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