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->port_count = port_count;
 112
 113         atomic_set(&node->ref_count, 1);
 114         INIT_LIST_HEAD(&node->link);
 115
 116         return node;
 117 }
 118
 119 /*
 120  * Compute the maximum hop count for this node and it's children.  The
 121  * maximum hop count is the maximum number of connections between any
 122  * two nodes in the subtree rooted at this node.  We need this for
 123  * setting the gap count.  As we build the tree bottom up in
 124  * build_tree() below, this is fairly easy to do: for each node we
 125  * maintain the max hop count and the max depth, ie the number of hops
 126  * to the furthest leaf.  Computing the max hop count breaks down into
 127  * two cases: either the path goes through this node, in which case
 128  * the hop count is the sum of the two biggest child depths plus 2.
 129  * Or it could be the case that the max hop path is entirely
 130  * containted in a child tree, in which case the max hop count is just
 131  * the max hop count of this child.
 132  */
 133 static void update_hop_count(struct fw_node *node)
 134 {
 135         int depths[2] = { -1, -1 };
 136         int max_child_hops = 0;
 137         int i;
 138
 139         for (i = 0; i < node->port_count; i++) {
 140                 if (node->ports[i] == NULL)
 141                         continue;
 142
 143                 if (node->ports[i]->max_hops > max_child_hops)
 144                         max_child_hops = node->ports[i]->max_hops;
 145
 146                 if (node->ports[i]->max_depth > depths[0]) {
 147                         depths[1] = depths[0];
 148                         depths[0] = node->ports[i]->max_depth;
 149                 } else if (node->ports[i]->max_depth > depths[1])
 150                         depths[1] = node->ports[i]->max_depth;
 151         }
 152
 153         node->max_depth = depths[0] + 1;
 154         node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2);
 155 }
 156
 157 static inline struct fw_node *fw_node(struct list_head *l)
 158 {
 159         return list_entry(l, struct fw_node, link);
 160 }
 161
 162 /**
 163  * build_tree - Build the tree representation of the topology
 164  * @self_ids: array of self IDs to create the tree from
 165  * @self_id_count: the length of the self_ids array
 166  * @local_id: the node ID of the local node
 167  *
 168  * This function builds the tree representation of the topology given
 169  * by the self IDs from the latest bus reset.  During the construction
 170  * of the tree, the function checks that the self IDs are valid and
 171  * internally consistent.  On succcess this function returns the
 172  * fw_node corresponding to the local card otherwise NULL.
 173  */
 174 static struct fw_node *build_tree(struct fw_card *card,
 175                                   u32 *sid, int self_id_count)
 176 {
 177         struct fw_node *node, *child, *local_node, *irm_node;
 178         struct list_head stack, *h;
 179         u32 *next_sid, *end, q;
 180         int i, port_count, child_port_count, phy_id, parent_count, stack_depth;
 181         int gap_count;
 182         bool beta_repeaters_present;
 183
 184         local_node = NULL;
 185         node = NULL;
 186         INIT_LIST_HEAD(&stack);
 187         stack_depth = 0;
 188         end = sid + self_id_count;
 189         phy_id = 0;
 190         irm_node = NULL;
 191         gap_count = SELF_ID_GAP_COUNT(*sid);
 192         beta_repeaters_present = false;
 193
 194         while (sid < end) {
 195                 next_sid = count_ports(sid, &port_count, &child_port_count);
 196
 197                 if (next_sid == NULL) {
 198                         fw_error("Inconsistent extended self IDs.\n");
 199                         return NULL;
 200                 }
 201
 202                 q = *sid;
 203                 if (phy_id != SELF_ID_PHY_ID(q)) {
 204                         fw_error("PHY ID mismatch in self ID: %d != %d.\n",
 205                                  phy_id, SELF_ID_PHY_ID(q));
 206                         return NULL;
 207                 }
 208
 209                 if (child_port_count > stack_depth) {
 210                         fw_error("Topology stack underflow\n");
 211                         return NULL;
 212                 }
 213
 214                 /*
 215                  * Seek back from the top of our stack to find the
 216                  * start of the child nodes for this node.
 217                  */
 218                 for (i = 0, h = &stack; i < child_port_count; i++)
 219                         h = h->prev;
 220                 /*
 221                  * When the stack is empty, this yields an invalid value,
 222                  * but that pointer will never be dereferenced.
