ARM: 6214/2: driver for the character LCD found in ARM refdesigns
[linux-2.6.git] / drivers / misc / sgi-xp / xpc_channel.c
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (c) 2004-2009 Silicon Graphics, Inc.  All Rights Reserved.
7  */
8
9 /*
10  * Cross Partition Communication (XPC) channel support.
11  *
12  *      This is the part of XPC that manages the channels and
13  *      sends/receives messages across them to/from other partitions.
14  *
15  */
16
17 #include <linux/device.h>
18 #include "xpc.h"
19
20 /*
21  * Process a connect message from a remote partition.
22  *
23  * Note: xpc_process_connect() is expecting to be called with the
24  * spin_lock_irqsave held and will leave it locked upon return.
25  */
26 static void
27 xpc_process_connect(struct xpc_channel *ch, unsigned long *irq_flags)
28 {
29         enum xp_retval ret;
30
31         DBUG_ON(!spin_is_locked(&ch->lock));
32
33         if (!(ch->flags & XPC_C_OPENREQUEST) ||
34             !(ch->flags & XPC_C_ROPENREQUEST)) {
35                 /* nothing more to do for now */
36                 return;
37         }
38         DBUG_ON(!(ch->flags & XPC_C_CONNECTING));
39
40         if (!(ch->flags & XPC_C_SETUP)) {
41                 spin_unlock_irqrestore(&ch->lock, *irq_flags);
42                 ret = xpc_arch_ops.setup_msg_structures(ch);
43                 spin_lock_irqsave(&ch->lock, *irq_flags);
44
45                 if (ret != xpSuccess)
46                         XPC_DISCONNECT_CHANNEL(ch, ret, irq_flags);
47                 else
48                         ch->flags |= XPC_C_SETUP;
49
50                 if (ch->flags & XPC_C_DISCONNECTING)
51                         return;
52         }
53
54         if (!(ch->flags & XPC_C_OPENREPLY)) {
55                 ch->flags |= XPC_C_OPENREPLY;
56                 xpc_arch_ops.send_chctl_openreply(ch, irq_flags);
57         }
58
59         if (!(ch->flags & XPC_C_ROPENREPLY))
60                 return;
61
62         if (!(ch->flags & XPC_C_OPENCOMPLETE)) {
63                 ch->flags |= (XPC_C_OPENCOMPLETE | XPC_C_CONNECTED);
64                 xpc_arch_ops.send_chctl_opencomplete(ch, irq_flags);
65         }
66
67         if (!(ch->flags & XPC_C_ROPENCOMPLETE))
68                 return;
69
70         dev_info(xpc_chan, "channel %d to partition %d connected\n",
71                  ch->number, ch->partid);
72
73         ch->flags = (XPC_C_CONNECTED | XPC_C_SETUP);    /* clear all else */
74 }
75
76 /*
77  * spin_lock_irqsave() is expected to be held on entry.
78  */
79 static void
80 xpc_process_disconnect(struct xpc_channel *ch, unsigned long *irq_flags)
81 {
82         struct xpc_partition *part = &xpc_partitions[ch->partid];
83         u32 channel_was_connected = (ch->flags & XPC_C_WASCONNECTED);
84
85         DBUG_ON(!spin_is_locked(&ch->lock));
86
87         if (!(ch->flags & XPC_C_DISCONNECTING))
88                 return;
89
90         DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
91
92         /* make sure all activity has settled down first */
93
94         if (atomic_read(&ch->kthreads_assigned) > 0 ||
95             atomic_read(&ch->references) > 0) {
96                 return;
97         }
98         DBUG_ON((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
99                 !(ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE));
100
101         if (part->act_state == XPC_P_AS_DEACTIVATING) {
102                 /* can't proceed until the other side disengages from us */
103                 if (xpc_arch_ops.partition_engaged(ch->partid))
104                         return;
105
106         } else {
107
108                 /* as long as the other side is up do the full protocol */
109
110                 if (!(ch->flags & XPC_C_RCLOSEREQUEST))
111                         return;
112
113                 if (!(ch->flags & XPC_C_CLOSEREPLY)) {
114                         ch->flags |= XPC_C_CLOSEREPLY;
115                         xpc_arch_ops.send_chctl_closereply(ch, irq_flags);
116                 }
117
118                 if (!(ch->flags & XPC_C_RCLOSEREPLY))
119                         return;
120         }
121
122         /* wake those waiting for notify completion */
123         if (atomic_read(&ch->n_to_notify) > 0) {
124                 /* we do callout while holding ch->lock, callout can't block */
125                 xpc_arch_ops.notify_senders_of_disconnect(ch);
126         }
127
128         /* both sides are disconnected now */
129
130         if (ch->flags & XPC_C_DISCONNECTINGCALLOUT_MADE) {
131                 spin_unlock_irqrestore(&ch->lock, *irq_flags);
132                 xpc_disconnect_callout(ch, xpDisconnected);
133                 spin_lock_irqsave(&ch->lock, *irq_flags);
134         }
135
136         DBUG_ON(atomic_read(&ch->n_to_notify) != 0);
137
138         /* it's now safe to free the channel's message queues */
139         xpc_arch_ops.teardown_msg_structures(ch);
140
141         ch->func = NULL;
142         ch->key = NULL;
143         ch->entry_size = 0;
144         ch->local_nentries = 0;
145         ch->remote_nentries = 0;
146         ch->kthreads_assigned_limit = 0;
147         ch->kthreads_idle_limit = 0;
148
149         /*
150          * Mark the channel disconnected and clear all other flags, including
151          * XPC_C_SETUP (because of call to
152          * xpc_arch_ops.teardown_msg_structures()) but not including
153          * XPC_C_WDISCONNECT (if it was set).
