soundwire: cadence: add soft-reset on startup

Follow the recommended programming flows.

Signed-off-by: Pierre-Louis Bossart <[e-mail]>
Reviewed-by: Péter Ujfalusi <[e-mail]>
Signed-off-by: Bard Liao <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/soundwire/cadence_master.c

···
 }
 
 /**
+ * sdw_cdns_soft_reset() - Cadence soft-reset
+ * @cdns: Cadence instance
+ */
+int sdw_cdns_soft_reset(struct sdw_cdns *cdns)
+{
+	int ret;
+
+	cdns_updatel(cdns, CDNS_MCP_CONTROL, CDNS_MCP_CONTROL_SOFT_RST,
+		     CDNS_MCP_CONTROL_SOFT_RST);
+
+	ret = cdns_config_update(cdns);
+	if (ret < 0) {
+		dev_err(cdns->dev, "%s: config update failed\n", __func__);
+		return ret;
+	}
+
+	ret = cdns_set_wait(cdns, CDNS_MCP_CONTROL, CDNS_MCP_CONTROL_SOFT_RST, 0);
+	if (ret < 0)
+		dev_err(cdns->dev, "%s: Soft Reset timed out\n", __func__);
+
+	return ret;
+}
+EXPORT_SYMBOL(sdw_cdns_soft_reset);
+
+/**
  * sdw_cdns_init() - Cadence initialization
  * @cdns: Cadence instance
  */

drivers/soundwire/cadence_master.h

···
 irqreturn_t sdw_cdns_irq(int irq, void *dev_id);
 irqreturn_t sdw_cdns_thread(int irq, void *dev_id);
 
+int sdw_cdns_soft_reset(struct sdw_cdns *cdns);
 int sdw_cdns_init(struct sdw_cdns *cdns);
 int sdw_cdns_pdi_init(struct sdw_cdns *cdns,
 		      struct sdw_cdns_stream_config config);

drivers/soundwire/intel_bus_common.c

···
 	struct sdw_bus *bus = &cdns->bus;
 	int ret;
 
+	ret = sdw_cdns_soft_reset(cdns);
+	if (ret < 0) {
+		dev_err(dev, "%s: unable to soft-reset Cadence IP: %d\n", __func__, ret);
+		return ret;
+	}
+
 	/*
 	 * follow recommended programming flows to avoid timeouts when
 	 * gsync is enabled