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 "fw-transaction.h"
  25 #include "fw-topology.h"
  26
  27 #define SELF_ID_PHY_ID(q)               (((q) >> 24) & 0x3f)
  28 #define SELF_ID_EXTENDED(q)             (((q) >> 23) & 0x01)
  29 #define SELF_ID_LINK_ON(q)              (((q) >> 22) & 0x01)
  30 #define SELF_ID_GAP_COUNT(q)            (((q) >> 16) & 0x3f)
  31 #define SELF_ID_PHY_SPEED(q)            (((q) >> 14) & 0x03)
  32 #define SELF_ID_CONTENDER(q)            (((q) >> 11) & 0x01)
  33 #define SELF_ID_PHY_INITIATOR(q)        (((q) >>  1) & 0x01)
  34 #define SELF_ID_MORE_PACKETS(q)         (((q) >>  0) & 0x01)
  35
  36 #define SELF_ID_EXT_SEQUENCE(q)         (((q) >> 20) & 0x07)
  37
  38 static u32 *count_ports(u32 *sid, int *total_port_count, int *child_port_count)
  39 {
  40         u32 q;
  41         int port_type, shift, seq;
  42
  43         *total_port_count = 0;
  44         *child_port_count = 0;
  45
  46         shift = 6;
  47         q = *sid;
  48         seq = 0;
  49
  50         while (1) {
  51                 port_type = (q >> shift) & 0x03;
  52                 switch (port_type) {
  53                 case SELFID_PORT_CHILD:
  54                         (*child_port_count)++;
  55                 case SELFID_PORT_PARENT:
  56                 case SELFID_PORT_NCONN:
  57                         (*total_port_count)++;
  58                 case SELFID_PORT_NONE:
  59                         break;
  60                 }
  61
  62                 shift -= 2;
  63                 if (shift == 0) {
  64                         if (!SELF_ID_MORE_PACKETS(q))
  65                                 return sid + 1;
  66
  67                         shift = 16;
  68                         sid++;
  69                         q = *sid;
  70
  71                         /*
  72                          * Check that the extra packets actually are
  73                          * extended self ID packets and that the
  74                          * sequence numbers in the extended self ID
  75                          * packets increase as expected.
  76                          */
  77
  78                         if (!SELF_ID_EXTENDED(q) ||
  79                             seq != SELF_ID_EXT_SEQUENCE(q))
  80                                 return NULL;
  81
  82                         seq++;
  83                 }
  84         }
  85 }
  86
  87 static int get_port_type(u32 *sid, int port_index)
  88 {
  89         int index, shift;
  90
  91         index = (port_index + 5) / 8;
  92         shift = 16 - ((port_index + 5) & 7) * 2;
  93         return (sid[index] >> shift) & 0x03;
  94 }
  95
  96 static struct fw_node *fw_node_create(u32 sid, int port_count, int color)
  97 {
  98         struct fw_node *node;
  99
 100         node = kzalloc(sizeof(*node) + port_count * sizeof(node->ports[0]),
 101                        GFP_ATOMIC);
 102         if (node == NULL)
 103                 return NULL;
 104
 105         node->color = color;
 106         node->node_id = LOCAL_BUS | SELF_ID_PHY_ID(sid);
 107         node->link_on = SELF_ID_LINK_ON(sid);
 108         node->phy_speed = SELF_ID_PHY_SPEED(sid);
 109         node->port_count = port_count;
 110
 111         atomic_set(&node->ref_count, 1);
 112         INIT_LIST_HEAD(&node->link);
 113
 114         return node;
 115 }
 116
 117 /*
 118  * Compute the maximum hop count for this node and it's children.  The
 119  * maximum hop count is the maximum number of connections between any
 120  * two nodes in the subtree rooted at this node.  We need this for
 121  * setting the gap count.  As we build the tree bottom up in
 122  * build_tree() below, this is fairly easy to do: for each node we
 123  * maintain the max hop count and the max depth, ie the number of hops
 124  * to the furthest leaf.  Computing the max hop count breaks down into
 125  * two cases: either the path goes through this node, in which case
 126  * the hop count is the sum of the two biggest child depths plus 2.
 127  * Or it could be the case that the max hop path is entirely
 128  * containted in a child tree, in which case the max hop count is just
 129  * the max hop count of this child.
