Merge drm/drm-next into drm-intel-gt-next
[linux-2.6-microblaze.git] / drivers / firewire / core-topology.c
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
24 #define SELF_ID_PHY_ID(q)               (((q) >> 24) & 0x3f)
25 #define SELF_ID_EXTENDED(q)             (((q) >> 23) & 0x01)
26 #define SELF_ID_LINK_ON(q)              (((q) >> 22) & 0x01)
27 #define SELF_ID_GAP_COUNT(q)            (((q) >> 16) & 0x3f)
28 #define SELF_ID_PHY_SPEED(q)            (((q) >> 14) & 0x03)
29 #define SELF_ID_CONTENDER(q)            (((q) >> 11) & 0x01)
30 #define SELF_ID_PHY_INITIATOR(q)        (((q) >>  1) & 0x01)
31 #define SELF_ID_MORE_PACKETS(q)         (((q) >>  0) & 0x01)
32
33 #define SELF_ID_EXT_SEQUENCE(q)         (((q) >> 20) & 0x07)
34
35 #define SELFID_PORT_CHILD       0x3
36 #define SELFID_PORT_PARENT      0x2
37 #define SELFID_PORT_NCONN       0x1
38 #define SELFID_PORT_NONE        0x0
39
40 static u32 *count_ports(u32 *sid, int *total_port_count, int *child_port_count)
41 {
42         u32 q;
43         int port_type, shift, seq;
44
45         *total_port_count = 0;
46         *child_port_count = 0;
47
48         shift = 6;
49         q = *sid;
50         seq = 0;
51
52         while (1) {
53                 port_type = (q >> shift) & 0x03;
54                 switch (port_type) {
55                 case SELFID_PORT_CHILD:
56                         (*child_port_count)++;
57                         fallthrough;
58                 case SELFID_PORT_PARENT:
59                 case SELFID_PORT_NCONN:
60                         (*total_port_count)++;
61                         fallthrough;
62                 case SELFID_PORT_NONE:
63                         break;
64                 }
65
66                 shift -= 2;
67                 if (shift == 0) {
68                         if (!SELF_ID_MORE_PACKETS(q))
69                                 return sid + 1;
70
71                         shift = 16;
72                         sid++;
73                         q = *sid;
74
75                         /*
76                          * Check that the extra packets actually are
77                          * extended self ID packets and that the
78                          * sequence numbers in the extended self ID
79                          * packets increase as expected.
80                          */
81
82                         if (!SELF_ID_EXTENDED(q) ||
83                             seq != SELF_ID_EXT_SEQUENCE(q))
84                                 return NULL;
85
86                         seq++;
87                 }
88         }
89 }
90
91 static int get_port_type(u32 *sid, int port_index)
92 {
93         int index, shift;
94
95         index = (port_index + 5) / 8;
96         shift = 16 - ((port_index + 5) & 7) * 2;
97         return (sid[index] >> shift) & 0x03;
98 }
99
100 static struct fw_node *fw_node_create(u32 sid, int port_count, int color)
101 {
102         struct fw_node *node;
103
104         node = kzalloc(struct_size(node, ports, port_count), GFP_ATOMIC);
105         if (node == NULL)
106                 return NULL;
107
108         node->color = color;
109         node->node_id = LOCAL_BUS | SELF_ID_PHY_ID(sid);
110         node->link_on = SELF_ID_LINK_ON(sid);
111         node->phy_speed = SELF_ID_PHY_SPEED(sid);
112         node->initiated_reset = SELF_ID_PHY_INITIATOR(sid);
113         node->port_count = port_count;
114
115         refcount_set(&node->ref_count, 1);
116         INIT_LIST_HEAD(&node->link);
117
118         return node;
119 }
120
121 /*
122  * Compute the maximum hop count for this node and it's children.  The
123  * maximum hop count is the maximum number of connections between any
124  * two nodes in the subtree rooted at this node.  We need this for
125  * setting the gap count.  As we build the tree bottom up in
126  * build_tree() below, this is fairly easy to do: for each node we
127  * maintain the max hop count and the max depth, ie the number of hops
128  * to the furthest leaf.  Computing the max hop count breaks down into
129  * two cases: either the path goes through this node, in which case
130  * the hop count is the sum of the two biggest child depths plus 2.
131  * Or it could be the case that the max hop path is entirely
132  * containted in a child tree, in which case the max hop count is just
133  * the max hop count of this child.
