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   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 #include <linux/smp_lock.h>
  41 #include <linux/interrupt.h>
  42
  43 #include <asm/system.h>
  44 #include <asm/uaccess.h>
  45 #include <asm/iSeries/HvTypes.h>
  46 #include <asm/iSeries/LparData.h>
  47 #include <asm/iSeries/HvLpEvent.h>
  48 #include <asm/iSeries/HvLpConfig.h>
  49 #include <asm/iSeries/HvCallCfg.h>
  50 #include <asm/iSeries/mf.h>
  51 #include <asm/iSeries/iSeries_proc.h>
  52 #include <asm/iSeries/vio.h>
  53
  54 /* Status of the path to each other partition in the system.
  55  * This is overkill, since we will only ever establish connections
  56  * to our hosting partition and the primary partition on the system.
  57  * But this allows for other support in the future.
  58  */
  59 static struct viopathStatus {
  60         int isOpen;             /* Did we open the path?            */
  61         int isActive;           /* Do we have a mon msg outstanding */
  62         int users[VIO_MAX_SUBTYPES];
  63         HvLpInstanceId mSourceInst;
  64         HvLpInstanceId mTargetInst;
  65         int numberAllocated;
  66 } viopathStatus[HVMAXARCHITECTEDLPS];
  67
  68 static DEFINE_SPINLOCK(statuslock);
  69
  70 /*
  71  * For each kind of event we allocate a buffer that is
  72  * guaranteed not to cross a page boundary
  73  */
  74 static unsigned char event_buffer[VIO_MAX_SUBTYPES * 256] __page_aligned;
  75 static atomic_t event_buffer_available[VIO_MAX_SUBTYPES];
  76 static int event_buffer_initialised;
  77
  78 static void handleMonitorEvent(struct HvLpEvent *event);
  79
  80 /*
  81  * We use this structure to handle asynchronous responses.  The caller
  82  * blocks on the semaphore and the handler posts the semaphore.  However,
  83  * if system_state is not SYSTEM_RUNNING, then wait_atomic is used ...
  84  */
  85 struct alloc_parms {
  86         struct semaphore sem;
  87         int number;
  88         atomic_t wait_atomic;
  89         int used_wait_atomic;
  90 };
  91
  92 /* Put a sequence number in each mon msg.  The value is not
  93  * important.  Start at something other than 0 just for
  94  * readability.  wrapping this is ok.
  95  */
  96 static u8 viomonseq = 22;
  97
  98 /* Our hosting logical partition.  We get this at startup
  99  * time, and different modules access this variable directly.
 100  */
 101 HvLpIndex viopath_hostLp = HvLpIndexInvalid;
 102 EXPORT_SYMBOL(viopath_hostLp);
 103 HvLpIndex viopath_ourLp = HvLpIndexInvalid;
 104 EXPORT_SYMBOL(viopath_ourLp);
 105
 106 /* For each kind of incoming event we set a pointer to a
 107  * routine to call.
 108  */
 109 static vio_event_handler_t *vio_handler[VIO_MAX_SUBTYPES];
 110
 111 #define VIOPATH_KERN_WARN       KERN_WARNING "viopath: "
 112 #define VIOPATH_KERN_INFO       KERN_INFO "viopath: "
 113
 114 static int proc_viopath_show(struct seq_file *m, void *v)
 115 {
 116         char *buf;
 117         u16 vlanMap;
 118         dma_addr_t handle;
 119         HvLpEvent_Rc hvrc;
 120         DECLARE_MUTEX_LOCKED(Semaphore);
 121
 122         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 123         if (!buf)
 124                 return 0;
 125         memset(buf, 0, PAGE_SIZE);
 126
 127         handle = dma_map_single(iSeries_vio_dev, buf, PAGE_SIZE,
 128                                 DMA_FROM_DEVICE);
 129
 130         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
 131                         HvLpEvent_Type_VirtualIo,
 132                         viomajorsubtype_config | vioconfigget,
 133                         HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
 134                         viopath_sourceinst(viopath_hostLp),
