drivers/firewire/fw-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/module.h>
  22 #include <linux/wait.h>
  23 #include <linux/errno.h>
  24 #include <asm/bug.h>
  25 #include <asm/system.h>
  26 #include "fw-transaction.h"
  27 #include "fw-topology.h"
  28
  29 #define SELF_ID_PHY_ID(q)               (((q) >> 24) & 0x3f)
  30 #define SELF_ID_EXTENDED(q)             (((q) >> 23) & 0x01)
  31 #define SELF_ID_LINK_ON(q)              (((q) >> 22) & 0x01)
  32 #define SELF_ID_GAP_COUNT(q)            (((q) >> 16) & 0x3f)
  33 #define SELF_ID_PHY_SPEED(q)            (((q) >> 14) & 0x03)
  34 #define SELF_ID_CONTENDER(q)            (((q) >> 11) & 0x01)
  35 #define SELF_ID_PHY_INITIATOR(q)        (((q) >>  1) & 0x01)
  36 #define SELF_ID_MORE_PACKETS(q)         (((q) >>  0) & 0x01)
  37
  38 #define SELF_ID_EXT_SEQUENCE(q)         (((q) >> 20) & 0x07)
  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                 case SELFID_PORT_PARENT:
  58                 case SELFID_PORT_NCONN:
  59                         (*total_port_count)++;
  60                 case SELFID_PORT_NONE:
  61                         break;
  62                 }
  63
  64                 shift -= 2;
  65                 if (shift == 0) {
  66                         if (!SELF_ID_MORE_PACKETS(q))
  67                                 return sid + 1;
  68
  69                         shift = 16;
  70                         sid++;
  71                         q = *sid;
  72
  73                         /*
  74                          * Check that the extra packets actually are
  75                          * extended self ID packets and that the
  76                          * sequence numbers in the extended self ID
  77                          * packets increase as expected.
  78                          */
  79
  80                         if (!SELF_ID_EXTENDED(q) ||
  81                             seq != SELF_ID_EXT_SEQUENCE(q))
  82                                 return NULL;
  83
  84                         seq++;
  85                 }
  86         }
  87 }
  88
  89 static int get_port_type(u32 *sid, int port_index)
  90 {
  91         int index, shift;
  92
  93         index = (port_index + 5) / 8;
  94         shift = 16 - ((port_index + 5) & 7) * 2;
  95         return (sid[index] >> shift) & 0x03;
  96 }
  97
  98 static struct fw_node *fw_node_create(u32 sid, int port_count, int color)
  99 {
 100         struct fw_node *node;
 101
 102         node = kzalloc(sizeof(*node) + port_count * sizeof(node->ports[0]),
 103                        GFP_ATOMIC);
 104         if (node == NULL)
 105                 return NULL;
 106
 107         node->color = color;
 108         node->node_id = LOCAL_BUS | SELF_ID_PHY_ID(sid);
 109         node->link_on = SELF_ID_LINK_ON(sid);
 110         node->phy_speed = SELF_ID_PHY_SPEED(sid);
 111         node->initiated_reset = SELF_ID_PHY_INITIATOR(sid);
 112         node->port_count = port_count;
 113
 114         atomic_set(&node->ref_count, 1);
 115         INIT_LIST_HEAD(&node->link);
 116
 117         return node;
 118 }
 119
 120 /*
 121  * Compute the maximum hop count for this node and it's children.  The
 122  * maximum hop count is the maximum number of connections between any
 123  * two nodes in the subtree rooted at this node.  We need this for
 124  * setting the gap count.  As we build the tree bottom up in
 125  * build_tree() below, this is fairly easy to do: for each node we
 126  * maintain the max hop count and the max depth, ie the number of hops
 127  * to the furthest leaf.  Computing the max hop count breaks down into
 128  * two cases: either the path goes through this node, in which case
 129  * the hop count is the sum of the two biggest child depths plus 2.
