/drivers/firewire/core-topology.c

  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
 54static 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
103static 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
112static 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 */
148static 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
172static inline struct fw_node *fw_node(struct list_head *l)
173{
174	return list_entry(l, struct fw_node, link);
175}
176
177/**
178 * build_tree - Build the tree representation of the topology
179 * @self_ids: array of self IDs to create the tree from
180 * @self_id_count: the length of the self_ids array
181 * @local_id: the node ID of the local node
182 *
183 * This function builds the tree representation of the topology given
184 * by the self IDs from the latest bus reset.  During the construction
185 * of the tree, the function checks that the self IDs are valid and
186 * internally consistent.  On success this function returns the
187 * fw_node corresponding to the local card otherwise NULL.
188 */
189static struct fw_node *build_tree(struct fw_card *card,
190				  u32 *sid, int self_id_count)
191{
192	struct fw_node *node, *child, *local_node, *irm_node;
193	struct list_head stack, *h;
194	u32 *next_sid, *end, q;
195	int i, port_count, child_port_count, phy_id, parent_count, stack_depth;
196	int gap_count;
197	bool beta_repeaters_present;
198
199	local_node = NULL;
200	node = NULL;
201	INIT_LIST_HEAD(&stack);
202	stack_depth = 0;
203	end = sid + self_id_count;
204	phy_id = 0;
205	irm_node = NULL;
206	gap_count = SELF_ID_GAP_COUNT(*sid);
207	beta_repeaters_present = false;
208
209	while (sid < end) {
210		next_sid = count_ports(sid, &port_count, &child_port_count);
211
212		if (next_sid == NULL) {
213			fw_error("Inconsistent extended self IDs.\n");
214			return NULL;
215		}
216
217		q = *sid;
218		if (phy_id != SELF_ID_PHY_ID(q)) {
219			fw_error("PHY ID mismatch in self ID: %d != %d.\n",
220				 phy_id, SELF_ID_PHY_ID(q));
221			return NULL;
222		}
223
224		if (child_port_count > stack_depth) {
225			fw_error("Topology stack underflow\n");
226			return NULL;
227		}
228
229		/*
230		 * Seek back from the top of our stack to find the
231		 * start of the child nodes for this node.
232		 */
233		for (i = 0, h = &stack; i < child_port_count; i++)
234			h = h->prev;
235		/*
236		 * When the stack is empty, this yields an invalid value,
237		 * but that pointer will never be dereferenced.
238		 */
239		child = fw_node(h);
240
241		node = fw_node_create(q, port_count, card->color);
242		if (node == NULL) {
243			fw_error("Out of memory while building topology.\n");
244			return NULL;
245		}
246
247		if (phy_id == (card->node_id & 0x3f))
248			local_node = node;
249
250		if (SELF_ID_CONTENDER(q))
251			irm_node = node;
252
253		parent_count = 0;
254
255		for (i = 0; i < port_count; i++) {
256			switch (get_port_type(sid, i)) {
257			case SELFID_PORT_PARENT:
258				/*
259				 * Who's your daddy?  We dont know the
260				 * parent node at this time, so we
261				 * temporarily abuse node->color for
262				 * remembering the entry in the
263				 * node->ports array where the parent
264				 * node should be.  Later, when we
265				 * handle the parent node, we fix up
266				 * the reference.
267				 */
268				parent_count++;
269				node->color = i;
270				break;
271
272			case SELFID_PORT_CHILD:
273				node->ports[i] = child;
274				/*
275				 * Fix up parent reference for this
276				 * child node.
277				 */
278				child->ports[child->color] = node;
279				child->color = card->color;
280				child = fw_node(child->link.next);
281				break;
282			}
283		}
284
285		/*
286		 * Check that the node reports exactly one parent
287		 * port, except for the root, which of course should
288		 * have no parents.
289		 */
290		if ((next_sid == end && parent_count != 0) ||
291		    (next_sid < end && parent_count != 1)) {
292			fw_error("Parent port inconsistency for node %d: "
293				 "parent_count=%d\n", phy_id, parent_count);
294			return NULL;
295		}
296
297		/* Pop the child nodes off the stack and push the new node. */
298		__list_del(h->prev, &stack);
299		list_add_tail(&node->link, &stack);
300		stack_depth += 1 - child_port_count;
301
302		if (node->phy_speed == SCODE_BETA &&
303		    parent_count + child_port_count > 1)
304			beta_repeaters_present = true;
305
306		/*
307		 * If PHYs report different gap counts, set an invalid count
308		 * which will force a gap count reconfiguration and a reset.
