1 /*
2  * Incremental bus scan, based on bus topology
3  *
4  * Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software Foundation,
18  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19  */
20 
21 #include <linux/bug.h>
22 #include <linux/errno.h>
23 #include <linux/firewire.h>
24 #include <linux/firewire-constants.h>
25 #include <linux/jiffies.h>
26 #include <linux/kernel.h>
27 #include <linux/list.h>
28 #include <linux/module.h>
29 #include <linux/slab.h>
30 #include <linux/spinlock.h>
31 
32 #include <asm/atomic.h>
33 #include <asm/byteorder.h>
34 #include <asm/system.h>
35 
36 #include "core.h"
37 
38 #define SELF_ID_PHY_ID(q)		(((q) >> 24) & 0x3f)
39 #define SELF_ID_EXTENDED(q)		(((q) >> 23) & 0x01)
40 #define SELF_ID_LINK_ON(q)		(((q) >> 22) & 0x01)
41 #define SELF_ID_GAP_COUNT(q)		(((q) >> 16) & 0x3f)
42 #define SELF_ID_PHY_SPEED(q)		(((q) >> 14) & 0x03)
43 #define SELF_ID_CONTENDER(q)		(((q) >> 11) & 0x01)
44 #define SELF_ID_PHY_INITIATOR(q)	(((q) >>  1) & 0x01)
45 #define SELF_ID_MORE_PACKETS(q)		(((q) >>  0) & 0x01)
46 
47 #define SELF_ID_EXT_SEQUENCE(q)		(((q) >> 20) & 0x07)
48 
49 #define SELFID_PORT_CHILD	0x3
50 #define SELFID_PORT_PARENT	0x2
51 #define SELFID_PORT_NCONN	0x1
52 #define SELFID_PORT_NONE	0x0
53 
54 static u32 *count_ports(u32 *sid, int *total_port_count, int *child_port_count)
55 {
56 	u32 q;
57 	int port_type, shift, seq;
58 
59 	*total_port_count = 0;
60 	*child_port_count = 0;
61 
62 	shift = 6;
63 	q = *sid;
64 	seq = 0;
65 
66 	while (1) {
67 		port_type = (q >> shift) & 0x03;
68 		switch (port_type) {
69 		case SELFID_PORT_CHILD:
70 			(*child_port_count)++;
71 		case SELFID_PORT_PARENT:
72 		case SELFID_PORT_NCONN:
73 			(*total_port_count)++;
74 		case SELFID_PORT_NONE:
75 			break;
76 		}
77 
78 		shift -= 2;
79 		if (shift == 0) {
80 			if (!SELF_ID_MORE_PACKETS(q))
81 				return sid + 1;
82 
83 			shift = 16;
84 			sid++;
85 			q = *sid;
86 
87 			/*
88 			 * Check that the extra packets actually are
89 			 * extended self ID packets and that the
90 			 * sequence numbers in the extended self ID
91 			 * packets increase as expected.
92 			 */
93 
94 			if (!SELF_ID_EXTENDED(q) ||
95 			    seq != SELF_ID_EXT_SEQUENCE(q))
96 				return NULL;
97 
98 			seq++;
99 		}
100 	}
101 }
102 
103 static int get_port_type(u32 *sid, int port_index)
104 {
105 	int index, shift;
106 
107 	index = (port_index + 5) / 8;
108 	shift = 16 - ((port_index + 5) & 7) * 2;
109 	return (sid[index] >> shift) & 0x03;
110 }
111 
112 static struct fw_node *fw_node_create(u32 sid, int port_count, int color)
113 {
114 	struct fw_node *node;
115 
116 	node = kzalloc(sizeof(*node) + port_count * sizeof(node->ports[0]),
117 		       GFP_ATOMIC);
118 	if (node == NULL)
119 		return NULL;
120 
121 	node->color = color;
122 	node->node_id = LOCAL_BUS | SELF_ID_PHY_ID(sid);
123 	node->link_on = SELF_ID_LINK_ON(sid);
124 	node->phy_speed = SELF_ID_PHY_SPEED(sid);
125 	node->initiated_reset = SELF_ID_PHY_INITIATOR(sid);
126 	node->port_count = port_count;
127 
128 	atomic_set(&node->ref_count, 1);
129 	INIT_LIST_HEAD(&node->link);
130 
131 	return node;
132 }
133 
134 /*
135  * Compute the maximum hop count for this node and it's children.  The
136  * maximum hop count is the maximum number of connections between any
137  * two nodes in the subtree rooted at this node.  We need this for
138  * setting the gap count.  As we build the tree bottom up in
139  * build_tree() below, this is fairly easy to do: for each node we
140  * maintain the max hop count and the max depth, ie the number of hops
141  * to the furthest leaf.  Computing the max hop count breaks down into
142  * two cases: either the path goes through this node, in which case
143  * the hop count is the sum of the two biggest child depths plus 2.
