1 /*
2 ** -----------------------------------------------------------------------------
3 **
4 **  Perle Specialix driver for Linux
5 **  Ported from existing RIO Driver for SCO sources.
6  *
7  *  (C) 1990 - 2000 Specialix International Ltd., Byfleet, Surrey, UK.
8  *
9  *      This program is free software; you can redistribute it and/or modify
10  *      it under the terms of the GNU General Public License as published by
11  *      the Free Software Foundation; either version 2 of the License, or
12  *      (at your option) any later version.
13  *
14  *      This program is distributed in the hope that it will be useful,
15  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
16  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  *      GNU General Public License for more details.
18  *
19  *      You should have received a copy of the GNU General Public License
20  *      along with this program; if not, write to the Free Software
21  *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 **
23 **	Module		: rioroute.c
24 **	SID		: 1.3
25 **	Last Modified	: 11/6/98 10:33:46
26 **	Retrieved	: 11/6/98 10:33:50
27 **
28 **  ident @(#)rioroute.c	1.3
29 **
30 ** -----------------------------------------------------------------------------
31 */
32 
33 #include <linux/module.h>
34 #include <linux/errno.h>
35 #include <asm/io.h>
36 #include <asm/system.h>
37 #include <asm/string.h>
38 #include <asm/uaccess.h>
39 
40 #include <linux/termios.h>
41 #include <linux/serial.h>
42 
43 #include <linux/generic_serial.h>
44 
45 
46 #include "linux_compat.h"
47 #include "rio_linux.h"
48 #include "pkt.h"
49 #include "daemon.h"
50 #include "rio.h"
51 #include "riospace.h"
52 #include "cmdpkt.h"
53 #include "map.h"
54 #include "rup.h"
55 #include "port.h"
56 #include "riodrvr.h"
57 #include "rioinfo.h"
58 #include "func.h"
59 #include "errors.h"
60 #include "pci.h"
61 
62 #include "parmmap.h"
63 #include "unixrup.h"
64 #include "board.h"
65 #include "host.h"
66 #include "phb.h"
67 #include "link.h"
68 #include "cmdblk.h"
69 #include "route.h"
70 #include "cirrus.h"
71 #include "rioioctl.h"
72 #include "param.h"
73 
74 static int RIOCheckIsolated(struct rio_info *, struct Host *, unsigned int);
75 static int RIOIsolate(struct rio_info *, struct Host *, unsigned int);
76 static int RIOCheck(struct Host *, unsigned int);
77 static void RIOConCon(struct rio_info *, struct Host *, unsigned int, unsigned int, unsigned int, unsigned int, int);
78 
79 
80 /*
81 ** Incoming on the ROUTE_RUP
82 ** I wrote this while I was tired. Forgive me.
83 */
RIORouteRup(struct rio_info * p,unsigned int Rup,struct Host * HostP,struct PKT __iomem * PacketP)84 int RIORouteRup(struct rio_info *p, unsigned int Rup, struct Host *HostP, struct PKT __iomem * PacketP)
85 {
86 	struct PktCmd __iomem *PktCmdP = (struct PktCmd __iomem *) PacketP->data;
87 	struct PktCmd_M *PktReplyP;
88 	struct CmdBlk *CmdBlkP;
89 	struct Port *PortP;
90 	struct Map *MapP;
91 	struct Top *TopP;
92 	int ThisLink, ThisLinkMin, ThisLinkMax;
93 	int port;
94 	int Mod, Mod1, Mod2;
95 	unsigned short RtaType;
96 	unsigned int RtaUniq;
97 	unsigned int ThisUnit, ThisUnit2;	/* 2 ids to accommodate 16 port RTA */
98 	unsigned int OldUnit, NewUnit, OldLink, NewLink;
99 	char *MyType, *MyName;
100 	int Lies;
101 	unsigned long flags;
102 
103 	/*
104 	 ** Is this unit telling us it's current link topology?
105 	 */
106 	if (readb(&PktCmdP->Command) == ROUTE_TOPOLOGY) {
107 		MapP = HostP->Mapping;
108 
109 		/*
110 		 ** The packet can be sent either by the host or by an RTA.
111 		 ** If it comes from the host, then we need to fill in the
112 		 ** Topology array in the host structure. If it came in
113 		 ** from an RTA then we need to fill in the Mapping structure's
114 		 ** Topology array for the unit.
115 		 */
116 		if (Rup >= (unsigned short) MAX_RUP) {
117 			ThisUnit = HOST_ID;
118 			TopP = HostP->Topology;
119 			MyType = "Host";
120 			MyName = HostP->Name;
121 			ThisLinkMin = ThisLinkMax = Rup - MAX_RUP;
122 		} else {
123 			ThisUnit = Rup + 1;
124 			TopP = HostP->Mapping[Rup].Topology;
125 			MyType = "RTA";
126 			MyName = HostP->Mapping[Rup].Name;
127 			ThisLinkMin = 0;
128 			ThisLinkMax = LINKS_PER_UNIT - 1;
129 		}
130 
131 		/*
132 		 ** Lies will not be tolerated.
133 		 ** If any pair of links claim to be connected to the same
134 		 ** place, then ignore this packet completely.
135 		 */
136 		Lies = 0;
137 		for (ThisLink = ThisLinkMin + 1; ThisLink <= ThisLinkMax; ThisLink++) {
138 			/*
139 			 ** it won't lie about network interconnect, total disconnects
140 			 ** and no-IDs. (or at least, it doesn't *matter* if it does)
141 			 */
142 			if (readb(&PktCmdP->RouteTopology[ThisLink].Unit) > (unsigned short) MAX_RUP)
143 				continue;
144 
145 			for (NewLink = ThisLinkMin; NewLink < ThisLink; NewLink++) {
146 				if ((readb(&PktCmdP->RouteTopology[ThisLink].Unit) == readb(&PktCmdP->RouteTopology[NewLink].Unit)) && (readb(&PktCmdP->RouteTopology[ThisLink].Link) == readb(&PktCmdP->RouteTopology[NewLink].Link))) {
147 					Lies++;
148 				}
149 			}
150 		}
151 
152 		if (Lies) {
153 			rio_dprintk(RIO_DEBUG_ROUTE, "LIES! DAMN LIES! %d LIES!\n", Lies);
154 			rio_dprintk(RIO_DEBUG_ROUTE, "%d:%c %d:%c %d:%c %d:%c\n",
155 				    readb(&PktCmdP->RouteTopology[0].Unit),
156 				    'A' + readb(&PktCmdP->RouteTopology[0].Link),
157 				    readb(&PktCmdP->RouteTopology[1].Unit),
158 				    'A' + readb(&PktCmdP->RouteTopology[1].Link), readb(&PktCmdP->RouteTopology[2].Unit), 'A' + readb(&PktCmdP->RouteTopology[2].Link), readb(&PktCmdP->RouteTopology[3].Unit), 'A' + readb(&PktCmdP->RouteTopology[3].Link));
159 			return 1;
160 		}
161 
162 		/*
163 		 ** now, process each link.
