 654          */
 655         if (viopathStatus[remoteLp].users[subtype] > 0)
 656                 viopathStatus[remoteLp].users[subtype]--;
 657
 658         spin_unlock_irqrestore(&statuslock, flags);
 659
 660         doneAllocParms.used_wait_atomic = 0;
 661         doneAllocParms.sem = &Semaphore;
 662         mf_deallocateLpEvents(remoteLp, HvLpEvent_Type_VirtualIo,
 663                               numReq, &viopath_donealloc, &doneAllocParms);
 664         down(&Semaphore);
 665
 666         spin_lock_irqsave(&statuslock, flags);
 667         for (i = 0, numOpen = 0; i < VIO_MAX_SUBTYPES; i++)
 668                 numOpen += viopathStatus[remoteLp].users[i];
 669
 670         if ((viopathStatus[remoteLp].isOpen) && (numOpen == 0)) {
 671                 printk(VIOPATH_KERN_INFO "closing connection to partition %d",
 672                                 remoteLp);
 673
 674                 HvCallEvent_closeLpEventPath(remoteLp,
 675                                              HvLpEvent_Type_VirtualIo);
 676                 viopathStatus[remoteLp].isOpen = 0;
 677                 viopathStatus[remoteLp].isActive = 0;
 678
 679                 for (i = 0; i < VIO_MAX_SUBTYPES; i++)
 680                         atomic_set(&event_buffer_available[i], 0);
 681                 event_buffer_initialised = 0;
 682         }
 683         spin_unlock_irqrestore(&statuslock, flags);
 684         return 0;
 685 }
 686 EXPORT_SYMBOL(viopath_close);
 687
 688 void *vio_get_event_buffer(int subtype)
 689 {
 690         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 691         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 692                 return NULL;
 693
 694         if (atomic_dec_if_positive(&event_buffer_available[subtype]) == 0)
 695                 return &event_buffer[subtype * 256];
 696         else
 697                 return NULL;
 698 }
 699 EXPORT_SYMBOL(vio_get_event_buffer);
 700
 701 void vio_free_event_buffer(int subtype, void *buffer)
 702 {
 703         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 704         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES)) {
 705                 printk(VIOPATH_KERN_WARN
 706                        "unexpected subtype %d freeing event buffer\n", subtype);
 707                 return;
 708         }
 709
 710         if (atomic_read(&event_buffer_available[subtype]) != 0) {
 711                 printk(VIOPATH_KERN_WARN
 712                        "freeing unallocated event buffer, subtype %d\n",
 713                        subtype);
 714                 return;
 715         }
 716
 717         if (buffer != &event_buffer[subtype * 256]) {
 718                 printk(VIOPATH_KERN_WARN
 719                        "freeing invalid event buffer, subtype %d\n", subtype);
 720         }
 721
 722         atomic_set(&event_buffer_available[subtype], 1);
 723 }
 724 EXPORT_SYMBOL(vio_free_event_buffer);
 725
 726 static const struct vio_error_entry vio_no_error =
 727     { 0, 0, "Non-VIO Error" };
 728 static const struct vio_error_entry vio_unknown_error =
 729     { 0, EIO, "Unknown Error" };
 730
 731 static const struct vio_error_entry vio_default_errors[] = {
 732         {0x0001, EIO, "No Connection"},
 733         {0x0002, EIO, "No Receiver"},
 734         {0x0003, EIO, "No Buffer Available"},
 735         {0x0004, EBADRQC, "Invalid Message Type"},
 736         {0x0000, 0, NULL},
 737 };
 738
 739 const struct vio_error_entry *vio_lookup_rc(
 740                 const struct vio_error_entry *local_table, u16 rc)
 741 {
 742         const struct vio_error_entry *cur;
 743
 744         if (!rc)
 745                 return &vio_no_error;
 746         if (local_table)
 747                 for (cur = local_table; cur->rc; ++cur)
 748                         if (cur->rc == rc)
 749                                 return cur;
 750         for (cur = vio_default_errors; cur->rc; ++cur)
 751                 if (cur->rc == rc)
 752                         return cur;
 753         return &vio_unknown_error;
 754 }
 755 EXPORT_SYMBOL(vio_lookup_rc);