 223                  */
 224                 child = fw_node(h);
 225
 226                 node = fw_node_create(q, port_count, card->color);
 227                 if (node == NULL) {
 228                         fw_error("Out of memory while building topology.\n");
 229                         return NULL;
 230                 }
 231
 232                 if (phy_id == (card->node_id & 0x3f))
 233                         local_node = node;
 234
 235                 if (SELF_ID_CONTENDER(q))
 236                         irm_node = node;
 237
 238                 parent_count = 0;
 239
 240                 for (i = 0; i < port_count; i++) {
 241                         switch (get_port_type(sid, i)) {
 242                         case SELFID_PORT_PARENT:
 243                                 /*
 244                                  * Who's your daddy?  We dont know the
 245                                  * parent node at this time, so we
 246                                  * temporarily abuse node->color for
 247                                  * remembering the entry in the
 248                                  * node->ports array where the parent
 249                                  * node should be.  Later, when we
 250                                  * handle the parent node, we fix up
 251                                  * the reference.
 252                                  */
 253                                 parent_count++;
 254                                 node->color = i;
 255                                 break;
 256
 257                         case SELFID_PORT_CHILD:
 258                                 node->ports[i] = child;
 259                                 /*
 260                                  * Fix up parent reference for this
 261                                  * child node.
 262                                  */
 263                                 child->ports[child->color] = node;
 264                                 child->color = card->color;
 265                                 child = fw_node(child->link.next);
 266                                 break;
 267                         }
 268                 }
 269
 270                 /*
 271                  * Check that the node reports exactly one parent
 272                  * port, except for the root, which of course should
 273                  * have no parents.
 274                  */
 275                 if ((next_sid == end && parent_count != 0) ||
 276                     (next_sid < end && parent_count != 1)) {
 277                         fw_error("Parent port inconsistency for node %d: "
 278                                  "parent_count=%d\n", phy_id, parent_count);
 279                         return NULL;
 280                 }
 281
 282                 /* Pop the child nodes off the stack and push the new node. */
 283                 __list_del(h->prev, &stack);
 284                 list_add_tail(&node->link, &stack);
 285                 stack_depth += 1 - child_port_count;
 286
 287                 if (node->phy_speed == SCODE_BETA &&
 288                     parent_count + child_port_count > 1)
 289                         beta_repeaters_present = true;
 290
 291                 /*
 292                  * If all PHYs does not report the same gap count
 293                  * setting, we fall back to 63 which will force a gap
 294                  * count reconfiguration and a reset.
 295                  */
 296                 if (SELF_ID_GAP_COUNT(q) != gap_count)
 297                         gap_count = 63;
 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
 360 static void
 361 report_found_node(struct fw_card *card,
 362                   struct fw_node *node, struct fw_node *parent)
 363 {
 364         int b_path = (node->phy_speed == SCODE_BETA);
 365
 366         if (parent != NULL) {
 367                 /* min() macro doesn't work here with gcc 3.4 */
 368                 node->max_speed = parent->max_speed < node->phy_speed ?
 369                                         parent->max_speed : node->phy_speed;
 370                 node->b_path = parent->b_path && b_path;
 371         } else {
 372                 node->max_speed = node->phy_speed;
 373                 node->b_path = b_path;
 374         }
 375
 376         fw_node_event(card, node, FW_NODE_CREATED);
 377 }
 378
 379 void fw_destroy_nodes(struct fw_card *card)
 380 {
 381         unsigned long flags;
 382
 383         spin_lock_irqsave(&card->lock, flags);
 384         card->color++;
 385         if (card->local_node != NULL)
 386                 for_each_fw_node(card, card->local_node, report_lost_node);
 387         card->local_node = NULL;
 388         spin_unlock_irqrestore(&card->lock, flags);
 389 }
 390
 391 static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
 392 {
 393         struct fw_node *tree;
 394         int i;
 395
 396         tree = node1->ports[port];
 397         node0->ports[port] = tree;
 398         for (i = 0; i < tree->port_count; i++) {
 399                 if (tree->ports[i] == node1) {
 400                         tree->ports[i] = node0;
 401                         break;
 402                 }
 403         }
 404 }
 405
 406 /**
 407  * update_tree - compare the old topology tree for card with the new
 408  * one specified by root.  Queue the nodes and mark them as either
 409  * found, lost or updated.  Update the nodes in the card topology tree
 410  * as we go.
