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/system.h>
  25 #include "fw-transaction.h"
  26 #include "fw-topology.h"
  27
  28 #define SELF_ID_PHY_ID(q)               (((q) >> 24) & 0x3f)
  29 #define SELF_ID_EXTENDED(q)             (((q) >> 23) & 0x01)
  30 #define SELF_ID_LINK_ON(q)              (((q) >> 22) & 0x01)
  31 #define SELF_ID_GAP_COUNT(q)            (((q) >> 16) & 0x3f)
  32 #define SELF_ID_PHY_SPEED(q)            (((q) >> 14) & 0x03)
  33 #define SELF_ID_CONTENDER(q)            (((q) >> 11) & 0x01)
  34 #define SELF_ID_PHY_INITIATOR(q)        (((q) >>  1) & 0x01)
  35 #define SELF_ID_MORE_PACKETS(q)         (((q) >>  0) & 0x01)
  36
  37 #define SELF_ID_EXT_SEQUENCE(q)         (((q) >> 20) & 0x07)
  38
  39 static u32 *count_ports(u32 *sid, int *total_port_count, int *child_port_count)
  40 {
  41         u32 q;
  42         int port_type, shift, seq;
  43
  44         *total_port_count = 0;
  45         *child_port_count = 0;
  46
  47         shift = 6;
  48         q = *sid;
  49         seq = 0;
  50
  51         while (1) {
  52                 port_type = (q >> shift) & 0x03;
  53                 switch (port_type) {
  54                 case SELFID_PORT_CHILD:
  55                         (*child_port_count)++;
  56                 case SELFID_PORT_PARENT:
  57                 case SELFID_PORT_NCONN:
  58                         (*total_port_count)++;
  59                 case SELFID_PORT_NONE:
  60                         break;
  61                 }
  62
  63                 shift -= 2;
  64                 if (shift == 0) {
  65                         if (!SELF_ID_MORE_PACKETS(q))
  66                                 return sid + 1;
  67
  68                         shift = 16;
  69                         sid++;
  70                         q = *sid;
  71
  72                         /*
  73                          * Check that the extra packets actually are
  74                          * extended self ID packets and that the
  75                          * sequence numbers in the extended self ID
  76                          * packets increase as expected.
  77                          */
  78
  79                         if (!SELF_ID_EXTENDED(q) ||
  80                             seq != SELF_ID_EXT_SEQUENCE(q))
  81                                 return NULL;
  82
  83                         seq++;
  84                 }
  85         }
  86 }
  87
  88 static int get_port_type(u32 *sid, int port_index)
  89 {
  90         int index, shift;
  91
  92         index = (port_index + 5) / 8;
  93         shift = 16 - ((port_index + 5) & 7) * 2;
  94         return (sid[index] >> shift) & 0x03;
  95 }
  96
  97 static struct fw_node *fw_node_create(u32 sid, int port_count, int color)
  98 {
  99         struct fw_node *node;
 100
 101         node = kzalloc(sizeof(*node) + port_count * sizeof(node->ports[0]),
 102                        GFP_ATOMIC);
 103         if (node == NULL)
 104                 return NULL;
 105
 106         node->color = color;
 107         node->node_id = LOCAL_BUS | SELF_ID_PHY_ID(sid);
 108         node->link_on = SELF_ID_LINK_ON(sid);
 109         node->phy_speed = SELF_ID_PHY_SPEED(sid);
 110         node->port_count = port_count;
 111
 112         atomic_set(&node->ref_count, 1);
 113         INIT_LIST_HEAD(&node->link);
 114
 115         return node;
 116 }
 117
 118 /*
 119  * Compute the maximum hop count for this node and it's children.  The
 120  * maximum hop count is the maximum number of connections between any
 121  * two nodes in the subtree rooted at this node.  We need this for
 122  * setting the gap count.  As we build the tree bottom up in
 123  * build_tree() below, this is fairly easy to do: for each node we
 124  * maintain the max hop count and the max depth, ie the number of hops
 125  * to the furthest leaf.  Computing the max hop count breaks down into
 126  * two cases: either the path goes through this node, in which case
 127  * the hop count is the sum of the two biggest child depths plus 2.
