firewire: Implement compliant bus management.
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 307c8b8..f94874c 100644
--- a/drivers/firewire/fw-card.c
+++ b/drivers/firewire/fw-card.c
@@ -92,7 +92,7 @@
bib_generation(card->config_rom_generation++ % 14 + 2) |
bib_max_rom(2) |
bib_max_receive(card->max_receive) |
- bib_isc | bib_cmc | bib_imc;
+ bib_bmc | bib_isc | bib_cmc | bib_imc;
config_rom[3] = card->guid >> 32;
config_rom[4] = card->guid;
@@ -190,48 +190,137 @@
63, 5, 7, 8, 10, 13, 16, 18, 21, 24, 26, 29, 32, 35, 37, 40
};
+struct bm_data {
+ struct fw_transaction t;
+ struct {
+ __be32 arg;
+ __be32 data;
+ } lock;
+ u32 old;
+ int rcode;
+ struct completion done;
+};
+
static void
-fw_card_irm_work(struct work_struct *work)
+complete_bm_lock(struct fw_card *card, int rcode,
+ void *payload, size_t length, void *data)
+{
+ struct bm_data *bmd = data;
+
+ if (rcode == RCODE_COMPLETE)
+ bmd->old = be32_to_cpu(*(__be32 *) payload);
+ bmd->rcode = rcode;
+ complete(&bmd->done);
+}
+
+static void
+fw_card_bm_work(struct work_struct *work)
{
struct fw_card *card = container_of(work, struct fw_card, work.work);
struct fw_device *root;
+ struct bm_data bmd;
unsigned long flags;
- 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
- * not do this if there is a bus manager already. Also, some
- * hubs set the contender bit, which is bogus, so we should
- * probably do a little sanity check on the IRM (like, read
- * the bandwidth register) if it's not us. */
+ int root_id, new_root_id, irm_id, gap_count, generation, grace;
+ int do_reset = 0;
spin_lock_irqsave(&card->lock, flags);
generation = card->generation;
root = card->root_node->data;
root_id = card->root_node->node_id;
+ grace = time_after(jiffies, card->reset_jiffies + DIV_ROUND_UP(HZ, 10));
+
+ if (card->bm_generation + 1 == generation ||
+ (card->bm_generation != generation && grace)) {
+ /* This first step is to figure out who is IRM and
+ * then try to become bus manager. If the IRM is not
+ * well defined (e.g. does not have an active link
+ * layer or does not responds to our lock request, we
+ * will have to do a little vigilante bus management.
+ * In that case, we do a goto into the gap count logic
+ * so that when we do the reset, we still optimize the
+ * gap count. That could well save a reset in the
+ * next generation. */
+
+ irm_id = card->irm_node->node_id;
+ if (!card->irm_node->link_on) {
+ new_root_id = card->local_node->node_id;
+ fw_notify("IRM has link off, making local node (%02x) root.\n",
+ new_root_id);
+ goto pick_me;
+ }
+
+ bmd.lock.arg = cpu_to_be32(0x3f);
+ bmd.lock.data = cpu_to_be32(card->local_node->node_id);
+
+ spin_unlock_irqrestore(&card->lock, flags);
+
+ init_completion(&bmd.done);
+ fw_send_request(card, &bmd.t, TCODE_LOCK_COMPARE_SWAP,
+ irm_id, generation,
+ SCODE_100, CSR_REGISTER_BASE + CSR_BUS_MANAGER_ID,
+ &bmd.lock, sizeof bmd.lock,
+ complete_bm_lock, &bmd);
+ wait_for_completion(&bmd.done);
+
+ if (bmd.rcode == RCODE_GENERATION) {
+ /* Another bus reset happened. Just return,
+ * the BM work has been rescheduled. */
+ return;
+ }
+
+ if (bmd.rcode == RCODE_COMPLETE && bmd.old != 0x3f)
+ /* Somebody else is BM, let them do the work. */
+ return;
+
+ spin_lock_irqsave(&card->lock, flags);
+ if (bmd.rcode != RCODE_COMPLETE) {
+ /* The lock request failed, maybe the IRM
+ * isn't really IRM capable after all. Let's
+ * do a bus reset and pick the local node as
+ * root, and thus, IRM. */
+ new_root_id = card->local_node->node_id;