 411  */
 412 static void
 413 update_tree(struct fw_card *card, struct fw_node *root)
 414 {
 415         struct list_head list0, list1;
 416         struct fw_node *node0, *node1;
 417         int i, event;
 418
 419         INIT_LIST_HEAD(&list0);
 420         list_add_tail(&card->local_node->link, &list0);
 421         INIT_LIST_HEAD(&list1);
 422         list_add_tail(&root->link, &list1);
 423
 424         node0 = fw_node(list0.next);
 425         node1 = fw_node(list1.next);
 426
 427         while (&node0->link != &list0) {
 428                 WARN_ON(node0->port_count != node1->port_count);
 429
 430                 if (node0->link_on && !node1->link_on)
 431                         event = FW_NODE_LINK_OFF;
 432                 else if (!node0->link_on && node1->link_on)
 433                         event = FW_NODE_LINK_ON;
 434                 else
 435                         event = FW_NODE_UPDATED;
 436
 437                 node0->node_id = node1->node_id;
 438                 node0->color = card->color;
 439                 node0->link_on = node1->link_on;
 440                 node0->initiated_reset = node1->initiated_reset;
 441                 node0->max_hops = node1->max_hops;
 442                 node1->color = card->color;
 443                 fw_node_event(card, node0, event);
 444
 445                 if (card->root_node == node1)
 446                         card->root_node = node0;
 447                 if (card->irm_node == node1)
 448                         card->irm_node = node0;
 449
 450                 for (i = 0; i < node0->port_count; i++) {
 451                         if (node0->ports[i] && node1->ports[i]) {
 452                                 /*
 453                                  * This port didn't change, queue the
 454                                  * connected node for further
 455                                  * investigation.
 456                                  */
 457                                 if (node0->ports[i]->color == card->color)
 458                                         continue;
 459                                 list_add_tail(&node0->ports[i]->link, &list0);
 460                                 list_add_tail(&node1->ports[i]->link, &list1);
 461                         } else if (node0->ports[i]) {
 462                                 /*
 463                                  * The nodes connected here were
 464                                  * unplugged; unref the lost nodes and
 465                                  * queue FW_NODE_LOST callbacks for
 466                                  * them.
 467                                  */
 468
 469                                 for_each_fw_node(card, node0->ports[i],
 470                                                  report_lost_node);
 471                                 node0->ports[i] = NULL;
 472                         } else if (node1->ports[i]) {
 473                                 /*
 474                                  * One or more node were connected to
 475                                  * this port. Move the new nodes into
 476                                  * the tree and queue FW_NODE_CREATED
 477                                  * callbacks for them.
 478                                  */
 479                                 move_tree(node0, node1, i);
 480                                 for_each_fw_node(card, node0->ports[i],
 481                                                  report_found_node);
 482                         }
 483                 }
 484
 485                 node0 = fw_node(node0->link.next);
 486                 node1 = fw_node(node1->link.next);
 487         }
 488 }
 489
 490 static void
 491 update_topology_map(struct fw_card *card, u32 *self_ids, int self_id_count)
 492 {
 493         int node_count;
 494
 495         card->topology_map[1]++;
 496         node_count = (card->root_node->node_id & 0x3f) + 1;
 497         card->topology_map[2] = (node_count << 16) | self_id_count;
 498         card->topology_map[0] = (self_id_count + 2) << 16;
 499         memcpy(&card->topology_map[3], self_ids, self_id_count * 4);
 500         fw_compute_block_crc(card->topology_map);
 501 }
 502
 503 void
 504 fw_core_handle_bus_reset(struct fw_card *card,
 505                          int node_id, int generation,
 506                          int self_id_count, u32 * self_ids)
 507 {
 508         struct fw_node *local_node;
 509         unsigned long flags;
 510
 511         fw_flush_transactions(card);
 512
 513         spin_lock_irqsave(&card->lock, flags);
 514
 515         /*
 516          * If the new topology has a different self_id_count the topology
 517          * changed, either nodes were added or removed. In that case we
 518          * reset the IRM reset counter.
 519          */
 520         if (card->self_id_count != self_id_count)
 521                 card->bm_retries = 0;
 522
 523         card->node_id = node_id;
 524         /*
 525          * Update node_id before generation to prevent anybody from using
 526          * a stale node_id together with a current generation.
 527          */
 528         smp_wmb();
 529         card->generation = generation;
 530         card->reset_jiffies = jiffies;
 531         schedule_delayed_work(&card->work, 0);
 532
 533         local_node = build_tree(card, self_ids, self_id_count);
 534
 535         update_topology_map(card, self_ids, self_id_count);
 536
 537         card->color++;
 538
 539         if (local_node == NULL) {
 540                 fw_error("topology build failed\n");
 541                 /* FIXME: We need to issue a bus reset in this case. */
 542         } else if (card->local_node == NULL) {
 543                 card->local_node = local_node;
 544                 for_each_fw_node(card, local_node, report_found_node);
 545         } else {
 546                 update_tree(card, local_node);
 547         }
 548
 549         spin_unlock_irqrestore(&card->lock, flags);
 550 }
 551 EXPORT_SYMBOL(fw_core_handle_bus_reset);