154          */
155         ch->flags = (XPC_C_DISCONNECTED | (ch->flags & XPC_C_WDISCONNECT));
156
157         atomic_dec(&part->nchannels_active);
158
159         if (channel_was_connected) {
160                 dev_info(xpc_chan, "channel %d to partition %d disconnected, "
161                          "reason=%d\n", ch->number, ch->partid, ch->reason);
162         }
163
164         if (ch->flags & XPC_C_WDISCONNECT) {
165                 /* we won't lose the CPU since we're holding ch->lock */
166                 complete(&ch->wdisconnect_wait);
167         } else if (ch->delayed_chctl_flags) {
168                 if (part->act_state != XPC_P_AS_DEACTIVATING) {
169                         /* time to take action on any delayed chctl flags */
170                         spin_lock(&part->chctl_lock);
171                         part->chctl.flags[ch->number] |=
172                             ch->delayed_chctl_flags;
173                         spin_unlock(&part->chctl_lock);
174                 }
175                 ch->delayed_chctl_flags = 0;
176         }
177 }
178
179 /*
180  * Process a change in the channel's remote connection state.
181  */
182 static void
183 xpc_process_openclose_chctl_flags(struct xpc_partition *part, int ch_number,
184                                   u8 chctl_flags)
185 {
186         unsigned long irq_flags;
187         struct xpc_openclose_args *args =
188             &part->remote_openclose_args[ch_number];
189         struct xpc_channel *ch = &part->channels[ch_number];
190         enum xp_retval reason;
191         enum xp_retval ret;
192         int create_kthread = 0;
193
194         spin_lock_irqsave(&ch->lock, irq_flags);
195
196 again:
197
198         if ((ch->flags & XPC_C_DISCONNECTED) &&
199             (ch->flags & XPC_C_WDISCONNECT)) {
200                 /*
201                  * Delay processing chctl flags until thread waiting disconnect
202                  * has had a chance to see that the channel is disconnected.
203                  */
204                 ch->delayed_chctl_flags |= chctl_flags;
205                 goto out;
206         }
207
208         if (chctl_flags & XPC_CHCTL_CLOSEREQUEST) {
209
210                 dev_dbg(xpc_chan, "XPC_CHCTL_CLOSEREQUEST (reason=%d) received "
211                         "from partid=%d, channel=%d\n", args->reason,
212                         ch->partid, ch->number);
213
214                 /*
215                  * If RCLOSEREQUEST is set, we're probably waiting for
216                  * RCLOSEREPLY. We should find it and a ROPENREQUEST packed
217                  * with this RCLOSEREQUEST in the chctl_flags.