+ fw_notify("BM lock failed, making local node (%02x) root.\n",
+ new_root_id);
+ goto pick_me;
+ }
+ } else if (card->bm_generation != generation) {
+ /* OK, we weren't BM in the last generation, and it's
+ * less than 100ms since last bus reset. Reschedule
+ * this task 100ms from now. */
+ spin_unlock_irqrestore(&card->lock, flags);
+ schedule_delayed_work(&card->work, DIV_ROUND_UP(HZ, 10));
+ return;
+ }
+
+ /* We're bus manager for this generation, so next step is to
+ * make sure we have an active cycle master and do gap count
+ * optimization. */
+ card->bm_generation = generation;
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;
+ new_root_id = card->local_node->node_id;
} 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 = root_id;
+ spin_unlock_irqrestore(&card->lock, flags);
+ return;
} 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 = root_id;
+ new_root_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;
+ new_root_id = card->local_node->node_id;
}
+ pick_me:
/* 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))
@@ -243,16 +332,16 @@
* 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))
+ if (card->bm_retries++ < 5 &&
+ (card->gap_count != gap_count || new_root_id != root_id))
do_reset = 1;
spin_unlock_irqrestore(&card->lock, flags);
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);
+ card->index, new_root_id, gap_count);
+ fw_send_phy_config(card, new_root_id, generation, gap_count);
fw_core_initiate_bus_reset(card, 1);
}
}
@@ -294,7 +383,7 @@
card->local_node = NULL;
- INIT_DELAYED_WORK(&card->work, fw_card_irm_work);
+ INIT_DELAYED_WORK(&card->work, fw_card_bm_work);
card->card_device.bus = &fw_bus_type;
card->card_device.release = release_card;
diff --git a/drivers/firewire/fw-device.c b/drivers/firewire/fw-device.c
index d71824b..4ea8d4d 100644
--- a/drivers/firewire/fw-device.c
+++ b/drivers/firewire/fw-device.c
@@ -449,6 +449,8 @@
} else {
fw_notify("giving up on config rom for node id %x\n",
device->node_id);
+ if (device->node == device->card->root_node)
+ schedule_delayed_work(&device->card->work, 0);
fw_device_release(&device->device);
}
return;
diff --git a/drivers/firewire/fw-topology.c b/drivers/firewire/fw-topology.c
index fc8f1e7..27c6cb9 100644
--- a/drivers/firewire/fw-topology.c
+++ b/drivers/firewire/fw-topology.c
@@ -476,12 +476,13 @@
* 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->bm_retries = 0;
card->node_id = node_id;
card->self_id_count = self_id_count;
card->generation = generation;
memcpy(card->self_ids, self_ids, self_id_count * 4);
+ card->reset_jiffies = jiffies;
local_node = build_tree(card);
@@ -497,9 +498,7 @@
update_tree(card, local_node);
}
- /* If we're not the root node, we may have to do some IRM work. */
- if (card->local_node != card->root_node)
- schedule_delayed_work(&card->work, 0);
+ schedule_delayed_work(&card->work, 0);
spin_unlock_irqrestore(&card->lock, flags);
}
diff --git a/drivers/firewire/fw-transaction.h b/drivers/firewire/fw-transaction.h
index ad7ba32..50ec2c6 100644
--- a/drivers/firewire/fw-transaction.h
+++ b/drivers/firewire/fw-transaction.h
@@ -276,6 +276,7 @@
int current_tlabel, tlabel_mask;
struct list_head transaction_list;
struct timer_list flush_timer;
+ unsigned long reset_jiffies;
unsigned long long guid;
int max_receive;
@@ -301,9 +302,10 @@
struct list_head link;
- /* Work struct for IRM duties. */
+ /* Work struct for BM duties. */
struct delayed_work work;
- int irm_retries;
+ int bm_retries;
+ int bm_generation;
};
struct fw_card *fw_card_get(struct fw_card *card);