 130  */
 131 static void update_hop_count(struct fw_node *node)
 132 {
 133         int depths[2] = { -1, -1 };
 134         int max_child_hops = 0;
 135         int i;
 136
 137         for (i = 0; i < node->port_count; i++) {
 138                 if (node->ports[i] == NULL)
 139                         continue;
 140
 141                 if (node->ports[i]->max_hops > max_child_hops)
 142                         max_child_hops = node->ports[i]->max_hops;
 143
 144                 if (node->ports[i]->max_depth > depths[0]) {
 145                         depths[1] = depths[0];
 146                         depths[0] = node->ports[i]->max_depth;
 147                 } else if (node->ports[i]->max_depth > depths[1])
 148                         depths[1] = node->ports[i]->max_depth;
 149         }
 150
 151         node->max_depth = depths[0] + 1;
 152         node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2);
 153 }
 154
 155
 156 /**
 157  * build_tree - Build the tree representation of the topology
 158  * @self_ids: array of self IDs to create the tree from
 159  * @self_id_count: the length of the self_ids array
 160  * @local_id: the node ID of the local node
 161  *
 162  * This function builds the tree representation of the topology given
 163  * by the self IDs from the latest bus reset.  During the construction
 164  * of the tree, the function checks that the self IDs are valid and
 165  * internally consistent.  On succcess this funtions returns the
 166  * fw_node corresponding to the local card otherwise NULL.
 167  */
 168 static struct fw_node *build_tree(struct fw_card *card,
 169                                   u32 *sid, int self_id_count)
 170 {
 171         struct fw_node *node, *child, *local_node, *irm_node;
 172         struct list_head stack, *h;
 173         u32 *next_sid, *end, q;
 174         int i, port_count, child_port_count, phy_id, parent_count, stack_depth;
 175         int gap_count;
 176         bool beta_repeaters_present;
 177
 178         local_node = NULL;
 179         node = NULL;
 180         INIT_LIST_HEAD(&stack);
 181         stack_depth = 0;
 182         end = sid + self_id_count;
 183         phy_id = 0;
 184         irm_node = NULL;
 185         gap_count = SELF_ID_GAP_COUNT(*sid);
 186         beta_repeaters_present = false;
 187
 188         while (sid < end) {
 189                 next_sid = count_ports(sid, &port_count, &child_port_count);
 190
 191                 if (next_sid == NULL) {
 192                         fw_error("Inconsistent extended self IDs.\n");
 193                         return NULL;
 194                 }
 195
 196                 q = *sid;
 197                 if (phy_id != SELF_ID_PHY_ID(q)) {
 198                         fw_error("PHY ID mismatch in self ID: %d != %d.\n",
 199                                  phy_id, SELF_ID_PHY_ID(q));
 200                         return NULL;
 201                 }
 202
 203                 if (child_port_count > stack_depth) {
 204                         fw_error("Topology stack underflow\n");
 205                         return NULL;
 206                 }
 207
 208                 /*
 209                  * Seek back from the top of our stack to find the
 210                  * start of the child nodes for this node.
 211                  */
 212                 for (i = 0, h = &stack; i < child_port_count; i++)
 213                         h = h->prev;
 214                 child = fw_node(h);
 215
 216                 node = fw_node_create(q, port_count, card->color);
 217                 if (node == NULL) {
 218                         fw_error("Out of memory while building topology.\n");
 219                         return NULL;
 220                 }
 221
 222                 if (phy_id == (card->node_id & 0x3f))
 223                         local_node = node;
 224
 225                 if (SELF_ID_CONTENDER(q))
 226                         irm_node = node;
 227
 228                 parent_count = 0;
 229
 230                 for (i = 0; i < port_count; i++) {
 231                         switch (get_port_type(sid, i)) {
 232                         case SELFID_PORT_PARENT:
 233                                 /*
 234                                  * Who's your daddy?  We dont know the
 235                                  * parent node at this time, so we
 236                                  * temporarily abuse node->color for
 237                                  * remembering the entry in the
 238                                  * node->ports array where the parent
 239                                  * node should be.  Later, when we
 240                                  * handle the parent node, we fix up
 241                                  * the reference.
 242                                  */
 243                                 parent_count++;
 244                                 node->color = i;
 245                                 break;
 246
 247                         case SELFID_PORT_CHILD:
 248                                 node->ports[i] = child;
 249                                 /*
 250                                  * Fix up parent reference for this
 251                                  * child node.
 252                                  */
 253                                 child->ports[child->color] = node;
 254                                 child->color = card->color;
 255                                 child = fw_node(child->link.next);
 256                                 break;
 257                         }
 258                 }
 259
 260                 /*
 261                  * Check that the node reports exactly one parent
 262                  * port, except for the root, which of course should
 263                  * have no parents.