 135                         viopath_targetinst(viopath_hostLp),
 136                         (u64)(unsigned long)&Semaphore, VIOVERSION << 16,
 137                         ((u64)handle) << 32, PAGE_SIZE, 0, 0);
 138
 139         if (hvrc != HvLpEvent_Rc_Good)
 140                 printk(VIOPATH_KERN_WARN "hv error on op %d\n", (int)hvrc);
 141
 142         down(&Semaphore);
 143
 144         vlanMap = HvLpConfig_getVirtualLanIndexMap();
 145
 146         buf[PAGE_SIZE-1] = '\0';
 147         seq_printf(m, "%s", buf);
 148         seq_printf(m, "AVAILABLE_VETH=%x\n", vlanMap);
 149         seq_printf(m, "SRLNBR=%c%c%c%c%c%c%c\n",
 150                    e2a(xItExtVpdPanel.mfgID[2]),
 151                    e2a(xItExtVpdPanel.mfgID[3]),
 152                    e2a(xItExtVpdPanel.systemSerial[1]),
 153                    e2a(xItExtVpdPanel.systemSerial[2]),
 154                    e2a(xItExtVpdPanel.systemSerial[3]),
 155                    e2a(xItExtVpdPanel.systemSerial[4]),
 156                    e2a(xItExtVpdPanel.systemSerial[5]));
 157
 158         dma_unmap_single(iSeries_vio_dev, handle, PAGE_SIZE, DMA_FROM_DEVICE);
 159         kfree(buf);
 160
 161         return 0;
 162 }
 163
 164 static int proc_viopath_open(struct inode *inode, struct file *file)
 165 {
 166         return single_open(file, proc_viopath_show, NULL);
 167 }
 168
 169 static struct file_operations proc_viopath_operations = {
 170         .open           = proc_viopath_open,
 171         .read           = seq_read,
 172         .llseek         = seq_lseek,
 173         .release        = single_release,
 174 };
 175
 176 static int __init vio_proc_init(void)
 177 {
 178         struct proc_dir_entry *e;
 179
 180         e = create_proc_entry("iSeries/config", 0, NULL);
 181         if (e)
 182                 e->proc_fops = &proc_viopath_operations;
 183
 184         return 0;
 185 }
 186 __initcall(vio_proc_init);
 187
 188 /* See if a given LP is active.  Allow for invalid lps to be passed in
 189  * and just return invalid
 190  */
 191 int viopath_isactive(HvLpIndex lp)
 192 {
 193         if (lp == HvLpIndexInvalid)
 194                 return 0;
 195         if (lp < HVMAXARCHITECTEDLPS)
 196                 return viopathStatus[lp].isActive;
 197         else
 198                 return 0;
 199 }
 200 EXPORT_SYMBOL(viopath_isactive);
 201
 202 /*
 203  * We cache the source and target instance ids for each
 204  * partition.
 205  */
 206 HvLpInstanceId viopath_sourceinst(HvLpIndex lp)
 207 {
 208         return viopathStatus[lp].mSourceInst;
 209 }
 210 EXPORT_SYMBOL(viopath_sourceinst);
 211
 212 HvLpInstanceId viopath_targetinst(HvLpIndex lp)
 213 {
 214         return viopathStatus[lp].mTargetInst;
 215 }
 216 EXPORT_SYMBOL(viopath_targetinst);
 217
 218 /*
 219  * Send a monitor message.  This is a message with the acknowledge
 220  * bit on that the other side will NOT explicitly acknowledge.  When
 221  * the other side goes down, the hypervisor will acknowledge any
 222  * outstanding messages....so we will know when the other side dies.
 223  */
 224 static void sendMonMsg(HvLpIndex remoteLp)
 225 {
 226         HvLpEvent_Rc hvrc;
 227
 228         viopathStatus[remoteLp].mSourceInst =
 229                 HvCallEvent_getSourceLpInstanceId(remoteLp,
 230                                 HvLpEvent_Type_VirtualIo);
 231         viopathStatus[remoteLp].mTargetInst =
 232                 HvCallEvent_getTargetLpInstanceId(remoteLp,
 233                                 HvLpEvent_Type_VirtualIo);
 234
 235         /*
 236          * Deliberately ignore the return code here.  if we call this
 237          * more than once, we don't care.