164 		 */
165 		for (ThisLink = ThisLinkMin; ThisLink <= ThisLinkMax; ThisLink++) {
166 			/*
167 			 ** this is what it was connected to
168 			 */
169 			OldUnit = TopP[ThisLink].Unit;
170 			OldLink = TopP[ThisLink].Link;
171 
172 			/*
173 			 ** this is what it is now connected to
174 			 */
175 			NewUnit = readb(&PktCmdP->RouteTopology[ThisLink].Unit);
176 			NewLink = readb(&PktCmdP->RouteTopology[ThisLink].Link);
177 
178 			if (OldUnit != NewUnit || OldLink != NewLink) {
179 				/*
180 				 ** something has changed!
181 				 */
182 
183 				if (NewUnit > MAX_RUP && NewUnit != ROUTE_DISCONNECT && NewUnit != ROUTE_NO_ID && NewUnit != ROUTE_INTERCONNECT) {
184 					rio_dprintk(RIO_DEBUG_ROUTE, "I have a link from %s %s to unit %d:%d - I don't like it.\n", MyType, MyName, NewUnit, NewLink);
185 				} else {
186 					/*
187 					 ** put the new values in
188 					 */
189 					TopP[ThisLink].Unit = NewUnit;
190 					TopP[ThisLink].Link = NewLink;
191 
192 					RIOSetChange(p);
193 
194 					if (OldUnit <= MAX_RUP) {
195 						/*
196 						 ** If something has become bust, then re-enable them messages
197 						 */
198 						if (!p->RIONoMessage)
199 							RIOConCon(p, HostP, ThisUnit, ThisLink, OldUnit, OldLink, DISCONNECT);
200 					}
201 
202 					if ((NewUnit <= MAX_RUP) && !p->RIONoMessage)
203 						RIOConCon(p, HostP, ThisUnit, ThisLink, NewUnit, NewLink, CONNECT);
204 
205 					if (NewUnit == ROUTE_NO_ID)
206 						rio_dprintk(RIO_DEBUG_ROUTE, "%s %s (%c) is connected to an unconfigured unit.\n", MyType, MyName, 'A' + ThisLink);
207 
208 					if (NewUnit == ROUTE_INTERCONNECT) {
209 						if (!p->RIONoMessage)
210 							printk(KERN_DEBUG "rio: %s '%s' (%c) is connected to another network.\n", MyType, MyName, 'A' + ThisLink);
211 					}
212 
213 					/*
214 					 ** perform an update for 'the other end', so that these messages
215 					 ** only appears once. Only disconnect the other end if it is pointing
216 					 ** at us!
217 					 */
218 					if (OldUnit == HOST_ID) {
219 						if (HostP->Topology[OldLink].Unit == ThisUnit && HostP->Topology[OldLink].Link == ThisLink) {
220 							rio_dprintk(RIO_DEBUG_ROUTE, "SETTING HOST (%c) TO DISCONNECTED!\n", OldLink + 'A');
221 							HostP->Topology[OldLink].Unit = ROUTE_DISCONNECT;
222 							HostP->Topology[OldLink].Link = NO_LINK;
223 						} else {
224 							rio_dprintk(RIO_DEBUG_ROUTE, "HOST(%c) WAS NOT CONNECTED TO %s (%c)!\n", OldLink + 'A', HostP->Mapping[ThisUnit - 1].Name, ThisLink + 'A');
225 						}
226 					} else if (OldUnit <= MAX_RUP) {
227 						if (HostP->Mapping[OldUnit - 1].Topology[OldLink].Unit == ThisUnit && HostP->Mapping[OldUnit - 1].Topology[OldLink].Link == ThisLink) {
228 							rio_dprintk(RIO_DEBUG_ROUTE, "SETTING RTA %s (%c) TO DISCONNECTED!\n", HostP->Mapping[OldUnit - 1].Name, OldLink + 'A');
229 							HostP->Mapping[OldUnit - 1].Topology[OldLink].Unit = ROUTE_DISCONNECT;
230 							HostP->Mapping[OldUnit - 1].Topology[OldLink].Link = NO_LINK;
231 						} else {
232 							rio_dprintk(RIO_DEBUG_ROUTE, "RTA %s (%c) WAS NOT CONNECTED TO %s (%c)\n", HostP->Mapping[OldUnit - 1].Name, OldLink + 'A', HostP->Mapping[ThisUnit - 1].Name, ThisLink + 'A');
233 						}
234 					}
235 					if (NewUnit == HOST_ID) {
236 						rio_dprintk(RIO_DEBUG_ROUTE, "MARKING HOST (%c) CONNECTED TO %s (%c)\n", NewLink + 'A', MyName, ThisLink + 'A');
237 						HostP->Topology[NewLink].Unit = ThisUnit;
238 						HostP->Topology[NewLink].Link = ThisLink;
239 					} else if (NewUnit <= MAX_RUP) {
240 						rio_dprintk(RIO_DEBUG_ROUTE, "MARKING RTA %s (%c) CONNECTED TO %s (%c)\n", HostP->Mapping[NewUnit - 1].Name, NewLink + 'A', MyName, ThisLink + 'A');
241 						HostP->Mapping[NewUnit - 1].Topology[NewLink].Unit = ThisUnit;
242 						HostP->Mapping[NewUnit - 1].Topology[NewLink].Link = ThisLink;
243 					}
244 				}
245 				RIOSetChange(p);
246 				RIOCheckIsolated(p, HostP, OldUnit);
247 			}
248 		}
249 		return 1;
250 	}
251 
252 	/*
253 	 ** The only other command we recognise is a route_request command
254 	 */
255 	if (readb(&PktCmdP->Command) != ROUTE_REQUEST) {
256 		rio_dprintk(RIO_DEBUG_ROUTE, "Unknown command %d received on rup %d host %p ROUTE_RUP\n", readb(&PktCmdP->Command), Rup, HostP);
257 		return 1;
258 	}
259 
260 	RtaUniq = (readb(&PktCmdP->UniqNum[0])) + (readb(&PktCmdP->UniqNum[1]) << 8) + (readb(&PktCmdP->UniqNum[2]) << 16) + (readb(&PktCmdP->UniqNum[3]) << 24);
261 
262 	/*
263 	 ** Determine if 8 or 16 port RTA
264 	 */
265 	RtaType = GetUnitType(RtaUniq);
266 
267 	rio_dprintk(RIO_DEBUG_ROUTE, "Received a request for an ID for serial number %x\n", RtaUniq);
268 
269 	Mod = readb(&PktCmdP->ModuleTypes);
270 	Mod1 = LONYBLE(Mod);
271 	if (RtaType == TYPE_RTA16) {
272 		/*
273 		 ** Only one ident is set for a 16 port RTA. To make compatible
274 		 ** with 8 port, set 2nd ident in Mod2 to the same as Mod1.