144  * Or it could be the case that the max hop path is entirely
145  * containted in a child tree, in which case the max hop count is just
146  * the max hop count of this child.
147  */
148 static void update_hop_count(struct fw_node *node)
149 {
150 	int depths[2] = { -1, -1 };
151 	int max_child_hops = 0;
152 	int i;
153 
154 	for (i = 0; i < node->port_count; i++) {
155 		if (node->ports[i] == NULL)
156 			continue;
157 
158 		if (node->ports[i]->max_hops > max_child_hops)
159 			max_child_hops = node->ports[i]->max_hops;
160 
161 		if (node->ports[i]->max_depth > depths[0]) {
162 			depths[1] = depths[0];
163 			depths[0] = node->ports[i]->max_depth;
164 		} else if (node->ports[i]->max_depth > depths[1])
165 			depths[1] = node->ports[i]->max_depth;
166 	}
167 
168 	node->max_depth = depths[0] + 1;
169 	node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2);
170 }
171 
172 static inline struct fw_node *fw_node(struct list_head *l)
173 {
174 	return list_entry(l, struct fw_node, link);
175 }
176 
177 /*
178  * This function builds the tree representation of the topology given
179  * by the self IDs from the latest bus reset.  During the construction
180  * of the tree, the function checks that the self IDs are valid and
181  * internally consistent.  On success this function returns the
182  * fw_node corresponding to the local card otherwise NULL.
183  */
184 static struct fw_node *build_tree(struct fw_card *card,
185 				  u32 *sid, int self_id_count)
186 {
187 	struct fw_node *node, *child, *local_node, *irm_node;
188 	struct list_head stack, *h;
189 	u32 *next_sid, *end, q;
190 	int i, port_count, child_port_count, phy_id, parent_count, stack_depth;
191 	int gap_count;
192 	bool beta_repeaters_present;
193 
194 	local_node = NULL;
195 	node = NULL;
196 	INIT_LIST_HEAD(&stack);
197 	stack_depth = 0;
198 	end = sid + self_id_count;
199 	phy_id = 0;
200 	irm_node = NULL;
201 	gap_count = SELF_ID_GAP_COUNT(*sid);
202 	beta_repeaters_present = false;
203 
204 	while (sid < end) {
205 		next_sid = count_ports(sid, &port_count, &child_port_count);
206 
207 		if (next_sid == NULL) {
208 			fw_error("Inconsistent extended self IDs.\n");
209 			return NULL;
210 		}
211 
212 		q = *sid;
213 		if (phy_id != SELF_ID_PHY_ID(q)) {
214 			fw_error("PHY ID mismatch in self ID: %d != %d.\n",
215 				 phy_id, SELF_ID_PHY_ID(q));
216 			return NULL;
217 		}
218 
219 		if (child_port_count > stack_depth) {
220 			fw_error("Topology stack underflow\n");
221 			return NULL;
222 		}
223 
224 		/*
225 		 * Seek back from the top of our stack to find the
226 		 * start of the child nodes for this node.
