Merge branch 'pdc' into release
[linux-2.6.git] / arch / powerpc / platforms / iseries / viopath.c
1 /* -*- linux-c -*-
2  *
3  *  iSeries Virtual I/O Message Path code
4  *
5  *  Authors: Dave Boutcher <boutcher@us.ibm.com>
6  *           Ryan Arnold <ryanarn@us.ibm.com>
7  *           Colin Devilbiss <devilbis@us.ibm.com>
8  *
9  * (C) Copyright 2000-2005 IBM Corporation
10  *
11  * This code is used by the iSeries virtual disk, cd,
12  * tape, and console to communicate with OS/400 in another
13  * partition.
14  *
15  * This program is free software;  you can redistribute it and/or
16  * modify it under the terms of the GNU General Public License as
17  * published by the Free Software Foundation; either version 2 of the
18  * License, or (at your option) anyu later version.
19  *
20  * This program is distributed in the hope that it will be useful, but
21  * WITHOUT ANY WARRANTY; without even the implied warranty of
22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
23  * General Public License for more details.
24  *
25  * You should have received a copy of the GNU General Public License
26  * along with this program; if not, write to the Free Software Foundation,
27  * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28  *
29  */
30 #include <linux/module.h>
31 #include <linux/kernel.h>
32 #include <linux/errno.h>
33 #include <linux/vmalloc.h>
34 #include <linux/string.h>
35 #include <linux/proc_fs.h>
36 #include <linux/dma-mapping.h>
37 #include <linux/wait.h>
38 #include <linux/seq_file.h>
39 #include <linux/interrupt.h>
40 #include <linux/completion.h>
41
42 #include <asm/system.h>
43 #include <asm/uaccess.h>
44 #include <asm/prom.h>
45 #include <asm/firmware.h>
46 #include <asm/iseries/hv_types.h>
47 #include <asm/iseries/hv_lp_event.h>
48 #include <asm/iseries/hv_lp_config.h>
49 #include <asm/iseries/mf.h>
50 #include <asm/iseries/vio.h>
51
52 /* Status of the path to each other partition in the system.
53  * This is overkill, since we will only ever establish connections
54  * to our hosting partition and the primary partition on the system.
55  * But this allows for other support in the future.
56  */
57 static struct viopathStatus {
58         int isOpen;             /* Did we open the path?            */
59         int isActive;           /* Do we have a mon msg outstanding */
60         int users[VIO_MAX_SUBTYPES];
61         HvLpInstanceId mSourceInst;
62         HvLpInstanceId mTargetInst;
63         int numberAllocated;
64 } viopathStatus[HVMAXARCHITECTEDLPS];
65
66 static DEFINE_SPINLOCK(statuslock);
67
68 /*
69  * For each kind of event we allocate a buffer that is
70  * guaranteed not to cross a page boundary
71  */
72 static unsigned char event_buffer[VIO_MAX_SUBTYPES * 256]
73         __attribute__((__aligned__(4096)));
74 static atomic_t event_buffer_available[VIO_MAX_SUBTYPES];
75 static int event_buffer_initialised;
76
77 static void handleMonitorEvent(struct HvLpEvent *event);
78
79 /*
80  * We use this structure to handle asynchronous responses.  The caller
81  * blocks on the semaphore and the handler posts the semaphore.  However,
82  * if system_state is not SYSTEM_RUNNING, then wait_atomic is used ...
83  */
84 struct alloc_parms {
85         struct completion done;
86         int number;
87         atomic_t wait_atomic;
88         int used_wait_atomic;
89 };
90
91 /* Put a sequence number in each mon msg.  The value is not
92  * important.  Start at something other than 0 just for
93  * readability.  wrapping this is ok.
94  */
95 static u8 viomonseq = 22;
96
97 /* Our hosting logical partition.  We get this at startup
98  * time, and different modules access this variable directly.
99  */
100 HvLpIndex viopath_hostLp = HvLpIndexInvalid;
101 EXPORT_SYMBOL(viopath_hostLp);
102 HvLpIndex viopath_ourLp = HvLpIndexInvalid;
103 EXPORT_SYMBOL(viopath_ourLp);
104
105 /* For each kind of incoming event we set a pointer to a
106  * routine to call.
