1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Incremental bus scan, based on bus topology
4 *
5 * Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net>
6 */
7
8 #include <linux/bug.h>
9 #include <linux/errno.h>
10 #include <linux/firewire.h>
11 #include <linux/firewire-constants.h>
12 #include <linux/jiffies.h>
13 #include <linux/kernel.h>
14 #include <linux/list.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/spinlock.h>
18
19 #include <linux/atomic.h>
20 #include <asm/byteorder.h>
21
22 #include "core.h"
23 #include "phy-packet-definitions.h"
24 #include <trace/events/firewire.h>
25
fw_node_create(u32 sid,int port_count,int color)26 static struct fw_node *fw_node_create(u32 sid, int port_count, int color)
27 {
28 struct fw_node *node;
29
30 node = kzalloc(struct_size(node, ports, port_count), GFP_ATOMIC);
31 if (node == NULL)
32 return NULL;
33
34 node->color = color;
35 node->node_id = LOCAL_BUS | phy_packet_self_id_get_phy_id(sid);
36 node->link_on = phy_packet_self_id_zero_get_link_active(sid);
37 // NOTE: Only two bits, thus only for SCODE_100, SCODE_200, SCODE_400, and SCODE_BETA.
38 node->phy_speed = phy_packet_self_id_zero_get_scode(sid);
39 node->initiated_reset = phy_packet_self_id_zero_get_initiated_reset(sid);
40 node->port_count = port_count;
41
42 kref_init(&node->kref);
43 INIT_LIST_HEAD(&node->link);
44
45 return node;
46 }
47
48 /*
49 * Compute the maximum hop count for this node and it's children. The
50 * maximum hop count is the maximum number of connections between any
51 * two nodes in the subtree rooted at this node. We need this for
52 * setting the gap count. As we build the tree bottom up in
53 * build_tree() below, this is fairly easy to do: for each node we
54 * maintain the max hop count and the max depth, ie the number of hops
55 * to the furthest leaf. Computing the max hop count breaks down into
56 * two cases: either the path goes through this node, in which case
57 * the hop count is the sum of the two biggest child depths plus 2.
58 * Or it could be the case that the max hop path is entirely
59 * contained in a child tree, in which case the max hop count is just
60 * the max hop count of this child.
61 */
update_hop_count(struct fw_node * node)62 static void update_hop_count(struct fw_node *node)
63 {
64 int depths[2] = { -1, -1 };
65 int max_child_hops = 0;
66 int i;
67
68 for (i = 0; i < node->port_count; i++) {
69 if (node->ports[i] == NULL)
70 continue;
71
72 if (node->ports[i]->max_hops > max_child_hops)
73 max_child_hops = node->ports[i]->max_hops;
74
75 if (node->ports[i]->max_depth > depths[0]) {
76 depths[1] = depths[0];
77 depths[0] = node->ports[i]->max_depth;
78 } else if (node->ports[i]->max_depth > depths[1])
79 depths[1] = node->ports[i]->max_depth;
80 }
81
82 node->max_depth = depths[0] + 1;
83 node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2);
84 }
85
fw_node(struct list_head * l)86 static inline struct fw_node *fw_node(struct list_head *l)
87 {
88 return list_entry(l, struct fw_node, link);
89 }
90
91 /*
92 * This function builds the tree representation of the topology given
93 * by the self IDs from the latest bus reset. During the construction
94 * of the tree, the function checks that the self IDs are valid and
95 * internally consistent. On success this function returns the
96 * fw_node corresponding to the local card otherwise NULL.