 128  * Or it could be the case that the max hop path is entirely
 129  * containted in a child tree, in which case the max hop count is just
 130  * the max hop count of this child.
 131  */
 132 static void update_hop_count(struct fw_node *node)
 133 {
 134         int depths[2] = { -1, -1 };
 135         int max_child_hops = 0;
 136         int i;
 137
 138         for (i = 0; i < node->port_count; i++) {
 139                 if (node->ports[i] == NULL)
 140                         continue;
 141
 142                 if (node->ports[i]->max_hops > max_child_hops)
 143                         max_child_hops = node->ports[i]->max_hops;
 144
 145                 if (node->ports[i]->max_depth > depths[0]) {
 146                         depths[1] = depths[0];
 147                         depths[0] = node->ports[i]->max_depth;
 148                 } else if (node->ports[i]->max_depth > depths[1])
 149                         depths[1] = node->ports[i]->max_depth;
 150         }
 151
 152         node->max_depth = depths[0] + 1;
 153         node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2);
 154 }
 155
 156 static inline struct fw_node *fw_node(struct list_head *l)
 157 {
 158         return list_entry(l, struct fw_node, link);
 159 }
 160
 161 /**
 162  * build_tree - Build the tree representation of the topology
 163  * @self_ids: array of self IDs to create the tree from
 164  * @self_id_count: the length of the self_ids array
 165  * @local_id: the node ID of the local node
 166  *
 167  * This function builds the tree representation of the topology given
 168  * by the self IDs from the latest bus reset.  During the construction
 169  * of the tree, the function checks that the self IDs are valid and
 170  * internally consistent.  On succcess this function returns the
 171  * fw_node corresponding to the local card otherwise NULL.
 172  */
 173 static struct fw_node *build_tree(struct fw_card *card,
 174                                   u32 *sid, int self_id_count)
 175 {
 176         struct fw_node *node, *child, *local_node, *irm_node;
 177         struct list_head stack, *h;
 178         u32 *next_sid, *end, q;
 179         int i, port_count, child_port_count, phy_id, parent_count, stack_depth;
 180         int gap_count;
 181         bool beta_repeaters_present;
 182
 183         local_node = NULL;
 184         node = NULL;
 185         INIT_LIST_HEAD(&stack);
 186         stack_depth = 0;
 187         end = sid + self_id_count;
 188         phy_id = 0;
 189         irm_node = NULL;
 190         gap_count = SELF_ID_GAP_COUNT(*sid);
 191         beta_repeaters_present = false;
 192
 193         while (sid < end) {
 194                 next_sid = count_ports(sid, &port_count, &child_port_count);
 195
 196                 if (next_sid == NULL) {
 197                         fw_error("Inconsistent extended self IDs.\n");
 198                         return NULL;
 199                 }
 200
 201                 q = *sid;
 202                 if (phy_id != SELF_ID_PHY_ID(q)) {
 203                         fw_error("PHY ID mismatch in self ID: %d != %d.\n",
 204                                  phy_id, SELF_ID_PHY_ID(q));
 205                         return NULL;
 206                 }
 207
 208                 if (child_port_count > stack_depth) {
 209                         fw_error("Topology stack underflow\n");
 210                         return NULL;
 211                 }
 212
 213                 /*
 214                  * Seek back from the top of our stack to find the
 215                  * start of the child nodes for this node.
 216                  */
 217                 for (i = 0, h = &stack; i < child_port_count; i++)
 218                         h = h->prev;
 219                 /*
 220                  * When the stack is empty, this yields an invalid value,
 221                  * but that pointer will never be dereferenced.