107  */
108 static vio_event_handler_t *vio_handler[VIO_MAX_SUBTYPES];
109
110 #define VIOPATH_KERN_WARN       KERN_WARNING "viopath: "
111 #define VIOPATH_KERN_INFO       KERN_INFO "viopath: "
112
113 static int proc_viopath_show(struct seq_file *m, void *v)
114 {
115         char *buf;
116         u16 vlanMap;
117         dma_addr_t handle;
118         HvLpEvent_Rc hvrc;
119         DECLARE_COMPLETION_ONSTACK(done);
120         struct device_node *node;
121         const char *sysid;
122
123         buf = kzalloc(HW_PAGE_SIZE, GFP_KERNEL);
124         if (!buf)
125                 return 0;
126
127         handle = iseries_hv_map(buf, HW_PAGE_SIZE, DMA_FROM_DEVICE);
128
129         hvrc = HvCallEvent_signalLpEventFast(viopath_hostLp,
130                         HvLpEvent_Type_VirtualIo,
131                         viomajorsubtype_config | vioconfigget,
132                         HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
133                         viopath_sourceinst(viopath_hostLp),
134                         viopath_targetinst(viopath_hostLp),
135                         (u64)(unsigned long)&done, VIOVERSION << 16,
136                         ((u64)handle) << 32, HW_PAGE_SIZE, 0, 0);
137
138         if (hvrc != HvLpEvent_Rc_Good)
139                 printk(VIOPATH_KERN_WARN "hv error on op %d\n", (int)hvrc);
140
141         wait_for_completion(&done);
142
143         vlanMap = HvLpConfig_getVirtualLanIndexMap();
144
145         buf[HW_PAGE_SIZE-1] = '\0';
146         seq_printf(m, "%s", buf);
147
148         iseries_hv_unmap(handle, HW_PAGE_SIZE, DMA_FROM_DEVICE);
149         kfree(buf);
150
151         seq_printf(m, "AVAILABLE_VETH=%x\n", vlanMap);
152
153         node = of_find_node_by_path("/");
154         sysid = NULL;
155         if (node != NULL)
156                 sysid = of_get_property(node, "system-id", NULL);
157
158         if (sysid == NULL)
159                 seq_printf(m, "SRLNBR=<UNKNOWN>\n");
160         else
161                 /* Skip "IBM," on front of serial number, see dt.c */
162                 seq_printf(m, "SRLNBR=%s\n", sysid + 4);
163
164         of_node_put(node);
165
166         return 0;
167 }
168
169 static int proc_viopath_open(struct inode *inode, struct file *file)
170 {
171         return single_open(file, proc_viopath_show, NULL);
172 }
173
174 static const struct file_operations proc_viopath_operations = {
175         .open           = proc_viopath_open,
176         .read           = seq_read,
177         .llseek         = seq_lseek,
178         .release        = single_release,
179 };
180
181 static int __init vio_proc_init(void)
182 {
183         if (!firmware_has_feature(FW_FEATURE_ISERIES))
184                 return 0;
185
186         proc_create("iSeries/config", 0, NULL, &proc_viopath_operations);
187         return 0;
188 }
189 __initcall(vio_proc_init);
190
191 /* See if a given LP is active.  Allow for invalid lps to be passed in
192  * and just return invalid
193  */
194 int viopath_isactive(HvLpIndex lp)
195 {
196         if (lp == HvLpIndexInvalid)
197                 return 0;
198         if (lp < HVMAXARCHITECTEDLPS)
199                 return viopathStatus[lp].isActive;
200         else
201                 return 0;
202 }
203 EXPORT_SYMBOL(viopath_isactive);
204
205 /*
206  * We cache the source and target instance ids for each
207  * partition.
208  */
209 HvLpInstanceId viopath_sourceinst(HvLpIndex lp)
210 {
211         return viopathStatus[lp].mSourceInst;
212 }
213 EXPORT_SYMBOL(viopath_sourceinst);
214
215 HvLpInstanceId viopath_targetinst(HvLpIndex lp)
216 {
217         return viopathStatus[lp].mTargetInst;
218 }
219 EXPORT_SYMBOL(viopath_targetinst);
220
221 /*
222  * Send a monitor message.  This is a message with the acknowledge
223  * bit on that the other side will NOT explicitly acknowledge.  When
224  * the other side goes down, the hypervisor will acknowledge any
225  * outstanding messages....so we will know when the other side dies.