227 		 */
228 		for (i = 0, h = &stack; i < child_port_count; i++)
229 			h = h->prev;
230 		/*
231 		 * When the stack is empty, this yields an invalid value,
232 		 * but that pointer will never be dereferenced.
233 		 */
234 		child = fw_node(h);
235 
236 		node = fw_node_create(q, port_count, card->color);
237 		if (node == NULL) {
238 			fw_error("Out of memory while building topology.\n");
239 			return NULL;
240 		}
241 
242 		if (phy_id == (card->node_id & 0x3f))
243 			local_node = node;
244 
245 		if (SELF_ID_CONTENDER(q))
246 			irm_node = node;
247 
248 		parent_count = 0;
249 
250 		for (i = 0; i < port_count; i++) {
251 			switch (get_port_type(sid, i)) {
252 			case SELFID_PORT_PARENT:
253 				/*
254 				 * Who's your daddy?  We dont know the
255 				 * parent node at this time, so we
256 				 * temporarily abuse node->color for
257 				 * remembering the entry in the
258 				 * node->ports array where the parent
259 				 * node should be.  Later, when we
260 				 * handle the parent node, we fix up
261 				 * the reference.
262 				 */
263 				parent_count++;
264 				node->color = i;
265 				break;
266 
267 			case SELFID_PORT_CHILD:
268 				node->ports[i] = child;
269 				/*
270 				 * Fix up parent reference for this
271 				 * child node.
272 				 */
273 				child->ports[child->color] = node;
274 				child->color = card->color;
275 				child = fw_node(child->link.next);
276 				break;
277 			}
278 		}
279 
280 		/*
281 		 * Check that the node reports exactly one parent
282 		 * port, except for the root, which of course should
283 		 * have no parents.
284 		 */
285 		if ((next_sid == end && parent_count != 0) ||
286 		    (next_sid < end && parent_count != 1)) {
287 			fw_error("Parent port inconsistency for node %d: "
288 				 "parent_count=%d\n", phy_id, parent_count);
289 			return NULL;
290 		}
291 
292 		/* Pop the child nodes off the stack and push the new node. */
293 		__list_del(h->prev, &stack);
294 		list_add_tail(&node->link, &stack);
295 		stack_depth += 1 - child_port_count;
296 
297 		if (node->phy_speed == SCODE_BETA &&
298 		    parent_count + child_port_count > 1)
299 			beta_repeaters_present = true;
300 
301 		/*
302 		 * If PHYs report different gap counts, set an invalid count
303 		 * which will force a gap count reconfiguration and a reset.
304 		 */
305 		if (SELF_ID_GAP_COUNT(q) != gap_count)
306 			gap_count = 0;
307 
308 		update_hop_count(node);
309 
310 		sid = next_sid;
311 		phy_id++;
312 	}
313 
314 	card->root_node = node;
315 	card->irm_node = irm_node;
316 	card->gap_count = gap_count;
317 	card->beta_repeaters_present = beta_repeaters_present;
318 
319 	return local_node;
320 }
321 
322 typedef void (*fw_node_callback_t)(struct fw_card * card,
323 				   struct fw_node * node,
324 				   struct fw_node * parent);
325 
326 static void for_each_fw_node(struct fw_card *card, struct fw_node *root,
327 			     fw_node_callback_t callback)
328 {
329 	struct list_head list;
330 	struct fw_node *node, *next, *child, *parent;
331 	int i;
332 
333 	INIT_LIST_HEAD(&list);
334 
335 	fw_node_get(root);
336 	list_add_tail(&root->link, &list);
337 	parent = NULL;
338 	list_for_each_entry(node, &list, link) {
339 		node->color = card->color;
340 
341 		for (i = 0; i < node->port_count; i++) {
342 			child = node->ports[i];
343 			if (!child)
344 				continue;
345 			if (child->color == card->color)
346 				parent = child;
347 			else {
348 				fw_node_get(child);
349 				list_add_tail(&child->link, &list);
350 			}
351 		}
352 
353 		callback(card, node, parent);
354 	}
355 
356 	list_for_each_entry_safe(node, next, &list, link)
357 		fw_node_put(node);
358 }
359 
360 static void report_lost_node(struct fw_card *card,
361 			     struct fw_node *node, struct fw_node *parent)
362 {
363 	fw_node_event(card, node, FW_NODE_DESTROYED);
364 	fw_node_put(node);
365 
366 	/* Topology has changed - reset bus manager retry counter */
367 	card->bm_retries = 0;
368 }
369 
370 static void report_found_node(struct fw_card *card,
371 			      struct fw_node *node, struct fw_node *parent)
372 {
373 	int b_path = (node->phy_speed == SCODE_BETA);
374 
375 	if (parent != NULL) {
376 		/* min() macro doesn't work here with gcc 3.4 */
377 		node->max_speed = parent->max_speed < node->phy_speed ?