 130  * Or it could be the case that the max hop path is entirely
 131  * containted in a child tree, in which case the max hop count is just
 132  * the max hop count of this child.
 133  */
 134 static void update_hop_count(struct fw_node *node)
 135 {
 136         int depths[2] = { -1, -1 };
 137         int max_child_hops = 0;
 138         int i;
 139
 140         for (i = 0; i < node->port_count; i++) {
 141                 if (node->ports[i] == NULL)
 142                         continue;
 143
 144                 if (node->ports[i]->max_hops > max_child_hops)
 145                         max_child_hops = node->ports[i]->max_hops;
 146
 147                 if (node->ports[i]->max_depth > depths[0]) {
 148                         depths[1] = depths[0];
 149                         depths[0] = node->ports[i]->max_depth;
 150                 } else if (node->ports[i]->max_depth > depths[1])
 151                         depths[1] = node->ports[i]->max_depth;
 152         }
 153
 154         node->max_depth = depths[0] + 1;
 155         node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2);
 156 }
 157
 158 static inline struct fw_node *fw_node(struct list_head *l)
 159 {
 160         return list_entry(l, struct fw_node, link);
 161 }
 162
 163 /**
 164  * build_tree - Build the tree representation of the topology
 165  * @self_ids: array of self IDs to create the tree from
 166  * @self_id_count: the length of the self_ids array
 167  * @local_id: the node ID of the local node
 168  *
 169  * This function builds the tree representation of the topology given
 170  * by the self IDs from the latest bus reset.  During the construction
 171  * of the tree, the function checks that the self IDs are valid and
 172  * internally consistent.  On succcess this function returns the
 173  * fw_node corresponding to the local card otherwise NULL.
 174  */
 175 static struct fw_node *build_tree(struct fw_card *card,
 176                                   u32 *sid, int self_id_count)
 177 {
 178         struct fw_node *node, *child, *local_node, *irm_node;
 179         struct list_head stack, *h;
 180         u32 *next_sid, *end, q;
 181         int i, port_count, child_port_count, phy_id, parent_count, stack_depth;
 182         int gap_count;
 183         bool beta_repeaters_present;
 184
 185         local_node = NULL;
 186         node = NULL;
 187         INIT_LIST_HEAD(&stack);
 188         stack_depth = 0;
 189         end = sid + self_id_count;
 190         phy_id = 0;
 191         irm_node = NULL;
 192         gap_count = SELF_ID_GAP_COUNT(*sid);
 193         beta_repeaters_present = false;
 194
 195         while (sid < end) {
 196                 next_sid = count_ports(sid, &port_count, &child_port_count);
 197
 198                 if (next_sid == NULL) {
 199                         fw_error("Inconsistent extended self IDs.\n");
 200                         return NULL;
 201                 }
 202
 203                 q = *sid;
 204                 if (phy_id != SELF_ID_PHY_ID(q)) {
 205                         fw_error("PHY ID mismatch in self ID: %d != %d.\n",
 206                                  phy_id, SELF_ID_PHY_ID(q));
 207                         return NULL;
 208                 }
 209
 210                 if (child_port_count > stack_depth) {
 211                         fw_error("Topology stack underflow\n");
 212                         return NULL;
 213                 }
 214
 215                 /*
 216                  * Seek back from the top of our stack to find the
 217                  * start of the child nodes for this node.
 218                  */
 219                 for (i = 0, h = &stack; i < child_port_count; i++)
 220                         h = h->prev;
 221                 /*
 222                  * When the stack is empty, this yields an invalid value,
 223                  * but that pointer will never be dereferenced.