 238          */
 239         vio_setHandler(viomajorsubtype_monitor, handleMonitorEvent);
 240
 241         hvrc = HvCallEvent_signalLpEventFast(remoteLp, HvLpEvent_Type_VirtualIo,
 242                         viomajorsubtype_monitor, HvLpEvent_AckInd_DoAck,
 243                         HvLpEvent_AckType_DeferredAck,
 244                         viopathStatus[remoteLp].mSourceInst,
 245                         viopathStatus[remoteLp].mTargetInst,
 246                         viomonseq++, 0, 0, 0, 0, 0);
 247
 248         if (hvrc == HvLpEvent_Rc_Good)
 249                 viopathStatus[remoteLp].isActive = 1;
 250         else {
 251                 printk(VIOPATH_KERN_WARN "could not connect to partition %d\n",
 252                                 remoteLp);
 253                 viopathStatus[remoteLp].isActive = 0;
 254         }
 255 }
 256
 257 static void handleMonitorEvent(struct HvLpEvent *event)
 258 {
 259         HvLpIndex remoteLp;
 260         int i;
 261
 262         /*
 263          * This handler is _also_ called as part of the loop
 264          * at the end of this routine, so it must be able to
 265          * ignore NULL events...
 266          */
 267         if (!event)
 268                 return;
 269
 270         /*
 271          * First see if this is just a normal monitor message from the
 272          * other partition
 273          */
 274         if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
 275                 remoteLp = event->xSourceLp;
 276                 if (!viopathStatus[remoteLp].isActive)
 277                         sendMonMsg(remoteLp);
 278                 return;
 279         }
 280
 281         /*
 282          * This path is for an acknowledgement; the other partition
 283          * died
 284          */
 285         remoteLp = event->xTargetLp;
 286         if ((event->xSourceInstanceId != viopathStatus[remoteLp].mSourceInst) ||
 287             (event->xTargetInstanceId != viopathStatus[remoteLp].mTargetInst)) {
 288                 printk(VIOPATH_KERN_WARN "ignoring ack....mismatched instances\n");
 289                 return;
 290         }
 291
 292         printk(VIOPATH_KERN_WARN "partition %d ended\n", remoteLp);
 293
 294         viopathStatus[remoteLp].isActive = 0;
 295
 296         /*
 297          * For each active handler, pass them a NULL
 298          * message to indicate that the other partition
 299          * died
 300          */
 301         for (i = 0; i < VIO_MAX_SUBTYPES; i++) {
 302                 if (vio_handler[i] != NULL)
 303                         (*vio_handler[i])(NULL);
 304         }
 305 }
 306
 307 int vio_setHandler(int subtype, vio_event_handler_t *beh)
 308 {
 309         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 310         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 311                 return -EINVAL;
 312         if (vio_handler[subtype] != NULL)
 313                 return -EBUSY;
 314         vio_handler[subtype] = beh;
 315         return 0;
 316 }
 317 EXPORT_SYMBOL(vio_setHandler);
 318
 319 int vio_clearHandler(int subtype)
 320 {
 321         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 322         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 323                 return -EINVAL;
 324         if (vio_handler[subtype] == NULL)
 325                 return -EAGAIN;
 326         vio_handler[subtype] = NULL;
 327         return 0;
 328 }
 329 EXPORT_SYMBOL(vio_clearHandler);
 330
 331 static void handleConfig(struct HvLpEvent *event)
 332 {
 333         if (!event)
 334                 return;
 335         if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
 336                 printk(VIOPATH_KERN_WARN
 337                        "unexpected config request from partition %d",
 338                        event->xSourceLp);
 339
 340                 if ((event->xFlags.xFunction == HvLpEvent_Function_Int) &&
 341                     (event->xFlags.xAckInd == HvLpEvent_AckInd_DoAck)) {
 342                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
 343                         HvCallEvent_ackLpEvent(event);
 344                 }
 345                 return;
 346         }
 347
 348         up((struct semaphore *)event->xCorrelationToken);
 349 }
 350
 351 /*
 352  * Initialization of the hosting partition
 353  */
 354 void vio_set_hostlp(void)
 355 {
 356         /*
 357          * If this has already been set then we DON'T want to either change
 358          * it or re-register the proc file system
 359          */
 360         if (viopath_hostLp != HvLpIndexInvalid)
 361                 return;
 362
 363         /*
 364          * Figure out our hosting partition.  This isn't allowed to change
 365          * while we're active
 366          */
 367         viopath_ourLp = HvLpConfig_getLpIndex();
 368         viopath_hostLp = HvCallCfg_getHostingLpIndex(viopath_ourLp);
 369
 370         if (viopath_hostLp != HvLpIndexInvalid)
 371                 vio_setHandler(viomajorsubtype_config, handleConfig);
 372 }
 373 EXPORT_SYMBOL(vio_set_hostlp);
 374
 375 static void vio_handleEvent(struct HvLpEvent *event, struct pt_regs *regs)
 376 {
 377         HvLpIndex remoteLp;
 378         int subtype = (event->xSubtype & VIOMAJOR_SUBTYPE_MASK)
 379                 >> VIOMAJOR_SUBTYPE_SHIFT;
 380
 381         if (event->xFlags.xFunction == HvLpEvent_Function_Int) {
 382                 remoteLp = event->xSourceLp;
 383                 /*
 384                  * The isActive is checked because if the hosting partition
 385                  * went down and came back up it would not be active but it
 386                  * would have different source and target instances, in which
 387                  * case we'd want to reset them.  This case really protects
 388                  * against an unauthorized active partition sending interrupts
 389                  * or acks to this linux partition.