378 					parent->max_speed : node->phy_speed;
379 		node->b_path = parent->b_path && b_path;
380 	} else {
381 		node->max_speed = node->phy_speed;
382 		node->b_path = b_path;
383 	}
384 
385 	fw_node_event(card, node, FW_NODE_CREATED);
386 
387 	/* Topology has changed - reset bus manager retry counter */
388 	card->bm_retries = 0;
389 }
390 
391 void fw_destroy_nodes(struct fw_card *card)
392 {
393 	unsigned long flags;
394 
395 	spin_lock_irqsave(&card->lock, flags);
396 	card->color++;
397 	if (card->local_node != NULL)
398 		for_each_fw_node(card, card->local_node, report_lost_node);
399 	card->local_node = NULL;
400 	spin_unlock_irqrestore(&card->lock, flags);
401 }
402 
403 static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
404 {
405 	struct fw_node *tree;
406 	int i;
407 
408 	tree = node1->ports[port];
409 	node0->ports[port] = tree;
410 	for (i = 0; i < tree->port_count; i++) {
411 		if (tree->ports[i] == node1) {
412 			tree->ports[i] = node0;
413 			break;
414 		}
415 	}
416 }
417 
418 /*
419  * Compare the old topology tree for card with the new one specified by root.
420  * Queue the nodes and mark them as either found, lost or updated.
421  * Update the nodes in the card topology tree as we go.
422  */
423 static void update_tree(struct fw_card *card, struct fw_node *root)
424 {
425 	struct list_head list0, list1;
426 	struct fw_node *node0, *node1, *next1;
427 	int i, event;
428 
429 	INIT_LIST_HEAD(&list0);
430 	list_add_tail(&card->local_node->link, &list0);
431 	INIT_LIST_HEAD(&list1);
432 	list_add_tail(&root->link, &list1);
433 
434 	node0 = fw_node(list0.next);
435 	node1 = fw_node(list1.next);
436 
437 	while (&node0->link != &list0) {
438 		WARN_ON(node0->port_count != node1->port_count);
439 
440 		if (node0->link_on && !node1->link_on)
441 			event = FW_NODE_LINK_OFF;
442 		else if (!node0->link_on && node1->link_on)
443 			event = FW_NODE_LINK_ON;
444 		else if (node1->initiated_reset && node1->link_on)
445 			event = FW_NODE_INITIATED_RESET;
446 		else
447 			event = FW_NODE_UPDATED;
448 
449 		node0->node_id = node1->node_id;
450 		node0->color = card->color;
451 		node0->link_on = node1->link_on;
452 		node0->initiated_reset = node1->initiated_reset;
453 		node0->max_hops = node1->max_hops;
454 		node1->color = card->color;
455 		fw_node_event(card, node0, event);
456 
457 		if (card->root_node == node1)
458 			card->root_node = node0;
459 		if (card->irm_node == node1)
460 			card->irm_node = node0;
461 
462 		for (i = 0; i < node0->port_count; i++) {
463 			if (node0->ports[i] && node1->ports[i]) {
464 				/*
465 				 * This port didn't change, queue the
466 				 * connected node for further
467 				 * investigation.