 224                  */
 225                 child = fw_node(h);
 226
 227                 node = fw_node_create(q, port_count, card->color);
 228                 if (node == NULL) {
 229                         fw_error("Out of memory while building topology.\n");
 230                         return NULL;
 231                 }
 232
 233                 if (phy_id == (card->node_id & 0x3f))
 234                         local_node = node;
 235
 236                 if (SELF_ID_CONTENDER(q))
 237                         irm_node = node;
 238
 239                 parent_count = 0;
 240
 241                 for (i = 0; i < port_count; i++) {
 242                         switch (get_port_type(sid, i)) {
 243                         case SELFID_PORT_PARENT:
 244                                 /*
 245                                  * Who's your daddy?  We dont know the
 246                                  * parent node at this time, so we
 247                                  * temporarily abuse node->color for
 248                                  * remembering the entry in the
 249                                  * node->ports array where the parent
 250                                  * node should be.  Later, when we
 251                                  * handle the parent node, we fix up
 252                                  * the reference.
 253                                  */
 254                                 parent_count++;
 255                                 node->color = i;
 256                                 break;
 257
 258                         case SELFID_PORT_CHILD:
 259                                 node->ports[i] = child;
 260                                 /*
 261                                  * Fix up parent reference for this
 262                                  * child node.
 263                                  */
 264                                 child->ports[child->color] = node;
 265                                 child->color = card->color;
 266                                 child = fw_node(child->link.next);
 267                                 break;
 268                         }
 269                 }
 270
 271                 /*
 272                  * Check that the node reports exactly one parent
 273                  * port, except for the root, which of course should
 274                  * have no parents.
 275                  */
 276                 if ((next_sid == end && parent_count != 0) ||
 277                     (next_sid < end && parent_count != 1)) {
 278                         fw_error("Parent port inconsistency for node %d: "
 279                                  "parent_count=%d\n", phy_id, parent_count);
 280                         return NULL;
 281                 }
 282
 283                 /* Pop the child nodes off the stack and push the new node. */
 284                 __list_del(h->prev, &stack);
 285                 list_add_tail(&node->link, &stack);
 286                 stack_depth += 1 - child_port_count;
 287
 288                 if (node->phy_speed == SCODE_BETA &&
 289                     parent_count + child_port_count > 1)
 290                         beta_repeaters_present = true;
 291
 292                 /*
 293                  * If PHYs report different gap counts, set an invalid count
 294                  * which will force a gap count reconfiguration and a reset.
 295                  */
 296                 if (SELF_ID_GAP_COUNT(q) != gap_count)
 297                         gap_count = 0;
 298
 299                 update_hop_count(node);
 300
 301                 sid = next_sid;
 302                 phy_id++;
 303         }
 304
 305         card->root_node = node;
 306         card->irm_node = irm_node;
 307         card->gap_count = gap_count;
 308         card->beta_repeaters_present = beta_repeaters_present;
 309
 310         return local_node;
 311 }
 312
 313 typedef void (*fw_node_callback_t)(struct fw_card * card,
 314                                    struct fw_node * node,
 315                                    struct fw_node * parent);
 316
 317 static void
 318 for_each_fw_node(struct fw_card *card, struct fw_node *root,
 319                  fw_node_callback_t callback)
 320 {
 321         struct list_head list;
 322         struct fw_node *node, *next, *child, *parent;
 323         int i;
 324
 325         INIT_LIST_HEAD(&list);
 326
 327         fw_node_get(root);
 328         list_add_tail(&root->link, &list);
 329         parent = NULL;
 330         list_for_each_entry(node, &list, link) {
 331                 node->color = card->color;
 332
 333                 for (i = 0; i < node->port_count; i++) {
 334                         child = node->ports[i];
 335                         if (!child)
 336                                 continue;
 337                         if (child->color == card->color)
 338                                 parent = child;
 339                         else {
 340                                 fw_node_get(child);
 341                                 list_add_tail(&child->link, &list);
 342                         }
 343                 }
 344
 345                 callback(card, node, parent);
 346         }
 347
 348         list_for_each_entry_safe(node, next, &list, link)
 349                 fw_node_put(node);
 350 }
 351
 352 static void
 353 report_lost_node(struct fw_card *card,
 354                  struct fw_node *node, struct fw_node *parent)
 355 {
 356         fw_node_event(card, node, FW_NODE_DESTROYED);
 357         fw_node_put(node);
 358
 359         /* Topology has changed - reset bus manager retry counter */
 360         card->bm_retries = 0;
 361 }
 362
 363 static void
 364 report_found_node(struct fw_card *card,
 365                   struct fw_node *node, struct fw_node *parent)
 366 {
 367         int b_path = (node->phy_speed == SCODE_BETA);
 368
 369         if (parent != NULL) {
 370                 /* min() macro doesn't work here with gcc 3.4 */
 371                 node->max_speed = parent->max_speed < node->phy_speed ?