275 		 */
276 		Mod2 = Mod1;
277 		rio_dprintk(RIO_DEBUG_ROUTE, "Backplane type is %s (all ports)\n", p->RIOModuleTypes[Mod1].Name);
278 	} else {
279 		Mod2 = HINYBLE(Mod);
280 		rio_dprintk(RIO_DEBUG_ROUTE, "Module types are %s (ports 0-3) and %s (ports 4-7)\n", p->RIOModuleTypes[Mod1].Name, p->RIOModuleTypes[Mod2].Name);
281 	}
282 
283 	/*
284 	 ** try to unhook a command block from the command free list.
285 	 */
286 	if (!(CmdBlkP = RIOGetCmdBlk())) {
287 		rio_dprintk(RIO_DEBUG_ROUTE, "No command blocks to route RTA! come back later.\n");
288 		return 0;
289 	}
290 
291 	/*
292 	 ** Fill in the default info on the command block
293 	 */
294 	CmdBlkP->Packet.dest_unit = Rup;
295 	CmdBlkP->Packet.dest_port = ROUTE_RUP;
296 	CmdBlkP->Packet.src_unit = HOST_ID;
297 	CmdBlkP->Packet.src_port = ROUTE_RUP;
298 	CmdBlkP->Packet.len = PKT_CMD_BIT | 1;
299 	CmdBlkP->PreFuncP = CmdBlkP->PostFuncP = NULL;
300 	PktReplyP = (struct PktCmd_M *) CmdBlkP->Packet.data;
301 
302 	if (!RIOBootOk(p, HostP, RtaUniq)) {
303 		rio_dprintk(RIO_DEBUG_ROUTE, "RTA %x tried to get an ID, but does not belong - FOAD it!\n", RtaUniq);
304 		PktReplyP->Command = ROUTE_FOAD;
305 		memcpy(PktReplyP->CommandText, "RT_FOAD", 7);
306 		RIOQueueCmdBlk(HostP, Rup, CmdBlkP);
307 		return 1;
308 	}
309 
310 	/*
311 	 ** Check to see if the RTA is configured for this host
312 	 */
313 	for (ThisUnit = 0; ThisUnit < MAX_RUP; ThisUnit++) {
314 		rio_dprintk(RIO_DEBUG_ROUTE, "Entry %d Flags=%s %s UniqueNum=0x%x\n",
315 			    ThisUnit, HostP->Mapping[ThisUnit].Flags & SLOT_IN_USE ? "Slot-In-Use" : "Not In Use", HostP->Mapping[ThisUnit].Flags & SLOT_TENTATIVE ? "Slot-Tentative" : "Not Tentative", HostP->Mapping[ThisUnit].RtaUniqueNum);
316 
317 		/*
318 		 ** We have an entry for it.
319 		 */
320 		if ((HostP->Mapping[ThisUnit].Flags & (SLOT_IN_USE | SLOT_TENTATIVE)) && (HostP->Mapping[ThisUnit].RtaUniqueNum == RtaUniq)) {
321 			if (RtaType == TYPE_RTA16) {
322 				ThisUnit2 = HostP->Mapping[ThisUnit].ID2 - 1;
323 				rio_dprintk(RIO_DEBUG_ROUTE, "Found unit 0x%x at slots %d+%d\n", RtaUniq, ThisUnit, ThisUnit2);
324 			} else
325 				rio_dprintk(RIO_DEBUG_ROUTE, "Found unit 0x%x at slot %d\n", RtaUniq, ThisUnit);
326 			/*
327 			 ** If we have no knowledge of booting it, then the host has
328 			 ** been re-booted, and so we must kill the RTA, so that it
329 			 ** will be booted again (potentially with new bins)
330 			 ** and it will then re-ask for an ID, which we will service.
331 			 */
332 			if ((HostP->Mapping[ThisUnit].Flags & SLOT_IN_USE) && !(HostP->Mapping[ThisUnit].Flags & RTA_BOOTED)) {
333 				if (!(HostP->Mapping[ThisUnit].Flags & MSG_DONE)) {
334 					if (!p->RIONoMessage)
335 						printk(KERN_DEBUG "rio: RTA '%s' is being updated.\n", HostP->Mapping[ThisUnit].Name);
336 					HostP->Mapping[ThisUnit].Flags |= MSG_DONE;
337 				}
338 				PktReplyP->Command = ROUTE_FOAD;
339 				memcpy(PktReplyP->CommandText, "RT_FOAD", 7);
340 				RIOQueueCmdBlk(HostP, Rup, CmdBlkP);
341 				return 1;
342 			}
343 
344 			/*
345 			 ** Send the ID (entry) to this RTA. The ID number is implicit as
346 			 ** the offset into the table. It is worth noting at this stage
347 			 ** that offset zero in the table contains the entries for the
348 			 ** RTA with ID 1!!!!
349 			 */
350 			PktReplyP->Command = ROUTE_ALLOCATE;
351 			PktReplyP->IDNum = ThisUnit + 1;
352 			if (RtaType == TYPE_RTA16) {
353 				if (HostP->Mapping[ThisUnit].Flags & SLOT_IN_USE)
354 					/*
355 					 ** Adjust the phb and tx pkt dest_units for 2nd block of 8
356 					 ** only if the RTA has ports associated (SLOT_IN_USE)
357 					 */
358 					RIOFixPhbs(p, HostP, ThisUnit2);
359 				PktReplyP->IDNum2 = ThisUnit2 + 1;
360 				rio_dprintk(RIO_DEBUG_ROUTE, "RTA '%s' has been allocated IDs %d+%d\n", HostP->Mapping[ThisUnit].Name, PktReplyP->IDNum, PktReplyP->IDNum2);
361 			} else {
362 				PktReplyP->IDNum2 = ROUTE_NO_ID;
363 				rio_dprintk(RIO_DEBUG_ROUTE, "RTA '%s' has been allocated ID %d\n", HostP->Mapping[ThisUnit].Name, PktReplyP->IDNum);
364 			}
365 			memcpy(PktReplyP->CommandText, "RT_ALLOCAT", 10);
366 
367 			RIOQueueCmdBlk(HostP, Rup, CmdBlkP);
368 
369 			/*
370 			 ** If this is a freshly booted RTA, then we need to re-open
371 			 ** the ports, if any where open, so that data may once more
372 			 ** flow around the system!