 390                  */
 391                 if (viopathStatus[remoteLp].isActive
 392                     && (event->xSourceInstanceId !=
 393                         viopathStatus[remoteLp].mTargetInst)) {
 394                         printk(VIOPATH_KERN_WARN
 395                                "message from invalid partition. "
 396                                "int msg rcvd, source inst (%d) doesnt match (%d)\n",
 397                                viopathStatus[remoteLp].mTargetInst,
 398                                event->xSourceInstanceId);
 399                         return;
 400                 }
 401
 402                 if (viopathStatus[remoteLp].isActive
 403                     && (event->xTargetInstanceId !=
 404                         viopathStatus[remoteLp].mSourceInst)) {
 405                         printk(VIOPATH_KERN_WARN
 406                                "message from invalid partition. "
 407                                "int msg rcvd, target inst (%d) doesnt match (%d)\n",
 408                                viopathStatus[remoteLp].mSourceInst,
 409                                event->xTargetInstanceId);
 410                         return;
 411                 }
 412         } else {
 413                 remoteLp = event->xTargetLp;
 414                 if (event->xSourceInstanceId !=
 415                     viopathStatus[remoteLp].mSourceInst) {
 416                         printk(VIOPATH_KERN_WARN
 417                                "message from invalid partition. "
 418                                "ack msg rcvd, source inst (%d) doesnt match (%d)\n",
 419                                viopathStatus[remoteLp].mSourceInst,
 420                                event->xSourceInstanceId);
 421                         return;
 422                 }
 423
 424                 if (event->xTargetInstanceId !=
 425                     viopathStatus[remoteLp].mTargetInst) {
 426                         printk(VIOPATH_KERN_WARN
 427                                "message from invalid partition. "
 428                                "viopath: ack msg rcvd, target inst (%d) doesnt match (%d)\n",
 429                                viopathStatus[remoteLp].mTargetInst,
 430                                event->xTargetInstanceId);
 431                         return;
 432                 }
 433         }
 434
 435         if (vio_handler[subtype] == NULL) {
 436                 printk(VIOPATH_KERN_WARN
 437                        "unexpected virtual io event subtype %d from partition %d\n",
 438                        event->xSubtype, remoteLp);
 439                 /* No handler.  Ack if necessary */
 440                 if ((event->xFlags.xFunction == HvLpEvent_Function_Int) &&
 441                     (event->xFlags.xAckInd == HvLpEvent_AckInd_DoAck)) {
 442                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
 443                         HvCallEvent_ackLpEvent(event);
 444                 }
 445                 return;
 446         }
 447
 448         /* This innocuous little line is where all the real work happens */
 449         (*vio_handler[subtype])(event);
 450 }
 451
 452 static void viopath_donealloc(void *parm, int number)
 453 {
 454         struct alloc_parms *parmsp = parm;
 455
 456         parmsp->number = number;
 457         if (parmsp->used_wait_atomic)
 458                 atomic_set(&parmsp->wait_atomic, 0);
 459         else
 460                 up(&parmsp->sem);
 461 }
 462
 463 static int allocateEvents(HvLpIndex remoteLp, int numEvents)
 464 {
 465         struct alloc_parms parms;
 466
 467         if (system_state != SYSTEM_RUNNING) {
 468                 parms.used_wait_atomic = 1;
 469                 atomic_set(&parms.wait_atomic, 1);
 470         } else {
 471                 parms.used_wait_atomic = 0;
 472                 init_MUTEX_LOCKED(&parms.sem);
 473         }
 474         mf_allocate_lp_events(remoteLp, HvLpEvent_Type_VirtualIo, 250,  /* It would be nice to put a real number here! */
 475                             numEvents, &viopath_donealloc, &parms);
 476         if (system_state != SYSTEM_RUNNING) {
