soundwire: bus: fix race condition with enumeration_complete signaling
This patch adds the signaling needed for Slave drivers to wait until
the enumeration completes so that race conditions when issuing
read/write commands are avoided. The calls for wait_for_completion()
will be added in codec drivers in follow-up patches.
The order between init_completion() and complete() is deterministic,
the Slave is marked as UNATTACHED either during a Master-initiated
HardReset, or when the hardware detects the Slave no longer reports as
ATTACHED.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200115000844.14695-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
index 08db048..e767a78 100644
--- a/drivers/soundwire/slave.c
+++ b/drivers/soundwire/slave.c
@@ -46,6 +46,7 @@ static int sdw_slave_add(struct sdw_bus *bus,
slave->dev.of_node = of_node_get(to_of_node(fwnode));
slave->bus = bus;
slave->status = SDW_SLAVE_UNATTACHED;
+ init_completion(&slave->enumeration_complete);
slave->dev_num = 0;
init_completion(&slave->probe_complete);
slave->probed = false;