373 			 */
374 			if ((HostP->Mapping[ThisUnit].Flags & RTA_NEWBOOT) && (HostP->Mapping[ThisUnit].SysPort != NO_PORT)) {
375 				/*
376 				 ** look at the ports associated with this beast and
377 				 ** see if any where open. If they was, then re-open
378 				 ** them, using the info from the tty flags.
379 				 */
380 				for (port = 0; port < PORTS_PER_RTA; port++) {
381 					PortP = p->RIOPortp[port + HostP->Mapping[ThisUnit].SysPort];
382 					if (PortP->State & (RIO_MOPEN | RIO_LOPEN)) {
383 						rio_dprintk(RIO_DEBUG_ROUTE, "Re-opened this port\n");
384 						rio_spin_lock_irqsave(&PortP->portSem, flags);
385 						PortP->MagicFlags |= MAGIC_REBOOT;
386 						rio_spin_unlock_irqrestore(&PortP->portSem, flags);
387 					}
388 				}
389 				if (RtaType == TYPE_RTA16) {
390 					for (port = 0; port < PORTS_PER_RTA; port++) {
391 						PortP = p->RIOPortp[port + HostP->Mapping[ThisUnit2].SysPort];
392 						if (PortP->State & (RIO_MOPEN | RIO_LOPEN)) {
393 							rio_dprintk(RIO_DEBUG_ROUTE, "Re-opened this port\n");
394 							rio_spin_lock_irqsave(&PortP->portSem, flags);
395 							PortP->MagicFlags |= MAGIC_REBOOT;
396 							rio_spin_unlock_irqrestore(&PortP->portSem, flags);
397 						}
398 					}
399 				}
400 			}
401 
402 			/*
403 			 ** keep a copy of the module types!
404 			 */
405 			HostP->UnixRups[ThisUnit].ModTypes = Mod;
406 			if (RtaType == TYPE_RTA16)
407 				HostP->UnixRups[ThisUnit2].ModTypes = Mod;
408 
409 			/*
410 			 ** If either of the modules on this unit is read-only or write-only
411 			 ** or none-xprint, then we need to transfer that info over to the
412 			 ** relevant ports.
413 			 */
414 			if (HostP->Mapping[ThisUnit].SysPort != NO_PORT) {
415 				for (port = 0; port < PORTS_PER_MODULE; port++) {
416 					p->RIOPortp[port + HostP->Mapping[ThisUnit].SysPort]->Config &= ~RIO_NOMASK;
417 					p->RIOPortp[port + HostP->Mapping[ThisUnit].SysPort]->Config |= p->RIOModuleTypes[Mod1].Flags[port];
418 					p->RIOPortp[port + PORTS_PER_MODULE + HostP->Mapping[ThisUnit].SysPort]->Config &= ~RIO_NOMASK;
419 					p->RIOPortp[port + PORTS_PER_MODULE + HostP->Mapping[ThisUnit].SysPort]->Config |= p->RIOModuleTypes[Mod2].Flags[port];
420 				}
421 				if (RtaType == TYPE_RTA16) {
422 					for (port = 0; port < PORTS_PER_MODULE; port++) {
423 						p->RIOPortp[port + HostP->Mapping[ThisUnit2].SysPort]->Config &= ~RIO_NOMASK;
424 						p->RIOPortp[port + HostP->Mapping[ThisUnit2].SysPort]->Config |= p->RIOModuleTypes[Mod1].Flags[port];
425 						p->RIOPortp[port + PORTS_PER_MODULE + HostP->Mapping[ThisUnit2].SysPort]->Config &= ~RIO_NOMASK;
426 						p->RIOPortp[port + PORTS_PER_MODULE + HostP->Mapping[ThisUnit2].SysPort]->Config |= p->RIOModuleTypes[Mod2].Flags[port];
427 					}
428 				}
429 			}
430 
431 			/*
432 			 ** Job done, get on with the interrupts!
433 			 */
434 			return 1;
435 		}
436 	}
437 	/*
438 	 ** There is no table entry for this RTA at all.
439 	 **
440 	 ** Lets check to see if we actually booted this unit - if not,
441 	 ** then we reset it and it will go round the loop of being booted
442 	 ** we can then worry about trying to fit it into the table.
443 	 */
444 	for (ThisUnit = 0; ThisUnit < HostP->NumExtraBooted; ThisUnit++)
445 		if (HostP->ExtraUnits[ThisUnit] == RtaUniq)
446 			break;
447 	if (ThisUnit == HostP->NumExtraBooted && ThisUnit != MAX_EXTRA_UNITS) {
448 		/*
449 		 ** if the unit wasn't in the table, and the table wasn't full, then
450 		 ** we reset the unit, because we didn't boot it.
451 		 ** However, if the table is full, it could be that we did boot
452 		 ** this unit, and so we won't reboot it, because it isn't really
453 		 ** all that disastrous to keep the old bins in most cases. This
454 		 ** is a rather tacky feature, but we are on the edge of reallity
455 		 ** here, because the implication is that someone has connected
456 		 ** 16+MAX_EXTRA_UNITS onto one host.
457 		 */
458 		static int UnknownMesgDone = 0;
459 
460 		if (!UnknownMesgDone) {
461 			if (!p->RIONoMessage)
462 				printk(KERN_DEBUG "rio: One or more unknown RTAs are being updated.\n");
463 			UnknownMesgDone = 1;
464 		}
465 
466 		PktReplyP->Command = ROUTE_FOAD;
467 		memcpy(PktReplyP->CommandText, "RT_FOAD", 7);
468 	} else {
469 		/*
470 		 ** we did boot it (as an extra), and there may now be a table
471 		 ** slot free (because of a delete), so we will try to make
472 		 ** a tentative entry for it, so that the configurator can see it
473 		 ** and fill in the details for us.