218                  */
219
220                 if (ch->flags & XPC_C_RCLOSEREQUEST) {
221                         DBUG_ON(!(ch->flags & XPC_C_DISCONNECTING));
222                         DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
223                         DBUG_ON(!(ch->flags & XPC_C_CLOSEREPLY));
224                         DBUG_ON(ch->flags & XPC_C_RCLOSEREPLY);
225
226                         DBUG_ON(!(chctl_flags & XPC_CHCTL_CLOSEREPLY));
227                         chctl_flags &= ~XPC_CHCTL_CLOSEREPLY;
228                         ch->flags |= XPC_C_RCLOSEREPLY;
229
230                         /* both sides have finished disconnecting */
231                         xpc_process_disconnect(ch, &irq_flags);
232                         DBUG_ON(!(ch->flags & XPC_C_DISCONNECTED));
233                         goto again;
234                 }
235
236                 if (ch->flags & XPC_C_DISCONNECTED) {
237                         if (!(chctl_flags & XPC_CHCTL_OPENREQUEST)) {
238                                 if (part->chctl.flags[ch_number] &
239                                     XPC_CHCTL_OPENREQUEST) {
240
241                                         DBUG_ON(ch->delayed_chctl_flags != 0);
242                                         spin_lock(&part->chctl_lock);
243                                         part->chctl.flags[ch_number] |=
244                                             XPC_CHCTL_CLOSEREQUEST;
245                                         spin_unlock(&part->chctl_lock);
246                                 }
247                                 goto out;
248                         }
249
250                         XPC_SET_REASON(ch, 0, 0);
251                         ch->flags &= ~XPC_C_DISCONNECTED;
252
253                         atomic_inc(&part->nchannels_active);
254                         ch->flags |= (XPC_C_CONNECTING | XPC_C_ROPENREQUEST);
255                 }
256
257                 chctl_flags &= ~(XPC_CHCTL_OPENREQUEST | XPC_CHCTL_OPENREPLY |
258                     XPC_CHCTL_OPENCOMPLETE);
259
260                 /*
261                  * The meaningful CLOSEREQUEST connection state fields are:
262                  *      reason = reason connection is to be closed
263                  */
264
265                 ch->flags |= XPC_C_RCLOSEREQUEST;
266
267                 if (!(ch->flags & XPC_C_DISCONNECTING)) {
268                         reason = args->reason;
269                         if (reason <= xpSuccess || reason > xpUnknownReason)
270                                 reason = xpUnknownReason;
271                         else if (reason == xpUnregistering)
272                                 reason = xpOtherUnregistering;
273
274                         XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
275
276                         DBUG_ON(chctl_flags & XPC_CHCTL_CLOSEREPLY);
277                         goto out;
278                 }
279
280                 xpc_process_disconnect(ch, &irq_flags);
281         }
282
283         if (chctl_flags & XPC_CHCTL_CLOSEREPLY) {
284
285                 dev_dbg(xpc_chan, "XPC_CHCTL_CLOSEREPLY received from partid="
286                         "%d, channel=%d\n", ch->partid, ch->number);
287
288                 if (ch->flags & XPC_C_DISCONNECTED) {
289                         DBUG_ON(part->act_state != XPC_P_AS_DEACTIVATING);
290                         goto out;
291                 }
292
293                 DBUG_ON(!(ch->flags & XPC_C_CLOSEREQUEST));
294
295                 if (!(ch->flags & XPC_C_RCLOSEREQUEST)) {
296                         if (part->chctl.flags[ch_number] &
297                             XPC_CHCTL_CLOSEREQUEST) {
298
299                                 DBUG_ON(ch->delayed_chctl_flags != 0);
300                                 spin_lock(&part->chctl_lock);
301                                 part->chctl.flags[ch_number] |=
302                                     XPC_CHCTL_CLOSEREPLY;
303                                 spin_unlock(&part->chctl_lock);
304                         }
305                         goto out;
306                 }
307
308                 ch->flags |= XPC_C_RCLOSEREPLY;
309
310                 if (ch->flags & XPC_C_CLOSEREPLY) {
311                         /* both sides have finished disconnecting */
312                         xpc_process_disconnect(ch, &irq_flags);
313                 }
314         }
315
316         if (chctl_flags & XPC_CHCTL_OPENREQUEST) {
317
318                 dev_dbg(xpc_chan, "XPC_CHCTL_OPENREQUEST (entry_size=%d, "
319                         "local_nentries=%d) received from partid=%d, "
320                         "channel=%d\n", args->entry_size, args->local_nentries,
321                         ch->partid, ch->number);
322
323                 if (part->act_state == XPC_P_AS_DEACTIVATING ||
324                     (ch->flags & XPC_C_ROPENREQUEST)) {
325                         goto out;
326                 }
327
328                 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_WDISCONNECT)) {
329                         ch->delayed_chctl_flags |= XPC_CHCTL_OPENREQUEST;
330                         goto out;
331                 }
332                 DBUG_ON(!(ch->flags & (XPC_C_DISCONNECTED |
333                                        XPC_C_OPENREQUEST)));
334                 DBUG_ON(ch->flags & (XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY |
335                                      XPC_C_OPENREPLY | XPC_C_CONNECTED));
336
337                 /*
338                  * The meaningful OPENREQUEST connection state fields are:
339                  *      entry_size = size of channel's messages in bytes
340                  *      local_nentries = remote partition's local_nentries
341                  */
342                 if (args->entry_size == 0 || args->local_nentries == 0) {
343                         /* assume OPENREQUEST was delayed by mistake */
344                         goto out;
345                 }
346
347                 ch->flags |= (XPC_C_ROPENREQUEST | XPC_C_CONNECTING);
348                 ch->remote_nentries = args->local_nentries;
349
350                 if (ch->flags & XPC_C_OPENREQUEST) {
351                         if (args->entry_size != ch->entry_size) {
352                                 XPC_DISCONNECT_CHANNEL(ch, xpUnequalMsgSizes,
353                                                        &irq_flags);
354                                 goto out;
355                         }
356                 } else {
357                         ch->entry_size = args->entry_size;
358
359                         XPC_SET_REASON(ch, 0, 0);
360                         ch->flags &= ~XPC_C_DISCONNECTED;
361
362                         atomic_inc(&part->nchannels_active);
363                 }
364
365                 xpc_process_connect(ch, &irq_flags);
366         }
367
368         if (chctl_flags & XPC_CHCTL_OPENREPLY) {
369
370                 dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY (local_msgqueue_pa="
371                         "0x%lx, local_nentries=%d, remote_nentries=%d) "
372                         "received from partid=%d, channel=%d\n",
373                         args->local_msgqueue_pa, args->local_nentries,
374                         args->remote_nentries, ch->partid, ch->number);
375
376                 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
377                         goto out;
378
379                 if (!(ch->flags & XPC_C_OPENREQUEST)) {
380                         XPC_DISCONNECT_CHANNEL(ch, xpOpenCloseError,
381                                                &irq_flags);
382                         goto out;
383                 }
384
385                 DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));
386                 DBUG_ON(ch->flags & XPC_C_CONNECTED);
387
388                 /*
389                  * The meaningful OPENREPLY connection state fields are:
390                  *      local_msgqueue_pa = physical address of remote
391                  *                          partition's local_msgqueue
392                  *      local_nentries = remote partition's local_nentries
393                  *      remote_nentries = remote partition's remote_nentries
394                  */
395                 DBUG_ON(args->local_msgqueue_pa == 0);
396                 DBUG_ON(args->local_nentries == 0);
397                 DBUG_ON(args->remote_nentries == 0);
398
399                 ret = xpc_arch_ops.save_remote_msgqueue_pa(ch,
400                                                       args->local_msgqueue_pa);
401                 if (ret != xpSuccess) {
402                         XPC_DISCONNECT_CHANNEL(ch, ret, &irq_flags);
403                         goto out;
404                 }
405                 ch->flags |= XPC_C_ROPENREPLY;
406
407                 if (args->local_nentries < ch->remote_nentries) {
408                         dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY: new "
409                                 "remote_nentries=%d, old remote_nentries=%d, "
410                                 "partid=%d, channel=%d\n",
411                                 args->local_nentries, ch->remote_nentries,
412                                 ch->partid, ch->number);
413
414                         ch->remote_nentries = args->local_nentries;
415                 }
416                 if (args->remote_nentries < ch->local_nentries) {
417                         dev_dbg(xpc_chan, "XPC_CHCTL_OPENREPLY: new "
418                                 "local_nentries=%d, old local_nentries=%d, "
419                                 "partid=%d, channel=%d\n",
420                                 args->remote_nentries, ch->local_nentries,
421                                 ch->partid, ch->number);
422
423                         ch->local_nentries = args->remote_nentries;
424                 }
425
426                 xpc_process_connect(ch, &irq_flags);
427         }
428
429         if (chctl_flags & XPC_CHCTL_OPENCOMPLETE) {
430
431                 dev_dbg(xpc_chan, "XPC_CHCTL_OPENCOMPLETE received from "
432                         "partid=%d, channel=%d\n", ch->partid, ch->number);
433
434                 if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
435                         goto out;
436
437                 if (!(ch->flags & XPC_C_OPENREQUEST) ||
438                     !(ch->flags & XPC_C_OPENREPLY)) {
439                         XPC_DISCONNECT_CHANNEL(ch, xpOpenCloseError,
440                                                &irq_flags);
441                         goto out;
442                 }
443
444                 DBUG_ON(!(ch->flags & XPC_C_ROPENREQUEST));
445                 DBUG_ON(!(ch->flags & XPC_C_ROPENREPLY));
446                 DBUG_ON(!(ch->flags & XPC_C_CONNECTED));
447
448                 ch->flags |= XPC_C_ROPENCOMPLETE;
449
450                 xpc_process_connect(ch, &irq_flags);
451                 create_kthread = 1;
452         }
453
454 out:
455         spin_unlock_irqrestore(&ch->lock, irq_flags);
456
457         if (create_kthread)
458                 xpc_create_kthreads(ch, 1, 0);
459 }
460
461 /*
462  * Attempt to establish a channel connection to a remote partition.
