firewire: Implement gap count optimization.
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/fw-topology.c b/drivers/firewire/fw-topology.c
index 684d87d..d3131e7 100644
--- a/drivers/firewire/fw-topology.c
+++ b/drivers/firewire/fw-topology.c
@@ -113,6 +113,44 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
* 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 @@
node0 = fw_node(list0.next);
node1 = fw_node(list1.next);
- *changed = 0;
while (&node0->link != &list0) {
@@ -358,6 +414,7 @@
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 @@
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 @@
move_tree(node0, node1, i);
for_each_fw_node(card, node0->ports[i].node,
report_found_node);
- *changed = 1;
}
}
@@ -411,12 +466,17 @@
{
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 @@
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. */