soundwire: intel: introduce helper for link synchronization

After arming the synchronization, the SYNCGO field controls the
hardware-based synchronization between links.

Move the programming and wait for clear of SYNCGO to dedicated helper.
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/20200716150947.22119-5-yung-chuan.liao@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/soundwire/intel.c

@@ -512,6 +512,31 @@ static void intel_shim_sync_arm(struct sdw_intel *sdw)
 	mutex_unlock(sdw->link_res->shim_lock);
 }
 
+static int intel_shim_sync_go_unlocked(struct sdw_intel *sdw)
+{
+	void __iomem *shim = sdw->link_res->shim;
+	u32 sync_reg;
+	int ret;
+
+	/* Read SYNC register */
+	sync_reg = intel_readl(shim, SDW_SHIM_SYNC);
+
+	/*
+	 * Set SyncGO bit to synchronously trigger a bank switch for
+	 * all the masters. A write to SYNCGO bit clears CMDSYNC bit for all
+	 * the Masters.
+	 */
+	sync_reg |= SDW_SHIM_SYNC_SYNCGO;
+
+	ret = intel_clear_bit(shim, SDW_SHIM_SYNC, sync_reg,
+			      SDW_SHIM_SYNC_SYNCGO);
+
+	if (ret < 0)
+		dev_err(sdw->cdns.dev, "SyncGO clear failed: %d\n", ret);
+
+	return ret;
+}
+
 /*
  * PDI routines
  */
@@ -763,15 +788,8 @@ static int intel_post_bank_switch(struct sdw_bus *bus)
 		ret = 0;
 		goto unlock;
 	}
-	/*
-	 * Set SyncGO bit to synchronously trigger a bank switch for
-	 * all the masters. A write to SYNCGO bit clears CMDSYNC bit for all
-	 * the Masters.
-	 */
-	sync_reg |= SDW_SHIM_SYNC_SYNCGO;
 
-	ret = intel_clear_bit(shim, SDW_SHIM_SYNC, sync_reg,
-			      SDW_SHIM_SYNC_SYNCGO);
+	ret = intel_shim_sync_go_unlocked(sdw);
 unlock:
 	mutex_unlock(sdw->link_res->shim_lock);