97 */
build_tree(struct fw_card * card,const u32 * sid,int self_id_count,unsigned int generation)98 static struct fw_node *build_tree(struct fw_card *card, const u32 *sid, int self_id_count,
99 unsigned int generation)
100 {
101 struct self_id_sequence_enumerator enumerator = {
102 .cursor = sid,
103 .quadlet_count = self_id_count,
104 };
105 struct fw_node *node, *child, *local_node, *irm_node;
106 struct list_head stack;
107 int phy_id, stack_depth;
108 int gap_count;
109 bool beta_repeaters_present;
110
111 local_node = NULL;
112 node = NULL;
113 INIT_LIST_HEAD(&stack);
114 stack_depth = 0;
115 phy_id = 0;
116 irm_node = NULL;
117 gap_count = phy_packet_self_id_zero_get_gap_count(*sid);
118 beta_repeaters_present = false;
119
120 while (enumerator.quadlet_count > 0) {
121 unsigned int child_port_count = 0;
122 unsigned int total_port_count = 0;
123 unsigned int parent_count = 0;
124 unsigned int quadlet_count;
125 const u32 *self_id_sequence;
126 unsigned int port_capacity;
127 enum phy_packet_self_id_port_status port_status;
128 unsigned int port_index;
129 struct list_head *h;
130 int i;
131
132 self_id_sequence = self_id_sequence_enumerator_next(&enumerator, &quadlet_count);
133 if (IS_ERR(self_id_sequence)) {
134 if (PTR_ERR(self_id_sequence) != -ENODATA) {
135 fw_err(card, "inconsistent extended self IDs: %ld\n",
136 PTR_ERR(self_id_sequence));
137 return NULL;
138 }
139 break;
140 }
141
142 port_capacity = self_id_sequence_get_port_capacity(quadlet_count);
143 trace_self_id_sequence(card->index, self_id_sequence, quadlet_count, generation);
144
145 for (port_index = 0; port_index < port_capacity; ++port_index) {
146 port_status = self_id_sequence_get_port_status(self_id_sequence, quadlet_count,
147 port_index);
148 switch (port_status) {
149 case PHY_PACKET_SELF_ID_PORT_STATUS_CHILD:
150 ++child_port_count;
151 fallthrough;
152 case PHY_PACKET_SELF_ID_PORT_STATUS_PARENT:
153 case PHY_PACKET_SELF_ID_PORT_STATUS_NCONN:
154 ++total_port_count;
155 fallthrough;
156 case PHY_PACKET_SELF_ID_PORT_STATUS_NONE:
157 default:
158 break;
159 }
160 }
161
162 if (phy_id != phy_packet_self_id_get_phy_id(self_id_sequence[0])) {
163 fw_err(card, "PHY ID mismatch in self ID: %d != %d\n",
164 phy_id, phy_packet_self_id_get_phy_id(self_id_sequence[0]));
165 return NULL;
166 }
167
168 if (child_port_count > stack_depth) {
169 fw_err(card, "topology stack underflow\n");
170 return NULL;
171 }
172
173 /*
174 * Seek back from the top of our stack to find the
175 * start of the child nodes for this node.
176 */
177 for (i = 0, h = &stack; i < child_port_count; i++)
178 h = h->prev;
179 /*
180 * When the stack is empty, this yields an invalid value,
181 * but that pointer will never be dereferenced.
182 */
183 child = fw_node(h);
184
185 node = fw_node_create(self_id_sequence[0], total_port_count, card->color);
186 if (node == NULL) {
187 fw_err(card, "out of memory while building topology\n");
188 return NULL;
189 }
190
191 if (phy_id == (card->node_id & 0x3f))
192 local_node = node;
193
194 if (phy_packet_self_id_zero_get_contender(self_id_sequence[0]))
195 irm_node = node;
196
197 for (port_index = 0; port_index < total_port_count; ++port_index) {
198 port_status = self_id_sequence_get_port_status(self_id_sequence, quadlet_count,
199 port_index);
200 switch (port_status) {
201 case PHY_PACKET_SELF_ID_PORT_STATUS_PARENT:
202 // Who's your daddy? We dont know the parent node at this time, so
203 // we temporarily abuse node->color for remembering the entry in
204 // the node->ports array where the parent node should be. Later,
205 // when we handle the parent node, we fix up the reference.
206 ++parent_count;
207 node->color = port_index;
208 break;
209
210 case PHY_PACKET_SELF_ID_PORT_STATUS_CHILD:
211 node->ports[port_index] = child;
212 // Fix up parent reference for this child node.
213 child->ports[child->color] = node;
214 child->color = card->color;
215 child = fw_node(child->link.next);
216 break;
217 case PHY_PACKET_SELF_ID_PORT_STATUS_NCONN:
218 case PHY_PACKET_SELF_ID_PORT_STATUS_NONE:
219 default:
220 break;
221 }
222 }
223
224 // Check that the node reports exactly one parent port, except for the root, which
225 // of course should have no parents.
226 if ((enumerator.quadlet_count == 0 && parent_count != 0) ||
227 (enumerator.quadlet_count > 0 && parent_count != 1)) {
228 fw_err(card, "parent port inconsistency for node %d: "
229 "parent_count=%d\n", phy_id, parent_count);
230 return NULL;
231 }
232
233 /* Pop the child nodes off the stack and push the new node. */
234 __list_del(h->prev, &stack);
235 list_add_tail(&node->link, &stack);
236 stack_depth += 1 - child_port_count;
237
238 if (node->phy_speed == SCODE_BETA && parent_count + child_port_count > 1)
239 beta_repeaters_present = true;
240
241 // If PHYs report different gap counts, set an invalid count which will force a gap
242 // count reconfiguration and a reset.
