firewire: optimize gap count with 1394b leaf nodes

Table-based gap count optimization cannot be used if 1394b repeater PHYs
are present.  But it does work with 1394b leaf nodes.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Kristian Høgsberg <krh@redhat.com>

drivers/firewire/fw-card.c

@@ -336,8 +336,11 @@ fw_card_bm_work(struct work_struct *work)
 	}
 
  pick_me:
-	/* Now figure out what gap count to set. */
-	if (card->topology_type == FW_TOPOLOGY_A &&
+	/*
+	 * Pick a gap count from 1394a table E-1.  The table doesn't cover
+	 * the typically much larger 1394b beta repeater delays though.
+	 */
+	if (!card->beta_repeaters_present &&
 	    card->root_node->max_hops < ARRAY_SIZE(gap_count_table))
 		gap_count = gap_count_table[card->root_node->max_hops];
 	else

drivers/firewire/fw-topology.c

@@ -172,7 +172,8 @@ static struct fw_node *build_tree(struct fw_card *card,
 	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, topology_type;
+	int gap_count;
+	bool beta_repeaters_present;
 
 	local_node = NULL;
 	node = NULL;
@@ -182,7 +183,7 @@ static struct fw_node *build_tree(struct fw_card *card,
 	phy_id = 0;
 	irm_node = NULL;
 	gap_count = SELF_ID_GAP_COUNT(*sid);
-	topology_type = 0;
+	beta_repeaters_present = false;
 
 	while (sid < end) {
 		next_sid = count_ports(sid, &port_count, &child_port_count);
@@ -224,11 +225,6 @@ static struct fw_node *build_tree(struct fw_card *card,
 		if (SELF_ID_CONTENDER(q))
 			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++) {
@@ -278,6 +274,10 @@ static struct fw_node *build_tree(struct fw_card *card,
 		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
@@ -295,7 +295,7 @@ static struct fw_node *build_tree(struct fw_card *card,
 	card->root_node = node;
 	card->irm_node = irm_node;
 	card->gap_count = gap_count;
-	card->topology_type = topology_type;
+	card->beta_repeaters_present = beta_repeaters_present;
 
 	return local_node;
 }

drivers/firewire/fw-topology.h

@@ -19,12 +19,6 @@
 #ifndef __fw_topology_h
 #define __fw_topology_h
 
-enum {
-	FW_TOPOLOGY_A =		0x01,
-	FW_TOPOLOGY_B =		0x02,
-	FW_TOPOLOGY_MIXED =	0x03,
-};
-
 enum {
 	FW_NODE_CREATED =   0x00,
 	FW_NODE_UPDATED =   0x01,

drivers/firewire/fw-transaction.h

@@ -245,7 +245,7 @@ struct fw_card {
 	struct fw_node *irm_node;
 	int color;
 	int gap_count;
-	int topology_type;
+	bool beta_repeaters_present;
 
 	int index;