474 		 */
475 		if (RtaType == TYPE_RTA16) {
476 			if (RIOFindFreeID(p, HostP, &ThisUnit, &ThisUnit2) == 0) {
477 				RIODefaultName(p, HostP, ThisUnit);
478 				rio_fill_host_slot(ThisUnit, ThisUnit2, RtaUniq, HostP);
479 			}
480 		} else {
481 			if (RIOFindFreeID(p, HostP, &ThisUnit, NULL) == 0) {
482 				RIODefaultName(p, HostP, ThisUnit);
483 				rio_fill_host_slot(ThisUnit, 0, RtaUniq, HostP);
484 			}
485 		}
486 		PktReplyP->Command = ROUTE_USED;
487 		memcpy(PktReplyP->CommandText, "RT_USED", 7);
488 	}
489 	RIOQueueCmdBlk(HostP, Rup, CmdBlkP);
490 	return 1;
491 }
492 
493 
RIOFixPhbs(struct rio_info * p,struct Host * HostP,unsigned int unit)494 void RIOFixPhbs(struct rio_info *p, struct Host *HostP, unsigned int unit)
495 {
496 	unsigned short link, port;
497 	struct Port *PortP;
498 	unsigned long flags;
499 	int PortN = HostP->Mapping[unit].SysPort;
500 
501 	rio_dprintk(RIO_DEBUG_ROUTE, "RIOFixPhbs unit %d sysport %d\n", unit, PortN);
502 
503 	if (PortN != -1) {
504 		unsigned short dest_unit = HostP->Mapping[unit].ID2;
505 
506 		/*
507 		 ** Get the link number used for the 1st 8 phbs on this unit.
508 		 */
509 		PortP = p->RIOPortp[HostP->Mapping[dest_unit - 1].SysPort];
510 
511 		link = readw(&PortP->PhbP->link);
512 
513 		for (port = 0; port < PORTS_PER_RTA; port++, PortN++) {
514 			unsigned short dest_port = port + 8;
515 			u16 __iomem *TxPktP;
516 			struct PKT __iomem *Pkt;
517 
518 			PortP = p->RIOPortp[PortN];
519 
520 			rio_spin_lock_irqsave(&PortP->portSem, flags);
521 			/*
522 			 ** If RTA is not powered on, the tx packets will be
523 			 ** unset, so go no further.
524 			 */
525 			if (!PortP->TxStart) {
526 				rio_dprintk(RIO_DEBUG_ROUTE, "Tx pkts not set up yet\n");
527 				rio_spin_unlock_irqrestore(&PortP->portSem, flags);
528 				break;
529 			}
530 
531 			/*
532 			 ** For the second slot of a 16 port RTA, the driver needs to
533 			 ** sort out the phb to port mappings. The dest_unit for this
534 			 ** group of 8 phbs is set to the dest_unit of the accompanying
535 			 ** 8 port block. The dest_port of the second unit is set to
536 			 ** be in the range 8-15 (i.e. 8 is added). Thus, for a 16 port
537 			 ** RTA with IDs 5 and 6, traffic bound for port 6 of unit 6
538 			 ** (being the second map ID) will be sent to dest_unit 5, port
539 			 ** 14. When this RTA is deleted, dest_unit for ID 6 will be
540 			 ** restored, and the dest_port will be reduced by 8.
541 			 ** Transmit packets also have a destination field which needs
542 			 ** adjusting in the same manner.
543 			 ** Note that the unit/port bytes in 'dest' are swapped.
544 			 ** We also need to adjust the phb and rup link numbers for the
545 			 ** second block of 8 ttys.
546 			 */
547 			for (TxPktP = PortP->TxStart; TxPktP <= PortP->TxEnd; TxPktP++) {
548 				/*
549 				 ** *TxPktP is the pointer to the transmit packet on the host
550 				 ** card. This needs to be translated into a 32 bit pointer
551 				 ** so it can be accessed from the driver.
552 				 */
553 				Pkt = (struct PKT __iomem *) RIO_PTR(HostP->Caddr, readw(TxPktP));
554 
555 				/*
556 				 ** If the packet is used, reset it.
557 				 */
558 				Pkt = (struct PKT __iomem *) ((unsigned long) Pkt & ~PKT_IN_USE);
559 				writeb(dest_unit, &Pkt->dest_unit);
560 				writeb(dest_port, &Pkt->dest_port);
561 			}
562 			rio_dprintk(RIO_DEBUG_ROUTE, "phb dest: Old %x:%x New %x:%x\n", readw(&PortP->PhbP->destination) & 0xff, (readw(&PortP->PhbP->destination) >> 8) & 0xff, dest_unit, dest_port);
563 			writew(dest_unit + (dest_port << 8), &PortP->PhbP->destination);
564 			writew(link, &PortP->PhbP->link);
565 
566 			rio_spin_unlock_irqrestore(&PortP->portSem, flags);
567 		}
568 		/*
569 		 ** Now make sure the range of ports to be serviced includes
570 		 ** the 2nd 8 on this 16 port RTA.
571 		 */
572 		if (link > 3)
573 			return;
574 		if (((unit * 8) + 7) > readw(&HostP->LinkStrP[link].last_port)) {
575 			rio_dprintk(RIO_DEBUG_ROUTE, "last port on host link %d: %d\n", link, (unit * 8) + 7);
576 			writew((unit * 8) + 7, &HostP->LinkStrP[link].last_port);
577 		}
578 	}
579 }
580 
581 /*
582 ** Check to see if the new disconnection has isolated this unit.
583 ** If it has, then invalidate all its link information, and tell
584 ** the world about it. This is done to ensure that the configurator
585 ** only gets up-to-date information about what is going on.
586 */
RIOCheckIsolated(struct rio_info * p,struct Host * HostP,unsigned int UnitId)587 static int RIOCheckIsolated(struct rio_info *p, struct Host *HostP, unsigned int UnitId)
588 {
589 	unsigned long flags;
590 	rio_spin_lock_irqsave(&HostP->HostLock, flags);
591 
592 	if (RIOCheck(HostP, UnitId)) {
593 		rio_dprintk(RIO_DEBUG_ROUTE, "Unit %d is NOT isolated\n", UnitId);
594 		rio_spin_unlock_irqrestore(&HostP->HostLock, flags);
595 		return (0);
596 	}
597 
598 	RIOIsolate(p, HostP, UnitId);
599 	RIOSetChange(p);
600 	rio_spin_unlock_irqrestore(&HostP->HostLock, flags);
601 	return 1;
602 }
603 
604 /*
605 ** Invalidate all the link interconnectivity of this unit, and of
606 ** all the units attached to it. This will mean that the entire
607 ** subnet will re-introduce itself.