134  */
135 static void update_hop_count(struct fw_node *node)
136 {
137         int depths[2] = { -1, -1 };
138         int max_child_hops = 0;
139         int i;
140
141         for (i = 0; i < node->port_count; i++) {
142                 if (node->ports[i] == NULL)
143                         continue;
144
145                 if (node->ports[i]->max_hops > max_child_hops)
146                         max_child_hops = node->ports[i]->max_hops;
147
148                 if (node->ports[i]->max_depth > depths[0]) {
149                         depths[1] = depths[0];
150                         depths[0] = node->ports[i]->max_depth;
151                 } else if (node->ports[i]->max_depth > depths[1])
152                         depths[1] = node->ports[i]->max_depth;
153         }
154
155         node->max_depth = depths[0] + 1;
156         node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2);
157 }
158
159 static inline struct fw_node *fw_node(struct list_head *l)
160 {
161         return list_entry(l, struct fw_node, link);
162 }
163
164 /*
165  * This function builds the tree representation of the topology given
166  * by the self IDs from the latest bus reset.  During the construction
167  * of the tree, the function checks that the self IDs are valid and
168  * internally consistent.  On success this function returns the
169  * fw_node corresponding to the local card otherwise NULL.
170  */
171 static struct fw_node *build_tree(struct fw_card *card,
172                                   u32 *sid, int self_id_count)
173 {
174         struct fw_node *node, *child, *local_node, *irm_node;
175         struct list_head stack, *h;
176         u32 *next_sid, *end, q;
177         int i, port_count, child_port_count, phy_id, parent_count, stack_depth;
178         int gap_count;
179         bool beta_repeaters_present;
180
181         local_node = NULL;
182         node = NULL;
183         INIT_LIST_HEAD(&stack);
184         stack_depth = 0;
185         end = sid + self_id_count;
186         phy_id = 0;
187         irm_node = NULL;
188         gap_count = SELF_ID_GAP_COUNT(*sid);
189         beta_repeaters_present = false;
190
191         while (sid < end) {
192                 next_sid = count_ports(sid, &port_count, &child_port_count);
193
194                 if (next_sid == NULL) {
195                         fw_err(card, "inconsistent extended self IDs\n");
196                         return NULL;
197                 }
198
199                 q = *sid;
200                 if (phy_id != SELF_ID_PHY_ID(q)) {
201                         fw_err(card, "PHY ID mismatch in self ID: %d != %d\n",
202                                phy_id, SELF_ID_PHY_ID(q));
203                         return NULL;
204                 }
205
206                 if (child_port_count > stack_depth) {
207                         fw_err(card, "topology stack underflow\n");
208                         return NULL;
209                 }
210
211                 /*
212                  * Seek back from the top of our stack to find the
213                  * start of the child nodes for this node.
214                  */
215                 for (i = 0, h = &stack; i < child_port_count; i++)
216                         h = h->prev;
217                 /*
218                  * When the stack is empty, this yields an invalid value,
219                  * but that pointer will never be dereferenced.
220                  */
221                 child = fw_node(h);
222
223                 node = fw_node_create(q, port_count, card->color);
224                 if (node == NULL) {
225                         fw_err(card, "out of memory while building topology\n");
226                         return NULL;
227                 }
228
229                 if (phy_id == (card->node_id & 0x3f))
230                         local_node = node;
231
232                 if (SELF_ID_CONTENDER(q))
233                         irm_node = node;
234
235                 parent_count = 0;
236
237                 for (i = 0; i < port_count; i++) {
238                         switch (get_port_type(sid, i)) {
239                         case SELFID_PORT_PARENT:
240                                 /*
241                                  * Who's your daddy?  We dont know the
242                                  * parent node at this time, so we
243                                  * temporarily abuse node->color for
244                                  * remembering the entry in the
245                                  * node->ports array where the parent
246                                  * node should be.  Later, when we
247                                  * handle the parent node, we fix up
248                                  * the reference.
249                                  */
250                                 parent_count++;
251                                 node->color = i;
252                                 break;
253
254                         case SELFID_PORT_CHILD:
255                                 node->ports[i] = child;
256                                 /*
257                                  * Fix up parent reference for this
258                                  * child node.
259                                  */
260                                 child->ports[child->color] = node;
261                                 child->color = card->color;
262                                 child = fw_node(child->link.next);
263                                 break;
264                         }
265                 }
266
267                 /*
268                  * Check that the node reports exactly one parent
269                  * port, except for the root, which of course should
270                  * have no parents.