243 if (phy_packet_self_id_zero_get_gap_count(self_id_sequence[0]) != gap_count)
244 gap_count = 0;
245
246 update_hop_count(node);
247
248 phy_id++;
249 }
250
251 card->root_node = node;
252 card->irm_node = irm_node;
253 card->gap_count = gap_count;
254 card->beta_repeaters_present = beta_repeaters_present;
255
256 return local_node;
257 }
258
259 typedef void (*fw_node_callback_t)(struct fw_card * card,
260 struct fw_node * node,
261 struct fw_node * parent);
262
for_each_fw_node(struct fw_card * card,struct fw_node * root,fw_node_callback_t callback)263 static void for_each_fw_node(struct fw_card *card, struct fw_node *root,
264 fw_node_callback_t callback)
265 {
266 struct list_head list;
267 struct fw_node *node, *next, *child, *parent;
268 int i;
269
270 INIT_LIST_HEAD(&list);
271
272 fw_node_get(root);
273 list_add_tail(&root->link, &list);
274 parent = NULL;
275 list_for_each_entry(node, &list, link) {
276 node->color = card->color;
277
278 for (i = 0; i < node->port_count; i++) {
279 child = node->ports[i];
280 if (!child)
281 continue;
282 if (child->color == card->color)
283 parent = child;
284 else {
285 fw_node_get(child);
286 list_add_tail(&child->link, &list);
287 }
288 }
289
290 callback(card, node, parent);
291 }
292
293 list_for_each_entry_safe(node, next, &list, link)
294 fw_node_put(node);
295 }
296
report_lost_node(struct fw_card * card,struct fw_node * node,struct fw_node * parent)297 static void report_lost_node(struct fw_card *card,
298 struct fw_node *node, struct fw_node *parent)
299 {
300 fw_node_event(card, node, FW_NODE_DESTROYED);
301 fw_node_put(node);
302
303 /* Topology has changed - reset bus manager retry counter */
304 card->bm_retries = 0;
305 }
306
report_found_node(struct fw_card * card,struct fw_node * node,struct fw_node * parent)307 static void report_found_node(struct fw_card *card,
308 struct fw_node *node, struct fw_node *parent)
309 {
310 int b_path = (node->phy_speed == SCODE_BETA);
311
312 if (parent != NULL) {
313 /* min() macro doesn't work here with gcc 3.4 */
314 node->max_speed = parent->max_speed < node->phy_speed ?
315 parent->max_speed : node->phy_speed;
316 node->b_path = parent->b_path && b_path;
317 } else {
318 node->max_speed = node->phy_speed;
319 node->b_path = b_path;
320 }
321
322 fw_node_event(card, node, FW_NODE_CREATED);
323
324 /* Topology has changed - reset bus manager retry counter */
325 card->bm_retries = 0;
326 }
327
328 /* Must be called with card->lock held */
fw_destroy_nodes(struct fw_card * card)329 void fw_destroy_nodes(struct fw_card *card)
330 {
331 card->color++;
332 if (card->local_node != NULL)
333 for_each_fw_node(card, card->local_node, report_lost_node);
334 card->local_node = NULL;
335 }
336
move_tree(struct fw_node * node0,struct fw_node * node1,int port)337 static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
338 {
339 struct fw_node *tree;
340 int i;
341
342 tree = node1->ports[port];
343 node0->ports[port] = tree;
344 for (i = 0; i < tree->port_count; i++) {
345 if (tree->ports[i] == node1) {
346 tree->ports[i] = node0;
347 break;
348 }
349 }
350 }
351
352 /*
353 * Compare the old topology tree for card with the new one specified by root.
354 * Queue the nodes and mark them as either found, lost or updated.
355 * Update the nodes in the card topology tree as we go.