608 */
RIOIsolate(struct rio_info * p,struct Host * HostP,unsigned int UnitId)609 static int RIOIsolate(struct rio_info *p, struct Host *HostP, unsigned int UnitId)
610 {
611 	unsigned int link, unit;
612 
613 	UnitId--;		/* this trick relies on the Unit Id being UNSIGNED! */
614 
615 	if (UnitId >= MAX_RUP)	/* dontcha just lurv unsigned maths! */
616 		return (0);
617 
618 	if (HostP->Mapping[UnitId].Flags & BEEN_HERE)
619 		return (0);
620 
621 	HostP->Mapping[UnitId].Flags |= BEEN_HERE;
622 
623 	if (p->RIOPrintDisabled == DO_PRINT)
624 		rio_dprintk(RIO_DEBUG_ROUTE, "RIOMesgIsolated %s", HostP->Mapping[UnitId].Name);
625 
626 	for (link = 0; link < LINKS_PER_UNIT; link++) {
627 		unit = HostP->Mapping[UnitId].Topology[link].Unit;
628 		HostP->Mapping[UnitId].Topology[link].Unit = ROUTE_DISCONNECT;
629 		HostP->Mapping[UnitId].Topology[link].Link = NO_LINK;
630 		RIOIsolate(p, HostP, unit);
631 	}
632 	HostP->Mapping[UnitId].Flags &= ~BEEN_HERE;
633 	return 1;
634 }
635 
RIOCheck(struct Host * HostP,unsigned int UnitId)636 static int RIOCheck(struct Host *HostP, unsigned int UnitId)
637 {
638 	unsigned char link;
639 
640 /* 	rio_dprint(RIO_DEBUG_ROUTE, ("Check to see if unit %d has a route to the host\n",UnitId)); */
641 	rio_dprintk(RIO_DEBUG_ROUTE, "RIOCheck : UnitID = %d\n", UnitId);
642 
643 	if (UnitId == HOST_ID) {
644 		/* rio_dprint(RIO_DEBUG_ROUTE, ("Unit %d is NOT isolated - it IS the host!\n", UnitId)); */
645 		return 1;
646 	}
647 
648 	UnitId--;
649 
650 	if (UnitId >= MAX_RUP) {
651 		/* rio_dprint(RIO_DEBUG_ROUTE, ("Unit %d - ignored.\n", UnitId)); */
652 		return 0;
653 	}
654 
655 	for (link = 0; link < LINKS_PER_UNIT; link++) {
656 		if (HostP->Mapping[UnitId].Topology[link].Unit == HOST_ID) {
657 			/* rio_dprint(RIO_DEBUG_ROUTE, ("Unit %d is connected directly to host via link (%c).\n",
658 			   UnitId, 'A'+link)); */
659 			return 1;
660 		}
661 	}
662 
663 	if (HostP->Mapping[UnitId].Flags & BEEN_HERE) {
664 		/* rio_dprint(RIO_DEBUG_ROUTE, ("Been to Unit %d before - ignoring\n", UnitId)); */
665 		return 0;
666 	}
667 
668 	HostP->Mapping[UnitId].Flags |= BEEN_HERE;
669 
670 	for (link = 0; link < LINKS_PER_UNIT; link++) {
671 		/* rio_dprint(RIO_DEBUG_ROUTE, ("Unit %d check link (%c)\n", UnitId,'A'+link)); */
672 		if (RIOCheck(HostP, HostP->Mapping[UnitId].Topology[link].Unit)) {
673 			/* rio_dprint(RIO_DEBUG_ROUTE, ("Unit %d is connected to something that knows the host via link (%c)\n", UnitId,link+'A')); */
674 			HostP->Mapping[UnitId].Flags &= ~BEEN_HERE;
675 			return 1;
676 		}
677 	}
678 
679 	HostP->Mapping[UnitId].Flags &= ~BEEN_HERE;
680 
681 	/* rio_dprint(RIO_DEBUG_ROUTE, ("Unit %d DOESN'T KNOW THE HOST!\n", UnitId)); */
682 
683 	return 0;
684 }
685 
686 /*
687 ** Returns the type of unit (host, 16/8 port RTA)
688 */
689 
GetUnitType(unsigned int Uniq)690 unsigned int GetUnitType(unsigned int Uniq)
691 {
692 	switch ((Uniq >> 28) & 0xf) {
693 	case RIO_AT:
694 	case RIO_MCA:
695 	case RIO_EISA:
696 	case RIO_PCI:
697 		rio_dprintk(RIO_DEBUG_ROUTE, "Unit type: Host\n");
698 		return (TYPE_HOST);
699 	case RIO_RTA_16:
700 		rio_dprintk(RIO_DEBUG_ROUTE, "Unit type: 16 port RTA\n");
701 		return (TYPE_RTA16);
702 	case RIO_RTA:
703 		rio_dprintk(RIO_DEBUG_ROUTE, "Unit type: 8 port RTA\n");
704 		return (TYPE_RTA8);
705 	default:
706 		rio_dprintk(RIO_DEBUG_ROUTE, "Unit type: Unrecognised\n");
707 		return (99);
708 	}
709 }
710 
RIOSetChange(struct rio_info * p)711 int RIOSetChange(struct rio_info *p)
712 {
713 	if (p->RIOQuickCheck != NOT_CHANGED)
714 		return (0);
715 	p->RIOQuickCheck = CHANGED;
716 	if (p->RIOSignalProcess) {
717 		rio_dprintk(RIO_DEBUG_ROUTE, "Send SIG-HUP");
718 		/*
719 		   psignal( RIOSignalProcess, SIGHUP );
720 		 */
721 	}
722 	return (0);
723 }
724 
RIOConCon(struct rio_info * p,struct Host * HostP,unsigned int FromId,unsigned int FromLink,unsigned int ToId,unsigned int ToLink,int Change)725 static void RIOConCon(struct rio_info *p,
726 		      struct Host *HostP,
727 		      unsigned int FromId,
728 		      unsigned int FromLink,
729 		      unsigned int ToId,
730 		      unsigned int ToLink,
731 		      int Change)
732 {
733 	char *FromName;
734 	char *FromType;
735 	char *ToName;
736 	char *ToType;
737 	unsigned int tp;
738 
739 /*
740 ** 15.10.1998 ARG - ESIL 0759
741 ** (Part) fix for port being trashed when opened whilst RTA "disconnected"
742 **
743 ** What's this doing in here anyway ?