468 				 */
469 				if (node0->ports[i]->color == card->color)
470 					continue;
471 				list_add_tail(&node0->ports[i]->link, &list0);
472 				list_add_tail(&node1->ports[i]->link, &list1);
473 			} else if (node0->ports[i]) {
474 				/*
475 				 * The nodes connected here were
476 				 * unplugged; unref the lost nodes and
477 				 * queue FW_NODE_LOST callbacks for
478 				 * them.
479 				 */
480 
481 				for_each_fw_node(card, node0->ports[i],
482 						 report_lost_node);
483 				node0->ports[i] = NULL;
484 			} else if (node1->ports[i]) {
485 				/*
486 				 * One or more node were connected to
487 				 * this port. Move the new nodes into
488 				 * the tree and queue FW_NODE_CREATED
489 				 * callbacks for them.
490 				 */
491 				move_tree(node0, node1, i);
492 				for_each_fw_node(card, node0->ports[i],
493 						 report_found_node);
494 			}
495 		}
496 
497 		node0 = fw_node(node0->link.next);
498 		next1 = fw_node(node1->link.next);
499 		fw_node_put(node1);
500 		node1 = next1;
501 	}
502 }
503 
504 static void update_topology_map(struct fw_card *card,
505 				u32 *self_ids, int self_id_count)
506 {
507 	int node_count = (card->root_node->node_id & 0x3f) + 1;
508 	__be32 *map = card->topology_map;
509 
510 	*map++ = cpu_to_be32((self_id_count + 2) << 16);
511 	*map++ = cpu_to_be32(be32_to_cpu(card->topology_map[1]) + 1);
512 	*map++ = cpu_to_be32((node_count << 16) | self_id_count);
513 
514 	while (self_id_count--)
515 		*map++ = cpu_to_be32p(self_ids++);
516 
517 	fw_compute_block_crc(card->topology_map);
518 }
519 
520 void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,
521 			      int self_id_count, u32 *self_ids, bool bm_abdicate)
522 {
523 	struct fw_node *local_node;
524 	unsigned long flags;
525 
526 	/*
527 	 * If the selfID buffer is not the immediate successor of the
528 	 * previously processed one, we cannot reliably compare the
529 	 * old and new topologies.
530 	 */
531 	if (!is_next_generation(generation, card->generation) &&
532 	    card->local_node != NULL) {
533 		fw_notify("skipped bus generations, destroying all nodes\n");
534 		fw_destroy_nodes(card);
535 		card->bm_retries = 0;
536 	}
537 
538 	spin_lock_irqsave(&card->lock, flags);
539 
540 	card->broadcast_channel_allocated = card->broadcast_channel_auto_allocated;
541 	card->node_id = node_id;
542 	/*
543 	 * Update node_id before generation to prevent anybody from using
544 	 * a stale node_id together with a current generation.
545 	 */
546 	smp_wmb();
547 	card->generation = generation;
548 	card->reset_jiffies = get_jiffies_64();
549 	card->bm_node_id  = 0xffff;
550 	card->bm_abdicate = bm_abdicate;
551 	fw_schedule_bm_work(card, 0);
552 
553 	local_node = build_tree(card, self_ids, self_id_count);
554 
555 	update_topology_map(card, self_ids, self_id_count);
556 
557 	card->color++;
558 
559 	if (local_node == NULL) {
560 		fw_error("topology build failed\n");
561 		/* FIXME: We need to issue a bus reset in this case. */
562 	} else if (card->local_node == NULL) {
563 		card->local_node = local_node;
564 		for_each_fw_node(card, local_node, report_found_node);
565 	} else {
566 		update_tree(card, local_node);
567 	}
568 
569 	spin_unlock_irqrestore(&card->lock, flags);
570 }
571 EXPORT_SYMBOL(fw_core_handle_bus_reset);
572