226  */
227 static void sendMonMsg(HvLpIndex remoteLp)
228 {
229         HvLpEvent_Rc hvrc;
230
231         viopathStatus[remoteLp].mSourceInst =
232                 HvCallEvent_getSourceLpInstanceId(remoteLp,
233                                 HvLpEvent_Type_VirtualIo);
234         viopathStatus[remoteLp].mTargetInst =
235                 HvCallEvent_getTargetLpInstanceId(remoteLp,
236                                 HvLpEvent_Type_VirtualIo);
237
238         /*
239          * Deliberately ignore the return code here.  if we call this
240          * more than once, we don't care.
241          */
242         vio_setHandler(viomajorsubtype_monitor, handleMonitorEvent);
243
244         hvrc = HvCallEvent_signalLpEventFast(remoteLp, HvLpEvent_Type_VirtualIo,
245                         viomajorsubtype_monitor, HvLpEvent_AckInd_DoAck,
246                         HvLpEvent_AckType_DeferredAck,
247                         viopathStatus[remoteLp].mSourceInst,
248                         viopathStatus[remoteLp].mTargetInst,
249                         viomonseq++, 0, 0, 0, 0, 0);
250
251         if (hvrc == HvLpEvent_Rc_Good)
252                 viopathStatus[remoteLp].isActive = 1;
253         else {
254                 printk(VIOPATH_KERN_WARN "could not connect to partition %d\n",
255                                 remoteLp);
256                 viopathStatus[remoteLp].isActive = 0;
257         }
258 }
259
260 static void handleMonitorEvent(struct HvLpEvent *event)
261 {
262         HvLpIndex remoteLp;
263         int i;
264
265         /*
266          * This handler is _also_ called as part of the loop
267          * at the end of this routine, so it must be able to
268          * ignore NULL events...
269          */
270         if (!event)
271                 return;
272
273         /*
274          * First see if this is just a normal monitor message from the
275          * other partition
276          */
277         if (hvlpevent_is_int(event)) {
278                 remoteLp = event->xSourceLp;
279                 if (!viopathStatus[remoteLp].isActive)
280                         sendMonMsg(remoteLp);
281                 return;
282         }
283
284         /*
285          * This path is for an acknowledgement; the other partition
286          * died
287          */
288         remoteLp = event->xTargetLp;
289         if ((event->xSourceInstanceId != viopathStatus[remoteLp].mSourceInst) ||
290             (event->xTargetInstanceId != viopathStatus[remoteLp].mTargetInst)) {
291                 printk(VIOPATH_KERN_WARN "ignoring ack....mismatched instances\n");
292                 return;
293         }
294
295         printk(VIOPATH_KERN_WARN "partition %d ended\n", remoteLp);
296
297         viopathStatus[remoteLp].isActive = 0;
298
299         /*
300          * For each active handler, pass them a NULL
301          * message to indicate that the other partition
302          * died
303          */
304         for (i = 0; i < VIO_MAX_SUBTYPES; i++) {
305                 if (vio_handler[i] != NULL)
306                         (*vio_handler[i])(NULL);
307         }
308 }
309
310 int vio_setHandler(int subtype, vio_event_handler_t *beh)
311 {
312         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
313         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
314                 return -EINVAL;
315         if (vio_handler[subtype] != NULL)
316                 return -EBUSY;
317         vio_handler[subtype] = beh;
318         return 0;
319 }
320 EXPORT_SYMBOL(vio_setHandler);
321
322 int vio_clearHandler(int subtype)
323 {
324         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
325         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
326                 return -EINVAL;
327         if (vio_handler[subtype] == NULL)
328                 return -EAGAIN;
329         vio_handler[subtype] = NULL;
330         return 0;
331 }
332 EXPORT_SYMBOL(vio_clearHandler);
333
334 static void handleConfig(struct HvLpEvent *event)
335 {
336         if (!event)
337                 return;
338         if (hvlpevent_is_int(event)) {
339                 printk(VIOPATH_KERN_WARN
340                        "unexpected config request from partition %d",
341                        event->xSourceLp);
342
343                 if (hvlpevent_need_ack(event)) {
344                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
345                         HvCallEvent_ackLpEvent(event);
346                 }
347                 return;
348         }
349
350         complete((struct completion *)event->xCorrelationToken);
351 }
352
353 /*
354  * Initialization of the hosting partition
355  */
356 void vio_set_hostlp(void)
357 {
358         /*