 372                                         parent->max_speed : node->phy_speed;
 373                 node->b_path = parent->b_path && b_path;
 374         } else {
 375                 node->max_speed = node->phy_speed;
 376                 node->b_path = b_path;
 377         }
 378
 379         fw_node_event(card, node, FW_NODE_CREATED);
 380
 381         /* Topology has changed - reset bus manager retry counter */
 382         card->bm_retries = 0;
 383 }
 384
 385 void fw_destroy_nodes(struct fw_card *card)
 386 {
 387         unsigned long flags;
 388
 389         spin_lock_irqsave(&card->lock, flags);
 390         card->color++;
 391         if (card->local_node != NULL)
 392                 for_each_fw_node(card, card->local_node, report_lost_node);
 393         card->local_node = NULL;
 394         spin_unlock_irqrestore(&card->lock, flags);
 395 }
 396
 397 static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
 398 {
 399         struct fw_node *tree;
 400         int i;
 401
 402         tree = node1->ports[port];
 403         node0->ports[port] = tree;
 404         for (i = 0; i < tree->port_count; i++) {
 405                 if (tree->ports[i] == node1) {
 406                         tree->ports[i] = node0;
 407                         break;
 408                 }
 409         }
 410 }
 411
 412 /**
 413  * update_tree - compare the old topology tree for card with the new
 414  * one specified by root.  Queue the nodes and mark them as either
 415  * found, lost or updated.  Update the nodes in the card topology tree
 416  * as we go.
 417  */
 418 static void
 419 update_tree(struct fw_card *card, struct fw_node *root)
 420 {
 421         struct list_head list0, list1;
 422         struct fw_node *node0, *node1, *next1;
 423         int i, event;
 424
 425         INIT_LIST_HEAD(&list0);
 426         list_add_tail(&card->local_node->link, &list0);
 427         INIT_LIST_HEAD(&list1);
 428         list_add_tail(&root->link, &list1);
 429
 430         node0 = fw_node(list0.next);
 431         node1 = fw_node(list1.next);
 432
 433         while (&node0->link != &list0) {
 434                 WARN_ON(node0->port_count != node1->port_count);
 435
 436                 if (node0->link_on && !node1->link_on)
 437                         event = FW_NODE_LINK_OFF;
 438                 else if (!node0->link_on && node1->link_on)
 439                         event = FW_NODE_LINK_ON;
 440                 else if (node1->initiated_reset && node1->link_on)
 441                         event = FW_NODE_INITIATED_RESET;
 442                 else
 443                         event = FW_NODE_UPDATED;
 444
 445                 node0->node_id = node1->node_id;
 446                 node0->color = card->color;
 447                 node0->link_on = node1->link_on;
 448                 node0->initiated_reset = node1->initiated_reset;
 449                 node0->max_hops = node1->max_hops;
 450                 node1->color = card->color;
 451                 fw_node_event(card, node0, event);
 452
 453                 if (card->root_node == node1)
 454                         card->root_node = node0;
 455                 if (card->irm_node == node1)
 456                         card->irm_node = node0;
 457
 458                 for (i = 0; i < node0->port_count; i++) {
 459                         if (node0->ports[i] && node1->ports[i]) {
 460                                 /*
 461                                  * This port didn't change, queue the
 462                                  * connected node for further
 463                                  * investigation.
