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