359          * If this has already been set then we DON'T want to either change
360          * it or re-register the proc file system
361          */
362         if (viopath_hostLp != HvLpIndexInvalid)
363                 return;
364
365         /*
366          * Figure out our hosting partition.  This isn't allowed to change
367          * while we're active
368          */
369         viopath_ourLp = HvLpConfig_getLpIndex();
370         viopath_hostLp = HvLpConfig_getHostingLpIndex(viopath_ourLp);
371
372         if (viopath_hostLp != HvLpIndexInvalid)
373                 vio_setHandler(viomajorsubtype_config, handleConfig);
374 }
375 EXPORT_SYMBOL(vio_set_hostlp);
376
377 static void vio_handleEvent(struct HvLpEvent *event)
378 {
379         HvLpIndex remoteLp;
380         int subtype = (event->xSubtype & VIOMAJOR_SUBTYPE_MASK)
381                 >> VIOMAJOR_SUBTYPE_SHIFT;
382
383         if (hvlpevent_is_int(event)) {
384                 remoteLp = event->xSourceLp;
385                 /*
386                  * The isActive is checked because if the hosting partition
387                  * went down and came back up it would not be active but it
388                  * would have different source and target instances, in which
389                  * case we'd want to reset them.  This case really protects
390                  * against an unauthorized active partition sending interrupts
391                  * or acks to this linux partition.
392                  */
393                 if (viopathStatus[remoteLp].isActive
394                     && (event->xSourceInstanceId !=
395                         viopathStatus[remoteLp].mTargetInst)) {
396                         printk(VIOPATH_KERN_WARN
397                                "message from invalid partition. "
398                                "int msg rcvd, source inst (%d) doesnt match (%d)\n",
399                                viopathStatus[remoteLp].mTargetInst,
400                                event->xSourceInstanceId);
401                         return;
402                 }
403
404                 if (viopathStatus[remoteLp].isActive
405                     && (event->xTargetInstanceId !=
406                         viopathStatus[remoteLp].mSourceInst)) {
407                         printk(VIOPATH_KERN_WARN
408                                "message from invalid partition. "
409                                "int msg rcvd, target inst (%d) doesnt match (%d)\n",
410                                viopathStatus[remoteLp].mSourceInst,
411                                event->xTargetInstanceId);
412                         return;
413                 }
414         } else {
415                 remoteLp = event->xTargetLp;
416                 if (event->xSourceInstanceId !=
417                     viopathStatus[remoteLp].mSourceInst) {
418                         printk(VIOPATH_KERN_WARN
419                                "message from invalid partition. "
420                                "ack msg rcvd, source inst (%d) doesnt match (%d)\n",
421                                viopathStatus[remoteLp].mSourceInst,
422                                event->xSourceInstanceId);
423                         return;
424                 }
425
426                 if (event->xTargetInstanceId !=
427                     viopathStatus[remoteLp].mTargetInst) {
428                         printk(VIOPATH_KERN_WARN
429                                "message from invalid partition. "
430                                "viopath: ack msg rcvd, target inst (%d) doesnt match (%d)\n",
431                                viopathStatus[remoteLp].mTargetInst,
432                                event->xTargetInstanceId);
433                         return;
434                 }
435         }
436
437         if (vio_handler[subtype] == NULL) {
438                 printk(VIOPATH_KERN_WARN
439                        "unexpected virtual io event subtype %d from partition %d\n",
440                        event->xSubtype, remoteLp);
441                 /* No handler.  Ack if necessary */
442                 if (hvlpevent_is_int(event) && hvlpevent_need_ack(event)) {
443                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
444                         HvCallEvent_ackLpEvent(event);
445                 }
446                 return;
447         }
448
449         /* This innocuous little line is where all the real work happens */
450         (*vio_handler[subtype])(event);
451 }
452
453 static void viopath_donealloc(void *parm, int number)
454 {
455         struct alloc_parms *parmsp = parm;
456
457         parmsp->number = number;
458         if (parmsp->used_wait_atomic)
459                 atomic_set(&parmsp->wait_atomic, 0);
460         else
