soundwire: stream: only prepare stream when it is configured.

We don't need to prepare the stream again if the stream is already
prepared.

sdw_prepare_stream() could be called multiple times without calling
sdw_deprepare_stream(). We call sdw_prepare_stream() in the prepare
dai ops and sdw_deprepare_stream() in the hw_free dai ops. If an xrun
happens, sdw_prepare_stream() will be called but
sdw_deprepare_stream() will not, which results in an imbalance and an
invalid total bandwidth.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20200114235227.14502-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 6aa0b5d370c039fec928bfa9fa3a103421f208b5..bd0bddf738302abad9acfd68be57e70ac267ec3e 100644 (file)
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -1544,7 +1544,7 @@ restore_params:
  */
 int sdw_prepare_stream(struct sdw_stream_runtime *stream)
 {
-       int ret = 0;
+       int ret;
 
        if (!stream) {
                pr_err("SoundWire: Handle not found for stream\n");
@@ -1553,6 +1553,11 @@ int sdw_prepare_stream(struct sdw_stream_runtime *stream)
 
        sdw_acquire_bus_lock(stream);
 
+       if (stream->state == SDW_STREAM_PREPARED) {
+               ret = 0;
+               goto state_err;
+       }
+
        if (stream->state != SDW_STREAM_CONFIGURED &&
            stream->state != SDW_STREAM_DEPREPARED &&
            stream->state != SDW_STREAM_DISABLED) {