From fb9469e54fa7a7b6a8137c40ae66c41b8d0ab175 Mon Sep 17 00:00:00 2001 From: Pierre-Louis Bossart Date: Tue, 14 Jan 2020 18:08:36 -0600 Subject: 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 Link: https://lore.kernel.org/r/20200115000844.14695-3-pierre-louis.bossart@linux.intel.com Signed-off-by: Vinod Koul --- drivers/soundwire/bus.c | 20 ++++++++++++++++++++ drivers/soundwire/slave.c | 1 + 2 files changed, 21 insertions(+) (limited to 'drivers/soundwire') diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index 4980dfd6f3a3..a2267c3a1d2d 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -610,6 +610,26 @@ 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) && + (slave->status == SDW_SLAVE_UNATTACHED)) { + 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 08db0488e02d..e767a78066ee 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; -- cgit