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fw-topology.c

/*
 * Incremental bus scan, based on bus topology
 *
 * Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/module.h>
#include <linux/wait.h>
#include <linux/errno.h>
#include "fw-transaction.h"
#include "fw-topology.h"

#define SELF_ID_PHY_ID(q)           (((q) >> 24) & 0x3f)
#define SELF_ID_EXTENDED(q)         (((q) >> 23) & 0x01)
#define SELF_ID_LINK_ON(q)          (((q) >> 22) & 0x01)
#define SELF_ID_GAP_COUNT(q)        (((q) >> 16) & 0x3f)
#define SELF_ID_PHY_SPEED(q)        (((q) >> 14) & 0x03)
#define SELF_ID_CONTENDER(q)        (((q) >> 11) & 0x01)
#define SELF_ID_PHY_INITIATOR(q)    (((q) >>  1) & 0x01)
#define SELF_ID_MORE_PACKETS(q)           (((q) >>  0) & 0x01)

#define SELF_ID_EXT_SEQUENCE(q)           (((q) >> 20) & 0x07)

static u32 *count_ports(u32 *sid, int *total_port_count, int *child_port_count)
{
      u32 q;
      int port_type, shift, seq;

      *total_port_count = 0;
      *child_port_count = 0;

      shift = 6;
      q = *sid;
      seq = 0;

      while (1) {
            port_type = (q >> shift) & 0x03;
            switch (port_type) {
            case SELFID_PORT_CHILD:
                  (*child_port_count)++;
            case SELFID_PORT_PARENT:
            case SELFID_PORT_NCONN:
                  (*total_port_count)++;
            case SELFID_PORT_NONE:
                  break;
            }

            shift -= 2;
            if (shift == 0) {
                  if (!SELF_ID_MORE_PACKETS(q))
                        return sid + 1;

                  shift = 16;
                  sid++;
                  q = *sid;

                  /*
                   * Check that the extra packets actually are
                   * extended self ID packets and that the
                   * sequence numbers in the extended self ID
                   * packets increase as expected.
                   */

                  if (!SELF_ID_EXTENDED(q) ||
                      seq != SELF_ID_EXT_SEQUENCE(q))
                        return NULL;

                  seq++;
            }
      }
}

static int get_port_type(u32 *sid, int port_index)
{
      int index, shift;

      index = (port_index + 5) / 8;
      shift = 16 - ((port_index + 5) & 7) * 2;
      return (sid[index] >> shift) & 0x03;
}

static struct fw_node *fw_node_create(u32 sid, int port_count, int color)
{
      struct fw_node *node;

      node = kzalloc(sizeof(*node) + port_count * sizeof(node->ports[0]),
                   GFP_ATOMIC);
      if (node == NULL)
            return NULL;

      node->color = color;
      node->node_id = LOCAL_BUS | SELF_ID_PHY_ID(sid);
      node->link_on = SELF_ID_LINK_ON(sid);
      node->phy_speed = SELF_ID_PHY_SPEED(sid);
      node->port_count = port_count;

      atomic_set(&node->ref_count, 1);
      INIT_LIST_HEAD(&node->link);

      return node;
}

/*
 * Compute the maximum hop count for this node and it's children.  The
 * maximum hop count is the maximum number of connections between any
 * two nodes in the subtree rooted at this node.  We need this for
 * setting the gap count.  As we build the tree bottom up in
 * build_tree() below, this is fairly easy to do: for each node we
 * maintain the max hop count and the max depth, ie the number of hops
 * to the furthest leaf.  Computing the max hop count breaks down into
 * two cases: either the path goes through this node, in which case
 * the hop count is the sum of the two biggest child depths plus 2.
 * Or it could be the case that the max hop path is entirely
 * containted in a child tree, in which case the max hop count is just
 * the max hop count of this child.
 */
static void update_hop_count(struct fw_node *node)
{
      int depths[2] = { -1, -1 };
      int max_child_hops = 0;
      int i;

