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