soundwire: cadence_master: improve PDI allocation

PDI number should match dai->id, there is no need to track if a PDI is
allocated or not.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190916192348.467-7-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 13ca305..dbe386e 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -814,7 +814,6 @@ static int cdns_allocate_pdi(struct sdw_cdns *cdns,
 
 	for (i = 0; i < num; i++) {
 		pdi[i].num = i + pdi_offset;
-		pdi[i].assigned = false;
 	}
 
 	*stream = pdi;
@@ -1166,21 +1165,20 @@ EXPORT_SYMBOL(cdns_set_sdw_stream);
  * @num: Number of PDIs
  * @pdi: PDI instances
  *
- * Find and return a free PDI for a given PDI array
+ * Find a PDI for a given PDI array. The PDI num and dai_id are
+ * expected to match, return NULL otherwise.
  */
 static struct sdw_cdns_pdi *cdns_find_pdi(struct sdw_cdns *cdns,
 					  unsigned int offset,
 					  unsigned int num,
-					  struct sdw_cdns_pdi *pdi)
+					  struct sdw_cdns_pdi *pdi,
+					  int dai_id)
 {
 	int i;
 
-	for (i = offset; i < num; i++) {
-		if (pdi[i].assigned)
-			continue;
-		pdi[i].assigned = true;
-		return &pdi[i];
-	}
+	for (i = offset; i < offset + num; i++)
+		if (pdi[i].num == dai_id)
+			return &pdi[i];
 
 	return NULL;
 }
@@ -1220,18 +1218,21 @@ EXPORT_SYMBOL(sdw_cdns_config_stream);
  */
 struct sdw_cdns_pdi *sdw_cdns_alloc_pdi(struct sdw_cdns *cdns,
 					struct sdw_cdns_streams *stream,
-					u32 ch, u32 dir)
+					u32 ch, u32 dir, int dai_id)
 {
 	struct sdw_cdns_pdi *pdi = NULL;
 
 	if (dir == SDW_DATA_DIR_RX)
-		pdi = cdns_find_pdi(cdns, 0, stream->num_in, stream->in);
+		pdi = cdns_find_pdi(cdns, 0, stream->num_in, stream->in,
+				    dai_id);
 	else
-		pdi = cdns_find_pdi(cdns, 0, stream->num_out, stream->out);
+		pdi = cdns_find_pdi(cdns, 0, stream->num_out, stream->out,
+				    dai_id);
 
 	/* check if we found a PDI, else find in bi-directional */
 	if (!pdi)
-		pdi = cdns_find_pdi(cdns, 2, stream->num_bd, stream->bd);
+		pdi = cdns_find_pdi(cdns, 2, stream->num_bd, stream->bd,
+				    dai_id);
 
 	if (pdi) {
 		pdi->l_ch_num = 0;