356 */
update_tree(struct fw_card * card,struct fw_node * root)357 static void update_tree(struct fw_card *card, struct fw_node *root)
358 {
359 struct list_head list0, list1;
360 struct fw_node *node0, *node1, *next1;
361 int i, event;
362
363 INIT_LIST_HEAD(&list0);
364 list_add_tail(&card->local_node->link, &list0);
365 INIT_LIST_HEAD(&list1);
366 list_add_tail(&root->link, &list1);
367
368 node0 = fw_node(list0.next);
369 node1 = fw_node(list1.next);
370
371 while (&node0->link != &list0) {
372 WARN_ON(node0->port_count != node1->port_count);
373
374 if (node0->link_on && !node1->link_on)
375 event = FW_NODE_LINK_OFF;
376 else if (!node0->link_on && node1->link_on)
377 event = FW_NODE_LINK_ON;
378 else if (node1->initiated_reset && node1->link_on)
379 event = FW_NODE_INITIATED_RESET;
380 else
381 event = FW_NODE_UPDATED;
382
383 node0->node_id = node1->node_id;
384 node0->color = card->color;
385 node0->link_on = node1->link_on;
386 node0->initiated_reset = node1->initiated_reset;
387 node0->max_hops = node1->max_hops;
388 node1->color = card->color;
389 fw_node_event(card, node0, event);
390
391 if (card->root_node == node1)
392 card->root_node = node0;
393 if (card->irm_node == node1)
394 card->irm_node = node0;
395
396 for (i = 0; i < node0->port_count; i++) {
397 if (node0->ports[i] && node1->ports[i]) {
398 /*
399 * This port didn't change, queue the
400 * connected node for further
401 * investigation.
402 */
403 if (node0->ports[i]->color == card->color)
404 continue;
405 list_add_tail(&node0->ports[i]->link, &list0);
406 list_add_tail(&node1->ports[i]->link, &list1);
407 } else if (node0->ports[i]) {
408 /*
409 * The nodes connected here were
410 * unplugged; unref the lost nodes and
411 * queue FW_NODE_LOST callbacks for
412 * them.
413 */
414
415 for_each_fw_node(card, node0->ports[i],
416 report_lost_node);
417 node0->ports[i] = NULL;
418 } else if (node1->ports[i]) {
419 /*
420 * One or more node were connected to
421 * this port. Move the new nodes into
422 * the tree and queue FW_NODE_CREATED
423 * callbacks for them.
424 */
425 move_tree(node0, node1, i);
426 for_each_fw_node(card, node0->ports[i],
427 report_found_node);
428 }
429 }
430
431 node0 = fw_node(node0->link.next);
432 next1 = fw_node(node1->link.next);
433 fw_node_put(node1);
434 node1 = next1;
435 }
436 }
437
update_topology_map(struct fw_card * card,u32 * self_ids,int self_id_count)438 static void update_topology_map(struct fw_card *card,
439 u32 *self_ids, int self_id_count)
440 {
441 int node_count = (card->root_node->node_id & 0x3f) + 1;
442 __be32 *map = card->topology_map;
443
444 *map++ = cpu_to_be32((self_id_count + 2) << 16);
445 *map++ = cpu_to_be32(be32_to_cpu(card->topology_map[1]) + 1);
446 *map++ = cpu_to_be32((node_count << 16) | self_id_count);
447
448 while (self_id_count--)
449 *map++ = cpu_to_be32p(self_ids++);
450
451 fw_compute_block_crc(card->topology_map);
452 }
453
fw_core_handle_bus_reset(struct fw_card * card,int node_id,int generation,int self_id_count,u32 * self_ids,bool bm_abdicate)454 void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,
455 int self_id_count, u32 *self_ids, bool bm_abdicate)
456 {
457 struct fw_node *local_node;
458
459 trace_bus_reset_handle(card->index, generation, node_id, bm_abdicate, self_ids, self_id_count);
460
461 guard(spinlock_irqsave)(&card->lock);
462
463 /*
464 * If the selfID buffer is not the immediate successor of the
465 * previously processed one, we cannot reliably compare the
466 * old and new topologies.
467 */
468 if (!is_next_generation(generation, card->generation) &&
469 card->local_node != NULL) {
470 fw_destroy_nodes(card);
471 card->bm_retries = 0;
472 }
473
474 card->broadcast_channel_allocated = card->broadcast_channel_auto_allocated;
475 card->node_id = node_id;
476 /*
477 * Update node_id before generation to prevent anybody from using
478 * a stale node_id together with a current generation.
479 */
480 smp_wmb();
481 card->generation = generation;
482 card->reset_jiffies = get_jiffies_64();
483 card->bm_node_id = 0xffff;
484 card->bm_abdicate = bm_abdicate;
485 fw_schedule_bm_work(card, 0);
486
487 local_node = build_tree(card, self_ids, self_id_count, generation);
488
489 update_topology_map(card, self_ids, self_id_count);
490
491 card->color++;
492
493 if (local_node == NULL) {
494 fw_err(card, "topology build failed\n");
495 /* FIXME: We need to issue a bus reset in this case. */
496 } else if (card->local_node == NULL) {
497 card->local_node = local_node;
498 for_each_fw_node(card, local_node, report_found_node);
499 } else {
500 update_tree(card, local_node);
501 }
502 }
503 EXPORT_SYMBOL(fw_core_handle_bus_reset);
504