 222                  */
 223                 child = fw_node(h);
 224
 225                 node = fw_node_create(q, port_count, card->color);
 226                 if (node == NULL) {
 227                         fw_error("Out of memory while building topology.\n");
 228                         return NULL;
 229                 }
 230
 231                 if (phy_id == (card->node_id & 0x3f))
 232                         local_node = node;
 233
 234                 if (SELF_ID_CONTENDER(q))
 235                         irm_node = node;
 236
 237                 parent_count = 0;
 238
 239                 for (i = 0; i < port_count; i++) {
 240                         switch (get_port_type(sid, i)) {
 241                         case SELFID_PORT_PARENT:
 242                                 /*
 243                                  * Who's your daddy?  We dont know the
 244                                  * parent node at this time, so we
 245                                  * temporarily abuse node->color for
 246                                  * remembering the entry in the
 247                                  * node->ports array where the parent
 248                                  * node should be.  Later, when we
 249                                  * handle the parent node, we fix up
 250                                  * the reference.
 251                                  */
 252                                 parent_count++;
 253                                 node->color = i;
 254                                 break;
 255
 256                         case SELFID_PORT_CHILD:
 257                                 node->ports[i] = child;
 258                                 /*
 259                                  * Fix up parent reference for this
 260                                  * child node.
 261                                  */
 262                                 child->ports[child->color] = node;
 263                                 child->color = card->color;
 264                                 child = fw_node(child->link.next);
 265                                 break;
 266                         }
 267                 }
 268
 269                 /*
 270                  * Check that the node reports exactly one parent
 271                  * port, except for the root, which of course should
 272                  * have no parents.
 273                  */
 274                 if ((next_sid == end && parent_count != 0) ||
 275                     (next_sid < end && parent_count != 1)) {
 276                         fw_error("Parent port inconsistency for node %d: "
 277                                  "parent_count=%d\n", phy_id, parent_count);
 278                         return NULL;
 279                 }
 280
 281                 /* Pop the child nodes off the stack and push the new node. */
 282                 __list_del(h->prev, &stack);
 283                 list_add_tail(&node->link, &stack);
 284                 stack_depth += 1 - child_port_count;
 285
 286                 if (node->phy_speed == SCODE_BETA &&
 287                     parent_count + child_port_count > 1)
 288                         beta_repeaters_present = true;
 289
 290                 /*
 291                  * If all PHYs does not report the same gap count
 292                  * setting, we fall back to 63 which will force a gap
 293                  * count reconfiguration and a reset.
 294                  */
 295                 if (SELF_ID_GAP_COUNT(q) != gap_count)
 296                         gap_count = 63;
 297
 298                 update_hop_count(node);
 299
 300                 sid = next_sid;
 301                 phy_id++;
 302         }
 303
 304         card->root_node = node;
 305         card->irm_node = irm_node;
 306         card->gap_count = gap_count;
 307         card->beta_repeaters_present = beta_repeaters_present;
 308
 309         return local_node;
 310 }
 311
 312 typedef void (*fw_node_callback_t)(struct fw_card * card,
 313                                    struct fw_node * node,
 314                                    struct fw_node * parent);
 315
 316 static void
 317 for_each_fw_node(struct fw_card *card, struct fw_node *root,
 318                  fw_node_callback_t callback)
 319 {
 320         struct list_head list;
 321         struct fw_node *node, *next, *child, *parent;
 322         int i;
 323
 324         INIT_LIST_HEAD(&list);
 325
 326         fw_node_get(root);
 327         list_add_tail(&root->link, &list);
 328         parent = NULL;
 329         list_for_each_entry(node, &list, link) {
 330                 node->color = card->color;
 331
 332                 for (i = 0; i < node->port_count; i++) {
 333                         child = node->ports[i];
 334                         if (!child)
 335                                 continue;
 336                         if (child->color == card->color)
 337                                 parent = child;
 338                         else {
 339                                 fw_node_get(child);
 340                                 list_add_tail(&child->link, &list);
 341                         }
 342                 }
 343
 344                 callback(card, node, parent);
 345         }
 346
 347         list_for_each_entry_safe(node, next, &list, link)
 348                 fw_node_put(node);
 349 }
 350
 351 static void
 352 report_lost_node(struct fw_card *card,
 353                  struct fw_node *node, struct fw_node *parent)
 354 {
 355         fw_node_event(card, node, FW_NODE_DESTROYED);
 356         fw_node_put(node);
 357 }
 358
 359 static void
 360 report_found_node(struct fw_card *card,
 361                   struct fw_node *node, struct fw_node *parent)
 362 {
 363         int b_path = (node->phy_speed == SCODE_BETA);
 364
 365         if (parent != NULL) {
 366                 /* min() macro doesn't work here with gcc 3.4 */
 367                 node->max_speed = parent->max_speed < node->phy_speed ?