 477                 while (atomic_read(&parms.wait_atomic))
 478                         mb();
 479         } else
 480                 down(&parms.sem);
 481         return parms.number;
 482 }
 483
 484 int viopath_open(HvLpIndex remoteLp, int subtype, int numReq)
 485 {
 486         int i;
 487         unsigned long flags;
 488         int tempNumAllocated;
 489
 490         if ((remoteLp >= HvMaxArchitectedLps) || (remoteLp == HvLpIndexInvalid))
 491                 return -EINVAL;
 492
 493         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 494         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 495                 return -EINVAL;
 496
 497         spin_lock_irqsave(&statuslock, flags);
 498
 499         if (!event_buffer_initialised) {
 500                 for (i = 0; i < VIO_MAX_SUBTYPES; i++)
 501                         atomic_set(&event_buffer_available[i], 1);
 502                 event_buffer_initialised = 1;
 503         }
 504
 505         viopathStatus[remoteLp].users[subtype]++;
 506
 507         if (!viopathStatus[remoteLp].isOpen) {
 508                 viopathStatus[remoteLp].isOpen = 1;
 509                 HvCallEvent_openLpEventPath(remoteLp, HvLpEvent_Type_VirtualIo);
 510
 511                 /*
 512                  * Don't hold the spinlock during an operation that
 513                  * can sleep.
 514                  */
 515                 spin_unlock_irqrestore(&statuslock, flags);
 516                 tempNumAllocated = allocateEvents(remoteLp, 1);
 517                 spin_lock_irqsave(&statuslock, flags);
 518
 519                 viopathStatus[remoteLp].numberAllocated += tempNumAllocated;
 520
 521                 if (viopathStatus[remoteLp].numberAllocated == 0) {
 522                         HvCallEvent_closeLpEventPath(remoteLp,
 523                                         HvLpEvent_Type_VirtualIo);
 524
 525                         spin_unlock_irqrestore(&statuslock, flags);
 526                         return -ENOMEM;
 527                 }
 528
 529                 viopathStatus[remoteLp].mSourceInst =
 530                         HvCallEvent_getSourceLpInstanceId(remoteLp,
 531                                         HvLpEvent_Type_VirtualIo);
 532                 viopathStatus[remoteLp].mTargetInst =
 533                         HvCallEvent_getTargetLpInstanceId(remoteLp,
 534                                         HvLpEvent_Type_VirtualIo);
 535                 HvLpEvent_registerHandler(HvLpEvent_Type_VirtualIo,
 536                                           &vio_handleEvent);
 537                 sendMonMsg(remoteLp);
 538                 printk(VIOPATH_KERN_INFO "opening connection to partition %d, "
 539                                 "setting sinst %d, tinst %d\n",
 540                                 remoteLp, viopathStatus[remoteLp].mSourceInst,
 541                                 viopathStatus[remoteLp].mTargetInst);
 542         }
 543
 544         spin_unlock_irqrestore(&statuslock, flags);
 545         tempNumAllocated = allocateEvents(remoteLp, numReq);
 546         spin_lock_irqsave(&statuslock, flags);
 547         viopathStatus[remoteLp].numberAllocated += tempNumAllocated;
 548         spin_unlock_irqrestore(&statuslock, flags);
 549
 550         return 0;
 551 }
 552 EXPORT_SYMBOL(viopath_open);
 553
 554 int viopath_close(HvLpIndex remoteLp, int subtype, int numReq)
 555 {
 556         unsigned long flags;
 557         int i;
 558         int numOpen;
 559         struct alloc_parms parms;
 560
 561         if ((remoteLp >= HvMaxArchitectedLps) || (remoteLp == HvLpIndexInvalid))
 562                 return -EINVAL;
 563
 564         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 565         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 566                 return -EINVAL;
 567
 568         spin_lock_irqsave(&statuslock, flags);
 569         /*
 570          * If the viopath_close somehow gets called before a
 571          * viopath_open it could decrement to -1 which is a non
 572          * recoverable state so we'll prevent this from
 573          * happening.