      for (i = 0; i < node->port_count; i++) {
            if (node->ports[i] == NULL)
                  continue;

            if (node->ports[i]->max_hops > max_child_hops)
                  max_child_hops = node->ports[i]->max_hops;

            if (node->ports[i]->max_depth > depths[0]) {
                  depths[1] = depths[0];
                  depths[0] = node->ports[i]->max_depth;
            } else if (node->ports[i]->max_depth > depths[1])
                  depths[1] = node->ports[i]->max_depth;
      }

      node->max_depth = depths[0] + 1;
      node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2);
}

static inline struct fw_node *fw_node(struct list_head *l)
{
      return list_entry(l, struct fw_node, link);
}

/**
 * build_tree - Build the tree representation of the topology
 * @self_ids: array of self IDs to create the tree from
 * @self_id_count: the length of the self_ids array
 * @local_id: the node ID of the local node
 *
 * This function builds the tree representation of the topology given
 * by the self IDs from the latest bus reset.  During the construction
 * of the tree, the function checks that the self IDs are valid and
 * internally consistent.  On succcess this function returns the
 * fw_node corresponding to the local card otherwise NULL.
 */
static struct fw_node *build_tree(struct fw_card *card,
                          u32 *sid, int self_id_count)
{
      struct fw_node *node, *child, *local_node, *irm_node;
      struct list_head stack, *h;
      u32 *next_sid, *end, q;
      int i, port_count, child_port_count, phy_id, parent_count, stack_depth;
      int gap_count;
      bool beta_repeaters_present;

      local_node = NULL;
      node = NULL;
      INIT_LIST_HEAD(&stack);
      stack_depth = 0;
      end = sid + self_id_count;
      phy_id = 0;
      irm_node = NULL;
      gap_count = SELF_ID_GAP_COUNT(*sid);
      beta_repeaters_present = false;

      while (sid < end) {
            next_sid = count_ports(sid, &port_count, &child_port_count);

            if (next_sid == NULL) {
                  fw_error("Inconsistent extended self IDs.\n");
                  return NULL;
            }

            q = *sid;
            if (phy_id != SELF_ID_PHY_ID(q)) {
                  fw_error("PHY ID mismatch in self ID: %d != %d.\n",
                         phy_id, SELF_ID_PHY_ID(q));
                  return NULL;
            }

            if (child_port_count > stack_depth) {
                  fw_error("Topology stack underflow\n");
                  return NULL;
            }

            /*
             * Seek back from the top of our stack to find the
             * start of the child nodes for this node.
             */
            for (i = 0, h = &stack; i < child_port_count; i++)
                  h = h->prev;
            /*
             * When the stack is empty, this yields an invalid value,
             * but that pointer will never be dereferenced.
             */
            child = fw_node(h);

            node = fw_node_create(q, port_count, card->color);
            if (node == NULL) {
                  fw_error("Out of memory while building topology.\n");
                  return NULL;
            }

            if (phy_id == (card->node_id & 0x3f))
                  local_node = node;

            if (SELF_ID_CONTENDER(q))
                  irm_node = node;

            parent_count = 0;

            for (i = 0; i < port_count; i++) {
                  switch (get_port_type(sid, i)) {
                  case SELFID_PORT_PARENT:
                        /*
                         * Who's your daddy?  We dont know the
                         * parent node at this time, so we
                         * temporarily abuse node->color for
                         * remembering the entry in the
                         * node->ports array where the parent
                         * node should be.  Later, when we
                         * handle the parent node, we fix up
                         * the reference.
                         */
                        parent_count++;
                        node->color = i;
                        break;

                  case SELFID_PORT_CHILD:
                        node->ports[i] = child;
                        /*
                         * Fix up parent reference for this
                         * child node.
                         */
                        child->ports[child->color] = node;
                        child->color = card->color;
                        child = fw_node(child->link.next);
                        break;
                  }
            }