463  */
464 static enum xp_retval
465 xpc_connect_channel(struct xpc_channel *ch)
466 {
467         unsigned long irq_flags;
468         struct xpc_registration *registration = &xpc_registrations[ch->number];
469
470         if (mutex_trylock(&registration->mutex) == 0)
471                 return xpRetry;
472
473         if (!XPC_CHANNEL_REGISTERED(ch->number)) {
474                 mutex_unlock(&registration->mutex);
475                 return xpUnregistered;
476         }
477
478         spin_lock_irqsave(&ch->lock, irq_flags);
479
480         DBUG_ON(ch->flags & XPC_C_CONNECTED);
481         DBUG_ON(ch->flags & XPC_C_OPENREQUEST);
482
483         if (ch->flags & XPC_C_DISCONNECTING) {
484                 spin_unlock_irqrestore(&ch->lock, irq_flags);
485                 mutex_unlock(&registration->mutex);
486                 return ch->reason;
487         }
488
489         /* add info from the channel connect registration to the channel */
490
491         ch->kthreads_assigned_limit = registration->assigned_limit;
492         ch->kthreads_idle_limit = registration->idle_limit;
493         DBUG_ON(atomic_read(&ch->kthreads_assigned) != 0);
494         DBUG_ON(atomic_read(&ch->kthreads_idle) != 0);
495         DBUG_ON(atomic_read(&ch->kthreads_active) != 0);
496
497         ch->func = registration->func;
498         DBUG_ON(registration->func == NULL);
499         ch->key = registration->key;
500
501         ch->local_nentries = registration->nentries;
502
503         if (ch->flags & XPC_C_ROPENREQUEST) {
504                 if (registration->entry_size != ch->entry_size) {
505                         /* the local and remote sides aren't the same */
506
507                         /*
508                          * Because XPC_DISCONNECT_CHANNEL() can block we're
509                          * forced to up the registration sema before we unlock
510                          * the channel lock. But that's okay here because we're
511                          * done with the part that required the registration
512                          * sema. XPC_DISCONNECT_CHANNEL() requires that the
513                          * channel lock be locked and will unlock and relock
514                          * the channel lock as needed.
515                          */
516                         mutex_unlock(&registration->mutex);
517                         XPC_DISCONNECT_CHANNEL(ch, xpUnequalMsgSizes,
518                                                &irq_flags);
519                         spin_unlock_irqrestore(&ch->lock, irq_flags);
520                         return xpUnequalMsgSizes;
521                 }
522         } else {
523                 ch->entry_size = registration->entry_size;
524
525                 XPC_SET_REASON(ch, 0, 0);
526                 ch->flags &= ~XPC_C_DISCONNECTED;
527
528                 atomic_inc(&xpc_partitions[ch->partid].nchannels_active);
529         }
530
531         mutex_unlock(&registration->mutex);
532
533         /* initiate the connection */
534
535         ch->flags |= (XPC_C_OPENREQUEST | XPC_C_CONNECTING);
536         xpc_arch_ops.send_chctl_openrequest(ch, &irq_flags);
537
538         xpc_process_connect(ch, &irq_flags);
539
540         spin_unlock_irqrestore(&ch->lock, irq_flags);
541
542         return xpSuccess;
543 }
544
545 void
546 xpc_process_sent_chctl_flags(struct xpc_partition *part)
547 {
548         unsigned long irq_flags;
549         union xpc_channel_ctl_flags chctl;
550         struct xpc_channel *ch;
551         int ch_number;
552         u32 ch_flags;
553
554         chctl.all_flags = xpc_arch_ops.get_chctl_all_flags(part);
555
556         /*
557          * Initiate channel connections for registered channels.
558          *
559          * For each connected channel that has pending messages activate idle
560          * kthreads and/or create new kthreads as needed.
561          */
562
563         for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
564                 ch = &part->channels[ch_number];
565
566                 /*
567                  * Process any open or close related chctl flags, and then deal
568                  * with connecting or disconnecting the channel as required.
569                  */
570
571                 if (chctl.flags[ch_number] & XPC_OPENCLOSE_CHCTL_FLAGS) {
572                         xpc_process_openclose_chctl_flags(part, ch_number,
573                                                         chctl.flags[ch_number]);
574                 }
575
576                 ch_flags = ch->flags;   /* need an atomic snapshot of flags */
577
578                 if (ch_flags & XPC_C_DISCONNECTING) {
579                         spin_lock_irqsave(&ch->lock, irq_flags);
580                         xpc_process_disconnect(ch, &irq_flags);
581                         spin_unlock_irqrestore(&ch->lock, irq_flags);
582                         continue;
583                 }
584
585                 if (part->act_state == XPC_P_AS_DEACTIVATING)
586                         continue;
587
588                 if (!(ch_flags & XPC_C_CONNECTED)) {
589                         if (!(ch_flags & XPC_C_OPENREQUEST)) {
590                                 DBUG_ON(ch_flags & XPC_C_SETUP);
591                                 (void)xpc_connect_channel(ch);
592                         }
593                         continue;
594                 }
595
596                 /*
597                  * Process any message related chctl flags, this may involve
598                  * the activation of kthreads to deliver any pending messages
599                  * sent from the other partition.
600                  */
601
602                 if (chctl.flags[ch_number] & XPC_MSG_CHCTL_FLAGS)
603                         xpc_arch_ops.process_msg_chctl_flags(part, ch_number);
604         }
605 }
606
607 /*
608  * XPC's heartbeat code calls this function to inform XPC that a partition is
609  * going down.  XPC responds by tearing down the XPartition Communication
610  * infrastructure used for the just downed partition.
611  *
612  * XPC's heartbeat code will never call this function and xpc_partition_up()
613  * at the same time. Nor will it ever make multiple calls to either function
614  * at the same time.