309		 */
310		if (SELF_ID_GAP_COUNT(q) != gap_count)
311			gap_count = 0;
312
313		update_hop_count(node);
314
315		sid = next_sid;
316		phy_id++;
317	}
318
319	card->root_node = node;
320	card->irm_node = irm_node;
321	card->gap_count = gap_count;
322	card->beta_repeaters_present = beta_repeaters_present;
323
324	return local_node;
325}
326
327typedef void (*fw_node_callback_t)(struct fw_card * card,
328				   struct fw_node * node,
329				   struct fw_node * parent);
330
331static void for_each_fw_node(struct fw_card *card, struct fw_node *root,
332			     fw_node_callback_t callback)
333{
334	struct list_head list;
335	struct fw_node *node, *next, *child, *parent;
336	int i;
337
338	INIT_LIST_HEAD(&list);
339
340	fw_node_get(root);
341	list_add_tail(&root->link, &list);
342	parent = NULL;
343	list_for_each_entry(node, &list, link) {
344		node->color = card->color;
345
346		for (i = 0; i < node->port_count; i++) {
347			child = node->ports[i];
348			if (!child)
349				continue;
350			if (child->color == card->color)
351				parent = child;
352			else {
353				fw_node_get(child);
354				list_add_tail(&child->link, &list);
355			}
356		}
357
358		callback(card, node, parent);
359	}
360
361	list_for_each_entry_safe(node, next, &list, link)
362		fw_node_put(node);
363}
364
365static void report_lost_node(struct fw_card *card,
366			     struct fw_node *node, struct fw_node *parent)
367{
368	fw_node_event(card, node, FW_NODE_DESTROYED);
369	fw_node_put(node);
370
371	/* Topology has changed - reset bus manager retry counter */
372	card->bm_retries = 0;
373}
374
375static void report_found_node(struct fw_card *card,
376			      struct fw_node *node, struct fw_node *parent)
377{
378	int b_path = (node->phy_speed == SCODE_BETA);
379
380	if (parent != NULL) {
381		/* min() macro doesn't work here with gcc 3.4 */
382		node->max_speed = parent->max_speed < node->phy_speed ?
383					parent->max_speed : node->phy_speed;
384		node->b_path = parent->b_path && b_path;
385	} else {
386		node->max_speed = node->phy_speed;
387		node->b_path = b_path;
388	}
389
390	fw_node_event(card, node, FW_NODE_CREATED);
391
392	/* Topology has changed - reset bus manager retry counter */
393	card->bm_retries = 0;
394}
395
396void fw_destroy_nodes(struct fw_card *card)
397{
398	unsigned long flags;
399
400	spin_lock_irqsave(&card->lock, flags);
401	card->color++;
402	if (card->local_node != NULL)
403		for_each_fw_node(card, card->local_node, report_lost_node);
404	card->local_node = NULL;
405	spin_unlock_irqrestore(&card->lock, flags);
406}
407
408static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
409{
410	struct fw_node *tree;
411	int i;
412
413	tree = node1->ports[port];
414	node0->ports[port] = tree;
415	for (i = 0; i < tree->port_count; i++) {
416		if (tree->ports[i] == node1) {
417			tree->ports[i] = node0;
418			break;
419		}
420	}
421}
422
423/**
424 * update_tree - compare the old topology tree for card with the new
425 * one specified by root.  Queue the nodes and mark them as either
426 * found, lost or updated.  Update the nodes in the card topology tree
427 * as we go.
