soundwire: bus: fix race condition with enumeration_complete signaling (fb9469e5) · Commits · 戴 / test

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>

drivers/soundwire/bus.c

+20 −0

Original line number	Diff line number	Diff line
		@@ -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);
		}

drivers/soundwire/slave.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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;

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