615  */
616 void
617 xpc_partition_going_down(struct xpc_partition *part, enum xp_retval reason)
618 {
619         unsigned long irq_flags;
620         int ch_number;
621         struct xpc_channel *ch;
622
623         dev_dbg(xpc_chan, "deactivating partition %d, reason=%d\n",
624                 XPC_PARTID(part), reason);
625
626         if (!xpc_part_ref(part)) {
627                 /* infrastructure for this partition isn't currently set up */
628                 return;
629         }
630
631         /* disconnect channels associated with the partition going down */
632
633         for (ch_number = 0; ch_number < part->nchannels; ch_number++) {
634                 ch = &part->channels[ch_number];
635
636                 xpc_msgqueue_ref(ch);
637                 spin_lock_irqsave(&ch->lock, irq_flags);
638
639                 XPC_DISCONNECT_CHANNEL(ch, reason, &irq_flags);
640
641                 spin_unlock_irqrestore(&ch->lock, irq_flags);
642                 xpc_msgqueue_deref(ch);
643         }
644
645         xpc_wakeup_channel_mgr(part);
646
647         xpc_part_deref(part);
648 }
649
650 /*
651  * Called by XP at the time of channel connection registration to cause
652  * XPC to establish connections to all currently active partitions.
653  */
654 void
655 xpc_initiate_connect(int ch_number)
656 {
657         short partid;
658         struct xpc_partition *part;
659         struct xpc_channel *ch;
660
661         DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
662
663         for (partid = 0; partid < xp_max_npartitions; partid++) {
664                 part = &xpc_partitions[partid];
665
666                 if (xpc_part_ref(part)) {
667                         ch = &part->channels[ch_number];
668
669                         /*
670                          * Initiate the establishment of a connection on the
671                          * newly registered channel to the remote partition.
672                          */
673                         xpc_wakeup_channel_mgr(part);
674                         xpc_part_deref(part);
675                 }
676         }
677 }
678
679 void
680 xpc_connected_callout(struct xpc_channel *ch)
681 {
682         /* let the registerer know that a connection has been established */
683
684         if (ch->func != NULL) {
685                 dev_dbg(xpc_chan, "ch->func() called, reason=xpConnected, "
686                         "partid=%d, channel=%d\n", ch->partid, ch->number);
687
688                 ch->func(xpConnected, ch->partid, ch->number,
689                          (void *)(u64)ch->local_nentries, ch->key);
690
691                 dev_dbg(xpc_chan, "ch->func() returned, reason=xpConnected, "
692                         "partid=%d, channel=%d\n", ch->partid, ch->number);
693         }
694 }
695
696 /*
697  * Called by XP at the time of channel connection unregistration to cause
698  * XPC to teardown all current connections for the specified channel.
699  *
700  * Before returning xpc_initiate_disconnect() will wait until all connections
701  * on the specified channel have been closed/torndown. So the caller can be
702  * assured that they will not be receiving any more callouts from XPC to the
703  * function they registered via xpc_connect().
704  *
705  * Arguments:
706  *
707  *      ch_number - channel # to unregister.
708  */
709 void
710 xpc_initiate_disconnect(int ch_number)
711 {
712         unsigned long irq_flags;
713         short partid;
714         struct xpc_partition *part;
715         struct xpc_channel *ch;
716
717         DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
718
719         /* initiate the channel disconnect for every active partition */
720         for (partid = 0; partid < xp_max_npartitions; partid++) {
721                 part = &xpc_partitions[partid];
722
723                 if (xpc_part_ref(part)) {
724                         ch = &part->channels[ch_number];
725                         xpc_msgqueue_ref(ch);
726
727                         spin_lock_irqsave(&ch->lock, irq_flags);
728
729                         if (!(ch->flags & XPC_C_DISCONNECTED)) {
730                                 ch->flags |= XPC_C_WDISCONNECT;
731
732                                 XPC_DISCONNECT_CHANNEL(ch, xpUnregistering,
733                                                        &irq_flags);
734                         }
735
736                         spin_unlock_irqrestore(&ch->lock, irq_flags);
737
738                         xpc_msgqueue_deref(ch);
739                         xpc_part_deref(part);
740                 }
741         }
742
743         xpc_disconnect_wait(ch_number);
744 }
745
746 /*
747  * To disconnect a channel, and reflect it back to all who may be waiting.
748  *
749  * An OPEN is not allowed until XPC_C_DISCONNECTING is cleared by
750  * xpc_process_disconnect(), and if set, XPC_C_WDISCONNECT is cleared by
751  * xpc_disconnect_wait().
752  *
753  * THE CHANNEL IS TO BE LOCKED BY THE CALLER AND WILL REMAIN LOCKED UPON RETURN.
