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
count_ports(u32 * sid,int * total_port_count,int * child_port_count)53 static 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
get_port_type(u32 * sid,int port_index)102 static 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
fw_node_create(u32 sid,int port_count,int color)111 static 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 */
update_hop_count(struct fw_node * node)147 static 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
fw_node(struct list_head * l)171 static 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 */
build_tree(struct fw_card * card,u32 * sid,int self_id_count)183 static 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
321 typedef void (*fw_node_callback_t)(struct fw_card * card,
322 struct fw_node * node,
323 struct fw_node * parent);
324
for_each_fw_node(struct fw_card * card,struct fw_node * root,fw_node_callback_t callback)325 static 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
report_lost_node(struct fw_card * card,struct fw_node * node,struct fw_node * parent)359 static 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
report_found_node(struct fw_card * card,struct fw_node * node,struct fw_node * parent)369 static 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
fw_destroy_nodes(struct fw_card * card)390 void 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
move_tree(struct fw_node * node0,struct fw_node * node1,int port)402 static 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 */
update_tree(struct fw_card * card,struct fw_node * root)422 static 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
update_topology_map(struct fw_card * card,u32 * self_ids,int self_id_count)503 static 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
fw_core_handle_bus_reset(struct fw_card * card,int node_id,int generation,int self_id_count,u32 * self_ids,bool bm_abdicate)519 void 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 }
569 EXPORT_SYMBOL(fw_core_handle_bus_reset);
570