firewire: allocate broadcast channel in hardware

On OHCI 1.1 controllers, let the hardware allocate the broadcast channel
automatically.  This removes a theoretical race condition directly after
a bus reset where it could be possible to read the channel allocation
register with channel 31 still being unallocated.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

1 files changed, 11 insertions, 5 deletions

diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index 7c4cf6cfa746..faf2eee473b9 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -208,13 +208,19 @@ static void allocate_broadcast_channel(struct fw_card *card, int generation)
 {
         int channel, bandwidth = 0;
 
-        fw_iso_resource_manage(card, generation, 1ULL << 31, &channel,
-                               &bandwidth, true, card->bm_transaction_data);
-        if (channel == 31) {
+        if (!card->broadcast_channel_allocated) {
+                fw_iso_resource_manage(card, generation, 1ULL << 31,
+                                       &channel, &bandwidth, true,
+                                       card->bm_transaction_data);
+                if (channel != 31) {
+                        fw_notify("failed to allocate broadcast channel\n");
+                        return;
+                }
                 card->broadcast_channel_allocated = true;
-                device_for_each_child(card->device, (void *)(long)generation,
-                                      fw_device_set_broadcast_channel);
         }
+
+        device_for_each_child(card->device, (void *)(long)generation,
+                              fw_device_set_broadcast_channel);
 }
 
 static const char gap_count_table[] = {