744 ** It was causing the port to be 'unmapped' if opened whilst RTA "disconnected"
745 **
746 ** 09.12.1998 ARG - ESIL 0776 - part fix
747 ** Okay, We've found out what this was all about now !
748 ** Someone had botched this to use RIOHalted to indicated the number of RTAs
749 ** 'disconnected'. The value in RIOHalted was then being used in the
750 ** 'RIO_QUICK_CHECK' ioctl. A none zero value indicating that a least one RTA
751 ** is 'disconnected'. The change was put in to satisfy a customer's needs.
752 ** Having taken this bit of code out 'RIO_QUICK_CHECK' now no longer works for
753 ** the customer.
754 **
755     if (Change == CONNECT) {
756 		if (p->RIOHalted) p->RIOHalted --;
757 	 }
758 	 else {
759 		p->RIOHalted ++;
760 	 }
761 **
762 ** So - we need to implement it slightly differently - a new member of the
763 ** rio_info struct - RIORtaDisCons (RIO RTA connections) keeps track of RTA
764 ** connections and disconnections.
765 */
766 	if (Change == CONNECT) {
767 		if (p->RIORtaDisCons)
768 			p->RIORtaDisCons--;
769 	} else {
770 		p->RIORtaDisCons++;
771 	}
772 
773 	if (p->RIOPrintDisabled == DONT_PRINT)
774 		return;
775 
776 	if (FromId > ToId) {
777 		tp = FromId;
778 		FromId = ToId;
779 		ToId = tp;
780 		tp = FromLink;
781 		FromLink = ToLink;
782 		ToLink = tp;
783 	}
784 
785 	FromName = FromId ? HostP->Mapping[FromId - 1].Name : HostP->Name;
786 	FromType = FromId ? "RTA" : "HOST";
787 	ToName = ToId ? HostP->Mapping[ToId - 1].Name : HostP->Name;
788 	ToType = ToId ? "RTA" : "HOST";
789 
790 	rio_dprintk(RIO_DEBUG_ROUTE, "Link between %s '%s' (%c) and %s '%s' (%c) %s.\n", FromType, FromName, 'A' + FromLink, ToType, ToName, 'A' + ToLink, (Change == CONNECT) ? "established" : "disconnected");
791 	printk(KERN_DEBUG "rio: Link between %s '%s' (%c) and %s '%s' (%c) %s.\n", FromType, FromName, 'A' + FromLink, ToType, ToName, 'A' + ToLink, (Change == CONNECT) ? "established" : "disconnected");
792 }
793 
794 /*
795 ** RIORemoveFromSavedTable :
796 **
797 ** Delete and RTA entry from the saved table given to us
798 ** by the configuration program.
799 */
RIORemoveFromSavedTable(struct rio_info * p,struct Map * pMap)800 static int RIORemoveFromSavedTable(struct rio_info *p, struct Map *pMap)
801 {
802 	int entry;
803 
804 	/*
805 	 ** We loop for all entries even after finding an entry and
806 	 ** zeroing it because we may have two entries to delete if
807 	 ** it's a 16 port RTA.
808 	 */
809 	for (entry = 0; entry < TOTAL_MAP_ENTRIES; entry++) {
810 		if (p->RIOSavedTable[entry].RtaUniqueNum == pMap->RtaUniqueNum) {
811 			memset(&p->RIOSavedTable[entry], 0, sizeof(struct Map));
812 		}
813 	}
814 	return 0;
815 }
816 
817 
818 /*
819 ** RIOCheckDisconnected :
820 **
821 ** Scan the unit links to and return zero if the unit is completely
822 ** disconnected.
823 */
RIOFreeDisconnected(struct rio_info * p,struct Host * HostP,int unit)824 static int RIOFreeDisconnected(struct rio_info *p, struct Host *HostP, int unit)
825 {
826 	int link;
827 
828 
829 	rio_dprintk(RIO_DEBUG_ROUTE, "RIOFreeDisconnect unit %d\n", unit);
830 	/*
831 	 ** If the slot is tentative and does not belong to the
832 	 ** second half of a 16 port RTA then scan to see if
833 	 ** is disconnected.
834 	 */
835 	for (link = 0; link < LINKS_PER_UNIT; link++) {
836 		if (HostP->Mapping[unit].Topology[link].Unit != ROUTE_DISCONNECT)
837 			break;
838 	}
839 
840 	/*
841 	 ** If not all links are disconnected then we can forget about it.
842 	 */
843 	if (link < LINKS_PER_UNIT)
844 		return 1;
845 
846 #ifdef NEED_TO_FIX_THIS
847 	/* Ok so all the links are disconnected. But we may have only just
848 	 ** made this slot tentative and not yet received a topology update.
849 	 ** Lets check how long ago we made it tentative.
850 	 */
851 	rio_dprintk(RIO_DEBUG_ROUTE, "Just about to check LBOLT on entry %d\n", unit);
852 	if (drv_getparm(LBOLT, (ulong_t *) & current_time))
853 		rio_dprintk(RIO_DEBUG_ROUTE, "drv_getparm(LBOLT,....) Failed.\n");
854 
855 	elapse_time = current_time - TentTime[unit];
856 	rio_dprintk(RIO_DEBUG_ROUTE, "elapse %d = current %d - tent %d (%d usec)\n", elapse_time, current_time, TentTime[unit], drv_hztousec(elapse_time));
857 	if (drv_hztousec(elapse_time) < WAIT_TO_FINISH) {
858 		rio_dprintk(RIO_DEBUG_ROUTE, "Skipping slot %d, not timed out yet %d\n", unit, drv_hztousec(elapse_time));
859 		return 1;
860 	}
861 #endif
862 
863 	/*
864 	 ** We have found an usable slot.
865 	 ** If it is half of a 16 port RTA then delete the other half.
866 	 */
867 	if (HostP->Mapping[unit].ID2 != 0) {
868 		int nOther = (HostP->Mapping[unit].ID2) - 1;
869 
870 		rio_dprintk(RIO_DEBUG_ROUTE, "RioFreedis second slot %d.\n", nOther);
871 		memset(&HostP->Mapping[nOther], 0, sizeof(struct Map));
872 	}
873 	RIORemoveFromSavedTable(p, &HostP->Mapping[unit]);
874 
875 	return 0;
876 }
877 
878 
879 /*
880 ** RIOFindFreeID :
881 **
882 ** This function scans the given host table for either one
883 ** or two free unit ID's.