428 */
429static void update_tree(struct fw_card *card, struct fw_node *root)
430{
431	struct list_head list0, list1;
432	struct fw_node *node0, *node1, *next1;
433	int i, event;
434
435	INIT_LIST_HEAD(&list0);
436	list_add_tail(&card->local_node->link, &list0);
437	INIT_LIST_HEAD(&list1);
438	list_add_tail(&root->link, &list1);
439
440	node0 = fw_node(list0.next);
441	node1 = fw_node(list1.next);
442
443	while (&node0->link != &list0) {
444		WARN_ON(node0->port_count != node1->port_count);
445
446		if (node0->link_on && !node1->link_on)
447			event = FW_NODE_LINK_OFF;
448		else if (!node0->link_on && node1->link_on)
449			event = FW_NODE_LINK_ON;
450		else if (node1->initiated_reset && node1->link_on)
451			event = FW_NODE_INITIATED_RESET;
452		else
453			event = FW_NODE_UPDATED;
454
455		node0->node_id = node1->node_id;
456		node0->color = card->color;
457		node0->link_on = node1->link_on;
458		node0->initiated_reset = node1->initiated_reset;
459		node0->max_hops = node1->max_hops;
460		node1->color = card->color;
461		fw_node_event(card, node0, event);
462
463		if (card->root_node == node1)
464			card->root_node = node0;
465		if (card->irm_node == node1)
466			card->irm_node = node0;
467
468		for (i = 0; i < node0->port_count; i++) {
469			if (node0->ports[i] && node1->ports[i]) {
470				/*
471				 * This port didn't change, queue the
472				 * connected node for further
473				 * investigation.
474				 */
475				if (node0->ports[i]->color == card->color)
476					continue;
477				list_add_tail(&node0->ports[i]->link, &list0);
478				list_add_tail(&node1->ports[i]->link, &list1);
479			} else if (node0->ports[i]) {
480				/*
481				 * The nodes connected here were
482				 * unplugged; unref the lost nodes and
483				 * queue FW_NODE_LOST callbacks for
484				 * them.
485				 */
486
487				for_each_fw_node(card, node0->ports[i],
488						 report_lost_node);
489				node0->ports[i] = NULL;
490			} else if (node1->ports[i]) {
491				/*
492				 * One or more node were connected to
493				 * this port. Move the new nodes into
494				 * the tree and queue FW_NODE_CREATED
495				 * callbacks for them.
496				 */
497				move_tree(node0, node1, i);
498				for_each_fw_node(card, node0->ports[i],
499						 report_found_node);
500			}
501		}
502
503		node0 = fw_node(node0->link.next);
504		next1 = fw_node(node1->link.next);
505		fw_node_put(node1);
506		node1 = next1;
507	}
508}
509
510static void update_topology_map(struct fw_card *card,
511				u32 *self_ids, int self_id_count)
512{
513	int node_count = (card->root_node->node_id & 0x3f) + 1;
514	__be32 *map = card->topology_map;
515
516	*map++ = cpu_to_be32((self_id_count + 2) << 16);
517	*map++ = cpu_to_be32(be32_to_cpu(card->topology_map[1]) + 1);
518	*map++ = cpu_to_be32((node_count << 16) | self_id_count);
519
520	while (self_id_count--)
521		*map++ = cpu_to_be32p(self_ids++);
522
523	fw_compute_block_crc(card->topology_map);
524}
525
526void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,
527			      int self_id_count, u32 *self_ids)
528{
529	struct fw_node *local_node;
530	unsigned long flags;
531
532	/*
533	 * If the selfID buffer is not the immediate successor of the
534	 * previously processed one, we cannot reliably compare the
535	 * old and new topologies.
536	 */
537	if (!is_next_generation(generation, card->generation) &&
538	    card->local_node != NULL) {
539		fw_notify("skipped bus generations, destroying all nodes\n");
540		fw_destroy_nodes(card);
541		card->bm_retries = 0;
542	}
543
544	spin_lock_irqsave(&card->lock, flags);
545
546	card->broadcast_channel_allocated = false;
547	card->node_id = node_id;
548	/*
549	 * Update node_id before generation to prevent anybody from using
550	 * a stale node_id together with a current generation.
551	 */
552	smp_wmb();
553	card->generation = generation;
554	card->reset_jiffies = jiffies;
555	fw_schedule_bm_work(card, 0);
556
557	local_node = build_tree(card, self_ids, self_id_count);
558
559	update_topology_map(card, self_ids, self_id_count);
560
561	card->color++;
562
563	if (local_node == NULL) {
564		fw_error("topology build failed\n");
565		/* FIXME: We need to issue a bus reset in this case. */
566	} else if (card->local_node == NULL) {
567		card->local_node = local_node;
568		for_each_fw_node(card, local_node, report_found_node);
569	} else {
570		update_tree(card, local_node);
571	}
572
573	spin_unlock_irqrestore(&card->lock, flags);
574}
575EXPORT_SYMBOL(fw_core_handle_bus_reset);