drivers/firewire/core-topology.c

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