From 83db801ce8c644edee49f4364c7ebdfef1657762 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Kristian=20H=C3=B8gsberg?= Date: Fri, 26 Jan 2007 00:37:50 -0500 Subject: firewire: Implement gap count optimization. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Kristian Høgsberg Signed-off-by: Stefan Richter --- drivers/firewire/fw-topology.c | 76 +++++++++++++++++++++++++++++++++++++----- 1 file changed, 67 insertions(+), 9 deletions(-) (limited to 'drivers/firewire/fw-topology.c') diff --git a/drivers/firewire/fw-topology.c b/drivers/firewire/fw-topology.c index 684d87d9977..d3131e7d52f 100644 --- a/drivers/firewire/fw-topology.c +++ b/drivers/firewire/fw-topology.c @@ -113,6 +113,44 @@ static struct fw_node *fw_node_create(u32 sid, int port_count, int color) 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].node == NULL) + continue; + + if (node->ports[i].node->max_hops > max_child_hops) + max_child_hops = node->ports[i].node->max_hops; + + if (node->ports[i].node->max_depth > depths[0]) { + depths[1] = depths[0]; + depths[0] = node->ports[i].node->max_depth; + } else if (node->ports[i].node->max_depth > depths[1]) + depths[1] = node->ports[i].node->max_depth; + } + + node->max_depth = depths[0] + 1; + node->max_hops = max(max_child_hops, depths[0] + depths[1] + 2); +} + + /** * build_tree - Build the tree representation of the topology * @self_ids: array of self IDs to create the tree from @@ -131,6 +169,7 @@ static struct fw_node *build_tree(struct fw_card *card) struct list_head stack, *h; u32 *sid, *next_sid, *end, q; int i, port_count, child_port_count, phy_id, parent_count, stack_depth; + int gap_count, topology_type; local_node = NULL; node = NULL; @@ -140,6 +179,8 @@ static struct fw_node *build_tree(struct fw_card *card) end = sid + card->self_id_count; phy_id = 0; card->irm_node = NULL; + gap_count = self_id_gap_count(*sid); + topology_type = 0; while (sid < end) { next_sid = count_ports(sid, &port_count, &child_port_count); @@ -179,6 +220,11 @@ static struct fw_node *build_tree(struct fw_card *card) if (self_id_contender(q)) card->irm_node = node; + if (node->phy_speed == SCODE_BETA) + topology_type |= FW_TOPOLOGY_B; + else + topology_type |= FW_TOPOLOGY_A; + parent_count = 0; for (i = 0; i < port_count; i++) { @@ -223,11 +269,21 @@ static struct fw_node *build_tree(struct fw_card *card) list_add_tail(&node->link, &stack); stack_depth += 1 - child_port_count; + /* 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->gap_count = gap_count; + card->topology_type = topology_type; return local_node; } @@ -286,7 +342,8 @@ report_found_node(struct fw_card *card, int b_path = (node->phy_speed == SCODE_BETA); if (parent != NULL) { - node->max_speed = min(parent->max_speed, node->phy_speed); + node->max_speed = min((u8)parent->max_speed, + (u8)node->phy_speed); node->b_path = parent->b_path && b_path; } else { node->max_speed = node->phy_speed; @@ -329,7 +386,7 @@ static void move_tree(struct fw_node *node0, struct fw_node *node1, int port) * as we go. */ static void -update_tree(struct fw_card *card, struct fw_node *root, int *changed) +update_tree(struct fw_card *card, struct fw_node *root) { struct list_head list0, list1; struct fw_node *node0, *node1; @@ -342,7 +399,6 @@ update_tree(struct fw_card *card, struct fw_node *root, int *changed) node0 = fw_node(list0.next); node1 = fw_node(list1.next); - *changed = 0; while (&node0->link != &list0) { @@ -358,6 +414,7 @@ update_tree(struct fw_card *card, struct fw_node *root, int *changed) 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); @@ -386,7 +443,6 @@ update_tree(struct fw_card *card, struct fw_node *root, int *changed) for_each_fw_node(card, node0->ports[i].node, report_lost_node); node0->ports[i].node = NULL; - *changed = 1; } else if (node1->ports[i].node) { /* One or more node were connected to * this port. Move the new nodes into @@ -395,7 +451,6 @@ update_tree(struct fw_card *card, struct fw_node *root, int *changed) move_tree(node0, node1, i); for_each_fw_node(card, node0->ports[i].node, report_found_node); - *changed = 1; } } @@ -411,12 +466,17 @@ fw_core_handle_bus_reset(struct fw_card *card, { struct fw_node *local_node; unsigned long flags; - int changed; 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->irm_retries = 0; + card->node_id = node_id; card->self_id_count = self_id_count; card->generation = generation; @@ -433,9 +493,7 @@ fw_core_handle_bus_reset(struct fw_card *card, card->local_node = local_node; for_each_fw_node(card, local_node, report_found_node); } else { - update_tree(card, local_node, &changed); - if (changed) - card->irm_retries = 0; + update_tree(card, local_node); } /* If we're not the root node, we may have to do some IRM work. */ -- cgit v1.2.3