271                  */
272                 if ((next_sid == end && parent_count != 0) ||
273                     (next_sid < end && parent_count != 1)) {
274                         fw_err(card, "parent port inconsistency for node %d: "
275                                "parent_count=%d\n", phy_id, parent_count);
276                         return NULL;
277                 }
278
279                 /* Pop the child nodes off the stack and push the new node. */
280                 __list_del(h->prev, &stack);
281                 list_add_tail(&node->link, &stack);
282                 stack_depth += 1 - child_port_count;
283
284                 if (node->phy_speed == SCODE_BETA &&
285                     parent_count + child_port_count > 1)
286                         beta_repeaters_present = true;
287
288                 /*
289                  * If PHYs report different gap counts, set an invalid count
290                  * which will force a gap count reconfiguration and a reset.
291                  */
292                 if (SELF_ID_GAP_COUNT(q) != gap_count)
293                         gap_count = 0;
294
295                 update_hop_count(node);
296
297                 sid = next_sid;
298                 phy_id++;
299         }
300
301         card->root_node = node;
302         card->irm_node = irm_node;
303         card->gap_count = gap_count;
304         card->beta_repeaters_present = beta_repeaters_present;
305
306         return local_node;
307 }
308
309 typedef void (*fw_node_callback_t)(struct fw_card * card,
310                                    struct fw_node * node,
311                                    struct fw_node * parent);
312
313 static void for_each_fw_node(struct fw_card *card, struct fw_node *root,
314                              fw_node_callback_t callback)
315 {
316         struct list_head list;
317         struct fw_node *node, *next, *child, *parent;
318         int i;
319
320         INIT_LIST_HEAD(&list);
321
322         fw_node_get(root);
323         list_add_tail(&root->link, &list);
324         parent = NULL;
325         list_for_each_entry(node, &list, link) {
326                 node->color = card->color;
327
328                 for (i = 0; i < node->port_count; i++) {
329                         child = node->ports[i];
330                         if (!child)
331                                 continue;
332                         if (child->color == card->color)
333                                 parent = child;
334                         else {
335                                 fw_node_get(child);
336                                 list_add_tail(&child->link, &list);
337                         }
338                 }
339
340                 callback(card, node, parent);
341         }
342
343         list_for_each_entry_safe(node, next, &list, link)
344                 fw_node_put(node);
345 }
346
347 static void report_lost_node(struct fw_card *card,
348                              struct fw_node *node, struct fw_node *parent)
349 {
350         fw_node_event(card, node, FW_NODE_DESTROYED);
351         fw_node_put(node);
352
353         /* Topology has changed - reset bus manager retry counter */
354         card->bm_retries = 0;
355 }
356
357 static void report_found_node(struct fw_card *card,
358                               struct fw_node *node, struct fw_node *parent)
359 {
360         int b_path = (node->phy_speed == SCODE_BETA);
361
362         if (parent != NULL) {
363                 /* min() macro doesn't work here with gcc 3.4 */
364                 node->max_speed = parent->max_speed < node->phy_speed ?
365                                         parent->max_speed : node->phy_speed;
366                 node->b_path = parent->b_path && b_path;
367         } else {
368                 node->max_speed = node->phy_speed;
369                 node->b_path = b_path;
370         }
371
372         fw_node_event(card, node, FW_NODE_CREATED);
373
374         /* Topology has changed - reset bus manager retry counter */
375         card->bm_retries = 0;
376 }
377
378 void fw_destroy_nodes(struct fw_card *card)
379 {
380         unsigned long flags;
381
382         spin_lock_irqsave(&card->lock, flags);
383         card->color++;
384         if (card->local_node != NULL)
385                 for_each_fw_node(card, card->local_node, report_lost_node);
386         card->local_node = NULL;
387         spin_unlock_irqrestore(&card->lock, flags);
388 }
389
390 static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
391 {
392         struct fw_node *tree;
393         int i;
394
395         tree = node1->ports[port];
396         node0->ports[port] = tree;
397         for (i = 0; i < tree->port_count; i++) {
398                 if (tree->ports[i] == node1) {
399                         tree->ports[i] = node0;
400                         break;
401                 }
402         }
403 }
404
405 /*
406  * Compare the old topology tree for card with the new one specified by root.
407  * Queue the nodes and mark them as either found, lost or updated.
408  * Update the nodes in the card topology tree as we go.