461                 complete(&parmsp->done);
462 }
463
464 static int allocateEvents(HvLpIndex remoteLp, int numEvents)
465 {
466         struct alloc_parms parms;
467
468         if (system_state != SYSTEM_RUNNING) {
469                 parms.used_wait_atomic = 1;
470                 atomic_set(&parms.wait_atomic, 1);
471         } else {
472                 parms.used_wait_atomic = 0;
473                 init_completion(&parms.done);
474         }
475         mf_allocate_lp_events(remoteLp, HvLpEvent_Type_VirtualIo, 250,  /* It would be nice to put a real number here! */
476                             numEvents, &viopath_donealloc, &parms);
477         if (system_state != SYSTEM_RUNNING) {
478                 while (atomic_read(&parms.wait_atomic))
479                         mb();
480         } else
481                 wait_for_completion(&parms.done);
482         return parms.number;
483 }
484
485 int viopath_open(HvLpIndex remoteLp, int subtype, int numReq)
486 {
487         int i;
488         unsigned long flags;
489         int tempNumAllocated;
490
491         if ((remoteLp >= HVMAXARCHITECTEDLPS) || (remoteLp == HvLpIndexInvalid))
492                 return -EINVAL;
493
494         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
495         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
496                 return -EINVAL;
497
498         spin_lock_irqsave(&statuslock, flags);
499
500         if (!event_buffer_initialised) {
501                 for (i = 0; i < VIO_MAX_SUBTYPES; i++)
502                         atomic_set(&event_buffer_available[i], 1);
503                 event_buffer_initialised = 1;
504         }
505
506         viopathStatus[remoteLp].users[subtype]++;
507
508         if (!viopathStatus[remoteLp].isOpen) {
509                 viopathStatus[remoteLp].isOpen = 1;
510                 HvCallEvent_openLpEventPath(remoteLp, HvLpEvent_Type_VirtualIo);
511
512                 /*
513                  * Don't hold the spinlock during an operation that
514                  * can sleep.
515                  */
516                 spin_unlock_irqrestore(&statuslock, flags);
517                 tempNumAllocated = allocateEvents(remoteLp, 1);
518                 spin_lock_irqsave(&statuslock, flags);
519
520                 viopathStatus[remoteLp].numberAllocated += tempNumAllocated;
521
522                 if (viopathStatus[remoteLp].numberAllocated == 0) {
523                         HvCallEvent_closeLpEventPath(remoteLp,
524                                         HvLpEvent_Type_VirtualIo);
525
526                         spin_unlock_irqrestore(&statuslock, flags);
527                         return -ENOMEM;
528                 }
529
530                 viopathStatus[remoteLp].mSourceInst =
531                         HvCallEvent_getSourceLpInstanceId(remoteLp,
532                                         HvLpEvent_Type_VirtualIo);
533                 viopathStatus[remoteLp].mTargetInst =
534                         HvCallEvent_getTargetLpInstanceId(remoteLp,
535                                         HvLpEvent_Type_VirtualIo);
536                 HvLpEvent_registerHandler(HvLpEvent_Type_VirtualIo,
537                                           &vio_handleEvent);
538                 sendMonMsg(remoteLp);
539                 printk(VIOPATH_KERN_INFO "opening connection to partition %d, "
540                                 "setting sinst %d, tinst %d\n",
541                                 remoteLp, viopathStatus[remoteLp].mSourceInst,
542                                 viopathStatus[remoteLp].mTargetInst);
543         }
544
545         spin_unlock_irqrestore(&statuslock, flags);
546         tempNumAllocated = allocateEvents(remoteLp, numReq);
547         spin_lock_irqsave(&statuslock, flags);
548         viopathStatus[remoteLp].numberAllocated += tempNumAllocated;
549         spin_unlock_irqrestore(&statuslock, flags);
550
551         return 0;
552 }
553 EXPORT_SYMBOL(viopath_open);
554
555 int viopath_close(HvLpIndex remoteLp, int subtype, int numReq)
556 {
557         unsigned long flags;
558         int i;
559         int numOpen;
560         struct alloc_parms parms;
561
562         if ((remoteLp >= HVMAXARCHITECTEDLPS) || (remoteLp == HvLpIndexInvalid))
563                 return -EINVAL;
564
565         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
566         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
567                 return -EINVAL;
568
569         spin_lock_irqsave(&statuslock, flags);
570         /*
571          * If the viopath_close somehow gets called before a
572          * viopath_open it could decrement to -1 which is a non
573          * recoverable state so we'll prevent this from
574          * happening.
