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@xxxxxxxxxxxxxxx>
---
drivers/soundwire/bus.c | 19 +++++++++++++++++++
drivers/soundwire/slave.c | 1 +
2 files changed, 20 insertions(+)
diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 9f03a915a09a..e34b5ed534b3 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -637,6 +637,25 @@ static void sdw_modify_slave_status(struct sdw_slave *slave,
enum sdw_slave_status status)
{
mutex_lock(&slave->bus->bus_lock);
+
+ dev_vdbg(&slave->dev,
+ "%s: changing status slave %d status %d new status %d\n",
+ __func__, slave->dev_num, slave->status, status);
+
+ if (status == SDW_SLAVE_UNATTACHED) {
+ dev_dbg(&slave->dev,
+ "%s: initializing completion for Slave %d\n",
+ __func__, slave->dev_num);
+
+ init_completion(&slave->enumeration_complete);
+
+ } else if (status == SDW_SLAVE_ATTACHED) {
+ dev_dbg(&slave->dev,
+ "%s: signaling completion for Slave %d\n",
+ __func__, slave->dev_num);
+
+ complete(&slave->enumeration_complete);
+ }
slave->status = status;
mutex_unlock(&slave->bus->bus_lock);
}
diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
index 15ac89ecae01..76fdfbd8b50d 100644
--- a/drivers/soundwire/slave.c
+++ b/drivers/soundwire/slave.c
@@ -52,6 +52,7 @@ static int sdw_slave_add(struct sdw_bus *bus,
slave->dev.type = &sdw_slave_type;
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;
--
2.20.1
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