884 */
885 
RIOFindFreeID(struct rio_info * p,struct Host * HostP,unsigned int * pID1,unsigned int * pID2)886 int RIOFindFreeID(struct rio_info *p, struct Host *HostP, unsigned int * pID1, unsigned int * pID2)
887 {
888 	int unit, tempID;
889 
890 	/*
891 	 ** Initialise the ID's to MAX_RUP.
892 	 ** We do this to make the loop for setting the ID's as simple as
893 	 ** possible.
894 	 */
895 	*pID1 = MAX_RUP;
896 	if (pID2 != NULL)
897 		*pID2 = MAX_RUP;
898 
899 	/*
900 	 ** Scan all entries of the host mapping table for free slots.
901 	 ** We scan for free slots first and then if that is not successful
902 	 ** we start all over again looking for tentative slots we can re-use.
903 	 */
904 	for (unit = 0; unit < MAX_RUP; unit++) {
905 		rio_dprintk(RIO_DEBUG_ROUTE, "Scanning unit %d\n", unit);
906 		/*
907 		 ** If the flags are zero then the slot is empty.
908 		 */
909 		if (HostP->Mapping[unit].Flags == 0) {
910 			rio_dprintk(RIO_DEBUG_ROUTE, "      This slot is empty.\n");
911 			/*
912 			 ** If we haven't allocated the first ID then do it now.
913 			 */
914 			if (*pID1 == MAX_RUP) {
915 				rio_dprintk(RIO_DEBUG_ROUTE, "Make tentative entry for first unit %d\n", unit);
916 				*pID1 = unit;
917 
918 				/*
919 				 ** If the second ID is not needed then we can return
920 				 ** now.
921 				 */
922 				if (pID2 == NULL)
923 					return 0;
924 			} else {
925 				/*
926 				 ** Allocate the second slot and return.
927 				 */
928 				rio_dprintk(RIO_DEBUG_ROUTE, "Make tentative entry for second unit %d\n", unit);
929 				*pID2 = unit;
930 				return 0;
931 			}
932 		}
933 	}
934 
935 	/*
936 	 ** If we manage to come out of the free slot loop then we
937 	 ** need to start all over again looking for tentative slots
938 	 ** that we can re-use.
939 	 */
940 	rio_dprintk(RIO_DEBUG_ROUTE, "Starting to scan for tentative slots\n");
941 	for (unit = 0; unit < MAX_RUP; unit++) {
942 		if (((HostP->Mapping[unit].Flags & SLOT_TENTATIVE) || (HostP->Mapping[unit].Flags == 0)) && !(HostP->Mapping[unit].Flags & RTA16_SECOND_SLOT)) {
943 			rio_dprintk(RIO_DEBUG_ROUTE, "    Slot %d looks promising.\n", unit);
944 
945 			if (unit == *pID1) {
946 				rio_dprintk(RIO_DEBUG_ROUTE, "    No it isn't, its the 1st half\n");
947 				continue;
948 			}
949 
950 			/*
951 			 ** Slot is Tentative or Empty, but not a tentative second
952 			 ** slot of a 16 porter.
953 			 ** Attempt to free up this slot (and its parnter if
954 			 ** it is a 16 port slot. The second slot will become
955 			 ** empty after a call to RIOFreeDisconnected so thats why
956 			 ** we look for empty slots above  as well).
957 			 */
958 			if (HostP->Mapping[unit].Flags != 0)
959 				if (RIOFreeDisconnected(p, HostP, unit) != 0)
960 					continue;
961 			/*
962 			 ** If we haven't allocated the first ID then do it now.
963 			 */
964 			if (*pID1 == MAX_RUP) {
965 				rio_dprintk(RIO_DEBUG_ROUTE, "Grab tentative entry for first unit %d\n", unit);
966 				*pID1 = unit;
967 
968 				/*
969 				 ** Clear out this slot now that we intend to use it.
970 				 */
971 				memset(&HostP->Mapping[unit], 0, sizeof(struct Map));
972 
973 				/*
974 				 ** If the second ID is not needed then we can return
975 				 ** now.
976 				 */
977 				if (pID2 == NULL)
978 					return 0;
979 			} else {
980 				/*
981 				 ** Allocate the second slot and return.
982 				 */
983 				rio_dprintk(RIO_DEBUG_ROUTE, "Grab tentative/empty  entry for second unit %d\n", unit);
984 				*pID2 = unit;
985 
986 				/*
987 				 ** Clear out this slot now that we intend to use it.
988 				 */
989 				memset(&HostP->Mapping[unit], 0, sizeof(struct Map));
990 
991 				/* At this point under the right(wrong?) conditions
992 				 ** we may have a first unit ID being higher than the
993 				 ** second unit ID. This is a bad idea if we are about
994 				 ** to fill the slots with a 16 port RTA.
995 				 ** Better check and swap them over.
996 				 */
997 
998 				if (*pID1 > *pID2) {
999 					rio_dprintk(RIO_DEBUG_ROUTE, "Swapping IDS %d %d\n", *pID1, *pID2);
1000 					tempID = *pID1;
1001 					*pID1 = *pID2;
1002 					*pID2 = tempID;
1003 				}
1004 				return 0;
1005 			}
1006 		}
1007 	}
1008 
1009 	/*
1010 	 ** If we manage to get to the end of the second loop then we
1011 	 ** can give up and return a failure.
1012 	 */
1013 	return 1;
1014 }
1015 
1016 
1017 /*
1018 ** The link switch scenario.
1019 **
1020 ** Rta Wun (A) is connected to Tuw (A).
1021 ** The tables are all up to date, and the system is OK.
1022 **
1023 ** If Wun (A) is now moved to Wun (B) before Wun (A) can
1024 ** become disconnected, then the follow happens:
1025 **
1026 ** Tuw (A) spots the change of unit:link at the other end
1027 ** of its link and Tuw sends a topology packet reflecting
1028 ** the change: Tuw (A) now disconnected from Wun (A), and
1029 ** this is closely followed by a packet indicating that
1030 ** Tuw (A) is now connected to Wun (B).
1031 **
1032 ** Wun (B) will spot that it has now become connected, and
1033 ** Wun will send a topology packet, which indicates that
1034 ** both Wun (A) and Wun (B) is connected to Tuw (A).
1035 **
1036 ** Eventually Wun (A) realises that it is now disconnected
1037 ** and Wun will send out a topology packet indicating that
1038 ** Wun (A) is now disconnected.
1039 */
1040