            /*
             * Check that the node reports exactly one parent
             * port, except for the root, which of course should
             * have no parents.
             */
            if ((next_sid == end && parent_count != 0) ||
                (next_sid < end && parent_count != 1)) {
                  fw_error("Parent port inconsistency for node %d: "
                         "parent_count=%d\n", phy_id, parent_count);
                  return NULL;
            }

            /* Pop the child nodes off the stack and push the new node. */
            __list_del(h->prev, &stack);
            list_add_tail(&node->link, &stack);
            stack_depth += 1 - child_port_count;

            if (node->phy_speed == SCODE_BETA &&
                parent_count + child_port_count > 1)
                  beta_repeaters_present = true;

            /*
             * If all PHYs does not report the same gap count
             * setting, we fall back to 63 which will force a gap
             * count reconfiguration and a reset.
             */
            if (SELF_ID_GAP_COUNT(q) != gap_count)
                  gap_count = 63;

            update_hop_count(node);

            sid = next_sid;
            phy_id++;
      }

      card->root_node = node;
      card->irm_node = irm_node;
      card->gap_count = gap_count;
      card->beta_repeaters_present = beta_repeaters_present;

      return local_node;
}

typedef void (*fw_node_callback_t)(struct fw_card * card,
                           struct fw_node * node,
                           struct fw_node * parent);

static void
for_each_fw_node(struct fw_card *card, struct fw_node *root,
             fw_node_callback_t callback)
{
      struct list_head list;
      struct fw_node *node, *next, *child, *parent;
      int i;

      INIT_LIST_HEAD(&list);

      fw_node_get(root);
      list_add_tail(&root->link, &list);
      parent = NULL;
      list_for_each_entry(node, &list, link) {
            node->color = card->color;

            for (i = 0; i < node->port_count; i++) {
                  child = node->ports[i];
                  if (!child)
                        continue;
                  if (child->color == card->color)
                        parent = child;
                  else {
                        fw_node_get(child);
                        list_add_tail(&child->link, &list);
                  }
            }

            callback(card, node, parent);
      }

      list_for_each_entry_safe(node, next, &list, link)
            fw_node_put(node);
}

static void
report_lost_node(struct fw_card *card,
             struct fw_node *node, struct fw_node *parent)
{
      fw_node_event(card, node, FW_NODE_DESTROYED);
      fw_node_put(node);
}

static void
report_found_node(struct fw_card *card,
              struct fw_node *node, struct fw_node *parent)
{
      int b_path = (node->phy_speed == SCODE_BETA);

      if (parent != NULL) {
            /* min() macro doesn't work here with gcc 3.4 */
            node->max_speed = parent->max_speed < node->phy_speed ?
                              parent->max_speed : node->phy_speed;
            node->b_path = parent->b_path && b_path;
      } else {
            node->max_speed = node->phy_speed;
            node->b_path = b_path;
      }

      fw_node_event(card, node, FW_NODE_CREATED);
}

void fw_destroy_nodes(struct fw_card *card)
{
      unsigned long flags;

      spin_lock_irqsave(&card->lock, flags);
      card->color++;
      if (card->local_node != NULL)
            for_each_fw_node(card, card->local_node, report_lost_node);
      spin_unlock_irqrestore(&card->lock, flags);
}

static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
{
      struct fw_node *tree;
      int i;

      tree = node1->ports[port];
      node0->ports[port] = tree;
      for (i = 0; i < tree->port_count; i++) {
            if (tree->ports[i] == node1) {
                  tree->ports[i] = node0;
                  break;
            }
      }
}

/**
 * update_tree - compare the old topology tree for card with the new
 * one specified by root.  Queue the nodes and mark them as either
 * found, lost or updated.  Update the nodes in the card topology tree
 * as we go.
 */
static void
update_tree(struct fw_card *card, struct fw_node *root)
{
      struct list_head list0, list1;
      struct fw_node *node0, *node1;
      int i, event;