409  */
410 static void update_tree(struct fw_card *card, struct fw_node *root)
411 {
412         struct list_head list0, list1;
413         struct fw_node *node0, *node1, *next1;
414         int i, event;
415
416         INIT_LIST_HEAD(&list0);
417         list_add_tail(&card->local_node->link, &list0);
418         INIT_LIST_HEAD(&list1);
419         list_add_tail(&root->link, &list1);
420
421         node0 = fw_node(list0.next);
422         node1 = fw_node(list1.next);
423
424         while (&node0->link != &list0) {
425                 WARN_ON(node0->port_count != node1->port_count);
426
427                 if (node0->link_on && !node1->link_on)
428                         event = FW_NODE_LINK_OFF;
429                 else if (!node0->link_on && node1->link_on)
430                         event = FW_NODE_LINK_ON;
431                 else if (node1->initiated_reset && node1->link_on)
432                         event = FW_NODE_INITIATED_RESET;
433                 else
434                         event = FW_NODE_UPDATED;
435
436                 node0->node_id = node1->node_id;
437                 node0->color = card->color;
438                 node0->link_on = node1->link_on;
439                 node0->initiated_reset = node1->initiated_reset;
440                 node0->max_hops = node1->max_hops;
441                 node1->color = card->color;
442                 fw_node_event(card, node0, event);
443
444                 if (card->root_node == node1)
445                         card->root_node = node0;
446                 if (card->irm_node == node1)
447                         card->irm_node = node0;
448
449                 for (i = 0; i < node0->port_count; i++) {
450                         if (node0->ports[i] && node1->ports[i]) {
451                                 /*
452                                  * This port didn't change, queue the
453                                  * connected node for further
454                                  * investigation.
455                                  */
456                                 if (node0->ports[i]->color == card->color)
457                                         continue;
458                                 list_add_tail(&node0->ports[i]->link, &list0);
459                                 list_add_tail(&node1->ports[i]->link, &list1);
460                         } else if (node0->ports[i]) {
461                                 /*
462                                  * The nodes connected here were
463                                  * unplugged; unref the lost nodes and
464                                  * queue FW_NODE_LOST callbacks for
465                                  * them.
466                                  */
467
468                                 for_each_fw_node(card, node0->ports[i],
469                                                  report_lost_node);
470                                 node0->ports[i] = NULL;
471                         } else if (node1->ports[i]) {
472                                 /*
473                                  * One or more node were connected to
474                                  * this port. Move the new nodes into
475                                  * the tree and queue FW_NODE_CREATED
476                                  * callbacks for them.
477                                  */
478                                 move_tree(node0, node1, i);
479                                 for_each_fw_node(card, node0->ports[i],
480                                                  report_found_node);
481                         }
482                 }
483
484                 node0 = fw_node(node0->link.next);
485                 next1 = fw_node(node1->link.next);
486                 fw_node_put(node1);
487                 node1 = next1;
488         }
489 }
490
491 static void update_topology_map(struct fw_card *card,
492                                 u32 *self_ids, int self_id_count)
493 {
494         int node_count = (card->root_node->node_id & 0x3f) + 1;
495         __be32 *map = card->topology_map;
496
497         *map++ = cpu_to_be32((self_id_count + 2) << 16);
498         *map++ = cpu_to_be32(be32_to_cpu(card->topology_map[1]) + 1);
499         *map++ = cpu_to_be32((node_count << 16) | self_id_count);
500
501         while (self_id_count--)
502                 *map++ = cpu_to_be32p(self_ids++);
503
504         fw_compute_block_crc(card->topology_map);
505 }
506
507 void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,
508                               int self_id_count, u32 *self_ids, bool bm_abdicate)
509 {
510         struct fw_node *local_node;
511         unsigned long flags;
512
513         /*
514          * If the selfID buffer is not the immediate successor of the
515          * previously processed one, we cannot reliably compare the
516          * old and new topologies.
517          */
518         if (!is_next_generation(generation, card->generation) &&
519             card->local_node != NULL) {
520                 fw_destroy_nodes(card);
521                 card->bm_retries = 0;
522         }
523
524         spin_lock_irqsave(&card->lock, flags);
525
526         card->broadcast_channel_allocated = card->broadcast_channel_auto_allocated;
527         card->node_id = node_id;
528         /*
529          * Update node_id before generation to prevent anybody from using
530          * a stale node_id together with a current generation.
531          */
532         smp_wmb();
533         card->generation = generation;
534         card->reset_jiffies = get_jiffies_64();
535         card->bm_node_id  = 0xffff;
536         card->bm_abdicate = bm_abdicate;
537         fw_schedule_bm_work(card, 0);
538
539         local_node = build_tree(card, self_ids, self_id_count);
540
541         update_topology_map(card, self_ids, self_id_count);
542
543         card->color++;
544
545         if (local_node == NULL) {
546                 fw_err(card, "topology build failed\n");
547                 /* FIXME: We need to issue a bus reset in this case. */
548         } else if (card->local_node == NULL) {
549                 card->local_node = local_node;
550                 for_each_fw_node(card, local_node, report_found_node);
551         } else {
552                 update_tree(card, local_node);
553         }
554
555         spin_unlock_irqrestore(&card->lock, flags);
556 }
557 EXPORT_SYMBOL(fw_core_handle_bus_reset);