754  */
755 void
756 xpc_disconnect_channel(const int line, struct xpc_channel *ch,
757                        enum xp_retval reason, unsigned long *irq_flags)
758 {
759         u32 channel_was_connected = (ch->flags & XPC_C_CONNECTED);
760
761         DBUG_ON(!spin_is_locked(&ch->lock));
762
763         if (ch->flags & (XPC_C_DISCONNECTING | XPC_C_DISCONNECTED))
764                 return;
765
766         DBUG_ON(!(ch->flags & (XPC_C_CONNECTING | XPC_C_CONNECTED)));
767
768         dev_dbg(xpc_chan, "reason=%d, line=%d, partid=%d, channel=%d\n",
769                 reason, line, ch->partid, ch->number);
770
771         XPC_SET_REASON(ch, reason, line);
772
773         ch->flags |= (XPC_C_CLOSEREQUEST | XPC_C_DISCONNECTING);
774         /* some of these may not have been set */
775         ch->flags &= ~(XPC_C_OPENREQUEST | XPC_C_OPENREPLY |
776                        XPC_C_ROPENREQUEST | XPC_C_ROPENREPLY |
777                        XPC_C_CONNECTING | XPC_C_CONNECTED);
778
779         xpc_arch_ops.send_chctl_closerequest(ch, irq_flags);
780
781         if (channel_was_connected)
782                 ch->flags |= XPC_C_WASCONNECTED;
783
784         spin_unlock_irqrestore(&ch->lock, *irq_flags);
785
786         /* wake all idle kthreads so they can exit */
787         if (atomic_read(&ch->kthreads_idle) > 0) {
788                 wake_up_all(&ch->idle_wq);
789
790         } else if ((ch->flags & XPC_C_CONNECTEDCALLOUT_MADE) &&
791                    !(ch->flags & XPC_C_DISCONNECTINGCALLOUT)) {
792                 /* start a kthread that will do the xpDisconnecting callout */
793                 xpc_create_kthreads(ch, 1, 1);
794         }
795
796         /* wake those waiting to allocate an entry from the local msg queue */
797         if (atomic_read(&ch->n_on_msg_allocate_wq) > 0)
798                 wake_up(&ch->msg_allocate_wq);
799
800         spin_lock_irqsave(&ch->lock, *irq_flags);
801 }
802
803 void
804 xpc_disconnect_callout(struct xpc_channel *ch, enum xp_retval reason)
805 {
806         /*
807          * Let the channel's registerer know that the channel is being
808          * disconnected. We don't want to do this if the registerer was never
809          * informed of a connection being made.
810          */
811
812         if (ch->func != NULL) {
813                 dev_dbg(xpc_chan, "ch->func() called, reason=%d, partid=%d, "
814                         "channel=%d\n", reason, ch->partid, ch->number);
815
816                 ch->func(reason, ch->partid, ch->number, NULL, ch->key);
817
818                 dev_dbg(xpc_chan, "ch->func() returned, reason=%d, partid=%d, "
819                         "channel=%d\n", reason, ch->partid, ch->number);
820         }
821 }
822
823 /*
824  * Wait for a message entry to become available for the specified channel,
825  * but don't wait any longer than 1 jiffy.
826  */
827 enum xp_retval
828 xpc_allocate_msg_wait(struct xpc_channel *ch)
829 {
830         enum xp_retval ret;
831
832         if (ch->flags & XPC_C_DISCONNECTING) {
833                 DBUG_ON(ch->reason == xpInterrupted);
834                 return ch->reason;
835         }
836
837         atomic_inc(&ch->n_on_msg_allocate_wq);
838         ret = interruptible_sleep_on_timeout(&ch->msg_allocate_wq, 1);
839         atomic_dec(&ch->n_on_msg_allocate_wq);
840
841         if (ch->flags & XPC_C_DISCONNECTING) {
842                 ret = ch->reason;
843                 DBUG_ON(ch->reason == xpInterrupted);
844         } else if (ret == 0) {
845                 ret = xpTimeout;
846         } else {
847                 ret = xpInterrupted;
848         }
849
850         return ret;
851 }
852
853 /*
854  * Send a message that contains the user's payload on the specified channel
855  * connected to the specified partition.
856  *
857  * NOTE that this routine can sleep waiting for a message entry to become
858  * available. To not sleep, pass in the XPC_NOWAIT flag.
859  *
860  * Once sent, this routine will not wait for the message to be received, nor
861  * will notification be given when it does happen.
862  *
863  * Arguments:
864  *
865  *      partid - ID of partition to which the channel is connected.
866  *      ch_number - channel # to send message on.
867  *      flags - see xp.h for valid flags.
868  *      payload - pointer to the payload which is to be sent.
869  *      payload_size - size of the payload in bytes.