 264                  */
 265                 if ((next_sid == end && parent_count != 0) ||
 266                     (next_sid < end && parent_count != 1)) {
 267                         fw_error("Parent port inconsistency for node %d: "
 268                                  "parent_count=%d\n", phy_id, parent_count);
 269                         return NULL;
 270                 }
 271
 272                 /* Pop the child nodes off the stack and push the new node. */
 273                 __list_del(h->prev, &stack);
 274                 list_add_tail(&node->link, &stack);
 275                 stack_depth += 1 - child_port_count;
 276
 277                 if (node->phy_speed == SCODE_BETA &&
 278                     parent_count + child_port_count > 1)
 279                         beta_repeaters_present = true;
 280
 281                 /*
 282                  * If all PHYs does not report the same gap count
 283                  * setting, we fall back to 63 which will force a gap
 284                  * count reconfiguration and a reset.
 285                  */
 286                 if (SELF_ID_GAP_COUNT(q) != gap_count)
 287                         gap_count = 63;
 288
 289                 update_hop_count(node);
 290
 291                 sid = next_sid;
 292                 phy_id++;
 293         }
 294
 295         card->root_node = node;
 296         card->irm_node = irm_node;
 297         card->gap_count = gap_count;
 298         card->beta_repeaters_present = beta_repeaters_present;
 299
 300         return local_node;
 301 }
 302
 303 typedef void (*fw_node_callback_t)(struct fw_card * card,
 304                                    struct fw_node * node,
 305                                    struct fw_node * parent);
 306
 307 static void
 308 for_each_fw_node(struct fw_card *card, struct fw_node *root,
 309                  fw_node_callback_t callback)
 310 {
 311         struct list_head list;
 312         struct fw_node *node, *next, *child, *parent;
 313         int i;
 314
 315         INIT_LIST_HEAD(&list);
 316
 317         fw_node_get(root);
 318         list_add_tail(&root->link, &list);
 319         parent = NULL;
 320         list_for_each_entry(node, &list, link) {
 321                 node->color = card->color;
 322
 323                 for (i = 0; i < node->port_count; i++) {
 324                         child = node->ports[i];
 325                         if (!child)
 326                                 continue;
 327                         if (child->color == card->color)
 328                                 parent = child;
 329                         else {
 330                                 fw_node_get(child);
 331                                 list_add_tail(&child->link, &list);
 332                         }
 333                 }
 334
 335                 callback(card, node, parent);
 336         }
 337
 338         list_for_each_entry_safe(node, next, &list, link)
 339                 fw_node_put(node);
 340 }
 341
 342 static void
 343 report_lost_node(struct fw_card *card,
 344                  struct fw_node *node, struct fw_node *parent)
 345 {
 346         fw_node_event(card, node, FW_NODE_DESTROYED);
 347         fw_node_put(node);
 348 }
 349
 350 static void
 351 report_found_node(struct fw_card *card,
 352                   struct fw_node *node, struct fw_node *parent)
 353 {
 354         int b_path = (node->phy_speed == SCODE_BETA);
 355
 356         if (parent != NULL) {
 357                 /* min() macro doesn't work here with gcc 3.4 */
 358                 node->max_speed = parent->max_speed < node->phy_speed ?
 359                                         parent->max_speed : node->phy_speed;
 360                 node->b_path = parent->b_path && b_path;
 361         } else {
 362                 node->max_speed = node->phy_speed;
 363                 node->b_path = b_path;
 364         }
 365
 366         fw_node_event(card, node, FW_NODE_CREATED);
 367 }
 368
 369 void fw_destroy_nodes(struct fw_card *card)
 370 {
 371         unsigned long flags;
 372
 373         spin_lock_irqsave(&card->lock, flags);
 374         card->color++;
 375         if (card->local_node != NULL)
 376                 for_each_fw_node(card, card->local_node, report_lost_node);
 377         spin_unlock_irqrestore(&card->lock, flags);
 378 }
 379
 380 static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
 381 {
 382         struct fw_node *tree;
 383         int i;
 384
 385         tree = node1->ports[port];
 386         node0->ports[port] = tree;
 387         for (i = 0; i < tree->port_count; i++) {
 388                 if (tree->ports[i] == node1) {
 389                         tree->ports[i] = node0;
 390                         break;
 391                 }
 392         }
 393 }
 394
 395 /**
 396  * update_tree - compare the old topology tree for card with the new
 397  * one specified by root.  Queue the nodes and mark them as either
 398  * found, lost or updated.  Update the nodes in the card topology tree
 399  * as we go.