 368                                         parent->max_speed : node->phy_speed;
 369                 node->b_path = parent->b_path && b_path;
 370         } else {
 371                 node->max_speed = node->phy_speed;
 372                 node->b_path = b_path;
 373         }
 374
 375         fw_node_event(card, node, FW_NODE_CREATED);
 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  * update_tree - compare the old topology tree for card with the new
 407  * one specified by root.  Queue the nodes and mark them as either
 408  * found, lost or updated.  Update the nodes in the card topology tree
 409  * as we go.
 410  */
 411 static void
 412 update_tree(struct fw_card *card, struct fw_node *root)
 413 {
 414         struct list_head list0, list1;
 415         struct fw_node *node0, *node1;
 416         int i, event;
 417
 418         INIT_LIST_HEAD(&list0);
 419         list_add_tail(&card->local_node->link, &list0);
 420         INIT_LIST_HEAD(&list1);
 421         list_add_tail(&root->link, &list1);
 422
 423         node0 = fw_node(list0.next);
 424         node1 = fw_node(list1.next);
 425
 426         while (&node0->link != &list0) {
 427
 428                 /* assert(node0->port_count == node1->port_count); */
 429                 if (node0->link_on && !node1->link_on)
 430                         event = FW_NODE_LINK_OFF;
 431                 else if (!node0->link_on && node1->link_on)
 432                         event = FW_NODE_LINK_ON;
 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                 node1 = fw_node(node1->link.next);
 486         }
 487 }
 488
 489 static void
 490 update_topology_map(struct fw_card *card, u32 *self_ids, int self_id_count)
 491 {
 492         int node_count;
 493
 494         card->topology_map[1]++;
 495         node_count = (card->root_node->node_id & 0x3f) + 1;
 496         card->topology_map[2] = (node_count << 16) | self_id_count;
 497         card->topology_map[0] = (self_id_count + 2) << 16;
 498         memcpy(&card->topology_map[3], self_ids, self_id_count * 4);
 499         fw_compute_block_crc(card->topology_map);
 500 }
 501
 502 void
 503 fw_core_handle_bus_reset(struct fw_card *card,
 504                          int node_id, int generation,
 505                          int self_id_count, u32 * self_ids)
 506 {
 507         struct fw_node *local_node;
 508         unsigned long flags;
 509
 510         fw_flush_transactions(card);
 511
 512         spin_lock_irqsave(&card->lock, flags);
 513
 514         /*
 515          * If the new topology has a different self_id_count the topology
 516          * changed, either nodes were added or removed. In that case we
 517          * reset the IRM reset counter.
 518          */
 519         if (card->self_id_count != self_id_count)
 520                 card->bm_retries = 0;
 521
 522         card->node_id = node_id;
 523         /*
 524          * Update node_id before generation to prevent anybody from using
 525          * a stale node_id together with a current generation.
 526          */
 527         smp_wmb();
 528         card->generation = generation;
 529         card->reset_jiffies = jiffies;
 530         schedule_delayed_work(&card->work, 0);
 531
 532         local_node = build_tree(card, self_ids, self_id_count);
 533
 534         update_topology_map(card, self_ids, self_id_count);
 535
 536         card->color++;
 537
 538         if (local_node == NULL) {
 539                 fw_error("topology build failed\n");
 540                 /* FIXME: We need to issue a bus reset in this case. */
 541         } else if (card->local_node == NULL) {
 542                 card->local_node = local_node;
 543                 for_each_fw_node(card, local_node, report_found_node);
 544         } else {
 545                 update_tree(card, local_node);
 546         }
 547
 548         spin_unlock_irqrestore(&card->lock, flags);
 549 }
 550 EXPORT_SYMBOL(fw_core_handle_bus_reset);