870  */
871 enum xp_retval
872 xpc_initiate_send(short partid, int ch_number, u32 flags, void *payload,
873                   u16 payload_size)
874 {
875         struct xpc_partition *part = &xpc_partitions[partid];
876         enum xp_retval ret = xpUnknownReason;
877
878         dev_dbg(xpc_chan, "payload=0x%p, partid=%d, channel=%d\n", payload,
879                 partid, ch_number);
880
881         DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
882         DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
883         DBUG_ON(payload == NULL);
884
885         if (xpc_part_ref(part)) {
886                 ret = xpc_arch_ops.send_payload(&part->channels[ch_number],
887                                   flags, payload, payload_size, 0, NULL, NULL);
888                 xpc_part_deref(part);
889         }
890
891         return ret;
892 }
893
894 /*
895  * Send a message that contains the user's payload on the specified channel
896  * connected to the specified partition.
897  *
898  * NOTE that this routine can sleep waiting for a message entry to become
899  * available. To not sleep, pass in the XPC_NOWAIT flag.
900  *
901  * This routine will not wait for the message to be sent or received.
902  *
903  * Once the remote end of the channel has received the message, the function
904  * passed as an argument to xpc_initiate_send_notify() will be called. This
905  * allows the sender to free up or re-use any buffers referenced by the
906  * message, but does NOT mean the message has been processed at the remote
907  * end by a receiver.
908  *
909  * If this routine returns an error, the caller's function will NOT be called.
910  *
911  * Arguments:
912  *
913  *      partid - ID of partition to which the channel is connected.
914  *      ch_number - channel # to send message on.
915  *      flags - see xp.h for valid flags.
916  *      payload - pointer to the payload which is to be sent.
917  *      payload_size - size of the payload in bytes.
918  *      func - function to call with asynchronous notification of message
919  *                receipt. THIS FUNCTION MUST BE NON-BLOCKING.
920  *      key - user-defined key to be passed to the function when it's called.
921  */
922 enum xp_retval
923 xpc_initiate_send_notify(short partid, int ch_number, u32 flags, void *payload,
924                          u16 payload_size, xpc_notify_func func, void *key)
925 {
926         struct xpc_partition *part = &xpc_partitions[partid];
927         enum xp_retval ret = xpUnknownReason;
928
929         dev_dbg(xpc_chan, "payload=0x%p, partid=%d, channel=%d\n", payload,
930                 partid, ch_number);
931
932         DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
933         DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
934         DBUG_ON(payload == NULL);
935         DBUG_ON(func == NULL);
936
937         if (xpc_part_ref(part)) {
938                 ret = xpc_arch_ops.send_payload(&part->channels[ch_number],
939                           flags, payload, payload_size, XPC_N_CALL, func, key);
940                 xpc_part_deref(part);
941         }
942         return ret;
943 }
944
945 /*
946  * Deliver a message's payload to its intended recipient.
947  */
948 void
949 xpc_deliver_payload(struct xpc_channel *ch)
950 {
951         void *payload;
952
953         payload = xpc_arch_ops.get_deliverable_payload(ch);
954         if (payload != NULL) {
955
956                 /*
957                  * This ref is taken to protect the payload itself from being
958                  * freed before the user is finished with it, which the user
959                  * indicates by calling xpc_initiate_received().
960                  */
961                 xpc_msgqueue_ref(ch);
962
963                 atomic_inc(&ch->kthreads_active);
964
965                 if (ch->func != NULL) {
966                         dev_dbg(xpc_chan, "ch->func() called, payload=0x%p "
967                                 "partid=%d channel=%d\n", payload, ch->partid,
968                                 ch->number);
969
970                         /* deliver the message to its intended recipient */
971                         ch->func(xpMsgReceived, ch->partid, ch->number, payload,
972                                  ch->key);
973
974                         dev_dbg(xpc_chan, "ch->func() returned, payload=0x%p "
975                                 "partid=%d channel=%d\n", payload, ch->partid,
976                                 ch->number);
977                 }
978
979                 atomic_dec(&ch->kthreads_active);
980         }
981 }
982
983 /*
984  * Acknowledge receipt of a delivered message's payload.
985  *
986  * This function, although called by users, does not call xpc_part_ref() to
987  * ensure that the partition infrastructure is in place. It relies on the
988  * fact that we called xpc_msgqueue_ref() in xpc_deliver_payload().
989  *
990  * Arguments:
991  *
992  *      partid - ID of partition to which the channel is connected.
993  *      ch_number - channel # message received on.
994  *      payload - pointer to the payload area allocated via
995  *                      xpc_initiate_send() or xpc_initiate_send_notify().
996  */
997 void
998 xpc_initiate_received(short partid, int ch_number, void *payload)
999 {
1000         struct xpc_partition *part = &xpc_partitions[partid];
1001         struct xpc_channel *ch;
1002
1003         DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
1004         DBUG_ON(ch_number < 0 || ch_number >= part->nchannels);
1005
1006         ch = &part->channels[ch_number];
1007         xpc_arch_ops.received_payload(ch, payload);
1008
1009         /* the call to xpc_msgqueue_ref() was done by xpc_deliver_payload()  */
1010         xpc_msgqueue_deref(ch);
1011 }