      INIT_LIST_HEAD(&list0);
      list_add_tail(&card->local_node->link, &list0);
      INIT_LIST_HEAD(&list1);
      list_add_tail(&root->link, &list1);

      node0 = fw_node(list0.next);
      node1 = fw_node(list1.next);

      while (&node0->link != &list0) {

            /* assert(node0->port_count == node1->port_count); */
            if (node0->link_on && !node1->link_on)
                  event = FW_NODE_LINK_OFF;
            else if (!node0->link_on && node1->link_on)
                  event = FW_NODE_LINK_ON;
            else
                  event = FW_NODE_UPDATED;

            node0->node_id = node1->node_id;
            node0->color = card->color;
            node0->link_on = node1->link_on;
            node0->initiated_reset = node1->initiated_reset;
            node0->max_hops = node1->max_hops;
            node1->color = card->color;
            fw_node_event(card, node0, event);

            if (card->root_node == node1)
                  card->root_node = node0;
            if (card->irm_node == node1)
                  card->irm_node = node0;

            for (i = 0; i < node0->port_count; i++) {
                  if (node0->ports[i] && node1->ports[i]) {
                        /*
                         * This port didn't change, queue the
                         * connected node for further
                         * investigation.
                         */
                        if (node0->ports[i]->color == card->color)
                              continue;
                        list_add_tail(&node0->ports[i]->link, &list0);
                        list_add_tail(&node1->ports[i]->link, &list1);
                  } else if (node0->ports[i]) {
                        /*
                         * The nodes connected here were
                         * unplugged; unref the lost nodes and
                         * queue FW_NODE_LOST callbacks for
                         * them.
                         */

                        for_each_fw_node(card, node0->ports[i],
                                     report_lost_node);
                        node0->ports[i] = NULL;
                  } else if (node1->ports[i]) {
                        /*
                         * One or more node were connected to
                         * this port. Move the new nodes into
                         * the tree and queue FW_NODE_CREATED
                         * callbacks for them.
                         */
                        move_tree(node0, node1, i);
                        for_each_fw_node(card, node0->ports[i],
                                     report_found_node);
                  }
            }

            node0 = fw_node(node0->link.next);
            node1 = fw_node(node1->link.next);
      }
}

static void
update_topology_map(struct fw_card *card, u32 *self_ids, int self_id_count)
{
      int node_count;

      card->topology_map[1]++;
      node_count = (card->root_node->node_id & 0x3f) + 1;
      card->topology_map[2] = (node_count << 16) | self_id_count;
      card->topology_map[0] = (self_id_count + 2) << 16;
      memcpy(&card->topology_map[3], self_ids, self_id_count * 4);
      fw_compute_block_crc(card->topology_map);
}

void
fw_core_handle_bus_reset(struct fw_card *card,
                   int node_id, int generation,
                   int self_id_count, u32 * self_ids)
{
      struct fw_node *local_node;
      unsigned long flags;

      fw_flush_transactions(card);

      spin_lock_irqsave(&card->lock, flags);

      /*
       * If the new topology has a different self_id_count the topology
       * changed, either nodes were added or removed. In that case we
       * reset the IRM reset counter.
       */
      if (card->self_id_count != self_id_count)
            card->bm_retries = 0;

      card->node_id = node_id;
      card->generation = generation;
      card->reset_jiffies = jiffies;
      schedule_delayed_work(&card->work, 0);

      local_node = build_tree(card, self_ids, self_id_count);

      update_topology_map(card, self_ids, self_id_count);

      card->color++;

      if (local_node == NULL) {
            fw_error("topology build failed\n");
            /* FIXME: We need to issue a bus reset in this case. */
      } else if (card->local_node == NULL) {
            card->local_node = local_node;
            for_each_fw_node(card, local_node, report_found_node);
      } else {
            update_tree(card, local_node);
      }

      spin_unlock_irqrestore(&card->lock, flags);
}
EXPORT_SYMBOL(fw_core_handle_bus_reset);

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