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-card.c b/drivers/firewire/fw-card.c
index c8b7d69..307c8b8 100644
--- a/drivers/firewire/fw-card.c
+++ b/drivers/firewire/fw-card.c
@@ -186,14 +186,17 @@
}
EXPORT_SYMBOL(fw_core_remove_descriptor);
+static const char gap_count_table[] = {
+ 63, 5, 7, 8, 10, 13, 16, 18, 21, 24, 26, 29, 32, 35, 37, 40
+};
+
static void
fw_card_irm_work(struct work_struct *work)
{
- struct fw_card *card =
- container_of(work, struct fw_card, work.work);
+ struct fw_card *card = container_of(work, struct fw_card, work.work);
struct fw_device *root;
unsigned long flags;
- int new_irm_id, generation;
+ int root_id, new_irm_id, gap_count, generation, do_reset = 0;
/* FIXME: This simple bus management unconditionally picks a
* cycle master if the current root can't do it. We need to
@@ -206,35 +209,50 @@
generation = card->generation;
root = card->root_node->data;
+ root_id = card->root_node->node_id;
- if (root == NULL)
+ if (root == NULL) {
/* Either link_on is false, or we failed to read the
* config rom. In either case, pick another root. */
new_irm_id = card->local_node->node_id;
- else if (root->state != FW_DEVICE_RUNNING)
+ } else if (root->state != FW_DEVICE_RUNNING) {
/* If we haven't probed this device yet, bail out now
* and let's try again once that's done. */
- new_irm_id = -1;
- else if (root->config_rom[2] & bib_cmc)
+ new_irm_id = root_id;
+ } else if (root->config_rom[2] & bib_cmc) {
/* FIXME: I suppose we should set the cmstr bit in the
* STATE_CLEAR register of this node, as described in
* 1394-1995, 8.4.2.6. Also, send out a force root
* packet for this node. */
- new_irm_id = -1;
- else
+ new_irm_id = root_id;
+ } else {
/* Current root has an active link layer and we
* successfully read the config rom, but it's not
* cycle master capable. */
new_irm_id = card->local_node->node_id;
+ }
- if (card->irm_retries++ > 5)
- new_irm_id = -1;
+ /* Now figure out what gap count to set. */
+ if (card->topology_type == FW_TOPOLOGY_A &&
+ card->root_node->max_hops < ARRAY_SIZE(gap_count_table))
+ gap_count = gap_count_table[card->root_node->max_hops];
+ else
+ gap_count = 63;
+
+ /* Finally, figure out if we should do a reset or not. If we've
+ * done less that 5 resets with the same physical topology and we
+ * have either a new root or a new gap count setting, let's do it. */
+
+ if (card->irm_retries++ < 5 &&
+ (card->gap_count != gap_count || new_irm_id != root_id))
+ do_reset = 1;
spin_unlock_irqrestore(&card->lock, flags);
- if (new_irm_id > 0) {
- fw_notify("Trying to become root (card %d)\n", card->index);
- fw_send_force_root(card, new_irm_id, generation);
+ if (do_reset) {
+ fw_notify("phy config: card %d, new root=%x, gap_count=%d\n",
+ card->index, new_irm_id, gap_count);
+ fw_send_phy_config(card, new_irm_id, generation, gap_count);
fw_core_initiate_bus_reset(card, 1);
}
}