 400  */
 401 static void
 402 update_tree(struct fw_card *card, struct fw_node *root)
 403 {
 404         struct list_head list0, list1;
 405         struct fw_node *node0, *node1;
 406         int i, event;
 407
 408         INIT_LIST_HEAD(&list0);
 409         list_add_tail(&card->local_node->link, &list0);
 410         INIT_LIST_HEAD(&list1);
 411         list_add_tail(&root->link, &list1);
 412
 413         node0 = fw_node(list0.next);
 414         node1 = fw_node(list1.next);
 415
 416         while (&node0->link != &list0) {
 417
 418                 /* assert(node0->port_count == node1->port_count); */
 419                 if (node0->link_on && !node1->link_on)
 420                         event = FW_NODE_LINK_OFF;
 421                 else if (!node0->link_on && node1->link_on)
 422                         event = FW_NODE_LINK_ON;
 423                 else
 424                         event = FW_NODE_UPDATED;
 425
 426                 node0->node_id = node1->node_id;
 427                 node0->color = card->color;
 428                 node0->link_on = node1->link_on;
 429                 node0->initiated_reset = node1->initiated_reset;
 430                 node0->max_hops = node1->max_hops;
 431                 node1->color = card->color;
 432                 fw_node_event(card, node0, event);
 433
 434                 if (card->root_node == node1)
 435                         card->root_node = node0;
 436                 if (card->irm_node == node1)
 437                         card->irm_node = node0;
 438
 439                 for (i = 0; i < node0->port_count; i++) {
 440                         if (node0->ports[i] && node1->ports[i]) {
 441                                 /*
 442                                  * This port didn't change, queue the
 443                                  * connected node for further
 444                                  * investigation.
 445                                  */
 446                                 if (node0->ports[i]->color == card->color)
 447                                         continue;
 448                                 list_add_tail(&node0->ports[i]->link, &list0);
 449                                 list_add_tail(&node1->ports[i]->link, &list1);
 450                         } else if (node0->ports[i]) {
 451                                 /*
 452                                  * The nodes connected here were
 453                                  * unplugged; unref the lost nodes and
 454                                  * queue FW_NODE_LOST callbacks for
 455                                  * them.
 456                                  */
 457
 458                                 for_each_fw_node(card, node0->ports[i],
 459                                                  report_lost_node);
 460                                 node0->ports[i] = NULL;
 461                         } else if (node1->ports[i]) {
 462                                 /*
 463                                  * One or more node were connected to
 464                                  * this port. Move the new nodes into
 465                                  * the tree and queue FW_NODE_CREATED
 466                                  * callbacks for them.
 467                                  */
 468                                 move_tree(node0, node1, i);
 469                                 for_each_fw_node(card, node0->ports[i],
 470                                                  report_found_node);
 471                         }
 472                 }
 473
 474                 node0 = fw_node(node0->link.next);
 475                 node1 = fw_node(node1->link.next);
 476         }
 477 }
 478
 479 static void
 480 update_topology_map(struct fw_card *card, u32 *self_ids, int self_id_count)
 481 {
 482         int node_count;
 483
 484         card->topology_map[1]++;
 485         node_count = (card->root_node->node_id & 0x3f) + 1;
 486         card->topology_map[2] = (node_count << 16) | self_id_count;
 487         card->topology_map[0] = (self_id_count + 2) << 16;
 488         memcpy(&card->topology_map[3], self_ids, self_id_count * 4);
 489         fw_compute_block_crc(card->topology_map);
 490 }
 491
 492 void
 493 fw_core_handle_bus_reset(struct fw_card *card,
 494                          int node_id, int generation,
 495                          int self_id_count, u32 * self_ids)
 496 {
 497         struct fw_node *local_node;
 498         unsigned long flags;
 499
 500         fw_flush_transactions(card);
 501
 502         spin_lock_irqsave(&card->lock, flags);
 503
 504         /*
 505          * If the new topology has a different self_id_count the topology
 506          * changed, either nodes were added or removed. In that case we
 507          * reset the IRM reset counter.
 508          */
 509         if (card->self_id_count != self_id_count)
 510                 card->bm_retries = 0;
 511
 512         card->node_id = node_id;
 513         card->generation = generation;
 514         card->reset_jiffies = jiffies;
 515         schedule_delayed_work(&card->work, 0);
 516
 517         local_node = build_tree(card, self_ids, self_id_count);
 518
 519         update_topology_map(card, self_ids, self_id_count);
 520
 521         card->color++;
 522
 523         if (local_node == NULL) {
 524                 fw_error("topology build failed\n");
 525                 /* FIXME: We need to issue a bus reset in this case. */
 526         } else if (card->local_node == NULL) {
 527                 card->local_node = local_node;
 528                 for_each_fw_node(card, local_node, report_found_node);
 529         } else {
 530                 update_tree(card, local_node);
 531         }
 532
 533         spin_unlock_irqrestore(&card->lock, flags);
 534 }
 535 EXPORT_SYMBOL(fw_core_handle_bus_reset);