575          */
576         if (viopathStatus[remoteLp].users[subtype] > 0)
577                 viopathStatus[remoteLp].users[subtype]--;
578
579         spin_unlock_irqrestore(&statuslock, flags);
580
581         parms.used_wait_atomic = 0;
582         init_completion(&parms.done);
583         mf_deallocate_lp_events(remoteLp, HvLpEvent_Type_VirtualIo,
584                               numReq, &viopath_donealloc, &parms);
585         wait_for_completion(&parms.done);
586
587         spin_lock_irqsave(&statuslock, flags);
588         for (i = 0, numOpen = 0; i < VIO_MAX_SUBTYPES; i++)
589                 numOpen += viopathStatus[remoteLp].users[i];
590
591         if ((viopathStatus[remoteLp].isOpen) && (numOpen == 0)) {
592                 printk(VIOPATH_KERN_INFO "closing connection to partition %d\n",
593                                 remoteLp);
594
595                 HvCallEvent_closeLpEventPath(remoteLp,
596                                              HvLpEvent_Type_VirtualIo);
597                 viopathStatus[remoteLp].isOpen = 0;
598                 viopathStatus[remoteLp].isActive = 0;
599
600                 for (i = 0; i < VIO_MAX_SUBTYPES; i++)
601                         atomic_set(&event_buffer_available[i], 0);
602                 event_buffer_initialised = 0;
603         }
604         spin_unlock_irqrestore(&statuslock, flags);
605         return 0;
606 }
607 EXPORT_SYMBOL(viopath_close);
608
609 void *vio_get_event_buffer(int subtype)
610 {
611         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
612         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES))
613                 return NULL;
614
615         if (atomic_dec_if_positive(&event_buffer_available[subtype]) == 0)
616                 return &event_buffer[subtype * 256];
617         else
618                 return NULL;
619 }
620 EXPORT_SYMBOL(vio_get_event_buffer);
621
622 void vio_free_event_buffer(int subtype, void *buffer)
623 {
624         subtype = subtype >> VIOMAJOR_SUBTYPE_SHIFT;
625         if ((subtype < 0) || (subtype >= VIO_MAX_SUBTYPES)) {
626                 printk(VIOPATH_KERN_WARN
627                        "unexpected subtype %d freeing event buffer\n", subtype);
628                 return;
629         }
630
631         if (atomic_read(&event_buffer_available[subtype]) != 0) {
632                 printk(VIOPATH_KERN_WARN
633                        "freeing unallocated event buffer, subtype %d\n",
634                        subtype);
635                 return;
636         }
637
638         if (buffer != &event_buffer[subtype * 256]) {
639                 printk(VIOPATH_KERN_WARN
640                        "freeing invalid event buffer, subtype %d\n", subtype);
641         }
642
643         atomic_set(&event_buffer_available[subtype], 1);
644 }
645 EXPORT_SYMBOL(vio_free_event_buffer);
646
647 static const struct vio_error_entry vio_no_error =
648     { 0, 0, "Non-VIO Error" };
649 static const struct vio_error_entry vio_unknown_error =
650     { 0, EIO, "Unknown Error" };
651
652 static const struct vio_error_entry vio_default_errors[] = {
653         {0x0001, EIO, "No Connection"},
654         {0x0002, EIO, "No Receiver"},
655         {0x0003, EIO, "No Buffer Available"},
656         {0x0004, EBADRQC, "Invalid Message Type"},
657         {0x0000, 0, NULL},
658 };
659
660 const struct vio_error_entry *vio_lookup_rc(
661                 const struct vio_error_entry *local_table, u16 rc)
662 {
663         const struct vio_error_entry *cur;
664
665         if (!rc)
666                 return &vio_no_error;
667         if (local_table)
668                 for (cur = local_table; cur->rc; ++cur)
669                         if (cur->rc == rc)
670                                 return cur;
671         for (cur = vio_default_errors; cur->rc; ++cur)
672                 if (cur->rc == rc)
673                         return cur;
674         return &vio_unknown_error;
675 }
676 EXPORT_SYMBOL(vio_lookup_rc);