 464                                  */
 465                                 if (node0->ports[i]->color == card->color)
 466                                         continue;
 467                                 list_add_tail(&node0->ports[i]->link, &list0);
 468                                 list_add_tail(&node1->ports[i]->link, &list1);
 469                         } else if (node0->ports[i]) {
 470                                 /*
 471                                  * The nodes connected here were
 472                                  * unplugged; unref the lost nodes and
 473                                  * queue FW_NODE_LOST callbacks for
 474                                  * them.
 475                                  */
 476
 477                                 for_each_fw_node(card, node0->ports[i],
 478                                                  report_lost_node);
 479                                 node0->ports[i] = NULL;
 480                         } else if (node1->ports[i]) {
 481                                 /*
 482                                  * One or more node were connected to
 483                                  * this port. Move the new nodes into
 484                                  * the tree and queue FW_NODE_CREATED
 485                                  * callbacks for them.
 486                                  */
 487                                 move_tree(node0, node1, i);
 488                                 for_each_fw_node(card, node0->ports[i],
 489                                                  report_found_node);
 490                         }
 491                 }
 492
 493                 node0 = fw_node(node0->link.next);
 494                 next1 = fw_node(node1->link.next);
 495                 fw_node_put(node1);
 496                 node1 = next1;
 497         }
 498 }
 499
 500 static void
 501 update_topology_map(struct fw_card *card, u32 *self_ids, int self_id_count)
 502 {
 503         int node_count;
 504
 505         card->topology_map[1]++;
 506         node_count = (card->root_node->node_id & 0x3f) + 1;
 507         card->topology_map[2] = (node_count << 16) | self_id_count;
 508         card->topology_map[0] = (self_id_count + 2) << 16;
 509         memcpy(&card->topology_map[3], self_ids, self_id_count * 4);
 510         fw_compute_block_crc(card->topology_map);
 511 }
 512
 513 void
 514 fw_core_handle_bus_reset(struct fw_card *card,
 515                          int node_id, int generation,
 516                          int self_id_count, u32 * self_ids)
 517 {
 518         struct fw_node *local_node;
 519         unsigned long flags;
 520
 521         /*
 522          * If the selfID buffer is not the immediate successor of the
 523          * previously processed one, we cannot reliably compare the
 524          * old and new topologies.
 525          */
 526         if (!is_next_generation(generation, card->generation) &&
 527             card->local_node != NULL) {
 528                 fw_notify("skipped bus generations, destroying all nodes\n");
 529                 fw_destroy_nodes(card);
 530                 card->bm_retries = 0;
 531         }
 532
 533         spin_lock_irqsave(&card->lock, flags);
 534
 535         card->node_id = node_id;
 536         /*
 537          * Update node_id before generation to prevent anybody from using
 538          * a stale node_id together with a current generation.
 539          */
 540         smp_wmb();
 541         card->generation = generation;
 542         card->reset_jiffies = jiffies;
 543         fw_schedule_bm_work(card, 0);
 544
 545         local_node = build_tree(card, self_ids, self_id_count);
 546
 547         update_topology_map(card, self_ids, self_id_count);
 548
 549         card->color++;
 550
 551         if (local_node == NULL) {
 552                 fw_error("topology build failed\n");
 553                 /* FIXME: We need to issue a bus reset in this case. */
 554         } else if (card->local_node == NULL) {
 555                 card->local_node = local_node;
 556                 for_each_fw_node(card, local_node, report_found_node);
 557         } else {
 558                 update_tree(card, local_node);
 559         }
 560
 561         spin_unlock_irqrestore(&card->lock, flags);
 562 }
 563 EXPORT_SYMBOL(fw_core_handle_bus_reset);