 574          */
 575         if (viopathStatus[remoteLp].users[subtype] > 0)
 576                 viopathStatus[remoteLp].users[subtype]--;
 577
 578         spin_unlock_irqrestore(&statuslock, flags);
 579
 580         parms.used_wait_atomic = 0;
 581         init_MUTEX_LOCKED(&parms.sem);
 582         mf_deallocate_lp_events(remoteLp, HvLpEvent_Type_VirtualIo,
 583                               numReq, &viopath_donealloc, &parms);
 584         down(&parms.sem);
 585
 586         spin_lock_irqsave(&statuslock, flags);
 587         for (i = 0, numOpen = 0; i < VIO_MAX_SUBTYPES; i++)
 588                 numOpen += viopathStatus[remoteLp].users[i];
 589
 590         if ((viopathStatus[remoteLp].isOpen) && (numOpen == 0)) {
 591                 printk(VIOPATH_KERN_INFO "closing connection to partition %d",
 592                                 remoteLp);
 593
 594                 HvCallEvent_closeLpEventPath(remoteLp,
 595                                              HvLpEvent_Type_VirtualIo);
 596                 viopathStatus[remoteLp].isOpen = 0;
 597                 viopathStatus[remoteLp].isActive = 0;
 598
 599                 for (i = 0; i < VIO_MAX_SUBTYPES; i++)
 600                         atomic_set(&event_buffer_available[i], 0);
 601                 event_buffer_initialised = 0;
 602         }
 603         spin_unlock_irqrestore(&statuslock, flags);
 604         return 0;
 605 }
 606 EXPORT_SYMBOL(viopath_close);
 607
 608 void *vio_get_event_buffer(int subtype)
 609 {
 610         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 611         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
 612                 return NULL;
 613
 614         if (atomic_dec_if_positive(&event_buffer_available[subtype]) == 0)
 615                 return &event_buffer[subtype * 256];
 616         else
 617                 return NULL;
 618 }
 619 EXPORT_SYMBOL(vio_get_event_buffer);
 620
 621 void vio_free_event_buffer(int subtype, void *buffer)
 622 {
 623         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
 624         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES)) {
 625                 printk(VIOPATH_KERN_WARN
 626                        "unexpected subtype %d freeing event buffer\n", subtype);
 627                 return;
 628         }
 629
 630         if (atomic_read(&event_buffer_available[subtype]) != 0) {
 631                 printk(VIOPATH_KERN_WARN
 632                        "freeing unallocated event buffer, subtype %d\n",
 633                        subtype);
 634                 return;
 635         }
 636
 637         if (buffer != &event_buffer[subtype * 256]) {
 638                 printk(VIOPATH_KERN_WARN
 639                        "freeing invalid event buffer, subtype %d\n", subtype);
 640         }
 641
 642         atomic_set(&event_buffer_available[subtype], 1);
 643 }
 644 EXPORT_SYMBOL(vio_free_event_buffer);
 645
 646 static const struct vio_error_entry vio_no_error =
 647     { 0, 0, "Non-VIO Error" };
 648 static const struct vio_error_entry vio_unknown_error =
 649     { 0, EIO, "Unknown Error" };
 650
 651 static const struct vio_error_entry vio_default_errors[] = {
 652         {0x0001, EIO, "No Connection"},
 653         {0x0002, EIO, "No Receiver"},
 654         {0x0003, EIO, "No Buffer Available"},
 655         {0x0004, EBADRQC, "Invalid Message Type"},
 656         {0x0000, 0, NULL},
 657 };
 658
 659 const struct vio_error_entry *vio_lookup_rc(
 660                 const struct vio_error_entry *local_table, u16 rc)
 661 {
 662         const struct vio_error_entry *cur;
 663
 664         if (!rc)
 665                 return &vio_no_error;
 666         if (local_table)
 667                 for (cur = local_table; cur->rc; ++cur)
 668                         if (cur->rc == rc)
 669                                 return cur;
 670         for (cur = vio_default_errors; cur->rc; ++cur)
 671                 if (cur->rc == rc)
 672                         return cur;
 673         return &vio_unknown_error;
 674 }
 675 EXPORT_SYMBOL(vio_lookup_rc);